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An Investigation of Household Refrigerator Cabinet Loads
B E Boughton A M Clausing and T A Newell
ACRCTR-21 May 1992
For additional infonnation
Air Conditioning and Refrigeration Center University of Illinois Mechanical amp Industrial Engineering Dept 1206 West Green Street Urbana IL 61801 Prepared as part ofACRC Project 19
An 1nvestigation ofRefrigeratorFreezer 1nsulation Systems (217) 333-3115 A M Clausing Principal1nvestigator
The Air Conditioning and Refrigeration Center was founded in 1988 with a grant from the estate of Richard W Kritzer the founder ofPeerless ofAmerica Inc A State of Illinois Technology Challenge Grant helped build the laboratory facilities The ACRC receives continuing support from the Richard W Kritzer Endowment and the National Science Foundation Thefollowing organizations have also become sponsors of the Center
Acustar Division of Chrysler Allied-Signal Inc Amana Refrigeration Inc Bergstrom Manufacturing Co Caterpillar Inc E I du Pont de Nemours amp Co Electric Power Research Institute Ford Motor Company General Electric Company Harrison Division of GM ICI Americas Inc Johnson Controls Inc Modine Manufacturing Co Peerless of America Inc Environmental Protection Agency U S Army CERL Whirlpool Corporation
For additional information
Air Conditioning amp Refrigeration Center Mechanical amp Industrial Engineering Dept University ofIllinois 1206 West Green Street Urbana IL 61801
2173333115
AN INVESTIGATION OF HOUSEHOLD REFRIGERATOR CABINET LOADS
Brian Edward Boughton MS
Department of Mechanical and Industrial Engineering University of Illinois at Urbana-Champaign 1992
ABSTRACT
This thesis presents an analysis of the cabinet loads of a typical household refrigerator
freezer The thennalload on the cabinet during closed door conditions is investigated The
area of greatest focus is the door and wall edge region of the refrigerator where thennal
losses are greatest Conduction heat transfer into the refrigerator cabinet is quantified using
numerical computer simulations and experimental measurements The overall cabinet load
is detennined as well as specific loads for various pathways that sum to equal the total
Based on agreement between simulations and experiments the complete edge loss accounts
for approximately 30 of the overall cabinet load on the fresh food and freezer
compartments In addition to this primary finding percentages for heat leakage directly
through the door gaskets along the steel casing at the wall and door flanges along the steel
skin in the mullion section due to the presence of a mullion anti-sweat heater and due to
the presence of an anti-sweat condenser tube are detennined
iii
T ABLE OF CONTENTS
Page
LIST OF TABLESvii
LIST OF FIGURES viii
1 INTRODUCTION 1
2 LITERATURE REVIEW5
3 ONE-DIMENSIONAL WALL AND DOOR LOADS 7
31 One-dimensional Heat Transfer ModeL 7 32 Determination of Effective Heat Transfer Coefficients 8 33 Results 10
4 EXPERIMENTAL ANAL YSIS 12
41 Temperature Profile Measurements 12 42 Thermopile Testing 14 43 Thermocouple Drag Testing 16 44 Experimental Determination of qwall and qdoor 19 45 Experimental Determination of qmulloff 21 46 Experimental Determination of qmullon 24 47 Determination of qmisc 27
5 NUMERICAL SIMULATION28
51 Wall Model 28 52 Wall Simulation to Determine qwall 32 53 Wall Edge Simulation to Determine qtube 36 54 Door Seal Simulation to Determine qseal 40
6 DISCUSSION OF RESULTS 46
61 Comparison of Simulation Results with Experimental Data 48 62 Mullion Analysis 49 63 Seal Analysis 49 64 Anti-sweat Condenser Tube Analysis 49 65 Overall Cabinet Load 50
7 SUMMARY OF CONCLUSIONS 54
REFERENCES 55
v
TABLE OF CONTENTS (CONTINUED)
Page APPENDIX A FUMED SILICA INVESTIGATION 56
Al Introduction56 A2 Thermal Properties 56 A3 Experimental Method 57 A4 Theory57 A5 Test Apparatus 59 A6 Results 61 A7 Conclusions 65 A8 Thermal Diffusivity Newton-Raphson Iteration Source Code 65
APPENDIX B ONE-DIMENSIONAL SIMULATION SOURCE CODE AND OUTPUT 69
Bl Source Code 69 B2 Output 71
APPENDIX C TEST REFRIGERATOR DESCRIPTION 73
APPENDIX D DATA ACQUISITION AND CONTROL SYSTEM 77
APPENDIX E EXPERIMENTAL DATA AND PLOTS 79
El Temperature Profile Plots From Fixed Thermocouples 79 E2 Thermopile Data Reduction 81 E3 Experimental Determination of qwall and qdoor Details 82 E4 Temperature Profile Plots From Mullion Data (Heater Off) 84 E5 Temperature Profile Plots From Mullion Data (Heater On) 87
APPENDIX F NUMERICAL SIMULATION EQUATIONS AND CODE 92
Fl Finite-Difference Equations 92 F2 Wall Simulation Source Code 94 F3 Fresh Food Wall Simulation Output 102 F4 Freezer Wall Simulation Output 108 F5 Fresh Food Wall Simulation Output Including
Anti-sweat Condenser Tube 115 F6 Freezer Wall Simulation Output Including
Anti-sweat Condenser Tube 120 F7 Seal Simulation Source Code and Output 125
vi
LIST OF TABLES
Page
31 One-dimensional Model Parameters 8 32 Results from One-dimensional Load Analysis 10
41 Thermopile Output 16 42 Experimental Determination of qwall and qdoor 20 43 Experimental Results from Mullion Analysis 24 44 Experimental Results from Heater Analysis 26 45 Miscellaneous Loads 27
51 Wall Simulation Input 30 52 Input Values 32 53 Wall Simulation Results 33 54 Wall With Condenser Tube Simulation Results 36 55 Seal Simulation Input 42 56 Seal Simulation Results 43
61 Comparison of Simulation and Experimental Values for qwall and qdoor 48 62 Overall Cabinet Loads 51
A1 Average Fumed Silica Conductivity for Various Bulk Densities 63 A2 Average Fumed Silica Diffusivity for Various Bulk Densities 64
E1 Thermopile Raw Data 82
F1 Model Resistors 92
V1l
LIST OF FIGURES
Page 11 Door Seal Region Cross Section 3 12 Mullion Region Cross Section 4
31 Model Used To Calculate One-dimensional Load 7
41 SteelSkin Temperature Profile Thermocouple Placement 12 42 Steel Skin Temperature Plot for Fresh Food Compartment 13 43 Steel Skin Temperature Plot for Freezer 14 44 Thermopile Test Apparatus 15 45 Thermopile Placement ~ 16 46 Thermocouple Drag Test Apparatus 17 47 Drag Profiles (Fresh Food) 18 48 Drag Profiles (Freezer) 19 49 Heat Flow Paths in Mullion 21 410 Mullion Face Plate Cross Section 22 411 Mullion Temperature Profile 23 412 Electric Heater Location 25 413 Mullion Temperature Profile With Heater On (Center) 26
51 Wall Heat Conduction Model Sketch 29 52 Non-adiabatic Door Seal 31 53 Fresh Food Wall Temperature Distribution 34 54 Freezer Wall Temperature Distribution 35 55 Tube Location for Simulation 36 56 Fresh Food Wall Temperature Distribution
Including Warm Anti-sweat Tube 37 57 Freezer Wall Temperature Distribution
Including Warm Anti-sweat Tube 38 58 Load Due to Condenser Tube for Various Tube Placements 39 59 ~ercentage of Heat Entering Cabinet for Various Tube Placements 39 510 Seal Simulation Mesh Layout 40 511 Seal Cavity Mesh Details 41 512 Seal Temperature Distribution (Fresh Food) 44 513 Seal Temperature Distribution (Freezer) 45
61 Refrigerator System Load Graph 46 62 Cabinet Loads Graph 47
A1 Fumed Silica Test Apparatus 59 A2 Fumed Silica Test Facility Schematic 60 A3 Time vs Temperature for Unpacked Run 61 A4 Natural Log Time vs Temperature for Unpacked Run 62 A5 Conductivity vs Bulk Density 63 A5 Diffusivity vs Bulk Density 64
viii
LIST OF FIGURES (CONTINUED)
Page
C1 Location of Anti-sweat Devices and Overall Dimensions of Test Refrigerator 73
C2 Fresh Food Compartment Interior Dimensions 74 C3 Fresh Food Door75 C4 Freezer Interior Dimensions 76 C5 Freezer Door76
D1 Data Acquisition and Control System 78
E1 Steel Skin Temperature Plot for Fresh Food Compartment (Run 2) 79 E2 Steel Skin Temperature Plot for Fresh Food Compartment (Run 3) 80 E3 Steel Skin Temperature Plot for Freezer (Run 2) 80 E4 Steel Skin Temperature Plot for Freezer (Run 3) 81 E5 Mullion Temperature Profile Run 2 (Heater Off) 84 E6 Mullion Temperature Profile Run 3 (Heater Off) 85 E7 Mullion Temperature Profile Run 4 (Heater Off) 85 E8 Mullion Temperature Profile Run 5 (Heater Off) 86 E9 Mullion Temperature Profile Run 2 (CenterHeater On) 87 E10 Mullion Temperature Profile Run 3 (CenterHeater On) 88 E11 Mullion Temperature Profile Run 1 (LeftHeater On) 88 E12 Mullion Temperature Profile Run 2 (LeftHeater On) 89 E13 Mullion Temperature Profile Run 3 (LeftHeater On) 89 E14 Mullion Temperature Profile Run 1 (RightHeater On) 90 E15 Mullion Temperature Profile Run 2 (RightHeater On) 90 E16 Mullion Temperature Profile Run 3 (RightHeater On) 91
F1 Generic Nodal Resistor Network 92
IX
I
I I
I
I
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I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I
I I I I I I I I I I I I I I I I I I I I I I
1 INTRODUCTION
New regulations recently announced by the Department ofEnergy call for substantial
energy efficiency increases for household appliances by 1993 The refrigerator is of
particular interest since it is the largest household consumer of electricity and accounts for a
large part of the 8 of the electricity used in the US for food-cooling both residential and
commercial In addition to efficiency standards regulations are being imposed on the use
of CFCs completely banning their use by the year 2000 (Braswell 1988)
The objective of this thesis is to present an analysis of all heat transfer paths from the
surroundings to the interior food compartments of the refrigerator under closed door
conditions Both experimental and numerical methods are used as a means to determine the
overall cabinet load as well as the load due to each pathway The study is focused on a
particular unit for practical purposes However the methods implemented may be applied
to any make or model to aid in the search for high efficiency cabinets
All loads determined in this study are strictly cabinet loads and not the loads seen by the
refrigerator system The thermal load on the cabinet is comprised of three main parts (i)
the load due to the one-dimensional heat transfer through the walls and doors to the food
compartments away froin the edges (ii) the load due to edge effects that is heat transfer
into the food storage compartments via paths around the perimeter of the cabinet aperture
and (iii) other miscellaneous sources
(11)
The determination of qlD is straightforward and is discussed in detail in Chapter 3 The
edge load must be broken down into several parts for examination
qedge = qwall + qdoor + qseal + qrnullon + qtubeave (12)
where
qwall heat input due to conduction along the wall steel flange
qdoo heat input due to conduction along the door steel flange
qseal heat conduction directly through the door seal
1
heat input due to conduction in the mullion region with the additional input from an anti-sweat heater
qtubeave heat input due to cabinet anti-sweat condenser tube averaged over the cycle time
heat input due to cabinet anti-sweat condenser tube
heat input due to conduction in the mullion region electric heater off
It is assumed that an electric anti-sweat heater in the mullion region is in use for the entire
cycle The test unit chosen for this study required this region to be heated almost
continually to eliminate condensation This load is represented by qmulloo in Eq (12)
The load qmulloff is due to heat conduction to the interior compartments at the mullion
region when the electric heater is off Although this value does not appear in the edge load
definition it is still important to detennine for sake of comparison with the value of
qmulloo The load due to the presence of an anti-sweat condenser loop around the aperture
of the cabinet is defmed as qtube Since this load is present for the on cycle only it must be
integrated over the cycle time to be included in Eq (12) hence the tenn qtubeave
The tenn qroisc is expressed as
qmisc = qfanave + qdefrostave + qcompave (13)
where
qfanave heat input from the evaporator fan averaged over the cycle time
qdefrostave heat input from the defrost heaters averaged over defrost cycle time
qcompave heat input from elevated exterior walls near the running compressor
Figure 11 is a cross sectional drawing of the door seal area of the test refrigerator
examined to detennine qwalI qdoor and~ The figure includes materials and their
properties taken from Incropera and Dewitt (1985)
2
400 ~I-I~ 065~
065 Only dimension that is different for the freezer
200
kltWIm-K)
Outer Steel Skin 540 312~ Polyurethane Wall Insulation 0027 0015- Inner Plastic Skin 015 009~
~ Rubber Gasket 03 017fm1I ~ ~ Glass Fiber Door Insulation 004 0023
All dimensions in millimeters
1 in= 254mm
Fig 11 Door Seal Region Cross Section
3
Figure 12 is a drawing of the mullion region cross section of the test refrigerator examined
to detennine ltlmullon and ltlmulloff
FREEZER
Freezer Gasket
Fresh Food Gasket
FRESH FOOD COMPARTMENT
Fig 12 Mullion Region Cross Section
The remainder of this thesis is devoted to the analysis of the closed door cabinet loads and
the experimental and numerical techniques used for their detennination
An experimental investigation of fumed silica as an alternative insulation for the refrigerator
is presented in Appendix A Although this appears to be a departure from the main topic
a relation exists The desire of higher efficiency requires a search for equal if not better
cabinet insulations that do not incorporate the use of ozone damaging CFCs Testing is
done to detennine the thennal conductivity and diffusivity of fumed silica for several
densities
4
2 LITERATURE REVIEW
The new energy standards imposed by the Department ofEnergy have sparked research in
the area of refrigerator efficiency and alternative refrigerants A study by Turiel and
Heydari (1988) focused on several ways to improve the efficiency of refrigerator-freezers
and freezers
Various classes for the study were chosen however the paper presents extensive results for
the most common variety a top-mounted automatic defrost refrigeratorfreezer The
design options considered were those changes that can be incorporated into the existing
refrigerator design Two types of improvements are noted (i) changes that increase energy
efficiency by decreasing the heat transfer into the cabinet and (ii) changes that increase the
efficiency by reducing auxiliary electricity use or improving the refrigeration system Type
(i) changes include Foam insulation substitution increased insulation thickness double
door gaskets improved foam insulation evacuated insulation panels and reduced heat load
of through-the-door feature Type (ii) changes include High efficiency compressor
substitution adaptive defrost fan and fan motor improvement anti-sweat heater switch
increased evaporator surface area hybrid evaporator enhanced heat transfer surfaces
mixed refrigerants improved expansion valve fluid control valve two-compressor system
use of natural convective currents and location of compressor condenser and evaporator
fan motor
Turiel and Heydari used a model developed by Little (1982) to carry out the energy use
simulations This model is a steady-state energy use simulation which computes the heat
leakage to the cabinet and then determines the energy needed to maintain the interior
ambient temperatures dictated by the OOE test procedure Turiel and Heydari present the
energy consumption figures for a 18 cubic foot top-mounted automatic defrost
refrigeratorfreezer as a baseline case They find that 74 of the total energy is accounted
for by the compressor 11 is for the anti-sweat heaters 10 is for the fans and 5 is
for the defrost heaters for a total of 947 kWhyr Also about 10 of the compressor
energy use is for the removal of internal heat generated by the evaporator fan motor defrost
heater and anti-sweat heaters
Several subsequent simulations were performed each time adding a design option that was
projected to improve efficiency The improvement levels were added cumulatively and
results were given on compressor run time heat leakage rate into the cabinet compressor
5
power demand at the operating point fan motor operating power for the evaporator and
condenser fans anti-sweat heater power and total daily and annual energy consumption
The goal here was to achieve by the last level of improvement the minimum energy
consumption that is technologically feasible One important fmding for all product classes
tested the highest efficiency was obtained by the use of evacuated panels in the planar
walls For example for the top-mounted automatic defrost unit the minimum energy use
was 515 kWyr
Finally an energy usevolume relation was developed from a linear regression obtained
from simulation results The resulting fit was shown as
Energy Use = Cl + C2Adjusted Volume
The constant Cl indicates the direct energy use to remove the cabinet loads associated with
the fan motors and heaters The slope C2 is an indicator of the rate of change ofenergy use
with a change in the adjusted volume This value reflects the rate of cabinet heat gain The
adjusted volume is the volume of the fresh food compartment plus 163 times the volume
of the freezer Turiel and Heydari produced a series of regressions for all of the defined
levels of design improvements allowing easy comparison at a specific adjusted volume
6
3 ONE-DIMENSIONAL WALL AND DOOR LOADS
In this section the overall steady cabinet load is calculated without considering the addition
of edge loading This load qlD is dermed as the heat transfer from the exterior
environment to the interior of the refrigerator under nonnal closed-door operating
conditions through four primary conductive paths (i) fresh food compartment walls (ii)
freezer walls (iii) fresh food door and (iv) freezer door In a later chapter the load due to
edge loading will be examined more closely
31 One-dimensional Heat Transfer Model
The steady conductive heat transfer through the walls of the refrigerator cabinet is
computed using a simple computer program written by Qausing (1983) This program
estimates inside and outside effective heat transfer coefficients using a flat plate natural
convection correlation Using these coefficients and the material properties and dimensions
of the wall insulation the one-dimensional heat transfer through the cabinet walls is
approximated for the fresh food and freezer compartments Figure 31 shows the
resistances and boundary conditions use in the model
Fig 31 Model Used To Calculate One-dimensional Load
7
The model provides flexibility for varying several parameters This allows application to
various types of refrigerator walls and doors Table 31 lists the input and output
parameters for the model The source code of the simulation along with the output for
completed runs are included in Appendix B
Table 31 One-dimensional Model Parameters
Input Parameters
To K (F) Room ambient temperature
Ti K (F) Interior ambient temperature
LiDs m (ft) WalVdoor insUlation thickness
kiDs Wm-K (Btuhr-ft-F) WalVdoor insulation thermal conductivity
A m2 (ft2) Cabinet surface area
Output
beo Wm2K (Btuhr-ft2_F) Exterior convective heat transfer coefficient
bei Wm2K (Btuhr-ft2-F) Interior convective heat transfer coefficient
hro Wm2K (Btuhr-ft2_F) Exterior effective radiative heat transfer coefficient
hri Wm2-K (Btuhr-ft2_F) Interior effective radiative heat transfer coefficient
qlD W (Btuhr) Heat transfer rate through specified section
32 Determination of Effective Heat Transfer Coefficients
The simulation developed automatically estimates the inside and outside effective heat
transfer coefficients This effective value is the sum of the convective and radiative
components which are defined below
The radiative heat transfer coefficients are computed iteratively using eqs (31) and (32)
assuming (i) gray walls at temperatures T wi or Two with emissivities poundi and Eo (ii) black
surroundings at Ti or To and (iii) walls can see surroundings only
(31)
(32)
8
The convective heat transfer coefficients are estimated from a flat plate natural convection
correlation developed by Clausing (1983) In the laminar regime (Ra lt 1()9) the Nusselt
number based on the film temperature is given by Eq (33)
NUf = 052 Ra4 (33)
For the turbulent regime (Ra ~ 109) the Nusselt number becomes
NUf = 009 Raf3 (34)
where in both cases
Tw+T_ Film temperature T f == 2
Lc == Vertical surface characteristic length g == Gravitational acceleration f3 == Thermal expansion coefficient v == Kinematic viscosity Tw == Vertical wall surface temperature T_ == Outsideinside ambient temperature
kf == Air thermal conductivity
The film temperature characteristic length Nusselt number and Rayleigh number will
have different values for the inside surface compared with the outside surface of the
cabinet Therefore the inside and outside convective heat transfer coefficients are
determined separately from eqs (35) and (36)
(35)
- NUfo kfohco - (36)Leo
9
33 Results
The four primary regions analyzed are (i) the fresh food compartment walls (ii) fresh food
door (iii) freezer walls and (iv) the freezer door The values for the input parameters
ltLins kins A) are taken from a full-size unit that is used for the experimental analysis
presented in Chapter 4 The room temperature is used for the model parameter To Also
the fresh food ambient Tee and the freezer ambient Tfz are substituted for Ti when
suitable in order to closely simulate real operating conditions The results are given in
Table 32
Table 32 Results From One-dimensional Load Analysis
Input
Section TooC eF)
Tj degC eF)
Lins m (ft)
kins Wm-K (Btuhr-ft-OF)
A m2 (fi2)
Fresh Food 21 4 0045 0027 242 Walls (698) (392) (0148) (0015) (2605)
Fresh Food 21 4 0040 0040 089 Door (698) (392) (0131) (0023) (958)
Freezer 21 -10 0056 0027 110 Walls (698) (-140) (0184) (0015) (1184)
Freezer 21 -10 0040 0040 034 Door (698) (-140) (0131) (0023) (366)
Output
Section hco Wm2-K cBtuhr-ft2-Fl
hro Wm2-K iJtuhr -ft2-Fgt
hci Wm2-K (Btuhr-ft2-F)
hri Wm2-K 1Btuhr-ft2-F)
qlD W (Btuhr)
Fresh Food 130 544 198 461 209 Walls (23) (96) (35) (81) (713)
Fresh Food 144 542 218 463 117 Door (25) (95) (38) (82) (399)
Freezer 143 542 226 397 143 Walls (25) (95) (39) (70) (488)
Freezer 164 538 259 400 81 Door (29) (94) (46) (70) (276)
herro =687 Wm2 K (121 Btulhr-ft2-OF) Total qlD =550 W herrrr = 670 Wm2 K (118 Btulhr-ft2_0F) (1876 Btuhr)
herrrz = 641 Wm2 K (113 Btulhr-ft2-OF)
The load for our operating conditions is 550 W (1876 Btuhr) Once again this quantity
does not reflect the total cabinet load on the refrigerator cabinet Edge effects are analyzed
in detail in the following chapters Another important result is the values for the effective
10
inside and outside heat transfer coefficients which are simply the sum of the convective
and radiative components The outside coefficient is heffo the fresh food coefficient is
heffff and the freezer coefficient is hefffz These numbers are used whenever film
coefficients are needed for computations
11
4 EXPERIMENT AL ANALYSIS
This section presents an experimental study performed on a full-size household
refrigerator In Chapter 3 we defined the load due to heat transfer through the walls and
doors of the cabinet as qlD The purpose of this experimental analysis is to quantify qwalh
qdoor qmulloff and Qrnullon and Qmisc Three types of tests are performed to accomplish
this task Descriptions of each are presented separately in the sections that follow
41 Temperature Profile Measurements
The refrigerator is instrumented with many thermocouples in various key areas to give
temperatures across the steel skin and to compare and verify the thermopile tests outlined
in the next section The four primary paths along the steel flange that are examined are the
wall-side fresh food door-side fresh food wall-side freezer and the door-side freezer
Five Type T 36 AWG thermocouples are placed along the skin for each path Figure 41
is a detailed drawing of the location of the thermocouples
Wall side TICs Door side TICs with 5 mm spacing with 5 mm spacing
Fig 41 Steel Skin Temperature Profile Thermocouple Placement
The wire leads are oriented so they run perpendicular to the temperature gradient so as to
reduce any effects of conduction along the wire to the bead The temperature data are fed to
the data acquisition system Each channel is a thermocouple input and is scanned at a rate
of 5 times a second The data are smoothed automatically by the software in blocks of 10
12
points for an average temperature every 2 seconds A full description of the data
acquisition and control system is provided in Appendix D
Data are collected for several runs to provide a good base to detennine average values since
the test conditions vary slightly from run to run To get a good measurement of the
temperature profIles along the steel flange the unit is shut off at the beginning of the run
and allowed to drift to quasi-steady conditions The presence of a large amount of thennal
mass (see Appendix C) within the refrigerator provides for a stable interior ambient
temperature during data collection The outer ambient is controlled by the room thennostat
which keeps the laboratory at a constant temperature to within plusmn1degC
Figure 42 is an example plot of a run that gives the temperature profIles along the steel
skin on the wall-side and door-side for the fresh food compartment
193
192
G 191 ~
i 19
middot5 189F
188
Run I iii --0 - Door Profile
~Imiddotmiddotmiddotmiddotmiddotmiddotmiddott 0 Wall Profue
i ~ i - - T =19273 - 001206x i i-- door i If ~
=-r~r==L~r=I ~ I +~~=~~~~~~~~~ middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot
Outdoor Ambient = 210 degC Fresh Food Ambient =48 degC
187-+----+----J------I----+---~
o 5 10 15 20 25
x (mm) 1 in= 254 mm
Fig 42 Steel Skin Temperature Plot for Fresh Food Compartment
The dashed line represents a linear least-squares fit for the door data and the solid line is the
corresponding fit for the cabinet wall data Each data point in the plot represents the
average temperature at that point over a period of time at quasi-steady conditions
Similarly Figure 43 is a plot of the temperature profIles for the freezer
13
186
184
a 182
~
i 18
5 178~
176
174
Run 1 t-- 1 1 --0 - Door Profde
P~P1 0 Wall Profile
- -LLl--=-+--shy- - Tdo = 18606 - O02354x i
or ~
=c==-rc1 1 ltb 1 ~
~~r--r- -r---shy0 5 10 15 20 25
x (mm) 1 in= 2S4mm
Fig 43 Steel Skin Temperature Plot for Freezer
A total of six separate runs were perfonned three for the fresh food compartment and three
for the freezer Plots for the other runs are located in Appendix E
From the figures above for the fresh food compartment the slope on the wall-side is
slightly steeper than the slope on the door-side In fact this trend is seen for all the runs
Therefore the heat conduction along the metal skin into the cabinet along the wall is
somewhat greater than that of the door For the freezer the slopes are nearly equal hence
the heat conduction along the wall skin and the door skin are nearly the same
42 Thermopile Testing
Another simple but important test is the use of a thennopile to measure the average
temperature difference at various locations on the steel flange regions of the unit Figure
44 is a schematic of the thennopile test set-up The thennopile is constructed from 36
AWG copperconstantan thennocouple wire
14
-
CopperConstan$t Junctions 285 mPt
IOmm
10mmThermopile
IOmm
Digital Multimeter
1 in= 254mm
Fig 44 Thermopile Test Apparatus
Five junctions are used for the fresh food compartment and three for the freezer The
junctions are mounted 10 mm (039 in) apart from one another along the steel skin beneath
the door seal Figure 45 is a detailed drawing of the lateral location of the thermopile
junctions
15
1 in =254 mm
Fig 45 Thermopile Placement
The thennopile provides an average temperature difference across the junctions The
output voltage must frrst be divided by the number of pairs of junctions and then translated
into a temperature difference using a referencing chart for the thennocouple wire Table
41 is a summary of the results from these tests The output voltages are read accurately to
within plusmn0002 mV The raw data and data reduction procedure are given in Appendix E
Table 41 Thermopile Output
Test Conditions Fresh Food aT Freezer aT TodegC
(OF) TffoC
(OF) Tfzoc
(OF) aTwallff degC
(Of) aTdoorffoc
(OFgt aTwallfzoC
(Of) aTdoorfzoC
(OFgt
1 210 (698)
48 (406)
-88 (162)
026 (047)
024 (043)
037 (067)
041 (074)
2 210 (698)
37 (387)
-87 (163)
027 (049)
026 (047)
038 (068)
040 (072)
3 208 (694)
37 (387)
-93 (153)
027 (049)
026 (047)
038 (068)
040 ( 072)
Average Values 209 (696)
40 (392)
-90 (158)
0267 (0481)
0253 (0455)
0377 (0679)
0403 (0725)
43 Thermocouple Drag Testing
One final technique applied is thennocouple drag testing This is a more qualitative method
to supply insight into what exactly is happening when the compressor is pumping wann
16
refrigerant through the anti-sweat tube that lines the perimeter of the cabinet aperture The
main objective of this test is not to give accurate temperature proftle infonnation but
instead to detennine the placement of the condenser tube This is needed as an input for
the numerical simulation of this region The reason that the temperature are not accurate is
the fact that the thermocouple is being dragged across a surface where good thermal contact
may not occur and significant energy may be generated Figure 46 is a schematic of the
apparatus used for drag testing
Power Supply
Data Acquisition System
Outer Metal Skin
Potentiometer
Inner Plastic Skin
Condenser Tube
Fig 46 Thermocouple Drag Test Apparatus
This device is quite simple yet very effective The type T 36 AWG thennocouple begins
at the interior boundary of the steel skin beneath the seal on the wall-side of the cabinet
The potentiometer is turned by hand moving the thennocouple oqtward along the skin
The temperature and location are stored simultaneously this way The thennocouple is kept
17
pressed against the steel flange by the seal The linear translation of the thennocouple is a
function of the output voltage Voutbull
s = 2mllT Vout (41)Yin
r =radius of potentiometer post =30 mm (012 in)
nT = total number of turns of potentiometer = 10
Vin = input voltage = 05 V
Vout = output voltage
Drag tests are run on the wall steel skin for both the fresh food compartment and the
freezer Runs are perfonned at four separate times the first being when the compressor
turns on Figure 47 is a plot of the drag proflles across the wall-side skin in the fresh food
compartment Figure 48 is a plot of the profiles in the freezer compartment The same
trends are generally seen for both regions The freezer profiles are simply shifted down in
temperature values as expected The temperature peak seems to move through time to
settle near the center of the flange region under the seal
31
30
29
G
i 28~
27
26~
25
24
23
e
Ji ~ i i i 1middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotlmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddoti~~
---l- Time 4
o Time 2 rr
i
0 5 10 15 20 x (mm)
Fig 47 Drag Profiles (Fresh Food)
18
26~--------+---------~-------4--------~
i ~
Time 1 24
22
20
18
16~~------+---------~-------4--------~
4 __
~~Time3
middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot_middotmiddot_middotmiddotimiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot
Outer Seal Edge o
o 5 10 15 20
x (mm)
Fig 48 Drag Profiles (Freezer)
44 Experimental Determination of qwall and qdoor
The results from the temperature profile and thennopile testing are used to detennine qwall
and qdoor according to the following defmitions
qwall = qwallff + qwallfz (42)
(43)
Where qwal1ff = heat conduction along wall-side fresh food compartment steel flange
qwallfz = heat conduction along wall-side freezer compartment steel flange
qdoorff = heat conduction along door-side fresh food compartment steel flange
qdoorfz = heat conduction along door-side freezer compartment steel flange
The trends derived from the fixed profiles exhibit generally good agreement with the
temperature differences seen by the thennopile For the fresh food compartment the
thennopile displays a slightly larger AT than what is seen in the profiles and both give a
19
slightly larger temperature difference for the wall-side compared with the door-side For
the freezer the temperature differences match closely on the wall-side however the doorshy
side AT is shown to be somewhat less than the wall-side AT for the fIXed thennocouple
measurements where the opposite is seen from the thennopile The worst discrepancy is
on the order of 10 and is probably due to the fact that the thennopile gives an average temperature difference at several vertical locations on the wall whereas the other method is
at one vertical location only
Since the thennopile produces an average temperature difference across the steel skin its
output is used to detennine the heat flux into the cabinet The refrigerator casing is being
used as a heat meter Thus the flux along the skin in the fresh food compartment on the
wall-side is
kmiddot ATwallffqwallff = m (44)
Ax
The load qwallJf is Eq (44) multiplied by the cross sectional area This area is the
thickness of the steel casing multiplied by the perimeter that is exposed to the room
ambient This perimeter varies for each of the two paths that comprise qwall and the two
paths that comprise qdoor The other cabinet loads are computed in a similar way and are
given in Table 42 The details of these values are given in Appendix E
Table 42 Experimental Determination of qwall and qdoor
Section Load W (BtuIhr)
qwallJf 28 (96)
qwallJz 21 (72)
qwall 49 (168)
qdoorff 33 (112)
qdoorJz 33
1112)
qdoor 66 (224)
20
45 Experimental Determination of qmulloff
The region that lies between the fresh food compartment and the freezer is called the
mullion The front portion of the mullion is covered by a thin steel face plate to provide a
suitable interface for the door seal magnets In this section the load due to heat conduction
along the mullion steel skin into the freezer and fresh food compartment is detennined
based on the experimental data
The heat transfer rate qmulloff is sum of two parts The first component is the heat
conduction along the steel plate into the fresh food compartment and the second is the
conduction into the freezer
qmulloff = qmulloffff + qmullofffz (45)
Figure 49 schematically illustrates paths of these two components
FREEZER
FRESH FOOD COMPARTMENT
Fig 49 Heat Flow Paths in Mullion
21
Ten 36 A WG type T thennocouples are mounted from top to bottom across the steel face
plate Figure 410 shows the cross section of the plate and the location and numbering of
the thennocouples
FREEZER
1bennocouplesSteel Face (5 mm spacing from
Plate bottom edge)
Freezer Gasket
Fresh Food Gasket
10 50
FRESH FOOD COMPARTMENT
1 in =254 mm
Fig 410 Mullion Face Plate Cross Section
Data are gathered from the ten thennocouples when the unit is shut off and allowed to drift
to a quasi-steady ambient temperature A total of five runs were perfonned Figure 411 is
a sample plot of the quasi-steady temperature profile All other plots are contained in
AppendixE
22
116
Run 1 I 115 ICcIIIII114 iii t ~mull~ =12~7 - 00~654xa
~ 113
rrfIIJ~~If112i 5 )mullfz 1= 1081~ + OOdl25X 111111 ~
11 oo+-t--t-iH-+-lo-shyiii i i Room Ambient = 2184 degc
109 middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1middot Fresh Ambient = 381 OC
108
1 10
I I I I I Freezer Ambient =-832 degc
2 3 4 5 6 7 8 9
TIC
Fig 411 Mullion Temperature Profile
The plot also shows two linear equations These represent linear fits to each side of the
peak temperature at TIC 7 The slopes (shown in degCmm) are used to detennine the heat
conduction to each compartment by eqs (46) and (47)
lmulloffff = km A (aT) (46)ax offff
qmul)offfz = km AIll) (47)ax offfz
The cross sectional area is the product of the face plate thickness (10 mm 0039 in) and
the length of the mullion (717 mm 2825 in) The average slopes from all five runs are
used to detennine qmulloffff and qroullofffz The results are given in Table 43
23
Table 43 Experimental Results from Mullion Analysis
Load W (Btuhr)
09qmullofUz (31)
07qmulloffff (24)
16qmuIlorr (55)
46 Experimental Determination of qmullon
In this section the load due to heat conduction along the mullion steel skin into the freezer
and fresh food compartment when an anti-sweat heater is on is experimentally determined
The test unit is equipped with an electric anti-sweat heater to eliminate condensation in the
mullion region The heater is installed on the back side of the plate and may be switched on
manually when needed It is a wire resistor type rated at 10 watts
The heat transfer rate qmullon is composed of two parts The first component is the heat
conduction along the steel plate into the fresh food compartment and the second is the
conduction into the freezer similar to ~ul1off
qmuIlon = ~ullonff + qmuIlonfz (48)
The location of the wire heater and the heat transfer paths are shown in Figure 412
24
FREEZER
qmullonfz
qmullonff
FRESH FOOD COMPARTMENT
Fig 412 Electric Heater Location
A series of tests are perfonned while the heater is on and the refrigerator is cycling
nonnally Three runs are done at each of three separate locations along the mullion
laterally (i) LEFT dermed as 180 mm (71 in) from the left-hand side of the unit (ii)
RIGHT 180 mm (71 in) from the right-hand side of the unit (iii) CENTER at center of
the mullion Figure 413 is a plot of the temperature profile across the face plate when the
heater is on for a specific test run The plots for all other runs are provided in Appendix E
The plot shows two profiles These represent the upper and lower limits as the unit cycles
The upper limit occurs just before the compressor turns on while the lower limit is at the
point in time just before the compressor shuts off At all times in between the profile
oscillates between the two limits maintaining nearly the same shape Once again a linear
fit is applied to the data on the fresh food side and the freezer side
25
30 iii imiddot iii i
29
28
27
Run 1
T mu
ill~~ 11 f = 26707 + 010776x Tmu11ff = 3128 - 00793x
Z +_ a 26~
I ~
middotmiddotmiddotbull-middotbullimiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotimiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotimiddotmiddotmiddotimiddotmiddot
24
25
e 23~ =H-T+H~i=i=
iimiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotimiddotmiddot T 11 ff = 27435 - 009504x 22 Tmullfz =21865 + 01l786x I m~ iii
21 -lmiddotmiddotmiddotmiddotmiddotmiddotmiddot-tmiddot Upper Limlt 0
20 middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotjmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotimiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddott 0 Lower Limit
19
0 1 2 3 4 5 6 7 8 9 10
TIC I
Fig 413 Mullion Temperature Profile With Heater On (Center)
Heat fluxes are computed identically to the method in Section 45 using the average slopes
from all nine runs The minimum value occurs just before to compressor turns on while
the maximum value occurs just before the compressor shuts off during normal cycling
The load is averaged over the cycle time which is approximately 50 for the test unit and
laboratory conditions The results are given in Table 44
Table 44 Experimental Results from Heater Analysis
Lower Profile Average W
(BtuIhr)
Upper Profile Average W
ffituhr)
qmullonfz 73
(249) 53
(181)
qmullonff 23 (78)
26 (89)
96 (32 7)
79 (270)
qmullon 88
300)
26
47 Determination of Qmisc
The load qoisc is comprised of three main parts The first is the load due to the evaporator
fan motor The fan that moves cool air in the cabinet also adds a thennalload Fans of this
type in use range from 8 - 16 watts The fan of our test unit is rated at 92 watts This
value must be integrated over the cycle time The cycle time for the unit is approximately
50 for the test conditions Thus the value of qfanave is 46 watts
The load qdefrostave is not determined experimentally Instead an estimate is obtained from
a similar study done by Turiel and Heydari (1988) This value is 5 watts which is an
average of the defrost heater input over the defrost cycle The defrost cycle can range from
10 - 12 hours of compressor run-time
The fmalload qcompave is detennined by measuring the cabinet surface temperature at the
region surrounding the compressor and computing the heat transfer locally The value is
found to be 2 watts Table 45 summarizes the results
Table 45 Miscellaneous Loads
Load W CBtuhr)
46 qfanave (15middotU
50 qdefrostave _07Ql
20 qcompave (68)
116 Qmisc (395)
27
s NUMERICAL SIMULATION
In this chapter a two-dimensional numerical model which is used to simulate the steadyshy
state heat transfer in the wall near the door seal is discussed The results from the model
include a computation of qwallff qwallfz and the complete temperature distribution across
the section The model is also used to estimate the additional cabinet load due to the
presence of an anti-sweat condenser tube embedded beneath the outer casing that runs
along the perimeter of the unit A separate model is presented which is used to simulate the
two-dimensional heat transfer across the door seal cross section The results are used to
determine qseal
51 Wall Model
A finite-difference technique is used to approximate the steady-state temperature
distribution in the wall section The technique is applied to solve the governing steady
two-dimensional heat conduction equation (assuming constant conductivity with no
generation)
(51)
Equation (52) is the basic fmite-difference representation of the conduction equation in a
homogeneous medium of constant conductivity with no heat generation (White 1988) In
Appendix F a complete list of all the model difference equations is provided
2(1+(3)Tij = (3Tij+l + Ti+lj+(3Tij-l + (3Ti-lj (52)
where (3 = (llxlly)2
28
Figure 51 is a sketch of the model representation of the refrigerator wall at the door seal region The dimensions shown are flexible parameters in the model The model allows for
slight changes in the geometry as well as changes in mesh size in both x and y directions
However the mesh size must remain uniform across the section
s5 s6
sl
Fig 51 Wall Heat Conduction Model Sketch
For each of N unknown nodal temperatures N simultaneous linear algebraic equations are obtained for N unknowns If N is large as is the case for this simulation an iterative
technique is preferred to solve the system ofequations A Fortran program has been
written to carry out the finite-difference iteration A copy of the code is given in Appendix
F A simple Guass-Seidel technique is employed for the differencing iteration At each
iteration an energy balance is done for the entire section In theory this balance should be
29
zero (heat entering) = (heat leaving) The iteration is continued until the difference
between heat entering and heat leaving is equal to 1 of the total heat entering the section
Table 51 defines the input parameters for the simulation
Table 51 Wall Simulation Input
Code Parameter Definition
To C (F) Exterior surrounding ambient temperature
Ti C (F) Interior ambient temperature
lan Wm-K (Btuhr-ft-F) Steel skin conductivity
kp Wm-K (Btuhr-ft-F) Plastic skin conductivity
kins Wm-K (Btuhr-ft-F) Wall insulation conductivity
heffo Wm2-K (Btuhr-ft2-F) Outside effective heat transfer coefficient
hefti Wm2-K (Btuhr-ft2-F) Inside effective heat transfer coefficient
dm mm (in) Steel skin thickness
dp mm (in) Plastic skin thickness
dx mm (in) Mesh size x direction
dy mm (in) Meshsizeydirection
sl mm (in) Wall width
s2 mm (in) Wall length
b mm (in) Effective Perimeter
s3 mm (in) Seal indentation
s4 mm (in) Seal width
s5 mm (in) Depth of steel skin into cabinet along seal boundary
s6 mm (in) Width of plastic skin along seal boundary
The model assumes that the boundary that lies along the door seal is adiabatic This allows
the separation of the wall section from the rest of the geometry in this region The seal and
door can then be treated separately later A simple calculation is done to validate this
assumption
30
Steel Skin (Refrigerator wall)
Seal (k = 02 Wm-K)
Fig 52 Non-adiabatic Door Seal
A 2 degC temperature difference AT is imposed across the seal This is a slight overshy
estimate based on the experimental data An estimate of the conductive heat flux is
determined from Eq (53)
ATqerror=k- (53) Ax
qrror =02 Wm-C o~Cm =20 Wm2
The heat flux ql for the fresh food compartment is determined in Appendix E to be 14418
Wm2 Therefore qerror represents approximately 13 of the total flux Hence this
term is neglected in this study
Two other possible sources of error are associated with the fmite-difference technique itself
(Ozisik 1980) The fIrSt is called truncation error and arises from the discretization of the
second-order derivative in the steady conduction equation The second is referred to as the
round-offerror which is due to the fact that numerical calculations are carried out only to a
finite number of decimal places Repeated solution with smaller increments shows that the
truncation error is negligible The precision of the energy balance is evidence that the
round-off errors are negligible
31
S2 Wall Simulation to Determine qwall
The finite-difference model is used to detennine the wall-side heat transfer along the steel
skin However more valuable information is yielded from the simulation The nodal
temperature distribution is detennined which gives insight into the direction and magnitude
of heat fluxes throughout the section The fresh food compartment and the freezer are both
simulated to detennine qwallff and qwallJz respectively Table 52 is the list of the values
used for the model input parameters for both cases
Table S2
Code Parameter
To C eF)
Ti C eF)
kIn Wm-K (Btuhr-ft-F)
kp Wm-K (Btuhr-ft-F)
kins Wm-K (Btulhr-ft-F)
heffo Wm2-K (Btuhr-ft2_F)
heffi Wm2-K (Btuhr-ft2-F)
dm mm (in)
dp mm (in)
dx mm (in)
dy mm (in)
sl mm (in)
s2 mm (in)
b mm (in)
s3 mm (in)
s4 mm (in)
s5 mm (in)
s6 mm (in)
Input Values
Fresh Food 210 (698) 40
(392) 540 (312) 015 (009) 0027 0015t 687 (121) 670 (118) 065
(0026) 25
(0098) 225
(0088) 25
(0098) 450
(1772) 2000 (7874) 2960
(11653) 225
(0088) 2025 (0797) 225
(0886) 2025 (0797)
32
Freezer 210 (698) -10
(140) 540middot (312) 015 (009) 0027 (0015) 687 (121) 641 (113) 065
(0026) 25
(0098) 28
(0088) 25
Jo098) 540
(2125) 2000 (7874) 1580
(6220) 28
(0110) 196
JO772) 224
(088t) 288
(1134)
The output from the simulation includes the entire nodal temperature field heat fluxes at
each node along the centerline heat fluxes from node to node along the steel skin beneath
the door seal and the value for qwallff and qwallcz These heat transfer values and the
nodal temperature distribution are listed in Appendix F
The quantities qwallff and qwallcz are determined by computing the heat fluxes from node to node along the centerline of the section subtracting the one-dimensional flux and then
multiplying by the cross sectional area for that node and summing to give the total heat
transfer rate The primary results are shown in Table 53
Table 53 Wall Simulation Results
Section
The temperature distributions are shown in the following two figures Figure 53 shows
the temperature contour for the fresh food results Figure 54 is the same plot for the
freezer results
Since the geometry of the refrigerator door is similar to that of the wall along the edges the
heat leakage to the food compartments along the door flange can be approximated as being
roughly the same as qwall This approximation of qdoor is a good means of estimating the
two prime contributors to the edge loss for various different refrigerators which may have
slightly different geometries as well as different material properties
33
i
3875
3625
TemplaquogtC)
-e
11111
20
18
16 3375
g 3125 14 -5 2875 ~ 122625 ~
2375~ 102125~
1875 8
1625
1375 6
1125
875 4
625
375
SteeVPlastic Liner Interface
Fig 53 Fresh Food Wall Temperature Distribution
34
i 4875
4625
4375
4125
3875
3625
3375 -
3125e g 2875
2625 ~ 2375 ~ 2125c (I)
1875 ~ 1625
1375
1125
875
625
375
125
Fig 54 Freezer Wall Temperature Distribution
Temp(OC)
20
15
10
5
0
-5
-10
35
53 Wall Edge Simulation to Determine qtube
The wall simulation is modified to include a constant temperature node placed beneath the
steel flange to represent the presence of an anti-sweat condenser tube The simulation is
perfonned for the specific conditions that are typical of the test unit as well as a range of
lateral tube locations For the test refrigerator the tube is located as shown in Figure 55
and is at 35degC (95 OJlt)
Outer Steel Skin
14625 mm 1
Inner Plastic Liner
Fig 55 Tube Location for Simulation
The quantity qtube is detennined by taking the fluxes along the vertical line to the left of
the tube subtracting the one-dimensional flux and then multiplying by the cross sectional
area for that node and summing to give the total heat transfer rate Again the fresh food
compartment and the freezer must be simulated separately to produce a total governed by
Eq (54)
(54)
Program output for the fresh food and freezer simulations is given in Appendix F Table
54 summarizes the results from the model
Table 54 Wall With Condenser Tube Simulation Results
Section Load W iBtubrl
qtubeff 46
(157)
qtubefz 28 (96)
qtube 74 (253)
qtube8ve (ave for 50 cycle time)
37 (126)
36
-I i c IJ
~
r 4875
4625
4375
4125
3875
3625
3375
3125
2875
2625
2375
2125
1875
1625
1375
1125
875
625
375
125
TempfC)
SteeVPlastic Liner Interface
35
30
25
20
15
10
5
Fig 56 Fresh Food Wall Temperature Distribution Including Warm Anti-sweat Tube
37
TempfC)4875
4625
4375
4125
3875
3625
3375 - 31258
2875g 2625fo 2375
3 2125 d vI 1875
~ 1625
1375
1125
875
625
375
125
SteeVPlastic Liner Interface
Fig 57 Freezer Wall Temperature Distribution Including Warm Anti-sweat Tube
38
40
30
20
10
0
-10
The heat fluxes at each node along the vertical line to the left of the tube are also computed
by the simulation This value quantifies the amount of heat that is moving toward the outer
boundary and is used to determine the percentage of heat entering the cabinet For the test
refrigerator this value is 18 for the fresh food compartment and 24 for the freezer
Several more simulation runs were done to find the effect of lateral placement of the tube on
the overall heat transfer and the percentage of heat entering Figure 58 and Figure 59
show the trends that are found
-~ a tUbe ~middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotlmiddotmiddotmiddot=middotmiddot=pmiddotmiddotmiddot=middot-1- =1
middot middot middoti middot middotmiddotmiddotmiddotmiddotmiddotmiddotmiddot bull middotmiddotmiddot i middotmiddotmiddotmiddot middotmiddot middotmiddot ~ middotmiddot
middotmiddotrmiddot-rmiddot 0 lwbeff middotlmiddotmiddot~middot Gmiddottmiddotmiddot9middotlmiddot
i i -0- lwbe i middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotimiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddot fz tmiddotEimiddotmiddot ~G- -~ -q- -
0 5 10 15 20 25 x(mm)
Fig 58 Load Due to Condenser Tube for Various Tube Placements
8
~ - 7
50
a 6
~ 5
~ en 4 ~
pound ~ 3
2
- 26
~ a 24
middots bO
pound 22c ~
~ 20
a = 18sect ~
16 0 5 10 15 20 25
x (mm)
Fig 59 Percentage of Heat Entering Cabinet for Various Tube Placements
39
54 Door Seal Simulation to Determine qseal
Another model is developed for the two-dimensional heat transfer through the door seal
This model is very similar to the one created for the wall section Once again a fIniteshy
difference technique is utilized to detennine the temperature distribution at steady-state
conditions Even though the cross sectional geometry of the seal is simplifIed to a square
with a hollow square with a centrally located cavity no closed-form solution can be
applied Therefore a simulation is needed
The fInite-difference representation of the two-dimensional steady Eq (55) using central
differencing is given by Ozisik (1980)
Ti-lj - 2Tij + Ti+lj + Tij-l - 2Tij + Tij+l = 0 (55) Ax2 Ay2
For this model a square mesh is applied reducing Eq (55) to
Ti-lj + Ti+lj + Tij-l + Tij+l - 4Tij = 0 (56)
x
Fig S10 Seal Simulation Mesh Layout
40
The nodes along the vertical surfaces at x=O and x=20 are subject to the convective
boundary conditions and governed by Eq (57) and Eq (58) respectively
2~xheffol 2~heffo2Ti+lj + Tij-l + Tij+l - (4 + k TiJ = - k To (57)
seal seal
2~heffffl 2~heffff2Ti-lj + Tij-l + TiJ+l - (4 + kseal Tij = - kseal Tff (58)
The nodes along the top and bottom outside surfaces are held at the prescribed temperature
profIles which are detennined from experimental data (see Section 41) The interior nodes
are subject to radiant e~change among themselves and conduction through what is assumed
to be stagnant air A closer look at the model of the hollow interior of the seal is shown in
Figure 511
Fig 511 Seal Cavity Mesh Details
Each interior node corresponds to a single gray surface with assumed emissivity of 09
Viewfactors for all surfaces are computed automatically before the iteration begins For
each iteration the effect of radiation within the enclosure is taken into account by updating
surface radiosities Jij Thus for nodes on interior surfaces an extra tenn is added to the
governing difference equation (Eb is the blackbody radiation)
41
~(J - Eb )1-pound IJ lj
A code written in Fortran is used to perfonn Guass-Seidel iteration of the difference
equations to compute the temperature distribution at mesh nodes (Code listing in Appendix
F) Once again convergence is based on an energy balance applied to the entire section
The iteration is continued until the difference between heat entering and heat leaving is
equal to 01 of the total heat entering the section Table 55 lists the input parameters
used in the model The fresh food compartment and the freezer compartment are simulated
separately
Table 55 Seal Simulation Input
Code Parameter Fresh Food Freezer
Number of nodes along outside edge 20 20
Number of nodes along inside edge 6 6 1 1Lx = fly mm (in) (0039) (0039)
210 210Outdoor ambient temperature degC (oF) (698) (698) 150 105Indoor local ambient temperature degC COF) 590J j509)
Outdoor heat transfer coefficient W m2-K 687 687 (121) (121)(Btuhr-ft2-F)
Indoor heat transfer coefficient Wm2-K 670 641 (118) (113)(Btuhr-ft2-F)
Gasket interior surface emissivity 09 09 03 03Gasket conductivity Wm-K (Btuhr-ft-F) (0173) (0173)
Wall-side Temperature Boundary 1905 - 1977x 1813 - 3475x Condition degC Door-side Temperature Boundary 1913 - 1384x 1852 - 2341x Condition degC
42
The load results are summarized in Table 56 below The program output is listed in
AppendixF
Table 56 Seal Simulation Results
Load W Section (BtuIhr)
10 Qsealff (34)
ljQsealfz (Sn
25qseal (85)
The steady-state temperature distribution is shown in the figures below Figure 512 is the
fresh food simulation and Figure 512 is the freezer simulation The direction of the heat
flow through the section is easily seen from these plots
43
Wall-side Boundary Temperature (C)
~~
I 20
195
i 19t 0
8 ~ 1859 -- ~
isis ~ ampJ gtshy 18 ~
11 ~ S ~ 175~
~ 17
165
x(mm)
Door-side Boundary
Fig 512 Seal Temperature Distribution (Fresh Food)
44
Wall-side Boundary Temperature (C)
Ii 19
185
18i f IQ 5 IQ
175-is-is I s 17j ~
5e 0C= 165
~ ~ 16
155
x(mm)
Door-side Boundary
Fig 513 Seal Temperature Distribution (Freezer)
45
6 DISCUSSION OF RESULTS
The heat transfer values detennined from the experimental analysis and the numerical
simulations are the various components that embody the cabinet load on the refrigerator It
is important to separate cabinet loads from system loads The system load can be thought
of as the total electrical energy consumption of the unit It has four basic components (i)
the compressor (ii) fans (iii) anti-sweat heaters and (iv) defrost heaters The first two
components the compressor and fans are the cost of removing heat from the cabinet This
amount of heat is equal to the cabinet load divided by the COP of the system The typical
energy consumption is shown schematically in Figure 61
System Load (Energy Consumption)
Defrost Heater (averaged over time
cycles every 10-12 hours of compressorrurt-time)
TuneCycle
Fig 61 Refrigerator System Load Graph
In a study done by Turiel and Heydari (1988) the compressor and fans accounted for 84
of the total system load for an 180 cubic foot top-mounted refrigerator Staley (1992)
found this value to be 86 for a similar unit Both of these studies used system analysis to
determine these numbers The energy consumption of the components were monitored
during operation The energy consumption of our test refrigerator can be determined in a
reverse manner from the cabinet load data If a COP of 1 is assumed the test refrigerator
46
compressor and fans accounts for 86 of the energy consumption to cool the cabinet This
compares favorably with the fmdings of Turiel and Heydari (1988) and Staley (1992)
Figure 62 is a schematic of the cabinet loads One possible load that is not included in the
figure is the heat input associated with the defrost drain tube that runs through the back
wall However this term is probably small relative to the other contributors
Cabinet Load
qseal qdoor
qwall
qmullon
qdefrostave
Fig 62 Cabinet Loads Graph
All the loads are determined in this study from either experimental measurements
numerical simulations or both Most of the loads are quasi-steady that is they do not
fluctuate significantly over the cycle time of the refrigerator There are four loads shown in
Figure 61 that are cyclical in nature The three loads that appear only while the
compressor is running are qcomp qfarb and qtube Also the refrigerator is subjected to a
load every time ice build-up is removed by the defrost heaters This load is averaged over
its own cycle time and shown in the graph as qdefrostave
47
61 Comparison of Simulation Results with Experimental nata
The majority of the cabinet loads are detennined from experimental data with the exception
of qseal and qtube The wall and door flange loads aremiddot also found from the numerical
simulation (see Chapter 5) The two-dimensional model detennines the wall-side heat
transfer along the steel skin into the food compartments No model is available to directly
detennine the heat transfer on the door-side However since the flange geometry on the
door-side is similar to the wall the value for qwall is considered to be a good estimate for
qdoor Table 61 gives these values determined from experimental measurements and the
simulation
Table 61 Comparison of Simulation and Experimental Values for qwall and qdoor
Experimental Result W Simulation Result W (BtuIhr) (BtuIhr)
qwallff 28 (96)
28 (96)
qwallz 21 (72)
27 (92)
qwall 49 (168)
55 (188)
ldoorff 33
(112) 28 (96)
qdoorfz 33
(112) 27 (92)
qdoor 66 (224)
55 (188)
The model predicts qwall to within 57 of the experimental value The agreement of the
estimate of qdoor with the experimental value is within 90
Some of the shortcomings in the model used in this investigation are
(i) Only the wall is modeled Ideally the entire region should be considered including the
door and seal (see Figure 11)
(ii) The flange geometry is simplified The steel casing skin in the flange region may bend
in more complex ways Also the plastic liner varies in thickness near the door seal
(iii) The mesh must be unifonn There is no means to vary how fme the mesh can be The
ideal situation would be to have a fine mesh near the edges and a course mesh far from the
seal
48
62 Mullion Analysis
The single largest edg~ load is found in the mullion section (329 of qedge and 94 of
qtol) This load is due to the electric anti-sweat heater installed on the backside of the face
plate The heater is rated at 10 watts and approximately 88 of that input enters the
interior of the cabinet as a thennalload This is probably due to the small surface area
exposed to the room and the low amount of convective heat transfer in the channel between
the fresh food and freezer doors With the heater on 88 watts is measured enter the food
chambers With the heater off only 16 watts enters the interior The addition of the
heater increases the mullion load 55 times Generally it is not necessary to use the
mullion heater at all times However for the test environment the heater nearly all the time
to eliminate sweating under the laboratory conditions
63 Seal Analysis
The heat conduction directly through the seal accounts for the smallest portion of the edge
loss (94 ofqedge and 27 of qtol) The numerical model to detennine these values uses
a simplified representation of the complex cross sectional geometry of an actual door seal
The various air pockets are reduced to a single hollow void There is no experimental data
to verify the model However the numbers and trends resulting from the simulation are
reasonable
64 Anti-sweat Condenser Tube Analysis
Thennocouple drag tests were perfonned to give insight into the nature of the temperature
profIles at the wall steel flange with the presence of an anti-sweat condenser tube The wall
heat transfer simulation model was modified to include the effect of this tube The heat
conduction to the interior increased by 76 at the wall flange region The amount of
additional loading due to the tube depends on several parameters location of the tube
temperature of the circulating refrigerant and local wall geometry Although the model is
flexible enough to handle vari01~S temperatures and limited geometrical changes only the
influence of tube position was investigated As the tube is moved towards the interior the
load increases For the test refrigerator about 20 of the heat flow was directed to the
interior compartments primarily along the steel skin
49
6S Overall Cabinet Load
The overall cabinet load is defined as a sum of three parts
(61)
The edge load is
qedge = qwall + qdoor + Qseal + Qrnullon + qtubeave (62)
where
qwall
qtubeave
heat input due to the conduction along the wall steel flange
heat input due to the conduction along the door steel flange
heat conduction directly through the door seal
heat input due to conduction in the mullion region with the additional input from anti-sweat heater
heat input due to cabinet anti-sweat condenser tube averaged over the cycle time
heat input due to cabinet anti-sweat condenser tube
qmulloff heat input due to conduction in the mullion region electric heater off
The terms of Qrnisc are defined as
qmisc = qfanave + qdefrostave + qcompave (63)
where
qfanave heat input from the evaporator fan averaged over the cycle time
qdefrostave heat input from the defrost heaters averaged over defrost cycle time
qcompave heat input from elevated exterior walls near the running compressor
Table 62 presents the overall cabinet load analysis results
50
Table 62 Overall Cabinet Loads
Load W Load Btuhr Total
qlD 550 1876 591
qedge 265 903 285
Qwall 49155 167 188 53
Qdoor 66155 2251 188 71
Qseal 25 85 27
Qmullon 88 300 94
Qtubl ngt 37 126 40
qmisc 116 395 124
Qfanave 46 157 49
Qdefrost ave 50 170 54
qcomoave 20 68 21
qtot 931 3174 100
Simulation Results
All loads are detennined experimentally with the exception oflsea1 and qtubeave The
values for qwall and qdoor are detennined from both experimental data and numerical
simulations Edge loss per unit length along fresh food perimeter is 29 Wm (30 Btuhrshy
ft) the loss per unit length along the freezer perimeter is 44 Wm (46 Btuhr-ft) and the
loss along the mullion section is 123 Wm (128 Btuhr-ft) with the heater on and 22 Wm
(23 Btuhr-ft) with anti-sweat heater off
The largest single load is the one-dimensional conduction through the walls and doors
The edge load comprises 285 of the total a significant portion The largest edge load is
due to the electric anti-sweat heater that is installed in the mullion section The smallest
edge load is due to the heat conduction through the fresh food and freezer door seals The
losses at the wall-side and door-side flange regions account for 53 and 71 of the total
load respectively These could be considered together since the pathway of heat transfer is
very similar If that were the case the sum of qwall and qdoor would be the second largest
contributor to the overall cabinet load The influence of an anti-sweat condenser tube is
reflected in the value of qtubeave Although this additional load is larger than qwall it must
be integrated over the refrigeration cycle timewhich is 50 of the cycle time for the test
unit The tube boosts the heat transfer along the wall flange by 76
51
To round out the cabinet load three miscellaneous loads are considered The evaporator
fan motor produces a heat load within the cabinet which is considered to be equal to the
power rating of the fan The automatic defrost feature is another thermal load that is
cyclical appearing about every ten to twelve hours of compressor runtime The fmalload
is due to the elevated exterior skin temperature near the compressor when it is running All
three of these loads are averaged over their cycle times for comparison with other quasishy
steady loads As a total qmisc represents 124 of the overall cabinet load
Opportunities to decrease the one-dimensionalload are available The emphasis has been to
develop super-insulations to be installed in the refrigerators Some being considered are
vacuum panels aerogels and vacuum packed powder insulations The disadvantages of
this improvement lies within the need to develop a cost-effective technique for fabricating
and installing such technologies compatible with high-volume manufacturing Also edge
losses and panel connection losses must be minimized due to the difficulty in making a
panel the size of refrigerator interiors Reliability of the seal and perfonnance of the outer
envelope need to be ensured over a long period of time ie the expected life of the
product
The possibilities of reducing the loads along the edge of the refrigerator aperture are
somewhat less apparent One method of reducing quasi-steady heat conduction along wall
and door flanges is to raise the inside cabinet wall temperature by minimizing interior film
surface heat transfer coefficients This could be accomplished by the use of low-emissivity
surfaces on the interior walls or on sections nearest the edges The need for an anti-sweat
device for the perimeter is also eliminated supplying a two-fold savings by reducing the
cabinet ioad and the system energy consumption The need for an electric mullion heater
might also be done away with by the same means The drawback again would be to make
such modifications acceptable and cost-effective for manufacture
The remaining miscellaneous loads provide some chance for improvement If the
efficiency of the fans is increased the energy use of the refrigerator can be reduced The
option of moving the fan motor outside the cabinet leads to other problems The motor
shaft must pierce the wall providing another path for heat leakage Also frost built-up on
the shaft would be a costly and difficult problem to eliminate If the compressor and
condenser were located near the top of the refrigerator they can operate more efficiently
Heat can be more readily convected away eliminating the need for the condenser fan
(Turiel and Heydari 1988) Frost fonnation in the freezer varies significantly depending
52
on the ambient conditions and the freezer usage The defrost cycle could be made more
energy efficient with the addition of adaptive controls All of these improvements would
require redesign of the product and the manufacturing process This is a very expensive
alternative which would need to be justified by the associated energy savings
53
7 SUMMARY OF CONCLUSIONS
The following is a list of the important findings produced from this study
(i) The edge loading accounts for a significant portion of the total cabinet load For the
test unit used in this study an 18 cubic foot top-mount refrigerator this load was
approximately 30 of the total load The load includes losses along the wall and door
flanges conduction through the door seal mullion loading with an electric anti-sweat
heater on and additional thennal input from an anti-sweat perimeter condenser tube
(ii) The presence of an electric anti-sweat mullion heater boosts the mullion loading by
a factor of approximately 5
(iii) The presence of an anti-sweat condenser tube around the perimeter of the refrigerator
increases the wall flange load by approximately 75
(iv) The presence of the door air damt reduces the temperature difference across the door
seal to 35 of the temperature difference between the interior and exterior
environments
(v) The hypothetical elimination of the additional load due to the electric anti-sweat
mullion heater reduces the edge loading to approximately 22 of the total cabinet
load
(vi) The hypothetical elimination of the load due to the anti-sweat condenser tube reduces
the edge loading to approximately 25 of the total cabinet load Ifboth anti-sweat
devices were not needed the edge loading would be further reduced to only 17 of
the total
(vii) During the course of this investigation it was concluded that the experimental and
numerical methods developed are applicable to most refrigeratorfreezers that are
produced today
t The portion of the door liner that extends into the cabinet along the wall
54
REFERENCES
Braswell A 1988 Impact of CFC Regulations on the Air Conditioning and Refrigeration Industry International Jow-nal ofRefrigeration Vol 11 No6 p 385
Cabot Corporation 1987 CAB-O-SIL Fumed Silica Properties and Functions Tuscola n pp 12-15
Clausing A M 1983 Natural Convection Correlations for Vertical Surfaces Including Influences of Variable Properties ASME Jow-nal ofHeat Transfer Vol 105 No 1 pp 138-143
Incropera FP and Dewitt DP 1985 Fundamentals ofHeat and Mass Transfer Second Edition John Wiley and Sons New York
Ingersoll LR Zobel OJ and Ingersoll AC 1954 Heat Conduction with Engineering and Geological Applications McGraw-Hill Book Company New York
Little AD Inc 1982 Refrigerator and Freezer Computer Model Users Guide Cambridge Massachusettes
Micropore International Ltd Microtherm Thermal Insulation Worcestershire England Section 1
Nix GH Lowery GW Vachon RI and Tanger GE 1967 Direct Determination of Thermal Diffusivity and Conductivity with a Refined Line-Source Technique Progress in Astronautics and Aeronautics (Vol 20) Thermophysics ofSpacecraft an Planetary Bodies Academic Press New York pp 865-878
Nix GH Vachon RI Lowery GW and McCurry TA 1968 The Line-Source Method Procedure and Iterative Scheme for Combined Determination of Conductivity and Diffusivity Thermal Conductivity Proceeding of8th Conference
Ozisik MN 1980 Heat Conduction Wiley-Interscience Publishing New York pp 486-487
Staley D 1992 Personal Communication Graduate Research Assistant University of Illinois Urbana
Turiel I Heydari A 1988 Analysis of Design Options to Improve the Efficiency of Refrigerator-Freezers and Freezers ASH RAE Transactions Vol 94 Part 2
Van der Held EFM and Van Drunen FG 1949 Physika Vol 15 No 10 p 865
White PM 1988 Heat and Mass TranSer Addison-Wesley Publishing Reading Mass pp 145-160
55
APPENDIX A FUMED SILICA INVESTIGATION
A ~ 1 Introduction
Fumed silica is a micro-porous powder comprised of submicron particles of amorphous
silica bonded together in a cellular structure Several grades of silica are available offering
a selection ofdifferent grain sizes and chemical treatments Fumed silica is commonly used
to provide thickening thixotropy suspension and other related properties in liquid
systems In dry systems it is used to promote free flow frictionizing and anti-blocking
properties Thus it is a versatile additive in materials such as inks coatings adhesives~
and silicon rubber (Cabot Corporation 1987)
The thermal insulating properties of this material have been somewhat less widely applied
however fumed silica as an insulation displays some interesting properties Fumed silica
insulations are commercially available and have become a more popular material for certain
specific applications In this section the results of an investigation of the thermal
properties of one type of fumed silica is presented
A2 Thermal Properties
As an insulator fumed silica uses the microporous principle to reduce thermal conduction
to the theoretically lowest possible levels (Micropore International Ltd 1988) Most
conventional insulations rely upon voids normally occupied bj alt aS the meanS ot
minimizing heat transfer through the material Therefore it is important to maintain these
voids for maximum insulation Fumed silica is comprised of tiny spheres with diameters
of the same order of magnitude as the mean free path of the molecules in the air
Therefore when these spheres are packed closely together gaseous conduction and
convection are minimized The cell size is sufficiently small to keep convective currents
from forming and to trap gas molecules to rebound elastically thereby not imparting their
energy to slower moving molecules In addition solid conduction is minimized by the fact
that silica is a material with intrinsically low thermal conductivity These unique properties
make fumed silica an attraCtive alternative to conventional insulations
56
A3 Experimental Method
Thennal conductivity and thennal diffusivity are the properties detennined from our
experimental study Many methods exist for establishing the thennal properties of a given
substance Both steady-state and transient procedures are available The hot-wire method
is a the transient procedure used in this study
The practical form of the hot-wire method is given by Van derHeldand Van Dronen
(1949) who used it to detennine conductivities of liquids Nix et al (1967) elaborated to
give a method for the simultaneous detennination of both thennal conductivity and thennal
diffusivity Therefore it is possible to detennine both conductivity and diffusivity by
passing a known amount ofcmrent through a heater wire embedded in the test material and
recording the temperature at a point on the wire and at a fixed point from the wire over the
period of the test From the temperature history of the point contiguous to the hot-wire the
conductivity can be detennined directly From the temperature history of the point at a
fixed distance from the hot-wire the diffusivity may be computed Both procedures are
outlined in the following section
A4 Theory
The temperature at any point in an infinite solid containing a line heat source of constantshy
rate is a function of the position time from initiation the thennal conductivity of the
material and the magnitude of the source This is shown mathematically by Ingersoll et aI
(1954) The cylindrical temperature field is expressed as
T=~l- exp-x2) dx (Al)21tk x
II
In series fonn
(A2)T=~[-amp-lnp+L-L+L_ ]21tk 2 21 4middot2 63
57
where
q = Heat input per unit length of wire [W1m]
k = Thennal conductivity of the material [Wm-K]
a = Thennal diffusivity of the material [m2s]
t = Elapsed time from heat liberation [s]
r = Radial distance from line-source [m]
Ce = Eulers constant (05772157 )
The temperature change between two times tl and t2 is accurate to better than one percent if
the value of ~ is less than 016 for a point very close to the line-source
(A3)
Equation (A3) is used in this case to detennine the thennal conductivity since the
diffusivity a and the radial distance T no longer appear in the relation Therefore
knowing the temperature at two different times during the test gives the conductivity
directly given that the value of ~ remains small This is achieved by choosing a point very
near if not contiguous to the hot-wire itself In our study a graphical method is used to
detennine the conductivity If the temperature versus the natural logarithm of the time is
plotted a straight line should be seen whose slope is equal to q4nk
Once the conductivity of the material is detennined the diffusivity can be found by the
method proposed by Nix et aI (1968) The temperature at a fixed and known distance
from the hot-wire must be monitored over the time period of the test Now since ~ gt 016
the diffusivity does not drop out of Equation (A2) Rewriting Equation (A3) as
(A4)
where
~2 ~4 ~6 ]r(~)= [ -~-ln~+---+-- (A5) 2 211 4middot2 6middot3
58
therefore (A6)
Using the temperature at the fixed location as an input Equation (A6) can be solved iteratively by means of Newton-Raphson technique to find the parameter ~ and thereby
yielding the thermal diffusivity a
AS Test Apparatus
Figure A1 is a sketch of the test apparatus used to collect thermal property data This
device provides a wide range of silica densities for packed tests Each half of the apparatus
is packed separately to the same density and then pressed together sandwiching the heater
wirethermocouple assembly between them
Remove bottom plate and press together with right half
Insert heater wirethermocouple assembl)
Remove bottom plate and press together with left half
Compact both halves to same density
Fig AI Fumed Silica Test Apparatus
Prior to loading the unpacked silica into the test cylinders the mass is carefully recorded
Each test cylinder has graduated marks to allow the volume of the sample to be computed
The density is then computed from the measured mass and volume At higher densities it
59
is sometimes necessary to load and compact several times Figure A2 is a schematic of the
heater wirethermocouple assembly and the entire test facility
Switch
Ammeter
Power Source
Cylindrical Test Section
Thermocouple for Conductivity
Data Acquisition System
Thermocouple for Diffusivity
Fig A2 Fumed Silica Test Facility Schematic
The heater wire used for all tests is 30 A WG nichrome wire with a nominal resistance of 2214 Wm Both thermocouples are type T 36 A WG Once the test sample is in place
the switch is closed allowing cUITent to pass through the heater wire The heat input per
unit length of the wire is determined from
(A7)
where q = Heat input per unit length of wire [Wm]
I = The input cUITent [Amps]
R = Heater wire resistance per unit length [Wm]
60
Knowing the heat input per unit length the temperature contiguous to the heater wire and
the temperature at a fixed distance from the heater wire over the duration of the test eqs
(A3) and (A6) can be solved This yields the conductivity and diffusivity respectively
A6 Results
All results presented in this section are from tests petfonned with a material sample donated
by Cabot Corporations Cab-O-Sil Division The silica is an untreated sample EH-5 with
a bulk density of 25 Ibsft3 and a nominal particle diameter of 70 angstroms Several tests
are petfonned at various densities The thermal conductivity is determined graphically as described above while the diffusivity is determined using a Fortran code to pe~orm the
Newton-Raphson iteration also outlined in Section A4
A total of seven different bulk densities are tested Each test consists of three runs at three
different power levels The temperature history is recorded for both thermocouples
Figure A3 is a plot of the temperature for the duration of a typical test for unpacked silica
70~--~----+----r----~-----~----+----r
10001
middot middot middot o 05 Ampsmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddot o 04 Ampsi ~ i
I i I I i oo~ct 60 IIJatr-T50
1 LL~40
1 ~ 1 010 1 ltgtom
JPi i30 i 0I1 o 03 Amps 1 I I
20~--~----+----r----~-----~----+----r
-10 o 10 20 30 40 50 60 70 Time (sec)
Fig A3 Time vs Temperature for Unpacked Run
61
To graphically detennine the thennal conductivity the temperatme data must be plotted
against the natural logarithm of time Figure A4 gives this plot along with the equations
that represent linear curve-fits to the straight portion of each curve
70~----~--------+------+--------~----~----~--------+-----~
60 ~ =l-LL-~--o T ~ 86839 ~ 1376 ~(t) I
50 ---f--H-deg--tfjtshy ~ T =11108 + 97346 m(t)
40 IT_oroJ~-
30 middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotImiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotsectmiddotmiddotmiddotmiddotmiddotImiddotmiddotmiddotmiddotmiddotmiddotmiddot~middotmiddotmiddotmiddot109~~Q9 T= 18431~ + 493 ~(t) 0
~ e i i i
20~----~--------+------+--------~---------~~----+------r
05 1 15 2 25 3 35 4 45 In (time)
Fig A4 Natural Log Time vs Temperature for Unpacked Run
All three curves should yield the same conductivity for the sample The conductivity is
detennined from the following relation
k= 12R (A8)4n(slope)
Table AI gives the average conductivity for each density level This is the average for the
three input cmrents used These results are also shown graphically in Figure A5
62
Table AI A verage Fumed Silica Conductivity for Various Bulk Densities
est
1
2
3
4
5
6
7
0024
0023
0022 -~ ct 0021
~ e 002
~
0019
0018
0017
i
~i
I I I I Imiddotmiddotmiddot_middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotimiddot_middotmiddot middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotimiddot-middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot
1i111
~ ~ iii
_I_1_1_1
I I I I I middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot middotmiddotmiddotmiddotmiddotmiddotmiddotfmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddot -r-t-o-rldegoo---shy
25 3 35 4 45 5 55
Density (lbsff)
Fig AS Conductivity vs Bulk Density
From the temperature data collected from the second thennocouple the thennal diffusivity
is computed (see Section A4) This thennocouple lies 3 mm (0118 in) from the heater
63
wire The output from the diffusivity iteration is provided in Table A2 A graphical
representation is given in Figure A6
Table A2 Average Fumed Silica Diffusivity for Various Bulk Densities
Test
Average Diffusivity m2s (ft2Jhr)
1 210 x 10-7 (000813)
2 166 x 10-7 (000643)
3 159 x 10-7 (000616)
4 155 x 10-7 (000600)
5 153 x 10-7 (000592)
6 No Data Available
7 151 x 10-7 (000585)
00085 -+----+-----f----+----+----+--_+_
I
middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1 ~0008
I I I I ~
I middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotfmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot Tmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot ~ 00075
~-shyf i ~ ~ ~ i ++middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotfmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot0007 i iii
~ rn ~ ~ i i~
(jj bullbullbullbullbullbull1bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullJLbullbullbullbullbullbullbullbullbullbullj ~ 00065o ~ middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot0006
I I I 00055 -+----+-----f----+----+----f--_+_
25 3 35 4 45 5 55
Density (lbsff)
Fig AS Diffusivity vs Bulk Density
64
A7 Conclusions
The primary conclusion from this experimental study is the fact that the thennal insulating
properties of fumed silica powder increase as the bulk density of the material increases
Although this study presents a limited range of density values the trends that were
expected are seen to be true The conductivity values are expected to reach and even
surpass those of CFC-blown foams that are used in household refrigerators Further
testing is needed to provide data that supports this expectation In addition testing in this
study was strictly limited to a single variety of silica This particular type of silica is not
necessarily the best candidate for thermal insulation applications Silica powders are by
nature hydroscopic This affinity for water has adverse effects on its thermal insulating
properties However silica powders are now produced with a special treatment which
transforms the material into a hydrophobic material Therefore if these new materials
maintain the thermal properties and density trends of the hydroscopic type they become
even more preferred insulators Once again data needs to be obtained to support this
notion Fumed silica offers a competitive alternative to the existing CFC-blown foams
without the obvious environmental drawbacks It is completely inert recyclable and
reusable It also competes well when comparing cost values CFC-blown foams are
between 003 - 007 $ft2_R-Value whereas fumed silica powder are between 005 -025
$ft2-R-Value The discrepancies are close enough to merit true consideration
AS Thermal Diffusivity Newton-Raphson Iteration Source Code
program difsivty implicit none double precision condqtime(lOO)temp(lOO)guessradiusalpha
+ dif(lOO)sumavedifgcurrentmasslengthpi + density integer nikrun OPEN (2file=Oiffusivityoutlposition=rewind) OPEN (3file=Oiffusivityinposition=rewind) OPEN (4file=Oiffusivityout2position=rewind)
print Enter input current in amps readcurrent printEnter calculated conductivity in Wm K readcond print Enter thermocouple distance in meters readradius print Enter mass of sample in grams readmass print Enter compacted length of sample in em readlength print Enter number of timetemperature data points
65
c
readn 5 print enter initial quess for beta
readquess c
pi=31415927 q=currentcurrent2214 density=(mass1000)laquopi4)(003844)(lenqth100raquo
c c check to see if converqence will occur c print Enter data point l c print (time and temp with a blank separatinq the two) c readtime(1)temp(1) c call diffus(condqtime(1)temp(1)quessradiusalphaq) c printinitial q=q c if (abs(q) qt 05) then c qoto5 c endif c
do 10 i=1n read(3) time(i)temp(i)
10 continue c
print print Input Current= current print write(2) Input Current= current write (2 )
c sum=OO do 20 k=1n call diffus(condqtime(k)temp(k)quessradiusalphaq) print Diffusivity for data pointk =alpha write(2) Diffusivity for data pointk =alpha write(4) alpha dif(k)=alpha sum=sum+dif(k)
20 continue c
avedif=sumn c
print print print INPUT print Conductivity=cond Wm K print Heater Input=q Wm print Thermocouple Distance=radius m print- print OUTPUT print Sample Density=density kqm3 print Averaqe Diffusivity=avedifmiddot m2s
c write(2) write(2) INPUT write(2) Conductivity=cond Wm K write(2) Heater Input=q Wm write(2) Thermocouple Distance=radius m write (2 ) write(2) OUTPUT write(2) Sample Density=density kqm3 write(2) Averaqe Diffusivity=avedif m2s
c c
pause stop
66
end
subroutine diffus(condqtimetempguessradiusalphag) implicit none double precision condqtimetempbeta(100)radius
+ f1f2f1pf2ptempf2tempf2pggppialphaCe + signfactol integer jkmn
c Ce=5772157 pi=31415927 beta (1) =guess tol=l j=l
c c begin Newton-Raphson iteration to find beta and ultimately alpha c
while (tol gt 0001) c print betaj =beta(j)
f1=-Ce20 - log(beta(j)) flp=-l Obeta (j) f2=00 f2p=00
c c start loop to compute the summations for f2 and f2 prime
do 10 k=2162 m=k2
c this loop gives the factorial for the kth term fac=10 do 5 n=lm
fac=facn 5 continue
sign=(-1)laquok+2)2) tempf2=laquobeta(j)k)sign)(kfac) tempf2p=laquobeta(j)(k-1))sign)fac f2=f2+tempf2 f2p=f2p+tempf2p
10 continue
c c compute the value of G and G which are both functions of beta c these will be used to update beta in the Newton-Raphson iteration c where beta(n+1)= beta(n)- GG
g=laquo20picondtemp)q)-(f1+f2) gp=- (flp+f2p)
c print g=g c here we check to see if the convergence criterion suggested c by Nix is met for the initial beta chosen if not we must jump out of loop c if (j eq 1) then c if (abs(g) qt 05) then c printconvergence not satisfied c printtry a s~aller guess for beta c return c endif c endif c c update the value of beta and compute a tolerance value c that will be used to check for convergence
beta(j+1)=beta(j)-(ggp) tol=abs(beta(j+1)-beta(j))
67
j=j+1 c protect against infinite looping
if (j eq 100) then goto 101
endif repeat
c c if the iteration converges then compute the value for diffusivity
alpha=(10(40timeraquo(radiusbeta(jraquo2
c c
101 return
68
APPENDIX B ONE-DIMENSIONAL SIMULATION SOURCE CODE AND OUTPUT
B1 Source Code
CPROGRAM FrigWall--Steady-State Heat Conduction with Convective and CRadiative Heat Transfer from interior and exterior surfaces C Programmed by AM CLAUSING
LOGICAL SI DIMENSION RA(2)XNU(2)R(2)H(2)HR(2)TF(2)TW(2)DT(2) COMMON AXLWXLC(2)HC(2)T(2)XKWBETANMAXSIE(2)SIGMA
CDetermine- direction of output read and print input data NCASE=l
1 CALL DATAIN(NCASEIUOUT) NCASE=NCASE+1 QOLD=O TW(1)=T(1)+1(T(2)-T(1raquo TW(2)=T(2)-1(T(2)-T(1raquo
CCalculate wall resistance RW=XLWXKWA DO 3 N=lNMAX DO S J=12
CCalculate the radiative equivalent heat transfer coefficients HR(J)=SIGMAE(J)(T(J)2+TW(J)2)(T(J)+TW(Jraquo
C Calculate the film temperatures TF(J)=(T(J)+TW(Jraquo2
CCalculate the convective heat transfer coefficients CALL GASPT(lTF(J)RHOXMUXKCPGRBPRIER) DT(J)=ABS(TW(J)-T(Jraquo RA(J)=PRGRBXLC(J)3DT(J) IF(RA(J) LT1E9) THEN
XNU(J)=0S2RA(J)2S ELSE
XNU(J)=09RA(J) 3333 ENDIF H(J)=XNU(J)XKXLC(J) IF(HC(J) NE O) H(J)=HC(J)
CCalculate surface resistances R(J)=l(H(J)+HR(JraquoA
S CONTINUE CCalc~late total resistance heat flow rate and surface temperatures
RT=R(1)+R(2)+RW Q=(T(2)-T(1raquoRT TW(l)=T(l)+QR(l) TW(2)=T(2)-QR(2)
CCheck for convergence If solution has converged exit loop ERRQ=ABS(Q-QOLD)100Q QOLD=Q IF(ERRQLT OS) GOTO 7
3 CONTINUE 7 WRITE (IUOUT 101) Q ERRQ (H (J) HR (J) RA (J) XNU (J) TW (J) DT (J) R (J) RT
2 J=l2) 101 FORMAT( Q =F61 W10XERRQ =FS2 T12 hconvT22hradT33
2 RaT44NuTS2 TsurT62 DeltaTT72RRtotT10 [Wm2-KjT20 2 [Wm2-KjTS3 [KjT63 [Kj InsideF72F92E133F91 2 F101F91F113 OutsideF62F92E133F91F101F91F113) DO 9 J=l2 IF(HC(J) NE bull O) WRITE (IUOUT 103) J
9 CONTINUE 103 FORMAT( NOTE hconv(I1 ) was specified not calculated)
GOTO 1 END
69
C SUBROUTINE DATAIN(NCASEIUOUT) LOGICAL SI COMMON AXLWXLC(2)HC(2)T(2)XKWBETANMAXSIE(2)SIGMA DATA AXLWXKWXLCHCTENMAXSIGMA2990360245315 2 20277297 959510567E-8
CDefinition of NAM NAMELIST NAMAXLWXKWXLCHCETNMAXBETASI CHARACTER FNAME60CDATE9CTIME8 PARAMETER (IUIN=7)
CIF First Case Open Files Write Program Description and Date IF (NCASEEQ 1) THEN
WRITE (6 100) 100 FORMAT( TYPE NAME OF INPUT DATA FILE)
READ( (A) ) FNAME COpen input and output files
OPEN (7FILE=FNAME) REWIND 7
C OPEN (10FILE=Plots-FNAME) C WRITE(6122) Plots-FNAME C122 FORMAT( COMMA DELIMITED PLOTTING FILE IS A)
WRITE(6118) 118 FORMAT (T10 DIRECT OUTPUT TOT20 SCREENT36 Type 6
2 T20 OUTPUT FILET36 Type 8T20 PRINTERT36 Type 9) READ() IUOUT IF(IUOUTEQ8) THEN OPEN (8FILE=Answers-FNAME) WRITE(6120) Answers-FNAME
120 FORMAT( OUTPUT WILL BE WRITTEN IN FILE A) ENDIF CALL DATE(CDATE) CALL TIME(CTIME)
CWrite Program Description and Date WRITE(IUOUT102)CDATECTIME
102 FORMAT( Program FrigWallT60 Date A10 Version 8 August 1991T60 2 Time A9 Programmed by AMClausing) ENDIF
CRead and Write Input Data READ(IUINNAMEND=999) WRITE (IUOUT 104) NCASETXLCEXLWXKWA
104 FORMAT ( CASE NUMBER 12 2 Ambient Temperatures IK] InsideF616X OutsideF61 2 Characteristic Lengths 1m] InsideF626X OutsideF62 2 Surface Emissivities8X InsideF626XOutsideF62 Wall
Thickness 2 F63 mT27 ConductivityF63 Wm-K2x AreaF52 m2) RETURN
999 WRITE (IUOUT 199) 199 FORMAT ( ALL INPUT DATA HAS BEEN PROCESSED) 991 CLOSE(10)
IF(IUOUTEQ 8) CLOSE(8) STOP END
C SUBROUTINE GASPT(NGASTRHOXMUXKCPGRBPRIER)
C PROGRAMMED BY A M CLAUSING VERSION APRIL 1982 C PROPERTIES OF GASES IN SI UNITS(TGTO) OR ENGLISH UNITS(TLT O) C FUNCTIONAL REPRESENTATIONS USED ARE OF THE FORM Y=ATB C ARRAYS A AND B CONTAIN THE RESPECTIVE CONSTANTS C INPUT C NGAS - NGAS=l IS AIR NGAS=2 IS NITROGEN C T ---- ABSOLUTE TEMP (K) OR NEGATIVE OF ABSOLUTE TEMP (R) C OUTPUT C RHO -- DENSITY (KGM3) OR (LBMFT3)
70
C XMU -- VISCOSITY (KGM-S) OR (LBMFT-S) C XK --- THERMAL CONDUCTIVITY (WM-K) OR (BTUHR-FT-R) C CP --- SPECIFIC HEAT (JKG-K) OR (BTULBM-R) C GRB -- GBETAXNU2 (1M3-K) OR (1FT3-R) C PR --- PRANDTL NUMBER (DIMENSIONLESS) C IER -- ERROR PARAMETER C INFORMATIVE ERRORS C IER=l --- GAS NUMBER DOES NOT EXIST GAS IS ASSUMED TO BE AIR C IER=2 --- TEMPERATURE OUT OF RANGE OF PROPERTY SUBROUTINE C RESTRICTIONS C NGAS -- MUST BE l(AIR) OR 2 (NITROGEN) C T ----- T MUST LIE BETWEEN 150K AND 2100K FOR AIR AND BETWEEN C 83K AND 450K FOR NITROGEN RANGES ARE SPECIFIED WITH ARRAY R C
DIMENSION A(152)B(152)R(32) DATA A36411764E-61423E-399084178E20123 235064914E-62494E-329944985E195930 3 432491E-81239E-415534379E201137 4351618E-6221E-31031408E2084130 DATA B-1005814913800316-4639-09685 2 -999642981521962-4284023930 3 -10469389466-079-5102-0872 4 -10058058 834500239-4636-0265230 DATA R150400210083160450 IER=O IFlaquoNGASGTO) AND(NGASLT3raquo GO TO 1 IER=l NGAS=l
1 1=1 TP=T IF(TLT bullbull O) TP=-T18 IFlaquoTPLTR(lNGASraquo OR (TPGTR(3NGASraquo) IER=2 IF(TPGTR(2NGASraquoI=7 RHO=A(INGAS)TPB(INGAS) XMU=A(I+1NGAS)TPB(I+1NGAS) XK=A(I+2NGAS)TPB(I+2NGAS) CP=A(I+3NGAS)TPB(I+3NGAS) GRB=A(I+4NGAS)TPB(I+4NGAS) PR=A(I+5NGAS)TPB(I+5NGAS) IF(TGT O)RETURN RHO=RHO1602 XMU=XMUl 488 XK=XKl 731 CP=CP4187 GRB=GRB6357 RETURN END
B2 Output
Program FrigWal1 Version 8 August 1991 Programmed by AMClausing
Date Time
05-MAR-92 200227
CASE NUMBER 1 - Fresh Food Walls
Ambient Temperatures IK] Inside 2770 Outside 2940 Characteristic Lengths 1m] Inside 030 Outside 150 Surface Emissivities Inside 095 Outside 095
71
Wall Thickness 0045 m Conductivity 0027 Wm-K Area 242 m2
Q = 209 W ERRQ = 002
hconv [Wm2-K]
Inside 1 98 Outside 130
hrad [Wm2-K] 461 544
Ra
0488E+07 0459E+09
Nu
244 761
Tsur [K]
2783 2927
DeltaT [K] 13 13
RRtot
0077 0075
CASE NUMBER 2 - Fresh Food Door
Ambient Temperatures [K] Inside 2770 Outside 2940 Characteristic Lengths [m] Inside 030 Outside 150 Surface Emissivities Inside 095 Outside 095 Wall Thickness 0040 m Conductivity 0040 Wm-K Area 089 m2
Q = 117 W ERRQ = 001
hconv [Wm2-K]
Inside 218 Outside 144
hrad [Wm2-K] 463 542
Ra
0714E+07 0690E+09
Nu
269 843
Tsur [K]
2789 2921
DeltaT [K]
19 19
RRtot
0114 0113
CASE NUMBER 3 - Freezer Walls
Ambient Temperatures [K] Inside Characteristic Lengths [m] Inside Surface Emissivities Inside
2630 030 095
Wall Thickness 0056 m Conductivity 0027
Outside Outside Outside
2940 150 095
Wm-K Area 110 m2
Q = 14 3 W ERRQ = 003
hconv [Wm2-K]
Inside 226 Outside 143
hrad [Wm2-K] 397 542
Ra
0990E+07 0684E+09
Nu
292 841
Tsur [K]
2651 2921
DeltaT [K]
21 19
RRtot
0067 0061
CASE NUMBER 4 - Freezer Door
Ambient Temperatures [K] Inside 2630 Outside 2940 Characteristic Lengths [m] Inside 030 Outside 150 Surface Emissivities Inside 095 Outside 095 Wall Thickness 0040 m Conductivity 0040 Wm-K Area 034 m2
Q = 81 W ERRQ 002
hconv [Wm2-K]
Inside 259 Outside 1 64
hrad [Wm2-K] 400 538
Ra
0169E+08 0124E+10
Nu
333 967
Tsur [K]
2666 2906
DeltaT [K] 36 34
RRtot
0117 0110
72
__ ___
APPENDIX C TEST REFRIGERATOR DESCRIPTION
The test refrigerator is a White-Westinghouse model RT193MCWO 186 cubic foot
capacity top-mounted unit It is equipped with full automatic defrost The cycle time for
this unit is approximately 50 The unit also has two anti-sweat devices An electric
heater is located in the mullion region to prevent frosting between the freezer and the fresh
food compartments Also a condenser tube runs around the entire outside perimeter of the
unit embedded beneath the steel all flange Figure C1 illustrates these features
~1-- 0787 m (31)__
~ r_----------------------
1581 m
Fig CI Location of Anti-sweat Devices and Overall Dimensions of Test Refrigerator
73
Under test conditions the refrigerator and freezer are filled with milk containers full of
water These containers provide sufficient thennal mass to minimize temperature
fluctuations dming experimental runs Twenty gallons are present in the fresh food
compartment and 6 gallons are in the freezer
Figures C2 through C5 give the detailed dimensions of the fresh food compartment and
the freezer All dimensions are in millimeters and are obtained directly from the unit
Dimensions are estimated to be accurate to within plusmn 3 mm
697
762
1
305
717
Fig C2 Fresh Food Compartment Interior Dimensions
74
1127
Fig C3 Fresh Food Door
75
675
381
Fig C4 Freezer Interior Dimensions
432
Fig CS Freezer Door
76
APPENDIX D DATA ACQUISITION AND CONTROL SYSTEM
Corresponding with the construction of the experimental apparatus was the purchase and
assembly of a data acquisition and control system The system itself was designed to meet
the needs of a variety of experiments and is therefore a very flexible system
The system consists of six DC power supplies a data acquisition chassis a computer a
rack ofdigital relays and a variety of analog and digital inputs and outputs A data
acquisition and control software package orchestrates the interactions between these
components and regulates outgoing signals as well as providing data storage
External signals enter the system through a Keithley 500P data acquisition chassis These
signals consist of voltage and current measurements from the power supplies as well as
thermocouple voltages At present a total of ninety-six thermocouple inputs are available
with an optimal resolution of +0012 degrees C The addition of more thermocouple input
boards could expand the capability to 128 inputs Also special boards can be installed to
allow strain gauge thermistor digital or other standard data acquisition functions The
Keithley chassis can contain a total of nine interface boards and its l~bit AID conversion
allows for very high resolution
The six DC power supplies consist of two Hewlett Packard and four Sorensens with a
combined power of 7560 watts The Sorensens are rated at 0-150 volts at a maximum of
12 amps while the Hewlett Packards produce 0-60 volts at a maximum of 3 amps All of
the power supplies are computer-controlled however the Sorensens may be operated
manually ifdesired Voltage measurements from the power supplies are fed into the
Keithley acquisition chassis and are then routed to the computer A voltage from the
computer is buffered and fed into the control circuits of the power supplies This voltage
completes the loop and controls the output voltage of the power supplies The software is
responsible for reading the output voltage of the power supplies comparing it with the
intended setpoint and adjusting the control voltage as needed This arrangement allows the
user to vary the output voltage of the power supplies from within a program Computershy
controlled safety relays are in place to disconnect the power supplies should they stray too
far from the intended voltage setpoint Fig D1 displays the system
77
Thermocouple and Voltage Inputs
r
Computer Data Acquisition Chasis Intaface
00 Voltage and 1 r Current
Measurement
Computer
I I
Analog Control Signal
Digital Oulput Signals 5 6
Power Supply 4 Relay Rack
Power Supply 3 00000001 Power Supply 2
Buffered Analog100000001 Power Supply 1 Control Signal
1 2 3 4 5 6 - I
I00 00 )0 po po po
Ir Digital Outputs
Analog Outputs
Fig DI Data Acquisition and Control System
78
APPENDIX E EXPERIMENTAL RAW DATA AND PLOTS
E1 Temperature Profile Plots From Fixed Thermocouples
In this appendix the remaining tests for the fixed thennocouple testing presented in Section
41 are provided Figures E1 and E2 give the results from the fresh food compartment
and Figures E3 and E4 give the results from the freezer Notice the outdoor and interior
ambient temperatures are not the same as the two tests presented in Section 41
191
Run 2 ttl ~ i i
middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot
middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot-imiddotmiddot
TWall
middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotlmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot
-
Outdoor Ambient =210 degC Fresh Food Ambient =375 degC
-] _ Door ProfUe i -il- 0 Wall Profile
i 19
$-- - Tdo = 19078 - 001326x
l~l ~~i 189 i i a m
0 i -m-
i 188 middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot
187 ~ middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot 5 = 18989 - O02024x 1
F 186
~bullbullbullbullbullbullbullmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot185 i i
184 0 5 10 15 20 25
x (mm)
Fig E1 Steel Skin Temperature Plot for Fresh Food Compartment (Run 2)
79
191
19
189
a ~
i 188
187
5F
186
185
184 0
Run 3 I --D - Door Profile
middotmiddotmiddotmiddotmiddotmiddotmiddotmiddot-middotmiddotmiddotmiddot~middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotimiddotmiddot-middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddot 0 Wall Profile
i - i - - Tdo =19053 - 001384x or
=c-=r=-~-= 1 11=
~ n - 189S 001998 --t-shy-~~-
5 10 15 20 25
x (mm)
Fig E2 Steel Skin Temperature Plot for Fresh Food Compartment
186
184
182
- ~- 18
178
~ 176
174
172 0
(Run 3)
Run 2 l --0 - Door Profile
middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot~middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotdrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotf 0 Wall Profile - 1- - middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot--m
- - T =18544 - 002398x i - i door rb
~i
i bullbullbulli _ bull imiddot
~ I TWall =18182 - 003542x tmiddotmiddotmiddotmiddot middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotlmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot
~ n~l l
5 10 15 20 25
x (mm)
Fig E3 Steel Skin Temperature Plot for Freezer (Run 2)
80
--a 0
I5F
186
184
182
18
178
176
174
172
Run 3 I --0 - Door Profile
middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotCmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotl 0 ~a1l Profile
ttl __ OJ 1 1 middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotfmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotlmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot -shy - Td = 18411 - 002272x ibullbullbullbullbullbullbull-bullbullbullbullbullbullbullbullbulli
oor ~
rp bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbull bull 11_1
I I middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotimiddotmiddotmiddotmiddot middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotImiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot
~ _l
Outdoor Ambient =208 degc Freezer Ambient = -93 degc
0 5 10 15 20 25
x (mm)
Fig E4 Steel Skin Temperature Plot for Freezer (Run 3)
E2 Thermopile Data Reduction
The data from the thennopile tests consist of an output voltage (mV) measured with a
Keithley multimeter which has a resolution of 1 m V The procedure required to translate
this voltage into a temperature difference follows
1 Read the output voltage in millivolts
2 Detennine the average skin temperature from fixed thennocouple data
3 Use the reference table and the average skin temperature to determine the conversion factor in Vrc
4 Convert to temperature difference as follows
1T = ____o_utpu_t_vo_l_tag-e___
ofjunctions x conversion factor
81
Table EI Thermopile Raw Data
ffOutput fzOutput ff Ave Skin Temp fz Ave Skin Temp mV mV CC CC
Roo wall door wall door wall door wall door
1 0052 0048 0045 0050 189 191 177 183
2 0054 0052 0046 0048 187 189 176 182
3 0056 0053 0046 0051 186 188 175 181 ff Conv Factor fz Conv Factor ff AT fzAT
Ilvrc Ilvre CC CC
Roo wall door wall door wall door wall door
1 40165 40181 40067 40116 026 024 037 041
2 40148 40165 40058 40107 027 026 038 040
3 40140 40157 40050 40099 027 026 038 040
Average Temperature Difference 0267 0377 0253 0403
from Thermocouple Reference Tables Based on the IPTS-68 US Dept of Commerce
E3 Experimental Determination of qwall and qdoor Details
The four heat fluxes are calculated using
-k M (El)q - m Ax
For 05 carbon cold rolled steel km =540 Wm K (312 Btuhr-ft-OF) Also Ax = OOlm (039 in) for all computations
0267degC 2 qwallff = 54 Wm-K 001 m = 14418 Wm
_ 0377 degc _ 2 qwallfz - 54 Wm-K 001 m - 20358 Wm
0~3~ 2 qdoorff =54 Wm-K 001 m =13662 Wm
82
0403degC 2 qdoorfz = 54 Wm-K 001 m = 21762 Wm
Compute the heat transfer rate according to Equation (B2)
q =qA=qhP (B2)
Where A is the cross sectional area of the steel casing that is perpendicular to the direction
of heat flow The area is the product of the steel skin thickness b and the total perimeter of
the compartment opening which is exposed to the room environment P Perimeter
definitions
Pwallff = llm + 076m +llm = 296 m
roJ D Pwallfz =O4lm + 076m + O4lm =l58 m
I ] I ~I Pdoorf( = llm + 076m + llm + 076m = 372 m
Pdoorfz =076m + O4lm + 076m + 041m =234 m
83
qwallff =(14418 Wm2)(65e-4 m)(296 m) =277 W
qwallfz =(20358 Wm2)(65e-4 m)(158 m) =209 W
qdoorff =(13662 Wm2)(65e-4 m)(372 m) =330 W
qdoorfz =(21762 Wm2)(65e-4 m)(234 m) =331 W
E4 Temperature Profile Plots From Mullion Data (Heater oro
The following plots are from the remaining runs for the mullion analysis presented in
Section 45 All data is taken from the exact center of the mullion
131
13 middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot-tmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotjmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotlmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot9middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotlmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot6middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddot T 11 f =12383 + 0019929x iii mu z
129 ~ middotImiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot[middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddota ~
i 128 middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot4middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot-j-middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotfmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotfmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot
127e ~
126 ~~~=H~~-~=HmiddotrI~ ++~11 Room Ambient =2250 degC125
1 1 i Fresh Ambient =515 degC iii i i Freezer Ambient =-603 degC
124
1 10
Fig ES Mullion Temperature Profile Run 2 (Heater Off)
Run 2
2 3 4 5 6 7 8 9
TIC
84
146
145
a 144 ~
i 143
5 ~ 142
141
Run 3 9 0
---r-r--deg-r-ideg-t-9--rshyiii ltD T 11 ff = 15173 - OOI71x mu bull
middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotfmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotImiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot6middotmiddot
1Tmull~fz =14062 + J0158211x JLt 1
Q 1 1 1 middotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1-middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddoti-middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotimiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotoot-middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot-I-bullbullbull~bullbullbullbullbullbullbullbullbullbullbull
iii middotiiimiddot-j Room
1Am~t = 21~1 degC
iii i 1 Fresh Ambient = 563 degC 1 1 1 1 1 Freezer Ambient = -153 degC
14~---+--~----r---+---~---+--~----r---+-
1 2 3 4 5 6 7 8 9
TIC I
Fig E6 Mullion Temperature Profile Run 3 (Heater Off)
127
126
125 a ~
i 124
123 e ~
122
121
12
1
Fig E7
i i CD middotmiddotmiddotmiddot----middotmiddot-r--middot---middotmiddotmiddotmiddotmiddotmiddot-lmiddot--------middotmiddotmiddotmiddotl-middotmiddot---middotmiddotmiddotmiddot---r---middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1middotmiddotmiddotmiddotmiddot---middotmiddot---middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot-r----middot1__ _-
I I I T mulIff = 1321 - 001532x middotmiddotmiddotmiddot------middott--------------tmiddotmiddot----middot----middotmiddot-1------middotmiddotmiddotmiddotmiddotmiddot---jmiddot-----middotmiddotmiddotmiddotmiddotmiddotmiddotmiddot-lmiddotmiddotmiddot---middotmiddotmiddot-----tmiddotmiddotmiddotmiddotmiddot--middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddot-----middotmiddotmiddot6middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot
I cent I I I I -~~~~-ro-Tr-
r-middotmiddotmiddotmiddotrTTr-middotrmiddotrmiddotrmiddot middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddott middotmiddotmiddottmiddotmiddot1middotmiddotbullbullbullbull fmiddotbullbullbullbullbullbullbullmiddot-fbullbullbullbullbullbullbullmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot
II Room Ambil =21~3 degC iii i i Fresh Ambient =551 degc iii i i Freezer Ambient = -681 degC
2 3 4 5 6 7 8 9 10
TIC I
Mullion Temperature Profile Run 4 (Heater Off)
85
10
111
iii i i 11
Fttul5
T mu
=J=~[rr~tl=rI=109
a ~ 108 -t-t-t-i~FFl~i~~
+-0amp_- -+_bullbullbullbullbullbullbullbull+ - bullbullbull 107 11 f ~ 10325 + 0021893x 1 1 1 ji
5 bull Z iii
------~-~-----~---i --L--l ---_l__ ---L-----_shy106 ~
105 -t---i--+-+-+-middot++-I-shyL1LLL Room Ambient = 2177 C104 iii i i Fresh Ambient =448 degC
Freezer Ambient = -644 degC 103
1 2 3 4 5 6 7 8 9 10
TIC
Fig E8 Mullion Temperature Profile Run 5 (Heater Off)
86
34
33 1 1 1 1 1 1 1 1------I---------middotmiddot--+middotmiddotmiddotmiddot------middottmiddot-------middotmiddotmiddotmiddottmiddot----------middotmiddotmiddot---middot---middot----tmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot---middotmiddott--middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot(middotmiddotmiddotmiddotmiddot--
32 11 f =1 2859 ~ OI~X j
Till ff =133013 j - 007124x mu
31
a ~ 30
i 5 ~
29
28
27
26
Tmullfz = 26944 + 014842x
mu t-tr l
25 middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotjmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotjmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotlmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1middot ~ u~ ~it
24 lllti1 ~ i i ~ i
0 Lower Limit
23
0 1 2 3 4 5 6 7 8 9 10
ES Temperature Profile Plots From Mullion Data (Heater On)
The following are the remaining plots from the mullion heater analysis presented in Section
46
TIC I
Fig E9 Mullion Temperature Profile Run 2 (CenterHeater On)
Run 2
T muz
1
87
l----+
29
middotmiddotmiddotgtmiddotmiddoti middot 0 upper Limit 28 Run 1
I
middotmiddotI o
Tmullfz
T muo
LL~4cb 0 Lower Limit27
middot~+ImiddotmiddotmiddotImiddotmiddotmiddottr9middotdJmiddotmiddotmiddotmiddot 26
t T = 29465 008022xmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddot1middotmiddotmiddotmiddotTmiddotmiddotmiddotmiddot[middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1middot mullffa 25~
i 24 =24837+ 013186x middotlmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot+middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotimiddotmiddotmiddotmiddotmiddotmiddotmiddotlmiddotmiddotmiddotmiddotmiddotmiddot iii i i
i _ Jbullbullbullbullbullbullbullbullbullbullbullbullbulli l _l ii 23
e 22~ 21 +I~=tt=l=fit
L~LLL Tm~llff = 23856 005858x20 11 f = 1803 + 02243x z -rmiddotmiddotmiddotmiddot1middot middotmiddot middotmiddot 1middotmiddotmiddotmiddotmiddotTmiddotmiddot middot-rmiddot19
18
0 1 2 3 4 5 6 7 8 9 10
TIC
35
34
33
32
a ~ 31
I ~
30
29
28
27
26
25
24
Fig EI0
---bull---i----bullbullmiddotmiddotmiddotmiddot--~--------middotmiddot-+------ j bullbullbullbull ---bullbullbullbull -i--__---
T 11 f =30063 + OI~x 1 T i 134 196 i
0068 1 38
muz tmiddotmiddot Ilff=middot bull x ltP lt1gt mu
=t=H=t+t=R=t= F-6~I-i~E
Tmullfz = 28103 + 014486x 1middot++middot1middot1
middotmiddotmiddot--middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotimiddotmiddotmiddotmiddotmiddotmiddotmiddot-middotmiddotmiddotmiddotmiddot+middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotbullbullmiddotmiddotmiddot-middotmiddotimiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot~middotmiddot
111111 0 Upper Limit iii iii 0 Lower Limit
0 1 2 3 4 5 6 7 8 9 10
TIC
Mullion Temperature Profile Run 3 (CenterHeater On)
Fig Ell Mullion Temperature Profile Run 1 (LeftHeater On)
88
a
29
28
27
26
25~
i 24
23 e
22~ 21
20
19
18
Fig E12
i l middot middotmiddotmiddotmiddotlmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot+ 0 Upper Limit T 11 f =24474 + 011288x i imu bull z o Lower Limit
=tplusmntplusmnfrplusmnplusmnplusmn ~ I I I I Tmull ff ~ 28793 - o0784x
middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddott----middot------middotmiddotimiddot----middot-middotmiddot--middot-~-middotmiddotmiddot--middot----middotmiddot)middot
=ii=t=1=P-Ltplusmnt iii i T = 25599 - 00689xIfmiddotTTTmiddotmiddotrmiddot ~Ullff iii
T l1f =20552 + 01676x i~~imiddotimiddotmiddot
==~LL L LLLLL i i 1 ~ 1 ~
0 1 2 3 4 5 6 7 8 9 10
TIC I
Mullion Temperature Profile Run 2 (LeftlHeater On)
33 iii i i
-middot--middot(---middotmiddot--middotmiddot--middotmiddot+---middot-middotmiddotmiddotmiddot-middotmiddotmiddot~-middot--middot-------middoti---middot------~ o Upper Limit 32 Run 3
t bullbullbull +
Tm~llfz
T mu
1 1 1 1 1 o Lower Limit ~~31
=2713 ~ 0113~x j11Li30
a T ulff =30658 - 006506x 29~
IktlJ2~Li 28
27 e
26 =l=tt=tmiddotmiddottmiddott+~middot+=t=~ middotmiddot jmiddotjmiddottmiddottmiddotjmiddot T = 28288 - 00603x
iii i mullff 24
25
middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotQmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot+middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot~middotmiddotmiddot middotmiddotmiddotmiddotmiddotmiddotmiddotmiddot~middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot+middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot 11 fz = 2377 ~ 01788x IL11123 i i
22
0 1 2 3 4 5 6 7 8 9 10
TIC I
Fig E13 Mullion Temperature Profile Run 3 (LeftHeater On)
89
31
30
29
ltP ~u
J
1 T
-~Lti=t~-t--t i~+--Ij Tmu1lff =31473 middot005222x 28
1 1 1middot 1 l i l i bullbullbullbullbullbullbull__ bullbullbullbull_ bullbullbullbullbullbullbull~_bullbullbullbullbullbullbullbullbulla bullbullbullbullbullbullbullbullbullbullbull a 27
~ Tm~llfz = 26857 + 01734x _~__+_+II i
26
bullmiddotmiddotbullbullbullmiddotmiddotbullibullbullbullbullbullbullbullbullbullbullbullmiddotmiddotmiddotbullbullbullbullbullbullbullbullmiddotmiddotmiddotmiddot bullbullbullbullbullbullbullbullbull-i-~-i-ii25
JJ$~L-f$9 5 24
~ 23 middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotlmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot+middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot~middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot+middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1-middotmiddot T mllff =25622 bull 002~7X c-bullbullbullbullbullbullbullbullbullbullbullbull+ ~~ 22 rp 1 1 i i 1 1 1
21 = 19464 + 02548 jmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddott Upper Limitmullfz xii 0
4-bullbullbullbullbullbullbullbullbullbullbullbullimiddotmiddotmiddotbullbullbullbullbullbullmiddotf20 i 1 ~ 1
19
0 1 2 3 4 5 6 7 8 9 10
TIC I
Fig E14 Mullion Temperature Profile Run I (RightHeater On)
33 i
middotmiddotmiddotmiddotlaquomiddotmiddotmiddotmiddot------------------------------- c--------middotmiddotmiddot-middot-----------middotmiddotmiddot---middotmiddot--------l-----middot-----I-----32
= 2757 + 017006x ILLJ1
a
31
30
29~
i 28
Run2
TmulIfz
T~ulIfz ~
-~t=ii~Ii~~~~ i
27 middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot9-middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotT~~middotmiddotmiddotmiddotmiddot2s944-middot~middotmiddotO0278~middotmiddote 26~ r~rrTt+rr25
24 2320~ + O~S4x middotmiddotlmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotjmiddot ~ u~ L~t 23 middotmiddotmiddotmiddotmiddotmiddotmiddotmiddot~middotmiddotmiddotmiddotmiddotmiddotmiddot+middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot+middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot+middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotImiddotmiddotj 0 Lower Limit
22
0 1 2 3 4 5 6 7 8 9 10
TIC I
Fig EIS Mullion Temperature Profile Run 2 (RightlHeater On)
90
33 i i ~ _______ _ _~____ __ __-i--bullbullbullbullbullbullbullbull-t------ -- uu__~ ~ --~32
=1268931+ 0~4~14X 111131
30
a 29~
I 28
Run3
Tmullfz
i t+ I T
m
mnplusmn~~27 6 i 1 i 1 +++ T mullff =28912 - 002938x 26~ +middotmiddot++Imiddotjmiddott-25
= 22996 + 02312x 1middotmiddot+ 24
~~~~L lL1 0 ~23 ill 0 22
0 1 2 3 4 5 6 7 8 9 10
TIC
Fig E16 Mullion Temperature Profile Run 3 (RightHeater On)
91
APPENDIX F NUMERICAL SIMULATION EQUATIONS AND CODE
F1 Finite-Difference Equations
Figure Fl is a generic resistor network that is used as a base for all the finite-difference
equations The general fonn is
(Fl)
r----II ij+l
J
i j-l L ______--J
Fig F1 Generic Nodal Resistor Network
This makes it easy to simply plug in the different resistors for the different regions of the
section There are twelve resistors total The following table summarizes the resistors
needed to complete the model
Table F1 Model Resistors
Description Resistance [CIW]
Interior insulation x direction Rl= dx dymiddotkinsmiddotb
92
dyInterior insulation y direction R2= dx-kins-b
dySteel parallel with insulation y direction R3= km-dm-b + kins-(dx -dm)
dxR=Steel parallel with insulation x direction km-dm-b + kins-(dy -dm)
dyRs=Plastic parallel with insulation y direction
kp-dp-b + kins-(dx -dp)
dxPlastic parallel with insulation x direction R6= kp-dp-b + kins-(dy -dp)
heffa- (~- dm) + kinsSteel to exterior x direction R7= 2
heffo-kins-dy-b
heffa- (dY - dm) + kinsSteel to exterior y direction R - 28shyheffo-kins-dx-b
hefti- (dY _dm) + kinsSteel to interior y direction R9= 2
heffi-kins-dx-b
hefti- (~- dp) + kinsPlastic to interior x direction RIO= 2
heffi-kins-dy-b
Rll = hefti- (dJ -dP) + kinsPlastic to interior y direction
heffi-kins-dx-b
93
Steel skinplastic skin interface
2middotkmmiddotdmmiddotkpmiddotdpmiddotdxR12=----------------------~~----------------
2middotkmmiddotdmmiddotkpmiddotdpmiddotbmiddot(dy -dp) + (kpmiddotdp + kmmiddotdm)middotbmiddotdx2
F2 Wall Simulation Source Code
Program FiniteDiff
c This program simulates the conductive heat transfer through the wall section c of the refrigerator near the door gasket using Guass-Siedel iteration c The program allows for flexibility in the geometry and material properties c The program is a steady-state model
cVariable Definitions
c km = conductivity of the outer metal skin (Wm-K) c kins = conductivity of the polyurethane foam insulation (Wm-K) c kp conductivity of the inner plastic skin (Wm-K) c dm = thickness of the metal skin (mm) c dp = thickness of the plastic skin (mm) c b = depth of the section (m) c heffo = effective heat transfer coefficient on outside surfaces (Wm2-K) c heffi = effective heat transfer coefficient on inside surfaces (Wm2-K) c sl width of wall inSUlation (mm) c s2 length of wall section (mm) c s3 seal indentation (mm) c s4 seal width (mm) c s5 distance metal skin travels into cabinet (mm) c s6 distance platic skin travels out of cabinet (mm) c ns = number of nodes corresponding to the s regions above c rs = network resistors (m-eW) c i = integer values of distance along the x axis c j = integer values of distance along the y axis c imax maximum integer value in x direction c jmax maximum integer value in y direction c iter total number of iterations to converge c loop convergence flag c Qinl Heat flux per unit length across the outer boundary (Wm) c Qin2 Heat flux per unit length across the inner boundary (Wm) c Qdif Qinl - Qin2 (Wm) c Qpdif = percent difference between the heat fluxes Qinl and Qin2 c Ti Inside ambient temperature (e) c To = Outside ambient temperature (e)
cDeclare Variables
INTEGER nln2n3n4n5n6ijloopimaxjmaxiter INTEGER clflaglflag2 REAL kmkinskpdmdpdxdyheffoheffi REAL TiToQdifQpdifQinlQin2 REAL sls2s3s4s5s6lenoutlenin REAL rlr2r3r4r5r6r7r8r9rlOrllr12 REAL T(-1lOl-1lOl)bqlDsumlsum2 REAL Qm(lOl)qfluxm(lOl)fluxo(OlOl)fluxi(OlOl)
94
REAL fluxcen(0101)pfluxcen(0101)pfluxo(0101) REAL pfluxi(0101)pmaxdifoneDtolaq2Dqedge1
OPEN (10file-2Dcode(v11)out1position-rewind) OPEN (11file-2Dcode(v11)out2position=rewind)
cTest Parameters
c thermal conductivity of the outer metal skin (Wm K) km-540
c thermal conductivity of the wall insulation (Wm K) kins=0021
c thermal conductivity of the inner plastic skin (Wm K) kp=015
c thickness of the metal skin (mm) dm=065
c thickness of the plastic skin (mm) dp=25
c effective heat transfer coefficient on outside surfaces (Wm2-K) heffo=681
c effective heat transfer coefficient on inside surfaces (Wm2-K) heffi=610
c width of section (mm) sl=450
c length of section (mm) s2=2000
c depth of the section (m) b=10
c inside ambient temperature (C) Ti=95
c outside ambient temperature (C) To=210
c unit conversions dm=dm1000 dp=dp1000 sl=sl1000 s2=s21000
c specify 1-dimensional tolerance (t) oneDtol=30
cMesh Parameters
c specify the following nodal mesh parameters n1=20 n2=80 n3=1 n4=9 n5=10
c various mesh dimensions dx=sln1 dy=s2n2 s3=n3dx s4=n4dx s5=n5dx s6=sl-s5-dx n6=s6dx imax=n1-1 jmax=n2-1
cInitialize temperature matrix
DO 10 j=-1jmax+1 DO 20 i=-1imax+1 T(ij)=Ti
95
20 CONTINUE 10 CONTINUE
DO 30 j=Ojmax T(-Ij)=To
30 CONTINUE
DO 40 i=0n3 T(i-I)=To
40 CONTINUE
DO 50 j=Ojmax T(imax+lj)=Ti
50 CONTINUE
DO 60 i=n3+n4+1imax T(i-I)=Ti
60 CONTINUE
cResistors [m-CW]
c interior insulation x direction rl=dx(kinsdy)
c interior insulation y direction r2=dy(kinsdx)
c metalinsulation y direction r3=dy(kmdm+kins(dx-dm))
c metalinsulation x direction r4=dx(kmdm+kins(dy-dm))
c plasticinsulation y direction r5=dy(kpdp+kins(dx-dp))
c plasticinsulation x direction r6s dx(kpdp+kins(dy-dp))
c metal to exterior x direction r7=(heffolaquodx2)-dm)+kins)(heffokinsdy)
c metal to exterior y direction rB=(heffo laquody2)-dm) +kins)(heffokinsdx)
c metal to interior y direction r9=(heffilaquody2)-dm)+kins)(heffikinsdx)
c plastic to interior x direction rl0=(heffilaquodx2)-dp)+kins)(heffikinsdy)
c plastic to interior y direction rll=(heffilaquody2)-dp)+kins)(heffikinsdx)
c metalplastic interface rI2=(2kmdmkpdpdx)(2kmdmkpdp(dy-dp) + (kpdp+km dm)dxdx)
cxxxxxGuass-Siedel Iterationxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx loop=1 iter=1 DO WHILE (loop eq 1)
c Equations for row 0 i=O j=O CALL sseqn(Tr4r7r3rBijimaxjmax)
DO 70 i=ln3 j=O CALL sseqn(Tr4r4r2rBijimaxjmax)
70 CONTINUE
DO 75 i=n3+1n5-1
96
j=O IF (i le n3+n4) THEN
CALL sseqn(Tr4r4r21e20ijimaxjmax) ELSE
CALL sseqn(Tr4r4r2r9ijimaxjmax) ENDIF
75 CONTINUE
i=n5 j-O IF (i le n3+n4) THEN
CALL sseqn(Tr12r4r21e20ijimaxjmax) ELSE
CALL sseqn(Tr12r4r2r9ijimaxjmax) ENDIF
i=n5+1 j=O IF (i le n3+n4) THEN
CALL sseqn(Tr6r12r21e20ijimaxjmax) ELSE
CALL sseqn(Tr6r12r2rllijimaxjmax) ENDIF
DO 80 i=n5+2imax-l j=O IF (i le n3+n4) then
CALL sseqn(Tr6r6r21Oe20ijimaxjmax) ELSE
CALL sseqn(Tr6r6r2rllijimaxjmax) ENDIF
80 CONTINUE
i=imax j=O CALL sseqn(TrlOr6r5rllijimaxjmax)
c Equations for rows 1 thru jmax-l DO 90 j=ljmax-l
i=O CALL sseqn(Tr1r7r3r3ijimaxjmax)
DO 100 i=1imax-1 CALL sseqn(Tr1r1r2r2ijimaxjmax)
100 CONTINUE
i=imax CALL sseqn(Tr10r1r5r5ijimaxjmax)
90 CONTINUE
c Equations for row jmax j=jmax i=O CALL sseqn(Tr1r710e20r3ijimaxjmax)
DO 110 i=1imax-1 j=jmax CALL sseqn(Tr1r110e20r2ijimaxjmax)
110 CONTINUE
i=imax j=jmax CALL sseqn(Tr10r11Oe20r2ijimaxjmax)
97
c c c
Compute the difference in heat flux crossing the outer boundary and crossing the inner boundaryr ideally the difference should be zero
CALL balance(TToTidxdyn3n4imaxjmaxQdifQpdif c QinlQin2r7r9r8rlOrllb)
c Update loop variables iter-iter+l
c Convergence criterium IF (Qpdif le 20) then
loop-O ENDIF IF (iter eq 10000) THEN loop=O write(lO) Solution did not converge
ENDIF
END DO cxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
cHeat Transfer Calculations
c Compute 10 heat flux through wall CALL oneD (ToTiheffoheffikmkinskpdmdpslqlD)
c Compute the flux thru wall at each node on the c outside and inside walls [Wm2) Also the flux c in the x-direction across the center line of the c section
cl-int(nl2) fluxcen(0)=(1(r4dy))(T(cl0)-T(cl+l0)) fluxo(0)=(1(r7dy))(To-T(00)) fluxi(O)=(l(rlOdy))(T(imaxO)-Ti) DO 112 j=ljmax
fluxcen(j)=(l(rldy))(T(clj)-T(cl+lj)) fluxo(j)=(1(r7dy))(To-T(0j)) flumiddotxi (j) =(1 (rlOdy)) (T (imax j)-Ti)
112 CONTINUE
c Determine the percent of steady-state 10 losses DO 113 j=Ojmax
pfluxcen(j)=(fluxcen(j)qlD) 100 pfluxo(j)=(fluxo(j)qlD)lOO pfluxi(j)=(fluxi(j)qlD)lOO
113 CONTINUE
c Determine where the heat transfer becomes 10 c based on a criticle percentage
flagl=O DO 114 j=O jmax
a=abs(pfluxcen(j)-lOOO) IF (j ne jmax) THEN
IF (a le oneDtol) THEN jstar=j
ENDIF ELSE
IF (a le oneDtol) THEN jstar=j
ELSE flagl=l
ENDIF ENDIF
98
114 CONTINUE
c Determine the edge loss by subtracting the 10 heat c transfer from the heat transfer in the 20 region c across the centerline
flag2=0 IF (flagl eq 0) THEN
q2D=00 DO 115 j=O jstar
q2D-q2D+fluxcen(j) 115 CONTINUE
qedgel=q2D-qlD ELSE
flag2=1 ENDIF
c 10 heat flux along metal skin under the seal into c the cabinet [Wm2J Fluxes for all metal nodes are c computed as well as an average flux The flux from c node (n3+l0) to node (n3+20) is given as qlDm(l) c and so on Assume the temperature of the metal skin c is the temperature of the node at that location
suml=OO sum2=00 DO 119 i=n3+1n3+n4-l
Qm(i)=laquokmdmb)dx)(T(i0)-T(i+10raquo qfluxm(i)=(kmdx)(T(iO)-T(i+lOraquo suml=suml+Qm(i) sum2=sum2+qfluxm(i)
119 CONTINUE pmaxdif=laquoQm(n3+n4-l)-Qm(n3+1raquoQm(n3+lraquo100 qedge2-qfluxm(cl)
cOutput
c Output nodal temperatures to separate file DO 120 j=Ojmax
write(ll) (T(ij)i=Oimax) 120 CONTINUE
c Output flux info to a different file write(10) INPUT PARAMETERS write(lO) write (10 ) Section Dimensions (mm) write(lO) Width sl1000 write (10 ) Length s21000 write(10) Depth blOOO write(10) Steel skin thickness dmlOOO write(lO) Plastic skin thickness dplOOO write(lO) write(10) Mesh Geometry write(10) dx dxlOOO write(lO) dy dylOOO write(lO) Number nodes in x-direction n1 write(lO) Number nodes in y-direction n2 write(lO) Number of steel skin nodes write(lO) (including corner 00) n5+l write(10) Steel nodes under the seal n3+1 ton3+n4 write(10) write(lO) Steel skin conductivity (Wm K) km write(lO) Foam insulation conductivity (Wm K) kins write(lO) Plastic skin conductivity (Wm K) kp write(lO) Outside h (Wm2 K) heffo write(lO) Inside h (Wm2 K) heffi
99
write(10) Outside Temp (C) To write(10) Inside Temp (C) Ti write(10) write (10 ) write(10) write(10) OUPUT PARAMETERS write (10 ) write(10) Number of iterations iter write(10) write(10) Heat Transfer for the Section write(10) OVerall Heat Transfer (W) Qin1 write(10) 10 Heat Flux Thru Wall (Wm2) q1D write (10 ) write(10) Heat Transfer Along Metal Skin Under Seal write(10) node to node qm[Wm2J Qm[WJ DO 135 i=n3+1n3+n4-1
write(10) i i+1 qfluxm(i) Qm(i) 135 CONTINUE
write (10 ) Maximum difference () abs (pmaxdif) write(10) IF (flag2 eq 1) THEN
write(10) The mesh does not extend far enough write(10) in the y-direction to reach 10 heat write(10) transfer for the specified tolerance write(10) ofoneDtol
ELSE write (10 ) Edge loss computed from qe=q2D-q1D qedge1 write (10 ) write(10) Edge loss computed directly from write(10) steel skin ~T at centerline qedge2
ENDIF write (10 ) write (10 ) write(10) Heat fluxes in thru the section write(10) along the centerline [Wm2J write (10 ) write(10) j flux 10 DO 136 j=Ojmax
write(10) j fluxcen(j) pfluxcen(j) 136 CONTINUE
PAUSE STOP END
C
SUBROUTINE sseqn (Trplusirminusirplusjrminusj i jimax jmax)
c This subroutine computes the temperature at node (ij) c given the temperatures of the surrounding nodes and c the resistances leading to these nodes
INTEGER ijimaxjmax REAL T(-1101-1101)rplusirminusirplusjrminusj REAL c1c2c3c4c5
c1=1rplusi c2=1rminusi c3=1rplusj c4=1rminusj c5=c1+c2+c3+c4
T(ij)=(1c5)(c1T(i+1j)+c2T(i-1j)+c3T(ij+1)+c4T(ij-1raquo
100
RETURN END
C
SUBROUTINE balance(TToTidxdyn3n4imaxjmaxQdifQpdif c Qin1Qin2r7r8r9r10r11b)
c This subroutine computes the steady-state heat balance c for the cross-section
INTEGER imaxjmaxijn3n4 REAL T(-1101-1101)TlToQin1Qin2dydx REAL r7r8r9r10r11b
c Compute the heat entering Qin1 [Wj Qin1=00 DO 10 jOjmax
Qin1=Qin1+(b(r7))(To-T(0j)) 10 CONTINUE
DO 20 i=0n3 Qin1=Qin1+(b(r8))(To-T(i0))
20 CONTINUE
c Compute the heat leaving Qin2 [Wj Qin2=00 DO 30 j=Ojmax
Qin2=Qin2+(b(r10))(T(imaxj)-Ti) 30 CONTINUE
DO 40 i=n3+n4+1imax IF (i le nS) then
Qin2=Qin2+(b(r9))(T(i0)-Ti) ELSE
Qin2=Qin2+(b(r11))(T(i0)-Ti) ENDIF
40 CONTINUE
c Compute the absolute difference in heat fluxes [Wj Qdif=abs(Qin2-Qin1)
c Compute the percent difference in the heat transfers [Wj Qpdif=(QdifQin1) 100
RETURN END
C
SUBROUTINE oneD (ToTiheffoheffikmkinskpdmdpslqlD)
c This subroutine compute the one-dimensional c heat flux through the section wall
INTEGER i REAL ToTiheffoheffikmkinskpdmdpsl REAL q1DReqdins
dins=sl-dm~dp
Req=(lheffo) + (dmkm) + (dinskins) +(dpkp)+(lheffi) q1D=(To-Ti)Req
RETURN END
101
F3 Fresh Food Wan Simulation Output
INPUT PARAMETERS
Section Dimensions (mm) Width 4500 Length 2000 Depth 1000 Steel skin thickness 6500 Plastic skin thickness 2500
Mesh Geometry dx 2250 dy 2500 Number nodes in x-direction 20 Number nodes in y-direction 80 Number of steel skin nodes (including corner 00) 11 Steel nodes under the seal 2 to 10
Steel skin conductivity (Wm K) 5400 Foam insulation conductivity (Wm K) 21000E-02 Plastic skin conductivity (Wm K) 1500 Outside h (Wm2 K) 6810 Inside h (Wm2 K) 6100 Outside Temp (C) 2100 Inside Temp (C) 4000
OUPUT PARAMETERS
Number of iterations 5318
10 Heat Flux Thru Wall (Wm2) 9132
Heat Transfer Along Metal Skin Under Seal node to node qm[Wm2] Qm[W]
2 3 1619 1092 3 4 1612 1081 4 5 1660 1019 5 6 1645 1010 6 1 1626 1051 1 8 1601 1041 8 9 1569 1020 9 10 1521 9922
Maximum difference () 9101
Edge loss computed directly from steel skin 1T at centerline 1645
Heat fluxes in thru the section along the centerline [Wm2]
j flux 10 0 4284 4691 1 2246 2459 2 3513 3841 3 4554 4981 4 5311 5881 5 6001 6512 6 6488 1104 1 6868 1520
102
10
20
30
40
50
60
70
8 7169 7850 9 7412 8117
7612 8335 11 7778 8517 12 7918 8670 13 8037 8800 14 8139 8912 15 8227 9008 16 8303 9092 17 8369 9164 18 8428 9228 19 8479 9285
8525 9334 21 8565 9379 22 8601 9418 23 8634 9454 24 8663 9486 25 8690 9515 26 8714 9542 27 8736 9566 28 8756 9588 29 8775 9609
8793 9628 31 8809 9645 32 8824 9662 33 8838 9677 34 8851 9692 35 8863 9705 36 8875 9718 37 8886 9730 38 8896 9742 39 8906 9752
8916 9763 41 8925 9772 42 8933 9782 43 8941 9791 44 8949 9799 45 8956 9807 46 8963 9815 47 8970 9822 48 8976 9829 49 8982 9836
8988 9842 51 8994 9848 52 8999 9854 53 9004 9859 54 9009 9864 55 9013 9869 56 9017 9874 57 9021 9878 58 9025 9883 59 9029 9887
9032 9890 61 9036 9894 62 9039 9897 63 9042 9901 64 9044 9903 65 9047 9906 66 9049 9909 67 9051 9911 68 9053 9913 69 9055 9915
9057 9917 71 9058 9919
103
72 9059 9920 73 9061 9921 74 9062 9922 75 9062 9923 76 9063 9924 77 9063 9924 78 9064 9925 79 9064 9925
j local Qwall [Wl
-1 3215 0 -45410E-02 1 -50708E-02 2 -40940E-02 3 -33836E-02 4 -27620E-02 5 -23180E-02 6 -1 9628E-02 7 -1 6076E-02 8 -1 4300E-02 9 -12524E-02 10 -10748E-02 11 -98601E-03 12 -89722E-03 13 -80842E-03 14 -71962E-03 15 -63081E-03 16 -63082E-03 17 -54202E-03 18 -54202E-03 19 -45322E-03 20 -45322E-03 21 -45322E-03 22 -45321E-03 23 -36442E-03 24 -36442E-03 25 -36442E-03 26 -27562E-03 27 -27561E-03 28 -27561E-03 29 -27561E-03 30 -27561E-03 31 -18682E-03 32 -18682E-03 33 -27561E-03 34 -18682E-03 35 -18682E-03 36 -18681E-03 37 -18682E-03 38 -98018E-04 39 -98018E-04 40 -98018E-04 41 -98018E-04 42 -98018E-04 43 -98018E-04 44 -98018E-04 45 -98018E-04 46 -98018E-04 47 -18682E-03 48 -98018E-04 49 -98018E-04 50 -98018E-04 51 -98018E-04 52 -98018E-04
104
53 -98018E-04 54 -92160E-05 55 -98018E-04 56 -98018E-04 57 -98018E-04 58 -98018E-04 59 -98018E-04 60 -92160E-05 61 -98018E-04 62 -92160E-05 63 -98018E-04 64 -98018E-04 65 -92160E-05 66 -98018E-04 67 -98018E-04 68 -92245E-05 69 -92245E-05 70 -98018E-04 71 -98018E-04 72 -98018E-04 73 -92160E-05 74 -92160E-05 75 -92160E-05 76 -92160E-05 77 -92160E-05 78 -92160E-05 79 -92160E-05
Qwallff [Wm21 = 1442 Qwallff [WI = 2775
Fresh Food Nodal Temperatures
x(mm) v(mm) 1125 3375 5625 7875 10125 12375 14625 16875 19125 21375
125 1761 1755 1748 1741 1734 1727 172 1713 1706 17 375 1768 1753 1738 1723 1707 169 1671 165 1624 1589 625 1775 1752 173 1706 1682 1656 1626 1593 1552 15 875 1781 1751 1722 1691 1659 1625 1587 1544 1494 1434
1125 -1787 1751 1715 1678 1639 1598 1553 1504 1448 1384 1375 1792 1751 1709 1667 1622 1576 1526 1471 1412 1346 1625 1798 1752 1705 1658 1609 1557 1503 1446 1384 ll17 1875 1803 1753 1702 165 1597 1543 1485 1425 1362 1294 2125 1808 1754 17 1645 1589 1531 1471 1409 1344 1276 2375 1813 1756 1699 1641 1582 1522 146 1396 133 1262 2625 1817 1758 1698 1638 1577 1515 1451 1386 132 1251 2875 1822 176 1698 1636 1573 151 1445 1379 1311 1242 3125 1826 1762 1699 1635 1571 1506 144 1373 1304 1235 3375 183 1765 17 1635 1569 1503 1436 1368 1299 1229 3625 1834 1768 1701 1635 1568 1501 1433 1364 1295 1225 3875 1837 177 1703 1635 1568 15 1431 1362 1292 1222 4125 1841 1773 1705 1636 1568 1499 143 136 129 1219 4375 1845 1776 1707 1638 1568 1499 1429 1359 1289 1218 4625 1848 1778 1709 1639 1569 1499 1429 1358 1288 1216 4875 1851 1781 1711 164 157 15 1429 1358 1287 1216 5125 1854 1784 1713 1642 1571 15 1429 1358 1287 1215 5375 1857 1786 1715 1644 1573 1501 143 1358 1287 1215 5625 186 1789 1717 1646 1574 1502 1431 1359 1287 1215
105
5875 1863 1791 1719 1647 1576 1504 1432 136 1288 1215 6125 1866 1794 1721 1649 1577 1505 1433 136 1288 1216 6375 1868 1796 1723 1651 1579 1506 1434 1361 1289 1216 6625 1871 1798 1725 1653 158 1508 1435 1362 129 1217 6875 1873 18 1727 1655 1582 1509 1436 1363 1291 1218 7125 1876 1803 1729 1656 1583 151 1437 1364 1291 1218 7375 1878 1805 1731 1658 1585 1512 1439 1366 1292 1219 7625 188 1807 1733 166 1587 1513 144 1367 1293 122 7875 1882 1809 1735 1661 1588 1515 1441 1368 1294 1221 8125 1884 181 1737 1663 159 1516 1442 1369 1295 1222 8375 1886 1812 1738 1665 1591 1517 1444 137 1296 1223 8625 1888 1814 174 1666 1592 1519 1445 1371 1297 1224 8875 189 1816 1742 1668 1594 152 1446 1372 1298 1225 9125 1892 1817 1743 1669 1595 1521 1447 1373 1299 1225 9375 1893 1819 1745 1671 1596 1522 1448 1374 13 1226 9625 1895 182 1746 1672 1598 1524 1449 1375 1301 1227 9875 1896 1822 1748 1673 1599 1525 145 1376 1302 1228 10125 1898 1823 1749 1674 16 1526 1451 1377 1303 1229 10375 1899 1825 175 1676 1601 1527 1452 1378 1304 123 10625 1901 1826 1751 1677 1602 1528 1453 1379 1305 123 10875 1902 1827 1753 1678 1603 1529 1454 138 1305 1231 11125 1903 1828 1754 1679 1604 153 1455 1381 1306 1232 11375 1904 183 1755 168 1605 1531 1456 1381 1307 1232 11625 1906 1831 1756 1681 1606 1532 1457 1382 1308 1233 11875 1907 1832 1757 1682 1607 1532 1458 1383 1308 1234 12125 1908 1833 1758 1683 1608 1533 1458 1384 1309 1234 12375 1909 1834 1759 1684 1609 1534 1459 1384 131 1235 12625 191 1835 176 1685 161 1535 146 1385 131 1235 12875 1911 1836 1761 1686 1611 1536 1461 1386 1311 1236 13125 1912 1837 1761 1686 1611 1536 1461 1386 1311 1236 13375 1913 1837 1762 1687 1612 1537 1462 1387 1312 1237 13625 1913 1838 1763 1688 1613 1538 1462 1387 1312 1237 13875 1914 1839 1764 1688 1613 1538 1463 1388 1313 1238 14125 1915 184 1764 1689 1614 1539 1464 1388 1313 1238 14375 1916 184 1765 169 1614 1539 1464 1389 1314 1239 14625 1916 1841 1766 169 1615 154 1465 1389 1314 1239 14875 1917 1842 1766 1691 1616 154 1465 139 1315 1239 15125 1918 1842 1767 1691 1616 1541 1465 139 1315 124 15375 1918 1843 1767 1692 1616 1541 1466 1391 1315 124 15625 1919 1843 1768 1692 1617 1542 1466 1391 1316 124 15875 1919 1844 1768 1693 1617 1542 1467 1391 1316 1241 16125 192 1844 1769 1693 1618 1542 1467 1392 1316 1241 16375 192 1844 1769 1694 1618 1543 1467 1392 1317 1241 16625 192 1845 1769 1694 1618 1543 1468 1392 1317 1241 16875 1921 1845 177 1694 1619 1543 1468 1392 1317 1242 17125 1921 1846 177 1694 1619 1544 1468 1393 1317 1242 17375 1921 1846 177 1695 1619 1544 1468 1393 1317 1242 17625 1922 1846 1771 1695 1619 1544 1469 1393 1318 1242 17875 1922 1846 1771 1695 162 1544 1469 1393 1318 1242 18125 1922 1847 1771 1695 162 1544 1469 1393 1318 1243 18375 1922 1847 1771 1696 162 1545 1469 1394 1318 1243 18625 1923 1847 1771 1696 162 1545 1469 1394 1318 1243 18875 1923 1847 1771 1696 162 1545 1469 1394 1318 1243 19125 1923 1847 1772 1696 162 1545 1469 1394 1318 1243 19375 1923 1847 1772 1696 162 1545 1469 1394 1318 1243 19625 1923 1847 1772 1696 1621 1545 1469 1394 1318 1243 19875 1923 1847 1772 1696 1621 1545 1469 1394 1318 1243
106
x(mm) y(mm) 23625 25875 28125 30375 32625 34875 37125 39375 41625 43875
125 1694 1662 1287 1033 8577 7336 6444 5795 5324 4995 375 1536 144 125 1068 9163 7946 6974 6189 5532 4944 625 1431 1334 1203 1066 9379 8252 7275 6423 5657 4935 875 136 127 1164 1051 9408 8374 7423 6548 573 4941
1125 131 1226 1132 1034 9353 8394 7477 6605 5766 4948 1375 1273 1193 1107 1017 9262 836 7478 6618 5779 4952 1625 1245 1168 1086 1002 9162 8302 7449 6607 5776 4951 1875 1223 1148 1069 9886 9064 8236 7408 6583 5764 4948 2125 1205 1132 1055 977 8974 8169 7362 6554 5747 4941 2375 1191 1119 1044 9671 8893 8107 7316 6522 5728 4933 2625 118 1108 1034 9588 8824 8051 7273 6492 5709 4925 2875 1172 11 1026 9518 8764 8002 7235 6464 5691 4916 3125 1164 1093 102 946 8713 796 7201 6439 5674 4908 3375 1159 1087 1015 9412 8671 7924 7172 6417 566 49 3625 1154 1083 101 9373 8636 7894 7148 6399 5647 4894 3875 1151 1079 1007 9341 8608 7869 7128 6383 5636 4888 4125 1148 1077 1004 9316 8585 7849 7111 637 5627 4883 4375 1146 1074 1002 9296 8566 7833 7097 6359 5619 4879 4625 1145 1073 1001 9281 8552 7821 7087 6351 5613 4875 4875 1144 1072 9995 927 8541 7811 7078 6344 5609 4872 5125 1143 1071 9987 9261 8533 7803 7072 6339 5605 487 5375 1143 1071 9982 9256 8528 7798 7067 6335 5602 4868 5625 1143 107 9979 9253 8524 7795 7064 6332 56 4867 5875 1143 107 9978 9251 8522 7793 7062 6331 5599 4866 6125 1143 1071 9979 9251 8522 7792 7061 633 5598 4866 6375 1144 1071 9981 9252 8523 7792 7061 633 5598 4865 6625 1144 1071 9984 9255 8524 7793 7062 633 5598 4865 6875 1145 1072 9988 9258 8526 7795 7063 6331 5598 4865 7125 1145 1072 9993 9261 8529 7797 7065 6332 5599 4866 7375 1146 1073 9998 9265 8533 78 7067 6333 56 4866 7625 1147 1074 10 927 8536 7803 7069 6335 5601 4867 7875 1148 1074 1001 9275 854 7806 7072 6337 5602 4867 8125 1148 1075 1001 928 8545 7809 7074 6339 5603 4868 8375 1149 1076 1002 9285 8549 7813 7077 6341 5605 4869 8625 115 1076 1003 929 8553 7817 708 6343 5606 4869 8875 1151 1077 1003 9295 8558 782 7083 6345 5608 487 9125 1152 1078 1004 93 8562 7824 7086 6347 5609 4871 9375 1152 1078 1004 9306 8567 7828 7089 635 5611 4872 9625 1153 1079 1005 9311 8571 7831 7092 6352 5612 4873 9875 1154 108 1006 9316 8575 7835 7094 6354 5614 4873 10125 1155 108 1006 9321 858 7838 7097 6356 5615 4874 10375 1155 1081 1007 9326 8584 7842 71 6358 5617 4875 10625 1156 1082 1007 933 8588 7845 7103 636 5618 4876 10875 1157 1082 1008 9335 8592 7848 7105 6362 5619 4876 11125 1157 1083 1008 9339 8596 7852 7108 6364 5621 4877 11375 1158 1083 1009 9344 8599 7855 711 6366 5622 4878 11625 1158 1084 1009 9348 8603 7858 7113 6368 5623 4879 11875 1159 1084 101 9352 8606 7861 7115 637 5625 4middot879 12125 116 1085 101 9356 861 7864 7117 6372 5626 488 12375 116 1085 1011 936 8613 7866 712 6373 5627 488 12625 1161 1086 1011 9363 8616 7869 7122 6375 5628 4881 12875 1161 1086 1011 9367 8619 7871 7124 6376 5629 4882 13125 1162 1087 1012 937 8622 7874 7126 6378 563 4882 13375 1162 1087 1012 9373 8625 7876 7128 6379 5631 4883 13625 1162 1087 1013 9376 8627 7878 7129 6381 5632 4883
107
13875 1163 1088 1013 9379 863 788 7131 6382 5633 4884 14125 1163 1088 1013 9382 8632 7882 7133 6383 5634 4884 14375 1164 1089 1013 9384 8634 7884 7134 6384 5634 4885 14625 1164 1089 1014 9387 8636 7886 7136 6385 5635 4885 14875 1164 1089 1014 9389 8638 7888 7137 6386 5636 4885 15125 1165 1089 1014 9392 864 7889 7138 6387 5637 4886 15375 1165 109 1015 9394 8642 7891 714 6388 5637 4886 15625 1165 109 1015 9396 8644 7892 7141 6389 5638 4886 15875 1165 109 1015 9398 8646 7894 7142 639 5638 4887 16125 1166 109 1015 9399 8647 7895 7143 6391 5639 4887 16375 1166 1091 1015 9401 8649 7896 7144 6392 5639 4887 16625 1166 1091 1016 9403 865 7897 7145 6392 564 4888 16875 1166 1091 1016 9404 8651 7898 7146 6393 564 4888 17125 1167 1091 1016 9405 8652 7899 7146 6394 5641 4888 17375 1167 1091 1016 9406 8653 79 7147 6394 5641 4888 17625 1167 1091 1016 9407 8654 7901 7148 6395 5641 4888 17875 1167 1092 1016 9408 8655 7902 7148 6395 5642 4889 18125 1167 1092 1016 9409 8656 7902 7149 6395 5642 4889 18375 1167 1092 1016 941 8656 7903 7149 6396 5642 4889 18625 1167 1092 1016 9411 8657 7903 715 6396 5642 4889 18875 1167 1092 1017 9411 8657 7904 715 6396 5643 4889 19125 1167 1092 1017 9412 8658 7904 715 6396 5643 4889 19375 1167 1092 1017 9412 8658 7904 715 6397 5643 4889 19625 1167 1092 1017 9412 8658 7904 715 6397 5643 4889 19875 1168 1092 1017 9412 8658 7904 715 6397 5643 4889
F4 Freezer Wall Simulation Output
INPUT PARAMETERS
Section Dimensions (mm) Width 5600 Length 2000 Depth 1000 Steel skin thickness 6500 Plastic skin thickness 2500
Mesh Geometry dx 2800 dy 2500 Number nodes in x-direction 20 Number nodes in y-direction 80 Number of steel skin nodes (including corner 00) 9 Steel nodes under the seal 2 to 8
Steel skin conductivity (Wm K) 5400 Foam insulation conductivity (Wm K) 27000E-02 Plastic skin conductivity (Wm K) 1500 Outside h (Wm2 K) 6870 Inside h (Wm2 K) 6410 Outside Temp (C) 2100 Inside Temp (C) -1000
OUPUT PARAMETERS
108
Number of iterations 5409
Heat Transfer for the Section OVerall Heat Transfer (WI 4518 10 Heat Flux Thru Wall (Wm21 1362
Heat Transfer Along Metal Skin Under Seal node to node
2 3 3 4 4 5 5 6 6 7 7 8
Maximum difference
qm[Wm2) Om(W) 3026 1967 3008 1955 2981 1938 2944 1914 2892 1880 2820 1833
(1 6799
Edge loss computed from qe=q20-q1D 1760
Edge loss compusteel skin AT
ted directly from at centerline 2981
Heat fluxes in thru the section along the centerline [Wm2)
j flux UO 0 7762 5698 1 3711 2724 2 5678 41 68 3 7275 5341 4 8508 6246 5 9437 6927 6 1013 7438 7 1066 7823 8 1106 8117 9 1137 8347 10 1162 8529 11 1182 8678 12 1199 8801 13 1213 8904 14 1225 8992 15 1235 9068 16 1244 9135 17 1252 9193 18 1259 9245 19 1266 9291 20 1271 9333 21 1276 9370 22 1281 9405 23 1285 9436 24 1289 9464 25 1293 9491 26 1296 9515 27 1299 9538 28 1302 9559 29 1305 9578 30 1307 9596 31 1310 9614 32 1312 9630 33 1314 9645 34 1316 9659 35 1318 9673 36 1319 9685 37 1321 9697
109
38 1323 9709 39 1324 9720 40 1325 9730 41 1327 9740 42 1328 9749 43 1329 9758 44 1330 9767 45 1332 9775 46 1333 9783 47 1334 97bull 90 48 1335 9797 49 1336 9804 50 1336 9810 51 1337 9816 52 1338 9822 53 1339 9828 54 1340 9833 55 1340 9838 56 1341 9843 57 1341 9847 58 1342 9852 59 1343 9856 60 1343 9859 61 1344 9863 62 1344 9866 63 1344 9870 64 1345 9873 65 1345 9875 66 1346 9878 67 1346 9880 68 1346 9882 69 1347 9884 70 1347 9886 71 1347 9888
72 1347 9889 73 1347 9891 74 1347 9892 75 1348 9893 76 1348 9893 77 1348 9894 78 1348 9894 79 1348 9894
j local Qwall [WI
-1 3067 0 -36774E-02 1 -40214E-02 2 -32314E-02 3 -25994E-02 4 -20859E-02 5 -16909E-02 6 -14144E-02 7 -12169E-02 8 -10589E-02 9 -90092E-03 10 -78242E-03 11 -70342E-03 12 -66392E-03 13 -58492E-03 14 -54542E-03 15 -50592E-03 16 -46642E-03 17 -42692E-03 18 -42692E-03
110
19 -38742E-03 20 -34792E-03 21 -30842E-03 22 -30842E-03 23 -30842E-03 24 -26892E-03 25 -26892E-03 26 -22942E-03 27 -22942E-03 28 -22942E-03 29 -22942E-03 30 -18992E-03 31 -1 8992E-03 32 -18992E-03 33 -18992E-03 34 -1 8992E-03 35 -1 5042E-03 36 -1 8992E-03 37 -15042E-03 38 -1 5042E-03 39 -11092E-03 40 -11092E-03 41 -11092E-03 42 -11092E-03 43 -11092E-03 44 -11092E-03 45 -11092E-03 46 -11092E-03 47 -71417E-04 48 -11092E-03 49 -71421E-04 50 -11092E-03 51 -71417E-04 52 -11092E-03 53 -71417E-04 54 -71421E-04 55 -71421E-04 56 -71417E-04 57 -31916E-04 58 -31920E-04 59 -31916E-04 60 -31916E-04 61 -71417E-04 62 -11421E-04 63 -71421E-04 64 -31920E-04 65 -31920E-04 66 -71417E-04 67 -31916E-04 68 -71417E-04 69 -31920E-04 70 -71421E-04 71 -31920E-04 72 -31920E-04 73 -71417E-04 74 -31916E-04 75 -31916E-04 76 -31916E-04 77 -31916E-04 78 -71417E-04 79 -71417E-04
Qwallfz [Wm2J = 2895 Qwallfz [WJ = 2721
111
Freezer Wan Nodal Temperatures
x(mm) y1mm 14 42 70 98 126 154 182 210 238 266
125 1507 1492 1477 1461 1445 143 1415 14 1385 1338 375 1519 1489 1458 1426 1392 1353 1307 1247 1154 972 625 1531 1486 1441 1393 1341 1282 1212 1121 9925 7989 875 1542 1484 1425 1363 1296 1221 1132 1023 8837 7014
1125 1553 1483 1412 1338 1258 117 1069 9508 809 6396 1375 1563 1483 1401 1317 1227 1129 102 8969 7563 5974 1625 1572 1483 1393 13 1202 1097 9824 8568 7184 5673 1875 1582 1485 1387 1287 1182 1072 9537 8269 6906 5452 2125 1591 1488 1384 1277 1167 1053 9321 8046 67 5288 2375 1599 1491 1382 1271 1157 1039 916 7881 6547 5164 2625 1608 1495 1381 1266 1149 1028 9041 7758 6433 5071 2875 1616 1499 1382 1264 1144 1021 8955 7668 6349 5002 3125 1623 1504 1384 1263 114 1016 8895 7604 6288 495 3375 1631 1509 1386 1263 1139 1013 8854 7559 6245 4913 3625 1638 1514 1389 1264 1138 1011 8829 753 6216 4888 3875 1645 1519 1393 1266 1139 1011 8816 7513 6198 4872 4125 1652 1524 1396 1269 114 1011 8813 7505 6188 4863 4375 1658 1529 14 1271 1142 1012 8817 7505 6185 486 4625 1664 1534 1405 1275 1144 1014 8826 751 6188 4861 4875 167 1539 1409 1278 1147 1016 884 752 6195 4867 5125 1676 1544 1413 1281 115 1018 8858 7533 6206 4875 5375 1682 1549 1417 1285 1153 102 8877 755 6219 4886 5625 1687 1554 1421 1289 1156 1023 8899 7568 6235 4899 5875 1692 1559 1425 1292 1159 1026 8923 7588 6252 4914 6125 1698 1563 143 1296 1162 1028 8947 7609 627 493 6375 1702 1568 1434 1299 1165 1031 8972 763 6289 4946 6625 1707 1572 1438 1303 1169 1034 8997 7653 6308 4964 6875 1712 1576 1441 1306 1172 1037 9022 7675 6329 4982 7125 1716 158 1445 131 1175 104 9048 7698 6349 5 7375 172 1584 1449 1313 1178 1043 9073 7721 6369 5018 7625 1724 1588 1452 1317 1181 1045 9098 7744 639 5036 7875 1728 1592 1456 132 1184 1048 9123 7766 641 5054 8125 1732 1595 1459 1323 1187 1051 9147 7788 643 5072 8375 1736 1599 1462 1326 1189 1053 917 781 645 509 8625 1739 1602 1465 1329 1192 1056 9194 7831 6469 5108 8875 1743 1605 1468 1332 1195 1058 9216 7852 6488 5125 9125 1746 1609 1471 1334 1197 1061 9238 7872 6507 5142 9375 1749 1612 1474 1337 12 1063 926 7892 6525 5158 9625 1752 1615 1477 134 1202 1065 9281 7911 6542 5174 9875 1755 1617 148 1342 1205 1067 9301 793 656 519 10125 1758 162 1482 1344 1207 1069 9321 7948 6576 5205 10375 1761 1623 1485 1347 1209 1071 934 7966 6593 522 10625 1763 1625 1487 1349 1211 1073 9358 7983 6608 5234 10875 1766 1627 1489 1351 1213 1075 9376 7999 6623 5248 11125 1768 163 1491 1353 1215 1077 9393 8015 6638 5262 11375 1771 1632 1494 1355 1217 1079 941 8031 6652 5275 11625 1773 1634 1496 1357 1219 1081 9426 8045 6666 5287 11875 1775 1636 1498 1359 1221 1082 9441 806 6679 53 12125 1777 1638 1499 1361 1222 1084 9456 8073 6692 5311 12375 1779 164 1501 1362 1224 1085 947 8087 6704 5322 12625 1781 1642 1503 1364 1225 1087 9483 8099 6716 5333 12875 1783 1644 1505 1366 1227 1088 9496 8111 6727 5344
112
13125 1784 1645 1506 1367 1228 109 9509 8123 6738 5353 13375 1786 1647 1508 1369 123 1091 9521 8134 6748 5363 13625 1788 1648 1509 137 1231 1092 9532 8145 6758 5372 13875 1789 165 151 1371 1232 1093 9543 8155 6768 5381 14125 1791 1651 1512 1373 1233 1094 9554 8165 6777 5389 14375 1792 1652 1513 1374 1235 1095 9564 8174 6785 5397 14625 1793 1654 1514 1375 1236 1096 9573 8183 6793 5404 14875 1794 1655 1515 1376 1237 1097 9582 8191 6801 5412 15125 1796 1656 1516 1377 1238 1098 959 8199 6808 5418 15375 1797 1657 1517 1378 1238 1099 9598 8206 6815 5425 15625 1798 1658 1518 1379 1239 11 9606 8213 6822 5431 15875 1799 1659 1519 138 124 1101 9613 822 6828 5436 16125 18 166 152 138 1241 1101 9619 8226 6834 5442 16375 18 1661 1521 1381 1242 1102 9626 8232 6839 5446 16625 1801 1661 1521 1382 1242 1103 9631 8237 6844 5451 16875 1802 1662 1522 1382 1243 1103 9637 8242 6848 5455 17125 1803 1663 1523 1383 1243 1104 9642 8247 6853 5459 17375 1803 1663 1523 1384 1244 1104 9646 8251 6857 5463 17625 1804 1664 1524 1384 1244 1105 965 8255 686 5466 17875 1804 1664 1524 1384 1245 1105 9654 8258 6863 5469 18125 1805 1665 1525 1385 1245 1105 9657 8261 6866 5471 18375 1805 1665 1525 1385 1245 1106 966 8264 6869 5474 18625 1805 1665 1525 1385 1246 1106 9662 8266 6871 5476 18875 1806 1666 1526 1386 1246 1106 9664 8268 6872 5477 19125 1806 1666 1526 1386 1246 1106 9666 827 6874 5479 19375 1806 1666 1526 1386 1246 1106 9667 8271 6875 548 19625 1806 1666 1526 1386 1246 1107 9668 8271 6876 548 19875 1806 1666 1526 1386 1246 1107 9668 8272 6876 5481
x(mm) v(mm) 294 322 350 378 406 434 462 490 518 546
125 549 054 -27 -5 -624 -727 -8 -85 -89 -92 375 548 171 -12 -338 -5 -624 -719 -795 -858 -914 625 51 22 -032 -24 -408 -543 -654 -748 -83 -907 875 474 238 0182 -175 -34 -482 -603 -71 -807 -898
1125 445 243 048 -132 -293 -436 -564 -68 -787 -89 1375 423 243 0653 -103 -259 -402 -534 -656 -772 -883 1625 406 24 0752 -084 -236 -378 -511 -638 -759 -877 1875 393 237 0808 -071 -219 -36 -495 -624 -749 -871 2125 382 233 0837 -063 -208 -348 -483 -614 -741 -867 2375 374 23 085 -058 -2 -339 -474 -606 -735 -863 2625 368 227 0855 -055 -195 -332 -467 -6 -731 -86 2875 363 225 0855 -053 -191 -328 -462 -596 -728 -858 3125 36 223 0853 -052 -189 -324 -459 -593 -725 -856 3375 357 221 0851 -051 -187 -322 -457 -59 -723 -855 3625 355 22 0849 -05 -186 -32 -455 -588 -722 -854 3875 354 219 0849 -049 -185 -319 -453 -587 -72 -853 4125 353 219 0849 -049 -184 -318 -452 -586 -72 -853 4375 353 219 0852 -049 -183 -317 -451 -585 -719 -852 4625 353 219 0855 -048 -183 -317 -451 -584 -718 middot852 4875 353 22 0861 -047 -182 -316 -45 -584 -718 -852 5125 354 22 0867 -047 -181 -315 -449 -584 -717 -851 5375 355 221 0875 -046 -181 -315 -449 -583 -717 -851 5625 356 222 0884 -045 -18 -314 -448 -582 -717 -851 5875 358 223 0894 -044 -179 -313 -448 -582 -716 -851 6125 359 225 0904 -043 -178 -313 -447 -582 -716 -851 6375 36 226 0915 -043 -177 -312 -447 -581 -716 -85
113
6625 362 227 0927 -042 -177 -311 -446 -581 -716 -85 6875 363 229 0939 -04 -176 -311 -445 -58 -715 -85 7125 365 23 0951 -039 -175 -31 -445 -58 -715 -85 7375 367 232 0964 -038 -174 -309 -444 -579 -715 -85 7625 368 233 0976 -037 -173 -308 -444 -579 -714 -85 7875 37 234 0989 -036 -172 -308 -443 -578 -714 -849 8125 371 236 1 -035 -171 -307 -442 -578 -714 -849 8375 373 237 101 -034 -17 -306 -442 -578 -713 -849 8625 375 239 103 -033 -169 -305 -441 -577 -713 -849 8875 376 24 104 -032 -168 -305 -441 -577 -713 -849 9125 378 241 105 -031 -168 -304 -44 -576 -712 -849 9375 379 243 106 -03 -167 -303 -439 -576 -712 -848 9625 381 244 107 -029 -166 -302 -439 -575 -712 -848 9875 382 245 109 -028 -165 -302 -438 -575 -712 -848 10125 384 246 11 -027 -164 -301 -438 -574 -711 -848 10375 385 248 111 -026 -163 -3 -437 -574 -711 -848 10625 386 249 112 -025 -163 -3 -437 -574 -711 -848 10875 387 25 113 -024 -162 -299 -436 -573 -711shy -848 11125 389 251 114 -023 -161 -298 -436 -573 -71 -848 11375 39 252 115 -022 -16 -298 -435 -573 -71 -847 11625 391 253 115 -022 -16 -297 -435 -572 -71 -847 11875 392 254 116 -021 -159 -297 -434 -572 -709 -847 12125 393 255 117 -02 -158 -296 -434 -572 -709 -847 12375 394 256 118 -019 -158 -296 -434 -571 -709 -847 12625 395 257 119 -019 -157 -295 -433 -571 -709 -847 12875 396 258 12 -018 -157 -295 -433 -571 -709 -847 13125 397 259 12 -017 -156 -294 -432 -57 -709 -847 13375 398 259 121 -017 -155 -294 -432 -57 -708 -847 13625 399 26 122 -016 -155 -293 -432 -57 -708 -846 13875 399 261 122 -016 -154 -293 -431 -57 -708 -846 14125 4 262 123 -015 -154 -292 -431 -569 -708 -846 14375 401 262 124 -015 -154 -292 -431 -569 -708 -846 14625 402 263 124 -014 -153 -292 -43 -569 -707 -846 14875 402 263 125 -014 -153 -291 -43 -569 -707 -846 15125 403 264 125 -013 -152 -291 -43 -569 -707 -846 15375 403 264 126 -013 -152 -291 -43 -568 -707 -846 15625 404 265 126 -012 -152 -291 -429 -568 -707 -846 15875 405 265 126 -012 -151 -29 -429 -568 -707 -846 16125 405 266 127 -012 -151 -29 -429 -568 -707 -846 16375 405 266 127 -011 -151 -29 -429 -568 -707 -846 16625 406 267 128 -011 -151 -29 -429 -568 -707 -846 16875 406 267 128 -011 -15 -289 -428 -568 -707 -845 17125 407 267 128 -01 -15 -289 -428 -567 -706 -845 17375 407 268 128 -01 -15 -289 -428 -567 -706 -845 17625 407 268 129 -01 -15 -289 -428 -567 -706 -845 17875 407 268 129 -01 -15 -289 -428 -567 -706 -845 18125 408 268 129 -01 -15 -289 -428 -567 -706 -845 18375 408 269 129 -01 -149 -289 -428 -567 -706 -845 18625 408 269 129 -001 -149 -288 -428 -567 -706 -845 18875 408 269 129 -001 -149 -288 -428 -567 -706 -845 19125 408 269 13 -001 -149 -288 -428 -567 -706 -845 19375 409 269 13 -001 -149 -288 -428 -567 -706 -845 19625 409 269 13 -001 -149 -288 -428 -567 -706 -845 19875 409 269 13 -001 -15 -288 -428 -567 -706 -845
114
FS Fresh Food Wan Simulation Output Including Anti-sweat Condenser Tube
INPUT PARAMETERS
Section Dimensions (mm) Hidth 4500 Length 2000 Depth 2960 Steel skin thickness 6500 Plastic skin thickness 2500
Mesh Geometry dx 2250 dy 2500 Number nodes in x-direction 20 Number nodes in y-direction 80 Number of steel skin nodes (including corner 00) 11 Steel nodes under the seal 2 to 10 Tube located at node 6
Steel skin conductivity (Him K) 5400 Foam insulation conductivity (Him K) 27000E-02 Plastic skin conductivity (Him K) 1500 Outside h (Hm2 K) 6870 Inside h (Hm2 K) 6700 Outside Temp (C) 2100 Inside Temp (C) 4000
OUPUT PARAMETERS
Number of iterations 602
10 Heat Flux Thru Hall (Hm2) 9132
Heat Transfer Along Metal Skin Under Seal node to node qm[Hm21 Qm[HI
2 3 -15052E+04 -2896 3 4 -15125E+04 -2910 4 5 -15198E+04 -2924 5 6 -15274E+04 -2939 6 7 3996 7688 7 8 3898 7500 8 9 3790 7292 9 10 3662 7045
Maximum difference () 1243
j qleft [HI qright [HI -1 -2957 7832 0 -92065E-02 -38838E-02 1 -77348E-02 -48044E-02 2 -51596E-02 -30284E-02 3 -32948E-02 -15188E-02 4 -1 9628E-02 -54201E-03 5 -98600E-03 16837E-03 6 -36442E-03 70ll8E-03 7 79586E-04 96757E-03 8 43478E-03 11452E-02 9 70118E-03 12340E-02 10 87877E-03 12340E-02
115
11 87879E-03 13228E-02 12 10564E-02 12340E-02 13 10564E-02 11452E-02 14 96759E-03 11452E-02 15 87877E-03 10564E-02 16 87879E-03 87877E-03 17 78999E-03 87877E-03 18 61238E-03 78999E-03 19 61240E-03 61237E-03 20 52359E-03 52358E-03 21 34598E-03 34598E-03 22 25719E-03 25717E-03 23 16838E-03 16839E-03 24 79586E-04 25 -98018E-04 26 -18681E-03 27 -27561E-03 28 -36442E-03 29 -54202E-03 30 -54202E-03 31 -7 1962E-03 32 -80842E-03 33 -8 9721E-03 34 -98602E-03 35 -10748E-02 36 -11636E-02 37 -12524E-02 38 -1 3412E-02 39 -1 4300E-02 40 -15188E-02 41 -1 5188E-02 42 -1 6076E-02 43 -16964E-02 44 -17852E-02 45 -1 7852E-02 46 -1 8740E-02 47 -19628E-02 48 -19628E-02 49 -19628E-02 50 -20516E-02 51 -21404E-02 52 -22292E-02 53 -22292E-02 54 -23180E-02 55 -23180E-02 56 -23180E-02 57 -24068E-02
79578E-04 -98018E-04 -1 8682E-03 -27561E-03 -45322E-03 -54202E-03 -71962E-03 -71962E-03 -8 9722E-03 -8 9722E-03 -10748E-02 -11636E-02 -12524E-02 -13412E-02 -14300E-02 -1 5188E-02 -16076E-02 -16964E-02 -16964E-02 -17852E-02 -18740E-02 -19628E-02 -20516E-02 -20516E-02 -21404E-02 -22292E-02 -22470E-02 -22381E-02 -22647E-02 -23358E-02 -23447E-02 -23802E-02 -24512E-02 -24690E-02
58 -23979E-02 -25223E-02 59 -24423E-02 60 -24246E-02 61 -24423E-02 62 -24779E-02 63 -25400E-02 64 -25400E-02 65 -25667E-02 66 -26199E-02 67 -26022E-02 68 -26111E-02 69 -26377E-02 70 -26022E-02 71 -26732E-02 72 -26821E-02 73 -26199E-02 74 -26643E-02
-25489E-02 -25755E-02 -25933E-02 -2 6199E-02 -26466E-02 -26643E-02 -26821E-02 -26910E-02 -27087E-02 -27265E-02 -27354E-02 -27443E-02 -27531E-02 -27620E-02 -27620E-02 -27709E-02
116
75 -26377E-02 -27709E-02 76 -26377E-02 -27709E-02 77 -26555E-02 -27709E-02 78 -26910E-02 -27620E-02 79 -26555E-02 -27620E-02
Qleft [ii] -3079 Qright [ii] 6756 Percent entering cabinet 1800
Fresh Food Nodal Temperatures (Condenser Tube)
x(mm) y(mm) 1125 3375 5625 7875 10125 12375 14625 16875 19125 21375
19875 126 1206 1154 1104 1055 1007 9608 9158 872 8294 19625 1259 1205 1153 1103 1054 1006 9602 9152 8715 8289 19375 1259 1205 1153 1102 1053 1006 9598 9149 8711 8285 19125 1259 1205 1153 1102 1053 1006 9596 9147 871 8284 18875 1259 1205 1153 1102 1053 1006 9596 9147 871 8284 18625 1259 1205 1153 1103 1054 1006 9599 915 8712 8286 18375 126 1206 1154 1103 1054 1007 9604 9154 8716 829 18125 1261 1207 1155 1104 1055 1007 9611 9161 8722 8295 17875 1263 1209 1156 1105 1056 1008 962 9169 873 8302 17625 1264 121 1158 1107 1058 101 9632 918 874 8311 17375 1266 1212 116 1109 1059 1011 9646 9193 8752 8322 17125 1269 1215 1162 1111 1061 1013 9663 9209 8766 8335 16875 1272 1217 1164 1113 1063 1015 9682 9226 8783 835 16625 1275 122 1167 1116 1066 1017 9704 9246 8801 8367 16375 1279 1224 117 1119 1069 102 9728 9269 8822 8386 16125 1282 1227 1174 1122 1072 1023 9755 9294 8845 8407 15875 1287 1231 1178 1126 1075 1026 9785 9322 887 843 15625 1292 1236 1182 113 1079 103 9818 9352 8898 8456 15375 1297 1241 1187 1134 1083 1034 9854 9385 8929 8484 15125 1302 1246 1192 1139 1088 1038 9892 9421 8962 8514 14875 1308 1252 1197 1144 1092 1042 9934 946 8998 8547 14625 1315 1258 1203 1149 1097 1047 9979 9502 9037 8583 14375 1322 1265 1209 1155 1103 1052 1003 9547 9078 8621 14125 1329 1272 1216 1162 1109 1058 1008 9595 9123 8662 13875 1337 1279 1223 1168 1115 1064 1014 9647 9171 8706 13625 1346 1287 1231 1176 1122 107 102 9703 9222 8753 13375 1355 1296 1239 1183 1129 1077 1026 9762 9277 8803 13125 1364 1305 1247 1191 1137 1084 1033 9824 9335 8856 12875 1374 1314 1256 12 1145 1092 104 9891 9396 8913 12625 1385 1325 1266 1209 1154 11 1047 9962 9462 8973 12375 1396 1335 1276 1219 1163 1109 1055 1004 9531 9037 12125 1408 1347 1287 1229 1173 1118 1064 1012 9605 9105 11875 1421 1359 1299 124 1183 1127 1073 102 9683 9176 11625 1434 1371 1311 1251 1194 1137 1082 1029 9765 9252 11375 1448 1385 1323 1263 1205 1148 1092 1038 9851 9332 11125 1462 1399 1336 1276 1217 1159 1103 1048 9943 9416 10875 1478 1413 135 1289 1229 1171 1114 1058 1004 9505 10625 1494 1429 1365 1303 1243 1184 1126 1069 1014 9598 10375 1511 1445 138 1318 1257 1197 1138 1081 1025 9696 10125 1528 1462 1397 1333 1271 121 1151 1093 1036 98 9875 1547 1479 1413 1349 1286 1225 1165 1106 1048 9908 9625 1566 1498 1431 1366 1302 124 1179 1119 106 1002
117
9375 1586 1517 145 1384 1319 1256 1194 1133 1073 1014 9125 1607 1537 1469 1402 1336 1272 1209 1147 1087 1027 8875 1629 1558 1489 1421 1355 129 1226 1163 1101 104 8625 1652 158 151 1441 1374 1308 1243 1179 1116 1054 8375 1676 1603 1532 1462 1394 1327 1261 1195 1131 1068 8125 17 1627 1555 1484 1415 1346 1279 1213 1148 1084 7875 1726 1652 1579 1507 1436 1367 1299 1231 1165 11 7625 1753 1678 1604 1531 1459 1389 1319 1251 1183 1116 7375 1781 1704 1629 1556 1483 1411 1341 1271 1202 1134 7125 1809 1732 1656 1581 1508 1435 1363 1292 1222 1152 6875 1839 1761 1684 1608 1533 146 1387 1314 1243 1172 6625 187 1791 1713 1636 156 1485 1411 1337 1264 1192 6375 1903 1823 1744 1666 1589 1512 1437 1362 1287 1214 6125 1936 1855 1775 1696 1618 1541 1464 1387 1312 1236 5875 197 1889 1808 1728 1649 157 1492 1414 1337 126 5625 2006 1923 1842 1761 1681 1601 1522 1443 1364 1285 5375 2043 196 1877 1795 1714 1633 1553 1473 1392 1312 5125 2081 1997 1914 1832 1749 1668 1586 1504 1422 134 4875 212 2036 1952 1869 1786 1704 1621 1538 1454 137 4625 2161 2076 1992 1909 1825 1741 1658 1573 1488 1403 4375 2203 2118 2034 195 1866 1782 1697 1611 1525 1437 4125 2246 2161 2077 1993 1909 1824 1738 1652 1564 1474 3875 229 2206 2123 2039 1955 1869 1783 1695 1606 1515 3625 2336 2253 217 2087 2003 1918 1831 1742 1651 1558 3375 2383 2302 222 2138 2055 197 1882 1793 1701 1606 3125 2432 2353 2273 2192 211 2026 1938 1848 1755 1658 2875 2482 2405 2328 225 217 2086 20 1909 1815 1715 2625 2533 2461 2387 2312 2234 2153 2067 1977 1881 178 2375 2586 2518 2449 2378 2304 2226 2142 2052 1955 1851 2125 264 2579 2516 2451 2381 2306 2225 2136 2039 1933 1875 2696 2642 2587 2529 2466 2396 2319 2232 2134 2026 1625 2753 2709 2664 2614 256 2497 2425 2341 2244 2133 1375 2811 278 2746 2708 2664 2611 2546 2468 2373 226 1125 2871 2854 2835 2811 278 2739 2685 2615 2524 2411 875 2932 2932 293 2923 2909 2885 2846 2787 2706 2595 625 2995 3014 3031 3045 3052 3049 3031 2989 2922 2824 375 3058 3098 3138 3175 3208 3234 3245 3223 3179 3109 125 3124 3185 3247 331 3373 3436 35 3483 3467 3451
x(mm) y(mm) 23625 25875 28125 30375 32625 34875 37125 39375 41625 43875
19875 7877 747 7071 6679 6294 5915 554 5168 4799 4432 19625 7872 7466 7067 6676 6291 5912 5538 5166 4798 4431 19375 7869 7463 7065 6674 6289 591 5536 5165 4797 443 19125 7868 7462 7063 6673 6288 591 5535 5165 4797 443 18875 7868 7462 7063 6673 6288 591 5535 5165 4796 443 18625 787 7463 7065 6674 6289 591 5536 5165 4797 443 18375 7873 7466 7067 6676 6291 5912 5537 5166 4797 443 18125 7878 747 7071 6679 6294 5914 5539 5167 4798 4431 17875 7884 7476 7076 6684 6298 5917 5542 5169 4799 4431 17625 7893 7483 7083 6689 6303 5921 5545 5172 4801 4432 17375 7903 7492 7091 6696 6309 5926 5549 5175 4803 4433 17125 7914 7503 71 6704 6316 5932 5553 5178 4806 4435 16875 7928 7515 7111 6714 6324 5939 5559 5182 4809 4436 16625 7943 7529 7123 6725 6333 5947 5565 5187 4812 4438 16375 796 7544 7137 6737 6343 5955 5572 5192 4815 444 16125 7979 7561 7152 675 6355 5965 558 5198 4819 4442
118
15875 8001 7581 7169 6765 6368 5976 5589 5205 4824 4445 15625 8024 7601 7188 6781 6382 5987 5598 5212 4829 4447 15375 8049 7624 7208 6799 6397 6 5608 522 4834 445 15125 8077 7649 723 6819 6414 6014 562 5229 484 4453 14875 8107 7676 7254 684 6432 603 5632 5238 4847 4457 14625 8139 7705 728 6862 6451 6046 5645 5248 4854 4461 14375 8174 7737 7308 6887 6472 6064 566 5259 4861 4465 14125 8211 777 7338 6913 6495 6083 5675 5271 4869 4469 13875 8251 7806 737 6941 6519 6103 5691 5283 4878 4474 13625 8294 7845 7405 6972 6545 6125 5709 5297 4887 4479 13375 834 7886 7441 7004 6573 6148 5728 5311 4897 4484 13125 8388 793 748 7038 6603 6173 5748 5326 4907 449 12875 844 7977 7522 7075 6634 62 5769 5343 4918 4496 12625 8495 8026 7566 7114 6668 6228 5792 536 493 4502 12375 8553 8079 7613 7155 6703 6258 5816 5378 4943 4509 12125 8615 8135 7663 7199 6741 6289 5842 5398 4956 4517 11875 868 8194 7716 7245 6781 6323 5869 5418 4971 4524 11625 8749 8256 7771 7294 6823 6358 5898 544 4986 4532 11375 8822 8322 783 7346 6868 6396 5928 5463 5002 4541 11125 8899 8392 7892 7401 6915 6435 596 5488 5018 455 10875 898 8465 7958 7458 6965 6477 5994 5514 5036 456 10625 9066 8542 8027 7519 7018 6521 6029 5541 5055 457 10375 9155 8624 81 7583 7073 6568 6067 557 5075 4581 10125 925 8709 8177 7651 7131 6617 6107 56 5095 4592 9875 9349 8799 8257 7722 7193 6669 6149 5632 5117 4604 9625 9454 8894 8342 7797 7257 6723 6193 5665 514 4617 9375 9564 8994 8431 7875 7325 678 6239 5701 5165 463 9125 9679 9098 8525 7958 7397 684 6288 5738 519 4644 8875 98 9208 8624 8045 7472 6904 6339 5777 5217 4659 8625 9927 9324 8727 8137 7551 6971 6393 5819 5246 4674 8375 1006 9445 8836 8233 7635 7041 645 5862 5276 4691 8125 102 9572 895 8334 7722 7115 651 5908 5307 4708 7875 1035 9706 907 844 7814 7192 6573 5956 5341 4726 7625 105 9846 9197 8552 7911 7274 664 6007 5376 4745 7375 1066 9994 933 867 8014 7361 671 6061 5413 4766 7125 1083 1015 947 8794 8121 7452 6784 6118 5452 4787 6875 1101 1031 9617 8925 8235 7548 6862 6178 5494 481 6625 112 1049 9773 9063 8356 765 6945 6241 5537 4834 6375 114 1067 9937 9209 8483 7757 7033 6308 5584 4859 6125 1161 1086 1011 9364 8618 7872 7126 638 5634 4887 5875 1183 1106 103 9528 8761 7993 7225 6456 5686 4916 5625 1207 1128 1049 9703 8914 8123 7331 6537 5743 4947 5375 1231 1151 107 9889 9076 8261 7443 6624 5803 498 5125 1258 1175 1092 1009 925 8409 7564 6717 5867 5015 4875 1286 1201 1116 103 9436 8567 7694 6816 5936 5053 4625 1316 1229 1142 1053 9637 8738 7833 6924 601 5094 4375 1349 1259 1169 1078 9853 8922 7983 7039 609 5138 4125 1384 1292 1199 1104 1009 912 8146 7164 6177 5186 3875 1422 1327 1231 1133 1034 9336 8321 7299 627 5237 3625 1463 1365 1266 1165 1062 957 8512 7445 637 5291 3375 1508 1407 1304 1199 1092 9824 8719 7603 6479 middot535 3125 1557 1453 1346 1237 1124 101 8943 7773 6595 5412 2875 1612 1504 1393 1278 116 104 9185 7956 6719 5478 2625 1673 1561 1444 1323 1199 1073 9446 8152 6851 5546 2375 1741 1624 1501 1373 1242 1108 9725 8359 6989 5617 2125 1818 1695 1565 1429 1289 1146 1002 8575 713 5687 1875 1906 1775 1636 149 1339 1186 1032 8792 727 5755 1625 2007 1868 1716 1556 1392 1227 1062 9001 7401 5818
119
1375 1125 875 625 375 125
2127 2271 2449 2679 2994 3436
1975 2103 226
2467 2776 3361
1807 1912 2032 2173 2333 2469
1629 1707 1788 1863 191
1868
1447 1501 1548 1575 1559 1454
1266 1301 1324 1324 1279 1163
109 1111 112
1107 1058 9548
9183 9311 934
9205 8813 8043
7514 7591 7611 7544 735
6956
5873 5918 5953 5988 6049 6199
F6 Freezer Wall Simulation Output Including Anti-sweat Condenser Tube
INPUT PARAMETERS
Section Dimensions (mm) Width Length Depth Steel skin thickness Plastic skin thickness
5600 2000 1580 6500 2500
Mesh Geometry dx dy Number nodes in x-direction Number nodes in y-direction Number of steel skin nodes (including corner 00) Steel nodes under the seal Tube located at node
2800 2500 20 80
11 2 to 10 6
Steel skin conductivity (Wm K)
Foam insulation conductivity (Wm K) Plastic skin conductivity (Wm K)
Outside h (Wm2 K) Inside h (Wm2 K) Outside Temp (C) Inside Temp (C)
5400 27000E-02 1500 6870 6410 2100 -1000
OUPUT PARAMETERS
Number of iterations 879
ID Heat Flux Thru Wall (Wm2) 1362
Heat Transfer Along Metal Skin Under Seal node to node qm[Wm2] Qm[W]
2 3 -15024E+04 -1543 3 4 -15111E+04 -1552 4 5 -15205E+04 -1562 5 6 -15310E+04 -1572 6 7 5828 5986 7 8 5690 5844 8 9 5535 5684 9 10 5348 5492
Maximum difference (Is) 1356
j qleft[W] qright[W] -1 -1566 5928
120
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63
0 -62085E-02 -31363E-02 -5 9522E-02 -40097E-02 -44286E-02 -30955E-02 -33621E-02 -21814E-02 -25242E-02 -1 4577E-02 -1 8767E-02 -9 6252E-03 -13815E-02 -58162E-03 -10387E-02 -31499E-03 -73398E-03 -1 6265E-03 -54353E-03 -10285E-04
-35309E-03 27805E-04 -23882E-03 65891E-04 -16265E-03 14208E-03 -1 24 55E-03 14207E-03 -48371E-04 14207E-03 -10285E-04 10398E-03 -10285E-04 10399E-03 -10281E-04 10398E-03 -48371E-04 65891E-04 -1 02 85E-04 27805E-04 -86465E-04 16377E-04 -48375E-04 -52182E-04 -86465E-04 -97886E-04 -1 2455E-03 -13979E-03 -1 7788E-03 -16645E-03 -19692E-03 -21597E-03 -24263E-03 -25786E-03 -30357E-03 -30357E-03 -33404E-03 -35309E-03 -3 7975E-03 -3 9879E-03 -41784E-03 -44450E-03 -45974E-03 -49402E-03 -50164E-03 -53592E-03 -54353E-03 -58162E-03 -58543E-03 -62733E-03 -62733E-03 -66923E-03 -66542E-03 -71493E-03 -70351E-03 -75303E-03 -74541E-03 -7 9111E-03 -77969E-03 -83301E-03 -81397E-03 -87491E-03 -85206E-03 -90919E-03 -88634E-03 -94728E-03 -92062E-03 -97775E-03 -95109E-03 -10158E-02 -98537E-03 -10463E-02 -1 0158E-02 -10768E-02 -1 04 63E-02 -11073E-02 -10692E-02 -11377E-02 -10996E-02 -11644E-02 -11225E-02 -1 1949E-02 -11492E-02 -12215E-02 -11758E-02 -12444E-02 -11949E-02 -12672E-02 -12177E-02 -12901E-02 -12368E-02 -13129E-02 -12596E-02 -1 3282E-02 -12748E-02 -1 351 OE-02 -1 2977E-02 -13701E-02 -13129E-02 -1 3853E-02 -13282E-02 -14005E-02 -1 3434E-02 -14158E-02 -13586E-02 -14310E-02 -1 3701E-02 -14463E-02
121
64 -1 3815E-02 -1 4577E-02 65 -1 392 9E-02 -14691E-02 66 -14005E-02 -14767E-02 67 -14120E-02 -14881E-02 68 -14196E-02 -14958E-02 69 -1 4272E-02 -15034E-02 70 -14310E-02 -15110E-02 71 -1 4386E-02 -1 5148E-02 72 -14424E-02 -15186E-02 73 -14463E-02 -15224E-02 74 -14501E-02 -1 5262E-02 75 -14501E-02 -1 5300E-02 76 -14539E-02 -15262E-02 77 -14539E-02 -15300E-02 78 -1 4539E-02 -15262E-02 79 -14501E-02 -1 5300E-02
Qleft [Wj -1653 Qright [Wj 5163 Percent entering cabinet 2380
Freezer Nodal Temperatures (Condenser Tube)
x(mm) y(mm) 14 42 70 98 126 154 182 210 238 266
19875 9606 8457 7334 6235 516 4107 3075 2064 107 00944 19625 9596 8448 7325 6227 5152 4099 3068 2056 1064 00882 19375 9591 8443 732 6222 5148 4095 3064 2053 106 00850 19125 9591 8443 732 6222 5147 4095 3064 2052 106 00847 18875 9596 8448 7325 6226 5151 4099 3067 2056 1063 00873 18625 9606 8457 7334 6235 5159 4106 3074 2062 1069 00928 18375 9621 8472 7347 6248 5171 4118 3085 2072 1078 01013 18125 9641 8491 7366 6265 5188 4133 3099 2085 109 01128 17875 9666 8514 7388 6287 5208 4152 3117 2102 1106 01272 17625 9696 8543 7416 6313 5233 4176 3139 2123 1125 01447 17375 9731 8577 7448 6343 5262 4203 3165 2147 1147 01652 17125 9772 8616 7485 6378 5295 4234 3194 2174 1173 01888 16875 9817 8659 7526 6418 5333 427 3228 2206 1202 02156 16625 9868 8708 7573 6462 5375 431 3265 224 1234 02455 16375 9924 8762 7624 6511 5421 4353 3306 2279 127 02786 16125 9985 8821 7681 6565 5472 4402 3352 2322 131 03149 15875 1005 8885 7742 6624 5528 4454 3401 2368 1353 03546 15625 1012 8954 7809 6687 5588 4511 3455 2418 1399 03976 15375 102 9029 7881 6755 5653 4573 3513 2472 145 04441 15125 1029 911 7958 6829 5723 4639 3575 253 1504 0494 14875 1038 9196 804 6907 5798 4709 3641 2592 1562 05474 14625 1047 9287 8128 6991 5877 4784 3712 2659 1623 06045 14375 1057 9385 8221 708 5962 4865 3787 2729 1689 06652 14125 1068 9488 832 7175 6052 495 3868 2804 1759 07297 13875 1079 9597 8424 7275 6147 504 3952 2884 1833 07981 13625 1091 9713 8535 738 6247 5135 4042 2968 1911 08704 13375 1104 9834 8651 7491 6353 5235 4136 3056 1993 09466 13125 1117 9962 8774 7608 6464 534 4236 315 208 1027 12875 1131 101 8902 7731 6581 5451 434 3248 2172 1112 12625 1146 1024 9037 786 6704 5568 445 3351 2268 1201 12375 1161 1038 9178 7995 6833 569 4566 3459 2369 1294
122
12125 1177 1054 9326 8136 6967 5818 4686 3572 2475 1392 11875 1194 107 9481 8284 7108 5951 4813 3691 2585 1494 11625 1211 1087 9642 8439 7256 6091 4945 3815 2701 1602 11375 1229 1104 981 86 7409 6237 5083 3945 2822 1714 11125 1248 1122 9985 8768 757 639 5227 4081 2949 1832 10875 1268 1141 1017 8943 7737 6549 5378 4222 3082 1954 10625 1288 1161 1036 9125 7911 6714 5534 437 322 2083 10375 1309 1181 1055 9314 8092 6887 5698 4524 3364 2217 10125 1331 1203 1076 9511 8281 7067 5868 4685 3514 2356 9875 1354 1225 1097 9716 8477 7254 6046 4852 3671 2502 9625 1378 1248 1119 9929 8681 7448 6231 5026 3835 2654 9375 1402 1271 1142 1015 8893 7651 6423 5208 4005 2813 9125 1428 1296 1166 1038 9113 7861 6623 5398 4183 2979 8875 1454 1321 1191 1062 9342 808 6832 5595 4369 3152 8625 1481 1348 1216 1086 9579 8308 7049 5801 4562 3333 8375 1509 1375 1243 1112 9826 8545 7275 6015 4764 3522 8125 1538 1403 127 1139 1008 8791 751 6238 4975 3719 7875 1568 1432 1299 1166 1035 9047 7755 6472 5196 3925 7625 1598 1462 1328 1195 1063 9314 8011 6715 5426 4142 7375 163 1494 1358 1224 1091 9591 8278 697 5667 4368 7125 1663 1526 139 1255 1121 9881 8556 7236 5919 4606 6875 1697 1559 1422 1287 1152 1018 8847 7514 6184 4855 6625 1731 1593 1456 132 1185 105 9151 7806 6462 5118 6375 1767 1629 1491 1355 1218 1083 9469 8113 6755 5394 6125 1804 1665 1527 139 1254 1117 9804 8435 7063 5686 5875 1842 1703 1565 1428 129 1153 1015 8774 7388 5995 5625 1881 1742 1604 1466 1329 1191 1052 9133 7732 6322 5375 1921 1782 1644 1507 1369 1231 1091 9511 8097 6669 5125 1962 1824 1686 1549 1411 1272 1133 9913 8485 7039 4875 2004 1867 173 1593 1455 1317 1176 1034 8899 7435 4625 2047 1912 1776 164 1502 1363 1223 108 9341 7859 4375 2092 1958 1823 1688 1552 1413 1272 1128 9816 8315 4125 2138 2005 1873 1739 1604 1466 1325 1181 1033 8807 3875 2184 2055 1925 1793 166 1523 1382 1238 1088 934 3625 2232 2106 1979 1851 1719 1584 1444 1299 1148 992 3375 2282 216 2037 1911 1783 1649 1511 1366 1214 1055 3125 2332 2215 2097 1976 1851 1721 1584 1439 1286 1125 2875 2384 2273 2161 2045 1925 1798 1663 152 1366 1202 2625 2436 2334 2229 212 2005 1883 1751 1609 1455 1288 2375 249 2397 2301 22 2093 1976 1849 1708 1554 1384 2125 2546 2463 2377 2287 2188 2079 1957 182 1666 1493 1875 2602 2532 2459 238 2293 2193 2079 1946 1793 16 17 1625 266 2605 2546 2482 2407 232 2215 2089 1939 176 1375 2719 2681 264 2592 2533 2461 2369 2253 2108 1928 1125 2779 2761 2739 271 2671 2618 2543 244 2305 2128 875 2841 2844 2844 2838 2822 2792 2739 2655 2535 2367 625 2903 293 2954 2974 2986 2984 2959 2899 2802 2658 375 2967 3018 3069 3117 316 3194 3209 3173 3108 3009 125 3032 3108 3186 3263 3342 3421 35 347 344 3412
x (nun) y (nun) 294 322 350 378 406 434 462 490 518 546
19875 -0865 -1811 -2743 -3663 -4573 -5474 -6368 -7257 -8141 -9022 19625 -0871 -1816 -2747 -3667 -4577 -5477 -6371 -7259 -8142 -9024 19375 -0874 -1819 -275 -3669 -4578 -5479 -6372 -726 -8143 -9024 19125 -0874 -1819 -275 -367 -4579 -5479 -6372 -726 -8144 -9025 18875 -0872 -1817 -2748 -3668 -4577 -5478 -6372 -7259 -8143 -9025
123
18625 -0867 -1812 -2744 -3664 -4574 -5476 -637 -7258 -8142 -9024 18375 -0859 -1805 -2738 -3659 -457 -5472 -6366 -7256 -8141 -9023 18125 -0848 -1796 -273 -3652 -4563 -5466 -6362 -7252 -8139 -9022 17875 -0835 -1784 -2719 -3642 -4555 -546 -6357 -7248 -8136 -9021 17625 -0819 -1769 -2706 -3631 -4546 -5451 -635 -7243 -8132 -9019 17375 -0800 -1752 -2691 -3618 -4534 -5442 -6342 -7237 -8128 -9017 17125 -0779 -1733 -2673 -3602 -4521 -5431 -6334 -7231 -8124 -9014 16875 -0754 -1711 -2654 -3585 -4506 -5418 -6323 -7223 -8119 -9012 16625 -0727 -1686 -2632 -3565 -4489 -5404 -6312 -7214 -8113 -9009 16375 -0697 -1659 -2607 -3544 -447 -5389 -6299 -7205 -8106 -9005 16125 -0664 -1629 -258 -352 -445 -5371 -6286 -7194 -8099 -9001 15875 -0627 -1596 -2551 -3494 -4428 -5353 -6271 -7183 -8091 -8997 15625 -0588 -156 -2519 -3466 -4404 -5332 -6254 -717 -8083 -8993 15375 -0545 -1522 -2484 -3436 -4377 -531 -6236 -7157 -8074 -8988 15125 -0500 -148 -2447 -3403 -4349 -5287 -6217 -7143 -8064 -8983 14875 -0451 -1436 -2408 -3368 -4319 -5261 -6197 -7127 -8053 -8977 14625 -0399 -1388 -2365 -3331 -4287 -5234 -6175 -7111 -8042 -8971 14375 -0343 -1338 -232 -3291 -4253 -5206 -6152 -7093 -803 -8965 14125 -0284 -1284 -2272 -3249 -4216 -5175 -6127 -7074 -8017 -8958 13875 -0221 -1228 -2221 -3204 -4177 -5143 -6101 -7054 -8004 -8951 13625 -0155 -1168 -2168 -3157 -4137 -5108 -6073 -7033 -7989 -8943 13375 -0085 -1104 -2111 -3107 -4093 -5072 -6044 -7011 -7974 -8935 13125 -0011 -1037 -2051 -3054 -4048 -5034 -6013 -6987 -7958 -8927 12875 0065 -0966 -1988 -2998 -4 -4993 -598 -6963 -7941 -8918 12625 01474 -0892 -1922 -294 -3949 -4951 -5946 -6937 -7924 -8909 12375 0233 -0815 -1852 -2878 -3896 -4906 -591 -6909 -7905 -8899 12125 03229 -0733 -1779 -2814 -384 -4859 -5872 -688 -7885 -8888 11875 0417 -0648 -1702 -2746 -3782 -481 -5832 -685 -7865 -8877 11625 05157 -0558 -1622 -2675 -372 -4758 -5791 -6819 -7843 -8866 11375 06189 -0464 -1537 -2601 -3656 -4704 -5747 -6785 -7821 -8854 11125 07269 -0366 -1449 -2523 -3589 -4648 -5701 -675 -7797 -8841 10875 08398 -0263 -1357 -2441 -3518 -4588 -5653 -6714 -7772 -8828 10625 09577 -0156 -126 -2356 -3444 -4526 -5603 -6676 -7746 -8814 10375 1081 -0044 -116 -2267 -3367 -4461 -555 -6636 -7718 -88 10125 121 00732 -1054 -2174 -3286 -4393 -5495 -6594 -769 -8785 9875 1344 01957 -0943 -2076 -3202 -4322 -5437 -655 -766 -8769 9625 1484 03238 -0828 -1974 -3113 -4247 -5377 -6504 -7628 -8752 9375 1631 04575 -0708 -1867 -302 -4169 -5314 -6456 -7596 -8734 9125 1784 05974 -0582 -1755 -2923 -4087 -5247 -6405 -7561 -8716 8875 1944 07436 -0450 -1638 -2822 -4001 -5178 -6352 -7525 -8697 8625 2111 08966 -0312 -1516 -2715 -3911 -5105 -6296 -7487 -8676 8375 2286 1057 -0167 -1387 -2604 -3817 -5028 -6238 -7447 -8655 8125 2469 1224 -0015 -1253 -2486 -3718 -4948 -6177 -7405 -8633 7875 2661 14 0143 -1111 -2363 -3614 -4863 -6112 -736 -8609 7625 2861 1584 031 -0962 -2234 -3504 -4774 -6044 -7314 -8584 7375 3072 1778 04856 -0806 -2097 -3389 -468 -5972 -7265 -8558 7125 3293 1982 06704 -0641 -1954 -3267 -4581 -5896 -7213 -853 6875 3526 2196 08652 -0467 -1802 -3138 -4476 -5816 -7158 -8501 6625 3771 2422 1071 -0283 -1641 -3002 -4366 -5732 -71 -847 6375 403 2661 1288 -0089 -1471 -2858 -4248 -5642 -7038 -8437 6125 4303 2914 1519 01168 -1291 -2705 -4124 -5547 -6973 -8402 5875 4593 3182 1763 03357 -11 -2542 -3991 -5445 -6904 -8365 5625 49 3467 2023 05686 -0896 -2369 -385 -5338 -683 -8326 5375 5227 3771 23 08169 -0678 -2185 -37 -5223 -6751 -8284 5125 5576 4095 2596 1082 -0446 -1988 -354 -5101 -6668 -8239 4875 5949 4442 2913 1366 -0198 -1778 -337 -4971 -6579 -8193 4625 635 4814 3254 167 00669 -1553 -3187 -4832 -6485 -8143 4375 6781 5215 3619 1997 03519 -1313 -2993 -4685 -6385 -809
124
4125 7246 5647 4014 2349 06577 -1055 -2785 -4528 -6279 -8036 3875 775 6116 444 2728 0986 -0780 -2565 -4362 -6168 -7978 3625 8299 6625 4902 3137 1339 -0486 -233 -4187 -6051 -7919 3375 8899 718 5404 3579 1717 -0173 -2082 -4003 -593 -7859 3125 9558 7787 595 4057 2122 01586 -1823 -3813 -5806 -7798 2875 1028 8455 6545 4573 2555 0508 -1553 -3618 -568 -7739 2625 1109 9192 7197 513 3014 0872 -1277 -3422 -5558 -7683 2375 12 1001 7912 5729 3497 1245 -1002 -3233 -5442 -7633 2125 1301 1093 8698 6373 3998 1618 -0739 -3059 -534 -7592 1875 1418 1196 9566 7058 4508 1975 -0503 -2914 -5262 -7564 1625 1552 1314 1053 778 5007 2292 -0319 -2818 -5218 -7554 1375 171 1452 116 8525 5462 2528 -0224 -2798 -5226 -7564 1125 19 1616 1281 9263 5815 2621 -0272 -2892 -5304 -7597 875 2136 182 1417 9928 5968 2477 -0537 -3151 -5478 -7651 625 244 2095 1569 1037 575 1953 -112 -3637 -5773 -7713 375 2845 2514 1726 1027 4873 0854 -2146 -4427 -6224 -7757 125 3384 3296 1814 8879 2904 -1057 -3745 -5602 -6885 -7725
F bull 7 Seal Simulation Source Code and Ouput
Program Seal
c This program simulates the heat transfer characteristics of an c idealized refrigerator door gasket The steady-state temperature c profile is determined numerically from a 2-D finite difference c code
cxxxxxxxxxxxxx Parameters and Variablesxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
integer NNNWnsurfijjlloopiters real emmissigmakhihoTiTodelsNN real depthareatolkair
parameter (N=6) parameter (NN=20) parameter (W=7) parameter (nsurf=4N-l) parameter (emmis=09) parameter (sigma=567e-8) parameter (k=03) parameter (kair=0026) parameter (hi=641) parameter (ho=687) parameter (Ti=1032) parameter (To=209) parameter (sNN=02) parameter (del=sNNNN) parameter (depth=10) parameter (area=deldepth) parameter (tol=10)
real x(Onsurf)y(Onsurf)len(ONOnsurf) real F(OnsurfOnsurf) real T(-lNN+lONN)radl(nsurf+l)rad(Onsurf) real Eb(Onsurf)bvector(nsurf+l)Amatrix(nsurf+lnsurf+l) real difasumqsumqtotqin(NN-l) real rlr2r3r4r5
125
real clc2c3c4c5c6c7
open (lfilemiddotGasketoutposition-rewind) open (2file=Gasket(q)outpositionmiddotrewind)
cxxxxxxxxxxxxx Determine Viewfactors xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
call Points(Ndelnsurfxy) call length(Ndelnsurfxylen) call Vfactor(NdelnsurflenF)
cxxxxxxxxxxxxx Resistors (C-m2W)
c Interior x- and y-directions rl=delk
c Exterior to outdoor ambient r2=1ho
c Exterior to indoor ambient r3-1hi
c Radiation r4=(1-emmis)emmis
c Air r5=delkair
xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
cxxxxxxxxxxxxx Guass-Siedel Iteration xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
c Begin massive loop to determine the steady-state temperature c distribution across the section First update the interior nodes c by considering the radiative heat transfer among the interior c surfaces The radiative transfer is updated by calling a routine c which computes the new radiosities every iteration Loop until c tolerance is met
c Initialize temperature field do 10 i=ONN
do 11 jONN T(ij)=50
11 continue 10 continue
do 15 j=ONN T(-1j)=250 T(NN+lj)=50
15 continue
c Set temperatures for row y=O and row y=NN do 20 i=ONN
T(iO)=fl(idel) T(iNN)=f2(idel)
20 continue
cxxxxxxxxxxxxx Begin Iteration xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
loop=l iters=l do while (loop eq 1)
c Update radiosities using new temps and update interior surface nodes
call Jsolver(FemmissigmaTNNNWnsurfradlradEb + bvectorAmatrix)
c interior corners cl=area (2rl) c2=arearl
126
c3=area (2rl) c4=arearl c5=arear4 c6=1(cl+c2+c3+c4)
T(WW)=c6(clT(W+lW)+c2T(W-lW)+c3T(WW+l)+ + c4T(WW-l)+c5(rad(0)-Eb(0raquo)
cl=arearl c2=area(2rl) c3=area(2rl) c4=arearl c5=arear4 c6-1(cl+c2+c3+c4) T(W+NW)=c6(clT(W+N+lW)+c2T(W+N-lW)+c3T(W+NW+l)+
+ c4T(W+NW-l)+c5(rad(N)-Eb(Nraquo) clarearl c2-area (2rl) c3-arearl c4=area(2rl) c5=arear4 c6=1(cl+c2+c3+c4) T(W+NW+N)=c6 (clT(W+N+lW+N)+c2T(W+N-lW+N) +c3T(W+NW+N+l)+
+ c4T(W+NW+N-l)+c5(rad(2N)-Eb(2Nraquo) cl=area(2rl) c2=arearl c3=arearl c4=area(2rl) c5=arear4 c6=1(cl+c2+c3+c4) T(WW+N)=c6 (clT(W+lW+N) +c2T(W-lW+N)+c3T(WW+N+l) +
+ c4T(WW+N-l)+c5(rad(3N)-Eb(3Nraquo)
c Interior surface y=W jl=l do 22 i=W+lW+N-l
cl=area(2rl) c2=area (2rl) c4=arearl c5=arear4 c7=arear5 c6=1(cl+c2+c4+c7) T(iW)=c6(clT(i+lW)+c2T(i-lW)+
+ c7T(iW+l)+c4T(iW-l)+c5(rad(jl)-Eb(jlraquo) jl=j1+1
22 continue
c Interior surface y=N+W jl=3N-l do 25 i=W+lW+N-l
cl=area(2rl) c2=area (2rl) c3=arearl c5=arear4 c7=arear5 c6=1(cl+c2+c3+c7) T(iW+N)=c6(clT(i+lW+N)+c2T(i-lW+N)+
+ c7T(iW+N-l)+c3T(iW+N+l)+c5(rad(jl)-Eb(jlraquo) jl=jl-l
25 continue
c interior surface x=W jl=4N-l do 30 j=W+lW+N-l
c2=arearl
127
c3=area (2rl) c4=area(2rl) c5-arear4 c7-arear5 c6-1(c2+c3+c4+c7) T(Wj)-c6(c7T(W+lj)+c2T(W-lj)+c3T(Wj+l)+
+ c4T(Wj-l)+c5(rad(jl)-Eb(jl))) jl=jl-l
30 continue
c interior surface x=W+N jl=N+l do 35 j-W+lW+N-l
cl=arearl c3=area(2rl) c4=area (2rl) c5-arear4 c7-arear5 c6-1(cl+c3+c4+c7) T(W+Nj)=c6(clT(W+N+lj)+c7T(W+N-lj)+c3T(W+Nj+l)+
+ c4T(W+Nj-l)+c5(rad(jl)-Eb(jl))) jl=j1+1
35 continue
c Interior air nodes do 37 j=W+lN+W-l
do 38 i=W+lN+W-l call sseqn(Tr5r5r5r5areaareaareaareaijNN)
38 continue 37 continue
c Solid nodes do 40 i=lNN-l
do 45 jlW-l call sseqn(TrlrlrlrlareaareaareaareaijNN)
45 continue do 50 j=W+N+lNN-l
call sseqn(TrlrlrlrlareaareaareaareaijNN) 50 continue 40 continue
do 55 j=WW+N do 60 i=lW-l
call sseqn(TrlrlrlrlareaareaareaareaijNN) 60 continue
do 65 i=W+N+lNN-l call sseqn(TrlrlrlrlareaareaareaareaijNN)
65 continue 55 continue
c Side boundaries do 70 j=lNN-l
call sseqn(Trlr2rlrlareaareaarea2area20jNN) call sseqn(Tr3rlrlrlareaareaarea2area2NNjNN)
70 continue
c Apply energy balance around the boundary of the gasket to determine c stopping criterium dif
dif-OO dif=dif+(area(2rl))(T(00)-T(01)) dif=dif+(area(2rl))(T(0NN)-T(0NN-l)) do 90 i=lNN-l
dif=dif+(arearl)(T(iO)-T(il)) dif=dif+(arearl)(T(iNN)-T(iNN-l))
128
90 continue dif=dif+(area(2r1raquo(T(NN0)-T(NN1raquo dif=dif+(area(2r1raquo(T(NNNN)-T(NNNN-1raquo
do 95 j=1NN-1 dif=dif+(arear2)(To-T(0jraquo dif-dif+(arear3)(Ti-T(NNjraquo
95 continue
print dif
c Stopping criterium if (dif It toll then
loop-O endif if (iters eq 10000) then
loop=O endif
iters=iters+1 end do
cxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx c Compute heat flux into the cabinet
qsum=OO asum=OO do 97 j=1NN-1
qin(j)=hiarea(T(NNj)-Ti) qsum=qsum+qin(j) asum=asum+area
97 continue qtot=qsumasum write(2) heat flux to interior [Wm2)qtot
do 100 j=NNO-l write(l) (T(ij)i=ONN)
100 continue
pause stop end
c----------------------------------------------------------------------shyc------~----------------------------------------------------------------
Subroutine Points(Ndelnsurfxy)
integer Nnsurfi real delincrx(Onsurf)y(Onsurf)
x(O)=OO y(0)=del2
c Points along y=O edge incr-OO do 10 i=lN
y(i)=OO x(i)=(del2)+incr incr=incr+del
10 continue
c Points along x=Ndel edge incr=OO do 20 i=N+12N
x(i)=Ndel
129
y(i)-(del2)+incr incr-incr+del
20 continue
c Points along y=Ndel edge incr=OO do 30 i=3N2N+l-1
y(i)-Ndel x(i)=(del2)+incr incr-incr+del
30 continue
c Points along x-O edge incr=OO do 40 i-nsurf3n+l-1
xli) -00 y(i)-laquo3del)2)+incr incr-incr+del
40 continue
return end
c----------------------------------------------------------------------shyc-----------------------------------------------------------------------
Subroutine length(Ndelnsurfxylen)
integer Nnsurfij real dellen(ONOnsurf)x(Onsurf)y(Onsurf)
c Special case surface 0 do 10 j=Onsurf
len(0j)=sqrtlaquox(0)-x(jraquo2+(y(0)-y(jraquo2) 10 continue
c Surfaces along y=O do 20 i=IN-l
do 30 j=Onsurf len(ij)=sqrtlaquox(i)-x(jraquo2+(y(i)-y(jraquo2)
30 continue 20 continue
c Special case surface N do 50 j=Onsurf
len(Nj)=sqrtlaquox(N)-x(jraquo2+(y(N)-y(jraquo2) 50 continue
return end
c----------------------------------------------------------------------shyc-----------------------------------------------------------------------
Subroutine Vfactor(NdelnsurflenF)
integer Nnsurfijjlj2 real dellen(ONOnsurf)F(OnsurfOnsurf)Lzero
c Determine viewfactors for special case of surface 0 Lzero=delsqrt(20) do 10 j=Onsurf
if (j eq 0) then F(Oj)=OO
elseif (j eq nsurf) then F(Oj)=(len(Oj)+len(10)-len(00)-len(ljraquo(2Lzero)
else F(0j)=(len(0j)+len(lj+l)-len(Oj+l)-len(ljraquo(2Lzero)
130
endif 10 continue
c Determine viewfactors for surfaces on edge y-O
do 20 i=IN-l do 30 j=Onsurf
if (i eq j) then F(ij)=OO
elseif (j eq nsurf) then F(ij)=(len(ij)+len(i+l0)-len(i0)-len(i+ljraquo(2de1)
else F(ij)=(len(ij)+len(i+lj+l)-len(ij+l)-len(i+ljraquo(2del)
endif sum=sum+F(ij)
30 continue 20 continue
c Determine viewfactors for all other surfaces do 40 iON-l
do 50 j=03N-l F(i+Nj+N)=F(ij)
50 continue do 60 j=3Nnsurf
F(i+Nj-3N)=F(ij) 60 continue
do 70 j=02N-1 F(i+2Nj+2N)=F(ij)
70 continue do 80 j=2Nnsurf
F(i+2Nj-2N)=F(ij) 80 continue
do 90 j=ON-l F(i+3Nj+3N)=F(ij)
90 continue do 100 j=Nnsurf
F(i+3Nj-N)=F(ij) 100 continue
40 continue
return end
c----------------------------------------------------------------------shyc-----------------------------------------------------------------------
Subroutine Jsolver(FemmissigmaTNNNWnsurfradlradEb + bvectorAmatrix)
integer NNNnsurfij real emmissigmaF(OnsurfOnsurf) real T(-INN+10NN)rad1(nsurf+l)rad(0nsurf) real Eb(0nsurf)bvector(nsurf+1)Amatrix(nsurf+lnsurf+l)surn
c Compute Eb for all surfaces do 10 i-ON-l
Eb(i)=sigma(T(i+WW) 4) Eb(i+N)=sigma(T(W+Ni+W)4)
10 continue incr=W+N do 20 i=0N-1
Eb(i+2N)=siqrna(T(incrW+N) 4) Eb(i+3N)=sigma(T(Wincr)4) incr=incr-1
20 continue
131
c Assign values to vector b do 30 i=Onsurf
bvector(i+l)-(emmis(l-emmisraquoEb(i) 30 continue
c Assign values to matrix A do 40 i-Onsurf
do SO j=Onsurf Amatrix(i+lj+l)--F(ij)
SO continue 40 continue
c Override diagonal terms do 60 i-Onsurf
sum-OO do 70 j-Onsurf
sum-sum+F(ij) 70 continue
Amatrix(i+li+l)-(emmis(l-emmisraquo+sum 60 continue
c Call routine to solve the set of equations for unknown JS call gaussy(Amatrixbvectorradlnsurf+l)
do 80 i=Onsurf rad(i)=radl(i+l)
80 continue
return end
c----------------------------------------------------------------------shyc-----------------------------------------------------------------------
Subroutine Gaussy(abxn) c
integer nkiimaxjkplusllplus real a(nn)b(n)x(n)amaxbtempatemp
+ aeon sum
do 28 k=l n amax=OO do 4 i=kn if(abs(a(ikraquo-abs(amaxraquo442
2 amax=a(ik) imax=i
4 continue if(abs(amax)-0le-15)101014
10 printO equations are not independent return
14 btemp=b(k) b(k)=b(imax) b(imax)=btemp do 18 j=kn
atemp=a(k j) a(kj)=a(imaxj)
18 a(imaxj)=atemp kplus=k+l if(k-n)222828
22 do 24 i=kplusn b(i)=b(i)-b(k)a(ik)a(kk) acon=a(ik) do 24 j=kn
24 a(ij)=a(ij)-a(kj)acona(kk) 28 continue
132
l=n 32 sum=OO
if(1-n)343838 34 lplus-1+1
do 36 j-lplusn 36 sum=sum+a(lj)x(j) 38 continue
x(l)-(b(l)-sum)a(ll) if(1-1)424240
40 1-1-1 goto 32
42 return end
c----------------------------------------------------------------------shyc-----------------------------------------------------------------------
Subroutine sseqn(TriplusriminusrjplusrjminusAiplus + AiminusAjplusAjminusijNN)
c This subroutine computes the temperature at node (ij) c given the temperatures of the surrounding nodes and c the resistances leading to these nodes
integer ijNN real T(-1NN+10NN)riplusriminusrjplusrjminus real AiplusAiminusAjplusAjminus real c1c2c3c4c5
c1=Aiplusriplus c2=Aiminusriminus c3=Ajplusrjplus c4=Ajminusrjminus c5=1(c1+c2+c3+c4)
T(ij)=c5(c1T(i+1j)+c2T(i-1j)+c3T(ij+1)+c4T(ij-1raquo
return end
c----------------------------------------------------------------------shyc----------------------------------------------------------------------shy
real function f1(x) c door BC
real x f1-18520 - 23413x
return end
c----------------------------------------------------------------------shyc----------------------------------------------------------------------shy
real function f2(x) c wall BC
real x f2=18128 - 3475x
return end
c----------------------------------------------------------------------shyc----------------------------------------------------------------------shy
133
Fresh Food Compartment Simulations Results
Run 1 The prescribed temperature profiles are
Wall 19203 - 1908 x Door 19203 - 1206 x
(x is in meters)
Outdoor Ambient = 210 degC Local Indoor Ambient = 1533 degC
Run 2 The prescribed temperature profiles are
Wall 18989 - 2024 x Door 19078 - 1326 x
(x is in meters)
Outdoor Ambient = 210 degC Local Indoor Ambient = 1496 degC
Run 3 The prescribed temperature profiles are
Wall 1895 - 1998 x Door 19053 - 1384 x
(x is in meters)
Outdoor Ambient = 208 degC Local Indoor Ambient = 1491 degC
Ayem~ Values Wall 1905 - 1977 x Door 1913 - 1384 x
(x is in meters)
Ave Outdoor Ambient = 209 degC Ave Local Indoor Ambient =1507 degC
Loss from Fresh Food == 10 W
134
Freezer Compartment Simulations Results
Run 1 The prescribed temperature profiles are
Wall 1821 - 343 x Door 18606 - 2354 x
(x is in meters)
Outdoor Ambient = 210 degC Local Indoor Ambient = 1029 degC
Run 2 The prescribed temperature profiles are
Wall 18182 - 3542 x Door 18544 - 2398 x
(x is in meters)
Outdoor Ambient = 210 degC Local Indoor Ambient = 1042 degC
Run 3 The prescribed temperature profiles are
Wall 17993 - 3452 x Door 18411 - 2272 x
(x is in meters)
Outdoor Ambient = 208 degC Local Indoor Ambient = 1024 degC
Ayera~e Values Wall 18128 - 3475 x Door 18520 - 23413 x
(x is in meters)
Ave Outdoor Ambient = 209 degC Ave Local Indoor Ambient = 1032 degC
Loss from Fresh Food = 157 W
135
The Air Conditioning and Refrigeration Center was founded in 1988 with a grant from the estate of Richard W Kritzer the founder ofPeerless ofAmerica Inc A State of Illinois Technology Challenge Grant helped build the laboratory facilities The ACRC receives continuing support from the Richard W Kritzer Endowment and the National Science Foundation Thefollowing organizations have also become sponsors of the Center
Acustar Division of Chrysler Allied-Signal Inc Amana Refrigeration Inc Bergstrom Manufacturing Co Caterpillar Inc E I du Pont de Nemours amp Co Electric Power Research Institute Ford Motor Company General Electric Company Harrison Division of GM ICI Americas Inc Johnson Controls Inc Modine Manufacturing Co Peerless of America Inc Environmental Protection Agency U S Army CERL Whirlpool Corporation
For additional information
Air Conditioning amp Refrigeration Center Mechanical amp Industrial Engineering Dept University ofIllinois 1206 West Green Street Urbana IL 61801
2173333115
AN INVESTIGATION OF HOUSEHOLD REFRIGERATOR CABINET LOADS
Brian Edward Boughton MS
Department of Mechanical and Industrial Engineering University of Illinois at Urbana-Champaign 1992
ABSTRACT
This thesis presents an analysis of the cabinet loads of a typical household refrigerator
freezer The thennalload on the cabinet during closed door conditions is investigated The
area of greatest focus is the door and wall edge region of the refrigerator where thennal
losses are greatest Conduction heat transfer into the refrigerator cabinet is quantified using
numerical computer simulations and experimental measurements The overall cabinet load
is detennined as well as specific loads for various pathways that sum to equal the total
Based on agreement between simulations and experiments the complete edge loss accounts
for approximately 30 of the overall cabinet load on the fresh food and freezer
compartments In addition to this primary finding percentages for heat leakage directly
through the door gaskets along the steel casing at the wall and door flanges along the steel
skin in the mullion section due to the presence of a mullion anti-sweat heater and due to
the presence of an anti-sweat condenser tube are detennined
iii
T ABLE OF CONTENTS
Page
LIST OF TABLESvii
LIST OF FIGURES viii
1 INTRODUCTION 1
2 LITERATURE REVIEW5
3 ONE-DIMENSIONAL WALL AND DOOR LOADS 7
31 One-dimensional Heat Transfer ModeL 7 32 Determination of Effective Heat Transfer Coefficients 8 33 Results 10
4 EXPERIMENTAL ANAL YSIS 12
41 Temperature Profile Measurements 12 42 Thermopile Testing 14 43 Thermocouple Drag Testing 16 44 Experimental Determination of qwall and qdoor 19 45 Experimental Determination of qmulloff 21 46 Experimental Determination of qmullon 24 47 Determination of qmisc 27
5 NUMERICAL SIMULATION28
51 Wall Model 28 52 Wall Simulation to Determine qwall 32 53 Wall Edge Simulation to Determine qtube 36 54 Door Seal Simulation to Determine qseal 40
6 DISCUSSION OF RESULTS 46
61 Comparison of Simulation Results with Experimental Data 48 62 Mullion Analysis 49 63 Seal Analysis 49 64 Anti-sweat Condenser Tube Analysis 49 65 Overall Cabinet Load 50
7 SUMMARY OF CONCLUSIONS 54
REFERENCES 55
v
TABLE OF CONTENTS (CONTINUED)
Page APPENDIX A FUMED SILICA INVESTIGATION 56
Al Introduction56 A2 Thermal Properties 56 A3 Experimental Method 57 A4 Theory57 A5 Test Apparatus 59 A6 Results 61 A7 Conclusions 65 A8 Thermal Diffusivity Newton-Raphson Iteration Source Code 65
APPENDIX B ONE-DIMENSIONAL SIMULATION SOURCE CODE AND OUTPUT 69
Bl Source Code 69 B2 Output 71
APPENDIX C TEST REFRIGERATOR DESCRIPTION 73
APPENDIX D DATA ACQUISITION AND CONTROL SYSTEM 77
APPENDIX E EXPERIMENTAL DATA AND PLOTS 79
El Temperature Profile Plots From Fixed Thermocouples 79 E2 Thermopile Data Reduction 81 E3 Experimental Determination of qwall and qdoor Details 82 E4 Temperature Profile Plots From Mullion Data (Heater Off) 84 E5 Temperature Profile Plots From Mullion Data (Heater On) 87
APPENDIX F NUMERICAL SIMULATION EQUATIONS AND CODE 92
Fl Finite-Difference Equations 92 F2 Wall Simulation Source Code 94 F3 Fresh Food Wall Simulation Output 102 F4 Freezer Wall Simulation Output 108 F5 Fresh Food Wall Simulation Output Including
Anti-sweat Condenser Tube 115 F6 Freezer Wall Simulation Output Including
Anti-sweat Condenser Tube 120 F7 Seal Simulation Source Code and Output 125
vi
LIST OF TABLES
Page
31 One-dimensional Model Parameters 8 32 Results from One-dimensional Load Analysis 10
41 Thermopile Output 16 42 Experimental Determination of qwall and qdoor 20 43 Experimental Results from Mullion Analysis 24 44 Experimental Results from Heater Analysis 26 45 Miscellaneous Loads 27
51 Wall Simulation Input 30 52 Input Values 32 53 Wall Simulation Results 33 54 Wall With Condenser Tube Simulation Results 36 55 Seal Simulation Input 42 56 Seal Simulation Results 43
61 Comparison of Simulation and Experimental Values for qwall and qdoor 48 62 Overall Cabinet Loads 51
A1 Average Fumed Silica Conductivity for Various Bulk Densities 63 A2 Average Fumed Silica Diffusivity for Various Bulk Densities 64
E1 Thermopile Raw Data 82
F1 Model Resistors 92
V1l
LIST OF FIGURES
Page 11 Door Seal Region Cross Section 3 12 Mullion Region Cross Section 4
31 Model Used To Calculate One-dimensional Load 7
41 SteelSkin Temperature Profile Thermocouple Placement 12 42 Steel Skin Temperature Plot for Fresh Food Compartment 13 43 Steel Skin Temperature Plot for Freezer 14 44 Thermopile Test Apparatus 15 45 Thermopile Placement ~ 16 46 Thermocouple Drag Test Apparatus 17 47 Drag Profiles (Fresh Food) 18 48 Drag Profiles (Freezer) 19 49 Heat Flow Paths in Mullion 21 410 Mullion Face Plate Cross Section 22 411 Mullion Temperature Profile 23 412 Electric Heater Location 25 413 Mullion Temperature Profile With Heater On (Center) 26
51 Wall Heat Conduction Model Sketch 29 52 Non-adiabatic Door Seal 31 53 Fresh Food Wall Temperature Distribution 34 54 Freezer Wall Temperature Distribution 35 55 Tube Location for Simulation 36 56 Fresh Food Wall Temperature Distribution
Including Warm Anti-sweat Tube 37 57 Freezer Wall Temperature Distribution
Including Warm Anti-sweat Tube 38 58 Load Due to Condenser Tube for Various Tube Placements 39 59 ~ercentage of Heat Entering Cabinet for Various Tube Placements 39 510 Seal Simulation Mesh Layout 40 511 Seal Cavity Mesh Details 41 512 Seal Temperature Distribution (Fresh Food) 44 513 Seal Temperature Distribution (Freezer) 45
61 Refrigerator System Load Graph 46 62 Cabinet Loads Graph 47
A1 Fumed Silica Test Apparatus 59 A2 Fumed Silica Test Facility Schematic 60 A3 Time vs Temperature for Unpacked Run 61 A4 Natural Log Time vs Temperature for Unpacked Run 62 A5 Conductivity vs Bulk Density 63 A5 Diffusivity vs Bulk Density 64
viii
LIST OF FIGURES (CONTINUED)
Page
C1 Location of Anti-sweat Devices and Overall Dimensions of Test Refrigerator 73
C2 Fresh Food Compartment Interior Dimensions 74 C3 Fresh Food Door75 C4 Freezer Interior Dimensions 76 C5 Freezer Door76
D1 Data Acquisition and Control System 78
E1 Steel Skin Temperature Plot for Fresh Food Compartment (Run 2) 79 E2 Steel Skin Temperature Plot for Fresh Food Compartment (Run 3) 80 E3 Steel Skin Temperature Plot for Freezer (Run 2) 80 E4 Steel Skin Temperature Plot for Freezer (Run 3) 81 E5 Mullion Temperature Profile Run 2 (Heater Off) 84 E6 Mullion Temperature Profile Run 3 (Heater Off) 85 E7 Mullion Temperature Profile Run 4 (Heater Off) 85 E8 Mullion Temperature Profile Run 5 (Heater Off) 86 E9 Mullion Temperature Profile Run 2 (CenterHeater On) 87 E10 Mullion Temperature Profile Run 3 (CenterHeater On) 88 E11 Mullion Temperature Profile Run 1 (LeftHeater On) 88 E12 Mullion Temperature Profile Run 2 (LeftHeater On) 89 E13 Mullion Temperature Profile Run 3 (LeftHeater On) 89 E14 Mullion Temperature Profile Run 1 (RightHeater On) 90 E15 Mullion Temperature Profile Run 2 (RightHeater On) 90 E16 Mullion Temperature Profile Run 3 (RightHeater On) 91
F1 Generic Nodal Resistor Network 92
IX
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1 INTRODUCTION
New regulations recently announced by the Department ofEnergy call for substantial
energy efficiency increases for household appliances by 1993 The refrigerator is of
particular interest since it is the largest household consumer of electricity and accounts for a
large part of the 8 of the electricity used in the US for food-cooling both residential and
commercial In addition to efficiency standards regulations are being imposed on the use
of CFCs completely banning their use by the year 2000 (Braswell 1988)
The objective of this thesis is to present an analysis of all heat transfer paths from the
surroundings to the interior food compartments of the refrigerator under closed door
conditions Both experimental and numerical methods are used as a means to determine the
overall cabinet load as well as the load due to each pathway The study is focused on a
particular unit for practical purposes However the methods implemented may be applied
to any make or model to aid in the search for high efficiency cabinets
All loads determined in this study are strictly cabinet loads and not the loads seen by the
refrigerator system The thermal load on the cabinet is comprised of three main parts (i)
the load due to the one-dimensional heat transfer through the walls and doors to the food
compartments away froin the edges (ii) the load due to edge effects that is heat transfer
into the food storage compartments via paths around the perimeter of the cabinet aperture
and (iii) other miscellaneous sources
(11)
The determination of qlD is straightforward and is discussed in detail in Chapter 3 The
edge load must be broken down into several parts for examination
qedge = qwall + qdoor + qseal + qrnullon + qtubeave (12)
where
qwall heat input due to conduction along the wall steel flange
qdoo heat input due to conduction along the door steel flange
qseal heat conduction directly through the door seal
1
heat input due to conduction in the mullion region with the additional input from an anti-sweat heater
qtubeave heat input due to cabinet anti-sweat condenser tube averaged over the cycle time
heat input due to cabinet anti-sweat condenser tube
heat input due to conduction in the mullion region electric heater off
It is assumed that an electric anti-sweat heater in the mullion region is in use for the entire
cycle The test unit chosen for this study required this region to be heated almost
continually to eliminate condensation This load is represented by qmulloo in Eq (12)
The load qmulloff is due to heat conduction to the interior compartments at the mullion
region when the electric heater is off Although this value does not appear in the edge load
definition it is still important to detennine for sake of comparison with the value of
qmulloo The load due to the presence of an anti-sweat condenser loop around the aperture
of the cabinet is defmed as qtube Since this load is present for the on cycle only it must be
integrated over the cycle time to be included in Eq (12) hence the tenn qtubeave
The tenn qroisc is expressed as
qmisc = qfanave + qdefrostave + qcompave (13)
where
qfanave heat input from the evaporator fan averaged over the cycle time
qdefrostave heat input from the defrost heaters averaged over defrost cycle time
qcompave heat input from elevated exterior walls near the running compressor
Figure 11 is a cross sectional drawing of the door seal area of the test refrigerator
examined to detennine qwalI qdoor and~ The figure includes materials and their
properties taken from Incropera and Dewitt (1985)
2
400 ~I-I~ 065~
065 Only dimension that is different for the freezer
200
kltWIm-K)
Outer Steel Skin 540 312~ Polyurethane Wall Insulation 0027 0015- Inner Plastic Skin 015 009~
~ Rubber Gasket 03 017fm1I ~ ~ Glass Fiber Door Insulation 004 0023
All dimensions in millimeters
1 in= 254mm
Fig 11 Door Seal Region Cross Section
3
Figure 12 is a drawing of the mullion region cross section of the test refrigerator examined
to detennine ltlmullon and ltlmulloff
FREEZER
Freezer Gasket
Fresh Food Gasket
FRESH FOOD COMPARTMENT
Fig 12 Mullion Region Cross Section
The remainder of this thesis is devoted to the analysis of the closed door cabinet loads and
the experimental and numerical techniques used for their detennination
An experimental investigation of fumed silica as an alternative insulation for the refrigerator
is presented in Appendix A Although this appears to be a departure from the main topic
a relation exists The desire of higher efficiency requires a search for equal if not better
cabinet insulations that do not incorporate the use of ozone damaging CFCs Testing is
done to detennine the thennal conductivity and diffusivity of fumed silica for several
densities
4
2 LITERATURE REVIEW
The new energy standards imposed by the Department ofEnergy have sparked research in
the area of refrigerator efficiency and alternative refrigerants A study by Turiel and
Heydari (1988) focused on several ways to improve the efficiency of refrigerator-freezers
and freezers
Various classes for the study were chosen however the paper presents extensive results for
the most common variety a top-mounted automatic defrost refrigeratorfreezer The
design options considered were those changes that can be incorporated into the existing
refrigerator design Two types of improvements are noted (i) changes that increase energy
efficiency by decreasing the heat transfer into the cabinet and (ii) changes that increase the
efficiency by reducing auxiliary electricity use or improving the refrigeration system Type
(i) changes include Foam insulation substitution increased insulation thickness double
door gaskets improved foam insulation evacuated insulation panels and reduced heat load
of through-the-door feature Type (ii) changes include High efficiency compressor
substitution adaptive defrost fan and fan motor improvement anti-sweat heater switch
increased evaporator surface area hybrid evaporator enhanced heat transfer surfaces
mixed refrigerants improved expansion valve fluid control valve two-compressor system
use of natural convective currents and location of compressor condenser and evaporator
fan motor
Turiel and Heydari used a model developed by Little (1982) to carry out the energy use
simulations This model is a steady-state energy use simulation which computes the heat
leakage to the cabinet and then determines the energy needed to maintain the interior
ambient temperatures dictated by the OOE test procedure Turiel and Heydari present the
energy consumption figures for a 18 cubic foot top-mounted automatic defrost
refrigeratorfreezer as a baseline case They find that 74 of the total energy is accounted
for by the compressor 11 is for the anti-sweat heaters 10 is for the fans and 5 is
for the defrost heaters for a total of 947 kWhyr Also about 10 of the compressor
energy use is for the removal of internal heat generated by the evaporator fan motor defrost
heater and anti-sweat heaters
Several subsequent simulations were performed each time adding a design option that was
projected to improve efficiency The improvement levels were added cumulatively and
results were given on compressor run time heat leakage rate into the cabinet compressor
5
power demand at the operating point fan motor operating power for the evaporator and
condenser fans anti-sweat heater power and total daily and annual energy consumption
The goal here was to achieve by the last level of improvement the minimum energy
consumption that is technologically feasible One important fmding for all product classes
tested the highest efficiency was obtained by the use of evacuated panels in the planar
walls For example for the top-mounted automatic defrost unit the minimum energy use
was 515 kWyr
Finally an energy usevolume relation was developed from a linear regression obtained
from simulation results The resulting fit was shown as
Energy Use = Cl + C2Adjusted Volume
The constant Cl indicates the direct energy use to remove the cabinet loads associated with
the fan motors and heaters The slope C2 is an indicator of the rate of change ofenergy use
with a change in the adjusted volume This value reflects the rate of cabinet heat gain The
adjusted volume is the volume of the fresh food compartment plus 163 times the volume
of the freezer Turiel and Heydari produced a series of regressions for all of the defined
levels of design improvements allowing easy comparison at a specific adjusted volume
6
3 ONE-DIMENSIONAL WALL AND DOOR LOADS
In this section the overall steady cabinet load is calculated without considering the addition
of edge loading This load qlD is dermed as the heat transfer from the exterior
environment to the interior of the refrigerator under nonnal closed-door operating
conditions through four primary conductive paths (i) fresh food compartment walls (ii)
freezer walls (iii) fresh food door and (iv) freezer door In a later chapter the load due to
edge loading will be examined more closely
31 One-dimensional Heat Transfer Model
The steady conductive heat transfer through the walls of the refrigerator cabinet is
computed using a simple computer program written by Qausing (1983) This program
estimates inside and outside effective heat transfer coefficients using a flat plate natural
convection correlation Using these coefficients and the material properties and dimensions
of the wall insulation the one-dimensional heat transfer through the cabinet walls is
approximated for the fresh food and freezer compartments Figure 31 shows the
resistances and boundary conditions use in the model
Fig 31 Model Used To Calculate One-dimensional Load
7
The model provides flexibility for varying several parameters This allows application to
various types of refrigerator walls and doors Table 31 lists the input and output
parameters for the model The source code of the simulation along with the output for
completed runs are included in Appendix B
Table 31 One-dimensional Model Parameters
Input Parameters
To K (F) Room ambient temperature
Ti K (F) Interior ambient temperature
LiDs m (ft) WalVdoor insUlation thickness
kiDs Wm-K (Btuhr-ft-F) WalVdoor insulation thermal conductivity
A m2 (ft2) Cabinet surface area
Output
beo Wm2K (Btuhr-ft2_F) Exterior convective heat transfer coefficient
bei Wm2K (Btuhr-ft2-F) Interior convective heat transfer coefficient
hro Wm2K (Btuhr-ft2_F) Exterior effective radiative heat transfer coefficient
hri Wm2-K (Btuhr-ft2_F) Interior effective radiative heat transfer coefficient
qlD W (Btuhr) Heat transfer rate through specified section
32 Determination of Effective Heat Transfer Coefficients
The simulation developed automatically estimates the inside and outside effective heat
transfer coefficients This effective value is the sum of the convective and radiative
components which are defined below
The radiative heat transfer coefficients are computed iteratively using eqs (31) and (32)
assuming (i) gray walls at temperatures T wi or Two with emissivities poundi and Eo (ii) black
surroundings at Ti or To and (iii) walls can see surroundings only
(31)
(32)
8
The convective heat transfer coefficients are estimated from a flat plate natural convection
correlation developed by Clausing (1983) In the laminar regime (Ra lt 1()9) the Nusselt
number based on the film temperature is given by Eq (33)
NUf = 052 Ra4 (33)
For the turbulent regime (Ra ~ 109) the Nusselt number becomes
NUf = 009 Raf3 (34)
where in both cases
Tw+T_ Film temperature T f == 2
Lc == Vertical surface characteristic length g == Gravitational acceleration f3 == Thermal expansion coefficient v == Kinematic viscosity Tw == Vertical wall surface temperature T_ == Outsideinside ambient temperature
kf == Air thermal conductivity
The film temperature characteristic length Nusselt number and Rayleigh number will
have different values for the inside surface compared with the outside surface of the
cabinet Therefore the inside and outside convective heat transfer coefficients are
determined separately from eqs (35) and (36)
(35)
- NUfo kfohco - (36)Leo
9
33 Results
The four primary regions analyzed are (i) the fresh food compartment walls (ii) fresh food
door (iii) freezer walls and (iv) the freezer door The values for the input parameters
ltLins kins A) are taken from a full-size unit that is used for the experimental analysis
presented in Chapter 4 The room temperature is used for the model parameter To Also
the fresh food ambient Tee and the freezer ambient Tfz are substituted for Ti when
suitable in order to closely simulate real operating conditions The results are given in
Table 32
Table 32 Results From One-dimensional Load Analysis
Input
Section TooC eF)
Tj degC eF)
Lins m (ft)
kins Wm-K (Btuhr-ft-OF)
A m2 (fi2)
Fresh Food 21 4 0045 0027 242 Walls (698) (392) (0148) (0015) (2605)
Fresh Food 21 4 0040 0040 089 Door (698) (392) (0131) (0023) (958)
Freezer 21 -10 0056 0027 110 Walls (698) (-140) (0184) (0015) (1184)
Freezer 21 -10 0040 0040 034 Door (698) (-140) (0131) (0023) (366)
Output
Section hco Wm2-K cBtuhr-ft2-Fl
hro Wm2-K iJtuhr -ft2-Fgt
hci Wm2-K (Btuhr-ft2-F)
hri Wm2-K 1Btuhr-ft2-F)
qlD W (Btuhr)
Fresh Food 130 544 198 461 209 Walls (23) (96) (35) (81) (713)
Fresh Food 144 542 218 463 117 Door (25) (95) (38) (82) (399)
Freezer 143 542 226 397 143 Walls (25) (95) (39) (70) (488)
Freezer 164 538 259 400 81 Door (29) (94) (46) (70) (276)
herro =687 Wm2 K (121 Btulhr-ft2-OF) Total qlD =550 W herrrr = 670 Wm2 K (118 Btulhr-ft2_0F) (1876 Btuhr)
herrrz = 641 Wm2 K (113 Btulhr-ft2-OF)
The load for our operating conditions is 550 W (1876 Btuhr) Once again this quantity
does not reflect the total cabinet load on the refrigerator cabinet Edge effects are analyzed
in detail in the following chapters Another important result is the values for the effective
10
inside and outside heat transfer coefficients which are simply the sum of the convective
and radiative components The outside coefficient is heffo the fresh food coefficient is
heffff and the freezer coefficient is hefffz These numbers are used whenever film
coefficients are needed for computations
11
4 EXPERIMENT AL ANALYSIS
This section presents an experimental study performed on a full-size household
refrigerator In Chapter 3 we defined the load due to heat transfer through the walls and
doors of the cabinet as qlD The purpose of this experimental analysis is to quantify qwalh
qdoor qmulloff and Qrnullon and Qmisc Three types of tests are performed to accomplish
this task Descriptions of each are presented separately in the sections that follow
41 Temperature Profile Measurements
The refrigerator is instrumented with many thermocouples in various key areas to give
temperatures across the steel skin and to compare and verify the thermopile tests outlined
in the next section The four primary paths along the steel flange that are examined are the
wall-side fresh food door-side fresh food wall-side freezer and the door-side freezer
Five Type T 36 AWG thermocouples are placed along the skin for each path Figure 41
is a detailed drawing of the location of the thermocouples
Wall side TICs Door side TICs with 5 mm spacing with 5 mm spacing
Fig 41 Steel Skin Temperature Profile Thermocouple Placement
The wire leads are oriented so they run perpendicular to the temperature gradient so as to
reduce any effects of conduction along the wire to the bead The temperature data are fed to
the data acquisition system Each channel is a thermocouple input and is scanned at a rate
of 5 times a second The data are smoothed automatically by the software in blocks of 10
12
points for an average temperature every 2 seconds A full description of the data
acquisition and control system is provided in Appendix D
Data are collected for several runs to provide a good base to detennine average values since
the test conditions vary slightly from run to run To get a good measurement of the
temperature profIles along the steel flange the unit is shut off at the beginning of the run
and allowed to drift to quasi-steady conditions The presence of a large amount of thennal
mass (see Appendix C) within the refrigerator provides for a stable interior ambient
temperature during data collection The outer ambient is controlled by the room thennostat
which keeps the laboratory at a constant temperature to within plusmn1degC
Figure 42 is an example plot of a run that gives the temperature profIles along the steel
skin on the wall-side and door-side for the fresh food compartment
193
192
G 191 ~
i 19
middot5 189F
188
Run I iii --0 - Door Profile
~Imiddotmiddotmiddotmiddotmiddotmiddotmiddott 0 Wall Profue
i ~ i - - T =19273 - 001206x i i-- door i If ~
=-r~r==L~r=I ~ I +~~=~~~~~~~~~ middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot
Outdoor Ambient = 210 degC Fresh Food Ambient =48 degC
187-+----+----J------I----+---~
o 5 10 15 20 25
x (mm) 1 in= 254 mm
Fig 42 Steel Skin Temperature Plot for Fresh Food Compartment
The dashed line represents a linear least-squares fit for the door data and the solid line is the
corresponding fit for the cabinet wall data Each data point in the plot represents the
average temperature at that point over a period of time at quasi-steady conditions
Similarly Figure 43 is a plot of the temperature profIles for the freezer
13
186
184
a 182
~
i 18
5 178~
176
174
Run 1 t-- 1 1 --0 - Door Profde
P~P1 0 Wall Profile
- -LLl--=-+--shy- - Tdo = 18606 - O02354x i
or ~
=c==-rc1 1 ltb 1 ~
~~r--r- -r---shy0 5 10 15 20 25
x (mm) 1 in= 2S4mm
Fig 43 Steel Skin Temperature Plot for Freezer
A total of six separate runs were perfonned three for the fresh food compartment and three
for the freezer Plots for the other runs are located in Appendix E
From the figures above for the fresh food compartment the slope on the wall-side is
slightly steeper than the slope on the door-side In fact this trend is seen for all the runs
Therefore the heat conduction along the metal skin into the cabinet along the wall is
somewhat greater than that of the door For the freezer the slopes are nearly equal hence
the heat conduction along the wall skin and the door skin are nearly the same
42 Thermopile Testing
Another simple but important test is the use of a thennopile to measure the average
temperature difference at various locations on the steel flange regions of the unit Figure
44 is a schematic of the thennopile test set-up The thennopile is constructed from 36
AWG copperconstantan thennocouple wire
14
-
CopperConstan$t Junctions 285 mPt
IOmm
10mmThermopile
IOmm
Digital Multimeter
1 in= 254mm
Fig 44 Thermopile Test Apparatus
Five junctions are used for the fresh food compartment and three for the freezer The
junctions are mounted 10 mm (039 in) apart from one another along the steel skin beneath
the door seal Figure 45 is a detailed drawing of the lateral location of the thermopile
junctions
15
1 in =254 mm
Fig 45 Thermopile Placement
The thennopile provides an average temperature difference across the junctions The
output voltage must frrst be divided by the number of pairs of junctions and then translated
into a temperature difference using a referencing chart for the thennocouple wire Table
41 is a summary of the results from these tests The output voltages are read accurately to
within plusmn0002 mV The raw data and data reduction procedure are given in Appendix E
Table 41 Thermopile Output
Test Conditions Fresh Food aT Freezer aT TodegC
(OF) TffoC
(OF) Tfzoc
(OF) aTwallff degC
(Of) aTdoorffoc
(OFgt aTwallfzoC
(Of) aTdoorfzoC
(OFgt
1 210 (698)
48 (406)
-88 (162)
026 (047)
024 (043)
037 (067)
041 (074)
2 210 (698)
37 (387)
-87 (163)
027 (049)
026 (047)
038 (068)
040 (072)
3 208 (694)
37 (387)
-93 (153)
027 (049)
026 (047)
038 (068)
040 ( 072)
Average Values 209 (696)
40 (392)
-90 (158)
0267 (0481)
0253 (0455)
0377 (0679)
0403 (0725)
43 Thermocouple Drag Testing
One final technique applied is thennocouple drag testing This is a more qualitative method
to supply insight into what exactly is happening when the compressor is pumping wann
16
refrigerant through the anti-sweat tube that lines the perimeter of the cabinet aperture The
main objective of this test is not to give accurate temperature proftle infonnation but
instead to detennine the placement of the condenser tube This is needed as an input for
the numerical simulation of this region The reason that the temperature are not accurate is
the fact that the thermocouple is being dragged across a surface where good thermal contact
may not occur and significant energy may be generated Figure 46 is a schematic of the
apparatus used for drag testing
Power Supply
Data Acquisition System
Outer Metal Skin
Potentiometer
Inner Plastic Skin
Condenser Tube
Fig 46 Thermocouple Drag Test Apparatus
This device is quite simple yet very effective The type T 36 AWG thennocouple begins
at the interior boundary of the steel skin beneath the seal on the wall-side of the cabinet
The potentiometer is turned by hand moving the thennocouple oqtward along the skin
The temperature and location are stored simultaneously this way The thennocouple is kept
17
pressed against the steel flange by the seal The linear translation of the thennocouple is a
function of the output voltage Voutbull
s = 2mllT Vout (41)Yin
r =radius of potentiometer post =30 mm (012 in)
nT = total number of turns of potentiometer = 10
Vin = input voltage = 05 V
Vout = output voltage
Drag tests are run on the wall steel skin for both the fresh food compartment and the
freezer Runs are perfonned at four separate times the first being when the compressor
turns on Figure 47 is a plot of the drag proflles across the wall-side skin in the fresh food
compartment Figure 48 is a plot of the profiles in the freezer compartment The same
trends are generally seen for both regions The freezer profiles are simply shifted down in
temperature values as expected The temperature peak seems to move through time to
settle near the center of the flange region under the seal
31
30
29
G
i 28~
27
26~
25
24
23
e
Ji ~ i i i 1middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotlmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddoti~~
---l- Time 4
o Time 2 rr
i
0 5 10 15 20 x (mm)
Fig 47 Drag Profiles (Fresh Food)
18
26~--------+---------~-------4--------~
i ~
Time 1 24
22
20
18
16~~------+---------~-------4--------~
4 __
~~Time3
middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot_middotmiddot_middotmiddotimiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot
Outer Seal Edge o
o 5 10 15 20
x (mm)
Fig 48 Drag Profiles (Freezer)
44 Experimental Determination of qwall and qdoor
The results from the temperature profile and thennopile testing are used to detennine qwall
and qdoor according to the following defmitions
qwall = qwallff + qwallfz (42)
(43)
Where qwal1ff = heat conduction along wall-side fresh food compartment steel flange
qwallfz = heat conduction along wall-side freezer compartment steel flange
qdoorff = heat conduction along door-side fresh food compartment steel flange
qdoorfz = heat conduction along door-side freezer compartment steel flange
The trends derived from the fixed profiles exhibit generally good agreement with the
temperature differences seen by the thennopile For the fresh food compartment the
thennopile displays a slightly larger AT than what is seen in the profiles and both give a
19
slightly larger temperature difference for the wall-side compared with the door-side For
the freezer the temperature differences match closely on the wall-side however the doorshy
side AT is shown to be somewhat less than the wall-side AT for the fIXed thennocouple
measurements where the opposite is seen from the thennopile The worst discrepancy is
on the order of 10 and is probably due to the fact that the thennopile gives an average temperature difference at several vertical locations on the wall whereas the other method is
at one vertical location only
Since the thennopile produces an average temperature difference across the steel skin its
output is used to detennine the heat flux into the cabinet The refrigerator casing is being
used as a heat meter Thus the flux along the skin in the fresh food compartment on the
wall-side is
kmiddot ATwallffqwallff = m (44)
Ax
The load qwallJf is Eq (44) multiplied by the cross sectional area This area is the
thickness of the steel casing multiplied by the perimeter that is exposed to the room
ambient This perimeter varies for each of the two paths that comprise qwall and the two
paths that comprise qdoor The other cabinet loads are computed in a similar way and are
given in Table 42 The details of these values are given in Appendix E
Table 42 Experimental Determination of qwall and qdoor
Section Load W (BtuIhr)
qwallJf 28 (96)
qwallJz 21 (72)
qwall 49 (168)
qdoorff 33 (112)
qdoorJz 33
1112)
qdoor 66 (224)
20
45 Experimental Determination of qmulloff
The region that lies between the fresh food compartment and the freezer is called the
mullion The front portion of the mullion is covered by a thin steel face plate to provide a
suitable interface for the door seal magnets In this section the load due to heat conduction
along the mullion steel skin into the freezer and fresh food compartment is detennined
based on the experimental data
The heat transfer rate qmulloff is sum of two parts The first component is the heat
conduction along the steel plate into the fresh food compartment and the second is the
conduction into the freezer
qmulloff = qmulloffff + qmullofffz (45)
Figure 49 schematically illustrates paths of these two components
FREEZER
FRESH FOOD COMPARTMENT
Fig 49 Heat Flow Paths in Mullion
21
Ten 36 A WG type T thennocouples are mounted from top to bottom across the steel face
plate Figure 410 shows the cross section of the plate and the location and numbering of
the thennocouples
FREEZER
1bennocouplesSteel Face (5 mm spacing from
Plate bottom edge)
Freezer Gasket
Fresh Food Gasket
10 50
FRESH FOOD COMPARTMENT
1 in =254 mm
Fig 410 Mullion Face Plate Cross Section
Data are gathered from the ten thennocouples when the unit is shut off and allowed to drift
to a quasi-steady ambient temperature A total of five runs were perfonned Figure 411 is
a sample plot of the quasi-steady temperature profile All other plots are contained in
AppendixE
22
116
Run 1 I 115 ICcIIIII114 iii t ~mull~ =12~7 - 00~654xa
~ 113
rrfIIJ~~If112i 5 )mullfz 1= 1081~ + OOdl25X 111111 ~
11 oo+-t--t-iH-+-lo-shyiii i i Room Ambient = 2184 degc
109 middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1middot Fresh Ambient = 381 OC
108
1 10
I I I I I Freezer Ambient =-832 degc
2 3 4 5 6 7 8 9
TIC
Fig 411 Mullion Temperature Profile
The plot also shows two linear equations These represent linear fits to each side of the
peak temperature at TIC 7 The slopes (shown in degCmm) are used to detennine the heat
conduction to each compartment by eqs (46) and (47)
lmulloffff = km A (aT) (46)ax offff
qmul)offfz = km AIll) (47)ax offfz
The cross sectional area is the product of the face plate thickness (10 mm 0039 in) and
the length of the mullion (717 mm 2825 in) The average slopes from all five runs are
used to detennine qmulloffff and qroullofffz The results are given in Table 43
23
Table 43 Experimental Results from Mullion Analysis
Load W (Btuhr)
09qmullofUz (31)
07qmulloffff (24)
16qmuIlorr (55)
46 Experimental Determination of qmullon
In this section the load due to heat conduction along the mullion steel skin into the freezer
and fresh food compartment when an anti-sweat heater is on is experimentally determined
The test unit is equipped with an electric anti-sweat heater to eliminate condensation in the
mullion region The heater is installed on the back side of the plate and may be switched on
manually when needed It is a wire resistor type rated at 10 watts
The heat transfer rate qmullon is composed of two parts The first component is the heat
conduction along the steel plate into the fresh food compartment and the second is the
conduction into the freezer similar to ~ul1off
qmuIlon = ~ullonff + qmuIlonfz (48)
The location of the wire heater and the heat transfer paths are shown in Figure 412
24
FREEZER
qmullonfz
qmullonff
FRESH FOOD COMPARTMENT
Fig 412 Electric Heater Location
A series of tests are perfonned while the heater is on and the refrigerator is cycling
nonnally Three runs are done at each of three separate locations along the mullion
laterally (i) LEFT dermed as 180 mm (71 in) from the left-hand side of the unit (ii)
RIGHT 180 mm (71 in) from the right-hand side of the unit (iii) CENTER at center of
the mullion Figure 413 is a plot of the temperature profile across the face plate when the
heater is on for a specific test run The plots for all other runs are provided in Appendix E
The plot shows two profiles These represent the upper and lower limits as the unit cycles
The upper limit occurs just before the compressor turns on while the lower limit is at the
point in time just before the compressor shuts off At all times in between the profile
oscillates between the two limits maintaining nearly the same shape Once again a linear
fit is applied to the data on the fresh food side and the freezer side
25
30 iii imiddot iii i
29
28
27
Run 1
T mu
ill~~ 11 f = 26707 + 010776x Tmu11ff = 3128 - 00793x
Z +_ a 26~
I ~
middotmiddotmiddotbull-middotbullimiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotimiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotimiddotmiddotmiddotimiddotmiddot
24
25
e 23~ =H-T+H~i=i=
iimiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotimiddotmiddot T 11 ff = 27435 - 009504x 22 Tmullfz =21865 + 01l786x I m~ iii
21 -lmiddotmiddotmiddotmiddotmiddotmiddotmiddot-tmiddot Upper Limlt 0
20 middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotjmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotimiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddott 0 Lower Limit
19
0 1 2 3 4 5 6 7 8 9 10
TIC I
Fig 413 Mullion Temperature Profile With Heater On (Center)
Heat fluxes are computed identically to the method in Section 45 using the average slopes
from all nine runs The minimum value occurs just before to compressor turns on while
the maximum value occurs just before the compressor shuts off during normal cycling
The load is averaged over the cycle time which is approximately 50 for the test unit and
laboratory conditions The results are given in Table 44
Table 44 Experimental Results from Heater Analysis
Lower Profile Average W
(BtuIhr)
Upper Profile Average W
ffituhr)
qmullonfz 73
(249) 53
(181)
qmullonff 23 (78)
26 (89)
96 (32 7)
79 (270)
qmullon 88
300)
26
47 Determination of Qmisc
The load qoisc is comprised of three main parts The first is the load due to the evaporator
fan motor The fan that moves cool air in the cabinet also adds a thennalload Fans of this
type in use range from 8 - 16 watts The fan of our test unit is rated at 92 watts This
value must be integrated over the cycle time The cycle time for the unit is approximately
50 for the test conditions Thus the value of qfanave is 46 watts
The load qdefrostave is not determined experimentally Instead an estimate is obtained from
a similar study done by Turiel and Heydari (1988) This value is 5 watts which is an
average of the defrost heater input over the defrost cycle The defrost cycle can range from
10 - 12 hours of compressor run-time
The fmalload qcompave is detennined by measuring the cabinet surface temperature at the
region surrounding the compressor and computing the heat transfer locally The value is
found to be 2 watts Table 45 summarizes the results
Table 45 Miscellaneous Loads
Load W CBtuhr)
46 qfanave (15middotU
50 qdefrostave _07Ql
20 qcompave (68)
116 Qmisc (395)
27
s NUMERICAL SIMULATION
In this chapter a two-dimensional numerical model which is used to simulate the steadyshy
state heat transfer in the wall near the door seal is discussed The results from the model
include a computation of qwallff qwallfz and the complete temperature distribution across
the section The model is also used to estimate the additional cabinet load due to the
presence of an anti-sweat condenser tube embedded beneath the outer casing that runs
along the perimeter of the unit A separate model is presented which is used to simulate the
two-dimensional heat transfer across the door seal cross section The results are used to
determine qseal
51 Wall Model
A finite-difference technique is used to approximate the steady-state temperature
distribution in the wall section The technique is applied to solve the governing steady
two-dimensional heat conduction equation (assuming constant conductivity with no
generation)
(51)
Equation (52) is the basic fmite-difference representation of the conduction equation in a
homogeneous medium of constant conductivity with no heat generation (White 1988) In
Appendix F a complete list of all the model difference equations is provided
2(1+(3)Tij = (3Tij+l + Ti+lj+(3Tij-l + (3Ti-lj (52)
where (3 = (llxlly)2
28
Figure 51 is a sketch of the model representation of the refrigerator wall at the door seal region The dimensions shown are flexible parameters in the model The model allows for
slight changes in the geometry as well as changes in mesh size in both x and y directions
However the mesh size must remain uniform across the section
s5 s6
sl
Fig 51 Wall Heat Conduction Model Sketch
For each of N unknown nodal temperatures N simultaneous linear algebraic equations are obtained for N unknowns If N is large as is the case for this simulation an iterative
technique is preferred to solve the system ofequations A Fortran program has been
written to carry out the finite-difference iteration A copy of the code is given in Appendix
F A simple Guass-Seidel technique is employed for the differencing iteration At each
iteration an energy balance is done for the entire section In theory this balance should be
29
zero (heat entering) = (heat leaving) The iteration is continued until the difference
between heat entering and heat leaving is equal to 1 of the total heat entering the section
Table 51 defines the input parameters for the simulation
Table 51 Wall Simulation Input
Code Parameter Definition
To C (F) Exterior surrounding ambient temperature
Ti C (F) Interior ambient temperature
lan Wm-K (Btuhr-ft-F) Steel skin conductivity
kp Wm-K (Btuhr-ft-F) Plastic skin conductivity
kins Wm-K (Btuhr-ft-F) Wall insulation conductivity
heffo Wm2-K (Btuhr-ft2-F) Outside effective heat transfer coefficient
hefti Wm2-K (Btuhr-ft2-F) Inside effective heat transfer coefficient
dm mm (in) Steel skin thickness
dp mm (in) Plastic skin thickness
dx mm (in) Mesh size x direction
dy mm (in) Meshsizeydirection
sl mm (in) Wall width
s2 mm (in) Wall length
b mm (in) Effective Perimeter
s3 mm (in) Seal indentation
s4 mm (in) Seal width
s5 mm (in) Depth of steel skin into cabinet along seal boundary
s6 mm (in) Width of plastic skin along seal boundary
The model assumes that the boundary that lies along the door seal is adiabatic This allows
the separation of the wall section from the rest of the geometry in this region The seal and
door can then be treated separately later A simple calculation is done to validate this
assumption
30
Steel Skin (Refrigerator wall)
Seal (k = 02 Wm-K)
Fig 52 Non-adiabatic Door Seal
A 2 degC temperature difference AT is imposed across the seal This is a slight overshy
estimate based on the experimental data An estimate of the conductive heat flux is
determined from Eq (53)
ATqerror=k- (53) Ax
qrror =02 Wm-C o~Cm =20 Wm2
The heat flux ql for the fresh food compartment is determined in Appendix E to be 14418
Wm2 Therefore qerror represents approximately 13 of the total flux Hence this
term is neglected in this study
Two other possible sources of error are associated with the fmite-difference technique itself
(Ozisik 1980) The fIrSt is called truncation error and arises from the discretization of the
second-order derivative in the steady conduction equation The second is referred to as the
round-offerror which is due to the fact that numerical calculations are carried out only to a
finite number of decimal places Repeated solution with smaller increments shows that the
truncation error is negligible The precision of the energy balance is evidence that the
round-off errors are negligible
31
S2 Wall Simulation to Determine qwall
The finite-difference model is used to detennine the wall-side heat transfer along the steel
skin However more valuable information is yielded from the simulation The nodal
temperature distribution is detennined which gives insight into the direction and magnitude
of heat fluxes throughout the section The fresh food compartment and the freezer are both
simulated to detennine qwallff and qwallJz respectively Table 52 is the list of the values
used for the model input parameters for both cases
Table S2
Code Parameter
To C eF)
Ti C eF)
kIn Wm-K (Btuhr-ft-F)
kp Wm-K (Btuhr-ft-F)
kins Wm-K (Btulhr-ft-F)
heffo Wm2-K (Btuhr-ft2_F)
heffi Wm2-K (Btuhr-ft2-F)
dm mm (in)
dp mm (in)
dx mm (in)
dy mm (in)
sl mm (in)
s2 mm (in)
b mm (in)
s3 mm (in)
s4 mm (in)
s5 mm (in)
s6 mm (in)
Input Values
Fresh Food 210 (698) 40
(392) 540 (312) 015 (009) 0027 0015t 687 (121) 670 (118) 065
(0026) 25
(0098) 225
(0088) 25
(0098) 450
(1772) 2000 (7874) 2960
(11653) 225
(0088) 2025 (0797) 225
(0886) 2025 (0797)
32
Freezer 210 (698) -10
(140) 540middot (312) 015 (009) 0027 (0015) 687 (121) 641 (113) 065
(0026) 25
(0098) 28
(0088) 25
Jo098) 540
(2125) 2000 (7874) 1580
(6220) 28
(0110) 196
JO772) 224
(088t) 288
(1134)
The output from the simulation includes the entire nodal temperature field heat fluxes at
each node along the centerline heat fluxes from node to node along the steel skin beneath
the door seal and the value for qwallff and qwallcz These heat transfer values and the
nodal temperature distribution are listed in Appendix F
The quantities qwallff and qwallcz are determined by computing the heat fluxes from node to node along the centerline of the section subtracting the one-dimensional flux and then
multiplying by the cross sectional area for that node and summing to give the total heat
transfer rate The primary results are shown in Table 53
Table 53 Wall Simulation Results
Section
The temperature distributions are shown in the following two figures Figure 53 shows
the temperature contour for the fresh food results Figure 54 is the same plot for the
freezer results
Since the geometry of the refrigerator door is similar to that of the wall along the edges the
heat leakage to the food compartments along the door flange can be approximated as being
roughly the same as qwall This approximation of qdoor is a good means of estimating the
two prime contributors to the edge loss for various different refrigerators which may have
slightly different geometries as well as different material properties
33
i
3875
3625
TemplaquogtC)
-e
11111
20
18
16 3375
g 3125 14 -5 2875 ~ 122625 ~
2375~ 102125~
1875 8
1625
1375 6
1125
875 4
625
375
SteeVPlastic Liner Interface
Fig 53 Fresh Food Wall Temperature Distribution
34
i 4875
4625
4375
4125
3875
3625
3375 -
3125e g 2875
2625 ~ 2375 ~ 2125c (I)
1875 ~ 1625
1375
1125
875
625
375
125
Fig 54 Freezer Wall Temperature Distribution
Temp(OC)
20
15
10
5
0
-5
-10
35
53 Wall Edge Simulation to Determine qtube
The wall simulation is modified to include a constant temperature node placed beneath the
steel flange to represent the presence of an anti-sweat condenser tube The simulation is
perfonned for the specific conditions that are typical of the test unit as well as a range of
lateral tube locations For the test refrigerator the tube is located as shown in Figure 55
and is at 35degC (95 OJlt)
Outer Steel Skin
14625 mm 1
Inner Plastic Liner
Fig 55 Tube Location for Simulation
The quantity qtube is detennined by taking the fluxes along the vertical line to the left of
the tube subtracting the one-dimensional flux and then multiplying by the cross sectional
area for that node and summing to give the total heat transfer rate Again the fresh food
compartment and the freezer must be simulated separately to produce a total governed by
Eq (54)
(54)
Program output for the fresh food and freezer simulations is given in Appendix F Table
54 summarizes the results from the model
Table 54 Wall With Condenser Tube Simulation Results
Section Load W iBtubrl
qtubeff 46
(157)
qtubefz 28 (96)
qtube 74 (253)
qtube8ve (ave for 50 cycle time)
37 (126)
36
-I i c IJ
~
r 4875
4625
4375
4125
3875
3625
3375
3125
2875
2625
2375
2125
1875
1625
1375
1125
875
625
375
125
TempfC)
SteeVPlastic Liner Interface
35
30
25
20
15
10
5
Fig 56 Fresh Food Wall Temperature Distribution Including Warm Anti-sweat Tube
37
TempfC)4875
4625
4375
4125
3875
3625
3375 - 31258
2875g 2625fo 2375
3 2125 d vI 1875
~ 1625
1375
1125
875
625
375
125
SteeVPlastic Liner Interface
Fig 57 Freezer Wall Temperature Distribution Including Warm Anti-sweat Tube
38
40
30
20
10
0
-10
The heat fluxes at each node along the vertical line to the left of the tube are also computed
by the simulation This value quantifies the amount of heat that is moving toward the outer
boundary and is used to determine the percentage of heat entering the cabinet For the test
refrigerator this value is 18 for the fresh food compartment and 24 for the freezer
Several more simulation runs were done to find the effect of lateral placement of the tube on
the overall heat transfer and the percentage of heat entering Figure 58 and Figure 59
show the trends that are found
-~ a tUbe ~middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotlmiddotmiddotmiddot=middotmiddot=pmiddotmiddotmiddot=middot-1- =1
middot middot middoti middot middotmiddotmiddotmiddotmiddotmiddotmiddotmiddot bull middotmiddotmiddot i middotmiddotmiddotmiddot middotmiddot middotmiddot ~ middotmiddot
middotmiddotrmiddot-rmiddot 0 lwbeff middotlmiddotmiddot~middot Gmiddottmiddotmiddot9middotlmiddot
i i -0- lwbe i middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotimiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddot fz tmiddotEimiddotmiddot ~G- -~ -q- -
0 5 10 15 20 25 x(mm)
Fig 58 Load Due to Condenser Tube for Various Tube Placements
8
~ - 7
50
a 6
~ 5
~ en 4 ~
pound ~ 3
2
- 26
~ a 24
middots bO
pound 22c ~
~ 20
a = 18sect ~
16 0 5 10 15 20 25
x (mm)
Fig 59 Percentage of Heat Entering Cabinet for Various Tube Placements
39
54 Door Seal Simulation to Determine qseal
Another model is developed for the two-dimensional heat transfer through the door seal
This model is very similar to the one created for the wall section Once again a fIniteshy
difference technique is utilized to detennine the temperature distribution at steady-state
conditions Even though the cross sectional geometry of the seal is simplifIed to a square
with a hollow square with a centrally located cavity no closed-form solution can be
applied Therefore a simulation is needed
The fInite-difference representation of the two-dimensional steady Eq (55) using central
differencing is given by Ozisik (1980)
Ti-lj - 2Tij + Ti+lj + Tij-l - 2Tij + Tij+l = 0 (55) Ax2 Ay2
For this model a square mesh is applied reducing Eq (55) to
Ti-lj + Ti+lj + Tij-l + Tij+l - 4Tij = 0 (56)
x
Fig S10 Seal Simulation Mesh Layout
40
The nodes along the vertical surfaces at x=O and x=20 are subject to the convective
boundary conditions and governed by Eq (57) and Eq (58) respectively
2~xheffol 2~heffo2Ti+lj + Tij-l + Tij+l - (4 + k TiJ = - k To (57)
seal seal
2~heffffl 2~heffff2Ti-lj + Tij-l + TiJ+l - (4 + kseal Tij = - kseal Tff (58)
The nodes along the top and bottom outside surfaces are held at the prescribed temperature
profIles which are detennined from experimental data (see Section 41) The interior nodes
are subject to radiant e~change among themselves and conduction through what is assumed
to be stagnant air A closer look at the model of the hollow interior of the seal is shown in
Figure 511
Fig 511 Seal Cavity Mesh Details
Each interior node corresponds to a single gray surface with assumed emissivity of 09
Viewfactors for all surfaces are computed automatically before the iteration begins For
each iteration the effect of radiation within the enclosure is taken into account by updating
surface radiosities Jij Thus for nodes on interior surfaces an extra tenn is added to the
governing difference equation (Eb is the blackbody radiation)
41
~(J - Eb )1-pound IJ lj
A code written in Fortran is used to perfonn Guass-Seidel iteration of the difference
equations to compute the temperature distribution at mesh nodes (Code listing in Appendix
F) Once again convergence is based on an energy balance applied to the entire section
The iteration is continued until the difference between heat entering and heat leaving is
equal to 01 of the total heat entering the section Table 55 lists the input parameters
used in the model The fresh food compartment and the freezer compartment are simulated
separately
Table 55 Seal Simulation Input
Code Parameter Fresh Food Freezer
Number of nodes along outside edge 20 20
Number of nodes along inside edge 6 6 1 1Lx = fly mm (in) (0039) (0039)
210 210Outdoor ambient temperature degC (oF) (698) (698) 150 105Indoor local ambient temperature degC COF) 590J j509)
Outdoor heat transfer coefficient W m2-K 687 687 (121) (121)(Btuhr-ft2-F)
Indoor heat transfer coefficient Wm2-K 670 641 (118) (113)(Btuhr-ft2-F)
Gasket interior surface emissivity 09 09 03 03Gasket conductivity Wm-K (Btuhr-ft-F) (0173) (0173)
Wall-side Temperature Boundary 1905 - 1977x 1813 - 3475x Condition degC Door-side Temperature Boundary 1913 - 1384x 1852 - 2341x Condition degC
42
The load results are summarized in Table 56 below The program output is listed in
AppendixF
Table 56 Seal Simulation Results
Load W Section (BtuIhr)
10 Qsealff (34)
ljQsealfz (Sn
25qseal (85)
The steady-state temperature distribution is shown in the figures below Figure 512 is the
fresh food simulation and Figure 512 is the freezer simulation The direction of the heat
flow through the section is easily seen from these plots
43
Wall-side Boundary Temperature (C)
~~
I 20
195
i 19t 0
8 ~ 1859 -- ~
isis ~ ampJ gtshy 18 ~
11 ~ S ~ 175~
~ 17
165
x(mm)
Door-side Boundary
Fig 512 Seal Temperature Distribution (Fresh Food)
44
Wall-side Boundary Temperature (C)
Ii 19
185
18i f IQ 5 IQ
175-is-is I s 17j ~
5e 0C= 165
~ ~ 16
155
x(mm)
Door-side Boundary
Fig 513 Seal Temperature Distribution (Freezer)
45
6 DISCUSSION OF RESULTS
The heat transfer values detennined from the experimental analysis and the numerical
simulations are the various components that embody the cabinet load on the refrigerator It
is important to separate cabinet loads from system loads The system load can be thought
of as the total electrical energy consumption of the unit It has four basic components (i)
the compressor (ii) fans (iii) anti-sweat heaters and (iv) defrost heaters The first two
components the compressor and fans are the cost of removing heat from the cabinet This
amount of heat is equal to the cabinet load divided by the COP of the system The typical
energy consumption is shown schematically in Figure 61
System Load (Energy Consumption)
Defrost Heater (averaged over time
cycles every 10-12 hours of compressorrurt-time)
TuneCycle
Fig 61 Refrigerator System Load Graph
In a study done by Turiel and Heydari (1988) the compressor and fans accounted for 84
of the total system load for an 180 cubic foot top-mounted refrigerator Staley (1992)
found this value to be 86 for a similar unit Both of these studies used system analysis to
determine these numbers The energy consumption of the components were monitored
during operation The energy consumption of our test refrigerator can be determined in a
reverse manner from the cabinet load data If a COP of 1 is assumed the test refrigerator
46
compressor and fans accounts for 86 of the energy consumption to cool the cabinet This
compares favorably with the fmdings of Turiel and Heydari (1988) and Staley (1992)
Figure 62 is a schematic of the cabinet loads One possible load that is not included in the
figure is the heat input associated with the defrost drain tube that runs through the back
wall However this term is probably small relative to the other contributors
Cabinet Load
qseal qdoor
qwall
qmullon
qdefrostave
Fig 62 Cabinet Loads Graph
All the loads are determined in this study from either experimental measurements
numerical simulations or both Most of the loads are quasi-steady that is they do not
fluctuate significantly over the cycle time of the refrigerator There are four loads shown in
Figure 61 that are cyclical in nature The three loads that appear only while the
compressor is running are qcomp qfarb and qtube Also the refrigerator is subjected to a
load every time ice build-up is removed by the defrost heaters This load is averaged over
its own cycle time and shown in the graph as qdefrostave
47
61 Comparison of Simulation Results with Experimental nata
The majority of the cabinet loads are detennined from experimental data with the exception
of qseal and qtube The wall and door flange loads aremiddot also found from the numerical
simulation (see Chapter 5) The two-dimensional model detennines the wall-side heat
transfer along the steel skin into the food compartments No model is available to directly
detennine the heat transfer on the door-side However since the flange geometry on the
door-side is similar to the wall the value for qwall is considered to be a good estimate for
qdoor Table 61 gives these values determined from experimental measurements and the
simulation
Table 61 Comparison of Simulation and Experimental Values for qwall and qdoor
Experimental Result W Simulation Result W (BtuIhr) (BtuIhr)
qwallff 28 (96)
28 (96)
qwallz 21 (72)
27 (92)
qwall 49 (168)
55 (188)
ldoorff 33
(112) 28 (96)
qdoorfz 33
(112) 27 (92)
qdoor 66 (224)
55 (188)
The model predicts qwall to within 57 of the experimental value The agreement of the
estimate of qdoor with the experimental value is within 90
Some of the shortcomings in the model used in this investigation are
(i) Only the wall is modeled Ideally the entire region should be considered including the
door and seal (see Figure 11)
(ii) The flange geometry is simplified The steel casing skin in the flange region may bend
in more complex ways Also the plastic liner varies in thickness near the door seal
(iii) The mesh must be unifonn There is no means to vary how fme the mesh can be The
ideal situation would be to have a fine mesh near the edges and a course mesh far from the
seal
48
62 Mullion Analysis
The single largest edg~ load is found in the mullion section (329 of qedge and 94 of
qtol) This load is due to the electric anti-sweat heater installed on the backside of the face
plate The heater is rated at 10 watts and approximately 88 of that input enters the
interior of the cabinet as a thennalload This is probably due to the small surface area
exposed to the room and the low amount of convective heat transfer in the channel between
the fresh food and freezer doors With the heater on 88 watts is measured enter the food
chambers With the heater off only 16 watts enters the interior The addition of the
heater increases the mullion load 55 times Generally it is not necessary to use the
mullion heater at all times However for the test environment the heater nearly all the time
to eliminate sweating under the laboratory conditions
63 Seal Analysis
The heat conduction directly through the seal accounts for the smallest portion of the edge
loss (94 ofqedge and 27 of qtol) The numerical model to detennine these values uses
a simplified representation of the complex cross sectional geometry of an actual door seal
The various air pockets are reduced to a single hollow void There is no experimental data
to verify the model However the numbers and trends resulting from the simulation are
reasonable
64 Anti-sweat Condenser Tube Analysis
Thennocouple drag tests were perfonned to give insight into the nature of the temperature
profIles at the wall steel flange with the presence of an anti-sweat condenser tube The wall
heat transfer simulation model was modified to include the effect of this tube The heat
conduction to the interior increased by 76 at the wall flange region The amount of
additional loading due to the tube depends on several parameters location of the tube
temperature of the circulating refrigerant and local wall geometry Although the model is
flexible enough to handle vari01~S temperatures and limited geometrical changes only the
influence of tube position was investigated As the tube is moved towards the interior the
load increases For the test refrigerator about 20 of the heat flow was directed to the
interior compartments primarily along the steel skin
49
6S Overall Cabinet Load
The overall cabinet load is defined as a sum of three parts
(61)
The edge load is
qedge = qwall + qdoor + Qseal + Qrnullon + qtubeave (62)
where
qwall
qtubeave
heat input due to the conduction along the wall steel flange
heat input due to the conduction along the door steel flange
heat conduction directly through the door seal
heat input due to conduction in the mullion region with the additional input from anti-sweat heater
heat input due to cabinet anti-sweat condenser tube averaged over the cycle time
heat input due to cabinet anti-sweat condenser tube
qmulloff heat input due to conduction in the mullion region electric heater off
The terms of Qrnisc are defined as
qmisc = qfanave + qdefrostave + qcompave (63)
where
qfanave heat input from the evaporator fan averaged over the cycle time
qdefrostave heat input from the defrost heaters averaged over defrost cycle time
qcompave heat input from elevated exterior walls near the running compressor
Table 62 presents the overall cabinet load analysis results
50
Table 62 Overall Cabinet Loads
Load W Load Btuhr Total
qlD 550 1876 591
qedge 265 903 285
Qwall 49155 167 188 53
Qdoor 66155 2251 188 71
Qseal 25 85 27
Qmullon 88 300 94
Qtubl ngt 37 126 40
qmisc 116 395 124
Qfanave 46 157 49
Qdefrost ave 50 170 54
qcomoave 20 68 21
qtot 931 3174 100
Simulation Results
All loads are detennined experimentally with the exception oflsea1 and qtubeave The
values for qwall and qdoor are detennined from both experimental data and numerical
simulations Edge loss per unit length along fresh food perimeter is 29 Wm (30 Btuhrshy
ft) the loss per unit length along the freezer perimeter is 44 Wm (46 Btuhr-ft) and the
loss along the mullion section is 123 Wm (128 Btuhr-ft) with the heater on and 22 Wm
(23 Btuhr-ft) with anti-sweat heater off
The largest single load is the one-dimensional conduction through the walls and doors
The edge load comprises 285 of the total a significant portion The largest edge load is
due to the electric anti-sweat heater that is installed in the mullion section The smallest
edge load is due to the heat conduction through the fresh food and freezer door seals The
losses at the wall-side and door-side flange regions account for 53 and 71 of the total
load respectively These could be considered together since the pathway of heat transfer is
very similar If that were the case the sum of qwall and qdoor would be the second largest
contributor to the overall cabinet load The influence of an anti-sweat condenser tube is
reflected in the value of qtubeave Although this additional load is larger than qwall it must
be integrated over the refrigeration cycle timewhich is 50 of the cycle time for the test
unit The tube boosts the heat transfer along the wall flange by 76
51
To round out the cabinet load three miscellaneous loads are considered The evaporator
fan motor produces a heat load within the cabinet which is considered to be equal to the
power rating of the fan The automatic defrost feature is another thermal load that is
cyclical appearing about every ten to twelve hours of compressor runtime The fmalload
is due to the elevated exterior skin temperature near the compressor when it is running All
three of these loads are averaged over their cycle times for comparison with other quasishy
steady loads As a total qmisc represents 124 of the overall cabinet load
Opportunities to decrease the one-dimensionalload are available The emphasis has been to
develop super-insulations to be installed in the refrigerators Some being considered are
vacuum panels aerogels and vacuum packed powder insulations The disadvantages of
this improvement lies within the need to develop a cost-effective technique for fabricating
and installing such technologies compatible with high-volume manufacturing Also edge
losses and panel connection losses must be minimized due to the difficulty in making a
panel the size of refrigerator interiors Reliability of the seal and perfonnance of the outer
envelope need to be ensured over a long period of time ie the expected life of the
product
The possibilities of reducing the loads along the edge of the refrigerator aperture are
somewhat less apparent One method of reducing quasi-steady heat conduction along wall
and door flanges is to raise the inside cabinet wall temperature by minimizing interior film
surface heat transfer coefficients This could be accomplished by the use of low-emissivity
surfaces on the interior walls or on sections nearest the edges The need for an anti-sweat
device for the perimeter is also eliminated supplying a two-fold savings by reducing the
cabinet ioad and the system energy consumption The need for an electric mullion heater
might also be done away with by the same means The drawback again would be to make
such modifications acceptable and cost-effective for manufacture
The remaining miscellaneous loads provide some chance for improvement If the
efficiency of the fans is increased the energy use of the refrigerator can be reduced The
option of moving the fan motor outside the cabinet leads to other problems The motor
shaft must pierce the wall providing another path for heat leakage Also frost built-up on
the shaft would be a costly and difficult problem to eliminate If the compressor and
condenser were located near the top of the refrigerator they can operate more efficiently
Heat can be more readily convected away eliminating the need for the condenser fan
(Turiel and Heydari 1988) Frost fonnation in the freezer varies significantly depending
52
on the ambient conditions and the freezer usage The defrost cycle could be made more
energy efficient with the addition of adaptive controls All of these improvements would
require redesign of the product and the manufacturing process This is a very expensive
alternative which would need to be justified by the associated energy savings
53
7 SUMMARY OF CONCLUSIONS
The following is a list of the important findings produced from this study
(i) The edge loading accounts for a significant portion of the total cabinet load For the
test unit used in this study an 18 cubic foot top-mount refrigerator this load was
approximately 30 of the total load The load includes losses along the wall and door
flanges conduction through the door seal mullion loading with an electric anti-sweat
heater on and additional thennal input from an anti-sweat perimeter condenser tube
(ii) The presence of an electric anti-sweat mullion heater boosts the mullion loading by
a factor of approximately 5
(iii) The presence of an anti-sweat condenser tube around the perimeter of the refrigerator
increases the wall flange load by approximately 75
(iv) The presence of the door air damt reduces the temperature difference across the door
seal to 35 of the temperature difference between the interior and exterior
environments
(v) The hypothetical elimination of the additional load due to the electric anti-sweat
mullion heater reduces the edge loading to approximately 22 of the total cabinet
load
(vi) The hypothetical elimination of the load due to the anti-sweat condenser tube reduces
the edge loading to approximately 25 of the total cabinet load Ifboth anti-sweat
devices were not needed the edge loading would be further reduced to only 17 of
the total
(vii) During the course of this investigation it was concluded that the experimental and
numerical methods developed are applicable to most refrigeratorfreezers that are
produced today
t The portion of the door liner that extends into the cabinet along the wall
54
REFERENCES
Braswell A 1988 Impact of CFC Regulations on the Air Conditioning and Refrigeration Industry International Jow-nal ofRefrigeration Vol 11 No6 p 385
Cabot Corporation 1987 CAB-O-SIL Fumed Silica Properties and Functions Tuscola n pp 12-15
Clausing A M 1983 Natural Convection Correlations for Vertical Surfaces Including Influences of Variable Properties ASME Jow-nal ofHeat Transfer Vol 105 No 1 pp 138-143
Incropera FP and Dewitt DP 1985 Fundamentals ofHeat and Mass Transfer Second Edition John Wiley and Sons New York
Ingersoll LR Zobel OJ and Ingersoll AC 1954 Heat Conduction with Engineering and Geological Applications McGraw-Hill Book Company New York
Little AD Inc 1982 Refrigerator and Freezer Computer Model Users Guide Cambridge Massachusettes
Micropore International Ltd Microtherm Thermal Insulation Worcestershire England Section 1
Nix GH Lowery GW Vachon RI and Tanger GE 1967 Direct Determination of Thermal Diffusivity and Conductivity with a Refined Line-Source Technique Progress in Astronautics and Aeronautics (Vol 20) Thermophysics ofSpacecraft an Planetary Bodies Academic Press New York pp 865-878
Nix GH Vachon RI Lowery GW and McCurry TA 1968 The Line-Source Method Procedure and Iterative Scheme for Combined Determination of Conductivity and Diffusivity Thermal Conductivity Proceeding of8th Conference
Ozisik MN 1980 Heat Conduction Wiley-Interscience Publishing New York pp 486-487
Staley D 1992 Personal Communication Graduate Research Assistant University of Illinois Urbana
Turiel I Heydari A 1988 Analysis of Design Options to Improve the Efficiency of Refrigerator-Freezers and Freezers ASH RAE Transactions Vol 94 Part 2
Van der Held EFM and Van Drunen FG 1949 Physika Vol 15 No 10 p 865
White PM 1988 Heat and Mass TranSer Addison-Wesley Publishing Reading Mass pp 145-160
55
APPENDIX A FUMED SILICA INVESTIGATION
A ~ 1 Introduction
Fumed silica is a micro-porous powder comprised of submicron particles of amorphous
silica bonded together in a cellular structure Several grades of silica are available offering
a selection ofdifferent grain sizes and chemical treatments Fumed silica is commonly used
to provide thickening thixotropy suspension and other related properties in liquid
systems In dry systems it is used to promote free flow frictionizing and anti-blocking
properties Thus it is a versatile additive in materials such as inks coatings adhesives~
and silicon rubber (Cabot Corporation 1987)
The thermal insulating properties of this material have been somewhat less widely applied
however fumed silica as an insulation displays some interesting properties Fumed silica
insulations are commercially available and have become a more popular material for certain
specific applications In this section the results of an investigation of the thermal
properties of one type of fumed silica is presented
A2 Thermal Properties
As an insulator fumed silica uses the microporous principle to reduce thermal conduction
to the theoretically lowest possible levels (Micropore International Ltd 1988) Most
conventional insulations rely upon voids normally occupied bj alt aS the meanS ot
minimizing heat transfer through the material Therefore it is important to maintain these
voids for maximum insulation Fumed silica is comprised of tiny spheres with diameters
of the same order of magnitude as the mean free path of the molecules in the air
Therefore when these spheres are packed closely together gaseous conduction and
convection are minimized The cell size is sufficiently small to keep convective currents
from forming and to trap gas molecules to rebound elastically thereby not imparting their
energy to slower moving molecules In addition solid conduction is minimized by the fact
that silica is a material with intrinsically low thermal conductivity These unique properties
make fumed silica an attraCtive alternative to conventional insulations
56
A3 Experimental Method
Thennal conductivity and thennal diffusivity are the properties detennined from our
experimental study Many methods exist for establishing the thennal properties of a given
substance Both steady-state and transient procedures are available The hot-wire method
is a the transient procedure used in this study
The practical form of the hot-wire method is given by Van derHeldand Van Dronen
(1949) who used it to detennine conductivities of liquids Nix et al (1967) elaborated to
give a method for the simultaneous detennination of both thennal conductivity and thennal
diffusivity Therefore it is possible to detennine both conductivity and diffusivity by
passing a known amount ofcmrent through a heater wire embedded in the test material and
recording the temperature at a point on the wire and at a fixed point from the wire over the
period of the test From the temperature history of the point contiguous to the hot-wire the
conductivity can be detennined directly From the temperature history of the point at a
fixed distance from the hot-wire the diffusivity may be computed Both procedures are
outlined in the following section
A4 Theory
The temperature at any point in an infinite solid containing a line heat source of constantshy
rate is a function of the position time from initiation the thennal conductivity of the
material and the magnitude of the source This is shown mathematically by Ingersoll et aI
(1954) The cylindrical temperature field is expressed as
T=~l- exp-x2) dx (Al)21tk x
II
In series fonn
(A2)T=~[-amp-lnp+L-L+L_ ]21tk 2 21 4middot2 63
57
where
q = Heat input per unit length of wire [W1m]
k = Thennal conductivity of the material [Wm-K]
a = Thennal diffusivity of the material [m2s]
t = Elapsed time from heat liberation [s]
r = Radial distance from line-source [m]
Ce = Eulers constant (05772157 )
The temperature change between two times tl and t2 is accurate to better than one percent if
the value of ~ is less than 016 for a point very close to the line-source
(A3)
Equation (A3) is used in this case to detennine the thennal conductivity since the
diffusivity a and the radial distance T no longer appear in the relation Therefore
knowing the temperature at two different times during the test gives the conductivity
directly given that the value of ~ remains small This is achieved by choosing a point very
near if not contiguous to the hot-wire itself In our study a graphical method is used to
detennine the conductivity If the temperature versus the natural logarithm of the time is
plotted a straight line should be seen whose slope is equal to q4nk
Once the conductivity of the material is detennined the diffusivity can be found by the
method proposed by Nix et aI (1968) The temperature at a fixed and known distance
from the hot-wire must be monitored over the time period of the test Now since ~ gt 016
the diffusivity does not drop out of Equation (A2) Rewriting Equation (A3) as
(A4)
where
~2 ~4 ~6 ]r(~)= [ -~-ln~+---+-- (A5) 2 211 4middot2 6middot3
58
therefore (A6)
Using the temperature at the fixed location as an input Equation (A6) can be solved iteratively by means of Newton-Raphson technique to find the parameter ~ and thereby
yielding the thermal diffusivity a
AS Test Apparatus
Figure A1 is a sketch of the test apparatus used to collect thermal property data This
device provides a wide range of silica densities for packed tests Each half of the apparatus
is packed separately to the same density and then pressed together sandwiching the heater
wirethermocouple assembly between them
Remove bottom plate and press together with right half
Insert heater wirethermocouple assembl)
Remove bottom plate and press together with left half
Compact both halves to same density
Fig AI Fumed Silica Test Apparatus
Prior to loading the unpacked silica into the test cylinders the mass is carefully recorded
Each test cylinder has graduated marks to allow the volume of the sample to be computed
The density is then computed from the measured mass and volume At higher densities it
59
is sometimes necessary to load and compact several times Figure A2 is a schematic of the
heater wirethermocouple assembly and the entire test facility
Switch
Ammeter
Power Source
Cylindrical Test Section
Thermocouple for Conductivity
Data Acquisition System
Thermocouple for Diffusivity
Fig A2 Fumed Silica Test Facility Schematic
The heater wire used for all tests is 30 A WG nichrome wire with a nominal resistance of 2214 Wm Both thermocouples are type T 36 A WG Once the test sample is in place
the switch is closed allowing cUITent to pass through the heater wire The heat input per
unit length of the wire is determined from
(A7)
where q = Heat input per unit length of wire [Wm]
I = The input cUITent [Amps]
R = Heater wire resistance per unit length [Wm]
60
Knowing the heat input per unit length the temperature contiguous to the heater wire and
the temperature at a fixed distance from the heater wire over the duration of the test eqs
(A3) and (A6) can be solved This yields the conductivity and diffusivity respectively
A6 Results
All results presented in this section are from tests petfonned with a material sample donated
by Cabot Corporations Cab-O-Sil Division The silica is an untreated sample EH-5 with
a bulk density of 25 Ibsft3 and a nominal particle diameter of 70 angstroms Several tests
are petfonned at various densities The thermal conductivity is determined graphically as described above while the diffusivity is determined using a Fortran code to pe~orm the
Newton-Raphson iteration also outlined in Section A4
A total of seven different bulk densities are tested Each test consists of three runs at three
different power levels The temperature history is recorded for both thermocouples
Figure A3 is a plot of the temperature for the duration of a typical test for unpacked silica
70~--~----+----r----~-----~----+----r
10001
middot middot middot o 05 Ampsmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddot o 04 Ampsi ~ i
I i I I i oo~ct 60 IIJatr-T50
1 LL~40
1 ~ 1 010 1 ltgtom
JPi i30 i 0I1 o 03 Amps 1 I I
20~--~----+----r----~-----~----+----r
-10 o 10 20 30 40 50 60 70 Time (sec)
Fig A3 Time vs Temperature for Unpacked Run
61
To graphically detennine the thennal conductivity the temperatme data must be plotted
against the natural logarithm of time Figure A4 gives this plot along with the equations
that represent linear curve-fits to the straight portion of each curve
70~----~--------+------+--------~----~----~--------+-----~
60 ~ =l-LL-~--o T ~ 86839 ~ 1376 ~(t) I
50 ---f--H-deg--tfjtshy ~ T =11108 + 97346 m(t)
40 IT_oroJ~-
30 middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotImiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotsectmiddotmiddotmiddotmiddotmiddotImiddotmiddotmiddotmiddotmiddotmiddotmiddot~middotmiddotmiddotmiddot109~~Q9 T= 18431~ + 493 ~(t) 0
~ e i i i
20~----~--------+------+--------~---------~~----+------r
05 1 15 2 25 3 35 4 45 In (time)
Fig A4 Natural Log Time vs Temperature for Unpacked Run
All three curves should yield the same conductivity for the sample The conductivity is
detennined from the following relation
k= 12R (A8)4n(slope)
Table AI gives the average conductivity for each density level This is the average for the
three input cmrents used These results are also shown graphically in Figure A5
62
Table AI A verage Fumed Silica Conductivity for Various Bulk Densities
est
1
2
3
4
5
6
7
0024
0023
0022 -~ ct 0021
~ e 002
~
0019
0018
0017
i
~i
I I I I Imiddotmiddotmiddot_middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotimiddot_middotmiddot middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotimiddot-middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot
1i111
~ ~ iii
_I_1_1_1
I I I I I middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot middotmiddotmiddotmiddotmiddotmiddotmiddotfmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddot -r-t-o-rldegoo---shy
25 3 35 4 45 5 55
Density (lbsff)
Fig AS Conductivity vs Bulk Density
From the temperature data collected from the second thennocouple the thennal diffusivity
is computed (see Section A4) This thennocouple lies 3 mm (0118 in) from the heater
63
wire The output from the diffusivity iteration is provided in Table A2 A graphical
representation is given in Figure A6
Table A2 Average Fumed Silica Diffusivity for Various Bulk Densities
Test
Average Diffusivity m2s (ft2Jhr)
1 210 x 10-7 (000813)
2 166 x 10-7 (000643)
3 159 x 10-7 (000616)
4 155 x 10-7 (000600)
5 153 x 10-7 (000592)
6 No Data Available
7 151 x 10-7 (000585)
00085 -+----+-----f----+----+----+--_+_
I
middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1 ~0008
I I I I ~
I middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotfmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot Tmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot ~ 00075
~-shyf i ~ ~ ~ i ++middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotfmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot0007 i iii
~ rn ~ ~ i i~
(jj bullbullbullbullbullbull1bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullJLbullbullbullbullbullbullbullbullbullbullj ~ 00065o ~ middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot0006
I I I 00055 -+----+-----f----+----+----f--_+_
25 3 35 4 45 5 55
Density (lbsff)
Fig AS Diffusivity vs Bulk Density
64
A7 Conclusions
The primary conclusion from this experimental study is the fact that the thennal insulating
properties of fumed silica powder increase as the bulk density of the material increases
Although this study presents a limited range of density values the trends that were
expected are seen to be true The conductivity values are expected to reach and even
surpass those of CFC-blown foams that are used in household refrigerators Further
testing is needed to provide data that supports this expectation In addition testing in this
study was strictly limited to a single variety of silica This particular type of silica is not
necessarily the best candidate for thermal insulation applications Silica powders are by
nature hydroscopic This affinity for water has adverse effects on its thermal insulating
properties However silica powders are now produced with a special treatment which
transforms the material into a hydrophobic material Therefore if these new materials
maintain the thermal properties and density trends of the hydroscopic type they become
even more preferred insulators Once again data needs to be obtained to support this
notion Fumed silica offers a competitive alternative to the existing CFC-blown foams
without the obvious environmental drawbacks It is completely inert recyclable and
reusable It also competes well when comparing cost values CFC-blown foams are
between 003 - 007 $ft2_R-Value whereas fumed silica powder are between 005 -025
$ft2-R-Value The discrepancies are close enough to merit true consideration
AS Thermal Diffusivity Newton-Raphson Iteration Source Code
program difsivty implicit none double precision condqtime(lOO)temp(lOO)guessradiusalpha
+ dif(lOO)sumavedifgcurrentmasslengthpi + density integer nikrun OPEN (2file=Oiffusivityoutlposition=rewind) OPEN (3file=Oiffusivityinposition=rewind) OPEN (4file=Oiffusivityout2position=rewind)
print Enter input current in amps readcurrent printEnter calculated conductivity in Wm K readcond print Enter thermocouple distance in meters readradius print Enter mass of sample in grams readmass print Enter compacted length of sample in em readlength print Enter number of timetemperature data points
65
c
readn 5 print enter initial quess for beta
readquess c
pi=31415927 q=currentcurrent2214 density=(mass1000)laquopi4)(003844)(lenqth100raquo
c c check to see if converqence will occur c print Enter data point l c print (time and temp with a blank separatinq the two) c readtime(1)temp(1) c call diffus(condqtime(1)temp(1)quessradiusalphaq) c printinitial q=q c if (abs(q) qt 05) then c qoto5 c endif c
do 10 i=1n read(3) time(i)temp(i)
10 continue c
print print Input Current= current print write(2) Input Current= current write (2 )
c sum=OO do 20 k=1n call diffus(condqtime(k)temp(k)quessradiusalphaq) print Diffusivity for data pointk =alpha write(2) Diffusivity for data pointk =alpha write(4) alpha dif(k)=alpha sum=sum+dif(k)
20 continue c
avedif=sumn c
print print print INPUT print Conductivity=cond Wm K print Heater Input=q Wm print Thermocouple Distance=radius m print- print OUTPUT print Sample Density=density kqm3 print Averaqe Diffusivity=avedifmiddot m2s
c write(2) write(2) INPUT write(2) Conductivity=cond Wm K write(2) Heater Input=q Wm write(2) Thermocouple Distance=radius m write (2 ) write(2) OUTPUT write(2) Sample Density=density kqm3 write(2) Averaqe Diffusivity=avedif m2s
c c
pause stop
66
end
subroutine diffus(condqtimetempguessradiusalphag) implicit none double precision condqtimetempbeta(100)radius
+ f1f2f1pf2ptempf2tempf2pggppialphaCe + signfactol integer jkmn
c Ce=5772157 pi=31415927 beta (1) =guess tol=l j=l
c c begin Newton-Raphson iteration to find beta and ultimately alpha c
while (tol gt 0001) c print betaj =beta(j)
f1=-Ce20 - log(beta(j)) flp=-l Obeta (j) f2=00 f2p=00
c c start loop to compute the summations for f2 and f2 prime
do 10 k=2162 m=k2
c this loop gives the factorial for the kth term fac=10 do 5 n=lm
fac=facn 5 continue
sign=(-1)laquok+2)2) tempf2=laquobeta(j)k)sign)(kfac) tempf2p=laquobeta(j)(k-1))sign)fac f2=f2+tempf2 f2p=f2p+tempf2p
10 continue
c c compute the value of G and G which are both functions of beta c these will be used to update beta in the Newton-Raphson iteration c where beta(n+1)= beta(n)- GG
g=laquo20picondtemp)q)-(f1+f2) gp=- (flp+f2p)
c print g=g c here we check to see if the convergence criterion suggested c by Nix is met for the initial beta chosen if not we must jump out of loop c if (j eq 1) then c if (abs(g) qt 05) then c printconvergence not satisfied c printtry a s~aller guess for beta c return c endif c endif c c update the value of beta and compute a tolerance value c that will be used to check for convergence
beta(j+1)=beta(j)-(ggp) tol=abs(beta(j+1)-beta(j))
67
j=j+1 c protect against infinite looping
if (j eq 100) then goto 101
endif repeat
c c if the iteration converges then compute the value for diffusivity
alpha=(10(40timeraquo(radiusbeta(jraquo2
c c
101 return
68
APPENDIX B ONE-DIMENSIONAL SIMULATION SOURCE CODE AND OUTPUT
B1 Source Code
CPROGRAM FrigWall--Steady-State Heat Conduction with Convective and CRadiative Heat Transfer from interior and exterior surfaces C Programmed by AM CLAUSING
LOGICAL SI DIMENSION RA(2)XNU(2)R(2)H(2)HR(2)TF(2)TW(2)DT(2) COMMON AXLWXLC(2)HC(2)T(2)XKWBETANMAXSIE(2)SIGMA
CDetermine- direction of output read and print input data NCASE=l
1 CALL DATAIN(NCASEIUOUT) NCASE=NCASE+1 QOLD=O TW(1)=T(1)+1(T(2)-T(1raquo TW(2)=T(2)-1(T(2)-T(1raquo
CCalculate wall resistance RW=XLWXKWA DO 3 N=lNMAX DO S J=12
CCalculate the radiative equivalent heat transfer coefficients HR(J)=SIGMAE(J)(T(J)2+TW(J)2)(T(J)+TW(Jraquo
C Calculate the film temperatures TF(J)=(T(J)+TW(Jraquo2
CCalculate the convective heat transfer coefficients CALL GASPT(lTF(J)RHOXMUXKCPGRBPRIER) DT(J)=ABS(TW(J)-T(Jraquo RA(J)=PRGRBXLC(J)3DT(J) IF(RA(J) LT1E9) THEN
XNU(J)=0S2RA(J)2S ELSE
XNU(J)=09RA(J) 3333 ENDIF H(J)=XNU(J)XKXLC(J) IF(HC(J) NE O) H(J)=HC(J)
CCalculate surface resistances R(J)=l(H(J)+HR(JraquoA
S CONTINUE CCalc~late total resistance heat flow rate and surface temperatures
RT=R(1)+R(2)+RW Q=(T(2)-T(1raquoRT TW(l)=T(l)+QR(l) TW(2)=T(2)-QR(2)
CCheck for convergence If solution has converged exit loop ERRQ=ABS(Q-QOLD)100Q QOLD=Q IF(ERRQLT OS) GOTO 7
3 CONTINUE 7 WRITE (IUOUT 101) Q ERRQ (H (J) HR (J) RA (J) XNU (J) TW (J) DT (J) R (J) RT
2 J=l2) 101 FORMAT( Q =F61 W10XERRQ =FS2 T12 hconvT22hradT33
2 RaT44NuTS2 TsurT62 DeltaTT72RRtotT10 [Wm2-KjT20 2 [Wm2-KjTS3 [KjT63 [Kj InsideF72F92E133F91 2 F101F91F113 OutsideF62F92E133F91F101F91F113) DO 9 J=l2 IF(HC(J) NE bull O) WRITE (IUOUT 103) J
9 CONTINUE 103 FORMAT( NOTE hconv(I1 ) was specified not calculated)
GOTO 1 END
69
C SUBROUTINE DATAIN(NCASEIUOUT) LOGICAL SI COMMON AXLWXLC(2)HC(2)T(2)XKWBETANMAXSIE(2)SIGMA DATA AXLWXKWXLCHCTENMAXSIGMA2990360245315 2 20277297 959510567E-8
CDefinition of NAM NAMELIST NAMAXLWXKWXLCHCETNMAXBETASI CHARACTER FNAME60CDATE9CTIME8 PARAMETER (IUIN=7)
CIF First Case Open Files Write Program Description and Date IF (NCASEEQ 1) THEN
WRITE (6 100) 100 FORMAT( TYPE NAME OF INPUT DATA FILE)
READ( (A) ) FNAME COpen input and output files
OPEN (7FILE=FNAME) REWIND 7
C OPEN (10FILE=Plots-FNAME) C WRITE(6122) Plots-FNAME C122 FORMAT( COMMA DELIMITED PLOTTING FILE IS A)
WRITE(6118) 118 FORMAT (T10 DIRECT OUTPUT TOT20 SCREENT36 Type 6
2 T20 OUTPUT FILET36 Type 8T20 PRINTERT36 Type 9) READ() IUOUT IF(IUOUTEQ8) THEN OPEN (8FILE=Answers-FNAME) WRITE(6120) Answers-FNAME
120 FORMAT( OUTPUT WILL BE WRITTEN IN FILE A) ENDIF CALL DATE(CDATE) CALL TIME(CTIME)
CWrite Program Description and Date WRITE(IUOUT102)CDATECTIME
102 FORMAT( Program FrigWallT60 Date A10 Version 8 August 1991T60 2 Time A9 Programmed by AMClausing) ENDIF
CRead and Write Input Data READ(IUINNAMEND=999) WRITE (IUOUT 104) NCASETXLCEXLWXKWA
104 FORMAT ( CASE NUMBER 12 2 Ambient Temperatures IK] InsideF616X OutsideF61 2 Characteristic Lengths 1m] InsideF626X OutsideF62 2 Surface Emissivities8X InsideF626XOutsideF62 Wall
Thickness 2 F63 mT27 ConductivityF63 Wm-K2x AreaF52 m2) RETURN
999 WRITE (IUOUT 199) 199 FORMAT ( ALL INPUT DATA HAS BEEN PROCESSED) 991 CLOSE(10)
IF(IUOUTEQ 8) CLOSE(8) STOP END
C SUBROUTINE GASPT(NGASTRHOXMUXKCPGRBPRIER)
C PROGRAMMED BY A M CLAUSING VERSION APRIL 1982 C PROPERTIES OF GASES IN SI UNITS(TGTO) OR ENGLISH UNITS(TLT O) C FUNCTIONAL REPRESENTATIONS USED ARE OF THE FORM Y=ATB C ARRAYS A AND B CONTAIN THE RESPECTIVE CONSTANTS C INPUT C NGAS - NGAS=l IS AIR NGAS=2 IS NITROGEN C T ---- ABSOLUTE TEMP (K) OR NEGATIVE OF ABSOLUTE TEMP (R) C OUTPUT C RHO -- DENSITY (KGM3) OR (LBMFT3)
70
C XMU -- VISCOSITY (KGM-S) OR (LBMFT-S) C XK --- THERMAL CONDUCTIVITY (WM-K) OR (BTUHR-FT-R) C CP --- SPECIFIC HEAT (JKG-K) OR (BTULBM-R) C GRB -- GBETAXNU2 (1M3-K) OR (1FT3-R) C PR --- PRANDTL NUMBER (DIMENSIONLESS) C IER -- ERROR PARAMETER C INFORMATIVE ERRORS C IER=l --- GAS NUMBER DOES NOT EXIST GAS IS ASSUMED TO BE AIR C IER=2 --- TEMPERATURE OUT OF RANGE OF PROPERTY SUBROUTINE C RESTRICTIONS C NGAS -- MUST BE l(AIR) OR 2 (NITROGEN) C T ----- T MUST LIE BETWEEN 150K AND 2100K FOR AIR AND BETWEEN C 83K AND 450K FOR NITROGEN RANGES ARE SPECIFIED WITH ARRAY R C
DIMENSION A(152)B(152)R(32) DATA A36411764E-61423E-399084178E20123 235064914E-62494E-329944985E195930 3 432491E-81239E-415534379E201137 4351618E-6221E-31031408E2084130 DATA B-1005814913800316-4639-09685 2 -999642981521962-4284023930 3 -10469389466-079-5102-0872 4 -10058058 834500239-4636-0265230 DATA R150400210083160450 IER=O IFlaquoNGASGTO) AND(NGASLT3raquo GO TO 1 IER=l NGAS=l
1 1=1 TP=T IF(TLT bullbull O) TP=-T18 IFlaquoTPLTR(lNGASraquo OR (TPGTR(3NGASraquo) IER=2 IF(TPGTR(2NGASraquoI=7 RHO=A(INGAS)TPB(INGAS) XMU=A(I+1NGAS)TPB(I+1NGAS) XK=A(I+2NGAS)TPB(I+2NGAS) CP=A(I+3NGAS)TPB(I+3NGAS) GRB=A(I+4NGAS)TPB(I+4NGAS) PR=A(I+5NGAS)TPB(I+5NGAS) IF(TGT O)RETURN RHO=RHO1602 XMU=XMUl 488 XK=XKl 731 CP=CP4187 GRB=GRB6357 RETURN END
B2 Output
Program FrigWal1 Version 8 August 1991 Programmed by AMClausing
Date Time
05-MAR-92 200227
CASE NUMBER 1 - Fresh Food Walls
Ambient Temperatures IK] Inside 2770 Outside 2940 Characteristic Lengths 1m] Inside 030 Outside 150 Surface Emissivities Inside 095 Outside 095
71
Wall Thickness 0045 m Conductivity 0027 Wm-K Area 242 m2
Q = 209 W ERRQ = 002
hconv [Wm2-K]
Inside 1 98 Outside 130
hrad [Wm2-K] 461 544
Ra
0488E+07 0459E+09
Nu
244 761
Tsur [K]
2783 2927
DeltaT [K] 13 13
RRtot
0077 0075
CASE NUMBER 2 - Fresh Food Door
Ambient Temperatures [K] Inside 2770 Outside 2940 Characteristic Lengths [m] Inside 030 Outside 150 Surface Emissivities Inside 095 Outside 095 Wall Thickness 0040 m Conductivity 0040 Wm-K Area 089 m2
Q = 117 W ERRQ = 001
hconv [Wm2-K]
Inside 218 Outside 144
hrad [Wm2-K] 463 542
Ra
0714E+07 0690E+09
Nu
269 843
Tsur [K]
2789 2921
DeltaT [K]
19 19
RRtot
0114 0113
CASE NUMBER 3 - Freezer Walls
Ambient Temperatures [K] Inside Characteristic Lengths [m] Inside Surface Emissivities Inside
2630 030 095
Wall Thickness 0056 m Conductivity 0027
Outside Outside Outside
2940 150 095
Wm-K Area 110 m2
Q = 14 3 W ERRQ = 003
hconv [Wm2-K]
Inside 226 Outside 143
hrad [Wm2-K] 397 542
Ra
0990E+07 0684E+09
Nu
292 841
Tsur [K]
2651 2921
DeltaT [K]
21 19
RRtot
0067 0061
CASE NUMBER 4 - Freezer Door
Ambient Temperatures [K] Inside 2630 Outside 2940 Characteristic Lengths [m] Inside 030 Outside 150 Surface Emissivities Inside 095 Outside 095 Wall Thickness 0040 m Conductivity 0040 Wm-K Area 034 m2
Q = 81 W ERRQ 002
hconv [Wm2-K]
Inside 259 Outside 1 64
hrad [Wm2-K] 400 538
Ra
0169E+08 0124E+10
Nu
333 967
Tsur [K]
2666 2906
DeltaT [K] 36 34
RRtot
0117 0110
72
__ ___
APPENDIX C TEST REFRIGERATOR DESCRIPTION
The test refrigerator is a White-Westinghouse model RT193MCWO 186 cubic foot
capacity top-mounted unit It is equipped with full automatic defrost The cycle time for
this unit is approximately 50 The unit also has two anti-sweat devices An electric
heater is located in the mullion region to prevent frosting between the freezer and the fresh
food compartments Also a condenser tube runs around the entire outside perimeter of the
unit embedded beneath the steel all flange Figure C1 illustrates these features
~1-- 0787 m (31)__
~ r_----------------------
1581 m
Fig CI Location of Anti-sweat Devices and Overall Dimensions of Test Refrigerator
73
Under test conditions the refrigerator and freezer are filled with milk containers full of
water These containers provide sufficient thennal mass to minimize temperature
fluctuations dming experimental runs Twenty gallons are present in the fresh food
compartment and 6 gallons are in the freezer
Figures C2 through C5 give the detailed dimensions of the fresh food compartment and
the freezer All dimensions are in millimeters and are obtained directly from the unit
Dimensions are estimated to be accurate to within plusmn 3 mm
697
762
1
305
717
Fig C2 Fresh Food Compartment Interior Dimensions
74
1127
Fig C3 Fresh Food Door
75
675
381
Fig C4 Freezer Interior Dimensions
432
Fig CS Freezer Door
76
APPENDIX D DATA ACQUISITION AND CONTROL SYSTEM
Corresponding with the construction of the experimental apparatus was the purchase and
assembly of a data acquisition and control system The system itself was designed to meet
the needs of a variety of experiments and is therefore a very flexible system
The system consists of six DC power supplies a data acquisition chassis a computer a
rack ofdigital relays and a variety of analog and digital inputs and outputs A data
acquisition and control software package orchestrates the interactions between these
components and regulates outgoing signals as well as providing data storage
External signals enter the system through a Keithley 500P data acquisition chassis These
signals consist of voltage and current measurements from the power supplies as well as
thermocouple voltages At present a total of ninety-six thermocouple inputs are available
with an optimal resolution of +0012 degrees C The addition of more thermocouple input
boards could expand the capability to 128 inputs Also special boards can be installed to
allow strain gauge thermistor digital or other standard data acquisition functions The
Keithley chassis can contain a total of nine interface boards and its l~bit AID conversion
allows for very high resolution
The six DC power supplies consist of two Hewlett Packard and four Sorensens with a
combined power of 7560 watts The Sorensens are rated at 0-150 volts at a maximum of
12 amps while the Hewlett Packards produce 0-60 volts at a maximum of 3 amps All of
the power supplies are computer-controlled however the Sorensens may be operated
manually ifdesired Voltage measurements from the power supplies are fed into the
Keithley acquisition chassis and are then routed to the computer A voltage from the
computer is buffered and fed into the control circuits of the power supplies This voltage
completes the loop and controls the output voltage of the power supplies The software is
responsible for reading the output voltage of the power supplies comparing it with the
intended setpoint and adjusting the control voltage as needed This arrangement allows the
user to vary the output voltage of the power supplies from within a program Computershy
controlled safety relays are in place to disconnect the power supplies should they stray too
far from the intended voltage setpoint Fig D1 displays the system
77
Thermocouple and Voltage Inputs
r
Computer Data Acquisition Chasis Intaface
00 Voltage and 1 r Current
Measurement
Computer
I I
Analog Control Signal
Digital Oulput Signals 5 6
Power Supply 4 Relay Rack
Power Supply 3 00000001 Power Supply 2
Buffered Analog100000001 Power Supply 1 Control Signal
1 2 3 4 5 6 - I
I00 00 )0 po po po
Ir Digital Outputs
Analog Outputs
Fig DI Data Acquisition and Control System
78
APPENDIX E EXPERIMENTAL RAW DATA AND PLOTS
E1 Temperature Profile Plots From Fixed Thermocouples
In this appendix the remaining tests for the fixed thennocouple testing presented in Section
41 are provided Figures E1 and E2 give the results from the fresh food compartment
and Figures E3 and E4 give the results from the freezer Notice the outdoor and interior
ambient temperatures are not the same as the two tests presented in Section 41
191
Run 2 ttl ~ i i
middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot
middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot-imiddotmiddot
TWall
middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotlmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot
-
Outdoor Ambient =210 degC Fresh Food Ambient =375 degC
-] _ Door ProfUe i -il- 0 Wall Profile
i 19
$-- - Tdo = 19078 - 001326x
l~l ~~i 189 i i a m
0 i -m-
i 188 middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot
187 ~ middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot 5 = 18989 - O02024x 1
F 186
~bullbullbullbullbullbullbullmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot185 i i
184 0 5 10 15 20 25
x (mm)
Fig E1 Steel Skin Temperature Plot for Fresh Food Compartment (Run 2)
79
191
19
189
a ~
i 188
187
5F
186
185
184 0
Run 3 I --D - Door Profile
middotmiddotmiddotmiddotmiddotmiddotmiddotmiddot-middotmiddotmiddotmiddot~middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotimiddotmiddot-middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddot 0 Wall Profile
i - i - - Tdo =19053 - 001384x or
=c-=r=-~-= 1 11=
~ n - 189S 001998 --t-shy-~~-
5 10 15 20 25
x (mm)
Fig E2 Steel Skin Temperature Plot for Fresh Food Compartment
186
184
182
- ~- 18
178
~ 176
174
172 0
(Run 3)
Run 2 l --0 - Door Profile
middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot~middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotdrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotf 0 Wall Profile - 1- - middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot--m
- - T =18544 - 002398x i - i door rb
~i
i bullbullbulli _ bull imiddot
~ I TWall =18182 - 003542x tmiddotmiddotmiddotmiddot middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotlmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot
~ n~l l
5 10 15 20 25
x (mm)
Fig E3 Steel Skin Temperature Plot for Freezer (Run 2)
80
--a 0
I5F
186
184
182
18
178
176
174
172
Run 3 I --0 - Door Profile
middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotCmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotl 0 ~a1l Profile
ttl __ OJ 1 1 middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotfmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotlmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot -shy - Td = 18411 - 002272x ibullbullbullbullbullbullbull-bullbullbullbullbullbullbullbullbulli
oor ~
rp bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbull bull 11_1
I I middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotimiddotmiddotmiddotmiddot middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotImiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot
~ _l
Outdoor Ambient =208 degc Freezer Ambient = -93 degc
0 5 10 15 20 25
x (mm)
Fig E4 Steel Skin Temperature Plot for Freezer (Run 3)
E2 Thermopile Data Reduction
The data from the thennopile tests consist of an output voltage (mV) measured with a
Keithley multimeter which has a resolution of 1 m V The procedure required to translate
this voltage into a temperature difference follows
1 Read the output voltage in millivolts
2 Detennine the average skin temperature from fixed thennocouple data
3 Use the reference table and the average skin temperature to determine the conversion factor in Vrc
4 Convert to temperature difference as follows
1T = ____o_utpu_t_vo_l_tag-e___
ofjunctions x conversion factor
81
Table EI Thermopile Raw Data
ffOutput fzOutput ff Ave Skin Temp fz Ave Skin Temp mV mV CC CC
Roo wall door wall door wall door wall door
1 0052 0048 0045 0050 189 191 177 183
2 0054 0052 0046 0048 187 189 176 182
3 0056 0053 0046 0051 186 188 175 181 ff Conv Factor fz Conv Factor ff AT fzAT
Ilvrc Ilvre CC CC
Roo wall door wall door wall door wall door
1 40165 40181 40067 40116 026 024 037 041
2 40148 40165 40058 40107 027 026 038 040
3 40140 40157 40050 40099 027 026 038 040
Average Temperature Difference 0267 0377 0253 0403
from Thermocouple Reference Tables Based on the IPTS-68 US Dept of Commerce
E3 Experimental Determination of qwall and qdoor Details
The four heat fluxes are calculated using
-k M (El)q - m Ax
For 05 carbon cold rolled steel km =540 Wm K (312 Btuhr-ft-OF) Also Ax = OOlm (039 in) for all computations
0267degC 2 qwallff = 54 Wm-K 001 m = 14418 Wm
_ 0377 degc _ 2 qwallfz - 54 Wm-K 001 m - 20358 Wm
0~3~ 2 qdoorff =54 Wm-K 001 m =13662 Wm
82
0403degC 2 qdoorfz = 54 Wm-K 001 m = 21762 Wm
Compute the heat transfer rate according to Equation (B2)
q =qA=qhP (B2)
Where A is the cross sectional area of the steel casing that is perpendicular to the direction
of heat flow The area is the product of the steel skin thickness b and the total perimeter of
the compartment opening which is exposed to the room environment P Perimeter
definitions
Pwallff = llm + 076m +llm = 296 m
roJ D Pwallfz =O4lm + 076m + O4lm =l58 m
I ] I ~I Pdoorf( = llm + 076m + llm + 076m = 372 m
Pdoorfz =076m + O4lm + 076m + 041m =234 m
83
qwallff =(14418 Wm2)(65e-4 m)(296 m) =277 W
qwallfz =(20358 Wm2)(65e-4 m)(158 m) =209 W
qdoorff =(13662 Wm2)(65e-4 m)(372 m) =330 W
qdoorfz =(21762 Wm2)(65e-4 m)(234 m) =331 W
E4 Temperature Profile Plots From Mullion Data (Heater oro
The following plots are from the remaining runs for the mullion analysis presented in
Section 45 All data is taken from the exact center of the mullion
131
13 middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot-tmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotjmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotlmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot9middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotlmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot6middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddot T 11 f =12383 + 0019929x iii mu z
129 ~ middotImiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot[middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddota ~
i 128 middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot4middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot-j-middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotfmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotfmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot
127e ~
126 ~~~=H~~-~=HmiddotrI~ ++~11 Room Ambient =2250 degC125
1 1 i Fresh Ambient =515 degC iii i i Freezer Ambient =-603 degC
124
1 10
Fig ES Mullion Temperature Profile Run 2 (Heater Off)
Run 2
2 3 4 5 6 7 8 9
TIC
84
146
145
a 144 ~
i 143
5 ~ 142
141
Run 3 9 0
---r-r--deg-r-ideg-t-9--rshyiii ltD T 11 ff = 15173 - OOI71x mu bull
middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotfmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotImiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot6middotmiddot
1Tmull~fz =14062 + J0158211x JLt 1
Q 1 1 1 middotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1-middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddoti-middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotimiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotoot-middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot-I-bullbullbull~bullbullbullbullbullbullbullbullbullbullbull
iii middotiiimiddot-j Room
1Am~t = 21~1 degC
iii i 1 Fresh Ambient = 563 degC 1 1 1 1 1 Freezer Ambient = -153 degC
14~---+--~----r---+---~---+--~----r---+-
1 2 3 4 5 6 7 8 9
TIC I
Fig E6 Mullion Temperature Profile Run 3 (Heater Off)
127
126
125 a ~
i 124
123 e ~
122
121
12
1
Fig E7
i i CD middotmiddotmiddotmiddot----middotmiddot-r--middot---middotmiddotmiddotmiddotmiddotmiddot-lmiddot--------middotmiddotmiddotmiddotl-middotmiddot---middotmiddotmiddotmiddot---r---middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1middotmiddotmiddotmiddotmiddot---middotmiddot---middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot-r----middot1__ _-
I I I T mulIff = 1321 - 001532x middotmiddotmiddotmiddot------middott--------------tmiddotmiddot----middot----middotmiddot-1------middotmiddotmiddotmiddotmiddotmiddot---jmiddot-----middotmiddotmiddotmiddotmiddotmiddotmiddotmiddot-lmiddotmiddotmiddot---middotmiddotmiddot-----tmiddotmiddotmiddotmiddotmiddot--middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddot-----middotmiddotmiddot6middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot
I cent I I I I -~~~~-ro-Tr-
r-middotmiddotmiddotmiddotrTTr-middotrmiddotrmiddotrmiddot middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddott middotmiddotmiddottmiddotmiddot1middotmiddotbullbullbullbull fmiddotbullbullbullbullbullbullbullmiddot-fbullbullbullbullbullbullbullmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot
II Room Ambil =21~3 degC iii i i Fresh Ambient =551 degc iii i i Freezer Ambient = -681 degC
2 3 4 5 6 7 8 9 10
TIC I
Mullion Temperature Profile Run 4 (Heater Off)
85
10
111
iii i i 11
Fttul5
T mu
=J=~[rr~tl=rI=109
a ~ 108 -t-t-t-i~FFl~i~~
+-0amp_- -+_bullbullbullbullbullbullbullbull+ - bullbullbull 107 11 f ~ 10325 + 0021893x 1 1 1 ji
5 bull Z iii
------~-~-----~---i --L--l ---_l__ ---L-----_shy106 ~
105 -t---i--+-+-+-middot++-I-shyL1LLL Room Ambient = 2177 C104 iii i i Fresh Ambient =448 degC
Freezer Ambient = -644 degC 103
1 2 3 4 5 6 7 8 9 10
TIC
Fig E8 Mullion Temperature Profile Run 5 (Heater Off)
86
34
33 1 1 1 1 1 1 1 1------I---------middotmiddot--+middotmiddotmiddotmiddot------middottmiddot-------middotmiddotmiddotmiddottmiddot----------middotmiddotmiddot---middot---middot----tmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot---middotmiddott--middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot(middotmiddotmiddotmiddotmiddot--
32 11 f =1 2859 ~ OI~X j
Till ff =133013 j - 007124x mu
31
a ~ 30
i 5 ~
29
28
27
26
Tmullfz = 26944 + 014842x
mu t-tr l
25 middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotjmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotjmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotlmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1middot ~ u~ ~it
24 lllti1 ~ i i ~ i
0 Lower Limit
23
0 1 2 3 4 5 6 7 8 9 10
ES Temperature Profile Plots From Mullion Data (Heater On)
The following are the remaining plots from the mullion heater analysis presented in Section
46
TIC I
Fig E9 Mullion Temperature Profile Run 2 (CenterHeater On)
Run 2
T muz
1
87
l----+
29
middotmiddotmiddotgtmiddotmiddoti middot 0 upper Limit 28 Run 1
I
middotmiddotI o
Tmullfz
T muo
LL~4cb 0 Lower Limit27
middot~+ImiddotmiddotmiddotImiddotmiddotmiddottr9middotdJmiddotmiddotmiddotmiddot 26
t T = 29465 008022xmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddot1middotmiddotmiddotmiddotTmiddotmiddotmiddotmiddot[middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1middot mullffa 25~
i 24 =24837+ 013186x middotlmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot+middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotimiddotmiddotmiddotmiddotmiddotmiddotmiddotlmiddotmiddotmiddotmiddotmiddotmiddot iii i i
i _ Jbullbullbullbullbullbullbullbullbullbullbullbullbulli l _l ii 23
e 22~ 21 +I~=tt=l=fit
L~LLL Tm~llff = 23856 005858x20 11 f = 1803 + 02243x z -rmiddotmiddotmiddotmiddot1middot middotmiddot middotmiddot 1middotmiddotmiddotmiddotmiddotTmiddotmiddot middot-rmiddot19
18
0 1 2 3 4 5 6 7 8 9 10
TIC
35
34
33
32
a ~ 31
I ~
30
29
28
27
26
25
24
Fig EI0
---bull---i----bullbullmiddotmiddotmiddotmiddot--~--------middotmiddot-+------ j bullbullbullbull ---bullbullbullbull -i--__---
T 11 f =30063 + OI~x 1 T i 134 196 i
0068 1 38
muz tmiddotmiddot Ilff=middot bull x ltP lt1gt mu
=t=H=t+t=R=t= F-6~I-i~E
Tmullfz = 28103 + 014486x 1middot++middot1middot1
middotmiddotmiddot--middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotimiddotmiddotmiddotmiddotmiddotmiddotmiddot-middotmiddotmiddotmiddotmiddot+middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotbullbullmiddotmiddotmiddot-middotmiddotimiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot~middotmiddot
111111 0 Upper Limit iii iii 0 Lower Limit
0 1 2 3 4 5 6 7 8 9 10
TIC
Mullion Temperature Profile Run 3 (CenterHeater On)
Fig Ell Mullion Temperature Profile Run 1 (LeftHeater On)
88
a
29
28
27
26
25~
i 24
23 e
22~ 21
20
19
18
Fig E12
i l middot middotmiddotmiddotmiddotlmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot+ 0 Upper Limit T 11 f =24474 + 011288x i imu bull z o Lower Limit
=tplusmntplusmnfrplusmnplusmnplusmn ~ I I I I Tmull ff ~ 28793 - o0784x
middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddott----middot------middotmiddotimiddot----middot-middotmiddot--middot-~-middotmiddotmiddot--middot----middotmiddot)middot
=ii=t=1=P-Ltplusmnt iii i T = 25599 - 00689xIfmiddotTTTmiddotmiddotrmiddot ~Ullff iii
T l1f =20552 + 01676x i~~imiddotimiddotmiddot
==~LL L LLLLL i i 1 ~ 1 ~
0 1 2 3 4 5 6 7 8 9 10
TIC I
Mullion Temperature Profile Run 2 (LeftlHeater On)
33 iii i i
-middot--middot(---middotmiddot--middotmiddot--middotmiddot+---middot-middotmiddotmiddotmiddot-middotmiddotmiddot~-middot--middot-------middoti---middot------~ o Upper Limit 32 Run 3
t bullbullbull +
Tm~llfz
T mu
1 1 1 1 1 o Lower Limit ~~31
=2713 ~ 0113~x j11Li30
a T ulff =30658 - 006506x 29~
IktlJ2~Li 28
27 e
26 =l=tt=tmiddotmiddottmiddott+~middot+=t=~ middotmiddot jmiddotjmiddottmiddottmiddotjmiddot T = 28288 - 00603x
iii i mullff 24
25
middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotQmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot+middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot~middotmiddotmiddot middotmiddotmiddotmiddotmiddotmiddotmiddotmiddot~middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot+middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot 11 fz = 2377 ~ 01788x IL11123 i i
22
0 1 2 3 4 5 6 7 8 9 10
TIC I
Fig E13 Mullion Temperature Profile Run 3 (LeftHeater On)
89
31
30
29
ltP ~u
J
1 T
-~Lti=t~-t--t i~+--Ij Tmu1lff =31473 middot005222x 28
1 1 1middot 1 l i l i bullbullbullbullbullbullbull__ bullbullbullbull_ bullbullbullbullbullbullbull~_bullbullbullbullbullbullbullbullbulla bullbullbullbullbullbullbullbullbullbullbull a 27
~ Tm~llfz = 26857 + 01734x _~__+_+II i
26
bullmiddotmiddotbullbullbullmiddotmiddotbullibullbullbullbullbullbullbullbullbullbullbullmiddotmiddotmiddotbullbullbullbullbullbullbullbullmiddotmiddotmiddotmiddot bullbullbullbullbullbullbullbullbull-i-~-i-ii25
JJ$~L-f$9 5 24
~ 23 middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotlmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot+middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot~middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot+middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1-middotmiddot T mllff =25622 bull 002~7X c-bullbullbullbullbullbullbullbullbullbullbullbull+ ~~ 22 rp 1 1 i i 1 1 1
21 = 19464 + 02548 jmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddott Upper Limitmullfz xii 0
4-bullbullbullbullbullbullbullbullbullbullbullbullimiddotmiddotmiddotbullbullbullbullbullbullmiddotf20 i 1 ~ 1
19
0 1 2 3 4 5 6 7 8 9 10
TIC I
Fig E14 Mullion Temperature Profile Run I (RightHeater On)
33 i
middotmiddotmiddotmiddotlaquomiddotmiddotmiddotmiddot------------------------------- c--------middotmiddotmiddot-middot-----------middotmiddotmiddot---middotmiddot--------l-----middot-----I-----32
= 2757 + 017006x ILLJ1
a
31
30
29~
i 28
Run2
TmulIfz
T~ulIfz ~
-~t=ii~Ii~~~~ i
27 middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot9-middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotT~~middotmiddotmiddotmiddotmiddot2s944-middot~middotmiddotO0278~middotmiddote 26~ r~rrTt+rr25
24 2320~ + O~S4x middotmiddotlmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotjmiddot ~ u~ L~t 23 middotmiddotmiddotmiddotmiddotmiddotmiddotmiddot~middotmiddotmiddotmiddotmiddotmiddotmiddot+middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot+middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot+middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotImiddotmiddotj 0 Lower Limit
22
0 1 2 3 4 5 6 7 8 9 10
TIC I
Fig EIS Mullion Temperature Profile Run 2 (RightlHeater On)
90
33 i i ~ _______ _ _~____ __ __-i--bullbullbullbullbullbullbullbull-t------ -- uu__~ ~ --~32
=1268931+ 0~4~14X 111131
30
a 29~
I 28
Run3
Tmullfz
i t+ I T
m
mnplusmn~~27 6 i 1 i 1 +++ T mullff =28912 - 002938x 26~ +middotmiddot++Imiddotjmiddott-25
= 22996 + 02312x 1middotmiddot+ 24
~~~~L lL1 0 ~23 ill 0 22
0 1 2 3 4 5 6 7 8 9 10
TIC
Fig E16 Mullion Temperature Profile Run 3 (RightHeater On)
91
APPENDIX F NUMERICAL SIMULATION EQUATIONS AND CODE
F1 Finite-Difference Equations
Figure Fl is a generic resistor network that is used as a base for all the finite-difference
equations The general fonn is
(Fl)
r----II ij+l
J
i j-l L ______--J
Fig F1 Generic Nodal Resistor Network
This makes it easy to simply plug in the different resistors for the different regions of the
section There are twelve resistors total The following table summarizes the resistors
needed to complete the model
Table F1 Model Resistors
Description Resistance [CIW]
Interior insulation x direction Rl= dx dymiddotkinsmiddotb
92
dyInterior insulation y direction R2= dx-kins-b
dySteel parallel with insulation y direction R3= km-dm-b + kins-(dx -dm)
dxR=Steel parallel with insulation x direction km-dm-b + kins-(dy -dm)
dyRs=Plastic parallel with insulation y direction
kp-dp-b + kins-(dx -dp)
dxPlastic parallel with insulation x direction R6= kp-dp-b + kins-(dy -dp)
heffa- (~- dm) + kinsSteel to exterior x direction R7= 2
heffo-kins-dy-b
heffa- (dY - dm) + kinsSteel to exterior y direction R - 28shyheffo-kins-dx-b
hefti- (dY _dm) + kinsSteel to interior y direction R9= 2
heffi-kins-dx-b
hefti- (~- dp) + kinsPlastic to interior x direction RIO= 2
heffi-kins-dy-b
Rll = hefti- (dJ -dP) + kinsPlastic to interior y direction
heffi-kins-dx-b
93
Steel skinplastic skin interface
2middotkmmiddotdmmiddotkpmiddotdpmiddotdxR12=----------------------~~----------------
2middotkmmiddotdmmiddotkpmiddotdpmiddotbmiddot(dy -dp) + (kpmiddotdp + kmmiddotdm)middotbmiddotdx2
F2 Wall Simulation Source Code
Program FiniteDiff
c This program simulates the conductive heat transfer through the wall section c of the refrigerator near the door gasket using Guass-Siedel iteration c The program allows for flexibility in the geometry and material properties c The program is a steady-state model
cVariable Definitions
c km = conductivity of the outer metal skin (Wm-K) c kins = conductivity of the polyurethane foam insulation (Wm-K) c kp conductivity of the inner plastic skin (Wm-K) c dm = thickness of the metal skin (mm) c dp = thickness of the plastic skin (mm) c b = depth of the section (m) c heffo = effective heat transfer coefficient on outside surfaces (Wm2-K) c heffi = effective heat transfer coefficient on inside surfaces (Wm2-K) c sl width of wall inSUlation (mm) c s2 length of wall section (mm) c s3 seal indentation (mm) c s4 seal width (mm) c s5 distance metal skin travels into cabinet (mm) c s6 distance platic skin travels out of cabinet (mm) c ns = number of nodes corresponding to the s regions above c rs = network resistors (m-eW) c i = integer values of distance along the x axis c j = integer values of distance along the y axis c imax maximum integer value in x direction c jmax maximum integer value in y direction c iter total number of iterations to converge c loop convergence flag c Qinl Heat flux per unit length across the outer boundary (Wm) c Qin2 Heat flux per unit length across the inner boundary (Wm) c Qdif Qinl - Qin2 (Wm) c Qpdif = percent difference between the heat fluxes Qinl and Qin2 c Ti Inside ambient temperature (e) c To = Outside ambient temperature (e)
cDeclare Variables
INTEGER nln2n3n4n5n6ijloopimaxjmaxiter INTEGER clflaglflag2 REAL kmkinskpdmdpdxdyheffoheffi REAL TiToQdifQpdifQinlQin2 REAL sls2s3s4s5s6lenoutlenin REAL rlr2r3r4r5r6r7r8r9rlOrllr12 REAL T(-1lOl-1lOl)bqlDsumlsum2 REAL Qm(lOl)qfluxm(lOl)fluxo(OlOl)fluxi(OlOl)
94
REAL fluxcen(0101)pfluxcen(0101)pfluxo(0101) REAL pfluxi(0101)pmaxdifoneDtolaq2Dqedge1
OPEN (10file-2Dcode(v11)out1position-rewind) OPEN (11file-2Dcode(v11)out2position=rewind)
cTest Parameters
c thermal conductivity of the outer metal skin (Wm K) km-540
c thermal conductivity of the wall insulation (Wm K) kins=0021
c thermal conductivity of the inner plastic skin (Wm K) kp=015
c thickness of the metal skin (mm) dm=065
c thickness of the plastic skin (mm) dp=25
c effective heat transfer coefficient on outside surfaces (Wm2-K) heffo=681
c effective heat transfer coefficient on inside surfaces (Wm2-K) heffi=610
c width of section (mm) sl=450
c length of section (mm) s2=2000
c depth of the section (m) b=10
c inside ambient temperature (C) Ti=95
c outside ambient temperature (C) To=210
c unit conversions dm=dm1000 dp=dp1000 sl=sl1000 s2=s21000
c specify 1-dimensional tolerance (t) oneDtol=30
cMesh Parameters
c specify the following nodal mesh parameters n1=20 n2=80 n3=1 n4=9 n5=10
c various mesh dimensions dx=sln1 dy=s2n2 s3=n3dx s4=n4dx s5=n5dx s6=sl-s5-dx n6=s6dx imax=n1-1 jmax=n2-1
cInitialize temperature matrix
DO 10 j=-1jmax+1 DO 20 i=-1imax+1 T(ij)=Ti
95
20 CONTINUE 10 CONTINUE
DO 30 j=Ojmax T(-Ij)=To
30 CONTINUE
DO 40 i=0n3 T(i-I)=To
40 CONTINUE
DO 50 j=Ojmax T(imax+lj)=Ti
50 CONTINUE
DO 60 i=n3+n4+1imax T(i-I)=Ti
60 CONTINUE
cResistors [m-CW]
c interior insulation x direction rl=dx(kinsdy)
c interior insulation y direction r2=dy(kinsdx)
c metalinsulation y direction r3=dy(kmdm+kins(dx-dm))
c metalinsulation x direction r4=dx(kmdm+kins(dy-dm))
c plasticinsulation y direction r5=dy(kpdp+kins(dx-dp))
c plasticinsulation x direction r6s dx(kpdp+kins(dy-dp))
c metal to exterior x direction r7=(heffolaquodx2)-dm)+kins)(heffokinsdy)
c metal to exterior y direction rB=(heffo laquody2)-dm) +kins)(heffokinsdx)
c metal to interior y direction r9=(heffilaquody2)-dm)+kins)(heffikinsdx)
c plastic to interior x direction rl0=(heffilaquodx2)-dp)+kins)(heffikinsdy)
c plastic to interior y direction rll=(heffilaquody2)-dp)+kins)(heffikinsdx)
c metalplastic interface rI2=(2kmdmkpdpdx)(2kmdmkpdp(dy-dp) + (kpdp+km dm)dxdx)
cxxxxxGuass-Siedel Iterationxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx loop=1 iter=1 DO WHILE (loop eq 1)
c Equations for row 0 i=O j=O CALL sseqn(Tr4r7r3rBijimaxjmax)
DO 70 i=ln3 j=O CALL sseqn(Tr4r4r2rBijimaxjmax)
70 CONTINUE
DO 75 i=n3+1n5-1
96
j=O IF (i le n3+n4) THEN
CALL sseqn(Tr4r4r21e20ijimaxjmax) ELSE
CALL sseqn(Tr4r4r2r9ijimaxjmax) ENDIF
75 CONTINUE
i=n5 j-O IF (i le n3+n4) THEN
CALL sseqn(Tr12r4r21e20ijimaxjmax) ELSE
CALL sseqn(Tr12r4r2r9ijimaxjmax) ENDIF
i=n5+1 j=O IF (i le n3+n4) THEN
CALL sseqn(Tr6r12r21e20ijimaxjmax) ELSE
CALL sseqn(Tr6r12r2rllijimaxjmax) ENDIF
DO 80 i=n5+2imax-l j=O IF (i le n3+n4) then
CALL sseqn(Tr6r6r21Oe20ijimaxjmax) ELSE
CALL sseqn(Tr6r6r2rllijimaxjmax) ENDIF
80 CONTINUE
i=imax j=O CALL sseqn(TrlOr6r5rllijimaxjmax)
c Equations for rows 1 thru jmax-l DO 90 j=ljmax-l
i=O CALL sseqn(Tr1r7r3r3ijimaxjmax)
DO 100 i=1imax-1 CALL sseqn(Tr1r1r2r2ijimaxjmax)
100 CONTINUE
i=imax CALL sseqn(Tr10r1r5r5ijimaxjmax)
90 CONTINUE
c Equations for row jmax j=jmax i=O CALL sseqn(Tr1r710e20r3ijimaxjmax)
DO 110 i=1imax-1 j=jmax CALL sseqn(Tr1r110e20r2ijimaxjmax)
110 CONTINUE
i=imax j=jmax CALL sseqn(Tr10r11Oe20r2ijimaxjmax)
97
c c c
Compute the difference in heat flux crossing the outer boundary and crossing the inner boundaryr ideally the difference should be zero
CALL balance(TToTidxdyn3n4imaxjmaxQdifQpdif c QinlQin2r7r9r8rlOrllb)
c Update loop variables iter-iter+l
c Convergence criterium IF (Qpdif le 20) then
loop-O ENDIF IF (iter eq 10000) THEN loop=O write(lO) Solution did not converge
ENDIF
END DO cxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
cHeat Transfer Calculations
c Compute 10 heat flux through wall CALL oneD (ToTiheffoheffikmkinskpdmdpslqlD)
c Compute the flux thru wall at each node on the c outside and inside walls [Wm2) Also the flux c in the x-direction across the center line of the c section
cl-int(nl2) fluxcen(0)=(1(r4dy))(T(cl0)-T(cl+l0)) fluxo(0)=(1(r7dy))(To-T(00)) fluxi(O)=(l(rlOdy))(T(imaxO)-Ti) DO 112 j=ljmax
fluxcen(j)=(l(rldy))(T(clj)-T(cl+lj)) fluxo(j)=(1(r7dy))(To-T(0j)) flumiddotxi (j) =(1 (rlOdy)) (T (imax j)-Ti)
112 CONTINUE
c Determine the percent of steady-state 10 losses DO 113 j=Ojmax
pfluxcen(j)=(fluxcen(j)qlD) 100 pfluxo(j)=(fluxo(j)qlD)lOO pfluxi(j)=(fluxi(j)qlD)lOO
113 CONTINUE
c Determine where the heat transfer becomes 10 c based on a criticle percentage
flagl=O DO 114 j=O jmax
a=abs(pfluxcen(j)-lOOO) IF (j ne jmax) THEN
IF (a le oneDtol) THEN jstar=j
ENDIF ELSE
IF (a le oneDtol) THEN jstar=j
ELSE flagl=l
ENDIF ENDIF
98
114 CONTINUE
c Determine the edge loss by subtracting the 10 heat c transfer from the heat transfer in the 20 region c across the centerline
flag2=0 IF (flagl eq 0) THEN
q2D=00 DO 115 j=O jstar
q2D-q2D+fluxcen(j) 115 CONTINUE
qedgel=q2D-qlD ELSE
flag2=1 ENDIF
c 10 heat flux along metal skin under the seal into c the cabinet [Wm2J Fluxes for all metal nodes are c computed as well as an average flux The flux from c node (n3+l0) to node (n3+20) is given as qlDm(l) c and so on Assume the temperature of the metal skin c is the temperature of the node at that location
suml=OO sum2=00 DO 119 i=n3+1n3+n4-l
Qm(i)=laquokmdmb)dx)(T(i0)-T(i+10raquo qfluxm(i)=(kmdx)(T(iO)-T(i+lOraquo suml=suml+Qm(i) sum2=sum2+qfluxm(i)
119 CONTINUE pmaxdif=laquoQm(n3+n4-l)-Qm(n3+1raquoQm(n3+lraquo100 qedge2-qfluxm(cl)
cOutput
c Output nodal temperatures to separate file DO 120 j=Ojmax
write(ll) (T(ij)i=Oimax) 120 CONTINUE
c Output flux info to a different file write(10) INPUT PARAMETERS write(lO) write (10 ) Section Dimensions (mm) write(lO) Width sl1000 write (10 ) Length s21000 write(10) Depth blOOO write(10) Steel skin thickness dmlOOO write(lO) Plastic skin thickness dplOOO write(lO) write(10) Mesh Geometry write(10) dx dxlOOO write(lO) dy dylOOO write(lO) Number nodes in x-direction n1 write(lO) Number nodes in y-direction n2 write(lO) Number of steel skin nodes write(lO) (including corner 00) n5+l write(10) Steel nodes under the seal n3+1 ton3+n4 write(10) write(lO) Steel skin conductivity (Wm K) km write(lO) Foam insulation conductivity (Wm K) kins write(lO) Plastic skin conductivity (Wm K) kp write(lO) Outside h (Wm2 K) heffo write(lO) Inside h (Wm2 K) heffi
99
write(10) Outside Temp (C) To write(10) Inside Temp (C) Ti write(10) write (10 ) write(10) write(10) OUPUT PARAMETERS write (10 ) write(10) Number of iterations iter write(10) write(10) Heat Transfer for the Section write(10) OVerall Heat Transfer (W) Qin1 write(10) 10 Heat Flux Thru Wall (Wm2) q1D write (10 ) write(10) Heat Transfer Along Metal Skin Under Seal write(10) node to node qm[Wm2J Qm[WJ DO 135 i=n3+1n3+n4-1
write(10) i i+1 qfluxm(i) Qm(i) 135 CONTINUE
write (10 ) Maximum difference () abs (pmaxdif) write(10) IF (flag2 eq 1) THEN
write(10) The mesh does not extend far enough write(10) in the y-direction to reach 10 heat write(10) transfer for the specified tolerance write(10) ofoneDtol
ELSE write (10 ) Edge loss computed from qe=q2D-q1D qedge1 write (10 ) write(10) Edge loss computed directly from write(10) steel skin ~T at centerline qedge2
ENDIF write (10 ) write (10 ) write(10) Heat fluxes in thru the section write(10) along the centerline [Wm2J write (10 ) write(10) j flux 10 DO 136 j=Ojmax
write(10) j fluxcen(j) pfluxcen(j) 136 CONTINUE
PAUSE STOP END
C
SUBROUTINE sseqn (Trplusirminusirplusjrminusj i jimax jmax)
c This subroutine computes the temperature at node (ij) c given the temperatures of the surrounding nodes and c the resistances leading to these nodes
INTEGER ijimaxjmax REAL T(-1101-1101)rplusirminusirplusjrminusj REAL c1c2c3c4c5
c1=1rplusi c2=1rminusi c3=1rplusj c4=1rminusj c5=c1+c2+c3+c4
T(ij)=(1c5)(c1T(i+1j)+c2T(i-1j)+c3T(ij+1)+c4T(ij-1raquo
100
RETURN END
C
SUBROUTINE balance(TToTidxdyn3n4imaxjmaxQdifQpdif c Qin1Qin2r7r8r9r10r11b)
c This subroutine computes the steady-state heat balance c for the cross-section
INTEGER imaxjmaxijn3n4 REAL T(-1101-1101)TlToQin1Qin2dydx REAL r7r8r9r10r11b
c Compute the heat entering Qin1 [Wj Qin1=00 DO 10 jOjmax
Qin1=Qin1+(b(r7))(To-T(0j)) 10 CONTINUE
DO 20 i=0n3 Qin1=Qin1+(b(r8))(To-T(i0))
20 CONTINUE
c Compute the heat leaving Qin2 [Wj Qin2=00 DO 30 j=Ojmax
Qin2=Qin2+(b(r10))(T(imaxj)-Ti) 30 CONTINUE
DO 40 i=n3+n4+1imax IF (i le nS) then
Qin2=Qin2+(b(r9))(T(i0)-Ti) ELSE
Qin2=Qin2+(b(r11))(T(i0)-Ti) ENDIF
40 CONTINUE
c Compute the absolute difference in heat fluxes [Wj Qdif=abs(Qin2-Qin1)
c Compute the percent difference in the heat transfers [Wj Qpdif=(QdifQin1) 100
RETURN END
C
SUBROUTINE oneD (ToTiheffoheffikmkinskpdmdpslqlD)
c This subroutine compute the one-dimensional c heat flux through the section wall
INTEGER i REAL ToTiheffoheffikmkinskpdmdpsl REAL q1DReqdins
dins=sl-dm~dp
Req=(lheffo) + (dmkm) + (dinskins) +(dpkp)+(lheffi) q1D=(To-Ti)Req
RETURN END
101
F3 Fresh Food Wan Simulation Output
INPUT PARAMETERS
Section Dimensions (mm) Width 4500 Length 2000 Depth 1000 Steel skin thickness 6500 Plastic skin thickness 2500
Mesh Geometry dx 2250 dy 2500 Number nodes in x-direction 20 Number nodes in y-direction 80 Number of steel skin nodes (including corner 00) 11 Steel nodes under the seal 2 to 10
Steel skin conductivity (Wm K) 5400 Foam insulation conductivity (Wm K) 21000E-02 Plastic skin conductivity (Wm K) 1500 Outside h (Wm2 K) 6810 Inside h (Wm2 K) 6100 Outside Temp (C) 2100 Inside Temp (C) 4000
OUPUT PARAMETERS
Number of iterations 5318
10 Heat Flux Thru Wall (Wm2) 9132
Heat Transfer Along Metal Skin Under Seal node to node qm[Wm2] Qm[W]
2 3 1619 1092 3 4 1612 1081 4 5 1660 1019 5 6 1645 1010 6 1 1626 1051 1 8 1601 1041 8 9 1569 1020 9 10 1521 9922
Maximum difference () 9101
Edge loss computed directly from steel skin 1T at centerline 1645
Heat fluxes in thru the section along the centerline [Wm2]
j flux 10 0 4284 4691 1 2246 2459 2 3513 3841 3 4554 4981 4 5311 5881 5 6001 6512 6 6488 1104 1 6868 1520
102
10
20
30
40
50
60
70
8 7169 7850 9 7412 8117
7612 8335 11 7778 8517 12 7918 8670 13 8037 8800 14 8139 8912 15 8227 9008 16 8303 9092 17 8369 9164 18 8428 9228 19 8479 9285
8525 9334 21 8565 9379 22 8601 9418 23 8634 9454 24 8663 9486 25 8690 9515 26 8714 9542 27 8736 9566 28 8756 9588 29 8775 9609
8793 9628 31 8809 9645 32 8824 9662 33 8838 9677 34 8851 9692 35 8863 9705 36 8875 9718 37 8886 9730 38 8896 9742 39 8906 9752
8916 9763 41 8925 9772 42 8933 9782 43 8941 9791 44 8949 9799 45 8956 9807 46 8963 9815 47 8970 9822 48 8976 9829 49 8982 9836
8988 9842 51 8994 9848 52 8999 9854 53 9004 9859 54 9009 9864 55 9013 9869 56 9017 9874 57 9021 9878 58 9025 9883 59 9029 9887
9032 9890 61 9036 9894 62 9039 9897 63 9042 9901 64 9044 9903 65 9047 9906 66 9049 9909 67 9051 9911 68 9053 9913 69 9055 9915
9057 9917 71 9058 9919
103
72 9059 9920 73 9061 9921 74 9062 9922 75 9062 9923 76 9063 9924 77 9063 9924 78 9064 9925 79 9064 9925
j local Qwall [Wl
-1 3215 0 -45410E-02 1 -50708E-02 2 -40940E-02 3 -33836E-02 4 -27620E-02 5 -23180E-02 6 -1 9628E-02 7 -1 6076E-02 8 -1 4300E-02 9 -12524E-02 10 -10748E-02 11 -98601E-03 12 -89722E-03 13 -80842E-03 14 -71962E-03 15 -63081E-03 16 -63082E-03 17 -54202E-03 18 -54202E-03 19 -45322E-03 20 -45322E-03 21 -45322E-03 22 -45321E-03 23 -36442E-03 24 -36442E-03 25 -36442E-03 26 -27562E-03 27 -27561E-03 28 -27561E-03 29 -27561E-03 30 -27561E-03 31 -18682E-03 32 -18682E-03 33 -27561E-03 34 -18682E-03 35 -18682E-03 36 -18681E-03 37 -18682E-03 38 -98018E-04 39 -98018E-04 40 -98018E-04 41 -98018E-04 42 -98018E-04 43 -98018E-04 44 -98018E-04 45 -98018E-04 46 -98018E-04 47 -18682E-03 48 -98018E-04 49 -98018E-04 50 -98018E-04 51 -98018E-04 52 -98018E-04
104
53 -98018E-04 54 -92160E-05 55 -98018E-04 56 -98018E-04 57 -98018E-04 58 -98018E-04 59 -98018E-04 60 -92160E-05 61 -98018E-04 62 -92160E-05 63 -98018E-04 64 -98018E-04 65 -92160E-05 66 -98018E-04 67 -98018E-04 68 -92245E-05 69 -92245E-05 70 -98018E-04 71 -98018E-04 72 -98018E-04 73 -92160E-05 74 -92160E-05 75 -92160E-05 76 -92160E-05 77 -92160E-05 78 -92160E-05 79 -92160E-05
Qwallff [Wm21 = 1442 Qwallff [WI = 2775
Fresh Food Nodal Temperatures
x(mm) v(mm) 1125 3375 5625 7875 10125 12375 14625 16875 19125 21375
125 1761 1755 1748 1741 1734 1727 172 1713 1706 17 375 1768 1753 1738 1723 1707 169 1671 165 1624 1589 625 1775 1752 173 1706 1682 1656 1626 1593 1552 15 875 1781 1751 1722 1691 1659 1625 1587 1544 1494 1434
1125 -1787 1751 1715 1678 1639 1598 1553 1504 1448 1384 1375 1792 1751 1709 1667 1622 1576 1526 1471 1412 1346 1625 1798 1752 1705 1658 1609 1557 1503 1446 1384 ll17 1875 1803 1753 1702 165 1597 1543 1485 1425 1362 1294 2125 1808 1754 17 1645 1589 1531 1471 1409 1344 1276 2375 1813 1756 1699 1641 1582 1522 146 1396 133 1262 2625 1817 1758 1698 1638 1577 1515 1451 1386 132 1251 2875 1822 176 1698 1636 1573 151 1445 1379 1311 1242 3125 1826 1762 1699 1635 1571 1506 144 1373 1304 1235 3375 183 1765 17 1635 1569 1503 1436 1368 1299 1229 3625 1834 1768 1701 1635 1568 1501 1433 1364 1295 1225 3875 1837 177 1703 1635 1568 15 1431 1362 1292 1222 4125 1841 1773 1705 1636 1568 1499 143 136 129 1219 4375 1845 1776 1707 1638 1568 1499 1429 1359 1289 1218 4625 1848 1778 1709 1639 1569 1499 1429 1358 1288 1216 4875 1851 1781 1711 164 157 15 1429 1358 1287 1216 5125 1854 1784 1713 1642 1571 15 1429 1358 1287 1215 5375 1857 1786 1715 1644 1573 1501 143 1358 1287 1215 5625 186 1789 1717 1646 1574 1502 1431 1359 1287 1215
105
5875 1863 1791 1719 1647 1576 1504 1432 136 1288 1215 6125 1866 1794 1721 1649 1577 1505 1433 136 1288 1216 6375 1868 1796 1723 1651 1579 1506 1434 1361 1289 1216 6625 1871 1798 1725 1653 158 1508 1435 1362 129 1217 6875 1873 18 1727 1655 1582 1509 1436 1363 1291 1218 7125 1876 1803 1729 1656 1583 151 1437 1364 1291 1218 7375 1878 1805 1731 1658 1585 1512 1439 1366 1292 1219 7625 188 1807 1733 166 1587 1513 144 1367 1293 122 7875 1882 1809 1735 1661 1588 1515 1441 1368 1294 1221 8125 1884 181 1737 1663 159 1516 1442 1369 1295 1222 8375 1886 1812 1738 1665 1591 1517 1444 137 1296 1223 8625 1888 1814 174 1666 1592 1519 1445 1371 1297 1224 8875 189 1816 1742 1668 1594 152 1446 1372 1298 1225 9125 1892 1817 1743 1669 1595 1521 1447 1373 1299 1225 9375 1893 1819 1745 1671 1596 1522 1448 1374 13 1226 9625 1895 182 1746 1672 1598 1524 1449 1375 1301 1227 9875 1896 1822 1748 1673 1599 1525 145 1376 1302 1228 10125 1898 1823 1749 1674 16 1526 1451 1377 1303 1229 10375 1899 1825 175 1676 1601 1527 1452 1378 1304 123 10625 1901 1826 1751 1677 1602 1528 1453 1379 1305 123 10875 1902 1827 1753 1678 1603 1529 1454 138 1305 1231 11125 1903 1828 1754 1679 1604 153 1455 1381 1306 1232 11375 1904 183 1755 168 1605 1531 1456 1381 1307 1232 11625 1906 1831 1756 1681 1606 1532 1457 1382 1308 1233 11875 1907 1832 1757 1682 1607 1532 1458 1383 1308 1234 12125 1908 1833 1758 1683 1608 1533 1458 1384 1309 1234 12375 1909 1834 1759 1684 1609 1534 1459 1384 131 1235 12625 191 1835 176 1685 161 1535 146 1385 131 1235 12875 1911 1836 1761 1686 1611 1536 1461 1386 1311 1236 13125 1912 1837 1761 1686 1611 1536 1461 1386 1311 1236 13375 1913 1837 1762 1687 1612 1537 1462 1387 1312 1237 13625 1913 1838 1763 1688 1613 1538 1462 1387 1312 1237 13875 1914 1839 1764 1688 1613 1538 1463 1388 1313 1238 14125 1915 184 1764 1689 1614 1539 1464 1388 1313 1238 14375 1916 184 1765 169 1614 1539 1464 1389 1314 1239 14625 1916 1841 1766 169 1615 154 1465 1389 1314 1239 14875 1917 1842 1766 1691 1616 154 1465 139 1315 1239 15125 1918 1842 1767 1691 1616 1541 1465 139 1315 124 15375 1918 1843 1767 1692 1616 1541 1466 1391 1315 124 15625 1919 1843 1768 1692 1617 1542 1466 1391 1316 124 15875 1919 1844 1768 1693 1617 1542 1467 1391 1316 1241 16125 192 1844 1769 1693 1618 1542 1467 1392 1316 1241 16375 192 1844 1769 1694 1618 1543 1467 1392 1317 1241 16625 192 1845 1769 1694 1618 1543 1468 1392 1317 1241 16875 1921 1845 177 1694 1619 1543 1468 1392 1317 1242 17125 1921 1846 177 1694 1619 1544 1468 1393 1317 1242 17375 1921 1846 177 1695 1619 1544 1468 1393 1317 1242 17625 1922 1846 1771 1695 1619 1544 1469 1393 1318 1242 17875 1922 1846 1771 1695 162 1544 1469 1393 1318 1242 18125 1922 1847 1771 1695 162 1544 1469 1393 1318 1243 18375 1922 1847 1771 1696 162 1545 1469 1394 1318 1243 18625 1923 1847 1771 1696 162 1545 1469 1394 1318 1243 18875 1923 1847 1771 1696 162 1545 1469 1394 1318 1243 19125 1923 1847 1772 1696 162 1545 1469 1394 1318 1243 19375 1923 1847 1772 1696 162 1545 1469 1394 1318 1243 19625 1923 1847 1772 1696 1621 1545 1469 1394 1318 1243 19875 1923 1847 1772 1696 1621 1545 1469 1394 1318 1243
106
x(mm) y(mm) 23625 25875 28125 30375 32625 34875 37125 39375 41625 43875
125 1694 1662 1287 1033 8577 7336 6444 5795 5324 4995 375 1536 144 125 1068 9163 7946 6974 6189 5532 4944 625 1431 1334 1203 1066 9379 8252 7275 6423 5657 4935 875 136 127 1164 1051 9408 8374 7423 6548 573 4941
1125 131 1226 1132 1034 9353 8394 7477 6605 5766 4948 1375 1273 1193 1107 1017 9262 836 7478 6618 5779 4952 1625 1245 1168 1086 1002 9162 8302 7449 6607 5776 4951 1875 1223 1148 1069 9886 9064 8236 7408 6583 5764 4948 2125 1205 1132 1055 977 8974 8169 7362 6554 5747 4941 2375 1191 1119 1044 9671 8893 8107 7316 6522 5728 4933 2625 118 1108 1034 9588 8824 8051 7273 6492 5709 4925 2875 1172 11 1026 9518 8764 8002 7235 6464 5691 4916 3125 1164 1093 102 946 8713 796 7201 6439 5674 4908 3375 1159 1087 1015 9412 8671 7924 7172 6417 566 49 3625 1154 1083 101 9373 8636 7894 7148 6399 5647 4894 3875 1151 1079 1007 9341 8608 7869 7128 6383 5636 4888 4125 1148 1077 1004 9316 8585 7849 7111 637 5627 4883 4375 1146 1074 1002 9296 8566 7833 7097 6359 5619 4879 4625 1145 1073 1001 9281 8552 7821 7087 6351 5613 4875 4875 1144 1072 9995 927 8541 7811 7078 6344 5609 4872 5125 1143 1071 9987 9261 8533 7803 7072 6339 5605 487 5375 1143 1071 9982 9256 8528 7798 7067 6335 5602 4868 5625 1143 107 9979 9253 8524 7795 7064 6332 56 4867 5875 1143 107 9978 9251 8522 7793 7062 6331 5599 4866 6125 1143 1071 9979 9251 8522 7792 7061 633 5598 4866 6375 1144 1071 9981 9252 8523 7792 7061 633 5598 4865 6625 1144 1071 9984 9255 8524 7793 7062 633 5598 4865 6875 1145 1072 9988 9258 8526 7795 7063 6331 5598 4865 7125 1145 1072 9993 9261 8529 7797 7065 6332 5599 4866 7375 1146 1073 9998 9265 8533 78 7067 6333 56 4866 7625 1147 1074 10 927 8536 7803 7069 6335 5601 4867 7875 1148 1074 1001 9275 854 7806 7072 6337 5602 4867 8125 1148 1075 1001 928 8545 7809 7074 6339 5603 4868 8375 1149 1076 1002 9285 8549 7813 7077 6341 5605 4869 8625 115 1076 1003 929 8553 7817 708 6343 5606 4869 8875 1151 1077 1003 9295 8558 782 7083 6345 5608 487 9125 1152 1078 1004 93 8562 7824 7086 6347 5609 4871 9375 1152 1078 1004 9306 8567 7828 7089 635 5611 4872 9625 1153 1079 1005 9311 8571 7831 7092 6352 5612 4873 9875 1154 108 1006 9316 8575 7835 7094 6354 5614 4873 10125 1155 108 1006 9321 858 7838 7097 6356 5615 4874 10375 1155 1081 1007 9326 8584 7842 71 6358 5617 4875 10625 1156 1082 1007 933 8588 7845 7103 636 5618 4876 10875 1157 1082 1008 9335 8592 7848 7105 6362 5619 4876 11125 1157 1083 1008 9339 8596 7852 7108 6364 5621 4877 11375 1158 1083 1009 9344 8599 7855 711 6366 5622 4878 11625 1158 1084 1009 9348 8603 7858 7113 6368 5623 4879 11875 1159 1084 101 9352 8606 7861 7115 637 5625 4middot879 12125 116 1085 101 9356 861 7864 7117 6372 5626 488 12375 116 1085 1011 936 8613 7866 712 6373 5627 488 12625 1161 1086 1011 9363 8616 7869 7122 6375 5628 4881 12875 1161 1086 1011 9367 8619 7871 7124 6376 5629 4882 13125 1162 1087 1012 937 8622 7874 7126 6378 563 4882 13375 1162 1087 1012 9373 8625 7876 7128 6379 5631 4883 13625 1162 1087 1013 9376 8627 7878 7129 6381 5632 4883
107
13875 1163 1088 1013 9379 863 788 7131 6382 5633 4884 14125 1163 1088 1013 9382 8632 7882 7133 6383 5634 4884 14375 1164 1089 1013 9384 8634 7884 7134 6384 5634 4885 14625 1164 1089 1014 9387 8636 7886 7136 6385 5635 4885 14875 1164 1089 1014 9389 8638 7888 7137 6386 5636 4885 15125 1165 1089 1014 9392 864 7889 7138 6387 5637 4886 15375 1165 109 1015 9394 8642 7891 714 6388 5637 4886 15625 1165 109 1015 9396 8644 7892 7141 6389 5638 4886 15875 1165 109 1015 9398 8646 7894 7142 639 5638 4887 16125 1166 109 1015 9399 8647 7895 7143 6391 5639 4887 16375 1166 1091 1015 9401 8649 7896 7144 6392 5639 4887 16625 1166 1091 1016 9403 865 7897 7145 6392 564 4888 16875 1166 1091 1016 9404 8651 7898 7146 6393 564 4888 17125 1167 1091 1016 9405 8652 7899 7146 6394 5641 4888 17375 1167 1091 1016 9406 8653 79 7147 6394 5641 4888 17625 1167 1091 1016 9407 8654 7901 7148 6395 5641 4888 17875 1167 1092 1016 9408 8655 7902 7148 6395 5642 4889 18125 1167 1092 1016 9409 8656 7902 7149 6395 5642 4889 18375 1167 1092 1016 941 8656 7903 7149 6396 5642 4889 18625 1167 1092 1016 9411 8657 7903 715 6396 5642 4889 18875 1167 1092 1017 9411 8657 7904 715 6396 5643 4889 19125 1167 1092 1017 9412 8658 7904 715 6396 5643 4889 19375 1167 1092 1017 9412 8658 7904 715 6397 5643 4889 19625 1167 1092 1017 9412 8658 7904 715 6397 5643 4889 19875 1168 1092 1017 9412 8658 7904 715 6397 5643 4889
F4 Freezer Wall Simulation Output
INPUT PARAMETERS
Section Dimensions (mm) Width 5600 Length 2000 Depth 1000 Steel skin thickness 6500 Plastic skin thickness 2500
Mesh Geometry dx 2800 dy 2500 Number nodes in x-direction 20 Number nodes in y-direction 80 Number of steel skin nodes (including corner 00) 9 Steel nodes under the seal 2 to 8
Steel skin conductivity (Wm K) 5400 Foam insulation conductivity (Wm K) 27000E-02 Plastic skin conductivity (Wm K) 1500 Outside h (Wm2 K) 6870 Inside h (Wm2 K) 6410 Outside Temp (C) 2100 Inside Temp (C) -1000
OUPUT PARAMETERS
108
Number of iterations 5409
Heat Transfer for the Section OVerall Heat Transfer (WI 4518 10 Heat Flux Thru Wall (Wm21 1362
Heat Transfer Along Metal Skin Under Seal node to node
2 3 3 4 4 5 5 6 6 7 7 8
Maximum difference
qm[Wm2) Om(W) 3026 1967 3008 1955 2981 1938 2944 1914 2892 1880 2820 1833
(1 6799
Edge loss computed from qe=q20-q1D 1760
Edge loss compusteel skin AT
ted directly from at centerline 2981
Heat fluxes in thru the section along the centerline [Wm2)
j flux UO 0 7762 5698 1 3711 2724 2 5678 41 68 3 7275 5341 4 8508 6246 5 9437 6927 6 1013 7438 7 1066 7823 8 1106 8117 9 1137 8347 10 1162 8529 11 1182 8678 12 1199 8801 13 1213 8904 14 1225 8992 15 1235 9068 16 1244 9135 17 1252 9193 18 1259 9245 19 1266 9291 20 1271 9333 21 1276 9370 22 1281 9405 23 1285 9436 24 1289 9464 25 1293 9491 26 1296 9515 27 1299 9538 28 1302 9559 29 1305 9578 30 1307 9596 31 1310 9614 32 1312 9630 33 1314 9645 34 1316 9659 35 1318 9673 36 1319 9685 37 1321 9697
109
38 1323 9709 39 1324 9720 40 1325 9730 41 1327 9740 42 1328 9749 43 1329 9758 44 1330 9767 45 1332 9775 46 1333 9783 47 1334 97bull 90 48 1335 9797 49 1336 9804 50 1336 9810 51 1337 9816 52 1338 9822 53 1339 9828 54 1340 9833 55 1340 9838 56 1341 9843 57 1341 9847 58 1342 9852 59 1343 9856 60 1343 9859 61 1344 9863 62 1344 9866 63 1344 9870 64 1345 9873 65 1345 9875 66 1346 9878 67 1346 9880 68 1346 9882 69 1347 9884 70 1347 9886 71 1347 9888
72 1347 9889 73 1347 9891 74 1347 9892 75 1348 9893 76 1348 9893 77 1348 9894 78 1348 9894 79 1348 9894
j local Qwall [WI
-1 3067 0 -36774E-02 1 -40214E-02 2 -32314E-02 3 -25994E-02 4 -20859E-02 5 -16909E-02 6 -14144E-02 7 -12169E-02 8 -10589E-02 9 -90092E-03 10 -78242E-03 11 -70342E-03 12 -66392E-03 13 -58492E-03 14 -54542E-03 15 -50592E-03 16 -46642E-03 17 -42692E-03 18 -42692E-03
110
19 -38742E-03 20 -34792E-03 21 -30842E-03 22 -30842E-03 23 -30842E-03 24 -26892E-03 25 -26892E-03 26 -22942E-03 27 -22942E-03 28 -22942E-03 29 -22942E-03 30 -18992E-03 31 -1 8992E-03 32 -18992E-03 33 -18992E-03 34 -1 8992E-03 35 -1 5042E-03 36 -1 8992E-03 37 -15042E-03 38 -1 5042E-03 39 -11092E-03 40 -11092E-03 41 -11092E-03 42 -11092E-03 43 -11092E-03 44 -11092E-03 45 -11092E-03 46 -11092E-03 47 -71417E-04 48 -11092E-03 49 -71421E-04 50 -11092E-03 51 -71417E-04 52 -11092E-03 53 -71417E-04 54 -71421E-04 55 -71421E-04 56 -71417E-04 57 -31916E-04 58 -31920E-04 59 -31916E-04 60 -31916E-04 61 -71417E-04 62 -11421E-04 63 -71421E-04 64 -31920E-04 65 -31920E-04 66 -71417E-04 67 -31916E-04 68 -71417E-04 69 -31920E-04 70 -71421E-04 71 -31920E-04 72 -31920E-04 73 -71417E-04 74 -31916E-04 75 -31916E-04 76 -31916E-04 77 -31916E-04 78 -71417E-04 79 -71417E-04
Qwallfz [Wm2J = 2895 Qwallfz [WJ = 2721
111
Freezer Wan Nodal Temperatures
x(mm) y1mm 14 42 70 98 126 154 182 210 238 266
125 1507 1492 1477 1461 1445 143 1415 14 1385 1338 375 1519 1489 1458 1426 1392 1353 1307 1247 1154 972 625 1531 1486 1441 1393 1341 1282 1212 1121 9925 7989 875 1542 1484 1425 1363 1296 1221 1132 1023 8837 7014
1125 1553 1483 1412 1338 1258 117 1069 9508 809 6396 1375 1563 1483 1401 1317 1227 1129 102 8969 7563 5974 1625 1572 1483 1393 13 1202 1097 9824 8568 7184 5673 1875 1582 1485 1387 1287 1182 1072 9537 8269 6906 5452 2125 1591 1488 1384 1277 1167 1053 9321 8046 67 5288 2375 1599 1491 1382 1271 1157 1039 916 7881 6547 5164 2625 1608 1495 1381 1266 1149 1028 9041 7758 6433 5071 2875 1616 1499 1382 1264 1144 1021 8955 7668 6349 5002 3125 1623 1504 1384 1263 114 1016 8895 7604 6288 495 3375 1631 1509 1386 1263 1139 1013 8854 7559 6245 4913 3625 1638 1514 1389 1264 1138 1011 8829 753 6216 4888 3875 1645 1519 1393 1266 1139 1011 8816 7513 6198 4872 4125 1652 1524 1396 1269 114 1011 8813 7505 6188 4863 4375 1658 1529 14 1271 1142 1012 8817 7505 6185 486 4625 1664 1534 1405 1275 1144 1014 8826 751 6188 4861 4875 167 1539 1409 1278 1147 1016 884 752 6195 4867 5125 1676 1544 1413 1281 115 1018 8858 7533 6206 4875 5375 1682 1549 1417 1285 1153 102 8877 755 6219 4886 5625 1687 1554 1421 1289 1156 1023 8899 7568 6235 4899 5875 1692 1559 1425 1292 1159 1026 8923 7588 6252 4914 6125 1698 1563 143 1296 1162 1028 8947 7609 627 493 6375 1702 1568 1434 1299 1165 1031 8972 763 6289 4946 6625 1707 1572 1438 1303 1169 1034 8997 7653 6308 4964 6875 1712 1576 1441 1306 1172 1037 9022 7675 6329 4982 7125 1716 158 1445 131 1175 104 9048 7698 6349 5 7375 172 1584 1449 1313 1178 1043 9073 7721 6369 5018 7625 1724 1588 1452 1317 1181 1045 9098 7744 639 5036 7875 1728 1592 1456 132 1184 1048 9123 7766 641 5054 8125 1732 1595 1459 1323 1187 1051 9147 7788 643 5072 8375 1736 1599 1462 1326 1189 1053 917 781 645 509 8625 1739 1602 1465 1329 1192 1056 9194 7831 6469 5108 8875 1743 1605 1468 1332 1195 1058 9216 7852 6488 5125 9125 1746 1609 1471 1334 1197 1061 9238 7872 6507 5142 9375 1749 1612 1474 1337 12 1063 926 7892 6525 5158 9625 1752 1615 1477 134 1202 1065 9281 7911 6542 5174 9875 1755 1617 148 1342 1205 1067 9301 793 656 519 10125 1758 162 1482 1344 1207 1069 9321 7948 6576 5205 10375 1761 1623 1485 1347 1209 1071 934 7966 6593 522 10625 1763 1625 1487 1349 1211 1073 9358 7983 6608 5234 10875 1766 1627 1489 1351 1213 1075 9376 7999 6623 5248 11125 1768 163 1491 1353 1215 1077 9393 8015 6638 5262 11375 1771 1632 1494 1355 1217 1079 941 8031 6652 5275 11625 1773 1634 1496 1357 1219 1081 9426 8045 6666 5287 11875 1775 1636 1498 1359 1221 1082 9441 806 6679 53 12125 1777 1638 1499 1361 1222 1084 9456 8073 6692 5311 12375 1779 164 1501 1362 1224 1085 947 8087 6704 5322 12625 1781 1642 1503 1364 1225 1087 9483 8099 6716 5333 12875 1783 1644 1505 1366 1227 1088 9496 8111 6727 5344
112
13125 1784 1645 1506 1367 1228 109 9509 8123 6738 5353 13375 1786 1647 1508 1369 123 1091 9521 8134 6748 5363 13625 1788 1648 1509 137 1231 1092 9532 8145 6758 5372 13875 1789 165 151 1371 1232 1093 9543 8155 6768 5381 14125 1791 1651 1512 1373 1233 1094 9554 8165 6777 5389 14375 1792 1652 1513 1374 1235 1095 9564 8174 6785 5397 14625 1793 1654 1514 1375 1236 1096 9573 8183 6793 5404 14875 1794 1655 1515 1376 1237 1097 9582 8191 6801 5412 15125 1796 1656 1516 1377 1238 1098 959 8199 6808 5418 15375 1797 1657 1517 1378 1238 1099 9598 8206 6815 5425 15625 1798 1658 1518 1379 1239 11 9606 8213 6822 5431 15875 1799 1659 1519 138 124 1101 9613 822 6828 5436 16125 18 166 152 138 1241 1101 9619 8226 6834 5442 16375 18 1661 1521 1381 1242 1102 9626 8232 6839 5446 16625 1801 1661 1521 1382 1242 1103 9631 8237 6844 5451 16875 1802 1662 1522 1382 1243 1103 9637 8242 6848 5455 17125 1803 1663 1523 1383 1243 1104 9642 8247 6853 5459 17375 1803 1663 1523 1384 1244 1104 9646 8251 6857 5463 17625 1804 1664 1524 1384 1244 1105 965 8255 686 5466 17875 1804 1664 1524 1384 1245 1105 9654 8258 6863 5469 18125 1805 1665 1525 1385 1245 1105 9657 8261 6866 5471 18375 1805 1665 1525 1385 1245 1106 966 8264 6869 5474 18625 1805 1665 1525 1385 1246 1106 9662 8266 6871 5476 18875 1806 1666 1526 1386 1246 1106 9664 8268 6872 5477 19125 1806 1666 1526 1386 1246 1106 9666 827 6874 5479 19375 1806 1666 1526 1386 1246 1106 9667 8271 6875 548 19625 1806 1666 1526 1386 1246 1107 9668 8271 6876 548 19875 1806 1666 1526 1386 1246 1107 9668 8272 6876 5481
x(mm) v(mm) 294 322 350 378 406 434 462 490 518 546
125 549 054 -27 -5 -624 -727 -8 -85 -89 -92 375 548 171 -12 -338 -5 -624 -719 -795 -858 -914 625 51 22 -032 -24 -408 -543 -654 -748 -83 -907 875 474 238 0182 -175 -34 -482 -603 -71 -807 -898
1125 445 243 048 -132 -293 -436 -564 -68 -787 -89 1375 423 243 0653 -103 -259 -402 -534 -656 -772 -883 1625 406 24 0752 -084 -236 -378 -511 -638 -759 -877 1875 393 237 0808 -071 -219 -36 -495 -624 -749 -871 2125 382 233 0837 -063 -208 -348 -483 -614 -741 -867 2375 374 23 085 -058 -2 -339 -474 -606 -735 -863 2625 368 227 0855 -055 -195 -332 -467 -6 -731 -86 2875 363 225 0855 -053 -191 -328 -462 -596 -728 -858 3125 36 223 0853 -052 -189 -324 -459 -593 -725 -856 3375 357 221 0851 -051 -187 -322 -457 -59 -723 -855 3625 355 22 0849 -05 -186 -32 -455 -588 -722 -854 3875 354 219 0849 -049 -185 -319 -453 -587 -72 -853 4125 353 219 0849 -049 -184 -318 -452 -586 -72 -853 4375 353 219 0852 -049 -183 -317 -451 -585 -719 -852 4625 353 219 0855 -048 -183 -317 -451 -584 -718 middot852 4875 353 22 0861 -047 -182 -316 -45 -584 -718 -852 5125 354 22 0867 -047 -181 -315 -449 -584 -717 -851 5375 355 221 0875 -046 -181 -315 -449 -583 -717 -851 5625 356 222 0884 -045 -18 -314 -448 -582 -717 -851 5875 358 223 0894 -044 -179 -313 -448 -582 -716 -851 6125 359 225 0904 -043 -178 -313 -447 -582 -716 -851 6375 36 226 0915 -043 -177 -312 -447 -581 -716 -85
113
6625 362 227 0927 -042 -177 -311 -446 -581 -716 -85 6875 363 229 0939 -04 -176 -311 -445 -58 -715 -85 7125 365 23 0951 -039 -175 -31 -445 -58 -715 -85 7375 367 232 0964 -038 -174 -309 -444 -579 -715 -85 7625 368 233 0976 -037 -173 -308 -444 -579 -714 -85 7875 37 234 0989 -036 -172 -308 -443 -578 -714 -849 8125 371 236 1 -035 -171 -307 -442 -578 -714 -849 8375 373 237 101 -034 -17 -306 -442 -578 -713 -849 8625 375 239 103 -033 -169 -305 -441 -577 -713 -849 8875 376 24 104 -032 -168 -305 -441 -577 -713 -849 9125 378 241 105 -031 -168 -304 -44 -576 -712 -849 9375 379 243 106 -03 -167 -303 -439 -576 -712 -848 9625 381 244 107 -029 -166 -302 -439 -575 -712 -848 9875 382 245 109 -028 -165 -302 -438 -575 -712 -848 10125 384 246 11 -027 -164 -301 -438 -574 -711 -848 10375 385 248 111 -026 -163 -3 -437 -574 -711 -848 10625 386 249 112 -025 -163 -3 -437 -574 -711 -848 10875 387 25 113 -024 -162 -299 -436 -573 -711shy -848 11125 389 251 114 -023 -161 -298 -436 -573 -71 -848 11375 39 252 115 -022 -16 -298 -435 -573 -71 -847 11625 391 253 115 -022 -16 -297 -435 -572 -71 -847 11875 392 254 116 -021 -159 -297 -434 -572 -709 -847 12125 393 255 117 -02 -158 -296 -434 -572 -709 -847 12375 394 256 118 -019 -158 -296 -434 -571 -709 -847 12625 395 257 119 -019 -157 -295 -433 -571 -709 -847 12875 396 258 12 -018 -157 -295 -433 -571 -709 -847 13125 397 259 12 -017 -156 -294 -432 -57 -709 -847 13375 398 259 121 -017 -155 -294 -432 -57 -708 -847 13625 399 26 122 -016 -155 -293 -432 -57 -708 -846 13875 399 261 122 -016 -154 -293 -431 -57 -708 -846 14125 4 262 123 -015 -154 -292 -431 -569 -708 -846 14375 401 262 124 -015 -154 -292 -431 -569 -708 -846 14625 402 263 124 -014 -153 -292 -43 -569 -707 -846 14875 402 263 125 -014 -153 -291 -43 -569 -707 -846 15125 403 264 125 -013 -152 -291 -43 -569 -707 -846 15375 403 264 126 -013 -152 -291 -43 -568 -707 -846 15625 404 265 126 -012 -152 -291 -429 -568 -707 -846 15875 405 265 126 -012 -151 -29 -429 -568 -707 -846 16125 405 266 127 -012 -151 -29 -429 -568 -707 -846 16375 405 266 127 -011 -151 -29 -429 -568 -707 -846 16625 406 267 128 -011 -151 -29 -429 -568 -707 -846 16875 406 267 128 -011 -15 -289 -428 -568 -707 -845 17125 407 267 128 -01 -15 -289 -428 -567 -706 -845 17375 407 268 128 -01 -15 -289 -428 -567 -706 -845 17625 407 268 129 -01 -15 -289 -428 -567 -706 -845 17875 407 268 129 -01 -15 -289 -428 -567 -706 -845 18125 408 268 129 -01 -15 -289 -428 -567 -706 -845 18375 408 269 129 -01 -149 -289 -428 -567 -706 -845 18625 408 269 129 -001 -149 -288 -428 -567 -706 -845 18875 408 269 129 -001 -149 -288 -428 -567 -706 -845 19125 408 269 13 -001 -149 -288 -428 -567 -706 -845 19375 409 269 13 -001 -149 -288 -428 -567 -706 -845 19625 409 269 13 -001 -149 -288 -428 -567 -706 -845 19875 409 269 13 -001 -15 -288 -428 -567 -706 -845
114
FS Fresh Food Wan Simulation Output Including Anti-sweat Condenser Tube
INPUT PARAMETERS
Section Dimensions (mm) Hidth 4500 Length 2000 Depth 2960 Steel skin thickness 6500 Plastic skin thickness 2500
Mesh Geometry dx 2250 dy 2500 Number nodes in x-direction 20 Number nodes in y-direction 80 Number of steel skin nodes (including corner 00) 11 Steel nodes under the seal 2 to 10 Tube located at node 6
Steel skin conductivity (Him K) 5400 Foam insulation conductivity (Him K) 27000E-02 Plastic skin conductivity (Him K) 1500 Outside h (Hm2 K) 6870 Inside h (Hm2 K) 6700 Outside Temp (C) 2100 Inside Temp (C) 4000
OUPUT PARAMETERS
Number of iterations 602
10 Heat Flux Thru Hall (Hm2) 9132
Heat Transfer Along Metal Skin Under Seal node to node qm[Hm21 Qm[HI
2 3 -15052E+04 -2896 3 4 -15125E+04 -2910 4 5 -15198E+04 -2924 5 6 -15274E+04 -2939 6 7 3996 7688 7 8 3898 7500 8 9 3790 7292 9 10 3662 7045
Maximum difference () 1243
j qleft [HI qright [HI -1 -2957 7832 0 -92065E-02 -38838E-02 1 -77348E-02 -48044E-02 2 -51596E-02 -30284E-02 3 -32948E-02 -15188E-02 4 -1 9628E-02 -54201E-03 5 -98600E-03 16837E-03 6 -36442E-03 70ll8E-03 7 79586E-04 96757E-03 8 43478E-03 11452E-02 9 70118E-03 12340E-02 10 87877E-03 12340E-02
115
11 87879E-03 13228E-02 12 10564E-02 12340E-02 13 10564E-02 11452E-02 14 96759E-03 11452E-02 15 87877E-03 10564E-02 16 87879E-03 87877E-03 17 78999E-03 87877E-03 18 61238E-03 78999E-03 19 61240E-03 61237E-03 20 52359E-03 52358E-03 21 34598E-03 34598E-03 22 25719E-03 25717E-03 23 16838E-03 16839E-03 24 79586E-04 25 -98018E-04 26 -18681E-03 27 -27561E-03 28 -36442E-03 29 -54202E-03 30 -54202E-03 31 -7 1962E-03 32 -80842E-03 33 -8 9721E-03 34 -98602E-03 35 -10748E-02 36 -11636E-02 37 -12524E-02 38 -1 3412E-02 39 -1 4300E-02 40 -15188E-02 41 -1 5188E-02 42 -1 6076E-02 43 -16964E-02 44 -17852E-02 45 -1 7852E-02 46 -1 8740E-02 47 -19628E-02 48 -19628E-02 49 -19628E-02 50 -20516E-02 51 -21404E-02 52 -22292E-02 53 -22292E-02 54 -23180E-02 55 -23180E-02 56 -23180E-02 57 -24068E-02
79578E-04 -98018E-04 -1 8682E-03 -27561E-03 -45322E-03 -54202E-03 -71962E-03 -71962E-03 -8 9722E-03 -8 9722E-03 -10748E-02 -11636E-02 -12524E-02 -13412E-02 -14300E-02 -1 5188E-02 -16076E-02 -16964E-02 -16964E-02 -17852E-02 -18740E-02 -19628E-02 -20516E-02 -20516E-02 -21404E-02 -22292E-02 -22470E-02 -22381E-02 -22647E-02 -23358E-02 -23447E-02 -23802E-02 -24512E-02 -24690E-02
58 -23979E-02 -25223E-02 59 -24423E-02 60 -24246E-02 61 -24423E-02 62 -24779E-02 63 -25400E-02 64 -25400E-02 65 -25667E-02 66 -26199E-02 67 -26022E-02 68 -26111E-02 69 -26377E-02 70 -26022E-02 71 -26732E-02 72 -26821E-02 73 -26199E-02 74 -26643E-02
-25489E-02 -25755E-02 -25933E-02 -2 6199E-02 -26466E-02 -26643E-02 -26821E-02 -26910E-02 -27087E-02 -27265E-02 -27354E-02 -27443E-02 -27531E-02 -27620E-02 -27620E-02 -27709E-02
116
75 -26377E-02 -27709E-02 76 -26377E-02 -27709E-02 77 -26555E-02 -27709E-02 78 -26910E-02 -27620E-02 79 -26555E-02 -27620E-02
Qleft [ii] -3079 Qright [ii] 6756 Percent entering cabinet 1800
Fresh Food Nodal Temperatures (Condenser Tube)
x(mm) y(mm) 1125 3375 5625 7875 10125 12375 14625 16875 19125 21375
19875 126 1206 1154 1104 1055 1007 9608 9158 872 8294 19625 1259 1205 1153 1103 1054 1006 9602 9152 8715 8289 19375 1259 1205 1153 1102 1053 1006 9598 9149 8711 8285 19125 1259 1205 1153 1102 1053 1006 9596 9147 871 8284 18875 1259 1205 1153 1102 1053 1006 9596 9147 871 8284 18625 1259 1205 1153 1103 1054 1006 9599 915 8712 8286 18375 126 1206 1154 1103 1054 1007 9604 9154 8716 829 18125 1261 1207 1155 1104 1055 1007 9611 9161 8722 8295 17875 1263 1209 1156 1105 1056 1008 962 9169 873 8302 17625 1264 121 1158 1107 1058 101 9632 918 874 8311 17375 1266 1212 116 1109 1059 1011 9646 9193 8752 8322 17125 1269 1215 1162 1111 1061 1013 9663 9209 8766 8335 16875 1272 1217 1164 1113 1063 1015 9682 9226 8783 835 16625 1275 122 1167 1116 1066 1017 9704 9246 8801 8367 16375 1279 1224 117 1119 1069 102 9728 9269 8822 8386 16125 1282 1227 1174 1122 1072 1023 9755 9294 8845 8407 15875 1287 1231 1178 1126 1075 1026 9785 9322 887 843 15625 1292 1236 1182 113 1079 103 9818 9352 8898 8456 15375 1297 1241 1187 1134 1083 1034 9854 9385 8929 8484 15125 1302 1246 1192 1139 1088 1038 9892 9421 8962 8514 14875 1308 1252 1197 1144 1092 1042 9934 946 8998 8547 14625 1315 1258 1203 1149 1097 1047 9979 9502 9037 8583 14375 1322 1265 1209 1155 1103 1052 1003 9547 9078 8621 14125 1329 1272 1216 1162 1109 1058 1008 9595 9123 8662 13875 1337 1279 1223 1168 1115 1064 1014 9647 9171 8706 13625 1346 1287 1231 1176 1122 107 102 9703 9222 8753 13375 1355 1296 1239 1183 1129 1077 1026 9762 9277 8803 13125 1364 1305 1247 1191 1137 1084 1033 9824 9335 8856 12875 1374 1314 1256 12 1145 1092 104 9891 9396 8913 12625 1385 1325 1266 1209 1154 11 1047 9962 9462 8973 12375 1396 1335 1276 1219 1163 1109 1055 1004 9531 9037 12125 1408 1347 1287 1229 1173 1118 1064 1012 9605 9105 11875 1421 1359 1299 124 1183 1127 1073 102 9683 9176 11625 1434 1371 1311 1251 1194 1137 1082 1029 9765 9252 11375 1448 1385 1323 1263 1205 1148 1092 1038 9851 9332 11125 1462 1399 1336 1276 1217 1159 1103 1048 9943 9416 10875 1478 1413 135 1289 1229 1171 1114 1058 1004 9505 10625 1494 1429 1365 1303 1243 1184 1126 1069 1014 9598 10375 1511 1445 138 1318 1257 1197 1138 1081 1025 9696 10125 1528 1462 1397 1333 1271 121 1151 1093 1036 98 9875 1547 1479 1413 1349 1286 1225 1165 1106 1048 9908 9625 1566 1498 1431 1366 1302 124 1179 1119 106 1002
117
9375 1586 1517 145 1384 1319 1256 1194 1133 1073 1014 9125 1607 1537 1469 1402 1336 1272 1209 1147 1087 1027 8875 1629 1558 1489 1421 1355 129 1226 1163 1101 104 8625 1652 158 151 1441 1374 1308 1243 1179 1116 1054 8375 1676 1603 1532 1462 1394 1327 1261 1195 1131 1068 8125 17 1627 1555 1484 1415 1346 1279 1213 1148 1084 7875 1726 1652 1579 1507 1436 1367 1299 1231 1165 11 7625 1753 1678 1604 1531 1459 1389 1319 1251 1183 1116 7375 1781 1704 1629 1556 1483 1411 1341 1271 1202 1134 7125 1809 1732 1656 1581 1508 1435 1363 1292 1222 1152 6875 1839 1761 1684 1608 1533 146 1387 1314 1243 1172 6625 187 1791 1713 1636 156 1485 1411 1337 1264 1192 6375 1903 1823 1744 1666 1589 1512 1437 1362 1287 1214 6125 1936 1855 1775 1696 1618 1541 1464 1387 1312 1236 5875 197 1889 1808 1728 1649 157 1492 1414 1337 126 5625 2006 1923 1842 1761 1681 1601 1522 1443 1364 1285 5375 2043 196 1877 1795 1714 1633 1553 1473 1392 1312 5125 2081 1997 1914 1832 1749 1668 1586 1504 1422 134 4875 212 2036 1952 1869 1786 1704 1621 1538 1454 137 4625 2161 2076 1992 1909 1825 1741 1658 1573 1488 1403 4375 2203 2118 2034 195 1866 1782 1697 1611 1525 1437 4125 2246 2161 2077 1993 1909 1824 1738 1652 1564 1474 3875 229 2206 2123 2039 1955 1869 1783 1695 1606 1515 3625 2336 2253 217 2087 2003 1918 1831 1742 1651 1558 3375 2383 2302 222 2138 2055 197 1882 1793 1701 1606 3125 2432 2353 2273 2192 211 2026 1938 1848 1755 1658 2875 2482 2405 2328 225 217 2086 20 1909 1815 1715 2625 2533 2461 2387 2312 2234 2153 2067 1977 1881 178 2375 2586 2518 2449 2378 2304 2226 2142 2052 1955 1851 2125 264 2579 2516 2451 2381 2306 2225 2136 2039 1933 1875 2696 2642 2587 2529 2466 2396 2319 2232 2134 2026 1625 2753 2709 2664 2614 256 2497 2425 2341 2244 2133 1375 2811 278 2746 2708 2664 2611 2546 2468 2373 226 1125 2871 2854 2835 2811 278 2739 2685 2615 2524 2411 875 2932 2932 293 2923 2909 2885 2846 2787 2706 2595 625 2995 3014 3031 3045 3052 3049 3031 2989 2922 2824 375 3058 3098 3138 3175 3208 3234 3245 3223 3179 3109 125 3124 3185 3247 331 3373 3436 35 3483 3467 3451
x(mm) y(mm) 23625 25875 28125 30375 32625 34875 37125 39375 41625 43875
19875 7877 747 7071 6679 6294 5915 554 5168 4799 4432 19625 7872 7466 7067 6676 6291 5912 5538 5166 4798 4431 19375 7869 7463 7065 6674 6289 591 5536 5165 4797 443 19125 7868 7462 7063 6673 6288 591 5535 5165 4797 443 18875 7868 7462 7063 6673 6288 591 5535 5165 4796 443 18625 787 7463 7065 6674 6289 591 5536 5165 4797 443 18375 7873 7466 7067 6676 6291 5912 5537 5166 4797 443 18125 7878 747 7071 6679 6294 5914 5539 5167 4798 4431 17875 7884 7476 7076 6684 6298 5917 5542 5169 4799 4431 17625 7893 7483 7083 6689 6303 5921 5545 5172 4801 4432 17375 7903 7492 7091 6696 6309 5926 5549 5175 4803 4433 17125 7914 7503 71 6704 6316 5932 5553 5178 4806 4435 16875 7928 7515 7111 6714 6324 5939 5559 5182 4809 4436 16625 7943 7529 7123 6725 6333 5947 5565 5187 4812 4438 16375 796 7544 7137 6737 6343 5955 5572 5192 4815 444 16125 7979 7561 7152 675 6355 5965 558 5198 4819 4442
118
15875 8001 7581 7169 6765 6368 5976 5589 5205 4824 4445 15625 8024 7601 7188 6781 6382 5987 5598 5212 4829 4447 15375 8049 7624 7208 6799 6397 6 5608 522 4834 445 15125 8077 7649 723 6819 6414 6014 562 5229 484 4453 14875 8107 7676 7254 684 6432 603 5632 5238 4847 4457 14625 8139 7705 728 6862 6451 6046 5645 5248 4854 4461 14375 8174 7737 7308 6887 6472 6064 566 5259 4861 4465 14125 8211 777 7338 6913 6495 6083 5675 5271 4869 4469 13875 8251 7806 737 6941 6519 6103 5691 5283 4878 4474 13625 8294 7845 7405 6972 6545 6125 5709 5297 4887 4479 13375 834 7886 7441 7004 6573 6148 5728 5311 4897 4484 13125 8388 793 748 7038 6603 6173 5748 5326 4907 449 12875 844 7977 7522 7075 6634 62 5769 5343 4918 4496 12625 8495 8026 7566 7114 6668 6228 5792 536 493 4502 12375 8553 8079 7613 7155 6703 6258 5816 5378 4943 4509 12125 8615 8135 7663 7199 6741 6289 5842 5398 4956 4517 11875 868 8194 7716 7245 6781 6323 5869 5418 4971 4524 11625 8749 8256 7771 7294 6823 6358 5898 544 4986 4532 11375 8822 8322 783 7346 6868 6396 5928 5463 5002 4541 11125 8899 8392 7892 7401 6915 6435 596 5488 5018 455 10875 898 8465 7958 7458 6965 6477 5994 5514 5036 456 10625 9066 8542 8027 7519 7018 6521 6029 5541 5055 457 10375 9155 8624 81 7583 7073 6568 6067 557 5075 4581 10125 925 8709 8177 7651 7131 6617 6107 56 5095 4592 9875 9349 8799 8257 7722 7193 6669 6149 5632 5117 4604 9625 9454 8894 8342 7797 7257 6723 6193 5665 514 4617 9375 9564 8994 8431 7875 7325 678 6239 5701 5165 463 9125 9679 9098 8525 7958 7397 684 6288 5738 519 4644 8875 98 9208 8624 8045 7472 6904 6339 5777 5217 4659 8625 9927 9324 8727 8137 7551 6971 6393 5819 5246 4674 8375 1006 9445 8836 8233 7635 7041 645 5862 5276 4691 8125 102 9572 895 8334 7722 7115 651 5908 5307 4708 7875 1035 9706 907 844 7814 7192 6573 5956 5341 4726 7625 105 9846 9197 8552 7911 7274 664 6007 5376 4745 7375 1066 9994 933 867 8014 7361 671 6061 5413 4766 7125 1083 1015 947 8794 8121 7452 6784 6118 5452 4787 6875 1101 1031 9617 8925 8235 7548 6862 6178 5494 481 6625 112 1049 9773 9063 8356 765 6945 6241 5537 4834 6375 114 1067 9937 9209 8483 7757 7033 6308 5584 4859 6125 1161 1086 1011 9364 8618 7872 7126 638 5634 4887 5875 1183 1106 103 9528 8761 7993 7225 6456 5686 4916 5625 1207 1128 1049 9703 8914 8123 7331 6537 5743 4947 5375 1231 1151 107 9889 9076 8261 7443 6624 5803 498 5125 1258 1175 1092 1009 925 8409 7564 6717 5867 5015 4875 1286 1201 1116 103 9436 8567 7694 6816 5936 5053 4625 1316 1229 1142 1053 9637 8738 7833 6924 601 5094 4375 1349 1259 1169 1078 9853 8922 7983 7039 609 5138 4125 1384 1292 1199 1104 1009 912 8146 7164 6177 5186 3875 1422 1327 1231 1133 1034 9336 8321 7299 627 5237 3625 1463 1365 1266 1165 1062 957 8512 7445 637 5291 3375 1508 1407 1304 1199 1092 9824 8719 7603 6479 middot535 3125 1557 1453 1346 1237 1124 101 8943 7773 6595 5412 2875 1612 1504 1393 1278 116 104 9185 7956 6719 5478 2625 1673 1561 1444 1323 1199 1073 9446 8152 6851 5546 2375 1741 1624 1501 1373 1242 1108 9725 8359 6989 5617 2125 1818 1695 1565 1429 1289 1146 1002 8575 713 5687 1875 1906 1775 1636 149 1339 1186 1032 8792 727 5755 1625 2007 1868 1716 1556 1392 1227 1062 9001 7401 5818
119
1375 1125 875 625 375 125
2127 2271 2449 2679 2994 3436
1975 2103 226
2467 2776 3361
1807 1912 2032 2173 2333 2469
1629 1707 1788 1863 191
1868
1447 1501 1548 1575 1559 1454
1266 1301 1324 1324 1279 1163
109 1111 112
1107 1058 9548
9183 9311 934
9205 8813 8043
7514 7591 7611 7544 735
6956
5873 5918 5953 5988 6049 6199
F6 Freezer Wall Simulation Output Including Anti-sweat Condenser Tube
INPUT PARAMETERS
Section Dimensions (mm) Width Length Depth Steel skin thickness Plastic skin thickness
5600 2000 1580 6500 2500
Mesh Geometry dx dy Number nodes in x-direction Number nodes in y-direction Number of steel skin nodes (including corner 00) Steel nodes under the seal Tube located at node
2800 2500 20 80
11 2 to 10 6
Steel skin conductivity (Wm K)
Foam insulation conductivity (Wm K) Plastic skin conductivity (Wm K)
Outside h (Wm2 K) Inside h (Wm2 K) Outside Temp (C) Inside Temp (C)
5400 27000E-02 1500 6870 6410 2100 -1000
OUPUT PARAMETERS
Number of iterations 879
ID Heat Flux Thru Wall (Wm2) 1362
Heat Transfer Along Metal Skin Under Seal node to node qm[Wm2] Qm[W]
2 3 -15024E+04 -1543 3 4 -15111E+04 -1552 4 5 -15205E+04 -1562 5 6 -15310E+04 -1572 6 7 5828 5986 7 8 5690 5844 8 9 5535 5684 9 10 5348 5492
Maximum difference (Is) 1356
j qleft[W] qright[W] -1 -1566 5928
120
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63
0 -62085E-02 -31363E-02 -5 9522E-02 -40097E-02 -44286E-02 -30955E-02 -33621E-02 -21814E-02 -25242E-02 -1 4577E-02 -1 8767E-02 -9 6252E-03 -13815E-02 -58162E-03 -10387E-02 -31499E-03 -73398E-03 -1 6265E-03 -54353E-03 -10285E-04
-35309E-03 27805E-04 -23882E-03 65891E-04 -16265E-03 14208E-03 -1 24 55E-03 14207E-03 -48371E-04 14207E-03 -10285E-04 10398E-03 -10285E-04 10399E-03 -10281E-04 10398E-03 -48371E-04 65891E-04 -1 02 85E-04 27805E-04 -86465E-04 16377E-04 -48375E-04 -52182E-04 -86465E-04 -97886E-04 -1 2455E-03 -13979E-03 -1 7788E-03 -16645E-03 -19692E-03 -21597E-03 -24263E-03 -25786E-03 -30357E-03 -30357E-03 -33404E-03 -35309E-03 -3 7975E-03 -3 9879E-03 -41784E-03 -44450E-03 -45974E-03 -49402E-03 -50164E-03 -53592E-03 -54353E-03 -58162E-03 -58543E-03 -62733E-03 -62733E-03 -66923E-03 -66542E-03 -71493E-03 -70351E-03 -75303E-03 -74541E-03 -7 9111E-03 -77969E-03 -83301E-03 -81397E-03 -87491E-03 -85206E-03 -90919E-03 -88634E-03 -94728E-03 -92062E-03 -97775E-03 -95109E-03 -10158E-02 -98537E-03 -10463E-02 -1 0158E-02 -10768E-02 -1 04 63E-02 -11073E-02 -10692E-02 -11377E-02 -10996E-02 -11644E-02 -11225E-02 -1 1949E-02 -11492E-02 -12215E-02 -11758E-02 -12444E-02 -11949E-02 -12672E-02 -12177E-02 -12901E-02 -12368E-02 -13129E-02 -12596E-02 -1 3282E-02 -12748E-02 -1 351 OE-02 -1 2977E-02 -13701E-02 -13129E-02 -1 3853E-02 -13282E-02 -14005E-02 -1 3434E-02 -14158E-02 -13586E-02 -14310E-02 -1 3701E-02 -14463E-02
121
64 -1 3815E-02 -1 4577E-02 65 -1 392 9E-02 -14691E-02 66 -14005E-02 -14767E-02 67 -14120E-02 -14881E-02 68 -14196E-02 -14958E-02 69 -1 4272E-02 -15034E-02 70 -14310E-02 -15110E-02 71 -1 4386E-02 -1 5148E-02 72 -14424E-02 -15186E-02 73 -14463E-02 -15224E-02 74 -14501E-02 -1 5262E-02 75 -14501E-02 -1 5300E-02 76 -14539E-02 -15262E-02 77 -14539E-02 -15300E-02 78 -1 4539E-02 -15262E-02 79 -14501E-02 -1 5300E-02
Qleft [Wj -1653 Qright [Wj 5163 Percent entering cabinet 2380
Freezer Nodal Temperatures (Condenser Tube)
x(mm) y(mm) 14 42 70 98 126 154 182 210 238 266
19875 9606 8457 7334 6235 516 4107 3075 2064 107 00944 19625 9596 8448 7325 6227 5152 4099 3068 2056 1064 00882 19375 9591 8443 732 6222 5148 4095 3064 2053 106 00850 19125 9591 8443 732 6222 5147 4095 3064 2052 106 00847 18875 9596 8448 7325 6226 5151 4099 3067 2056 1063 00873 18625 9606 8457 7334 6235 5159 4106 3074 2062 1069 00928 18375 9621 8472 7347 6248 5171 4118 3085 2072 1078 01013 18125 9641 8491 7366 6265 5188 4133 3099 2085 109 01128 17875 9666 8514 7388 6287 5208 4152 3117 2102 1106 01272 17625 9696 8543 7416 6313 5233 4176 3139 2123 1125 01447 17375 9731 8577 7448 6343 5262 4203 3165 2147 1147 01652 17125 9772 8616 7485 6378 5295 4234 3194 2174 1173 01888 16875 9817 8659 7526 6418 5333 427 3228 2206 1202 02156 16625 9868 8708 7573 6462 5375 431 3265 224 1234 02455 16375 9924 8762 7624 6511 5421 4353 3306 2279 127 02786 16125 9985 8821 7681 6565 5472 4402 3352 2322 131 03149 15875 1005 8885 7742 6624 5528 4454 3401 2368 1353 03546 15625 1012 8954 7809 6687 5588 4511 3455 2418 1399 03976 15375 102 9029 7881 6755 5653 4573 3513 2472 145 04441 15125 1029 911 7958 6829 5723 4639 3575 253 1504 0494 14875 1038 9196 804 6907 5798 4709 3641 2592 1562 05474 14625 1047 9287 8128 6991 5877 4784 3712 2659 1623 06045 14375 1057 9385 8221 708 5962 4865 3787 2729 1689 06652 14125 1068 9488 832 7175 6052 495 3868 2804 1759 07297 13875 1079 9597 8424 7275 6147 504 3952 2884 1833 07981 13625 1091 9713 8535 738 6247 5135 4042 2968 1911 08704 13375 1104 9834 8651 7491 6353 5235 4136 3056 1993 09466 13125 1117 9962 8774 7608 6464 534 4236 315 208 1027 12875 1131 101 8902 7731 6581 5451 434 3248 2172 1112 12625 1146 1024 9037 786 6704 5568 445 3351 2268 1201 12375 1161 1038 9178 7995 6833 569 4566 3459 2369 1294
122
12125 1177 1054 9326 8136 6967 5818 4686 3572 2475 1392 11875 1194 107 9481 8284 7108 5951 4813 3691 2585 1494 11625 1211 1087 9642 8439 7256 6091 4945 3815 2701 1602 11375 1229 1104 981 86 7409 6237 5083 3945 2822 1714 11125 1248 1122 9985 8768 757 639 5227 4081 2949 1832 10875 1268 1141 1017 8943 7737 6549 5378 4222 3082 1954 10625 1288 1161 1036 9125 7911 6714 5534 437 322 2083 10375 1309 1181 1055 9314 8092 6887 5698 4524 3364 2217 10125 1331 1203 1076 9511 8281 7067 5868 4685 3514 2356 9875 1354 1225 1097 9716 8477 7254 6046 4852 3671 2502 9625 1378 1248 1119 9929 8681 7448 6231 5026 3835 2654 9375 1402 1271 1142 1015 8893 7651 6423 5208 4005 2813 9125 1428 1296 1166 1038 9113 7861 6623 5398 4183 2979 8875 1454 1321 1191 1062 9342 808 6832 5595 4369 3152 8625 1481 1348 1216 1086 9579 8308 7049 5801 4562 3333 8375 1509 1375 1243 1112 9826 8545 7275 6015 4764 3522 8125 1538 1403 127 1139 1008 8791 751 6238 4975 3719 7875 1568 1432 1299 1166 1035 9047 7755 6472 5196 3925 7625 1598 1462 1328 1195 1063 9314 8011 6715 5426 4142 7375 163 1494 1358 1224 1091 9591 8278 697 5667 4368 7125 1663 1526 139 1255 1121 9881 8556 7236 5919 4606 6875 1697 1559 1422 1287 1152 1018 8847 7514 6184 4855 6625 1731 1593 1456 132 1185 105 9151 7806 6462 5118 6375 1767 1629 1491 1355 1218 1083 9469 8113 6755 5394 6125 1804 1665 1527 139 1254 1117 9804 8435 7063 5686 5875 1842 1703 1565 1428 129 1153 1015 8774 7388 5995 5625 1881 1742 1604 1466 1329 1191 1052 9133 7732 6322 5375 1921 1782 1644 1507 1369 1231 1091 9511 8097 6669 5125 1962 1824 1686 1549 1411 1272 1133 9913 8485 7039 4875 2004 1867 173 1593 1455 1317 1176 1034 8899 7435 4625 2047 1912 1776 164 1502 1363 1223 108 9341 7859 4375 2092 1958 1823 1688 1552 1413 1272 1128 9816 8315 4125 2138 2005 1873 1739 1604 1466 1325 1181 1033 8807 3875 2184 2055 1925 1793 166 1523 1382 1238 1088 934 3625 2232 2106 1979 1851 1719 1584 1444 1299 1148 992 3375 2282 216 2037 1911 1783 1649 1511 1366 1214 1055 3125 2332 2215 2097 1976 1851 1721 1584 1439 1286 1125 2875 2384 2273 2161 2045 1925 1798 1663 152 1366 1202 2625 2436 2334 2229 212 2005 1883 1751 1609 1455 1288 2375 249 2397 2301 22 2093 1976 1849 1708 1554 1384 2125 2546 2463 2377 2287 2188 2079 1957 182 1666 1493 1875 2602 2532 2459 238 2293 2193 2079 1946 1793 16 17 1625 266 2605 2546 2482 2407 232 2215 2089 1939 176 1375 2719 2681 264 2592 2533 2461 2369 2253 2108 1928 1125 2779 2761 2739 271 2671 2618 2543 244 2305 2128 875 2841 2844 2844 2838 2822 2792 2739 2655 2535 2367 625 2903 293 2954 2974 2986 2984 2959 2899 2802 2658 375 2967 3018 3069 3117 316 3194 3209 3173 3108 3009 125 3032 3108 3186 3263 3342 3421 35 347 344 3412
x (nun) y (nun) 294 322 350 378 406 434 462 490 518 546
19875 -0865 -1811 -2743 -3663 -4573 -5474 -6368 -7257 -8141 -9022 19625 -0871 -1816 -2747 -3667 -4577 -5477 -6371 -7259 -8142 -9024 19375 -0874 -1819 -275 -3669 -4578 -5479 -6372 -726 -8143 -9024 19125 -0874 -1819 -275 -367 -4579 -5479 -6372 -726 -8144 -9025 18875 -0872 -1817 -2748 -3668 -4577 -5478 -6372 -7259 -8143 -9025
123
18625 -0867 -1812 -2744 -3664 -4574 -5476 -637 -7258 -8142 -9024 18375 -0859 -1805 -2738 -3659 -457 -5472 -6366 -7256 -8141 -9023 18125 -0848 -1796 -273 -3652 -4563 -5466 -6362 -7252 -8139 -9022 17875 -0835 -1784 -2719 -3642 -4555 -546 -6357 -7248 -8136 -9021 17625 -0819 -1769 -2706 -3631 -4546 -5451 -635 -7243 -8132 -9019 17375 -0800 -1752 -2691 -3618 -4534 -5442 -6342 -7237 -8128 -9017 17125 -0779 -1733 -2673 -3602 -4521 -5431 -6334 -7231 -8124 -9014 16875 -0754 -1711 -2654 -3585 -4506 -5418 -6323 -7223 -8119 -9012 16625 -0727 -1686 -2632 -3565 -4489 -5404 -6312 -7214 -8113 -9009 16375 -0697 -1659 -2607 -3544 -447 -5389 -6299 -7205 -8106 -9005 16125 -0664 -1629 -258 -352 -445 -5371 -6286 -7194 -8099 -9001 15875 -0627 -1596 -2551 -3494 -4428 -5353 -6271 -7183 -8091 -8997 15625 -0588 -156 -2519 -3466 -4404 -5332 -6254 -717 -8083 -8993 15375 -0545 -1522 -2484 -3436 -4377 -531 -6236 -7157 -8074 -8988 15125 -0500 -148 -2447 -3403 -4349 -5287 -6217 -7143 -8064 -8983 14875 -0451 -1436 -2408 -3368 -4319 -5261 -6197 -7127 -8053 -8977 14625 -0399 -1388 -2365 -3331 -4287 -5234 -6175 -7111 -8042 -8971 14375 -0343 -1338 -232 -3291 -4253 -5206 -6152 -7093 -803 -8965 14125 -0284 -1284 -2272 -3249 -4216 -5175 -6127 -7074 -8017 -8958 13875 -0221 -1228 -2221 -3204 -4177 -5143 -6101 -7054 -8004 -8951 13625 -0155 -1168 -2168 -3157 -4137 -5108 -6073 -7033 -7989 -8943 13375 -0085 -1104 -2111 -3107 -4093 -5072 -6044 -7011 -7974 -8935 13125 -0011 -1037 -2051 -3054 -4048 -5034 -6013 -6987 -7958 -8927 12875 0065 -0966 -1988 -2998 -4 -4993 -598 -6963 -7941 -8918 12625 01474 -0892 -1922 -294 -3949 -4951 -5946 -6937 -7924 -8909 12375 0233 -0815 -1852 -2878 -3896 -4906 -591 -6909 -7905 -8899 12125 03229 -0733 -1779 -2814 -384 -4859 -5872 -688 -7885 -8888 11875 0417 -0648 -1702 -2746 -3782 -481 -5832 -685 -7865 -8877 11625 05157 -0558 -1622 -2675 -372 -4758 -5791 -6819 -7843 -8866 11375 06189 -0464 -1537 -2601 -3656 -4704 -5747 -6785 -7821 -8854 11125 07269 -0366 -1449 -2523 -3589 -4648 -5701 -675 -7797 -8841 10875 08398 -0263 -1357 -2441 -3518 -4588 -5653 -6714 -7772 -8828 10625 09577 -0156 -126 -2356 -3444 -4526 -5603 -6676 -7746 -8814 10375 1081 -0044 -116 -2267 -3367 -4461 -555 -6636 -7718 -88 10125 121 00732 -1054 -2174 -3286 -4393 -5495 -6594 -769 -8785 9875 1344 01957 -0943 -2076 -3202 -4322 -5437 -655 -766 -8769 9625 1484 03238 -0828 -1974 -3113 -4247 -5377 -6504 -7628 -8752 9375 1631 04575 -0708 -1867 -302 -4169 -5314 -6456 -7596 -8734 9125 1784 05974 -0582 -1755 -2923 -4087 -5247 -6405 -7561 -8716 8875 1944 07436 -0450 -1638 -2822 -4001 -5178 -6352 -7525 -8697 8625 2111 08966 -0312 -1516 -2715 -3911 -5105 -6296 -7487 -8676 8375 2286 1057 -0167 -1387 -2604 -3817 -5028 -6238 -7447 -8655 8125 2469 1224 -0015 -1253 -2486 -3718 -4948 -6177 -7405 -8633 7875 2661 14 0143 -1111 -2363 -3614 -4863 -6112 -736 -8609 7625 2861 1584 031 -0962 -2234 -3504 -4774 -6044 -7314 -8584 7375 3072 1778 04856 -0806 -2097 -3389 -468 -5972 -7265 -8558 7125 3293 1982 06704 -0641 -1954 -3267 -4581 -5896 -7213 -853 6875 3526 2196 08652 -0467 -1802 -3138 -4476 -5816 -7158 -8501 6625 3771 2422 1071 -0283 -1641 -3002 -4366 -5732 -71 -847 6375 403 2661 1288 -0089 -1471 -2858 -4248 -5642 -7038 -8437 6125 4303 2914 1519 01168 -1291 -2705 -4124 -5547 -6973 -8402 5875 4593 3182 1763 03357 -11 -2542 -3991 -5445 -6904 -8365 5625 49 3467 2023 05686 -0896 -2369 -385 -5338 -683 -8326 5375 5227 3771 23 08169 -0678 -2185 -37 -5223 -6751 -8284 5125 5576 4095 2596 1082 -0446 -1988 -354 -5101 -6668 -8239 4875 5949 4442 2913 1366 -0198 -1778 -337 -4971 -6579 -8193 4625 635 4814 3254 167 00669 -1553 -3187 -4832 -6485 -8143 4375 6781 5215 3619 1997 03519 -1313 -2993 -4685 -6385 -809
124
4125 7246 5647 4014 2349 06577 -1055 -2785 -4528 -6279 -8036 3875 775 6116 444 2728 0986 -0780 -2565 -4362 -6168 -7978 3625 8299 6625 4902 3137 1339 -0486 -233 -4187 -6051 -7919 3375 8899 718 5404 3579 1717 -0173 -2082 -4003 -593 -7859 3125 9558 7787 595 4057 2122 01586 -1823 -3813 -5806 -7798 2875 1028 8455 6545 4573 2555 0508 -1553 -3618 -568 -7739 2625 1109 9192 7197 513 3014 0872 -1277 -3422 -5558 -7683 2375 12 1001 7912 5729 3497 1245 -1002 -3233 -5442 -7633 2125 1301 1093 8698 6373 3998 1618 -0739 -3059 -534 -7592 1875 1418 1196 9566 7058 4508 1975 -0503 -2914 -5262 -7564 1625 1552 1314 1053 778 5007 2292 -0319 -2818 -5218 -7554 1375 171 1452 116 8525 5462 2528 -0224 -2798 -5226 -7564 1125 19 1616 1281 9263 5815 2621 -0272 -2892 -5304 -7597 875 2136 182 1417 9928 5968 2477 -0537 -3151 -5478 -7651 625 244 2095 1569 1037 575 1953 -112 -3637 -5773 -7713 375 2845 2514 1726 1027 4873 0854 -2146 -4427 -6224 -7757 125 3384 3296 1814 8879 2904 -1057 -3745 -5602 -6885 -7725
F bull 7 Seal Simulation Source Code and Ouput
Program Seal
c This program simulates the heat transfer characteristics of an c idealized refrigerator door gasket The steady-state temperature c profile is determined numerically from a 2-D finite difference c code
cxxxxxxxxxxxxx Parameters and Variablesxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
integer NNNWnsurfijjlloopiters real emmissigmakhihoTiTodelsNN real depthareatolkair
parameter (N=6) parameter (NN=20) parameter (W=7) parameter (nsurf=4N-l) parameter (emmis=09) parameter (sigma=567e-8) parameter (k=03) parameter (kair=0026) parameter (hi=641) parameter (ho=687) parameter (Ti=1032) parameter (To=209) parameter (sNN=02) parameter (del=sNNNN) parameter (depth=10) parameter (area=deldepth) parameter (tol=10)
real x(Onsurf)y(Onsurf)len(ONOnsurf) real F(OnsurfOnsurf) real T(-lNN+lONN)radl(nsurf+l)rad(Onsurf) real Eb(Onsurf)bvector(nsurf+l)Amatrix(nsurf+lnsurf+l) real difasumqsumqtotqin(NN-l) real rlr2r3r4r5
125
real clc2c3c4c5c6c7
open (lfilemiddotGasketoutposition-rewind) open (2file=Gasket(q)outpositionmiddotrewind)
cxxxxxxxxxxxxx Determine Viewfactors xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
call Points(Ndelnsurfxy) call length(Ndelnsurfxylen) call Vfactor(NdelnsurflenF)
cxxxxxxxxxxxxx Resistors (C-m2W)
c Interior x- and y-directions rl=delk
c Exterior to outdoor ambient r2=1ho
c Exterior to indoor ambient r3-1hi
c Radiation r4=(1-emmis)emmis
c Air r5=delkair
xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
cxxxxxxxxxxxxx Guass-Siedel Iteration xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
c Begin massive loop to determine the steady-state temperature c distribution across the section First update the interior nodes c by considering the radiative heat transfer among the interior c surfaces The radiative transfer is updated by calling a routine c which computes the new radiosities every iteration Loop until c tolerance is met
c Initialize temperature field do 10 i=ONN
do 11 jONN T(ij)=50
11 continue 10 continue
do 15 j=ONN T(-1j)=250 T(NN+lj)=50
15 continue
c Set temperatures for row y=O and row y=NN do 20 i=ONN
T(iO)=fl(idel) T(iNN)=f2(idel)
20 continue
cxxxxxxxxxxxxx Begin Iteration xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
loop=l iters=l do while (loop eq 1)
c Update radiosities using new temps and update interior surface nodes
call Jsolver(FemmissigmaTNNNWnsurfradlradEb + bvectorAmatrix)
c interior corners cl=area (2rl) c2=arearl
126
c3=area (2rl) c4=arearl c5=arear4 c6=1(cl+c2+c3+c4)
T(WW)=c6(clT(W+lW)+c2T(W-lW)+c3T(WW+l)+ + c4T(WW-l)+c5(rad(0)-Eb(0raquo)
cl=arearl c2=area(2rl) c3=area(2rl) c4=arearl c5=arear4 c6-1(cl+c2+c3+c4) T(W+NW)=c6(clT(W+N+lW)+c2T(W+N-lW)+c3T(W+NW+l)+
+ c4T(W+NW-l)+c5(rad(N)-Eb(Nraquo) clarearl c2-area (2rl) c3-arearl c4=area(2rl) c5=arear4 c6=1(cl+c2+c3+c4) T(W+NW+N)=c6 (clT(W+N+lW+N)+c2T(W+N-lW+N) +c3T(W+NW+N+l)+
+ c4T(W+NW+N-l)+c5(rad(2N)-Eb(2Nraquo) cl=area(2rl) c2=arearl c3=arearl c4=area(2rl) c5=arear4 c6=1(cl+c2+c3+c4) T(WW+N)=c6 (clT(W+lW+N) +c2T(W-lW+N)+c3T(WW+N+l) +
+ c4T(WW+N-l)+c5(rad(3N)-Eb(3Nraquo)
c Interior surface y=W jl=l do 22 i=W+lW+N-l
cl=area(2rl) c2=area (2rl) c4=arearl c5=arear4 c7=arear5 c6=1(cl+c2+c4+c7) T(iW)=c6(clT(i+lW)+c2T(i-lW)+
+ c7T(iW+l)+c4T(iW-l)+c5(rad(jl)-Eb(jlraquo) jl=j1+1
22 continue
c Interior surface y=N+W jl=3N-l do 25 i=W+lW+N-l
cl=area(2rl) c2=area (2rl) c3=arearl c5=arear4 c7=arear5 c6=1(cl+c2+c3+c7) T(iW+N)=c6(clT(i+lW+N)+c2T(i-lW+N)+
+ c7T(iW+N-l)+c3T(iW+N+l)+c5(rad(jl)-Eb(jlraquo) jl=jl-l
25 continue
c interior surface x=W jl=4N-l do 30 j=W+lW+N-l
c2=arearl
127
c3=area (2rl) c4=area(2rl) c5-arear4 c7-arear5 c6-1(c2+c3+c4+c7) T(Wj)-c6(c7T(W+lj)+c2T(W-lj)+c3T(Wj+l)+
+ c4T(Wj-l)+c5(rad(jl)-Eb(jl))) jl=jl-l
30 continue
c interior surface x=W+N jl=N+l do 35 j-W+lW+N-l
cl=arearl c3=area(2rl) c4=area (2rl) c5-arear4 c7-arear5 c6-1(cl+c3+c4+c7) T(W+Nj)=c6(clT(W+N+lj)+c7T(W+N-lj)+c3T(W+Nj+l)+
+ c4T(W+Nj-l)+c5(rad(jl)-Eb(jl))) jl=j1+1
35 continue
c Interior air nodes do 37 j=W+lN+W-l
do 38 i=W+lN+W-l call sseqn(Tr5r5r5r5areaareaareaareaijNN)
38 continue 37 continue
c Solid nodes do 40 i=lNN-l
do 45 jlW-l call sseqn(TrlrlrlrlareaareaareaareaijNN)
45 continue do 50 j=W+N+lNN-l
call sseqn(TrlrlrlrlareaareaareaareaijNN) 50 continue 40 continue
do 55 j=WW+N do 60 i=lW-l
call sseqn(TrlrlrlrlareaareaareaareaijNN) 60 continue
do 65 i=W+N+lNN-l call sseqn(TrlrlrlrlareaareaareaareaijNN)
65 continue 55 continue
c Side boundaries do 70 j=lNN-l
call sseqn(Trlr2rlrlareaareaarea2area20jNN) call sseqn(Tr3rlrlrlareaareaarea2area2NNjNN)
70 continue
c Apply energy balance around the boundary of the gasket to determine c stopping criterium dif
dif-OO dif=dif+(area(2rl))(T(00)-T(01)) dif=dif+(area(2rl))(T(0NN)-T(0NN-l)) do 90 i=lNN-l
dif=dif+(arearl)(T(iO)-T(il)) dif=dif+(arearl)(T(iNN)-T(iNN-l))
128
90 continue dif=dif+(area(2r1raquo(T(NN0)-T(NN1raquo dif=dif+(area(2r1raquo(T(NNNN)-T(NNNN-1raquo
do 95 j=1NN-1 dif=dif+(arear2)(To-T(0jraquo dif-dif+(arear3)(Ti-T(NNjraquo
95 continue
print dif
c Stopping criterium if (dif It toll then
loop-O endif if (iters eq 10000) then
loop=O endif
iters=iters+1 end do
cxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx c Compute heat flux into the cabinet
qsum=OO asum=OO do 97 j=1NN-1
qin(j)=hiarea(T(NNj)-Ti) qsum=qsum+qin(j) asum=asum+area
97 continue qtot=qsumasum write(2) heat flux to interior [Wm2)qtot
do 100 j=NNO-l write(l) (T(ij)i=ONN)
100 continue
pause stop end
c----------------------------------------------------------------------shyc------~----------------------------------------------------------------
Subroutine Points(Ndelnsurfxy)
integer Nnsurfi real delincrx(Onsurf)y(Onsurf)
x(O)=OO y(0)=del2
c Points along y=O edge incr-OO do 10 i=lN
y(i)=OO x(i)=(del2)+incr incr=incr+del
10 continue
c Points along x=Ndel edge incr=OO do 20 i=N+12N
x(i)=Ndel
129
y(i)-(del2)+incr incr-incr+del
20 continue
c Points along y=Ndel edge incr=OO do 30 i=3N2N+l-1
y(i)-Ndel x(i)=(del2)+incr incr-incr+del
30 continue
c Points along x-O edge incr=OO do 40 i-nsurf3n+l-1
xli) -00 y(i)-laquo3del)2)+incr incr-incr+del
40 continue
return end
c----------------------------------------------------------------------shyc-----------------------------------------------------------------------
Subroutine length(Ndelnsurfxylen)
integer Nnsurfij real dellen(ONOnsurf)x(Onsurf)y(Onsurf)
c Special case surface 0 do 10 j=Onsurf
len(0j)=sqrtlaquox(0)-x(jraquo2+(y(0)-y(jraquo2) 10 continue
c Surfaces along y=O do 20 i=IN-l
do 30 j=Onsurf len(ij)=sqrtlaquox(i)-x(jraquo2+(y(i)-y(jraquo2)
30 continue 20 continue
c Special case surface N do 50 j=Onsurf
len(Nj)=sqrtlaquox(N)-x(jraquo2+(y(N)-y(jraquo2) 50 continue
return end
c----------------------------------------------------------------------shyc-----------------------------------------------------------------------
Subroutine Vfactor(NdelnsurflenF)
integer Nnsurfijjlj2 real dellen(ONOnsurf)F(OnsurfOnsurf)Lzero
c Determine viewfactors for special case of surface 0 Lzero=delsqrt(20) do 10 j=Onsurf
if (j eq 0) then F(Oj)=OO
elseif (j eq nsurf) then F(Oj)=(len(Oj)+len(10)-len(00)-len(ljraquo(2Lzero)
else F(0j)=(len(0j)+len(lj+l)-len(Oj+l)-len(ljraquo(2Lzero)
130
endif 10 continue
c Determine viewfactors for surfaces on edge y-O
do 20 i=IN-l do 30 j=Onsurf
if (i eq j) then F(ij)=OO
elseif (j eq nsurf) then F(ij)=(len(ij)+len(i+l0)-len(i0)-len(i+ljraquo(2de1)
else F(ij)=(len(ij)+len(i+lj+l)-len(ij+l)-len(i+ljraquo(2del)
endif sum=sum+F(ij)
30 continue 20 continue
c Determine viewfactors for all other surfaces do 40 iON-l
do 50 j=03N-l F(i+Nj+N)=F(ij)
50 continue do 60 j=3Nnsurf
F(i+Nj-3N)=F(ij) 60 continue
do 70 j=02N-1 F(i+2Nj+2N)=F(ij)
70 continue do 80 j=2Nnsurf
F(i+2Nj-2N)=F(ij) 80 continue
do 90 j=ON-l F(i+3Nj+3N)=F(ij)
90 continue do 100 j=Nnsurf
F(i+3Nj-N)=F(ij) 100 continue
40 continue
return end
c----------------------------------------------------------------------shyc-----------------------------------------------------------------------
Subroutine Jsolver(FemmissigmaTNNNWnsurfradlradEb + bvectorAmatrix)
integer NNNnsurfij real emmissigmaF(OnsurfOnsurf) real T(-INN+10NN)rad1(nsurf+l)rad(0nsurf) real Eb(0nsurf)bvector(nsurf+1)Amatrix(nsurf+lnsurf+l)surn
c Compute Eb for all surfaces do 10 i-ON-l
Eb(i)=sigma(T(i+WW) 4) Eb(i+N)=sigma(T(W+Ni+W)4)
10 continue incr=W+N do 20 i=0N-1
Eb(i+2N)=siqrna(T(incrW+N) 4) Eb(i+3N)=sigma(T(Wincr)4) incr=incr-1
20 continue
131
c Assign values to vector b do 30 i=Onsurf
bvector(i+l)-(emmis(l-emmisraquoEb(i) 30 continue
c Assign values to matrix A do 40 i-Onsurf
do SO j=Onsurf Amatrix(i+lj+l)--F(ij)
SO continue 40 continue
c Override diagonal terms do 60 i-Onsurf
sum-OO do 70 j-Onsurf
sum-sum+F(ij) 70 continue
Amatrix(i+li+l)-(emmis(l-emmisraquo+sum 60 continue
c Call routine to solve the set of equations for unknown JS call gaussy(Amatrixbvectorradlnsurf+l)
do 80 i=Onsurf rad(i)=radl(i+l)
80 continue
return end
c----------------------------------------------------------------------shyc-----------------------------------------------------------------------
Subroutine Gaussy(abxn) c
integer nkiimaxjkplusllplus real a(nn)b(n)x(n)amaxbtempatemp
+ aeon sum
do 28 k=l n amax=OO do 4 i=kn if(abs(a(ikraquo-abs(amaxraquo442
2 amax=a(ik) imax=i
4 continue if(abs(amax)-0le-15)101014
10 printO equations are not independent return
14 btemp=b(k) b(k)=b(imax) b(imax)=btemp do 18 j=kn
atemp=a(k j) a(kj)=a(imaxj)
18 a(imaxj)=atemp kplus=k+l if(k-n)222828
22 do 24 i=kplusn b(i)=b(i)-b(k)a(ik)a(kk) acon=a(ik) do 24 j=kn
24 a(ij)=a(ij)-a(kj)acona(kk) 28 continue
132
l=n 32 sum=OO
if(1-n)343838 34 lplus-1+1
do 36 j-lplusn 36 sum=sum+a(lj)x(j) 38 continue
x(l)-(b(l)-sum)a(ll) if(1-1)424240
40 1-1-1 goto 32
42 return end
c----------------------------------------------------------------------shyc-----------------------------------------------------------------------
Subroutine sseqn(TriplusriminusrjplusrjminusAiplus + AiminusAjplusAjminusijNN)
c This subroutine computes the temperature at node (ij) c given the temperatures of the surrounding nodes and c the resistances leading to these nodes
integer ijNN real T(-1NN+10NN)riplusriminusrjplusrjminus real AiplusAiminusAjplusAjminus real c1c2c3c4c5
c1=Aiplusriplus c2=Aiminusriminus c3=Ajplusrjplus c4=Ajminusrjminus c5=1(c1+c2+c3+c4)
T(ij)=c5(c1T(i+1j)+c2T(i-1j)+c3T(ij+1)+c4T(ij-1raquo
return end
c----------------------------------------------------------------------shyc----------------------------------------------------------------------shy
real function f1(x) c door BC
real x f1-18520 - 23413x
return end
c----------------------------------------------------------------------shyc----------------------------------------------------------------------shy
real function f2(x) c wall BC
real x f2=18128 - 3475x
return end
c----------------------------------------------------------------------shyc----------------------------------------------------------------------shy
133
Fresh Food Compartment Simulations Results
Run 1 The prescribed temperature profiles are
Wall 19203 - 1908 x Door 19203 - 1206 x
(x is in meters)
Outdoor Ambient = 210 degC Local Indoor Ambient = 1533 degC
Run 2 The prescribed temperature profiles are
Wall 18989 - 2024 x Door 19078 - 1326 x
(x is in meters)
Outdoor Ambient = 210 degC Local Indoor Ambient = 1496 degC
Run 3 The prescribed temperature profiles are
Wall 1895 - 1998 x Door 19053 - 1384 x
(x is in meters)
Outdoor Ambient = 208 degC Local Indoor Ambient = 1491 degC
Ayem~ Values Wall 1905 - 1977 x Door 1913 - 1384 x
(x is in meters)
Ave Outdoor Ambient = 209 degC Ave Local Indoor Ambient =1507 degC
Loss from Fresh Food == 10 W
134
Freezer Compartment Simulations Results
Run 1 The prescribed temperature profiles are
Wall 1821 - 343 x Door 18606 - 2354 x
(x is in meters)
Outdoor Ambient = 210 degC Local Indoor Ambient = 1029 degC
Run 2 The prescribed temperature profiles are
Wall 18182 - 3542 x Door 18544 - 2398 x
(x is in meters)
Outdoor Ambient = 210 degC Local Indoor Ambient = 1042 degC
Run 3 The prescribed temperature profiles are
Wall 17993 - 3452 x Door 18411 - 2272 x
(x is in meters)
Outdoor Ambient = 208 degC Local Indoor Ambient = 1024 degC
Ayera~e Values Wall 18128 - 3475 x Door 18520 - 23413 x
(x is in meters)
Ave Outdoor Ambient = 209 degC Ave Local Indoor Ambient = 1032 degC
Loss from Fresh Food = 157 W
135
AN INVESTIGATION OF HOUSEHOLD REFRIGERATOR CABINET LOADS
Brian Edward Boughton MS
Department of Mechanical and Industrial Engineering University of Illinois at Urbana-Champaign 1992
ABSTRACT
This thesis presents an analysis of the cabinet loads of a typical household refrigerator
freezer The thennalload on the cabinet during closed door conditions is investigated The
area of greatest focus is the door and wall edge region of the refrigerator where thennal
losses are greatest Conduction heat transfer into the refrigerator cabinet is quantified using
numerical computer simulations and experimental measurements The overall cabinet load
is detennined as well as specific loads for various pathways that sum to equal the total
Based on agreement between simulations and experiments the complete edge loss accounts
for approximately 30 of the overall cabinet load on the fresh food and freezer
compartments In addition to this primary finding percentages for heat leakage directly
through the door gaskets along the steel casing at the wall and door flanges along the steel
skin in the mullion section due to the presence of a mullion anti-sweat heater and due to
the presence of an anti-sweat condenser tube are detennined
iii
T ABLE OF CONTENTS
Page
LIST OF TABLESvii
LIST OF FIGURES viii
1 INTRODUCTION 1
2 LITERATURE REVIEW5
3 ONE-DIMENSIONAL WALL AND DOOR LOADS 7
31 One-dimensional Heat Transfer ModeL 7 32 Determination of Effective Heat Transfer Coefficients 8 33 Results 10
4 EXPERIMENTAL ANAL YSIS 12
41 Temperature Profile Measurements 12 42 Thermopile Testing 14 43 Thermocouple Drag Testing 16 44 Experimental Determination of qwall and qdoor 19 45 Experimental Determination of qmulloff 21 46 Experimental Determination of qmullon 24 47 Determination of qmisc 27
5 NUMERICAL SIMULATION28
51 Wall Model 28 52 Wall Simulation to Determine qwall 32 53 Wall Edge Simulation to Determine qtube 36 54 Door Seal Simulation to Determine qseal 40
6 DISCUSSION OF RESULTS 46
61 Comparison of Simulation Results with Experimental Data 48 62 Mullion Analysis 49 63 Seal Analysis 49 64 Anti-sweat Condenser Tube Analysis 49 65 Overall Cabinet Load 50
7 SUMMARY OF CONCLUSIONS 54
REFERENCES 55
v
TABLE OF CONTENTS (CONTINUED)
Page APPENDIX A FUMED SILICA INVESTIGATION 56
Al Introduction56 A2 Thermal Properties 56 A3 Experimental Method 57 A4 Theory57 A5 Test Apparatus 59 A6 Results 61 A7 Conclusions 65 A8 Thermal Diffusivity Newton-Raphson Iteration Source Code 65
APPENDIX B ONE-DIMENSIONAL SIMULATION SOURCE CODE AND OUTPUT 69
Bl Source Code 69 B2 Output 71
APPENDIX C TEST REFRIGERATOR DESCRIPTION 73
APPENDIX D DATA ACQUISITION AND CONTROL SYSTEM 77
APPENDIX E EXPERIMENTAL DATA AND PLOTS 79
El Temperature Profile Plots From Fixed Thermocouples 79 E2 Thermopile Data Reduction 81 E3 Experimental Determination of qwall and qdoor Details 82 E4 Temperature Profile Plots From Mullion Data (Heater Off) 84 E5 Temperature Profile Plots From Mullion Data (Heater On) 87
APPENDIX F NUMERICAL SIMULATION EQUATIONS AND CODE 92
Fl Finite-Difference Equations 92 F2 Wall Simulation Source Code 94 F3 Fresh Food Wall Simulation Output 102 F4 Freezer Wall Simulation Output 108 F5 Fresh Food Wall Simulation Output Including
Anti-sweat Condenser Tube 115 F6 Freezer Wall Simulation Output Including
Anti-sweat Condenser Tube 120 F7 Seal Simulation Source Code and Output 125
vi
LIST OF TABLES
Page
31 One-dimensional Model Parameters 8 32 Results from One-dimensional Load Analysis 10
41 Thermopile Output 16 42 Experimental Determination of qwall and qdoor 20 43 Experimental Results from Mullion Analysis 24 44 Experimental Results from Heater Analysis 26 45 Miscellaneous Loads 27
51 Wall Simulation Input 30 52 Input Values 32 53 Wall Simulation Results 33 54 Wall With Condenser Tube Simulation Results 36 55 Seal Simulation Input 42 56 Seal Simulation Results 43
61 Comparison of Simulation and Experimental Values for qwall and qdoor 48 62 Overall Cabinet Loads 51
A1 Average Fumed Silica Conductivity for Various Bulk Densities 63 A2 Average Fumed Silica Diffusivity for Various Bulk Densities 64
E1 Thermopile Raw Data 82
F1 Model Resistors 92
V1l
LIST OF FIGURES
Page 11 Door Seal Region Cross Section 3 12 Mullion Region Cross Section 4
31 Model Used To Calculate One-dimensional Load 7
41 SteelSkin Temperature Profile Thermocouple Placement 12 42 Steel Skin Temperature Plot for Fresh Food Compartment 13 43 Steel Skin Temperature Plot for Freezer 14 44 Thermopile Test Apparatus 15 45 Thermopile Placement ~ 16 46 Thermocouple Drag Test Apparatus 17 47 Drag Profiles (Fresh Food) 18 48 Drag Profiles (Freezer) 19 49 Heat Flow Paths in Mullion 21 410 Mullion Face Plate Cross Section 22 411 Mullion Temperature Profile 23 412 Electric Heater Location 25 413 Mullion Temperature Profile With Heater On (Center) 26
51 Wall Heat Conduction Model Sketch 29 52 Non-adiabatic Door Seal 31 53 Fresh Food Wall Temperature Distribution 34 54 Freezer Wall Temperature Distribution 35 55 Tube Location for Simulation 36 56 Fresh Food Wall Temperature Distribution
Including Warm Anti-sweat Tube 37 57 Freezer Wall Temperature Distribution
Including Warm Anti-sweat Tube 38 58 Load Due to Condenser Tube for Various Tube Placements 39 59 ~ercentage of Heat Entering Cabinet for Various Tube Placements 39 510 Seal Simulation Mesh Layout 40 511 Seal Cavity Mesh Details 41 512 Seal Temperature Distribution (Fresh Food) 44 513 Seal Temperature Distribution (Freezer) 45
61 Refrigerator System Load Graph 46 62 Cabinet Loads Graph 47
A1 Fumed Silica Test Apparatus 59 A2 Fumed Silica Test Facility Schematic 60 A3 Time vs Temperature for Unpacked Run 61 A4 Natural Log Time vs Temperature for Unpacked Run 62 A5 Conductivity vs Bulk Density 63 A5 Diffusivity vs Bulk Density 64
viii
LIST OF FIGURES (CONTINUED)
Page
C1 Location of Anti-sweat Devices and Overall Dimensions of Test Refrigerator 73
C2 Fresh Food Compartment Interior Dimensions 74 C3 Fresh Food Door75 C4 Freezer Interior Dimensions 76 C5 Freezer Door76
D1 Data Acquisition and Control System 78
E1 Steel Skin Temperature Plot for Fresh Food Compartment (Run 2) 79 E2 Steel Skin Temperature Plot for Fresh Food Compartment (Run 3) 80 E3 Steel Skin Temperature Plot for Freezer (Run 2) 80 E4 Steel Skin Temperature Plot for Freezer (Run 3) 81 E5 Mullion Temperature Profile Run 2 (Heater Off) 84 E6 Mullion Temperature Profile Run 3 (Heater Off) 85 E7 Mullion Temperature Profile Run 4 (Heater Off) 85 E8 Mullion Temperature Profile Run 5 (Heater Off) 86 E9 Mullion Temperature Profile Run 2 (CenterHeater On) 87 E10 Mullion Temperature Profile Run 3 (CenterHeater On) 88 E11 Mullion Temperature Profile Run 1 (LeftHeater On) 88 E12 Mullion Temperature Profile Run 2 (LeftHeater On) 89 E13 Mullion Temperature Profile Run 3 (LeftHeater On) 89 E14 Mullion Temperature Profile Run 1 (RightHeater On) 90 E15 Mullion Temperature Profile Run 2 (RightHeater On) 90 E16 Mullion Temperature Profile Run 3 (RightHeater On) 91
F1 Generic Nodal Resistor Network 92
IX
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1 INTRODUCTION
New regulations recently announced by the Department ofEnergy call for substantial
energy efficiency increases for household appliances by 1993 The refrigerator is of
particular interest since it is the largest household consumer of electricity and accounts for a
large part of the 8 of the electricity used in the US for food-cooling both residential and
commercial In addition to efficiency standards regulations are being imposed on the use
of CFCs completely banning their use by the year 2000 (Braswell 1988)
The objective of this thesis is to present an analysis of all heat transfer paths from the
surroundings to the interior food compartments of the refrigerator under closed door
conditions Both experimental and numerical methods are used as a means to determine the
overall cabinet load as well as the load due to each pathway The study is focused on a
particular unit for practical purposes However the methods implemented may be applied
to any make or model to aid in the search for high efficiency cabinets
All loads determined in this study are strictly cabinet loads and not the loads seen by the
refrigerator system The thermal load on the cabinet is comprised of three main parts (i)
the load due to the one-dimensional heat transfer through the walls and doors to the food
compartments away froin the edges (ii) the load due to edge effects that is heat transfer
into the food storage compartments via paths around the perimeter of the cabinet aperture
and (iii) other miscellaneous sources
(11)
The determination of qlD is straightforward and is discussed in detail in Chapter 3 The
edge load must be broken down into several parts for examination
qedge = qwall + qdoor + qseal + qrnullon + qtubeave (12)
where
qwall heat input due to conduction along the wall steel flange
qdoo heat input due to conduction along the door steel flange
qseal heat conduction directly through the door seal
1
heat input due to conduction in the mullion region with the additional input from an anti-sweat heater
qtubeave heat input due to cabinet anti-sweat condenser tube averaged over the cycle time
heat input due to cabinet anti-sweat condenser tube
heat input due to conduction in the mullion region electric heater off
It is assumed that an electric anti-sweat heater in the mullion region is in use for the entire
cycle The test unit chosen for this study required this region to be heated almost
continually to eliminate condensation This load is represented by qmulloo in Eq (12)
The load qmulloff is due to heat conduction to the interior compartments at the mullion
region when the electric heater is off Although this value does not appear in the edge load
definition it is still important to detennine for sake of comparison with the value of
qmulloo The load due to the presence of an anti-sweat condenser loop around the aperture
of the cabinet is defmed as qtube Since this load is present for the on cycle only it must be
integrated over the cycle time to be included in Eq (12) hence the tenn qtubeave
The tenn qroisc is expressed as
qmisc = qfanave + qdefrostave + qcompave (13)
where
qfanave heat input from the evaporator fan averaged over the cycle time
qdefrostave heat input from the defrost heaters averaged over defrost cycle time
qcompave heat input from elevated exterior walls near the running compressor
Figure 11 is a cross sectional drawing of the door seal area of the test refrigerator
examined to detennine qwalI qdoor and~ The figure includes materials and their
properties taken from Incropera and Dewitt (1985)
2
400 ~I-I~ 065~
065 Only dimension that is different for the freezer
200
kltWIm-K)
Outer Steel Skin 540 312~ Polyurethane Wall Insulation 0027 0015- Inner Plastic Skin 015 009~
~ Rubber Gasket 03 017fm1I ~ ~ Glass Fiber Door Insulation 004 0023
All dimensions in millimeters
1 in= 254mm
Fig 11 Door Seal Region Cross Section
3
Figure 12 is a drawing of the mullion region cross section of the test refrigerator examined
to detennine ltlmullon and ltlmulloff
FREEZER
Freezer Gasket
Fresh Food Gasket
FRESH FOOD COMPARTMENT
Fig 12 Mullion Region Cross Section
The remainder of this thesis is devoted to the analysis of the closed door cabinet loads and
the experimental and numerical techniques used for their detennination
An experimental investigation of fumed silica as an alternative insulation for the refrigerator
is presented in Appendix A Although this appears to be a departure from the main topic
a relation exists The desire of higher efficiency requires a search for equal if not better
cabinet insulations that do not incorporate the use of ozone damaging CFCs Testing is
done to detennine the thennal conductivity and diffusivity of fumed silica for several
densities
4
2 LITERATURE REVIEW
The new energy standards imposed by the Department ofEnergy have sparked research in
the area of refrigerator efficiency and alternative refrigerants A study by Turiel and
Heydari (1988) focused on several ways to improve the efficiency of refrigerator-freezers
and freezers
Various classes for the study were chosen however the paper presents extensive results for
the most common variety a top-mounted automatic defrost refrigeratorfreezer The
design options considered were those changes that can be incorporated into the existing
refrigerator design Two types of improvements are noted (i) changes that increase energy
efficiency by decreasing the heat transfer into the cabinet and (ii) changes that increase the
efficiency by reducing auxiliary electricity use or improving the refrigeration system Type
(i) changes include Foam insulation substitution increased insulation thickness double
door gaskets improved foam insulation evacuated insulation panels and reduced heat load
of through-the-door feature Type (ii) changes include High efficiency compressor
substitution adaptive defrost fan and fan motor improvement anti-sweat heater switch
increased evaporator surface area hybrid evaporator enhanced heat transfer surfaces
mixed refrigerants improved expansion valve fluid control valve two-compressor system
use of natural convective currents and location of compressor condenser and evaporator
fan motor
Turiel and Heydari used a model developed by Little (1982) to carry out the energy use
simulations This model is a steady-state energy use simulation which computes the heat
leakage to the cabinet and then determines the energy needed to maintain the interior
ambient temperatures dictated by the OOE test procedure Turiel and Heydari present the
energy consumption figures for a 18 cubic foot top-mounted automatic defrost
refrigeratorfreezer as a baseline case They find that 74 of the total energy is accounted
for by the compressor 11 is for the anti-sweat heaters 10 is for the fans and 5 is
for the defrost heaters for a total of 947 kWhyr Also about 10 of the compressor
energy use is for the removal of internal heat generated by the evaporator fan motor defrost
heater and anti-sweat heaters
Several subsequent simulations were performed each time adding a design option that was
projected to improve efficiency The improvement levels were added cumulatively and
results were given on compressor run time heat leakage rate into the cabinet compressor
5
power demand at the operating point fan motor operating power for the evaporator and
condenser fans anti-sweat heater power and total daily and annual energy consumption
The goal here was to achieve by the last level of improvement the minimum energy
consumption that is technologically feasible One important fmding for all product classes
tested the highest efficiency was obtained by the use of evacuated panels in the planar
walls For example for the top-mounted automatic defrost unit the minimum energy use
was 515 kWyr
Finally an energy usevolume relation was developed from a linear regression obtained
from simulation results The resulting fit was shown as
Energy Use = Cl + C2Adjusted Volume
The constant Cl indicates the direct energy use to remove the cabinet loads associated with
the fan motors and heaters The slope C2 is an indicator of the rate of change ofenergy use
with a change in the adjusted volume This value reflects the rate of cabinet heat gain The
adjusted volume is the volume of the fresh food compartment plus 163 times the volume
of the freezer Turiel and Heydari produced a series of regressions for all of the defined
levels of design improvements allowing easy comparison at a specific adjusted volume
6
3 ONE-DIMENSIONAL WALL AND DOOR LOADS
In this section the overall steady cabinet load is calculated without considering the addition
of edge loading This load qlD is dermed as the heat transfer from the exterior
environment to the interior of the refrigerator under nonnal closed-door operating
conditions through four primary conductive paths (i) fresh food compartment walls (ii)
freezer walls (iii) fresh food door and (iv) freezer door In a later chapter the load due to
edge loading will be examined more closely
31 One-dimensional Heat Transfer Model
The steady conductive heat transfer through the walls of the refrigerator cabinet is
computed using a simple computer program written by Qausing (1983) This program
estimates inside and outside effective heat transfer coefficients using a flat plate natural
convection correlation Using these coefficients and the material properties and dimensions
of the wall insulation the one-dimensional heat transfer through the cabinet walls is
approximated for the fresh food and freezer compartments Figure 31 shows the
resistances and boundary conditions use in the model
Fig 31 Model Used To Calculate One-dimensional Load
7
The model provides flexibility for varying several parameters This allows application to
various types of refrigerator walls and doors Table 31 lists the input and output
parameters for the model The source code of the simulation along with the output for
completed runs are included in Appendix B
Table 31 One-dimensional Model Parameters
Input Parameters
To K (F) Room ambient temperature
Ti K (F) Interior ambient temperature
LiDs m (ft) WalVdoor insUlation thickness
kiDs Wm-K (Btuhr-ft-F) WalVdoor insulation thermal conductivity
A m2 (ft2) Cabinet surface area
Output
beo Wm2K (Btuhr-ft2_F) Exterior convective heat transfer coefficient
bei Wm2K (Btuhr-ft2-F) Interior convective heat transfer coefficient
hro Wm2K (Btuhr-ft2_F) Exterior effective radiative heat transfer coefficient
hri Wm2-K (Btuhr-ft2_F) Interior effective radiative heat transfer coefficient
qlD W (Btuhr) Heat transfer rate through specified section
32 Determination of Effective Heat Transfer Coefficients
The simulation developed automatically estimates the inside and outside effective heat
transfer coefficients This effective value is the sum of the convective and radiative
components which are defined below
The radiative heat transfer coefficients are computed iteratively using eqs (31) and (32)
assuming (i) gray walls at temperatures T wi or Two with emissivities poundi and Eo (ii) black
surroundings at Ti or To and (iii) walls can see surroundings only
(31)
(32)
8
The convective heat transfer coefficients are estimated from a flat plate natural convection
correlation developed by Clausing (1983) In the laminar regime (Ra lt 1()9) the Nusselt
number based on the film temperature is given by Eq (33)
NUf = 052 Ra4 (33)
For the turbulent regime (Ra ~ 109) the Nusselt number becomes
NUf = 009 Raf3 (34)
where in both cases
Tw+T_ Film temperature T f == 2
Lc == Vertical surface characteristic length g == Gravitational acceleration f3 == Thermal expansion coefficient v == Kinematic viscosity Tw == Vertical wall surface temperature T_ == Outsideinside ambient temperature
kf == Air thermal conductivity
The film temperature characteristic length Nusselt number and Rayleigh number will
have different values for the inside surface compared with the outside surface of the
cabinet Therefore the inside and outside convective heat transfer coefficients are
determined separately from eqs (35) and (36)
(35)
- NUfo kfohco - (36)Leo
9
33 Results
The four primary regions analyzed are (i) the fresh food compartment walls (ii) fresh food
door (iii) freezer walls and (iv) the freezer door The values for the input parameters
ltLins kins A) are taken from a full-size unit that is used for the experimental analysis
presented in Chapter 4 The room temperature is used for the model parameter To Also
the fresh food ambient Tee and the freezer ambient Tfz are substituted for Ti when
suitable in order to closely simulate real operating conditions The results are given in
Table 32
Table 32 Results From One-dimensional Load Analysis
Input
Section TooC eF)
Tj degC eF)
Lins m (ft)
kins Wm-K (Btuhr-ft-OF)
A m2 (fi2)
Fresh Food 21 4 0045 0027 242 Walls (698) (392) (0148) (0015) (2605)
Fresh Food 21 4 0040 0040 089 Door (698) (392) (0131) (0023) (958)
Freezer 21 -10 0056 0027 110 Walls (698) (-140) (0184) (0015) (1184)
Freezer 21 -10 0040 0040 034 Door (698) (-140) (0131) (0023) (366)
Output
Section hco Wm2-K cBtuhr-ft2-Fl
hro Wm2-K iJtuhr -ft2-Fgt
hci Wm2-K (Btuhr-ft2-F)
hri Wm2-K 1Btuhr-ft2-F)
qlD W (Btuhr)
Fresh Food 130 544 198 461 209 Walls (23) (96) (35) (81) (713)
Fresh Food 144 542 218 463 117 Door (25) (95) (38) (82) (399)
Freezer 143 542 226 397 143 Walls (25) (95) (39) (70) (488)
Freezer 164 538 259 400 81 Door (29) (94) (46) (70) (276)
herro =687 Wm2 K (121 Btulhr-ft2-OF) Total qlD =550 W herrrr = 670 Wm2 K (118 Btulhr-ft2_0F) (1876 Btuhr)
herrrz = 641 Wm2 K (113 Btulhr-ft2-OF)
The load for our operating conditions is 550 W (1876 Btuhr) Once again this quantity
does not reflect the total cabinet load on the refrigerator cabinet Edge effects are analyzed
in detail in the following chapters Another important result is the values for the effective
10
inside and outside heat transfer coefficients which are simply the sum of the convective
and radiative components The outside coefficient is heffo the fresh food coefficient is
heffff and the freezer coefficient is hefffz These numbers are used whenever film
coefficients are needed for computations
11
4 EXPERIMENT AL ANALYSIS
This section presents an experimental study performed on a full-size household
refrigerator In Chapter 3 we defined the load due to heat transfer through the walls and
doors of the cabinet as qlD The purpose of this experimental analysis is to quantify qwalh
qdoor qmulloff and Qrnullon and Qmisc Three types of tests are performed to accomplish
this task Descriptions of each are presented separately in the sections that follow
41 Temperature Profile Measurements
The refrigerator is instrumented with many thermocouples in various key areas to give
temperatures across the steel skin and to compare and verify the thermopile tests outlined
in the next section The four primary paths along the steel flange that are examined are the
wall-side fresh food door-side fresh food wall-side freezer and the door-side freezer
Five Type T 36 AWG thermocouples are placed along the skin for each path Figure 41
is a detailed drawing of the location of the thermocouples
Wall side TICs Door side TICs with 5 mm spacing with 5 mm spacing
Fig 41 Steel Skin Temperature Profile Thermocouple Placement
The wire leads are oriented so they run perpendicular to the temperature gradient so as to
reduce any effects of conduction along the wire to the bead The temperature data are fed to
the data acquisition system Each channel is a thermocouple input and is scanned at a rate
of 5 times a second The data are smoothed automatically by the software in blocks of 10
12
points for an average temperature every 2 seconds A full description of the data
acquisition and control system is provided in Appendix D
Data are collected for several runs to provide a good base to detennine average values since
the test conditions vary slightly from run to run To get a good measurement of the
temperature profIles along the steel flange the unit is shut off at the beginning of the run
and allowed to drift to quasi-steady conditions The presence of a large amount of thennal
mass (see Appendix C) within the refrigerator provides for a stable interior ambient
temperature during data collection The outer ambient is controlled by the room thennostat
which keeps the laboratory at a constant temperature to within plusmn1degC
Figure 42 is an example plot of a run that gives the temperature profIles along the steel
skin on the wall-side and door-side for the fresh food compartment
193
192
G 191 ~
i 19
middot5 189F
188
Run I iii --0 - Door Profile
~Imiddotmiddotmiddotmiddotmiddotmiddotmiddott 0 Wall Profue
i ~ i - - T =19273 - 001206x i i-- door i If ~
=-r~r==L~r=I ~ I +~~=~~~~~~~~~ middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot
Outdoor Ambient = 210 degC Fresh Food Ambient =48 degC
187-+----+----J------I----+---~
o 5 10 15 20 25
x (mm) 1 in= 254 mm
Fig 42 Steel Skin Temperature Plot for Fresh Food Compartment
The dashed line represents a linear least-squares fit for the door data and the solid line is the
corresponding fit for the cabinet wall data Each data point in the plot represents the
average temperature at that point over a period of time at quasi-steady conditions
Similarly Figure 43 is a plot of the temperature profIles for the freezer
13
186
184
a 182
~
i 18
5 178~
176
174
Run 1 t-- 1 1 --0 - Door Profde
P~P1 0 Wall Profile
- -LLl--=-+--shy- - Tdo = 18606 - O02354x i
or ~
=c==-rc1 1 ltb 1 ~
~~r--r- -r---shy0 5 10 15 20 25
x (mm) 1 in= 2S4mm
Fig 43 Steel Skin Temperature Plot for Freezer
A total of six separate runs were perfonned three for the fresh food compartment and three
for the freezer Plots for the other runs are located in Appendix E
From the figures above for the fresh food compartment the slope on the wall-side is
slightly steeper than the slope on the door-side In fact this trend is seen for all the runs
Therefore the heat conduction along the metal skin into the cabinet along the wall is
somewhat greater than that of the door For the freezer the slopes are nearly equal hence
the heat conduction along the wall skin and the door skin are nearly the same
42 Thermopile Testing
Another simple but important test is the use of a thennopile to measure the average
temperature difference at various locations on the steel flange regions of the unit Figure
44 is a schematic of the thennopile test set-up The thennopile is constructed from 36
AWG copperconstantan thennocouple wire
14
-
CopperConstan$t Junctions 285 mPt
IOmm
10mmThermopile
IOmm
Digital Multimeter
1 in= 254mm
Fig 44 Thermopile Test Apparatus
Five junctions are used for the fresh food compartment and three for the freezer The
junctions are mounted 10 mm (039 in) apart from one another along the steel skin beneath
the door seal Figure 45 is a detailed drawing of the lateral location of the thermopile
junctions
15
1 in =254 mm
Fig 45 Thermopile Placement
The thennopile provides an average temperature difference across the junctions The
output voltage must frrst be divided by the number of pairs of junctions and then translated
into a temperature difference using a referencing chart for the thennocouple wire Table
41 is a summary of the results from these tests The output voltages are read accurately to
within plusmn0002 mV The raw data and data reduction procedure are given in Appendix E
Table 41 Thermopile Output
Test Conditions Fresh Food aT Freezer aT TodegC
(OF) TffoC
(OF) Tfzoc
(OF) aTwallff degC
(Of) aTdoorffoc
(OFgt aTwallfzoC
(Of) aTdoorfzoC
(OFgt
1 210 (698)
48 (406)
-88 (162)
026 (047)
024 (043)
037 (067)
041 (074)
2 210 (698)
37 (387)
-87 (163)
027 (049)
026 (047)
038 (068)
040 (072)
3 208 (694)
37 (387)
-93 (153)
027 (049)
026 (047)
038 (068)
040 ( 072)
Average Values 209 (696)
40 (392)
-90 (158)
0267 (0481)
0253 (0455)
0377 (0679)
0403 (0725)
43 Thermocouple Drag Testing
One final technique applied is thennocouple drag testing This is a more qualitative method
to supply insight into what exactly is happening when the compressor is pumping wann
16
refrigerant through the anti-sweat tube that lines the perimeter of the cabinet aperture The
main objective of this test is not to give accurate temperature proftle infonnation but
instead to detennine the placement of the condenser tube This is needed as an input for
the numerical simulation of this region The reason that the temperature are not accurate is
the fact that the thermocouple is being dragged across a surface where good thermal contact
may not occur and significant energy may be generated Figure 46 is a schematic of the
apparatus used for drag testing
Power Supply
Data Acquisition System
Outer Metal Skin
Potentiometer
Inner Plastic Skin
Condenser Tube
Fig 46 Thermocouple Drag Test Apparatus
This device is quite simple yet very effective The type T 36 AWG thennocouple begins
at the interior boundary of the steel skin beneath the seal on the wall-side of the cabinet
The potentiometer is turned by hand moving the thennocouple oqtward along the skin
The temperature and location are stored simultaneously this way The thennocouple is kept
17
pressed against the steel flange by the seal The linear translation of the thennocouple is a
function of the output voltage Voutbull
s = 2mllT Vout (41)Yin
r =radius of potentiometer post =30 mm (012 in)
nT = total number of turns of potentiometer = 10
Vin = input voltage = 05 V
Vout = output voltage
Drag tests are run on the wall steel skin for both the fresh food compartment and the
freezer Runs are perfonned at four separate times the first being when the compressor
turns on Figure 47 is a plot of the drag proflles across the wall-side skin in the fresh food
compartment Figure 48 is a plot of the profiles in the freezer compartment The same
trends are generally seen for both regions The freezer profiles are simply shifted down in
temperature values as expected The temperature peak seems to move through time to
settle near the center of the flange region under the seal
31
30
29
G
i 28~
27
26~
25
24
23
e
Ji ~ i i i 1middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotlmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddoti~~
---l- Time 4
o Time 2 rr
i
0 5 10 15 20 x (mm)
Fig 47 Drag Profiles (Fresh Food)
18
26~--------+---------~-------4--------~
i ~
Time 1 24
22
20
18
16~~------+---------~-------4--------~
4 __
~~Time3
middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot_middotmiddot_middotmiddotimiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot
Outer Seal Edge o
o 5 10 15 20
x (mm)
Fig 48 Drag Profiles (Freezer)
44 Experimental Determination of qwall and qdoor
The results from the temperature profile and thennopile testing are used to detennine qwall
and qdoor according to the following defmitions
qwall = qwallff + qwallfz (42)
(43)
Where qwal1ff = heat conduction along wall-side fresh food compartment steel flange
qwallfz = heat conduction along wall-side freezer compartment steel flange
qdoorff = heat conduction along door-side fresh food compartment steel flange
qdoorfz = heat conduction along door-side freezer compartment steel flange
The trends derived from the fixed profiles exhibit generally good agreement with the
temperature differences seen by the thennopile For the fresh food compartment the
thennopile displays a slightly larger AT than what is seen in the profiles and both give a
19
slightly larger temperature difference for the wall-side compared with the door-side For
the freezer the temperature differences match closely on the wall-side however the doorshy
side AT is shown to be somewhat less than the wall-side AT for the fIXed thennocouple
measurements where the opposite is seen from the thennopile The worst discrepancy is
on the order of 10 and is probably due to the fact that the thennopile gives an average temperature difference at several vertical locations on the wall whereas the other method is
at one vertical location only
Since the thennopile produces an average temperature difference across the steel skin its
output is used to detennine the heat flux into the cabinet The refrigerator casing is being
used as a heat meter Thus the flux along the skin in the fresh food compartment on the
wall-side is
kmiddot ATwallffqwallff = m (44)
Ax
The load qwallJf is Eq (44) multiplied by the cross sectional area This area is the
thickness of the steel casing multiplied by the perimeter that is exposed to the room
ambient This perimeter varies for each of the two paths that comprise qwall and the two
paths that comprise qdoor The other cabinet loads are computed in a similar way and are
given in Table 42 The details of these values are given in Appendix E
Table 42 Experimental Determination of qwall and qdoor
Section Load W (BtuIhr)
qwallJf 28 (96)
qwallJz 21 (72)
qwall 49 (168)
qdoorff 33 (112)
qdoorJz 33
1112)
qdoor 66 (224)
20
45 Experimental Determination of qmulloff
The region that lies between the fresh food compartment and the freezer is called the
mullion The front portion of the mullion is covered by a thin steel face plate to provide a
suitable interface for the door seal magnets In this section the load due to heat conduction
along the mullion steel skin into the freezer and fresh food compartment is detennined
based on the experimental data
The heat transfer rate qmulloff is sum of two parts The first component is the heat
conduction along the steel plate into the fresh food compartment and the second is the
conduction into the freezer
qmulloff = qmulloffff + qmullofffz (45)
Figure 49 schematically illustrates paths of these two components
FREEZER
FRESH FOOD COMPARTMENT
Fig 49 Heat Flow Paths in Mullion
21
Ten 36 A WG type T thennocouples are mounted from top to bottom across the steel face
plate Figure 410 shows the cross section of the plate and the location and numbering of
the thennocouples
FREEZER
1bennocouplesSteel Face (5 mm spacing from
Plate bottom edge)
Freezer Gasket
Fresh Food Gasket
10 50
FRESH FOOD COMPARTMENT
1 in =254 mm
Fig 410 Mullion Face Plate Cross Section
Data are gathered from the ten thennocouples when the unit is shut off and allowed to drift
to a quasi-steady ambient temperature A total of five runs were perfonned Figure 411 is
a sample plot of the quasi-steady temperature profile All other plots are contained in
AppendixE
22
116
Run 1 I 115 ICcIIIII114 iii t ~mull~ =12~7 - 00~654xa
~ 113
rrfIIJ~~If112i 5 )mullfz 1= 1081~ + OOdl25X 111111 ~
11 oo+-t--t-iH-+-lo-shyiii i i Room Ambient = 2184 degc
109 middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1middot Fresh Ambient = 381 OC
108
1 10
I I I I I Freezer Ambient =-832 degc
2 3 4 5 6 7 8 9
TIC
Fig 411 Mullion Temperature Profile
The plot also shows two linear equations These represent linear fits to each side of the
peak temperature at TIC 7 The slopes (shown in degCmm) are used to detennine the heat
conduction to each compartment by eqs (46) and (47)
lmulloffff = km A (aT) (46)ax offff
qmul)offfz = km AIll) (47)ax offfz
The cross sectional area is the product of the face plate thickness (10 mm 0039 in) and
the length of the mullion (717 mm 2825 in) The average slopes from all five runs are
used to detennine qmulloffff and qroullofffz The results are given in Table 43
23
Table 43 Experimental Results from Mullion Analysis
Load W (Btuhr)
09qmullofUz (31)
07qmulloffff (24)
16qmuIlorr (55)
46 Experimental Determination of qmullon
In this section the load due to heat conduction along the mullion steel skin into the freezer
and fresh food compartment when an anti-sweat heater is on is experimentally determined
The test unit is equipped with an electric anti-sweat heater to eliminate condensation in the
mullion region The heater is installed on the back side of the plate and may be switched on
manually when needed It is a wire resistor type rated at 10 watts
The heat transfer rate qmullon is composed of two parts The first component is the heat
conduction along the steel plate into the fresh food compartment and the second is the
conduction into the freezer similar to ~ul1off
qmuIlon = ~ullonff + qmuIlonfz (48)
The location of the wire heater and the heat transfer paths are shown in Figure 412
24
FREEZER
qmullonfz
qmullonff
FRESH FOOD COMPARTMENT
Fig 412 Electric Heater Location
A series of tests are perfonned while the heater is on and the refrigerator is cycling
nonnally Three runs are done at each of three separate locations along the mullion
laterally (i) LEFT dermed as 180 mm (71 in) from the left-hand side of the unit (ii)
RIGHT 180 mm (71 in) from the right-hand side of the unit (iii) CENTER at center of
the mullion Figure 413 is a plot of the temperature profile across the face plate when the
heater is on for a specific test run The plots for all other runs are provided in Appendix E
The plot shows two profiles These represent the upper and lower limits as the unit cycles
The upper limit occurs just before the compressor turns on while the lower limit is at the
point in time just before the compressor shuts off At all times in between the profile
oscillates between the two limits maintaining nearly the same shape Once again a linear
fit is applied to the data on the fresh food side and the freezer side
25
30 iii imiddot iii i
29
28
27
Run 1
T mu
ill~~ 11 f = 26707 + 010776x Tmu11ff = 3128 - 00793x
Z +_ a 26~
I ~
middotmiddotmiddotbull-middotbullimiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotimiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotimiddotmiddotmiddotimiddotmiddot
24
25
e 23~ =H-T+H~i=i=
iimiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotimiddotmiddot T 11 ff = 27435 - 009504x 22 Tmullfz =21865 + 01l786x I m~ iii
21 -lmiddotmiddotmiddotmiddotmiddotmiddotmiddot-tmiddot Upper Limlt 0
20 middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotjmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotimiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddott 0 Lower Limit
19
0 1 2 3 4 5 6 7 8 9 10
TIC I
Fig 413 Mullion Temperature Profile With Heater On (Center)
Heat fluxes are computed identically to the method in Section 45 using the average slopes
from all nine runs The minimum value occurs just before to compressor turns on while
the maximum value occurs just before the compressor shuts off during normal cycling
The load is averaged over the cycle time which is approximately 50 for the test unit and
laboratory conditions The results are given in Table 44
Table 44 Experimental Results from Heater Analysis
Lower Profile Average W
(BtuIhr)
Upper Profile Average W
ffituhr)
qmullonfz 73
(249) 53
(181)
qmullonff 23 (78)
26 (89)
96 (32 7)
79 (270)
qmullon 88
300)
26
47 Determination of Qmisc
The load qoisc is comprised of three main parts The first is the load due to the evaporator
fan motor The fan that moves cool air in the cabinet also adds a thennalload Fans of this
type in use range from 8 - 16 watts The fan of our test unit is rated at 92 watts This
value must be integrated over the cycle time The cycle time for the unit is approximately
50 for the test conditions Thus the value of qfanave is 46 watts
The load qdefrostave is not determined experimentally Instead an estimate is obtained from
a similar study done by Turiel and Heydari (1988) This value is 5 watts which is an
average of the defrost heater input over the defrost cycle The defrost cycle can range from
10 - 12 hours of compressor run-time
The fmalload qcompave is detennined by measuring the cabinet surface temperature at the
region surrounding the compressor and computing the heat transfer locally The value is
found to be 2 watts Table 45 summarizes the results
Table 45 Miscellaneous Loads
Load W CBtuhr)
46 qfanave (15middotU
50 qdefrostave _07Ql
20 qcompave (68)
116 Qmisc (395)
27
s NUMERICAL SIMULATION
In this chapter a two-dimensional numerical model which is used to simulate the steadyshy
state heat transfer in the wall near the door seal is discussed The results from the model
include a computation of qwallff qwallfz and the complete temperature distribution across
the section The model is also used to estimate the additional cabinet load due to the
presence of an anti-sweat condenser tube embedded beneath the outer casing that runs
along the perimeter of the unit A separate model is presented which is used to simulate the
two-dimensional heat transfer across the door seal cross section The results are used to
determine qseal
51 Wall Model
A finite-difference technique is used to approximate the steady-state temperature
distribution in the wall section The technique is applied to solve the governing steady
two-dimensional heat conduction equation (assuming constant conductivity with no
generation)
(51)
Equation (52) is the basic fmite-difference representation of the conduction equation in a
homogeneous medium of constant conductivity with no heat generation (White 1988) In
Appendix F a complete list of all the model difference equations is provided
2(1+(3)Tij = (3Tij+l + Ti+lj+(3Tij-l + (3Ti-lj (52)
where (3 = (llxlly)2
28
Figure 51 is a sketch of the model representation of the refrigerator wall at the door seal region The dimensions shown are flexible parameters in the model The model allows for
slight changes in the geometry as well as changes in mesh size in both x and y directions
However the mesh size must remain uniform across the section
s5 s6
sl
Fig 51 Wall Heat Conduction Model Sketch
For each of N unknown nodal temperatures N simultaneous linear algebraic equations are obtained for N unknowns If N is large as is the case for this simulation an iterative
technique is preferred to solve the system ofequations A Fortran program has been
written to carry out the finite-difference iteration A copy of the code is given in Appendix
F A simple Guass-Seidel technique is employed for the differencing iteration At each
iteration an energy balance is done for the entire section In theory this balance should be
29
zero (heat entering) = (heat leaving) The iteration is continued until the difference
between heat entering and heat leaving is equal to 1 of the total heat entering the section
Table 51 defines the input parameters for the simulation
Table 51 Wall Simulation Input
Code Parameter Definition
To C (F) Exterior surrounding ambient temperature
Ti C (F) Interior ambient temperature
lan Wm-K (Btuhr-ft-F) Steel skin conductivity
kp Wm-K (Btuhr-ft-F) Plastic skin conductivity
kins Wm-K (Btuhr-ft-F) Wall insulation conductivity
heffo Wm2-K (Btuhr-ft2-F) Outside effective heat transfer coefficient
hefti Wm2-K (Btuhr-ft2-F) Inside effective heat transfer coefficient
dm mm (in) Steel skin thickness
dp mm (in) Plastic skin thickness
dx mm (in) Mesh size x direction
dy mm (in) Meshsizeydirection
sl mm (in) Wall width
s2 mm (in) Wall length
b mm (in) Effective Perimeter
s3 mm (in) Seal indentation
s4 mm (in) Seal width
s5 mm (in) Depth of steel skin into cabinet along seal boundary
s6 mm (in) Width of plastic skin along seal boundary
The model assumes that the boundary that lies along the door seal is adiabatic This allows
the separation of the wall section from the rest of the geometry in this region The seal and
door can then be treated separately later A simple calculation is done to validate this
assumption
30
Steel Skin (Refrigerator wall)
Seal (k = 02 Wm-K)
Fig 52 Non-adiabatic Door Seal
A 2 degC temperature difference AT is imposed across the seal This is a slight overshy
estimate based on the experimental data An estimate of the conductive heat flux is
determined from Eq (53)
ATqerror=k- (53) Ax
qrror =02 Wm-C o~Cm =20 Wm2
The heat flux ql for the fresh food compartment is determined in Appendix E to be 14418
Wm2 Therefore qerror represents approximately 13 of the total flux Hence this
term is neglected in this study
Two other possible sources of error are associated with the fmite-difference technique itself
(Ozisik 1980) The fIrSt is called truncation error and arises from the discretization of the
second-order derivative in the steady conduction equation The second is referred to as the
round-offerror which is due to the fact that numerical calculations are carried out only to a
finite number of decimal places Repeated solution with smaller increments shows that the
truncation error is negligible The precision of the energy balance is evidence that the
round-off errors are negligible
31
S2 Wall Simulation to Determine qwall
The finite-difference model is used to detennine the wall-side heat transfer along the steel
skin However more valuable information is yielded from the simulation The nodal
temperature distribution is detennined which gives insight into the direction and magnitude
of heat fluxes throughout the section The fresh food compartment and the freezer are both
simulated to detennine qwallff and qwallJz respectively Table 52 is the list of the values
used for the model input parameters for both cases
Table S2
Code Parameter
To C eF)
Ti C eF)
kIn Wm-K (Btuhr-ft-F)
kp Wm-K (Btuhr-ft-F)
kins Wm-K (Btulhr-ft-F)
heffo Wm2-K (Btuhr-ft2_F)
heffi Wm2-K (Btuhr-ft2-F)
dm mm (in)
dp mm (in)
dx mm (in)
dy mm (in)
sl mm (in)
s2 mm (in)
b mm (in)
s3 mm (in)
s4 mm (in)
s5 mm (in)
s6 mm (in)
Input Values
Fresh Food 210 (698) 40
(392) 540 (312) 015 (009) 0027 0015t 687 (121) 670 (118) 065
(0026) 25
(0098) 225
(0088) 25
(0098) 450
(1772) 2000 (7874) 2960
(11653) 225
(0088) 2025 (0797) 225
(0886) 2025 (0797)
32
Freezer 210 (698) -10
(140) 540middot (312) 015 (009) 0027 (0015) 687 (121) 641 (113) 065
(0026) 25
(0098) 28
(0088) 25
Jo098) 540
(2125) 2000 (7874) 1580
(6220) 28
(0110) 196
JO772) 224
(088t) 288
(1134)
The output from the simulation includes the entire nodal temperature field heat fluxes at
each node along the centerline heat fluxes from node to node along the steel skin beneath
the door seal and the value for qwallff and qwallcz These heat transfer values and the
nodal temperature distribution are listed in Appendix F
The quantities qwallff and qwallcz are determined by computing the heat fluxes from node to node along the centerline of the section subtracting the one-dimensional flux and then
multiplying by the cross sectional area for that node and summing to give the total heat
transfer rate The primary results are shown in Table 53
Table 53 Wall Simulation Results
Section
The temperature distributions are shown in the following two figures Figure 53 shows
the temperature contour for the fresh food results Figure 54 is the same plot for the
freezer results
Since the geometry of the refrigerator door is similar to that of the wall along the edges the
heat leakage to the food compartments along the door flange can be approximated as being
roughly the same as qwall This approximation of qdoor is a good means of estimating the
two prime contributors to the edge loss for various different refrigerators which may have
slightly different geometries as well as different material properties
33
i
3875
3625
TemplaquogtC)
-e
11111
20
18
16 3375
g 3125 14 -5 2875 ~ 122625 ~
2375~ 102125~
1875 8
1625
1375 6
1125
875 4
625
375
SteeVPlastic Liner Interface
Fig 53 Fresh Food Wall Temperature Distribution
34
i 4875
4625
4375
4125
3875
3625
3375 -
3125e g 2875
2625 ~ 2375 ~ 2125c (I)
1875 ~ 1625
1375
1125
875
625
375
125
Fig 54 Freezer Wall Temperature Distribution
Temp(OC)
20
15
10
5
0
-5
-10
35
53 Wall Edge Simulation to Determine qtube
The wall simulation is modified to include a constant temperature node placed beneath the
steel flange to represent the presence of an anti-sweat condenser tube The simulation is
perfonned for the specific conditions that are typical of the test unit as well as a range of
lateral tube locations For the test refrigerator the tube is located as shown in Figure 55
and is at 35degC (95 OJlt)
Outer Steel Skin
14625 mm 1
Inner Plastic Liner
Fig 55 Tube Location for Simulation
The quantity qtube is detennined by taking the fluxes along the vertical line to the left of
the tube subtracting the one-dimensional flux and then multiplying by the cross sectional
area for that node and summing to give the total heat transfer rate Again the fresh food
compartment and the freezer must be simulated separately to produce a total governed by
Eq (54)
(54)
Program output for the fresh food and freezer simulations is given in Appendix F Table
54 summarizes the results from the model
Table 54 Wall With Condenser Tube Simulation Results
Section Load W iBtubrl
qtubeff 46
(157)
qtubefz 28 (96)
qtube 74 (253)
qtube8ve (ave for 50 cycle time)
37 (126)
36
-I i c IJ
~
r 4875
4625
4375
4125
3875
3625
3375
3125
2875
2625
2375
2125
1875
1625
1375
1125
875
625
375
125
TempfC)
SteeVPlastic Liner Interface
35
30
25
20
15
10
5
Fig 56 Fresh Food Wall Temperature Distribution Including Warm Anti-sweat Tube
37
TempfC)4875
4625
4375
4125
3875
3625
3375 - 31258
2875g 2625fo 2375
3 2125 d vI 1875
~ 1625
1375
1125
875
625
375
125
SteeVPlastic Liner Interface
Fig 57 Freezer Wall Temperature Distribution Including Warm Anti-sweat Tube
38
40
30
20
10
0
-10
The heat fluxes at each node along the vertical line to the left of the tube are also computed
by the simulation This value quantifies the amount of heat that is moving toward the outer
boundary and is used to determine the percentage of heat entering the cabinet For the test
refrigerator this value is 18 for the fresh food compartment and 24 for the freezer
Several more simulation runs were done to find the effect of lateral placement of the tube on
the overall heat transfer and the percentage of heat entering Figure 58 and Figure 59
show the trends that are found
-~ a tUbe ~middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotlmiddotmiddotmiddot=middotmiddot=pmiddotmiddotmiddot=middot-1- =1
middot middot middoti middot middotmiddotmiddotmiddotmiddotmiddotmiddotmiddot bull middotmiddotmiddot i middotmiddotmiddotmiddot middotmiddot middotmiddot ~ middotmiddot
middotmiddotrmiddot-rmiddot 0 lwbeff middotlmiddotmiddot~middot Gmiddottmiddotmiddot9middotlmiddot
i i -0- lwbe i middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotimiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddot fz tmiddotEimiddotmiddot ~G- -~ -q- -
0 5 10 15 20 25 x(mm)
Fig 58 Load Due to Condenser Tube for Various Tube Placements
8
~ - 7
50
a 6
~ 5
~ en 4 ~
pound ~ 3
2
- 26
~ a 24
middots bO
pound 22c ~
~ 20
a = 18sect ~
16 0 5 10 15 20 25
x (mm)
Fig 59 Percentage of Heat Entering Cabinet for Various Tube Placements
39
54 Door Seal Simulation to Determine qseal
Another model is developed for the two-dimensional heat transfer through the door seal
This model is very similar to the one created for the wall section Once again a fIniteshy
difference technique is utilized to detennine the temperature distribution at steady-state
conditions Even though the cross sectional geometry of the seal is simplifIed to a square
with a hollow square with a centrally located cavity no closed-form solution can be
applied Therefore a simulation is needed
The fInite-difference representation of the two-dimensional steady Eq (55) using central
differencing is given by Ozisik (1980)
Ti-lj - 2Tij + Ti+lj + Tij-l - 2Tij + Tij+l = 0 (55) Ax2 Ay2
For this model a square mesh is applied reducing Eq (55) to
Ti-lj + Ti+lj + Tij-l + Tij+l - 4Tij = 0 (56)
x
Fig S10 Seal Simulation Mesh Layout
40
The nodes along the vertical surfaces at x=O and x=20 are subject to the convective
boundary conditions and governed by Eq (57) and Eq (58) respectively
2~xheffol 2~heffo2Ti+lj + Tij-l + Tij+l - (4 + k TiJ = - k To (57)
seal seal
2~heffffl 2~heffff2Ti-lj + Tij-l + TiJ+l - (4 + kseal Tij = - kseal Tff (58)
The nodes along the top and bottom outside surfaces are held at the prescribed temperature
profIles which are detennined from experimental data (see Section 41) The interior nodes
are subject to radiant e~change among themselves and conduction through what is assumed
to be stagnant air A closer look at the model of the hollow interior of the seal is shown in
Figure 511
Fig 511 Seal Cavity Mesh Details
Each interior node corresponds to a single gray surface with assumed emissivity of 09
Viewfactors for all surfaces are computed automatically before the iteration begins For
each iteration the effect of radiation within the enclosure is taken into account by updating
surface radiosities Jij Thus for nodes on interior surfaces an extra tenn is added to the
governing difference equation (Eb is the blackbody radiation)
41
~(J - Eb )1-pound IJ lj
A code written in Fortran is used to perfonn Guass-Seidel iteration of the difference
equations to compute the temperature distribution at mesh nodes (Code listing in Appendix
F) Once again convergence is based on an energy balance applied to the entire section
The iteration is continued until the difference between heat entering and heat leaving is
equal to 01 of the total heat entering the section Table 55 lists the input parameters
used in the model The fresh food compartment and the freezer compartment are simulated
separately
Table 55 Seal Simulation Input
Code Parameter Fresh Food Freezer
Number of nodes along outside edge 20 20
Number of nodes along inside edge 6 6 1 1Lx = fly mm (in) (0039) (0039)
210 210Outdoor ambient temperature degC (oF) (698) (698) 150 105Indoor local ambient temperature degC COF) 590J j509)
Outdoor heat transfer coefficient W m2-K 687 687 (121) (121)(Btuhr-ft2-F)
Indoor heat transfer coefficient Wm2-K 670 641 (118) (113)(Btuhr-ft2-F)
Gasket interior surface emissivity 09 09 03 03Gasket conductivity Wm-K (Btuhr-ft-F) (0173) (0173)
Wall-side Temperature Boundary 1905 - 1977x 1813 - 3475x Condition degC Door-side Temperature Boundary 1913 - 1384x 1852 - 2341x Condition degC
42
The load results are summarized in Table 56 below The program output is listed in
AppendixF
Table 56 Seal Simulation Results
Load W Section (BtuIhr)
10 Qsealff (34)
ljQsealfz (Sn
25qseal (85)
The steady-state temperature distribution is shown in the figures below Figure 512 is the
fresh food simulation and Figure 512 is the freezer simulation The direction of the heat
flow through the section is easily seen from these plots
43
Wall-side Boundary Temperature (C)
~~
I 20
195
i 19t 0
8 ~ 1859 -- ~
isis ~ ampJ gtshy 18 ~
11 ~ S ~ 175~
~ 17
165
x(mm)
Door-side Boundary
Fig 512 Seal Temperature Distribution (Fresh Food)
44
Wall-side Boundary Temperature (C)
Ii 19
185
18i f IQ 5 IQ
175-is-is I s 17j ~
5e 0C= 165
~ ~ 16
155
x(mm)
Door-side Boundary
Fig 513 Seal Temperature Distribution (Freezer)
45
6 DISCUSSION OF RESULTS
The heat transfer values detennined from the experimental analysis and the numerical
simulations are the various components that embody the cabinet load on the refrigerator It
is important to separate cabinet loads from system loads The system load can be thought
of as the total electrical energy consumption of the unit It has four basic components (i)
the compressor (ii) fans (iii) anti-sweat heaters and (iv) defrost heaters The first two
components the compressor and fans are the cost of removing heat from the cabinet This
amount of heat is equal to the cabinet load divided by the COP of the system The typical
energy consumption is shown schematically in Figure 61
System Load (Energy Consumption)
Defrost Heater (averaged over time
cycles every 10-12 hours of compressorrurt-time)
TuneCycle
Fig 61 Refrigerator System Load Graph
In a study done by Turiel and Heydari (1988) the compressor and fans accounted for 84
of the total system load for an 180 cubic foot top-mounted refrigerator Staley (1992)
found this value to be 86 for a similar unit Both of these studies used system analysis to
determine these numbers The energy consumption of the components were monitored
during operation The energy consumption of our test refrigerator can be determined in a
reverse manner from the cabinet load data If a COP of 1 is assumed the test refrigerator
46
compressor and fans accounts for 86 of the energy consumption to cool the cabinet This
compares favorably with the fmdings of Turiel and Heydari (1988) and Staley (1992)
Figure 62 is a schematic of the cabinet loads One possible load that is not included in the
figure is the heat input associated with the defrost drain tube that runs through the back
wall However this term is probably small relative to the other contributors
Cabinet Load
qseal qdoor
qwall
qmullon
qdefrostave
Fig 62 Cabinet Loads Graph
All the loads are determined in this study from either experimental measurements
numerical simulations or both Most of the loads are quasi-steady that is they do not
fluctuate significantly over the cycle time of the refrigerator There are four loads shown in
Figure 61 that are cyclical in nature The three loads that appear only while the
compressor is running are qcomp qfarb and qtube Also the refrigerator is subjected to a
load every time ice build-up is removed by the defrost heaters This load is averaged over
its own cycle time and shown in the graph as qdefrostave
47
61 Comparison of Simulation Results with Experimental nata
The majority of the cabinet loads are detennined from experimental data with the exception
of qseal and qtube The wall and door flange loads aremiddot also found from the numerical
simulation (see Chapter 5) The two-dimensional model detennines the wall-side heat
transfer along the steel skin into the food compartments No model is available to directly
detennine the heat transfer on the door-side However since the flange geometry on the
door-side is similar to the wall the value for qwall is considered to be a good estimate for
qdoor Table 61 gives these values determined from experimental measurements and the
simulation
Table 61 Comparison of Simulation and Experimental Values for qwall and qdoor
Experimental Result W Simulation Result W (BtuIhr) (BtuIhr)
qwallff 28 (96)
28 (96)
qwallz 21 (72)
27 (92)
qwall 49 (168)
55 (188)
ldoorff 33
(112) 28 (96)
qdoorfz 33
(112) 27 (92)
qdoor 66 (224)
55 (188)
The model predicts qwall to within 57 of the experimental value The agreement of the
estimate of qdoor with the experimental value is within 90
Some of the shortcomings in the model used in this investigation are
(i) Only the wall is modeled Ideally the entire region should be considered including the
door and seal (see Figure 11)
(ii) The flange geometry is simplified The steel casing skin in the flange region may bend
in more complex ways Also the plastic liner varies in thickness near the door seal
(iii) The mesh must be unifonn There is no means to vary how fme the mesh can be The
ideal situation would be to have a fine mesh near the edges and a course mesh far from the
seal
48
62 Mullion Analysis
The single largest edg~ load is found in the mullion section (329 of qedge and 94 of
qtol) This load is due to the electric anti-sweat heater installed on the backside of the face
plate The heater is rated at 10 watts and approximately 88 of that input enters the
interior of the cabinet as a thennalload This is probably due to the small surface area
exposed to the room and the low amount of convective heat transfer in the channel between
the fresh food and freezer doors With the heater on 88 watts is measured enter the food
chambers With the heater off only 16 watts enters the interior The addition of the
heater increases the mullion load 55 times Generally it is not necessary to use the
mullion heater at all times However for the test environment the heater nearly all the time
to eliminate sweating under the laboratory conditions
63 Seal Analysis
The heat conduction directly through the seal accounts for the smallest portion of the edge
loss (94 ofqedge and 27 of qtol) The numerical model to detennine these values uses
a simplified representation of the complex cross sectional geometry of an actual door seal
The various air pockets are reduced to a single hollow void There is no experimental data
to verify the model However the numbers and trends resulting from the simulation are
reasonable
64 Anti-sweat Condenser Tube Analysis
Thennocouple drag tests were perfonned to give insight into the nature of the temperature
profIles at the wall steel flange with the presence of an anti-sweat condenser tube The wall
heat transfer simulation model was modified to include the effect of this tube The heat
conduction to the interior increased by 76 at the wall flange region The amount of
additional loading due to the tube depends on several parameters location of the tube
temperature of the circulating refrigerant and local wall geometry Although the model is
flexible enough to handle vari01~S temperatures and limited geometrical changes only the
influence of tube position was investigated As the tube is moved towards the interior the
load increases For the test refrigerator about 20 of the heat flow was directed to the
interior compartments primarily along the steel skin
49
6S Overall Cabinet Load
The overall cabinet load is defined as a sum of three parts
(61)
The edge load is
qedge = qwall + qdoor + Qseal + Qrnullon + qtubeave (62)
where
qwall
qtubeave
heat input due to the conduction along the wall steel flange
heat input due to the conduction along the door steel flange
heat conduction directly through the door seal
heat input due to conduction in the mullion region with the additional input from anti-sweat heater
heat input due to cabinet anti-sweat condenser tube averaged over the cycle time
heat input due to cabinet anti-sweat condenser tube
qmulloff heat input due to conduction in the mullion region electric heater off
The terms of Qrnisc are defined as
qmisc = qfanave + qdefrostave + qcompave (63)
where
qfanave heat input from the evaporator fan averaged over the cycle time
qdefrostave heat input from the defrost heaters averaged over defrost cycle time
qcompave heat input from elevated exterior walls near the running compressor
Table 62 presents the overall cabinet load analysis results
50
Table 62 Overall Cabinet Loads
Load W Load Btuhr Total
qlD 550 1876 591
qedge 265 903 285
Qwall 49155 167 188 53
Qdoor 66155 2251 188 71
Qseal 25 85 27
Qmullon 88 300 94
Qtubl ngt 37 126 40
qmisc 116 395 124
Qfanave 46 157 49
Qdefrost ave 50 170 54
qcomoave 20 68 21
qtot 931 3174 100
Simulation Results
All loads are detennined experimentally with the exception oflsea1 and qtubeave The
values for qwall and qdoor are detennined from both experimental data and numerical
simulations Edge loss per unit length along fresh food perimeter is 29 Wm (30 Btuhrshy
ft) the loss per unit length along the freezer perimeter is 44 Wm (46 Btuhr-ft) and the
loss along the mullion section is 123 Wm (128 Btuhr-ft) with the heater on and 22 Wm
(23 Btuhr-ft) with anti-sweat heater off
The largest single load is the one-dimensional conduction through the walls and doors
The edge load comprises 285 of the total a significant portion The largest edge load is
due to the electric anti-sweat heater that is installed in the mullion section The smallest
edge load is due to the heat conduction through the fresh food and freezer door seals The
losses at the wall-side and door-side flange regions account for 53 and 71 of the total
load respectively These could be considered together since the pathway of heat transfer is
very similar If that were the case the sum of qwall and qdoor would be the second largest
contributor to the overall cabinet load The influence of an anti-sweat condenser tube is
reflected in the value of qtubeave Although this additional load is larger than qwall it must
be integrated over the refrigeration cycle timewhich is 50 of the cycle time for the test
unit The tube boosts the heat transfer along the wall flange by 76
51
To round out the cabinet load three miscellaneous loads are considered The evaporator
fan motor produces a heat load within the cabinet which is considered to be equal to the
power rating of the fan The automatic defrost feature is another thermal load that is
cyclical appearing about every ten to twelve hours of compressor runtime The fmalload
is due to the elevated exterior skin temperature near the compressor when it is running All
three of these loads are averaged over their cycle times for comparison with other quasishy
steady loads As a total qmisc represents 124 of the overall cabinet load
Opportunities to decrease the one-dimensionalload are available The emphasis has been to
develop super-insulations to be installed in the refrigerators Some being considered are
vacuum panels aerogels and vacuum packed powder insulations The disadvantages of
this improvement lies within the need to develop a cost-effective technique for fabricating
and installing such technologies compatible with high-volume manufacturing Also edge
losses and panel connection losses must be minimized due to the difficulty in making a
panel the size of refrigerator interiors Reliability of the seal and perfonnance of the outer
envelope need to be ensured over a long period of time ie the expected life of the
product
The possibilities of reducing the loads along the edge of the refrigerator aperture are
somewhat less apparent One method of reducing quasi-steady heat conduction along wall
and door flanges is to raise the inside cabinet wall temperature by minimizing interior film
surface heat transfer coefficients This could be accomplished by the use of low-emissivity
surfaces on the interior walls or on sections nearest the edges The need for an anti-sweat
device for the perimeter is also eliminated supplying a two-fold savings by reducing the
cabinet ioad and the system energy consumption The need for an electric mullion heater
might also be done away with by the same means The drawback again would be to make
such modifications acceptable and cost-effective for manufacture
The remaining miscellaneous loads provide some chance for improvement If the
efficiency of the fans is increased the energy use of the refrigerator can be reduced The
option of moving the fan motor outside the cabinet leads to other problems The motor
shaft must pierce the wall providing another path for heat leakage Also frost built-up on
the shaft would be a costly and difficult problem to eliminate If the compressor and
condenser were located near the top of the refrigerator they can operate more efficiently
Heat can be more readily convected away eliminating the need for the condenser fan
(Turiel and Heydari 1988) Frost fonnation in the freezer varies significantly depending
52
on the ambient conditions and the freezer usage The defrost cycle could be made more
energy efficient with the addition of adaptive controls All of these improvements would
require redesign of the product and the manufacturing process This is a very expensive
alternative which would need to be justified by the associated energy savings
53
7 SUMMARY OF CONCLUSIONS
The following is a list of the important findings produced from this study
(i) The edge loading accounts for a significant portion of the total cabinet load For the
test unit used in this study an 18 cubic foot top-mount refrigerator this load was
approximately 30 of the total load The load includes losses along the wall and door
flanges conduction through the door seal mullion loading with an electric anti-sweat
heater on and additional thennal input from an anti-sweat perimeter condenser tube
(ii) The presence of an electric anti-sweat mullion heater boosts the mullion loading by
a factor of approximately 5
(iii) The presence of an anti-sweat condenser tube around the perimeter of the refrigerator
increases the wall flange load by approximately 75
(iv) The presence of the door air damt reduces the temperature difference across the door
seal to 35 of the temperature difference between the interior and exterior
environments
(v) The hypothetical elimination of the additional load due to the electric anti-sweat
mullion heater reduces the edge loading to approximately 22 of the total cabinet
load
(vi) The hypothetical elimination of the load due to the anti-sweat condenser tube reduces
the edge loading to approximately 25 of the total cabinet load Ifboth anti-sweat
devices were not needed the edge loading would be further reduced to only 17 of
the total
(vii) During the course of this investigation it was concluded that the experimental and
numerical methods developed are applicable to most refrigeratorfreezers that are
produced today
t The portion of the door liner that extends into the cabinet along the wall
54
REFERENCES
Braswell A 1988 Impact of CFC Regulations on the Air Conditioning and Refrigeration Industry International Jow-nal ofRefrigeration Vol 11 No6 p 385
Cabot Corporation 1987 CAB-O-SIL Fumed Silica Properties and Functions Tuscola n pp 12-15
Clausing A M 1983 Natural Convection Correlations for Vertical Surfaces Including Influences of Variable Properties ASME Jow-nal ofHeat Transfer Vol 105 No 1 pp 138-143
Incropera FP and Dewitt DP 1985 Fundamentals ofHeat and Mass Transfer Second Edition John Wiley and Sons New York
Ingersoll LR Zobel OJ and Ingersoll AC 1954 Heat Conduction with Engineering and Geological Applications McGraw-Hill Book Company New York
Little AD Inc 1982 Refrigerator and Freezer Computer Model Users Guide Cambridge Massachusettes
Micropore International Ltd Microtherm Thermal Insulation Worcestershire England Section 1
Nix GH Lowery GW Vachon RI and Tanger GE 1967 Direct Determination of Thermal Diffusivity and Conductivity with a Refined Line-Source Technique Progress in Astronautics and Aeronautics (Vol 20) Thermophysics ofSpacecraft an Planetary Bodies Academic Press New York pp 865-878
Nix GH Vachon RI Lowery GW and McCurry TA 1968 The Line-Source Method Procedure and Iterative Scheme for Combined Determination of Conductivity and Diffusivity Thermal Conductivity Proceeding of8th Conference
Ozisik MN 1980 Heat Conduction Wiley-Interscience Publishing New York pp 486-487
Staley D 1992 Personal Communication Graduate Research Assistant University of Illinois Urbana
Turiel I Heydari A 1988 Analysis of Design Options to Improve the Efficiency of Refrigerator-Freezers and Freezers ASH RAE Transactions Vol 94 Part 2
Van der Held EFM and Van Drunen FG 1949 Physika Vol 15 No 10 p 865
White PM 1988 Heat and Mass TranSer Addison-Wesley Publishing Reading Mass pp 145-160
55
APPENDIX A FUMED SILICA INVESTIGATION
A ~ 1 Introduction
Fumed silica is a micro-porous powder comprised of submicron particles of amorphous
silica bonded together in a cellular structure Several grades of silica are available offering
a selection ofdifferent grain sizes and chemical treatments Fumed silica is commonly used
to provide thickening thixotropy suspension and other related properties in liquid
systems In dry systems it is used to promote free flow frictionizing and anti-blocking
properties Thus it is a versatile additive in materials such as inks coatings adhesives~
and silicon rubber (Cabot Corporation 1987)
The thermal insulating properties of this material have been somewhat less widely applied
however fumed silica as an insulation displays some interesting properties Fumed silica
insulations are commercially available and have become a more popular material for certain
specific applications In this section the results of an investigation of the thermal
properties of one type of fumed silica is presented
A2 Thermal Properties
As an insulator fumed silica uses the microporous principle to reduce thermal conduction
to the theoretically lowest possible levels (Micropore International Ltd 1988) Most
conventional insulations rely upon voids normally occupied bj alt aS the meanS ot
minimizing heat transfer through the material Therefore it is important to maintain these
voids for maximum insulation Fumed silica is comprised of tiny spheres with diameters
of the same order of magnitude as the mean free path of the molecules in the air
Therefore when these spheres are packed closely together gaseous conduction and
convection are minimized The cell size is sufficiently small to keep convective currents
from forming and to trap gas molecules to rebound elastically thereby not imparting their
energy to slower moving molecules In addition solid conduction is minimized by the fact
that silica is a material with intrinsically low thermal conductivity These unique properties
make fumed silica an attraCtive alternative to conventional insulations
56
A3 Experimental Method
Thennal conductivity and thennal diffusivity are the properties detennined from our
experimental study Many methods exist for establishing the thennal properties of a given
substance Both steady-state and transient procedures are available The hot-wire method
is a the transient procedure used in this study
The practical form of the hot-wire method is given by Van derHeldand Van Dronen
(1949) who used it to detennine conductivities of liquids Nix et al (1967) elaborated to
give a method for the simultaneous detennination of both thennal conductivity and thennal
diffusivity Therefore it is possible to detennine both conductivity and diffusivity by
passing a known amount ofcmrent through a heater wire embedded in the test material and
recording the temperature at a point on the wire and at a fixed point from the wire over the
period of the test From the temperature history of the point contiguous to the hot-wire the
conductivity can be detennined directly From the temperature history of the point at a
fixed distance from the hot-wire the diffusivity may be computed Both procedures are
outlined in the following section
A4 Theory
The temperature at any point in an infinite solid containing a line heat source of constantshy
rate is a function of the position time from initiation the thennal conductivity of the
material and the magnitude of the source This is shown mathematically by Ingersoll et aI
(1954) The cylindrical temperature field is expressed as
T=~l- exp-x2) dx (Al)21tk x
II
In series fonn
(A2)T=~[-amp-lnp+L-L+L_ ]21tk 2 21 4middot2 63
57
where
q = Heat input per unit length of wire [W1m]
k = Thennal conductivity of the material [Wm-K]
a = Thennal diffusivity of the material [m2s]
t = Elapsed time from heat liberation [s]
r = Radial distance from line-source [m]
Ce = Eulers constant (05772157 )
The temperature change between two times tl and t2 is accurate to better than one percent if
the value of ~ is less than 016 for a point very close to the line-source
(A3)
Equation (A3) is used in this case to detennine the thennal conductivity since the
diffusivity a and the radial distance T no longer appear in the relation Therefore
knowing the temperature at two different times during the test gives the conductivity
directly given that the value of ~ remains small This is achieved by choosing a point very
near if not contiguous to the hot-wire itself In our study a graphical method is used to
detennine the conductivity If the temperature versus the natural logarithm of the time is
plotted a straight line should be seen whose slope is equal to q4nk
Once the conductivity of the material is detennined the diffusivity can be found by the
method proposed by Nix et aI (1968) The temperature at a fixed and known distance
from the hot-wire must be monitored over the time period of the test Now since ~ gt 016
the diffusivity does not drop out of Equation (A2) Rewriting Equation (A3) as
(A4)
where
~2 ~4 ~6 ]r(~)= [ -~-ln~+---+-- (A5) 2 211 4middot2 6middot3
58
therefore (A6)
Using the temperature at the fixed location as an input Equation (A6) can be solved iteratively by means of Newton-Raphson technique to find the parameter ~ and thereby
yielding the thermal diffusivity a
AS Test Apparatus
Figure A1 is a sketch of the test apparatus used to collect thermal property data This
device provides a wide range of silica densities for packed tests Each half of the apparatus
is packed separately to the same density and then pressed together sandwiching the heater
wirethermocouple assembly between them
Remove bottom plate and press together with right half
Insert heater wirethermocouple assembl)
Remove bottom plate and press together with left half
Compact both halves to same density
Fig AI Fumed Silica Test Apparatus
Prior to loading the unpacked silica into the test cylinders the mass is carefully recorded
Each test cylinder has graduated marks to allow the volume of the sample to be computed
The density is then computed from the measured mass and volume At higher densities it
59
is sometimes necessary to load and compact several times Figure A2 is a schematic of the
heater wirethermocouple assembly and the entire test facility
Switch
Ammeter
Power Source
Cylindrical Test Section
Thermocouple for Conductivity
Data Acquisition System
Thermocouple for Diffusivity
Fig A2 Fumed Silica Test Facility Schematic
The heater wire used for all tests is 30 A WG nichrome wire with a nominal resistance of 2214 Wm Both thermocouples are type T 36 A WG Once the test sample is in place
the switch is closed allowing cUITent to pass through the heater wire The heat input per
unit length of the wire is determined from
(A7)
where q = Heat input per unit length of wire [Wm]
I = The input cUITent [Amps]
R = Heater wire resistance per unit length [Wm]
60
Knowing the heat input per unit length the temperature contiguous to the heater wire and
the temperature at a fixed distance from the heater wire over the duration of the test eqs
(A3) and (A6) can be solved This yields the conductivity and diffusivity respectively
A6 Results
All results presented in this section are from tests petfonned with a material sample donated
by Cabot Corporations Cab-O-Sil Division The silica is an untreated sample EH-5 with
a bulk density of 25 Ibsft3 and a nominal particle diameter of 70 angstroms Several tests
are petfonned at various densities The thermal conductivity is determined graphically as described above while the diffusivity is determined using a Fortran code to pe~orm the
Newton-Raphson iteration also outlined in Section A4
A total of seven different bulk densities are tested Each test consists of three runs at three
different power levels The temperature history is recorded for both thermocouples
Figure A3 is a plot of the temperature for the duration of a typical test for unpacked silica
70~--~----+----r----~-----~----+----r
10001
middot middot middot o 05 Ampsmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddot o 04 Ampsi ~ i
I i I I i oo~ct 60 IIJatr-T50
1 LL~40
1 ~ 1 010 1 ltgtom
JPi i30 i 0I1 o 03 Amps 1 I I
20~--~----+----r----~-----~----+----r
-10 o 10 20 30 40 50 60 70 Time (sec)
Fig A3 Time vs Temperature for Unpacked Run
61
To graphically detennine the thennal conductivity the temperatme data must be plotted
against the natural logarithm of time Figure A4 gives this plot along with the equations
that represent linear curve-fits to the straight portion of each curve
70~----~--------+------+--------~----~----~--------+-----~
60 ~ =l-LL-~--o T ~ 86839 ~ 1376 ~(t) I
50 ---f--H-deg--tfjtshy ~ T =11108 + 97346 m(t)
40 IT_oroJ~-
30 middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotImiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotsectmiddotmiddotmiddotmiddotmiddotImiddotmiddotmiddotmiddotmiddotmiddotmiddot~middotmiddotmiddotmiddot109~~Q9 T= 18431~ + 493 ~(t) 0
~ e i i i
20~----~--------+------+--------~---------~~----+------r
05 1 15 2 25 3 35 4 45 In (time)
Fig A4 Natural Log Time vs Temperature for Unpacked Run
All three curves should yield the same conductivity for the sample The conductivity is
detennined from the following relation
k= 12R (A8)4n(slope)
Table AI gives the average conductivity for each density level This is the average for the
three input cmrents used These results are also shown graphically in Figure A5
62
Table AI A verage Fumed Silica Conductivity for Various Bulk Densities
est
1
2
3
4
5
6
7
0024
0023
0022 -~ ct 0021
~ e 002
~
0019
0018
0017
i
~i
I I I I Imiddotmiddotmiddot_middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotimiddot_middotmiddot middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotimiddot-middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot
1i111
~ ~ iii
_I_1_1_1
I I I I I middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot middotmiddotmiddotmiddotmiddotmiddotmiddotfmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddot -r-t-o-rldegoo---shy
25 3 35 4 45 5 55
Density (lbsff)
Fig AS Conductivity vs Bulk Density
From the temperature data collected from the second thennocouple the thennal diffusivity
is computed (see Section A4) This thennocouple lies 3 mm (0118 in) from the heater
63
wire The output from the diffusivity iteration is provided in Table A2 A graphical
representation is given in Figure A6
Table A2 Average Fumed Silica Diffusivity for Various Bulk Densities
Test
Average Diffusivity m2s (ft2Jhr)
1 210 x 10-7 (000813)
2 166 x 10-7 (000643)
3 159 x 10-7 (000616)
4 155 x 10-7 (000600)
5 153 x 10-7 (000592)
6 No Data Available
7 151 x 10-7 (000585)
00085 -+----+-----f----+----+----+--_+_
I
middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1 ~0008
I I I I ~
I middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotfmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot Tmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot ~ 00075
~-shyf i ~ ~ ~ i ++middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotfmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot0007 i iii
~ rn ~ ~ i i~
(jj bullbullbullbullbullbull1bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullJLbullbullbullbullbullbullbullbullbullbullj ~ 00065o ~ middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot0006
I I I 00055 -+----+-----f----+----+----f--_+_
25 3 35 4 45 5 55
Density (lbsff)
Fig AS Diffusivity vs Bulk Density
64
A7 Conclusions
The primary conclusion from this experimental study is the fact that the thennal insulating
properties of fumed silica powder increase as the bulk density of the material increases
Although this study presents a limited range of density values the trends that were
expected are seen to be true The conductivity values are expected to reach and even
surpass those of CFC-blown foams that are used in household refrigerators Further
testing is needed to provide data that supports this expectation In addition testing in this
study was strictly limited to a single variety of silica This particular type of silica is not
necessarily the best candidate for thermal insulation applications Silica powders are by
nature hydroscopic This affinity for water has adverse effects on its thermal insulating
properties However silica powders are now produced with a special treatment which
transforms the material into a hydrophobic material Therefore if these new materials
maintain the thermal properties and density trends of the hydroscopic type they become
even more preferred insulators Once again data needs to be obtained to support this
notion Fumed silica offers a competitive alternative to the existing CFC-blown foams
without the obvious environmental drawbacks It is completely inert recyclable and
reusable It also competes well when comparing cost values CFC-blown foams are
between 003 - 007 $ft2_R-Value whereas fumed silica powder are between 005 -025
$ft2-R-Value The discrepancies are close enough to merit true consideration
AS Thermal Diffusivity Newton-Raphson Iteration Source Code
program difsivty implicit none double precision condqtime(lOO)temp(lOO)guessradiusalpha
+ dif(lOO)sumavedifgcurrentmasslengthpi + density integer nikrun OPEN (2file=Oiffusivityoutlposition=rewind) OPEN (3file=Oiffusivityinposition=rewind) OPEN (4file=Oiffusivityout2position=rewind)
print Enter input current in amps readcurrent printEnter calculated conductivity in Wm K readcond print Enter thermocouple distance in meters readradius print Enter mass of sample in grams readmass print Enter compacted length of sample in em readlength print Enter number of timetemperature data points
65
c
readn 5 print enter initial quess for beta
readquess c
pi=31415927 q=currentcurrent2214 density=(mass1000)laquopi4)(003844)(lenqth100raquo
c c check to see if converqence will occur c print Enter data point l c print (time and temp with a blank separatinq the two) c readtime(1)temp(1) c call diffus(condqtime(1)temp(1)quessradiusalphaq) c printinitial q=q c if (abs(q) qt 05) then c qoto5 c endif c
do 10 i=1n read(3) time(i)temp(i)
10 continue c
print print Input Current= current print write(2) Input Current= current write (2 )
c sum=OO do 20 k=1n call diffus(condqtime(k)temp(k)quessradiusalphaq) print Diffusivity for data pointk =alpha write(2) Diffusivity for data pointk =alpha write(4) alpha dif(k)=alpha sum=sum+dif(k)
20 continue c
avedif=sumn c
print print print INPUT print Conductivity=cond Wm K print Heater Input=q Wm print Thermocouple Distance=radius m print- print OUTPUT print Sample Density=density kqm3 print Averaqe Diffusivity=avedifmiddot m2s
c write(2) write(2) INPUT write(2) Conductivity=cond Wm K write(2) Heater Input=q Wm write(2) Thermocouple Distance=radius m write (2 ) write(2) OUTPUT write(2) Sample Density=density kqm3 write(2) Averaqe Diffusivity=avedif m2s
c c
pause stop
66
end
subroutine diffus(condqtimetempguessradiusalphag) implicit none double precision condqtimetempbeta(100)radius
+ f1f2f1pf2ptempf2tempf2pggppialphaCe + signfactol integer jkmn
c Ce=5772157 pi=31415927 beta (1) =guess tol=l j=l
c c begin Newton-Raphson iteration to find beta and ultimately alpha c
while (tol gt 0001) c print betaj =beta(j)
f1=-Ce20 - log(beta(j)) flp=-l Obeta (j) f2=00 f2p=00
c c start loop to compute the summations for f2 and f2 prime
do 10 k=2162 m=k2
c this loop gives the factorial for the kth term fac=10 do 5 n=lm
fac=facn 5 continue
sign=(-1)laquok+2)2) tempf2=laquobeta(j)k)sign)(kfac) tempf2p=laquobeta(j)(k-1))sign)fac f2=f2+tempf2 f2p=f2p+tempf2p
10 continue
c c compute the value of G and G which are both functions of beta c these will be used to update beta in the Newton-Raphson iteration c where beta(n+1)= beta(n)- GG
g=laquo20picondtemp)q)-(f1+f2) gp=- (flp+f2p)
c print g=g c here we check to see if the convergence criterion suggested c by Nix is met for the initial beta chosen if not we must jump out of loop c if (j eq 1) then c if (abs(g) qt 05) then c printconvergence not satisfied c printtry a s~aller guess for beta c return c endif c endif c c update the value of beta and compute a tolerance value c that will be used to check for convergence
beta(j+1)=beta(j)-(ggp) tol=abs(beta(j+1)-beta(j))
67
j=j+1 c protect against infinite looping
if (j eq 100) then goto 101
endif repeat
c c if the iteration converges then compute the value for diffusivity
alpha=(10(40timeraquo(radiusbeta(jraquo2
c c
101 return
68
APPENDIX B ONE-DIMENSIONAL SIMULATION SOURCE CODE AND OUTPUT
B1 Source Code
CPROGRAM FrigWall--Steady-State Heat Conduction with Convective and CRadiative Heat Transfer from interior and exterior surfaces C Programmed by AM CLAUSING
LOGICAL SI DIMENSION RA(2)XNU(2)R(2)H(2)HR(2)TF(2)TW(2)DT(2) COMMON AXLWXLC(2)HC(2)T(2)XKWBETANMAXSIE(2)SIGMA
CDetermine- direction of output read and print input data NCASE=l
1 CALL DATAIN(NCASEIUOUT) NCASE=NCASE+1 QOLD=O TW(1)=T(1)+1(T(2)-T(1raquo TW(2)=T(2)-1(T(2)-T(1raquo
CCalculate wall resistance RW=XLWXKWA DO 3 N=lNMAX DO S J=12
CCalculate the radiative equivalent heat transfer coefficients HR(J)=SIGMAE(J)(T(J)2+TW(J)2)(T(J)+TW(Jraquo
C Calculate the film temperatures TF(J)=(T(J)+TW(Jraquo2
CCalculate the convective heat transfer coefficients CALL GASPT(lTF(J)RHOXMUXKCPGRBPRIER) DT(J)=ABS(TW(J)-T(Jraquo RA(J)=PRGRBXLC(J)3DT(J) IF(RA(J) LT1E9) THEN
XNU(J)=0S2RA(J)2S ELSE
XNU(J)=09RA(J) 3333 ENDIF H(J)=XNU(J)XKXLC(J) IF(HC(J) NE O) H(J)=HC(J)
CCalculate surface resistances R(J)=l(H(J)+HR(JraquoA
S CONTINUE CCalc~late total resistance heat flow rate and surface temperatures
RT=R(1)+R(2)+RW Q=(T(2)-T(1raquoRT TW(l)=T(l)+QR(l) TW(2)=T(2)-QR(2)
CCheck for convergence If solution has converged exit loop ERRQ=ABS(Q-QOLD)100Q QOLD=Q IF(ERRQLT OS) GOTO 7
3 CONTINUE 7 WRITE (IUOUT 101) Q ERRQ (H (J) HR (J) RA (J) XNU (J) TW (J) DT (J) R (J) RT
2 J=l2) 101 FORMAT( Q =F61 W10XERRQ =FS2 T12 hconvT22hradT33
2 RaT44NuTS2 TsurT62 DeltaTT72RRtotT10 [Wm2-KjT20 2 [Wm2-KjTS3 [KjT63 [Kj InsideF72F92E133F91 2 F101F91F113 OutsideF62F92E133F91F101F91F113) DO 9 J=l2 IF(HC(J) NE bull O) WRITE (IUOUT 103) J
9 CONTINUE 103 FORMAT( NOTE hconv(I1 ) was specified not calculated)
GOTO 1 END
69
C SUBROUTINE DATAIN(NCASEIUOUT) LOGICAL SI COMMON AXLWXLC(2)HC(2)T(2)XKWBETANMAXSIE(2)SIGMA DATA AXLWXKWXLCHCTENMAXSIGMA2990360245315 2 20277297 959510567E-8
CDefinition of NAM NAMELIST NAMAXLWXKWXLCHCETNMAXBETASI CHARACTER FNAME60CDATE9CTIME8 PARAMETER (IUIN=7)
CIF First Case Open Files Write Program Description and Date IF (NCASEEQ 1) THEN
WRITE (6 100) 100 FORMAT( TYPE NAME OF INPUT DATA FILE)
READ( (A) ) FNAME COpen input and output files
OPEN (7FILE=FNAME) REWIND 7
C OPEN (10FILE=Plots-FNAME) C WRITE(6122) Plots-FNAME C122 FORMAT( COMMA DELIMITED PLOTTING FILE IS A)
WRITE(6118) 118 FORMAT (T10 DIRECT OUTPUT TOT20 SCREENT36 Type 6
2 T20 OUTPUT FILET36 Type 8T20 PRINTERT36 Type 9) READ() IUOUT IF(IUOUTEQ8) THEN OPEN (8FILE=Answers-FNAME) WRITE(6120) Answers-FNAME
120 FORMAT( OUTPUT WILL BE WRITTEN IN FILE A) ENDIF CALL DATE(CDATE) CALL TIME(CTIME)
CWrite Program Description and Date WRITE(IUOUT102)CDATECTIME
102 FORMAT( Program FrigWallT60 Date A10 Version 8 August 1991T60 2 Time A9 Programmed by AMClausing) ENDIF
CRead and Write Input Data READ(IUINNAMEND=999) WRITE (IUOUT 104) NCASETXLCEXLWXKWA
104 FORMAT ( CASE NUMBER 12 2 Ambient Temperatures IK] InsideF616X OutsideF61 2 Characteristic Lengths 1m] InsideF626X OutsideF62 2 Surface Emissivities8X InsideF626XOutsideF62 Wall
Thickness 2 F63 mT27 ConductivityF63 Wm-K2x AreaF52 m2) RETURN
999 WRITE (IUOUT 199) 199 FORMAT ( ALL INPUT DATA HAS BEEN PROCESSED) 991 CLOSE(10)
IF(IUOUTEQ 8) CLOSE(8) STOP END
C SUBROUTINE GASPT(NGASTRHOXMUXKCPGRBPRIER)
C PROGRAMMED BY A M CLAUSING VERSION APRIL 1982 C PROPERTIES OF GASES IN SI UNITS(TGTO) OR ENGLISH UNITS(TLT O) C FUNCTIONAL REPRESENTATIONS USED ARE OF THE FORM Y=ATB C ARRAYS A AND B CONTAIN THE RESPECTIVE CONSTANTS C INPUT C NGAS - NGAS=l IS AIR NGAS=2 IS NITROGEN C T ---- ABSOLUTE TEMP (K) OR NEGATIVE OF ABSOLUTE TEMP (R) C OUTPUT C RHO -- DENSITY (KGM3) OR (LBMFT3)
70
C XMU -- VISCOSITY (KGM-S) OR (LBMFT-S) C XK --- THERMAL CONDUCTIVITY (WM-K) OR (BTUHR-FT-R) C CP --- SPECIFIC HEAT (JKG-K) OR (BTULBM-R) C GRB -- GBETAXNU2 (1M3-K) OR (1FT3-R) C PR --- PRANDTL NUMBER (DIMENSIONLESS) C IER -- ERROR PARAMETER C INFORMATIVE ERRORS C IER=l --- GAS NUMBER DOES NOT EXIST GAS IS ASSUMED TO BE AIR C IER=2 --- TEMPERATURE OUT OF RANGE OF PROPERTY SUBROUTINE C RESTRICTIONS C NGAS -- MUST BE l(AIR) OR 2 (NITROGEN) C T ----- T MUST LIE BETWEEN 150K AND 2100K FOR AIR AND BETWEEN C 83K AND 450K FOR NITROGEN RANGES ARE SPECIFIED WITH ARRAY R C
DIMENSION A(152)B(152)R(32) DATA A36411764E-61423E-399084178E20123 235064914E-62494E-329944985E195930 3 432491E-81239E-415534379E201137 4351618E-6221E-31031408E2084130 DATA B-1005814913800316-4639-09685 2 -999642981521962-4284023930 3 -10469389466-079-5102-0872 4 -10058058 834500239-4636-0265230 DATA R150400210083160450 IER=O IFlaquoNGASGTO) AND(NGASLT3raquo GO TO 1 IER=l NGAS=l
1 1=1 TP=T IF(TLT bullbull O) TP=-T18 IFlaquoTPLTR(lNGASraquo OR (TPGTR(3NGASraquo) IER=2 IF(TPGTR(2NGASraquoI=7 RHO=A(INGAS)TPB(INGAS) XMU=A(I+1NGAS)TPB(I+1NGAS) XK=A(I+2NGAS)TPB(I+2NGAS) CP=A(I+3NGAS)TPB(I+3NGAS) GRB=A(I+4NGAS)TPB(I+4NGAS) PR=A(I+5NGAS)TPB(I+5NGAS) IF(TGT O)RETURN RHO=RHO1602 XMU=XMUl 488 XK=XKl 731 CP=CP4187 GRB=GRB6357 RETURN END
B2 Output
Program FrigWal1 Version 8 August 1991 Programmed by AMClausing
Date Time
05-MAR-92 200227
CASE NUMBER 1 - Fresh Food Walls
Ambient Temperatures IK] Inside 2770 Outside 2940 Characteristic Lengths 1m] Inside 030 Outside 150 Surface Emissivities Inside 095 Outside 095
71
Wall Thickness 0045 m Conductivity 0027 Wm-K Area 242 m2
Q = 209 W ERRQ = 002
hconv [Wm2-K]
Inside 1 98 Outside 130
hrad [Wm2-K] 461 544
Ra
0488E+07 0459E+09
Nu
244 761
Tsur [K]
2783 2927
DeltaT [K] 13 13
RRtot
0077 0075
CASE NUMBER 2 - Fresh Food Door
Ambient Temperatures [K] Inside 2770 Outside 2940 Characteristic Lengths [m] Inside 030 Outside 150 Surface Emissivities Inside 095 Outside 095 Wall Thickness 0040 m Conductivity 0040 Wm-K Area 089 m2
Q = 117 W ERRQ = 001
hconv [Wm2-K]
Inside 218 Outside 144
hrad [Wm2-K] 463 542
Ra
0714E+07 0690E+09
Nu
269 843
Tsur [K]
2789 2921
DeltaT [K]
19 19
RRtot
0114 0113
CASE NUMBER 3 - Freezer Walls
Ambient Temperatures [K] Inside Characteristic Lengths [m] Inside Surface Emissivities Inside
2630 030 095
Wall Thickness 0056 m Conductivity 0027
Outside Outside Outside
2940 150 095
Wm-K Area 110 m2
Q = 14 3 W ERRQ = 003
hconv [Wm2-K]
Inside 226 Outside 143
hrad [Wm2-K] 397 542
Ra
0990E+07 0684E+09
Nu
292 841
Tsur [K]
2651 2921
DeltaT [K]
21 19
RRtot
0067 0061
CASE NUMBER 4 - Freezer Door
Ambient Temperatures [K] Inside 2630 Outside 2940 Characteristic Lengths [m] Inside 030 Outside 150 Surface Emissivities Inside 095 Outside 095 Wall Thickness 0040 m Conductivity 0040 Wm-K Area 034 m2
Q = 81 W ERRQ 002
hconv [Wm2-K]
Inside 259 Outside 1 64
hrad [Wm2-K] 400 538
Ra
0169E+08 0124E+10
Nu
333 967
Tsur [K]
2666 2906
DeltaT [K] 36 34
RRtot
0117 0110
72
__ ___
APPENDIX C TEST REFRIGERATOR DESCRIPTION
The test refrigerator is a White-Westinghouse model RT193MCWO 186 cubic foot
capacity top-mounted unit It is equipped with full automatic defrost The cycle time for
this unit is approximately 50 The unit also has two anti-sweat devices An electric
heater is located in the mullion region to prevent frosting between the freezer and the fresh
food compartments Also a condenser tube runs around the entire outside perimeter of the
unit embedded beneath the steel all flange Figure C1 illustrates these features
~1-- 0787 m (31)__
~ r_----------------------
1581 m
Fig CI Location of Anti-sweat Devices and Overall Dimensions of Test Refrigerator
73
Under test conditions the refrigerator and freezer are filled with milk containers full of
water These containers provide sufficient thennal mass to minimize temperature
fluctuations dming experimental runs Twenty gallons are present in the fresh food
compartment and 6 gallons are in the freezer
Figures C2 through C5 give the detailed dimensions of the fresh food compartment and
the freezer All dimensions are in millimeters and are obtained directly from the unit
Dimensions are estimated to be accurate to within plusmn 3 mm
697
762
1
305
717
Fig C2 Fresh Food Compartment Interior Dimensions
74
1127
Fig C3 Fresh Food Door
75
675
381
Fig C4 Freezer Interior Dimensions
432
Fig CS Freezer Door
76
APPENDIX D DATA ACQUISITION AND CONTROL SYSTEM
Corresponding with the construction of the experimental apparatus was the purchase and
assembly of a data acquisition and control system The system itself was designed to meet
the needs of a variety of experiments and is therefore a very flexible system
The system consists of six DC power supplies a data acquisition chassis a computer a
rack ofdigital relays and a variety of analog and digital inputs and outputs A data
acquisition and control software package orchestrates the interactions between these
components and regulates outgoing signals as well as providing data storage
External signals enter the system through a Keithley 500P data acquisition chassis These
signals consist of voltage and current measurements from the power supplies as well as
thermocouple voltages At present a total of ninety-six thermocouple inputs are available
with an optimal resolution of +0012 degrees C The addition of more thermocouple input
boards could expand the capability to 128 inputs Also special boards can be installed to
allow strain gauge thermistor digital or other standard data acquisition functions The
Keithley chassis can contain a total of nine interface boards and its l~bit AID conversion
allows for very high resolution
The six DC power supplies consist of two Hewlett Packard and four Sorensens with a
combined power of 7560 watts The Sorensens are rated at 0-150 volts at a maximum of
12 amps while the Hewlett Packards produce 0-60 volts at a maximum of 3 amps All of
the power supplies are computer-controlled however the Sorensens may be operated
manually ifdesired Voltage measurements from the power supplies are fed into the
Keithley acquisition chassis and are then routed to the computer A voltage from the
computer is buffered and fed into the control circuits of the power supplies This voltage
completes the loop and controls the output voltage of the power supplies The software is
responsible for reading the output voltage of the power supplies comparing it with the
intended setpoint and adjusting the control voltage as needed This arrangement allows the
user to vary the output voltage of the power supplies from within a program Computershy
controlled safety relays are in place to disconnect the power supplies should they stray too
far from the intended voltage setpoint Fig D1 displays the system
77
Thermocouple and Voltage Inputs
r
Computer Data Acquisition Chasis Intaface
00 Voltage and 1 r Current
Measurement
Computer
I I
Analog Control Signal
Digital Oulput Signals 5 6
Power Supply 4 Relay Rack
Power Supply 3 00000001 Power Supply 2
Buffered Analog100000001 Power Supply 1 Control Signal
1 2 3 4 5 6 - I
I00 00 )0 po po po
Ir Digital Outputs
Analog Outputs
Fig DI Data Acquisition and Control System
78
APPENDIX E EXPERIMENTAL RAW DATA AND PLOTS
E1 Temperature Profile Plots From Fixed Thermocouples
In this appendix the remaining tests for the fixed thennocouple testing presented in Section
41 are provided Figures E1 and E2 give the results from the fresh food compartment
and Figures E3 and E4 give the results from the freezer Notice the outdoor and interior
ambient temperatures are not the same as the two tests presented in Section 41
191
Run 2 ttl ~ i i
middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot
middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot-imiddotmiddot
TWall
middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotlmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot
-
Outdoor Ambient =210 degC Fresh Food Ambient =375 degC
-] _ Door ProfUe i -il- 0 Wall Profile
i 19
$-- - Tdo = 19078 - 001326x
l~l ~~i 189 i i a m
0 i -m-
i 188 middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot
187 ~ middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot 5 = 18989 - O02024x 1
F 186
~bullbullbullbullbullbullbullmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot185 i i
184 0 5 10 15 20 25
x (mm)
Fig E1 Steel Skin Temperature Plot for Fresh Food Compartment (Run 2)
79
191
19
189
a ~
i 188
187
5F
186
185
184 0
Run 3 I --D - Door Profile
middotmiddotmiddotmiddotmiddotmiddotmiddotmiddot-middotmiddotmiddotmiddot~middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotimiddotmiddot-middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddot 0 Wall Profile
i - i - - Tdo =19053 - 001384x or
=c-=r=-~-= 1 11=
~ n - 189S 001998 --t-shy-~~-
5 10 15 20 25
x (mm)
Fig E2 Steel Skin Temperature Plot for Fresh Food Compartment
186
184
182
- ~- 18
178
~ 176
174
172 0
(Run 3)
Run 2 l --0 - Door Profile
middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot~middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotdrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotf 0 Wall Profile - 1- - middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot--m
- - T =18544 - 002398x i - i door rb
~i
i bullbullbulli _ bull imiddot
~ I TWall =18182 - 003542x tmiddotmiddotmiddotmiddot middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotlmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot
~ n~l l
5 10 15 20 25
x (mm)
Fig E3 Steel Skin Temperature Plot for Freezer (Run 2)
80
--a 0
I5F
186
184
182
18
178
176
174
172
Run 3 I --0 - Door Profile
middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotCmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotl 0 ~a1l Profile
ttl __ OJ 1 1 middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotfmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotlmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot -shy - Td = 18411 - 002272x ibullbullbullbullbullbullbull-bullbullbullbullbullbullbullbullbulli
oor ~
rp bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbull bull 11_1
I I middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotimiddotmiddotmiddotmiddot middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotImiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot
~ _l
Outdoor Ambient =208 degc Freezer Ambient = -93 degc
0 5 10 15 20 25
x (mm)
Fig E4 Steel Skin Temperature Plot for Freezer (Run 3)
E2 Thermopile Data Reduction
The data from the thennopile tests consist of an output voltage (mV) measured with a
Keithley multimeter which has a resolution of 1 m V The procedure required to translate
this voltage into a temperature difference follows
1 Read the output voltage in millivolts
2 Detennine the average skin temperature from fixed thennocouple data
3 Use the reference table and the average skin temperature to determine the conversion factor in Vrc
4 Convert to temperature difference as follows
1T = ____o_utpu_t_vo_l_tag-e___
ofjunctions x conversion factor
81
Table EI Thermopile Raw Data
ffOutput fzOutput ff Ave Skin Temp fz Ave Skin Temp mV mV CC CC
Roo wall door wall door wall door wall door
1 0052 0048 0045 0050 189 191 177 183
2 0054 0052 0046 0048 187 189 176 182
3 0056 0053 0046 0051 186 188 175 181 ff Conv Factor fz Conv Factor ff AT fzAT
Ilvrc Ilvre CC CC
Roo wall door wall door wall door wall door
1 40165 40181 40067 40116 026 024 037 041
2 40148 40165 40058 40107 027 026 038 040
3 40140 40157 40050 40099 027 026 038 040
Average Temperature Difference 0267 0377 0253 0403
from Thermocouple Reference Tables Based on the IPTS-68 US Dept of Commerce
E3 Experimental Determination of qwall and qdoor Details
The four heat fluxes are calculated using
-k M (El)q - m Ax
For 05 carbon cold rolled steel km =540 Wm K (312 Btuhr-ft-OF) Also Ax = OOlm (039 in) for all computations
0267degC 2 qwallff = 54 Wm-K 001 m = 14418 Wm
_ 0377 degc _ 2 qwallfz - 54 Wm-K 001 m - 20358 Wm
0~3~ 2 qdoorff =54 Wm-K 001 m =13662 Wm
82
0403degC 2 qdoorfz = 54 Wm-K 001 m = 21762 Wm
Compute the heat transfer rate according to Equation (B2)
q =qA=qhP (B2)
Where A is the cross sectional area of the steel casing that is perpendicular to the direction
of heat flow The area is the product of the steel skin thickness b and the total perimeter of
the compartment opening which is exposed to the room environment P Perimeter
definitions
Pwallff = llm + 076m +llm = 296 m
roJ D Pwallfz =O4lm + 076m + O4lm =l58 m
I ] I ~I Pdoorf( = llm + 076m + llm + 076m = 372 m
Pdoorfz =076m + O4lm + 076m + 041m =234 m
83
qwallff =(14418 Wm2)(65e-4 m)(296 m) =277 W
qwallfz =(20358 Wm2)(65e-4 m)(158 m) =209 W
qdoorff =(13662 Wm2)(65e-4 m)(372 m) =330 W
qdoorfz =(21762 Wm2)(65e-4 m)(234 m) =331 W
E4 Temperature Profile Plots From Mullion Data (Heater oro
The following plots are from the remaining runs for the mullion analysis presented in
Section 45 All data is taken from the exact center of the mullion
131
13 middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot-tmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotjmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotlmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot9middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotlmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot6middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddot T 11 f =12383 + 0019929x iii mu z
129 ~ middotImiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot[middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddota ~
i 128 middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot4middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot-j-middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotfmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotfmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot
127e ~
126 ~~~=H~~-~=HmiddotrI~ ++~11 Room Ambient =2250 degC125
1 1 i Fresh Ambient =515 degC iii i i Freezer Ambient =-603 degC
124
1 10
Fig ES Mullion Temperature Profile Run 2 (Heater Off)
Run 2
2 3 4 5 6 7 8 9
TIC
84
146
145
a 144 ~
i 143
5 ~ 142
141
Run 3 9 0
---r-r--deg-r-ideg-t-9--rshyiii ltD T 11 ff = 15173 - OOI71x mu bull
middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotfmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotImiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot6middotmiddot
1Tmull~fz =14062 + J0158211x JLt 1
Q 1 1 1 middotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1-middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddoti-middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotimiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotoot-middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot-I-bullbullbull~bullbullbullbullbullbullbullbullbullbullbull
iii middotiiimiddot-j Room
1Am~t = 21~1 degC
iii i 1 Fresh Ambient = 563 degC 1 1 1 1 1 Freezer Ambient = -153 degC
14~---+--~----r---+---~---+--~----r---+-
1 2 3 4 5 6 7 8 9
TIC I
Fig E6 Mullion Temperature Profile Run 3 (Heater Off)
127
126
125 a ~
i 124
123 e ~
122
121
12
1
Fig E7
i i CD middotmiddotmiddotmiddot----middotmiddot-r--middot---middotmiddotmiddotmiddotmiddotmiddot-lmiddot--------middotmiddotmiddotmiddotl-middotmiddot---middotmiddotmiddotmiddot---r---middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1middotmiddotmiddotmiddotmiddot---middotmiddot---middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot-r----middot1__ _-
I I I T mulIff = 1321 - 001532x middotmiddotmiddotmiddot------middott--------------tmiddotmiddot----middot----middotmiddot-1------middotmiddotmiddotmiddotmiddotmiddot---jmiddot-----middotmiddotmiddotmiddotmiddotmiddotmiddotmiddot-lmiddotmiddotmiddot---middotmiddotmiddot-----tmiddotmiddotmiddotmiddotmiddot--middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddot-----middotmiddotmiddot6middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot
I cent I I I I -~~~~-ro-Tr-
r-middotmiddotmiddotmiddotrTTr-middotrmiddotrmiddotrmiddot middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddott middotmiddotmiddottmiddotmiddot1middotmiddotbullbullbullbull fmiddotbullbullbullbullbullbullbullmiddot-fbullbullbullbullbullbullbullmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot
II Room Ambil =21~3 degC iii i i Fresh Ambient =551 degc iii i i Freezer Ambient = -681 degC
2 3 4 5 6 7 8 9 10
TIC I
Mullion Temperature Profile Run 4 (Heater Off)
85
10
111
iii i i 11
Fttul5
T mu
=J=~[rr~tl=rI=109
a ~ 108 -t-t-t-i~FFl~i~~
+-0amp_- -+_bullbullbullbullbullbullbullbull+ - bullbullbull 107 11 f ~ 10325 + 0021893x 1 1 1 ji
5 bull Z iii
------~-~-----~---i --L--l ---_l__ ---L-----_shy106 ~
105 -t---i--+-+-+-middot++-I-shyL1LLL Room Ambient = 2177 C104 iii i i Fresh Ambient =448 degC
Freezer Ambient = -644 degC 103
1 2 3 4 5 6 7 8 9 10
TIC
Fig E8 Mullion Temperature Profile Run 5 (Heater Off)
86
34
33 1 1 1 1 1 1 1 1------I---------middotmiddot--+middotmiddotmiddotmiddot------middottmiddot-------middotmiddotmiddotmiddottmiddot----------middotmiddotmiddot---middot---middot----tmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot---middotmiddott--middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot(middotmiddotmiddotmiddotmiddot--
32 11 f =1 2859 ~ OI~X j
Till ff =133013 j - 007124x mu
31
a ~ 30
i 5 ~
29
28
27
26
Tmullfz = 26944 + 014842x
mu t-tr l
25 middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotjmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotjmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotlmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1middot ~ u~ ~it
24 lllti1 ~ i i ~ i
0 Lower Limit
23
0 1 2 3 4 5 6 7 8 9 10
ES Temperature Profile Plots From Mullion Data (Heater On)
The following are the remaining plots from the mullion heater analysis presented in Section
46
TIC I
Fig E9 Mullion Temperature Profile Run 2 (CenterHeater On)
Run 2
T muz
1
87
l----+
29
middotmiddotmiddotgtmiddotmiddoti middot 0 upper Limit 28 Run 1
I
middotmiddotI o
Tmullfz
T muo
LL~4cb 0 Lower Limit27
middot~+ImiddotmiddotmiddotImiddotmiddotmiddottr9middotdJmiddotmiddotmiddotmiddot 26
t T = 29465 008022xmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddot1middotmiddotmiddotmiddotTmiddotmiddotmiddotmiddot[middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1middot mullffa 25~
i 24 =24837+ 013186x middotlmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot+middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotimiddotmiddotmiddotmiddotmiddotmiddotmiddotlmiddotmiddotmiddotmiddotmiddotmiddot iii i i
i _ Jbullbullbullbullbullbullbullbullbullbullbullbullbulli l _l ii 23
e 22~ 21 +I~=tt=l=fit
L~LLL Tm~llff = 23856 005858x20 11 f = 1803 + 02243x z -rmiddotmiddotmiddotmiddot1middot middotmiddot middotmiddot 1middotmiddotmiddotmiddotmiddotTmiddotmiddot middot-rmiddot19
18
0 1 2 3 4 5 6 7 8 9 10
TIC
35
34
33
32
a ~ 31
I ~
30
29
28
27
26
25
24
Fig EI0
---bull---i----bullbullmiddotmiddotmiddotmiddot--~--------middotmiddot-+------ j bullbullbullbull ---bullbullbullbull -i--__---
T 11 f =30063 + OI~x 1 T i 134 196 i
0068 1 38
muz tmiddotmiddot Ilff=middot bull x ltP lt1gt mu
=t=H=t+t=R=t= F-6~I-i~E
Tmullfz = 28103 + 014486x 1middot++middot1middot1
middotmiddotmiddot--middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotimiddotmiddotmiddotmiddotmiddotmiddotmiddot-middotmiddotmiddotmiddotmiddot+middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotbullbullmiddotmiddotmiddot-middotmiddotimiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot~middotmiddot
111111 0 Upper Limit iii iii 0 Lower Limit
0 1 2 3 4 5 6 7 8 9 10
TIC
Mullion Temperature Profile Run 3 (CenterHeater On)
Fig Ell Mullion Temperature Profile Run 1 (LeftHeater On)
88
a
29
28
27
26
25~
i 24
23 e
22~ 21
20
19
18
Fig E12
i l middot middotmiddotmiddotmiddotlmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot+ 0 Upper Limit T 11 f =24474 + 011288x i imu bull z o Lower Limit
=tplusmntplusmnfrplusmnplusmnplusmn ~ I I I I Tmull ff ~ 28793 - o0784x
middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddott----middot------middotmiddotimiddot----middot-middotmiddot--middot-~-middotmiddotmiddot--middot----middotmiddot)middot
=ii=t=1=P-Ltplusmnt iii i T = 25599 - 00689xIfmiddotTTTmiddotmiddotrmiddot ~Ullff iii
T l1f =20552 + 01676x i~~imiddotimiddotmiddot
==~LL L LLLLL i i 1 ~ 1 ~
0 1 2 3 4 5 6 7 8 9 10
TIC I
Mullion Temperature Profile Run 2 (LeftlHeater On)
33 iii i i
-middot--middot(---middotmiddot--middotmiddot--middotmiddot+---middot-middotmiddotmiddotmiddot-middotmiddotmiddot~-middot--middot-------middoti---middot------~ o Upper Limit 32 Run 3
t bullbullbull +
Tm~llfz
T mu
1 1 1 1 1 o Lower Limit ~~31
=2713 ~ 0113~x j11Li30
a T ulff =30658 - 006506x 29~
IktlJ2~Li 28
27 e
26 =l=tt=tmiddotmiddottmiddott+~middot+=t=~ middotmiddot jmiddotjmiddottmiddottmiddotjmiddot T = 28288 - 00603x
iii i mullff 24
25
middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotQmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot+middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot~middotmiddotmiddot middotmiddotmiddotmiddotmiddotmiddotmiddotmiddot~middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot+middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot 11 fz = 2377 ~ 01788x IL11123 i i
22
0 1 2 3 4 5 6 7 8 9 10
TIC I
Fig E13 Mullion Temperature Profile Run 3 (LeftHeater On)
89
31
30
29
ltP ~u
J
1 T
-~Lti=t~-t--t i~+--Ij Tmu1lff =31473 middot005222x 28
1 1 1middot 1 l i l i bullbullbullbullbullbullbull__ bullbullbullbull_ bullbullbullbullbullbullbull~_bullbullbullbullbullbullbullbullbulla bullbullbullbullbullbullbullbullbullbullbull a 27
~ Tm~llfz = 26857 + 01734x _~__+_+II i
26
bullmiddotmiddotbullbullbullmiddotmiddotbullibullbullbullbullbullbullbullbullbullbullbullmiddotmiddotmiddotbullbullbullbullbullbullbullbullmiddotmiddotmiddotmiddot bullbullbullbullbullbullbullbullbull-i-~-i-ii25
JJ$~L-f$9 5 24
~ 23 middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotlmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot+middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot~middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot+middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1-middotmiddot T mllff =25622 bull 002~7X c-bullbullbullbullbullbullbullbullbullbullbullbull+ ~~ 22 rp 1 1 i i 1 1 1
21 = 19464 + 02548 jmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddott Upper Limitmullfz xii 0
4-bullbullbullbullbullbullbullbullbullbullbullbullimiddotmiddotmiddotbullbullbullbullbullbullmiddotf20 i 1 ~ 1
19
0 1 2 3 4 5 6 7 8 9 10
TIC I
Fig E14 Mullion Temperature Profile Run I (RightHeater On)
33 i
middotmiddotmiddotmiddotlaquomiddotmiddotmiddotmiddot------------------------------- c--------middotmiddotmiddot-middot-----------middotmiddotmiddot---middotmiddot--------l-----middot-----I-----32
= 2757 + 017006x ILLJ1
a
31
30
29~
i 28
Run2
TmulIfz
T~ulIfz ~
-~t=ii~Ii~~~~ i
27 middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot9-middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotT~~middotmiddotmiddotmiddotmiddot2s944-middot~middotmiddotO0278~middotmiddote 26~ r~rrTt+rr25
24 2320~ + O~S4x middotmiddotlmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotjmiddot ~ u~ L~t 23 middotmiddotmiddotmiddotmiddotmiddotmiddotmiddot~middotmiddotmiddotmiddotmiddotmiddotmiddot+middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot+middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot+middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotImiddotmiddotj 0 Lower Limit
22
0 1 2 3 4 5 6 7 8 9 10
TIC I
Fig EIS Mullion Temperature Profile Run 2 (RightlHeater On)
90
33 i i ~ _______ _ _~____ __ __-i--bullbullbullbullbullbullbullbull-t------ -- uu__~ ~ --~32
=1268931+ 0~4~14X 111131
30
a 29~
I 28
Run3
Tmullfz
i t+ I T
m
mnplusmn~~27 6 i 1 i 1 +++ T mullff =28912 - 002938x 26~ +middotmiddot++Imiddotjmiddott-25
= 22996 + 02312x 1middotmiddot+ 24
~~~~L lL1 0 ~23 ill 0 22
0 1 2 3 4 5 6 7 8 9 10
TIC
Fig E16 Mullion Temperature Profile Run 3 (RightHeater On)
91
APPENDIX F NUMERICAL SIMULATION EQUATIONS AND CODE
F1 Finite-Difference Equations
Figure Fl is a generic resistor network that is used as a base for all the finite-difference
equations The general fonn is
(Fl)
r----II ij+l
J
i j-l L ______--J
Fig F1 Generic Nodal Resistor Network
This makes it easy to simply plug in the different resistors for the different regions of the
section There are twelve resistors total The following table summarizes the resistors
needed to complete the model
Table F1 Model Resistors
Description Resistance [CIW]
Interior insulation x direction Rl= dx dymiddotkinsmiddotb
92
dyInterior insulation y direction R2= dx-kins-b
dySteel parallel with insulation y direction R3= km-dm-b + kins-(dx -dm)
dxR=Steel parallel with insulation x direction km-dm-b + kins-(dy -dm)
dyRs=Plastic parallel with insulation y direction
kp-dp-b + kins-(dx -dp)
dxPlastic parallel with insulation x direction R6= kp-dp-b + kins-(dy -dp)
heffa- (~- dm) + kinsSteel to exterior x direction R7= 2
heffo-kins-dy-b
heffa- (dY - dm) + kinsSteel to exterior y direction R - 28shyheffo-kins-dx-b
hefti- (dY _dm) + kinsSteel to interior y direction R9= 2
heffi-kins-dx-b
hefti- (~- dp) + kinsPlastic to interior x direction RIO= 2
heffi-kins-dy-b
Rll = hefti- (dJ -dP) + kinsPlastic to interior y direction
heffi-kins-dx-b
93
Steel skinplastic skin interface
2middotkmmiddotdmmiddotkpmiddotdpmiddotdxR12=----------------------~~----------------
2middotkmmiddotdmmiddotkpmiddotdpmiddotbmiddot(dy -dp) + (kpmiddotdp + kmmiddotdm)middotbmiddotdx2
F2 Wall Simulation Source Code
Program FiniteDiff
c This program simulates the conductive heat transfer through the wall section c of the refrigerator near the door gasket using Guass-Siedel iteration c The program allows for flexibility in the geometry and material properties c The program is a steady-state model
cVariable Definitions
c km = conductivity of the outer metal skin (Wm-K) c kins = conductivity of the polyurethane foam insulation (Wm-K) c kp conductivity of the inner plastic skin (Wm-K) c dm = thickness of the metal skin (mm) c dp = thickness of the plastic skin (mm) c b = depth of the section (m) c heffo = effective heat transfer coefficient on outside surfaces (Wm2-K) c heffi = effective heat transfer coefficient on inside surfaces (Wm2-K) c sl width of wall inSUlation (mm) c s2 length of wall section (mm) c s3 seal indentation (mm) c s4 seal width (mm) c s5 distance metal skin travels into cabinet (mm) c s6 distance platic skin travels out of cabinet (mm) c ns = number of nodes corresponding to the s regions above c rs = network resistors (m-eW) c i = integer values of distance along the x axis c j = integer values of distance along the y axis c imax maximum integer value in x direction c jmax maximum integer value in y direction c iter total number of iterations to converge c loop convergence flag c Qinl Heat flux per unit length across the outer boundary (Wm) c Qin2 Heat flux per unit length across the inner boundary (Wm) c Qdif Qinl - Qin2 (Wm) c Qpdif = percent difference between the heat fluxes Qinl and Qin2 c Ti Inside ambient temperature (e) c To = Outside ambient temperature (e)
cDeclare Variables
INTEGER nln2n3n4n5n6ijloopimaxjmaxiter INTEGER clflaglflag2 REAL kmkinskpdmdpdxdyheffoheffi REAL TiToQdifQpdifQinlQin2 REAL sls2s3s4s5s6lenoutlenin REAL rlr2r3r4r5r6r7r8r9rlOrllr12 REAL T(-1lOl-1lOl)bqlDsumlsum2 REAL Qm(lOl)qfluxm(lOl)fluxo(OlOl)fluxi(OlOl)
94
REAL fluxcen(0101)pfluxcen(0101)pfluxo(0101) REAL pfluxi(0101)pmaxdifoneDtolaq2Dqedge1
OPEN (10file-2Dcode(v11)out1position-rewind) OPEN (11file-2Dcode(v11)out2position=rewind)
cTest Parameters
c thermal conductivity of the outer metal skin (Wm K) km-540
c thermal conductivity of the wall insulation (Wm K) kins=0021
c thermal conductivity of the inner plastic skin (Wm K) kp=015
c thickness of the metal skin (mm) dm=065
c thickness of the plastic skin (mm) dp=25
c effective heat transfer coefficient on outside surfaces (Wm2-K) heffo=681
c effective heat transfer coefficient on inside surfaces (Wm2-K) heffi=610
c width of section (mm) sl=450
c length of section (mm) s2=2000
c depth of the section (m) b=10
c inside ambient temperature (C) Ti=95
c outside ambient temperature (C) To=210
c unit conversions dm=dm1000 dp=dp1000 sl=sl1000 s2=s21000
c specify 1-dimensional tolerance (t) oneDtol=30
cMesh Parameters
c specify the following nodal mesh parameters n1=20 n2=80 n3=1 n4=9 n5=10
c various mesh dimensions dx=sln1 dy=s2n2 s3=n3dx s4=n4dx s5=n5dx s6=sl-s5-dx n6=s6dx imax=n1-1 jmax=n2-1
cInitialize temperature matrix
DO 10 j=-1jmax+1 DO 20 i=-1imax+1 T(ij)=Ti
95
20 CONTINUE 10 CONTINUE
DO 30 j=Ojmax T(-Ij)=To
30 CONTINUE
DO 40 i=0n3 T(i-I)=To
40 CONTINUE
DO 50 j=Ojmax T(imax+lj)=Ti
50 CONTINUE
DO 60 i=n3+n4+1imax T(i-I)=Ti
60 CONTINUE
cResistors [m-CW]
c interior insulation x direction rl=dx(kinsdy)
c interior insulation y direction r2=dy(kinsdx)
c metalinsulation y direction r3=dy(kmdm+kins(dx-dm))
c metalinsulation x direction r4=dx(kmdm+kins(dy-dm))
c plasticinsulation y direction r5=dy(kpdp+kins(dx-dp))
c plasticinsulation x direction r6s dx(kpdp+kins(dy-dp))
c metal to exterior x direction r7=(heffolaquodx2)-dm)+kins)(heffokinsdy)
c metal to exterior y direction rB=(heffo laquody2)-dm) +kins)(heffokinsdx)
c metal to interior y direction r9=(heffilaquody2)-dm)+kins)(heffikinsdx)
c plastic to interior x direction rl0=(heffilaquodx2)-dp)+kins)(heffikinsdy)
c plastic to interior y direction rll=(heffilaquody2)-dp)+kins)(heffikinsdx)
c metalplastic interface rI2=(2kmdmkpdpdx)(2kmdmkpdp(dy-dp) + (kpdp+km dm)dxdx)
cxxxxxGuass-Siedel Iterationxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx loop=1 iter=1 DO WHILE (loop eq 1)
c Equations for row 0 i=O j=O CALL sseqn(Tr4r7r3rBijimaxjmax)
DO 70 i=ln3 j=O CALL sseqn(Tr4r4r2rBijimaxjmax)
70 CONTINUE
DO 75 i=n3+1n5-1
96
j=O IF (i le n3+n4) THEN
CALL sseqn(Tr4r4r21e20ijimaxjmax) ELSE
CALL sseqn(Tr4r4r2r9ijimaxjmax) ENDIF
75 CONTINUE
i=n5 j-O IF (i le n3+n4) THEN
CALL sseqn(Tr12r4r21e20ijimaxjmax) ELSE
CALL sseqn(Tr12r4r2r9ijimaxjmax) ENDIF
i=n5+1 j=O IF (i le n3+n4) THEN
CALL sseqn(Tr6r12r21e20ijimaxjmax) ELSE
CALL sseqn(Tr6r12r2rllijimaxjmax) ENDIF
DO 80 i=n5+2imax-l j=O IF (i le n3+n4) then
CALL sseqn(Tr6r6r21Oe20ijimaxjmax) ELSE
CALL sseqn(Tr6r6r2rllijimaxjmax) ENDIF
80 CONTINUE
i=imax j=O CALL sseqn(TrlOr6r5rllijimaxjmax)
c Equations for rows 1 thru jmax-l DO 90 j=ljmax-l
i=O CALL sseqn(Tr1r7r3r3ijimaxjmax)
DO 100 i=1imax-1 CALL sseqn(Tr1r1r2r2ijimaxjmax)
100 CONTINUE
i=imax CALL sseqn(Tr10r1r5r5ijimaxjmax)
90 CONTINUE
c Equations for row jmax j=jmax i=O CALL sseqn(Tr1r710e20r3ijimaxjmax)
DO 110 i=1imax-1 j=jmax CALL sseqn(Tr1r110e20r2ijimaxjmax)
110 CONTINUE
i=imax j=jmax CALL sseqn(Tr10r11Oe20r2ijimaxjmax)
97
c c c
Compute the difference in heat flux crossing the outer boundary and crossing the inner boundaryr ideally the difference should be zero
CALL balance(TToTidxdyn3n4imaxjmaxQdifQpdif c QinlQin2r7r9r8rlOrllb)
c Update loop variables iter-iter+l
c Convergence criterium IF (Qpdif le 20) then
loop-O ENDIF IF (iter eq 10000) THEN loop=O write(lO) Solution did not converge
ENDIF
END DO cxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
cHeat Transfer Calculations
c Compute 10 heat flux through wall CALL oneD (ToTiheffoheffikmkinskpdmdpslqlD)
c Compute the flux thru wall at each node on the c outside and inside walls [Wm2) Also the flux c in the x-direction across the center line of the c section
cl-int(nl2) fluxcen(0)=(1(r4dy))(T(cl0)-T(cl+l0)) fluxo(0)=(1(r7dy))(To-T(00)) fluxi(O)=(l(rlOdy))(T(imaxO)-Ti) DO 112 j=ljmax
fluxcen(j)=(l(rldy))(T(clj)-T(cl+lj)) fluxo(j)=(1(r7dy))(To-T(0j)) flumiddotxi (j) =(1 (rlOdy)) (T (imax j)-Ti)
112 CONTINUE
c Determine the percent of steady-state 10 losses DO 113 j=Ojmax
pfluxcen(j)=(fluxcen(j)qlD) 100 pfluxo(j)=(fluxo(j)qlD)lOO pfluxi(j)=(fluxi(j)qlD)lOO
113 CONTINUE
c Determine where the heat transfer becomes 10 c based on a criticle percentage
flagl=O DO 114 j=O jmax
a=abs(pfluxcen(j)-lOOO) IF (j ne jmax) THEN
IF (a le oneDtol) THEN jstar=j
ENDIF ELSE
IF (a le oneDtol) THEN jstar=j
ELSE flagl=l
ENDIF ENDIF
98
114 CONTINUE
c Determine the edge loss by subtracting the 10 heat c transfer from the heat transfer in the 20 region c across the centerline
flag2=0 IF (flagl eq 0) THEN
q2D=00 DO 115 j=O jstar
q2D-q2D+fluxcen(j) 115 CONTINUE
qedgel=q2D-qlD ELSE
flag2=1 ENDIF
c 10 heat flux along metal skin under the seal into c the cabinet [Wm2J Fluxes for all metal nodes are c computed as well as an average flux The flux from c node (n3+l0) to node (n3+20) is given as qlDm(l) c and so on Assume the temperature of the metal skin c is the temperature of the node at that location
suml=OO sum2=00 DO 119 i=n3+1n3+n4-l
Qm(i)=laquokmdmb)dx)(T(i0)-T(i+10raquo qfluxm(i)=(kmdx)(T(iO)-T(i+lOraquo suml=suml+Qm(i) sum2=sum2+qfluxm(i)
119 CONTINUE pmaxdif=laquoQm(n3+n4-l)-Qm(n3+1raquoQm(n3+lraquo100 qedge2-qfluxm(cl)
cOutput
c Output nodal temperatures to separate file DO 120 j=Ojmax
write(ll) (T(ij)i=Oimax) 120 CONTINUE
c Output flux info to a different file write(10) INPUT PARAMETERS write(lO) write (10 ) Section Dimensions (mm) write(lO) Width sl1000 write (10 ) Length s21000 write(10) Depth blOOO write(10) Steel skin thickness dmlOOO write(lO) Plastic skin thickness dplOOO write(lO) write(10) Mesh Geometry write(10) dx dxlOOO write(lO) dy dylOOO write(lO) Number nodes in x-direction n1 write(lO) Number nodes in y-direction n2 write(lO) Number of steel skin nodes write(lO) (including corner 00) n5+l write(10) Steel nodes under the seal n3+1 ton3+n4 write(10) write(lO) Steel skin conductivity (Wm K) km write(lO) Foam insulation conductivity (Wm K) kins write(lO) Plastic skin conductivity (Wm K) kp write(lO) Outside h (Wm2 K) heffo write(lO) Inside h (Wm2 K) heffi
99
write(10) Outside Temp (C) To write(10) Inside Temp (C) Ti write(10) write (10 ) write(10) write(10) OUPUT PARAMETERS write (10 ) write(10) Number of iterations iter write(10) write(10) Heat Transfer for the Section write(10) OVerall Heat Transfer (W) Qin1 write(10) 10 Heat Flux Thru Wall (Wm2) q1D write (10 ) write(10) Heat Transfer Along Metal Skin Under Seal write(10) node to node qm[Wm2J Qm[WJ DO 135 i=n3+1n3+n4-1
write(10) i i+1 qfluxm(i) Qm(i) 135 CONTINUE
write (10 ) Maximum difference () abs (pmaxdif) write(10) IF (flag2 eq 1) THEN
write(10) The mesh does not extend far enough write(10) in the y-direction to reach 10 heat write(10) transfer for the specified tolerance write(10) ofoneDtol
ELSE write (10 ) Edge loss computed from qe=q2D-q1D qedge1 write (10 ) write(10) Edge loss computed directly from write(10) steel skin ~T at centerline qedge2
ENDIF write (10 ) write (10 ) write(10) Heat fluxes in thru the section write(10) along the centerline [Wm2J write (10 ) write(10) j flux 10 DO 136 j=Ojmax
write(10) j fluxcen(j) pfluxcen(j) 136 CONTINUE
PAUSE STOP END
C
SUBROUTINE sseqn (Trplusirminusirplusjrminusj i jimax jmax)
c This subroutine computes the temperature at node (ij) c given the temperatures of the surrounding nodes and c the resistances leading to these nodes
INTEGER ijimaxjmax REAL T(-1101-1101)rplusirminusirplusjrminusj REAL c1c2c3c4c5
c1=1rplusi c2=1rminusi c3=1rplusj c4=1rminusj c5=c1+c2+c3+c4
T(ij)=(1c5)(c1T(i+1j)+c2T(i-1j)+c3T(ij+1)+c4T(ij-1raquo
100
RETURN END
C
SUBROUTINE balance(TToTidxdyn3n4imaxjmaxQdifQpdif c Qin1Qin2r7r8r9r10r11b)
c This subroutine computes the steady-state heat balance c for the cross-section
INTEGER imaxjmaxijn3n4 REAL T(-1101-1101)TlToQin1Qin2dydx REAL r7r8r9r10r11b
c Compute the heat entering Qin1 [Wj Qin1=00 DO 10 jOjmax
Qin1=Qin1+(b(r7))(To-T(0j)) 10 CONTINUE
DO 20 i=0n3 Qin1=Qin1+(b(r8))(To-T(i0))
20 CONTINUE
c Compute the heat leaving Qin2 [Wj Qin2=00 DO 30 j=Ojmax
Qin2=Qin2+(b(r10))(T(imaxj)-Ti) 30 CONTINUE
DO 40 i=n3+n4+1imax IF (i le nS) then
Qin2=Qin2+(b(r9))(T(i0)-Ti) ELSE
Qin2=Qin2+(b(r11))(T(i0)-Ti) ENDIF
40 CONTINUE
c Compute the absolute difference in heat fluxes [Wj Qdif=abs(Qin2-Qin1)
c Compute the percent difference in the heat transfers [Wj Qpdif=(QdifQin1) 100
RETURN END
C
SUBROUTINE oneD (ToTiheffoheffikmkinskpdmdpslqlD)
c This subroutine compute the one-dimensional c heat flux through the section wall
INTEGER i REAL ToTiheffoheffikmkinskpdmdpsl REAL q1DReqdins
dins=sl-dm~dp
Req=(lheffo) + (dmkm) + (dinskins) +(dpkp)+(lheffi) q1D=(To-Ti)Req
RETURN END
101
F3 Fresh Food Wan Simulation Output
INPUT PARAMETERS
Section Dimensions (mm) Width 4500 Length 2000 Depth 1000 Steel skin thickness 6500 Plastic skin thickness 2500
Mesh Geometry dx 2250 dy 2500 Number nodes in x-direction 20 Number nodes in y-direction 80 Number of steel skin nodes (including corner 00) 11 Steel nodes under the seal 2 to 10
Steel skin conductivity (Wm K) 5400 Foam insulation conductivity (Wm K) 21000E-02 Plastic skin conductivity (Wm K) 1500 Outside h (Wm2 K) 6810 Inside h (Wm2 K) 6100 Outside Temp (C) 2100 Inside Temp (C) 4000
OUPUT PARAMETERS
Number of iterations 5318
10 Heat Flux Thru Wall (Wm2) 9132
Heat Transfer Along Metal Skin Under Seal node to node qm[Wm2] Qm[W]
2 3 1619 1092 3 4 1612 1081 4 5 1660 1019 5 6 1645 1010 6 1 1626 1051 1 8 1601 1041 8 9 1569 1020 9 10 1521 9922
Maximum difference () 9101
Edge loss computed directly from steel skin 1T at centerline 1645
Heat fluxes in thru the section along the centerline [Wm2]
j flux 10 0 4284 4691 1 2246 2459 2 3513 3841 3 4554 4981 4 5311 5881 5 6001 6512 6 6488 1104 1 6868 1520
102
10
20
30
40
50
60
70
8 7169 7850 9 7412 8117
7612 8335 11 7778 8517 12 7918 8670 13 8037 8800 14 8139 8912 15 8227 9008 16 8303 9092 17 8369 9164 18 8428 9228 19 8479 9285
8525 9334 21 8565 9379 22 8601 9418 23 8634 9454 24 8663 9486 25 8690 9515 26 8714 9542 27 8736 9566 28 8756 9588 29 8775 9609
8793 9628 31 8809 9645 32 8824 9662 33 8838 9677 34 8851 9692 35 8863 9705 36 8875 9718 37 8886 9730 38 8896 9742 39 8906 9752
8916 9763 41 8925 9772 42 8933 9782 43 8941 9791 44 8949 9799 45 8956 9807 46 8963 9815 47 8970 9822 48 8976 9829 49 8982 9836
8988 9842 51 8994 9848 52 8999 9854 53 9004 9859 54 9009 9864 55 9013 9869 56 9017 9874 57 9021 9878 58 9025 9883 59 9029 9887
9032 9890 61 9036 9894 62 9039 9897 63 9042 9901 64 9044 9903 65 9047 9906 66 9049 9909 67 9051 9911 68 9053 9913 69 9055 9915
9057 9917 71 9058 9919
103
72 9059 9920 73 9061 9921 74 9062 9922 75 9062 9923 76 9063 9924 77 9063 9924 78 9064 9925 79 9064 9925
j local Qwall [Wl
-1 3215 0 -45410E-02 1 -50708E-02 2 -40940E-02 3 -33836E-02 4 -27620E-02 5 -23180E-02 6 -1 9628E-02 7 -1 6076E-02 8 -1 4300E-02 9 -12524E-02 10 -10748E-02 11 -98601E-03 12 -89722E-03 13 -80842E-03 14 -71962E-03 15 -63081E-03 16 -63082E-03 17 -54202E-03 18 -54202E-03 19 -45322E-03 20 -45322E-03 21 -45322E-03 22 -45321E-03 23 -36442E-03 24 -36442E-03 25 -36442E-03 26 -27562E-03 27 -27561E-03 28 -27561E-03 29 -27561E-03 30 -27561E-03 31 -18682E-03 32 -18682E-03 33 -27561E-03 34 -18682E-03 35 -18682E-03 36 -18681E-03 37 -18682E-03 38 -98018E-04 39 -98018E-04 40 -98018E-04 41 -98018E-04 42 -98018E-04 43 -98018E-04 44 -98018E-04 45 -98018E-04 46 -98018E-04 47 -18682E-03 48 -98018E-04 49 -98018E-04 50 -98018E-04 51 -98018E-04 52 -98018E-04
104
53 -98018E-04 54 -92160E-05 55 -98018E-04 56 -98018E-04 57 -98018E-04 58 -98018E-04 59 -98018E-04 60 -92160E-05 61 -98018E-04 62 -92160E-05 63 -98018E-04 64 -98018E-04 65 -92160E-05 66 -98018E-04 67 -98018E-04 68 -92245E-05 69 -92245E-05 70 -98018E-04 71 -98018E-04 72 -98018E-04 73 -92160E-05 74 -92160E-05 75 -92160E-05 76 -92160E-05 77 -92160E-05 78 -92160E-05 79 -92160E-05
Qwallff [Wm21 = 1442 Qwallff [WI = 2775
Fresh Food Nodal Temperatures
x(mm) v(mm) 1125 3375 5625 7875 10125 12375 14625 16875 19125 21375
125 1761 1755 1748 1741 1734 1727 172 1713 1706 17 375 1768 1753 1738 1723 1707 169 1671 165 1624 1589 625 1775 1752 173 1706 1682 1656 1626 1593 1552 15 875 1781 1751 1722 1691 1659 1625 1587 1544 1494 1434
1125 -1787 1751 1715 1678 1639 1598 1553 1504 1448 1384 1375 1792 1751 1709 1667 1622 1576 1526 1471 1412 1346 1625 1798 1752 1705 1658 1609 1557 1503 1446 1384 ll17 1875 1803 1753 1702 165 1597 1543 1485 1425 1362 1294 2125 1808 1754 17 1645 1589 1531 1471 1409 1344 1276 2375 1813 1756 1699 1641 1582 1522 146 1396 133 1262 2625 1817 1758 1698 1638 1577 1515 1451 1386 132 1251 2875 1822 176 1698 1636 1573 151 1445 1379 1311 1242 3125 1826 1762 1699 1635 1571 1506 144 1373 1304 1235 3375 183 1765 17 1635 1569 1503 1436 1368 1299 1229 3625 1834 1768 1701 1635 1568 1501 1433 1364 1295 1225 3875 1837 177 1703 1635 1568 15 1431 1362 1292 1222 4125 1841 1773 1705 1636 1568 1499 143 136 129 1219 4375 1845 1776 1707 1638 1568 1499 1429 1359 1289 1218 4625 1848 1778 1709 1639 1569 1499 1429 1358 1288 1216 4875 1851 1781 1711 164 157 15 1429 1358 1287 1216 5125 1854 1784 1713 1642 1571 15 1429 1358 1287 1215 5375 1857 1786 1715 1644 1573 1501 143 1358 1287 1215 5625 186 1789 1717 1646 1574 1502 1431 1359 1287 1215
105
5875 1863 1791 1719 1647 1576 1504 1432 136 1288 1215 6125 1866 1794 1721 1649 1577 1505 1433 136 1288 1216 6375 1868 1796 1723 1651 1579 1506 1434 1361 1289 1216 6625 1871 1798 1725 1653 158 1508 1435 1362 129 1217 6875 1873 18 1727 1655 1582 1509 1436 1363 1291 1218 7125 1876 1803 1729 1656 1583 151 1437 1364 1291 1218 7375 1878 1805 1731 1658 1585 1512 1439 1366 1292 1219 7625 188 1807 1733 166 1587 1513 144 1367 1293 122 7875 1882 1809 1735 1661 1588 1515 1441 1368 1294 1221 8125 1884 181 1737 1663 159 1516 1442 1369 1295 1222 8375 1886 1812 1738 1665 1591 1517 1444 137 1296 1223 8625 1888 1814 174 1666 1592 1519 1445 1371 1297 1224 8875 189 1816 1742 1668 1594 152 1446 1372 1298 1225 9125 1892 1817 1743 1669 1595 1521 1447 1373 1299 1225 9375 1893 1819 1745 1671 1596 1522 1448 1374 13 1226 9625 1895 182 1746 1672 1598 1524 1449 1375 1301 1227 9875 1896 1822 1748 1673 1599 1525 145 1376 1302 1228 10125 1898 1823 1749 1674 16 1526 1451 1377 1303 1229 10375 1899 1825 175 1676 1601 1527 1452 1378 1304 123 10625 1901 1826 1751 1677 1602 1528 1453 1379 1305 123 10875 1902 1827 1753 1678 1603 1529 1454 138 1305 1231 11125 1903 1828 1754 1679 1604 153 1455 1381 1306 1232 11375 1904 183 1755 168 1605 1531 1456 1381 1307 1232 11625 1906 1831 1756 1681 1606 1532 1457 1382 1308 1233 11875 1907 1832 1757 1682 1607 1532 1458 1383 1308 1234 12125 1908 1833 1758 1683 1608 1533 1458 1384 1309 1234 12375 1909 1834 1759 1684 1609 1534 1459 1384 131 1235 12625 191 1835 176 1685 161 1535 146 1385 131 1235 12875 1911 1836 1761 1686 1611 1536 1461 1386 1311 1236 13125 1912 1837 1761 1686 1611 1536 1461 1386 1311 1236 13375 1913 1837 1762 1687 1612 1537 1462 1387 1312 1237 13625 1913 1838 1763 1688 1613 1538 1462 1387 1312 1237 13875 1914 1839 1764 1688 1613 1538 1463 1388 1313 1238 14125 1915 184 1764 1689 1614 1539 1464 1388 1313 1238 14375 1916 184 1765 169 1614 1539 1464 1389 1314 1239 14625 1916 1841 1766 169 1615 154 1465 1389 1314 1239 14875 1917 1842 1766 1691 1616 154 1465 139 1315 1239 15125 1918 1842 1767 1691 1616 1541 1465 139 1315 124 15375 1918 1843 1767 1692 1616 1541 1466 1391 1315 124 15625 1919 1843 1768 1692 1617 1542 1466 1391 1316 124 15875 1919 1844 1768 1693 1617 1542 1467 1391 1316 1241 16125 192 1844 1769 1693 1618 1542 1467 1392 1316 1241 16375 192 1844 1769 1694 1618 1543 1467 1392 1317 1241 16625 192 1845 1769 1694 1618 1543 1468 1392 1317 1241 16875 1921 1845 177 1694 1619 1543 1468 1392 1317 1242 17125 1921 1846 177 1694 1619 1544 1468 1393 1317 1242 17375 1921 1846 177 1695 1619 1544 1468 1393 1317 1242 17625 1922 1846 1771 1695 1619 1544 1469 1393 1318 1242 17875 1922 1846 1771 1695 162 1544 1469 1393 1318 1242 18125 1922 1847 1771 1695 162 1544 1469 1393 1318 1243 18375 1922 1847 1771 1696 162 1545 1469 1394 1318 1243 18625 1923 1847 1771 1696 162 1545 1469 1394 1318 1243 18875 1923 1847 1771 1696 162 1545 1469 1394 1318 1243 19125 1923 1847 1772 1696 162 1545 1469 1394 1318 1243 19375 1923 1847 1772 1696 162 1545 1469 1394 1318 1243 19625 1923 1847 1772 1696 1621 1545 1469 1394 1318 1243 19875 1923 1847 1772 1696 1621 1545 1469 1394 1318 1243
106
x(mm) y(mm) 23625 25875 28125 30375 32625 34875 37125 39375 41625 43875
125 1694 1662 1287 1033 8577 7336 6444 5795 5324 4995 375 1536 144 125 1068 9163 7946 6974 6189 5532 4944 625 1431 1334 1203 1066 9379 8252 7275 6423 5657 4935 875 136 127 1164 1051 9408 8374 7423 6548 573 4941
1125 131 1226 1132 1034 9353 8394 7477 6605 5766 4948 1375 1273 1193 1107 1017 9262 836 7478 6618 5779 4952 1625 1245 1168 1086 1002 9162 8302 7449 6607 5776 4951 1875 1223 1148 1069 9886 9064 8236 7408 6583 5764 4948 2125 1205 1132 1055 977 8974 8169 7362 6554 5747 4941 2375 1191 1119 1044 9671 8893 8107 7316 6522 5728 4933 2625 118 1108 1034 9588 8824 8051 7273 6492 5709 4925 2875 1172 11 1026 9518 8764 8002 7235 6464 5691 4916 3125 1164 1093 102 946 8713 796 7201 6439 5674 4908 3375 1159 1087 1015 9412 8671 7924 7172 6417 566 49 3625 1154 1083 101 9373 8636 7894 7148 6399 5647 4894 3875 1151 1079 1007 9341 8608 7869 7128 6383 5636 4888 4125 1148 1077 1004 9316 8585 7849 7111 637 5627 4883 4375 1146 1074 1002 9296 8566 7833 7097 6359 5619 4879 4625 1145 1073 1001 9281 8552 7821 7087 6351 5613 4875 4875 1144 1072 9995 927 8541 7811 7078 6344 5609 4872 5125 1143 1071 9987 9261 8533 7803 7072 6339 5605 487 5375 1143 1071 9982 9256 8528 7798 7067 6335 5602 4868 5625 1143 107 9979 9253 8524 7795 7064 6332 56 4867 5875 1143 107 9978 9251 8522 7793 7062 6331 5599 4866 6125 1143 1071 9979 9251 8522 7792 7061 633 5598 4866 6375 1144 1071 9981 9252 8523 7792 7061 633 5598 4865 6625 1144 1071 9984 9255 8524 7793 7062 633 5598 4865 6875 1145 1072 9988 9258 8526 7795 7063 6331 5598 4865 7125 1145 1072 9993 9261 8529 7797 7065 6332 5599 4866 7375 1146 1073 9998 9265 8533 78 7067 6333 56 4866 7625 1147 1074 10 927 8536 7803 7069 6335 5601 4867 7875 1148 1074 1001 9275 854 7806 7072 6337 5602 4867 8125 1148 1075 1001 928 8545 7809 7074 6339 5603 4868 8375 1149 1076 1002 9285 8549 7813 7077 6341 5605 4869 8625 115 1076 1003 929 8553 7817 708 6343 5606 4869 8875 1151 1077 1003 9295 8558 782 7083 6345 5608 487 9125 1152 1078 1004 93 8562 7824 7086 6347 5609 4871 9375 1152 1078 1004 9306 8567 7828 7089 635 5611 4872 9625 1153 1079 1005 9311 8571 7831 7092 6352 5612 4873 9875 1154 108 1006 9316 8575 7835 7094 6354 5614 4873 10125 1155 108 1006 9321 858 7838 7097 6356 5615 4874 10375 1155 1081 1007 9326 8584 7842 71 6358 5617 4875 10625 1156 1082 1007 933 8588 7845 7103 636 5618 4876 10875 1157 1082 1008 9335 8592 7848 7105 6362 5619 4876 11125 1157 1083 1008 9339 8596 7852 7108 6364 5621 4877 11375 1158 1083 1009 9344 8599 7855 711 6366 5622 4878 11625 1158 1084 1009 9348 8603 7858 7113 6368 5623 4879 11875 1159 1084 101 9352 8606 7861 7115 637 5625 4middot879 12125 116 1085 101 9356 861 7864 7117 6372 5626 488 12375 116 1085 1011 936 8613 7866 712 6373 5627 488 12625 1161 1086 1011 9363 8616 7869 7122 6375 5628 4881 12875 1161 1086 1011 9367 8619 7871 7124 6376 5629 4882 13125 1162 1087 1012 937 8622 7874 7126 6378 563 4882 13375 1162 1087 1012 9373 8625 7876 7128 6379 5631 4883 13625 1162 1087 1013 9376 8627 7878 7129 6381 5632 4883
107
13875 1163 1088 1013 9379 863 788 7131 6382 5633 4884 14125 1163 1088 1013 9382 8632 7882 7133 6383 5634 4884 14375 1164 1089 1013 9384 8634 7884 7134 6384 5634 4885 14625 1164 1089 1014 9387 8636 7886 7136 6385 5635 4885 14875 1164 1089 1014 9389 8638 7888 7137 6386 5636 4885 15125 1165 1089 1014 9392 864 7889 7138 6387 5637 4886 15375 1165 109 1015 9394 8642 7891 714 6388 5637 4886 15625 1165 109 1015 9396 8644 7892 7141 6389 5638 4886 15875 1165 109 1015 9398 8646 7894 7142 639 5638 4887 16125 1166 109 1015 9399 8647 7895 7143 6391 5639 4887 16375 1166 1091 1015 9401 8649 7896 7144 6392 5639 4887 16625 1166 1091 1016 9403 865 7897 7145 6392 564 4888 16875 1166 1091 1016 9404 8651 7898 7146 6393 564 4888 17125 1167 1091 1016 9405 8652 7899 7146 6394 5641 4888 17375 1167 1091 1016 9406 8653 79 7147 6394 5641 4888 17625 1167 1091 1016 9407 8654 7901 7148 6395 5641 4888 17875 1167 1092 1016 9408 8655 7902 7148 6395 5642 4889 18125 1167 1092 1016 9409 8656 7902 7149 6395 5642 4889 18375 1167 1092 1016 941 8656 7903 7149 6396 5642 4889 18625 1167 1092 1016 9411 8657 7903 715 6396 5642 4889 18875 1167 1092 1017 9411 8657 7904 715 6396 5643 4889 19125 1167 1092 1017 9412 8658 7904 715 6396 5643 4889 19375 1167 1092 1017 9412 8658 7904 715 6397 5643 4889 19625 1167 1092 1017 9412 8658 7904 715 6397 5643 4889 19875 1168 1092 1017 9412 8658 7904 715 6397 5643 4889
F4 Freezer Wall Simulation Output
INPUT PARAMETERS
Section Dimensions (mm) Width 5600 Length 2000 Depth 1000 Steel skin thickness 6500 Plastic skin thickness 2500
Mesh Geometry dx 2800 dy 2500 Number nodes in x-direction 20 Number nodes in y-direction 80 Number of steel skin nodes (including corner 00) 9 Steel nodes under the seal 2 to 8
Steel skin conductivity (Wm K) 5400 Foam insulation conductivity (Wm K) 27000E-02 Plastic skin conductivity (Wm K) 1500 Outside h (Wm2 K) 6870 Inside h (Wm2 K) 6410 Outside Temp (C) 2100 Inside Temp (C) -1000
OUPUT PARAMETERS
108
Number of iterations 5409
Heat Transfer for the Section OVerall Heat Transfer (WI 4518 10 Heat Flux Thru Wall (Wm21 1362
Heat Transfer Along Metal Skin Under Seal node to node
2 3 3 4 4 5 5 6 6 7 7 8
Maximum difference
qm[Wm2) Om(W) 3026 1967 3008 1955 2981 1938 2944 1914 2892 1880 2820 1833
(1 6799
Edge loss computed from qe=q20-q1D 1760
Edge loss compusteel skin AT
ted directly from at centerline 2981
Heat fluxes in thru the section along the centerline [Wm2)
j flux UO 0 7762 5698 1 3711 2724 2 5678 41 68 3 7275 5341 4 8508 6246 5 9437 6927 6 1013 7438 7 1066 7823 8 1106 8117 9 1137 8347 10 1162 8529 11 1182 8678 12 1199 8801 13 1213 8904 14 1225 8992 15 1235 9068 16 1244 9135 17 1252 9193 18 1259 9245 19 1266 9291 20 1271 9333 21 1276 9370 22 1281 9405 23 1285 9436 24 1289 9464 25 1293 9491 26 1296 9515 27 1299 9538 28 1302 9559 29 1305 9578 30 1307 9596 31 1310 9614 32 1312 9630 33 1314 9645 34 1316 9659 35 1318 9673 36 1319 9685 37 1321 9697
109
38 1323 9709 39 1324 9720 40 1325 9730 41 1327 9740 42 1328 9749 43 1329 9758 44 1330 9767 45 1332 9775 46 1333 9783 47 1334 97bull 90 48 1335 9797 49 1336 9804 50 1336 9810 51 1337 9816 52 1338 9822 53 1339 9828 54 1340 9833 55 1340 9838 56 1341 9843 57 1341 9847 58 1342 9852 59 1343 9856 60 1343 9859 61 1344 9863 62 1344 9866 63 1344 9870 64 1345 9873 65 1345 9875 66 1346 9878 67 1346 9880 68 1346 9882 69 1347 9884 70 1347 9886 71 1347 9888
72 1347 9889 73 1347 9891 74 1347 9892 75 1348 9893 76 1348 9893 77 1348 9894 78 1348 9894 79 1348 9894
j local Qwall [WI
-1 3067 0 -36774E-02 1 -40214E-02 2 -32314E-02 3 -25994E-02 4 -20859E-02 5 -16909E-02 6 -14144E-02 7 -12169E-02 8 -10589E-02 9 -90092E-03 10 -78242E-03 11 -70342E-03 12 -66392E-03 13 -58492E-03 14 -54542E-03 15 -50592E-03 16 -46642E-03 17 -42692E-03 18 -42692E-03
110
19 -38742E-03 20 -34792E-03 21 -30842E-03 22 -30842E-03 23 -30842E-03 24 -26892E-03 25 -26892E-03 26 -22942E-03 27 -22942E-03 28 -22942E-03 29 -22942E-03 30 -18992E-03 31 -1 8992E-03 32 -18992E-03 33 -18992E-03 34 -1 8992E-03 35 -1 5042E-03 36 -1 8992E-03 37 -15042E-03 38 -1 5042E-03 39 -11092E-03 40 -11092E-03 41 -11092E-03 42 -11092E-03 43 -11092E-03 44 -11092E-03 45 -11092E-03 46 -11092E-03 47 -71417E-04 48 -11092E-03 49 -71421E-04 50 -11092E-03 51 -71417E-04 52 -11092E-03 53 -71417E-04 54 -71421E-04 55 -71421E-04 56 -71417E-04 57 -31916E-04 58 -31920E-04 59 -31916E-04 60 -31916E-04 61 -71417E-04 62 -11421E-04 63 -71421E-04 64 -31920E-04 65 -31920E-04 66 -71417E-04 67 -31916E-04 68 -71417E-04 69 -31920E-04 70 -71421E-04 71 -31920E-04 72 -31920E-04 73 -71417E-04 74 -31916E-04 75 -31916E-04 76 -31916E-04 77 -31916E-04 78 -71417E-04 79 -71417E-04
Qwallfz [Wm2J = 2895 Qwallfz [WJ = 2721
111
Freezer Wan Nodal Temperatures
x(mm) y1mm 14 42 70 98 126 154 182 210 238 266
125 1507 1492 1477 1461 1445 143 1415 14 1385 1338 375 1519 1489 1458 1426 1392 1353 1307 1247 1154 972 625 1531 1486 1441 1393 1341 1282 1212 1121 9925 7989 875 1542 1484 1425 1363 1296 1221 1132 1023 8837 7014
1125 1553 1483 1412 1338 1258 117 1069 9508 809 6396 1375 1563 1483 1401 1317 1227 1129 102 8969 7563 5974 1625 1572 1483 1393 13 1202 1097 9824 8568 7184 5673 1875 1582 1485 1387 1287 1182 1072 9537 8269 6906 5452 2125 1591 1488 1384 1277 1167 1053 9321 8046 67 5288 2375 1599 1491 1382 1271 1157 1039 916 7881 6547 5164 2625 1608 1495 1381 1266 1149 1028 9041 7758 6433 5071 2875 1616 1499 1382 1264 1144 1021 8955 7668 6349 5002 3125 1623 1504 1384 1263 114 1016 8895 7604 6288 495 3375 1631 1509 1386 1263 1139 1013 8854 7559 6245 4913 3625 1638 1514 1389 1264 1138 1011 8829 753 6216 4888 3875 1645 1519 1393 1266 1139 1011 8816 7513 6198 4872 4125 1652 1524 1396 1269 114 1011 8813 7505 6188 4863 4375 1658 1529 14 1271 1142 1012 8817 7505 6185 486 4625 1664 1534 1405 1275 1144 1014 8826 751 6188 4861 4875 167 1539 1409 1278 1147 1016 884 752 6195 4867 5125 1676 1544 1413 1281 115 1018 8858 7533 6206 4875 5375 1682 1549 1417 1285 1153 102 8877 755 6219 4886 5625 1687 1554 1421 1289 1156 1023 8899 7568 6235 4899 5875 1692 1559 1425 1292 1159 1026 8923 7588 6252 4914 6125 1698 1563 143 1296 1162 1028 8947 7609 627 493 6375 1702 1568 1434 1299 1165 1031 8972 763 6289 4946 6625 1707 1572 1438 1303 1169 1034 8997 7653 6308 4964 6875 1712 1576 1441 1306 1172 1037 9022 7675 6329 4982 7125 1716 158 1445 131 1175 104 9048 7698 6349 5 7375 172 1584 1449 1313 1178 1043 9073 7721 6369 5018 7625 1724 1588 1452 1317 1181 1045 9098 7744 639 5036 7875 1728 1592 1456 132 1184 1048 9123 7766 641 5054 8125 1732 1595 1459 1323 1187 1051 9147 7788 643 5072 8375 1736 1599 1462 1326 1189 1053 917 781 645 509 8625 1739 1602 1465 1329 1192 1056 9194 7831 6469 5108 8875 1743 1605 1468 1332 1195 1058 9216 7852 6488 5125 9125 1746 1609 1471 1334 1197 1061 9238 7872 6507 5142 9375 1749 1612 1474 1337 12 1063 926 7892 6525 5158 9625 1752 1615 1477 134 1202 1065 9281 7911 6542 5174 9875 1755 1617 148 1342 1205 1067 9301 793 656 519 10125 1758 162 1482 1344 1207 1069 9321 7948 6576 5205 10375 1761 1623 1485 1347 1209 1071 934 7966 6593 522 10625 1763 1625 1487 1349 1211 1073 9358 7983 6608 5234 10875 1766 1627 1489 1351 1213 1075 9376 7999 6623 5248 11125 1768 163 1491 1353 1215 1077 9393 8015 6638 5262 11375 1771 1632 1494 1355 1217 1079 941 8031 6652 5275 11625 1773 1634 1496 1357 1219 1081 9426 8045 6666 5287 11875 1775 1636 1498 1359 1221 1082 9441 806 6679 53 12125 1777 1638 1499 1361 1222 1084 9456 8073 6692 5311 12375 1779 164 1501 1362 1224 1085 947 8087 6704 5322 12625 1781 1642 1503 1364 1225 1087 9483 8099 6716 5333 12875 1783 1644 1505 1366 1227 1088 9496 8111 6727 5344
112
13125 1784 1645 1506 1367 1228 109 9509 8123 6738 5353 13375 1786 1647 1508 1369 123 1091 9521 8134 6748 5363 13625 1788 1648 1509 137 1231 1092 9532 8145 6758 5372 13875 1789 165 151 1371 1232 1093 9543 8155 6768 5381 14125 1791 1651 1512 1373 1233 1094 9554 8165 6777 5389 14375 1792 1652 1513 1374 1235 1095 9564 8174 6785 5397 14625 1793 1654 1514 1375 1236 1096 9573 8183 6793 5404 14875 1794 1655 1515 1376 1237 1097 9582 8191 6801 5412 15125 1796 1656 1516 1377 1238 1098 959 8199 6808 5418 15375 1797 1657 1517 1378 1238 1099 9598 8206 6815 5425 15625 1798 1658 1518 1379 1239 11 9606 8213 6822 5431 15875 1799 1659 1519 138 124 1101 9613 822 6828 5436 16125 18 166 152 138 1241 1101 9619 8226 6834 5442 16375 18 1661 1521 1381 1242 1102 9626 8232 6839 5446 16625 1801 1661 1521 1382 1242 1103 9631 8237 6844 5451 16875 1802 1662 1522 1382 1243 1103 9637 8242 6848 5455 17125 1803 1663 1523 1383 1243 1104 9642 8247 6853 5459 17375 1803 1663 1523 1384 1244 1104 9646 8251 6857 5463 17625 1804 1664 1524 1384 1244 1105 965 8255 686 5466 17875 1804 1664 1524 1384 1245 1105 9654 8258 6863 5469 18125 1805 1665 1525 1385 1245 1105 9657 8261 6866 5471 18375 1805 1665 1525 1385 1245 1106 966 8264 6869 5474 18625 1805 1665 1525 1385 1246 1106 9662 8266 6871 5476 18875 1806 1666 1526 1386 1246 1106 9664 8268 6872 5477 19125 1806 1666 1526 1386 1246 1106 9666 827 6874 5479 19375 1806 1666 1526 1386 1246 1106 9667 8271 6875 548 19625 1806 1666 1526 1386 1246 1107 9668 8271 6876 548 19875 1806 1666 1526 1386 1246 1107 9668 8272 6876 5481
x(mm) v(mm) 294 322 350 378 406 434 462 490 518 546
125 549 054 -27 -5 -624 -727 -8 -85 -89 -92 375 548 171 -12 -338 -5 -624 -719 -795 -858 -914 625 51 22 -032 -24 -408 -543 -654 -748 -83 -907 875 474 238 0182 -175 -34 -482 -603 -71 -807 -898
1125 445 243 048 -132 -293 -436 -564 -68 -787 -89 1375 423 243 0653 -103 -259 -402 -534 -656 -772 -883 1625 406 24 0752 -084 -236 -378 -511 -638 -759 -877 1875 393 237 0808 -071 -219 -36 -495 -624 -749 -871 2125 382 233 0837 -063 -208 -348 -483 -614 -741 -867 2375 374 23 085 -058 -2 -339 -474 -606 -735 -863 2625 368 227 0855 -055 -195 -332 -467 -6 -731 -86 2875 363 225 0855 -053 -191 -328 -462 -596 -728 -858 3125 36 223 0853 -052 -189 -324 -459 -593 -725 -856 3375 357 221 0851 -051 -187 -322 -457 -59 -723 -855 3625 355 22 0849 -05 -186 -32 -455 -588 -722 -854 3875 354 219 0849 -049 -185 -319 -453 -587 -72 -853 4125 353 219 0849 -049 -184 -318 -452 -586 -72 -853 4375 353 219 0852 -049 -183 -317 -451 -585 -719 -852 4625 353 219 0855 -048 -183 -317 -451 -584 -718 middot852 4875 353 22 0861 -047 -182 -316 -45 -584 -718 -852 5125 354 22 0867 -047 -181 -315 -449 -584 -717 -851 5375 355 221 0875 -046 -181 -315 -449 -583 -717 -851 5625 356 222 0884 -045 -18 -314 -448 -582 -717 -851 5875 358 223 0894 -044 -179 -313 -448 -582 -716 -851 6125 359 225 0904 -043 -178 -313 -447 -582 -716 -851 6375 36 226 0915 -043 -177 -312 -447 -581 -716 -85
113
6625 362 227 0927 -042 -177 -311 -446 -581 -716 -85 6875 363 229 0939 -04 -176 -311 -445 -58 -715 -85 7125 365 23 0951 -039 -175 -31 -445 -58 -715 -85 7375 367 232 0964 -038 -174 -309 -444 -579 -715 -85 7625 368 233 0976 -037 -173 -308 -444 -579 -714 -85 7875 37 234 0989 -036 -172 -308 -443 -578 -714 -849 8125 371 236 1 -035 -171 -307 -442 -578 -714 -849 8375 373 237 101 -034 -17 -306 -442 -578 -713 -849 8625 375 239 103 -033 -169 -305 -441 -577 -713 -849 8875 376 24 104 -032 -168 -305 -441 -577 -713 -849 9125 378 241 105 -031 -168 -304 -44 -576 -712 -849 9375 379 243 106 -03 -167 -303 -439 -576 -712 -848 9625 381 244 107 -029 -166 -302 -439 -575 -712 -848 9875 382 245 109 -028 -165 -302 -438 -575 -712 -848 10125 384 246 11 -027 -164 -301 -438 -574 -711 -848 10375 385 248 111 -026 -163 -3 -437 -574 -711 -848 10625 386 249 112 -025 -163 -3 -437 -574 -711 -848 10875 387 25 113 -024 -162 -299 -436 -573 -711shy -848 11125 389 251 114 -023 -161 -298 -436 -573 -71 -848 11375 39 252 115 -022 -16 -298 -435 -573 -71 -847 11625 391 253 115 -022 -16 -297 -435 -572 -71 -847 11875 392 254 116 -021 -159 -297 -434 -572 -709 -847 12125 393 255 117 -02 -158 -296 -434 -572 -709 -847 12375 394 256 118 -019 -158 -296 -434 -571 -709 -847 12625 395 257 119 -019 -157 -295 -433 -571 -709 -847 12875 396 258 12 -018 -157 -295 -433 -571 -709 -847 13125 397 259 12 -017 -156 -294 -432 -57 -709 -847 13375 398 259 121 -017 -155 -294 -432 -57 -708 -847 13625 399 26 122 -016 -155 -293 -432 -57 -708 -846 13875 399 261 122 -016 -154 -293 -431 -57 -708 -846 14125 4 262 123 -015 -154 -292 -431 -569 -708 -846 14375 401 262 124 -015 -154 -292 -431 -569 -708 -846 14625 402 263 124 -014 -153 -292 -43 -569 -707 -846 14875 402 263 125 -014 -153 -291 -43 -569 -707 -846 15125 403 264 125 -013 -152 -291 -43 -569 -707 -846 15375 403 264 126 -013 -152 -291 -43 -568 -707 -846 15625 404 265 126 -012 -152 -291 -429 -568 -707 -846 15875 405 265 126 -012 -151 -29 -429 -568 -707 -846 16125 405 266 127 -012 -151 -29 -429 -568 -707 -846 16375 405 266 127 -011 -151 -29 -429 -568 -707 -846 16625 406 267 128 -011 -151 -29 -429 -568 -707 -846 16875 406 267 128 -011 -15 -289 -428 -568 -707 -845 17125 407 267 128 -01 -15 -289 -428 -567 -706 -845 17375 407 268 128 -01 -15 -289 -428 -567 -706 -845 17625 407 268 129 -01 -15 -289 -428 -567 -706 -845 17875 407 268 129 -01 -15 -289 -428 -567 -706 -845 18125 408 268 129 -01 -15 -289 -428 -567 -706 -845 18375 408 269 129 -01 -149 -289 -428 -567 -706 -845 18625 408 269 129 -001 -149 -288 -428 -567 -706 -845 18875 408 269 129 -001 -149 -288 -428 -567 -706 -845 19125 408 269 13 -001 -149 -288 -428 -567 -706 -845 19375 409 269 13 -001 -149 -288 -428 -567 -706 -845 19625 409 269 13 -001 -149 -288 -428 -567 -706 -845 19875 409 269 13 -001 -15 -288 -428 -567 -706 -845
114
FS Fresh Food Wan Simulation Output Including Anti-sweat Condenser Tube
INPUT PARAMETERS
Section Dimensions (mm) Hidth 4500 Length 2000 Depth 2960 Steel skin thickness 6500 Plastic skin thickness 2500
Mesh Geometry dx 2250 dy 2500 Number nodes in x-direction 20 Number nodes in y-direction 80 Number of steel skin nodes (including corner 00) 11 Steel nodes under the seal 2 to 10 Tube located at node 6
Steel skin conductivity (Him K) 5400 Foam insulation conductivity (Him K) 27000E-02 Plastic skin conductivity (Him K) 1500 Outside h (Hm2 K) 6870 Inside h (Hm2 K) 6700 Outside Temp (C) 2100 Inside Temp (C) 4000
OUPUT PARAMETERS
Number of iterations 602
10 Heat Flux Thru Hall (Hm2) 9132
Heat Transfer Along Metal Skin Under Seal node to node qm[Hm21 Qm[HI
2 3 -15052E+04 -2896 3 4 -15125E+04 -2910 4 5 -15198E+04 -2924 5 6 -15274E+04 -2939 6 7 3996 7688 7 8 3898 7500 8 9 3790 7292 9 10 3662 7045
Maximum difference () 1243
j qleft [HI qright [HI -1 -2957 7832 0 -92065E-02 -38838E-02 1 -77348E-02 -48044E-02 2 -51596E-02 -30284E-02 3 -32948E-02 -15188E-02 4 -1 9628E-02 -54201E-03 5 -98600E-03 16837E-03 6 -36442E-03 70ll8E-03 7 79586E-04 96757E-03 8 43478E-03 11452E-02 9 70118E-03 12340E-02 10 87877E-03 12340E-02
115
11 87879E-03 13228E-02 12 10564E-02 12340E-02 13 10564E-02 11452E-02 14 96759E-03 11452E-02 15 87877E-03 10564E-02 16 87879E-03 87877E-03 17 78999E-03 87877E-03 18 61238E-03 78999E-03 19 61240E-03 61237E-03 20 52359E-03 52358E-03 21 34598E-03 34598E-03 22 25719E-03 25717E-03 23 16838E-03 16839E-03 24 79586E-04 25 -98018E-04 26 -18681E-03 27 -27561E-03 28 -36442E-03 29 -54202E-03 30 -54202E-03 31 -7 1962E-03 32 -80842E-03 33 -8 9721E-03 34 -98602E-03 35 -10748E-02 36 -11636E-02 37 -12524E-02 38 -1 3412E-02 39 -1 4300E-02 40 -15188E-02 41 -1 5188E-02 42 -1 6076E-02 43 -16964E-02 44 -17852E-02 45 -1 7852E-02 46 -1 8740E-02 47 -19628E-02 48 -19628E-02 49 -19628E-02 50 -20516E-02 51 -21404E-02 52 -22292E-02 53 -22292E-02 54 -23180E-02 55 -23180E-02 56 -23180E-02 57 -24068E-02
79578E-04 -98018E-04 -1 8682E-03 -27561E-03 -45322E-03 -54202E-03 -71962E-03 -71962E-03 -8 9722E-03 -8 9722E-03 -10748E-02 -11636E-02 -12524E-02 -13412E-02 -14300E-02 -1 5188E-02 -16076E-02 -16964E-02 -16964E-02 -17852E-02 -18740E-02 -19628E-02 -20516E-02 -20516E-02 -21404E-02 -22292E-02 -22470E-02 -22381E-02 -22647E-02 -23358E-02 -23447E-02 -23802E-02 -24512E-02 -24690E-02
58 -23979E-02 -25223E-02 59 -24423E-02 60 -24246E-02 61 -24423E-02 62 -24779E-02 63 -25400E-02 64 -25400E-02 65 -25667E-02 66 -26199E-02 67 -26022E-02 68 -26111E-02 69 -26377E-02 70 -26022E-02 71 -26732E-02 72 -26821E-02 73 -26199E-02 74 -26643E-02
-25489E-02 -25755E-02 -25933E-02 -2 6199E-02 -26466E-02 -26643E-02 -26821E-02 -26910E-02 -27087E-02 -27265E-02 -27354E-02 -27443E-02 -27531E-02 -27620E-02 -27620E-02 -27709E-02
116
75 -26377E-02 -27709E-02 76 -26377E-02 -27709E-02 77 -26555E-02 -27709E-02 78 -26910E-02 -27620E-02 79 -26555E-02 -27620E-02
Qleft [ii] -3079 Qright [ii] 6756 Percent entering cabinet 1800
Fresh Food Nodal Temperatures (Condenser Tube)
x(mm) y(mm) 1125 3375 5625 7875 10125 12375 14625 16875 19125 21375
19875 126 1206 1154 1104 1055 1007 9608 9158 872 8294 19625 1259 1205 1153 1103 1054 1006 9602 9152 8715 8289 19375 1259 1205 1153 1102 1053 1006 9598 9149 8711 8285 19125 1259 1205 1153 1102 1053 1006 9596 9147 871 8284 18875 1259 1205 1153 1102 1053 1006 9596 9147 871 8284 18625 1259 1205 1153 1103 1054 1006 9599 915 8712 8286 18375 126 1206 1154 1103 1054 1007 9604 9154 8716 829 18125 1261 1207 1155 1104 1055 1007 9611 9161 8722 8295 17875 1263 1209 1156 1105 1056 1008 962 9169 873 8302 17625 1264 121 1158 1107 1058 101 9632 918 874 8311 17375 1266 1212 116 1109 1059 1011 9646 9193 8752 8322 17125 1269 1215 1162 1111 1061 1013 9663 9209 8766 8335 16875 1272 1217 1164 1113 1063 1015 9682 9226 8783 835 16625 1275 122 1167 1116 1066 1017 9704 9246 8801 8367 16375 1279 1224 117 1119 1069 102 9728 9269 8822 8386 16125 1282 1227 1174 1122 1072 1023 9755 9294 8845 8407 15875 1287 1231 1178 1126 1075 1026 9785 9322 887 843 15625 1292 1236 1182 113 1079 103 9818 9352 8898 8456 15375 1297 1241 1187 1134 1083 1034 9854 9385 8929 8484 15125 1302 1246 1192 1139 1088 1038 9892 9421 8962 8514 14875 1308 1252 1197 1144 1092 1042 9934 946 8998 8547 14625 1315 1258 1203 1149 1097 1047 9979 9502 9037 8583 14375 1322 1265 1209 1155 1103 1052 1003 9547 9078 8621 14125 1329 1272 1216 1162 1109 1058 1008 9595 9123 8662 13875 1337 1279 1223 1168 1115 1064 1014 9647 9171 8706 13625 1346 1287 1231 1176 1122 107 102 9703 9222 8753 13375 1355 1296 1239 1183 1129 1077 1026 9762 9277 8803 13125 1364 1305 1247 1191 1137 1084 1033 9824 9335 8856 12875 1374 1314 1256 12 1145 1092 104 9891 9396 8913 12625 1385 1325 1266 1209 1154 11 1047 9962 9462 8973 12375 1396 1335 1276 1219 1163 1109 1055 1004 9531 9037 12125 1408 1347 1287 1229 1173 1118 1064 1012 9605 9105 11875 1421 1359 1299 124 1183 1127 1073 102 9683 9176 11625 1434 1371 1311 1251 1194 1137 1082 1029 9765 9252 11375 1448 1385 1323 1263 1205 1148 1092 1038 9851 9332 11125 1462 1399 1336 1276 1217 1159 1103 1048 9943 9416 10875 1478 1413 135 1289 1229 1171 1114 1058 1004 9505 10625 1494 1429 1365 1303 1243 1184 1126 1069 1014 9598 10375 1511 1445 138 1318 1257 1197 1138 1081 1025 9696 10125 1528 1462 1397 1333 1271 121 1151 1093 1036 98 9875 1547 1479 1413 1349 1286 1225 1165 1106 1048 9908 9625 1566 1498 1431 1366 1302 124 1179 1119 106 1002
117
9375 1586 1517 145 1384 1319 1256 1194 1133 1073 1014 9125 1607 1537 1469 1402 1336 1272 1209 1147 1087 1027 8875 1629 1558 1489 1421 1355 129 1226 1163 1101 104 8625 1652 158 151 1441 1374 1308 1243 1179 1116 1054 8375 1676 1603 1532 1462 1394 1327 1261 1195 1131 1068 8125 17 1627 1555 1484 1415 1346 1279 1213 1148 1084 7875 1726 1652 1579 1507 1436 1367 1299 1231 1165 11 7625 1753 1678 1604 1531 1459 1389 1319 1251 1183 1116 7375 1781 1704 1629 1556 1483 1411 1341 1271 1202 1134 7125 1809 1732 1656 1581 1508 1435 1363 1292 1222 1152 6875 1839 1761 1684 1608 1533 146 1387 1314 1243 1172 6625 187 1791 1713 1636 156 1485 1411 1337 1264 1192 6375 1903 1823 1744 1666 1589 1512 1437 1362 1287 1214 6125 1936 1855 1775 1696 1618 1541 1464 1387 1312 1236 5875 197 1889 1808 1728 1649 157 1492 1414 1337 126 5625 2006 1923 1842 1761 1681 1601 1522 1443 1364 1285 5375 2043 196 1877 1795 1714 1633 1553 1473 1392 1312 5125 2081 1997 1914 1832 1749 1668 1586 1504 1422 134 4875 212 2036 1952 1869 1786 1704 1621 1538 1454 137 4625 2161 2076 1992 1909 1825 1741 1658 1573 1488 1403 4375 2203 2118 2034 195 1866 1782 1697 1611 1525 1437 4125 2246 2161 2077 1993 1909 1824 1738 1652 1564 1474 3875 229 2206 2123 2039 1955 1869 1783 1695 1606 1515 3625 2336 2253 217 2087 2003 1918 1831 1742 1651 1558 3375 2383 2302 222 2138 2055 197 1882 1793 1701 1606 3125 2432 2353 2273 2192 211 2026 1938 1848 1755 1658 2875 2482 2405 2328 225 217 2086 20 1909 1815 1715 2625 2533 2461 2387 2312 2234 2153 2067 1977 1881 178 2375 2586 2518 2449 2378 2304 2226 2142 2052 1955 1851 2125 264 2579 2516 2451 2381 2306 2225 2136 2039 1933 1875 2696 2642 2587 2529 2466 2396 2319 2232 2134 2026 1625 2753 2709 2664 2614 256 2497 2425 2341 2244 2133 1375 2811 278 2746 2708 2664 2611 2546 2468 2373 226 1125 2871 2854 2835 2811 278 2739 2685 2615 2524 2411 875 2932 2932 293 2923 2909 2885 2846 2787 2706 2595 625 2995 3014 3031 3045 3052 3049 3031 2989 2922 2824 375 3058 3098 3138 3175 3208 3234 3245 3223 3179 3109 125 3124 3185 3247 331 3373 3436 35 3483 3467 3451
x(mm) y(mm) 23625 25875 28125 30375 32625 34875 37125 39375 41625 43875
19875 7877 747 7071 6679 6294 5915 554 5168 4799 4432 19625 7872 7466 7067 6676 6291 5912 5538 5166 4798 4431 19375 7869 7463 7065 6674 6289 591 5536 5165 4797 443 19125 7868 7462 7063 6673 6288 591 5535 5165 4797 443 18875 7868 7462 7063 6673 6288 591 5535 5165 4796 443 18625 787 7463 7065 6674 6289 591 5536 5165 4797 443 18375 7873 7466 7067 6676 6291 5912 5537 5166 4797 443 18125 7878 747 7071 6679 6294 5914 5539 5167 4798 4431 17875 7884 7476 7076 6684 6298 5917 5542 5169 4799 4431 17625 7893 7483 7083 6689 6303 5921 5545 5172 4801 4432 17375 7903 7492 7091 6696 6309 5926 5549 5175 4803 4433 17125 7914 7503 71 6704 6316 5932 5553 5178 4806 4435 16875 7928 7515 7111 6714 6324 5939 5559 5182 4809 4436 16625 7943 7529 7123 6725 6333 5947 5565 5187 4812 4438 16375 796 7544 7137 6737 6343 5955 5572 5192 4815 444 16125 7979 7561 7152 675 6355 5965 558 5198 4819 4442
118
15875 8001 7581 7169 6765 6368 5976 5589 5205 4824 4445 15625 8024 7601 7188 6781 6382 5987 5598 5212 4829 4447 15375 8049 7624 7208 6799 6397 6 5608 522 4834 445 15125 8077 7649 723 6819 6414 6014 562 5229 484 4453 14875 8107 7676 7254 684 6432 603 5632 5238 4847 4457 14625 8139 7705 728 6862 6451 6046 5645 5248 4854 4461 14375 8174 7737 7308 6887 6472 6064 566 5259 4861 4465 14125 8211 777 7338 6913 6495 6083 5675 5271 4869 4469 13875 8251 7806 737 6941 6519 6103 5691 5283 4878 4474 13625 8294 7845 7405 6972 6545 6125 5709 5297 4887 4479 13375 834 7886 7441 7004 6573 6148 5728 5311 4897 4484 13125 8388 793 748 7038 6603 6173 5748 5326 4907 449 12875 844 7977 7522 7075 6634 62 5769 5343 4918 4496 12625 8495 8026 7566 7114 6668 6228 5792 536 493 4502 12375 8553 8079 7613 7155 6703 6258 5816 5378 4943 4509 12125 8615 8135 7663 7199 6741 6289 5842 5398 4956 4517 11875 868 8194 7716 7245 6781 6323 5869 5418 4971 4524 11625 8749 8256 7771 7294 6823 6358 5898 544 4986 4532 11375 8822 8322 783 7346 6868 6396 5928 5463 5002 4541 11125 8899 8392 7892 7401 6915 6435 596 5488 5018 455 10875 898 8465 7958 7458 6965 6477 5994 5514 5036 456 10625 9066 8542 8027 7519 7018 6521 6029 5541 5055 457 10375 9155 8624 81 7583 7073 6568 6067 557 5075 4581 10125 925 8709 8177 7651 7131 6617 6107 56 5095 4592 9875 9349 8799 8257 7722 7193 6669 6149 5632 5117 4604 9625 9454 8894 8342 7797 7257 6723 6193 5665 514 4617 9375 9564 8994 8431 7875 7325 678 6239 5701 5165 463 9125 9679 9098 8525 7958 7397 684 6288 5738 519 4644 8875 98 9208 8624 8045 7472 6904 6339 5777 5217 4659 8625 9927 9324 8727 8137 7551 6971 6393 5819 5246 4674 8375 1006 9445 8836 8233 7635 7041 645 5862 5276 4691 8125 102 9572 895 8334 7722 7115 651 5908 5307 4708 7875 1035 9706 907 844 7814 7192 6573 5956 5341 4726 7625 105 9846 9197 8552 7911 7274 664 6007 5376 4745 7375 1066 9994 933 867 8014 7361 671 6061 5413 4766 7125 1083 1015 947 8794 8121 7452 6784 6118 5452 4787 6875 1101 1031 9617 8925 8235 7548 6862 6178 5494 481 6625 112 1049 9773 9063 8356 765 6945 6241 5537 4834 6375 114 1067 9937 9209 8483 7757 7033 6308 5584 4859 6125 1161 1086 1011 9364 8618 7872 7126 638 5634 4887 5875 1183 1106 103 9528 8761 7993 7225 6456 5686 4916 5625 1207 1128 1049 9703 8914 8123 7331 6537 5743 4947 5375 1231 1151 107 9889 9076 8261 7443 6624 5803 498 5125 1258 1175 1092 1009 925 8409 7564 6717 5867 5015 4875 1286 1201 1116 103 9436 8567 7694 6816 5936 5053 4625 1316 1229 1142 1053 9637 8738 7833 6924 601 5094 4375 1349 1259 1169 1078 9853 8922 7983 7039 609 5138 4125 1384 1292 1199 1104 1009 912 8146 7164 6177 5186 3875 1422 1327 1231 1133 1034 9336 8321 7299 627 5237 3625 1463 1365 1266 1165 1062 957 8512 7445 637 5291 3375 1508 1407 1304 1199 1092 9824 8719 7603 6479 middot535 3125 1557 1453 1346 1237 1124 101 8943 7773 6595 5412 2875 1612 1504 1393 1278 116 104 9185 7956 6719 5478 2625 1673 1561 1444 1323 1199 1073 9446 8152 6851 5546 2375 1741 1624 1501 1373 1242 1108 9725 8359 6989 5617 2125 1818 1695 1565 1429 1289 1146 1002 8575 713 5687 1875 1906 1775 1636 149 1339 1186 1032 8792 727 5755 1625 2007 1868 1716 1556 1392 1227 1062 9001 7401 5818
119
1375 1125 875 625 375 125
2127 2271 2449 2679 2994 3436
1975 2103 226
2467 2776 3361
1807 1912 2032 2173 2333 2469
1629 1707 1788 1863 191
1868
1447 1501 1548 1575 1559 1454
1266 1301 1324 1324 1279 1163
109 1111 112
1107 1058 9548
9183 9311 934
9205 8813 8043
7514 7591 7611 7544 735
6956
5873 5918 5953 5988 6049 6199
F6 Freezer Wall Simulation Output Including Anti-sweat Condenser Tube
INPUT PARAMETERS
Section Dimensions (mm) Width Length Depth Steel skin thickness Plastic skin thickness
5600 2000 1580 6500 2500
Mesh Geometry dx dy Number nodes in x-direction Number nodes in y-direction Number of steel skin nodes (including corner 00) Steel nodes under the seal Tube located at node
2800 2500 20 80
11 2 to 10 6
Steel skin conductivity (Wm K)
Foam insulation conductivity (Wm K) Plastic skin conductivity (Wm K)
Outside h (Wm2 K) Inside h (Wm2 K) Outside Temp (C) Inside Temp (C)
5400 27000E-02 1500 6870 6410 2100 -1000
OUPUT PARAMETERS
Number of iterations 879
ID Heat Flux Thru Wall (Wm2) 1362
Heat Transfer Along Metal Skin Under Seal node to node qm[Wm2] Qm[W]
2 3 -15024E+04 -1543 3 4 -15111E+04 -1552 4 5 -15205E+04 -1562 5 6 -15310E+04 -1572 6 7 5828 5986 7 8 5690 5844 8 9 5535 5684 9 10 5348 5492
Maximum difference (Is) 1356
j qleft[W] qright[W] -1 -1566 5928
120
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63
0 -62085E-02 -31363E-02 -5 9522E-02 -40097E-02 -44286E-02 -30955E-02 -33621E-02 -21814E-02 -25242E-02 -1 4577E-02 -1 8767E-02 -9 6252E-03 -13815E-02 -58162E-03 -10387E-02 -31499E-03 -73398E-03 -1 6265E-03 -54353E-03 -10285E-04
-35309E-03 27805E-04 -23882E-03 65891E-04 -16265E-03 14208E-03 -1 24 55E-03 14207E-03 -48371E-04 14207E-03 -10285E-04 10398E-03 -10285E-04 10399E-03 -10281E-04 10398E-03 -48371E-04 65891E-04 -1 02 85E-04 27805E-04 -86465E-04 16377E-04 -48375E-04 -52182E-04 -86465E-04 -97886E-04 -1 2455E-03 -13979E-03 -1 7788E-03 -16645E-03 -19692E-03 -21597E-03 -24263E-03 -25786E-03 -30357E-03 -30357E-03 -33404E-03 -35309E-03 -3 7975E-03 -3 9879E-03 -41784E-03 -44450E-03 -45974E-03 -49402E-03 -50164E-03 -53592E-03 -54353E-03 -58162E-03 -58543E-03 -62733E-03 -62733E-03 -66923E-03 -66542E-03 -71493E-03 -70351E-03 -75303E-03 -74541E-03 -7 9111E-03 -77969E-03 -83301E-03 -81397E-03 -87491E-03 -85206E-03 -90919E-03 -88634E-03 -94728E-03 -92062E-03 -97775E-03 -95109E-03 -10158E-02 -98537E-03 -10463E-02 -1 0158E-02 -10768E-02 -1 04 63E-02 -11073E-02 -10692E-02 -11377E-02 -10996E-02 -11644E-02 -11225E-02 -1 1949E-02 -11492E-02 -12215E-02 -11758E-02 -12444E-02 -11949E-02 -12672E-02 -12177E-02 -12901E-02 -12368E-02 -13129E-02 -12596E-02 -1 3282E-02 -12748E-02 -1 351 OE-02 -1 2977E-02 -13701E-02 -13129E-02 -1 3853E-02 -13282E-02 -14005E-02 -1 3434E-02 -14158E-02 -13586E-02 -14310E-02 -1 3701E-02 -14463E-02
121
64 -1 3815E-02 -1 4577E-02 65 -1 392 9E-02 -14691E-02 66 -14005E-02 -14767E-02 67 -14120E-02 -14881E-02 68 -14196E-02 -14958E-02 69 -1 4272E-02 -15034E-02 70 -14310E-02 -15110E-02 71 -1 4386E-02 -1 5148E-02 72 -14424E-02 -15186E-02 73 -14463E-02 -15224E-02 74 -14501E-02 -1 5262E-02 75 -14501E-02 -1 5300E-02 76 -14539E-02 -15262E-02 77 -14539E-02 -15300E-02 78 -1 4539E-02 -15262E-02 79 -14501E-02 -1 5300E-02
Qleft [Wj -1653 Qright [Wj 5163 Percent entering cabinet 2380
Freezer Nodal Temperatures (Condenser Tube)
x(mm) y(mm) 14 42 70 98 126 154 182 210 238 266
19875 9606 8457 7334 6235 516 4107 3075 2064 107 00944 19625 9596 8448 7325 6227 5152 4099 3068 2056 1064 00882 19375 9591 8443 732 6222 5148 4095 3064 2053 106 00850 19125 9591 8443 732 6222 5147 4095 3064 2052 106 00847 18875 9596 8448 7325 6226 5151 4099 3067 2056 1063 00873 18625 9606 8457 7334 6235 5159 4106 3074 2062 1069 00928 18375 9621 8472 7347 6248 5171 4118 3085 2072 1078 01013 18125 9641 8491 7366 6265 5188 4133 3099 2085 109 01128 17875 9666 8514 7388 6287 5208 4152 3117 2102 1106 01272 17625 9696 8543 7416 6313 5233 4176 3139 2123 1125 01447 17375 9731 8577 7448 6343 5262 4203 3165 2147 1147 01652 17125 9772 8616 7485 6378 5295 4234 3194 2174 1173 01888 16875 9817 8659 7526 6418 5333 427 3228 2206 1202 02156 16625 9868 8708 7573 6462 5375 431 3265 224 1234 02455 16375 9924 8762 7624 6511 5421 4353 3306 2279 127 02786 16125 9985 8821 7681 6565 5472 4402 3352 2322 131 03149 15875 1005 8885 7742 6624 5528 4454 3401 2368 1353 03546 15625 1012 8954 7809 6687 5588 4511 3455 2418 1399 03976 15375 102 9029 7881 6755 5653 4573 3513 2472 145 04441 15125 1029 911 7958 6829 5723 4639 3575 253 1504 0494 14875 1038 9196 804 6907 5798 4709 3641 2592 1562 05474 14625 1047 9287 8128 6991 5877 4784 3712 2659 1623 06045 14375 1057 9385 8221 708 5962 4865 3787 2729 1689 06652 14125 1068 9488 832 7175 6052 495 3868 2804 1759 07297 13875 1079 9597 8424 7275 6147 504 3952 2884 1833 07981 13625 1091 9713 8535 738 6247 5135 4042 2968 1911 08704 13375 1104 9834 8651 7491 6353 5235 4136 3056 1993 09466 13125 1117 9962 8774 7608 6464 534 4236 315 208 1027 12875 1131 101 8902 7731 6581 5451 434 3248 2172 1112 12625 1146 1024 9037 786 6704 5568 445 3351 2268 1201 12375 1161 1038 9178 7995 6833 569 4566 3459 2369 1294
122
12125 1177 1054 9326 8136 6967 5818 4686 3572 2475 1392 11875 1194 107 9481 8284 7108 5951 4813 3691 2585 1494 11625 1211 1087 9642 8439 7256 6091 4945 3815 2701 1602 11375 1229 1104 981 86 7409 6237 5083 3945 2822 1714 11125 1248 1122 9985 8768 757 639 5227 4081 2949 1832 10875 1268 1141 1017 8943 7737 6549 5378 4222 3082 1954 10625 1288 1161 1036 9125 7911 6714 5534 437 322 2083 10375 1309 1181 1055 9314 8092 6887 5698 4524 3364 2217 10125 1331 1203 1076 9511 8281 7067 5868 4685 3514 2356 9875 1354 1225 1097 9716 8477 7254 6046 4852 3671 2502 9625 1378 1248 1119 9929 8681 7448 6231 5026 3835 2654 9375 1402 1271 1142 1015 8893 7651 6423 5208 4005 2813 9125 1428 1296 1166 1038 9113 7861 6623 5398 4183 2979 8875 1454 1321 1191 1062 9342 808 6832 5595 4369 3152 8625 1481 1348 1216 1086 9579 8308 7049 5801 4562 3333 8375 1509 1375 1243 1112 9826 8545 7275 6015 4764 3522 8125 1538 1403 127 1139 1008 8791 751 6238 4975 3719 7875 1568 1432 1299 1166 1035 9047 7755 6472 5196 3925 7625 1598 1462 1328 1195 1063 9314 8011 6715 5426 4142 7375 163 1494 1358 1224 1091 9591 8278 697 5667 4368 7125 1663 1526 139 1255 1121 9881 8556 7236 5919 4606 6875 1697 1559 1422 1287 1152 1018 8847 7514 6184 4855 6625 1731 1593 1456 132 1185 105 9151 7806 6462 5118 6375 1767 1629 1491 1355 1218 1083 9469 8113 6755 5394 6125 1804 1665 1527 139 1254 1117 9804 8435 7063 5686 5875 1842 1703 1565 1428 129 1153 1015 8774 7388 5995 5625 1881 1742 1604 1466 1329 1191 1052 9133 7732 6322 5375 1921 1782 1644 1507 1369 1231 1091 9511 8097 6669 5125 1962 1824 1686 1549 1411 1272 1133 9913 8485 7039 4875 2004 1867 173 1593 1455 1317 1176 1034 8899 7435 4625 2047 1912 1776 164 1502 1363 1223 108 9341 7859 4375 2092 1958 1823 1688 1552 1413 1272 1128 9816 8315 4125 2138 2005 1873 1739 1604 1466 1325 1181 1033 8807 3875 2184 2055 1925 1793 166 1523 1382 1238 1088 934 3625 2232 2106 1979 1851 1719 1584 1444 1299 1148 992 3375 2282 216 2037 1911 1783 1649 1511 1366 1214 1055 3125 2332 2215 2097 1976 1851 1721 1584 1439 1286 1125 2875 2384 2273 2161 2045 1925 1798 1663 152 1366 1202 2625 2436 2334 2229 212 2005 1883 1751 1609 1455 1288 2375 249 2397 2301 22 2093 1976 1849 1708 1554 1384 2125 2546 2463 2377 2287 2188 2079 1957 182 1666 1493 1875 2602 2532 2459 238 2293 2193 2079 1946 1793 16 17 1625 266 2605 2546 2482 2407 232 2215 2089 1939 176 1375 2719 2681 264 2592 2533 2461 2369 2253 2108 1928 1125 2779 2761 2739 271 2671 2618 2543 244 2305 2128 875 2841 2844 2844 2838 2822 2792 2739 2655 2535 2367 625 2903 293 2954 2974 2986 2984 2959 2899 2802 2658 375 2967 3018 3069 3117 316 3194 3209 3173 3108 3009 125 3032 3108 3186 3263 3342 3421 35 347 344 3412
x (nun) y (nun) 294 322 350 378 406 434 462 490 518 546
19875 -0865 -1811 -2743 -3663 -4573 -5474 -6368 -7257 -8141 -9022 19625 -0871 -1816 -2747 -3667 -4577 -5477 -6371 -7259 -8142 -9024 19375 -0874 -1819 -275 -3669 -4578 -5479 -6372 -726 -8143 -9024 19125 -0874 -1819 -275 -367 -4579 -5479 -6372 -726 -8144 -9025 18875 -0872 -1817 -2748 -3668 -4577 -5478 -6372 -7259 -8143 -9025
123
18625 -0867 -1812 -2744 -3664 -4574 -5476 -637 -7258 -8142 -9024 18375 -0859 -1805 -2738 -3659 -457 -5472 -6366 -7256 -8141 -9023 18125 -0848 -1796 -273 -3652 -4563 -5466 -6362 -7252 -8139 -9022 17875 -0835 -1784 -2719 -3642 -4555 -546 -6357 -7248 -8136 -9021 17625 -0819 -1769 -2706 -3631 -4546 -5451 -635 -7243 -8132 -9019 17375 -0800 -1752 -2691 -3618 -4534 -5442 -6342 -7237 -8128 -9017 17125 -0779 -1733 -2673 -3602 -4521 -5431 -6334 -7231 -8124 -9014 16875 -0754 -1711 -2654 -3585 -4506 -5418 -6323 -7223 -8119 -9012 16625 -0727 -1686 -2632 -3565 -4489 -5404 -6312 -7214 -8113 -9009 16375 -0697 -1659 -2607 -3544 -447 -5389 -6299 -7205 -8106 -9005 16125 -0664 -1629 -258 -352 -445 -5371 -6286 -7194 -8099 -9001 15875 -0627 -1596 -2551 -3494 -4428 -5353 -6271 -7183 -8091 -8997 15625 -0588 -156 -2519 -3466 -4404 -5332 -6254 -717 -8083 -8993 15375 -0545 -1522 -2484 -3436 -4377 -531 -6236 -7157 -8074 -8988 15125 -0500 -148 -2447 -3403 -4349 -5287 -6217 -7143 -8064 -8983 14875 -0451 -1436 -2408 -3368 -4319 -5261 -6197 -7127 -8053 -8977 14625 -0399 -1388 -2365 -3331 -4287 -5234 -6175 -7111 -8042 -8971 14375 -0343 -1338 -232 -3291 -4253 -5206 -6152 -7093 -803 -8965 14125 -0284 -1284 -2272 -3249 -4216 -5175 -6127 -7074 -8017 -8958 13875 -0221 -1228 -2221 -3204 -4177 -5143 -6101 -7054 -8004 -8951 13625 -0155 -1168 -2168 -3157 -4137 -5108 -6073 -7033 -7989 -8943 13375 -0085 -1104 -2111 -3107 -4093 -5072 -6044 -7011 -7974 -8935 13125 -0011 -1037 -2051 -3054 -4048 -5034 -6013 -6987 -7958 -8927 12875 0065 -0966 -1988 -2998 -4 -4993 -598 -6963 -7941 -8918 12625 01474 -0892 -1922 -294 -3949 -4951 -5946 -6937 -7924 -8909 12375 0233 -0815 -1852 -2878 -3896 -4906 -591 -6909 -7905 -8899 12125 03229 -0733 -1779 -2814 -384 -4859 -5872 -688 -7885 -8888 11875 0417 -0648 -1702 -2746 -3782 -481 -5832 -685 -7865 -8877 11625 05157 -0558 -1622 -2675 -372 -4758 -5791 -6819 -7843 -8866 11375 06189 -0464 -1537 -2601 -3656 -4704 -5747 -6785 -7821 -8854 11125 07269 -0366 -1449 -2523 -3589 -4648 -5701 -675 -7797 -8841 10875 08398 -0263 -1357 -2441 -3518 -4588 -5653 -6714 -7772 -8828 10625 09577 -0156 -126 -2356 -3444 -4526 -5603 -6676 -7746 -8814 10375 1081 -0044 -116 -2267 -3367 -4461 -555 -6636 -7718 -88 10125 121 00732 -1054 -2174 -3286 -4393 -5495 -6594 -769 -8785 9875 1344 01957 -0943 -2076 -3202 -4322 -5437 -655 -766 -8769 9625 1484 03238 -0828 -1974 -3113 -4247 -5377 -6504 -7628 -8752 9375 1631 04575 -0708 -1867 -302 -4169 -5314 -6456 -7596 -8734 9125 1784 05974 -0582 -1755 -2923 -4087 -5247 -6405 -7561 -8716 8875 1944 07436 -0450 -1638 -2822 -4001 -5178 -6352 -7525 -8697 8625 2111 08966 -0312 -1516 -2715 -3911 -5105 -6296 -7487 -8676 8375 2286 1057 -0167 -1387 -2604 -3817 -5028 -6238 -7447 -8655 8125 2469 1224 -0015 -1253 -2486 -3718 -4948 -6177 -7405 -8633 7875 2661 14 0143 -1111 -2363 -3614 -4863 -6112 -736 -8609 7625 2861 1584 031 -0962 -2234 -3504 -4774 -6044 -7314 -8584 7375 3072 1778 04856 -0806 -2097 -3389 -468 -5972 -7265 -8558 7125 3293 1982 06704 -0641 -1954 -3267 -4581 -5896 -7213 -853 6875 3526 2196 08652 -0467 -1802 -3138 -4476 -5816 -7158 -8501 6625 3771 2422 1071 -0283 -1641 -3002 -4366 -5732 -71 -847 6375 403 2661 1288 -0089 -1471 -2858 -4248 -5642 -7038 -8437 6125 4303 2914 1519 01168 -1291 -2705 -4124 -5547 -6973 -8402 5875 4593 3182 1763 03357 -11 -2542 -3991 -5445 -6904 -8365 5625 49 3467 2023 05686 -0896 -2369 -385 -5338 -683 -8326 5375 5227 3771 23 08169 -0678 -2185 -37 -5223 -6751 -8284 5125 5576 4095 2596 1082 -0446 -1988 -354 -5101 -6668 -8239 4875 5949 4442 2913 1366 -0198 -1778 -337 -4971 -6579 -8193 4625 635 4814 3254 167 00669 -1553 -3187 -4832 -6485 -8143 4375 6781 5215 3619 1997 03519 -1313 -2993 -4685 -6385 -809
124
4125 7246 5647 4014 2349 06577 -1055 -2785 -4528 -6279 -8036 3875 775 6116 444 2728 0986 -0780 -2565 -4362 -6168 -7978 3625 8299 6625 4902 3137 1339 -0486 -233 -4187 -6051 -7919 3375 8899 718 5404 3579 1717 -0173 -2082 -4003 -593 -7859 3125 9558 7787 595 4057 2122 01586 -1823 -3813 -5806 -7798 2875 1028 8455 6545 4573 2555 0508 -1553 -3618 -568 -7739 2625 1109 9192 7197 513 3014 0872 -1277 -3422 -5558 -7683 2375 12 1001 7912 5729 3497 1245 -1002 -3233 -5442 -7633 2125 1301 1093 8698 6373 3998 1618 -0739 -3059 -534 -7592 1875 1418 1196 9566 7058 4508 1975 -0503 -2914 -5262 -7564 1625 1552 1314 1053 778 5007 2292 -0319 -2818 -5218 -7554 1375 171 1452 116 8525 5462 2528 -0224 -2798 -5226 -7564 1125 19 1616 1281 9263 5815 2621 -0272 -2892 -5304 -7597 875 2136 182 1417 9928 5968 2477 -0537 -3151 -5478 -7651 625 244 2095 1569 1037 575 1953 -112 -3637 -5773 -7713 375 2845 2514 1726 1027 4873 0854 -2146 -4427 -6224 -7757 125 3384 3296 1814 8879 2904 -1057 -3745 -5602 -6885 -7725
F bull 7 Seal Simulation Source Code and Ouput
Program Seal
c This program simulates the heat transfer characteristics of an c idealized refrigerator door gasket The steady-state temperature c profile is determined numerically from a 2-D finite difference c code
cxxxxxxxxxxxxx Parameters and Variablesxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
integer NNNWnsurfijjlloopiters real emmissigmakhihoTiTodelsNN real depthareatolkair
parameter (N=6) parameter (NN=20) parameter (W=7) parameter (nsurf=4N-l) parameter (emmis=09) parameter (sigma=567e-8) parameter (k=03) parameter (kair=0026) parameter (hi=641) parameter (ho=687) parameter (Ti=1032) parameter (To=209) parameter (sNN=02) parameter (del=sNNNN) parameter (depth=10) parameter (area=deldepth) parameter (tol=10)
real x(Onsurf)y(Onsurf)len(ONOnsurf) real F(OnsurfOnsurf) real T(-lNN+lONN)radl(nsurf+l)rad(Onsurf) real Eb(Onsurf)bvector(nsurf+l)Amatrix(nsurf+lnsurf+l) real difasumqsumqtotqin(NN-l) real rlr2r3r4r5
125
real clc2c3c4c5c6c7
open (lfilemiddotGasketoutposition-rewind) open (2file=Gasket(q)outpositionmiddotrewind)
cxxxxxxxxxxxxx Determine Viewfactors xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
call Points(Ndelnsurfxy) call length(Ndelnsurfxylen) call Vfactor(NdelnsurflenF)
cxxxxxxxxxxxxx Resistors (C-m2W)
c Interior x- and y-directions rl=delk
c Exterior to outdoor ambient r2=1ho
c Exterior to indoor ambient r3-1hi
c Radiation r4=(1-emmis)emmis
c Air r5=delkair
xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
cxxxxxxxxxxxxx Guass-Siedel Iteration xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
c Begin massive loop to determine the steady-state temperature c distribution across the section First update the interior nodes c by considering the radiative heat transfer among the interior c surfaces The radiative transfer is updated by calling a routine c which computes the new radiosities every iteration Loop until c tolerance is met
c Initialize temperature field do 10 i=ONN
do 11 jONN T(ij)=50
11 continue 10 continue
do 15 j=ONN T(-1j)=250 T(NN+lj)=50
15 continue
c Set temperatures for row y=O and row y=NN do 20 i=ONN
T(iO)=fl(idel) T(iNN)=f2(idel)
20 continue
cxxxxxxxxxxxxx Begin Iteration xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
loop=l iters=l do while (loop eq 1)
c Update radiosities using new temps and update interior surface nodes
call Jsolver(FemmissigmaTNNNWnsurfradlradEb + bvectorAmatrix)
c interior corners cl=area (2rl) c2=arearl
126
c3=area (2rl) c4=arearl c5=arear4 c6=1(cl+c2+c3+c4)
T(WW)=c6(clT(W+lW)+c2T(W-lW)+c3T(WW+l)+ + c4T(WW-l)+c5(rad(0)-Eb(0raquo)
cl=arearl c2=area(2rl) c3=area(2rl) c4=arearl c5=arear4 c6-1(cl+c2+c3+c4) T(W+NW)=c6(clT(W+N+lW)+c2T(W+N-lW)+c3T(W+NW+l)+
+ c4T(W+NW-l)+c5(rad(N)-Eb(Nraquo) clarearl c2-area (2rl) c3-arearl c4=area(2rl) c5=arear4 c6=1(cl+c2+c3+c4) T(W+NW+N)=c6 (clT(W+N+lW+N)+c2T(W+N-lW+N) +c3T(W+NW+N+l)+
+ c4T(W+NW+N-l)+c5(rad(2N)-Eb(2Nraquo) cl=area(2rl) c2=arearl c3=arearl c4=area(2rl) c5=arear4 c6=1(cl+c2+c3+c4) T(WW+N)=c6 (clT(W+lW+N) +c2T(W-lW+N)+c3T(WW+N+l) +
+ c4T(WW+N-l)+c5(rad(3N)-Eb(3Nraquo)
c Interior surface y=W jl=l do 22 i=W+lW+N-l
cl=area(2rl) c2=area (2rl) c4=arearl c5=arear4 c7=arear5 c6=1(cl+c2+c4+c7) T(iW)=c6(clT(i+lW)+c2T(i-lW)+
+ c7T(iW+l)+c4T(iW-l)+c5(rad(jl)-Eb(jlraquo) jl=j1+1
22 continue
c Interior surface y=N+W jl=3N-l do 25 i=W+lW+N-l
cl=area(2rl) c2=area (2rl) c3=arearl c5=arear4 c7=arear5 c6=1(cl+c2+c3+c7) T(iW+N)=c6(clT(i+lW+N)+c2T(i-lW+N)+
+ c7T(iW+N-l)+c3T(iW+N+l)+c5(rad(jl)-Eb(jlraquo) jl=jl-l
25 continue
c interior surface x=W jl=4N-l do 30 j=W+lW+N-l
c2=arearl
127
c3=area (2rl) c4=area(2rl) c5-arear4 c7-arear5 c6-1(c2+c3+c4+c7) T(Wj)-c6(c7T(W+lj)+c2T(W-lj)+c3T(Wj+l)+
+ c4T(Wj-l)+c5(rad(jl)-Eb(jl))) jl=jl-l
30 continue
c interior surface x=W+N jl=N+l do 35 j-W+lW+N-l
cl=arearl c3=area(2rl) c4=area (2rl) c5-arear4 c7-arear5 c6-1(cl+c3+c4+c7) T(W+Nj)=c6(clT(W+N+lj)+c7T(W+N-lj)+c3T(W+Nj+l)+
+ c4T(W+Nj-l)+c5(rad(jl)-Eb(jl))) jl=j1+1
35 continue
c Interior air nodes do 37 j=W+lN+W-l
do 38 i=W+lN+W-l call sseqn(Tr5r5r5r5areaareaareaareaijNN)
38 continue 37 continue
c Solid nodes do 40 i=lNN-l
do 45 jlW-l call sseqn(TrlrlrlrlareaareaareaareaijNN)
45 continue do 50 j=W+N+lNN-l
call sseqn(TrlrlrlrlareaareaareaareaijNN) 50 continue 40 continue
do 55 j=WW+N do 60 i=lW-l
call sseqn(TrlrlrlrlareaareaareaareaijNN) 60 continue
do 65 i=W+N+lNN-l call sseqn(TrlrlrlrlareaareaareaareaijNN)
65 continue 55 continue
c Side boundaries do 70 j=lNN-l
call sseqn(Trlr2rlrlareaareaarea2area20jNN) call sseqn(Tr3rlrlrlareaareaarea2area2NNjNN)
70 continue
c Apply energy balance around the boundary of the gasket to determine c stopping criterium dif
dif-OO dif=dif+(area(2rl))(T(00)-T(01)) dif=dif+(area(2rl))(T(0NN)-T(0NN-l)) do 90 i=lNN-l
dif=dif+(arearl)(T(iO)-T(il)) dif=dif+(arearl)(T(iNN)-T(iNN-l))
128
90 continue dif=dif+(area(2r1raquo(T(NN0)-T(NN1raquo dif=dif+(area(2r1raquo(T(NNNN)-T(NNNN-1raquo
do 95 j=1NN-1 dif=dif+(arear2)(To-T(0jraquo dif-dif+(arear3)(Ti-T(NNjraquo
95 continue
print dif
c Stopping criterium if (dif It toll then
loop-O endif if (iters eq 10000) then
loop=O endif
iters=iters+1 end do
cxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx c Compute heat flux into the cabinet
qsum=OO asum=OO do 97 j=1NN-1
qin(j)=hiarea(T(NNj)-Ti) qsum=qsum+qin(j) asum=asum+area
97 continue qtot=qsumasum write(2) heat flux to interior [Wm2)qtot
do 100 j=NNO-l write(l) (T(ij)i=ONN)
100 continue
pause stop end
c----------------------------------------------------------------------shyc------~----------------------------------------------------------------
Subroutine Points(Ndelnsurfxy)
integer Nnsurfi real delincrx(Onsurf)y(Onsurf)
x(O)=OO y(0)=del2
c Points along y=O edge incr-OO do 10 i=lN
y(i)=OO x(i)=(del2)+incr incr=incr+del
10 continue
c Points along x=Ndel edge incr=OO do 20 i=N+12N
x(i)=Ndel
129
y(i)-(del2)+incr incr-incr+del
20 continue
c Points along y=Ndel edge incr=OO do 30 i=3N2N+l-1
y(i)-Ndel x(i)=(del2)+incr incr-incr+del
30 continue
c Points along x-O edge incr=OO do 40 i-nsurf3n+l-1
xli) -00 y(i)-laquo3del)2)+incr incr-incr+del
40 continue
return end
c----------------------------------------------------------------------shyc-----------------------------------------------------------------------
Subroutine length(Ndelnsurfxylen)
integer Nnsurfij real dellen(ONOnsurf)x(Onsurf)y(Onsurf)
c Special case surface 0 do 10 j=Onsurf
len(0j)=sqrtlaquox(0)-x(jraquo2+(y(0)-y(jraquo2) 10 continue
c Surfaces along y=O do 20 i=IN-l
do 30 j=Onsurf len(ij)=sqrtlaquox(i)-x(jraquo2+(y(i)-y(jraquo2)
30 continue 20 continue
c Special case surface N do 50 j=Onsurf
len(Nj)=sqrtlaquox(N)-x(jraquo2+(y(N)-y(jraquo2) 50 continue
return end
c----------------------------------------------------------------------shyc-----------------------------------------------------------------------
Subroutine Vfactor(NdelnsurflenF)
integer Nnsurfijjlj2 real dellen(ONOnsurf)F(OnsurfOnsurf)Lzero
c Determine viewfactors for special case of surface 0 Lzero=delsqrt(20) do 10 j=Onsurf
if (j eq 0) then F(Oj)=OO
elseif (j eq nsurf) then F(Oj)=(len(Oj)+len(10)-len(00)-len(ljraquo(2Lzero)
else F(0j)=(len(0j)+len(lj+l)-len(Oj+l)-len(ljraquo(2Lzero)
130
endif 10 continue
c Determine viewfactors for surfaces on edge y-O
do 20 i=IN-l do 30 j=Onsurf
if (i eq j) then F(ij)=OO
elseif (j eq nsurf) then F(ij)=(len(ij)+len(i+l0)-len(i0)-len(i+ljraquo(2de1)
else F(ij)=(len(ij)+len(i+lj+l)-len(ij+l)-len(i+ljraquo(2del)
endif sum=sum+F(ij)
30 continue 20 continue
c Determine viewfactors for all other surfaces do 40 iON-l
do 50 j=03N-l F(i+Nj+N)=F(ij)
50 continue do 60 j=3Nnsurf
F(i+Nj-3N)=F(ij) 60 continue
do 70 j=02N-1 F(i+2Nj+2N)=F(ij)
70 continue do 80 j=2Nnsurf
F(i+2Nj-2N)=F(ij) 80 continue
do 90 j=ON-l F(i+3Nj+3N)=F(ij)
90 continue do 100 j=Nnsurf
F(i+3Nj-N)=F(ij) 100 continue
40 continue
return end
c----------------------------------------------------------------------shyc-----------------------------------------------------------------------
Subroutine Jsolver(FemmissigmaTNNNWnsurfradlradEb + bvectorAmatrix)
integer NNNnsurfij real emmissigmaF(OnsurfOnsurf) real T(-INN+10NN)rad1(nsurf+l)rad(0nsurf) real Eb(0nsurf)bvector(nsurf+1)Amatrix(nsurf+lnsurf+l)surn
c Compute Eb for all surfaces do 10 i-ON-l
Eb(i)=sigma(T(i+WW) 4) Eb(i+N)=sigma(T(W+Ni+W)4)
10 continue incr=W+N do 20 i=0N-1
Eb(i+2N)=siqrna(T(incrW+N) 4) Eb(i+3N)=sigma(T(Wincr)4) incr=incr-1
20 continue
131
c Assign values to vector b do 30 i=Onsurf
bvector(i+l)-(emmis(l-emmisraquoEb(i) 30 continue
c Assign values to matrix A do 40 i-Onsurf
do SO j=Onsurf Amatrix(i+lj+l)--F(ij)
SO continue 40 continue
c Override diagonal terms do 60 i-Onsurf
sum-OO do 70 j-Onsurf
sum-sum+F(ij) 70 continue
Amatrix(i+li+l)-(emmis(l-emmisraquo+sum 60 continue
c Call routine to solve the set of equations for unknown JS call gaussy(Amatrixbvectorradlnsurf+l)
do 80 i=Onsurf rad(i)=radl(i+l)
80 continue
return end
c----------------------------------------------------------------------shyc-----------------------------------------------------------------------
Subroutine Gaussy(abxn) c
integer nkiimaxjkplusllplus real a(nn)b(n)x(n)amaxbtempatemp
+ aeon sum
do 28 k=l n amax=OO do 4 i=kn if(abs(a(ikraquo-abs(amaxraquo442
2 amax=a(ik) imax=i
4 continue if(abs(amax)-0le-15)101014
10 printO equations are not independent return
14 btemp=b(k) b(k)=b(imax) b(imax)=btemp do 18 j=kn
atemp=a(k j) a(kj)=a(imaxj)
18 a(imaxj)=atemp kplus=k+l if(k-n)222828
22 do 24 i=kplusn b(i)=b(i)-b(k)a(ik)a(kk) acon=a(ik) do 24 j=kn
24 a(ij)=a(ij)-a(kj)acona(kk) 28 continue
132
l=n 32 sum=OO
if(1-n)343838 34 lplus-1+1
do 36 j-lplusn 36 sum=sum+a(lj)x(j) 38 continue
x(l)-(b(l)-sum)a(ll) if(1-1)424240
40 1-1-1 goto 32
42 return end
c----------------------------------------------------------------------shyc-----------------------------------------------------------------------
Subroutine sseqn(TriplusriminusrjplusrjminusAiplus + AiminusAjplusAjminusijNN)
c This subroutine computes the temperature at node (ij) c given the temperatures of the surrounding nodes and c the resistances leading to these nodes
integer ijNN real T(-1NN+10NN)riplusriminusrjplusrjminus real AiplusAiminusAjplusAjminus real c1c2c3c4c5
c1=Aiplusriplus c2=Aiminusriminus c3=Ajplusrjplus c4=Ajminusrjminus c5=1(c1+c2+c3+c4)
T(ij)=c5(c1T(i+1j)+c2T(i-1j)+c3T(ij+1)+c4T(ij-1raquo
return end
c----------------------------------------------------------------------shyc----------------------------------------------------------------------shy
real function f1(x) c door BC
real x f1-18520 - 23413x
return end
c----------------------------------------------------------------------shyc----------------------------------------------------------------------shy
real function f2(x) c wall BC
real x f2=18128 - 3475x
return end
c----------------------------------------------------------------------shyc----------------------------------------------------------------------shy
133
Fresh Food Compartment Simulations Results
Run 1 The prescribed temperature profiles are
Wall 19203 - 1908 x Door 19203 - 1206 x
(x is in meters)
Outdoor Ambient = 210 degC Local Indoor Ambient = 1533 degC
Run 2 The prescribed temperature profiles are
Wall 18989 - 2024 x Door 19078 - 1326 x
(x is in meters)
Outdoor Ambient = 210 degC Local Indoor Ambient = 1496 degC
Run 3 The prescribed temperature profiles are
Wall 1895 - 1998 x Door 19053 - 1384 x
(x is in meters)
Outdoor Ambient = 208 degC Local Indoor Ambient = 1491 degC
Ayem~ Values Wall 1905 - 1977 x Door 1913 - 1384 x
(x is in meters)
Ave Outdoor Ambient = 209 degC Ave Local Indoor Ambient =1507 degC
Loss from Fresh Food == 10 W
134
Freezer Compartment Simulations Results
Run 1 The prescribed temperature profiles are
Wall 1821 - 343 x Door 18606 - 2354 x
(x is in meters)
Outdoor Ambient = 210 degC Local Indoor Ambient = 1029 degC
Run 2 The prescribed temperature profiles are
Wall 18182 - 3542 x Door 18544 - 2398 x
(x is in meters)
Outdoor Ambient = 210 degC Local Indoor Ambient = 1042 degC
Run 3 The prescribed temperature profiles are
Wall 17993 - 3452 x Door 18411 - 2272 x
(x is in meters)
Outdoor Ambient = 208 degC Local Indoor Ambient = 1024 degC
Ayera~e Values Wall 18128 - 3475 x Door 18520 - 23413 x
(x is in meters)
Ave Outdoor Ambient = 209 degC Ave Local Indoor Ambient = 1032 degC
Loss from Fresh Food = 157 W
135
T ABLE OF CONTENTS
Page
LIST OF TABLESvii
LIST OF FIGURES viii
1 INTRODUCTION 1
2 LITERATURE REVIEW5
3 ONE-DIMENSIONAL WALL AND DOOR LOADS 7
31 One-dimensional Heat Transfer ModeL 7 32 Determination of Effective Heat Transfer Coefficients 8 33 Results 10
4 EXPERIMENTAL ANAL YSIS 12
41 Temperature Profile Measurements 12 42 Thermopile Testing 14 43 Thermocouple Drag Testing 16 44 Experimental Determination of qwall and qdoor 19 45 Experimental Determination of qmulloff 21 46 Experimental Determination of qmullon 24 47 Determination of qmisc 27
5 NUMERICAL SIMULATION28
51 Wall Model 28 52 Wall Simulation to Determine qwall 32 53 Wall Edge Simulation to Determine qtube 36 54 Door Seal Simulation to Determine qseal 40
6 DISCUSSION OF RESULTS 46
61 Comparison of Simulation Results with Experimental Data 48 62 Mullion Analysis 49 63 Seal Analysis 49 64 Anti-sweat Condenser Tube Analysis 49 65 Overall Cabinet Load 50
7 SUMMARY OF CONCLUSIONS 54
REFERENCES 55
v
TABLE OF CONTENTS (CONTINUED)
Page APPENDIX A FUMED SILICA INVESTIGATION 56
Al Introduction56 A2 Thermal Properties 56 A3 Experimental Method 57 A4 Theory57 A5 Test Apparatus 59 A6 Results 61 A7 Conclusions 65 A8 Thermal Diffusivity Newton-Raphson Iteration Source Code 65
APPENDIX B ONE-DIMENSIONAL SIMULATION SOURCE CODE AND OUTPUT 69
Bl Source Code 69 B2 Output 71
APPENDIX C TEST REFRIGERATOR DESCRIPTION 73
APPENDIX D DATA ACQUISITION AND CONTROL SYSTEM 77
APPENDIX E EXPERIMENTAL DATA AND PLOTS 79
El Temperature Profile Plots From Fixed Thermocouples 79 E2 Thermopile Data Reduction 81 E3 Experimental Determination of qwall and qdoor Details 82 E4 Temperature Profile Plots From Mullion Data (Heater Off) 84 E5 Temperature Profile Plots From Mullion Data (Heater On) 87
APPENDIX F NUMERICAL SIMULATION EQUATIONS AND CODE 92
Fl Finite-Difference Equations 92 F2 Wall Simulation Source Code 94 F3 Fresh Food Wall Simulation Output 102 F4 Freezer Wall Simulation Output 108 F5 Fresh Food Wall Simulation Output Including
Anti-sweat Condenser Tube 115 F6 Freezer Wall Simulation Output Including
Anti-sweat Condenser Tube 120 F7 Seal Simulation Source Code and Output 125
vi
LIST OF TABLES
Page
31 One-dimensional Model Parameters 8 32 Results from One-dimensional Load Analysis 10
41 Thermopile Output 16 42 Experimental Determination of qwall and qdoor 20 43 Experimental Results from Mullion Analysis 24 44 Experimental Results from Heater Analysis 26 45 Miscellaneous Loads 27
51 Wall Simulation Input 30 52 Input Values 32 53 Wall Simulation Results 33 54 Wall With Condenser Tube Simulation Results 36 55 Seal Simulation Input 42 56 Seal Simulation Results 43
61 Comparison of Simulation and Experimental Values for qwall and qdoor 48 62 Overall Cabinet Loads 51
A1 Average Fumed Silica Conductivity for Various Bulk Densities 63 A2 Average Fumed Silica Diffusivity for Various Bulk Densities 64
E1 Thermopile Raw Data 82
F1 Model Resistors 92
V1l
LIST OF FIGURES
Page 11 Door Seal Region Cross Section 3 12 Mullion Region Cross Section 4
31 Model Used To Calculate One-dimensional Load 7
41 SteelSkin Temperature Profile Thermocouple Placement 12 42 Steel Skin Temperature Plot for Fresh Food Compartment 13 43 Steel Skin Temperature Plot for Freezer 14 44 Thermopile Test Apparatus 15 45 Thermopile Placement ~ 16 46 Thermocouple Drag Test Apparatus 17 47 Drag Profiles (Fresh Food) 18 48 Drag Profiles (Freezer) 19 49 Heat Flow Paths in Mullion 21 410 Mullion Face Plate Cross Section 22 411 Mullion Temperature Profile 23 412 Electric Heater Location 25 413 Mullion Temperature Profile With Heater On (Center) 26
51 Wall Heat Conduction Model Sketch 29 52 Non-adiabatic Door Seal 31 53 Fresh Food Wall Temperature Distribution 34 54 Freezer Wall Temperature Distribution 35 55 Tube Location for Simulation 36 56 Fresh Food Wall Temperature Distribution
Including Warm Anti-sweat Tube 37 57 Freezer Wall Temperature Distribution
Including Warm Anti-sweat Tube 38 58 Load Due to Condenser Tube for Various Tube Placements 39 59 ~ercentage of Heat Entering Cabinet for Various Tube Placements 39 510 Seal Simulation Mesh Layout 40 511 Seal Cavity Mesh Details 41 512 Seal Temperature Distribution (Fresh Food) 44 513 Seal Temperature Distribution (Freezer) 45
61 Refrigerator System Load Graph 46 62 Cabinet Loads Graph 47
A1 Fumed Silica Test Apparatus 59 A2 Fumed Silica Test Facility Schematic 60 A3 Time vs Temperature for Unpacked Run 61 A4 Natural Log Time vs Temperature for Unpacked Run 62 A5 Conductivity vs Bulk Density 63 A5 Diffusivity vs Bulk Density 64
viii
LIST OF FIGURES (CONTINUED)
Page
C1 Location of Anti-sweat Devices and Overall Dimensions of Test Refrigerator 73
C2 Fresh Food Compartment Interior Dimensions 74 C3 Fresh Food Door75 C4 Freezer Interior Dimensions 76 C5 Freezer Door76
D1 Data Acquisition and Control System 78
E1 Steel Skin Temperature Plot for Fresh Food Compartment (Run 2) 79 E2 Steel Skin Temperature Plot for Fresh Food Compartment (Run 3) 80 E3 Steel Skin Temperature Plot for Freezer (Run 2) 80 E4 Steel Skin Temperature Plot for Freezer (Run 3) 81 E5 Mullion Temperature Profile Run 2 (Heater Off) 84 E6 Mullion Temperature Profile Run 3 (Heater Off) 85 E7 Mullion Temperature Profile Run 4 (Heater Off) 85 E8 Mullion Temperature Profile Run 5 (Heater Off) 86 E9 Mullion Temperature Profile Run 2 (CenterHeater On) 87 E10 Mullion Temperature Profile Run 3 (CenterHeater On) 88 E11 Mullion Temperature Profile Run 1 (LeftHeater On) 88 E12 Mullion Temperature Profile Run 2 (LeftHeater On) 89 E13 Mullion Temperature Profile Run 3 (LeftHeater On) 89 E14 Mullion Temperature Profile Run 1 (RightHeater On) 90 E15 Mullion Temperature Profile Run 2 (RightHeater On) 90 E16 Mullion Temperature Profile Run 3 (RightHeater On) 91
F1 Generic Nodal Resistor Network 92
IX
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1 INTRODUCTION
New regulations recently announced by the Department ofEnergy call for substantial
energy efficiency increases for household appliances by 1993 The refrigerator is of
particular interest since it is the largest household consumer of electricity and accounts for a
large part of the 8 of the electricity used in the US for food-cooling both residential and
commercial In addition to efficiency standards regulations are being imposed on the use
of CFCs completely banning their use by the year 2000 (Braswell 1988)
The objective of this thesis is to present an analysis of all heat transfer paths from the
surroundings to the interior food compartments of the refrigerator under closed door
conditions Both experimental and numerical methods are used as a means to determine the
overall cabinet load as well as the load due to each pathway The study is focused on a
particular unit for practical purposes However the methods implemented may be applied
to any make or model to aid in the search for high efficiency cabinets
All loads determined in this study are strictly cabinet loads and not the loads seen by the
refrigerator system The thermal load on the cabinet is comprised of three main parts (i)
the load due to the one-dimensional heat transfer through the walls and doors to the food
compartments away froin the edges (ii) the load due to edge effects that is heat transfer
into the food storage compartments via paths around the perimeter of the cabinet aperture
and (iii) other miscellaneous sources
(11)
The determination of qlD is straightforward and is discussed in detail in Chapter 3 The
edge load must be broken down into several parts for examination
qedge = qwall + qdoor + qseal + qrnullon + qtubeave (12)
where
qwall heat input due to conduction along the wall steel flange
qdoo heat input due to conduction along the door steel flange
qseal heat conduction directly through the door seal
1
heat input due to conduction in the mullion region with the additional input from an anti-sweat heater
qtubeave heat input due to cabinet anti-sweat condenser tube averaged over the cycle time
heat input due to cabinet anti-sweat condenser tube
heat input due to conduction in the mullion region electric heater off
It is assumed that an electric anti-sweat heater in the mullion region is in use for the entire
cycle The test unit chosen for this study required this region to be heated almost
continually to eliminate condensation This load is represented by qmulloo in Eq (12)
The load qmulloff is due to heat conduction to the interior compartments at the mullion
region when the electric heater is off Although this value does not appear in the edge load
definition it is still important to detennine for sake of comparison with the value of
qmulloo The load due to the presence of an anti-sweat condenser loop around the aperture
of the cabinet is defmed as qtube Since this load is present for the on cycle only it must be
integrated over the cycle time to be included in Eq (12) hence the tenn qtubeave
The tenn qroisc is expressed as
qmisc = qfanave + qdefrostave + qcompave (13)
where
qfanave heat input from the evaporator fan averaged over the cycle time
qdefrostave heat input from the defrost heaters averaged over defrost cycle time
qcompave heat input from elevated exterior walls near the running compressor
Figure 11 is a cross sectional drawing of the door seal area of the test refrigerator
examined to detennine qwalI qdoor and~ The figure includes materials and their
properties taken from Incropera and Dewitt (1985)
2
400 ~I-I~ 065~
065 Only dimension that is different for the freezer
200
kltWIm-K)
Outer Steel Skin 540 312~ Polyurethane Wall Insulation 0027 0015- Inner Plastic Skin 015 009~
~ Rubber Gasket 03 017fm1I ~ ~ Glass Fiber Door Insulation 004 0023
All dimensions in millimeters
1 in= 254mm
Fig 11 Door Seal Region Cross Section
3
Figure 12 is a drawing of the mullion region cross section of the test refrigerator examined
to detennine ltlmullon and ltlmulloff
FREEZER
Freezer Gasket
Fresh Food Gasket
FRESH FOOD COMPARTMENT
Fig 12 Mullion Region Cross Section
The remainder of this thesis is devoted to the analysis of the closed door cabinet loads and
the experimental and numerical techniques used for their detennination
An experimental investigation of fumed silica as an alternative insulation for the refrigerator
is presented in Appendix A Although this appears to be a departure from the main topic
a relation exists The desire of higher efficiency requires a search for equal if not better
cabinet insulations that do not incorporate the use of ozone damaging CFCs Testing is
done to detennine the thennal conductivity and diffusivity of fumed silica for several
densities
4
2 LITERATURE REVIEW
The new energy standards imposed by the Department ofEnergy have sparked research in
the area of refrigerator efficiency and alternative refrigerants A study by Turiel and
Heydari (1988) focused on several ways to improve the efficiency of refrigerator-freezers
and freezers
Various classes for the study were chosen however the paper presents extensive results for
the most common variety a top-mounted automatic defrost refrigeratorfreezer The
design options considered were those changes that can be incorporated into the existing
refrigerator design Two types of improvements are noted (i) changes that increase energy
efficiency by decreasing the heat transfer into the cabinet and (ii) changes that increase the
efficiency by reducing auxiliary electricity use or improving the refrigeration system Type
(i) changes include Foam insulation substitution increased insulation thickness double
door gaskets improved foam insulation evacuated insulation panels and reduced heat load
of through-the-door feature Type (ii) changes include High efficiency compressor
substitution adaptive defrost fan and fan motor improvement anti-sweat heater switch
increased evaporator surface area hybrid evaporator enhanced heat transfer surfaces
mixed refrigerants improved expansion valve fluid control valve two-compressor system
use of natural convective currents and location of compressor condenser and evaporator
fan motor
Turiel and Heydari used a model developed by Little (1982) to carry out the energy use
simulations This model is a steady-state energy use simulation which computes the heat
leakage to the cabinet and then determines the energy needed to maintain the interior
ambient temperatures dictated by the OOE test procedure Turiel and Heydari present the
energy consumption figures for a 18 cubic foot top-mounted automatic defrost
refrigeratorfreezer as a baseline case They find that 74 of the total energy is accounted
for by the compressor 11 is for the anti-sweat heaters 10 is for the fans and 5 is
for the defrost heaters for a total of 947 kWhyr Also about 10 of the compressor
energy use is for the removal of internal heat generated by the evaporator fan motor defrost
heater and anti-sweat heaters
Several subsequent simulations were performed each time adding a design option that was
projected to improve efficiency The improvement levels were added cumulatively and
results were given on compressor run time heat leakage rate into the cabinet compressor
5
power demand at the operating point fan motor operating power for the evaporator and
condenser fans anti-sweat heater power and total daily and annual energy consumption
The goal here was to achieve by the last level of improvement the minimum energy
consumption that is technologically feasible One important fmding for all product classes
tested the highest efficiency was obtained by the use of evacuated panels in the planar
walls For example for the top-mounted automatic defrost unit the minimum energy use
was 515 kWyr
Finally an energy usevolume relation was developed from a linear regression obtained
from simulation results The resulting fit was shown as
Energy Use = Cl + C2Adjusted Volume
The constant Cl indicates the direct energy use to remove the cabinet loads associated with
the fan motors and heaters The slope C2 is an indicator of the rate of change ofenergy use
with a change in the adjusted volume This value reflects the rate of cabinet heat gain The
adjusted volume is the volume of the fresh food compartment plus 163 times the volume
of the freezer Turiel and Heydari produced a series of regressions for all of the defined
levels of design improvements allowing easy comparison at a specific adjusted volume
6
3 ONE-DIMENSIONAL WALL AND DOOR LOADS
In this section the overall steady cabinet load is calculated without considering the addition
of edge loading This load qlD is dermed as the heat transfer from the exterior
environment to the interior of the refrigerator under nonnal closed-door operating
conditions through four primary conductive paths (i) fresh food compartment walls (ii)
freezer walls (iii) fresh food door and (iv) freezer door In a later chapter the load due to
edge loading will be examined more closely
31 One-dimensional Heat Transfer Model
The steady conductive heat transfer through the walls of the refrigerator cabinet is
computed using a simple computer program written by Qausing (1983) This program
estimates inside and outside effective heat transfer coefficients using a flat plate natural
convection correlation Using these coefficients and the material properties and dimensions
of the wall insulation the one-dimensional heat transfer through the cabinet walls is
approximated for the fresh food and freezer compartments Figure 31 shows the
resistances and boundary conditions use in the model
Fig 31 Model Used To Calculate One-dimensional Load
7
The model provides flexibility for varying several parameters This allows application to
various types of refrigerator walls and doors Table 31 lists the input and output
parameters for the model The source code of the simulation along with the output for
completed runs are included in Appendix B
Table 31 One-dimensional Model Parameters
Input Parameters
To K (F) Room ambient temperature
Ti K (F) Interior ambient temperature
LiDs m (ft) WalVdoor insUlation thickness
kiDs Wm-K (Btuhr-ft-F) WalVdoor insulation thermal conductivity
A m2 (ft2) Cabinet surface area
Output
beo Wm2K (Btuhr-ft2_F) Exterior convective heat transfer coefficient
bei Wm2K (Btuhr-ft2-F) Interior convective heat transfer coefficient
hro Wm2K (Btuhr-ft2_F) Exterior effective radiative heat transfer coefficient
hri Wm2-K (Btuhr-ft2_F) Interior effective radiative heat transfer coefficient
qlD W (Btuhr) Heat transfer rate through specified section
32 Determination of Effective Heat Transfer Coefficients
The simulation developed automatically estimates the inside and outside effective heat
transfer coefficients This effective value is the sum of the convective and radiative
components which are defined below
The radiative heat transfer coefficients are computed iteratively using eqs (31) and (32)
assuming (i) gray walls at temperatures T wi or Two with emissivities poundi and Eo (ii) black
surroundings at Ti or To and (iii) walls can see surroundings only
(31)
(32)
8
The convective heat transfer coefficients are estimated from a flat plate natural convection
correlation developed by Clausing (1983) In the laminar regime (Ra lt 1()9) the Nusselt
number based on the film temperature is given by Eq (33)
NUf = 052 Ra4 (33)
For the turbulent regime (Ra ~ 109) the Nusselt number becomes
NUf = 009 Raf3 (34)
where in both cases
Tw+T_ Film temperature T f == 2
Lc == Vertical surface characteristic length g == Gravitational acceleration f3 == Thermal expansion coefficient v == Kinematic viscosity Tw == Vertical wall surface temperature T_ == Outsideinside ambient temperature
kf == Air thermal conductivity
The film temperature characteristic length Nusselt number and Rayleigh number will
have different values for the inside surface compared with the outside surface of the
cabinet Therefore the inside and outside convective heat transfer coefficients are
determined separately from eqs (35) and (36)
(35)
- NUfo kfohco - (36)Leo
9
33 Results
The four primary regions analyzed are (i) the fresh food compartment walls (ii) fresh food
door (iii) freezer walls and (iv) the freezer door The values for the input parameters
ltLins kins A) are taken from a full-size unit that is used for the experimental analysis
presented in Chapter 4 The room temperature is used for the model parameter To Also
the fresh food ambient Tee and the freezer ambient Tfz are substituted for Ti when
suitable in order to closely simulate real operating conditions The results are given in
Table 32
Table 32 Results From One-dimensional Load Analysis
Input
Section TooC eF)
Tj degC eF)
Lins m (ft)
kins Wm-K (Btuhr-ft-OF)
A m2 (fi2)
Fresh Food 21 4 0045 0027 242 Walls (698) (392) (0148) (0015) (2605)
Fresh Food 21 4 0040 0040 089 Door (698) (392) (0131) (0023) (958)
Freezer 21 -10 0056 0027 110 Walls (698) (-140) (0184) (0015) (1184)
Freezer 21 -10 0040 0040 034 Door (698) (-140) (0131) (0023) (366)
Output
Section hco Wm2-K cBtuhr-ft2-Fl
hro Wm2-K iJtuhr -ft2-Fgt
hci Wm2-K (Btuhr-ft2-F)
hri Wm2-K 1Btuhr-ft2-F)
qlD W (Btuhr)
Fresh Food 130 544 198 461 209 Walls (23) (96) (35) (81) (713)
Fresh Food 144 542 218 463 117 Door (25) (95) (38) (82) (399)
Freezer 143 542 226 397 143 Walls (25) (95) (39) (70) (488)
Freezer 164 538 259 400 81 Door (29) (94) (46) (70) (276)
herro =687 Wm2 K (121 Btulhr-ft2-OF) Total qlD =550 W herrrr = 670 Wm2 K (118 Btulhr-ft2_0F) (1876 Btuhr)
herrrz = 641 Wm2 K (113 Btulhr-ft2-OF)
The load for our operating conditions is 550 W (1876 Btuhr) Once again this quantity
does not reflect the total cabinet load on the refrigerator cabinet Edge effects are analyzed
in detail in the following chapters Another important result is the values for the effective
10
inside and outside heat transfer coefficients which are simply the sum of the convective
and radiative components The outside coefficient is heffo the fresh food coefficient is
heffff and the freezer coefficient is hefffz These numbers are used whenever film
coefficients are needed for computations
11
4 EXPERIMENT AL ANALYSIS
This section presents an experimental study performed on a full-size household
refrigerator In Chapter 3 we defined the load due to heat transfer through the walls and
doors of the cabinet as qlD The purpose of this experimental analysis is to quantify qwalh
qdoor qmulloff and Qrnullon and Qmisc Three types of tests are performed to accomplish
this task Descriptions of each are presented separately in the sections that follow
41 Temperature Profile Measurements
The refrigerator is instrumented with many thermocouples in various key areas to give
temperatures across the steel skin and to compare and verify the thermopile tests outlined
in the next section The four primary paths along the steel flange that are examined are the
wall-side fresh food door-side fresh food wall-side freezer and the door-side freezer
Five Type T 36 AWG thermocouples are placed along the skin for each path Figure 41
is a detailed drawing of the location of the thermocouples
Wall side TICs Door side TICs with 5 mm spacing with 5 mm spacing
Fig 41 Steel Skin Temperature Profile Thermocouple Placement
The wire leads are oriented so they run perpendicular to the temperature gradient so as to
reduce any effects of conduction along the wire to the bead The temperature data are fed to
the data acquisition system Each channel is a thermocouple input and is scanned at a rate
of 5 times a second The data are smoothed automatically by the software in blocks of 10
12
points for an average temperature every 2 seconds A full description of the data
acquisition and control system is provided in Appendix D
Data are collected for several runs to provide a good base to detennine average values since
the test conditions vary slightly from run to run To get a good measurement of the
temperature profIles along the steel flange the unit is shut off at the beginning of the run
and allowed to drift to quasi-steady conditions The presence of a large amount of thennal
mass (see Appendix C) within the refrigerator provides for a stable interior ambient
temperature during data collection The outer ambient is controlled by the room thennostat
which keeps the laboratory at a constant temperature to within plusmn1degC
Figure 42 is an example plot of a run that gives the temperature profIles along the steel
skin on the wall-side and door-side for the fresh food compartment
193
192
G 191 ~
i 19
middot5 189F
188
Run I iii --0 - Door Profile
~Imiddotmiddotmiddotmiddotmiddotmiddotmiddott 0 Wall Profue
i ~ i - - T =19273 - 001206x i i-- door i If ~
=-r~r==L~r=I ~ I +~~=~~~~~~~~~ middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot
Outdoor Ambient = 210 degC Fresh Food Ambient =48 degC
187-+----+----J------I----+---~
o 5 10 15 20 25
x (mm) 1 in= 254 mm
Fig 42 Steel Skin Temperature Plot for Fresh Food Compartment
The dashed line represents a linear least-squares fit for the door data and the solid line is the
corresponding fit for the cabinet wall data Each data point in the plot represents the
average temperature at that point over a period of time at quasi-steady conditions
Similarly Figure 43 is a plot of the temperature profIles for the freezer
13
186
184
a 182
~
i 18
5 178~
176
174
Run 1 t-- 1 1 --0 - Door Profde
P~P1 0 Wall Profile
- -LLl--=-+--shy- - Tdo = 18606 - O02354x i
or ~
=c==-rc1 1 ltb 1 ~
~~r--r- -r---shy0 5 10 15 20 25
x (mm) 1 in= 2S4mm
Fig 43 Steel Skin Temperature Plot for Freezer
A total of six separate runs were perfonned three for the fresh food compartment and three
for the freezer Plots for the other runs are located in Appendix E
From the figures above for the fresh food compartment the slope on the wall-side is
slightly steeper than the slope on the door-side In fact this trend is seen for all the runs
Therefore the heat conduction along the metal skin into the cabinet along the wall is
somewhat greater than that of the door For the freezer the slopes are nearly equal hence
the heat conduction along the wall skin and the door skin are nearly the same
42 Thermopile Testing
Another simple but important test is the use of a thennopile to measure the average
temperature difference at various locations on the steel flange regions of the unit Figure
44 is a schematic of the thennopile test set-up The thennopile is constructed from 36
AWG copperconstantan thennocouple wire
14
-
CopperConstan$t Junctions 285 mPt
IOmm
10mmThermopile
IOmm
Digital Multimeter
1 in= 254mm
Fig 44 Thermopile Test Apparatus
Five junctions are used for the fresh food compartment and three for the freezer The
junctions are mounted 10 mm (039 in) apart from one another along the steel skin beneath
the door seal Figure 45 is a detailed drawing of the lateral location of the thermopile
junctions
15
1 in =254 mm
Fig 45 Thermopile Placement
The thennopile provides an average temperature difference across the junctions The
output voltage must frrst be divided by the number of pairs of junctions and then translated
into a temperature difference using a referencing chart for the thennocouple wire Table
41 is a summary of the results from these tests The output voltages are read accurately to
within plusmn0002 mV The raw data and data reduction procedure are given in Appendix E
Table 41 Thermopile Output
Test Conditions Fresh Food aT Freezer aT TodegC
(OF) TffoC
(OF) Tfzoc
(OF) aTwallff degC
(Of) aTdoorffoc
(OFgt aTwallfzoC
(Of) aTdoorfzoC
(OFgt
1 210 (698)
48 (406)
-88 (162)
026 (047)
024 (043)
037 (067)
041 (074)
2 210 (698)
37 (387)
-87 (163)
027 (049)
026 (047)
038 (068)
040 (072)
3 208 (694)
37 (387)
-93 (153)
027 (049)
026 (047)
038 (068)
040 ( 072)
Average Values 209 (696)
40 (392)
-90 (158)
0267 (0481)
0253 (0455)
0377 (0679)
0403 (0725)
43 Thermocouple Drag Testing
One final technique applied is thennocouple drag testing This is a more qualitative method
to supply insight into what exactly is happening when the compressor is pumping wann
16
refrigerant through the anti-sweat tube that lines the perimeter of the cabinet aperture The
main objective of this test is not to give accurate temperature proftle infonnation but
instead to detennine the placement of the condenser tube This is needed as an input for
the numerical simulation of this region The reason that the temperature are not accurate is
the fact that the thermocouple is being dragged across a surface where good thermal contact
may not occur and significant energy may be generated Figure 46 is a schematic of the
apparatus used for drag testing
Power Supply
Data Acquisition System
Outer Metal Skin
Potentiometer
Inner Plastic Skin
Condenser Tube
Fig 46 Thermocouple Drag Test Apparatus
This device is quite simple yet very effective The type T 36 AWG thennocouple begins
at the interior boundary of the steel skin beneath the seal on the wall-side of the cabinet
The potentiometer is turned by hand moving the thennocouple oqtward along the skin
The temperature and location are stored simultaneously this way The thennocouple is kept
17
pressed against the steel flange by the seal The linear translation of the thennocouple is a
function of the output voltage Voutbull
s = 2mllT Vout (41)Yin
r =radius of potentiometer post =30 mm (012 in)
nT = total number of turns of potentiometer = 10
Vin = input voltage = 05 V
Vout = output voltage
Drag tests are run on the wall steel skin for both the fresh food compartment and the
freezer Runs are perfonned at four separate times the first being when the compressor
turns on Figure 47 is a plot of the drag proflles across the wall-side skin in the fresh food
compartment Figure 48 is a plot of the profiles in the freezer compartment The same
trends are generally seen for both regions The freezer profiles are simply shifted down in
temperature values as expected The temperature peak seems to move through time to
settle near the center of the flange region under the seal
31
30
29
G
i 28~
27
26~
25
24
23
e
Ji ~ i i i 1middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotlmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddoti~~
---l- Time 4
o Time 2 rr
i
0 5 10 15 20 x (mm)
Fig 47 Drag Profiles (Fresh Food)
18
26~--------+---------~-------4--------~
i ~
Time 1 24
22
20
18
16~~------+---------~-------4--------~
4 __
~~Time3
middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot_middotmiddot_middotmiddotimiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot
Outer Seal Edge o
o 5 10 15 20
x (mm)
Fig 48 Drag Profiles (Freezer)
44 Experimental Determination of qwall and qdoor
The results from the temperature profile and thennopile testing are used to detennine qwall
and qdoor according to the following defmitions
qwall = qwallff + qwallfz (42)
(43)
Where qwal1ff = heat conduction along wall-side fresh food compartment steel flange
qwallfz = heat conduction along wall-side freezer compartment steel flange
qdoorff = heat conduction along door-side fresh food compartment steel flange
qdoorfz = heat conduction along door-side freezer compartment steel flange
The trends derived from the fixed profiles exhibit generally good agreement with the
temperature differences seen by the thennopile For the fresh food compartment the
thennopile displays a slightly larger AT than what is seen in the profiles and both give a
19
slightly larger temperature difference for the wall-side compared with the door-side For
the freezer the temperature differences match closely on the wall-side however the doorshy
side AT is shown to be somewhat less than the wall-side AT for the fIXed thennocouple
measurements where the opposite is seen from the thennopile The worst discrepancy is
on the order of 10 and is probably due to the fact that the thennopile gives an average temperature difference at several vertical locations on the wall whereas the other method is
at one vertical location only
Since the thennopile produces an average temperature difference across the steel skin its
output is used to detennine the heat flux into the cabinet The refrigerator casing is being
used as a heat meter Thus the flux along the skin in the fresh food compartment on the
wall-side is
kmiddot ATwallffqwallff = m (44)
Ax
The load qwallJf is Eq (44) multiplied by the cross sectional area This area is the
thickness of the steel casing multiplied by the perimeter that is exposed to the room
ambient This perimeter varies for each of the two paths that comprise qwall and the two
paths that comprise qdoor The other cabinet loads are computed in a similar way and are
given in Table 42 The details of these values are given in Appendix E
Table 42 Experimental Determination of qwall and qdoor
Section Load W (BtuIhr)
qwallJf 28 (96)
qwallJz 21 (72)
qwall 49 (168)
qdoorff 33 (112)
qdoorJz 33
1112)
qdoor 66 (224)
20
45 Experimental Determination of qmulloff
The region that lies between the fresh food compartment and the freezer is called the
mullion The front portion of the mullion is covered by a thin steel face plate to provide a
suitable interface for the door seal magnets In this section the load due to heat conduction
along the mullion steel skin into the freezer and fresh food compartment is detennined
based on the experimental data
The heat transfer rate qmulloff is sum of two parts The first component is the heat
conduction along the steel plate into the fresh food compartment and the second is the
conduction into the freezer
qmulloff = qmulloffff + qmullofffz (45)
Figure 49 schematically illustrates paths of these two components
FREEZER
FRESH FOOD COMPARTMENT
Fig 49 Heat Flow Paths in Mullion
21
Ten 36 A WG type T thennocouples are mounted from top to bottom across the steel face
plate Figure 410 shows the cross section of the plate and the location and numbering of
the thennocouples
FREEZER
1bennocouplesSteel Face (5 mm spacing from
Plate bottom edge)
Freezer Gasket
Fresh Food Gasket
10 50
FRESH FOOD COMPARTMENT
1 in =254 mm
Fig 410 Mullion Face Plate Cross Section
Data are gathered from the ten thennocouples when the unit is shut off and allowed to drift
to a quasi-steady ambient temperature A total of five runs were perfonned Figure 411 is
a sample plot of the quasi-steady temperature profile All other plots are contained in
AppendixE
22
116
Run 1 I 115 ICcIIIII114 iii t ~mull~ =12~7 - 00~654xa
~ 113
rrfIIJ~~If112i 5 )mullfz 1= 1081~ + OOdl25X 111111 ~
11 oo+-t--t-iH-+-lo-shyiii i i Room Ambient = 2184 degc
109 middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1middot Fresh Ambient = 381 OC
108
1 10
I I I I I Freezer Ambient =-832 degc
2 3 4 5 6 7 8 9
TIC
Fig 411 Mullion Temperature Profile
The plot also shows two linear equations These represent linear fits to each side of the
peak temperature at TIC 7 The slopes (shown in degCmm) are used to detennine the heat
conduction to each compartment by eqs (46) and (47)
lmulloffff = km A (aT) (46)ax offff
qmul)offfz = km AIll) (47)ax offfz
The cross sectional area is the product of the face plate thickness (10 mm 0039 in) and
the length of the mullion (717 mm 2825 in) The average slopes from all five runs are
used to detennine qmulloffff and qroullofffz The results are given in Table 43
23
Table 43 Experimental Results from Mullion Analysis
Load W (Btuhr)
09qmullofUz (31)
07qmulloffff (24)
16qmuIlorr (55)
46 Experimental Determination of qmullon
In this section the load due to heat conduction along the mullion steel skin into the freezer
and fresh food compartment when an anti-sweat heater is on is experimentally determined
The test unit is equipped with an electric anti-sweat heater to eliminate condensation in the
mullion region The heater is installed on the back side of the plate and may be switched on
manually when needed It is a wire resistor type rated at 10 watts
The heat transfer rate qmullon is composed of two parts The first component is the heat
conduction along the steel plate into the fresh food compartment and the second is the
conduction into the freezer similar to ~ul1off
qmuIlon = ~ullonff + qmuIlonfz (48)
The location of the wire heater and the heat transfer paths are shown in Figure 412
24
FREEZER
qmullonfz
qmullonff
FRESH FOOD COMPARTMENT
Fig 412 Electric Heater Location
A series of tests are perfonned while the heater is on and the refrigerator is cycling
nonnally Three runs are done at each of three separate locations along the mullion
laterally (i) LEFT dermed as 180 mm (71 in) from the left-hand side of the unit (ii)
RIGHT 180 mm (71 in) from the right-hand side of the unit (iii) CENTER at center of
the mullion Figure 413 is a plot of the temperature profile across the face plate when the
heater is on for a specific test run The plots for all other runs are provided in Appendix E
The plot shows two profiles These represent the upper and lower limits as the unit cycles
The upper limit occurs just before the compressor turns on while the lower limit is at the
point in time just before the compressor shuts off At all times in between the profile
oscillates between the two limits maintaining nearly the same shape Once again a linear
fit is applied to the data on the fresh food side and the freezer side
25
30 iii imiddot iii i
29
28
27
Run 1
T mu
ill~~ 11 f = 26707 + 010776x Tmu11ff = 3128 - 00793x
Z +_ a 26~
I ~
middotmiddotmiddotbull-middotbullimiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotimiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotimiddotmiddotmiddotimiddotmiddot
24
25
e 23~ =H-T+H~i=i=
iimiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotimiddotmiddot T 11 ff = 27435 - 009504x 22 Tmullfz =21865 + 01l786x I m~ iii
21 -lmiddotmiddotmiddotmiddotmiddotmiddotmiddot-tmiddot Upper Limlt 0
20 middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotjmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotimiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddott 0 Lower Limit
19
0 1 2 3 4 5 6 7 8 9 10
TIC I
Fig 413 Mullion Temperature Profile With Heater On (Center)
Heat fluxes are computed identically to the method in Section 45 using the average slopes
from all nine runs The minimum value occurs just before to compressor turns on while
the maximum value occurs just before the compressor shuts off during normal cycling
The load is averaged over the cycle time which is approximately 50 for the test unit and
laboratory conditions The results are given in Table 44
Table 44 Experimental Results from Heater Analysis
Lower Profile Average W
(BtuIhr)
Upper Profile Average W
ffituhr)
qmullonfz 73
(249) 53
(181)
qmullonff 23 (78)
26 (89)
96 (32 7)
79 (270)
qmullon 88
300)
26
47 Determination of Qmisc
The load qoisc is comprised of three main parts The first is the load due to the evaporator
fan motor The fan that moves cool air in the cabinet also adds a thennalload Fans of this
type in use range from 8 - 16 watts The fan of our test unit is rated at 92 watts This
value must be integrated over the cycle time The cycle time for the unit is approximately
50 for the test conditions Thus the value of qfanave is 46 watts
The load qdefrostave is not determined experimentally Instead an estimate is obtained from
a similar study done by Turiel and Heydari (1988) This value is 5 watts which is an
average of the defrost heater input over the defrost cycle The defrost cycle can range from
10 - 12 hours of compressor run-time
The fmalload qcompave is detennined by measuring the cabinet surface temperature at the
region surrounding the compressor and computing the heat transfer locally The value is
found to be 2 watts Table 45 summarizes the results
Table 45 Miscellaneous Loads
Load W CBtuhr)
46 qfanave (15middotU
50 qdefrostave _07Ql
20 qcompave (68)
116 Qmisc (395)
27
s NUMERICAL SIMULATION
In this chapter a two-dimensional numerical model which is used to simulate the steadyshy
state heat transfer in the wall near the door seal is discussed The results from the model
include a computation of qwallff qwallfz and the complete temperature distribution across
the section The model is also used to estimate the additional cabinet load due to the
presence of an anti-sweat condenser tube embedded beneath the outer casing that runs
along the perimeter of the unit A separate model is presented which is used to simulate the
two-dimensional heat transfer across the door seal cross section The results are used to
determine qseal
51 Wall Model
A finite-difference technique is used to approximate the steady-state temperature
distribution in the wall section The technique is applied to solve the governing steady
two-dimensional heat conduction equation (assuming constant conductivity with no
generation)
(51)
Equation (52) is the basic fmite-difference representation of the conduction equation in a
homogeneous medium of constant conductivity with no heat generation (White 1988) In
Appendix F a complete list of all the model difference equations is provided
2(1+(3)Tij = (3Tij+l + Ti+lj+(3Tij-l + (3Ti-lj (52)
where (3 = (llxlly)2
28
Figure 51 is a sketch of the model representation of the refrigerator wall at the door seal region The dimensions shown are flexible parameters in the model The model allows for
slight changes in the geometry as well as changes in mesh size in both x and y directions
However the mesh size must remain uniform across the section
s5 s6
sl
Fig 51 Wall Heat Conduction Model Sketch
For each of N unknown nodal temperatures N simultaneous linear algebraic equations are obtained for N unknowns If N is large as is the case for this simulation an iterative
technique is preferred to solve the system ofequations A Fortran program has been
written to carry out the finite-difference iteration A copy of the code is given in Appendix
F A simple Guass-Seidel technique is employed for the differencing iteration At each
iteration an energy balance is done for the entire section In theory this balance should be
29
zero (heat entering) = (heat leaving) The iteration is continued until the difference
between heat entering and heat leaving is equal to 1 of the total heat entering the section
Table 51 defines the input parameters for the simulation
Table 51 Wall Simulation Input
Code Parameter Definition
To C (F) Exterior surrounding ambient temperature
Ti C (F) Interior ambient temperature
lan Wm-K (Btuhr-ft-F) Steel skin conductivity
kp Wm-K (Btuhr-ft-F) Plastic skin conductivity
kins Wm-K (Btuhr-ft-F) Wall insulation conductivity
heffo Wm2-K (Btuhr-ft2-F) Outside effective heat transfer coefficient
hefti Wm2-K (Btuhr-ft2-F) Inside effective heat transfer coefficient
dm mm (in) Steel skin thickness
dp mm (in) Plastic skin thickness
dx mm (in) Mesh size x direction
dy mm (in) Meshsizeydirection
sl mm (in) Wall width
s2 mm (in) Wall length
b mm (in) Effective Perimeter
s3 mm (in) Seal indentation
s4 mm (in) Seal width
s5 mm (in) Depth of steel skin into cabinet along seal boundary
s6 mm (in) Width of plastic skin along seal boundary
The model assumes that the boundary that lies along the door seal is adiabatic This allows
the separation of the wall section from the rest of the geometry in this region The seal and
door can then be treated separately later A simple calculation is done to validate this
assumption
30
Steel Skin (Refrigerator wall)
Seal (k = 02 Wm-K)
Fig 52 Non-adiabatic Door Seal
A 2 degC temperature difference AT is imposed across the seal This is a slight overshy
estimate based on the experimental data An estimate of the conductive heat flux is
determined from Eq (53)
ATqerror=k- (53) Ax
qrror =02 Wm-C o~Cm =20 Wm2
The heat flux ql for the fresh food compartment is determined in Appendix E to be 14418
Wm2 Therefore qerror represents approximately 13 of the total flux Hence this
term is neglected in this study
Two other possible sources of error are associated with the fmite-difference technique itself
(Ozisik 1980) The fIrSt is called truncation error and arises from the discretization of the
second-order derivative in the steady conduction equation The second is referred to as the
round-offerror which is due to the fact that numerical calculations are carried out only to a
finite number of decimal places Repeated solution with smaller increments shows that the
truncation error is negligible The precision of the energy balance is evidence that the
round-off errors are negligible
31
S2 Wall Simulation to Determine qwall
The finite-difference model is used to detennine the wall-side heat transfer along the steel
skin However more valuable information is yielded from the simulation The nodal
temperature distribution is detennined which gives insight into the direction and magnitude
of heat fluxes throughout the section The fresh food compartment and the freezer are both
simulated to detennine qwallff and qwallJz respectively Table 52 is the list of the values
used for the model input parameters for both cases
Table S2
Code Parameter
To C eF)
Ti C eF)
kIn Wm-K (Btuhr-ft-F)
kp Wm-K (Btuhr-ft-F)
kins Wm-K (Btulhr-ft-F)
heffo Wm2-K (Btuhr-ft2_F)
heffi Wm2-K (Btuhr-ft2-F)
dm mm (in)
dp mm (in)
dx mm (in)
dy mm (in)
sl mm (in)
s2 mm (in)
b mm (in)
s3 mm (in)
s4 mm (in)
s5 mm (in)
s6 mm (in)
Input Values
Fresh Food 210 (698) 40
(392) 540 (312) 015 (009) 0027 0015t 687 (121) 670 (118) 065
(0026) 25
(0098) 225
(0088) 25
(0098) 450
(1772) 2000 (7874) 2960
(11653) 225
(0088) 2025 (0797) 225
(0886) 2025 (0797)
32
Freezer 210 (698) -10
(140) 540middot (312) 015 (009) 0027 (0015) 687 (121) 641 (113) 065
(0026) 25
(0098) 28
(0088) 25
Jo098) 540
(2125) 2000 (7874) 1580
(6220) 28
(0110) 196
JO772) 224
(088t) 288
(1134)
The output from the simulation includes the entire nodal temperature field heat fluxes at
each node along the centerline heat fluxes from node to node along the steel skin beneath
the door seal and the value for qwallff and qwallcz These heat transfer values and the
nodal temperature distribution are listed in Appendix F
The quantities qwallff and qwallcz are determined by computing the heat fluxes from node to node along the centerline of the section subtracting the one-dimensional flux and then
multiplying by the cross sectional area for that node and summing to give the total heat
transfer rate The primary results are shown in Table 53
Table 53 Wall Simulation Results
Section
The temperature distributions are shown in the following two figures Figure 53 shows
the temperature contour for the fresh food results Figure 54 is the same plot for the
freezer results
Since the geometry of the refrigerator door is similar to that of the wall along the edges the
heat leakage to the food compartments along the door flange can be approximated as being
roughly the same as qwall This approximation of qdoor is a good means of estimating the
two prime contributors to the edge loss for various different refrigerators which may have
slightly different geometries as well as different material properties
33
i
3875
3625
TemplaquogtC)
-e
11111
20
18
16 3375
g 3125 14 -5 2875 ~ 122625 ~
2375~ 102125~
1875 8
1625
1375 6
1125
875 4
625
375
SteeVPlastic Liner Interface
Fig 53 Fresh Food Wall Temperature Distribution
34
i 4875
4625
4375
4125
3875
3625
3375 -
3125e g 2875
2625 ~ 2375 ~ 2125c (I)
1875 ~ 1625
1375
1125
875
625
375
125
Fig 54 Freezer Wall Temperature Distribution
Temp(OC)
20
15
10
5
0
-5
-10
35
53 Wall Edge Simulation to Determine qtube
The wall simulation is modified to include a constant temperature node placed beneath the
steel flange to represent the presence of an anti-sweat condenser tube The simulation is
perfonned for the specific conditions that are typical of the test unit as well as a range of
lateral tube locations For the test refrigerator the tube is located as shown in Figure 55
and is at 35degC (95 OJlt)
Outer Steel Skin
14625 mm 1
Inner Plastic Liner
Fig 55 Tube Location for Simulation
The quantity qtube is detennined by taking the fluxes along the vertical line to the left of
the tube subtracting the one-dimensional flux and then multiplying by the cross sectional
area for that node and summing to give the total heat transfer rate Again the fresh food
compartment and the freezer must be simulated separately to produce a total governed by
Eq (54)
(54)
Program output for the fresh food and freezer simulations is given in Appendix F Table
54 summarizes the results from the model
Table 54 Wall With Condenser Tube Simulation Results
Section Load W iBtubrl
qtubeff 46
(157)
qtubefz 28 (96)
qtube 74 (253)
qtube8ve (ave for 50 cycle time)
37 (126)
36
-I i c IJ
~
r 4875
4625
4375
4125
3875
3625
3375
3125
2875
2625
2375
2125
1875
1625
1375
1125
875
625
375
125
TempfC)
SteeVPlastic Liner Interface
35
30
25
20
15
10
5
Fig 56 Fresh Food Wall Temperature Distribution Including Warm Anti-sweat Tube
37
TempfC)4875
4625
4375
4125
3875
3625
3375 - 31258
2875g 2625fo 2375
3 2125 d vI 1875
~ 1625
1375
1125
875
625
375
125
SteeVPlastic Liner Interface
Fig 57 Freezer Wall Temperature Distribution Including Warm Anti-sweat Tube
38
40
30
20
10
0
-10
The heat fluxes at each node along the vertical line to the left of the tube are also computed
by the simulation This value quantifies the amount of heat that is moving toward the outer
boundary and is used to determine the percentage of heat entering the cabinet For the test
refrigerator this value is 18 for the fresh food compartment and 24 for the freezer
Several more simulation runs were done to find the effect of lateral placement of the tube on
the overall heat transfer and the percentage of heat entering Figure 58 and Figure 59
show the trends that are found
-~ a tUbe ~middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotlmiddotmiddotmiddot=middotmiddot=pmiddotmiddotmiddot=middot-1- =1
middot middot middoti middot middotmiddotmiddotmiddotmiddotmiddotmiddotmiddot bull middotmiddotmiddot i middotmiddotmiddotmiddot middotmiddot middotmiddot ~ middotmiddot
middotmiddotrmiddot-rmiddot 0 lwbeff middotlmiddotmiddot~middot Gmiddottmiddotmiddot9middotlmiddot
i i -0- lwbe i middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotimiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddot fz tmiddotEimiddotmiddot ~G- -~ -q- -
0 5 10 15 20 25 x(mm)
Fig 58 Load Due to Condenser Tube for Various Tube Placements
8
~ - 7
50
a 6
~ 5
~ en 4 ~
pound ~ 3
2
- 26
~ a 24
middots bO
pound 22c ~
~ 20
a = 18sect ~
16 0 5 10 15 20 25
x (mm)
Fig 59 Percentage of Heat Entering Cabinet for Various Tube Placements
39
54 Door Seal Simulation to Determine qseal
Another model is developed for the two-dimensional heat transfer through the door seal
This model is very similar to the one created for the wall section Once again a fIniteshy
difference technique is utilized to detennine the temperature distribution at steady-state
conditions Even though the cross sectional geometry of the seal is simplifIed to a square
with a hollow square with a centrally located cavity no closed-form solution can be
applied Therefore a simulation is needed
The fInite-difference representation of the two-dimensional steady Eq (55) using central
differencing is given by Ozisik (1980)
Ti-lj - 2Tij + Ti+lj + Tij-l - 2Tij + Tij+l = 0 (55) Ax2 Ay2
For this model a square mesh is applied reducing Eq (55) to
Ti-lj + Ti+lj + Tij-l + Tij+l - 4Tij = 0 (56)
x
Fig S10 Seal Simulation Mesh Layout
40
The nodes along the vertical surfaces at x=O and x=20 are subject to the convective
boundary conditions and governed by Eq (57) and Eq (58) respectively
2~xheffol 2~heffo2Ti+lj + Tij-l + Tij+l - (4 + k TiJ = - k To (57)
seal seal
2~heffffl 2~heffff2Ti-lj + Tij-l + TiJ+l - (4 + kseal Tij = - kseal Tff (58)
The nodes along the top and bottom outside surfaces are held at the prescribed temperature
profIles which are detennined from experimental data (see Section 41) The interior nodes
are subject to radiant e~change among themselves and conduction through what is assumed
to be stagnant air A closer look at the model of the hollow interior of the seal is shown in
Figure 511
Fig 511 Seal Cavity Mesh Details
Each interior node corresponds to a single gray surface with assumed emissivity of 09
Viewfactors for all surfaces are computed automatically before the iteration begins For
each iteration the effect of radiation within the enclosure is taken into account by updating
surface radiosities Jij Thus for nodes on interior surfaces an extra tenn is added to the
governing difference equation (Eb is the blackbody radiation)
41
~(J - Eb )1-pound IJ lj
A code written in Fortran is used to perfonn Guass-Seidel iteration of the difference
equations to compute the temperature distribution at mesh nodes (Code listing in Appendix
F) Once again convergence is based on an energy balance applied to the entire section
The iteration is continued until the difference between heat entering and heat leaving is
equal to 01 of the total heat entering the section Table 55 lists the input parameters
used in the model The fresh food compartment and the freezer compartment are simulated
separately
Table 55 Seal Simulation Input
Code Parameter Fresh Food Freezer
Number of nodes along outside edge 20 20
Number of nodes along inside edge 6 6 1 1Lx = fly mm (in) (0039) (0039)
210 210Outdoor ambient temperature degC (oF) (698) (698) 150 105Indoor local ambient temperature degC COF) 590J j509)
Outdoor heat transfer coefficient W m2-K 687 687 (121) (121)(Btuhr-ft2-F)
Indoor heat transfer coefficient Wm2-K 670 641 (118) (113)(Btuhr-ft2-F)
Gasket interior surface emissivity 09 09 03 03Gasket conductivity Wm-K (Btuhr-ft-F) (0173) (0173)
Wall-side Temperature Boundary 1905 - 1977x 1813 - 3475x Condition degC Door-side Temperature Boundary 1913 - 1384x 1852 - 2341x Condition degC
42
The load results are summarized in Table 56 below The program output is listed in
AppendixF
Table 56 Seal Simulation Results
Load W Section (BtuIhr)
10 Qsealff (34)
ljQsealfz (Sn
25qseal (85)
The steady-state temperature distribution is shown in the figures below Figure 512 is the
fresh food simulation and Figure 512 is the freezer simulation The direction of the heat
flow through the section is easily seen from these plots
43
Wall-side Boundary Temperature (C)
~~
I 20
195
i 19t 0
8 ~ 1859 -- ~
isis ~ ampJ gtshy 18 ~
11 ~ S ~ 175~
~ 17
165
x(mm)
Door-side Boundary
Fig 512 Seal Temperature Distribution (Fresh Food)
44
Wall-side Boundary Temperature (C)
Ii 19
185
18i f IQ 5 IQ
175-is-is I s 17j ~
5e 0C= 165
~ ~ 16
155
x(mm)
Door-side Boundary
Fig 513 Seal Temperature Distribution (Freezer)
45
6 DISCUSSION OF RESULTS
The heat transfer values detennined from the experimental analysis and the numerical
simulations are the various components that embody the cabinet load on the refrigerator It
is important to separate cabinet loads from system loads The system load can be thought
of as the total electrical energy consumption of the unit It has four basic components (i)
the compressor (ii) fans (iii) anti-sweat heaters and (iv) defrost heaters The first two
components the compressor and fans are the cost of removing heat from the cabinet This
amount of heat is equal to the cabinet load divided by the COP of the system The typical
energy consumption is shown schematically in Figure 61
System Load (Energy Consumption)
Defrost Heater (averaged over time
cycles every 10-12 hours of compressorrurt-time)
TuneCycle
Fig 61 Refrigerator System Load Graph
In a study done by Turiel and Heydari (1988) the compressor and fans accounted for 84
of the total system load for an 180 cubic foot top-mounted refrigerator Staley (1992)
found this value to be 86 for a similar unit Both of these studies used system analysis to
determine these numbers The energy consumption of the components were monitored
during operation The energy consumption of our test refrigerator can be determined in a
reverse manner from the cabinet load data If a COP of 1 is assumed the test refrigerator
46
compressor and fans accounts for 86 of the energy consumption to cool the cabinet This
compares favorably with the fmdings of Turiel and Heydari (1988) and Staley (1992)
Figure 62 is a schematic of the cabinet loads One possible load that is not included in the
figure is the heat input associated with the defrost drain tube that runs through the back
wall However this term is probably small relative to the other contributors
Cabinet Load
qseal qdoor
qwall
qmullon
qdefrostave
Fig 62 Cabinet Loads Graph
All the loads are determined in this study from either experimental measurements
numerical simulations or both Most of the loads are quasi-steady that is they do not
fluctuate significantly over the cycle time of the refrigerator There are four loads shown in
Figure 61 that are cyclical in nature The three loads that appear only while the
compressor is running are qcomp qfarb and qtube Also the refrigerator is subjected to a
load every time ice build-up is removed by the defrost heaters This load is averaged over
its own cycle time and shown in the graph as qdefrostave
47
61 Comparison of Simulation Results with Experimental nata
The majority of the cabinet loads are detennined from experimental data with the exception
of qseal and qtube The wall and door flange loads aremiddot also found from the numerical
simulation (see Chapter 5) The two-dimensional model detennines the wall-side heat
transfer along the steel skin into the food compartments No model is available to directly
detennine the heat transfer on the door-side However since the flange geometry on the
door-side is similar to the wall the value for qwall is considered to be a good estimate for
qdoor Table 61 gives these values determined from experimental measurements and the
simulation
Table 61 Comparison of Simulation and Experimental Values for qwall and qdoor
Experimental Result W Simulation Result W (BtuIhr) (BtuIhr)
qwallff 28 (96)
28 (96)
qwallz 21 (72)
27 (92)
qwall 49 (168)
55 (188)
ldoorff 33
(112) 28 (96)
qdoorfz 33
(112) 27 (92)
qdoor 66 (224)
55 (188)
The model predicts qwall to within 57 of the experimental value The agreement of the
estimate of qdoor with the experimental value is within 90
Some of the shortcomings in the model used in this investigation are
(i) Only the wall is modeled Ideally the entire region should be considered including the
door and seal (see Figure 11)
(ii) The flange geometry is simplified The steel casing skin in the flange region may bend
in more complex ways Also the plastic liner varies in thickness near the door seal
(iii) The mesh must be unifonn There is no means to vary how fme the mesh can be The
ideal situation would be to have a fine mesh near the edges and a course mesh far from the
seal
48
62 Mullion Analysis
The single largest edg~ load is found in the mullion section (329 of qedge and 94 of
qtol) This load is due to the electric anti-sweat heater installed on the backside of the face
plate The heater is rated at 10 watts and approximately 88 of that input enters the
interior of the cabinet as a thennalload This is probably due to the small surface area
exposed to the room and the low amount of convective heat transfer in the channel between
the fresh food and freezer doors With the heater on 88 watts is measured enter the food
chambers With the heater off only 16 watts enters the interior The addition of the
heater increases the mullion load 55 times Generally it is not necessary to use the
mullion heater at all times However for the test environment the heater nearly all the time
to eliminate sweating under the laboratory conditions
63 Seal Analysis
The heat conduction directly through the seal accounts for the smallest portion of the edge
loss (94 ofqedge and 27 of qtol) The numerical model to detennine these values uses
a simplified representation of the complex cross sectional geometry of an actual door seal
The various air pockets are reduced to a single hollow void There is no experimental data
to verify the model However the numbers and trends resulting from the simulation are
reasonable
64 Anti-sweat Condenser Tube Analysis
Thennocouple drag tests were perfonned to give insight into the nature of the temperature
profIles at the wall steel flange with the presence of an anti-sweat condenser tube The wall
heat transfer simulation model was modified to include the effect of this tube The heat
conduction to the interior increased by 76 at the wall flange region The amount of
additional loading due to the tube depends on several parameters location of the tube
temperature of the circulating refrigerant and local wall geometry Although the model is
flexible enough to handle vari01~S temperatures and limited geometrical changes only the
influence of tube position was investigated As the tube is moved towards the interior the
load increases For the test refrigerator about 20 of the heat flow was directed to the
interior compartments primarily along the steel skin
49
6S Overall Cabinet Load
The overall cabinet load is defined as a sum of three parts
(61)
The edge load is
qedge = qwall + qdoor + Qseal + Qrnullon + qtubeave (62)
where
qwall
qtubeave
heat input due to the conduction along the wall steel flange
heat input due to the conduction along the door steel flange
heat conduction directly through the door seal
heat input due to conduction in the mullion region with the additional input from anti-sweat heater
heat input due to cabinet anti-sweat condenser tube averaged over the cycle time
heat input due to cabinet anti-sweat condenser tube
qmulloff heat input due to conduction in the mullion region electric heater off
The terms of Qrnisc are defined as
qmisc = qfanave + qdefrostave + qcompave (63)
where
qfanave heat input from the evaporator fan averaged over the cycle time
qdefrostave heat input from the defrost heaters averaged over defrost cycle time
qcompave heat input from elevated exterior walls near the running compressor
Table 62 presents the overall cabinet load analysis results
50
Table 62 Overall Cabinet Loads
Load W Load Btuhr Total
qlD 550 1876 591
qedge 265 903 285
Qwall 49155 167 188 53
Qdoor 66155 2251 188 71
Qseal 25 85 27
Qmullon 88 300 94
Qtubl ngt 37 126 40
qmisc 116 395 124
Qfanave 46 157 49
Qdefrost ave 50 170 54
qcomoave 20 68 21
qtot 931 3174 100
Simulation Results
All loads are detennined experimentally with the exception oflsea1 and qtubeave The
values for qwall and qdoor are detennined from both experimental data and numerical
simulations Edge loss per unit length along fresh food perimeter is 29 Wm (30 Btuhrshy
ft) the loss per unit length along the freezer perimeter is 44 Wm (46 Btuhr-ft) and the
loss along the mullion section is 123 Wm (128 Btuhr-ft) with the heater on and 22 Wm
(23 Btuhr-ft) with anti-sweat heater off
The largest single load is the one-dimensional conduction through the walls and doors
The edge load comprises 285 of the total a significant portion The largest edge load is
due to the electric anti-sweat heater that is installed in the mullion section The smallest
edge load is due to the heat conduction through the fresh food and freezer door seals The
losses at the wall-side and door-side flange regions account for 53 and 71 of the total
load respectively These could be considered together since the pathway of heat transfer is
very similar If that were the case the sum of qwall and qdoor would be the second largest
contributor to the overall cabinet load The influence of an anti-sweat condenser tube is
reflected in the value of qtubeave Although this additional load is larger than qwall it must
be integrated over the refrigeration cycle timewhich is 50 of the cycle time for the test
unit The tube boosts the heat transfer along the wall flange by 76
51
To round out the cabinet load three miscellaneous loads are considered The evaporator
fan motor produces a heat load within the cabinet which is considered to be equal to the
power rating of the fan The automatic defrost feature is another thermal load that is
cyclical appearing about every ten to twelve hours of compressor runtime The fmalload
is due to the elevated exterior skin temperature near the compressor when it is running All
three of these loads are averaged over their cycle times for comparison with other quasishy
steady loads As a total qmisc represents 124 of the overall cabinet load
Opportunities to decrease the one-dimensionalload are available The emphasis has been to
develop super-insulations to be installed in the refrigerators Some being considered are
vacuum panels aerogels and vacuum packed powder insulations The disadvantages of
this improvement lies within the need to develop a cost-effective technique for fabricating
and installing such technologies compatible with high-volume manufacturing Also edge
losses and panel connection losses must be minimized due to the difficulty in making a
panel the size of refrigerator interiors Reliability of the seal and perfonnance of the outer
envelope need to be ensured over a long period of time ie the expected life of the
product
The possibilities of reducing the loads along the edge of the refrigerator aperture are
somewhat less apparent One method of reducing quasi-steady heat conduction along wall
and door flanges is to raise the inside cabinet wall temperature by minimizing interior film
surface heat transfer coefficients This could be accomplished by the use of low-emissivity
surfaces on the interior walls or on sections nearest the edges The need for an anti-sweat
device for the perimeter is also eliminated supplying a two-fold savings by reducing the
cabinet ioad and the system energy consumption The need for an electric mullion heater
might also be done away with by the same means The drawback again would be to make
such modifications acceptable and cost-effective for manufacture
The remaining miscellaneous loads provide some chance for improvement If the
efficiency of the fans is increased the energy use of the refrigerator can be reduced The
option of moving the fan motor outside the cabinet leads to other problems The motor
shaft must pierce the wall providing another path for heat leakage Also frost built-up on
the shaft would be a costly and difficult problem to eliminate If the compressor and
condenser were located near the top of the refrigerator they can operate more efficiently
Heat can be more readily convected away eliminating the need for the condenser fan
(Turiel and Heydari 1988) Frost fonnation in the freezer varies significantly depending
52
on the ambient conditions and the freezer usage The defrost cycle could be made more
energy efficient with the addition of adaptive controls All of these improvements would
require redesign of the product and the manufacturing process This is a very expensive
alternative which would need to be justified by the associated energy savings
53
7 SUMMARY OF CONCLUSIONS
The following is a list of the important findings produced from this study
(i) The edge loading accounts for a significant portion of the total cabinet load For the
test unit used in this study an 18 cubic foot top-mount refrigerator this load was
approximately 30 of the total load The load includes losses along the wall and door
flanges conduction through the door seal mullion loading with an electric anti-sweat
heater on and additional thennal input from an anti-sweat perimeter condenser tube
(ii) The presence of an electric anti-sweat mullion heater boosts the mullion loading by
a factor of approximately 5
(iii) The presence of an anti-sweat condenser tube around the perimeter of the refrigerator
increases the wall flange load by approximately 75
(iv) The presence of the door air damt reduces the temperature difference across the door
seal to 35 of the temperature difference between the interior and exterior
environments
(v) The hypothetical elimination of the additional load due to the electric anti-sweat
mullion heater reduces the edge loading to approximately 22 of the total cabinet
load
(vi) The hypothetical elimination of the load due to the anti-sweat condenser tube reduces
the edge loading to approximately 25 of the total cabinet load Ifboth anti-sweat
devices were not needed the edge loading would be further reduced to only 17 of
the total
(vii) During the course of this investigation it was concluded that the experimental and
numerical methods developed are applicable to most refrigeratorfreezers that are
produced today
t The portion of the door liner that extends into the cabinet along the wall
54
REFERENCES
Braswell A 1988 Impact of CFC Regulations on the Air Conditioning and Refrigeration Industry International Jow-nal ofRefrigeration Vol 11 No6 p 385
Cabot Corporation 1987 CAB-O-SIL Fumed Silica Properties and Functions Tuscola n pp 12-15
Clausing A M 1983 Natural Convection Correlations for Vertical Surfaces Including Influences of Variable Properties ASME Jow-nal ofHeat Transfer Vol 105 No 1 pp 138-143
Incropera FP and Dewitt DP 1985 Fundamentals ofHeat and Mass Transfer Second Edition John Wiley and Sons New York
Ingersoll LR Zobel OJ and Ingersoll AC 1954 Heat Conduction with Engineering and Geological Applications McGraw-Hill Book Company New York
Little AD Inc 1982 Refrigerator and Freezer Computer Model Users Guide Cambridge Massachusettes
Micropore International Ltd Microtherm Thermal Insulation Worcestershire England Section 1
Nix GH Lowery GW Vachon RI and Tanger GE 1967 Direct Determination of Thermal Diffusivity and Conductivity with a Refined Line-Source Technique Progress in Astronautics and Aeronautics (Vol 20) Thermophysics ofSpacecraft an Planetary Bodies Academic Press New York pp 865-878
Nix GH Vachon RI Lowery GW and McCurry TA 1968 The Line-Source Method Procedure and Iterative Scheme for Combined Determination of Conductivity and Diffusivity Thermal Conductivity Proceeding of8th Conference
Ozisik MN 1980 Heat Conduction Wiley-Interscience Publishing New York pp 486-487
Staley D 1992 Personal Communication Graduate Research Assistant University of Illinois Urbana
Turiel I Heydari A 1988 Analysis of Design Options to Improve the Efficiency of Refrigerator-Freezers and Freezers ASH RAE Transactions Vol 94 Part 2
Van der Held EFM and Van Drunen FG 1949 Physika Vol 15 No 10 p 865
White PM 1988 Heat and Mass TranSer Addison-Wesley Publishing Reading Mass pp 145-160
55
APPENDIX A FUMED SILICA INVESTIGATION
A ~ 1 Introduction
Fumed silica is a micro-porous powder comprised of submicron particles of amorphous
silica bonded together in a cellular structure Several grades of silica are available offering
a selection ofdifferent grain sizes and chemical treatments Fumed silica is commonly used
to provide thickening thixotropy suspension and other related properties in liquid
systems In dry systems it is used to promote free flow frictionizing and anti-blocking
properties Thus it is a versatile additive in materials such as inks coatings adhesives~
and silicon rubber (Cabot Corporation 1987)
The thermal insulating properties of this material have been somewhat less widely applied
however fumed silica as an insulation displays some interesting properties Fumed silica
insulations are commercially available and have become a more popular material for certain
specific applications In this section the results of an investigation of the thermal
properties of one type of fumed silica is presented
A2 Thermal Properties
As an insulator fumed silica uses the microporous principle to reduce thermal conduction
to the theoretically lowest possible levels (Micropore International Ltd 1988) Most
conventional insulations rely upon voids normally occupied bj alt aS the meanS ot
minimizing heat transfer through the material Therefore it is important to maintain these
voids for maximum insulation Fumed silica is comprised of tiny spheres with diameters
of the same order of magnitude as the mean free path of the molecules in the air
Therefore when these spheres are packed closely together gaseous conduction and
convection are minimized The cell size is sufficiently small to keep convective currents
from forming and to trap gas molecules to rebound elastically thereby not imparting their
energy to slower moving molecules In addition solid conduction is minimized by the fact
that silica is a material with intrinsically low thermal conductivity These unique properties
make fumed silica an attraCtive alternative to conventional insulations
56
A3 Experimental Method
Thennal conductivity and thennal diffusivity are the properties detennined from our
experimental study Many methods exist for establishing the thennal properties of a given
substance Both steady-state and transient procedures are available The hot-wire method
is a the transient procedure used in this study
The practical form of the hot-wire method is given by Van derHeldand Van Dronen
(1949) who used it to detennine conductivities of liquids Nix et al (1967) elaborated to
give a method for the simultaneous detennination of both thennal conductivity and thennal
diffusivity Therefore it is possible to detennine both conductivity and diffusivity by
passing a known amount ofcmrent through a heater wire embedded in the test material and
recording the temperature at a point on the wire and at a fixed point from the wire over the
period of the test From the temperature history of the point contiguous to the hot-wire the
conductivity can be detennined directly From the temperature history of the point at a
fixed distance from the hot-wire the diffusivity may be computed Both procedures are
outlined in the following section
A4 Theory
The temperature at any point in an infinite solid containing a line heat source of constantshy
rate is a function of the position time from initiation the thennal conductivity of the
material and the magnitude of the source This is shown mathematically by Ingersoll et aI
(1954) The cylindrical temperature field is expressed as
T=~l- exp-x2) dx (Al)21tk x
II
In series fonn
(A2)T=~[-amp-lnp+L-L+L_ ]21tk 2 21 4middot2 63
57
where
q = Heat input per unit length of wire [W1m]
k = Thennal conductivity of the material [Wm-K]
a = Thennal diffusivity of the material [m2s]
t = Elapsed time from heat liberation [s]
r = Radial distance from line-source [m]
Ce = Eulers constant (05772157 )
The temperature change between two times tl and t2 is accurate to better than one percent if
the value of ~ is less than 016 for a point very close to the line-source
(A3)
Equation (A3) is used in this case to detennine the thennal conductivity since the
diffusivity a and the radial distance T no longer appear in the relation Therefore
knowing the temperature at two different times during the test gives the conductivity
directly given that the value of ~ remains small This is achieved by choosing a point very
near if not contiguous to the hot-wire itself In our study a graphical method is used to
detennine the conductivity If the temperature versus the natural logarithm of the time is
plotted a straight line should be seen whose slope is equal to q4nk
Once the conductivity of the material is detennined the diffusivity can be found by the
method proposed by Nix et aI (1968) The temperature at a fixed and known distance
from the hot-wire must be monitored over the time period of the test Now since ~ gt 016
the diffusivity does not drop out of Equation (A2) Rewriting Equation (A3) as
(A4)
where
~2 ~4 ~6 ]r(~)= [ -~-ln~+---+-- (A5) 2 211 4middot2 6middot3
58
therefore (A6)
Using the temperature at the fixed location as an input Equation (A6) can be solved iteratively by means of Newton-Raphson technique to find the parameter ~ and thereby
yielding the thermal diffusivity a
AS Test Apparatus
Figure A1 is a sketch of the test apparatus used to collect thermal property data This
device provides a wide range of silica densities for packed tests Each half of the apparatus
is packed separately to the same density and then pressed together sandwiching the heater
wirethermocouple assembly between them
Remove bottom plate and press together with right half
Insert heater wirethermocouple assembl)
Remove bottom plate and press together with left half
Compact both halves to same density
Fig AI Fumed Silica Test Apparatus
Prior to loading the unpacked silica into the test cylinders the mass is carefully recorded
Each test cylinder has graduated marks to allow the volume of the sample to be computed
The density is then computed from the measured mass and volume At higher densities it
59
is sometimes necessary to load and compact several times Figure A2 is a schematic of the
heater wirethermocouple assembly and the entire test facility
Switch
Ammeter
Power Source
Cylindrical Test Section
Thermocouple for Conductivity
Data Acquisition System
Thermocouple for Diffusivity
Fig A2 Fumed Silica Test Facility Schematic
The heater wire used for all tests is 30 A WG nichrome wire with a nominal resistance of 2214 Wm Both thermocouples are type T 36 A WG Once the test sample is in place
the switch is closed allowing cUITent to pass through the heater wire The heat input per
unit length of the wire is determined from
(A7)
where q = Heat input per unit length of wire [Wm]
I = The input cUITent [Amps]
R = Heater wire resistance per unit length [Wm]
60
Knowing the heat input per unit length the temperature contiguous to the heater wire and
the temperature at a fixed distance from the heater wire over the duration of the test eqs
(A3) and (A6) can be solved This yields the conductivity and diffusivity respectively
A6 Results
All results presented in this section are from tests petfonned with a material sample donated
by Cabot Corporations Cab-O-Sil Division The silica is an untreated sample EH-5 with
a bulk density of 25 Ibsft3 and a nominal particle diameter of 70 angstroms Several tests
are petfonned at various densities The thermal conductivity is determined graphically as described above while the diffusivity is determined using a Fortran code to pe~orm the
Newton-Raphson iteration also outlined in Section A4
A total of seven different bulk densities are tested Each test consists of three runs at three
different power levels The temperature history is recorded for both thermocouples
Figure A3 is a plot of the temperature for the duration of a typical test for unpacked silica
70~--~----+----r----~-----~----+----r
10001
middot middot middot o 05 Ampsmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddot o 04 Ampsi ~ i
I i I I i oo~ct 60 IIJatr-T50
1 LL~40
1 ~ 1 010 1 ltgtom
JPi i30 i 0I1 o 03 Amps 1 I I
20~--~----+----r----~-----~----+----r
-10 o 10 20 30 40 50 60 70 Time (sec)
Fig A3 Time vs Temperature for Unpacked Run
61
To graphically detennine the thennal conductivity the temperatme data must be plotted
against the natural logarithm of time Figure A4 gives this plot along with the equations
that represent linear curve-fits to the straight portion of each curve
70~----~--------+------+--------~----~----~--------+-----~
60 ~ =l-LL-~--o T ~ 86839 ~ 1376 ~(t) I
50 ---f--H-deg--tfjtshy ~ T =11108 + 97346 m(t)
40 IT_oroJ~-
30 middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotImiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotsectmiddotmiddotmiddotmiddotmiddotImiddotmiddotmiddotmiddotmiddotmiddotmiddot~middotmiddotmiddotmiddot109~~Q9 T= 18431~ + 493 ~(t) 0
~ e i i i
20~----~--------+------+--------~---------~~----+------r
05 1 15 2 25 3 35 4 45 In (time)
Fig A4 Natural Log Time vs Temperature for Unpacked Run
All three curves should yield the same conductivity for the sample The conductivity is
detennined from the following relation
k= 12R (A8)4n(slope)
Table AI gives the average conductivity for each density level This is the average for the
three input cmrents used These results are also shown graphically in Figure A5
62
Table AI A verage Fumed Silica Conductivity for Various Bulk Densities
est
1
2
3
4
5
6
7
0024
0023
0022 -~ ct 0021
~ e 002
~
0019
0018
0017
i
~i
I I I I Imiddotmiddotmiddot_middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotimiddot_middotmiddot middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotimiddot-middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot
1i111
~ ~ iii
_I_1_1_1
I I I I I middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot middotmiddotmiddotmiddotmiddotmiddotmiddotfmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddot -r-t-o-rldegoo---shy
25 3 35 4 45 5 55
Density (lbsff)
Fig AS Conductivity vs Bulk Density
From the temperature data collected from the second thennocouple the thennal diffusivity
is computed (see Section A4) This thennocouple lies 3 mm (0118 in) from the heater
63
wire The output from the diffusivity iteration is provided in Table A2 A graphical
representation is given in Figure A6
Table A2 Average Fumed Silica Diffusivity for Various Bulk Densities
Test
Average Diffusivity m2s (ft2Jhr)
1 210 x 10-7 (000813)
2 166 x 10-7 (000643)
3 159 x 10-7 (000616)
4 155 x 10-7 (000600)
5 153 x 10-7 (000592)
6 No Data Available
7 151 x 10-7 (000585)
00085 -+----+-----f----+----+----+--_+_
I
middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1 ~0008
I I I I ~
I middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotfmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot Tmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot ~ 00075
~-shyf i ~ ~ ~ i ++middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotfmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot0007 i iii
~ rn ~ ~ i i~
(jj bullbullbullbullbullbull1bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullJLbullbullbullbullbullbullbullbullbullbullj ~ 00065o ~ middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot0006
I I I 00055 -+----+-----f----+----+----f--_+_
25 3 35 4 45 5 55
Density (lbsff)
Fig AS Diffusivity vs Bulk Density
64
A7 Conclusions
The primary conclusion from this experimental study is the fact that the thennal insulating
properties of fumed silica powder increase as the bulk density of the material increases
Although this study presents a limited range of density values the trends that were
expected are seen to be true The conductivity values are expected to reach and even
surpass those of CFC-blown foams that are used in household refrigerators Further
testing is needed to provide data that supports this expectation In addition testing in this
study was strictly limited to a single variety of silica This particular type of silica is not
necessarily the best candidate for thermal insulation applications Silica powders are by
nature hydroscopic This affinity for water has adverse effects on its thermal insulating
properties However silica powders are now produced with a special treatment which
transforms the material into a hydrophobic material Therefore if these new materials
maintain the thermal properties and density trends of the hydroscopic type they become
even more preferred insulators Once again data needs to be obtained to support this
notion Fumed silica offers a competitive alternative to the existing CFC-blown foams
without the obvious environmental drawbacks It is completely inert recyclable and
reusable It also competes well when comparing cost values CFC-blown foams are
between 003 - 007 $ft2_R-Value whereas fumed silica powder are between 005 -025
$ft2-R-Value The discrepancies are close enough to merit true consideration
AS Thermal Diffusivity Newton-Raphson Iteration Source Code
program difsivty implicit none double precision condqtime(lOO)temp(lOO)guessradiusalpha
+ dif(lOO)sumavedifgcurrentmasslengthpi + density integer nikrun OPEN (2file=Oiffusivityoutlposition=rewind) OPEN (3file=Oiffusivityinposition=rewind) OPEN (4file=Oiffusivityout2position=rewind)
print Enter input current in amps readcurrent printEnter calculated conductivity in Wm K readcond print Enter thermocouple distance in meters readradius print Enter mass of sample in grams readmass print Enter compacted length of sample in em readlength print Enter number of timetemperature data points
65
c
readn 5 print enter initial quess for beta
readquess c
pi=31415927 q=currentcurrent2214 density=(mass1000)laquopi4)(003844)(lenqth100raquo
c c check to see if converqence will occur c print Enter data point l c print (time and temp with a blank separatinq the two) c readtime(1)temp(1) c call diffus(condqtime(1)temp(1)quessradiusalphaq) c printinitial q=q c if (abs(q) qt 05) then c qoto5 c endif c
do 10 i=1n read(3) time(i)temp(i)
10 continue c
print print Input Current= current print write(2) Input Current= current write (2 )
c sum=OO do 20 k=1n call diffus(condqtime(k)temp(k)quessradiusalphaq) print Diffusivity for data pointk =alpha write(2) Diffusivity for data pointk =alpha write(4) alpha dif(k)=alpha sum=sum+dif(k)
20 continue c
avedif=sumn c
print print print INPUT print Conductivity=cond Wm K print Heater Input=q Wm print Thermocouple Distance=radius m print- print OUTPUT print Sample Density=density kqm3 print Averaqe Diffusivity=avedifmiddot m2s
c write(2) write(2) INPUT write(2) Conductivity=cond Wm K write(2) Heater Input=q Wm write(2) Thermocouple Distance=radius m write (2 ) write(2) OUTPUT write(2) Sample Density=density kqm3 write(2) Averaqe Diffusivity=avedif m2s
c c
pause stop
66
end
subroutine diffus(condqtimetempguessradiusalphag) implicit none double precision condqtimetempbeta(100)radius
+ f1f2f1pf2ptempf2tempf2pggppialphaCe + signfactol integer jkmn
c Ce=5772157 pi=31415927 beta (1) =guess tol=l j=l
c c begin Newton-Raphson iteration to find beta and ultimately alpha c
while (tol gt 0001) c print betaj =beta(j)
f1=-Ce20 - log(beta(j)) flp=-l Obeta (j) f2=00 f2p=00
c c start loop to compute the summations for f2 and f2 prime
do 10 k=2162 m=k2
c this loop gives the factorial for the kth term fac=10 do 5 n=lm
fac=facn 5 continue
sign=(-1)laquok+2)2) tempf2=laquobeta(j)k)sign)(kfac) tempf2p=laquobeta(j)(k-1))sign)fac f2=f2+tempf2 f2p=f2p+tempf2p
10 continue
c c compute the value of G and G which are both functions of beta c these will be used to update beta in the Newton-Raphson iteration c where beta(n+1)= beta(n)- GG
g=laquo20picondtemp)q)-(f1+f2) gp=- (flp+f2p)
c print g=g c here we check to see if the convergence criterion suggested c by Nix is met for the initial beta chosen if not we must jump out of loop c if (j eq 1) then c if (abs(g) qt 05) then c printconvergence not satisfied c printtry a s~aller guess for beta c return c endif c endif c c update the value of beta and compute a tolerance value c that will be used to check for convergence
beta(j+1)=beta(j)-(ggp) tol=abs(beta(j+1)-beta(j))
67
j=j+1 c protect against infinite looping
if (j eq 100) then goto 101
endif repeat
c c if the iteration converges then compute the value for diffusivity
alpha=(10(40timeraquo(radiusbeta(jraquo2
c c
101 return
68
APPENDIX B ONE-DIMENSIONAL SIMULATION SOURCE CODE AND OUTPUT
B1 Source Code
CPROGRAM FrigWall--Steady-State Heat Conduction with Convective and CRadiative Heat Transfer from interior and exterior surfaces C Programmed by AM CLAUSING
LOGICAL SI DIMENSION RA(2)XNU(2)R(2)H(2)HR(2)TF(2)TW(2)DT(2) COMMON AXLWXLC(2)HC(2)T(2)XKWBETANMAXSIE(2)SIGMA
CDetermine- direction of output read and print input data NCASE=l
1 CALL DATAIN(NCASEIUOUT) NCASE=NCASE+1 QOLD=O TW(1)=T(1)+1(T(2)-T(1raquo TW(2)=T(2)-1(T(2)-T(1raquo
CCalculate wall resistance RW=XLWXKWA DO 3 N=lNMAX DO S J=12
CCalculate the radiative equivalent heat transfer coefficients HR(J)=SIGMAE(J)(T(J)2+TW(J)2)(T(J)+TW(Jraquo
C Calculate the film temperatures TF(J)=(T(J)+TW(Jraquo2
CCalculate the convective heat transfer coefficients CALL GASPT(lTF(J)RHOXMUXKCPGRBPRIER) DT(J)=ABS(TW(J)-T(Jraquo RA(J)=PRGRBXLC(J)3DT(J) IF(RA(J) LT1E9) THEN
XNU(J)=0S2RA(J)2S ELSE
XNU(J)=09RA(J) 3333 ENDIF H(J)=XNU(J)XKXLC(J) IF(HC(J) NE O) H(J)=HC(J)
CCalculate surface resistances R(J)=l(H(J)+HR(JraquoA
S CONTINUE CCalc~late total resistance heat flow rate and surface temperatures
RT=R(1)+R(2)+RW Q=(T(2)-T(1raquoRT TW(l)=T(l)+QR(l) TW(2)=T(2)-QR(2)
CCheck for convergence If solution has converged exit loop ERRQ=ABS(Q-QOLD)100Q QOLD=Q IF(ERRQLT OS) GOTO 7
3 CONTINUE 7 WRITE (IUOUT 101) Q ERRQ (H (J) HR (J) RA (J) XNU (J) TW (J) DT (J) R (J) RT
2 J=l2) 101 FORMAT( Q =F61 W10XERRQ =FS2 T12 hconvT22hradT33
2 RaT44NuTS2 TsurT62 DeltaTT72RRtotT10 [Wm2-KjT20 2 [Wm2-KjTS3 [KjT63 [Kj InsideF72F92E133F91 2 F101F91F113 OutsideF62F92E133F91F101F91F113) DO 9 J=l2 IF(HC(J) NE bull O) WRITE (IUOUT 103) J
9 CONTINUE 103 FORMAT( NOTE hconv(I1 ) was specified not calculated)
GOTO 1 END
69
C SUBROUTINE DATAIN(NCASEIUOUT) LOGICAL SI COMMON AXLWXLC(2)HC(2)T(2)XKWBETANMAXSIE(2)SIGMA DATA AXLWXKWXLCHCTENMAXSIGMA2990360245315 2 20277297 959510567E-8
CDefinition of NAM NAMELIST NAMAXLWXKWXLCHCETNMAXBETASI CHARACTER FNAME60CDATE9CTIME8 PARAMETER (IUIN=7)
CIF First Case Open Files Write Program Description and Date IF (NCASEEQ 1) THEN
WRITE (6 100) 100 FORMAT( TYPE NAME OF INPUT DATA FILE)
READ( (A) ) FNAME COpen input and output files
OPEN (7FILE=FNAME) REWIND 7
C OPEN (10FILE=Plots-FNAME) C WRITE(6122) Plots-FNAME C122 FORMAT( COMMA DELIMITED PLOTTING FILE IS A)
WRITE(6118) 118 FORMAT (T10 DIRECT OUTPUT TOT20 SCREENT36 Type 6
2 T20 OUTPUT FILET36 Type 8T20 PRINTERT36 Type 9) READ() IUOUT IF(IUOUTEQ8) THEN OPEN (8FILE=Answers-FNAME) WRITE(6120) Answers-FNAME
120 FORMAT( OUTPUT WILL BE WRITTEN IN FILE A) ENDIF CALL DATE(CDATE) CALL TIME(CTIME)
CWrite Program Description and Date WRITE(IUOUT102)CDATECTIME
102 FORMAT( Program FrigWallT60 Date A10 Version 8 August 1991T60 2 Time A9 Programmed by AMClausing) ENDIF
CRead and Write Input Data READ(IUINNAMEND=999) WRITE (IUOUT 104) NCASETXLCEXLWXKWA
104 FORMAT ( CASE NUMBER 12 2 Ambient Temperatures IK] InsideF616X OutsideF61 2 Characteristic Lengths 1m] InsideF626X OutsideF62 2 Surface Emissivities8X InsideF626XOutsideF62 Wall
Thickness 2 F63 mT27 ConductivityF63 Wm-K2x AreaF52 m2) RETURN
999 WRITE (IUOUT 199) 199 FORMAT ( ALL INPUT DATA HAS BEEN PROCESSED) 991 CLOSE(10)
IF(IUOUTEQ 8) CLOSE(8) STOP END
C SUBROUTINE GASPT(NGASTRHOXMUXKCPGRBPRIER)
C PROGRAMMED BY A M CLAUSING VERSION APRIL 1982 C PROPERTIES OF GASES IN SI UNITS(TGTO) OR ENGLISH UNITS(TLT O) C FUNCTIONAL REPRESENTATIONS USED ARE OF THE FORM Y=ATB C ARRAYS A AND B CONTAIN THE RESPECTIVE CONSTANTS C INPUT C NGAS - NGAS=l IS AIR NGAS=2 IS NITROGEN C T ---- ABSOLUTE TEMP (K) OR NEGATIVE OF ABSOLUTE TEMP (R) C OUTPUT C RHO -- DENSITY (KGM3) OR (LBMFT3)
70
C XMU -- VISCOSITY (KGM-S) OR (LBMFT-S) C XK --- THERMAL CONDUCTIVITY (WM-K) OR (BTUHR-FT-R) C CP --- SPECIFIC HEAT (JKG-K) OR (BTULBM-R) C GRB -- GBETAXNU2 (1M3-K) OR (1FT3-R) C PR --- PRANDTL NUMBER (DIMENSIONLESS) C IER -- ERROR PARAMETER C INFORMATIVE ERRORS C IER=l --- GAS NUMBER DOES NOT EXIST GAS IS ASSUMED TO BE AIR C IER=2 --- TEMPERATURE OUT OF RANGE OF PROPERTY SUBROUTINE C RESTRICTIONS C NGAS -- MUST BE l(AIR) OR 2 (NITROGEN) C T ----- T MUST LIE BETWEEN 150K AND 2100K FOR AIR AND BETWEEN C 83K AND 450K FOR NITROGEN RANGES ARE SPECIFIED WITH ARRAY R C
DIMENSION A(152)B(152)R(32) DATA A36411764E-61423E-399084178E20123 235064914E-62494E-329944985E195930 3 432491E-81239E-415534379E201137 4351618E-6221E-31031408E2084130 DATA B-1005814913800316-4639-09685 2 -999642981521962-4284023930 3 -10469389466-079-5102-0872 4 -10058058 834500239-4636-0265230 DATA R150400210083160450 IER=O IFlaquoNGASGTO) AND(NGASLT3raquo GO TO 1 IER=l NGAS=l
1 1=1 TP=T IF(TLT bullbull O) TP=-T18 IFlaquoTPLTR(lNGASraquo OR (TPGTR(3NGASraquo) IER=2 IF(TPGTR(2NGASraquoI=7 RHO=A(INGAS)TPB(INGAS) XMU=A(I+1NGAS)TPB(I+1NGAS) XK=A(I+2NGAS)TPB(I+2NGAS) CP=A(I+3NGAS)TPB(I+3NGAS) GRB=A(I+4NGAS)TPB(I+4NGAS) PR=A(I+5NGAS)TPB(I+5NGAS) IF(TGT O)RETURN RHO=RHO1602 XMU=XMUl 488 XK=XKl 731 CP=CP4187 GRB=GRB6357 RETURN END
B2 Output
Program FrigWal1 Version 8 August 1991 Programmed by AMClausing
Date Time
05-MAR-92 200227
CASE NUMBER 1 - Fresh Food Walls
Ambient Temperatures IK] Inside 2770 Outside 2940 Characteristic Lengths 1m] Inside 030 Outside 150 Surface Emissivities Inside 095 Outside 095
71
Wall Thickness 0045 m Conductivity 0027 Wm-K Area 242 m2
Q = 209 W ERRQ = 002
hconv [Wm2-K]
Inside 1 98 Outside 130
hrad [Wm2-K] 461 544
Ra
0488E+07 0459E+09
Nu
244 761
Tsur [K]
2783 2927
DeltaT [K] 13 13
RRtot
0077 0075
CASE NUMBER 2 - Fresh Food Door
Ambient Temperatures [K] Inside 2770 Outside 2940 Characteristic Lengths [m] Inside 030 Outside 150 Surface Emissivities Inside 095 Outside 095 Wall Thickness 0040 m Conductivity 0040 Wm-K Area 089 m2
Q = 117 W ERRQ = 001
hconv [Wm2-K]
Inside 218 Outside 144
hrad [Wm2-K] 463 542
Ra
0714E+07 0690E+09
Nu
269 843
Tsur [K]
2789 2921
DeltaT [K]
19 19
RRtot
0114 0113
CASE NUMBER 3 - Freezer Walls
Ambient Temperatures [K] Inside Characteristic Lengths [m] Inside Surface Emissivities Inside
2630 030 095
Wall Thickness 0056 m Conductivity 0027
Outside Outside Outside
2940 150 095
Wm-K Area 110 m2
Q = 14 3 W ERRQ = 003
hconv [Wm2-K]
Inside 226 Outside 143
hrad [Wm2-K] 397 542
Ra
0990E+07 0684E+09
Nu
292 841
Tsur [K]
2651 2921
DeltaT [K]
21 19
RRtot
0067 0061
CASE NUMBER 4 - Freezer Door
Ambient Temperatures [K] Inside 2630 Outside 2940 Characteristic Lengths [m] Inside 030 Outside 150 Surface Emissivities Inside 095 Outside 095 Wall Thickness 0040 m Conductivity 0040 Wm-K Area 034 m2
Q = 81 W ERRQ 002
hconv [Wm2-K]
Inside 259 Outside 1 64
hrad [Wm2-K] 400 538
Ra
0169E+08 0124E+10
Nu
333 967
Tsur [K]
2666 2906
DeltaT [K] 36 34
RRtot
0117 0110
72
__ ___
APPENDIX C TEST REFRIGERATOR DESCRIPTION
The test refrigerator is a White-Westinghouse model RT193MCWO 186 cubic foot
capacity top-mounted unit It is equipped with full automatic defrost The cycle time for
this unit is approximately 50 The unit also has two anti-sweat devices An electric
heater is located in the mullion region to prevent frosting between the freezer and the fresh
food compartments Also a condenser tube runs around the entire outside perimeter of the
unit embedded beneath the steel all flange Figure C1 illustrates these features
~1-- 0787 m (31)__
~ r_----------------------
1581 m
Fig CI Location of Anti-sweat Devices and Overall Dimensions of Test Refrigerator
73
Under test conditions the refrigerator and freezer are filled with milk containers full of
water These containers provide sufficient thennal mass to minimize temperature
fluctuations dming experimental runs Twenty gallons are present in the fresh food
compartment and 6 gallons are in the freezer
Figures C2 through C5 give the detailed dimensions of the fresh food compartment and
the freezer All dimensions are in millimeters and are obtained directly from the unit
Dimensions are estimated to be accurate to within plusmn 3 mm
697
762
1
305
717
Fig C2 Fresh Food Compartment Interior Dimensions
74
1127
Fig C3 Fresh Food Door
75
675
381
Fig C4 Freezer Interior Dimensions
432
Fig CS Freezer Door
76
APPENDIX D DATA ACQUISITION AND CONTROL SYSTEM
Corresponding with the construction of the experimental apparatus was the purchase and
assembly of a data acquisition and control system The system itself was designed to meet
the needs of a variety of experiments and is therefore a very flexible system
The system consists of six DC power supplies a data acquisition chassis a computer a
rack ofdigital relays and a variety of analog and digital inputs and outputs A data
acquisition and control software package orchestrates the interactions between these
components and regulates outgoing signals as well as providing data storage
External signals enter the system through a Keithley 500P data acquisition chassis These
signals consist of voltage and current measurements from the power supplies as well as
thermocouple voltages At present a total of ninety-six thermocouple inputs are available
with an optimal resolution of +0012 degrees C The addition of more thermocouple input
boards could expand the capability to 128 inputs Also special boards can be installed to
allow strain gauge thermistor digital or other standard data acquisition functions The
Keithley chassis can contain a total of nine interface boards and its l~bit AID conversion
allows for very high resolution
The six DC power supplies consist of two Hewlett Packard and four Sorensens with a
combined power of 7560 watts The Sorensens are rated at 0-150 volts at a maximum of
12 amps while the Hewlett Packards produce 0-60 volts at a maximum of 3 amps All of
the power supplies are computer-controlled however the Sorensens may be operated
manually ifdesired Voltage measurements from the power supplies are fed into the
Keithley acquisition chassis and are then routed to the computer A voltage from the
computer is buffered and fed into the control circuits of the power supplies This voltage
completes the loop and controls the output voltage of the power supplies The software is
responsible for reading the output voltage of the power supplies comparing it with the
intended setpoint and adjusting the control voltage as needed This arrangement allows the
user to vary the output voltage of the power supplies from within a program Computershy
controlled safety relays are in place to disconnect the power supplies should they stray too
far from the intended voltage setpoint Fig D1 displays the system
77
Thermocouple and Voltage Inputs
r
Computer Data Acquisition Chasis Intaface
00 Voltage and 1 r Current
Measurement
Computer
I I
Analog Control Signal
Digital Oulput Signals 5 6
Power Supply 4 Relay Rack
Power Supply 3 00000001 Power Supply 2
Buffered Analog100000001 Power Supply 1 Control Signal
1 2 3 4 5 6 - I
I00 00 )0 po po po
Ir Digital Outputs
Analog Outputs
Fig DI Data Acquisition and Control System
78
APPENDIX E EXPERIMENTAL RAW DATA AND PLOTS
E1 Temperature Profile Plots From Fixed Thermocouples
In this appendix the remaining tests for the fixed thennocouple testing presented in Section
41 are provided Figures E1 and E2 give the results from the fresh food compartment
and Figures E3 and E4 give the results from the freezer Notice the outdoor and interior
ambient temperatures are not the same as the two tests presented in Section 41
191
Run 2 ttl ~ i i
middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot
middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot-imiddotmiddot
TWall
middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotlmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot
-
Outdoor Ambient =210 degC Fresh Food Ambient =375 degC
-] _ Door ProfUe i -il- 0 Wall Profile
i 19
$-- - Tdo = 19078 - 001326x
l~l ~~i 189 i i a m
0 i -m-
i 188 middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot
187 ~ middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot 5 = 18989 - O02024x 1
F 186
~bullbullbullbullbullbullbullmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot185 i i
184 0 5 10 15 20 25
x (mm)
Fig E1 Steel Skin Temperature Plot for Fresh Food Compartment (Run 2)
79
191
19
189
a ~
i 188
187
5F
186
185
184 0
Run 3 I --D - Door Profile
middotmiddotmiddotmiddotmiddotmiddotmiddotmiddot-middotmiddotmiddotmiddot~middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotimiddotmiddot-middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddot 0 Wall Profile
i - i - - Tdo =19053 - 001384x or
=c-=r=-~-= 1 11=
~ n - 189S 001998 --t-shy-~~-
5 10 15 20 25
x (mm)
Fig E2 Steel Skin Temperature Plot for Fresh Food Compartment
186
184
182
- ~- 18
178
~ 176
174
172 0
(Run 3)
Run 2 l --0 - Door Profile
middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot~middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotdrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotf 0 Wall Profile - 1- - middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot--m
- - T =18544 - 002398x i - i door rb
~i
i bullbullbulli _ bull imiddot
~ I TWall =18182 - 003542x tmiddotmiddotmiddotmiddot middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotlmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot
~ n~l l
5 10 15 20 25
x (mm)
Fig E3 Steel Skin Temperature Plot for Freezer (Run 2)
80
--a 0
I5F
186
184
182
18
178
176
174
172
Run 3 I --0 - Door Profile
middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotCmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotl 0 ~a1l Profile
ttl __ OJ 1 1 middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotfmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotlmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot -shy - Td = 18411 - 002272x ibullbullbullbullbullbullbull-bullbullbullbullbullbullbullbullbulli
oor ~
rp bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbull bull 11_1
I I middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotimiddotmiddotmiddotmiddot middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotImiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot
~ _l
Outdoor Ambient =208 degc Freezer Ambient = -93 degc
0 5 10 15 20 25
x (mm)
Fig E4 Steel Skin Temperature Plot for Freezer (Run 3)
E2 Thermopile Data Reduction
The data from the thennopile tests consist of an output voltage (mV) measured with a
Keithley multimeter which has a resolution of 1 m V The procedure required to translate
this voltage into a temperature difference follows
1 Read the output voltage in millivolts
2 Detennine the average skin temperature from fixed thennocouple data
3 Use the reference table and the average skin temperature to determine the conversion factor in Vrc
4 Convert to temperature difference as follows
1T = ____o_utpu_t_vo_l_tag-e___
ofjunctions x conversion factor
81
Table EI Thermopile Raw Data
ffOutput fzOutput ff Ave Skin Temp fz Ave Skin Temp mV mV CC CC
Roo wall door wall door wall door wall door
1 0052 0048 0045 0050 189 191 177 183
2 0054 0052 0046 0048 187 189 176 182
3 0056 0053 0046 0051 186 188 175 181 ff Conv Factor fz Conv Factor ff AT fzAT
Ilvrc Ilvre CC CC
Roo wall door wall door wall door wall door
1 40165 40181 40067 40116 026 024 037 041
2 40148 40165 40058 40107 027 026 038 040
3 40140 40157 40050 40099 027 026 038 040
Average Temperature Difference 0267 0377 0253 0403
from Thermocouple Reference Tables Based on the IPTS-68 US Dept of Commerce
E3 Experimental Determination of qwall and qdoor Details
The four heat fluxes are calculated using
-k M (El)q - m Ax
For 05 carbon cold rolled steel km =540 Wm K (312 Btuhr-ft-OF) Also Ax = OOlm (039 in) for all computations
0267degC 2 qwallff = 54 Wm-K 001 m = 14418 Wm
_ 0377 degc _ 2 qwallfz - 54 Wm-K 001 m - 20358 Wm
0~3~ 2 qdoorff =54 Wm-K 001 m =13662 Wm
82
0403degC 2 qdoorfz = 54 Wm-K 001 m = 21762 Wm
Compute the heat transfer rate according to Equation (B2)
q =qA=qhP (B2)
Where A is the cross sectional area of the steel casing that is perpendicular to the direction
of heat flow The area is the product of the steel skin thickness b and the total perimeter of
the compartment opening which is exposed to the room environment P Perimeter
definitions
Pwallff = llm + 076m +llm = 296 m
roJ D Pwallfz =O4lm + 076m + O4lm =l58 m
I ] I ~I Pdoorf( = llm + 076m + llm + 076m = 372 m
Pdoorfz =076m + O4lm + 076m + 041m =234 m
83
qwallff =(14418 Wm2)(65e-4 m)(296 m) =277 W
qwallfz =(20358 Wm2)(65e-4 m)(158 m) =209 W
qdoorff =(13662 Wm2)(65e-4 m)(372 m) =330 W
qdoorfz =(21762 Wm2)(65e-4 m)(234 m) =331 W
E4 Temperature Profile Plots From Mullion Data (Heater oro
The following plots are from the remaining runs for the mullion analysis presented in
Section 45 All data is taken from the exact center of the mullion
131
13 middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot-tmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotjmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotlmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot9middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotlmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot6middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddot T 11 f =12383 + 0019929x iii mu z
129 ~ middotImiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot[middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddota ~
i 128 middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot4middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot-j-middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotfmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotfmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot
127e ~
126 ~~~=H~~-~=HmiddotrI~ ++~11 Room Ambient =2250 degC125
1 1 i Fresh Ambient =515 degC iii i i Freezer Ambient =-603 degC
124
1 10
Fig ES Mullion Temperature Profile Run 2 (Heater Off)
Run 2
2 3 4 5 6 7 8 9
TIC
84
146
145
a 144 ~
i 143
5 ~ 142
141
Run 3 9 0
---r-r--deg-r-ideg-t-9--rshyiii ltD T 11 ff = 15173 - OOI71x mu bull
middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotfmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotImiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot6middotmiddot
1Tmull~fz =14062 + J0158211x JLt 1
Q 1 1 1 middotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1-middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddoti-middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotimiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotoot-middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot-I-bullbullbull~bullbullbullbullbullbullbullbullbullbullbull
iii middotiiimiddot-j Room
1Am~t = 21~1 degC
iii i 1 Fresh Ambient = 563 degC 1 1 1 1 1 Freezer Ambient = -153 degC
14~---+--~----r---+---~---+--~----r---+-
1 2 3 4 5 6 7 8 9
TIC I
Fig E6 Mullion Temperature Profile Run 3 (Heater Off)
127
126
125 a ~
i 124
123 e ~
122
121
12
1
Fig E7
i i CD middotmiddotmiddotmiddot----middotmiddot-r--middot---middotmiddotmiddotmiddotmiddotmiddot-lmiddot--------middotmiddotmiddotmiddotl-middotmiddot---middotmiddotmiddotmiddot---r---middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1middotmiddotmiddotmiddotmiddot---middotmiddot---middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot-r----middot1__ _-
I I I T mulIff = 1321 - 001532x middotmiddotmiddotmiddot------middott--------------tmiddotmiddot----middot----middotmiddot-1------middotmiddotmiddotmiddotmiddotmiddot---jmiddot-----middotmiddotmiddotmiddotmiddotmiddotmiddotmiddot-lmiddotmiddotmiddot---middotmiddotmiddot-----tmiddotmiddotmiddotmiddotmiddot--middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddot-----middotmiddotmiddot6middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot
I cent I I I I -~~~~-ro-Tr-
r-middotmiddotmiddotmiddotrTTr-middotrmiddotrmiddotrmiddot middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddott middotmiddotmiddottmiddotmiddot1middotmiddotbullbullbullbull fmiddotbullbullbullbullbullbullbullmiddot-fbullbullbullbullbullbullbullmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot
II Room Ambil =21~3 degC iii i i Fresh Ambient =551 degc iii i i Freezer Ambient = -681 degC
2 3 4 5 6 7 8 9 10
TIC I
Mullion Temperature Profile Run 4 (Heater Off)
85
10
111
iii i i 11
Fttul5
T mu
=J=~[rr~tl=rI=109
a ~ 108 -t-t-t-i~FFl~i~~
+-0amp_- -+_bullbullbullbullbullbullbullbull+ - bullbullbull 107 11 f ~ 10325 + 0021893x 1 1 1 ji
5 bull Z iii
------~-~-----~---i --L--l ---_l__ ---L-----_shy106 ~
105 -t---i--+-+-+-middot++-I-shyL1LLL Room Ambient = 2177 C104 iii i i Fresh Ambient =448 degC
Freezer Ambient = -644 degC 103
1 2 3 4 5 6 7 8 9 10
TIC
Fig E8 Mullion Temperature Profile Run 5 (Heater Off)
86
34
33 1 1 1 1 1 1 1 1------I---------middotmiddot--+middotmiddotmiddotmiddot------middottmiddot-------middotmiddotmiddotmiddottmiddot----------middotmiddotmiddot---middot---middot----tmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot---middotmiddott--middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot(middotmiddotmiddotmiddotmiddot--
32 11 f =1 2859 ~ OI~X j
Till ff =133013 j - 007124x mu
31
a ~ 30
i 5 ~
29
28
27
26
Tmullfz = 26944 + 014842x
mu t-tr l
25 middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotjmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotjmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotlmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1middot ~ u~ ~it
24 lllti1 ~ i i ~ i
0 Lower Limit
23
0 1 2 3 4 5 6 7 8 9 10
ES Temperature Profile Plots From Mullion Data (Heater On)
The following are the remaining plots from the mullion heater analysis presented in Section
46
TIC I
Fig E9 Mullion Temperature Profile Run 2 (CenterHeater On)
Run 2
T muz
1
87
l----+
29
middotmiddotmiddotgtmiddotmiddoti middot 0 upper Limit 28 Run 1
I
middotmiddotI o
Tmullfz
T muo
LL~4cb 0 Lower Limit27
middot~+ImiddotmiddotmiddotImiddotmiddotmiddottr9middotdJmiddotmiddotmiddotmiddot 26
t T = 29465 008022xmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddot1middotmiddotmiddotmiddotTmiddotmiddotmiddotmiddot[middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1middot mullffa 25~
i 24 =24837+ 013186x middotlmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot+middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotimiddotmiddotmiddotmiddotmiddotmiddotmiddotlmiddotmiddotmiddotmiddotmiddotmiddot iii i i
i _ Jbullbullbullbullbullbullbullbullbullbullbullbullbulli l _l ii 23
e 22~ 21 +I~=tt=l=fit
L~LLL Tm~llff = 23856 005858x20 11 f = 1803 + 02243x z -rmiddotmiddotmiddotmiddot1middot middotmiddot middotmiddot 1middotmiddotmiddotmiddotmiddotTmiddotmiddot middot-rmiddot19
18
0 1 2 3 4 5 6 7 8 9 10
TIC
35
34
33
32
a ~ 31
I ~
30
29
28
27
26
25
24
Fig EI0
---bull---i----bullbullmiddotmiddotmiddotmiddot--~--------middotmiddot-+------ j bullbullbullbull ---bullbullbullbull -i--__---
T 11 f =30063 + OI~x 1 T i 134 196 i
0068 1 38
muz tmiddotmiddot Ilff=middot bull x ltP lt1gt mu
=t=H=t+t=R=t= F-6~I-i~E
Tmullfz = 28103 + 014486x 1middot++middot1middot1
middotmiddotmiddot--middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotimiddotmiddotmiddotmiddotmiddotmiddotmiddot-middotmiddotmiddotmiddotmiddot+middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotbullbullmiddotmiddotmiddot-middotmiddotimiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot~middotmiddot
111111 0 Upper Limit iii iii 0 Lower Limit
0 1 2 3 4 5 6 7 8 9 10
TIC
Mullion Temperature Profile Run 3 (CenterHeater On)
Fig Ell Mullion Temperature Profile Run 1 (LeftHeater On)
88
a
29
28
27
26
25~
i 24
23 e
22~ 21
20
19
18
Fig E12
i l middot middotmiddotmiddotmiddotlmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot+ 0 Upper Limit T 11 f =24474 + 011288x i imu bull z o Lower Limit
=tplusmntplusmnfrplusmnplusmnplusmn ~ I I I I Tmull ff ~ 28793 - o0784x
middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddott----middot------middotmiddotimiddot----middot-middotmiddot--middot-~-middotmiddotmiddot--middot----middotmiddot)middot
=ii=t=1=P-Ltplusmnt iii i T = 25599 - 00689xIfmiddotTTTmiddotmiddotrmiddot ~Ullff iii
T l1f =20552 + 01676x i~~imiddotimiddotmiddot
==~LL L LLLLL i i 1 ~ 1 ~
0 1 2 3 4 5 6 7 8 9 10
TIC I
Mullion Temperature Profile Run 2 (LeftlHeater On)
33 iii i i
-middot--middot(---middotmiddot--middotmiddot--middotmiddot+---middot-middotmiddotmiddotmiddot-middotmiddotmiddot~-middot--middot-------middoti---middot------~ o Upper Limit 32 Run 3
t bullbullbull +
Tm~llfz
T mu
1 1 1 1 1 o Lower Limit ~~31
=2713 ~ 0113~x j11Li30
a T ulff =30658 - 006506x 29~
IktlJ2~Li 28
27 e
26 =l=tt=tmiddotmiddottmiddott+~middot+=t=~ middotmiddot jmiddotjmiddottmiddottmiddotjmiddot T = 28288 - 00603x
iii i mullff 24
25
middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotQmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot+middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot~middotmiddotmiddot middotmiddotmiddotmiddotmiddotmiddotmiddotmiddot~middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot+middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot 11 fz = 2377 ~ 01788x IL11123 i i
22
0 1 2 3 4 5 6 7 8 9 10
TIC I
Fig E13 Mullion Temperature Profile Run 3 (LeftHeater On)
89
31
30
29
ltP ~u
J
1 T
-~Lti=t~-t--t i~+--Ij Tmu1lff =31473 middot005222x 28
1 1 1middot 1 l i l i bullbullbullbullbullbullbull__ bullbullbullbull_ bullbullbullbullbullbullbull~_bullbullbullbullbullbullbullbullbulla bullbullbullbullbullbullbullbullbullbullbull a 27
~ Tm~llfz = 26857 + 01734x _~__+_+II i
26
bullmiddotmiddotbullbullbullmiddotmiddotbullibullbullbullbullbullbullbullbullbullbullbullmiddotmiddotmiddotbullbullbullbullbullbullbullbullmiddotmiddotmiddotmiddot bullbullbullbullbullbullbullbullbull-i-~-i-ii25
JJ$~L-f$9 5 24
~ 23 middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotlmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot+middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot~middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot+middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1-middotmiddot T mllff =25622 bull 002~7X c-bullbullbullbullbullbullbullbullbullbullbullbull+ ~~ 22 rp 1 1 i i 1 1 1
21 = 19464 + 02548 jmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddott Upper Limitmullfz xii 0
4-bullbullbullbullbullbullbullbullbullbullbullbullimiddotmiddotmiddotbullbullbullbullbullbullmiddotf20 i 1 ~ 1
19
0 1 2 3 4 5 6 7 8 9 10
TIC I
Fig E14 Mullion Temperature Profile Run I (RightHeater On)
33 i
middotmiddotmiddotmiddotlaquomiddotmiddotmiddotmiddot------------------------------- c--------middotmiddotmiddot-middot-----------middotmiddotmiddot---middotmiddot--------l-----middot-----I-----32
= 2757 + 017006x ILLJ1
a
31
30
29~
i 28
Run2
TmulIfz
T~ulIfz ~
-~t=ii~Ii~~~~ i
27 middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot9-middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotT~~middotmiddotmiddotmiddotmiddot2s944-middot~middotmiddotO0278~middotmiddote 26~ r~rrTt+rr25
24 2320~ + O~S4x middotmiddotlmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotjmiddot ~ u~ L~t 23 middotmiddotmiddotmiddotmiddotmiddotmiddotmiddot~middotmiddotmiddotmiddotmiddotmiddotmiddot+middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot+middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot+middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotImiddotmiddotj 0 Lower Limit
22
0 1 2 3 4 5 6 7 8 9 10
TIC I
Fig EIS Mullion Temperature Profile Run 2 (RightlHeater On)
90
33 i i ~ _______ _ _~____ __ __-i--bullbullbullbullbullbullbullbull-t------ -- uu__~ ~ --~32
=1268931+ 0~4~14X 111131
30
a 29~
I 28
Run3
Tmullfz
i t+ I T
m
mnplusmn~~27 6 i 1 i 1 +++ T mullff =28912 - 002938x 26~ +middotmiddot++Imiddotjmiddott-25
= 22996 + 02312x 1middotmiddot+ 24
~~~~L lL1 0 ~23 ill 0 22
0 1 2 3 4 5 6 7 8 9 10
TIC
Fig E16 Mullion Temperature Profile Run 3 (RightHeater On)
91
APPENDIX F NUMERICAL SIMULATION EQUATIONS AND CODE
F1 Finite-Difference Equations
Figure Fl is a generic resistor network that is used as a base for all the finite-difference
equations The general fonn is
(Fl)
r----II ij+l
J
i j-l L ______--J
Fig F1 Generic Nodal Resistor Network
This makes it easy to simply plug in the different resistors for the different regions of the
section There are twelve resistors total The following table summarizes the resistors
needed to complete the model
Table F1 Model Resistors
Description Resistance [CIW]
Interior insulation x direction Rl= dx dymiddotkinsmiddotb
92
dyInterior insulation y direction R2= dx-kins-b
dySteel parallel with insulation y direction R3= km-dm-b + kins-(dx -dm)
dxR=Steel parallel with insulation x direction km-dm-b + kins-(dy -dm)
dyRs=Plastic parallel with insulation y direction
kp-dp-b + kins-(dx -dp)
dxPlastic parallel with insulation x direction R6= kp-dp-b + kins-(dy -dp)
heffa- (~- dm) + kinsSteel to exterior x direction R7= 2
heffo-kins-dy-b
heffa- (dY - dm) + kinsSteel to exterior y direction R - 28shyheffo-kins-dx-b
hefti- (dY _dm) + kinsSteel to interior y direction R9= 2
heffi-kins-dx-b
hefti- (~- dp) + kinsPlastic to interior x direction RIO= 2
heffi-kins-dy-b
Rll = hefti- (dJ -dP) + kinsPlastic to interior y direction
heffi-kins-dx-b
93
Steel skinplastic skin interface
2middotkmmiddotdmmiddotkpmiddotdpmiddotdxR12=----------------------~~----------------
2middotkmmiddotdmmiddotkpmiddotdpmiddotbmiddot(dy -dp) + (kpmiddotdp + kmmiddotdm)middotbmiddotdx2
F2 Wall Simulation Source Code
Program FiniteDiff
c This program simulates the conductive heat transfer through the wall section c of the refrigerator near the door gasket using Guass-Siedel iteration c The program allows for flexibility in the geometry and material properties c The program is a steady-state model
cVariable Definitions
c km = conductivity of the outer metal skin (Wm-K) c kins = conductivity of the polyurethane foam insulation (Wm-K) c kp conductivity of the inner plastic skin (Wm-K) c dm = thickness of the metal skin (mm) c dp = thickness of the plastic skin (mm) c b = depth of the section (m) c heffo = effective heat transfer coefficient on outside surfaces (Wm2-K) c heffi = effective heat transfer coefficient on inside surfaces (Wm2-K) c sl width of wall inSUlation (mm) c s2 length of wall section (mm) c s3 seal indentation (mm) c s4 seal width (mm) c s5 distance metal skin travels into cabinet (mm) c s6 distance platic skin travels out of cabinet (mm) c ns = number of nodes corresponding to the s regions above c rs = network resistors (m-eW) c i = integer values of distance along the x axis c j = integer values of distance along the y axis c imax maximum integer value in x direction c jmax maximum integer value in y direction c iter total number of iterations to converge c loop convergence flag c Qinl Heat flux per unit length across the outer boundary (Wm) c Qin2 Heat flux per unit length across the inner boundary (Wm) c Qdif Qinl - Qin2 (Wm) c Qpdif = percent difference between the heat fluxes Qinl and Qin2 c Ti Inside ambient temperature (e) c To = Outside ambient temperature (e)
cDeclare Variables
INTEGER nln2n3n4n5n6ijloopimaxjmaxiter INTEGER clflaglflag2 REAL kmkinskpdmdpdxdyheffoheffi REAL TiToQdifQpdifQinlQin2 REAL sls2s3s4s5s6lenoutlenin REAL rlr2r3r4r5r6r7r8r9rlOrllr12 REAL T(-1lOl-1lOl)bqlDsumlsum2 REAL Qm(lOl)qfluxm(lOl)fluxo(OlOl)fluxi(OlOl)
94
REAL fluxcen(0101)pfluxcen(0101)pfluxo(0101) REAL pfluxi(0101)pmaxdifoneDtolaq2Dqedge1
OPEN (10file-2Dcode(v11)out1position-rewind) OPEN (11file-2Dcode(v11)out2position=rewind)
cTest Parameters
c thermal conductivity of the outer metal skin (Wm K) km-540
c thermal conductivity of the wall insulation (Wm K) kins=0021
c thermal conductivity of the inner plastic skin (Wm K) kp=015
c thickness of the metal skin (mm) dm=065
c thickness of the plastic skin (mm) dp=25
c effective heat transfer coefficient on outside surfaces (Wm2-K) heffo=681
c effective heat transfer coefficient on inside surfaces (Wm2-K) heffi=610
c width of section (mm) sl=450
c length of section (mm) s2=2000
c depth of the section (m) b=10
c inside ambient temperature (C) Ti=95
c outside ambient temperature (C) To=210
c unit conversions dm=dm1000 dp=dp1000 sl=sl1000 s2=s21000
c specify 1-dimensional tolerance (t) oneDtol=30
cMesh Parameters
c specify the following nodal mesh parameters n1=20 n2=80 n3=1 n4=9 n5=10
c various mesh dimensions dx=sln1 dy=s2n2 s3=n3dx s4=n4dx s5=n5dx s6=sl-s5-dx n6=s6dx imax=n1-1 jmax=n2-1
cInitialize temperature matrix
DO 10 j=-1jmax+1 DO 20 i=-1imax+1 T(ij)=Ti
95
20 CONTINUE 10 CONTINUE
DO 30 j=Ojmax T(-Ij)=To
30 CONTINUE
DO 40 i=0n3 T(i-I)=To
40 CONTINUE
DO 50 j=Ojmax T(imax+lj)=Ti
50 CONTINUE
DO 60 i=n3+n4+1imax T(i-I)=Ti
60 CONTINUE
cResistors [m-CW]
c interior insulation x direction rl=dx(kinsdy)
c interior insulation y direction r2=dy(kinsdx)
c metalinsulation y direction r3=dy(kmdm+kins(dx-dm))
c metalinsulation x direction r4=dx(kmdm+kins(dy-dm))
c plasticinsulation y direction r5=dy(kpdp+kins(dx-dp))
c plasticinsulation x direction r6s dx(kpdp+kins(dy-dp))
c metal to exterior x direction r7=(heffolaquodx2)-dm)+kins)(heffokinsdy)
c metal to exterior y direction rB=(heffo laquody2)-dm) +kins)(heffokinsdx)
c metal to interior y direction r9=(heffilaquody2)-dm)+kins)(heffikinsdx)
c plastic to interior x direction rl0=(heffilaquodx2)-dp)+kins)(heffikinsdy)
c plastic to interior y direction rll=(heffilaquody2)-dp)+kins)(heffikinsdx)
c metalplastic interface rI2=(2kmdmkpdpdx)(2kmdmkpdp(dy-dp) + (kpdp+km dm)dxdx)
cxxxxxGuass-Siedel Iterationxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx loop=1 iter=1 DO WHILE (loop eq 1)
c Equations for row 0 i=O j=O CALL sseqn(Tr4r7r3rBijimaxjmax)
DO 70 i=ln3 j=O CALL sseqn(Tr4r4r2rBijimaxjmax)
70 CONTINUE
DO 75 i=n3+1n5-1
96
j=O IF (i le n3+n4) THEN
CALL sseqn(Tr4r4r21e20ijimaxjmax) ELSE
CALL sseqn(Tr4r4r2r9ijimaxjmax) ENDIF
75 CONTINUE
i=n5 j-O IF (i le n3+n4) THEN
CALL sseqn(Tr12r4r21e20ijimaxjmax) ELSE
CALL sseqn(Tr12r4r2r9ijimaxjmax) ENDIF
i=n5+1 j=O IF (i le n3+n4) THEN
CALL sseqn(Tr6r12r21e20ijimaxjmax) ELSE
CALL sseqn(Tr6r12r2rllijimaxjmax) ENDIF
DO 80 i=n5+2imax-l j=O IF (i le n3+n4) then
CALL sseqn(Tr6r6r21Oe20ijimaxjmax) ELSE
CALL sseqn(Tr6r6r2rllijimaxjmax) ENDIF
80 CONTINUE
i=imax j=O CALL sseqn(TrlOr6r5rllijimaxjmax)
c Equations for rows 1 thru jmax-l DO 90 j=ljmax-l
i=O CALL sseqn(Tr1r7r3r3ijimaxjmax)
DO 100 i=1imax-1 CALL sseqn(Tr1r1r2r2ijimaxjmax)
100 CONTINUE
i=imax CALL sseqn(Tr10r1r5r5ijimaxjmax)
90 CONTINUE
c Equations for row jmax j=jmax i=O CALL sseqn(Tr1r710e20r3ijimaxjmax)
DO 110 i=1imax-1 j=jmax CALL sseqn(Tr1r110e20r2ijimaxjmax)
110 CONTINUE
i=imax j=jmax CALL sseqn(Tr10r11Oe20r2ijimaxjmax)
97
c c c
Compute the difference in heat flux crossing the outer boundary and crossing the inner boundaryr ideally the difference should be zero
CALL balance(TToTidxdyn3n4imaxjmaxQdifQpdif c QinlQin2r7r9r8rlOrllb)
c Update loop variables iter-iter+l
c Convergence criterium IF (Qpdif le 20) then
loop-O ENDIF IF (iter eq 10000) THEN loop=O write(lO) Solution did not converge
ENDIF
END DO cxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
cHeat Transfer Calculations
c Compute 10 heat flux through wall CALL oneD (ToTiheffoheffikmkinskpdmdpslqlD)
c Compute the flux thru wall at each node on the c outside and inside walls [Wm2) Also the flux c in the x-direction across the center line of the c section
cl-int(nl2) fluxcen(0)=(1(r4dy))(T(cl0)-T(cl+l0)) fluxo(0)=(1(r7dy))(To-T(00)) fluxi(O)=(l(rlOdy))(T(imaxO)-Ti) DO 112 j=ljmax
fluxcen(j)=(l(rldy))(T(clj)-T(cl+lj)) fluxo(j)=(1(r7dy))(To-T(0j)) flumiddotxi (j) =(1 (rlOdy)) (T (imax j)-Ti)
112 CONTINUE
c Determine the percent of steady-state 10 losses DO 113 j=Ojmax
pfluxcen(j)=(fluxcen(j)qlD) 100 pfluxo(j)=(fluxo(j)qlD)lOO pfluxi(j)=(fluxi(j)qlD)lOO
113 CONTINUE
c Determine where the heat transfer becomes 10 c based on a criticle percentage
flagl=O DO 114 j=O jmax
a=abs(pfluxcen(j)-lOOO) IF (j ne jmax) THEN
IF (a le oneDtol) THEN jstar=j
ENDIF ELSE
IF (a le oneDtol) THEN jstar=j
ELSE flagl=l
ENDIF ENDIF
98
114 CONTINUE
c Determine the edge loss by subtracting the 10 heat c transfer from the heat transfer in the 20 region c across the centerline
flag2=0 IF (flagl eq 0) THEN
q2D=00 DO 115 j=O jstar
q2D-q2D+fluxcen(j) 115 CONTINUE
qedgel=q2D-qlD ELSE
flag2=1 ENDIF
c 10 heat flux along metal skin under the seal into c the cabinet [Wm2J Fluxes for all metal nodes are c computed as well as an average flux The flux from c node (n3+l0) to node (n3+20) is given as qlDm(l) c and so on Assume the temperature of the metal skin c is the temperature of the node at that location
suml=OO sum2=00 DO 119 i=n3+1n3+n4-l
Qm(i)=laquokmdmb)dx)(T(i0)-T(i+10raquo qfluxm(i)=(kmdx)(T(iO)-T(i+lOraquo suml=suml+Qm(i) sum2=sum2+qfluxm(i)
119 CONTINUE pmaxdif=laquoQm(n3+n4-l)-Qm(n3+1raquoQm(n3+lraquo100 qedge2-qfluxm(cl)
cOutput
c Output nodal temperatures to separate file DO 120 j=Ojmax
write(ll) (T(ij)i=Oimax) 120 CONTINUE
c Output flux info to a different file write(10) INPUT PARAMETERS write(lO) write (10 ) Section Dimensions (mm) write(lO) Width sl1000 write (10 ) Length s21000 write(10) Depth blOOO write(10) Steel skin thickness dmlOOO write(lO) Plastic skin thickness dplOOO write(lO) write(10) Mesh Geometry write(10) dx dxlOOO write(lO) dy dylOOO write(lO) Number nodes in x-direction n1 write(lO) Number nodes in y-direction n2 write(lO) Number of steel skin nodes write(lO) (including corner 00) n5+l write(10) Steel nodes under the seal n3+1 ton3+n4 write(10) write(lO) Steel skin conductivity (Wm K) km write(lO) Foam insulation conductivity (Wm K) kins write(lO) Plastic skin conductivity (Wm K) kp write(lO) Outside h (Wm2 K) heffo write(lO) Inside h (Wm2 K) heffi
99
write(10) Outside Temp (C) To write(10) Inside Temp (C) Ti write(10) write (10 ) write(10) write(10) OUPUT PARAMETERS write (10 ) write(10) Number of iterations iter write(10) write(10) Heat Transfer for the Section write(10) OVerall Heat Transfer (W) Qin1 write(10) 10 Heat Flux Thru Wall (Wm2) q1D write (10 ) write(10) Heat Transfer Along Metal Skin Under Seal write(10) node to node qm[Wm2J Qm[WJ DO 135 i=n3+1n3+n4-1
write(10) i i+1 qfluxm(i) Qm(i) 135 CONTINUE
write (10 ) Maximum difference () abs (pmaxdif) write(10) IF (flag2 eq 1) THEN
write(10) The mesh does not extend far enough write(10) in the y-direction to reach 10 heat write(10) transfer for the specified tolerance write(10) ofoneDtol
ELSE write (10 ) Edge loss computed from qe=q2D-q1D qedge1 write (10 ) write(10) Edge loss computed directly from write(10) steel skin ~T at centerline qedge2
ENDIF write (10 ) write (10 ) write(10) Heat fluxes in thru the section write(10) along the centerline [Wm2J write (10 ) write(10) j flux 10 DO 136 j=Ojmax
write(10) j fluxcen(j) pfluxcen(j) 136 CONTINUE
PAUSE STOP END
C
SUBROUTINE sseqn (Trplusirminusirplusjrminusj i jimax jmax)
c This subroutine computes the temperature at node (ij) c given the temperatures of the surrounding nodes and c the resistances leading to these nodes
INTEGER ijimaxjmax REAL T(-1101-1101)rplusirminusirplusjrminusj REAL c1c2c3c4c5
c1=1rplusi c2=1rminusi c3=1rplusj c4=1rminusj c5=c1+c2+c3+c4
T(ij)=(1c5)(c1T(i+1j)+c2T(i-1j)+c3T(ij+1)+c4T(ij-1raquo
100
RETURN END
C
SUBROUTINE balance(TToTidxdyn3n4imaxjmaxQdifQpdif c Qin1Qin2r7r8r9r10r11b)
c This subroutine computes the steady-state heat balance c for the cross-section
INTEGER imaxjmaxijn3n4 REAL T(-1101-1101)TlToQin1Qin2dydx REAL r7r8r9r10r11b
c Compute the heat entering Qin1 [Wj Qin1=00 DO 10 jOjmax
Qin1=Qin1+(b(r7))(To-T(0j)) 10 CONTINUE
DO 20 i=0n3 Qin1=Qin1+(b(r8))(To-T(i0))
20 CONTINUE
c Compute the heat leaving Qin2 [Wj Qin2=00 DO 30 j=Ojmax
Qin2=Qin2+(b(r10))(T(imaxj)-Ti) 30 CONTINUE
DO 40 i=n3+n4+1imax IF (i le nS) then
Qin2=Qin2+(b(r9))(T(i0)-Ti) ELSE
Qin2=Qin2+(b(r11))(T(i0)-Ti) ENDIF
40 CONTINUE
c Compute the absolute difference in heat fluxes [Wj Qdif=abs(Qin2-Qin1)
c Compute the percent difference in the heat transfers [Wj Qpdif=(QdifQin1) 100
RETURN END
C
SUBROUTINE oneD (ToTiheffoheffikmkinskpdmdpslqlD)
c This subroutine compute the one-dimensional c heat flux through the section wall
INTEGER i REAL ToTiheffoheffikmkinskpdmdpsl REAL q1DReqdins
dins=sl-dm~dp
Req=(lheffo) + (dmkm) + (dinskins) +(dpkp)+(lheffi) q1D=(To-Ti)Req
RETURN END
101
F3 Fresh Food Wan Simulation Output
INPUT PARAMETERS
Section Dimensions (mm) Width 4500 Length 2000 Depth 1000 Steel skin thickness 6500 Plastic skin thickness 2500
Mesh Geometry dx 2250 dy 2500 Number nodes in x-direction 20 Number nodes in y-direction 80 Number of steel skin nodes (including corner 00) 11 Steel nodes under the seal 2 to 10
Steel skin conductivity (Wm K) 5400 Foam insulation conductivity (Wm K) 21000E-02 Plastic skin conductivity (Wm K) 1500 Outside h (Wm2 K) 6810 Inside h (Wm2 K) 6100 Outside Temp (C) 2100 Inside Temp (C) 4000
OUPUT PARAMETERS
Number of iterations 5318
10 Heat Flux Thru Wall (Wm2) 9132
Heat Transfer Along Metal Skin Under Seal node to node qm[Wm2] Qm[W]
2 3 1619 1092 3 4 1612 1081 4 5 1660 1019 5 6 1645 1010 6 1 1626 1051 1 8 1601 1041 8 9 1569 1020 9 10 1521 9922
Maximum difference () 9101
Edge loss computed directly from steel skin 1T at centerline 1645
Heat fluxes in thru the section along the centerline [Wm2]
j flux 10 0 4284 4691 1 2246 2459 2 3513 3841 3 4554 4981 4 5311 5881 5 6001 6512 6 6488 1104 1 6868 1520
102
10
20
30
40
50
60
70
8 7169 7850 9 7412 8117
7612 8335 11 7778 8517 12 7918 8670 13 8037 8800 14 8139 8912 15 8227 9008 16 8303 9092 17 8369 9164 18 8428 9228 19 8479 9285
8525 9334 21 8565 9379 22 8601 9418 23 8634 9454 24 8663 9486 25 8690 9515 26 8714 9542 27 8736 9566 28 8756 9588 29 8775 9609
8793 9628 31 8809 9645 32 8824 9662 33 8838 9677 34 8851 9692 35 8863 9705 36 8875 9718 37 8886 9730 38 8896 9742 39 8906 9752
8916 9763 41 8925 9772 42 8933 9782 43 8941 9791 44 8949 9799 45 8956 9807 46 8963 9815 47 8970 9822 48 8976 9829 49 8982 9836
8988 9842 51 8994 9848 52 8999 9854 53 9004 9859 54 9009 9864 55 9013 9869 56 9017 9874 57 9021 9878 58 9025 9883 59 9029 9887
9032 9890 61 9036 9894 62 9039 9897 63 9042 9901 64 9044 9903 65 9047 9906 66 9049 9909 67 9051 9911 68 9053 9913 69 9055 9915
9057 9917 71 9058 9919
103
72 9059 9920 73 9061 9921 74 9062 9922 75 9062 9923 76 9063 9924 77 9063 9924 78 9064 9925 79 9064 9925
j local Qwall [Wl
-1 3215 0 -45410E-02 1 -50708E-02 2 -40940E-02 3 -33836E-02 4 -27620E-02 5 -23180E-02 6 -1 9628E-02 7 -1 6076E-02 8 -1 4300E-02 9 -12524E-02 10 -10748E-02 11 -98601E-03 12 -89722E-03 13 -80842E-03 14 -71962E-03 15 -63081E-03 16 -63082E-03 17 -54202E-03 18 -54202E-03 19 -45322E-03 20 -45322E-03 21 -45322E-03 22 -45321E-03 23 -36442E-03 24 -36442E-03 25 -36442E-03 26 -27562E-03 27 -27561E-03 28 -27561E-03 29 -27561E-03 30 -27561E-03 31 -18682E-03 32 -18682E-03 33 -27561E-03 34 -18682E-03 35 -18682E-03 36 -18681E-03 37 -18682E-03 38 -98018E-04 39 -98018E-04 40 -98018E-04 41 -98018E-04 42 -98018E-04 43 -98018E-04 44 -98018E-04 45 -98018E-04 46 -98018E-04 47 -18682E-03 48 -98018E-04 49 -98018E-04 50 -98018E-04 51 -98018E-04 52 -98018E-04
104
53 -98018E-04 54 -92160E-05 55 -98018E-04 56 -98018E-04 57 -98018E-04 58 -98018E-04 59 -98018E-04 60 -92160E-05 61 -98018E-04 62 -92160E-05 63 -98018E-04 64 -98018E-04 65 -92160E-05 66 -98018E-04 67 -98018E-04 68 -92245E-05 69 -92245E-05 70 -98018E-04 71 -98018E-04 72 -98018E-04 73 -92160E-05 74 -92160E-05 75 -92160E-05 76 -92160E-05 77 -92160E-05 78 -92160E-05 79 -92160E-05
Qwallff [Wm21 = 1442 Qwallff [WI = 2775
Fresh Food Nodal Temperatures
x(mm) v(mm) 1125 3375 5625 7875 10125 12375 14625 16875 19125 21375
125 1761 1755 1748 1741 1734 1727 172 1713 1706 17 375 1768 1753 1738 1723 1707 169 1671 165 1624 1589 625 1775 1752 173 1706 1682 1656 1626 1593 1552 15 875 1781 1751 1722 1691 1659 1625 1587 1544 1494 1434
1125 -1787 1751 1715 1678 1639 1598 1553 1504 1448 1384 1375 1792 1751 1709 1667 1622 1576 1526 1471 1412 1346 1625 1798 1752 1705 1658 1609 1557 1503 1446 1384 ll17 1875 1803 1753 1702 165 1597 1543 1485 1425 1362 1294 2125 1808 1754 17 1645 1589 1531 1471 1409 1344 1276 2375 1813 1756 1699 1641 1582 1522 146 1396 133 1262 2625 1817 1758 1698 1638 1577 1515 1451 1386 132 1251 2875 1822 176 1698 1636 1573 151 1445 1379 1311 1242 3125 1826 1762 1699 1635 1571 1506 144 1373 1304 1235 3375 183 1765 17 1635 1569 1503 1436 1368 1299 1229 3625 1834 1768 1701 1635 1568 1501 1433 1364 1295 1225 3875 1837 177 1703 1635 1568 15 1431 1362 1292 1222 4125 1841 1773 1705 1636 1568 1499 143 136 129 1219 4375 1845 1776 1707 1638 1568 1499 1429 1359 1289 1218 4625 1848 1778 1709 1639 1569 1499 1429 1358 1288 1216 4875 1851 1781 1711 164 157 15 1429 1358 1287 1216 5125 1854 1784 1713 1642 1571 15 1429 1358 1287 1215 5375 1857 1786 1715 1644 1573 1501 143 1358 1287 1215 5625 186 1789 1717 1646 1574 1502 1431 1359 1287 1215
105
5875 1863 1791 1719 1647 1576 1504 1432 136 1288 1215 6125 1866 1794 1721 1649 1577 1505 1433 136 1288 1216 6375 1868 1796 1723 1651 1579 1506 1434 1361 1289 1216 6625 1871 1798 1725 1653 158 1508 1435 1362 129 1217 6875 1873 18 1727 1655 1582 1509 1436 1363 1291 1218 7125 1876 1803 1729 1656 1583 151 1437 1364 1291 1218 7375 1878 1805 1731 1658 1585 1512 1439 1366 1292 1219 7625 188 1807 1733 166 1587 1513 144 1367 1293 122 7875 1882 1809 1735 1661 1588 1515 1441 1368 1294 1221 8125 1884 181 1737 1663 159 1516 1442 1369 1295 1222 8375 1886 1812 1738 1665 1591 1517 1444 137 1296 1223 8625 1888 1814 174 1666 1592 1519 1445 1371 1297 1224 8875 189 1816 1742 1668 1594 152 1446 1372 1298 1225 9125 1892 1817 1743 1669 1595 1521 1447 1373 1299 1225 9375 1893 1819 1745 1671 1596 1522 1448 1374 13 1226 9625 1895 182 1746 1672 1598 1524 1449 1375 1301 1227 9875 1896 1822 1748 1673 1599 1525 145 1376 1302 1228 10125 1898 1823 1749 1674 16 1526 1451 1377 1303 1229 10375 1899 1825 175 1676 1601 1527 1452 1378 1304 123 10625 1901 1826 1751 1677 1602 1528 1453 1379 1305 123 10875 1902 1827 1753 1678 1603 1529 1454 138 1305 1231 11125 1903 1828 1754 1679 1604 153 1455 1381 1306 1232 11375 1904 183 1755 168 1605 1531 1456 1381 1307 1232 11625 1906 1831 1756 1681 1606 1532 1457 1382 1308 1233 11875 1907 1832 1757 1682 1607 1532 1458 1383 1308 1234 12125 1908 1833 1758 1683 1608 1533 1458 1384 1309 1234 12375 1909 1834 1759 1684 1609 1534 1459 1384 131 1235 12625 191 1835 176 1685 161 1535 146 1385 131 1235 12875 1911 1836 1761 1686 1611 1536 1461 1386 1311 1236 13125 1912 1837 1761 1686 1611 1536 1461 1386 1311 1236 13375 1913 1837 1762 1687 1612 1537 1462 1387 1312 1237 13625 1913 1838 1763 1688 1613 1538 1462 1387 1312 1237 13875 1914 1839 1764 1688 1613 1538 1463 1388 1313 1238 14125 1915 184 1764 1689 1614 1539 1464 1388 1313 1238 14375 1916 184 1765 169 1614 1539 1464 1389 1314 1239 14625 1916 1841 1766 169 1615 154 1465 1389 1314 1239 14875 1917 1842 1766 1691 1616 154 1465 139 1315 1239 15125 1918 1842 1767 1691 1616 1541 1465 139 1315 124 15375 1918 1843 1767 1692 1616 1541 1466 1391 1315 124 15625 1919 1843 1768 1692 1617 1542 1466 1391 1316 124 15875 1919 1844 1768 1693 1617 1542 1467 1391 1316 1241 16125 192 1844 1769 1693 1618 1542 1467 1392 1316 1241 16375 192 1844 1769 1694 1618 1543 1467 1392 1317 1241 16625 192 1845 1769 1694 1618 1543 1468 1392 1317 1241 16875 1921 1845 177 1694 1619 1543 1468 1392 1317 1242 17125 1921 1846 177 1694 1619 1544 1468 1393 1317 1242 17375 1921 1846 177 1695 1619 1544 1468 1393 1317 1242 17625 1922 1846 1771 1695 1619 1544 1469 1393 1318 1242 17875 1922 1846 1771 1695 162 1544 1469 1393 1318 1242 18125 1922 1847 1771 1695 162 1544 1469 1393 1318 1243 18375 1922 1847 1771 1696 162 1545 1469 1394 1318 1243 18625 1923 1847 1771 1696 162 1545 1469 1394 1318 1243 18875 1923 1847 1771 1696 162 1545 1469 1394 1318 1243 19125 1923 1847 1772 1696 162 1545 1469 1394 1318 1243 19375 1923 1847 1772 1696 162 1545 1469 1394 1318 1243 19625 1923 1847 1772 1696 1621 1545 1469 1394 1318 1243 19875 1923 1847 1772 1696 1621 1545 1469 1394 1318 1243
106
x(mm) y(mm) 23625 25875 28125 30375 32625 34875 37125 39375 41625 43875
125 1694 1662 1287 1033 8577 7336 6444 5795 5324 4995 375 1536 144 125 1068 9163 7946 6974 6189 5532 4944 625 1431 1334 1203 1066 9379 8252 7275 6423 5657 4935 875 136 127 1164 1051 9408 8374 7423 6548 573 4941
1125 131 1226 1132 1034 9353 8394 7477 6605 5766 4948 1375 1273 1193 1107 1017 9262 836 7478 6618 5779 4952 1625 1245 1168 1086 1002 9162 8302 7449 6607 5776 4951 1875 1223 1148 1069 9886 9064 8236 7408 6583 5764 4948 2125 1205 1132 1055 977 8974 8169 7362 6554 5747 4941 2375 1191 1119 1044 9671 8893 8107 7316 6522 5728 4933 2625 118 1108 1034 9588 8824 8051 7273 6492 5709 4925 2875 1172 11 1026 9518 8764 8002 7235 6464 5691 4916 3125 1164 1093 102 946 8713 796 7201 6439 5674 4908 3375 1159 1087 1015 9412 8671 7924 7172 6417 566 49 3625 1154 1083 101 9373 8636 7894 7148 6399 5647 4894 3875 1151 1079 1007 9341 8608 7869 7128 6383 5636 4888 4125 1148 1077 1004 9316 8585 7849 7111 637 5627 4883 4375 1146 1074 1002 9296 8566 7833 7097 6359 5619 4879 4625 1145 1073 1001 9281 8552 7821 7087 6351 5613 4875 4875 1144 1072 9995 927 8541 7811 7078 6344 5609 4872 5125 1143 1071 9987 9261 8533 7803 7072 6339 5605 487 5375 1143 1071 9982 9256 8528 7798 7067 6335 5602 4868 5625 1143 107 9979 9253 8524 7795 7064 6332 56 4867 5875 1143 107 9978 9251 8522 7793 7062 6331 5599 4866 6125 1143 1071 9979 9251 8522 7792 7061 633 5598 4866 6375 1144 1071 9981 9252 8523 7792 7061 633 5598 4865 6625 1144 1071 9984 9255 8524 7793 7062 633 5598 4865 6875 1145 1072 9988 9258 8526 7795 7063 6331 5598 4865 7125 1145 1072 9993 9261 8529 7797 7065 6332 5599 4866 7375 1146 1073 9998 9265 8533 78 7067 6333 56 4866 7625 1147 1074 10 927 8536 7803 7069 6335 5601 4867 7875 1148 1074 1001 9275 854 7806 7072 6337 5602 4867 8125 1148 1075 1001 928 8545 7809 7074 6339 5603 4868 8375 1149 1076 1002 9285 8549 7813 7077 6341 5605 4869 8625 115 1076 1003 929 8553 7817 708 6343 5606 4869 8875 1151 1077 1003 9295 8558 782 7083 6345 5608 487 9125 1152 1078 1004 93 8562 7824 7086 6347 5609 4871 9375 1152 1078 1004 9306 8567 7828 7089 635 5611 4872 9625 1153 1079 1005 9311 8571 7831 7092 6352 5612 4873 9875 1154 108 1006 9316 8575 7835 7094 6354 5614 4873 10125 1155 108 1006 9321 858 7838 7097 6356 5615 4874 10375 1155 1081 1007 9326 8584 7842 71 6358 5617 4875 10625 1156 1082 1007 933 8588 7845 7103 636 5618 4876 10875 1157 1082 1008 9335 8592 7848 7105 6362 5619 4876 11125 1157 1083 1008 9339 8596 7852 7108 6364 5621 4877 11375 1158 1083 1009 9344 8599 7855 711 6366 5622 4878 11625 1158 1084 1009 9348 8603 7858 7113 6368 5623 4879 11875 1159 1084 101 9352 8606 7861 7115 637 5625 4middot879 12125 116 1085 101 9356 861 7864 7117 6372 5626 488 12375 116 1085 1011 936 8613 7866 712 6373 5627 488 12625 1161 1086 1011 9363 8616 7869 7122 6375 5628 4881 12875 1161 1086 1011 9367 8619 7871 7124 6376 5629 4882 13125 1162 1087 1012 937 8622 7874 7126 6378 563 4882 13375 1162 1087 1012 9373 8625 7876 7128 6379 5631 4883 13625 1162 1087 1013 9376 8627 7878 7129 6381 5632 4883
107
13875 1163 1088 1013 9379 863 788 7131 6382 5633 4884 14125 1163 1088 1013 9382 8632 7882 7133 6383 5634 4884 14375 1164 1089 1013 9384 8634 7884 7134 6384 5634 4885 14625 1164 1089 1014 9387 8636 7886 7136 6385 5635 4885 14875 1164 1089 1014 9389 8638 7888 7137 6386 5636 4885 15125 1165 1089 1014 9392 864 7889 7138 6387 5637 4886 15375 1165 109 1015 9394 8642 7891 714 6388 5637 4886 15625 1165 109 1015 9396 8644 7892 7141 6389 5638 4886 15875 1165 109 1015 9398 8646 7894 7142 639 5638 4887 16125 1166 109 1015 9399 8647 7895 7143 6391 5639 4887 16375 1166 1091 1015 9401 8649 7896 7144 6392 5639 4887 16625 1166 1091 1016 9403 865 7897 7145 6392 564 4888 16875 1166 1091 1016 9404 8651 7898 7146 6393 564 4888 17125 1167 1091 1016 9405 8652 7899 7146 6394 5641 4888 17375 1167 1091 1016 9406 8653 79 7147 6394 5641 4888 17625 1167 1091 1016 9407 8654 7901 7148 6395 5641 4888 17875 1167 1092 1016 9408 8655 7902 7148 6395 5642 4889 18125 1167 1092 1016 9409 8656 7902 7149 6395 5642 4889 18375 1167 1092 1016 941 8656 7903 7149 6396 5642 4889 18625 1167 1092 1016 9411 8657 7903 715 6396 5642 4889 18875 1167 1092 1017 9411 8657 7904 715 6396 5643 4889 19125 1167 1092 1017 9412 8658 7904 715 6396 5643 4889 19375 1167 1092 1017 9412 8658 7904 715 6397 5643 4889 19625 1167 1092 1017 9412 8658 7904 715 6397 5643 4889 19875 1168 1092 1017 9412 8658 7904 715 6397 5643 4889
F4 Freezer Wall Simulation Output
INPUT PARAMETERS
Section Dimensions (mm) Width 5600 Length 2000 Depth 1000 Steel skin thickness 6500 Plastic skin thickness 2500
Mesh Geometry dx 2800 dy 2500 Number nodes in x-direction 20 Number nodes in y-direction 80 Number of steel skin nodes (including corner 00) 9 Steel nodes under the seal 2 to 8
Steel skin conductivity (Wm K) 5400 Foam insulation conductivity (Wm K) 27000E-02 Plastic skin conductivity (Wm K) 1500 Outside h (Wm2 K) 6870 Inside h (Wm2 K) 6410 Outside Temp (C) 2100 Inside Temp (C) -1000
OUPUT PARAMETERS
108
Number of iterations 5409
Heat Transfer for the Section OVerall Heat Transfer (WI 4518 10 Heat Flux Thru Wall (Wm21 1362
Heat Transfer Along Metal Skin Under Seal node to node
2 3 3 4 4 5 5 6 6 7 7 8
Maximum difference
qm[Wm2) Om(W) 3026 1967 3008 1955 2981 1938 2944 1914 2892 1880 2820 1833
(1 6799
Edge loss computed from qe=q20-q1D 1760
Edge loss compusteel skin AT
ted directly from at centerline 2981
Heat fluxes in thru the section along the centerline [Wm2)
j flux UO 0 7762 5698 1 3711 2724 2 5678 41 68 3 7275 5341 4 8508 6246 5 9437 6927 6 1013 7438 7 1066 7823 8 1106 8117 9 1137 8347 10 1162 8529 11 1182 8678 12 1199 8801 13 1213 8904 14 1225 8992 15 1235 9068 16 1244 9135 17 1252 9193 18 1259 9245 19 1266 9291 20 1271 9333 21 1276 9370 22 1281 9405 23 1285 9436 24 1289 9464 25 1293 9491 26 1296 9515 27 1299 9538 28 1302 9559 29 1305 9578 30 1307 9596 31 1310 9614 32 1312 9630 33 1314 9645 34 1316 9659 35 1318 9673 36 1319 9685 37 1321 9697
109
38 1323 9709 39 1324 9720 40 1325 9730 41 1327 9740 42 1328 9749 43 1329 9758 44 1330 9767 45 1332 9775 46 1333 9783 47 1334 97bull 90 48 1335 9797 49 1336 9804 50 1336 9810 51 1337 9816 52 1338 9822 53 1339 9828 54 1340 9833 55 1340 9838 56 1341 9843 57 1341 9847 58 1342 9852 59 1343 9856 60 1343 9859 61 1344 9863 62 1344 9866 63 1344 9870 64 1345 9873 65 1345 9875 66 1346 9878 67 1346 9880 68 1346 9882 69 1347 9884 70 1347 9886 71 1347 9888
72 1347 9889 73 1347 9891 74 1347 9892 75 1348 9893 76 1348 9893 77 1348 9894 78 1348 9894 79 1348 9894
j local Qwall [WI
-1 3067 0 -36774E-02 1 -40214E-02 2 -32314E-02 3 -25994E-02 4 -20859E-02 5 -16909E-02 6 -14144E-02 7 -12169E-02 8 -10589E-02 9 -90092E-03 10 -78242E-03 11 -70342E-03 12 -66392E-03 13 -58492E-03 14 -54542E-03 15 -50592E-03 16 -46642E-03 17 -42692E-03 18 -42692E-03
110
19 -38742E-03 20 -34792E-03 21 -30842E-03 22 -30842E-03 23 -30842E-03 24 -26892E-03 25 -26892E-03 26 -22942E-03 27 -22942E-03 28 -22942E-03 29 -22942E-03 30 -18992E-03 31 -1 8992E-03 32 -18992E-03 33 -18992E-03 34 -1 8992E-03 35 -1 5042E-03 36 -1 8992E-03 37 -15042E-03 38 -1 5042E-03 39 -11092E-03 40 -11092E-03 41 -11092E-03 42 -11092E-03 43 -11092E-03 44 -11092E-03 45 -11092E-03 46 -11092E-03 47 -71417E-04 48 -11092E-03 49 -71421E-04 50 -11092E-03 51 -71417E-04 52 -11092E-03 53 -71417E-04 54 -71421E-04 55 -71421E-04 56 -71417E-04 57 -31916E-04 58 -31920E-04 59 -31916E-04 60 -31916E-04 61 -71417E-04 62 -11421E-04 63 -71421E-04 64 -31920E-04 65 -31920E-04 66 -71417E-04 67 -31916E-04 68 -71417E-04 69 -31920E-04 70 -71421E-04 71 -31920E-04 72 -31920E-04 73 -71417E-04 74 -31916E-04 75 -31916E-04 76 -31916E-04 77 -31916E-04 78 -71417E-04 79 -71417E-04
Qwallfz [Wm2J = 2895 Qwallfz [WJ = 2721
111
Freezer Wan Nodal Temperatures
x(mm) y1mm 14 42 70 98 126 154 182 210 238 266
125 1507 1492 1477 1461 1445 143 1415 14 1385 1338 375 1519 1489 1458 1426 1392 1353 1307 1247 1154 972 625 1531 1486 1441 1393 1341 1282 1212 1121 9925 7989 875 1542 1484 1425 1363 1296 1221 1132 1023 8837 7014
1125 1553 1483 1412 1338 1258 117 1069 9508 809 6396 1375 1563 1483 1401 1317 1227 1129 102 8969 7563 5974 1625 1572 1483 1393 13 1202 1097 9824 8568 7184 5673 1875 1582 1485 1387 1287 1182 1072 9537 8269 6906 5452 2125 1591 1488 1384 1277 1167 1053 9321 8046 67 5288 2375 1599 1491 1382 1271 1157 1039 916 7881 6547 5164 2625 1608 1495 1381 1266 1149 1028 9041 7758 6433 5071 2875 1616 1499 1382 1264 1144 1021 8955 7668 6349 5002 3125 1623 1504 1384 1263 114 1016 8895 7604 6288 495 3375 1631 1509 1386 1263 1139 1013 8854 7559 6245 4913 3625 1638 1514 1389 1264 1138 1011 8829 753 6216 4888 3875 1645 1519 1393 1266 1139 1011 8816 7513 6198 4872 4125 1652 1524 1396 1269 114 1011 8813 7505 6188 4863 4375 1658 1529 14 1271 1142 1012 8817 7505 6185 486 4625 1664 1534 1405 1275 1144 1014 8826 751 6188 4861 4875 167 1539 1409 1278 1147 1016 884 752 6195 4867 5125 1676 1544 1413 1281 115 1018 8858 7533 6206 4875 5375 1682 1549 1417 1285 1153 102 8877 755 6219 4886 5625 1687 1554 1421 1289 1156 1023 8899 7568 6235 4899 5875 1692 1559 1425 1292 1159 1026 8923 7588 6252 4914 6125 1698 1563 143 1296 1162 1028 8947 7609 627 493 6375 1702 1568 1434 1299 1165 1031 8972 763 6289 4946 6625 1707 1572 1438 1303 1169 1034 8997 7653 6308 4964 6875 1712 1576 1441 1306 1172 1037 9022 7675 6329 4982 7125 1716 158 1445 131 1175 104 9048 7698 6349 5 7375 172 1584 1449 1313 1178 1043 9073 7721 6369 5018 7625 1724 1588 1452 1317 1181 1045 9098 7744 639 5036 7875 1728 1592 1456 132 1184 1048 9123 7766 641 5054 8125 1732 1595 1459 1323 1187 1051 9147 7788 643 5072 8375 1736 1599 1462 1326 1189 1053 917 781 645 509 8625 1739 1602 1465 1329 1192 1056 9194 7831 6469 5108 8875 1743 1605 1468 1332 1195 1058 9216 7852 6488 5125 9125 1746 1609 1471 1334 1197 1061 9238 7872 6507 5142 9375 1749 1612 1474 1337 12 1063 926 7892 6525 5158 9625 1752 1615 1477 134 1202 1065 9281 7911 6542 5174 9875 1755 1617 148 1342 1205 1067 9301 793 656 519 10125 1758 162 1482 1344 1207 1069 9321 7948 6576 5205 10375 1761 1623 1485 1347 1209 1071 934 7966 6593 522 10625 1763 1625 1487 1349 1211 1073 9358 7983 6608 5234 10875 1766 1627 1489 1351 1213 1075 9376 7999 6623 5248 11125 1768 163 1491 1353 1215 1077 9393 8015 6638 5262 11375 1771 1632 1494 1355 1217 1079 941 8031 6652 5275 11625 1773 1634 1496 1357 1219 1081 9426 8045 6666 5287 11875 1775 1636 1498 1359 1221 1082 9441 806 6679 53 12125 1777 1638 1499 1361 1222 1084 9456 8073 6692 5311 12375 1779 164 1501 1362 1224 1085 947 8087 6704 5322 12625 1781 1642 1503 1364 1225 1087 9483 8099 6716 5333 12875 1783 1644 1505 1366 1227 1088 9496 8111 6727 5344
112
13125 1784 1645 1506 1367 1228 109 9509 8123 6738 5353 13375 1786 1647 1508 1369 123 1091 9521 8134 6748 5363 13625 1788 1648 1509 137 1231 1092 9532 8145 6758 5372 13875 1789 165 151 1371 1232 1093 9543 8155 6768 5381 14125 1791 1651 1512 1373 1233 1094 9554 8165 6777 5389 14375 1792 1652 1513 1374 1235 1095 9564 8174 6785 5397 14625 1793 1654 1514 1375 1236 1096 9573 8183 6793 5404 14875 1794 1655 1515 1376 1237 1097 9582 8191 6801 5412 15125 1796 1656 1516 1377 1238 1098 959 8199 6808 5418 15375 1797 1657 1517 1378 1238 1099 9598 8206 6815 5425 15625 1798 1658 1518 1379 1239 11 9606 8213 6822 5431 15875 1799 1659 1519 138 124 1101 9613 822 6828 5436 16125 18 166 152 138 1241 1101 9619 8226 6834 5442 16375 18 1661 1521 1381 1242 1102 9626 8232 6839 5446 16625 1801 1661 1521 1382 1242 1103 9631 8237 6844 5451 16875 1802 1662 1522 1382 1243 1103 9637 8242 6848 5455 17125 1803 1663 1523 1383 1243 1104 9642 8247 6853 5459 17375 1803 1663 1523 1384 1244 1104 9646 8251 6857 5463 17625 1804 1664 1524 1384 1244 1105 965 8255 686 5466 17875 1804 1664 1524 1384 1245 1105 9654 8258 6863 5469 18125 1805 1665 1525 1385 1245 1105 9657 8261 6866 5471 18375 1805 1665 1525 1385 1245 1106 966 8264 6869 5474 18625 1805 1665 1525 1385 1246 1106 9662 8266 6871 5476 18875 1806 1666 1526 1386 1246 1106 9664 8268 6872 5477 19125 1806 1666 1526 1386 1246 1106 9666 827 6874 5479 19375 1806 1666 1526 1386 1246 1106 9667 8271 6875 548 19625 1806 1666 1526 1386 1246 1107 9668 8271 6876 548 19875 1806 1666 1526 1386 1246 1107 9668 8272 6876 5481
x(mm) v(mm) 294 322 350 378 406 434 462 490 518 546
125 549 054 -27 -5 -624 -727 -8 -85 -89 -92 375 548 171 -12 -338 -5 -624 -719 -795 -858 -914 625 51 22 -032 -24 -408 -543 -654 -748 -83 -907 875 474 238 0182 -175 -34 -482 -603 -71 -807 -898
1125 445 243 048 -132 -293 -436 -564 -68 -787 -89 1375 423 243 0653 -103 -259 -402 -534 -656 -772 -883 1625 406 24 0752 -084 -236 -378 -511 -638 -759 -877 1875 393 237 0808 -071 -219 -36 -495 -624 -749 -871 2125 382 233 0837 -063 -208 -348 -483 -614 -741 -867 2375 374 23 085 -058 -2 -339 -474 -606 -735 -863 2625 368 227 0855 -055 -195 -332 -467 -6 -731 -86 2875 363 225 0855 -053 -191 -328 -462 -596 -728 -858 3125 36 223 0853 -052 -189 -324 -459 -593 -725 -856 3375 357 221 0851 -051 -187 -322 -457 -59 -723 -855 3625 355 22 0849 -05 -186 -32 -455 -588 -722 -854 3875 354 219 0849 -049 -185 -319 -453 -587 -72 -853 4125 353 219 0849 -049 -184 -318 -452 -586 -72 -853 4375 353 219 0852 -049 -183 -317 -451 -585 -719 -852 4625 353 219 0855 -048 -183 -317 -451 -584 -718 middot852 4875 353 22 0861 -047 -182 -316 -45 -584 -718 -852 5125 354 22 0867 -047 -181 -315 -449 -584 -717 -851 5375 355 221 0875 -046 -181 -315 -449 -583 -717 -851 5625 356 222 0884 -045 -18 -314 -448 -582 -717 -851 5875 358 223 0894 -044 -179 -313 -448 -582 -716 -851 6125 359 225 0904 -043 -178 -313 -447 -582 -716 -851 6375 36 226 0915 -043 -177 -312 -447 -581 -716 -85
113
6625 362 227 0927 -042 -177 -311 -446 -581 -716 -85 6875 363 229 0939 -04 -176 -311 -445 -58 -715 -85 7125 365 23 0951 -039 -175 -31 -445 -58 -715 -85 7375 367 232 0964 -038 -174 -309 -444 -579 -715 -85 7625 368 233 0976 -037 -173 -308 -444 -579 -714 -85 7875 37 234 0989 -036 -172 -308 -443 -578 -714 -849 8125 371 236 1 -035 -171 -307 -442 -578 -714 -849 8375 373 237 101 -034 -17 -306 -442 -578 -713 -849 8625 375 239 103 -033 -169 -305 -441 -577 -713 -849 8875 376 24 104 -032 -168 -305 -441 -577 -713 -849 9125 378 241 105 -031 -168 -304 -44 -576 -712 -849 9375 379 243 106 -03 -167 -303 -439 -576 -712 -848 9625 381 244 107 -029 -166 -302 -439 -575 -712 -848 9875 382 245 109 -028 -165 -302 -438 -575 -712 -848 10125 384 246 11 -027 -164 -301 -438 -574 -711 -848 10375 385 248 111 -026 -163 -3 -437 -574 -711 -848 10625 386 249 112 -025 -163 -3 -437 -574 -711 -848 10875 387 25 113 -024 -162 -299 -436 -573 -711shy -848 11125 389 251 114 -023 -161 -298 -436 -573 -71 -848 11375 39 252 115 -022 -16 -298 -435 -573 -71 -847 11625 391 253 115 -022 -16 -297 -435 -572 -71 -847 11875 392 254 116 -021 -159 -297 -434 -572 -709 -847 12125 393 255 117 -02 -158 -296 -434 -572 -709 -847 12375 394 256 118 -019 -158 -296 -434 -571 -709 -847 12625 395 257 119 -019 -157 -295 -433 -571 -709 -847 12875 396 258 12 -018 -157 -295 -433 -571 -709 -847 13125 397 259 12 -017 -156 -294 -432 -57 -709 -847 13375 398 259 121 -017 -155 -294 -432 -57 -708 -847 13625 399 26 122 -016 -155 -293 -432 -57 -708 -846 13875 399 261 122 -016 -154 -293 -431 -57 -708 -846 14125 4 262 123 -015 -154 -292 -431 -569 -708 -846 14375 401 262 124 -015 -154 -292 -431 -569 -708 -846 14625 402 263 124 -014 -153 -292 -43 -569 -707 -846 14875 402 263 125 -014 -153 -291 -43 -569 -707 -846 15125 403 264 125 -013 -152 -291 -43 -569 -707 -846 15375 403 264 126 -013 -152 -291 -43 -568 -707 -846 15625 404 265 126 -012 -152 -291 -429 -568 -707 -846 15875 405 265 126 -012 -151 -29 -429 -568 -707 -846 16125 405 266 127 -012 -151 -29 -429 -568 -707 -846 16375 405 266 127 -011 -151 -29 -429 -568 -707 -846 16625 406 267 128 -011 -151 -29 -429 -568 -707 -846 16875 406 267 128 -011 -15 -289 -428 -568 -707 -845 17125 407 267 128 -01 -15 -289 -428 -567 -706 -845 17375 407 268 128 -01 -15 -289 -428 -567 -706 -845 17625 407 268 129 -01 -15 -289 -428 -567 -706 -845 17875 407 268 129 -01 -15 -289 -428 -567 -706 -845 18125 408 268 129 -01 -15 -289 -428 -567 -706 -845 18375 408 269 129 -01 -149 -289 -428 -567 -706 -845 18625 408 269 129 -001 -149 -288 -428 -567 -706 -845 18875 408 269 129 -001 -149 -288 -428 -567 -706 -845 19125 408 269 13 -001 -149 -288 -428 -567 -706 -845 19375 409 269 13 -001 -149 -288 -428 -567 -706 -845 19625 409 269 13 -001 -149 -288 -428 -567 -706 -845 19875 409 269 13 -001 -15 -288 -428 -567 -706 -845
114
FS Fresh Food Wan Simulation Output Including Anti-sweat Condenser Tube
INPUT PARAMETERS
Section Dimensions (mm) Hidth 4500 Length 2000 Depth 2960 Steel skin thickness 6500 Plastic skin thickness 2500
Mesh Geometry dx 2250 dy 2500 Number nodes in x-direction 20 Number nodes in y-direction 80 Number of steel skin nodes (including corner 00) 11 Steel nodes under the seal 2 to 10 Tube located at node 6
Steel skin conductivity (Him K) 5400 Foam insulation conductivity (Him K) 27000E-02 Plastic skin conductivity (Him K) 1500 Outside h (Hm2 K) 6870 Inside h (Hm2 K) 6700 Outside Temp (C) 2100 Inside Temp (C) 4000
OUPUT PARAMETERS
Number of iterations 602
10 Heat Flux Thru Hall (Hm2) 9132
Heat Transfer Along Metal Skin Under Seal node to node qm[Hm21 Qm[HI
2 3 -15052E+04 -2896 3 4 -15125E+04 -2910 4 5 -15198E+04 -2924 5 6 -15274E+04 -2939 6 7 3996 7688 7 8 3898 7500 8 9 3790 7292 9 10 3662 7045
Maximum difference () 1243
j qleft [HI qright [HI -1 -2957 7832 0 -92065E-02 -38838E-02 1 -77348E-02 -48044E-02 2 -51596E-02 -30284E-02 3 -32948E-02 -15188E-02 4 -1 9628E-02 -54201E-03 5 -98600E-03 16837E-03 6 -36442E-03 70ll8E-03 7 79586E-04 96757E-03 8 43478E-03 11452E-02 9 70118E-03 12340E-02 10 87877E-03 12340E-02
115
11 87879E-03 13228E-02 12 10564E-02 12340E-02 13 10564E-02 11452E-02 14 96759E-03 11452E-02 15 87877E-03 10564E-02 16 87879E-03 87877E-03 17 78999E-03 87877E-03 18 61238E-03 78999E-03 19 61240E-03 61237E-03 20 52359E-03 52358E-03 21 34598E-03 34598E-03 22 25719E-03 25717E-03 23 16838E-03 16839E-03 24 79586E-04 25 -98018E-04 26 -18681E-03 27 -27561E-03 28 -36442E-03 29 -54202E-03 30 -54202E-03 31 -7 1962E-03 32 -80842E-03 33 -8 9721E-03 34 -98602E-03 35 -10748E-02 36 -11636E-02 37 -12524E-02 38 -1 3412E-02 39 -1 4300E-02 40 -15188E-02 41 -1 5188E-02 42 -1 6076E-02 43 -16964E-02 44 -17852E-02 45 -1 7852E-02 46 -1 8740E-02 47 -19628E-02 48 -19628E-02 49 -19628E-02 50 -20516E-02 51 -21404E-02 52 -22292E-02 53 -22292E-02 54 -23180E-02 55 -23180E-02 56 -23180E-02 57 -24068E-02
79578E-04 -98018E-04 -1 8682E-03 -27561E-03 -45322E-03 -54202E-03 -71962E-03 -71962E-03 -8 9722E-03 -8 9722E-03 -10748E-02 -11636E-02 -12524E-02 -13412E-02 -14300E-02 -1 5188E-02 -16076E-02 -16964E-02 -16964E-02 -17852E-02 -18740E-02 -19628E-02 -20516E-02 -20516E-02 -21404E-02 -22292E-02 -22470E-02 -22381E-02 -22647E-02 -23358E-02 -23447E-02 -23802E-02 -24512E-02 -24690E-02
58 -23979E-02 -25223E-02 59 -24423E-02 60 -24246E-02 61 -24423E-02 62 -24779E-02 63 -25400E-02 64 -25400E-02 65 -25667E-02 66 -26199E-02 67 -26022E-02 68 -26111E-02 69 -26377E-02 70 -26022E-02 71 -26732E-02 72 -26821E-02 73 -26199E-02 74 -26643E-02
-25489E-02 -25755E-02 -25933E-02 -2 6199E-02 -26466E-02 -26643E-02 -26821E-02 -26910E-02 -27087E-02 -27265E-02 -27354E-02 -27443E-02 -27531E-02 -27620E-02 -27620E-02 -27709E-02
116
75 -26377E-02 -27709E-02 76 -26377E-02 -27709E-02 77 -26555E-02 -27709E-02 78 -26910E-02 -27620E-02 79 -26555E-02 -27620E-02
Qleft [ii] -3079 Qright [ii] 6756 Percent entering cabinet 1800
Fresh Food Nodal Temperatures (Condenser Tube)
x(mm) y(mm) 1125 3375 5625 7875 10125 12375 14625 16875 19125 21375
19875 126 1206 1154 1104 1055 1007 9608 9158 872 8294 19625 1259 1205 1153 1103 1054 1006 9602 9152 8715 8289 19375 1259 1205 1153 1102 1053 1006 9598 9149 8711 8285 19125 1259 1205 1153 1102 1053 1006 9596 9147 871 8284 18875 1259 1205 1153 1102 1053 1006 9596 9147 871 8284 18625 1259 1205 1153 1103 1054 1006 9599 915 8712 8286 18375 126 1206 1154 1103 1054 1007 9604 9154 8716 829 18125 1261 1207 1155 1104 1055 1007 9611 9161 8722 8295 17875 1263 1209 1156 1105 1056 1008 962 9169 873 8302 17625 1264 121 1158 1107 1058 101 9632 918 874 8311 17375 1266 1212 116 1109 1059 1011 9646 9193 8752 8322 17125 1269 1215 1162 1111 1061 1013 9663 9209 8766 8335 16875 1272 1217 1164 1113 1063 1015 9682 9226 8783 835 16625 1275 122 1167 1116 1066 1017 9704 9246 8801 8367 16375 1279 1224 117 1119 1069 102 9728 9269 8822 8386 16125 1282 1227 1174 1122 1072 1023 9755 9294 8845 8407 15875 1287 1231 1178 1126 1075 1026 9785 9322 887 843 15625 1292 1236 1182 113 1079 103 9818 9352 8898 8456 15375 1297 1241 1187 1134 1083 1034 9854 9385 8929 8484 15125 1302 1246 1192 1139 1088 1038 9892 9421 8962 8514 14875 1308 1252 1197 1144 1092 1042 9934 946 8998 8547 14625 1315 1258 1203 1149 1097 1047 9979 9502 9037 8583 14375 1322 1265 1209 1155 1103 1052 1003 9547 9078 8621 14125 1329 1272 1216 1162 1109 1058 1008 9595 9123 8662 13875 1337 1279 1223 1168 1115 1064 1014 9647 9171 8706 13625 1346 1287 1231 1176 1122 107 102 9703 9222 8753 13375 1355 1296 1239 1183 1129 1077 1026 9762 9277 8803 13125 1364 1305 1247 1191 1137 1084 1033 9824 9335 8856 12875 1374 1314 1256 12 1145 1092 104 9891 9396 8913 12625 1385 1325 1266 1209 1154 11 1047 9962 9462 8973 12375 1396 1335 1276 1219 1163 1109 1055 1004 9531 9037 12125 1408 1347 1287 1229 1173 1118 1064 1012 9605 9105 11875 1421 1359 1299 124 1183 1127 1073 102 9683 9176 11625 1434 1371 1311 1251 1194 1137 1082 1029 9765 9252 11375 1448 1385 1323 1263 1205 1148 1092 1038 9851 9332 11125 1462 1399 1336 1276 1217 1159 1103 1048 9943 9416 10875 1478 1413 135 1289 1229 1171 1114 1058 1004 9505 10625 1494 1429 1365 1303 1243 1184 1126 1069 1014 9598 10375 1511 1445 138 1318 1257 1197 1138 1081 1025 9696 10125 1528 1462 1397 1333 1271 121 1151 1093 1036 98 9875 1547 1479 1413 1349 1286 1225 1165 1106 1048 9908 9625 1566 1498 1431 1366 1302 124 1179 1119 106 1002
117
9375 1586 1517 145 1384 1319 1256 1194 1133 1073 1014 9125 1607 1537 1469 1402 1336 1272 1209 1147 1087 1027 8875 1629 1558 1489 1421 1355 129 1226 1163 1101 104 8625 1652 158 151 1441 1374 1308 1243 1179 1116 1054 8375 1676 1603 1532 1462 1394 1327 1261 1195 1131 1068 8125 17 1627 1555 1484 1415 1346 1279 1213 1148 1084 7875 1726 1652 1579 1507 1436 1367 1299 1231 1165 11 7625 1753 1678 1604 1531 1459 1389 1319 1251 1183 1116 7375 1781 1704 1629 1556 1483 1411 1341 1271 1202 1134 7125 1809 1732 1656 1581 1508 1435 1363 1292 1222 1152 6875 1839 1761 1684 1608 1533 146 1387 1314 1243 1172 6625 187 1791 1713 1636 156 1485 1411 1337 1264 1192 6375 1903 1823 1744 1666 1589 1512 1437 1362 1287 1214 6125 1936 1855 1775 1696 1618 1541 1464 1387 1312 1236 5875 197 1889 1808 1728 1649 157 1492 1414 1337 126 5625 2006 1923 1842 1761 1681 1601 1522 1443 1364 1285 5375 2043 196 1877 1795 1714 1633 1553 1473 1392 1312 5125 2081 1997 1914 1832 1749 1668 1586 1504 1422 134 4875 212 2036 1952 1869 1786 1704 1621 1538 1454 137 4625 2161 2076 1992 1909 1825 1741 1658 1573 1488 1403 4375 2203 2118 2034 195 1866 1782 1697 1611 1525 1437 4125 2246 2161 2077 1993 1909 1824 1738 1652 1564 1474 3875 229 2206 2123 2039 1955 1869 1783 1695 1606 1515 3625 2336 2253 217 2087 2003 1918 1831 1742 1651 1558 3375 2383 2302 222 2138 2055 197 1882 1793 1701 1606 3125 2432 2353 2273 2192 211 2026 1938 1848 1755 1658 2875 2482 2405 2328 225 217 2086 20 1909 1815 1715 2625 2533 2461 2387 2312 2234 2153 2067 1977 1881 178 2375 2586 2518 2449 2378 2304 2226 2142 2052 1955 1851 2125 264 2579 2516 2451 2381 2306 2225 2136 2039 1933 1875 2696 2642 2587 2529 2466 2396 2319 2232 2134 2026 1625 2753 2709 2664 2614 256 2497 2425 2341 2244 2133 1375 2811 278 2746 2708 2664 2611 2546 2468 2373 226 1125 2871 2854 2835 2811 278 2739 2685 2615 2524 2411 875 2932 2932 293 2923 2909 2885 2846 2787 2706 2595 625 2995 3014 3031 3045 3052 3049 3031 2989 2922 2824 375 3058 3098 3138 3175 3208 3234 3245 3223 3179 3109 125 3124 3185 3247 331 3373 3436 35 3483 3467 3451
x(mm) y(mm) 23625 25875 28125 30375 32625 34875 37125 39375 41625 43875
19875 7877 747 7071 6679 6294 5915 554 5168 4799 4432 19625 7872 7466 7067 6676 6291 5912 5538 5166 4798 4431 19375 7869 7463 7065 6674 6289 591 5536 5165 4797 443 19125 7868 7462 7063 6673 6288 591 5535 5165 4797 443 18875 7868 7462 7063 6673 6288 591 5535 5165 4796 443 18625 787 7463 7065 6674 6289 591 5536 5165 4797 443 18375 7873 7466 7067 6676 6291 5912 5537 5166 4797 443 18125 7878 747 7071 6679 6294 5914 5539 5167 4798 4431 17875 7884 7476 7076 6684 6298 5917 5542 5169 4799 4431 17625 7893 7483 7083 6689 6303 5921 5545 5172 4801 4432 17375 7903 7492 7091 6696 6309 5926 5549 5175 4803 4433 17125 7914 7503 71 6704 6316 5932 5553 5178 4806 4435 16875 7928 7515 7111 6714 6324 5939 5559 5182 4809 4436 16625 7943 7529 7123 6725 6333 5947 5565 5187 4812 4438 16375 796 7544 7137 6737 6343 5955 5572 5192 4815 444 16125 7979 7561 7152 675 6355 5965 558 5198 4819 4442
118
15875 8001 7581 7169 6765 6368 5976 5589 5205 4824 4445 15625 8024 7601 7188 6781 6382 5987 5598 5212 4829 4447 15375 8049 7624 7208 6799 6397 6 5608 522 4834 445 15125 8077 7649 723 6819 6414 6014 562 5229 484 4453 14875 8107 7676 7254 684 6432 603 5632 5238 4847 4457 14625 8139 7705 728 6862 6451 6046 5645 5248 4854 4461 14375 8174 7737 7308 6887 6472 6064 566 5259 4861 4465 14125 8211 777 7338 6913 6495 6083 5675 5271 4869 4469 13875 8251 7806 737 6941 6519 6103 5691 5283 4878 4474 13625 8294 7845 7405 6972 6545 6125 5709 5297 4887 4479 13375 834 7886 7441 7004 6573 6148 5728 5311 4897 4484 13125 8388 793 748 7038 6603 6173 5748 5326 4907 449 12875 844 7977 7522 7075 6634 62 5769 5343 4918 4496 12625 8495 8026 7566 7114 6668 6228 5792 536 493 4502 12375 8553 8079 7613 7155 6703 6258 5816 5378 4943 4509 12125 8615 8135 7663 7199 6741 6289 5842 5398 4956 4517 11875 868 8194 7716 7245 6781 6323 5869 5418 4971 4524 11625 8749 8256 7771 7294 6823 6358 5898 544 4986 4532 11375 8822 8322 783 7346 6868 6396 5928 5463 5002 4541 11125 8899 8392 7892 7401 6915 6435 596 5488 5018 455 10875 898 8465 7958 7458 6965 6477 5994 5514 5036 456 10625 9066 8542 8027 7519 7018 6521 6029 5541 5055 457 10375 9155 8624 81 7583 7073 6568 6067 557 5075 4581 10125 925 8709 8177 7651 7131 6617 6107 56 5095 4592 9875 9349 8799 8257 7722 7193 6669 6149 5632 5117 4604 9625 9454 8894 8342 7797 7257 6723 6193 5665 514 4617 9375 9564 8994 8431 7875 7325 678 6239 5701 5165 463 9125 9679 9098 8525 7958 7397 684 6288 5738 519 4644 8875 98 9208 8624 8045 7472 6904 6339 5777 5217 4659 8625 9927 9324 8727 8137 7551 6971 6393 5819 5246 4674 8375 1006 9445 8836 8233 7635 7041 645 5862 5276 4691 8125 102 9572 895 8334 7722 7115 651 5908 5307 4708 7875 1035 9706 907 844 7814 7192 6573 5956 5341 4726 7625 105 9846 9197 8552 7911 7274 664 6007 5376 4745 7375 1066 9994 933 867 8014 7361 671 6061 5413 4766 7125 1083 1015 947 8794 8121 7452 6784 6118 5452 4787 6875 1101 1031 9617 8925 8235 7548 6862 6178 5494 481 6625 112 1049 9773 9063 8356 765 6945 6241 5537 4834 6375 114 1067 9937 9209 8483 7757 7033 6308 5584 4859 6125 1161 1086 1011 9364 8618 7872 7126 638 5634 4887 5875 1183 1106 103 9528 8761 7993 7225 6456 5686 4916 5625 1207 1128 1049 9703 8914 8123 7331 6537 5743 4947 5375 1231 1151 107 9889 9076 8261 7443 6624 5803 498 5125 1258 1175 1092 1009 925 8409 7564 6717 5867 5015 4875 1286 1201 1116 103 9436 8567 7694 6816 5936 5053 4625 1316 1229 1142 1053 9637 8738 7833 6924 601 5094 4375 1349 1259 1169 1078 9853 8922 7983 7039 609 5138 4125 1384 1292 1199 1104 1009 912 8146 7164 6177 5186 3875 1422 1327 1231 1133 1034 9336 8321 7299 627 5237 3625 1463 1365 1266 1165 1062 957 8512 7445 637 5291 3375 1508 1407 1304 1199 1092 9824 8719 7603 6479 middot535 3125 1557 1453 1346 1237 1124 101 8943 7773 6595 5412 2875 1612 1504 1393 1278 116 104 9185 7956 6719 5478 2625 1673 1561 1444 1323 1199 1073 9446 8152 6851 5546 2375 1741 1624 1501 1373 1242 1108 9725 8359 6989 5617 2125 1818 1695 1565 1429 1289 1146 1002 8575 713 5687 1875 1906 1775 1636 149 1339 1186 1032 8792 727 5755 1625 2007 1868 1716 1556 1392 1227 1062 9001 7401 5818
119
1375 1125 875 625 375 125
2127 2271 2449 2679 2994 3436
1975 2103 226
2467 2776 3361
1807 1912 2032 2173 2333 2469
1629 1707 1788 1863 191
1868
1447 1501 1548 1575 1559 1454
1266 1301 1324 1324 1279 1163
109 1111 112
1107 1058 9548
9183 9311 934
9205 8813 8043
7514 7591 7611 7544 735
6956
5873 5918 5953 5988 6049 6199
F6 Freezer Wall Simulation Output Including Anti-sweat Condenser Tube
INPUT PARAMETERS
Section Dimensions (mm) Width Length Depth Steel skin thickness Plastic skin thickness
5600 2000 1580 6500 2500
Mesh Geometry dx dy Number nodes in x-direction Number nodes in y-direction Number of steel skin nodes (including corner 00) Steel nodes under the seal Tube located at node
2800 2500 20 80
11 2 to 10 6
Steel skin conductivity (Wm K)
Foam insulation conductivity (Wm K) Plastic skin conductivity (Wm K)
Outside h (Wm2 K) Inside h (Wm2 K) Outside Temp (C) Inside Temp (C)
5400 27000E-02 1500 6870 6410 2100 -1000
OUPUT PARAMETERS
Number of iterations 879
ID Heat Flux Thru Wall (Wm2) 1362
Heat Transfer Along Metal Skin Under Seal node to node qm[Wm2] Qm[W]
2 3 -15024E+04 -1543 3 4 -15111E+04 -1552 4 5 -15205E+04 -1562 5 6 -15310E+04 -1572 6 7 5828 5986 7 8 5690 5844 8 9 5535 5684 9 10 5348 5492
Maximum difference (Is) 1356
j qleft[W] qright[W] -1 -1566 5928
120
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63
0 -62085E-02 -31363E-02 -5 9522E-02 -40097E-02 -44286E-02 -30955E-02 -33621E-02 -21814E-02 -25242E-02 -1 4577E-02 -1 8767E-02 -9 6252E-03 -13815E-02 -58162E-03 -10387E-02 -31499E-03 -73398E-03 -1 6265E-03 -54353E-03 -10285E-04
-35309E-03 27805E-04 -23882E-03 65891E-04 -16265E-03 14208E-03 -1 24 55E-03 14207E-03 -48371E-04 14207E-03 -10285E-04 10398E-03 -10285E-04 10399E-03 -10281E-04 10398E-03 -48371E-04 65891E-04 -1 02 85E-04 27805E-04 -86465E-04 16377E-04 -48375E-04 -52182E-04 -86465E-04 -97886E-04 -1 2455E-03 -13979E-03 -1 7788E-03 -16645E-03 -19692E-03 -21597E-03 -24263E-03 -25786E-03 -30357E-03 -30357E-03 -33404E-03 -35309E-03 -3 7975E-03 -3 9879E-03 -41784E-03 -44450E-03 -45974E-03 -49402E-03 -50164E-03 -53592E-03 -54353E-03 -58162E-03 -58543E-03 -62733E-03 -62733E-03 -66923E-03 -66542E-03 -71493E-03 -70351E-03 -75303E-03 -74541E-03 -7 9111E-03 -77969E-03 -83301E-03 -81397E-03 -87491E-03 -85206E-03 -90919E-03 -88634E-03 -94728E-03 -92062E-03 -97775E-03 -95109E-03 -10158E-02 -98537E-03 -10463E-02 -1 0158E-02 -10768E-02 -1 04 63E-02 -11073E-02 -10692E-02 -11377E-02 -10996E-02 -11644E-02 -11225E-02 -1 1949E-02 -11492E-02 -12215E-02 -11758E-02 -12444E-02 -11949E-02 -12672E-02 -12177E-02 -12901E-02 -12368E-02 -13129E-02 -12596E-02 -1 3282E-02 -12748E-02 -1 351 OE-02 -1 2977E-02 -13701E-02 -13129E-02 -1 3853E-02 -13282E-02 -14005E-02 -1 3434E-02 -14158E-02 -13586E-02 -14310E-02 -1 3701E-02 -14463E-02
121
64 -1 3815E-02 -1 4577E-02 65 -1 392 9E-02 -14691E-02 66 -14005E-02 -14767E-02 67 -14120E-02 -14881E-02 68 -14196E-02 -14958E-02 69 -1 4272E-02 -15034E-02 70 -14310E-02 -15110E-02 71 -1 4386E-02 -1 5148E-02 72 -14424E-02 -15186E-02 73 -14463E-02 -15224E-02 74 -14501E-02 -1 5262E-02 75 -14501E-02 -1 5300E-02 76 -14539E-02 -15262E-02 77 -14539E-02 -15300E-02 78 -1 4539E-02 -15262E-02 79 -14501E-02 -1 5300E-02
Qleft [Wj -1653 Qright [Wj 5163 Percent entering cabinet 2380
Freezer Nodal Temperatures (Condenser Tube)
x(mm) y(mm) 14 42 70 98 126 154 182 210 238 266
19875 9606 8457 7334 6235 516 4107 3075 2064 107 00944 19625 9596 8448 7325 6227 5152 4099 3068 2056 1064 00882 19375 9591 8443 732 6222 5148 4095 3064 2053 106 00850 19125 9591 8443 732 6222 5147 4095 3064 2052 106 00847 18875 9596 8448 7325 6226 5151 4099 3067 2056 1063 00873 18625 9606 8457 7334 6235 5159 4106 3074 2062 1069 00928 18375 9621 8472 7347 6248 5171 4118 3085 2072 1078 01013 18125 9641 8491 7366 6265 5188 4133 3099 2085 109 01128 17875 9666 8514 7388 6287 5208 4152 3117 2102 1106 01272 17625 9696 8543 7416 6313 5233 4176 3139 2123 1125 01447 17375 9731 8577 7448 6343 5262 4203 3165 2147 1147 01652 17125 9772 8616 7485 6378 5295 4234 3194 2174 1173 01888 16875 9817 8659 7526 6418 5333 427 3228 2206 1202 02156 16625 9868 8708 7573 6462 5375 431 3265 224 1234 02455 16375 9924 8762 7624 6511 5421 4353 3306 2279 127 02786 16125 9985 8821 7681 6565 5472 4402 3352 2322 131 03149 15875 1005 8885 7742 6624 5528 4454 3401 2368 1353 03546 15625 1012 8954 7809 6687 5588 4511 3455 2418 1399 03976 15375 102 9029 7881 6755 5653 4573 3513 2472 145 04441 15125 1029 911 7958 6829 5723 4639 3575 253 1504 0494 14875 1038 9196 804 6907 5798 4709 3641 2592 1562 05474 14625 1047 9287 8128 6991 5877 4784 3712 2659 1623 06045 14375 1057 9385 8221 708 5962 4865 3787 2729 1689 06652 14125 1068 9488 832 7175 6052 495 3868 2804 1759 07297 13875 1079 9597 8424 7275 6147 504 3952 2884 1833 07981 13625 1091 9713 8535 738 6247 5135 4042 2968 1911 08704 13375 1104 9834 8651 7491 6353 5235 4136 3056 1993 09466 13125 1117 9962 8774 7608 6464 534 4236 315 208 1027 12875 1131 101 8902 7731 6581 5451 434 3248 2172 1112 12625 1146 1024 9037 786 6704 5568 445 3351 2268 1201 12375 1161 1038 9178 7995 6833 569 4566 3459 2369 1294
122
12125 1177 1054 9326 8136 6967 5818 4686 3572 2475 1392 11875 1194 107 9481 8284 7108 5951 4813 3691 2585 1494 11625 1211 1087 9642 8439 7256 6091 4945 3815 2701 1602 11375 1229 1104 981 86 7409 6237 5083 3945 2822 1714 11125 1248 1122 9985 8768 757 639 5227 4081 2949 1832 10875 1268 1141 1017 8943 7737 6549 5378 4222 3082 1954 10625 1288 1161 1036 9125 7911 6714 5534 437 322 2083 10375 1309 1181 1055 9314 8092 6887 5698 4524 3364 2217 10125 1331 1203 1076 9511 8281 7067 5868 4685 3514 2356 9875 1354 1225 1097 9716 8477 7254 6046 4852 3671 2502 9625 1378 1248 1119 9929 8681 7448 6231 5026 3835 2654 9375 1402 1271 1142 1015 8893 7651 6423 5208 4005 2813 9125 1428 1296 1166 1038 9113 7861 6623 5398 4183 2979 8875 1454 1321 1191 1062 9342 808 6832 5595 4369 3152 8625 1481 1348 1216 1086 9579 8308 7049 5801 4562 3333 8375 1509 1375 1243 1112 9826 8545 7275 6015 4764 3522 8125 1538 1403 127 1139 1008 8791 751 6238 4975 3719 7875 1568 1432 1299 1166 1035 9047 7755 6472 5196 3925 7625 1598 1462 1328 1195 1063 9314 8011 6715 5426 4142 7375 163 1494 1358 1224 1091 9591 8278 697 5667 4368 7125 1663 1526 139 1255 1121 9881 8556 7236 5919 4606 6875 1697 1559 1422 1287 1152 1018 8847 7514 6184 4855 6625 1731 1593 1456 132 1185 105 9151 7806 6462 5118 6375 1767 1629 1491 1355 1218 1083 9469 8113 6755 5394 6125 1804 1665 1527 139 1254 1117 9804 8435 7063 5686 5875 1842 1703 1565 1428 129 1153 1015 8774 7388 5995 5625 1881 1742 1604 1466 1329 1191 1052 9133 7732 6322 5375 1921 1782 1644 1507 1369 1231 1091 9511 8097 6669 5125 1962 1824 1686 1549 1411 1272 1133 9913 8485 7039 4875 2004 1867 173 1593 1455 1317 1176 1034 8899 7435 4625 2047 1912 1776 164 1502 1363 1223 108 9341 7859 4375 2092 1958 1823 1688 1552 1413 1272 1128 9816 8315 4125 2138 2005 1873 1739 1604 1466 1325 1181 1033 8807 3875 2184 2055 1925 1793 166 1523 1382 1238 1088 934 3625 2232 2106 1979 1851 1719 1584 1444 1299 1148 992 3375 2282 216 2037 1911 1783 1649 1511 1366 1214 1055 3125 2332 2215 2097 1976 1851 1721 1584 1439 1286 1125 2875 2384 2273 2161 2045 1925 1798 1663 152 1366 1202 2625 2436 2334 2229 212 2005 1883 1751 1609 1455 1288 2375 249 2397 2301 22 2093 1976 1849 1708 1554 1384 2125 2546 2463 2377 2287 2188 2079 1957 182 1666 1493 1875 2602 2532 2459 238 2293 2193 2079 1946 1793 16 17 1625 266 2605 2546 2482 2407 232 2215 2089 1939 176 1375 2719 2681 264 2592 2533 2461 2369 2253 2108 1928 1125 2779 2761 2739 271 2671 2618 2543 244 2305 2128 875 2841 2844 2844 2838 2822 2792 2739 2655 2535 2367 625 2903 293 2954 2974 2986 2984 2959 2899 2802 2658 375 2967 3018 3069 3117 316 3194 3209 3173 3108 3009 125 3032 3108 3186 3263 3342 3421 35 347 344 3412
x (nun) y (nun) 294 322 350 378 406 434 462 490 518 546
19875 -0865 -1811 -2743 -3663 -4573 -5474 -6368 -7257 -8141 -9022 19625 -0871 -1816 -2747 -3667 -4577 -5477 -6371 -7259 -8142 -9024 19375 -0874 -1819 -275 -3669 -4578 -5479 -6372 -726 -8143 -9024 19125 -0874 -1819 -275 -367 -4579 -5479 -6372 -726 -8144 -9025 18875 -0872 -1817 -2748 -3668 -4577 -5478 -6372 -7259 -8143 -9025
123
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124
4125 7246 5647 4014 2349 06577 -1055 -2785 -4528 -6279 -8036 3875 775 6116 444 2728 0986 -0780 -2565 -4362 -6168 -7978 3625 8299 6625 4902 3137 1339 -0486 -233 -4187 -6051 -7919 3375 8899 718 5404 3579 1717 -0173 -2082 -4003 -593 -7859 3125 9558 7787 595 4057 2122 01586 -1823 -3813 -5806 -7798 2875 1028 8455 6545 4573 2555 0508 -1553 -3618 -568 -7739 2625 1109 9192 7197 513 3014 0872 -1277 -3422 -5558 -7683 2375 12 1001 7912 5729 3497 1245 -1002 -3233 -5442 -7633 2125 1301 1093 8698 6373 3998 1618 -0739 -3059 -534 -7592 1875 1418 1196 9566 7058 4508 1975 -0503 -2914 -5262 -7564 1625 1552 1314 1053 778 5007 2292 -0319 -2818 -5218 -7554 1375 171 1452 116 8525 5462 2528 -0224 -2798 -5226 -7564 1125 19 1616 1281 9263 5815 2621 -0272 -2892 -5304 -7597 875 2136 182 1417 9928 5968 2477 -0537 -3151 -5478 -7651 625 244 2095 1569 1037 575 1953 -112 -3637 -5773 -7713 375 2845 2514 1726 1027 4873 0854 -2146 -4427 -6224 -7757 125 3384 3296 1814 8879 2904 -1057 -3745 -5602 -6885 -7725
F bull 7 Seal Simulation Source Code and Ouput
Program Seal
c This program simulates the heat transfer characteristics of an c idealized refrigerator door gasket The steady-state temperature c profile is determined numerically from a 2-D finite difference c code
cxxxxxxxxxxxxx Parameters and Variablesxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
integer NNNWnsurfijjlloopiters real emmissigmakhihoTiTodelsNN real depthareatolkair
parameter (N=6) parameter (NN=20) parameter (W=7) parameter (nsurf=4N-l) parameter (emmis=09) parameter (sigma=567e-8) parameter (k=03) parameter (kair=0026) parameter (hi=641) parameter (ho=687) parameter (Ti=1032) parameter (To=209) parameter (sNN=02) parameter (del=sNNNN) parameter (depth=10) parameter (area=deldepth) parameter (tol=10)
real x(Onsurf)y(Onsurf)len(ONOnsurf) real F(OnsurfOnsurf) real T(-lNN+lONN)radl(nsurf+l)rad(Onsurf) real Eb(Onsurf)bvector(nsurf+l)Amatrix(nsurf+lnsurf+l) real difasumqsumqtotqin(NN-l) real rlr2r3r4r5
125
real clc2c3c4c5c6c7
open (lfilemiddotGasketoutposition-rewind) open (2file=Gasket(q)outpositionmiddotrewind)
cxxxxxxxxxxxxx Determine Viewfactors xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
call Points(Ndelnsurfxy) call length(Ndelnsurfxylen) call Vfactor(NdelnsurflenF)
cxxxxxxxxxxxxx Resistors (C-m2W)
c Interior x- and y-directions rl=delk
c Exterior to outdoor ambient r2=1ho
c Exterior to indoor ambient r3-1hi
c Radiation r4=(1-emmis)emmis
c Air r5=delkair
xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
cxxxxxxxxxxxxx Guass-Siedel Iteration xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
c Begin massive loop to determine the steady-state temperature c distribution across the section First update the interior nodes c by considering the radiative heat transfer among the interior c surfaces The radiative transfer is updated by calling a routine c which computes the new radiosities every iteration Loop until c tolerance is met
c Initialize temperature field do 10 i=ONN
do 11 jONN T(ij)=50
11 continue 10 continue
do 15 j=ONN T(-1j)=250 T(NN+lj)=50
15 continue
c Set temperatures for row y=O and row y=NN do 20 i=ONN
T(iO)=fl(idel) T(iNN)=f2(idel)
20 continue
cxxxxxxxxxxxxx Begin Iteration xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
loop=l iters=l do while (loop eq 1)
c Update radiosities using new temps and update interior surface nodes
call Jsolver(FemmissigmaTNNNWnsurfradlradEb + bvectorAmatrix)
c interior corners cl=area (2rl) c2=arearl
126
c3=area (2rl) c4=arearl c5=arear4 c6=1(cl+c2+c3+c4)
T(WW)=c6(clT(W+lW)+c2T(W-lW)+c3T(WW+l)+ + c4T(WW-l)+c5(rad(0)-Eb(0raquo)
cl=arearl c2=area(2rl) c3=area(2rl) c4=arearl c5=arear4 c6-1(cl+c2+c3+c4) T(W+NW)=c6(clT(W+N+lW)+c2T(W+N-lW)+c3T(W+NW+l)+
+ c4T(W+NW-l)+c5(rad(N)-Eb(Nraquo) clarearl c2-area (2rl) c3-arearl c4=area(2rl) c5=arear4 c6=1(cl+c2+c3+c4) T(W+NW+N)=c6 (clT(W+N+lW+N)+c2T(W+N-lW+N) +c3T(W+NW+N+l)+
+ c4T(W+NW+N-l)+c5(rad(2N)-Eb(2Nraquo) cl=area(2rl) c2=arearl c3=arearl c4=area(2rl) c5=arear4 c6=1(cl+c2+c3+c4) T(WW+N)=c6 (clT(W+lW+N) +c2T(W-lW+N)+c3T(WW+N+l) +
+ c4T(WW+N-l)+c5(rad(3N)-Eb(3Nraquo)
c Interior surface y=W jl=l do 22 i=W+lW+N-l
cl=area(2rl) c2=area (2rl) c4=arearl c5=arear4 c7=arear5 c6=1(cl+c2+c4+c7) T(iW)=c6(clT(i+lW)+c2T(i-lW)+
+ c7T(iW+l)+c4T(iW-l)+c5(rad(jl)-Eb(jlraquo) jl=j1+1
22 continue
c Interior surface y=N+W jl=3N-l do 25 i=W+lW+N-l
cl=area(2rl) c2=area (2rl) c3=arearl c5=arear4 c7=arear5 c6=1(cl+c2+c3+c7) T(iW+N)=c6(clT(i+lW+N)+c2T(i-lW+N)+
+ c7T(iW+N-l)+c3T(iW+N+l)+c5(rad(jl)-Eb(jlraquo) jl=jl-l
25 continue
c interior surface x=W jl=4N-l do 30 j=W+lW+N-l
c2=arearl
127
c3=area (2rl) c4=area(2rl) c5-arear4 c7-arear5 c6-1(c2+c3+c4+c7) T(Wj)-c6(c7T(W+lj)+c2T(W-lj)+c3T(Wj+l)+
+ c4T(Wj-l)+c5(rad(jl)-Eb(jl))) jl=jl-l
30 continue
c interior surface x=W+N jl=N+l do 35 j-W+lW+N-l
cl=arearl c3=area(2rl) c4=area (2rl) c5-arear4 c7-arear5 c6-1(cl+c3+c4+c7) T(W+Nj)=c6(clT(W+N+lj)+c7T(W+N-lj)+c3T(W+Nj+l)+
+ c4T(W+Nj-l)+c5(rad(jl)-Eb(jl))) jl=j1+1
35 continue
c Interior air nodes do 37 j=W+lN+W-l
do 38 i=W+lN+W-l call sseqn(Tr5r5r5r5areaareaareaareaijNN)
38 continue 37 continue
c Solid nodes do 40 i=lNN-l
do 45 jlW-l call sseqn(TrlrlrlrlareaareaareaareaijNN)
45 continue do 50 j=W+N+lNN-l
call sseqn(TrlrlrlrlareaareaareaareaijNN) 50 continue 40 continue
do 55 j=WW+N do 60 i=lW-l
call sseqn(TrlrlrlrlareaareaareaareaijNN) 60 continue
do 65 i=W+N+lNN-l call sseqn(TrlrlrlrlareaareaareaareaijNN)
65 continue 55 continue
c Side boundaries do 70 j=lNN-l
call sseqn(Trlr2rlrlareaareaarea2area20jNN) call sseqn(Tr3rlrlrlareaareaarea2area2NNjNN)
70 continue
c Apply energy balance around the boundary of the gasket to determine c stopping criterium dif
dif-OO dif=dif+(area(2rl))(T(00)-T(01)) dif=dif+(area(2rl))(T(0NN)-T(0NN-l)) do 90 i=lNN-l
dif=dif+(arearl)(T(iO)-T(il)) dif=dif+(arearl)(T(iNN)-T(iNN-l))
128
90 continue dif=dif+(area(2r1raquo(T(NN0)-T(NN1raquo dif=dif+(area(2r1raquo(T(NNNN)-T(NNNN-1raquo
do 95 j=1NN-1 dif=dif+(arear2)(To-T(0jraquo dif-dif+(arear3)(Ti-T(NNjraquo
95 continue
print dif
c Stopping criterium if (dif It toll then
loop-O endif if (iters eq 10000) then
loop=O endif
iters=iters+1 end do
cxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx c Compute heat flux into the cabinet
qsum=OO asum=OO do 97 j=1NN-1
qin(j)=hiarea(T(NNj)-Ti) qsum=qsum+qin(j) asum=asum+area
97 continue qtot=qsumasum write(2) heat flux to interior [Wm2)qtot
do 100 j=NNO-l write(l) (T(ij)i=ONN)
100 continue
pause stop end
c----------------------------------------------------------------------shyc------~----------------------------------------------------------------
Subroutine Points(Ndelnsurfxy)
integer Nnsurfi real delincrx(Onsurf)y(Onsurf)
x(O)=OO y(0)=del2
c Points along y=O edge incr-OO do 10 i=lN
y(i)=OO x(i)=(del2)+incr incr=incr+del
10 continue
c Points along x=Ndel edge incr=OO do 20 i=N+12N
x(i)=Ndel
129
y(i)-(del2)+incr incr-incr+del
20 continue
c Points along y=Ndel edge incr=OO do 30 i=3N2N+l-1
y(i)-Ndel x(i)=(del2)+incr incr-incr+del
30 continue
c Points along x-O edge incr=OO do 40 i-nsurf3n+l-1
xli) -00 y(i)-laquo3del)2)+incr incr-incr+del
40 continue
return end
c----------------------------------------------------------------------shyc-----------------------------------------------------------------------
Subroutine length(Ndelnsurfxylen)
integer Nnsurfij real dellen(ONOnsurf)x(Onsurf)y(Onsurf)
c Special case surface 0 do 10 j=Onsurf
len(0j)=sqrtlaquox(0)-x(jraquo2+(y(0)-y(jraquo2) 10 continue
c Surfaces along y=O do 20 i=IN-l
do 30 j=Onsurf len(ij)=sqrtlaquox(i)-x(jraquo2+(y(i)-y(jraquo2)
30 continue 20 continue
c Special case surface N do 50 j=Onsurf
len(Nj)=sqrtlaquox(N)-x(jraquo2+(y(N)-y(jraquo2) 50 continue
return end
c----------------------------------------------------------------------shyc-----------------------------------------------------------------------
Subroutine Vfactor(NdelnsurflenF)
integer Nnsurfijjlj2 real dellen(ONOnsurf)F(OnsurfOnsurf)Lzero
c Determine viewfactors for special case of surface 0 Lzero=delsqrt(20) do 10 j=Onsurf
if (j eq 0) then F(Oj)=OO
elseif (j eq nsurf) then F(Oj)=(len(Oj)+len(10)-len(00)-len(ljraquo(2Lzero)
else F(0j)=(len(0j)+len(lj+l)-len(Oj+l)-len(ljraquo(2Lzero)
130
endif 10 continue
c Determine viewfactors for surfaces on edge y-O
do 20 i=IN-l do 30 j=Onsurf
if (i eq j) then F(ij)=OO
elseif (j eq nsurf) then F(ij)=(len(ij)+len(i+l0)-len(i0)-len(i+ljraquo(2de1)
else F(ij)=(len(ij)+len(i+lj+l)-len(ij+l)-len(i+ljraquo(2del)
endif sum=sum+F(ij)
30 continue 20 continue
c Determine viewfactors for all other surfaces do 40 iON-l
do 50 j=03N-l F(i+Nj+N)=F(ij)
50 continue do 60 j=3Nnsurf
F(i+Nj-3N)=F(ij) 60 continue
do 70 j=02N-1 F(i+2Nj+2N)=F(ij)
70 continue do 80 j=2Nnsurf
F(i+2Nj-2N)=F(ij) 80 continue
do 90 j=ON-l F(i+3Nj+3N)=F(ij)
90 continue do 100 j=Nnsurf
F(i+3Nj-N)=F(ij) 100 continue
40 continue
return end
c----------------------------------------------------------------------shyc-----------------------------------------------------------------------
Subroutine Jsolver(FemmissigmaTNNNWnsurfradlradEb + bvectorAmatrix)
integer NNNnsurfij real emmissigmaF(OnsurfOnsurf) real T(-INN+10NN)rad1(nsurf+l)rad(0nsurf) real Eb(0nsurf)bvector(nsurf+1)Amatrix(nsurf+lnsurf+l)surn
c Compute Eb for all surfaces do 10 i-ON-l
Eb(i)=sigma(T(i+WW) 4) Eb(i+N)=sigma(T(W+Ni+W)4)
10 continue incr=W+N do 20 i=0N-1
Eb(i+2N)=siqrna(T(incrW+N) 4) Eb(i+3N)=sigma(T(Wincr)4) incr=incr-1
20 continue
131
c Assign values to vector b do 30 i=Onsurf
bvector(i+l)-(emmis(l-emmisraquoEb(i) 30 continue
c Assign values to matrix A do 40 i-Onsurf
do SO j=Onsurf Amatrix(i+lj+l)--F(ij)
SO continue 40 continue
c Override diagonal terms do 60 i-Onsurf
sum-OO do 70 j-Onsurf
sum-sum+F(ij) 70 continue
Amatrix(i+li+l)-(emmis(l-emmisraquo+sum 60 continue
c Call routine to solve the set of equations for unknown JS call gaussy(Amatrixbvectorradlnsurf+l)
do 80 i=Onsurf rad(i)=radl(i+l)
80 continue
return end
c----------------------------------------------------------------------shyc-----------------------------------------------------------------------
Subroutine Gaussy(abxn) c
integer nkiimaxjkplusllplus real a(nn)b(n)x(n)amaxbtempatemp
+ aeon sum
do 28 k=l n amax=OO do 4 i=kn if(abs(a(ikraquo-abs(amaxraquo442
2 amax=a(ik) imax=i
4 continue if(abs(amax)-0le-15)101014
10 printO equations are not independent return
14 btemp=b(k) b(k)=b(imax) b(imax)=btemp do 18 j=kn
atemp=a(k j) a(kj)=a(imaxj)
18 a(imaxj)=atemp kplus=k+l if(k-n)222828
22 do 24 i=kplusn b(i)=b(i)-b(k)a(ik)a(kk) acon=a(ik) do 24 j=kn
24 a(ij)=a(ij)-a(kj)acona(kk) 28 continue
132
l=n 32 sum=OO
if(1-n)343838 34 lplus-1+1
do 36 j-lplusn 36 sum=sum+a(lj)x(j) 38 continue
x(l)-(b(l)-sum)a(ll) if(1-1)424240
40 1-1-1 goto 32
42 return end
c----------------------------------------------------------------------shyc-----------------------------------------------------------------------
Subroutine sseqn(TriplusriminusrjplusrjminusAiplus + AiminusAjplusAjminusijNN)
c This subroutine computes the temperature at node (ij) c given the temperatures of the surrounding nodes and c the resistances leading to these nodes
integer ijNN real T(-1NN+10NN)riplusriminusrjplusrjminus real AiplusAiminusAjplusAjminus real c1c2c3c4c5
c1=Aiplusriplus c2=Aiminusriminus c3=Ajplusrjplus c4=Ajminusrjminus c5=1(c1+c2+c3+c4)
T(ij)=c5(c1T(i+1j)+c2T(i-1j)+c3T(ij+1)+c4T(ij-1raquo
return end
c----------------------------------------------------------------------shyc----------------------------------------------------------------------shy
real function f1(x) c door BC
real x f1-18520 - 23413x
return end
c----------------------------------------------------------------------shyc----------------------------------------------------------------------shy
real function f2(x) c wall BC
real x f2=18128 - 3475x
return end
c----------------------------------------------------------------------shyc----------------------------------------------------------------------shy
133
Fresh Food Compartment Simulations Results
Run 1 The prescribed temperature profiles are
Wall 19203 - 1908 x Door 19203 - 1206 x
(x is in meters)
Outdoor Ambient = 210 degC Local Indoor Ambient = 1533 degC
Run 2 The prescribed temperature profiles are
Wall 18989 - 2024 x Door 19078 - 1326 x
(x is in meters)
Outdoor Ambient = 210 degC Local Indoor Ambient = 1496 degC
Run 3 The prescribed temperature profiles are
Wall 1895 - 1998 x Door 19053 - 1384 x
(x is in meters)
Outdoor Ambient = 208 degC Local Indoor Ambient = 1491 degC
Ayem~ Values Wall 1905 - 1977 x Door 1913 - 1384 x
(x is in meters)
Ave Outdoor Ambient = 209 degC Ave Local Indoor Ambient =1507 degC
Loss from Fresh Food == 10 W
134
Freezer Compartment Simulations Results
Run 1 The prescribed temperature profiles are
Wall 1821 - 343 x Door 18606 - 2354 x
(x is in meters)
Outdoor Ambient = 210 degC Local Indoor Ambient = 1029 degC
Run 2 The prescribed temperature profiles are
Wall 18182 - 3542 x Door 18544 - 2398 x
(x is in meters)
Outdoor Ambient = 210 degC Local Indoor Ambient = 1042 degC
Run 3 The prescribed temperature profiles are
Wall 17993 - 3452 x Door 18411 - 2272 x
(x is in meters)
Outdoor Ambient = 208 degC Local Indoor Ambient = 1024 degC
Ayera~e Values Wall 18128 - 3475 x Door 18520 - 23413 x
(x is in meters)
Ave Outdoor Ambient = 209 degC Ave Local Indoor Ambient = 1032 degC
Loss from Fresh Food = 157 W
135
TABLE OF CONTENTS (CONTINUED)
Page APPENDIX A FUMED SILICA INVESTIGATION 56
Al Introduction56 A2 Thermal Properties 56 A3 Experimental Method 57 A4 Theory57 A5 Test Apparatus 59 A6 Results 61 A7 Conclusions 65 A8 Thermal Diffusivity Newton-Raphson Iteration Source Code 65
APPENDIX B ONE-DIMENSIONAL SIMULATION SOURCE CODE AND OUTPUT 69
Bl Source Code 69 B2 Output 71
APPENDIX C TEST REFRIGERATOR DESCRIPTION 73
APPENDIX D DATA ACQUISITION AND CONTROL SYSTEM 77
APPENDIX E EXPERIMENTAL DATA AND PLOTS 79
El Temperature Profile Plots From Fixed Thermocouples 79 E2 Thermopile Data Reduction 81 E3 Experimental Determination of qwall and qdoor Details 82 E4 Temperature Profile Plots From Mullion Data (Heater Off) 84 E5 Temperature Profile Plots From Mullion Data (Heater On) 87
APPENDIX F NUMERICAL SIMULATION EQUATIONS AND CODE 92
Fl Finite-Difference Equations 92 F2 Wall Simulation Source Code 94 F3 Fresh Food Wall Simulation Output 102 F4 Freezer Wall Simulation Output 108 F5 Fresh Food Wall Simulation Output Including
Anti-sweat Condenser Tube 115 F6 Freezer Wall Simulation Output Including
Anti-sweat Condenser Tube 120 F7 Seal Simulation Source Code and Output 125
vi
LIST OF TABLES
Page
31 One-dimensional Model Parameters 8 32 Results from One-dimensional Load Analysis 10
41 Thermopile Output 16 42 Experimental Determination of qwall and qdoor 20 43 Experimental Results from Mullion Analysis 24 44 Experimental Results from Heater Analysis 26 45 Miscellaneous Loads 27
51 Wall Simulation Input 30 52 Input Values 32 53 Wall Simulation Results 33 54 Wall With Condenser Tube Simulation Results 36 55 Seal Simulation Input 42 56 Seal Simulation Results 43
61 Comparison of Simulation and Experimental Values for qwall and qdoor 48 62 Overall Cabinet Loads 51
A1 Average Fumed Silica Conductivity for Various Bulk Densities 63 A2 Average Fumed Silica Diffusivity for Various Bulk Densities 64
E1 Thermopile Raw Data 82
F1 Model Resistors 92
V1l
LIST OF FIGURES
Page 11 Door Seal Region Cross Section 3 12 Mullion Region Cross Section 4
31 Model Used To Calculate One-dimensional Load 7
41 SteelSkin Temperature Profile Thermocouple Placement 12 42 Steel Skin Temperature Plot for Fresh Food Compartment 13 43 Steel Skin Temperature Plot for Freezer 14 44 Thermopile Test Apparatus 15 45 Thermopile Placement ~ 16 46 Thermocouple Drag Test Apparatus 17 47 Drag Profiles (Fresh Food) 18 48 Drag Profiles (Freezer) 19 49 Heat Flow Paths in Mullion 21 410 Mullion Face Plate Cross Section 22 411 Mullion Temperature Profile 23 412 Electric Heater Location 25 413 Mullion Temperature Profile With Heater On (Center) 26
51 Wall Heat Conduction Model Sketch 29 52 Non-adiabatic Door Seal 31 53 Fresh Food Wall Temperature Distribution 34 54 Freezer Wall Temperature Distribution 35 55 Tube Location for Simulation 36 56 Fresh Food Wall Temperature Distribution
Including Warm Anti-sweat Tube 37 57 Freezer Wall Temperature Distribution
Including Warm Anti-sweat Tube 38 58 Load Due to Condenser Tube for Various Tube Placements 39 59 ~ercentage of Heat Entering Cabinet for Various Tube Placements 39 510 Seal Simulation Mesh Layout 40 511 Seal Cavity Mesh Details 41 512 Seal Temperature Distribution (Fresh Food) 44 513 Seal Temperature Distribution (Freezer) 45
61 Refrigerator System Load Graph 46 62 Cabinet Loads Graph 47
A1 Fumed Silica Test Apparatus 59 A2 Fumed Silica Test Facility Schematic 60 A3 Time vs Temperature for Unpacked Run 61 A4 Natural Log Time vs Temperature for Unpacked Run 62 A5 Conductivity vs Bulk Density 63 A5 Diffusivity vs Bulk Density 64
viii
LIST OF FIGURES (CONTINUED)
Page
C1 Location of Anti-sweat Devices and Overall Dimensions of Test Refrigerator 73
C2 Fresh Food Compartment Interior Dimensions 74 C3 Fresh Food Door75 C4 Freezer Interior Dimensions 76 C5 Freezer Door76
D1 Data Acquisition and Control System 78
E1 Steel Skin Temperature Plot for Fresh Food Compartment (Run 2) 79 E2 Steel Skin Temperature Plot for Fresh Food Compartment (Run 3) 80 E3 Steel Skin Temperature Plot for Freezer (Run 2) 80 E4 Steel Skin Temperature Plot for Freezer (Run 3) 81 E5 Mullion Temperature Profile Run 2 (Heater Off) 84 E6 Mullion Temperature Profile Run 3 (Heater Off) 85 E7 Mullion Temperature Profile Run 4 (Heater Off) 85 E8 Mullion Temperature Profile Run 5 (Heater Off) 86 E9 Mullion Temperature Profile Run 2 (CenterHeater On) 87 E10 Mullion Temperature Profile Run 3 (CenterHeater On) 88 E11 Mullion Temperature Profile Run 1 (LeftHeater On) 88 E12 Mullion Temperature Profile Run 2 (LeftHeater On) 89 E13 Mullion Temperature Profile Run 3 (LeftHeater On) 89 E14 Mullion Temperature Profile Run 1 (RightHeater On) 90 E15 Mullion Temperature Profile Run 2 (RightHeater On) 90 E16 Mullion Temperature Profile Run 3 (RightHeater On) 91
F1 Generic Nodal Resistor Network 92
IX
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1 INTRODUCTION
New regulations recently announced by the Department ofEnergy call for substantial
energy efficiency increases for household appliances by 1993 The refrigerator is of
particular interest since it is the largest household consumer of electricity and accounts for a
large part of the 8 of the electricity used in the US for food-cooling both residential and
commercial In addition to efficiency standards regulations are being imposed on the use
of CFCs completely banning their use by the year 2000 (Braswell 1988)
The objective of this thesis is to present an analysis of all heat transfer paths from the
surroundings to the interior food compartments of the refrigerator under closed door
conditions Both experimental and numerical methods are used as a means to determine the
overall cabinet load as well as the load due to each pathway The study is focused on a
particular unit for practical purposes However the methods implemented may be applied
to any make or model to aid in the search for high efficiency cabinets
All loads determined in this study are strictly cabinet loads and not the loads seen by the
refrigerator system The thermal load on the cabinet is comprised of three main parts (i)
the load due to the one-dimensional heat transfer through the walls and doors to the food
compartments away froin the edges (ii) the load due to edge effects that is heat transfer
into the food storage compartments via paths around the perimeter of the cabinet aperture
and (iii) other miscellaneous sources
(11)
The determination of qlD is straightforward and is discussed in detail in Chapter 3 The
edge load must be broken down into several parts for examination
qedge = qwall + qdoor + qseal + qrnullon + qtubeave (12)
where
qwall heat input due to conduction along the wall steel flange
qdoo heat input due to conduction along the door steel flange
qseal heat conduction directly through the door seal
1
heat input due to conduction in the mullion region with the additional input from an anti-sweat heater
qtubeave heat input due to cabinet anti-sweat condenser tube averaged over the cycle time
heat input due to cabinet anti-sweat condenser tube
heat input due to conduction in the mullion region electric heater off
It is assumed that an electric anti-sweat heater in the mullion region is in use for the entire
cycle The test unit chosen for this study required this region to be heated almost
continually to eliminate condensation This load is represented by qmulloo in Eq (12)
The load qmulloff is due to heat conduction to the interior compartments at the mullion
region when the electric heater is off Although this value does not appear in the edge load
definition it is still important to detennine for sake of comparison with the value of
qmulloo The load due to the presence of an anti-sweat condenser loop around the aperture
of the cabinet is defmed as qtube Since this load is present for the on cycle only it must be
integrated over the cycle time to be included in Eq (12) hence the tenn qtubeave
The tenn qroisc is expressed as
qmisc = qfanave + qdefrostave + qcompave (13)
where
qfanave heat input from the evaporator fan averaged over the cycle time
qdefrostave heat input from the defrost heaters averaged over defrost cycle time
qcompave heat input from elevated exterior walls near the running compressor
Figure 11 is a cross sectional drawing of the door seal area of the test refrigerator
examined to detennine qwalI qdoor and~ The figure includes materials and their
properties taken from Incropera and Dewitt (1985)
2
400 ~I-I~ 065~
065 Only dimension that is different for the freezer
200
kltWIm-K)
Outer Steel Skin 540 312~ Polyurethane Wall Insulation 0027 0015- Inner Plastic Skin 015 009~
~ Rubber Gasket 03 017fm1I ~ ~ Glass Fiber Door Insulation 004 0023
All dimensions in millimeters
1 in= 254mm
Fig 11 Door Seal Region Cross Section
3
Figure 12 is a drawing of the mullion region cross section of the test refrigerator examined
to detennine ltlmullon and ltlmulloff
FREEZER
Freezer Gasket
Fresh Food Gasket
FRESH FOOD COMPARTMENT
Fig 12 Mullion Region Cross Section
The remainder of this thesis is devoted to the analysis of the closed door cabinet loads and
the experimental and numerical techniques used for their detennination
An experimental investigation of fumed silica as an alternative insulation for the refrigerator
is presented in Appendix A Although this appears to be a departure from the main topic
a relation exists The desire of higher efficiency requires a search for equal if not better
cabinet insulations that do not incorporate the use of ozone damaging CFCs Testing is
done to detennine the thennal conductivity and diffusivity of fumed silica for several
densities
4
2 LITERATURE REVIEW
The new energy standards imposed by the Department ofEnergy have sparked research in
the area of refrigerator efficiency and alternative refrigerants A study by Turiel and
Heydari (1988) focused on several ways to improve the efficiency of refrigerator-freezers
and freezers
Various classes for the study were chosen however the paper presents extensive results for
the most common variety a top-mounted automatic defrost refrigeratorfreezer The
design options considered were those changes that can be incorporated into the existing
refrigerator design Two types of improvements are noted (i) changes that increase energy
efficiency by decreasing the heat transfer into the cabinet and (ii) changes that increase the
efficiency by reducing auxiliary electricity use or improving the refrigeration system Type
(i) changes include Foam insulation substitution increased insulation thickness double
door gaskets improved foam insulation evacuated insulation panels and reduced heat load
of through-the-door feature Type (ii) changes include High efficiency compressor
substitution adaptive defrost fan and fan motor improvement anti-sweat heater switch
increased evaporator surface area hybrid evaporator enhanced heat transfer surfaces
mixed refrigerants improved expansion valve fluid control valve two-compressor system
use of natural convective currents and location of compressor condenser and evaporator
fan motor
Turiel and Heydari used a model developed by Little (1982) to carry out the energy use
simulations This model is a steady-state energy use simulation which computes the heat
leakage to the cabinet and then determines the energy needed to maintain the interior
ambient temperatures dictated by the OOE test procedure Turiel and Heydari present the
energy consumption figures for a 18 cubic foot top-mounted automatic defrost
refrigeratorfreezer as a baseline case They find that 74 of the total energy is accounted
for by the compressor 11 is for the anti-sweat heaters 10 is for the fans and 5 is
for the defrost heaters for a total of 947 kWhyr Also about 10 of the compressor
energy use is for the removal of internal heat generated by the evaporator fan motor defrost
heater and anti-sweat heaters
Several subsequent simulations were performed each time adding a design option that was
projected to improve efficiency The improvement levels were added cumulatively and
results were given on compressor run time heat leakage rate into the cabinet compressor
5
power demand at the operating point fan motor operating power for the evaporator and
condenser fans anti-sweat heater power and total daily and annual energy consumption
The goal here was to achieve by the last level of improvement the minimum energy
consumption that is technologically feasible One important fmding for all product classes
tested the highest efficiency was obtained by the use of evacuated panels in the planar
walls For example for the top-mounted automatic defrost unit the minimum energy use
was 515 kWyr
Finally an energy usevolume relation was developed from a linear regression obtained
from simulation results The resulting fit was shown as
Energy Use = Cl + C2Adjusted Volume
The constant Cl indicates the direct energy use to remove the cabinet loads associated with
the fan motors and heaters The slope C2 is an indicator of the rate of change ofenergy use
with a change in the adjusted volume This value reflects the rate of cabinet heat gain The
adjusted volume is the volume of the fresh food compartment plus 163 times the volume
of the freezer Turiel and Heydari produced a series of regressions for all of the defined
levels of design improvements allowing easy comparison at a specific adjusted volume
6
3 ONE-DIMENSIONAL WALL AND DOOR LOADS
In this section the overall steady cabinet load is calculated without considering the addition
of edge loading This load qlD is dermed as the heat transfer from the exterior
environment to the interior of the refrigerator under nonnal closed-door operating
conditions through four primary conductive paths (i) fresh food compartment walls (ii)
freezer walls (iii) fresh food door and (iv) freezer door In a later chapter the load due to
edge loading will be examined more closely
31 One-dimensional Heat Transfer Model
The steady conductive heat transfer through the walls of the refrigerator cabinet is
computed using a simple computer program written by Qausing (1983) This program
estimates inside and outside effective heat transfer coefficients using a flat plate natural
convection correlation Using these coefficients and the material properties and dimensions
of the wall insulation the one-dimensional heat transfer through the cabinet walls is
approximated for the fresh food and freezer compartments Figure 31 shows the
resistances and boundary conditions use in the model
Fig 31 Model Used To Calculate One-dimensional Load
7
The model provides flexibility for varying several parameters This allows application to
various types of refrigerator walls and doors Table 31 lists the input and output
parameters for the model The source code of the simulation along with the output for
completed runs are included in Appendix B
Table 31 One-dimensional Model Parameters
Input Parameters
To K (F) Room ambient temperature
Ti K (F) Interior ambient temperature
LiDs m (ft) WalVdoor insUlation thickness
kiDs Wm-K (Btuhr-ft-F) WalVdoor insulation thermal conductivity
A m2 (ft2) Cabinet surface area
Output
beo Wm2K (Btuhr-ft2_F) Exterior convective heat transfer coefficient
bei Wm2K (Btuhr-ft2-F) Interior convective heat transfer coefficient
hro Wm2K (Btuhr-ft2_F) Exterior effective radiative heat transfer coefficient
hri Wm2-K (Btuhr-ft2_F) Interior effective radiative heat transfer coefficient
qlD W (Btuhr) Heat transfer rate through specified section
32 Determination of Effective Heat Transfer Coefficients
The simulation developed automatically estimates the inside and outside effective heat
transfer coefficients This effective value is the sum of the convective and radiative
components which are defined below
The radiative heat transfer coefficients are computed iteratively using eqs (31) and (32)
assuming (i) gray walls at temperatures T wi or Two with emissivities poundi and Eo (ii) black
surroundings at Ti or To and (iii) walls can see surroundings only
(31)
(32)
8
The convective heat transfer coefficients are estimated from a flat plate natural convection
correlation developed by Clausing (1983) In the laminar regime (Ra lt 1()9) the Nusselt
number based on the film temperature is given by Eq (33)
NUf = 052 Ra4 (33)
For the turbulent regime (Ra ~ 109) the Nusselt number becomes
NUf = 009 Raf3 (34)
where in both cases
Tw+T_ Film temperature T f == 2
Lc == Vertical surface characteristic length g == Gravitational acceleration f3 == Thermal expansion coefficient v == Kinematic viscosity Tw == Vertical wall surface temperature T_ == Outsideinside ambient temperature
kf == Air thermal conductivity
The film temperature characteristic length Nusselt number and Rayleigh number will
have different values for the inside surface compared with the outside surface of the
cabinet Therefore the inside and outside convective heat transfer coefficients are
determined separately from eqs (35) and (36)
(35)
- NUfo kfohco - (36)Leo
9
33 Results
The four primary regions analyzed are (i) the fresh food compartment walls (ii) fresh food
door (iii) freezer walls and (iv) the freezer door The values for the input parameters
ltLins kins A) are taken from a full-size unit that is used for the experimental analysis
presented in Chapter 4 The room temperature is used for the model parameter To Also
the fresh food ambient Tee and the freezer ambient Tfz are substituted for Ti when
suitable in order to closely simulate real operating conditions The results are given in
Table 32
Table 32 Results From One-dimensional Load Analysis
Input
Section TooC eF)
Tj degC eF)
Lins m (ft)
kins Wm-K (Btuhr-ft-OF)
A m2 (fi2)
Fresh Food 21 4 0045 0027 242 Walls (698) (392) (0148) (0015) (2605)
Fresh Food 21 4 0040 0040 089 Door (698) (392) (0131) (0023) (958)
Freezer 21 -10 0056 0027 110 Walls (698) (-140) (0184) (0015) (1184)
Freezer 21 -10 0040 0040 034 Door (698) (-140) (0131) (0023) (366)
Output
Section hco Wm2-K cBtuhr-ft2-Fl
hro Wm2-K iJtuhr -ft2-Fgt
hci Wm2-K (Btuhr-ft2-F)
hri Wm2-K 1Btuhr-ft2-F)
qlD W (Btuhr)
Fresh Food 130 544 198 461 209 Walls (23) (96) (35) (81) (713)
Fresh Food 144 542 218 463 117 Door (25) (95) (38) (82) (399)
Freezer 143 542 226 397 143 Walls (25) (95) (39) (70) (488)
Freezer 164 538 259 400 81 Door (29) (94) (46) (70) (276)
herro =687 Wm2 K (121 Btulhr-ft2-OF) Total qlD =550 W herrrr = 670 Wm2 K (118 Btulhr-ft2_0F) (1876 Btuhr)
herrrz = 641 Wm2 K (113 Btulhr-ft2-OF)
The load for our operating conditions is 550 W (1876 Btuhr) Once again this quantity
does not reflect the total cabinet load on the refrigerator cabinet Edge effects are analyzed
in detail in the following chapters Another important result is the values for the effective
10
inside and outside heat transfer coefficients which are simply the sum of the convective
and radiative components The outside coefficient is heffo the fresh food coefficient is
heffff and the freezer coefficient is hefffz These numbers are used whenever film
coefficients are needed for computations
11
4 EXPERIMENT AL ANALYSIS
This section presents an experimental study performed on a full-size household
refrigerator In Chapter 3 we defined the load due to heat transfer through the walls and
doors of the cabinet as qlD The purpose of this experimental analysis is to quantify qwalh
qdoor qmulloff and Qrnullon and Qmisc Three types of tests are performed to accomplish
this task Descriptions of each are presented separately in the sections that follow
41 Temperature Profile Measurements
The refrigerator is instrumented with many thermocouples in various key areas to give
temperatures across the steel skin and to compare and verify the thermopile tests outlined
in the next section The four primary paths along the steel flange that are examined are the
wall-side fresh food door-side fresh food wall-side freezer and the door-side freezer
Five Type T 36 AWG thermocouples are placed along the skin for each path Figure 41
is a detailed drawing of the location of the thermocouples
Wall side TICs Door side TICs with 5 mm spacing with 5 mm spacing
Fig 41 Steel Skin Temperature Profile Thermocouple Placement
The wire leads are oriented so they run perpendicular to the temperature gradient so as to
reduce any effects of conduction along the wire to the bead The temperature data are fed to
the data acquisition system Each channel is a thermocouple input and is scanned at a rate
of 5 times a second The data are smoothed automatically by the software in blocks of 10
12
points for an average temperature every 2 seconds A full description of the data
acquisition and control system is provided in Appendix D
Data are collected for several runs to provide a good base to detennine average values since
the test conditions vary slightly from run to run To get a good measurement of the
temperature profIles along the steel flange the unit is shut off at the beginning of the run
and allowed to drift to quasi-steady conditions The presence of a large amount of thennal
mass (see Appendix C) within the refrigerator provides for a stable interior ambient
temperature during data collection The outer ambient is controlled by the room thennostat
which keeps the laboratory at a constant temperature to within plusmn1degC
Figure 42 is an example plot of a run that gives the temperature profIles along the steel
skin on the wall-side and door-side for the fresh food compartment
193
192
G 191 ~
i 19
middot5 189F
188
Run I iii --0 - Door Profile
~Imiddotmiddotmiddotmiddotmiddotmiddotmiddott 0 Wall Profue
i ~ i - - T =19273 - 001206x i i-- door i If ~
=-r~r==L~r=I ~ I +~~=~~~~~~~~~ middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot
Outdoor Ambient = 210 degC Fresh Food Ambient =48 degC
187-+----+----J------I----+---~
o 5 10 15 20 25
x (mm) 1 in= 254 mm
Fig 42 Steel Skin Temperature Plot for Fresh Food Compartment
The dashed line represents a linear least-squares fit for the door data and the solid line is the
corresponding fit for the cabinet wall data Each data point in the plot represents the
average temperature at that point over a period of time at quasi-steady conditions
Similarly Figure 43 is a plot of the temperature profIles for the freezer
13
186
184
a 182
~
i 18
5 178~
176
174
Run 1 t-- 1 1 --0 - Door Profde
P~P1 0 Wall Profile
- -LLl--=-+--shy- - Tdo = 18606 - O02354x i
or ~
=c==-rc1 1 ltb 1 ~
~~r--r- -r---shy0 5 10 15 20 25
x (mm) 1 in= 2S4mm
Fig 43 Steel Skin Temperature Plot for Freezer
A total of six separate runs were perfonned three for the fresh food compartment and three
for the freezer Plots for the other runs are located in Appendix E
From the figures above for the fresh food compartment the slope on the wall-side is
slightly steeper than the slope on the door-side In fact this trend is seen for all the runs
Therefore the heat conduction along the metal skin into the cabinet along the wall is
somewhat greater than that of the door For the freezer the slopes are nearly equal hence
the heat conduction along the wall skin and the door skin are nearly the same
42 Thermopile Testing
Another simple but important test is the use of a thennopile to measure the average
temperature difference at various locations on the steel flange regions of the unit Figure
44 is a schematic of the thennopile test set-up The thennopile is constructed from 36
AWG copperconstantan thennocouple wire
14
-
CopperConstan$t Junctions 285 mPt
IOmm
10mmThermopile
IOmm
Digital Multimeter
1 in= 254mm
Fig 44 Thermopile Test Apparatus
Five junctions are used for the fresh food compartment and three for the freezer The
junctions are mounted 10 mm (039 in) apart from one another along the steel skin beneath
the door seal Figure 45 is a detailed drawing of the lateral location of the thermopile
junctions
15
1 in =254 mm
Fig 45 Thermopile Placement
The thennopile provides an average temperature difference across the junctions The
output voltage must frrst be divided by the number of pairs of junctions and then translated
into a temperature difference using a referencing chart for the thennocouple wire Table
41 is a summary of the results from these tests The output voltages are read accurately to
within plusmn0002 mV The raw data and data reduction procedure are given in Appendix E
Table 41 Thermopile Output
Test Conditions Fresh Food aT Freezer aT TodegC
(OF) TffoC
(OF) Tfzoc
(OF) aTwallff degC
(Of) aTdoorffoc
(OFgt aTwallfzoC
(Of) aTdoorfzoC
(OFgt
1 210 (698)
48 (406)
-88 (162)
026 (047)
024 (043)
037 (067)
041 (074)
2 210 (698)
37 (387)
-87 (163)
027 (049)
026 (047)
038 (068)
040 (072)
3 208 (694)
37 (387)
-93 (153)
027 (049)
026 (047)
038 (068)
040 ( 072)
Average Values 209 (696)
40 (392)
-90 (158)
0267 (0481)
0253 (0455)
0377 (0679)
0403 (0725)
43 Thermocouple Drag Testing
One final technique applied is thennocouple drag testing This is a more qualitative method
to supply insight into what exactly is happening when the compressor is pumping wann
16
refrigerant through the anti-sweat tube that lines the perimeter of the cabinet aperture The
main objective of this test is not to give accurate temperature proftle infonnation but
instead to detennine the placement of the condenser tube This is needed as an input for
the numerical simulation of this region The reason that the temperature are not accurate is
the fact that the thermocouple is being dragged across a surface where good thermal contact
may not occur and significant energy may be generated Figure 46 is a schematic of the
apparatus used for drag testing
Power Supply
Data Acquisition System
Outer Metal Skin
Potentiometer
Inner Plastic Skin
Condenser Tube
Fig 46 Thermocouple Drag Test Apparatus
This device is quite simple yet very effective The type T 36 AWG thennocouple begins
at the interior boundary of the steel skin beneath the seal on the wall-side of the cabinet
The potentiometer is turned by hand moving the thennocouple oqtward along the skin
The temperature and location are stored simultaneously this way The thennocouple is kept
17
pressed against the steel flange by the seal The linear translation of the thennocouple is a
function of the output voltage Voutbull
s = 2mllT Vout (41)Yin
r =radius of potentiometer post =30 mm (012 in)
nT = total number of turns of potentiometer = 10
Vin = input voltage = 05 V
Vout = output voltage
Drag tests are run on the wall steel skin for both the fresh food compartment and the
freezer Runs are perfonned at four separate times the first being when the compressor
turns on Figure 47 is a plot of the drag proflles across the wall-side skin in the fresh food
compartment Figure 48 is a plot of the profiles in the freezer compartment The same
trends are generally seen for both regions The freezer profiles are simply shifted down in
temperature values as expected The temperature peak seems to move through time to
settle near the center of the flange region under the seal
31
30
29
G
i 28~
27
26~
25
24
23
e
Ji ~ i i i 1middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotlmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddoti~~
---l- Time 4
o Time 2 rr
i
0 5 10 15 20 x (mm)
Fig 47 Drag Profiles (Fresh Food)
18
26~--------+---------~-------4--------~
i ~
Time 1 24
22
20
18
16~~------+---------~-------4--------~
4 __
~~Time3
middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot_middotmiddot_middotmiddotimiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot
Outer Seal Edge o
o 5 10 15 20
x (mm)
Fig 48 Drag Profiles (Freezer)
44 Experimental Determination of qwall and qdoor
The results from the temperature profile and thennopile testing are used to detennine qwall
and qdoor according to the following defmitions
qwall = qwallff + qwallfz (42)
(43)
Where qwal1ff = heat conduction along wall-side fresh food compartment steel flange
qwallfz = heat conduction along wall-side freezer compartment steel flange
qdoorff = heat conduction along door-side fresh food compartment steel flange
qdoorfz = heat conduction along door-side freezer compartment steel flange
The trends derived from the fixed profiles exhibit generally good agreement with the
temperature differences seen by the thennopile For the fresh food compartment the
thennopile displays a slightly larger AT than what is seen in the profiles and both give a
19
slightly larger temperature difference for the wall-side compared with the door-side For
the freezer the temperature differences match closely on the wall-side however the doorshy
side AT is shown to be somewhat less than the wall-side AT for the fIXed thennocouple
measurements where the opposite is seen from the thennopile The worst discrepancy is
on the order of 10 and is probably due to the fact that the thennopile gives an average temperature difference at several vertical locations on the wall whereas the other method is
at one vertical location only
Since the thennopile produces an average temperature difference across the steel skin its
output is used to detennine the heat flux into the cabinet The refrigerator casing is being
used as a heat meter Thus the flux along the skin in the fresh food compartment on the
wall-side is
kmiddot ATwallffqwallff = m (44)
Ax
The load qwallJf is Eq (44) multiplied by the cross sectional area This area is the
thickness of the steel casing multiplied by the perimeter that is exposed to the room
ambient This perimeter varies for each of the two paths that comprise qwall and the two
paths that comprise qdoor The other cabinet loads are computed in a similar way and are
given in Table 42 The details of these values are given in Appendix E
Table 42 Experimental Determination of qwall and qdoor
Section Load W (BtuIhr)
qwallJf 28 (96)
qwallJz 21 (72)
qwall 49 (168)
qdoorff 33 (112)
qdoorJz 33
1112)
qdoor 66 (224)
20
45 Experimental Determination of qmulloff
The region that lies between the fresh food compartment and the freezer is called the
mullion The front portion of the mullion is covered by a thin steel face plate to provide a
suitable interface for the door seal magnets In this section the load due to heat conduction
along the mullion steel skin into the freezer and fresh food compartment is detennined
based on the experimental data
The heat transfer rate qmulloff is sum of two parts The first component is the heat
conduction along the steel plate into the fresh food compartment and the second is the
conduction into the freezer
qmulloff = qmulloffff + qmullofffz (45)
Figure 49 schematically illustrates paths of these two components
FREEZER
FRESH FOOD COMPARTMENT
Fig 49 Heat Flow Paths in Mullion
21
Ten 36 A WG type T thennocouples are mounted from top to bottom across the steel face
plate Figure 410 shows the cross section of the plate and the location and numbering of
the thennocouples
FREEZER
1bennocouplesSteel Face (5 mm spacing from
Plate bottom edge)
Freezer Gasket
Fresh Food Gasket
10 50
FRESH FOOD COMPARTMENT
1 in =254 mm
Fig 410 Mullion Face Plate Cross Section
Data are gathered from the ten thennocouples when the unit is shut off and allowed to drift
to a quasi-steady ambient temperature A total of five runs were perfonned Figure 411 is
a sample plot of the quasi-steady temperature profile All other plots are contained in
AppendixE
22
116
Run 1 I 115 ICcIIIII114 iii t ~mull~ =12~7 - 00~654xa
~ 113
rrfIIJ~~If112i 5 )mullfz 1= 1081~ + OOdl25X 111111 ~
11 oo+-t--t-iH-+-lo-shyiii i i Room Ambient = 2184 degc
109 middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1middot Fresh Ambient = 381 OC
108
1 10
I I I I I Freezer Ambient =-832 degc
2 3 4 5 6 7 8 9
TIC
Fig 411 Mullion Temperature Profile
The plot also shows two linear equations These represent linear fits to each side of the
peak temperature at TIC 7 The slopes (shown in degCmm) are used to detennine the heat
conduction to each compartment by eqs (46) and (47)
lmulloffff = km A (aT) (46)ax offff
qmul)offfz = km AIll) (47)ax offfz
The cross sectional area is the product of the face plate thickness (10 mm 0039 in) and
the length of the mullion (717 mm 2825 in) The average slopes from all five runs are
used to detennine qmulloffff and qroullofffz The results are given in Table 43
23
Table 43 Experimental Results from Mullion Analysis
Load W (Btuhr)
09qmullofUz (31)
07qmulloffff (24)
16qmuIlorr (55)
46 Experimental Determination of qmullon
In this section the load due to heat conduction along the mullion steel skin into the freezer
and fresh food compartment when an anti-sweat heater is on is experimentally determined
The test unit is equipped with an electric anti-sweat heater to eliminate condensation in the
mullion region The heater is installed on the back side of the plate and may be switched on
manually when needed It is a wire resistor type rated at 10 watts
The heat transfer rate qmullon is composed of two parts The first component is the heat
conduction along the steel plate into the fresh food compartment and the second is the
conduction into the freezer similar to ~ul1off
qmuIlon = ~ullonff + qmuIlonfz (48)
The location of the wire heater and the heat transfer paths are shown in Figure 412
24
FREEZER
qmullonfz
qmullonff
FRESH FOOD COMPARTMENT
Fig 412 Electric Heater Location
A series of tests are perfonned while the heater is on and the refrigerator is cycling
nonnally Three runs are done at each of three separate locations along the mullion
laterally (i) LEFT dermed as 180 mm (71 in) from the left-hand side of the unit (ii)
RIGHT 180 mm (71 in) from the right-hand side of the unit (iii) CENTER at center of
the mullion Figure 413 is a plot of the temperature profile across the face plate when the
heater is on for a specific test run The plots for all other runs are provided in Appendix E
The plot shows two profiles These represent the upper and lower limits as the unit cycles
The upper limit occurs just before the compressor turns on while the lower limit is at the
point in time just before the compressor shuts off At all times in between the profile
oscillates between the two limits maintaining nearly the same shape Once again a linear
fit is applied to the data on the fresh food side and the freezer side
25
30 iii imiddot iii i
29
28
27
Run 1
T mu
ill~~ 11 f = 26707 + 010776x Tmu11ff = 3128 - 00793x
Z +_ a 26~
I ~
middotmiddotmiddotbull-middotbullimiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotimiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotimiddotmiddotmiddotimiddotmiddot
24
25
e 23~ =H-T+H~i=i=
iimiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotimiddotmiddot T 11 ff = 27435 - 009504x 22 Tmullfz =21865 + 01l786x I m~ iii
21 -lmiddotmiddotmiddotmiddotmiddotmiddotmiddot-tmiddot Upper Limlt 0
20 middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotjmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotimiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddott 0 Lower Limit
19
0 1 2 3 4 5 6 7 8 9 10
TIC I
Fig 413 Mullion Temperature Profile With Heater On (Center)
Heat fluxes are computed identically to the method in Section 45 using the average slopes
from all nine runs The minimum value occurs just before to compressor turns on while
the maximum value occurs just before the compressor shuts off during normal cycling
The load is averaged over the cycle time which is approximately 50 for the test unit and
laboratory conditions The results are given in Table 44
Table 44 Experimental Results from Heater Analysis
Lower Profile Average W
(BtuIhr)
Upper Profile Average W
ffituhr)
qmullonfz 73
(249) 53
(181)
qmullonff 23 (78)
26 (89)
96 (32 7)
79 (270)
qmullon 88
300)
26
47 Determination of Qmisc
The load qoisc is comprised of three main parts The first is the load due to the evaporator
fan motor The fan that moves cool air in the cabinet also adds a thennalload Fans of this
type in use range from 8 - 16 watts The fan of our test unit is rated at 92 watts This
value must be integrated over the cycle time The cycle time for the unit is approximately
50 for the test conditions Thus the value of qfanave is 46 watts
The load qdefrostave is not determined experimentally Instead an estimate is obtained from
a similar study done by Turiel and Heydari (1988) This value is 5 watts which is an
average of the defrost heater input over the defrost cycle The defrost cycle can range from
10 - 12 hours of compressor run-time
The fmalload qcompave is detennined by measuring the cabinet surface temperature at the
region surrounding the compressor and computing the heat transfer locally The value is
found to be 2 watts Table 45 summarizes the results
Table 45 Miscellaneous Loads
Load W CBtuhr)
46 qfanave (15middotU
50 qdefrostave _07Ql
20 qcompave (68)
116 Qmisc (395)
27
s NUMERICAL SIMULATION
In this chapter a two-dimensional numerical model which is used to simulate the steadyshy
state heat transfer in the wall near the door seal is discussed The results from the model
include a computation of qwallff qwallfz and the complete temperature distribution across
the section The model is also used to estimate the additional cabinet load due to the
presence of an anti-sweat condenser tube embedded beneath the outer casing that runs
along the perimeter of the unit A separate model is presented which is used to simulate the
two-dimensional heat transfer across the door seal cross section The results are used to
determine qseal
51 Wall Model
A finite-difference technique is used to approximate the steady-state temperature
distribution in the wall section The technique is applied to solve the governing steady
two-dimensional heat conduction equation (assuming constant conductivity with no
generation)
(51)
Equation (52) is the basic fmite-difference representation of the conduction equation in a
homogeneous medium of constant conductivity with no heat generation (White 1988) In
Appendix F a complete list of all the model difference equations is provided
2(1+(3)Tij = (3Tij+l + Ti+lj+(3Tij-l + (3Ti-lj (52)
where (3 = (llxlly)2
28
Figure 51 is a sketch of the model representation of the refrigerator wall at the door seal region The dimensions shown are flexible parameters in the model The model allows for
slight changes in the geometry as well as changes in mesh size in both x and y directions
However the mesh size must remain uniform across the section
s5 s6
sl
Fig 51 Wall Heat Conduction Model Sketch
For each of N unknown nodal temperatures N simultaneous linear algebraic equations are obtained for N unknowns If N is large as is the case for this simulation an iterative
technique is preferred to solve the system ofequations A Fortran program has been
written to carry out the finite-difference iteration A copy of the code is given in Appendix
F A simple Guass-Seidel technique is employed for the differencing iteration At each
iteration an energy balance is done for the entire section In theory this balance should be
29
zero (heat entering) = (heat leaving) The iteration is continued until the difference
between heat entering and heat leaving is equal to 1 of the total heat entering the section
Table 51 defines the input parameters for the simulation
Table 51 Wall Simulation Input
Code Parameter Definition
To C (F) Exterior surrounding ambient temperature
Ti C (F) Interior ambient temperature
lan Wm-K (Btuhr-ft-F) Steel skin conductivity
kp Wm-K (Btuhr-ft-F) Plastic skin conductivity
kins Wm-K (Btuhr-ft-F) Wall insulation conductivity
heffo Wm2-K (Btuhr-ft2-F) Outside effective heat transfer coefficient
hefti Wm2-K (Btuhr-ft2-F) Inside effective heat transfer coefficient
dm mm (in) Steel skin thickness
dp mm (in) Plastic skin thickness
dx mm (in) Mesh size x direction
dy mm (in) Meshsizeydirection
sl mm (in) Wall width
s2 mm (in) Wall length
b mm (in) Effective Perimeter
s3 mm (in) Seal indentation
s4 mm (in) Seal width
s5 mm (in) Depth of steel skin into cabinet along seal boundary
s6 mm (in) Width of plastic skin along seal boundary
The model assumes that the boundary that lies along the door seal is adiabatic This allows
the separation of the wall section from the rest of the geometry in this region The seal and
door can then be treated separately later A simple calculation is done to validate this
assumption
30
Steel Skin (Refrigerator wall)
Seal (k = 02 Wm-K)
Fig 52 Non-adiabatic Door Seal
A 2 degC temperature difference AT is imposed across the seal This is a slight overshy
estimate based on the experimental data An estimate of the conductive heat flux is
determined from Eq (53)
ATqerror=k- (53) Ax
qrror =02 Wm-C o~Cm =20 Wm2
The heat flux ql for the fresh food compartment is determined in Appendix E to be 14418
Wm2 Therefore qerror represents approximately 13 of the total flux Hence this
term is neglected in this study
Two other possible sources of error are associated with the fmite-difference technique itself
(Ozisik 1980) The fIrSt is called truncation error and arises from the discretization of the
second-order derivative in the steady conduction equation The second is referred to as the
round-offerror which is due to the fact that numerical calculations are carried out only to a
finite number of decimal places Repeated solution with smaller increments shows that the
truncation error is negligible The precision of the energy balance is evidence that the
round-off errors are negligible
31
S2 Wall Simulation to Determine qwall
The finite-difference model is used to detennine the wall-side heat transfer along the steel
skin However more valuable information is yielded from the simulation The nodal
temperature distribution is detennined which gives insight into the direction and magnitude
of heat fluxes throughout the section The fresh food compartment and the freezer are both
simulated to detennine qwallff and qwallJz respectively Table 52 is the list of the values
used for the model input parameters for both cases
Table S2
Code Parameter
To C eF)
Ti C eF)
kIn Wm-K (Btuhr-ft-F)
kp Wm-K (Btuhr-ft-F)
kins Wm-K (Btulhr-ft-F)
heffo Wm2-K (Btuhr-ft2_F)
heffi Wm2-K (Btuhr-ft2-F)
dm mm (in)
dp mm (in)
dx mm (in)
dy mm (in)
sl mm (in)
s2 mm (in)
b mm (in)
s3 mm (in)
s4 mm (in)
s5 mm (in)
s6 mm (in)
Input Values
Fresh Food 210 (698) 40
(392) 540 (312) 015 (009) 0027 0015t 687 (121) 670 (118) 065
(0026) 25
(0098) 225
(0088) 25
(0098) 450
(1772) 2000 (7874) 2960
(11653) 225
(0088) 2025 (0797) 225
(0886) 2025 (0797)
32
Freezer 210 (698) -10
(140) 540middot (312) 015 (009) 0027 (0015) 687 (121) 641 (113) 065
(0026) 25
(0098) 28
(0088) 25
Jo098) 540
(2125) 2000 (7874) 1580
(6220) 28
(0110) 196
JO772) 224
(088t) 288
(1134)
The output from the simulation includes the entire nodal temperature field heat fluxes at
each node along the centerline heat fluxes from node to node along the steel skin beneath
the door seal and the value for qwallff and qwallcz These heat transfer values and the
nodal temperature distribution are listed in Appendix F
The quantities qwallff and qwallcz are determined by computing the heat fluxes from node to node along the centerline of the section subtracting the one-dimensional flux and then
multiplying by the cross sectional area for that node and summing to give the total heat
transfer rate The primary results are shown in Table 53
Table 53 Wall Simulation Results
Section
The temperature distributions are shown in the following two figures Figure 53 shows
the temperature contour for the fresh food results Figure 54 is the same plot for the
freezer results
Since the geometry of the refrigerator door is similar to that of the wall along the edges the
heat leakage to the food compartments along the door flange can be approximated as being
roughly the same as qwall This approximation of qdoor is a good means of estimating the
two prime contributors to the edge loss for various different refrigerators which may have
slightly different geometries as well as different material properties
33
i
3875
3625
TemplaquogtC)
-e
11111
20
18
16 3375
g 3125 14 -5 2875 ~ 122625 ~
2375~ 102125~
1875 8
1625
1375 6
1125
875 4
625
375
SteeVPlastic Liner Interface
Fig 53 Fresh Food Wall Temperature Distribution
34
i 4875
4625
4375
4125
3875
3625
3375 -
3125e g 2875
2625 ~ 2375 ~ 2125c (I)
1875 ~ 1625
1375
1125
875
625
375
125
Fig 54 Freezer Wall Temperature Distribution
Temp(OC)
20
15
10
5
0
-5
-10
35
53 Wall Edge Simulation to Determine qtube
The wall simulation is modified to include a constant temperature node placed beneath the
steel flange to represent the presence of an anti-sweat condenser tube The simulation is
perfonned for the specific conditions that are typical of the test unit as well as a range of
lateral tube locations For the test refrigerator the tube is located as shown in Figure 55
and is at 35degC (95 OJlt)
Outer Steel Skin
14625 mm 1
Inner Plastic Liner
Fig 55 Tube Location for Simulation
The quantity qtube is detennined by taking the fluxes along the vertical line to the left of
the tube subtracting the one-dimensional flux and then multiplying by the cross sectional
area for that node and summing to give the total heat transfer rate Again the fresh food
compartment and the freezer must be simulated separately to produce a total governed by
Eq (54)
(54)
Program output for the fresh food and freezer simulations is given in Appendix F Table
54 summarizes the results from the model
Table 54 Wall With Condenser Tube Simulation Results
Section Load W iBtubrl
qtubeff 46
(157)
qtubefz 28 (96)
qtube 74 (253)
qtube8ve (ave for 50 cycle time)
37 (126)
36
-I i c IJ
~
r 4875
4625
4375
4125
3875
3625
3375
3125
2875
2625
2375
2125
1875
1625
1375
1125
875
625
375
125
TempfC)
SteeVPlastic Liner Interface
35
30
25
20
15
10
5
Fig 56 Fresh Food Wall Temperature Distribution Including Warm Anti-sweat Tube
37
TempfC)4875
4625
4375
4125
3875
3625
3375 - 31258
2875g 2625fo 2375
3 2125 d vI 1875
~ 1625
1375
1125
875
625
375
125
SteeVPlastic Liner Interface
Fig 57 Freezer Wall Temperature Distribution Including Warm Anti-sweat Tube
38
40
30
20
10
0
-10
The heat fluxes at each node along the vertical line to the left of the tube are also computed
by the simulation This value quantifies the amount of heat that is moving toward the outer
boundary and is used to determine the percentage of heat entering the cabinet For the test
refrigerator this value is 18 for the fresh food compartment and 24 for the freezer
Several more simulation runs were done to find the effect of lateral placement of the tube on
the overall heat transfer and the percentage of heat entering Figure 58 and Figure 59
show the trends that are found
-~ a tUbe ~middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotlmiddotmiddotmiddot=middotmiddot=pmiddotmiddotmiddot=middot-1- =1
middot middot middoti middot middotmiddotmiddotmiddotmiddotmiddotmiddotmiddot bull middotmiddotmiddot i middotmiddotmiddotmiddot middotmiddot middotmiddot ~ middotmiddot
middotmiddotrmiddot-rmiddot 0 lwbeff middotlmiddotmiddot~middot Gmiddottmiddotmiddot9middotlmiddot
i i -0- lwbe i middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotimiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddot fz tmiddotEimiddotmiddot ~G- -~ -q- -
0 5 10 15 20 25 x(mm)
Fig 58 Load Due to Condenser Tube for Various Tube Placements
8
~ - 7
50
a 6
~ 5
~ en 4 ~
pound ~ 3
2
- 26
~ a 24
middots bO
pound 22c ~
~ 20
a = 18sect ~
16 0 5 10 15 20 25
x (mm)
Fig 59 Percentage of Heat Entering Cabinet for Various Tube Placements
39
54 Door Seal Simulation to Determine qseal
Another model is developed for the two-dimensional heat transfer through the door seal
This model is very similar to the one created for the wall section Once again a fIniteshy
difference technique is utilized to detennine the temperature distribution at steady-state
conditions Even though the cross sectional geometry of the seal is simplifIed to a square
with a hollow square with a centrally located cavity no closed-form solution can be
applied Therefore a simulation is needed
The fInite-difference representation of the two-dimensional steady Eq (55) using central
differencing is given by Ozisik (1980)
Ti-lj - 2Tij + Ti+lj + Tij-l - 2Tij + Tij+l = 0 (55) Ax2 Ay2
For this model a square mesh is applied reducing Eq (55) to
Ti-lj + Ti+lj + Tij-l + Tij+l - 4Tij = 0 (56)
x
Fig S10 Seal Simulation Mesh Layout
40
The nodes along the vertical surfaces at x=O and x=20 are subject to the convective
boundary conditions and governed by Eq (57) and Eq (58) respectively
2~xheffol 2~heffo2Ti+lj + Tij-l + Tij+l - (4 + k TiJ = - k To (57)
seal seal
2~heffffl 2~heffff2Ti-lj + Tij-l + TiJ+l - (4 + kseal Tij = - kseal Tff (58)
The nodes along the top and bottom outside surfaces are held at the prescribed temperature
profIles which are detennined from experimental data (see Section 41) The interior nodes
are subject to radiant e~change among themselves and conduction through what is assumed
to be stagnant air A closer look at the model of the hollow interior of the seal is shown in
Figure 511
Fig 511 Seal Cavity Mesh Details
Each interior node corresponds to a single gray surface with assumed emissivity of 09
Viewfactors for all surfaces are computed automatically before the iteration begins For
each iteration the effect of radiation within the enclosure is taken into account by updating
surface radiosities Jij Thus for nodes on interior surfaces an extra tenn is added to the
governing difference equation (Eb is the blackbody radiation)
41
~(J - Eb )1-pound IJ lj
A code written in Fortran is used to perfonn Guass-Seidel iteration of the difference
equations to compute the temperature distribution at mesh nodes (Code listing in Appendix
F) Once again convergence is based on an energy balance applied to the entire section
The iteration is continued until the difference between heat entering and heat leaving is
equal to 01 of the total heat entering the section Table 55 lists the input parameters
used in the model The fresh food compartment and the freezer compartment are simulated
separately
Table 55 Seal Simulation Input
Code Parameter Fresh Food Freezer
Number of nodes along outside edge 20 20
Number of nodes along inside edge 6 6 1 1Lx = fly mm (in) (0039) (0039)
210 210Outdoor ambient temperature degC (oF) (698) (698) 150 105Indoor local ambient temperature degC COF) 590J j509)
Outdoor heat transfer coefficient W m2-K 687 687 (121) (121)(Btuhr-ft2-F)
Indoor heat transfer coefficient Wm2-K 670 641 (118) (113)(Btuhr-ft2-F)
Gasket interior surface emissivity 09 09 03 03Gasket conductivity Wm-K (Btuhr-ft-F) (0173) (0173)
Wall-side Temperature Boundary 1905 - 1977x 1813 - 3475x Condition degC Door-side Temperature Boundary 1913 - 1384x 1852 - 2341x Condition degC
42
The load results are summarized in Table 56 below The program output is listed in
AppendixF
Table 56 Seal Simulation Results
Load W Section (BtuIhr)
10 Qsealff (34)
ljQsealfz (Sn
25qseal (85)
The steady-state temperature distribution is shown in the figures below Figure 512 is the
fresh food simulation and Figure 512 is the freezer simulation The direction of the heat
flow through the section is easily seen from these plots
43
Wall-side Boundary Temperature (C)
~~
I 20
195
i 19t 0
8 ~ 1859 -- ~
isis ~ ampJ gtshy 18 ~
11 ~ S ~ 175~
~ 17
165
x(mm)
Door-side Boundary
Fig 512 Seal Temperature Distribution (Fresh Food)
44
Wall-side Boundary Temperature (C)
Ii 19
185
18i f IQ 5 IQ
175-is-is I s 17j ~
5e 0C= 165
~ ~ 16
155
x(mm)
Door-side Boundary
Fig 513 Seal Temperature Distribution (Freezer)
45
6 DISCUSSION OF RESULTS
The heat transfer values detennined from the experimental analysis and the numerical
simulations are the various components that embody the cabinet load on the refrigerator It
is important to separate cabinet loads from system loads The system load can be thought
of as the total electrical energy consumption of the unit It has four basic components (i)
the compressor (ii) fans (iii) anti-sweat heaters and (iv) defrost heaters The first two
components the compressor and fans are the cost of removing heat from the cabinet This
amount of heat is equal to the cabinet load divided by the COP of the system The typical
energy consumption is shown schematically in Figure 61
System Load (Energy Consumption)
Defrost Heater (averaged over time
cycles every 10-12 hours of compressorrurt-time)
TuneCycle
Fig 61 Refrigerator System Load Graph
In a study done by Turiel and Heydari (1988) the compressor and fans accounted for 84
of the total system load for an 180 cubic foot top-mounted refrigerator Staley (1992)
found this value to be 86 for a similar unit Both of these studies used system analysis to
determine these numbers The energy consumption of the components were monitored
during operation The energy consumption of our test refrigerator can be determined in a
reverse manner from the cabinet load data If a COP of 1 is assumed the test refrigerator
46
compressor and fans accounts for 86 of the energy consumption to cool the cabinet This
compares favorably with the fmdings of Turiel and Heydari (1988) and Staley (1992)
Figure 62 is a schematic of the cabinet loads One possible load that is not included in the
figure is the heat input associated with the defrost drain tube that runs through the back
wall However this term is probably small relative to the other contributors
Cabinet Load
qseal qdoor
qwall
qmullon
qdefrostave
Fig 62 Cabinet Loads Graph
All the loads are determined in this study from either experimental measurements
numerical simulations or both Most of the loads are quasi-steady that is they do not
fluctuate significantly over the cycle time of the refrigerator There are four loads shown in
Figure 61 that are cyclical in nature The three loads that appear only while the
compressor is running are qcomp qfarb and qtube Also the refrigerator is subjected to a
load every time ice build-up is removed by the defrost heaters This load is averaged over
its own cycle time and shown in the graph as qdefrostave
47
61 Comparison of Simulation Results with Experimental nata
The majority of the cabinet loads are detennined from experimental data with the exception
of qseal and qtube The wall and door flange loads aremiddot also found from the numerical
simulation (see Chapter 5) The two-dimensional model detennines the wall-side heat
transfer along the steel skin into the food compartments No model is available to directly
detennine the heat transfer on the door-side However since the flange geometry on the
door-side is similar to the wall the value for qwall is considered to be a good estimate for
qdoor Table 61 gives these values determined from experimental measurements and the
simulation
Table 61 Comparison of Simulation and Experimental Values for qwall and qdoor
Experimental Result W Simulation Result W (BtuIhr) (BtuIhr)
qwallff 28 (96)
28 (96)
qwallz 21 (72)
27 (92)
qwall 49 (168)
55 (188)
ldoorff 33
(112) 28 (96)
qdoorfz 33
(112) 27 (92)
qdoor 66 (224)
55 (188)
The model predicts qwall to within 57 of the experimental value The agreement of the
estimate of qdoor with the experimental value is within 90
Some of the shortcomings in the model used in this investigation are
(i) Only the wall is modeled Ideally the entire region should be considered including the
door and seal (see Figure 11)
(ii) The flange geometry is simplified The steel casing skin in the flange region may bend
in more complex ways Also the plastic liner varies in thickness near the door seal
(iii) The mesh must be unifonn There is no means to vary how fme the mesh can be The
ideal situation would be to have a fine mesh near the edges and a course mesh far from the
seal
48
62 Mullion Analysis
The single largest edg~ load is found in the mullion section (329 of qedge and 94 of
qtol) This load is due to the electric anti-sweat heater installed on the backside of the face
plate The heater is rated at 10 watts and approximately 88 of that input enters the
interior of the cabinet as a thennalload This is probably due to the small surface area
exposed to the room and the low amount of convective heat transfer in the channel between
the fresh food and freezer doors With the heater on 88 watts is measured enter the food
chambers With the heater off only 16 watts enters the interior The addition of the
heater increases the mullion load 55 times Generally it is not necessary to use the
mullion heater at all times However for the test environment the heater nearly all the time
to eliminate sweating under the laboratory conditions
63 Seal Analysis
The heat conduction directly through the seal accounts for the smallest portion of the edge
loss (94 ofqedge and 27 of qtol) The numerical model to detennine these values uses
a simplified representation of the complex cross sectional geometry of an actual door seal
The various air pockets are reduced to a single hollow void There is no experimental data
to verify the model However the numbers and trends resulting from the simulation are
reasonable
64 Anti-sweat Condenser Tube Analysis
Thennocouple drag tests were perfonned to give insight into the nature of the temperature
profIles at the wall steel flange with the presence of an anti-sweat condenser tube The wall
heat transfer simulation model was modified to include the effect of this tube The heat
conduction to the interior increased by 76 at the wall flange region The amount of
additional loading due to the tube depends on several parameters location of the tube
temperature of the circulating refrigerant and local wall geometry Although the model is
flexible enough to handle vari01~S temperatures and limited geometrical changes only the
influence of tube position was investigated As the tube is moved towards the interior the
load increases For the test refrigerator about 20 of the heat flow was directed to the
interior compartments primarily along the steel skin
49
6S Overall Cabinet Load
The overall cabinet load is defined as a sum of three parts
(61)
The edge load is
qedge = qwall + qdoor + Qseal + Qrnullon + qtubeave (62)
where
qwall
qtubeave
heat input due to the conduction along the wall steel flange
heat input due to the conduction along the door steel flange
heat conduction directly through the door seal
heat input due to conduction in the mullion region with the additional input from anti-sweat heater
heat input due to cabinet anti-sweat condenser tube averaged over the cycle time
heat input due to cabinet anti-sweat condenser tube
qmulloff heat input due to conduction in the mullion region electric heater off
The terms of Qrnisc are defined as
qmisc = qfanave + qdefrostave + qcompave (63)
where
qfanave heat input from the evaporator fan averaged over the cycle time
qdefrostave heat input from the defrost heaters averaged over defrost cycle time
qcompave heat input from elevated exterior walls near the running compressor
Table 62 presents the overall cabinet load analysis results
50
Table 62 Overall Cabinet Loads
Load W Load Btuhr Total
qlD 550 1876 591
qedge 265 903 285
Qwall 49155 167 188 53
Qdoor 66155 2251 188 71
Qseal 25 85 27
Qmullon 88 300 94
Qtubl ngt 37 126 40
qmisc 116 395 124
Qfanave 46 157 49
Qdefrost ave 50 170 54
qcomoave 20 68 21
qtot 931 3174 100
Simulation Results
All loads are detennined experimentally with the exception oflsea1 and qtubeave The
values for qwall and qdoor are detennined from both experimental data and numerical
simulations Edge loss per unit length along fresh food perimeter is 29 Wm (30 Btuhrshy
ft) the loss per unit length along the freezer perimeter is 44 Wm (46 Btuhr-ft) and the
loss along the mullion section is 123 Wm (128 Btuhr-ft) with the heater on and 22 Wm
(23 Btuhr-ft) with anti-sweat heater off
The largest single load is the one-dimensional conduction through the walls and doors
The edge load comprises 285 of the total a significant portion The largest edge load is
due to the electric anti-sweat heater that is installed in the mullion section The smallest
edge load is due to the heat conduction through the fresh food and freezer door seals The
losses at the wall-side and door-side flange regions account for 53 and 71 of the total
load respectively These could be considered together since the pathway of heat transfer is
very similar If that were the case the sum of qwall and qdoor would be the second largest
contributor to the overall cabinet load The influence of an anti-sweat condenser tube is
reflected in the value of qtubeave Although this additional load is larger than qwall it must
be integrated over the refrigeration cycle timewhich is 50 of the cycle time for the test
unit The tube boosts the heat transfer along the wall flange by 76
51
To round out the cabinet load three miscellaneous loads are considered The evaporator
fan motor produces a heat load within the cabinet which is considered to be equal to the
power rating of the fan The automatic defrost feature is another thermal load that is
cyclical appearing about every ten to twelve hours of compressor runtime The fmalload
is due to the elevated exterior skin temperature near the compressor when it is running All
three of these loads are averaged over their cycle times for comparison with other quasishy
steady loads As a total qmisc represents 124 of the overall cabinet load
Opportunities to decrease the one-dimensionalload are available The emphasis has been to
develop super-insulations to be installed in the refrigerators Some being considered are
vacuum panels aerogels and vacuum packed powder insulations The disadvantages of
this improvement lies within the need to develop a cost-effective technique for fabricating
and installing such technologies compatible with high-volume manufacturing Also edge
losses and panel connection losses must be minimized due to the difficulty in making a
panel the size of refrigerator interiors Reliability of the seal and perfonnance of the outer
envelope need to be ensured over a long period of time ie the expected life of the
product
The possibilities of reducing the loads along the edge of the refrigerator aperture are
somewhat less apparent One method of reducing quasi-steady heat conduction along wall
and door flanges is to raise the inside cabinet wall temperature by minimizing interior film
surface heat transfer coefficients This could be accomplished by the use of low-emissivity
surfaces on the interior walls or on sections nearest the edges The need for an anti-sweat
device for the perimeter is also eliminated supplying a two-fold savings by reducing the
cabinet ioad and the system energy consumption The need for an electric mullion heater
might also be done away with by the same means The drawback again would be to make
such modifications acceptable and cost-effective for manufacture
The remaining miscellaneous loads provide some chance for improvement If the
efficiency of the fans is increased the energy use of the refrigerator can be reduced The
option of moving the fan motor outside the cabinet leads to other problems The motor
shaft must pierce the wall providing another path for heat leakage Also frost built-up on
the shaft would be a costly and difficult problem to eliminate If the compressor and
condenser were located near the top of the refrigerator they can operate more efficiently
Heat can be more readily convected away eliminating the need for the condenser fan
(Turiel and Heydari 1988) Frost fonnation in the freezer varies significantly depending
52
on the ambient conditions and the freezer usage The defrost cycle could be made more
energy efficient with the addition of adaptive controls All of these improvements would
require redesign of the product and the manufacturing process This is a very expensive
alternative which would need to be justified by the associated energy savings
53
7 SUMMARY OF CONCLUSIONS
The following is a list of the important findings produced from this study
(i) The edge loading accounts for a significant portion of the total cabinet load For the
test unit used in this study an 18 cubic foot top-mount refrigerator this load was
approximately 30 of the total load The load includes losses along the wall and door
flanges conduction through the door seal mullion loading with an electric anti-sweat
heater on and additional thennal input from an anti-sweat perimeter condenser tube
(ii) The presence of an electric anti-sweat mullion heater boosts the mullion loading by
a factor of approximately 5
(iii) The presence of an anti-sweat condenser tube around the perimeter of the refrigerator
increases the wall flange load by approximately 75
(iv) The presence of the door air damt reduces the temperature difference across the door
seal to 35 of the temperature difference between the interior and exterior
environments
(v) The hypothetical elimination of the additional load due to the electric anti-sweat
mullion heater reduces the edge loading to approximately 22 of the total cabinet
load
(vi) The hypothetical elimination of the load due to the anti-sweat condenser tube reduces
the edge loading to approximately 25 of the total cabinet load Ifboth anti-sweat
devices were not needed the edge loading would be further reduced to only 17 of
the total
(vii) During the course of this investigation it was concluded that the experimental and
numerical methods developed are applicable to most refrigeratorfreezers that are
produced today
t The portion of the door liner that extends into the cabinet along the wall
54
REFERENCES
Braswell A 1988 Impact of CFC Regulations on the Air Conditioning and Refrigeration Industry International Jow-nal ofRefrigeration Vol 11 No6 p 385
Cabot Corporation 1987 CAB-O-SIL Fumed Silica Properties and Functions Tuscola n pp 12-15
Clausing A M 1983 Natural Convection Correlations for Vertical Surfaces Including Influences of Variable Properties ASME Jow-nal ofHeat Transfer Vol 105 No 1 pp 138-143
Incropera FP and Dewitt DP 1985 Fundamentals ofHeat and Mass Transfer Second Edition John Wiley and Sons New York
Ingersoll LR Zobel OJ and Ingersoll AC 1954 Heat Conduction with Engineering and Geological Applications McGraw-Hill Book Company New York
Little AD Inc 1982 Refrigerator and Freezer Computer Model Users Guide Cambridge Massachusettes
Micropore International Ltd Microtherm Thermal Insulation Worcestershire England Section 1
Nix GH Lowery GW Vachon RI and Tanger GE 1967 Direct Determination of Thermal Diffusivity and Conductivity with a Refined Line-Source Technique Progress in Astronautics and Aeronautics (Vol 20) Thermophysics ofSpacecraft an Planetary Bodies Academic Press New York pp 865-878
Nix GH Vachon RI Lowery GW and McCurry TA 1968 The Line-Source Method Procedure and Iterative Scheme for Combined Determination of Conductivity and Diffusivity Thermal Conductivity Proceeding of8th Conference
Ozisik MN 1980 Heat Conduction Wiley-Interscience Publishing New York pp 486-487
Staley D 1992 Personal Communication Graduate Research Assistant University of Illinois Urbana
Turiel I Heydari A 1988 Analysis of Design Options to Improve the Efficiency of Refrigerator-Freezers and Freezers ASH RAE Transactions Vol 94 Part 2
Van der Held EFM and Van Drunen FG 1949 Physika Vol 15 No 10 p 865
White PM 1988 Heat and Mass TranSer Addison-Wesley Publishing Reading Mass pp 145-160
55
APPENDIX A FUMED SILICA INVESTIGATION
A ~ 1 Introduction
Fumed silica is a micro-porous powder comprised of submicron particles of amorphous
silica bonded together in a cellular structure Several grades of silica are available offering
a selection ofdifferent grain sizes and chemical treatments Fumed silica is commonly used
to provide thickening thixotropy suspension and other related properties in liquid
systems In dry systems it is used to promote free flow frictionizing and anti-blocking
properties Thus it is a versatile additive in materials such as inks coatings adhesives~
and silicon rubber (Cabot Corporation 1987)
The thermal insulating properties of this material have been somewhat less widely applied
however fumed silica as an insulation displays some interesting properties Fumed silica
insulations are commercially available and have become a more popular material for certain
specific applications In this section the results of an investigation of the thermal
properties of one type of fumed silica is presented
A2 Thermal Properties
As an insulator fumed silica uses the microporous principle to reduce thermal conduction
to the theoretically lowest possible levels (Micropore International Ltd 1988) Most
conventional insulations rely upon voids normally occupied bj alt aS the meanS ot
minimizing heat transfer through the material Therefore it is important to maintain these
voids for maximum insulation Fumed silica is comprised of tiny spheres with diameters
of the same order of magnitude as the mean free path of the molecules in the air
Therefore when these spheres are packed closely together gaseous conduction and
convection are minimized The cell size is sufficiently small to keep convective currents
from forming and to trap gas molecules to rebound elastically thereby not imparting their
energy to slower moving molecules In addition solid conduction is minimized by the fact
that silica is a material with intrinsically low thermal conductivity These unique properties
make fumed silica an attraCtive alternative to conventional insulations
56
A3 Experimental Method
Thennal conductivity and thennal diffusivity are the properties detennined from our
experimental study Many methods exist for establishing the thennal properties of a given
substance Both steady-state and transient procedures are available The hot-wire method
is a the transient procedure used in this study
The practical form of the hot-wire method is given by Van derHeldand Van Dronen
(1949) who used it to detennine conductivities of liquids Nix et al (1967) elaborated to
give a method for the simultaneous detennination of both thennal conductivity and thennal
diffusivity Therefore it is possible to detennine both conductivity and diffusivity by
passing a known amount ofcmrent through a heater wire embedded in the test material and
recording the temperature at a point on the wire and at a fixed point from the wire over the
period of the test From the temperature history of the point contiguous to the hot-wire the
conductivity can be detennined directly From the temperature history of the point at a
fixed distance from the hot-wire the diffusivity may be computed Both procedures are
outlined in the following section
A4 Theory
The temperature at any point in an infinite solid containing a line heat source of constantshy
rate is a function of the position time from initiation the thennal conductivity of the
material and the magnitude of the source This is shown mathematically by Ingersoll et aI
(1954) The cylindrical temperature field is expressed as
T=~l- exp-x2) dx (Al)21tk x
II
In series fonn
(A2)T=~[-amp-lnp+L-L+L_ ]21tk 2 21 4middot2 63
57
where
q = Heat input per unit length of wire [W1m]
k = Thennal conductivity of the material [Wm-K]
a = Thennal diffusivity of the material [m2s]
t = Elapsed time from heat liberation [s]
r = Radial distance from line-source [m]
Ce = Eulers constant (05772157 )
The temperature change between two times tl and t2 is accurate to better than one percent if
the value of ~ is less than 016 for a point very close to the line-source
(A3)
Equation (A3) is used in this case to detennine the thennal conductivity since the
diffusivity a and the radial distance T no longer appear in the relation Therefore
knowing the temperature at two different times during the test gives the conductivity
directly given that the value of ~ remains small This is achieved by choosing a point very
near if not contiguous to the hot-wire itself In our study a graphical method is used to
detennine the conductivity If the temperature versus the natural logarithm of the time is
plotted a straight line should be seen whose slope is equal to q4nk
Once the conductivity of the material is detennined the diffusivity can be found by the
method proposed by Nix et aI (1968) The temperature at a fixed and known distance
from the hot-wire must be monitored over the time period of the test Now since ~ gt 016
the diffusivity does not drop out of Equation (A2) Rewriting Equation (A3) as
(A4)
where
~2 ~4 ~6 ]r(~)= [ -~-ln~+---+-- (A5) 2 211 4middot2 6middot3
58
therefore (A6)
Using the temperature at the fixed location as an input Equation (A6) can be solved iteratively by means of Newton-Raphson technique to find the parameter ~ and thereby
yielding the thermal diffusivity a
AS Test Apparatus
Figure A1 is a sketch of the test apparatus used to collect thermal property data This
device provides a wide range of silica densities for packed tests Each half of the apparatus
is packed separately to the same density and then pressed together sandwiching the heater
wirethermocouple assembly between them
Remove bottom plate and press together with right half
Insert heater wirethermocouple assembl)
Remove bottom plate and press together with left half
Compact both halves to same density
Fig AI Fumed Silica Test Apparatus
Prior to loading the unpacked silica into the test cylinders the mass is carefully recorded
Each test cylinder has graduated marks to allow the volume of the sample to be computed
The density is then computed from the measured mass and volume At higher densities it
59
is sometimes necessary to load and compact several times Figure A2 is a schematic of the
heater wirethermocouple assembly and the entire test facility
Switch
Ammeter
Power Source
Cylindrical Test Section
Thermocouple for Conductivity
Data Acquisition System
Thermocouple for Diffusivity
Fig A2 Fumed Silica Test Facility Schematic
The heater wire used for all tests is 30 A WG nichrome wire with a nominal resistance of 2214 Wm Both thermocouples are type T 36 A WG Once the test sample is in place
the switch is closed allowing cUITent to pass through the heater wire The heat input per
unit length of the wire is determined from
(A7)
where q = Heat input per unit length of wire [Wm]
I = The input cUITent [Amps]
R = Heater wire resistance per unit length [Wm]
60
Knowing the heat input per unit length the temperature contiguous to the heater wire and
the temperature at a fixed distance from the heater wire over the duration of the test eqs
(A3) and (A6) can be solved This yields the conductivity and diffusivity respectively
A6 Results
All results presented in this section are from tests petfonned with a material sample donated
by Cabot Corporations Cab-O-Sil Division The silica is an untreated sample EH-5 with
a bulk density of 25 Ibsft3 and a nominal particle diameter of 70 angstroms Several tests
are petfonned at various densities The thermal conductivity is determined graphically as described above while the diffusivity is determined using a Fortran code to pe~orm the
Newton-Raphson iteration also outlined in Section A4
A total of seven different bulk densities are tested Each test consists of three runs at three
different power levels The temperature history is recorded for both thermocouples
Figure A3 is a plot of the temperature for the duration of a typical test for unpacked silica
70~--~----+----r----~-----~----+----r
10001
middot middot middot o 05 Ampsmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddot o 04 Ampsi ~ i
I i I I i oo~ct 60 IIJatr-T50
1 LL~40
1 ~ 1 010 1 ltgtom
JPi i30 i 0I1 o 03 Amps 1 I I
20~--~----+----r----~-----~----+----r
-10 o 10 20 30 40 50 60 70 Time (sec)
Fig A3 Time vs Temperature for Unpacked Run
61
To graphically detennine the thennal conductivity the temperatme data must be plotted
against the natural logarithm of time Figure A4 gives this plot along with the equations
that represent linear curve-fits to the straight portion of each curve
70~----~--------+------+--------~----~----~--------+-----~
60 ~ =l-LL-~--o T ~ 86839 ~ 1376 ~(t) I
50 ---f--H-deg--tfjtshy ~ T =11108 + 97346 m(t)
40 IT_oroJ~-
30 middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotImiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotsectmiddotmiddotmiddotmiddotmiddotImiddotmiddotmiddotmiddotmiddotmiddotmiddot~middotmiddotmiddotmiddot109~~Q9 T= 18431~ + 493 ~(t) 0
~ e i i i
20~----~--------+------+--------~---------~~----+------r
05 1 15 2 25 3 35 4 45 In (time)
Fig A4 Natural Log Time vs Temperature for Unpacked Run
All three curves should yield the same conductivity for the sample The conductivity is
detennined from the following relation
k= 12R (A8)4n(slope)
Table AI gives the average conductivity for each density level This is the average for the
three input cmrents used These results are also shown graphically in Figure A5
62
Table AI A verage Fumed Silica Conductivity for Various Bulk Densities
est
1
2
3
4
5
6
7
0024
0023
0022 -~ ct 0021
~ e 002
~
0019
0018
0017
i
~i
I I I I Imiddotmiddotmiddot_middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotimiddot_middotmiddot middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotimiddot-middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot
1i111
~ ~ iii
_I_1_1_1
I I I I I middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot middotmiddotmiddotmiddotmiddotmiddotmiddotfmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddot -r-t-o-rldegoo---shy
25 3 35 4 45 5 55
Density (lbsff)
Fig AS Conductivity vs Bulk Density
From the temperature data collected from the second thennocouple the thennal diffusivity
is computed (see Section A4) This thennocouple lies 3 mm (0118 in) from the heater
63
wire The output from the diffusivity iteration is provided in Table A2 A graphical
representation is given in Figure A6
Table A2 Average Fumed Silica Diffusivity for Various Bulk Densities
Test
Average Diffusivity m2s (ft2Jhr)
1 210 x 10-7 (000813)
2 166 x 10-7 (000643)
3 159 x 10-7 (000616)
4 155 x 10-7 (000600)
5 153 x 10-7 (000592)
6 No Data Available
7 151 x 10-7 (000585)
00085 -+----+-----f----+----+----+--_+_
I
middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1 ~0008
I I I I ~
I middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotfmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot Tmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot ~ 00075
~-shyf i ~ ~ ~ i ++middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotfmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot0007 i iii
~ rn ~ ~ i i~
(jj bullbullbullbullbullbull1bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullJLbullbullbullbullbullbullbullbullbullbullj ~ 00065o ~ middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot0006
I I I 00055 -+----+-----f----+----+----f--_+_
25 3 35 4 45 5 55
Density (lbsff)
Fig AS Diffusivity vs Bulk Density
64
A7 Conclusions
The primary conclusion from this experimental study is the fact that the thennal insulating
properties of fumed silica powder increase as the bulk density of the material increases
Although this study presents a limited range of density values the trends that were
expected are seen to be true The conductivity values are expected to reach and even
surpass those of CFC-blown foams that are used in household refrigerators Further
testing is needed to provide data that supports this expectation In addition testing in this
study was strictly limited to a single variety of silica This particular type of silica is not
necessarily the best candidate for thermal insulation applications Silica powders are by
nature hydroscopic This affinity for water has adverse effects on its thermal insulating
properties However silica powders are now produced with a special treatment which
transforms the material into a hydrophobic material Therefore if these new materials
maintain the thermal properties and density trends of the hydroscopic type they become
even more preferred insulators Once again data needs to be obtained to support this
notion Fumed silica offers a competitive alternative to the existing CFC-blown foams
without the obvious environmental drawbacks It is completely inert recyclable and
reusable It also competes well when comparing cost values CFC-blown foams are
between 003 - 007 $ft2_R-Value whereas fumed silica powder are between 005 -025
$ft2-R-Value The discrepancies are close enough to merit true consideration
AS Thermal Diffusivity Newton-Raphson Iteration Source Code
program difsivty implicit none double precision condqtime(lOO)temp(lOO)guessradiusalpha
+ dif(lOO)sumavedifgcurrentmasslengthpi + density integer nikrun OPEN (2file=Oiffusivityoutlposition=rewind) OPEN (3file=Oiffusivityinposition=rewind) OPEN (4file=Oiffusivityout2position=rewind)
print Enter input current in amps readcurrent printEnter calculated conductivity in Wm K readcond print Enter thermocouple distance in meters readradius print Enter mass of sample in grams readmass print Enter compacted length of sample in em readlength print Enter number of timetemperature data points
65
c
readn 5 print enter initial quess for beta
readquess c
pi=31415927 q=currentcurrent2214 density=(mass1000)laquopi4)(003844)(lenqth100raquo
c c check to see if converqence will occur c print Enter data point l c print (time and temp with a blank separatinq the two) c readtime(1)temp(1) c call diffus(condqtime(1)temp(1)quessradiusalphaq) c printinitial q=q c if (abs(q) qt 05) then c qoto5 c endif c
do 10 i=1n read(3) time(i)temp(i)
10 continue c
print print Input Current= current print write(2) Input Current= current write (2 )
c sum=OO do 20 k=1n call diffus(condqtime(k)temp(k)quessradiusalphaq) print Diffusivity for data pointk =alpha write(2) Diffusivity for data pointk =alpha write(4) alpha dif(k)=alpha sum=sum+dif(k)
20 continue c
avedif=sumn c
print print print INPUT print Conductivity=cond Wm K print Heater Input=q Wm print Thermocouple Distance=radius m print- print OUTPUT print Sample Density=density kqm3 print Averaqe Diffusivity=avedifmiddot m2s
c write(2) write(2) INPUT write(2) Conductivity=cond Wm K write(2) Heater Input=q Wm write(2) Thermocouple Distance=radius m write (2 ) write(2) OUTPUT write(2) Sample Density=density kqm3 write(2) Averaqe Diffusivity=avedif m2s
c c
pause stop
66
end
subroutine diffus(condqtimetempguessradiusalphag) implicit none double precision condqtimetempbeta(100)radius
+ f1f2f1pf2ptempf2tempf2pggppialphaCe + signfactol integer jkmn
c Ce=5772157 pi=31415927 beta (1) =guess tol=l j=l
c c begin Newton-Raphson iteration to find beta and ultimately alpha c
while (tol gt 0001) c print betaj =beta(j)
f1=-Ce20 - log(beta(j)) flp=-l Obeta (j) f2=00 f2p=00
c c start loop to compute the summations for f2 and f2 prime
do 10 k=2162 m=k2
c this loop gives the factorial for the kth term fac=10 do 5 n=lm
fac=facn 5 continue
sign=(-1)laquok+2)2) tempf2=laquobeta(j)k)sign)(kfac) tempf2p=laquobeta(j)(k-1))sign)fac f2=f2+tempf2 f2p=f2p+tempf2p
10 continue
c c compute the value of G and G which are both functions of beta c these will be used to update beta in the Newton-Raphson iteration c where beta(n+1)= beta(n)- GG
g=laquo20picondtemp)q)-(f1+f2) gp=- (flp+f2p)
c print g=g c here we check to see if the convergence criterion suggested c by Nix is met for the initial beta chosen if not we must jump out of loop c if (j eq 1) then c if (abs(g) qt 05) then c printconvergence not satisfied c printtry a s~aller guess for beta c return c endif c endif c c update the value of beta and compute a tolerance value c that will be used to check for convergence
beta(j+1)=beta(j)-(ggp) tol=abs(beta(j+1)-beta(j))
67
j=j+1 c protect against infinite looping
if (j eq 100) then goto 101
endif repeat
c c if the iteration converges then compute the value for diffusivity
alpha=(10(40timeraquo(radiusbeta(jraquo2
c c
101 return
68
APPENDIX B ONE-DIMENSIONAL SIMULATION SOURCE CODE AND OUTPUT
B1 Source Code
CPROGRAM FrigWall--Steady-State Heat Conduction with Convective and CRadiative Heat Transfer from interior and exterior surfaces C Programmed by AM CLAUSING
LOGICAL SI DIMENSION RA(2)XNU(2)R(2)H(2)HR(2)TF(2)TW(2)DT(2) COMMON AXLWXLC(2)HC(2)T(2)XKWBETANMAXSIE(2)SIGMA
CDetermine- direction of output read and print input data NCASE=l
1 CALL DATAIN(NCASEIUOUT) NCASE=NCASE+1 QOLD=O TW(1)=T(1)+1(T(2)-T(1raquo TW(2)=T(2)-1(T(2)-T(1raquo
CCalculate wall resistance RW=XLWXKWA DO 3 N=lNMAX DO S J=12
CCalculate the radiative equivalent heat transfer coefficients HR(J)=SIGMAE(J)(T(J)2+TW(J)2)(T(J)+TW(Jraquo
C Calculate the film temperatures TF(J)=(T(J)+TW(Jraquo2
CCalculate the convective heat transfer coefficients CALL GASPT(lTF(J)RHOXMUXKCPGRBPRIER) DT(J)=ABS(TW(J)-T(Jraquo RA(J)=PRGRBXLC(J)3DT(J) IF(RA(J) LT1E9) THEN
XNU(J)=0S2RA(J)2S ELSE
XNU(J)=09RA(J) 3333 ENDIF H(J)=XNU(J)XKXLC(J) IF(HC(J) NE O) H(J)=HC(J)
CCalculate surface resistances R(J)=l(H(J)+HR(JraquoA
S CONTINUE CCalc~late total resistance heat flow rate and surface temperatures
RT=R(1)+R(2)+RW Q=(T(2)-T(1raquoRT TW(l)=T(l)+QR(l) TW(2)=T(2)-QR(2)
CCheck for convergence If solution has converged exit loop ERRQ=ABS(Q-QOLD)100Q QOLD=Q IF(ERRQLT OS) GOTO 7
3 CONTINUE 7 WRITE (IUOUT 101) Q ERRQ (H (J) HR (J) RA (J) XNU (J) TW (J) DT (J) R (J) RT
2 J=l2) 101 FORMAT( Q =F61 W10XERRQ =FS2 T12 hconvT22hradT33
2 RaT44NuTS2 TsurT62 DeltaTT72RRtotT10 [Wm2-KjT20 2 [Wm2-KjTS3 [KjT63 [Kj InsideF72F92E133F91 2 F101F91F113 OutsideF62F92E133F91F101F91F113) DO 9 J=l2 IF(HC(J) NE bull O) WRITE (IUOUT 103) J
9 CONTINUE 103 FORMAT( NOTE hconv(I1 ) was specified not calculated)
GOTO 1 END
69
C SUBROUTINE DATAIN(NCASEIUOUT) LOGICAL SI COMMON AXLWXLC(2)HC(2)T(2)XKWBETANMAXSIE(2)SIGMA DATA AXLWXKWXLCHCTENMAXSIGMA2990360245315 2 20277297 959510567E-8
CDefinition of NAM NAMELIST NAMAXLWXKWXLCHCETNMAXBETASI CHARACTER FNAME60CDATE9CTIME8 PARAMETER (IUIN=7)
CIF First Case Open Files Write Program Description and Date IF (NCASEEQ 1) THEN
WRITE (6 100) 100 FORMAT( TYPE NAME OF INPUT DATA FILE)
READ( (A) ) FNAME COpen input and output files
OPEN (7FILE=FNAME) REWIND 7
C OPEN (10FILE=Plots-FNAME) C WRITE(6122) Plots-FNAME C122 FORMAT( COMMA DELIMITED PLOTTING FILE IS A)
WRITE(6118) 118 FORMAT (T10 DIRECT OUTPUT TOT20 SCREENT36 Type 6
2 T20 OUTPUT FILET36 Type 8T20 PRINTERT36 Type 9) READ() IUOUT IF(IUOUTEQ8) THEN OPEN (8FILE=Answers-FNAME) WRITE(6120) Answers-FNAME
120 FORMAT( OUTPUT WILL BE WRITTEN IN FILE A) ENDIF CALL DATE(CDATE) CALL TIME(CTIME)
CWrite Program Description and Date WRITE(IUOUT102)CDATECTIME
102 FORMAT( Program FrigWallT60 Date A10 Version 8 August 1991T60 2 Time A9 Programmed by AMClausing) ENDIF
CRead and Write Input Data READ(IUINNAMEND=999) WRITE (IUOUT 104) NCASETXLCEXLWXKWA
104 FORMAT ( CASE NUMBER 12 2 Ambient Temperatures IK] InsideF616X OutsideF61 2 Characteristic Lengths 1m] InsideF626X OutsideF62 2 Surface Emissivities8X InsideF626XOutsideF62 Wall
Thickness 2 F63 mT27 ConductivityF63 Wm-K2x AreaF52 m2) RETURN
999 WRITE (IUOUT 199) 199 FORMAT ( ALL INPUT DATA HAS BEEN PROCESSED) 991 CLOSE(10)
IF(IUOUTEQ 8) CLOSE(8) STOP END
C SUBROUTINE GASPT(NGASTRHOXMUXKCPGRBPRIER)
C PROGRAMMED BY A M CLAUSING VERSION APRIL 1982 C PROPERTIES OF GASES IN SI UNITS(TGTO) OR ENGLISH UNITS(TLT O) C FUNCTIONAL REPRESENTATIONS USED ARE OF THE FORM Y=ATB C ARRAYS A AND B CONTAIN THE RESPECTIVE CONSTANTS C INPUT C NGAS - NGAS=l IS AIR NGAS=2 IS NITROGEN C T ---- ABSOLUTE TEMP (K) OR NEGATIVE OF ABSOLUTE TEMP (R) C OUTPUT C RHO -- DENSITY (KGM3) OR (LBMFT3)
70
C XMU -- VISCOSITY (KGM-S) OR (LBMFT-S) C XK --- THERMAL CONDUCTIVITY (WM-K) OR (BTUHR-FT-R) C CP --- SPECIFIC HEAT (JKG-K) OR (BTULBM-R) C GRB -- GBETAXNU2 (1M3-K) OR (1FT3-R) C PR --- PRANDTL NUMBER (DIMENSIONLESS) C IER -- ERROR PARAMETER C INFORMATIVE ERRORS C IER=l --- GAS NUMBER DOES NOT EXIST GAS IS ASSUMED TO BE AIR C IER=2 --- TEMPERATURE OUT OF RANGE OF PROPERTY SUBROUTINE C RESTRICTIONS C NGAS -- MUST BE l(AIR) OR 2 (NITROGEN) C T ----- T MUST LIE BETWEEN 150K AND 2100K FOR AIR AND BETWEEN C 83K AND 450K FOR NITROGEN RANGES ARE SPECIFIED WITH ARRAY R C
DIMENSION A(152)B(152)R(32) DATA A36411764E-61423E-399084178E20123 235064914E-62494E-329944985E195930 3 432491E-81239E-415534379E201137 4351618E-6221E-31031408E2084130 DATA B-1005814913800316-4639-09685 2 -999642981521962-4284023930 3 -10469389466-079-5102-0872 4 -10058058 834500239-4636-0265230 DATA R150400210083160450 IER=O IFlaquoNGASGTO) AND(NGASLT3raquo GO TO 1 IER=l NGAS=l
1 1=1 TP=T IF(TLT bullbull O) TP=-T18 IFlaquoTPLTR(lNGASraquo OR (TPGTR(3NGASraquo) IER=2 IF(TPGTR(2NGASraquoI=7 RHO=A(INGAS)TPB(INGAS) XMU=A(I+1NGAS)TPB(I+1NGAS) XK=A(I+2NGAS)TPB(I+2NGAS) CP=A(I+3NGAS)TPB(I+3NGAS) GRB=A(I+4NGAS)TPB(I+4NGAS) PR=A(I+5NGAS)TPB(I+5NGAS) IF(TGT O)RETURN RHO=RHO1602 XMU=XMUl 488 XK=XKl 731 CP=CP4187 GRB=GRB6357 RETURN END
B2 Output
Program FrigWal1 Version 8 August 1991 Programmed by AMClausing
Date Time
05-MAR-92 200227
CASE NUMBER 1 - Fresh Food Walls
Ambient Temperatures IK] Inside 2770 Outside 2940 Characteristic Lengths 1m] Inside 030 Outside 150 Surface Emissivities Inside 095 Outside 095
71
Wall Thickness 0045 m Conductivity 0027 Wm-K Area 242 m2
Q = 209 W ERRQ = 002
hconv [Wm2-K]
Inside 1 98 Outside 130
hrad [Wm2-K] 461 544
Ra
0488E+07 0459E+09
Nu
244 761
Tsur [K]
2783 2927
DeltaT [K] 13 13
RRtot
0077 0075
CASE NUMBER 2 - Fresh Food Door
Ambient Temperatures [K] Inside 2770 Outside 2940 Characteristic Lengths [m] Inside 030 Outside 150 Surface Emissivities Inside 095 Outside 095 Wall Thickness 0040 m Conductivity 0040 Wm-K Area 089 m2
Q = 117 W ERRQ = 001
hconv [Wm2-K]
Inside 218 Outside 144
hrad [Wm2-K] 463 542
Ra
0714E+07 0690E+09
Nu
269 843
Tsur [K]
2789 2921
DeltaT [K]
19 19
RRtot
0114 0113
CASE NUMBER 3 - Freezer Walls
Ambient Temperatures [K] Inside Characteristic Lengths [m] Inside Surface Emissivities Inside
2630 030 095
Wall Thickness 0056 m Conductivity 0027
Outside Outside Outside
2940 150 095
Wm-K Area 110 m2
Q = 14 3 W ERRQ = 003
hconv [Wm2-K]
Inside 226 Outside 143
hrad [Wm2-K] 397 542
Ra
0990E+07 0684E+09
Nu
292 841
Tsur [K]
2651 2921
DeltaT [K]
21 19
RRtot
0067 0061
CASE NUMBER 4 - Freezer Door
Ambient Temperatures [K] Inside 2630 Outside 2940 Characteristic Lengths [m] Inside 030 Outside 150 Surface Emissivities Inside 095 Outside 095 Wall Thickness 0040 m Conductivity 0040 Wm-K Area 034 m2
Q = 81 W ERRQ 002
hconv [Wm2-K]
Inside 259 Outside 1 64
hrad [Wm2-K] 400 538
Ra
0169E+08 0124E+10
Nu
333 967
Tsur [K]
2666 2906
DeltaT [K] 36 34
RRtot
0117 0110
72
__ ___
APPENDIX C TEST REFRIGERATOR DESCRIPTION
The test refrigerator is a White-Westinghouse model RT193MCWO 186 cubic foot
capacity top-mounted unit It is equipped with full automatic defrost The cycle time for
this unit is approximately 50 The unit also has two anti-sweat devices An electric
heater is located in the mullion region to prevent frosting between the freezer and the fresh
food compartments Also a condenser tube runs around the entire outside perimeter of the
unit embedded beneath the steel all flange Figure C1 illustrates these features
~1-- 0787 m (31)__
~ r_----------------------
1581 m
Fig CI Location of Anti-sweat Devices and Overall Dimensions of Test Refrigerator
73
Under test conditions the refrigerator and freezer are filled with milk containers full of
water These containers provide sufficient thennal mass to minimize temperature
fluctuations dming experimental runs Twenty gallons are present in the fresh food
compartment and 6 gallons are in the freezer
Figures C2 through C5 give the detailed dimensions of the fresh food compartment and
the freezer All dimensions are in millimeters and are obtained directly from the unit
Dimensions are estimated to be accurate to within plusmn 3 mm
697
762
1
305
717
Fig C2 Fresh Food Compartment Interior Dimensions
74
1127
Fig C3 Fresh Food Door
75
675
381
Fig C4 Freezer Interior Dimensions
432
Fig CS Freezer Door
76
APPENDIX D DATA ACQUISITION AND CONTROL SYSTEM
Corresponding with the construction of the experimental apparatus was the purchase and
assembly of a data acquisition and control system The system itself was designed to meet
the needs of a variety of experiments and is therefore a very flexible system
The system consists of six DC power supplies a data acquisition chassis a computer a
rack ofdigital relays and a variety of analog and digital inputs and outputs A data
acquisition and control software package orchestrates the interactions between these
components and regulates outgoing signals as well as providing data storage
External signals enter the system through a Keithley 500P data acquisition chassis These
signals consist of voltage and current measurements from the power supplies as well as
thermocouple voltages At present a total of ninety-six thermocouple inputs are available
with an optimal resolution of +0012 degrees C The addition of more thermocouple input
boards could expand the capability to 128 inputs Also special boards can be installed to
allow strain gauge thermistor digital or other standard data acquisition functions The
Keithley chassis can contain a total of nine interface boards and its l~bit AID conversion
allows for very high resolution
The six DC power supplies consist of two Hewlett Packard and four Sorensens with a
combined power of 7560 watts The Sorensens are rated at 0-150 volts at a maximum of
12 amps while the Hewlett Packards produce 0-60 volts at a maximum of 3 amps All of
the power supplies are computer-controlled however the Sorensens may be operated
manually ifdesired Voltage measurements from the power supplies are fed into the
Keithley acquisition chassis and are then routed to the computer A voltage from the
computer is buffered and fed into the control circuits of the power supplies This voltage
completes the loop and controls the output voltage of the power supplies The software is
responsible for reading the output voltage of the power supplies comparing it with the
intended setpoint and adjusting the control voltage as needed This arrangement allows the
user to vary the output voltage of the power supplies from within a program Computershy
controlled safety relays are in place to disconnect the power supplies should they stray too
far from the intended voltage setpoint Fig D1 displays the system
77
Thermocouple and Voltage Inputs
r
Computer Data Acquisition Chasis Intaface
00 Voltage and 1 r Current
Measurement
Computer
I I
Analog Control Signal
Digital Oulput Signals 5 6
Power Supply 4 Relay Rack
Power Supply 3 00000001 Power Supply 2
Buffered Analog100000001 Power Supply 1 Control Signal
1 2 3 4 5 6 - I
I00 00 )0 po po po
Ir Digital Outputs
Analog Outputs
Fig DI Data Acquisition and Control System
78
APPENDIX E EXPERIMENTAL RAW DATA AND PLOTS
E1 Temperature Profile Plots From Fixed Thermocouples
In this appendix the remaining tests for the fixed thennocouple testing presented in Section
41 are provided Figures E1 and E2 give the results from the fresh food compartment
and Figures E3 and E4 give the results from the freezer Notice the outdoor and interior
ambient temperatures are not the same as the two tests presented in Section 41
191
Run 2 ttl ~ i i
middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot
middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot-imiddotmiddot
TWall
middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotlmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot
-
Outdoor Ambient =210 degC Fresh Food Ambient =375 degC
-] _ Door ProfUe i -il- 0 Wall Profile
i 19
$-- - Tdo = 19078 - 001326x
l~l ~~i 189 i i a m
0 i -m-
i 188 middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot
187 ~ middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot 5 = 18989 - O02024x 1
F 186
~bullbullbullbullbullbullbullmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot185 i i
184 0 5 10 15 20 25
x (mm)
Fig E1 Steel Skin Temperature Plot for Fresh Food Compartment (Run 2)
79
191
19
189
a ~
i 188
187
5F
186
185
184 0
Run 3 I --D - Door Profile
middotmiddotmiddotmiddotmiddotmiddotmiddotmiddot-middotmiddotmiddotmiddot~middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotimiddotmiddot-middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddot 0 Wall Profile
i - i - - Tdo =19053 - 001384x or
=c-=r=-~-= 1 11=
~ n - 189S 001998 --t-shy-~~-
5 10 15 20 25
x (mm)
Fig E2 Steel Skin Temperature Plot for Fresh Food Compartment
186
184
182
- ~- 18
178
~ 176
174
172 0
(Run 3)
Run 2 l --0 - Door Profile
middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot~middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotdrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotf 0 Wall Profile - 1- - middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot--m
- - T =18544 - 002398x i - i door rb
~i
i bullbullbulli _ bull imiddot
~ I TWall =18182 - 003542x tmiddotmiddotmiddotmiddot middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotlmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot
~ n~l l
5 10 15 20 25
x (mm)
Fig E3 Steel Skin Temperature Plot for Freezer (Run 2)
80
--a 0
I5F
186
184
182
18
178
176
174
172
Run 3 I --0 - Door Profile
middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotCmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotl 0 ~a1l Profile
ttl __ OJ 1 1 middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotfmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotlmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot -shy - Td = 18411 - 002272x ibullbullbullbullbullbullbull-bullbullbullbullbullbullbullbullbulli
oor ~
rp bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbull bull 11_1
I I middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotimiddotmiddotmiddotmiddot middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotImiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot
~ _l
Outdoor Ambient =208 degc Freezer Ambient = -93 degc
0 5 10 15 20 25
x (mm)
Fig E4 Steel Skin Temperature Plot for Freezer (Run 3)
E2 Thermopile Data Reduction
The data from the thennopile tests consist of an output voltage (mV) measured with a
Keithley multimeter which has a resolution of 1 m V The procedure required to translate
this voltage into a temperature difference follows
1 Read the output voltage in millivolts
2 Detennine the average skin temperature from fixed thennocouple data
3 Use the reference table and the average skin temperature to determine the conversion factor in Vrc
4 Convert to temperature difference as follows
1T = ____o_utpu_t_vo_l_tag-e___
ofjunctions x conversion factor
81
Table EI Thermopile Raw Data
ffOutput fzOutput ff Ave Skin Temp fz Ave Skin Temp mV mV CC CC
Roo wall door wall door wall door wall door
1 0052 0048 0045 0050 189 191 177 183
2 0054 0052 0046 0048 187 189 176 182
3 0056 0053 0046 0051 186 188 175 181 ff Conv Factor fz Conv Factor ff AT fzAT
Ilvrc Ilvre CC CC
Roo wall door wall door wall door wall door
1 40165 40181 40067 40116 026 024 037 041
2 40148 40165 40058 40107 027 026 038 040
3 40140 40157 40050 40099 027 026 038 040
Average Temperature Difference 0267 0377 0253 0403
from Thermocouple Reference Tables Based on the IPTS-68 US Dept of Commerce
E3 Experimental Determination of qwall and qdoor Details
The four heat fluxes are calculated using
-k M (El)q - m Ax
For 05 carbon cold rolled steel km =540 Wm K (312 Btuhr-ft-OF) Also Ax = OOlm (039 in) for all computations
0267degC 2 qwallff = 54 Wm-K 001 m = 14418 Wm
_ 0377 degc _ 2 qwallfz - 54 Wm-K 001 m - 20358 Wm
0~3~ 2 qdoorff =54 Wm-K 001 m =13662 Wm
82
0403degC 2 qdoorfz = 54 Wm-K 001 m = 21762 Wm
Compute the heat transfer rate according to Equation (B2)
q =qA=qhP (B2)
Where A is the cross sectional area of the steel casing that is perpendicular to the direction
of heat flow The area is the product of the steel skin thickness b and the total perimeter of
the compartment opening which is exposed to the room environment P Perimeter
definitions
Pwallff = llm + 076m +llm = 296 m
roJ D Pwallfz =O4lm + 076m + O4lm =l58 m
I ] I ~I Pdoorf( = llm + 076m + llm + 076m = 372 m
Pdoorfz =076m + O4lm + 076m + 041m =234 m
83
qwallff =(14418 Wm2)(65e-4 m)(296 m) =277 W
qwallfz =(20358 Wm2)(65e-4 m)(158 m) =209 W
qdoorff =(13662 Wm2)(65e-4 m)(372 m) =330 W
qdoorfz =(21762 Wm2)(65e-4 m)(234 m) =331 W
E4 Temperature Profile Plots From Mullion Data (Heater oro
The following plots are from the remaining runs for the mullion analysis presented in
Section 45 All data is taken from the exact center of the mullion
131
13 middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot-tmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotjmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotlmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot9middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotlmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot6middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddot T 11 f =12383 + 0019929x iii mu z
129 ~ middotImiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot[middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddota ~
i 128 middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot4middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot-j-middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotfmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotfmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot
127e ~
126 ~~~=H~~-~=HmiddotrI~ ++~11 Room Ambient =2250 degC125
1 1 i Fresh Ambient =515 degC iii i i Freezer Ambient =-603 degC
124
1 10
Fig ES Mullion Temperature Profile Run 2 (Heater Off)
Run 2
2 3 4 5 6 7 8 9
TIC
84
146
145
a 144 ~
i 143
5 ~ 142
141
Run 3 9 0
---r-r--deg-r-ideg-t-9--rshyiii ltD T 11 ff = 15173 - OOI71x mu bull
middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotfmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotImiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot6middotmiddot
1Tmull~fz =14062 + J0158211x JLt 1
Q 1 1 1 middotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1-middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddoti-middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotimiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotoot-middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot-I-bullbullbull~bullbullbullbullbullbullbullbullbullbullbull
iii middotiiimiddot-j Room
1Am~t = 21~1 degC
iii i 1 Fresh Ambient = 563 degC 1 1 1 1 1 Freezer Ambient = -153 degC
14~---+--~----r---+---~---+--~----r---+-
1 2 3 4 5 6 7 8 9
TIC I
Fig E6 Mullion Temperature Profile Run 3 (Heater Off)
127
126
125 a ~
i 124
123 e ~
122
121
12
1
Fig E7
i i CD middotmiddotmiddotmiddot----middotmiddot-r--middot---middotmiddotmiddotmiddotmiddotmiddot-lmiddot--------middotmiddotmiddotmiddotl-middotmiddot---middotmiddotmiddotmiddot---r---middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1middotmiddotmiddotmiddotmiddot---middotmiddot---middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot-r----middot1__ _-
I I I T mulIff = 1321 - 001532x middotmiddotmiddotmiddot------middott--------------tmiddotmiddot----middot----middotmiddot-1------middotmiddotmiddotmiddotmiddotmiddot---jmiddot-----middotmiddotmiddotmiddotmiddotmiddotmiddotmiddot-lmiddotmiddotmiddot---middotmiddotmiddot-----tmiddotmiddotmiddotmiddotmiddot--middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddot-----middotmiddotmiddot6middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot
I cent I I I I -~~~~-ro-Tr-
r-middotmiddotmiddotmiddotrTTr-middotrmiddotrmiddotrmiddot middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddott middotmiddotmiddottmiddotmiddot1middotmiddotbullbullbullbull fmiddotbullbullbullbullbullbullbullmiddot-fbullbullbullbullbullbullbullmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot
II Room Ambil =21~3 degC iii i i Fresh Ambient =551 degc iii i i Freezer Ambient = -681 degC
2 3 4 5 6 7 8 9 10
TIC I
Mullion Temperature Profile Run 4 (Heater Off)
85
10
111
iii i i 11
Fttul5
T mu
=J=~[rr~tl=rI=109
a ~ 108 -t-t-t-i~FFl~i~~
+-0amp_- -+_bullbullbullbullbullbullbullbull+ - bullbullbull 107 11 f ~ 10325 + 0021893x 1 1 1 ji
5 bull Z iii
------~-~-----~---i --L--l ---_l__ ---L-----_shy106 ~
105 -t---i--+-+-+-middot++-I-shyL1LLL Room Ambient = 2177 C104 iii i i Fresh Ambient =448 degC
Freezer Ambient = -644 degC 103
1 2 3 4 5 6 7 8 9 10
TIC
Fig E8 Mullion Temperature Profile Run 5 (Heater Off)
86
34
33 1 1 1 1 1 1 1 1------I---------middotmiddot--+middotmiddotmiddotmiddot------middottmiddot-------middotmiddotmiddotmiddottmiddot----------middotmiddotmiddot---middot---middot----tmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot---middotmiddott--middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot(middotmiddotmiddotmiddotmiddot--
32 11 f =1 2859 ~ OI~X j
Till ff =133013 j - 007124x mu
31
a ~ 30
i 5 ~
29
28
27
26
Tmullfz = 26944 + 014842x
mu t-tr l
25 middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotjmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotjmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotlmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1middot ~ u~ ~it
24 lllti1 ~ i i ~ i
0 Lower Limit
23
0 1 2 3 4 5 6 7 8 9 10
ES Temperature Profile Plots From Mullion Data (Heater On)
The following are the remaining plots from the mullion heater analysis presented in Section
46
TIC I
Fig E9 Mullion Temperature Profile Run 2 (CenterHeater On)
Run 2
T muz
1
87
l----+
29
middotmiddotmiddotgtmiddotmiddoti middot 0 upper Limit 28 Run 1
I
middotmiddotI o
Tmullfz
T muo
LL~4cb 0 Lower Limit27
middot~+ImiddotmiddotmiddotImiddotmiddotmiddottr9middotdJmiddotmiddotmiddotmiddot 26
t T = 29465 008022xmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddot1middotmiddotmiddotmiddotTmiddotmiddotmiddotmiddot[middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1middot mullffa 25~
i 24 =24837+ 013186x middotlmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot+middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotimiddotmiddotmiddotmiddotmiddotmiddotmiddotlmiddotmiddotmiddotmiddotmiddotmiddot iii i i
i _ Jbullbullbullbullbullbullbullbullbullbullbullbullbulli l _l ii 23
e 22~ 21 +I~=tt=l=fit
L~LLL Tm~llff = 23856 005858x20 11 f = 1803 + 02243x z -rmiddotmiddotmiddotmiddot1middot middotmiddot middotmiddot 1middotmiddotmiddotmiddotmiddotTmiddotmiddot middot-rmiddot19
18
0 1 2 3 4 5 6 7 8 9 10
TIC
35
34
33
32
a ~ 31
I ~
30
29
28
27
26
25
24
Fig EI0
---bull---i----bullbullmiddotmiddotmiddotmiddot--~--------middotmiddot-+------ j bullbullbullbull ---bullbullbullbull -i--__---
T 11 f =30063 + OI~x 1 T i 134 196 i
0068 1 38
muz tmiddotmiddot Ilff=middot bull x ltP lt1gt mu
=t=H=t+t=R=t= F-6~I-i~E
Tmullfz = 28103 + 014486x 1middot++middot1middot1
middotmiddotmiddot--middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotimiddotmiddotmiddotmiddotmiddotmiddotmiddot-middotmiddotmiddotmiddotmiddot+middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotbullbullmiddotmiddotmiddot-middotmiddotimiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot~middotmiddot
111111 0 Upper Limit iii iii 0 Lower Limit
0 1 2 3 4 5 6 7 8 9 10
TIC
Mullion Temperature Profile Run 3 (CenterHeater On)
Fig Ell Mullion Temperature Profile Run 1 (LeftHeater On)
88
a
29
28
27
26
25~
i 24
23 e
22~ 21
20
19
18
Fig E12
i l middot middotmiddotmiddotmiddotlmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot+ 0 Upper Limit T 11 f =24474 + 011288x i imu bull z o Lower Limit
=tplusmntplusmnfrplusmnplusmnplusmn ~ I I I I Tmull ff ~ 28793 - o0784x
middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddott----middot------middotmiddotimiddot----middot-middotmiddot--middot-~-middotmiddotmiddot--middot----middotmiddot)middot
=ii=t=1=P-Ltplusmnt iii i T = 25599 - 00689xIfmiddotTTTmiddotmiddotrmiddot ~Ullff iii
T l1f =20552 + 01676x i~~imiddotimiddotmiddot
==~LL L LLLLL i i 1 ~ 1 ~
0 1 2 3 4 5 6 7 8 9 10
TIC I
Mullion Temperature Profile Run 2 (LeftlHeater On)
33 iii i i
-middot--middot(---middotmiddot--middotmiddot--middotmiddot+---middot-middotmiddotmiddotmiddot-middotmiddotmiddot~-middot--middot-------middoti---middot------~ o Upper Limit 32 Run 3
t bullbullbull +
Tm~llfz
T mu
1 1 1 1 1 o Lower Limit ~~31
=2713 ~ 0113~x j11Li30
a T ulff =30658 - 006506x 29~
IktlJ2~Li 28
27 e
26 =l=tt=tmiddotmiddottmiddott+~middot+=t=~ middotmiddot jmiddotjmiddottmiddottmiddotjmiddot T = 28288 - 00603x
iii i mullff 24
25
middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotQmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot+middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot~middotmiddotmiddot middotmiddotmiddotmiddotmiddotmiddotmiddotmiddot~middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot+middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot 11 fz = 2377 ~ 01788x IL11123 i i
22
0 1 2 3 4 5 6 7 8 9 10
TIC I
Fig E13 Mullion Temperature Profile Run 3 (LeftHeater On)
89
31
30
29
ltP ~u
J
1 T
-~Lti=t~-t--t i~+--Ij Tmu1lff =31473 middot005222x 28
1 1 1middot 1 l i l i bullbullbullbullbullbullbull__ bullbullbullbull_ bullbullbullbullbullbullbull~_bullbullbullbullbullbullbullbullbulla bullbullbullbullbullbullbullbullbullbullbull a 27
~ Tm~llfz = 26857 + 01734x _~__+_+II i
26
bullmiddotmiddotbullbullbullmiddotmiddotbullibullbullbullbullbullbullbullbullbullbullbullmiddotmiddotmiddotbullbullbullbullbullbullbullbullmiddotmiddotmiddotmiddot bullbullbullbullbullbullbullbullbull-i-~-i-ii25
JJ$~L-f$9 5 24
~ 23 middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotlmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot+middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot~middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot+middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1-middotmiddot T mllff =25622 bull 002~7X c-bullbullbullbullbullbullbullbullbullbullbullbull+ ~~ 22 rp 1 1 i i 1 1 1
21 = 19464 + 02548 jmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddott Upper Limitmullfz xii 0
4-bullbullbullbullbullbullbullbullbullbullbullbullimiddotmiddotmiddotbullbullbullbullbullbullmiddotf20 i 1 ~ 1
19
0 1 2 3 4 5 6 7 8 9 10
TIC I
Fig E14 Mullion Temperature Profile Run I (RightHeater On)
33 i
middotmiddotmiddotmiddotlaquomiddotmiddotmiddotmiddot------------------------------- c--------middotmiddotmiddot-middot-----------middotmiddotmiddot---middotmiddot--------l-----middot-----I-----32
= 2757 + 017006x ILLJ1
a
31
30
29~
i 28
Run2
TmulIfz
T~ulIfz ~
-~t=ii~Ii~~~~ i
27 middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot9-middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotT~~middotmiddotmiddotmiddotmiddot2s944-middot~middotmiddotO0278~middotmiddote 26~ r~rrTt+rr25
24 2320~ + O~S4x middotmiddotlmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotjmiddot ~ u~ L~t 23 middotmiddotmiddotmiddotmiddotmiddotmiddotmiddot~middotmiddotmiddotmiddotmiddotmiddotmiddot+middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot+middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot+middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotImiddotmiddotj 0 Lower Limit
22
0 1 2 3 4 5 6 7 8 9 10
TIC I
Fig EIS Mullion Temperature Profile Run 2 (RightlHeater On)
90
33 i i ~ _______ _ _~____ __ __-i--bullbullbullbullbullbullbullbull-t------ -- uu__~ ~ --~32
=1268931+ 0~4~14X 111131
30
a 29~
I 28
Run3
Tmullfz
i t+ I T
m
mnplusmn~~27 6 i 1 i 1 +++ T mullff =28912 - 002938x 26~ +middotmiddot++Imiddotjmiddott-25
= 22996 + 02312x 1middotmiddot+ 24
~~~~L lL1 0 ~23 ill 0 22
0 1 2 3 4 5 6 7 8 9 10
TIC
Fig E16 Mullion Temperature Profile Run 3 (RightHeater On)
91
APPENDIX F NUMERICAL SIMULATION EQUATIONS AND CODE
F1 Finite-Difference Equations
Figure Fl is a generic resistor network that is used as a base for all the finite-difference
equations The general fonn is
(Fl)
r----II ij+l
J
i j-l L ______--J
Fig F1 Generic Nodal Resistor Network
This makes it easy to simply plug in the different resistors for the different regions of the
section There are twelve resistors total The following table summarizes the resistors
needed to complete the model
Table F1 Model Resistors
Description Resistance [CIW]
Interior insulation x direction Rl= dx dymiddotkinsmiddotb
92
dyInterior insulation y direction R2= dx-kins-b
dySteel parallel with insulation y direction R3= km-dm-b + kins-(dx -dm)
dxR=Steel parallel with insulation x direction km-dm-b + kins-(dy -dm)
dyRs=Plastic parallel with insulation y direction
kp-dp-b + kins-(dx -dp)
dxPlastic parallel with insulation x direction R6= kp-dp-b + kins-(dy -dp)
heffa- (~- dm) + kinsSteel to exterior x direction R7= 2
heffo-kins-dy-b
heffa- (dY - dm) + kinsSteel to exterior y direction R - 28shyheffo-kins-dx-b
hefti- (dY _dm) + kinsSteel to interior y direction R9= 2
heffi-kins-dx-b
hefti- (~- dp) + kinsPlastic to interior x direction RIO= 2
heffi-kins-dy-b
Rll = hefti- (dJ -dP) + kinsPlastic to interior y direction
heffi-kins-dx-b
93
Steel skinplastic skin interface
2middotkmmiddotdmmiddotkpmiddotdpmiddotdxR12=----------------------~~----------------
2middotkmmiddotdmmiddotkpmiddotdpmiddotbmiddot(dy -dp) + (kpmiddotdp + kmmiddotdm)middotbmiddotdx2
F2 Wall Simulation Source Code
Program FiniteDiff
c This program simulates the conductive heat transfer through the wall section c of the refrigerator near the door gasket using Guass-Siedel iteration c The program allows for flexibility in the geometry and material properties c The program is a steady-state model
cVariable Definitions
c km = conductivity of the outer metal skin (Wm-K) c kins = conductivity of the polyurethane foam insulation (Wm-K) c kp conductivity of the inner plastic skin (Wm-K) c dm = thickness of the metal skin (mm) c dp = thickness of the plastic skin (mm) c b = depth of the section (m) c heffo = effective heat transfer coefficient on outside surfaces (Wm2-K) c heffi = effective heat transfer coefficient on inside surfaces (Wm2-K) c sl width of wall inSUlation (mm) c s2 length of wall section (mm) c s3 seal indentation (mm) c s4 seal width (mm) c s5 distance metal skin travels into cabinet (mm) c s6 distance platic skin travels out of cabinet (mm) c ns = number of nodes corresponding to the s regions above c rs = network resistors (m-eW) c i = integer values of distance along the x axis c j = integer values of distance along the y axis c imax maximum integer value in x direction c jmax maximum integer value in y direction c iter total number of iterations to converge c loop convergence flag c Qinl Heat flux per unit length across the outer boundary (Wm) c Qin2 Heat flux per unit length across the inner boundary (Wm) c Qdif Qinl - Qin2 (Wm) c Qpdif = percent difference between the heat fluxes Qinl and Qin2 c Ti Inside ambient temperature (e) c To = Outside ambient temperature (e)
cDeclare Variables
INTEGER nln2n3n4n5n6ijloopimaxjmaxiter INTEGER clflaglflag2 REAL kmkinskpdmdpdxdyheffoheffi REAL TiToQdifQpdifQinlQin2 REAL sls2s3s4s5s6lenoutlenin REAL rlr2r3r4r5r6r7r8r9rlOrllr12 REAL T(-1lOl-1lOl)bqlDsumlsum2 REAL Qm(lOl)qfluxm(lOl)fluxo(OlOl)fluxi(OlOl)
94
REAL fluxcen(0101)pfluxcen(0101)pfluxo(0101) REAL pfluxi(0101)pmaxdifoneDtolaq2Dqedge1
OPEN (10file-2Dcode(v11)out1position-rewind) OPEN (11file-2Dcode(v11)out2position=rewind)
cTest Parameters
c thermal conductivity of the outer metal skin (Wm K) km-540
c thermal conductivity of the wall insulation (Wm K) kins=0021
c thermal conductivity of the inner plastic skin (Wm K) kp=015
c thickness of the metal skin (mm) dm=065
c thickness of the plastic skin (mm) dp=25
c effective heat transfer coefficient on outside surfaces (Wm2-K) heffo=681
c effective heat transfer coefficient on inside surfaces (Wm2-K) heffi=610
c width of section (mm) sl=450
c length of section (mm) s2=2000
c depth of the section (m) b=10
c inside ambient temperature (C) Ti=95
c outside ambient temperature (C) To=210
c unit conversions dm=dm1000 dp=dp1000 sl=sl1000 s2=s21000
c specify 1-dimensional tolerance (t) oneDtol=30
cMesh Parameters
c specify the following nodal mesh parameters n1=20 n2=80 n3=1 n4=9 n5=10
c various mesh dimensions dx=sln1 dy=s2n2 s3=n3dx s4=n4dx s5=n5dx s6=sl-s5-dx n6=s6dx imax=n1-1 jmax=n2-1
cInitialize temperature matrix
DO 10 j=-1jmax+1 DO 20 i=-1imax+1 T(ij)=Ti
95
20 CONTINUE 10 CONTINUE
DO 30 j=Ojmax T(-Ij)=To
30 CONTINUE
DO 40 i=0n3 T(i-I)=To
40 CONTINUE
DO 50 j=Ojmax T(imax+lj)=Ti
50 CONTINUE
DO 60 i=n3+n4+1imax T(i-I)=Ti
60 CONTINUE
cResistors [m-CW]
c interior insulation x direction rl=dx(kinsdy)
c interior insulation y direction r2=dy(kinsdx)
c metalinsulation y direction r3=dy(kmdm+kins(dx-dm))
c metalinsulation x direction r4=dx(kmdm+kins(dy-dm))
c plasticinsulation y direction r5=dy(kpdp+kins(dx-dp))
c plasticinsulation x direction r6s dx(kpdp+kins(dy-dp))
c metal to exterior x direction r7=(heffolaquodx2)-dm)+kins)(heffokinsdy)
c metal to exterior y direction rB=(heffo laquody2)-dm) +kins)(heffokinsdx)
c metal to interior y direction r9=(heffilaquody2)-dm)+kins)(heffikinsdx)
c plastic to interior x direction rl0=(heffilaquodx2)-dp)+kins)(heffikinsdy)
c plastic to interior y direction rll=(heffilaquody2)-dp)+kins)(heffikinsdx)
c metalplastic interface rI2=(2kmdmkpdpdx)(2kmdmkpdp(dy-dp) + (kpdp+km dm)dxdx)
cxxxxxGuass-Siedel Iterationxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx loop=1 iter=1 DO WHILE (loop eq 1)
c Equations for row 0 i=O j=O CALL sseqn(Tr4r7r3rBijimaxjmax)
DO 70 i=ln3 j=O CALL sseqn(Tr4r4r2rBijimaxjmax)
70 CONTINUE
DO 75 i=n3+1n5-1
96
j=O IF (i le n3+n4) THEN
CALL sseqn(Tr4r4r21e20ijimaxjmax) ELSE
CALL sseqn(Tr4r4r2r9ijimaxjmax) ENDIF
75 CONTINUE
i=n5 j-O IF (i le n3+n4) THEN
CALL sseqn(Tr12r4r21e20ijimaxjmax) ELSE
CALL sseqn(Tr12r4r2r9ijimaxjmax) ENDIF
i=n5+1 j=O IF (i le n3+n4) THEN
CALL sseqn(Tr6r12r21e20ijimaxjmax) ELSE
CALL sseqn(Tr6r12r2rllijimaxjmax) ENDIF
DO 80 i=n5+2imax-l j=O IF (i le n3+n4) then
CALL sseqn(Tr6r6r21Oe20ijimaxjmax) ELSE
CALL sseqn(Tr6r6r2rllijimaxjmax) ENDIF
80 CONTINUE
i=imax j=O CALL sseqn(TrlOr6r5rllijimaxjmax)
c Equations for rows 1 thru jmax-l DO 90 j=ljmax-l
i=O CALL sseqn(Tr1r7r3r3ijimaxjmax)
DO 100 i=1imax-1 CALL sseqn(Tr1r1r2r2ijimaxjmax)
100 CONTINUE
i=imax CALL sseqn(Tr10r1r5r5ijimaxjmax)
90 CONTINUE
c Equations for row jmax j=jmax i=O CALL sseqn(Tr1r710e20r3ijimaxjmax)
DO 110 i=1imax-1 j=jmax CALL sseqn(Tr1r110e20r2ijimaxjmax)
110 CONTINUE
i=imax j=jmax CALL sseqn(Tr10r11Oe20r2ijimaxjmax)
97
c c c
Compute the difference in heat flux crossing the outer boundary and crossing the inner boundaryr ideally the difference should be zero
CALL balance(TToTidxdyn3n4imaxjmaxQdifQpdif c QinlQin2r7r9r8rlOrllb)
c Update loop variables iter-iter+l
c Convergence criterium IF (Qpdif le 20) then
loop-O ENDIF IF (iter eq 10000) THEN loop=O write(lO) Solution did not converge
ENDIF
END DO cxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
cHeat Transfer Calculations
c Compute 10 heat flux through wall CALL oneD (ToTiheffoheffikmkinskpdmdpslqlD)
c Compute the flux thru wall at each node on the c outside and inside walls [Wm2) Also the flux c in the x-direction across the center line of the c section
cl-int(nl2) fluxcen(0)=(1(r4dy))(T(cl0)-T(cl+l0)) fluxo(0)=(1(r7dy))(To-T(00)) fluxi(O)=(l(rlOdy))(T(imaxO)-Ti) DO 112 j=ljmax
fluxcen(j)=(l(rldy))(T(clj)-T(cl+lj)) fluxo(j)=(1(r7dy))(To-T(0j)) flumiddotxi (j) =(1 (rlOdy)) (T (imax j)-Ti)
112 CONTINUE
c Determine the percent of steady-state 10 losses DO 113 j=Ojmax
pfluxcen(j)=(fluxcen(j)qlD) 100 pfluxo(j)=(fluxo(j)qlD)lOO pfluxi(j)=(fluxi(j)qlD)lOO
113 CONTINUE
c Determine where the heat transfer becomes 10 c based on a criticle percentage
flagl=O DO 114 j=O jmax
a=abs(pfluxcen(j)-lOOO) IF (j ne jmax) THEN
IF (a le oneDtol) THEN jstar=j
ENDIF ELSE
IF (a le oneDtol) THEN jstar=j
ELSE flagl=l
ENDIF ENDIF
98
114 CONTINUE
c Determine the edge loss by subtracting the 10 heat c transfer from the heat transfer in the 20 region c across the centerline
flag2=0 IF (flagl eq 0) THEN
q2D=00 DO 115 j=O jstar
q2D-q2D+fluxcen(j) 115 CONTINUE
qedgel=q2D-qlD ELSE
flag2=1 ENDIF
c 10 heat flux along metal skin under the seal into c the cabinet [Wm2J Fluxes for all metal nodes are c computed as well as an average flux The flux from c node (n3+l0) to node (n3+20) is given as qlDm(l) c and so on Assume the temperature of the metal skin c is the temperature of the node at that location
suml=OO sum2=00 DO 119 i=n3+1n3+n4-l
Qm(i)=laquokmdmb)dx)(T(i0)-T(i+10raquo qfluxm(i)=(kmdx)(T(iO)-T(i+lOraquo suml=suml+Qm(i) sum2=sum2+qfluxm(i)
119 CONTINUE pmaxdif=laquoQm(n3+n4-l)-Qm(n3+1raquoQm(n3+lraquo100 qedge2-qfluxm(cl)
cOutput
c Output nodal temperatures to separate file DO 120 j=Ojmax
write(ll) (T(ij)i=Oimax) 120 CONTINUE
c Output flux info to a different file write(10) INPUT PARAMETERS write(lO) write (10 ) Section Dimensions (mm) write(lO) Width sl1000 write (10 ) Length s21000 write(10) Depth blOOO write(10) Steel skin thickness dmlOOO write(lO) Plastic skin thickness dplOOO write(lO) write(10) Mesh Geometry write(10) dx dxlOOO write(lO) dy dylOOO write(lO) Number nodes in x-direction n1 write(lO) Number nodes in y-direction n2 write(lO) Number of steel skin nodes write(lO) (including corner 00) n5+l write(10) Steel nodes under the seal n3+1 ton3+n4 write(10) write(lO) Steel skin conductivity (Wm K) km write(lO) Foam insulation conductivity (Wm K) kins write(lO) Plastic skin conductivity (Wm K) kp write(lO) Outside h (Wm2 K) heffo write(lO) Inside h (Wm2 K) heffi
99
write(10) Outside Temp (C) To write(10) Inside Temp (C) Ti write(10) write (10 ) write(10) write(10) OUPUT PARAMETERS write (10 ) write(10) Number of iterations iter write(10) write(10) Heat Transfer for the Section write(10) OVerall Heat Transfer (W) Qin1 write(10) 10 Heat Flux Thru Wall (Wm2) q1D write (10 ) write(10) Heat Transfer Along Metal Skin Under Seal write(10) node to node qm[Wm2J Qm[WJ DO 135 i=n3+1n3+n4-1
write(10) i i+1 qfluxm(i) Qm(i) 135 CONTINUE
write (10 ) Maximum difference () abs (pmaxdif) write(10) IF (flag2 eq 1) THEN
write(10) The mesh does not extend far enough write(10) in the y-direction to reach 10 heat write(10) transfer for the specified tolerance write(10) ofoneDtol
ELSE write (10 ) Edge loss computed from qe=q2D-q1D qedge1 write (10 ) write(10) Edge loss computed directly from write(10) steel skin ~T at centerline qedge2
ENDIF write (10 ) write (10 ) write(10) Heat fluxes in thru the section write(10) along the centerline [Wm2J write (10 ) write(10) j flux 10 DO 136 j=Ojmax
write(10) j fluxcen(j) pfluxcen(j) 136 CONTINUE
PAUSE STOP END
C
SUBROUTINE sseqn (Trplusirminusirplusjrminusj i jimax jmax)
c This subroutine computes the temperature at node (ij) c given the temperatures of the surrounding nodes and c the resistances leading to these nodes
INTEGER ijimaxjmax REAL T(-1101-1101)rplusirminusirplusjrminusj REAL c1c2c3c4c5
c1=1rplusi c2=1rminusi c3=1rplusj c4=1rminusj c5=c1+c2+c3+c4
T(ij)=(1c5)(c1T(i+1j)+c2T(i-1j)+c3T(ij+1)+c4T(ij-1raquo
100
RETURN END
C
SUBROUTINE balance(TToTidxdyn3n4imaxjmaxQdifQpdif c Qin1Qin2r7r8r9r10r11b)
c This subroutine computes the steady-state heat balance c for the cross-section
INTEGER imaxjmaxijn3n4 REAL T(-1101-1101)TlToQin1Qin2dydx REAL r7r8r9r10r11b
c Compute the heat entering Qin1 [Wj Qin1=00 DO 10 jOjmax
Qin1=Qin1+(b(r7))(To-T(0j)) 10 CONTINUE
DO 20 i=0n3 Qin1=Qin1+(b(r8))(To-T(i0))
20 CONTINUE
c Compute the heat leaving Qin2 [Wj Qin2=00 DO 30 j=Ojmax
Qin2=Qin2+(b(r10))(T(imaxj)-Ti) 30 CONTINUE
DO 40 i=n3+n4+1imax IF (i le nS) then
Qin2=Qin2+(b(r9))(T(i0)-Ti) ELSE
Qin2=Qin2+(b(r11))(T(i0)-Ti) ENDIF
40 CONTINUE
c Compute the absolute difference in heat fluxes [Wj Qdif=abs(Qin2-Qin1)
c Compute the percent difference in the heat transfers [Wj Qpdif=(QdifQin1) 100
RETURN END
C
SUBROUTINE oneD (ToTiheffoheffikmkinskpdmdpslqlD)
c This subroutine compute the one-dimensional c heat flux through the section wall
INTEGER i REAL ToTiheffoheffikmkinskpdmdpsl REAL q1DReqdins
dins=sl-dm~dp
Req=(lheffo) + (dmkm) + (dinskins) +(dpkp)+(lheffi) q1D=(To-Ti)Req
RETURN END
101
F3 Fresh Food Wan Simulation Output
INPUT PARAMETERS
Section Dimensions (mm) Width 4500 Length 2000 Depth 1000 Steel skin thickness 6500 Plastic skin thickness 2500
Mesh Geometry dx 2250 dy 2500 Number nodes in x-direction 20 Number nodes in y-direction 80 Number of steel skin nodes (including corner 00) 11 Steel nodes under the seal 2 to 10
Steel skin conductivity (Wm K) 5400 Foam insulation conductivity (Wm K) 21000E-02 Plastic skin conductivity (Wm K) 1500 Outside h (Wm2 K) 6810 Inside h (Wm2 K) 6100 Outside Temp (C) 2100 Inside Temp (C) 4000
OUPUT PARAMETERS
Number of iterations 5318
10 Heat Flux Thru Wall (Wm2) 9132
Heat Transfer Along Metal Skin Under Seal node to node qm[Wm2] Qm[W]
2 3 1619 1092 3 4 1612 1081 4 5 1660 1019 5 6 1645 1010 6 1 1626 1051 1 8 1601 1041 8 9 1569 1020 9 10 1521 9922
Maximum difference () 9101
Edge loss computed directly from steel skin 1T at centerline 1645
Heat fluxes in thru the section along the centerline [Wm2]
j flux 10 0 4284 4691 1 2246 2459 2 3513 3841 3 4554 4981 4 5311 5881 5 6001 6512 6 6488 1104 1 6868 1520
102
10
20
30
40
50
60
70
8 7169 7850 9 7412 8117
7612 8335 11 7778 8517 12 7918 8670 13 8037 8800 14 8139 8912 15 8227 9008 16 8303 9092 17 8369 9164 18 8428 9228 19 8479 9285
8525 9334 21 8565 9379 22 8601 9418 23 8634 9454 24 8663 9486 25 8690 9515 26 8714 9542 27 8736 9566 28 8756 9588 29 8775 9609
8793 9628 31 8809 9645 32 8824 9662 33 8838 9677 34 8851 9692 35 8863 9705 36 8875 9718 37 8886 9730 38 8896 9742 39 8906 9752
8916 9763 41 8925 9772 42 8933 9782 43 8941 9791 44 8949 9799 45 8956 9807 46 8963 9815 47 8970 9822 48 8976 9829 49 8982 9836
8988 9842 51 8994 9848 52 8999 9854 53 9004 9859 54 9009 9864 55 9013 9869 56 9017 9874 57 9021 9878 58 9025 9883 59 9029 9887
9032 9890 61 9036 9894 62 9039 9897 63 9042 9901 64 9044 9903 65 9047 9906 66 9049 9909 67 9051 9911 68 9053 9913 69 9055 9915
9057 9917 71 9058 9919
103
72 9059 9920 73 9061 9921 74 9062 9922 75 9062 9923 76 9063 9924 77 9063 9924 78 9064 9925 79 9064 9925
j local Qwall [Wl
-1 3215 0 -45410E-02 1 -50708E-02 2 -40940E-02 3 -33836E-02 4 -27620E-02 5 -23180E-02 6 -1 9628E-02 7 -1 6076E-02 8 -1 4300E-02 9 -12524E-02 10 -10748E-02 11 -98601E-03 12 -89722E-03 13 -80842E-03 14 -71962E-03 15 -63081E-03 16 -63082E-03 17 -54202E-03 18 -54202E-03 19 -45322E-03 20 -45322E-03 21 -45322E-03 22 -45321E-03 23 -36442E-03 24 -36442E-03 25 -36442E-03 26 -27562E-03 27 -27561E-03 28 -27561E-03 29 -27561E-03 30 -27561E-03 31 -18682E-03 32 -18682E-03 33 -27561E-03 34 -18682E-03 35 -18682E-03 36 -18681E-03 37 -18682E-03 38 -98018E-04 39 -98018E-04 40 -98018E-04 41 -98018E-04 42 -98018E-04 43 -98018E-04 44 -98018E-04 45 -98018E-04 46 -98018E-04 47 -18682E-03 48 -98018E-04 49 -98018E-04 50 -98018E-04 51 -98018E-04 52 -98018E-04
104
53 -98018E-04 54 -92160E-05 55 -98018E-04 56 -98018E-04 57 -98018E-04 58 -98018E-04 59 -98018E-04 60 -92160E-05 61 -98018E-04 62 -92160E-05 63 -98018E-04 64 -98018E-04 65 -92160E-05 66 -98018E-04 67 -98018E-04 68 -92245E-05 69 -92245E-05 70 -98018E-04 71 -98018E-04 72 -98018E-04 73 -92160E-05 74 -92160E-05 75 -92160E-05 76 -92160E-05 77 -92160E-05 78 -92160E-05 79 -92160E-05
Qwallff [Wm21 = 1442 Qwallff [WI = 2775
Fresh Food Nodal Temperatures
x(mm) v(mm) 1125 3375 5625 7875 10125 12375 14625 16875 19125 21375
125 1761 1755 1748 1741 1734 1727 172 1713 1706 17 375 1768 1753 1738 1723 1707 169 1671 165 1624 1589 625 1775 1752 173 1706 1682 1656 1626 1593 1552 15 875 1781 1751 1722 1691 1659 1625 1587 1544 1494 1434
1125 -1787 1751 1715 1678 1639 1598 1553 1504 1448 1384 1375 1792 1751 1709 1667 1622 1576 1526 1471 1412 1346 1625 1798 1752 1705 1658 1609 1557 1503 1446 1384 ll17 1875 1803 1753 1702 165 1597 1543 1485 1425 1362 1294 2125 1808 1754 17 1645 1589 1531 1471 1409 1344 1276 2375 1813 1756 1699 1641 1582 1522 146 1396 133 1262 2625 1817 1758 1698 1638 1577 1515 1451 1386 132 1251 2875 1822 176 1698 1636 1573 151 1445 1379 1311 1242 3125 1826 1762 1699 1635 1571 1506 144 1373 1304 1235 3375 183 1765 17 1635 1569 1503 1436 1368 1299 1229 3625 1834 1768 1701 1635 1568 1501 1433 1364 1295 1225 3875 1837 177 1703 1635 1568 15 1431 1362 1292 1222 4125 1841 1773 1705 1636 1568 1499 143 136 129 1219 4375 1845 1776 1707 1638 1568 1499 1429 1359 1289 1218 4625 1848 1778 1709 1639 1569 1499 1429 1358 1288 1216 4875 1851 1781 1711 164 157 15 1429 1358 1287 1216 5125 1854 1784 1713 1642 1571 15 1429 1358 1287 1215 5375 1857 1786 1715 1644 1573 1501 143 1358 1287 1215 5625 186 1789 1717 1646 1574 1502 1431 1359 1287 1215
105
5875 1863 1791 1719 1647 1576 1504 1432 136 1288 1215 6125 1866 1794 1721 1649 1577 1505 1433 136 1288 1216 6375 1868 1796 1723 1651 1579 1506 1434 1361 1289 1216 6625 1871 1798 1725 1653 158 1508 1435 1362 129 1217 6875 1873 18 1727 1655 1582 1509 1436 1363 1291 1218 7125 1876 1803 1729 1656 1583 151 1437 1364 1291 1218 7375 1878 1805 1731 1658 1585 1512 1439 1366 1292 1219 7625 188 1807 1733 166 1587 1513 144 1367 1293 122 7875 1882 1809 1735 1661 1588 1515 1441 1368 1294 1221 8125 1884 181 1737 1663 159 1516 1442 1369 1295 1222 8375 1886 1812 1738 1665 1591 1517 1444 137 1296 1223 8625 1888 1814 174 1666 1592 1519 1445 1371 1297 1224 8875 189 1816 1742 1668 1594 152 1446 1372 1298 1225 9125 1892 1817 1743 1669 1595 1521 1447 1373 1299 1225 9375 1893 1819 1745 1671 1596 1522 1448 1374 13 1226 9625 1895 182 1746 1672 1598 1524 1449 1375 1301 1227 9875 1896 1822 1748 1673 1599 1525 145 1376 1302 1228 10125 1898 1823 1749 1674 16 1526 1451 1377 1303 1229 10375 1899 1825 175 1676 1601 1527 1452 1378 1304 123 10625 1901 1826 1751 1677 1602 1528 1453 1379 1305 123 10875 1902 1827 1753 1678 1603 1529 1454 138 1305 1231 11125 1903 1828 1754 1679 1604 153 1455 1381 1306 1232 11375 1904 183 1755 168 1605 1531 1456 1381 1307 1232 11625 1906 1831 1756 1681 1606 1532 1457 1382 1308 1233 11875 1907 1832 1757 1682 1607 1532 1458 1383 1308 1234 12125 1908 1833 1758 1683 1608 1533 1458 1384 1309 1234 12375 1909 1834 1759 1684 1609 1534 1459 1384 131 1235 12625 191 1835 176 1685 161 1535 146 1385 131 1235 12875 1911 1836 1761 1686 1611 1536 1461 1386 1311 1236 13125 1912 1837 1761 1686 1611 1536 1461 1386 1311 1236 13375 1913 1837 1762 1687 1612 1537 1462 1387 1312 1237 13625 1913 1838 1763 1688 1613 1538 1462 1387 1312 1237 13875 1914 1839 1764 1688 1613 1538 1463 1388 1313 1238 14125 1915 184 1764 1689 1614 1539 1464 1388 1313 1238 14375 1916 184 1765 169 1614 1539 1464 1389 1314 1239 14625 1916 1841 1766 169 1615 154 1465 1389 1314 1239 14875 1917 1842 1766 1691 1616 154 1465 139 1315 1239 15125 1918 1842 1767 1691 1616 1541 1465 139 1315 124 15375 1918 1843 1767 1692 1616 1541 1466 1391 1315 124 15625 1919 1843 1768 1692 1617 1542 1466 1391 1316 124 15875 1919 1844 1768 1693 1617 1542 1467 1391 1316 1241 16125 192 1844 1769 1693 1618 1542 1467 1392 1316 1241 16375 192 1844 1769 1694 1618 1543 1467 1392 1317 1241 16625 192 1845 1769 1694 1618 1543 1468 1392 1317 1241 16875 1921 1845 177 1694 1619 1543 1468 1392 1317 1242 17125 1921 1846 177 1694 1619 1544 1468 1393 1317 1242 17375 1921 1846 177 1695 1619 1544 1468 1393 1317 1242 17625 1922 1846 1771 1695 1619 1544 1469 1393 1318 1242 17875 1922 1846 1771 1695 162 1544 1469 1393 1318 1242 18125 1922 1847 1771 1695 162 1544 1469 1393 1318 1243 18375 1922 1847 1771 1696 162 1545 1469 1394 1318 1243 18625 1923 1847 1771 1696 162 1545 1469 1394 1318 1243 18875 1923 1847 1771 1696 162 1545 1469 1394 1318 1243 19125 1923 1847 1772 1696 162 1545 1469 1394 1318 1243 19375 1923 1847 1772 1696 162 1545 1469 1394 1318 1243 19625 1923 1847 1772 1696 1621 1545 1469 1394 1318 1243 19875 1923 1847 1772 1696 1621 1545 1469 1394 1318 1243
106
x(mm) y(mm) 23625 25875 28125 30375 32625 34875 37125 39375 41625 43875
125 1694 1662 1287 1033 8577 7336 6444 5795 5324 4995 375 1536 144 125 1068 9163 7946 6974 6189 5532 4944 625 1431 1334 1203 1066 9379 8252 7275 6423 5657 4935 875 136 127 1164 1051 9408 8374 7423 6548 573 4941
1125 131 1226 1132 1034 9353 8394 7477 6605 5766 4948 1375 1273 1193 1107 1017 9262 836 7478 6618 5779 4952 1625 1245 1168 1086 1002 9162 8302 7449 6607 5776 4951 1875 1223 1148 1069 9886 9064 8236 7408 6583 5764 4948 2125 1205 1132 1055 977 8974 8169 7362 6554 5747 4941 2375 1191 1119 1044 9671 8893 8107 7316 6522 5728 4933 2625 118 1108 1034 9588 8824 8051 7273 6492 5709 4925 2875 1172 11 1026 9518 8764 8002 7235 6464 5691 4916 3125 1164 1093 102 946 8713 796 7201 6439 5674 4908 3375 1159 1087 1015 9412 8671 7924 7172 6417 566 49 3625 1154 1083 101 9373 8636 7894 7148 6399 5647 4894 3875 1151 1079 1007 9341 8608 7869 7128 6383 5636 4888 4125 1148 1077 1004 9316 8585 7849 7111 637 5627 4883 4375 1146 1074 1002 9296 8566 7833 7097 6359 5619 4879 4625 1145 1073 1001 9281 8552 7821 7087 6351 5613 4875 4875 1144 1072 9995 927 8541 7811 7078 6344 5609 4872 5125 1143 1071 9987 9261 8533 7803 7072 6339 5605 487 5375 1143 1071 9982 9256 8528 7798 7067 6335 5602 4868 5625 1143 107 9979 9253 8524 7795 7064 6332 56 4867 5875 1143 107 9978 9251 8522 7793 7062 6331 5599 4866 6125 1143 1071 9979 9251 8522 7792 7061 633 5598 4866 6375 1144 1071 9981 9252 8523 7792 7061 633 5598 4865 6625 1144 1071 9984 9255 8524 7793 7062 633 5598 4865 6875 1145 1072 9988 9258 8526 7795 7063 6331 5598 4865 7125 1145 1072 9993 9261 8529 7797 7065 6332 5599 4866 7375 1146 1073 9998 9265 8533 78 7067 6333 56 4866 7625 1147 1074 10 927 8536 7803 7069 6335 5601 4867 7875 1148 1074 1001 9275 854 7806 7072 6337 5602 4867 8125 1148 1075 1001 928 8545 7809 7074 6339 5603 4868 8375 1149 1076 1002 9285 8549 7813 7077 6341 5605 4869 8625 115 1076 1003 929 8553 7817 708 6343 5606 4869 8875 1151 1077 1003 9295 8558 782 7083 6345 5608 487 9125 1152 1078 1004 93 8562 7824 7086 6347 5609 4871 9375 1152 1078 1004 9306 8567 7828 7089 635 5611 4872 9625 1153 1079 1005 9311 8571 7831 7092 6352 5612 4873 9875 1154 108 1006 9316 8575 7835 7094 6354 5614 4873 10125 1155 108 1006 9321 858 7838 7097 6356 5615 4874 10375 1155 1081 1007 9326 8584 7842 71 6358 5617 4875 10625 1156 1082 1007 933 8588 7845 7103 636 5618 4876 10875 1157 1082 1008 9335 8592 7848 7105 6362 5619 4876 11125 1157 1083 1008 9339 8596 7852 7108 6364 5621 4877 11375 1158 1083 1009 9344 8599 7855 711 6366 5622 4878 11625 1158 1084 1009 9348 8603 7858 7113 6368 5623 4879 11875 1159 1084 101 9352 8606 7861 7115 637 5625 4middot879 12125 116 1085 101 9356 861 7864 7117 6372 5626 488 12375 116 1085 1011 936 8613 7866 712 6373 5627 488 12625 1161 1086 1011 9363 8616 7869 7122 6375 5628 4881 12875 1161 1086 1011 9367 8619 7871 7124 6376 5629 4882 13125 1162 1087 1012 937 8622 7874 7126 6378 563 4882 13375 1162 1087 1012 9373 8625 7876 7128 6379 5631 4883 13625 1162 1087 1013 9376 8627 7878 7129 6381 5632 4883
107
13875 1163 1088 1013 9379 863 788 7131 6382 5633 4884 14125 1163 1088 1013 9382 8632 7882 7133 6383 5634 4884 14375 1164 1089 1013 9384 8634 7884 7134 6384 5634 4885 14625 1164 1089 1014 9387 8636 7886 7136 6385 5635 4885 14875 1164 1089 1014 9389 8638 7888 7137 6386 5636 4885 15125 1165 1089 1014 9392 864 7889 7138 6387 5637 4886 15375 1165 109 1015 9394 8642 7891 714 6388 5637 4886 15625 1165 109 1015 9396 8644 7892 7141 6389 5638 4886 15875 1165 109 1015 9398 8646 7894 7142 639 5638 4887 16125 1166 109 1015 9399 8647 7895 7143 6391 5639 4887 16375 1166 1091 1015 9401 8649 7896 7144 6392 5639 4887 16625 1166 1091 1016 9403 865 7897 7145 6392 564 4888 16875 1166 1091 1016 9404 8651 7898 7146 6393 564 4888 17125 1167 1091 1016 9405 8652 7899 7146 6394 5641 4888 17375 1167 1091 1016 9406 8653 79 7147 6394 5641 4888 17625 1167 1091 1016 9407 8654 7901 7148 6395 5641 4888 17875 1167 1092 1016 9408 8655 7902 7148 6395 5642 4889 18125 1167 1092 1016 9409 8656 7902 7149 6395 5642 4889 18375 1167 1092 1016 941 8656 7903 7149 6396 5642 4889 18625 1167 1092 1016 9411 8657 7903 715 6396 5642 4889 18875 1167 1092 1017 9411 8657 7904 715 6396 5643 4889 19125 1167 1092 1017 9412 8658 7904 715 6396 5643 4889 19375 1167 1092 1017 9412 8658 7904 715 6397 5643 4889 19625 1167 1092 1017 9412 8658 7904 715 6397 5643 4889 19875 1168 1092 1017 9412 8658 7904 715 6397 5643 4889
F4 Freezer Wall Simulation Output
INPUT PARAMETERS
Section Dimensions (mm) Width 5600 Length 2000 Depth 1000 Steel skin thickness 6500 Plastic skin thickness 2500
Mesh Geometry dx 2800 dy 2500 Number nodes in x-direction 20 Number nodes in y-direction 80 Number of steel skin nodes (including corner 00) 9 Steel nodes under the seal 2 to 8
Steel skin conductivity (Wm K) 5400 Foam insulation conductivity (Wm K) 27000E-02 Plastic skin conductivity (Wm K) 1500 Outside h (Wm2 K) 6870 Inside h (Wm2 K) 6410 Outside Temp (C) 2100 Inside Temp (C) -1000
OUPUT PARAMETERS
108
Number of iterations 5409
Heat Transfer for the Section OVerall Heat Transfer (WI 4518 10 Heat Flux Thru Wall (Wm21 1362
Heat Transfer Along Metal Skin Under Seal node to node
2 3 3 4 4 5 5 6 6 7 7 8
Maximum difference
qm[Wm2) Om(W) 3026 1967 3008 1955 2981 1938 2944 1914 2892 1880 2820 1833
(1 6799
Edge loss computed from qe=q20-q1D 1760
Edge loss compusteel skin AT
ted directly from at centerline 2981
Heat fluxes in thru the section along the centerline [Wm2)
j flux UO 0 7762 5698 1 3711 2724 2 5678 41 68 3 7275 5341 4 8508 6246 5 9437 6927 6 1013 7438 7 1066 7823 8 1106 8117 9 1137 8347 10 1162 8529 11 1182 8678 12 1199 8801 13 1213 8904 14 1225 8992 15 1235 9068 16 1244 9135 17 1252 9193 18 1259 9245 19 1266 9291 20 1271 9333 21 1276 9370 22 1281 9405 23 1285 9436 24 1289 9464 25 1293 9491 26 1296 9515 27 1299 9538 28 1302 9559 29 1305 9578 30 1307 9596 31 1310 9614 32 1312 9630 33 1314 9645 34 1316 9659 35 1318 9673 36 1319 9685 37 1321 9697
109
38 1323 9709 39 1324 9720 40 1325 9730 41 1327 9740 42 1328 9749 43 1329 9758 44 1330 9767 45 1332 9775 46 1333 9783 47 1334 97bull 90 48 1335 9797 49 1336 9804 50 1336 9810 51 1337 9816 52 1338 9822 53 1339 9828 54 1340 9833 55 1340 9838 56 1341 9843 57 1341 9847 58 1342 9852 59 1343 9856 60 1343 9859 61 1344 9863 62 1344 9866 63 1344 9870 64 1345 9873 65 1345 9875 66 1346 9878 67 1346 9880 68 1346 9882 69 1347 9884 70 1347 9886 71 1347 9888
72 1347 9889 73 1347 9891 74 1347 9892 75 1348 9893 76 1348 9893 77 1348 9894 78 1348 9894 79 1348 9894
j local Qwall [WI
-1 3067 0 -36774E-02 1 -40214E-02 2 -32314E-02 3 -25994E-02 4 -20859E-02 5 -16909E-02 6 -14144E-02 7 -12169E-02 8 -10589E-02 9 -90092E-03 10 -78242E-03 11 -70342E-03 12 -66392E-03 13 -58492E-03 14 -54542E-03 15 -50592E-03 16 -46642E-03 17 -42692E-03 18 -42692E-03
110
19 -38742E-03 20 -34792E-03 21 -30842E-03 22 -30842E-03 23 -30842E-03 24 -26892E-03 25 -26892E-03 26 -22942E-03 27 -22942E-03 28 -22942E-03 29 -22942E-03 30 -18992E-03 31 -1 8992E-03 32 -18992E-03 33 -18992E-03 34 -1 8992E-03 35 -1 5042E-03 36 -1 8992E-03 37 -15042E-03 38 -1 5042E-03 39 -11092E-03 40 -11092E-03 41 -11092E-03 42 -11092E-03 43 -11092E-03 44 -11092E-03 45 -11092E-03 46 -11092E-03 47 -71417E-04 48 -11092E-03 49 -71421E-04 50 -11092E-03 51 -71417E-04 52 -11092E-03 53 -71417E-04 54 -71421E-04 55 -71421E-04 56 -71417E-04 57 -31916E-04 58 -31920E-04 59 -31916E-04 60 -31916E-04 61 -71417E-04 62 -11421E-04 63 -71421E-04 64 -31920E-04 65 -31920E-04 66 -71417E-04 67 -31916E-04 68 -71417E-04 69 -31920E-04 70 -71421E-04 71 -31920E-04 72 -31920E-04 73 -71417E-04 74 -31916E-04 75 -31916E-04 76 -31916E-04 77 -31916E-04 78 -71417E-04 79 -71417E-04
Qwallfz [Wm2J = 2895 Qwallfz [WJ = 2721
111
Freezer Wan Nodal Temperatures
x(mm) y1mm 14 42 70 98 126 154 182 210 238 266
125 1507 1492 1477 1461 1445 143 1415 14 1385 1338 375 1519 1489 1458 1426 1392 1353 1307 1247 1154 972 625 1531 1486 1441 1393 1341 1282 1212 1121 9925 7989 875 1542 1484 1425 1363 1296 1221 1132 1023 8837 7014
1125 1553 1483 1412 1338 1258 117 1069 9508 809 6396 1375 1563 1483 1401 1317 1227 1129 102 8969 7563 5974 1625 1572 1483 1393 13 1202 1097 9824 8568 7184 5673 1875 1582 1485 1387 1287 1182 1072 9537 8269 6906 5452 2125 1591 1488 1384 1277 1167 1053 9321 8046 67 5288 2375 1599 1491 1382 1271 1157 1039 916 7881 6547 5164 2625 1608 1495 1381 1266 1149 1028 9041 7758 6433 5071 2875 1616 1499 1382 1264 1144 1021 8955 7668 6349 5002 3125 1623 1504 1384 1263 114 1016 8895 7604 6288 495 3375 1631 1509 1386 1263 1139 1013 8854 7559 6245 4913 3625 1638 1514 1389 1264 1138 1011 8829 753 6216 4888 3875 1645 1519 1393 1266 1139 1011 8816 7513 6198 4872 4125 1652 1524 1396 1269 114 1011 8813 7505 6188 4863 4375 1658 1529 14 1271 1142 1012 8817 7505 6185 486 4625 1664 1534 1405 1275 1144 1014 8826 751 6188 4861 4875 167 1539 1409 1278 1147 1016 884 752 6195 4867 5125 1676 1544 1413 1281 115 1018 8858 7533 6206 4875 5375 1682 1549 1417 1285 1153 102 8877 755 6219 4886 5625 1687 1554 1421 1289 1156 1023 8899 7568 6235 4899 5875 1692 1559 1425 1292 1159 1026 8923 7588 6252 4914 6125 1698 1563 143 1296 1162 1028 8947 7609 627 493 6375 1702 1568 1434 1299 1165 1031 8972 763 6289 4946 6625 1707 1572 1438 1303 1169 1034 8997 7653 6308 4964 6875 1712 1576 1441 1306 1172 1037 9022 7675 6329 4982 7125 1716 158 1445 131 1175 104 9048 7698 6349 5 7375 172 1584 1449 1313 1178 1043 9073 7721 6369 5018 7625 1724 1588 1452 1317 1181 1045 9098 7744 639 5036 7875 1728 1592 1456 132 1184 1048 9123 7766 641 5054 8125 1732 1595 1459 1323 1187 1051 9147 7788 643 5072 8375 1736 1599 1462 1326 1189 1053 917 781 645 509 8625 1739 1602 1465 1329 1192 1056 9194 7831 6469 5108 8875 1743 1605 1468 1332 1195 1058 9216 7852 6488 5125 9125 1746 1609 1471 1334 1197 1061 9238 7872 6507 5142 9375 1749 1612 1474 1337 12 1063 926 7892 6525 5158 9625 1752 1615 1477 134 1202 1065 9281 7911 6542 5174 9875 1755 1617 148 1342 1205 1067 9301 793 656 519 10125 1758 162 1482 1344 1207 1069 9321 7948 6576 5205 10375 1761 1623 1485 1347 1209 1071 934 7966 6593 522 10625 1763 1625 1487 1349 1211 1073 9358 7983 6608 5234 10875 1766 1627 1489 1351 1213 1075 9376 7999 6623 5248 11125 1768 163 1491 1353 1215 1077 9393 8015 6638 5262 11375 1771 1632 1494 1355 1217 1079 941 8031 6652 5275 11625 1773 1634 1496 1357 1219 1081 9426 8045 6666 5287 11875 1775 1636 1498 1359 1221 1082 9441 806 6679 53 12125 1777 1638 1499 1361 1222 1084 9456 8073 6692 5311 12375 1779 164 1501 1362 1224 1085 947 8087 6704 5322 12625 1781 1642 1503 1364 1225 1087 9483 8099 6716 5333 12875 1783 1644 1505 1366 1227 1088 9496 8111 6727 5344
112
13125 1784 1645 1506 1367 1228 109 9509 8123 6738 5353 13375 1786 1647 1508 1369 123 1091 9521 8134 6748 5363 13625 1788 1648 1509 137 1231 1092 9532 8145 6758 5372 13875 1789 165 151 1371 1232 1093 9543 8155 6768 5381 14125 1791 1651 1512 1373 1233 1094 9554 8165 6777 5389 14375 1792 1652 1513 1374 1235 1095 9564 8174 6785 5397 14625 1793 1654 1514 1375 1236 1096 9573 8183 6793 5404 14875 1794 1655 1515 1376 1237 1097 9582 8191 6801 5412 15125 1796 1656 1516 1377 1238 1098 959 8199 6808 5418 15375 1797 1657 1517 1378 1238 1099 9598 8206 6815 5425 15625 1798 1658 1518 1379 1239 11 9606 8213 6822 5431 15875 1799 1659 1519 138 124 1101 9613 822 6828 5436 16125 18 166 152 138 1241 1101 9619 8226 6834 5442 16375 18 1661 1521 1381 1242 1102 9626 8232 6839 5446 16625 1801 1661 1521 1382 1242 1103 9631 8237 6844 5451 16875 1802 1662 1522 1382 1243 1103 9637 8242 6848 5455 17125 1803 1663 1523 1383 1243 1104 9642 8247 6853 5459 17375 1803 1663 1523 1384 1244 1104 9646 8251 6857 5463 17625 1804 1664 1524 1384 1244 1105 965 8255 686 5466 17875 1804 1664 1524 1384 1245 1105 9654 8258 6863 5469 18125 1805 1665 1525 1385 1245 1105 9657 8261 6866 5471 18375 1805 1665 1525 1385 1245 1106 966 8264 6869 5474 18625 1805 1665 1525 1385 1246 1106 9662 8266 6871 5476 18875 1806 1666 1526 1386 1246 1106 9664 8268 6872 5477 19125 1806 1666 1526 1386 1246 1106 9666 827 6874 5479 19375 1806 1666 1526 1386 1246 1106 9667 8271 6875 548 19625 1806 1666 1526 1386 1246 1107 9668 8271 6876 548 19875 1806 1666 1526 1386 1246 1107 9668 8272 6876 5481
x(mm) v(mm) 294 322 350 378 406 434 462 490 518 546
125 549 054 -27 -5 -624 -727 -8 -85 -89 -92 375 548 171 -12 -338 -5 -624 -719 -795 -858 -914 625 51 22 -032 -24 -408 -543 -654 -748 -83 -907 875 474 238 0182 -175 -34 -482 -603 -71 -807 -898
1125 445 243 048 -132 -293 -436 -564 -68 -787 -89 1375 423 243 0653 -103 -259 -402 -534 -656 -772 -883 1625 406 24 0752 -084 -236 -378 -511 -638 -759 -877 1875 393 237 0808 -071 -219 -36 -495 -624 -749 -871 2125 382 233 0837 -063 -208 -348 -483 -614 -741 -867 2375 374 23 085 -058 -2 -339 -474 -606 -735 -863 2625 368 227 0855 -055 -195 -332 -467 -6 -731 -86 2875 363 225 0855 -053 -191 -328 -462 -596 -728 -858 3125 36 223 0853 -052 -189 -324 -459 -593 -725 -856 3375 357 221 0851 -051 -187 -322 -457 -59 -723 -855 3625 355 22 0849 -05 -186 -32 -455 -588 -722 -854 3875 354 219 0849 -049 -185 -319 -453 -587 -72 -853 4125 353 219 0849 -049 -184 -318 -452 -586 -72 -853 4375 353 219 0852 -049 -183 -317 -451 -585 -719 -852 4625 353 219 0855 -048 -183 -317 -451 -584 -718 middot852 4875 353 22 0861 -047 -182 -316 -45 -584 -718 -852 5125 354 22 0867 -047 -181 -315 -449 -584 -717 -851 5375 355 221 0875 -046 -181 -315 -449 -583 -717 -851 5625 356 222 0884 -045 -18 -314 -448 -582 -717 -851 5875 358 223 0894 -044 -179 -313 -448 -582 -716 -851 6125 359 225 0904 -043 -178 -313 -447 -582 -716 -851 6375 36 226 0915 -043 -177 -312 -447 -581 -716 -85
113
6625 362 227 0927 -042 -177 -311 -446 -581 -716 -85 6875 363 229 0939 -04 -176 -311 -445 -58 -715 -85 7125 365 23 0951 -039 -175 -31 -445 -58 -715 -85 7375 367 232 0964 -038 -174 -309 -444 -579 -715 -85 7625 368 233 0976 -037 -173 -308 -444 -579 -714 -85 7875 37 234 0989 -036 -172 -308 -443 -578 -714 -849 8125 371 236 1 -035 -171 -307 -442 -578 -714 -849 8375 373 237 101 -034 -17 -306 -442 -578 -713 -849 8625 375 239 103 -033 -169 -305 -441 -577 -713 -849 8875 376 24 104 -032 -168 -305 -441 -577 -713 -849 9125 378 241 105 -031 -168 -304 -44 -576 -712 -849 9375 379 243 106 -03 -167 -303 -439 -576 -712 -848 9625 381 244 107 -029 -166 -302 -439 -575 -712 -848 9875 382 245 109 -028 -165 -302 -438 -575 -712 -848 10125 384 246 11 -027 -164 -301 -438 -574 -711 -848 10375 385 248 111 -026 -163 -3 -437 -574 -711 -848 10625 386 249 112 -025 -163 -3 -437 -574 -711 -848 10875 387 25 113 -024 -162 -299 -436 -573 -711shy -848 11125 389 251 114 -023 -161 -298 -436 -573 -71 -848 11375 39 252 115 -022 -16 -298 -435 -573 -71 -847 11625 391 253 115 -022 -16 -297 -435 -572 -71 -847 11875 392 254 116 -021 -159 -297 -434 -572 -709 -847 12125 393 255 117 -02 -158 -296 -434 -572 -709 -847 12375 394 256 118 -019 -158 -296 -434 -571 -709 -847 12625 395 257 119 -019 -157 -295 -433 -571 -709 -847 12875 396 258 12 -018 -157 -295 -433 -571 -709 -847 13125 397 259 12 -017 -156 -294 -432 -57 -709 -847 13375 398 259 121 -017 -155 -294 -432 -57 -708 -847 13625 399 26 122 -016 -155 -293 -432 -57 -708 -846 13875 399 261 122 -016 -154 -293 -431 -57 -708 -846 14125 4 262 123 -015 -154 -292 -431 -569 -708 -846 14375 401 262 124 -015 -154 -292 -431 -569 -708 -846 14625 402 263 124 -014 -153 -292 -43 -569 -707 -846 14875 402 263 125 -014 -153 -291 -43 -569 -707 -846 15125 403 264 125 -013 -152 -291 -43 -569 -707 -846 15375 403 264 126 -013 -152 -291 -43 -568 -707 -846 15625 404 265 126 -012 -152 -291 -429 -568 -707 -846 15875 405 265 126 -012 -151 -29 -429 -568 -707 -846 16125 405 266 127 -012 -151 -29 -429 -568 -707 -846 16375 405 266 127 -011 -151 -29 -429 -568 -707 -846 16625 406 267 128 -011 -151 -29 -429 -568 -707 -846 16875 406 267 128 -011 -15 -289 -428 -568 -707 -845 17125 407 267 128 -01 -15 -289 -428 -567 -706 -845 17375 407 268 128 -01 -15 -289 -428 -567 -706 -845 17625 407 268 129 -01 -15 -289 -428 -567 -706 -845 17875 407 268 129 -01 -15 -289 -428 -567 -706 -845 18125 408 268 129 -01 -15 -289 -428 -567 -706 -845 18375 408 269 129 -01 -149 -289 -428 -567 -706 -845 18625 408 269 129 -001 -149 -288 -428 -567 -706 -845 18875 408 269 129 -001 -149 -288 -428 -567 -706 -845 19125 408 269 13 -001 -149 -288 -428 -567 -706 -845 19375 409 269 13 -001 -149 -288 -428 -567 -706 -845 19625 409 269 13 -001 -149 -288 -428 -567 -706 -845 19875 409 269 13 -001 -15 -288 -428 -567 -706 -845
114
FS Fresh Food Wan Simulation Output Including Anti-sweat Condenser Tube
INPUT PARAMETERS
Section Dimensions (mm) Hidth 4500 Length 2000 Depth 2960 Steel skin thickness 6500 Plastic skin thickness 2500
Mesh Geometry dx 2250 dy 2500 Number nodes in x-direction 20 Number nodes in y-direction 80 Number of steel skin nodes (including corner 00) 11 Steel nodes under the seal 2 to 10 Tube located at node 6
Steel skin conductivity (Him K) 5400 Foam insulation conductivity (Him K) 27000E-02 Plastic skin conductivity (Him K) 1500 Outside h (Hm2 K) 6870 Inside h (Hm2 K) 6700 Outside Temp (C) 2100 Inside Temp (C) 4000
OUPUT PARAMETERS
Number of iterations 602
10 Heat Flux Thru Hall (Hm2) 9132
Heat Transfer Along Metal Skin Under Seal node to node qm[Hm21 Qm[HI
2 3 -15052E+04 -2896 3 4 -15125E+04 -2910 4 5 -15198E+04 -2924 5 6 -15274E+04 -2939 6 7 3996 7688 7 8 3898 7500 8 9 3790 7292 9 10 3662 7045
Maximum difference () 1243
j qleft [HI qright [HI -1 -2957 7832 0 -92065E-02 -38838E-02 1 -77348E-02 -48044E-02 2 -51596E-02 -30284E-02 3 -32948E-02 -15188E-02 4 -1 9628E-02 -54201E-03 5 -98600E-03 16837E-03 6 -36442E-03 70ll8E-03 7 79586E-04 96757E-03 8 43478E-03 11452E-02 9 70118E-03 12340E-02 10 87877E-03 12340E-02
115
11 87879E-03 13228E-02 12 10564E-02 12340E-02 13 10564E-02 11452E-02 14 96759E-03 11452E-02 15 87877E-03 10564E-02 16 87879E-03 87877E-03 17 78999E-03 87877E-03 18 61238E-03 78999E-03 19 61240E-03 61237E-03 20 52359E-03 52358E-03 21 34598E-03 34598E-03 22 25719E-03 25717E-03 23 16838E-03 16839E-03 24 79586E-04 25 -98018E-04 26 -18681E-03 27 -27561E-03 28 -36442E-03 29 -54202E-03 30 -54202E-03 31 -7 1962E-03 32 -80842E-03 33 -8 9721E-03 34 -98602E-03 35 -10748E-02 36 -11636E-02 37 -12524E-02 38 -1 3412E-02 39 -1 4300E-02 40 -15188E-02 41 -1 5188E-02 42 -1 6076E-02 43 -16964E-02 44 -17852E-02 45 -1 7852E-02 46 -1 8740E-02 47 -19628E-02 48 -19628E-02 49 -19628E-02 50 -20516E-02 51 -21404E-02 52 -22292E-02 53 -22292E-02 54 -23180E-02 55 -23180E-02 56 -23180E-02 57 -24068E-02
79578E-04 -98018E-04 -1 8682E-03 -27561E-03 -45322E-03 -54202E-03 -71962E-03 -71962E-03 -8 9722E-03 -8 9722E-03 -10748E-02 -11636E-02 -12524E-02 -13412E-02 -14300E-02 -1 5188E-02 -16076E-02 -16964E-02 -16964E-02 -17852E-02 -18740E-02 -19628E-02 -20516E-02 -20516E-02 -21404E-02 -22292E-02 -22470E-02 -22381E-02 -22647E-02 -23358E-02 -23447E-02 -23802E-02 -24512E-02 -24690E-02
58 -23979E-02 -25223E-02 59 -24423E-02 60 -24246E-02 61 -24423E-02 62 -24779E-02 63 -25400E-02 64 -25400E-02 65 -25667E-02 66 -26199E-02 67 -26022E-02 68 -26111E-02 69 -26377E-02 70 -26022E-02 71 -26732E-02 72 -26821E-02 73 -26199E-02 74 -26643E-02
-25489E-02 -25755E-02 -25933E-02 -2 6199E-02 -26466E-02 -26643E-02 -26821E-02 -26910E-02 -27087E-02 -27265E-02 -27354E-02 -27443E-02 -27531E-02 -27620E-02 -27620E-02 -27709E-02
116
75 -26377E-02 -27709E-02 76 -26377E-02 -27709E-02 77 -26555E-02 -27709E-02 78 -26910E-02 -27620E-02 79 -26555E-02 -27620E-02
Qleft [ii] -3079 Qright [ii] 6756 Percent entering cabinet 1800
Fresh Food Nodal Temperatures (Condenser Tube)
x(mm) y(mm) 1125 3375 5625 7875 10125 12375 14625 16875 19125 21375
19875 126 1206 1154 1104 1055 1007 9608 9158 872 8294 19625 1259 1205 1153 1103 1054 1006 9602 9152 8715 8289 19375 1259 1205 1153 1102 1053 1006 9598 9149 8711 8285 19125 1259 1205 1153 1102 1053 1006 9596 9147 871 8284 18875 1259 1205 1153 1102 1053 1006 9596 9147 871 8284 18625 1259 1205 1153 1103 1054 1006 9599 915 8712 8286 18375 126 1206 1154 1103 1054 1007 9604 9154 8716 829 18125 1261 1207 1155 1104 1055 1007 9611 9161 8722 8295 17875 1263 1209 1156 1105 1056 1008 962 9169 873 8302 17625 1264 121 1158 1107 1058 101 9632 918 874 8311 17375 1266 1212 116 1109 1059 1011 9646 9193 8752 8322 17125 1269 1215 1162 1111 1061 1013 9663 9209 8766 8335 16875 1272 1217 1164 1113 1063 1015 9682 9226 8783 835 16625 1275 122 1167 1116 1066 1017 9704 9246 8801 8367 16375 1279 1224 117 1119 1069 102 9728 9269 8822 8386 16125 1282 1227 1174 1122 1072 1023 9755 9294 8845 8407 15875 1287 1231 1178 1126 1075 1026 9785 9322 887 843 15625 1292 1236 1182 113 1079 103 9818 9352 8898 8456 15375 1297 1241 1187 1134 1083 1034 9854 9385 8929 8484 15125 1302 1246 1192 1139 1088 1038 9892 9421 8962 8514 14875 1308 1252 1197 1144 1092 1042 9934 946 8998 8547 14625 1315 1258 1203 1149 1097 1047 9979 9502 9037 8583 14375 1322 1265 1209 1155 1103 1052 1003 9547 9078 8621 14125 1329 1272 1216 1162 1109 1058 1008 9595 9123 8662 13875 1337 1279 1223 1168 1115 1064 1014 9647 9171 8706 13625 1346 1287 1231 1176 1122 107 102 9703 9222 8753 13375 1355 1296 1239 1183 1129 1077 1026 9762 9277 8803 13125 1364 1305 1247 1191 1137 1084 1033 9824 9335 8856 12875 1374 1314 1256 12 1145 1092 104 9891 9396 8913 12625 1385 1325 1266 1209 1154 11 1047 9962 9462 8973 12375 1396 1335 1276 1219 1163 1109 1055 1004 9531 9037 12125 1408 1347 1287 1229 1173 1118 1064 1012 9605 9105 11875 1421 1359 1299 124 1183 1127 1073 102 9683 9176 11625 1434 1371 1311 1251 1194 1137 1082 1029 9765 9252 11375 1448 1385 1323 1263 1205 1148 1092 1038 9851 9332 11125 1462 1399 1336 1276 1217 1159 1103 1048 9943 9416 10875 1478 1413 135 1289 1229 1171 1114 1058 1004 9505 10625 1494 1429 1365 1303 1243 1184 1126 1069 1014 9598 10375 1511 1445 138 1318 1257 1197 1138 1081 1025 9696 10125 1528 1462 1397 1333 1271 121 1151 1093 1036 98 9875 1547 1479 1413 1349 1286 1225 1165 1106 1048 9908 9625 1566 1498 1431 1366 1302 124 1179 1119 106 1002
117
9375 1586 1517 145 1384 1319 1256 1194 1133 1073 1014 9125 1607 1537 1469 1402 1336 1272 1209 1147 1087 1027 8875 1629 1558 1489 1421 1355 129 1226 1163 1101 104 8625 1652 158 151 1441 1374 1308 1243 1179 1116 1054 8375 1676 1603 1532 1462 1394 1327 1261 1195 1131 1068 8125 17 1627 1555 1484 1415 1346 1279 1213 1148 1084 7875 1726 1652 1579 1507 1436 1367 1299 1231 1165 11 7625 1753 1678 1604 1531 1459 1389 1319 1251 1183 1116 7375 1781 1704 1629 1556 1483 1411 1341 1271 1202 1134 7125 1809 1732 1656 1581 1508 1435 1363 1292 1222 1152 6875 1839 1761 1684 1608 1533 146 1387 1314 1243 1172 6625 187 1791 1713 1636 156 1485 1411 1337 1264 1192 6375 1903 1823 1744 1666 1589 1512 1437 1362 1287 1214 6125 1936 1855 1775 1696 1618 1541 1464 1387 1312 1236 5875 197 1889 1808 1728 1649 157 1492 1414 1337 126 5625 2006 1923 1842 1761 1681 1601 1522 1443 1364 1285 5375 2043 196 1877 1795 1714 1633 1553 1473 1392 1312 5125 2081 1997 1914 1832 1749 1668 1586 1504 1422 134 4875 212 2036 1952 1869 1786 1704 1621 1538 1454 137 4625 2161 2076 1992 1909 1825 1741 1658 1573 1488 1403 4375 2203 2118 2034 195 1866 1782 1697 1611 1525 1437 4125 2246 2161 2077 1993 1909 1824 1738 1652 1564 1474 3875 229 2206 2123 2039 1955 1869 1783 1695 1606 1515 3625 2336 2253 217 2087 2003 1918 1831 1742 1651 1558 3375 2383 2302 222 2138 2055 197 1882 1793 1701 1606 3125 2432 2353 2273 2192 211 2026 1938 1848 1755 1658 2875 2482 2405 2328 225 217 2086 20 1909 1815 1715 2625 2533 2461 2387 2312 2234 2153 2067 1977 1881 178 2375 2586 2518 2449 2378 2304 2226 2142 2052 1955 1851 2125 264 2579 2516 2451 2381 2306 2225 2136 2039 1933 1875 2696 2642 2587 2529 2466 2396 2319 2232 2134 2026 1625 2753 2709 2664 2614 256 2497 2425 2341 2244 2133 1375 2811 278 2746 2708 2664 2611 2546 2468 2373 226 1125 2871 2854 2835 2811 278 2739 2685 2615 2524 2411 875 2932 2932 293 2923 2909 2885 2846 2787 2706 2595 625 2995 3014 3031 3045 3052 3049 3031 2989 2922 2824 375 3058 3098 3138 3175 3208 3234 3245 3223 3179 3109 125 3124 3185 3247 331 3373 3436 35 3483 3467 3451
x(mm) y(mm) 23625 25875 28125 30375 32625 34875 37125 39375 41625 43875
19875 7877 747 7071 6679 6294 5915 554 5168 4799 4432 19625 7872 7466 7067 6676 6291 5912 5538 5166 4798 4431 19375 7869 7463 7065 6674 6289 591 5536 5165 4797 443 19125 7868 7462 7063 6673 6288 591 5535 5165 4797 443 18875 7868 7462 7063 6673 6288 591 5535 5165 4796 443 18625 787 7463 7065 6674 6289 591 5536 5165 4797 443 18375 7873 7466 7067 6676 6291 5912 5537 5166 4797 443 18125 7878 747 7071 6679 6294 5914 5539 5167 4798 4431 17875 7884 7476 7076 6684 6298 5917 5542 5169 4799 4431 17625 7893 7483 7083 6689 6303 5921 5545 5172 4801 4432 17375 7903 7492 7091 6696 6309 5926 5549 5175 4803 4433 17125 7914 7503 71 6704 6316 5932 5553 5178 4806 4435 16875 7928 7515 7111 6714 6324 5939 5559 5182 4809 4436 16625 7943 7529 7123 6725 6333 5947 5565 5187 4812 4438 16375 796 7544 7137 6737 6343 5955 5572 5192 4815 444 16125 7979 7561 7152 675 6355 5965 558 5198 4819 4442
118
15875 8001 7581 7169 6765 6368 5976 5589 5205 4824 4445 15625 8024 7601 7188 6781 6382 5987 5598 5212 4829 4447 15375 8049 7624 7208 6799 6397 6 5608 522 4834 445 15125 8077 7649 723 6819 6414 6014 562 5229 484 4453 14875 8107 7676 7254 684 6432 603 5632 5238 4847 4457 14625 8139 7705 728 6862 6451 6046 5645 5248 4854 4461 14375 8174 7737 7308 6887 6472 6064 566 5259 4861 4465 14125 8211 777 7338 6913 6495 6083 5675 5271 4869 4469 13875 8251 7806 737 6941 6519 6103 5691 5283 4878 4474 13625 8294 7845 7405 6972 6545 6125 5709 5297 4887 4479 13375 834 7886 7441 7004 6573 6148 5728 5311 4897 4484 13125 8388 793 748 7038 6603 6173 5748 5326 4907 449 12875 844 7977 7522 7075 6634 62 5769 5343 4918 4496 12625 8495 8026 7566 7114 6668 6228 5792 536 493 4502 12375 8553 8079 7613 7155 6703 6258 5816 5378 4943 4509 12125 8615 8135 7663 7199 6741 6289 5842 5398 4956 4517 11875 868 8194 7716 7245 6781 6323 5869 5418 4971 4524 11625 8749 8256 7771 7294 6823 6358 5898 544 4986 4532 11375 8822 8322 783 7346 6868 6396 5928 5463 5002 4541 11125 8899 8392 7892 7401 6915 6435 596 5488 5018 455 10875 898 8465 7958 7458 6965 6477 5994 5514 5036 456 10625 9066 8542 8027 7519 7018 6521 6029 5541 5055 457 10375 9155 8624 81 7583 7073 6568 6067 557 5075 4581 10125 925 8709 8177 7651 7131 6617 6107 56 5095 4592 9875 9349 8799 8257 7722 7193 6669 6149 5632 5117 4604 9625 9454 8894 8342 7797 7257 6723 6193 5665 514 4617 9375 9564 8994 8431 7875 7325 678 6239 5701 5165 463 9125 9679 9098 8525 7958 7397 684 6288 5738 519 4644 8875 98 9208 8624 8045 7472 6904 6339 5777 5217 4659 8625 9927 9324 8727 8137 7551 6971 6393 5819 5246 4674 8375 1006 9445 8836 8233 7635 7041 645 5862 5276 4691 8125 102 9572 895 8334 7722 7115 651 5908 5307 4708 7875 1035 9706 907 844 7814 7192 6573 5956 5341 4726 7625 105 9846 9197 8552 7911 7274 664 6007 5376 4745 7375 1066 9994 933 867 8014 7361 671 6061 5413 4766 7125 1083 1015 947 8794 8121 7452 6784 6118 5452 4787 6875 1101 1031 9617 8925 8235 7548 6862 6178 5494 481 6625 112 1049 9773 9063 8356 765 6945 6241 5537 4834 6375 114 1067 9937 9209 8483 7757 7033 6308 5584 4859 6125 1161 1086 1011 9364 8618 7872 7126 638 5634 4887 5875 1183 1106 103 9528 8761 7993 7225 6456 5686 4916 5625 1207 1128 1049 9703 8914 8123 7331 6537 5743 4947 5375 1231 1151 107 9889 9076 8261 7443 6624 5803 498 5125 1258 1175 1092 1009 925 8409 7564 6717 5867 5015 4875 1286 1201 1116 103 9436 8567 7694 6816 5936 5053 4625 1316 1229 1142 1053 9637 8738 7833 6924 601 5094 4375 1349 1259 1169 1078 9853 8922 7983 7039 609 5138 4125 1384 1292 1199 1104 1009 912 8146 7164 6177 5186 3875 1422 1327 1231 1133 1034 9336 8321 7299 627 5237 3625 1463 1365 1266 1165 1062 957 8512 7445 637 5291 3375 1508 1407 1304 1199 1092 9824 8719 7603 6479 middot535 3125 1557 1453 1346 1237 1124 101 8943 7773 6595 5412 2875 1612 1504 1393 1278 116 104 9185 7956 6719 5478 2625 1673 1561 1444 1323 1199 1073 9446 8152 6851 5546 2375 1741 1624 1501 1373 1242 1108 9725 8359 6989 5617 2125 1818 1695 1565 1429 1289 1146 1002 8575 713 5687 1875 1906 1775 1636 149 1339 1186 1032 8792 727 5755 1625 2007 1868 1716 1556 1392 1227 1062 9001 7401 5818
119
1375 1125 875 625 375 125
2127 2271 2449 2679 2994 3436
1975 2103 226
2467 2776 3361
1807 1912 2032 2173 2333 2469
1629 1707 1788 1863 191
1868
1447 1501 1548 1575 1559 1454
1266 1301 1324 1324 1279 1163
109 1111 112
1107 1058 9548
9183 9311 934
9205 8813 8043
7514 7591 7611 7544 735
6956
5873 5918 5953 5988 6049 6199
F6 Freezer Wall Simulation Output Including Anti-sweat Condenser Tube
INPUT PARAMETERS
Section Dimensions (mm) Width Length Depth Steel skin thickness Plastic skin thickness
5600 2000 1580 6500 2500
Mesh Geometry dx dy Number nodes in x-direction Number nodes in y-direction Number of steel skin nodes (including corner 00) Steel nodes under the seal Tube located at node
2800 2500 20 80
11 2 to 10 6
Steel skin conductivity (Wm K)
Foam insulation conductivity (Wm K) Plastic skin conductivity (Wm K)
Outside h (Wm2 K) Inside h (Wm2 K) Outside Temp (C) Inside Temp (C)
5400 27000E-02 1500 6870 6410 2100 -1000
OUPUT PARAMETERS
Number of iterations 879
ID Heat Flux Thru Wall (Wm2) 1362
Heat Transfer Along Metal Skin Under Seal node to node qm[Wm2] Qm[W]
2 3 -15024E+04 -1543 3 4 -15111E+04 -1552 4 5 -15205E+04 -1562 5 6 -15310E+04 -1572 6 7 5828 5986 7 8 5690 5844 8 9 5535 5684 9 10 5348 5492
Maximum difference (Is) 1356
j qleft[W] qright[W] -1 -1566 5928
120
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63
0 -62085E-02 -31363E-02 -5 9522E-02 -40097E-02 -44286E-02 -30955E-02 -33621E-02 -21814E-02 -25242E-02 -1 4577E-02 -1 8767E-02 -9 6252E-03 -13815E-02 -58162E-03 -10387E-02 -31499E-03 -73398E-03 -1 6265E-03 -54353E-03 -10285E-04
-35309E-03 27805E-04 -23882E-03 65891E-04 -16265E-03 14208E-03 -1 24 55E-03 14207E-03 -48371E-04 14207E-03 -10285E-04 10398E-03 -10285E-04 10399E-03 -10281E-04 10398E-03 -48371E-04 65891E-04 -1 02 85E-04 27805E-04 -86465E-04 16377E-04 -48375E-04 -52182E-04 -86465E-04 -97886E-04 -1 2455E-03 -13979E-03 -1 7788E-03 -16645E-03 -19692E-03 -21597E-03 -24263E-03 -25786E-03 -30357E-03 -30357E-03 -33404E-03 -35309E-03 -3 7975E-03 -3 9879E-03 -41784E-03 -44450E-03 -45974E-03 -49402E-03 -50164E-03 -53592E-03 -54353E-03 -58162E-03 -58543E-03 -62733E-03 -62733E-03 -66923E-03 -66542E-03 -71493E-03 -70351E-03 -75303E-03 -74541E-03 -7 9111E-03 -77969E-03 -83301E-03 -81397E-03 -87491E-03 -85206E-03 -90919E-03 -88634E-03 -94728E-03 -92062E-03 -97775E-03 -95109E-03 -10158E-02 -98537E-03 -10463E-02 -1 0158E-02 -10768E-02 -1 04 63E-02 -11073E-02 -10692E-02 -11377E-02 -10996E-02 -11644E-02 -11225E-02 -1 1949E-02 -11492E-02 -12215E-02 -11758E-02 -12444E-02 -11949E-02 -12672E-02 -12177E-02 -12901E-02 -12368E-02 -13129E-02 -12596E-02 -1 3282E-02 -12748E-02 -1 351 OE-02 -1 2977E-02 -13701E-02 -13129E-02 -1 3853E-02 -13282E-02 -14005E-02 -1 3434E-02 -14158E-02 -13586E-02 -14310E-02 -1 3701E-02 -14463E-02
121
64 -1 3815E-02 -1 4577E-02 65 -1 392 9E-02 -14691E-02 66 -14005E-02 -14767E-02 67 -14120E-02 -14881E-02 68 -14196E-02 -14958E-02 69 -1 4272E-02 -15034E-02 70 -14310E-02 -15110E-02 71 -1 4386E-02 -1 5148E-02 72 -14424E-02 -15186E-02 73 -14463E-02 -15224E-02 74 -14501E-02 -1 5262E-02 75 -14501E-02 -1 5300E-02 76 -14539E-02 -15262E-02 77 -14539E-02 -15300E-02 78 -1 4539E-02 -15262E-02 79 -14501E-02 -1 5300E-02
Qleft [Wj -1653 Qright [Wj 5163 Percent entering cabinet 2380
Freezer Nodal Temperatures (Condenser Tube)
x(mm) y(mm) 14 42 70 98 126 154 182 210 238 266
19875 9606 8457 7334 6235 516 4107 3075 2064 107 00944 19625 9596 8448 7325 6227 5152 4099 3068 2056 1064 00882 19375 9591 8443 732 6222 5148 4095 3064 2053 106 00850 19125 9591 8443 732 6222 5147 4095 3064 2052 106 00847 18875 9596 8448 7325 6226 5151 4099 3067 2056 1063 00873 18625 9606 8457 7334 6235 5159 4106 3074 2062 1069 00928 18375 9621 8472 7347 6248 5171 4118 3085 2072 1078 01013 18125 9641 8491 7366 6265 5188 4133 3099 2085 109 01128 17875 9666 8514 7388 6287 5208 4152 3117 2102 1106 01272 17625 9696 8543 7416 6313 5233 4176 3139 2123 1125 01447 17375 9731 8577 7448 6343 5262 4203 3165 2147 1147 01652 17125 9772 8616 7485 6378 5295 4234 3194 2174 1173 01888 16875 9817 8659 7526 6418 5333 427 3228 2206 1202 02156 16625 9868 8708 7573 6462 5375 431 3265 224 1234 02455 16375 9924 8762 7624 6511 5421 4353 3306 2279 127 02786 16125 9985 8821 7681 6565 5472 4402 3352 2322 131 03149 15875 1005 8885 7742 6624 5528 4454 3401 2368 1353 03546 15625 1012 8954 7809 6687 5588 4511 3455 2418 1399 03976 15375 102 9029 7881 6755 5653 4573 3513 2472 145 04441 15125 1029 911 7958 6829 5723 4639 3575 253 1504 0494 14875 1038 9196 804 6907 5798 4709 3641 2592 1562 05474 14625 1047 9287 8128 6991 5877 4784 3712 2659 1623 06045 14375 1057 9385 8221 708 5962 4865 3787 2729 1689 06652 14125 1068 9488 832 7175 6052 495 3868 2804 1759 07297 13875 1079 9597 8424 7275 6147 504 3952 2884 1833 07981 13625 1091 9713 8535 738 6247 5135 4042 2968 1911 08704 13375 1104 9834 8651 7491 6353 5235 4136 3056 1993 09466 13125 1117 9962 8774 7608 6464 534 4236 315 208 1027 12875 1131 101 8902 7731 6581 5451 434 3248 2172 1112 12625 1146 1024 9037 786 6704 5568 445 3351 2268 1201 12375 1161 1038 9178 7995 6833 569 4566 3459 2369 1294
122
12125 1177 1054 9326 8136 6967 5818 4686 3572 2475 1392 11875 1194 107 9481 8284 7108 5951 4813 3691 2585 1494 11625 1211 1087 9642 8439 7256 6091 4945 3815 2701 1602 11375 1229 1104 981 86 7409 6237 5083 3945 2822 1714 11125 1248 1122 9985 8768 757 639 5227 4081 2949 1832 10875 1268 1141 1017 8943 7737 6549 5378 4222 3082 1954 10625 1288 1161 1036 9125 7911 6714 5534 437 322 2083 10375 1309 1181 1055 9314 8092 6887 5698 4524 3364 2217 10125 1331 1203 1076 9511 8281 7067 5868 4685 3514 2356 9875 1354 1225 1097 9716 8477 7254 6046 4852 3671 2502 9625 1378 1248 1119 9929 8681 7448 6231 5026 3835 2654 9375 1402 1271 1142 1015 8893 7651 6423 5208 4005 2813 9125 1428 1296 1166 1038 9113 7861 6623 5398 4183 2979 8875 1454 1321 1191 1062 9342 808 6832 5595 4369 3152 8625 1481 1348 1216 1086 9579 8308 7049 5801 4562 3333 8375 1509 1375 1243 1112 9826 8545 7275 6015 4764 3522 8125 1538 1403 127 1139 1008 8791 751 6238 4975 3719 7875 1568 1432 1299 1166 1035 9047 7755 6472 5196 3925 7625 1598 1462 1328 1195 1063 9314 8011 6715 5426 4142 7375 163 1494 1358 1224 1091 9591 8278 697 5667 4368 7125 1663 1526 139 1255 1121 9881 8556 7236 5919 4606 6875 1697 1559 1422 1287 1152 1018 8847 7514 6184 4855 6625 1731 1593 1456 132 1185 105 9151 7806 6462 5118 6375 1767 1629 1491 1355 1218 1083 9469 8113 6755 5394 6125 1804 1665 1527 139 1254 1117 9804 8435 7063 5686 5875 1842 1703 1565 1428 129 1153 1015 8774 7388 5995 5625 1881 1742 1604 1466 1329 1191 1052 9133 7732 6322 5375 1921 1782 1644 1507 1369 1231 1091 9511 8097 6669 5125 1962 1824 1686 1549 1411 1272 1133 9913 8485 7039 4875 2004 1867 173 1593 1455 1317 1176 1034 8899 7435 4625 2047 1912 1776 164 1502 1363 1223 108 9341 7859 4375 2092 1958 1823 1688 1552 1413 1272 1128 9816 8315 4125 2138 2005 1873 1739 1604 1466 1325 1181 1033 8807 3875 2184 2055 1925 1793 166 1523 1382 1238 1088 934 3625 2232 2106 1979 1851 1719 1584 1444 1299 1148 992 3375 2282 216 2037 1911 1783 1649 1511 1366 1214 1055 3125 2332 2215 2097 1976 1851 1721 1584 1439 1286 1125 2875 2384 2273 2161 2045 1925 1798 1663 152 1366 1202 2625 2436 2334 2229 212 2005 1883 1751 1609 1455 1288 2375 249 2397 2301 22 2093 1976 1849 1708 1554 1384 2125 2546 2463 2377 2287 2188 2079 1957 182 1666 1493 1875 2602 2532 2459 238 2293 2193 2079 1946 1793 16 17 1625 266 2605 2546 2482 2407 232 2215 2089 1939 176 1375 2719 2681 264 2592 2533 2461 2369 2253 2108 1928 1125 2779 2761 2739 271 2671 2618 2543 244 2305 2128 875 2841 2844 2844 2838 2822 2792 2739 2655 2535 2367 625 2903 293 2954 2974 2986 2984 2959 2899 2802 2658 375 2967 3018 3069 3117 316 3194 3209 3173 3108 3009 125 3032 3108 3186 3263 3342 3421 35 347 344 3412
x (nun) y (nun) 294 322 350 378 406 434 462 490 518 546
19875 -0865 -1811 -2743 -3663 -4573 -5474 -6368 -7257 -8141 -9022 19625 -0871 -1816 -2747 -3667 -4577 -5477 -6371 -7259 -8142 -9024 19375 -0874 -1819 -275 -3669 -4578 -5479 -6372 -726 -8143 -9024 19125 -0874 -1819 -275 -367 -4579 -5479 -6372 -726 -8144 -9025 18875 -0872 -1817 -2748 -3668 -4577 -5478 -6372 -7259 -8143 -9025
123
18625 -0867 -1812 -2744 -3664 -4574 -5476 -637 -7258 -8142 -9024 18375 -0859 -1805 -2738 -3659 -457 -5472 -6366 -7256 -8141 -9023 18125 -0848 -1796 -273 -3652 -4563 -5466 -6362 -7252 -8139 -9022 17875 -0835 -1784 -2719 -3642 -4555 -546 -6357 -7248 -8136 -9021 17625 -0819 -1769 -2706 -3631 -4546 -5451 -635 -7243 -8132 -9019 17375 -0800 -1752 -2691 -3618 -4534 -5442 -6342 -7237 -8128 -9017 17125 -0779 -1733 -2673 -3602 -4521 -5431 -6334 -7231 -8124 -9014 16875 -0754 -1711 -2654 -3585 -4506 -5418 -6323 -7223 -8119 -9012 16625 -0727 -1686 -2632 -3565 -4489 -5404 -6312 -7214 -8113 -9009 16375 -0697 -1659 -2607 -3544 -447 -5389 -6299 -7205 -8106 -9005 16125 -0664 -1629 -258 -352 -445 -5371 -6286 -7194 -8099 -9001 15875 -0627 -1596 -2551 -3494 -4428 -5353 -6271 -7183 -8091 -8997 15625 -0588 -156 -2519 -3466 -4404 -5332 -6254 -717 -8083 -8993 15375 -0545 -1522 -2484 -3436 -4377 -531 -6236 -7157 -8074 -8988 15125 -0500 -148 -2447 -3403 -4349 -5287 -6217 -7143 -8064 -8983 14875 -0451 -1436 -2408 -3368 -4319 -5261 -6197 -7127 -8053 -8977 14625 -0399 -1388 -2365 -3331 -4287 -5234 -6175 -7111 -8042 -8971 14375 -0343 -1338 -232 -3291 -4253 -5206 -6152 -7093 -803 -8965 14125 -0284 -1284 -2272 -3249 -4216 -5175 -6127 -7074 -8017 -8958 13875 -0221 -1228 -2221 -3204 -4177 -5143 -6101 -7054 -8004 -8951 13625 -0155 -1168 -2168 -3157 -4137 -5108 -6073 -7033 -7989 -8943 13375 -0085 -1104 -2111 -3107 -4093 -5072 -6044 -7011 -7974 -8935 13125 -0011 -1037 -2051 -3054 -4048 -5034 -6013 -6987 -7958 -8927 12875 0065 -0966 -1988 -2998 -4 -4993 -598 -6963 -7941 -8918 12625 01474 -0892 -1922 -294 -3949 -4951 -5946 -6937 -7924 -8909 12375 0233 -0815 -1852 -2878 -3896 -4906 -591 -6909 -7905 -8899 12125 03229 -0733 -1779 -2814 -384 -4859 -5872 -688 -7885 -8888 11875 0417 -0648 -1702 -2746 -3782 -481 -5832 -685 -7865 -8877 11625 05157 -0558 -1622 -2675 -372 -4758 -5791 -6819 -7843 -8866 11375 06189 -0464 -1537 -2601 -3656 -4704 -5747 -6785 -7821 -8854 11125 07269 -0366 -1449 -2523 -3589 -4648 -5701 -675 -7797 -8841 10875 08398 -0263 -1357 -2441 -3518 -4588 -5653 -6714 -7772 -8828 10625 09577 -0156 -126 -2356 -3444 -4526 -5603 -6676 -7746 -8814 10375 1081 -0044 -116 -2267 -3367 -4461 -555 -6636 -7718 -88 10125 121 00732 -1054 -2174 -3286 -4393 -5495 -6594 -769 -8785 9875 1344 01957 -0943 -2076 -3202 -4322 -5437 -655 -766 -8769 9625 1484 03238 -0828 -1974 -3113 -4247 -5377 -6504 -7628 -8752 9375 1631 04575 -0708 -1867 -302 -4169 -5314 -6456 -7596 -8734 9125 1784 05974 -0582 -1755 -2923 -4087 -5247 -6405 -7561 -8716 8875 1944 07436 -0450 -1638 -2822 -4001 -5178 -6352 -7525 -8697 8625 2111 08966 -0312 -1516 -2715 -3911 -5105 -6296 -7487 -8676 8375 2286 1057 -0167 -1387 -2604 -3817 -5028 -6238 -7447 -8655 8125 2469 1224 -0015 -1253 -2486 -3718 -4948 -6177 -7405 -8633 7875 2661 14 0143 -1111 -2363 -3614 -4863 -6112 -736 -8609 7625 2861 1584 031 -0962 -2234 -3504 -4774 -6044 -7314 -8584 7375 3072 1778 04856 -0806 -2097 -3389 -468 -5972 -7265 -8558 7125 3293 1982 06704 -0641 -1954 -3267 -4581 -5896 -7213 -853 6875 3526 2196 08652 -0467 -1802 -3138 -4476 -5816 -7158 -8501 6625 3771 2422 1071 -0283 -1641 -3002 -4366 -5732 -71 -847 6375 403 2661 1288 -0089 -1471 -2858 -4248 -5642 -7038 -8437 6125 4303 2914 1519 01168 -1291 -2705 -4124 -5547 -6973 -8402 5875 4593 3182 1763 03357 -11 -2542 -3991 -5445 -6904 -8365 5625 49 3467 2023 05686 -0896 -2369 -385 -5338 -683 -8326 5375 5227 3771 23 08169 -0678 -2185 -37 -5223 -6751 -8284 5125 5576 4095 2596 1082 -0446 -1988 -354 -5101 -6668 -8239 4875 5949 4442 2913 1366 -0198 -1778 -337 -4971 -6579 -8193 4625 635 4814 3254 167 00669 -1553 -3187 -4832 -6485 -8143 4375 6781 5215 3619 1997 03519 -1313 -2993 -4685 -6385 -809
124
4125 7246 5647 4014 2349 06577 -1055 -2785 -4528 -6279 -8036 3875 775 6116 444 2728 0986 -0780 -2565 -4362 -6168 -7978 3625 8299 6625 4902 3137 1339 -0486 -233 -4187 -6051 -7919 3375 8899 718 5404 3579 1717 -0173 -2082 -4003 -593 -7859 3125 9558 7787 595 4057 2122 01586 -1823 -3813 -5806 -7798 2875 1028 8455 6545 4573 2555 0508 -1553 -3618 -568 -7739 2625 1109 9192 7197 513 3014 0872 -1277 -3422 -5558 -7683 2375 12 1001 7912 5729 3497 1245 -1002 -3233 -5442 -7633 2125 1301 1093 8698 6373 3998 1618 -0739 -3059 -534 -7592 1875 1418 1196 9566 7058 4508 1975 -0503 -2914 -5262 -7564 1625 1552 1314 1053 778 5007 2292 -0319 -2818 -5218 -7554 1375 171 1452 116 8525 5462 2528 -0224 -2798 -5226 -7564 1125 19 1616 1281 9263 5815 2621 -0272 -2892 -5304 -7597 875 2136 182 1417 9928 5968 2477 -0537 -3151 -5478 -7651 625 244 2095 1569 1037 575 1953 -112 -3637 -5773 -7713 375 2845 2514 1726 1027 4873 0854 -2146 -4427 -6224 -7757 125 3384 3296 1814 8879 2904 -1057 -3745 -5602 -6885 -7725
F bull 7 Seal Simulation Source Code and Ouput
Program Seal
c This program simulates the heat transfer characteristics of an c idealized refrigerator door gasket The steady-state temperature c profile is determined numerically from a 2-D finite difference c code
cxxxxxxxxxxxxx Parameters and Variablesxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
integer NNNWnsurfijjlloopiters real emmissigmakhihoTiTodelsNN real depthareatolkair
parameter (N=6) parameter (NN=20) parameter (W=7) parameter (nsurf=4N-l) parameter (emmis=09) parameter (sigma=567e-8) parameter (k=03) parameter (kair=0026) parameter (hi=641) parameter (ho=687) parameter (Ti=1032) parameter (To=209) parameter (sNN=02) parameter (del=sNNNN) parameter (depth=10) parameter (area=deldepth) parameter (tol=10)
real x(Onsurf)y(Onsurf)len(ONOnsurf) real F(OnsurfOnsurf) real T(-lNN+lONN)radl(nsurf+l)rad(Onsurf) real Eb(Onsurf)bvector(nsurf+l)Amatrix(nsurf+lnsurf+l) real difasumqsumqtotqin(NN-l) real rlr2r3r4r5
125
real clc2c3c4c5c6c7
open (lfilemiddotGasketoutposition-rewind) open (2file=Gasket(q)outpositionmiddotrewind)
cxxxxxxxxxxxxx Determine Viewfactors xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
call Points(Ndelnsurfxy) call length(Ndelnsurfxylen) call Vfactor(NdelnsurflenF)
cxxxxxxxxxxxxx Resistors (C-m2W)
c Interior x- and y-directions rl=delk
c Exterior to outdoor ambient r2=1ho
c Exterior to indoor ambient r3-1hi
c Radiation r4=(1-emmis)emmis
c Air r5=delkair
xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
cxxxxxxxxxxxxx Guass-Siedel Iteration xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
c Begin massive loop to determine the steady-state temperature c distribution across the section First update the interior nodes c by considering the radiative heat transfer among the interior c surfaces The radiative transfer is updated by calling a routine c which computes the new radiosities every iteration Loop until c tolerance is met
c Initialize temperature field do 10 i=ONN
do 11 jONN T(ij)=50
11 continue 10 continue
do 15 j=ONN T(-1j)=250 T(NN+lj)=50
15 continue
c Set temperatures for row y=O and row y=NN do 20 i=ONN
T(iO)=fl(idel) T(iNN)=f2(idel)
20 continue
cxxxxxxxxxxxxx Begin Iteration xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
loop=l iters=l do while (loop eq 1)
c Update radiosities using new temps and update interior surface nodes
call Jsolver(FemmissigmaTNNNWnsurfradlradEb + bvectorAmatrix)
c interior corners cl=area (2rl) c2=arearl
126
c3=area (2rl) c4=arearl c5=arear4 c6=1(cl+c2+c3+c4)
T(WW)=c6(clT(W+lW)+c2T(W-lW)+c3T(WW+l)+ + c4T(WW-l)+c5(rad(0)-Eb(0raquo)
cl=arearl c2=area(2rl) c3=area(2rl) c4=arearl c5=arear4 c6-1(cl+c2+c3+c4) T(W+NW)=c6(clT(W+N+lW)+c2T(W+N-lW)+c3T(W+NW+l)+
+ c4T(W+NW-l)+c5(rad(N)-Eb(Nraquo) clarearl c2-area (2rl) c3-arearl c4=area(2rl) c5=arear4 c6=1(cl+c2+c3+c4) T(W+NW+N)=c6 (clT(W+N+lW+N)+c2T(W+N-lW+N) +c3T(W+NW+N+l)+
+ c4T(W+NW+N-l)+c5(rad(2N)-Eb(2Nraquo) cl=area(2rl) c2=arearl c3=arearl c4=area(2rl) c5=arear4 c6=1(cl+c2+c3+c4) T(WW+N)=c6 (clT(W+lW+N) +c2T(W-lW+N)+c3T(WW+N+l) +
+ c4T(WW+N-l)+c5(rad(3N)-Eb(3Nraquo)
c Interior surface y=W jl=l do 22 i=W+lW+N-l
cl=area(2rl) c2=area (2rl) c4=arearl c5=arear4 c7=arear5 c6=1(cl+c2+c4+c7) T(iW)=c6(clT(i+lW)+c2T(i-lW)+
+ c7T(iW+l)+c4T(iW-l)+c5(rad(jl)-Eb(jlraquo) jl=j1+1
22 continue
c Interior surface y=N+W jl=3N-l do 25 i=W+lW+N-l
cl=area(2rl) c2=area (2rl) c3=arearl c5=arear4 c7=arear5 c6=1(cl+c2+c3+c7) T(iW+N)=c6(clT(i+lW+N)+c2T(i-lW+N)+
+ c7T(iW+N-l)+c3T(iW+N+l)+c5(rad(jl)-Eb(jlraquo) jl=jl-l
25 continue
c interior surface x=W jl=4N-l do 30 j=W+lW+N-l
c2=arearl
127
c3=area (2rl) c4=area(2rl) c5-arear4 c7-arear5 c6-1(c2+c3+c4+c7) T(Wj)-c6(c7T(W+lj)+c2T(W-lj)+c3T(Wj+l)+
+ c4T(Wj-l)+c5(rad(jl)-Eb(jl))) jl=jl-l
30 continue
c interior surface x=W+N jl=N+l do 35 j-W+lW+N-l
cl=arearl c3=area(2rl) c4=area (2rl) c5-arear4 c7-arear5 c6-1(cl+c3+c4+c7) T(W+Nj)=c6(clT(W+N+lj)+c7T(W+N-lj)+c3T(W+Nj+l)+
+ c4T(W+Nj-l)+c5(rad(jl)-Eb(jl))) jl=j1+1
35 continue
c Interior air nodes do 37 j=W+lN+W-l
do 38 i=W+lN+W-l call sseqn(Tr5r5r5r5areaareaareaareaijNN)
38 continue 37 continue
c Solid nodes do 40 i=lNN-l
do 45 jlW-l call sseqn(TrlrlrlrlareaareaareaareaijNN)
45 continue do 50 j=W+N+lNN-l
call sseqn(TrlrlrlrlareaareaareaareaijNN) 50 continue 40 continue
do 55 j=WW+N do 60 i=lW-l
call sseqn(TrlrlrlrlareaareaareaareaijNN) 60 continue
do 65 i=W+N+lNN-l call sseqn(TrlrlrlrlareaareaareaareaijNN)
65 continue 55 continue
c Side boundaries do 70 j=lNN-l
call sseqn(Trlr2rlrlareaareaarea2area20jNN) call sseqn(Tr3rlrlrlareaareaarea2area2NNjNN)
70 continue
c Apply energy balance around the boundary of the gasket to determine c stopping criterium dif
dif-OO dif=dif+(area(2rl))(T(00)-T(01)) dif=dif+(area(2rl))(T(0NN)-T(0NN-l)) do 90 i=lNN-l
dif=dif+(arearl)(T(iO)-T(il)) dif=dif+(arearl)(T(iNN)-T(iNN-l))
128
90 continue dif=dif+(area(2r1raquo(T(NN0)-T(NN1raquo dif=dif+(area(2r1raquo(T(NNNN)-T(NNNN-1raquo
do 95 j=1NN-1 dif=dif+(arear2)(To-T(0jraquo dif-dif+(arear3)(Ti-T(NNjraquo
95 continue
print dif
c Stopping criterium if (dif It toll then
loop-O endif if (iters eq 10000) then
loop=O endif
iters=iters+1 end do
cxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx c Compute heat flux into the cabinet
qsum=OO asum=OO do 97 j=1NN-1
qin(j)=hiarea(T(NNj)-Ti) qsum=qsum+qin(j) asum=asum+area
97 continue qtot=qsumasum write(2) heat flux to interior [Wm2)qtot
do 100 j=NNO-l write(l) (T(ij)i=ONN)
100 continue
pause stop end
c----------------------------------------------------------------------shyc------~----------------------------------------------------------------
Subroutine Points(Ndelnsurfxy)
integer Nnsurfi real delincrx(Onsurf)y(Onsurf)
x(O)=OO y(0)=del2
c Points along y=O edge incr-OO do 10 i=lN
y(i)=OO x(i)=(del2)+incr incr=incr+del
10 continue
c Points along x=Ndel edge incr=OO do 20 i=N+12N
x(i)=Ndel
129
y(i)-(del2)+incr incr-incr+del
20 continue
c Points along y=Ndel edge incr=OO do 30 i=3N2N+l-1
y(i)-Ndel x(i)=(del2)+incr incr-incr+del
30 continue
c Points along x-O edge incr=OO do 40 i-nsurf3n+l-1
xli) -00 y(i)-laquo3del)2)+incr incr-incr+del
40 continue
return end
c----------------------------------------------------------------------shyc-----------------------------------------------------------------------
Subroutine length(Ndelnsurfxylen)
integer Nnsurfij real dellen(ONOnsurf)x(Onsurf)y(Onsurf)
c Special case surface 0 do 10 j=Onsurf
len(0j)=sqrtlaquox(0)-x(jraquo2+(y(0)-y(jraquo2) 10 continue
c Surfaces along y=O do 20 i=IN-l
do 30 j=Onsurf len(ij)=sqrtlaquox(i)-x(jraquo2+(y(i)-y(jraquo2)
30 continue 20 continue
c Special case surface N do 50 j=Onsurf
len(Nj)=sqrtlaquox(N)-x(jraquo2+(y(N)-y(jraquo2) 50 continue
return end
c----------------------------------------------------------------------shyc-----------------------------------------------------------------------
Subroutine Vfactor(NdelnsurflenF)
integer Nnsurfijjlj2 real dellen(ONOnsurf)F(OnsurfOnsurf)Lzero
c Determine viewfactors for special case of surface 0 Lzero=delsqrt(20) do 10 j=Onsurf
if (j eq 0) then F(Oj)=OO
elseif (j eq nsurf) then F(Oj)=(len(Oj)+len(10)-len(00)-len(ljraquo(2Lzero)
else F(0j)=(len(0j)+len(lj+l)-len(Oj+l)-len(ljraquo(2Lzero)
130
endif 10 continue
c Determine viewfactors for surfaces on edge y-O
do 20 i=IN-l do 30 j=Onsurf
if (i eq j) then F(ij)=OO
elseif (j eq nsurf) then F(ij)=(len(ij)+len(i+l0)-len(i0)-len(i+ljraquo(2de1)
else F(ij)=(len(ij)+len(i+lj+l)-len(ij+l)-len(i+ljraquo(2del)
endif sum=sum+F(ij)
30 continue 20 continue
c Determine viewfactors for all other surfaces do 40 iON-l
do 50 j=03N-l F(i+Nj+N)=F(ij)
50 continue do 60 j=3Nnsurf
F(i+Nj-3N)=F(ij) 60 continue
do 70 j=02N-1 F(i+2Nj+2N)=F(ij)
70 continue do 80 j=2Nnsurf
F(i+2Nj-2N)=F(ij) 80 continue
do 90 j=ON-l F(i+3Nj+3N)=F(ij)
90 continue do 100 j=Nnsurf
F(i+3Nj-N)=F(ij) 100 continue
40 continue
return end
c----------------------------------------------------------------------shyc-----------------------------------------------------------------------
Subroutine Jsolver(FemmissigmaTNNNWnsurfradlradEb + bvectorAmatrix)
integer NNNnsurfij real emmissigmaF(OnsurfOnsurf) real T(-INN+10NN)rad1(nsurf+l)rad(0nsurf) real Eb(0nsurf)bvector(nsurf+1)Amatrix(nsurf+lnsurf+l)surn
c Compute Eb for all surfaces do 10 i-ON-l
Eb(i)=sigma(T(i+WW) 4) Eb(i+N)=sigma(T(W+Ni+W)4)
10 continue incr=W+N do 20 i=0N-1
Eb(i+2N)=siqrna(T(incrW+N) 4) Eb(i+3N)=sigma(T(Wincr)4) incr=incr-1
20 continue
131
c Assign values to vector b do 30 i=Onsurf
bvector(i+l)-(emmis(l-emmisraquoEb(i) 30 continue
c Assign values to matrix A do 40 i-Onsurf
do SO j=Onsurf Amatrix(i+lj+l)--F(ij)
SO continue 40 continue
c Override diagonal terms do 60 i-Onsurf
sum-OO do 70 j-Onsurf
sum-sum+F(ij) 70 continue
Amatrix(i+li+l)-(emmis(l-emmisraquo+sum 60 continue
c Call routine to solve the set of equations for unknown JS call gaussy(Amatrixbvectorradlnsurf+l)
do 80 i=Onsurf rad(i)=radl(i+l)
80 continue
return end
c----------------------------------------------------------------------shyc-----------------------------------------------------------------------
Subroutine Gaussy(abxn) c
integer nkiimaxjkplusllplus real a(nn)b(n)x(n)amaxbtempatemp
+ aeon sum
do 28 k=l n amax=OO do 4 i=kn if(abs(a(ikraquo-abs(amaxraquo442
2 amax=a(ik) imax=i
4 continue if(abs(amax)-0le-15)101014
10 printO equations are not independent return
14 btemp=b(k) b(k)=b(imax) b(imax)=btemp do 18 j=kn
atemp=a(k j) a(kj)=a(imaxj)
18 a(imaxj)=atemp kplus=k+l if(k-n)222828
22 do 24 i=kplusn b(i)=b(i)-b(k)a(ik)a(kk) acon=a(ik) do 24 j=kn
24 a(ij)=a(ij)-a(kj)acona(kk) 28 continue
132
l=n 32 sum=OO
if(1-n)343838 34 lplus-1+1
do 36 j-lplusn 36 sum=sum+a(lj)x(j) 38 continue
x(l)-(b(l)-sum)a(ll) if(1-1)424240
40 1-1-1 goto 32
42 return end
c----------------------------------------------------------------------shyc-----------------------------------------------------------------------
Subroutine sseqn(TriplusriminusrjplusrjminusAiplus + AiminusAjplusAjminusijNN)
c This subroutine computes the temperature at node (ij) c given the temperatures of the surrounding nodes and c the resistances leading to these nodes
integer ijNN real T(-1NN+10NN)riplusriminusrjplusrjminus real AiplusAiminusAjplusAjminus real c1c2c3c4c5
c1=Aiplusriplus c2=Aiminusriminus c3=Ajplusrjplus c4=Ajminusrjminus c5=1(c1+c2+c3+c4)
T(ij)=c5(c1T(i+1j)+c2T(i-1j)+c3T(ij+1)+c4T(ij-1raquo
return end
c----------------------------------------------------------------------shyc----------------------------------------------------------------------shy
real function f1(x) c door BC
real x f1-18520 - 23413x
return end
c----------------------------------------------------------------------shyc----------------------------------------------------------------------shy
real function f2(x) c wall BC
real x f2=18128 - 3475x
return end
c----------------------------------------------------------------------shyc----------------------------------------------------------------------shy
133
Fresh Food Compartment Simulations Results
Run 1 The prescribed temperature profiles are
Wall 19203 - 1908 x Door 19203 - 1206 x
(x is in meters)
Outdoor Ambient = 210 degC Local Indoor Ambient = 1533 degC
Run 2 The prescribed temperature profiles are
Wall 18989 - 2024 x Door 19078 - 1326 x
(x is in meters)
Outdoor Ambient = 210 degC Local Indoor Ambient = 1496 degC
Run 3 The prescribed temperature profiles are
Wall 1895 - 1998 x Door 19053 - 1384 x
(x is in meters)
Outdoor Ambient = 208 degC Local Indoor Ambient = 1491 degC
Ayem~ Values Wall 1905 - 1977 x Door 1913 - 1384 x
(x is in meters)
Ave Outdoor Ambient = 209 degC Ave Local Indoor Ambient =1507 degC
Loss from Fresh Food == 10 W
134
Freezer Compartment Simulations Results
Run 1 The prescribed temperature profiles are
Wall 1821 - 343 x Door 18606 - 2354 x
(x is in meters)
Outdoor Ambient = 210 degC Local Indoor Ambient = 1029 degC
Run 2 The prescribed temperature profiles are
Wall 18182 - 3542 x Door 18544 - 2398 x
(x is in meters)
Outdoor Ambient = 210 degC Local Indoor Ambient = 1042 degC
Run 3 The prescribed temperature profiles are
Wall 17993 - 3452 x Door 18411 - 2272 x
(x is in meters)
Outdoor Ambient = 208 degC Local Indoor Ambient = 1024 degC
Ayera~e Values Wall 18128 - 3475 x Door 18520 - 23413 x
(x is in meters)
Ave Outdoor Ambient = 209 degC Ave Local Indoor Ambient = 1032 degC
Loss from Fresh Food = 157 W
135
LIST OF TABLES
Page
31 One-dimensional Model Parameters 8 32 Results from One-dimensional Load Analysis 10
41 Thermopile Output 16 42 Experimental Determination of qwall and qdoor 20 43 Experimental Results from Mullion Analysis 24 44 Experimental Results from Heater Analysis 26 45 Miscellaneous Loads 27
51 Wall Simulation Input 30 52 Input Values 32 53 Wall Simulation Results 33 54 Wall With Condenser Tube Simulation Results 36 55 Seal Simulation Input 42 56 Seal Simulation Results 43
61 Comparison of Simulation and Experimental Values for qwall and qdoor 48 62 Overall Cabinet Loads 51
A1 Average Fumed Silica Conductivity for Various Bulk Densities 63 A2 Average Fumed Silica Diffusivity for Various Bulk Densities 64
E1 Thermopile Raw Data 82
F1 Model Resistors 92
V1l
LIST OF FIGURES
Page 11 Door Seal Region Cross Section 3 12 Mullion Region Cross Section 4
31 Model Used To Calculate One-dimensional Load 7
41 SteelSkin Temperature Profile Thermocouple Placement 12 42 Steel Skin Temperature Plot for Fresh Food Compartment 13 43 Steel Skin Temperature Plot for Freezer 14 44 Thermopile Test Apparatus 15 45 Thermopile Placement ~ 16 46 Thermocouple Drag Test Apparatus 17 47 Drag Profiles (Fresh Food) 18 48 Drag Profiles (Freezer) 19 49 Heat Flow Paths in Mullion 21 410 Mullion Face Plate Cross Section 22 411 Mullion Temperature Profile 23 412 Electric Heater Location 25 413 Mullion Temperature Profile With Heater On (Center) 26
51 Wall Heat Conduction Model Sketch 29 52 Non-adiabatic Door Seal 31 53 Fresh Food Wall Temperature Distribution 34 54 Freezer Wall Temperature Distribution 35 55 Tube Location for Simulation 36 56 Fresh Food Wall Temperature Distribution
Including Warm Anti-sweat Tube 37 57 Freezer Wall Temperature Distribution
Including Warm Anti-sweat Tube 38 58 Load Due to Condenser Tube for Various Tube Placements 39 59 ~ercentage of Heat Entering Cabinet for Various Tube Placements 39 510 Seal Simulation Mesh Layout 40 511 Seal Cavity Mesh Details 41 512 Seal Temperature Distribution (Fresh Food) 44 513 Seal Temperature Distribution (Freezer) 45
61 Refrigerator System Load Graph 46 62 Cabinet Loads Graph 47
A1 Fumed Silica Test Apparatus 59 A2 Fumed Silica Test Facility Schematic 60 A3 Time vs Temperature for Unpacked Run 61 A4 Natural Log Time vs Temperature for Unpacked Run 62 A5 Conductivity vs Bulk Density 63 A5 Diffusivity vs Bulk Density 64
viii
LIST OF FIGURES (CONTINUED)
Page
C1 Location of Anti-sweat Devices and Overall Dimensions of Test Refrigerator 73
C2 Fresh Food Compartment Interior Dimensions 74 C3 Fresh Food Door75 C4 Freezer Interior Dimensions 76 C5 Freezer Door76
D1 Data Acquisition and Control System 78
E1 Steel Skin Temperature Plot for Fresh Food Compartment (Run 2) 79 E2 Steel Skin Temperature Plot for Fresh Food Compartment (Run 3) 80 E3 Steel Skin Temperature Plot for Freezer (Run 2) 80 E4 Steel Skin Temperature Plot for Freezer (Run 3) 81 E5 Mullion Temperature Profile Run 2 (Heater Off) 84 E6 Mullion Temperature Profile Run 3 (Heater Off) 85 E7 Mullion Temperature Profile Run 4 (Heater Off) 85 E8 Mullion Temperature Profile Run 5 (Heater Off) 86 E9 Mullion Temperature Profile Run 2 (CenterHeater On) 87 E10 Mullion Temperature Profile Run 3 (CenterHeater On) 88 E11 Mullion Temperature Profile Run 1 (LeftHeater On) 88 E12 Mullion Temperature Profile Run 2 (LeftHeater On) 89 E13 Mullion Temperature Profile Run 3 (LeftHeater On) 89 E14 Mullion Temperature Profile Run 1 (RightHeater On) 90 E15 Mullion Temperature Profile Run 2 (RightHeater On) 90 E16 Mullion Temperature Profile Run 3 (RightHeater On) 91
F1 Generic Nodal Resistor Network 92
IX
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I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I
I I I I I I I I I I I I I I I I I I I I I I
1 INTRODUCTION
New regulations recently announced by the Department ofEnergy call for substantial
energy efficiency increases for household appliances by 1993 The refrigerator is of
particular interest since it is the largest household consumer of electricity and accounts for a
large part of the 8 of the electricity used in the US for food-cooling both residential and
commercial In addition to efficiency standards regulations are being imposed on the use
of CFCs completely banning their use by the year 2000 (Braswell 1988)
The objective of this thesis is to present an analysis of all heat transfer paths from the
surroundings to the interior food compartments of the refrigerator under closed door
conditions Both experimental and numerical methods are used as a means to determine the
overall cabinet load as well as the load due to each pathway The study is focused on a
particular unit for practical purposes However the methods implemented may be applied
to any make or model to aid in the search for high efficiency cabinets
All loads determined in this study are strictly cabinet loads and not the loads seen by the
refrigerator system The thermal load on the cabinet is comprised of three main parts (i)
the load due to the one-dimensional heat transfer through the walls and doors to the food
compartments away froin the edges (ii) the load due to edge effects that is heat transfer
into the food storage compartments via paths around the perimeter of the cabinet aperture
and (iii) other miscellaneous sources
(11)
The determination of qlD is straightforward and is discussed in detail in Chapter 3 The
edge load must be broken down into several parts for examination
qedge = qwall + qdoor + qseal + qrnullon + qtubeave (12)
where
qwall heat input due to conduction along the wall steel flange
qdoo heat input due to conduction along the door steel flange
qseal heat conduction directly through the door seal
1
heat input due to conduction in the mullion region with the additional input from an anti-sweat heater
qtubeave heat input due to cabinet anti-sweat condenser tube averaged over the cycle time
heat input due to cabinet anti-sweat condenser tube
heat input due to conduction in the mullion region electric heater off
It is assumed that an electric anti-sweat heater in the mullion region is in use for the entire
cycle The test unit chosen for this study required this region to be heated almost
continually to eliminate condensation This load is represented by qmulloo in Eq (12)
The load qmulloff is due to heat conduction to the interior compartments at the mullion
region when the electric heater is off Although this value does not appear in the edge load
definition it is still important to detennine for sake of comparison with the value of
qmulloo The load due to the presence of an anti-sweat condenser loop around the aperture
of the cabinet is defmed as qtube Since this load is present for the on cycle only it must be
integrated over the cycle time to be included in Eq (12) hence the tenn qtubeave
The tenn qroisc is expressed as
qmisc = qfanave + qdefrostave + qcompave (13)
where
qfanave heat input from the evaporator fan averaged over the cycle time
qdefrostave heat input from the defrost heaters averaged over defrost cycle time
qcompave heat input from elevated exterior walls near the running compressor
Figure 11 is a cross sectional drawing of the door seal area of the test refrigerator
examined to detennine qwalI qdoor and~ The figure includes materials and their
properties taken from Incropera and Dewitt (1985)
2
400 ~I-I~ 065~
065 Only dimension that is different for the freezer
200
kltWIm-K)
Outer Steel Skin 540 312~ Polyurethane Wall Insulation 0027 0015- Inner Plastic Skin 015 009~
~ Rubber Gasket 03 017fm1I ~ ~ Glass Fiber Door Insulation 004 0023
All dimensions in millimeters
1 in= 254mm
Fig 11 Door Seal Region Cross Section
3
Figure 12 is a drawing of the mullion region cross section of the test refrigerator examined
to detennine ltlmullon and ltlmulloff
FREEZER
Freezer Gasket
Fresh Food Gasket
FRESH FOOD COMPARTMENT
Fig 12 Mullion Region Cross Section
The remainder of this thesis is devoted to the analysis of the closed door cabinet loads and
the experimental and numerical techniques used for their detennination
An experimental investigation of fumed silica as an alternative insulation for the refrigerator
is presented in Appendix A Although this appears to be a departure from the main topic
a relation exists The desire of higher efficiency requires a search for equal if not better
cabinet insulations that do not incorporate the use of ozone damaging CFCs Testing is
done to detennine the thennal conductivity and diffusivity of fumed silica for several
densities
4
2 LITERATURE REVIEW
The new energy standards imposed by the Department ofEnergy have sparked research in
the area of refrigerator efficiency and alternative refrigerants A study by Turiel and
Heydari (1988) focused on several ways to improve the efficiency of refrigerator-freezers
and freezers
Various classes for the study were chosen however the paper presents extensive results for
the most common variety a top-mounted automatic defrost refrigeratorfreezer The
design options considered were those changes that can be incorporated into the existing
refrigerator design Two types of improvements are noted (i) changes that increase energy
efficiency by decreasing the heat transfer into the cabinet and (ii) changes that increase the
efficiency by reducing auxiliary electricity use or improving the refrigeration system Type
(i) changes include Foam insulation substitution increased insulation thickness double
door gaskets improved foam insulation evacuated insulation panels and reduced heat load
of through-the-door feature Type (ii) changes include High efficiency compressor
substitution adaptive defrost fan and fan motor improvement anti-sweat heater switch
increased evaporator surface area hybrid evaporator enhanced heat transfer surfaces
mixed refrigerants improved expansion valve fluid control valve two-compressor system
use of natural convective currents and location of compressor condenser and evaporator
fan motor
Turiel and Heydari used a model developed by Little (1982) to carry out the energy use
simulations This model is a steady-state energy use simulation which computes the heat
leakage to the cabinet and then determines the energy needed to maintain the interior
ambient temperatures dictated by the OOE test procedure Turiel and Heydari present the
energy consumption figures for a 18 cubic foot top-mounted automatic defrost
refrigeratorfreezer as a baseline case They find that 74 of the total energy is accounted
for by the compressor 11 is for the anti-sweat heaters 10 is for the fans and 5 is
for the defrost heaters for a total of 947 kWhyr Also about 10 of the compressor
energy use is for the removal of internal heat generated by the evaporator fan motor defrost
heater and anti-sweat heaters
Several subsequent simulations were performed each time adding a design option that was
projected to improve efficiency The improvement levels were added cumulatively and
results were given on compressor run time heat leakage rate into the cabinet compressor
5
power demand at the operating point fan motor operating power for the evaporator and
condenser fans anti-sweat heater power and total daily and annual energy consumption
The goal here was to achieve by the last level of improvement the minimum energy
consumption that is technologically feasible One important fmding for all product classes
tested the highest efficiency was obtained by the use of evacuated panels in the planar
walls For example for the top-mounted automatic defrost unit the minimum energy use
was 515 kWyr
Finally an energy usevolume relation was developed from a linear regression obtained
from simulation results The resulting fit was shown as
Energy Use = Cl + C2Adjusted Volume
The constant Cl indicates the direct energy use to remove the cabinet loads associated with
the fan motors and heaters The slope C2 is an indicator of the rate of change ofenergy use
with a change in the adjusted volume This value reflects the rate of cabinet heat gain The
adjusted volume is the volume of the fresh food compartment plus 163 times the volume
of the freezer Turiel and Heydari produced a series of regressions for all of the defined
levels of design improvements allowing easy comparison at a specific adjusted volume
6
3 ONE-DIMENSIONAL WALL AND DOOR LOADS
In this section the overall steady cabinet load is calculated without considering the addition
of edge loading This load qlD is dermed as the heat transfer from the exterior
environment to the interior of the refrigerator under nonnal closed-door operating
conditions through four primary conductive paths (i) fresh food compartment walls (ii)
freezer walls (iii) fresh food door and (iv) freezer door In a later chapter the load due to
edge loading will be examined more closely
31 One-dimensional Heat Transfer Model
The steady conductive heat transfer through the walls of the refrigerator cabinet is
computed using a simple computer program written by Qausing (1983) This program
estimates inside and outside effective heat transfer coefficients using a flat plate natural
convection correlation Using these coefficients and the material properties and dimensions
of the wall insulation the one-dimensional heat transfer through the cabinet walls is
approximated for the fresh food and freezer compartments Figure 31 shows the
resistances and boundary conditions use in the model
Fig 31 Model Used To Calculate One-dimensional Load
7
The model provides flexibility for varying several parameters This allows application to
various types of refrigerator walls and doors Table 31 lists the input and output
parameters for the model The source code of the simulation along with the output for
completed runs are included in Appendix B
Table 31 One-dimensional Model Parameters
Input Parameters
To K (F) Room ambient temperature
Ti K (F) Interior ambient temperature
LiDs m (ft) WalVdoor insUlation thickness
kiDs Wm-K (Btuhr-ft-F) WalVdoor insulation thermal conductivity
A m2 (ft2) Cabinet surface area
Output
beo Wm2K (Btuhr-ft2_F) Exterior convective heat transfer coefficient
bei Wm2K (Btuhr-ft2-F) Interior convective heat transfer coefficient
hro Wm2K (Btuhr-ft2_F) Exterior effective radiative heat transfer coefficient
hri Wm2-K (Btuhr-ft2_F) Interior effective radiative heat transfer coefficient
qlD W (Btuhr) Heat transfer rate through specified section
32 Determination of Effective Heat Transfer Coefficients
The simulation developed automatically estimates the inside and outside effective heat
transfer coefficients This effective value is the sum of the convective and radiative
components which are defined below
The radiative heat transfer coefficients are computed iteratively using eqs (31) and (32)
assuming (i) gray walls at temperatures T wi or Two with emissivities poundi and Eo (ii) black
surroundings at Ti or To and (iii) walls can see surroundings only
(31)
(32)
8
The convective heat transfer coefficients are estimated from a flat plate natural convection
correlation developed by Clausing (1983) In the laminar regime (Ra lt 1()9) the Nusselt
number based on the film temperature is given by Eq (33)
NUf = 052 Ra4 (33)
For the turbulent regime (Ra ~ 109) the Nusselt number becomes
NUf = 009 Raf3 (34)
where in both cases
Tw+T_ Film temperature T f == 2
Lc == Vertical surface characteristic length g == Gravitational acceleration f3 == Thermal expansion coefficient v == Kinematic viscosity Tw == Vertical wall surface temperature T_ == Outsideinside ambient temperature
kf == Air thermal conductivity
The film temperature characteristic length Nusselt number and Rayleigh number will
have different values for the inside surface compared with the outside surface of the
cabinet Therefore the inside and outside convective heat transfer coefficients are
determined separately from eqs (35) and (36)
(35)
- NUfo kfohco - (36)Leo
9
33 Results
The four primary regions analyzed are (i) the fresh food compartment walls (ii) fresh food
door (iii) freezer walls and (iv) the freezer door The values for the input parameters
ltLins kins A) are taken from a full-size unit that is used for the experimental analysis
presented in Chapter 4 The room temperature is used for the model parameter To Also
the fresh food ambient Tee and the freezer ambient Tfz are substituted for Ti when
suitable in order to closely simulate real operating conditions The results are given in
Table 32
Table 32 Results From One-dimensional Load Analysis
Input
Section TooC eF)
Tj degC eF)
Lins m (ft)
kins Wm-K (Btuhr-ft-OF)
A m2 (fi2)
Fresh Food 21 4 0045 0027 242 Walls (698) (392) (0148) (0015) (2605)
Fresh Food 21 4 0040 0040 089 Door (698) (392) (0131) (0023) (958)
Freezer 21 -10 0056 0027 110 Walls (698) (-140) (0184) (0015) (1184)
Freezer 21 -10 0040 0040 034 Door (698) (-140) (0131) (0023) (366)
Output
Section hco Wm2-K cBtuhr-ft2-Fl
hro Wm2-K iJtuhr -ft2-Fgt
hci Wm2-K (Btuhr-ft2-F)
hri Wm2-K 1Btuhr-ft2-F)
qlD W (Btuhr)
Fresh Food 130 544 198 461 209 Walls (23) (96) (35) (81) (713)
Fresh Food 144 542 218 463 117 Door (25) (95) (38) (82) (399)
Freezer 143 542 226 397 143 Walls (25) (95) (39) (70) (488)
Freezer 164 538 259 400 81 Door (29) (94) (46) (70) (276)
herro =687 Wm2 K (121 Btulhr-ft2-OF) Total qlD =550 W herrrr = 670 Wm2 K (118 Btulhr-ft2_0F) (1876 Btuhr)
herrrz = 641 Wm2 K (113 Btulhr-ft2-OF)
The load for our operating conditions is 550 W (1876 Btuhr) Once again this quantity
does not reflect the total cabinet load on the refrigerator cabinet Edge effects are analyzed
in detail in the following chapters Another important result is the values for the effective
10
inside and outside heat transfer coefficients which are simply the sum of the convective
and radiative components The outside coefficient is heffo the fresh food coefficient is
heffff and the freezer coefficient is hefffz These numbers are used whenever film
coefficients are needed for computations
11
4 EXPERIMENT AL ANALYSIS
This section presents an experimental study performed on a full-size household
refrigerator In Chapter 3 we defined the load due to heat transfer through the walls and
doors of the cabinet as qlD The purpose of this experimental analysis is to quantify qwalh
qdoor qmulloff and Qrnullon and Qmisc Three types of tests are performed to accomplish
this task Descriptions of each are presented separately in the sections that follow
41 Temperature Profile Measurements
The refrigerator is instrumented with many thermocouples in various key areas to give
temperatures across the steel skin and to compare and verify the thermopile tests outlined
in the next section The four primary paths along the steel flange that are examined are the
wall-side fresh food door-side fresh food wall-side freezer and the door-side freezer
Five Type T 36 AWG thermocouples are placed along the skin for each path Figure 41
is a detailed drawing of the location of the thermocouples
Wall side TICs Door side TICs with 5 mm spacing with 5 mm spacing
Fig 41 Steel Skin Temperature Profile Thermocouple Placement
The wire leads are oriented so they run perpendicular to the temperature gradient so as to
reduce any effects of conduction along the wire to the bead The temperature data are fed to
the data acquisition system Each channel is a thermocouple input and is scanned at a rate
of 5 times a second The data are smoothed automatically by the software in blocks of 10
12
points for an average temperature every 2 seconds A full description of the data
acquisition and control system is provided in Appendix D
Data are collected for several runs to provide a good base to detennine average values since
the test conditions vary slightly from run to run To get a good measurement of the
temperature profIles along the steel flange the unit is shut off at the beginning of the run
and allowed to drift to quasi-steady conditions The presence of a large amount of thennal
mass (see Appendix C) within the refrigerator provides for a stable interior ambient
temperature during data collection The outer ambient is controlled by the room thennostat
which keeps the laboratory at a constant temperature to within plusmn1degC
Figure 42 is an example plot of a run that gives the temperature profIles along the steel
skin on the wall-side and door-side for the fresh food compartment
193
192
G 191 ~
i 19
middot5 189F
188
Run I iii --0 - Door Profile
~Imiddotmiddotmiddotmiddotmiddotmiddotmiddott 0 Wall Profue
i ~ i - - T =19273 - 001206x i i-- door i If ~
=-r~r==L~r=I ~ I +~~=~~~~~~~~~ middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot
Outdoor Ambient = 210 degC Fresh Food Ambient =48 degC
187-+----+----J------I----+---~
o 5 10 15 20 25
x (mm) 1 in= 254 mm
Fig 42 Steel Skin Temperature Plot for Fresh Food Compartment
The dashed line represents a linear least-squares fit for the door data and the solid line is the
corresponding fit for the cabinet wall data Each data point in the plot represents the
average temperature at that point over a period of time at quasi-steady conditions
Similarly Figure 43 is a plot of the temperature profIles for the freezer
13
186
184
a 182
~
i 18
5 178~
176
174
Run 1 t-- 1 1 --0 - Door Profde
P~P1 0 Wall Profile
- -LLl--=-+--shy- - Tdo = 18606 - O02354x i
or ~
=c==-rc1 1 ltb 1 ~
~~r--r- -r---shy0 5 10 15 20 25
x (mm) 1 in= 2S4mm
Fig 43 Steel Skin Temperature Plot for Freezer
A total of six separate runs were perfonned three for the fresh food compartment and three
for the freezer Plots for the other runs are located in Appendix E
From the figures above for the fresh food compartment the slope on the wall-side is
slightly steeper than the slope on the door-side In fact this trend is seen for all the runs
Therefore the heat conduction along the metal skin into the cabinet along the wall is
somewhat greater than that of the door For the freezer the slopes are nearly equal hence
the heat conduction along the wall skin and the door skin are nearly the same
42 Thermopile Testing
Another simple but important test is the use of a thennopile to measure the average
temperature difference at various locations on the steel flange regions of the unit Figure
44 is a schematic of the thennopile test set-up The thennopile is constructed from 36
AWG copperconstantan thennocouple wire
14
-
CopperConstan$t Junctions 285 mPt
IOmm
10mmThermopile
IOmm
Digital Multimeter
1 in= 254mm
Fig 44 Thermopile Test Apparatus
Five junctions are used for the fresh food compartment and three for the freezer The
junctions are mounted 10 mm (039 in) apart from one another along the steel skin beneath
the door seal Figure 45 is a detailed drawing of the lateral location of the thermopile
junctions
15
1 in =254 mm
Fig 45 Thermopile Placement
The thennopile provides an average temperature difference across the junctions The
output voltage must frrst be divided by the number of pairs of junctions and then translated
into a temperature difference using a referencing chart for the thennocouple wire Table
41 is a summary of the results from these tests The output voltages are read accurately to
within plusmn0002 mV The raw data and data reduction procedure are given in Appendix E
Table 41 Thermopile Output
Test Conditions Fresh Food aT Freezer aT TodegC
(OF) TffoC
(OF) Tfzoc
(OF) aTwallff degC
(Of) aTdoorffoc
(OFgt aTwallfzoC
(Of) aTdoorfzoC
(OFgt
1 210 (698)
48 (406)
-88 (162)
026 (047)
024 (043)
037 (067)
041 (074)
2 210 (698)
37 (387)
-87 (163)
027 (049)
026 (047)
038 (068)
040 (072)
3 208 (694)
37 (387)
-93 (153)
027 (049)
026 (047)
038 (068)
040 ( 072)
Average Values 209 (696)
40 (392)
-90 (158)
0267 (0481)
0253 (0455)
0377 (0679)
0403 (0725)
43 Thermocouple Drag Testing
One final technique applied is thennocouple drag testing This is a more qualitative method
to supply insight into what exactly is happening when the compressor is pumping wann
16
refrigerant through the anti-sweat tube that lines the perimeter of the cabinet aperture The
main objective of this test is not to give accurate temperature proftle infonnation but
instead to detennine the placement of the condenser tube This is needed as an input for
the numerical simulation of this region The reason that the temperature are not accurate is
the fact that the thermocouple is being dragged across a surface where good thermal contact
may not occur and significant energy may be generated Figure 46 is a schematic of the
apparatus used for drag testing
Power Supply
Data Acquisition System
Outer Metal Skin
Potentiometer
Inner Plastic Skin
Condenser Tube
Fig 46 Thermocouple Drag Test Apparatus
This device is quite simple yet very effective The type T 36 AWG thennocouple begins
at the interior boundary of the steel skin beneath the seal on the wall-side of the cabinet
The potentiometer is turned by hand moving the thennocouple oqtward along the skin
The temperature and location are stored simultaneously this way The thennocouple is kept
17
pressed against the steel flange by the seal The linear translation of the thennocouple is a
function of the output voltage Voutbull
s = 2mllT Vout (41)Yin
r =radius of potentiometer post =30 mm (012 in)
nT = total number of turns of potentiometer = 10
Vin = input voltage = 05 V
Vout = output voltage
Drag tests are run on the wall steel skin for both the fresh food compartment and the
freezer Runs are perfonned at four separate times the first being when the compressor
turns on Figure 47 is a plot of the drag proflles across the wall-side skin in the fresh food
compartment Figure 48 is a plot of the profiles in the freezer compartment The same
trends are generally seen for both regions The freezer profiles are simply shifted down in
temperature values as expected The temperature peak seems to move through time to
settle near the center of the flange region under the seal
31
30
29
G
i 28~
27
26~
25
24
23
e
Ji ~ i i i 1middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotlmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddoti~~
---l- Time 4
o Time 2 rr
i
0 5 10 15 20 x (mm)
Fig 47 Drag Profiles (Fresh Food)
18
26~--------+---------~-------4--------~
i ~
Time 1 24
22
20
18
16~~------+---------~-------4--------~
4 __
~~Time3
middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot_middotmiddot_middotmiddotimiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot
Outer Seal Edge o
o 5 10 15 20
x (mm)
Fig 48 Drag Profiles (Freezer)
44 Experimental Determination of qwall and qdoor
The results from the temperature profile and thennopile testing are used to detennine qwall
and qdoor according to the following defmitions
qwall = qwallff + qwallfz (42)
(43)
Where qwal1ff = heat conduction along wall-side fresh food compartment steel flange
qwallfz = heat conduction along wall-side freezer compartment steel flange
qdoorff = heat conduction along door-side fresh food compartment steel flange
qdoorfz = heat conduction along door-side freezer compartment steel flange
The trends derived from the fixed profiles exhibit generally good agreement with the
temperature differences seen by the thennopile For the fresh food compartment the
thennopile displays a slightly larger AT than what is seen in the profiles and both give a
19
slightly larger temperature difference for the wall-side compared with the door-side For
the freezer the temperature differences match closely on the wall-side however the doorshy
side AT is shown to be somewhat less than the wall-side AT for the fIXed thennocouple
measurements where the opposite is seen from the thennopile The worst discrepancy is
on the order of 10 and is probably due to the fact that the thennopile gives an average temperature difference at several vertical locations on the wall whereas the other method is
at one vertical location only
Since the thennopile produces an average temperature difference across the steel skin its
output is used to detennine the heat flux into the cabinet The refrigerator casing is being
used as a heat meter Thus the flux along the skin in the fresh food compartment on the
wall-side is
kmiddot ATwallffqwallff = m (44)
Ax
The load qwallJf is Eq (44) multiplied by the cross sectional area This area is the
thickness of the steel casing multiplied by the perimeter that is exposed to the room
ambient This perimeter varies for each of the two paths that comprise qwall and the two
paths that comprise qdoor The other cabinet loads are computed in a similar way and are
given in Table 42 The details of these values are given in Appendix E
Table 42 Experimental Determination of qwall and qdoor
Section Load W (BtuIhr)
qwallJf 28 (96)
qwallJz 21 (72)
qwall 49 (168)
qdoorff 33 (112)
qdoorJz 33
1112)
qdoor 66 (224)
20
45 Experimental Determination of qmulloff
The region that lies between the fresh food compartment and the freezer is called the
mullion The front portion of the mullion is covered by a thin steel face plate to provide a
suitable interface for the door seal magnets In this section the load due to heat conduction
along the mullion steel skin into the freezer and fresh food compartment is detennined
based on the experimental data
The heat transfer rate qmulloff is sum of two parts The first component is the heat
conduction along the steel plate into the fresh food compartment and the second is the
conduction into the freezer
qmulloff = qmulloffff + qmullofffz (45)
Figure 49 schematically illustrates paths of these two components
FREEZER
FRESH FOOD COMPARTMENT
Fig 49 Heat Flow Paths in Mullion
21
Ten 36 A WG type T thennocouples are mounted from top to bottom across the steel face
plate Figure 410 shows the cross section of the plate and the location and numbering of
the thennocouples
FREEZER
1bennocouplesSteel Face (5 mm spacing from
Plate bottom edge)
Freezer Gasket
Fresh Food Gasket
10 50
FRESH FOOD COMPARTMENT
1 in =254 mm
Fig 410 Mullion Face Plate Cross Section
Data are gathered from the ten thennocouples when the unit is shut off and allowed to drift
to a quasi-steady ambient temperature A total of five runs were perfonned Figure 411 is
a sample plot of the quasi-steady temperature profile All other plots are contained in
AppendixE
22
116
Run 1 I 115 ICcIIIII114 iii t ~mull~ =12~7 - 00~654xa
~ 113
rrfIIJ~~If112i 5 )mullfz 1= 1081~ + OOdl25X 111111 ~
11 oo+-t--t-iH-+-lo-shyiii i i Room Ambient = 2184 degc
109 middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1middot Fresh Ambient = 381 OC
108
1 10
I I I I I Freezer Ambient =-832 degc
2 3 4 5 6 7 8 9
TIC
Fig 411 Mullion Temperature Profile
The plot also shows two linear equations These represent linear fits to each side of the
peak temperature at TIC 7 The slopes (shown in degCmm) are used to detennine the heat
conduction to each compartment by eqs (46) and (47)
lmulloffff = km A (aT) (46)ax offff
qmul)offfz = km AIll) (47)ax offfz
The cross sectional area is the product of the face plate thickness (10 mm 0039 in) and
the length of the mullion (717 mm 2825 in) The average slopes from all five runs are
used to detennine qmulloffff and qroullofffz The results are given in Table 43
23
Table 43 Experimental Results from Mullion Analysis
Load W (Btuhr)
09qmullofUz (31)
07qmulloffff (24)
16qmuIlorr (55)
46 Experimental Determination of qmullon
In this section the load due to heat conduction along the mullion steel skin into the freezer
and fresh food compartment when an anti-sweat heater is on is experimentally determined
The test unit is equipped with an electric anti-sweat heater to eliminate condensation in the
mullion region The heater is installed on the back side of the plate and may be switched on
manually when needed It is a wire resistor type rated at 10 watts
The heat transfer rate qmullon is composed of two parts The first component is the heat
conduction along the steel plate into the fresh food compartment and the second is the
conduction into the freezer similar to ~ul1off
qmuIlon = ~ullonff + qmuIlonfz (48)
The location of the wire heater and the heat transfer paths are shown in Figure 412
24
FREEZER
qmullonfz
qmullonff
FRESH FOOD COMPARTMENT
Fig 412 Electric Heater Location
A series of tests are perfonned while the heater is on and the refrigerator is cycling
nonnally Three runs are done at each of three separate locations along the mullion
laterally (i) LEFT dermed as 180 mm (71 in) from the left-hand side of the unit (ii)
RIGHT 180 mm (71 in) from the right-hand side of the unit (iii) CENTER at center of
the mullion Figure 413 is a plot of the temperature profile across the face plate when the
heater is on for a specific test run The plots for all other runs are provided in Appendix E
The plot shows two profiles These represent the upper and lower limits as the unit cycles
The upper limit occurs just before the compressor turns on while the lower limit is at the
point in time just before the compressor shuts off At all times in between the profile
oscillates between the two limits maintaining nearly the same shape Once again a linear
fit is applied to the data on the fresh food side and the freezer side
25
30 iii imiddot iii i
29
28
27
Run 1
T mu
ill~~ 11 f = 26707 + 010776x Tmu11ff = 3128 - 00793x
Z +_ a 26~
I ~
middotmiddotmiddotbull-middotbullimiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotimiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotimiddotmiddotmiddotimiddotmiddot
24
25
e 23~ =H-T+H~i=i=
iimiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotimiddotmiddot T 11 ff = 27435 - 009504x 22 Tmullfz =21865 + 01l786x I m~ iii
21 -lmiddotmiddotmiddotmiddotmiddotmiddotmiddot-tmiddot Upper Limlt 0
20 middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotjmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotimiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddott 0 Lower Limit
19
0 1 2 3 4 5 6 7 8 9 10
TIC I
Fig 413 Mullion Temperature Profile With Heater On (Center)
Heat fluxes are computed identically to the method in Section 45 using the average slopes
from all nine runs The minimum value occurs just before to compressor turns on while
the maximum value occurs just before the compressor shuts off during normal cycling
The load is averaged over the cycle time which is approximately 50 for the test unit and
laboratory conditions The results are given in Table 44
Table 44 Experimental Results from Heater Analysis
Lower Profile Average W
(BtuIhr)
Upper Profile Average W
ffituhr)
qmullonfz 73
(249) 53
(181)
qmullonff 23 (78)
26 (89)
96 (32 7)
79 (270)
qmullon 88
300)
26
47 Determination of Qmisc
The load qoisc is comprised of three main parts The first is the load due to the evaporator
fan motor The fan that moves cool air in the cabinet also adds a thennalload Fans of this
type in use range from 8 - 16 watts The fan of our test unit is rated at 92 watts This
value must be integrated over the cycle time The cycle time for the unit is approximately
50 for the test conditions Thus the value of qfanave is 46 watts
The load qdefrostave is not determined experimentally Instead an estimate is obtained from
a similar study done by Turiel and Heydari (1988) This value is 5 watts which is an
average of the defrost heater input over the defrost cycle The defrost cycle can range from
10 - 12 hours of compressor run-time
The fmalload qcompave is detennined by measuring the cabinet surface temperature at the
region surrounding the compressor and computing the heat transfer locally The value is
found to be 2 watts Table 45 summarizes the results
Table 45 Miscellaneous Loads
Load W CBtuhr)
46 qfanave (15middotU
50 qdefrostave _07Ql
20 qcompave (68)
116 Qmisc (395)
27
s NUMERICAL SIMULATION
In this chapter a two-dimensional numerical model which is used to simulate the steadyshy
state heat transfer in the wall near the door seal is discussed The results from the model
include a computation of qwallff qwallfz and the complete temperature distribution across
the section The model is also used to estimate the additional cabinet load due to the
presence of an anti-sweat condenser tube embedded beneath the outer casing that runs
along the perimeter of the unit A separate model is presented which is used to simulate the
two-dimensional heat transfer across the door seal cross section The results are used to
determine qseal
51 Wall Model
A finite-difference technique is used to approximate the steady-state temperature
distribution in the wall section The technique is applied to solve the governing steady
two-dimensional heat conduction equation (assuming constant conductivity with no
generation)
(51)
Equation (52) is the basic fmite-difference representation of the conduction equation in a
homogeneous medium of constant conductivity with no heat generation (White 1988) In
Appendix F a complete list of all the model difference equations is provided
2(1+(3)Tij = (3Tij+l + Ti+lj+(3Tij-l + (3Ti-lj (52)
where (3 = (llxlly)2
28
Figure 51 is a sketch of the model representation of the refrigerator wall at the door seal region The dimensions shown are flexible parameters in the model The model allows for
slight changes in the geometry as well as changes in mesh size in both x and y directions
However the mesh size must remain uniform across the section
s5 s6
sl
Fig 51 Wall Heat Conduction Model Sketch
For each of N unknown nodal temperatures N simultaneous linear algebraic equations are obtained for N unknowns If N is large as is the case for this simulation an iterative
technique is preferred to solve the system ofequations A Fortran program has been
written to carry out the finite-difference iteration A copy of the code is given in Appendix
F A simple Guass-Seidel technique is employed for the differencing iteration At each
iteration an energy balance is done for the entire section In theory this balance should be
29
zero (heat entering) = (heat leaving) The iteration is continued until the difference
between heat entering and heat leaving is equal to 1 of the total heat entering the section
Table 51 defines the input parameters for the simulation
Table 51 Wall Simulation Input
Code Parameter Definition
To C (F) Exterior surrounding ambient temperature
Ti C (F) Interior ambient temperature
lan Wm-K (Btuhr-ft-F) Steel skin conductivity
kp Wm-K (Btuhr-ft-F) Plastic skin conductivity
kins Wm-K (Btuhr-ft-F) Wall insulation conductivity
heffo Wm2-K (Btuhr-ft2-F) Outside effective heat transfer coefficient
hefti Wm2-K (Btuhr-ft2-F) Inside effective heat transfer coefficient
dm mm (in) Steel skin thickness
dp mm (in) Plastic skin thickness
dx mm (in) Mesh size x direction
dy mm (in) Meshsizeydirection
sl mm (in) Wall width
s2 mm (in) Wall length
b mm (in) Effective Perimeter
s3 mm (in) Seal indentation
s4 mm (in) Seal width
s5 mm (in) Depth of steel skin into cabinet along seal boundary
s6 mm (in) Width of plastic skin along seal boundary
The model assumes that the boundary that lies along the door seal is adiabatic This allows
the separation of the wall section from the rest of the geometry in this region The seal and
door can then be treated separately later A simple calculation is done to validate this
assumption
30
Steel Skin (Refrigerator wall)
Seal (k = 02 Wm-K)
Fig 52 Non-adiabatic Door Seal
A 2 degC temperature difference AT is imposed across the seal This is a slight overshy
estimate based on the experimental data An estimate of the conductive heat flux is
determined from Eq (53)
ATqerror=k- (53) Ax
qrror =02 Wm-C o~Cm =20 Wm2
The heat flux ql for the fresh food compartment is determined in Appendix E to be 14418
Wm2 Therefore qerror represents approximately 13 of the total flux Hence this
term is neglected in this study
Two other possible sources of error are associated with the fmite-difference technique itself
(Ozisik 1980) The fIrSt is called truncation error and arises from the discretization of the
second-order derivative in the steady conduction equation The second is referred to as the
round-offerror which is due to the fact that numerical calculations are carried out only to a
finite number of decimal places Repeated solution with smaller increments shows that the
truncation error is negligible The precision of the energy balance is evidence that the
round-off errors are negligible
31
S2 Wall Simulation to Determine qwall
The finite-difference model is used to detennine the wall-side heat transfer along the steel
skin However more valuable information is yielded from the simulation The nodal
temperature distribution is detennined which gives insight into the direction and magnitude
of heat fluxes throughout the section The fresh food compartment and the freezer are both
simulated to detennine qwallff and qwallJz respectively Table 52 is the list of the values
used for the model input parameters for both cases
Table S2
Code Parameter
To C eF)
Ti C eF)
kIn Wm-K (Btuhr-ft-F)
kp Wm-K (Btuhr-ft-F)
kins Wm-K (Btulhr-ft-F)
heffo Wm2-K (Btuhr-ft2_F)
heffi Wm2-K (Btuhr-ft2-F)
dm mm (in)
dp mm (in)
dx mm (in)
dy mm (in)
sl mm (in)
s2 mm (in)
b mm (in)
s3 mm (in)
s4 mm (in)
s5 mm (in)
s6 mm (in)
Input Values
Fresh Food 210 (698) 40
(392) 540 (312) 015 (009) 0027 0015t 687 (121) 670 (118) 065
(0026) 25
(0098) 225
(0088) 25
(0098) 450
(1772) 2000 (7874) 2960
(11653) 225
(0088) 2025 (0797) 225
(0886) 2025 (0797)
32
Freezer 210 (698) -10
(140) 540middot (312) 015 (009) 0027 (0015) 687 (121) 641 (113) 065
(0026) 25
(0098) 28
(0088) 25
Jo098) 540
(2125) 2000 (7874) 1580
(6220) 28
(0110) 196
JO772) 224
(088t) 288
(1134)
The output from the simulation includes the entire nodal temperature field heat fluxes at
each node along the centerline heat fluxes from node to node along the steel skin beneath
the door seal and the value for qwallff and qwallcz These heat transfer values and the
nodal temperature distribution are listed in Appendix F
The quantities qwallff and qwallcz are determined by computing the heat fluxes from node to node along the centerline of the section subtracting the one-dimensional flux and then
multiplying by the cross sectional area for that node and summing to give the total heat
transfer rate The primary results are shown in Table 53
Table 53 Wall Simulation Results
Section
The temperature distributions are shown in the following two figures Figure 53 shows
the temperature contour for the fresh food results Figure 54 is the same plot for the
freezer results
Since the geometry of the refrigerator door is similar to that of the wall along the edges the
heat leakage to the food compartments along the door flange can be approximated as being
roughly the same as qwall This approximation of qdoor is a good means of estimating the
two prime contributors to the edge loss for various different refrigerators which may have
slightly different geometries as well as different material properties
33
i
3875
3625
TemplaquogtC)
-e
11111
20
18
16 3375
g 3125 14 -5 2875 ~ 122625 ~
2375~ 102125~
1875 8
1625
1375 6
1125
875 4
625
375
SteeVPlastic Liner Interface
Fig 53 Fresh Food Wall Temperature Distribution
34
i 4875
4625
4375
4125
3875
3625
3375 -
3125e g 2875
2625 ~ 2375 ~ 2125c (I)
1875 ~ 1625
1375
1125
875
625
375
125
Fig 54 Freezer Wall Temperature Distribution
Temp(OC)
20
15
10
5
0
-5
-10
35
53 Wall Edge Simulation to Determine qtube
The wall simulation is modified to include a constant temperature node placed beneath the
steel flange to represent the presence of an anti-sweat condenser tube The simulation is
perfonned for the specific conditions that are typical of the test unit as well as a range of
lateral tube locations For the test refrigerator the tube is located as shown in Figure 55
and is at 35degC (95 OJlt)
Outer Steel Skin
14625 mm 1
Inner Plastic Liner
Fig 55 Tube Location for Simulation
The quantity qtube is detennined by taking the fluxes along the vertical line to the left of
the tube subtracting the one-dimensional flux and then multiplying by the cross sectional
area for that node and summing to give the total heat transfer rate Again the fresh food
compartment and the freezer must be simulated separately to produce a total governed by
Eq (54)
(54)
Program output for the fresh food and freezer simulations is given in Appendix F Table
54 summarizes the results from the model
Table 54 Wall With Condenser Tube Simulation Results
Section Load W iBtubrl
qtubeff 46
(157)
qtubefz 28 (96)
qtube 74 (253)
qtube8ve (ave for 50 cycle time)
37 (126)
36
-I i c IJ
~
r 4875
4625
4375
4125
3875
3625
3375
3125
2875
2625
2375
2125
1875
1625
1375
1125
875
625
375
125
TempfC)
SteeVPlastic Liner Interface
35
30
25
20
15
10
5
Fig 56 Fresh Food Wall Temperature Distribution Including Warm Anti-sweat Tube
37
TempfC)4875
4625
4375
4125
3875
3625
3375 - 31258
2875g 2625fo 2375
3 2125 d vI 1875
~ 1625
1375
1125
875
625
375
125
SteeVPlastic Liner Interface
Fig 57 Freezer Wall Temperature Distribution Including Warm Anti-sweat Tube
38
40
30
20
10
0
-10
The heat fluxes at each node along the vertical line to the left of the tube are also computed
by the simulation This value quantifies the amount of heat that is moving toward the outer
boundary and is used to determine the percentage of heat entering the cabinet For the test
refrigerator this value is 18 for the fresh food compartment and 24 for the freezer
Several more simulation runs were done to find the effect of lateral placement of the tube on
the overall heat transfer and the percentage of heat entering Figure 58 and Figure 59
show the trends that are found
-~ a tUbe ~middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotlmiddotmiddotmiddot=middotmiddot=pmiddotmiddotmiddot=middot-1- =1
middot middot middoti middot middotmiddotmiddotmiddotmiddotmiddotmiddotmiddot bull middotmiddotmiddot i middotmiddotmiddotmiddot middotmiddot middotmiddot ~ middotmiddot
middotmiddotrmiddot-rmiddot 0 lwbeff middotlmiddotmiddot~middot Gmiddottmiddotmiddot9middotlmiddot
i i -0- lwbe i middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotimiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddot fz tmiddotEimiddotmiddot ~G- -~ -q- -
0 5 10 15 20 25 x(mm)
Fig 58 Load Due to Condenser Tube for Various Tube Placements
8
~ - 7
50
a 6
~ 5
~ en 4 ~
pound ~ 3
2
- 26
~ a 24
middots bO
pound 22c ~
~ 20
a = 18sect ~
16 0 5 10 15 20 25
x (mm)
Fig 59 Percentage of Heat Entering Cabinet for Various Tube Placements
39
54 Door Seal Simulation to Determine qseal
Another model is developed for the two-dimensional heat transfer through the door seal
This model is very similar to the one created for the wall section Once again a fIniteshy
difference technique is utilized to detennine the temperature distribution at steady-state
conditions Even though the cross sectional geometry of the seal is simplifIed to a square
with a hollow square with a centrally located cavity no closed-form solution can be
applied Therefore a simulation is needed
The fInite-difference representation of the two-dimensional steady Eq (55) using central
differencing is given by Ozisik (1980)
Ti-lj - 2Tij + Ti+lj + Tij-l - 2Tij + Tij+l = 0 (55) Ax2 Ay2
For this model a square mesh is applied reducing Eq (55) to
Ti-lj + Ti+lj + Tij-l + Tij+l - 4Tij = 0 (56)
x
Fig S10 Seal Simulation Mesh Layout
40
The nodes along the vertical surfaces at x=O and x=20 are subject to the convective
boundary conditions and governed by Eq (57) and Eq (58) respectively
2~xheffol 2~heffo2Ti+lj + Tij-l + Tij+l - (4 + k TiJ = - k To (57)
seal seal
2~heffffl 2~heffff2Ti-lj + Tij-l + TiJ+l - (4 + kseal Tij = - kseal Tff (58)
The nodes along the top and bottom outside surfaces are held at the prescribed temperature
profIles which are detennined from experimental data (see Section 41) The interior nodes
are subject to radiant e~change among themselves and conduction through what is assumed
to be stagnant air A closer look at the model of the hollow interior of the seal is shown in
Figure 511
Fig 511 Seal Cavity Mesh Details
Each interior node corresponds to a single gray surface with assumed emissivity of 09
Viewfactors for all surfaces are computed automatically before the iteration begins For
each iteration the effect of radiation within the enclosure is taken into account by updating
surface radiosities Jij Thus for nodes on interior surfaces an extra tenn is added to the
governing difference equation (Eb is the blackbody radiation)
41
~(J - Eb )1-pound IJ lj
A code written in Fortran is used to perfonn Guass-Seidel iteration of the difference
equations to compute the temperature distribution at mesh nodes (Code listing in Appendix
F) Once again convergence is based on an energy balance applied to the entire section
The iteration is continued until the difference between heat entering and heat leaving is
equal to 01 of the total heat entering the section Table 55 lists the input parameters
used in the model The fresh food compartment and the freezer compartment are simulated
separately
Table 55 Seal Simulation Input
Code Parameter Fresh Food Freezer
Number of nodes along outside edge 20 20
Number of nodes along inside edge 6 6 1 1Lx = fly mm (in) (0039) (0039)
210 210Outdoor ambient temperature degC (oF) (698) (698) 150 105Indoor local ambient temperature degC COF) 590J j509)
Outdoor heat transfer coefficient W m2-K 687 687 (121) (121)(Btuhr-ft2-F)
Indoor heat transfer coefficient Wm2-K 670 641 (118) (113)(Btuhr-ft2-F)
Gasket interior surface emissivity 09 09 03 03Gasket conductivity Wm-K (Btuhr-ft-F) (0173) (0173)
Wall-side Temperature Boundary 1905 - 1977x 1813 - 3475x Condition degC Door-side Temperature Boundary 1913 - 1384x 1852 - 2341x Condition degC
42
The load results are summarized in Table 56 below The program output is listed in
AppendixF
Table 56 Seal Simulation Results
Load W Section (BtuIhr)
10 Qsealff (34)
ljQsealfz (Sn
25qseal (85)
The steady-state temperature distribution is shown in the figures below Figure 512 is the
fresh food simulation and Figure 512 is the freezer simulation The direction of the heat
flow through the section is easily seen from these plots
43
Wall-side Boundary Temperature (C)
~~
I 20
195
i 19t 0
8 ~ 1859 -- ~
isis ~ ampJ gtshy 18 ~
11 ~ S ~ 175~
~ 17
165
x(mm)
Door-side Boundary
Fig 512 Seal Temperature Distribution (Fresh Food)
44
Wall-side Boundary Temperature (C)
Ii 19
185
18i f IQ 5 IQ
175-is-is I s 17j ~
5e 0C= 165
~ ~ 16
155
x(mm)
Door-side Boundary
Fig 513 Seal Temperature Distribution (Freezer)
45
6 DISCUSSION OF RESULTS
The heat transfer values detennined from the experimental analysis and the numerical
simulations are the various components that embody the cabinet load on the refrigerator It
is important to separate cabinet loads from system loads The system load can be thought
of as the total electrical energy consumption of the unit It has four basic components (i)
the compressor (ii) fans (iii) anti-sweat heaters and (iv) defrost heaters The first two
components the compressor and fans are the cost of removing heat from the cabinet This
amount of heat is equal to the cabinet load divided by the COP of the system The typical
energy consumption is shown schematically in Figure 61
System Load (Energy Consumption)
Defrost Heater (averaged over time
cycles every 10-12 hours of compressorrurt-time)
TuneCycle
Fig 61 Refrigerator System Load Graph
In a study done by Turiel and Heydari (1988) the compressor and fans accounted for 84
of the total system load for an 180 cubic foot top-mounted refrigerator Staley (1992)
found this value to be 86 for a similar unit Both of these studies used system analysis to
determine these numbers The energy consumption of the components were monitored
during operation The energy consumption of our test refrigerator can be determined in a
reverse manner from the cabinet load data If a COP of 1 is assumed the test refrigerator
46
compressor and fans accounts for 86 of the energy consumption to cool the cabinet This
compares favorably with the fmdings of Turiel and Heydari (1988) and Staley (1992)
Figure 62 is a schematic of the cabinet loads One possible load that is not included in the
figure is the heat input associated with the defrost drain tube that runs through the back
wall However this term is probably small relative to the other contributors
Cabinet Load
qseal qdoor
qwall
qmullon
qdefrostave
Fig 62 Cabinet Loads Graph
All the loads are determined in this study from either experimental measurements
numerical simulations or both Most of the loads are quasi-steady that is they do not
fluctuate significantly over the cycle time of the refrigerator There are four loads shown in
Figure 61 that are cyclical in nature The three loads that appear only while the
compressor is running are qcomp qfarb and qtube Also the refrigerator is subjected to a
load every time ice build-up is removed by the defrost heaters This load is averaged over
its own cycle time and shown in the graph as qdefrostave
47
61 Comparison of Simulation Results with Experimental nata
The majority of the cabinet loads are detennined from experimental data with the exception
of qseal and qtube The wall and door flange loads aremiddot also found from the numerical
simulation (see Chapter 5) The two-dimensional model detennines the wall-side heat
transfer along the steel skin into the food compartments No model is available to directly
detennine the heat transfer on the door-side However since the flange geometry on the
door-side is similar to the wall the value for qwall is considered to be a good estimate for
qdoor Table 61 gives these values determined from experimental measurements and the
simulation
Table 61 Comparison of Simulation and Experimental Values for qwall and qdoor
Experimental Result W Simulation Result W (BtuIhr) (BtuIhr)
qwallff 28 (96)
28 (96)
qwallz 21 (72)
27 (92)
qwall 49 (168)
55 (188)
ldoorff 33
(112) 28 (96)
qdoorfz 33
(112) 27 (92)
qdoor 66 (224)
55 (188)
The model predicts qwall to within 57 of the experimental value The agreement of the
estimate of qdoor with the experimental value is within 90
Some of the shortcomings in the model used in this investigation are
(i) Only the wall is modeled Ideally the entire region should be considered including the
door and seal (see Figure 11)
(ii) The flange geometry is simplified The steel casing skin in the flange region may bend
in more complex ways Also the plastic liner varies in thickness near the door seal
(iii) The mesh must be unifonn There is no means to vary how fme the mesh can be The
ideal situation would be to have a fine mesh near the edges and a course mesh far from the
seal
48
62 Mullion Analysis
The single largest edg~ load is found in the mullion section (329 of qedge and 94 of
qtol) This load is due to the electric anti-sweat heater installed on the backside of the face
plate The heater is rated at 10 watts and approximately 88 of that input enters the
interior of the cabinet as a thennalload This is probably due to the small surface area
exposed to the room and the low amount of convective heat transfer in the channel between
the fresh food and freezer doors With the heater on 88 watts is measured enter the food
chambers With the heater off only 16 watts enters the interior The addition of the
heater increases the mullion load 55 times Generally it is not necessary to use the
mullion heater at all times However for the test environment the heater nearly all the time
to eliminate sweating under the laboratory conditions
63 Seal Analysis
The heat conduction directly through the seal accounts for the smallest portion of the edge
loss (94 ofqedge and 27 of qtol) The numerical model to detennine these values uses
a simplified representation of the complex cross sectional geometry of an actual door seal
The various air pockets are reduced to a single hollow void There is no experimental data
to verify the model However the numbers and trends resulting from the simulation are
reasonable
64 Anti-sweat Condenser Tube Analysis
Thennocouple drag tests were perfonned to give insight into the nature of the temperature
profIles at the wall steel flange with the presence of an anti-sweat condenser tube The wall
heat transfer simulation model was modified to include the effect of this tube The heat
conduction to the interior increased by 76 at the wall flange region The amount of
additional loading due to the tube depends on several parameters location of the tube
temperature of the circulating refrigerant and local wall geometry Although the model is
flexible enough to handle vari01~S temperatures and limited geometrical changes only the
influence of tube position was investigated As the tube is moved towards the interior the
load increases For the test refrigerator about 20 of the heat flow was directed to the
interior compartments primarily along the steel skin
49
6S Overall Cabinet Load
The overall cabinet load is defined as a sum of three parts
(61)
The edge load is
qedge = qwall + qdoor + Qseal + Qrnullon + qtubeave (62)
where
qwall
qtubeave
heat input due to the conduction along the wall steel flange
heat input due to the conduction along the door steel flange
heat conduction directly through the door seal
heat input due to conduction in the mullion region with the additional input from anti-sweat heater
heat input due to cabinet anti-sweat condenser tube averaged over the cycle time
heat input due to cabinet anti-sweat condenser tube
qmulloff heat input due to conduction in the mullion region electric heater off
The terms of Qrnisc are defined as
qmisc = qfanave + qdefrostave + qcompave (63)
where
qfanave heat input from the evaporator fan averaged over the cycle time
qdefrostave heat input from the defrost heaters averaged over defrost cycle time
qcompave heat input from elevated exterior walls near the running compressor
Table 62 presents the overall cabinet load analysis results
50
Table 62 Overall Cabinet Loads
Load W Load Btuhr Total
qlD 550 1876 591
qedge 265 903 285
Qwall 49155 167 188 53
Qdoor 66155 2251 188 71
Qseal 25 85 27
Qmullon 88 300 94
Qtubl ngt 37 126 40
qmisc 116 395 124
Qfanave 46 157 49
Qdefrost ave 50 170 54
qcomoave 20 68 21
qtot 931 3174 100
Simulation Results
All loads are detennined experimentally with the exception oflsea1 and qtubeave The
values for qwall and qdoor are detennined from both experimental data and numerical
simulations Edge loss per unit length along fresh food perimeter is 29 Wm (30 Btuhrshy
ft) the loss per unit length along the freezer perimeter is 44 Wm (46 Btuhr-ft) and the
loss along the mullion section is 123 Wm (128 Btuhr-ft) with the heater on and 22 Wm
(23 Btuhr-ft) with anti-sweat heater off
The largest single load is the one-dimensional conduction through the walls and doors
The edge load comprises 285 of the total a significant portion The largest edge load is
due to the electric anti-sweat heater that is installed in the mullion section The smallest
edge load is due to the heat conduction through the fresh food and freezer door seals The
losses at the wall-side and door-side flange regions account for 53 and 71 of the total
load respectively These could be considered together since the pathway of heat transfer is
very similar If that were the case the sum of qwall and qdoor would be the second largest
contributor to the overall cabinet load The influence of an anti-sweat condenser tube is
reflected in the value of qtubeave Although this additional load is larger than qwall it must
be integrated over the refrigeration cycle timewhich is 50 of the cycle time for the test
unit The tube boosts the heat transfer along the wall flange by 76
51
To round out the cabinet load three miscellaneous loads are considered The evaporator
fan motor produces a heat load within the cabinet which is considered to be equal to the
power rating of the fan The automatic defrost feature is another thermal load that is
cyclical appearing about every ten to twelve hours of compressor runtime The fmalload
is due to the elevated exterior skin temperature near the compressor when it is running All
three of these loads are averaged over their cycle times for comparison with other quasishy
steady loads As a total qmisc represents 124 of the overall cabinet load
Opportunities to decrease the one-dimensionalload are available The emphasis has been to
develop super-insulations to be installed in the refrigerators Some being considered are
vacuum panels aerogels and vacuum packed powder insulations The disadvantages of
this improvement lies within the need to develop a cost-effective technique for fabricating
and installing such technologies compatible with high-volume manufacturing Also edge
losses and panel connection losses must be minimized due to the difficulty in making a
panel the size of refrigerator interiors Reliability of the seal and perfonnance of the outer
envelope need to be ensured over a long period of time ie the expected life of the
product
The possibilities of reducing the loads along the edge of the refrigerator aperture are
somewhat less apparent One method of reducing quasi-steady heat conduction along wall
and door flanges is to raise the inside cabinet wall temperature by minimizing interior film
surface heat transfer coefficients This could be accomplished by the use of low-emissivity
surfaces on the interior walls or on sections nearest the edges The need for an anti-sweat
device for the perimeter is also eliminated supplying a two-fold savings by reducing the
cabinet ioad and the system energy consumption The need for an electric mullion heater
might also be done away with by the same means The drawback again would be to make
such modifications acceptable and cost-effective for manufacture
The remaining miscellaneous loads provide some chance for improvement If the
efficiency of the fans is increased the energy use of the refrigerator can be reduced The
option of moving the fan motor outside the cabinet leads to other problems The motor
shaft must pierce the wall providing another path for heat leakage Also frost built-up on
the shaft would be a costly and difficult problem to eliminate If the compressor and
condenser were located near the top of the refrigerator they can operate more efficiently
Heat can be more readily convected away eliminating the need for the condenser fan
(Turiel and Heydari 1988) Frost fonnation in the freezer varies significantly depending
52
on the ambient conditions and the freezer usage The defrost cycle could be made more
energy efficient with the addition of adaptive controls All of these improvements would
require redesign of the product and the manufacturing process This is a very expensive
alternative which would need to be justified by the associated energy savings
53
7 SUMMARY OF CONCLUSIONS
The following is a list of the important findings produced from this study
(i) The edge loading accounts for a significant portion of the total cabinet load For the
test unit used in this study an 18 cubic foot top-mount refrigerator this load was
approximately 30 of the total load The load includes losses along the wall and door
flanges conduction through the door seal mullion loading with an electric anti-sweat
heater on and additional thennal input from an anti-sweat perimeter condenser tube
(ii) The presence of an electric anti-sweat mullion heater boosts the mullion loading by
a factor of approximately 5
(iii) The presence of an anti-sweat condenser tube around the perimeter of the refrigerator
increases the wall flange load by approximately 75
(iv) The presence of the door air damt reduces the temperature difference across the door
seal to 35 of the temperature difference between the interior and exterior
environments
(v) The hypothetical elimination of the additional load due to the electric anti-sweat
mullion heater reduces the edge loading to approximately 22 of the total cabinet
load
(vi) The hypothetical elimination of the load due to the anti-sweat condenser tube reduces
the edge loading to approximately 25 of the total cabinet load Ifboth anti-sweat
devices were not needed the edge loading would be further reduced to only 17 of
the total
(vii) During the course of this investigation it was concluded that the experimental and
numerical methods developed are applicable to most refrigeratorfreezers that are
produced today
t The portion of the door liner that extends into the cabinet along the wall
54
REFERENCES
Braswell A 1988 Impact of CFC Regulations on the Air Conditioning and Refrigeration Industry International Jow-nal ofRefrigeration Vol 11 No6 p 385
Cabot Corporation 1987 CAB-O-SIL Fumed Silica Properties and Functions Tuscola n pp 12-15
Clausing A M 1983 Natural Convection Correlations for Vertical Surfaces Including Influences of Variable Properties ASME Jow-nal ofHeat Transfer Vol 105 No 1 pp 138-143
Incropera FP and Dewitt DP 1985 Fundamentals ofHeat and Mass Transfer Second Edition John Wiley and Sons New York
Ingersoll LR Zobel OJ and Ingersoll AC 1954 Heat Conduction with Engineering and Geological Applications McGraw-Hill Book Company New York
Little AD Inc 1982 Refrigerator and Freezer Computer Model Users Guide Cambridge Massachusettes
Micropore International Ltd Microtherm Thermal Insulation Worcestershire England Section 1
Nix GH Lowery GW Vachon RI and Tanger GE 1967 Direct Determination of Thermal Diffusivity and Conductivity with a Refined Line-Source Technique Progress in Astronautics and Aeronautics (Vol 20) Thermophysics ofSpacecraft an Planetary Bodies Academic Press New York pp 865-878
Nix GH Vachon RI Lowery GW and McCurry TA 1968 The Line-Source Method Procedure and Iterative Scheme for Combined Determination of Conductivity and Diffusivity Thermal Conductivity Proceeding of8th Conference
Ozisik MN 1980 Heat Conduction Wiley-Interscience Publishing New York pp 486-487
Staley D 1992 Personal Communication Graduate Research Assistant University of Illinois Urbana
Turiel I Heydari A 1988 Analysis of Design Options to Improve the Efficiency of Refrigerator-Freezers and Freezers ASH RAE Transactions Vol 94 Part 2
Van der Held EFM and Van Drunen FG 1949 Physika Vol 15 No 10 p 865
White PM 1988 Heat and Mass TranSer Addison-Wesley Publishing Reading Mass pp 145-160
55
APPENDIX A FUMED SILICA INVESTIGATION
A ~ 1 Introduction
Fumed silica is a micro-porous powder comprised of submicron particles of amorphous
silica bonded together in a cellular structure Several grades of silica are available offering
a selection ofdifferent grain sizes and chemical treatments Fumed silica is commonly used
to provide thickening thixotropy suspension and other related properties in liquid
systems In dry systems it is used to promote free flow frictionizing and anti-blocking
properties Thus it is a versatile additive in materials such as inks coatings adhesives~
and silicon rubber (Cabot Corporation 1987)
The thermal insulating properties of this material have been somewhat less widely applied
however fumed silica as an insulation displays some interesting properties Fumed silica
insulations are commercially available and have become a more popular material for certain
specific applications In this section the results of an investigation of the thermal
properties of one type of fumed silica is presented
A2 Thermal Properties
As an insulator fumed silica uses the microporous principle to reduce thermal conduction
to the theoretically lowest possible levels (Micropore International Ltd 1988) Most
conventional insulations rely upon voids normally occupied bj alt aS the meanS ot
minimizing heat transfer through the material Therefore it is important to maintain these
voids for maximum insulation Fumed silica is comprised of tiny spheres with diameters
of the same order of magnitude as the mean free path of the molecules in the air
Therefore when these spheres are packed closely together gaseous conduction and
convection are minimized The cell size is sufficiently small to keep convective currents
from forming and to trap gas molecules to rebound elastically thereby not imparting their
energy to slower moving molecules In addition solid conduction is minimized by the fact
that silica is a material with intrinsically low thermal conductivity These unique properties
make fumed silica an attraCtive alternative to conventional insulations
56
A3 Experimental Method
Thennal conductivity and thennal diffusivity are the properties detennined from our
experimental study Many methods exist for establishing the thennal properties of a given
substance Both steady-state and transient procedures are available The hot-wire method
is a the transient procedure used in this study
The practical form of the hot-wire method is given by Van derHeldand Van Dronen
(1949) who used it to detennine conductivities of liquids Nix et al (1967) elaborated to
give a method for the simultaneous detennination of both thennal conductivity and thennal
diffusivity Therefore it is possible to detennine both conductivity and diffusivity by
passing a known amount ofcmrent through a heater wire embedded in the test material and
recording the temperature at a point on the wire and at a fixed point from the wire over the
period of the test From the temperature history of the point contiguous to the hot-wire the
conductivity can be detennined directly From the temperature history of the point at a
fixed distance from the hot-wire the diffusivity may be computed Both procedures are
outlined in the following section
A4 Theory
The temperature at any point in an infinite solid containing a line heat source of constantshy
rate is a function of the position time from initiation the thennal conductivity of the
material and the magnitude of the source This is shown mathematically by Ingersoll et aI
(1954) The cylindrical temperature field is expressed as
T=~l- exp-x2) dx (Al)21tk x
II
In series fonn
(A2)T=~[-amp-lnp+L-L+L_ ]21tk 2 21 4middot2 63
57
where
q = Heat input per unit length of wire [W1m]
k = Thennal conductivity of the material [Wm-K]
a = Thennal diffusivity of the material [m2s]
t = Elapsed time from heat liberation [s]
r = Radial distance from line-source [m]
Ce = Eulers constant (05772157 )
The temperature change between two times tl and t2 is accurate to better than one percent if
the value of ~ is less than 016 for a point very close to the line-source
(A3)
Equation (A3) is used in this case to detennine the thennal conductivity since the
diffusivity a and the radial distance T no longer appear in the relation Therefore
knowing the temperature at two different times during the test gives the conductivity
directly given that the value of ~ remains small This is achieved by choosing a point very
near if not contiguous to the hot-wire itself In our study a graphical method is used to
detennine the conductivity If the temperature versus the natural logarithm of the time is
plotted a straight line should be seen whose slope is equal to q4nk
Once the conductivity of the material is detennined the diffusivity can be found by the
method proposed by Nix et aI (1968) The temperature at a fixed and known distance
from the hot-wire must be monitored over the time period of the test Now since ~ gt 016
the diffusivity does not drop out of Equation (A2) Rewriting Equation (A3) as
(A4)
where
~2 ~4 ~6 ]r(~)= [ -~-ln~+---+-- (A5) 2 211 4middot2 6middot3
58
therefore (A6)
Using the temperature at the fixed location as an input Equation (A6) can be solved iteratively by means of Newton-Raphson technique to find the parameter ~ and thereby
yielding the thermal diffusivity a
AS Test Apparatus
Figure A1 is a sketch of the test apparatus used to collect thermal property data This
device provides a wide range of silica densities for packed tests Each half of the apparatus
is packed separately to the same density and then pressed together sandwiching the heater
wirethermocouple assembly between them
Remove bottom plate and press together with right half
Insert heater wirethermocouple assembl)
Remove bottom plate and press together with left half
Compact both halves to same density
Fig AI Fumed Silica Test Apparatus
Prior to loading the unpacked silica into the test cylinders the mass is carefully recorded
Each test cylinder has graduated marks to allow the volume of the sample to be computed
The density is then computed from the measured mass and volume At higher densities it
59
is sometimes necessary to load and compact several times Figure A2 is a schematic of the
heater wirethermocouple assembly and the entire test facility
Switch
Ammeter
Power Source
Cylindrical Test Section
Thermocouple for Conductivity
Data Acquisition System
Thermocouple for Diffusivity
Fig A2 Fumed Silica Test Facility Schematic
The heater wire used for all tests is 30 A WG nichrome wire with a nominal resistance of 2214 Wm Both thermocouples are type T 36 A WG Once the test sample is in place
the switch is closed allowing cUITent to pass through the heater wire The heat input per
unit length of the wire is determined from
(A7)
where q = Heat input per unit length of wire [Wm]
I = The input cUITent [Amps]
R = Heater wire resistance per unit length [Wm]
60
Knowing the heat input per unit length the temperature contiguous to the heater wire and
the temperature at a fixed distance from the heater wire over the duration of the test eqs
(A3) and (A6) can be solved This yields the conductivity and diffusivity respectively
A6 Results
All results presented in this section are from tests petfonned with a material sample donated
by Cabot Corporations Cab-O-Sil Division The silica is an untreated sample EH-5 with
a bulk density of 25 Ibsft3 and a nominal particle diameter of 70 angstroms Several tests
are petfonned at various densities The thermal conductivity is determined graphically as described above while the diffusivity is determined using a Fortran code to pe~orm the
Newton-Raphson iteration also outlined in Section A4
A total of seven different bulk densities are tested Each test consists of three runs at three
different power levels The temperature history is recorded for both thermocouples
Figure A3 is a plot of the temperature for the duration of a typical test for unpacked silica
70~--~----+----r----~-----~----+----r
10001
middot middot middot o 05 Ampsmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddot o 04 Ampsi ~ i
I i I I i oo~ct 60 IIJatr-T50
1 LL~40
1 ~ 1 010 1 ltgtom
JPi i30 i 0I1 o 03 Amps 1 I I
20~--~----+----r----~-----~----+----r
-10 o 10 20 30 40 50 60 70 Time (sec)
Fig A3 Time vs Temperature for Unpacked Run
61
To graphically detennine the thennal conductivity the temperatme data must be plotted
against the natural logarithm of time Figure A4 gives this plot along with the equations
that represent linear curve-fits to the straight portion of each curve
70~----~--------+------+--------~----~----~--------+-----~
60 ~ =l-LL-~--o T ~ 86839 ~ 1376 ~(t) I
50 ---f--H-deg--tfjtshy ~ T =11108 + 97346 m(t)
40 IT_oroJ~-
30 middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotImiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotsectmiddotmiddotmiddotmiddotmiddotImiddotmiddotmiddotmiddotmiddotmiddotmiddot~middotmiddotmiddotmiddot109~~Q9 T= 18431~ + 493 ~(t) 0
~ e i i i
20~----~--------+------+--------~---------~~----+------r
05 1 15 2 25 3 35 4 45 In (time)
Fig A4 Natural Log Time vs Temperature for Unpacked Run
All three curves should yield the same conductivity for the sample The conductivity is
detennined from the following relation
k= 12R (A8)4n(slope)
Table AI gives the average conductivity for each density level This is the average for the
three input cmrents used These results are also shown graphically in Figure A5
62
Table AI A verage Fumed Silica Conductivity for Various Bulk Densities
est
1
2
3
4
5
6
7
0024
0023
0022 -~ ct 0021
~ e 002
~
0019
0018
0017
i
~i
I I I I Imiddotmiddotmiddot_middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotimiddot_middotmiddot middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotimiddot-middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot
1i111
~ ~ iii
_I_1_1_1
I I I I I middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot middotmiddotmiddotmiddotmiddotmiddotmiddotfmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddot -r-t-o-rldegoo---shy
25 3 35 4 45 5 55
Density (lbsff)
Fig AS Conductivity vs Bulk Density
From the temperature data collected from the second thennocouple the thennal diffusivity
is computed (see Section A4) This thennocouple lies 3 mm (0118 in) from the heater
63
wire The output from the diffusivity iteration is provided in Table A2 A graphical
representation is given in Figure A6
Table A2 Average Fumed Silica Diffusivity for Various Bulk Densities
Test
Average Diffusivity m2s (ft2Jhr)
1 210 x 10-7 (000813)
2 166 x 10-7 (000643)
3 159 x 10-7 (000616)
4 155 x 10-7 (000600)
5 153 x 10-7 (000592)
6 No Data Available
7 151 x 10-7 (000585)
00085 -+----+-----f----+----+----+--_+_
I
middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1 ~0008
I I I I ~
I middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotfmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot Tmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot ~ 00075
~-shyf i ~ ~ ~ i ++middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotfmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot0007 i iii
~ rn ~ ~ i i~
(jj bullbullbullbullbullbull1bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullJLbullbullbullbullbullbullbullbullbullbullj ~ 00065o ~ middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot0006
I I I 00055 -+----+-----f----+----+----f--_+_
25 3 35 4 45 5 55
Density (lbsff)
Fig AS Diffusivity vs Bulk Density
64
A7 Conclusions
The primary conclusion from this experimental study is the fact that the thennal insulating
properties of fumed silica powder increase as the bulk density of the material increases
Although this study presents a limited range of density values the trends that were
expected are seen to be true The conductivity values are expected to reach and even
surpass those of CFC-blown foams that are used in household refrigerators Further
testing is needed to provide data that supports this expectation In addition testing in this
study was strictly limited to a single variety of silica This particular type of silica is not
necessarily the best candidate for thermal insulation applications Silica powders are by
nature hydroscopic This affinity for water has adverse effects on its thermal insulating
properties However silica powders are now produced with a special treatment which
transforms the material into a hydrophobic material Therefore if these new materials
maintain the thermal properties and density trends of the hydroscopic type they become
even more preferred insulators Once again data needs to be obtained to support this
notion Fumed silica offers a competitive alternative to the existing CFC-blown foams
without the obvious environmental drawbacks It is completely inert recyclable and
reusable It also competes well when comparing cost values CFC-blown foams are
between 003 - 007 $ft2_R-Value whereas fumed silica powder are between 005 -025
$ft2-R-Value The discrepancies are close enough to merit true consideration
AS Thermal Diffusivity Newton-Raphson Iteration Source Code
program difsivty implicit none double precision condqtime(lOO)temp(lOO)guessradiusalpha
+ dif(lOO)sumavedifgcurrentmasslengthpi + density integer nikrun OPEN (2file=Oiffusivityoutlposition=rewind) OPEN (3file=Oiffusivityinposition=rewind) OPEN (4file=Oiffusivityout2position=rewind)
print Enter input current in amps readcurrent printEnter calculated conductivity in Wm K readcond print Enter thermocouple distance in meters readradius print Enter mass of sample in grams readmass print Enter compacted length of sample in em readlength print Enter number of timetemperature data points
65
c
readn 5 print enter initial quess for beta
readquess c
pi=31415927 q=currentcurrent2214 density=(mass1000)laquopi4)(003844)(lenqth100raquo
c c check to see if converqence will occur c print Enter data point l c print (time and temp with a blank separatinq the two) c readtime(1)temp(1) c call diffus(condqtime(1)temp(1)quessradiusalphaq) c printinitial q=q c if (abs(q) qt 05) then c qoto5 c endif c
do 10 i=1n read(3) time(i)temp(i)
10 continue c
print print Input Current= current print write(2) Input Current= current write (2 )
c sum=OO do 20 k=1n call diffus(condqtime(k)temp(k)quessradiusalphaq) print Diffusivity for data pointk =alpha write(2) Diffusivity for data pointk =alpha write(4) alpha dif(k)=alpha sum=sum+dif(k)
20 continue c
avedif=sumn c
print print print INPUT print Conductivity=cond Wm K print Heater Input=q Wm print Thermocouple Distance=radius m print- print OUTPUT print Sample Density=density kqm3 print Averaqe Diffusivity=avedifmiddot m2s
c write(2) write(2) INPUT write(2) Conductivity=cond Wm K write(2) Heater Input=q Wm write(2) Thermocouple Distance=radius m write (2 ) write(2) OUTPUT write(2) Sample Density=density kqm3 write(2) Averaqe Diffusivity=avedif m2s
c c
pause stop
66
end
subroutine diffus(condqtimetempguessradiusalphag) implicit none double precision condqtimetempbeta(100)radius
+ f1f2f1pf2ptempf2tempf2pggppialphaCe + signfactol integer jkmn
c Ce=5772157 pi=31415927 beta (1) =guess tol=l j=l
c c begin Newton-Raphson iteration to find beta and ultimately alpha c
while (tol gt 0001) c print betaj =beta(j)
f1=-Ce20 - log(beta(j)) flp=-l Obeta (j) f2=00 f2p=00
c c start loop to compute the summations for f2 and f2 prime
do 10 k=2162 m=k2
c this loop gives the factorial for the kth term fac=10 do 5 n=lm
fac=facn 5 continue
sign=(-1)laquok+2)2) tempf2=laquobeta(j)k)sign)(kfac) tempf2p=laquobeta(j)(k-1))sign)fac f2=f2+tempf2 f2p=f2p+tempf2p
10 continue
c c compute the value of G and G which are both functions of beta c these will be used to update beta in the Newton-Raphson iteration c where beta(n+1)= beta(n)- GG
g=laquo20picondtemp)q)-(f1+f2) gp=- (flp+f2p)
c print g=g c here we check to see if the convergence criterion suggested c by Nix is met for the initial beta chosen if not we must jump out of loop c if (j eq 1) then c if (abs(g) qt 05) then c printconvergence not satisfied c printtry a s~aller guess for beta c return c endif c endif c c update the value of beta and compute a tolerance value c that will be used to check for convergence
beta(j+1)=beta(j)-(ggp) tol=abs(beta(j+1)-beta(j))
67
j=j+1 c protect against infinite looping
if (j eq 100) then goto 101
endif repeat
c c if the iteration converges then compute the value for diffusivity
alpha=(10(40timeraquo(radiusbeta(jraquo2
c c
101 return
68
APPENDIX B ONE-DIMENSIONAL SIMULATION SOURCE CODE AND OUTPUT
B1 Source Code
CPROGRAM FrigWall--Steady-State Heat Conduction with Convective and CRadiative Heat Transfer from interior and exterior surfaces C Programmed by AM CLAUSING
LOGICAL SI DIMENSION RA(2)XNU(2)R(2)H(2)HR(2)TF(2)TW(2)DT(2) COMMON AXLWXLC(2)HC(2)T(2)XKWBETANMAXSIE(2)SIGMA
CDetermine- direction of output read and print input data NCASE=l
1 CALL DATAIN(NCASEIUOUT) NCASE=NCASE+1 QOLD=O TW(1)=T(1)+1(T(2)-T(1raquo TW(2)=T(2)-1(T(2)-T(1raquo
CCalculate wall resistance RW=XLWXKWA DO 3 N=lNMAX DO S J=12
CCalculate the radiative equivalent heat transfer coefficients HR(J)=SIGMAE(J)(T(J)2+TW(J)2)(T(J)+TW(Jraquo
C Calculate the film temperatures TF(J)=(T(J)+TW(Jraquo2
CCalculate the convective heat transfer coefficients CALL GASPT(lTF(J)RHOXMUXKCPGRBPRIER) DT(J)=ABS(TW(J)-T(Jraquo RA(J)=PRGRBXLC(J)3DT(J) IF(RA(J) LT1E9) THEN
XNU(J)=0S2RA(J)2S ELSE
XNU(J)=09RA(J) 3333 ENDIF H(J)=XNU(J)XKXLC(J) IF(HC(J) NE O) H(J)=HC(J)
CCalculate surface resistances R(J)=l(H(J)+HR(JraquoA
S CONTINUE CCalc~late total resistance heat flow rate and surface temperatures
RT=R(1)+R(2)+RW Q=(T(2)-T(1raquoRT TW(l)=T(l)+QR(l) TW(2)=T(2)-QR(2)
CCheck for convergence If solution has converged exit loop ERRQ=ABS(Q-QOLD)100Q QOLD=Q IF(ERRQLT OS) GOTO 7
3 CONTINUE 7 WRITE (IUOUT 101) Q ERRQ (H (J) HR (J) RA (J) XNU (J) TW (J) DT (J) R (J) RT
2 J=l2) 101 FORMAT( Q =F61 W10XERRQ =FS2 T12 hconvT22hradT33
2 RaT44NuTS2 TsurT62 DeltaTT72RRtotT10 [Wm2-KjT20 2 [Wm2-KjTS3 [KjT63 [Kj InsideF72F92E133F91 2 F101F91F113 OutsideF62F92E133F91F101F91F113) DO 9 J=l2 IF(HC(J) NE bull O) WRITE (IUOUT 103) J
9 CONTINUE 103 FORMAT( NOTE hconv(I1 ) was specified not calculated)
GOTO 1 END
69
C SUBROUTINE DATAIN(NCASEIUOUT) LOGICAL SI COMMON AXLWXLC(2)HC(2)T(2)XKWBETANMAXSIE(2)SIGMA DATA AXLWXKWXLCHCTENMAXSIGMA2990360245315 2 20277297 959510567E-8
CDefinition of NAM NAMELIST NAMAXLWXKWXLCHCETNMAXBETASI CHARACTER FNAME60CDATE9CTIME8 PARAMETER (IUIN=7)
CIF First Case Open Files Write Program Description and Date IF (NCASEEQ 1) THEN
WRITE (6 100) 100 FORMAT( TYPE NAME OF INPUT DATA FILE)
READ( (A) ) FNAME COpen input and output files
OPEN (7FILE=FNAME) REWIND 7
C OPEN (10FILE=Plots-FNAME) C WRITE(6122) Plots-FNAME C122 FORMAT( COMMA DELIMITED PLOTTING FILE IS A)
WRITE(6118) 118 FORMAT (T10 DIRECT OUTPUT TOT20 SCREENT36 Type 6
2 T20 OUTPUT FILET36 Type 8T20 PRINTERT36 Type 9) READ() IUOUT IF(IUOUTEQ8) THEN OPEN (8FILE=Answers-FNAME) WRITE(6120) Answers-FNAME
120 FORMAT( OUTPUT WILL BE WRITTEN IN FILE A) ENDIF CALL DATE(CDATE) CALL TIME(CTIME)
CWrite Program Description and Date WRITE(IUOUT102)CDATECTIME
102 FORMAT( Program FrigWallT60 Date A10 Version 8 August 1991T60 2 Time A9 Programmed by AMClausing) ENDIF
CRead and Write Input Data READ(IUINNAMEND=999) WRITE (IUOUT 104) NCASETXLCEXLWXKWA
104 FORMAT ( CASE NUMBER 12 2 Ambient Temperatures IK] InsideF616X OutsideF61 2 Characteristic Lengths 1m] InsideF626X OutsideF62 2 Surface Emissivities8X InsideF626XOutsideF62 Wall
Thickness 2 F63 mT27 ConductivityF63 Wm-K2x AreaF52 m2) RETURN
999 WRITE (IUOUT 199) 199 FORMAT ( ALL INPUT DATA HAS BEEN PROCESSED) 991 CLOSE(10)
IF(IUOUTEQ 8) CLOSE(8) STOP END
C SUBROUTINE GASPT(NGASTRHOXMUXKCPGRBPRIER)
C PROGRAMMED BY A M CLAUSING VERSION APRIL 1982 C PROPERTIES OF GASES IN SI UNITS(TGTO) OR ENGLISH UNITS(TLT O) C FUNCTIONAL REPRESENTATIONS USED ARE OF THE FORM Y=ATB C ARRAYS A AND B CONTAIN THE RESPECTIVE CONSTANTS C INPUT C NGAS - NGAS=l IS AIR NGAS=2 IS NITROGEN C T ---- ABSOLUTE TEMP (K) OR NEGATIVE OF ABSOLUTE TEMP (R) C OUTPUT C RHO -- DENSITY (KGM3) OR (LBMFT3)
70
C XMU -- VISCOSITY (KGM-S) OR (LBMFT-S) C XK --- THERMAL CONDUCTIVITY (WM-K) OR (BTUHR-FT-R) C CP --- SPECIFIC HEAT (JKG-K) OR (BTULBM-R) C GRB -- GBETAXNU2 (1M3-K) OR (1FT3-R) C PR --- PRANDTL NUMBER (DIMENSIONLESS) C IER -- ERROR PARAMETER C INFORMATIVE ERRORS C IER=l --- GAS NUMBER DOES NOT EXIST GAS IS ASSUMED TO BE AIR C IER=2 --- TEMPERATURE OUT OF RANGE OF PROPERTY SUBROUTINE C RESTRICTIONS C NGAS -- MUST BE l(AIR) OR 2 (NITROGEN) C T ----- T MUST LIE BETWEEN 150K AND 2100K FOR AIR AND BETWEEN C 83K AND 450K FOR NITROGEN RANGES ARE SPECIFIED WITH ARRAY R C
DIMENSION A(152)B(152)R(32) DATA A36411764E-61423E-399084178E20123 235064914E-62494E-329944985E195930 3 432491E-81239E-415534379E201137 4351618E-6221E-31031408E2084130 DATA B-1005814913800316-4639-09685 2 -999642981521962-4284023930 3 -10469389466-079-5102-0872 4 -10058058 834500239-4636-0265230 DATA R150400210083160450 IER=O IFlaquoNGASGTO) AND(NGASLT3raquo GO TO 1 IER=l NGAS=l
1 1=1 TP=T IF(TLT bullbull O) TP=-T18 IFlaquoTPLTR(lNGASraquo OR (TPGTR(3NGASraquo) IER=2 IF(TPGTR(2NGASraquoI=7 RHO=A(INGAS)TPB(INGAS) XMU=A(I+1NGAS)TPB(I+1NGAS) XK=A(I+2NGAS)TPB(I+2NGAS) CP=A(I+3NGAS)TPB(I+3NGAS) GRB=A(I+4NGAS)TPB(I+4NGAS) PR=A(I+5NGAS)TPB(I+5NGAS) IF(TGT O)RETURN RHO=RHO1602 XMU=XMUl 488 XK=XKl 731 CP=CP4187 GRB=GRB6357 RETURN END
B2 Output
Program FrigWal1 Version 8 August 1991 Programmed by AMClausing
Date Time
05-MAR-92 200227
CASE NUMBER 1 - Fresh Food Walls
Ambient Temperatures IK] Inside 2770 Outside 2940 Characteristic Lengths 1m] Inside 030 Outside 150 Surface Emissivities Inside 095 Outside 095
71
Wall Thickness 0045 m Conductivity 0027 Wm-K Area 242 m2
Q = 209 W ERRQ = 002
hconv [Wm2-K]
Inside 1 98 Outside 130
hrad [Wm2-K] 461 544
Ra
0488E+07 0459E+09
Nu
244 761
Tsur [K]
2783 2927
DeltaT [K] 13 13
RRtot
0077 0075
CASE NUMBER 2 - Fresh Food Door
Ambient Temperatures [K] Inside 2770 Outside 2940 Characteristic Lengths [m] Inside 030 Outside 150 Surface Emissivities Inside 095 Outside 095 Wall Thickness 0040 m Conductivity 0040 Wm-K Area 089 m2
Q = 117 W ERRQ = 001
hconv [Wm2-K]
Inside 218 Outside 144
hrad [Wm2-K] 463 542
Ra
0714E+07 0690E+09
Nu
269 843
Tsur [K]
2789 2921
DeltaT [K]
19 19
RRtot
0114 0113
CASE NUMBER 3 - Freezer Walls
Ambient Temperatures [K] Inside Characteristic Lengths [m] Inside Surface Emissivities Inside
2630 030 095
Wall Thickness 0056 m Conductivity 0027
Outside Outside Outside
2940 150 095
Wm-K Area 110 m2
Q = 14 3 W ERRQ = 003
hconv [Wm2-K]
Inside 226 Outside 143
hrad [Wm2-K] 397 542
Ra
0990E+07 0684E+09
Nu
292 841
Tsur [K]
2651 2921
DeltaT [K]
21 19
RRtot
0067 0061
CASE NUMBER 4 - Freezer Door
Ambient Temperatures [K] Inside 2630 Outside 2940 Characteristic Lengths [m] Inside 030 Outside 150 Surface Emissivities Inside 095 Outside 095 Wall Thickness 0040 m Conductivity 0040 Wm-K Area 034 m2
Q = 81 W ERRQ 002
hconv [Wm2-K]
Inside 259 Outside 1 64
hrad [Wm2-K] 400 538
Ra
0169E+08 0124E+10
Nu
333 967
Tsur [K]
2666 2906
DeltaT [K] 36 34
RRtot
0117 0110
72
__ ___
APPENDIX C TEST REFRIGERATOR DESCRIPTION
The test refrigerator is a White-Westinghouse model RT193MCWO 186 cubic foot
capacity top-mounted unit It is equipped with full automatic defrost The cycle time for
this unit is approximately 50 The unit also has two anti-sweat devices An electric
heater is located in the mullion region to prevent frosting between the freezer and the fresh
food compartments Also a condenser tube runs around the entire outside perimeter of the
unit embedded beneath the steel all flange Figure C1 illustrates these features
~1-- 0787 m (31)__
~ r_----------------------
1581 m
Fig CI Location of Anti-sweat Devices and Overall Dimensions of Test Refrigerator
73
Under test conditions the refrigerator and freezer are filled with milk containers full of
water These containers provide sufficient thennal mass to minimize temperature
fluctuations dming experimental runs Twenty gallons are present in the fresh food
compartment and 6 gallons are in the freezer
Figures C2 through C5 give the detailed dimensions of the fresh food compartment and
the freezer All dimensions are in millimeters and are obtained directly from the unit
Dimensions are estimated to be accurate to within plusmn 3 mm
697
762
1
305
717
Fig C2 Fresh Food Compartment Interior Dimensions
74
1127
Fig C3 Fresh Food Door
75
675
381
Fig C4 Freezer Interior Dimensions
432
Fig CS Freezer Door
76
APPENDIX D DATA ACQUISITION AND CONTROL SYSTEM
Corresponding with the construction of the experimental apparatus was the purchase and
assembly of a data acquisition and control system The system itself was designed to meet
the needs of a variety of experiments and is therefore a very flexible system
The system consists of six DC power supplies a data acquisition chassis a computer a
rack ofdigital relays and a variety of analog and digital inputs and outputs A data
acquisition and control software package orchestrates the interactions between these
components and regulates outgoing signals as well as providing data storage
External signals enter the system through a Keithley 500P data acquisition chassis These
signals consist of voltage and current measurements from the power supplies as well as
thermocouple voltages At present a total of ninety-six thermocouple inputs are available
with an optimal resolution of +0012 degrees C The addition of more thermocouple input
boards could expand the capability to 128 inputs Also special boards can be installed to
allow strain gauge thermistor digital or other standard data acquisition functions The
Keithley chassis can contain a total of nine interface boards and its l~bit AID conversion
allows for very high resolution
The six DC power supplies consist of two Hewlett Packard and four Sorensens with a
combined power of 7560 watts The Sorensens are rated at 0-150 volts at a maximum of
12 amps while the Hewlett Packards produce 0-60 volts at a maximum of 3 amps All of
the power supplies are computer-controlled however the Sorensens may be operated
manually ifdesired Voltage measurements from the power supplies are fed into the
Keithley acquisition chassis and are then routed to the computer A voltage from the
computer is buffered and fed into the control circuits of the power supplies This voltage
completes the loop and controls the output voltage of the power supplies The software is
responsible for reading the output voltage of the power supplies comparing it with the
intended setpoint and adjusting the control voltage as needed This arrangement allows the
user to vary the output voltage of the power supplies from within a program Computershy
controlled safety relays are in place to disconnect the power supplies should they stray too
far from the intended voltage setpoint Fig D1 displays the system
77
Thermocouple and Voltage Inputs
r
Computer Data Acquisition Chasis Intaface
00 Voltage and 1 r Current
Measurement
Computer
I I
Analog Control Signal
Digital Oulput Signals 5 6
Power Supply 4 Relay Rack
Power Supply 3 00000001 Power Supply 2
Buffered Analog100000001 Power Supply 1 Control Signal
1 2 3 4 5 6 - I
I00 00 )0 po po po
Ir Digital Outputs
Analog Outputs
Fig DI Data Acquisition and Control System
78
APPENDIX E EXPERIMENTAL RAW DATA AND PLOTS
E1 Temperature Profile Plots From Fixed Thermocouples
In this appendix the remaining tests for the fixed thennocouple testing presented in Section
41 are provided Figures E1 and E2 give the results from the fresh food compartment
and Figures E3 and E4 give the results from the freezer Notice the outdoor and interior
ambient temperatures are not the same as the two tests presented in Section 41
191
Run 2 ttl ~ i i
middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot
middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot-imiddotmiddot
TWall
middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotlmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot
-
Outdoor Ambient =210 degC Fresh Food Ambient =375 degC
-] _ Door ProfUe i -il- 0 Wall Profile
i 19
$-- - Tdo = 19078 - 001326x
l~l ~~i 189 i i a m
0 i -m-
i 188 middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot
187 ~ middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot 5 = 18989 - O02024x 1
F 186
~bullbullbullbullbullbullbullmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot185 i i
184 0 5 10 15 20 25
x (mm)
Fig E1 Steel Skin Temperature Plot for Fresh Food Compartment (Run 2)
79
191
19
189
a ~
i 188
187
5F
186
185
184 0
Run 3 I --D - Door Profile
middotmiddotmiddotmiddotmiddotmiddotmiddotmiddot-middotmiddotmiddotmiddot~middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotimiddotmiddot-middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddot 0 Wall Profile
i - i - - Tdo =19053 - 001384x or
=c-=r=-~-= 1 11=
~ n - 189S 001998 --t-shy-~~-
5 10 15 20 25
x (mm)
Fig E2 Steel Skin Temperature Plot for Fresh Food Compartment
186
184
182
- ~- 18
178
~ 176
174
172 0
(Run 3)
Run 2 l --0 - Door Profile
middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot~middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotdrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotf 0 Wall Profile - 1- - middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot--m
- - T =18544 - 002398x i - i door rb
~i
i bullbullbulli _ bull imiddot
~ I TWall =18182 - 003542x tmiddotmiddotmiddotmiddot middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotlmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot
~ n~l l
5 10 15 20 25
x (mm)
Fig E3 Steel Skin Temperature Plot for Freezer (Run 2)
80
--a 0
I5F
186
184
182
18
178
176
174
172
Run 3 I --0 - Door Profile
middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotCmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotl 0 ~a1l Profile
ttl __ OJ 1 1 middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotfmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotlmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot -shy - Td = 18411 - 002272x ibullbullbullbullbullbullbull-bullbullbullbullbullbullbullbullbulli
oor ~
rp bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbull bull 11_1
I I middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotimiddotmiddotmiddotmiddot middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotImiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot
~ _l
Outdoor Ambient =208 degc Freezer Ambient = -93 degc
0 5 10 15 20 25
x (mm)
Fig E4 Steel Skin Temperature Plot for Freezer (Run 3)
E2 Thermopile Data Reduction
The data from the thennopile tests consist of an output voltage (mV) measured with a
Keithley multimeter which has a resolution of 1 m V The procedure required to translate
this voltage into a temperature difference follows
1 Read the output voltage in millivolts
2 Detennine the average skin temperature from fixed thennocouple data
3 Use the reference table and the average skin temperature to determine the conversion factor in Vrc
4 Convert to temperature difference as follows
1T = ____o_utpu_t_vo_l_tag-e___
ofjunctions x conversion factor
81
Table EI Thermopile Raw Data
ffOutput fzOutput ff Ave Skin Temp fz Ave Skin Temp mV mV CC CC
Roo wall door wall door wall door wall door
1 0052 0048 0045 0050 189 191 177 183
2 0054 0052 0046 0048 187 189 176 182
3 0056 0053 0046 0051 186 188 175 181 ff Conv Factor fz Conv Factor ff AT fzAT
Ilvrc Ilvre CC CC
Roo wall door wall door wall door wall door
1 40165 40181 40067 40116 026 024 037 041
2 40148 40165 40058 40107 027 026 038 040
3 40140 40157 40050 40099 027 026 038 040
Average Temperature Difference 0267 0377 0253 0403
from Thermocouple Reference Tables Based on the IPTS-68 US Dept of Commerce
E3 Experimental Determination of qwall and qdoor Details
The four heat fluxes are calculated using
-k M (El)q - m Ax
For 05 carbon cold rolled steel km =540 Wm K (312 Btuhr-ft-OF) Also Ax = OOlm (039 in) for all computations
0267degC 2 qwallff = 54 Wm-K 001 m = 14418 Wm
_ 0377 degc _ 2 qwallfz - 54 Wm-K 001 m - 20358 Wm
0~3~ 2 qdoorff =54 Wm-K 001 m =13662 Wm
82
0403degC 2 qdoorfz = 54 Wm-K 001 m = 21762 Wm
Compute the heat transfer rate according to Equation (B2)
q =qA=qhP (B2)
Where A is the cross sectional area of the steel casing that is perpendicular to the direction
of heat flow The area is the product of the steel skin thickness b and the total perimeter of
the compartment opening which is exposed to the room environment P Perimeter
definitions
Pwallff = llm + 076m +llm = 296 m
roJ D Pwallfz =O4lm + 076m + O4lm =l58 m
I ] I ~I Pdoorf( = llm + 076m + llm + 076m = 372 m
Pdoorfz =076m + O4lm + 076m + 041m =234 m
83
qwallff =(14418 Wm2)(65e-4 m)(296 m) =277 W
qwallfz =(20358 Wm2)(65e-4 m)(158 m) =209 W
qdoorff =(13662 Wm2)(65e-4 m)(372 m) =330 W
qdoorfz =(21762 Wm2)(65e-4 m)(234 m) =331 W
E4 Temperature Profile Plots From Mullion Data (Heater oro
The following plots are from the remaining runs for the mullion analysis presented in
Section 45 All data is taken from the exact center of the mullion
131
13 middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot-tmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotjmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotlmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot9middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotlmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot6middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddot T 11 f =12383 + 0019929x iii mu z
129 ~ middotImiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot[middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddota ~
i 128 middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot4middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot-j-middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotfmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotfmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot
127e ~
126 ~~~=H~~-~=HmiddotrI~ ++~11 Room Ambient =2250 degC125
1 1 i Fresh Ambient =515 degC iii i i Freezer Ambient =-603 degC
124
1 10
Fig ES Mullion Temperature Profile Run 2 (Heater Off)
Run 2
2 3 4 5 6 7 8 9
TIC
84
146
145
a 144 ~
i 143
5 ~ 142
141
Run 3 9 0
---r-r--deg-r-ideg-t-9--rshyiii ltD T 11 ff = 15173 - OOI71x mu bull
middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotfmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotImiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot6middotmiddot
1Tmull~fz =14062 + J0158211x JLt 1
Q 1 1 1 middotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1-middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddoti-middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotimiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotoot-middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot-I-bullbullbull~bullbullbullbullbullbullbullbullbullbullbull
iii middotiiimiddot-j Room
1Am~t = 21~1 degC
iii i 1 Fresh Ambient = 563 degC 1 1 1 1 1 Freezer Ambient = -153 degC
14~---+--~----r---+---~---+--~----r---+-
1 2 3 4 5 6 7 8 9
TIC I
Fig E6 Mullion Temperature Profile Run 3 (Heater Off)
127
126
125 a ~
i 124
123 e ~
122
121
12
1
Fig E7
i i CD middotmiddotmiddotmiddot----middotmiddot-r--middot---middotmiddotmiddotmiddotmiddotmiddot-lmiddot--------middotmiddotmiddotmiddotl-middotmiddot---middotmiddotmiddotmiddot---r---middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1middotmiddotmiddotmiddotmiddot---middotmiddot---middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot-r----middot1__ _-
I I I T mulIff = 1321 - 001532x middotmiddotmiddotmiddot------middott--------------tmiddotmiddot----middot----middotmiddot-1------middotmiddotmiddotmiddotmiddotmiddot---jmiddot-----middotmiddotmiddotmiddotmiddotmiddotmiddotmiddot-lmiddotmiddotmiddot---middotmiddotmiddot-----tmiddotmiddotmiddotmiddotmiddot--middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddot-----middotmiddotmiddot6middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot
I cent I I I I -~~~~-ro-Tr-
r-middotmiddotmiddotmiddotrTTr-middotrmiddotrmiddotrmiddot middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddott middotmiddotmiddottmiddotmiddot1middotmiddotbullbullbullbull fmiddotbullbullbullbullbullbullbullmiddot-fbullbullbullbullbullbullbullmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot
II Room Ambil =21~3 degC iii i i Fresh Ambient =551 degc iii i i Freezer Ambient = -681 degC
2 3 4 5 6 7 8 9 10
TIC I
Mullion Temperature Profile Run 4 (Heater Off)
85
10
111
iii i i 11
Fttul5
T mu
=J=~[rr~tl=rI=109
a ~ 108 -t-t-t-i~FFl~i~~
+-0amp_- -+_bullbullbullbullbullbullbullbull+ - bullbullbull 107 11 f ~ 10325 + 0021893x 1 1 1 ji
5 bull Z iii
------~-~-----~---i --L--l ---_l__ ---L-----_shy106 ~
105 -t---i--+-+-+-middot++-I-shyL1LLL Room Ambient = 2177 C104 iii i i Fresh Ambient =448 degC
Freezer Ambient = -644 degC 103
1 2 3 4 5 6 7 8 9 10
TIC
Fig E8 Mullion Temperature Profile Run 5 (Heater Off)
86
34
33 1 1 1 1 1 1 1 1------I---------middotmiddot--+middotmiddotmiddotmiddot------middottmiddot-------middotmiddotmiddotmiddottmiddot----------middotmiddotmiddot---middot---middot----tmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot---middotmiddott--middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot(middotmiddotmiddotmiddotmiddot--
32 11 f =1 2859 ~ OI~X j
Till ff =133013 j - 007124x mu
31
a ~ 30
i 5 ~
29
28
27
26
Tmullfz = 26944 + 014842x
mu t-tr l
25 middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotjmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotjmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotlmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1middot ~ u~ ~it
24 lllti1 ~ i i ~ i
0 Lower Limit
23
0 1 2 3 4 5 6 7 8 9 10
ES Temperature Profile Plots From Mullion Data (Heater On)
The following are the remaining plots from the mullion heater analysis presented in Section
46
TIC I
Fig E9 Mullion Temperature Profile Run 2 (CenterHeater On)
Run 2
T muz
1
87
l----+
29
middotmiddotmiddotgtmiddotmiddoti middot 0 upper Limit 28 Run 1
I
middotmiddotI o
Tmullfz
T muo
LL~4cb 0 Lower Limit27
middot~+ImiddotmiddotmiddotImiddotmiddotmiddottr9middotdJmiddotmiddotmiddotmiddot 26
t T = 29465 008022xmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddot1middotmiddotmiddotmiddotTmiddotmiddotmiddotmiddot[middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1middot mullffa 25~
i 24 =24837+ 013186x middotlmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot+middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotimiddotmiddotmiddotmiddotmiddotmiddotmiddotlmiddotmiddotmiddotmiddotmiddotmiddot iii i i
i _ Jbullbullbullbullbullbullbullbullbullbullbullbullbulli l _l ii 23
e 22~ 21 +I~=tt=l=fit
L~LLL Tm~llff = 23856 005858x20 11 f = 1803 + 02243x z -rmiddotmiddotmiddotmiddot1middot middotmiddot middotmiddot 1middotmiddotmiddotmiddotmiddotTmiddotmiddot middot-rmiddot19
18
0 1 2 3 4 5 6 7 8 9 10
TIC
35
34
33
32
a ~ 31
I ~
30
29
28
27
26
25
24
Fig EI0
---bull---i----bullbullmiddotmiddotmiddotmiddot--~--------middotmiddot-+------ j bullbullbullbull ---bullbullbullbull -i--__---
T 11 f =30063 + OI~x 1 T i 134 196 i
0068 1 38
muz tmiddotmiddot Ilff=middot bull x ltP lt1gt mu
=t=H=t+t=R=t= F-6~I-i~E
Tmullfz = 28103 + 014486x 1middot++middot1middot1
middotmiddotmiddot--middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotimiddotmiddotmiddotmiddotmiddotmiddotmiddot-middotmiddotmiddotmiddotmiddot+middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotbullbullmiddotmiddotmiddot-middotmiddotimiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot~middotmiddot
111111 0 Upper Limit iii iii 0 Lower Limit
0 1 2 3 4 5 6 7 8 9 10
TIC
Mullion Temperature Profile Run 3 (CenterHeater On)
Fig Ell Mullion Temperature Profile Run 1 (LeftHeater On)
88
a
29
28
27
26
25~
i 24
23 e
22~ 21
20
19
18
Fig E12
i l middot middotmiddotmiddotmiddotlmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot+ 0 Upper Limit T 11 f =24474 + 011288x i imu bull z o Lower Limit
=tplusmntplusmnfrplusmnplusmnplusmn ~ I I I I Tmull ff ~ 28793 - o0784x
middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddott----middot------middotmiddotimiddot----middot-middotmiddot--middot-~-middotmiddotmiddot--middot----middotmiddot)middot
=ii=t=1=P-Ltplusmnt iii i T = 25599 - 00689xIfmiddotTTTmiddotmiddotrmiddot ~Ullff iii
T l1f =20552 + 01676x i~~imiddotimiddotmiddot
==~LL L LLLLL i i 1 ~ 1 ~
0 1 2 3 4 5 6 7 8 9 10
TIC I
Mullion Temperature Profile Run 2 (LeftlHeater On)
33 iii i i
-middot--middot(---middotmiddot--middotmiddot--middotmiddot+---middot-middotmiddotmiddotmiddot-middotmiddotmiddot~-middot--middot-------middoti---middot------~ o Upper Limit 32 Run 3
t bullbullbull +
Tm~llfz
T mu
1 1 1 1 1 o Lower Limit ~~31
=2713 ~ 0113~x j11Li30
a T ulff =30658 - 006506x 29~
IktlJ2~Li 28
27 e
26 =l=tt=tmiddotmiddottmiddott+~middot+=t=~ middotmiddot jmiddotjmiddottmiddottmiddotjmiddot T = 28288 - 00603x
iii i mullff 24
25
middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotQmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot+middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot~middotmiddotmiddot middotmiddotmiddotmiddotmiddotmiddotmiddotmiddot~middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot+middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot 11 fz = 2377 ~ 01788x IL11123 i i
22
0 1 2 3 4 5 6 7 8 9 10
TIC I
Fig E13 Mullion Temperature Profile Run 3 (LeftHeater On)
89
31
30
29
ltP ~u
J
1 T
-~Lti=t~-t--t i~+--Ij Tmu1lff =31473 middot005222x 28
1 1 1middot 1 l i l i bullbullbullbullbullbullbull__ bullbullbullbull_ bullbullbullbullbullbullbull~_bullbullbullbullbullbullbullbullbulla bullbullbullbullbullbullbullbullbullbullbull a 27
~ Tm~llfz = 26857 + 01734x _~__+_+II i
26
bullmiddotmiddotbullbullbullmiddotmiddotbullibullbullbullbullbullbullbullbullbullbullbullmiddotmiddotmiddotbullbullbullbullbullbullbullbullmiddotmiddotmiddotmiddot bullbullbullbullbullbullbullbullbull-i-~-i-ii25
JJ$~L-f$9 5 24
~ 23 middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotlmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot+middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot~middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot+middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1-middotmiddot T mllff =25622 bull 002~7X c-bullbullbullbullbullbullbullbullbullbullbullbull+ ~~ 22 rp 1 1 i i 1 1 1
21 = 19464 + 02548 jmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddott Upper Limitmullfz xii 0
4-bullbullbullbullbullbullbullbullbullbullbullbullimiddotmiddotmiddotbullbullbullbullbullbullmiddotf20 i 1 ~ 1
19
0 1 2 3 4 5 6 7 8 9 10
TIC I
Fig E14 Mullion Temperature Profile Run I (RightHeater On)
33 i
middotmiddotmiddotmiddotlaquomiddotmiddotmiddotmiddot------------------------------- c--------middotmiddotmiddot-middot-----------middotmiddotmiddot---middotmiddot--------l-----middot-----I-----32
= 2757 + 017006x ILLJ1
a
31
30
29~
i 28
Run2
TmulIfz
T~ulIfz ~
-~t=ii~Ii~~~~ i
27 middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot9-middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotT~~middotmiddotmiddotmiddotmiddot2s944-middot~middotmiddotO0278~middotmiddote 26~ r~rrTt+rr25
24 2320~ + O~S4x middotmiddotlmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotjmiddot ~ u~ L~t 23 middotmiddotmiddotmiddotmiddotmiddotmiddotmiddot~middotmiddotmiddotmiddotmiddotmiddotmiddot+middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot+middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot+middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotImiddotmiddotj 0 Lower Limit
22
0 1 2 3 4 5 6 7 8 9 10
TIC I
Fig EIS Mullion Temperature Profile Run 2 (RightlHeater On)
90
33 i i ~ _______ _ _~____ __ __-i--bullbullbullbullbullbullbullbull-t------ -- uu__~ ~ --~32
=1268931+ 0~4~14X 111131
30
a 29~
I 28
Run3
Tmullfz
i t+ I T
m
mnplusmn~~27 6 i 1 i 1 +++ T mullff =28912 - 002938x 26~ +middotmiddot++Imiddotjmiddott-25
= 22996 + 02312x 1middotmiddot+ 24
~~~~L lL1 0 ~23 ill 0 22
0 1 2 3 4 5 6 7 8 9 10
TIC
Fig E16 Mullion Temperature Profile Run 3 (RightHeater On)
91
APPENDIX F NUMERICAL SIMULATION EQUATIONS AND CODE
F1 Finite-Difference Equations
Figure Fl is a generic resistor network that is used as a base for all the finite-difference
equations The general fonn is
(Fl)
r----II ij+l
J
i j-l L ______--J
Fig F1 Generic Nodal Resistor Network
This makes it easy to simply plug in the different resistors for the different regions of the
section There are twelve resistors total The following table summarizes the resistors
needed to complete the model
Table F1 Model Resistors
Description Resistance [CIW]
Interior insulation x direction Rl= dx dymiddotkinsmiddotb
92
dyInterior insulation y direction R2= dx-kins-b
dySteel parallel with insulation y direction R3= km-dm-b + kins-(dx -dm)
dxR=Steel parallel with insulation x direction km-dm-b + kins-(dy -dm)
dyRs=Plastic parallel with insulation y direction
kp-dp-b + kins-(dx -dp)
dxPlastic parallel with insulation x direction R6= kp-dp-b + kins-(dy -dp)
heffa- (~- dm) + kinsSteel to exterior x direction R7= 2
heffo-kins-dy-b
heffa- (dY - dm) + kinsSteel to exterior y direction R - 28shyheffo-kins-dx-b
hefti- (dY _dm) + kinsSteel to interior y direction R9= 2
heffi-kins-dx-b
hefti- (~- dp) + kinsPlastic to interior x direction RIO= 2
heffi-kins-dy-b
Rll = hefti- (dJ -dP) + kinsPlastic to interior y direction
heffi-kins-dx-b
93
Steel skinplastic skin interface
2middotkmmiddotdmmiddotkpmiddotdpmiddotdxR12=----------------------~~----------------
2middotkmmiddotdmmiddotkpmiddotdpmiddotbmiddot(dy -dp) + (kpmiddotdp + kmmiddotdm)middotbmiddotdx2
F2 Wall Simulation Source Code
Program FiniteDiff
c This program simulates the conductive heat transfer through the wall section c of the refrigerator near the door gasket using Guass-Siedel iteration c The program allows for flexibility in the geometry and material properties c The program is a steady-state model
cVariable Definitions
c km = conductivity of the outer metal skin (Wm-K) c kins = conductivity of the polyurethane foam insulation (Wm-K) c kp conductivity of the inner plastic skin (Wm-K) c dm = thickness of the metal skin (mm) c dp = thickness of the plastic skin (mm) c b = depth of the section (m) c heffo = effective heat transfer coefficient on outside surfaces (Wm2-K) c heffi = effective heat transfer coefficient on inside surfaces (Wm2-K) c sl width of wall inSUlation (mm) c s2 length of wall section (mm) c s3 seal indentation (mm) c s4 seal width (mm) c s5 distance metal skin travels into cabinet (mm) c s6 distance platic skin travels out of cabinet (mm) c ns = number of nodes corresponding to the s regions above c rs = network resistors (m-eW) c i = integer values of distance along the x axis c j = integer values of distance along the y axis c imax maximum integer value in x direction c jmax maximum integer value in y direction c iter total number of iterations to converge c loop convergence flag c Qinl Heat flux per unit length across the outer boundary (Wm) c Qin2 Heat flux per unit length across the inner boundary (Wm) c Qdif Qinl - Qin2 (Wm) c Qpdif = percent difference between the heat fluxes Qinl and Qin2 c Ti Inside ambient temperature (e) c To = Outside ambient temperature (e)
cDeclare Variables
INTEGER nln2n3n4n5n6ijloopimaxjmaxiter INTEGER clflaglflag2 REAL kmkinskpdmdpdxdyheffoheffi REAL TiToQdifQpdifQinlQin2 REAL sls2s3s4s5s6lenoutlenin REAL rlr2r3r4r5r6r7r8r9rlOrllr12 REAL T(-1lOl-1lOl)bqlDsumlsum2 REAL Qm(lOl)qfluxm(lOl)fluxo(OlOl)fluxi(OlOl)
94
REAL fluxcen(0101)pfluxcen(0101)pfluxo(0101) REAL pfluxi(0101)pmaxdifoneDtolaq2Dqedge1
OPEN (10file-2Dcode(v11)out1position-rewind) OPEN (11file-2Dcode(v11)out2position=rewind)
cTest Parameters
c thermal conductivity of the outer metal skin (Wm K) km-540
c thermal conductivity of the wall insulation (Wm K) kins=0021
c thermal conductivity of the inner plastic skin (Wm K) kp=015
c thickness of the metal skin (mm) dm=065
c thickness of the plastic skin (mm) dp=25
c effective heat transfer coefficient on outside surfaces (Wm2-K) heffo=681
c effective heat transfer coefficient on inside surfaces (Wm2-K) heffi=610
c width of section (mm) sl=450
c length of section (mm) s2=2000
c depth of the section (m) b=10
c inside ambient temperature (C) Ti=95
c outside ambient temperature (C) To=210
c unit conversions dm=dm1000 dp=dp1000 sl=sl1000 s2=s21000
c specify 1-dimensional tolerance (t) oneDtol=30
cMesh Parameters
c specify the following nodal mesh parameters n1=20 n2=80 n3=1 n4=9 n5=10
c various mesh dimensions dx=sln1 dy=s2n2 s3=n3dx s4=n4dx s5=n5dx s6=sl-s5-dx n6=s6dx imax=n1-1 jmax=n2-1
cInitialize temperature matrix
DO 10 j=-1jmax+1 DO 20 i=-1imax+1 T(ij)=Ti
95
20 CONTINUE 10 CONTINUE
DO 30 j=Ojmax T(-Ij)=To
30 CONTINUE
DO 40 i=0n3 T(i-I)=To
40 CONTINUE
DO 50 j=Ojmax T(imax+lj)=Ti
50 CONTINUE
DO 60 i=n3+n4+1imax T(i-I)=Ti
60 CONTINUE
cResistors [m-CW]
c interior insulation x direction rl=dx(kinsdy)
c interior insulation y direction r2=dy(kinsdx)
c metalinsulation y direction r3=dy(kmdm+kins(dx-dm))
c metalinsulation x direction r4=dx(kmdm+kins(dy-dm))
c plasticinsulation y direction r5=dy(kpdp+kins(dx-dp))
c plasticinsulation x direction r6s dx(kpdp+kins(dy-dp))
c metal to exterior x direction r7=(heffolaquodx2)-dm)+kins)(heffokinsdy)
c metal to exterior y direction rB=(heffo laquody2)-dm) +kins)(heffokinsdx)
c metal to interior y direction r9=(heffilaquody2)-dm)+kins)(heffikinsdx)
c plastic to interior x direction rl0=(heffilaquodx2)-dp)+kins)(heffikinsdy)
c plastic to interior y direction rll=(heffilaquody2)-dp)+kins)(heffikinsdx)
c metalplastic interface rI2=(2kmdmkpdpdx)(2kmdmkpdp(dy-dp) + (kpdp+km dm)dxdx)
cxxxxxGuass-Siedel Iterationxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx loop=1 iter=1 DO WHILE (loop eq 1)
c Equations for row 0 i=O j=O CALL sseqn(Tr4r7r3rBijimaxjmax)
DO 70 i=ln3 j=O CALL sseqn(Tr4r4r2rBijimaxjmax)
70 CONTINUE
DO 75 i=n3+1n5-1
96
j=O IF (i le n3+n4) THEN
CALL sseqn(Tr4r4r21e20ijimaxjmax) ELSE
CALL sseqn(Tr4r4r2r9ijimaxjmax) ENDIF
75 CONTINUE
i=n5 j-O IF (i le n3+n4) THEN
CALL sseqn(Tr12r4r21e20ijimaxjmax) ELSE
CALL sseqn(Tr12r4r2r9ijimaxjmax) ENDIF
i=n5+1 j=O IF (i le n3+n4) THEN
CALL sseqn(Tr6r12r21e20ijimaxjmax) ELSE
CALL sseqn(Tr6r12r2rllijimaxjmax) ENDIF
DO 80 i=n5+2imax-l j=O IF (i le n3+n4) then
CALL sseqn(Tr6r6r21Oe20ijimaxjmax) ELSE
CALL sseqn(Tr6r6r2rllijimaxjmax) ENDIF
80 CONTINUE
i=imax j=O CALL sseqn(TrlOr6r5rllijimaxjmax)
c Equations for rows 1 thru jmax-l DO 90 j=ljmax-l
i=O CALL sseqn(Tr1r7r3r3ijimaxjmax)
DO 100 i=1imax-1 CALL sseqn(Tr1r1r2r2ijimaxjmax)
100 CONTINUE
i=imax CALL sseqn(Tr10r1r5r5ijimaxjmax)
90 CONTINUE
c Equations for row jmax j=jmax i=O CALL sseqn(Tr1r710e20r3ijimaxjmax)
DO 110 i=1imax-1 j=jmax CALL sseqn(Tr1r110e20r2ijimaxjmax)
110 CONTINUE
i=imax j=jmax CALL sseqn(Tr10r11Oe20r2ijimaxjmax)
97
c c c
Compute the difference in heat flux crossing the outer boundary and crossing the inner boundaryr ideally the difference should be zero
CALL balance(TToTidxdyn3n4imaxjmaxQdifQpdif c QinlQin2r7r9r8rlOrllb)
c Update loop variables iter-iter+l
c Convergence criterium IF (Qpdif le 20) then
loop-O ENDIF IF (iter eq 10000) THEN loop=O write(lO) Solution did not converge
ENDIF
END DO cxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
cHeat Transfer Calculations
c Compute 10 heat flux through wall CALL oneD (ToTiheffoheffikmkinskpdmdpslqlD)
c Compute the flux thru wall at each node on the c outside and inside walls [Wm2) Also the flux c in the x-direction across the center line of the c section
cl-int(nl2) fluxcen(0)=(1(r4dy))(T(cl0)-T(cl+l0)) fluxo(0)=(1(r7dy))(To-T(00)) fluxi(O)=(l(rlOdy))(T(imaxO)-Ti) DO 112 j=ljmax
fluxcen(j)=(l(rldy))(T(clj)-T(cl+lj)) fluxo(j)=(1(r7dy))(To-T(0j)) flumiddotxi (j) =(1 (rlOdy)) (T (imax j)-Ti)
112 CONTINUE
c Determine the percent of steady-state 10 losses DO 113 j=Ojmax
pfluxcen(j)=(fluxcen(j)qlD) 100 pfluxo(j)=(fluxo(j)qlD)lOO pfluxi(j)=(fluxi(j)qlD)lOO
113 CONTINUE
c Determine where the heat transfer becomes 10 c based on a criticle percentage
flagl=O DO 114 j=O jmax
a=abs(pfluxcen(j)-lOOO) IF (j ne jmax) THEN
IF (a le oneDtol) THEN jstar=j
ENDIF ELSE
IF (a le oneDtol) THEN jstar=j
ELSE flagl=l
ENDIF ENDIF
98
114 CONTINUE
c Determine the edge loss by subtracting the 10 heat c transfer from the heat transfer in the 20 region c across the centerline
flag2=0 IF (flagl eq 0) THEN
q2D=00 DO 115 j=O jstar
q2D-q2D+fluxcen(j) 115 CONTINUE
qedgel=q2D-qlD ELSE
flag2=1 ENDIF
c 10 heat flux along metal skin under the seal into c the cabinet [Wm2J Fluxes for all metal nodes are c computed as well as an average flux The flux from c node (n3+l0) to node (n3+20) is given as qlDm(l) c and so on Assume the temperature of the metal skin c is the temperature of the node at that location
suml=OO sum2=00 DO 119 i=n3+1n3+n4-l
Qm(i)=laquokmdmb)dx)(T(i0)-T(i+10raquo qfluxm(i)=(kmdx)(T(iO)-T(i+lOraquo suml=suml+Qm(i) sum2=sum2+qfluxm(i)
119 CONTINUE pmaxdif=laquoQm(n3+n4-l)-Qm(n3+1raquoQm(n3+lraquo100 qedge2-qfluxm(cl)
cOutput
c Output nodal temperatures to separate file DO 120 j=Ojmax
write(ll) (T(ij)i=Oimax) 120 CONTINUE
c Output flux info to a different file write(10) INPUT PARAMETERS write(lO) write (10 ) Section Dimensions (mm) write(lO) Width sl1000 write (10 ) Length s21000 write(10) Depth blOOO write(10) Steel skin thickness dmlOOO write(lO) Plastic skin thickness dplOOO write(lO) write(10) Mesh Geometry write(10) dx dxlOOO write(lO) dy dylOOO write(lO) Number nodes in x-direction n1 write(lO) Number nodes in y-direction n2 write(lO) Number of steel skin nodes write(lO) (including corner 00) n5+l write(10) Steel nodes under the seal n3+1 ton3+n4 write(10) write(lO) Steel skin conductivity (Wm K) km write(lO) Foam insulation conductivity (Wm K) kins write(lO) Plastic skin conductivity (Wm K) kp write(lO) Outside h (Wm2 K) heffo write(lO) Inside h (Wm2 K) heffi
99
write(10) Outside Temp (C) To write(10) Inside Temp (C) Ti write(10) write (10 ) write(10) write(10) OUPUT PARAMETERS write (10 ) write(10) Number of iterations iter write(10) write(10) Heat Transfer for the Section write(10) OVerall Heat Transfer (W) Qin1 write(10) 10 Heat Flux Thru Wall (Wm2) q1D write (10 ) write(10) Heat Transfer Along Metal Skin Under Seal write(10) node to node qm[Wm2J Qm[WJ DO 135 i=n3+1n3+n4-1
write(10) i i+1 qfluxm(i) Qm(i) 135 CONTINUE
write (10 ) Maximum difference () abs (pmaxdif) write(10) IF (flag2 eq 1) THEN
write(10) The mesh does not extend far enough write(10) in the y-direction to reach 10 heat write(10) transfer for the specified tolerance write(10) ofoneDtol
ELSE write (10 ) Edge loss computed from qe=q2D-q1D qedge1 write (10 ) write(10) Edge loss computed directly from write(10) steel skin ~T at centerline qedge2
ENDIF write (10 ) write (10 ) write(10) Heat fluxes in thru the section write(10) along the centerline [Wm2J write (10 ) write(10) j flux 10 DO 136 j=Ojmax
write(10) j fluxcen(j) pfluxcen(j) 136 CONTINUE
PAUSE STOP END
C
SUBROUTINE sseqn (Trplusirminusirplusjrminusj i jimax jmax)
c This subroutine computes the temperature at node (ij) c given the temperatures of the surrounding nodes and c the resistances leading to these nodes
INTEGER ijimaxjmax REAL T(-1101-1101)rplusirminusirplusjrminusj REAL c1c2c3c4c5
c1=1rplusi c2=1rminusi c3=1rplusj c4=1rminusj c5=c1+c2+c3+c4
T(ij)=(1c5)(c1T(i+1j)+c2T(i-1j)+c3T(ij+1)+c4T(ij-1raquo
100
RETURN END
C
SUBROUTINE balance(TToTidxdyn3n4imaxjmaxQdifQpdif c Qin1Qin2r7r8r9r10r11b)
c This subroutine computes the steady-state heat balance c for the cross-section
INTEGER imaxjmaxijn3n4 REAL T(-1101-1101)TlToQin1Qin2dydx REAL r7r8r9r10r11b
c Compute the heat entering Qin1 [Wj Qin1=00 DO 10 jOjmax
Qin1=Qin1+(b(r7))(To-T(0j)) 10 CONTINUE
DO 20 i=0n3 Qin1=Qin1+(b(r8))(To-T(i0))
20 CONTINUE
c Compute the heat leaving Qin2 [Wj Qin2=00 DO 30 j=Ojmax
Qin2=Qin2+(b(r10))(T(imaxj)-Ti) 30 CONTINUE
DO 40 i=n3+n4+1imax IF (i le nS) then
Qin2=Qin2+(b(r9))(T(i0)-Ti) ELSE
Qin2=Qin2+(b(r11))(T(i0)-Ti) ENDIF
40 CONTINUE
c Compute the absolute difference in heat fluxes [Wj Qdif=abs(Qin2-Qin1)
c Compute the percent difference in the heat transfers [Wj Qpdif=(QdifQin1) 100
RETURN END
C
SUBROUTINE oneD (ToTiheffoheffikmkinskpdmdpslqlD)
c This subroutine compute the one-dimensional c heat flux through the section wall
INTEGER i REAL ToTiheffoheffikmkinskpdmdpsl REAL q1DReqdins
dins=sl-dm~dp
Req=(lheffo) + (dmkm) + (dinskins) +(dpkp)+(lheffi) q1D=(To-Ti)Req
RETURN END
101
F3 Fresh Food Wan Simulation Output
INPUT PARAMETERS
Section Dimensions (mm) Width 4500 Length 2000 Depth 1000 Steel skin thickness 6500 Plastic skin thickness 2500
Mesh Geometry dx 2250 dy 2500 Number nodes in x-direction 20 Number nodes in y-direction 80 Number of steel skin nodes (including corner 00) 11 Steel nodes under the seal 2 to 10
Steel skin conductivity (Wm K) 5400 Foam insulation conductivity (Wm K) 21000E-02 Plastic skin conductivity (Wm K) 1500 Outside h (Wm2 K) 6810 Inside h (Wm2 K) 6100 Outside Temp (C) 2100 Inside Temp (C) 4000
OUPUT PARAMETERS
Number of iterations 5318
10 Heat Flux Thru Wall (Wm2) 9132
Heat Transfer Along Metal Skin Under Seal node to node qm[Wm2] Qm[W]
2 3 1619 1092 3 4 1612 1081 4 5 1660 1019 5 6 1645 1010 6 1 1626 1051 1 8 1601 1041 8 9 1569 1020 9 10 1521 9922
Maximum difference () 9101
Edge loss computed directly from steel skin 1T at centerline 1645
Heat fluxes in thru the section along the centerline [Wm2]
j flux 10 0 4284 4691 1 2246 2459 2 3513 3841 3 4554 4981 4 5311 5881 5 6001 6512 6 6488 1104 1 6868 1520
102
10
20
30
40
50
60
70
8 7169 7850 9 7412 8117
7612 8335 11 7778 8517 12 7918 8670 13 8037 8800 14 8139 8912 15 8227 9008 16 8303 9092 17 8369 9164 18 8428 9228 19 8479 9285
8525 9334 21 8565 9379 22 8601 9418 23 8634 9454 24 8663 9486 25 8690 9515 26 8714 9542 27 8736 9566 28 8756 9588 29 8775 9609
8793 9628 31 8809 9645 32 8824 9662 33 8838 9677 34 8851 9692 35 8863 9705 36 8875 9718 37 8886 9730 38 8896 9742 39 8906 9752
8916 9763 41 8925 9772 42 8933 9782 43 8941 9791 44 8949 9799 45 8956 9807 46 8963 9815 47 8970 9822 48 8976 9829 49 8982 9836
8988 9842 51 8994 9848 52 8999 9854 53 9004 9859 54 9009 9864 55 9013 9869 56 9017 9874 57 9021 9878 58 9025 9883 59 9029 9887
9032 9890 61 9036 9894 62 9039 9897 63 9042 9901 64 9044 9903 65 9047 9906 66 9049 9909 67 9051 9911 68 9053 9913 69 9055 9915
9057 9917 71 9058 9919
103
72 9059 9920 73 9061 9921 74 9062 9922 75 9062 9923 76 9063 9924 77 9063 9924 78 9064 9925 79 9064 9925
j local Qwall [Wl
-1 3215 0 -45410E-02 1 -50708E-02 2 -40940E-02 3 -33836E-02 4 -27620E-02 5 -23180E-02 6 -1 9628E-02 7 -1 6076E-02 8 -1 4300E-02 9 -12524E-02 10 -10748E-02 11 -98601E-03 12 -89722E-03 13 -80842E-03 14 -71962E-03 15 -63081E-03 16 -63082E-03 17 -54202E-03 18 -54202E-03 19 -45322E-03 20 -45322E-03 21 -45322E-03 22 -45321E-03 23 -36442E-03 24 -36442E-03 25 -36442E-03 26 -27562E-03 27 -27561E-03 28 -27561E-03 29 -27561E-03 30 -27561E-03 31 -18682E-03 32 -18682E-03 33 -27561E-03 34 -18682E-03 35 -18682E-03 36 -18681E-03 37 -18682E-03 38 -98018E-04 39 -98018E-04 40 -98018E-04 41 -98018E-04 42 -98018E-04 43 -98018E-04 44 -98018E-04 45 -98018E-04 46 -98018E-04 47 -18682E-03 48 -98018E-04 49 -98018E-04 50 -98018E-04 51 -98018E-04 52 -98018E-04
104
53 -98018E-04 54 -92160E-05 55 -98018E-04 56 -98018E-04 57 -98018E-04 58 -98018E-04 59 -98018E-04 60 -92160E-05 61 -98018E-04 62 -92160E-05 63 -98018E-04 64 -98018E-04 65 -92160E-05 66 -98018E-04 67 -98018E-04 68 -92245E-05 69 -92245E-05 70 -98018E-04 71 -98018E-04 72 -98018E-04 73 -92160E-05 74 -92160E-05 75 -92160E-05 76 -92160E-05 77 -92160E-05 78 -92160E-05 79 -92160E-05
Qwallff [Wm21 = 1442 Qwallff [WI = 2775
Fresh Food Nodal Temperatures
x(mm) v(mm) 1125 3375 5625 7875 10125 12375 14625 16875 19125 21375
125 1761 1755 1748 1741 1734 1727 172 1713 1706 17 375 1768 1753 1738 1723 1707 169 1671 165 1624 1589 625 1775 1752 173 1706 1682 1656 1626 1593 1552 15 875 1781 1751 1722 1691 1659 1625 1587 1544 1494 1434
1125 -1787 1751 1715 1678 1639 1598 1553 1504 1448 1384 1375 1792 1751 1709 1667 1622 1576 1526 1471 1412 1346 1625 1798 1752 1705 1658 1609 1557 1503 1446 1384 ll17 1875 1803 1753 1702 165 1597 1543 1485 1425 1362 1294 2125 1808 1754 17 1645 1589 1531 1471 1409 1344 1276 2375 1813 1756 1699 1641 1582 1522 146 1396 133 1262 2625 1817 1758 1698 1638 1577 1515 1451 1386 132 1251 2875 1822 176 1698 1636 1573 151 1445 1379 1311 1242 3125 1826 1762 1699 1635 1571 1506 144 1373 1304 1235 3375 183 1765 17 1635 1569 1503 1436 1368 1299 1229 3625 1834 1768 1701 1635 1568 1501 1433 1364 1295 1225 3875 1837 177 1703 1635 1568 15 1431 1362 1292 1222 4125 1841 1773 1705 1636 1568 1499 143 136 129 1219 4375 1845 1776 1707 1638 1568 1499 1429 1359 1289 1218 4625 1848 1778 1709 1639 1569 1499 1429 1358 1288 1216 4875 1851 1781 1711 164 157 15 1429 1358 1287 1216 5125 1854 1784 1713 1642 1571 15 1429 1358 1287 1215 5375 1857 1786 1715 1644 1573 1501 143 1358 1287 1215 5625 186 1789 1717 1646 1574 1502 1431 1359 1287 1215
105
5875 1863 1791 1719 1647 1576 1504 1432 136 1288 1215 6125 1866 1794 1721 1649 1577 1505 1433 136 1288 1216 6375 1868 1796 1723 1651 1579 1506 1434 1361 1289 1216 6625 1871 1798 1725 1653 158 1508 1435 1362 129 1217 6875 1873 18 1727 1655 1582 1509 1436 1363 1291 1218 7125 1876 1803 1729 1656 1583 151 1437 1364 1291 1218 7375 1878 1805 1731 1658 1585 1512 1439 1366 1292 1219 7625 188 1807 1733 166 1587 1513 144 1367 1293 122 7875 1882 1809 1735 1661 1588 1515 1441 1368 1294 1221 8125 1884 181 1737 1663 159 1516 1442 1369 1295 1222 8375 1886 1812 1738 1665 1591 1517 1444 137 1296 1223 8625 1888 1814 174 1666 1592 1519 1445 1371 1297 1224 8875 189 1816 1742 1668 1594 152 1446 1372 1298 1225 9125 1892 1817 1743 1669 1595 1521 1447 1373 1299 1225 9375 1893 1819 1745 1671 1596 1522 1448 1374 13 1226 9625 1895 182 1746 1672 1598 1524 1449 1375 1301 1227 9875 1896 1822 1748 1673 1599 1525 145 1376 1302 1228 10125 1898 1823 1749 1674 16 1526 1451 1377 1303 1229 10375 1899 1825 175 1676 1601 1527 1452 1378 1304 123 10625 1901 1826 1751 1677 1602 1528 1453 1379 1305 123 10875 1902 1827 1753 1678 1603 1529 1454 138 1305 1231 11125 1903 1828 1754 1679 1604 153 1455 1381 1306 1232 11375 1904 183 1755 168 1605 1531 1456 1381 1307 1232 11625 1906 1831 1756 1681 1606 1532 1457 1382 1308 1233 11875 1907 1832 1757 1682 1607 1532 1458 1383 1308 1234 12125 1908 1833 1758 1683 1608 1533 1458 1384 1309 1234 12375 1909 1834 1759 1684 1609 1534 1459 1384 131 1235 12625 191 1835 176 1685 161 1535 146 1385 131 1235 12875 1911 1836 1761 1686 1611 1536 1461 1386 1311 1236 13125 1912 1837 1761 1686 1611 1536 1461 1386 1311 1236 13375 1913 1837 1762 1687 1612 1537 1462 1387 1312 1237 13625 1913 1838 1763 1688 1613 1538 1462 1387 1312 1237 13875 1914 1839 1764 1688 1613 1538 1463 1388 1313 1238 14125 1915 184 1764 1689 1614 1539 1464 1388 1313 1238 14375 1916 184 1765 169 1614 1539 1464 1389 1314 1239 14625 1916 1841 1766 169 1615 154 1465 1389 1314 1239 14875 1917 1842 1766 1691 1616 154 1465 139 1315 1239 15125 1918 1842 1767 1691 1616 1541 1465 139 1315 124 15375 1918 1843 1767 1692 1616 1541 1466 1391 1315 124 15625 1919 1843 1768 1692 1617 1542 1466 1391 1316 124 15875 1919 1844 1768 1693 1617 1542 1467 1391 1316 1241 16125 192 1844 1769 1693 1618 1542 1467 1392 1316 1241 16375 192 1844 1769 1694 1618 1543 1467 1392 1317 1241 16625 192 1845 1769 1694 1618 1543 1468 1392 1317 1241 16875 1921 1845 177 1694 1619 1543 1468 1392 1317 1242 17125 1921 1846 177 1694 1619 1544 1468 1393 1317 1242 17375 1921 1846 177 1695 1619 1544 1468 1393 1317 1242 17625 1922 1846 1771 1695 1619 1544 1469 1393 1318 1242 17875 1922 1846 1771 1695 162 1544 1469 1393 1318 1242 18125 1922 1847 1771 1695 162 1544 1469 1393 1318 1243 18375 1922 1847 1771 1696 162 1545 1469 1394 1318 1243 18625 1923 1847 1771 1696 162 1545 1469 1394 1318 1243 18875 1923 1847 1771 1696 162 1545 1469 1394 1318 1243 19125 1923 1847 1772 1696 162 1545 1469 1394 1318 1243 19375 1923 1847 1772 1696 162 1545 1469 1394 1318 1243 19625 1923 1847 1772 1696 1621 1545 1469 1394 1318 1243 19875 1923 1847 1772 1696 1621 1545 1469 1394 1318 1243
106
x(mm) y(mm) 23625 25875 28125 30375 32625 34875 37125 39375 41625 43875
125 1694 1662 1287 1033 8577 7336 6444 5795 5324 4995 375 1536 144 125 1068 9163 7946 6974 6189 5532 4944 625 1431 1334 1203 1066 9379 8252 7275 6423 5657 4935 875 136 127 1164 1051 9408 8374 7423 6548 573 4941
1125 131 1226 1132 1034 9353 8394 7477 6605 5766 4948 1375 1273 1193 1107 1017 9262 836 7478 6618 5779 4952 1625 1245 1168 1086 1002 9162 8302 7449 6607 5776 4951 1875 1223 1148 1069 9886 9064 8236 7408 6583 5764 4948 2125 1205 1132 1055 977 8974 8169 7362 6554 5747 4941 2375 1191 1119 1044 9671 8893 8107 7316 6522 5728 4933 2625 118 1108 1034 9588 8824 8051 7273 6492 5709 4925 2875 1172 11 1026 9518 8764 8002 7235 6464 5691 4916 3125 1164 1093 102 946 8713 796 7201 6439 5674 4908 3375 1159 1087 1015 9412 8671 7924 7172 6417 566 49 3625 1154 1083 101 9373 8636 7894 7148 6399 5647 4894 3875 1151 1079 1007 9341 8608 7869 7128 6383 5636 4888 4125 1148 1077 1004 9316 8585 7849 7111 637 5627 4883 4375 1146 1074 1002 9296 8566 7833 7097 6359 5619 4879 4625 1145 1073 1001 9281 8552 7821 7087 6351 5613 4875 4875 1144 1072 9995 927 8541 7811 7078 6344 5609 4872 5125 1143 1071 9987 9261 8533 7803 7072 6339 5605 487 5375 1143 1071 9982 9256 8528 7798 7067 6335 5602 4868 5625 1143 107 9979 9253 8524 7795 7064 6332 56 4867 5875 1143 107 9978 9251 8522 7793 7062 6331 5599 4866 6125 1143 1071 9979 9251 8522 7792 7061 633 5598 4866 6375 1144 1071 9981 9252 8523 7792 7061 633 5598 4865 6625 1144 1071 9984 9255 8524 7793 7062 633 5598 4865 6875 1145 1072 9988 9258 8526 7795 7063 6331 5598 4865 7125 1145 1072 9993 9261 8529 7797 7065 6332 5599 4866 7375 1146 1073 9998 9265 8533 78 7067 6333 56 4866 7625 1147 1074 10 927 8536 7803 7069 6335 5601 4867 7875 1148 1074 1001 9275 854 7806 7072 6337 5602 4867 8125 1148 1075 1001 928 8545 7809 7074 6339 5603 4868 8375 1149 1076 1002 9285 8549 7813 7077 6341 5605 4869 8625 115 1076 1003 929 8553 7817 708 6343 5606 4869 8875 1151 1077 1003 9295 8558 782 7083 6345 5608 487 9125 1152 1078 1004 93 8562 7824 7086 6347 5609 4871 9375 1152 1078 1004 9306 8567 7828 7089 635 5611 4872 9625 1153 1079 1005 9311 8571 7831 7092 6352 5612 4873 9875 1154 108 1006 9316 8575 7835 7094 6354 5614 4873 10125 1155 108 1006 9321 858 7838 7097 6356 5615 4874 10375 1155 1081 1007 9326 8584 7842 71 6358 5617 4875 10625 1156 1082 1007 933 8588 7845 7103 636 5618 4876 10875 1157 1082 1008 9335 8592 7848 7105 6362 5619 4876 11125 1157 1083 1008 9339 8596 7852 7108 6364 5621 4877 11375 1158 1083 1009 9344 8599 7855 711 6366 5622 4878 11625 1158 1084 1009 9348 8603 7858 7113 6368 5623 4879 11875 1159 1084 101 9352 8606 7861 7115 637 5625 4middot879 12125 116 1085 101 9356 861 7864 7117 6372 5626 488 12375 116 1085 1011 936 8613 7866 712 6373 5627 488 12625 1161 1086 1011 9363 8616 7869 7122 6375 5628 4881 12875 1161 1086 1011 9367 8619 7871 7124 6376 5629 4882 13125 1162 1087 1012 937 8622 7874 7126 6378 563 4882 13375 1162 1087 1012 9373 8625 7876 7128 6379 5631 4883 13625 1162 1087 1013 9376 8627 7878 7129 6381 5632 4883
107
13875 1163 1088 1013 9379 863 788 7131 6382 5633 4884 14125 1163 1088 1013 9382 8632 7882 7133 6383 5634 4884 14375 1164 1089 1013 9384 8634 7884 7134 6384 5634 4885 14625 1164 1089 1014 9387 8636 7886 7136 6385 5635 4885 14875 1164 1089 1014 9389 8638 7888 7137 6386 5636 4885 15125 1165 1089 1014 9392 864 7889 7138 6387 5637 4886 15375 1165 109 1015 9394 8642 7891 714 6388 5637 4886 15625 1165 109 1015 9396 8644 7892 7141 6389 5638 4886 15875 1165 109 1015 9398 8646 7894 7142 639 5638 4887 16125 1166 109 1015 9399 8647 7895 7143 6391 5639 4887 16375 1166 1091 1015 9401 8649 7896 7144 6392 5639 4887 16625 1166 1091 1016 9403 865 7897 7145 6392 564 4888 16875 1166 1091 1016 9404 8651 7898 7146 6393 564 4888 17125 1167 1091 1016 9405 8652 7899 7146 6394 5641 4888 17375 1167 1091 1016 9406 8653 79 7147 6394 5641 4888 17625 1167 1091 1016 9407 8654 7901 7148 6395 5641 4888 17875 1167 1092 1016 9408 8655 7902 7148 6395 5642 4889 18125 1167 1092 1016 9409 8656 7902 7149 6395 5642 4889 18375 1167 1092 1016 941 8656 7903 7149 6396 5642 4889 18625 1167 1092 1016 9411 8657 7903 715 6396 5642 4889 18875 1167 1092 1017 9411 8657 7904 715 6396 5643 4889 19125 1167 1092 1017 9412 8658 7904 715 6396 5643 4889 19375 1167 1092 1017 9412 8658 7904 715 6397 5643 4889 19625 1167 1092 1017 9412 8658 7904 715 6397 5643 4889 19875 1168 1092 1017 9412 8658 7904 715 6397 5643 4889
F4 Freezer Wall Simulation Output
INPUT PARAMETERS
Section Dimensions (mm) Width 5600 Length 2000 Depth 1000 Steel skin thickness 6500 Plastic skin thickness 2500
Mesh Geometry dx 2800 dy 2500 Number nodes in x-direction 20 Number nodes in y-direction 80 Number of steel skin nodes (including corner 00) 9 Steel nodes under the seal 2 to 8
Steel skin conductivity (Wm K) 5400 Foam insulation conductivity (Wm K) 27000E-02 Plastic skin conductivity (Wm K) 1500 Outside h (Wm2 K) 6870 Inside h (Wm2 K) 6410 Outside Temp (C) 2100 Inside Temp (C) -1000
OUPUT PARAMETERS
108
Number of iterations 5409
Heat Transfer for the Section OVerall Heat Transfer (WI 4518 10 Heat Flux Thru Wall (Wm21 1362
Heat Transfer Along Metal Skin Under Seal node to node
2 3 3 4 4 5 5 6 6 7 7 8
Maximum difference
qm[Wm2) Om(W) 3026 1967 3008 1955 2981 1938 2944 1914 2892 1880 2820 1833
(1 6799
Edge loss computed from qe=q20-q1D 1760
Edge loss compusteel skin AT
ted directly from at centerline 2981
Heat fluxes in thru the section along the centerline [Wm2)
j flux UO 0 7762 5698 1 3711 2724 2 5678 41 68 3 7275 5341 4 8508 6246 5 9437 6927 6 1013 7438 7 1066 7823 8 1106 8117 9 1137 8347 10 1162 8529 11 1182 8678 12 1199 8801 13 1213 8904 14 1225 8992 15 1235 9068 16 1244 9135 17 1252 9193 18 1259 9245 19 1266 9291 20 1271 9333 21 1276 9370 22 1281 9405 23 1285 9436 24 1289 9464 25 1293 9491 26 1296 9515 27 1299 9538 28 1302 9559 29 1305 9578 30 1307 9596 31 1310 9614 32 1312 9630 33 1314 9645 34 1316 9659 35 1318 9673 36 1319 9685 37 1321 9697
109
38 1323 9709 39 1324 9720 40 1325 9730 41 1327 9740 42 1328 9749 43 1329 9758 44 1330 9767 45 1332 9775 46 1333 9783 47 1334 97bull 90 48 1335 9797 49 1336 9804 50 1336 9810 51 1337 9816 52 1338 9822 53 1339 9828 54 1340 9833 55 1340 9838 56 1341 9843 57 1341 9847 58 1342 9852 59 1343 9856 60 1343 9859 61 1344 9863 62 1344 9866 63 1344 9870 64 1345 9873 65 1345 9875 66 1346 9878 67 1346 9880 68 1346 9882 69 1347 9884 70 1347 9886 71 1347 9888
72 1347 9889 73 1347 9891 74 1347 9892 75 1348 9893 76 1348 9893 77 1348 9894 78 1348 9894 79 1348 9894
j local Qwall [WI
-1 3067 0 -36774E-02 1 -40214E-02 2 -32314E-02 3 -25994E-02 4 -20859E-02 5 -16909E-02 6 -14144E-02 7 -12169E-02 8 -10589E-02 9 -90092E-03 10 -78242E-03 11 -70342E-03 12 -66392E-03 13 -58492E-03 14 -54542E-03 15 -50592E-03 16 -46642E-03 17 -42692E-03 18 -42692E-03
110
19 -38742E-03 20 -34792E-03 21 -30842E-03 22 -30842E-03 23 -30842E-03 24 -26892E-03 25 -26892E-03 26 -22942E-03 27 -22942E-03 28 -22942E-03 29 -22942E-03 30 -18992E-03 31 -1 8992E-03 32 -18992E-03 33 -18992E-03 34 -1 8992E-03 35 -1 5042E-03 36 -1 8992E-03 37 -15042E-03 38 -1 5042E-03 39 -11092E-03 40 -11092E-03 41 -11092E-03 42 -11092E-03 43 -11092E-03 44 -11092E-03 45 -11092E-03 46 -11092E-03 47 -71417E-04 48 -11092E-03 49 -71421E-04 50 -11092E-03 51 -71417E-04 52 -11092E-03 53 -71417E-04 54 -71421E-04 55 -71421E-04 56 -71417E-04 57 -31916E-04 58 -31920E-04 59 -31916E-04 60 -31916E-04 61 -71417E-04 62 -11421E-04 63 -71421E-04 64 -31920E-04 65 -31920E-04 66 -71417E-04 67 -31916E-04 68 -71417E-04 69 -31920E-04 70 -71421E-04 71 -31920E-04 72 -31920E-04 73 -71417E-04 74 -31916E-04 75 -31916E-04 76 -31916E-04 77 -31916E-04 78 -71417E-04 79 -71417E-04
Qwallfz [Wm2J = 2895 Qwallfz [WJ = 2721
111
Freezer Wan Nodal Temperatures
x(mm) y1mm 14 42 70 98 126 154 182 210 238 266
125 1507 1492 1477 1461 1445 143 1415 14 1385 1338 375 1519 1489 1458 1426 1392 1353 1307 1247 1154 972 625 1531 1486 1441 1393 1341 1282 1212 1121 9925 7989 875 1542 1484 1425 1363 1296 1221 1132 1023 8837 7014
1125 1553 1483 1412 1338 1258 117 1069 9508 809 6396 1375 1563 1483 1401 1317 1227 1129 102 8969 7563 5974 1625 1572 1483 1393 13 1202 1097 9824 8568 7184 5673 1875 1582 1485 1387 1287 1182 1072 9537 8269 6906 5452 2125 1591 1488 1384 1277 1167 1053 9321 8046 67 5288 2375 1599 1491 1382 1271 1157 1039 916 7881 6547 5164 2625 1608 1495 1381 1266 1149 1028 9041 7758 6433 5071 2875 1616 1499 1382 1264 1144 1021 8955 7668 6349 5002 3125 1623 1504 1384 1263 114 1016 8895 7604 6288 495 3375 1631 1509 1386 1263 1139 1013 8854 7559 6245 4913 3625 1638 1514 1389 1264 1138 1011 8829 753 6216 4888 3875 1645 1519 1393 1266 1139 1011 8816 7513 6198 4872 4125 1652 1524 1396 1269 114 1011 8813 7505 6188 4863 4375 1658 1529 14 1271 1142 1012 8817 7505 6185 486 4625 1664 1534 1405 1275 1144 1014 8826 751 6188 4861 4875 167 1539 1409 1278 1147 1016 884 752 6195 4867 5125 1676 1544 1413 1281 115 1018 8858 7533 6206 4875 5375 1682 1549 1417 1285 1153 102 8877 755 6219 4886 5625 1687 1554 1421 1289 1156 1023 8899 7568 6235 4899 5875 1692 1559 1425 1292 1159 1026 8923 7588 6252 4914 6125 1698 1563 143 1296 1162 1028 8947 7609 627 493 6375 1702 1568 1434 1299 1165 1031 8972 763 6289 4946 6625 1707 1572 1438 1303 1169 1034 8997 7653 6308 4964 6875 1712 1576 1441 1306 1172 1037 9022 7675 6329 4982 7125 1716 158 1445 131 1175 104 9048 7698 6349 5 7375 172 1584 1449 1313 1178 1043 9073 7721 6369 5018 7625 1724 1588 1452 1317 1181 1045 9098 7744 639 5036 7875 1728 1592 1456 132 1184 1048 9123 7766 641 5054 8125 1732 1595 1459 1323 1187 1051 9147 7788 643 5072 8375 1736 1599 1462 1326 1189 1053 917 781 645 509 8625 1739 1602 1465 1329 1192 1056 9194 7831 6469 5108 8875 1743 1605 1468 1332 1195 1058 9216 7852 6488 5125 9125 1746 1609 1471 1334 1197 1061 9238 7872 6507 5142 9375 1749 1612 1474 1337 12 1063 926 7892 6525 5158 9625 1752 1615 1477 134 1202 1065 9281 7911 6542 5174 9875 1755 1617 148 1342 1205 1067 9301 793 656 519 10125 1758 162 1482 1344 1207 1069 9321 7948 6576 5205 10375 1761 1623 1485 1347 1209 1071 934 7966 6593 522 10625 1763 1625 1487 1349 1211 1073 9358 7983 6608 5234 10875 1766 1627 1489 1351 1213 1075 9376 7999 6623 5248 11125 1768 163 1491 1353 1215 1077 9393 8015 6638 5262 11375 1771 1632 1494 1355 1217 1079 941 8031 6652 5275 11625 1773 1634 1496 1357 1219 1081 9426 8045 6666 5287 11875 1775 1636 1498 1359 1221 1082 9441 806 6679 53 12125 1777 1638 1499 1361 1222 1084 9456 8073 6692 5311 12375 1779 164 1501 1362 1224 1085 947 8087 6704 5322 12625 1781 1642 1503 1364 1225 1087 9483 8099 6716 5333 12875 1783 1644 1505 1366 1227 1088 9496 8111 6727 5344
112
13125 1784 1645 1506 1367 1228 109 9509 8123 6738 5353 13375 1786 1647 1508 1369 123 1091 9521 8134 6748 5363 13625 1788 1648 1509 137 1231 1092 9532 8145 6758 5372 13875 1789 165 151 1371 1232 1093 9543 8155 6768 5381 14125 1791 1651 1512 1373 1233 1094 9554 8165 6777 5389 14375 1792 1652 1513 1374 1235 1095 9564 8174 6785 5397 14625 1793 1654 1514 1375 1236 1096 9573 8183 6793 5404 14875 1794 1655 1515 1376 1237 1097 9582 8191 6801 5412 15125 1796 1656 1516 1377 1238 1098 959 8199 6808 5418 15375 1797 1657 1517 1378 1238 1099 9598 8206 6815 5425 15625 1798 1658 1518 1379 1239 11 9606 8213 6822 5431 15875 1799 1659 1519 138 124 1101 9613 822 6828 5436 16125 18 166 152 138 1241 1101 9619 8226 6834 5442 16375 18 1661 1521 1381 1242 1102 9626 8232 6839 5446 16625 1801 1661 1521 1382 1242 1103 9631 8237 6844 5451 16875 1802 1662 1522 1382 1243 1103 9637 8242 6848 5455 17125 1803 1663 1523 1383 1243 1104 9642 8247 6853 5459 17375 1803 1663 1523 1384 1244 1104 9646 8251 6857 5463 17625 1804 1664 1524 1384 1244 1105 965 8255 686 5466 17875 1804 1664 1524 1384 1245 1105 9654 8258 6863 5469 18125 1805 1665 1525 1385 1245 1105 9657 8261 6866 5471 18375 1805 1665 1525 1385 1245 1106 966 8264 6869 5474 18625 1805 1665 1525 1385 1246 1106 9662 8266 6871 5476 18875 1806 1666 1526 1386 1246 1106 9664 8268 6872 5477 19125 1806 1666 1526 1386 1246 1106 9666 827 6874 5479 19375 1806 1666 1526 1386 1246 1106 9667 8271 6875 548 19625 1806 1666 1526 1386 1246 1107 9668 8271 6876 548 19875 1806 1666 1526 1386 1246 1107 9668 8272 6876 5481
x(mm) v(mm) 294 322 350 378 406 434 462 490 518 546
125 549 054 -27 -5 -624 -727 -8 -85 -89 -92 375 548 171 -12 -338 -5 -624 -719 -795 -858 -914 625 51 22 -032 -24 -408 -543 -654 -748 -83 -907 875 474 238 0182 -175 -34 -482 -603 -71 -807 -898
1125 445 243 048 -132 -293 -436 -564 -68 -787 -89 1375 423 243 0653 -103 -259 -402 -534 -656 -772 -883 1625 406 24 0752 -084 -236 -378 -511 -638 -759 -877 1875 393 237 0808 -071 -219 -36 -495 -624 -749 -871 2125 382 233 0837 -063 -208 -348 -483 -614 -741 -867 2375 374 23 085 -058 -2 -339 -474 -606 -735 -863 2625 368 227 0855 -055 -195 -332 -467 -6 -731 -86 2875 363 225 0855 -053 -191 -328 -462 -596 -728 -858 3125 36 223 0853 -052 -189 -324 -459 -593 -725 -856 3375 357 221 0851 -051 -187 -322 -457 -59 -723 -855 3625 355 22 0849 -05 -186 -32 -455 -588 -722 -854 3875 354 219 0849 -049 -185 -319 -453 -587 -72 -853 4125 353 219 0849 -049 -184 -318 -452 -586 -72 -853 4375 353 219 0852 -049 -183 -317 -451 -585 -719 -852 4625 353 219 0855 -048 -183 -317 -451 -584 -718 middot852 4875 353 22 0861 -047 -182 -316 -45 -584 -718 -852 5125 354 22 0867 -047 -181 -315 -449 -584 -717 -851 5375 355 221 0875 -046 -181 -315 -449 -583 -717 -851 5625 356 222 0884 -045 -18 -314 -448 -582 -717 -851 5875 358 223 0894 -044 -179 -313 -448 -582 -716 -851 6125 359 225 0904 -043 -178 -313 -447 -582 -716 -851 6375 36 226 0915 -043 -177 -312 -447 -581 -716 -85
113
6625 362 227 0927 -042 -177 -311 -446 -581 -716 -85 6875 363 229 0939 -04 -176 -311 -445 -58 -715 -85 7125 365 23 0951 -039 -175 -31 -445 -58 -715 -85 7375 367 232 0964 -038 -174 -309 -444 -579 -715 -85 7625 368 233 0976 -037 -173 -308 -444 -579 -714 -85 7875 37 234 0989 -036 -172 -308 -443 -578 -714 -849 8125 371 236 1 -035 -171 -307 -442 -578 -714 -849 8375 373 237 101 -034 -17 -306 -442 -578 -713 -849 8625 375 239 103 -033 -169 -305 -441 -577 -713 -849 8875 376 24 104 -032 -168 -305 -441 -577 -713 -849 9125 378 241 105 -031 -168 -304 -44 -576 -712 -849 9375 379 243 106 -03 -167 -303 -439 -576 -712 -848 9625 381 244 107 -029 -166 -302 -439 -575 -712 -848 9875 382 245 109 -028 -165 -302 -438 -575 -712 -848 10125 384 246 11 -027 -164 -301 -438 -574 -711 -848 10375 385 248 111 -026 -163 -3 -437 -574 -711 -848 10625 386 249 112 -025 -163 -3 -437 -574 -711 -848 10875 387 25 113 -024 -162 -299 -436 -573 -711shy -848 11125 389 251 114 -023 -161 -298 -436 -573 -71 -848 11375 39 252 115 -022 -16 -298 -435 -573 -71 -847 11625 391 253 115 -022 -16 -297 -435 -572 -71 -847 11875 392 254 116 -021 -159 -297 -434 -572 -709 -847 12125 393 255 117 -02 -158 -296 -434 -572 -709 -847 12375 394 256 118 -019 -158 -296 -434 -571 -709 -847 12625 395 257 119 -019 -157 -295 -433 -571 -709 -847 12875 396 258 12 -018 -157 -295 -433 -571 -709 -847 13125 397 259 12 -017 -156 -294 -432 -57 -709 -847 13375 398 259 121 -017 -155 -294 -432 -57 -708 -847 13625 399 26 122 -016 -155 -293 -432 -57 -708 -846 13875 399 261 122 -016 -154 -293 -431 -57 -708 -846 14125 4 262 123 -015 -154 -292 -431 -569 -708 -846 14375 401 262 124 -015 -154 -292 -431 -569 -708 -846 14625 402 263 124 -014 -153 -292 -43 -569 -707 -846 14875 402 263 125 -014 -153 -291 -43 -569 -707 -846 15125 403 264 125 -013 -152 -291 -43 -569 -707 -846 15375 403 264 126 -013 -152 -291 -43 -568 -707 -846 15625 404 265 126 -012 -152 -291 -429 -568 -707 -846 15875 405 265 126 -012 -151 -29 -429 -568 -707 -846 16125 405 266 127 -012 -151 -29 -429 -568 -707 -846 16375 405 266 127 -011 -151 -29 -429 -568 -707 -846 16625 406 267 128 -011 -151 -29 -429 -568 -707 -846 16875 406 267 128 -011 -15 -289 -428 -568 -707 -845 17125 407 267 128 -01 -15 -289 -428 -567 -706 -845 17375 407 268 128 -01 -15 -289 -428 -567 -706 -845 17625 407 268 129 -01 -15 -289 -428 -567 -706 -845 17875 407 268 129 -01 -15 -289 -428 -567 -706 -845 18125 408 268 129 -01 -15 -289 -428 -567 -706 -845 18375 408 269 129 -01 -149 -289 -428 -567 -706 -845 18625 408 269 129 -001 -149 -288 -428 -567 -706 -845 18875 408 269 129 -001 -149 -288 -428 -567 -706 -845 19125 408 269 13 -001 -149 -288 -428 -567 -706 -845 19375 409 269 13 -001 -149 -288 -428 -567 -706 -845 19625 409 269 13 -001 -149 -288 -428 -567 -706 -845 19875 409 269 13 -001 -15 -288 -428 -567 -706 -845
114
FS Fresh Food Wan Simulation Output Including Anti-sweat Condenser Tube
INPUT PARAMETERS
Section Dimensions (mm) Hidth 4500 Length 2000 Depth 2960 Steel skin thickness 6500 Plastic skin thickness 2500
Mesh Geometry dx 2250 dy 2500 Number nodes in x-direction 20 Number nodes in y-direction 80 Number of steel skin nodes (including corner 00) 11 Steel nodes under the seal 2 to 10 Tube located at node 6
Steel skin conductivity (Him K) 5400 Foam insulation conductivity (Him K) 27000E-02 Plastic skin conductivity (Him K) 1500 Outside h (Hm2 K) 6870 Inside h (Hm2 K) 6700 Outside Temp (C) 2100 Inside Temp (C) 4000
OUPUT PARAMETERS
Number of iterations 602
10 Heat Flux Thru Hall (Hm2) 9132
Heat Transfer Along Metal Skin Under Seal node to node qm[Hm21 Qm[HI
2 3 -15052E+04 -2896 3 4 -15125E+04 -2910 4 5 -15198E+04 -2924 5 6 -15274E+04 -2939 6 7 3996 7688 7 8 3898 7500 8 9 3790 7292 9 10 3662 7045
Maximum difference () 1243
j qleft [HI qright [HI -1 -2957 7832 0 -92065E-02 -38838E-02 1 -77348E-02 -48044E-02 2 -51596E-02 -30284E-02 3 -32948E-02 -15188E-02 4 -1 9628E-02 -54201E-03 5 -98600E-03 16837E-03 6 -36442E-03 70ll8E-03 7 79586E-04 96757E-03 8 43478E-03 11452E-02 9 70118E-03 12340E-02 10 87877E-03 12340E-02
115
11 87879E-03 13228E-02 12 10564E-02 12340E-02 13 10564E-02 11452E-02 14 96759E-03 11452E-02 15 87877E-03 10564E-02 16 87879E-03 87877E-03 17 78999E-03 87877E-03 18 61238E-03 78999E-03 19 61240E-03 61237E-03 20 52359E-03 52358E-03 21 34598E-03 34598E-03 22 25719E-03 25717E-03 23 16838E-03 16839E-03 24 79586E-04 25 -98018E-04 26 -18681E-03 27 -27561E-03 28 -36442E-03 29 -54202E-03 30 -54202E-03 31 -7 1962E-03 32 -80842E-03 33 -8 9721E-03 34 -98602E-03 35 -10748E-02 36 -11636E-02 37 -12524E-02 38 -1 3412E-02 39 -1 4300E-02 40 -15188E-02 41 -1 5188E-02 42 -1 6076E-02 43 -16964E-02 44 -17852E-02 45 -1 7852E-02 46 -1 8740E-02 47 -19628E-02 48 -19628E-02 49 -19628E-02 50 -20516E-02 51 -21404E-02 52 -22292E-02 53 -22292E-02 54 -23180E-02 55 -23180E-02 56 -23180E-02 57 -24068E-02
79578E-04 -98018E-04 -1 8682E-03 -27561E-03 -45322E-03 -54202E-03 -71962E-03 -71962E-03 -8 9722E-03 -8 9722E-03 -10748E-02 -11636E-02 -12524E-02 -13412E-02 -14300E-02 -1 5188E-02 -16076E-02 -16964E-02 -16964E-02 -17852E-02 -18740E-02 -19628E-02 -20516E-02 -20516E-02 -21404E-02 -22292E-02 -22470E-02 -22381E-02 -22647E-02 -23358E-02 -23447E-02 -23802E-02 -24512E-02 -24690E-02
58 -23979E-02 -25223E-02 59 -24423E-02 60 -24246E-02 61 -24423E-02 62 -24779E-02 63 -25400E-02 64 -25400E-02 65 -25667E-02 66 -26199E-02 67 -26022E-02 68 -26111E-02 69 -26377E-02 70 -26022E-02 71 -26732E-02 72 -26821E-02 73 -26199E-02 74 -26643E-02
-25489E-02 -25755E-02 -25933E-02 -2 6199E-02 -26466E-02 -26643E-02 -26821E-02 -26910E-02 -27087E-02 -27265E-02 -27354E-02 -27443E-02 -27531E-02 -27620E-02 -27620E-02 -27709E-02
116
75 -26377E-02 -27709E-02 76 -26377E-02 -27709E-02 77 -26555E-02 -27709E-02 78 -26910E-02 -27620E-02 79 -26555E-02 -27620E-02
Qleft [ii] -3079 Qright [ii] 6756 Percent entering cabinet 1800
Fresh Food Nodal Temperatures (Condenser Tube)
x(mm) y(mm) 1125 3375 5625 7875 10125 12375 14625 16875 19125 21375
19875 126 1206 1154 1104 1055 1007 9608 9158 872 8294 19625 1259 1205 1153 1103 1054 1006 9602 9152 8715 8289 19375 1259 1205 1153 1102 1053 1006 9598 9149 8711 8285 19125 1259 1205 1153 1102 1053 1006 9596 9147 871 8284 18875 1259 1205 1153 1102 1053 1006 9596 9147 871 8284 18625 1259 1205 1153 1103 1054 1006 9599 915 8712 8286 18375 126 1206 1154 1103 1054 1007 9604 9154 8716 829 18125 1261 1207 1155 1104 1055 1007 9611 9161 8722 8295 17875 1263 1209 1156 1105 1056 1008 962 9169 873 8302 17625 1264 121 1158 1107 1058 101 9632 918 874 8311 17375 1266 1212 116 1109 1059 1011 9646 9193 8752 8322 17125 1269 1215 1162 1111 1061 1013 9663 9209 8766 8335 16875 1272 1217 1164 1113 1063 1015 9682 9226 8783 835 16625 1275 122 1167 1116 1066 1017 9704 9246 8801 8367 16375 1279 1224 117 1119 1069 102 9728 9269 8822 8386 16125 1282 1227 1174 1122 1072 1023 9755 9294 8845 8407 15875 1287 1231 1178 1126 1075 1026 9785 9322 887 843 15625 1292 1236 1182 113 1079 103 9818 9352 8898 8456 15375 1297 1241 1187 1134 1083 1034 9854 9385 8929 8484 15125 1302 1246 1192 1139 1088 1038 9892 9421 8962 8514 14875 1308 1252 1197 1144 1092 1042 9934 946 8998 8547 14625 1315 1258 1203 1149 1097 1047 9979 9502 9037 8583 14375 1322 1265 1209 1155 1103 1052 1003 9547 9078 8621 14125 1329 1272 1216 1162 1109 1058 1008 9595 9123 8662 13875 1337 1279 1223 1168 1115 1064 1014 9647 9171 8706 13625 1346 1287 1231 1176 1122 107 102 9703 9222 8753 13375 1355 1296 1239 1183 1129 1077 1026 9762 9277 8803 13125 1364 1305 1247 1191 1137 1084 1033 9824 9335 8856 12875 1374 1314 1256 12 1145 1092 104 9891 9396 8913 12625 1385 1325 1266 1209 1154 11 1047 9962 9462 8973 12375 1396 1335 1276 1219 1163 1109 1055 1004 9531 9037 12125 1408 1347 1287 1229 1173 1118 1064 1012 9605 9105 11875 1421 1359 1299 124 1183 1127 1073 102 9683 9176 11625 1434 1371 1311 1251 1194 1137 1082 1029 9765 9252 11375 1448 1385 1323 1263 1205 1148 1092 1038 9851 9332 11125 1462 1399 1336 1276 1217 1159 1103 1048 9943 9416 10875 1478 1413 135 1289 1229 1171 1114 1058 1004 9505 10625 1494 1429 1365 1303 1243 1184 1126 1069 1014 9598 10375 1511 1445 138 1318 1257 1197 1138 1081 1025 9696 10125 1528 1462 1397 1333 1271 121 1151 1093 1036 98 9875 1547 1479 1413 1349 1286 1225 1165 1106 1048 9908 9625 1566 1498 1431 1366 1302 124 1179 1119 106 1002
117
9375 1586 1517 145 1384 1319 1256 1194 1133 1073 1014 9125 1607 1537 1469 1402 1336 1272 1209 1147 1087 1027 8875 1629 1558 1489 1421 1355 129 1226 1163 1101 104 8625 1652 158 151 1441 1374 1308 1243 1179 1116 1054 8375 1676 1603 1532 1462 1394 1327 1261 1195 1131 1068 8125 17 1627 1555 1484 1415 1346 1279 1213 1148 1084 7875 1726 1652 1579 1507 1436 1367 1299 1231 1165 11 7625 1753 1678 1604 1531 1459 1389 1319 1251 1183 1116 7375 1781 1704 1629 1556 1483 1411 1341 1271 1202 1134 7125 1809 1732 1656 1581 1508 1435 1363 1292 1222 1152 6875 1839 1761 1684 1608 1533 146 1387 1314 1243 1172 6625 187 1791 1713 1636 156 1485 1411 1337 1264 1192 6375 1903 1823 1744 1666 1589 1512 1437 1362 1287 1214 6125 1936 1855 1775 1696 1618 1541 1464 1387 1312 1236 5875 197 1889 1808 1728 1649 157 1492 1414 1337 126 5625 2006 1923 1842 1761 1681 1601 1522 1443 1364 1285 5375 2043 196 1877 1795 1714 1633 1553 1473 1392 1312 5125 2081 1997 1914 1832 1749 1668 1586 1504 1422 134 4875 212 2036 1952 1869 1786 1704 1621 1538 1454 137 4625 2161 2076 1992 1909 1825 1741 1658 1573 1488 1403 4375 2203 2118 2034 195 1866 1782 1697 1611 1525 1437 4125 2246 2161 2077 1993 1909 1824 1738 1652 1564 1474 3875 229 2206 2123 2039 1955 1869 1783 1695 1606 1515 3625 2336 2253 217 2087 2003 1918 1831 1742 1651 1558 3375 2383 2302 222 2138 2055 197 1882 1793 1701 1606 3125 2432 2353 2273 2192 211 2026 1938 1848 1755 1658 2875 2482 2405 2328 225 217 2086 20 1909 1815 1715 2625 2533 2461 2387 2312 2234 2153 2067 1977 1881 178 2375 2586 2518 2449 2378 2304 2226 2142 2052 1955 1851 2125 264 2579 2516 2451 2381 2306 2225 2136 2039 1933 1875 2696 2642 2587 2529 2466 2396 2319 2232 2134 2026 1625 2753 2709 2664 2614 256 2497 2425 2341 2244 2133 1375 2811 278 2746 2708 2664 2611 2546 2468 2373 226 1125 2871 2854 2835 2811 278 2739 2685 2615 2524 2411 875 2932 2932 293 2923 2909 2885 2846 2787 2706 2595 625 2995 3014 3031 3045 3052 3049 3031 2989 2922 2824 375 3058 3098 3138 3175 3208 3234 3245 3223 3179 3109 125 3124 3185 3247 331 3373 3436 35 3483 3467 3451
x(mm) y(mm) 23625 25875 28125 30375 32625 34875 37125 39375 41625 43875
19875 7877 747 7071 6679 6294 5915 554 5168 4799 4432 19625 7872 7466 7067 6676 6291 5912 5538 5166 4798 4431 19375 7869 7463 7065 6674 6289 591 5536 5165 4797 443 19125 7868 7462 7063 6673 6288 591 5535 5165 4797 443 18875 7868 7462 7063 6673 6288 591 5535 5165 4796 443 18625 787 7463 7065 6674 6289 591 5536 5165 4797 443 18375 7873 7466 7067 6676 6291 5912 5537 5166 4797 443 18125 7878 747 7071 6679 6294 5914 5539 5167 4798 4431 17875 7884 7476 7076 6684 6298 5917 5542 5169 4799 4431 17625 7893 7483 7083 6689 6303 5921 5545 5172 4801 4432 17375 7903 7492 7091 6696 6309 5926 5549 5175 4803 4433 17125 7914 7503 71 6704 6316 5932 5553 5178 4806 4435 16875 7928 7515 7111 6714 6324 5939 5559 5182 4809 4436 16625 7943 7529 7123 6725 6333 5947 5565 5187 4812 4438 16375 796 7544 7137 6737 6343 5955 5572 5192 4815 444 16125 7979 7561 7152 675 6355 5965 558 5198 4819 4442
118
15875 8001 7581 7169 6765 6368 5976 5589 5205 4824 4445 15625 8024 7601 7188 6781 6382 5987 5598 5212 4829 4447 15375 8049 7624 7208 6799 6397 6 5608 522 4834 445 15125 8077 7649 723 6819 6414 6014 562 5229 484 4453 14875 8107 7676 7254 684 6432 603 5632 5238 4847 4457 14625 8139 7705 728 6862 6451 6046 5645 5248 4854 4461 14375 8174 7737 7308 6887 6472 6064 566 5259 4861 4465 14125 8211 777 7338 6913 6495 6083 5675 5271 4869 4469 13875 8251 7806 737 6941 6519 6103 5691 5283 4878 4474 13625 8294 7845 7405 6972 6545 6125 5709 5297 4887 4479 13375 834 7886 7441 7004 6573 6148 5728 5311 4897 4484 13125 8388 793 748 7038 6603 6173 5748 5326 4907 449 12875 844 7977 7522 7075 6634 62 5769 5343 4918 4496 12625 8495 8026 7566 7114 6668 6228 5792 536 493 4502 12375 8553 8079 7613 7155 6703 6258 5816 5378 4943 4509 12125 8615 8135 7663 7199 6741 6289 5842 5398 4956 4517 11875 868 8194 7716 7245 6781 6323 5869 5418 4971 4524 11625 8749 8256 7771 7294 6823 6358 5898 544 4986 4532 11375 8822 8322 783 7346 6868 6396 5928 5463 5002 4541 11125 8899 8392 7892 7401 6915 6435 596 5488 5018 455 10875 898 8465 7958 7458 6965 6477 5994 5514 5036 456 10625 9066 8542 8027 7519 7018 6521 6029 5541 5055 457 10375 9155 8624 81 7583 7073 6568 6067 557 5075 4581 10125 925 8709 8177 7651 7131 6617 6107 56 5095 4592 9875 9349 8799 8257 7722 7193 6669 6149 5632 5117 4604 9625 9454 8894 8342 7797 7257 6723 6193 5665 514 4617 9375 9564 8994 8431 7875 7325 678 6239 5701 5165 463 9125 9679 9098 8525 7958 7397 684 6288 5738 519 4644 8875 98 9208 8624 8045 7472 6904 6339 5777 5217 4659 8625 9927 9324 8727 8137 7551 6971 6393 5819 5246 4674 8375 1006 9445 8836 8233 7635 7041 645 5862 5276 4691 8125 102 9572 895 8334 7722 7115 651 5908 5307 4708 7875 1035 9706 907 844 7814 7192 6573 5956 5341 4726 7625 105 9846 9197 8552 7911 7274 664 6007 5376 4745 7375 1066 9994 933 867 8014 7361 671 6061 5413 4766 7125 1083 1015 947 8794 8121 7452 6784 6118 5452 4787 6875 1101 1031 9617 8925 8235 7548 6862 6178 5494 481 6625 112 1049 9773 9063 8356 765 6945 6241 5537 4834 6375 114 1067 9937 9209 8483 7757 7033 6308 5584 4859 6125 1161 1086 1011 9364 8618 7872 7126 638 5634 4887 5875 1183 1106 103 9528 8761 7993 7225 6456 5686 4916 5625 1207 1128 1049 9703 8914 8123 7331 6537 5743 4947 5375 1231 1151 107 9889 9076 8261 7443 6624 5803 498 5125 1258 1175 1092 1009 925 8409 7564 6717 5867 5015 4875 1286 1201 1116 103 9436 8567 7694 6816 5936 5053 4625 1316 1229 1142 1053 9637 8738 7833 6924 601 5094 4375 1349 1259 1169 1078 9853 8922 7983 7039 609 5138 4125 1384 1292 1199 1104 1009 912 8146 7164 6177 5186 3875 1422 1327 1231 1133 1034 9336 8321 7299 627 5237 3625 1463 1365 1266 1165 1062 957 8512 7445 637 5291 3375 1508 1407 1304 1199 1092 9824 8719 7603 6479 middot535 3125 1557 1453 1346 1237 1124 101 8943 7773 6595 5412 2875 1612 1504 1393 1278 116 104 9185 7956 6719 5478 2625 1673 1561 1444 1323 1199 1073 9446 8152 6851 5546 2375 1741 1624 1501 1373 1242 1108 9725 8359 6989 5617 2125 1818 1695 1565 1429 1289 1146 1002 8575 713 5687 1875 1906 1775 1636 149 1339 1186 1032 8792 727 5755 1625 2007 1868 1716 1556 1392 1227 1062 9001 7401 5818
119
1375 1125 875 625 375 125
2127 2271 2449 2679 2994 3436
1975 2103 226
2467 2776 3361
1807 1912 2032 2173 2333 2469
1629 1707 1788 1863 191
1868
1447 1501 1548 1575 1559 1454
1266 1301 1324 1324 1279 1163
109 1111 112
1107 1058 9548
9183 9311 934
9205 8813 8043
7514 7591 7611 7544 735
6956
5873 5918 5953 5988 6049 6199
F6 Freezer Wall Simulation Output Including Anti-sweat Condenser Tube
INPUT PARAMETERS
Section Dimensions (mm) Width Length Depth Steel skin thickness Plastic skin thickness
5600 2000 1580 6500 2500
Mesh Geometry dx dy Number nodes in x-direction Number nodes in y-direction Number of steel skin nodes (including corner 00) Steel nodes under the seal Tube located at node
2800 2500 20 80
11 2 to 10 6
Steel skin conductivity (Wm K)
Foam insulation conductivity (Wm K) Plastic skin conductivity (Wm K)
Outside h (Wm2 K) Inside h (Wm2 K) Outside Temp (C) Inside Temp (C)
5400 27000E-02 1500 6870 6410 2100 -1000
OUPUT PARAMETERS
Number of iterations 879
ID Heat Flux Thru Wall (Wm2) 1362
Heat Transfer Along Metal Skin Under Seal node to node qm[Wm2] Qm[W]
2 3 -15024E+04 -1543 3 4 -15111E+04 -1552 4 5 -15205E+04 -1562 5 6 -15310E+04 -1572 6 7 5828 5986 7 8 5690 5844 8 9 5535 5684 9 10 5348 5492
Maximum difference (Is) 1356
j qleft[W] qright[W] -1 -1566 5928
120
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63
0 -62085E-02 -31363E-02 -5 9522E-02 -40097E-02 -44286E-02 -30955E-02 -33621E-02 -21814E-02 -25242E-02 -1 4577E-02 -1 8767E-02 -9 6252E-03 -13815E-02 -58162E-03 -10387E-02 -31499E-03 -73398E-03 -1 6265E-03 -54353E-03 -10285E-04
-35309E-03 27805E-04 -23882E-03 65891E-04 -16265E-03 14208E-03 -1 24 55E-03 14207E-03 -48371E-04 14207E-03 -10285E-04 10398E-03 -10285E-04 10399E-03 -10281E-04 10398E-03 -48371E-04 65891E-04 -1 02 85E-04 27805E-04 -86465E-04 16377E-04 -48375E-04 -52182E-04 -86465E-04 -97886E-04 -1 2455E-03 -13979E-03 -1 7788E-03 -16645E-03 -19692E-03 -21597E-03 -24263E-03 -25786E-03 -30357E-03 -30357E-03 -33404E-03 -35309E-03 -3 7975E-03 -3 9879E-03 -41784E-03 -44450E-03 -45974E-03 -49402E-03 -50164E-03 -53592E-03 -54353E-03 -58162E-03 -58543E-03 -62733E-03 -62733E-03 -66923E-03 -66542E-03 -71493E-03 -70351E-03 -75303E-03 -74541E-03 -7 9111E-03 -77969E-03 -83301E-03 -81397E-03 -87491E-03 -85206E-03 -90919E-03 -88634E-03 -94728E-03 -92062E-03 -97775E-03 -95109E-03 -10158E-02 -98537E-03 -10463E-02 -1 0158E-02 -10768E-02 -1 04 63E-02 -11073E-02 -10692E-02 -11377E-02 -10996E-02 -11644E-02 -11225E-02 -1 1949E-02 -11492E-02 -12215E-02 -11758E-02 -12444E-02 -11949E-02 -12672E-02 -12177E-02 -12901E-02 -12368E-02 -13129E-02 -12596E-02 -1 3282E-02 -12748E-02 -1 351 OE-02 -1 2977E-02 -13701E-02 -13129E-02 -1 3853E-02 -13282E-02 -14005E-02 -1 3434E-02 -14158E-02 -13586E-02 -14310E-02 -1 3701E-02 -14463E-02
121
64 -1 3815E-02 -1 4577E-02 65 -1 392 9E-02 -14691E-02 66 -14005E-02 -14767E-02 67 -14120E-02 -14881E-02 68 -14196E-02 -14958E-02 69 -1 4272E-02 -15034E-02 70 -14310E-02 -15110E-02 71 -1 4386E-02 -1 5148E-02 72 -14424E-02 -15186E-02 73 -14463E-02 -15224E-02 74 -14501E-02 -1 5262E-02 75 -14501E-02 -1 5300E-02 76 -14539E-02 -15262E-02 77 -14539E-02 -15300E-02 78 -1 4539E-02 -15262E-02 79 -14501E-02 -1 5300E-02
Qleft [Wj -1653 Qright [Wj 5163 Percent entering cabinet 2380
Freezer Nodal Temperatures (Condenser Tube)
x(mm) y(mm) 14 42 70 98 126 154 182 210 238 266
19875 9606 8457 7334 6235 516 4107 3075 2064 107 00944 19625 9596 8448 7325 6227 5152 4099 3068 2056 1064 00882 19375 9591 8443 732 6222 5148 4095 3064 2053 106 00850 19125 9591 8443 732 6222 5147 4095 3064 2052 106 00847 18875 9596 8448 7325 6226 5151 4099 3067 2056 1063 00873 18625 9606 8457 7334 6235 5159 4106 3074 2062 1069 00928 18375 9621 8472 7347 6248 5171 4118 3085 2072 1078 01013 18125 9641 8491 7366 6265 5188 4133 3099 2085 109 01128 17875 9666 8514 7388 6287 5208 4152 3117 2102 1106 01272 17625 9696 8543 7416 6313 5233 4176 3139 2123 1125 01447 17375 9731 8577 7448 6343 5262 4203 3165 2147 1147 01652 17125 9772 8616 7485 6378 5295 4234 3194 2174 1173 01888 16875 9817 8659 7526 6418 5333 427 3228 2206 1202 02156 16625 9868 8708 7573 6462 5375 431 3265 224 1234 02455 16375 9924 8762 7624 6511 5421 4353 3306 2279 127 02786 16125 9985 8821 7681 6565 5472 4402 3352 2322 131 03149 15875 1005 8885 7742 6624 5528 4454 3401 2368 1353 03546 15625 1012 8954 7809 6687 5588 4511 3455 2418 1399 03976 15375 102 9029 7881 6755 5653 4573 3513 2472 145 04441 15125 1029 911 7958 6829 5723 4639 3575 253 1504 0494 14875 1038 9196 804 6907 5798 4709 3641 2592 1562 05474 14625 1047 9287 8128 6991 5877 4784 3712 2659 1623 06045 14375 1057 9385 8221 708 5962 4865 3787 2729 1689 06652 14125 1068 9488 832 7175 6052 495 3868 2804 1759 07297 13875 1079 9597 8424 7275 6147 504 3952 2884 1833 07981 13625 1091 9713 8535 738 6247 5135 4042 2968 1911 08704 13375 1104 9834 8651 7491 6353 5235 4136 3056 1993 09466 13125 1117 9962 8774 7608 6464 534 4236 315 208 1027 12875 1131 101 8902 7731 6581 5451 434 3248 2172 1112 12625 1146 1024 9037 786 6704 5568 445 3351 2268 1201 12375 1161 1038 9178 7995 6833 569 4566 3459 2369 1294
122
12125 1177 1054 9326 8136 6967 5818 4686 3572 2475 1392 11875 1194 107 9481 8284 7108 5951 4813 3691 2585 1494 11625 1211 1087 9642 8439 7256 6091 4945 3815 2701 1602 11375 1229 1104 981 86 7409 6237 5083 3945 2822 1714 11125 1248 1122 9985 8768 757 639 5227 4081 2949 1832 10875 1268 1141 1017 8943 7737 6549 5378 4222 3082 1954 10625 1288 1161 1036 9125 7911 6714 5534 437 322 2083 10375 1309 1181 1055 9314 8092 6887 5698 4524 3364 2217 10125 1331 1203 1076 9511 8281 7067 5868 4685 3514 2356 9875 1354 1225 1097 9716 8477 7254 6046 4852 3671 2502 9625 1378 1248 1119 9929 8681 7448 6231 5026 3835 2654 9375 1402 1271 1142 1015 8893 7651 6423 5208 4005 2813 9125 1428 1296 1166 1038 9113 7861 6623 5398 4183 2979 8875 1454 1321 1191 1062 9342 808 6832 5595 4369 3152 8625 1481 1348 1216 1086 9579 8308 7049 5801 4562 3333 8375 1509 1375 1243 1112 9826 8545 7275 6015 4764 3522 8125 1538 1403 127 1139 1008 8791 751 6238 4975 3719 7875 1568 1432 1299 1166 1035 9047 7755 6472 5196 3925 7625 1598 1462 1328 1195 1063 9314 8011 6715 5426 4142 7375 163 1494 1358 1224 1091 9591 8278 697 5667 4368 7125 1663 1526 139 1255 1121 9881 8556 7236 5919 4606 6875 1697 1559 1422 1287 1152 1018 8847 7514 6184 4855 6625 1731 1593 1456 132 1185 105 9151 7806 6462 5118 6375 1767 1629 1491 1355 1218 1083 9469 8113 6755 5394 6125 1804 1665 1527 139 1254 1117 9804 8435 7063 5686 5875 1842 1703 1565 1428 129 1153 1015 8774 7388 5995 5625 1881 1742 1604 1466 1329 1191 1052 9133 7732 6322 5375 1921 1782 1644 1507 1369 1231 1091 9511 8097 6669 5125 1962 1824 1686 1549 1411 1272 1133 9913 8485 7039 4875 2004 1867 173 1593 1455 1317 1176 1034 8899 7435 4625 2047 1912 1776 164 1502 1363 1223 108 9341 7859 4375 2092 1958 1823 1688 1552 1413 1272 1128 9816 8315 4125 2138 2005 1873 1739 1604 1466 1325 1181 1033 8807 3875 2184 2055 1925 1793 166 1523 1382 1238 1088 934 3625 2232 2106 1979 1851 1719 1584 1444 1299 1148 992 3375 2282 216 2037 1911 1783 1649 1511 1366 1214 1055 3125 2332 2215 2097 1976 1851 1721 1584 1439 1286 1125 2875 2384 2273 2161 2045 1925 1798 1663 152 1366 1202 2625 2436 2334 2229 212 2005 1883 1751 1609 1455 1288 2375 249 2397 2301 22 2093 1976 1849 1708 1554 1384 2125 2546 2463 2377 2287 2188 2079 1957 182 1666 1493 1875 2602 2532 2459 238 2293 2193 2079 1946 1793 16 17 1625 266 2605 2546 2482 2407 232 2215 2089 1939 176 1375 2719 2681 264 2592 2533 2461 2369 2253 2108 1928 1125 2779 2761 2739 271 2671 2618 2543 244 2305 2128 875 2841 2844 2844 2838 2822 2792 2739 2655 2535 2367 625 2903 293 2954 2974 2986 2984 2959 2899 2802 2658 375 2967 3018 3069 3117 316 3194 3209 3173 3108 3009 125 3032 3108 3186 3263 3342 3421 35 347 344 3412
x (nun) y (nun) 294 322 350 378 406 434 462 490 518 546
19875 -0865 -1811 -2743 -3663 -4573 -5474 -6368 -7257 -8141 -9022 19625 -0871 -1816 -2747 -3667 -4577 -5477 -6371 -7259 -8142 -9024 19375 -0874 -1819 -275 -3669 -4578 -5479 -6372 -726 -8143 -9024 19125 -0874 -1819 -275 -367 -4579 -5479 -6372 -726 -8144 -9025 18875 -0872 -1817 -2748 -3668 -4577 -5478 -6372 -7259 -8143 -9025
123
18625 -0867 -1812 -2744 -3664 -4574 -5476 -637 -7258 -8142 -9024 18375 -0859 -1805 -2738 -3659 -457 -5472 -6366 -7256 -8141 -9023 18125 -0848 -1796 -273 -3652 -4563 -5466 -6362 -7252 -8139 -9022 17875 -0835 -1784 -2719 -3642 -4555 -546 -6357 -7248 -8136 -9021 17625 -0819 -1769 -2706 -3631 -4546 -5451 -635 -7243 -8132 -9019 17375 -0800 -1752 -2691 -3618 -4534 -5442 -6342 -7237 -8128 -9017 17125 -0779 -1733 -2673 -3602 -4521 -5431 -6334 -7231 -8124 -9014 16875 -0754 -1711 -2654 -3585 -4506 -5418 -6323 -7223 -8119 -9012 16625 -0727 -1686 -2632 -3565 -4489 -5404 -6312 -7214 -8113 -9009 16375 -0697 -1659 -2607 -3544 -447 -5389 -6299 -7205 -8106 -9005 16125 -0664 -1629 -258 -352 -445 -5371 -6286 -7194 -8099 -9001 15875 -0627 -1596 -2551 -3494 -4428 -5353 -6271 -7183 -8091 -8997 15625 -0588 -156 -2519 -3466 -4404 -5332 -6254 -717 -8083 -8993 15375 -0545 -1522 -2484 -3436 -4377 -531 -6236 -7157 -8074 -8988 15125 -0500 -148 -2447 -3403 -4349 -5287 -6217 -7143 -8064 -8983 14875 -0451 -1436 -2408 -3368 -4319 -5261 -6197 -7127 -8053 -8977 14625 -0399 -1388 -2365 -3331 -4287 -5234 -6175 -7111 -8042 -8971 14375 -0343 -1338 -232 -3291 -4253 -5206 -6152 -7093 -803 -8965 14125 -0284 -1284 -2272 -3249 -4216 -5175 -6127 -7074 -8017 -8958 13875 -0221 -1228 -2221 -3204 -4177 -5143 -6101 -7054 -8004 -8951 13625 -0155 -1168 -2168 -3157 -4137 -5108 -6073 -7033 -7989 -8943 13375 -0085 -1104 -2111 -3107 -4093 -5072 -6044 -7011 -7974 -8935 13125 -0011 -1037 -2051 -3054 -4048 -5034 -6013 -6987 -7958 -8927 12875 0065 -0966 -1988 -2998 -4 -4993 -598 -6963 -7941 -8918 12625 01474 -0892 -1922 -294 -3949 -4951 -5946 -6937 -7924 -8909 12375 0233 -0815 -1852 -2878 -3896 -4906 -591 -6909 -7905 -8899 12125 03229 -0733 -1779 -2814 -384 -4859 -5872 -688 -7885 -8888 11875 0417 -0648 -1702 -2746 -3782 -481 -5832 -685 -7865 -8877 11625 05157 -0558 -1622 -2675 -372 -4758 -5791 -6819 -7843 -8866 11375 06189 -0464 -1537 -2601 -3656 -4704 -5747 -6785 -7821 -8854 11125 07269 -0366 -1449 -2523 -3589 -4648 -5701 -675 -7797 -8841 10875 08398 -0263 -1357 -2441 -3518 -4588 -5653 -6714 -7772 -8828 10625 09577 -0156 -126 -2356 -3444 -4526 -5603 -6676 -7746 -8814 10375 1081 -0044 -116 -2267 -3367 -4461 -555 -6636 -7718 -88 10125 121 00732 -1054 -2174 -3286 -4393 -5495 -6594 -769 -8785 9875 1344 01957 -0943 -2076 -3202 -4322 -5437 -655 -766 -8769 9625 1484 03238 -0828 -1974 -3113 -4247 -5377 -6504 -7628 -8752 9375 1631 04575 -0708 -1867 -302 -4169 -5314 -6456 -7596 -8734 9125 1784 05974 -0582 -1755 -2923 -4087 -5247 -6405 -7561 -8716 8875 1944 07436 -0450 -1638 -2822 -4001 -5178 -6352 -7525 -8697 8625 2111 08966 -0312 -1516 -2715 -3911 -5105 -6296 -7487 -8676 8375 2286 1057 -0167 -1387 -2604 -3817 -5028 -6238 -7447 -8655 8125 2469 1224 -0015 -1253 -2486 -3718 -4948 -6177 -7405 -8633 7875 2661 14 0143 -1111 -2363 -3614 -4863 -6112 -736 -8609 7625 2861 1584 031 -0962 -2234 -3504 -4774 -6044 -7314 -8584 7375 3072 1778 04856 -0806 -2097 -3389 -468 -5972 -7265 -8558 7125 3293 1982 06704 -0641 -1954 -3267 -4581 -5896 -7213 -853 6875 3526 2196 08652 -0467 -1802 -3138 -4476 -5816 -7158 -8501 6625 3771 2422 1071 -0283 -1641 -3002 -4366 -5732 -71 -847 6375 403 2661 1288 -0089 -1471 -2858 -4248 -5642 -7038 -8437 6125 4303 2914 1519 01168 -1291 -2705 -4124 -5547 -6973 -8402 5875 4593 3182 1763 03357 -11 -2542 -3991 -5445 -6904 -8365 5625 49 3467 2023 05686 -0896 -2369 -385 -5338 -683 -8326 5375 5227 3771 23 08169 -0678 -2185 -37 -5223 -6751 -8284 5125 5576 4095 2596 1082 -0446 -1988 -354 -5101 -6668 -8239 4875 5949 4442 2913 1366 -0198 -1778 -337 -4971 -6579 -8193 4625 635 4814 3254 167 00669 -1553 -3187 -4832 -6485 -8143 4375 6781 5215 3619 1997 03519 -1313 -2993 -4685 -6385 -809
124
4125 7246 5647 4014 2349 06577 -1055 -2785 -4528 -6279 -8036 3875 775 6116 444 2728 0986 -0780 -2565 -4362 -6168 -7978 3625 8299 6625 4902 3137 1339 -0486 -233 -4187 -6051 -7919 3375 8899 718 5404 3579 1717 -0173 -2082 -4003 -593 -7859 3125 9558 7787 595 4057 2122 01586 -1823 -3813 -5806 -7798 2875 1028 8455 6545 4573 2555 0508 -1553 -3618 -568 -7739 2625 1109 9192 7197 513 3014 0872 -1277 -3422 -5558 -7683 2375 12 1001 7912 5729 3497 1245 -1002 -3233 -5442 -7633 2125 1301 1093 8698 6373 3998 1618 -0739 -3059 -534 -7592 1875 1418 1196 9566 7058 4508 1975 -0503 -2914 -5262 -7564 1625 1552 1314 1053 778 5007 2292 -0319 -2818 -5218 -7554 1375 171 1452 116 8525 5462 2528 -0224 -2798 -5226 -7564 1125 19 1616 1281 9263 5815 2621 -0272 -2892 -5304 -7597 875 2136 182 1417 9928 5968 2477 -0537 -3151 -5478 -7651 625 244 2095 1569 1037 575 1953 -112 -3637 -5773 -7713 375 2845 2514 1726 1027 4873 0854 -2146 -4427 -6224 -7757 125 3384 3296 1814 8879 2904 -1057 -3745 -5602 -6885 -7725
F bull 7 Seal Simulation Source Code and Ouput
Program Seal
c This program simulates the heat transfer characteristics of an c idealized refrigerator door gasket The steady-state temperature c profile is determined numerically from a 2-D finite difference c code
cxxxxxxxxxxxxx Parameters and Variablesxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
integer NNNWnsurfijjlloopiters real emmissigmakhihoTiTodelsNN real depthareatolkair
parameter (N=6) parameter (NN=20) parameter (W=7) parameter (nsurf=4N-l) parameter (emmis=09) parameter (sigma=567e-8) parameter (k=03) parameter (kair=0026) parameter (hi=641) parameter (ho=687) parameter (Ti=1032) parameter (To=209) parameter (sNN=02) parameter (del=sNNNN) parameter (depth=10) parameter (area=deldepth) parameter (tol=10)
real x(Onsurf)y(Onsurf)len(ONOnsurf) real F(OnsurfOnsurf) real T(-lNN+lONN)radl(nsurf+l)rad(Onsurf) real Eb(Onsurf)bvector(nsurf+l)Amatrix(nsurf+lnsurf+l) real difasumqsumqtotqin(NN-l) real rlr2r3r4r5
125
real clc2c3c4c5c6c7
open (lfilemiddotGasketoutposition-rewind) open (2file=Gasket(q)outpositionmiddotrewind)
cxxxxxxxxxxxxx Determine Viewfactors xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
call Points(Ndelnsurfxy) call length(Ndelnsurfxylen) call Vfactor(NdelnsurflenF)
cxxxxxxxxxxxxx Resistors (C-m2W)
c Interior x- and y-directions rl=delk
c Exterior to outdoor ambient r2=1ho
c Exterior to indoor ambient r3-1hi
c Radiation r4=(1-emmis)emmis
c Air r5=delkair
xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
cxxxxxxxxxxxxx Guass-Siedel Iteration xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
c Begin massive loop to determine the steady-state temperature c distribution across the section First update the interior nodes c by considering the radiative heat transfer among the interior c surfaces The radiative transfer is updated by calling a routine c which computes the new radiosities every iteration Loop until c tolerance is met
c Initialize temperature field do 10 i=ONN
do 11 jONN T(ij)=50
11 continue 10 continue
do 15 j=ONN T(-1j)=250 T(NN+lj)=50
15 continue
c Set temperatures for row y=O and row y=NN do 20 i=ONN
T(iO)=fl(idel) T(iNN)=f2(idel)
20 continue
cxxxxxxxxxxxxx Begin Iteration xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
loop=l iters=l do while (loop eq 1)
c Update radiosities using new temps and update interior surface nodes
call Jsolver(FemmissigmaTNNNWnsurfradlradEb + bvectorAmatrix)
c interior corners cl=area (2rl) c2=arearl
126
c3=area (2rl) c4=arearl c5=arear4 c6=1(cl+c2+c3+c4)
T(WW)=c6(clT(W+lW)+c2T(W-lW)+c3T(WW+l)+ + c4T(WW-l)+c5(rad(0)-Eb(0raquo)
cl=arearl c2=area(2rl) c3=area(2rl) c4=arearl c5=arear4 c6-1(cl+c2+c3+c4) T(W+NW)=c6(clT(W+N+lW)+c2T(W+N-lW)+c3T(W+NW+l)+
+ c4T(W+NW-l)+c5(rad(N)-Eb(Nraquo) clarearl c2-area (2rl) c3-arearl c4=area(2rl) c5=arear4 c6=1(cl+c2+c3+c4) T(W+NW+N)=c6 (clT(W+N+lW+N)+c2T(W+N-lW+N) +c3T(W+NW+N+l)+
+ c4T(W+NW+N-l)+c5(rad(2N)-Eb(2Nraquo) cl=area(2rl) c2=arearl c3=arearl c4=area(2rl) c5=arear4 c6=1(cl+c2+c3+c4) T(WW+N)=c6 (clT(W+lW+N) +c2T(W-lW+N)+c3T(WW+N+l) +
+ c4T(WW+N-l)+c5(rad(3N)-Eb(3Nraquo)
c Interior surface y=W jl=l do 22 i=W+lW+N-l
cl=area(2rl) c2=area (2rl) c4=arearl c5=arear4 c7=arear5 c6=1(cl+c2+c4+c7) T(iW)=c6(clT(i+lW)+c2T(i-lW)+
+ c7T(iW+l)+c4T(iW-l)+c5(rad(jl)-Eb(jlraquo) jl=j1+1
22 continue
c Interior surface y=N+W jl=3N-l do 25 i=W+lW+N-l
cl=area(2rl) c2=area (2rl) c3=arearl c5=arear4 c7=arear5 c6=1(cl+c2+c3+c7) T(iW+N)=c6(clT(i+lW+N)+c2T(i-lW+N)+
+ c7T(iW+N-l)+c3T(iW+N+l)+c5(rad(jl)-Eb(jlraquo) jl=jl-l
25 continue
c interior surface x=W jl=4N-l do 30 j=W+lW+N-l
c2=arearl
127
c3=area (2rl) c4=area(2rl) c5-arear4 c7-arear5 c6-1(c2+c3+c4+c7) T(Wj)-c6(c7T(W+lj)+c2T(W-lj)+c3T(Wj+l)+
+ c4T(Wj-l)+c5(rad(jl)-Eb(jl))) jl=jl-l
30 continue
c interior surface x=W+N jl=N+l do 35 j-W+lW+N-l
cl=arearl c3=area(2rl) c4=area (2rl) c5-arear4 c7-arear5 c6-1(cl+c3+c4+c7) T(W+Nj)=c6(clT(W+N+lj)+c7T(W+N-lj)+c3T(W+Nj+l)+
+ c4T(W+Nj-l)+c5(rad(jl)-Eb(jl))) jl=j1+1
35 continue
c Interior air nodes do 37 j=W+lN+W-l
do 38 i=W+lN+W-l call sseqn(Tr5r5r5r5areaareaareaareaijNN)
38 continue 37 continue
c Solid nodes do 40 i=lNN-l
do 45 jlW-l call sseqn(TrlrlrlrlareaareaareaareaijNN)
45 continue do 50 j=W+N+lNN-l
call sseqn(TrlrlrlrlareaareaareaareaijNN) 50 continue 40 continue
do 55 j=WW+N do 60 i=lW-l
call sseqn(TrlrlrlrlareaareaareaareaijNN) 60 continue
do 65 i=W+N+lNN-l call sseqn(TrlrlrlrlareaareaareaareaijNN)
65 continue 55 continue
c Side boundaries do 70 j=lNN-l
call sseqn(Trlr2rlrlareaareaarea2area20jNN) call sseqn(Tr3rlrlrlareaareaarea2area2NNjNN)
70 continue
c Apply energy balance around the boundary of the gasket to determine c stopping criterium dif
dif-OO dif=dif+(area(2rl))(T(00)-T(01)) dif=dif+(area(2rl))(T(0NN)-T(0NN-l)) do 90 i=lNN-l
dif=dif+(arearl)(T(iO)-T(il)) dif=dif+(arearl)(T(iNN)-T(iNN-l))
128
90 continue dif=dif+(area(2r1raquo(T(NN0)-T(NN1raquo dif=dif+(area(2r1raquo(T(NNNN)-T(NNNN-1raquo
do 95 j=1NN-1 dif=dif+(arear2)(To-T(0jraquo dif-dif+(arear3)(Ti-T(NNjraquo
95 continue
print dif
c Stopping criterium if (dif It toll then
loop-O endif if (iters eq 10000) then
loop=O endif
iters=iters+1 end do
cxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx c Compute heat flux into the cabinet
qsum=OO asum=OO do 97 j=1NN-1
qin(j)=hiarea(T(NNj)-Ti) qsum=qsum+qin(j) asum=asum+area
97 continue qtot=qsumasum write(2) heat flux to interior [Wm2)qtot
do 100 j=NNO-l write(l) (T(ij)i=ONN)
100 continue
pause stop end
c----------------------------------------------------------------------shyc------~----------------------------------------------------------------
Subroutine Points(Ndelnsurfxy)
integer Nnsurfi real delincrx(Onsurf)y(Onsurf)
x(O)=OO y(0)=del2
c Points along y=O edge incr-OO do 10 i=lN
y(i)=OO x(i)=(del2)+incr incr=incr+del
10 continue
c Points along x=Ndel edge incr=OO do 20 i=N+12N
x(i)=Ndel
129
y(i)-(del2)+incr incr-incr+del
20 continue
c Points along y=Ndel edge incr=OO do 30 i=3N2N+l-1
y(i)-Ndel x(i)=(del2)+incr incr-incr+del
30 continue
c Points along x-O edge incr=OO do 40 i-nsurf3n+l-1
xli) -00 y(i)-laquo3del)2)+incr incr-incr+del
40 continue
return end
c----------------------------------------------------------------------shyc-----------------------------------------------------------------------
Subroutine length(Ndelnsurfxylen)
integer Nnsurfij real dellen(ONOnsurf)x(Onsurf)y(Onsurf)
c Special case surface 0 do 10 j=Onsurf
len(0j)=sqrtlaquox(0)-x(jraquo2+(y(0)-y(jraquo2) 10 continue
c Surfaces along y=O do 20 i=IN-l
do 30 j=Onsurf len(ij)=sqrtlaquox(i)-x(jraquo2+(y(i)-y(jraquo2)
30 continue 20 continue
c Special case surface N do 50 j=Onsurf
len(Nj)=sqrtlaquox(N)-x(jraquo2+(y(N)-y(jraquo2) 50 continue
return end
c----------------------------------------------------------------------shyc-----------------------------------------------------------------------
Subroutine Vfactor(NdelnsurflenF)
integer Nnsurfijjlj2 real dellen(ONOnsurf)F(OnsurfOnsurf)Lzero
c Determine viewfactors for special case of surface 0 Lzero=delsqrt(20) do 10 j=Onsurf
if (j eq 0) then F(Oj)=OO
elseif (j eq nsurf) then F(Oj)=(len(Oj)+len(10)-len(00)-len(ljraquo(2Lzero)
else F(0j)=(len(0j)+len(lj+l)-len(Oj+l)-len(ljraquo(2Lzero)
130
endif 10 continue
c Determine viewfactors for surfaces on edge y-O
do 20 i=IN-l do 30 j=Onsurf
if (i eq j) then F(ij)=OO
elseif (j eq nsurf) then F(ij)=(len(ij)+len(i+l0)-len(i0)-len(i+ljraquo(2de1)
else F(ij)=(len(ij)+len(i+lj+l)-len(ij+l)-len(i+ljraquo(2del)
endif sum=sum+F(ij)
30 continue 20 continue
c Determine viewfactors for all other surfaces do 40 iON-l
do 50 j=03N-l F(i+Nj+N)=F(ij)
50 continue do 60 j=3Nnsurf
F(i+Nj-3N)=F(ij) 60 continue
do 70 j=02N-1 F(i+2Nj+2N)=F(ij)
70 continue do 80 j=2Nnsurf
F(i+2Nj-2N)=F(ij) 80 continue
do 90 j=ON-l F(i+3Nj+3N)=F(ij)
90 continue do 100 j=Nnsurf
F(i+3Nj-N)=F(ij) 100 continue
40 continue
return end
c----------------------------------------------------------------------shyc-----------------------------------------------------------------------
Subroutine Jsolver(FemmissigmaTNNNWnsurfradlradEb + bvectorAmatrix)
integer NNNnsurfij real emmissigmaF(OnsurfOnsurf) real T(-INN+10NN)rad1(nsurf+l)rad(0nsurf) real Eb(0nsurf)bvector(nsurf+1)Amatrix(nsurf+lnsurf+l)surn
c Compute Eb for all surfaces do 10 i-ON-l
Eb(i)=sigma(T(i+WW) 4) Eb(i+N)=sigma(T(W+Ni+W)4)
10 continue incr=W+N do 20 i=0N-1
Eb(i+2N)=siqrna(T(incrW+N) 4) Eb(i+3N)=sigma(T(Wincr)4) incr=incr-1
20 continue
131
c Assign values to vector b do 30 i=Onsurf
bvector(i+l)-(emmis(l-emmisraquoEb(i) 30 continue
c Assign values to matrix A do 40 i-Onsurf
do SO j=Onsurf Amatrix(i+lj+l)--F(ij)
SO continue 40 continue
c Override diagonal terms do 60 i-Onsurf
sum-OO do 70 j-Onsurf
sum-sum+F(ij) 70 continue
Amatrix(i+li+l)-(emmis(l-emmisraquo+sum 60 continue
c Call routine to solve the set of equations for unknown JS call gaussy(Amatrixbvectorradlnsurf+l)
do 80 i=Onsurf rad(i)=radl(i+l)
80 continue
return end
c----------------------------------------------------------------------shyc-----------------------------------------------------------------------
Subroutine Gaussy(abxn) c
integer nkiimaxjkplusllplus real a(nn)b(n)x(n)amaxbtempatemp
+ aeon sum
do 28 k=l n amax=OO do 4 i=kn if(abs(a(ikraquo-abs(amaxraquo442
2 amax=a(ik) imax=i
4 continue if(abs(amax)-0le-15)101014
10 printO equations are not independent return
14 btemp=b(k) b(k)=b(imax) b(imax)=btemp do 18 j=kn
atemp=a(k j) a(kj)=a(imaxj)
18 a(imaxj)=atemp kplus=k+l if(k-n)222828
22 do 24 i=kplusn b(i)=b(i)-b(k)a(ik)a(kk) acon=a(ik) do 24 j=kn
24 a(ij)=a(ij)-a(kj)acona(kk) 28 continue
132
l=n 32 sum=OO
if(1-n)343838 34 lplus-1+1
do 36 j-lplusn 36 sum=sum+a(lj)x(j) 38 continue
x(l)-(b(l)-sum)a(ll) if(1-1)424240
40 1-1-1 goto 32
42 return end
c----------------------------------------------------------------------shyc-----------------------------------------------------------------------
Subroutine sseqn(TriplusriminusrjplusrjminusAiplus + AiminusAjplusAjminusijNN)
c This subroutine computes the temperature at node (ij) c given the temperatures of the surrounding nodes and c the resistances leading to these nodes
integer ijNN real T(-1NN+10NN)riplusriminusrjplusrjminus real AiplusAiminusAjplusAjminus real c1c2c3c4c5
c1=Aiplusriplus c2=Aiminusriminus c3=Ajplusrjplus c4=Ajminusrjminus c5=1(c1+c2+c3+c4)
T(ij)=c5(c1T(i+1j)+c2T(i-1j)+c3T(ij+1)+c4T(ij-1raquo
return end
c----------------------------------------------------------------------shyc----------------------------------------------------------------------shy
real function f1(x) c door BC
real x f1-18520 - 23413x
return end
c----------------------------------------------------------------------shyc----------------------------------------------------------------------shy
real function f2(x) c wall BC
real x f2=18128 - 3475x
return end
c----------------------------------------------------------------------shyc----------------------------------------------------------------------shy
133
Fresh Food Compartment Simulations Results
Run 1 The prescribed temperature profiles are
Wall 19203 - 1908 x Door 19203 - 1206 x
(x is in meters)
Outdoor Ambient = 210 degC Local Indoor Ambient = 1533 degC
Run 2 The prescribed temperature profiles are
Wall 18989 - 2024 x Door 19078 - 1326 x
(x is in meters)
Outdoor Ambient = 210 degC Local Indoor Ambient = 1496 degC
Run 3 The prescribed temperature profiles are
Wall 1895 - 1998 x Door 19053 - 1384 x
(x is in meters)
Outdoor Ambient = 208 degC Local Indoor Ambient = 1491 degC
Ayem~ Values Wall 1905 - 1977 x Door 1913 - 1384 x
(x is in meters)
Ave Outdoor Ambient = 209 degC Ave Local Indoor Ambient =1507 degC
Loss from Fresh Food == 10 W
134
Freezer Compartment Simulations Results
Run 1 The prescribed temperature profiles are
Wall 1821 - 343 x Door 18606 - 2354 x
(x is in meters)
Outdoor Ambient = 210 degC Local Indoor Ambient = 1029 degC
Run 2 The prescribed temperature profiles are
Wall 18182 - 3542 x Door 18544 - 2398 x
(x is in meters)
Outdoor Ambient = 210 degC Local Indoor Ambient = 1042 degC
Run 3 The prescribed temperature profiles are
Wall 17993 - 3452 x Door 18411 - 2272 x
(x is in meters)
Outdoor Ambient = 208 degC Local Indoor Ambient = 1024 degC
Ayera~e Values Wall 18128 - 3475 x Door 18520 - 23413 x
(x is in meters)
Ave Outdoor Ambient = 209 degC Ave Local Indoor Ambient = 1032 degC
Loss from Fresh Food = 157 W
135
LIST OF FIGURES
Page 11 Door Seal Region Cross Section 3 12 Mullion Region Cross Section 4
31 Model Used To Calculate One-dimensional Load 7
41 SteelSkin Temperature Profile Thermocouple Placement 12 42 Steel Skin Temperature Plot for Fresh Food Compartment 13 43 Steel Skin Temperature Plot for Freezer 14 44 Thermopile Test Apparatus 15 45 Thermopile Placement ~ 16 46 Thermocouple Drag Test Apparatus 17 47 Drag Profiles (Fresh Food) 18 48 Drag Profiles (Freezer) 19 49 Heat Flow Paths in Mullion 21 410 Mullion Face Plate Cross Section 22 411 Mullion Temperature Profile 23 412 Electric Heater Location 25 413 Mullion Temperature Profile With Heater On (Center) 26
51 Wall Heat Conduction Model Sketch 29 52 Non-adiabatic Door Seal 31 53 Fresh Food Wall Temperature Distribution 34 54 Freezer Wall Temperature Distribution 35 55 Tube Location for Simulation 36 56 Fresh Food Wall Temperature Distribution
Including Warm Anti-sweat Tube 37 57 Freezer Wall Temperature Distribution
Including Warm Anti-sweat Tube 38 58 Load Due to Condenser Tube for Various Tube Placements 39 59 ~ercentage of Heat Entering Cabinet for Various Tube Placements 39 510 Seal Simulation Mesh Layout 40 511 Seal Cavity Mesh Details 41 512 Seal Temperature Distribution (Fresh Food) 44 513 Seal Temperature Distribution (Freezer) 45
61 Refrigerator System Load Graph 46 62 Cabinet Loads Graph 47
A1 Fumed Silica Test Apparatus 59 A2 Fumed Silica Test Facility Schematic 60 A3 Time vs Temperature for Unpacked Run 61 A4 Natural Log Time vs Temperature for Unpacked Run 62 A5 Conductivity vs Bulk Density 63 A5 Diffusivity vs Bulk Density 64
viii
LIST OF FIGURES (CONTINUED)
Page
C1 Location of Anti-sweat Devices and Overall Dimensions of Test Refrigerator 73
C2 Fresh Food Compartment Interior Dimensions 74 C3 Fresh Food Door75 C4 Freezer Interior Dimensions 76 C5 Freezer Door76
D1 Data Acquisition and Control System 78
E1 Steel Skin Temperature Plot for Fresh Food Compartment (Run 2) 79 E2 Steel Skin Temperature Plot for Fresh Food Compartment (Run 3) 80 E3 Steel Skin Temperature Plot for Freezer (Run 2) 80 E4 Steel Skin Temperature Plot for Freezer (Run 3) 81 E5 Mullion Temperature Profile Run 2 (Heater Off) 84 E6 Mullion Temperature Profile Run 3 (Heater Off) 85 E7 Mullion Temperature Profile Run 4 (Heater Off) 85 E8 Mullion Temperature Profile Run 5 (Heater Off) 86 E9 Mullion Temperature Profile Run 2 (CenterHeater On) 87 E10 Mullion Temperature Profile Run 3 (CenterHeater On) 88 E11 Mullion Temperature Profile Run 1 (LeftHeater On) 88 E12 Mullion Temperature Profile Run 2 (LeftHeater On) 89 E13 Mullion Temperature Profile Run 3 (LeftHeater On) 89 E14 Mullion Temperature Profile Run 1 (RightHeater On) 90 E15 Mullion Temperature Profile Run 2 (RightHeater On) 90 E16 Mullion Temperature Profile Run 3 (RightHeater On) 91
F1 Generic Nodal Resistor Network 92
IX
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I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I
I I I I I I I I I I I I I I I I I I I I I I
1 INTRODUCTION
New regulations recently announced by the Department ofEnergy call for substantial
energy efficiency increases for household appliances by 1993 The refrigerator is of
particular interest since it is the largest household consumer of electricity and accounts for a
large part of the 8 of the electricity used in the US for food-cooling both residential and
commercial In addition to efficiency standards regulations are being imposed on the use
of CFCs completely banning their use by the year 2000 (Braswell 1988)
The objective of this thesis is to present an analysis of all heat transfer paths from the
surroundings to the interior food compartments of the refrigerator under closed door
conditions Both experimental and numerical methods are used as a means to determine the
overall cabinet load as well as the load due to each pathway The study is focused on a
particular unit for practical purposes However the methods implemented may be applied
to any make or model to aid in the search for high efficiency cabinets
All loads determined in this study are strictly cabinet loads and not the loads seen by the
refrigerator system The thermal load on the cabinet is comprised of three main parts (i)
the load due to the one-dimensional heat transfer through the walls and doors to the food
compartments away froin the edges (ii) the load due to edge effects that is heat transfer
into the food storage compartments via paths around the perimeter of the cabinet aperture
and (iii) other miscellaneous sources
(11)
The determination of qlD is straightforward and is discussed in detail in Chapter 3 The
edge load must be broken down into several parts for examination
qedge = qwall + qdoor + qseal + qrnullon + qtubeave (12)
where
qwall heat input due to conduction along the wall steel flange
qdoo heat input due to conduction along the door steel flange
qseal heat conduction directly through the door seal
1
heat input due to conduction in the mullion region with the additional input from an anti-sweat heater
qtubeave heat input due to cabinet anti-sweat condenser tube averaged over the cycle time
heat input due to cabinet anti-sweat condenser tube
heat input due to conduction in the mullion region electric heater off
It is assumed that an electric anti-sweat heater in the mullion region is in use for the entire
cycle The test unit chosen for this study required this region to be heated almost
continually to eliminate condensation This load is represented by qmulloo in Eq (12)
The load qmulloff is due to heat conduction to the interior compartments at the mullion
region when the electric heater is off Although this value does not appear in the edge load
definition it is still important to detennine for sake of comparison with the value of
qmulloo The load due to the presence of an anti-sweat condenser loop around the aperture
of the cabinet is defmed as qtube Since this load is present for the on cycle only it must be
integrated over the cycle time to be included in Eq (12) hence the tenn qtubeave
The tenn qroisc is expressed as
qmisc = qfanave + qdefrostave + qcompave (13)
where
qfanave heat input from the evaporator fan averaged over the cycle time
qdefrostave heat input from the defrost heaters averaged over defrost cycle time
qcompave heat input from elevated exterior walls near the running compressor
Figure 11 is a cross sectional drawing of the door seal area of the test refrigerator
examined to detennine qwalI qdoor and~ The figure includes materials and their
properties taken from Incropera and Dewitt (1985)
2
400 ~I-I~ 065~
065 Only dimension that is different for the freezer
200
kltWIm-K)
Outer Steel Skin 540 312~ Polyurethane Wall Insulation 0027 0015- Inner Plastic Skin 015 009~
~ Rubber Gasket 03 017fm1I ~ ~ Glass Fiber Door Insulation 004 0023
All dimensions in millimeters
1 in= 254mm
Fig 11 Door Seal Region Cross Section
3
Figure 12 is a drawing of the mullion region cross section of the test refrigerator examined
to detennine ltlmullon and ltlmulloff
FREEZER
Freezer Gasket
Fresh Food Gasket
FRESH FOOD COMPARTMENT
Fig 12 Mullion Region Cross Section
The remainder of this thesis is devoted to the analysis of the closed door cabinet loads and
the experimental and numerical techniques used for their detennination
An experimental investigation of fumed silica as an alternative insulation for the refrigerator
is presented in Appendix A Although this appears to be a departure from the main topic
a relation exists The desire of higher efficiency requires a search for equal if not better
cabinet insulations that do not incorporate the use of ozone damaging CFCs Testing is
done to detennine the thennal conductivity and diffusivity of fumed silica for several
densities
4
2 LITERATURE REVIEW
The new energy standards imposed by the Department ofEnergy have sparked research in
the area of refrigerator efficiency and alternative refrigerants A study by Turiel and
Heydari (1988) focused on several ways to improve the efficiency of refrigerator-freezers
and freezers
Various classes for the study were chosen however the paper presents extensive results for
the most common variety a top-mounted automatic defrost refrigeratorfreezer The
design options considered were those changes that can be incorporated into the existing
refrigerator design Two types of improvements are noted (i) changes that increase energy
efficiency by decreasing the heat transfer into the cabinet and (ii) changes that increase the
efficiency by reducing auxiliary electricity use or improving the refrigeration system Type
(i) changes include Foam insulation substitution increased insulation thickness double
door gaskets improved foam insulation evacuated insulation panels and reduced heat load
of through-the-door feature Type (ii) changes include High efficiency compressor
substitution adaptive defrost fan and fan motor improvement anti-sweat heater switch
increased evaporator surface area hybrid evaporator enhanced heat transfer surfaces
mixed refrigerants improved expansion valve fluid control valve two-compressor system
use of natural convective currents and location of compressor condenser and evaporator
fan motor
Turiel and Heydari used a model developed by Little (1982) to carry out the energy use
simulations This model is a steady-state energy use simulation which computes the heat
leakage to the cabinet and then determines the energy needed to maintain the interior
ambient temperatures dictated by the OOE test procedure Turiel and Heydari present the
energy consumption figures for a 18 cubic foot top-mounted automatic defrost
refrigeratorfreezer as a baseline case They find that 74 of the total energy is accounted
for by the compressor 11 is for the anti-sweat heaters 10 is for the fans and 5 is
for the defrost heaters for a total of 947 kWhyr Also about 10 of the compressor
energy use is for the removal of internal heat generated by the evaporator fan motor defrost
heater and anti-sweat heaters
Several subsequent simulations were performed each time adding a design option that was
projected to improve efficiency The improvement levels were added cumulatively and
results were given on compressor run time heat leakage rate into the cabinet compressor
5
power demand at the operating point fan motor operating power for the evaporator and
condenser fans anti-sweat heater power and total daily and annual energy consumption
The goal here was to achieve by the last level of improvement the minimum energy
consumption that is technologically feasible One important fmding for all product classes
tested the highest efficiency was obtained by the use of evacuated panels in the planar
walls For example for the top-mounted automatic defrost unit the minimum energy use
was 515 kWyr
Finally an energy usevolume relation was developed from a linear regression obtained
from simulation results The resulting fit was shown as
Energy Use = Cl + C2Adjusted Volume
The constant Cl indicates the direct energy use to remove the cabinet loads associated with
the fan motors and heaters The slope C2 is an indicator of the rate of change ofenergy use
with a change in the adjusted volume This value reflects the rate of cabinet heat gain The
adjusted volume is the volume of the fresh food compartment plus 163 times the volume
of the freezer Turiel and Heydari produced a series of regressions for all of the defined
levels of design improvements allowing easy comparison at a specific adjusted volume
6
3 ONE-DIMENSIONAL WALL AND DOOR LOADS
In this section the overall steady cabinet load is calculated without considering the addition
of edge loading This load qlD is dermed as the heat transfer from the exterior
environment to the interior of the refrigerator under nonnal closed-door operating
conditions through four primary conductive paths (i) fresh food compartment walls (ii)
freezer walls (iii) fresh food door and (iv) freezer door In a later chapter the load due to
edge loading will be examined more closely
31 One-dimensional Heat Transfer Model
The steady conductive heat transfer through the walls of the refrigerator cabinet is
computed using a simple computer program written by Qausing (1983) This program
estimates inside and outside effective heat transfer coefficients using a flat plate natural
convection correlation Using these coefficients and the material properties and dimensions
of the wall insulation the one-dimensional heat transfer through the cabinet walls is
approximated for the fresh food and freezer compartments Figure 31 shows the
resistances and boundary conditions use in the model
Fig 31 Model Used To Calculate One-dimensional Load
7
The model provides flexibility for varying several parameters This allows application to
various types of refrigerator walls and doors Table 31 lists the input and output
parameters for the model The source code of the simulation along with the output for
completed runs are included in Appendix B
Table 31 One-dimensional Model Parameters
Input Parameters
To K (F) Room ambient temperature
Ti K (F) Interior ambient temperature
LiDs m (ft) WalVdoor insUlation thickness
kiDs Wm-K (Btuhr-ft-F) WalVdoor insulation thermal conductivity
A m2 (ft2) Cabinet surface area
Output
beo Wm2K (Btuhr-ft2_F) Exterior convective heat transfer coefficient
bei Wm2K (Btuhr-ft2-F) Interior convective heat transfer coefficient
hro Wm2K (Btuhr-ft2_F) Exterior effective radiative heat transfer coefficient
hri Wm2-K (Btuhr-ft2_F) Interior effective radiative heat transfer coefficient
qlD W (Btuhr) Heat transfer rate through specified section
32 Determination of Effective Heat Transfer Coefficients
The simulation developed automatically estimates the inside and outside effective heat
transfer coefficients This effective value is the sum of the convective and radiative
components which are defined below
The radiative heat transfer coefficients are computed iteratively using eqs (31) and (32)
assuming (i) gray walls at temperatures T wi or Two with emissivities poundi and Eo (ii) black
surroundings at Ti or To and (iii) walls can see surroundings only
(31)
(32)
8
The convective heat transfer coefficients are estimated from a flat plate natural convection
correlation developed by Clausing (1983) In the laminar regime (Ra lt 1()9) the Nusselt
number based on the film temperature is given by Eq (33)
NUf = 052 Ra4 (33)
For the turbulent regime (Ra ~ 109) the Nusselt number becomes
NUf = 009 Raf3 (34)
where in both cases
Tw+T_ Film temperature T f == 2
Lc == Vertical surface characteristic length g == Gravitational acceleration f3 == Thermal expansion coefficient v == Kinematic viscosity Tw == Vertical wall surface temperature T_ == Outsideinside ambient temperature
kf == Air thermal conductivity
The film temperature characteristic length Nusselt number and Rayleigh number will
have different values for the inside surface compared with the outside surface of the
cabinet Therefore the inside and outside convective heat transfer coefficients are
determined separately from eqs (35) and (36)
(35)
- NUfo kfohco - (36)Leo
9
33 Results
The four primary regions analyzed are (i) the fresh food compartment walls (ii) fresh food
door (iii) freezer walls and (iv) the freezer door The values for the input parameters
ltLins kins A) are taken from a full-size unit that is used for the experimental analysis
presented in Chapter 4 The room temperature is used for the model parameter To Also
the fresh food ambient Tee and the freezer ambient Tfz are substituted for Ti when
suitable in order to closely simulate real operating conditions The results are given in
Table 32
Table 32 Results From One-dimensional Load Analysis
Input
Section TooC eF)
Tj degC eF)
Lins m (ft)
kins Wm-K (Btuhr-ft-OF)
A m2 (fi2)
Fresh Food 21 4 0045 0027 242 Walls (698) (392) (0148) (0015) (2605)
Fresh Food 21 4 0040 0040 089 Door (698) (392) (0131) (0023) (958)
Freezer 21 -10 0056 0027 110 Walls (698) (-140) (0184) (0015) (1184)
Freezer 21 -10 0040 0040 034 Door (698) (-140) (0131) (0023) (366)
Output
Section hco Wm2-K cBtuhr-ft2-Fl
hro Wm2-K iJtuhr -ft2-Fgt
hci Wm2-K (Btuhr-ft2-F)
hri Wm2-K 1Btuhr-ft2-F)
qlD W (Btuhr)
Fresh Food 130 544 198 461 209 Walls (23) (96) (35) (81) (713)
Fresh Food 144 542 218 463 117 Door (25) (95) (38) (82) (399)
Freezer 143 542 226 397 143 Walls (25) (95) (39) (70) (488)
Freezer 164 538 259 400 81 Door (29) (94) (46) (70) (276)
herro =687 Wm2 K (121 Btulhr-ft2-OF) Total qlD =550 W herrrr = 670 Wm2 K (118 Btulhr-ft2_0F) (1876 Btuhr)
herrrz = 641 Wm2 K (113 Btulhr-ft2-OF)
The load for our operating conditions is 550 W (1876 Btuhr) Once again this quantity
does not reflect the total cabinet load on the refrigerator cabinet Edge effects are analyzed
in detail in the following chapters Another important result is the values for the effective
10
inside and outside heat transfer coefficients which are simply the sum of the convective
and radiative components The outside coefficient is heffo the fresh food coefficient is
heffff and the freezer coefficient is hefffz These numbers are used whenever film
coefficients are needed for computations
11
4 EXPERIMENT AL ANALYSIS
This section presents an experimental study performed on a full-size household
refrigerator In Chapter 3 we defined the load due to heat transfer through the walls and
doors of the cabinet as qlD The purpose of this experimental analysis is to quantify qwalh
qdoor qmulloff and Qrnullon and Qmisc Three types of tests are performed to accomplish
this task Descriptions of each are presented separately in the sections that follow
41 Temperature Profile Measurements
The refrigerator is instrumented with many thermocouples in various key areas to give
temperatures across the steel skin and to compare and verify the thermopile tests outlined
in the next section The four primary paths along the steel flange that are examined are the
wall-side fresh food door-side fresh food wall-side freezer and the door-side freezer
Five Type T 36 AWG thermocouples are placed along the skin for each path Figure 41
is a detailed drawing of the location of the thermocouples
Wall side TICs Door side TICs with 5 mm spacing with 5 mm spacing
Fig 41 Steel Skin Temperature Profile Thermocouple Placement
The wire leads are oriented so they run perpendicular to the temperature gradient so as to
reduce any effects of conduction along the wire to the bead The temperature data are fed to
the data acquisition system Each channel is a thermocouple input and is scanned at a rate
of 5 times a second The data are smoothed automatically by the software in blocks of 10
12
points for an average temperature every 2 seconds A full description of the data
acquisition and control system is provided in Appendix D
Data are collected for several runs to provide a good base to detennine average values since
the test conditions vary slightly from run to run To get a good measurement of the
temperature profIles along the steel flange the unit is shut off at the beginning of the run
and allowed to drift to quasi-steady conditions The presence of a large amount of thennal
mass (see Appendix C) within the refrigerator provides for a stable interior ambient
temperature during data collection The outer ambient is controlled by the room thennostat
which keeps the laboratory at a constant temperature to within plusmn1degC
Figure 42 is an example plot of a run that gives the temperature profIles along the steel
skin on the wall-side and door-side for the fresh food compartment
193
192
G 191 ~
i 19
middot5 189F
188
Run I iii --0 - Door Profile
~Imiddotmiddotmiddotmiddotmiddotmiddotmiddott 0 Wall Profue
i ~ i - - T =19273 - 001206x i i-- door i If ~
=-r~r==L~r=I ~ I +~~=~~~~~~~~~ middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot
Outdoor Ambient = 210 degC Fresh Food Ambient =48 degC
187-+----+----J------I----+---~
o 5 10 15 20 25
x (mm) 1 in= 254 mm
Fig 42 Steel Skin Temperature Plot for Fresh Food Compartment
The dashed line represents a linear least-squares fit for the door data and the solid line is the
corresponding fit for the cabinet wall data Each data point in the plot represents the
average temperature at that point over a period of time at quasi-steady conditions
Similarly Figure 43 is a plot of the temperature profIles for the freezer
13
186
184
a 182
~
i 18
5 178~
176
174
Run 1 t-- 1 1 --0 - Door Profde
P~P1 0 Wall Profile
- -LLl--=-+--shy- - Tdo = 18606 - O02354x i
or ~
=c==-rc1 1 ltb 1 ~
~~r--r- -r---shy0 5 10 15 20 25
x (mm) 1 in= 2S4mm
Fig 43 Steel Skin Temperature Plot for Freezer
A total of six separate runs were perfonned three for the fresh food compartment and three
for the freezer Plots for the other runs are located in Appendix E
From the figures above for the fresh food compartment the slope on the wall-side is
slightly steeper than the slope on the door-side In fact this trend is seen for all the runs
Therefore the heat conduction along the metal skin into the cabinet along the wall is
somewhat greater than that of the door For the freezer the slopes are nearly equal hence
the heat conduction along the wall skin and the door skin are nearly the same
42 Thermopile Testing
Another simple but important test is the use of a thennopile to measure the average
temperature difference at various locations on the steel flange regions of the unit Figure
44 is a schematic of the thennopile test set-up The thennopile is constructed from 36
AWG copperconstantan thennocouple wire
14
-
CopperConstan$t Junctions 285 mPt
IOmm
10mmThermopile
IOmm
Digital Multimeter
1 in= 254mm
Fig 44 Thermopile Test Apparatus
Five junctions are used for the fresh food compartment and three for the freezer The
junctions are mounted 10 mm (039 in) apart from one another along the steel skin beneath
the door seal Figure 45 is a detailed drawing of the lateral location of the thermopile
junctions
15
1 in =254 mm
Fig 45 Thermopile Placement
The thennopile provides an average temperature difference across the junctions The
output voltage must frrst be divided by the number of pairs of junctions and then translated
into a temperature difference using a referencing chart for the thennocouple wire Table
41 is a summary of the results from these tests The output voltages are read accurately to
within plusmn0002 mV The raw data and data reduction procedure are given in Appendix E
Table 41 Thermopile Output
Test Conditions Fresh Food aT Freezer aT TodegC
(OF) TffoC
(OF) Tfzoc
(OF) aTwallff degC
(Of) aTdoorffoc
(OFgt aTwallfzoC
(Of) aTdoorfzoC
(OFgt
1 210 (698)
48 (406)
-88 (162)
026 (047)
024 (043)
037 (067)
041 (074)
2 210 (698)
37 (387)
-87 (163)
027 (049)
026 (047)
038 (068)
040 (072)
3 208 (694)
37 (387)
-93 (153)
027 (049)
026 (047)
038 (068)
040 ( 072)
Average Values 209 (696)
40 (392)
-90 (158)
0267 (0481)
0253 (0455)
0377 (0679)
0403 (0725)
43 Thermocouple Drag Testing
One final technique applied is thennocouple drag testing This is a more qualitative method
to supply insight into what exactly is happening when the compressor is pumping wann
16
refrigerant through the anti-sweat tube that lines the perimeter of the cabinet aperture The
main objective of this test is not to give accurate temperature proftle infonnation but
instead to detennine the placement of the condenser tube This is needed as an input for
the numerical simulation of this region The reason that the temperature are not accurate is
the fact that the thermocouple is being dragged across a surface where good thermal contact
may not occur and significant energy may be generated Figure 46 is a schematic of the
apparatus used for drag testing
Power Supply
Data Acquisition System
Outer Metal Skin
Potentiometer
Inner Plastic Skin
Condenser Tube
Fig 46 Thermocouple Drag Test Apparatus
This device is quite simple yet very effective The type T 36 AWG thennocouple begins
at the interior boundary of the steel skin beneath the seal on the wall-side of the cabinet
The potentiometer is turned by hand moving the thennocouple oqtward along the skin
The temperature and location are stored simultaneously this way The thennocouple is kept
17
pressed against the steel flange by the seal The linear translation of the thennocouple is a
function of the output voltage Voutbull
s = 2mllT Vout (41)Yin
r =radius of potentiometer post =30 mm (012 in)
nT = total number of turns of potentiometer = 10
Vin = input voltage = 05 V
Vout = output voltage
Drag tests are run on the wall steel skin for both the fresh food compartment and the
freezer Runs are perfonned at four separate times the first being when the compressor
turns on Figure 47 is a plot of the drag proflles across the wall-side skin in the fresh food
compartment Figure 48 is a plot of the profiles in the freezer compartment The same
trends are generally seen for both regions The freezer profiles are simply shifted down in
temperature values as expected The temperature peak seems to move through time to
settle near the center of the flange region under the seal
31
30
29
G
i 28~
27
26~
25
24
23
e
Ji ~ i i i 1middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotlmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddoti~~
---l- Time 4
o Time 2 rr
i
0 5 10 15 20 x (mm)
Fig 47 Drag Profiles (Fresh Food)
18
26~--------+---------~-------4--------~
i ~
Time 1 24
22
20
18
16~~------+---------~-------4--------~
4 __
~~Time3
middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot_middotmiddot_middotmiddotimiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot
Outer Seal Edge o
o 5 10 15 20
x (mm)
Fig 48 Drag Profiles (Freezer)
44 Experimental Determination of qwall and qdoor
The results from the temperature profile and thennopile testing are used to detennine qwall
and qdoor according to the following defmitions
qwall = qwallff + qwallfz (42)
(43)
Where qwal1ff = heat conduction along wall-side fresh food compartment steel flange
qwallfz = heat conduction along wall-side freezer compartment steel flange
qdoorff = heat conduction along door-side fresh food compartment steel flange
qdoorfz = heat conduction along door-side freezer compartment steel flange
The trends derived from the fixed profiles exhibit generally good agreement with the
temperature differences seen by the thennopile For the fresh food compartment the
thennopile displays a slightly larger AT than what is seen in the profiles and both give a
19
slightly larger temperature difference for the wall-side compared with the door-side For
the freezer the temperature differences match closely on the wall-side however the doorshy
side AT is shown to be somewhat less than the wall-side AT for the fIXed thennocouple
measurements where the opposite is seen from the thennopile The worst discrepancy is
on the order of 10 and is probably due to the fact that the thennopile gives an average temperature difference at several vertical locations on the wall whereas the other method is
at one vertical location only
Since the thennopile produces an average temperature difference across the steel skin its
output is used to detennine the heat flux into the cabinet The refrigerator casing is being
used as a heat meter Thus the flux along the skin in the fresh food compartment on the
wall-side is
kmiddot ATwallffqwallff = m (44)
Ax
The load qwallJf is Eq (44) multiplied by the cross sectional area This area is the
thickness of the steel casing multiplied by the perimeter that is exposed to the room
ambient This perimeter varies for each of the two paths that comprise qwall and the two
paths that comprise qdoor The other cabinet loads are computed in a similar way and are
given in Table 42 The details of these values are given in Appendix E
Table 42 Experimental Determination of qwall and qdoor
Section Load W (BtuIhr)
qwallJf 28 (96)
qwallJz 21 (72)
qwall 49 (168)
qdoorff 33 (112)
qdoorJz 33
1112)
qdoor 66 (224)
20
45 Experimental Determination of qmulloff
The region that lies between the fresh food compartment and the freezer is called the
mullion The front portion of the mullion is covered by a thin steel face plate to provide a
suitable interface for the door seal magnets In this section the load due to heat conduction
along the mullion steel skin into the freezer and fresh food compartment is detennined
based on the experimental data
The heat transfer rate qmulloff is sum of two parts The first component is the heat
conduction along the steel plate into the fresh food compartment and the second is the
conduction into the freezer
qmulloff = qmulloffff + qmullofffz (45)
Figure 49 schematically illustrates paths of these two components
FREEZER
FRESH FOOD COMPARTMENT
Fig 49 Heat Flow Paths in Mullion
21
Ten 36 A WG type T thennocouples are mounted from top to bottom across the steel face
plate Figure 410 shows the cross section of the plate and the location and numbering of
the thennocouples
FREEZER
1bennocouplesSteel Face (5 mm spacing from
Plate bottom edge)
Freezer Gasket
Fresh Food Gasket
10 50
FRESH FOOD COMPARTMENT
1 in =254 mm
Fig 410 Mullion Face Plate Cross Section
Data are gathered from the ten thennocouples when the unit is shut off and allowed to drift
to a quasi-steady ambient temperature A total of five runs were perfonned Figure 411 is
a sample plot of the quasi-steady temperature profile All other plots are contained in
AppendixE
22
116
Run 1 I 115 ICcIIIII114 iii t ~mull~ =12~7 - 00~654xa
~ 113
rrfIIJ~~If112i 5 )mullfz 1= 1081~ + OOdl25X 111111 ~
11 oo+-t--t-iH-+-lo-shyiii i i Room Ambient = 2184 degc
109 middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1middot Fresh Ambient = 381 OC
108
1 10
I I I I I Freezer Ambient =-832 degc
2 3 4 5 6 7 8 9
TIC
Fig 411 Mullion Temperature Profile
The plot also shows two linear equations These represent linear fits to each side of the
peak temperature at TIC 7 The slopes (shown in degCmm) are used to detennine the heat
conduction to each compartment by eqs (46) and (47)
lmulloffff = km A (aT) (46)ax offff
qmul)offfz = km AIll) (47)ax offfz
The cross sectional area is the product of the face plate thickness (10 mm 0039 in) and
the length of the mullion (717 mm 2825 in) The average slopes from all five runs are
used to detennine qmulloffff and qroullofffz The results are given in Table 43
23
Table 43 Experimental Results from Mullion Analysis
Load W (Btuhr)
09qmullofUz (31)
07qmulloffff (24)
16qmuIlorr (55)
46 Experimental Determination of qmullon
In this section the load due to heat conduction along the mullion steel skin into the freezer
and fresh food compartment when an anti-sweat heater is on is experimentally determined
The test unit is equipped with an electric anti-sweat heater to eliminate condensation in the
mullion region The heater is installed on the back side of the plate and may be switched on
manually when needed It is a wire resistor type rated at 10 watts
The heat transfer rate qmullon is composed of two parts The first component is the heat
conduction along the steel plate into the fresh food compartment and the second is the
conduction into the freezer similar to ~ul1off
qmuIlon = ~ullonff + qmuIlonfz (48)
The location of the wire heater and the heat transfer paths are shown in Figure 412
24
FREEZER
qmullonfz
qmullonff
FRESH FOOD COMPARTMENT
Fig 412 Electric Heater Location
A series of tests are perfonned while the heater is on and the refrigerator is cycling
nonnally Three runs are done at each of three separate locations along the mullion
laterally (i) LEFT dermed as 180 mm (71 in) from the left-hand side of the unit (ii)
RIGHT 180 mm (71 in) from the right-hand side of the unit (iii) CENTER at center of
the mullion Figure 413 is a plot of the temperature profile across the face plate when the
heater is on for a specific test run The plots for all other runs are provided in Appendix E
The plot shows two profiles These represent the upper and lower limits as the unit cycles
The upper limit occurs just before the compressor turns on while the lower limit is at the
point in time just before the compressor shuts off At all times in between the profile
oscillates between the two limits maintaining nearly the same shape Once again a linear
fit is applied to the data on the fresh food side and the freezer side
25
30 iii imiddot iii i
29
28
27
Run 1
T mu
ill~~ 11 f = 26707 + 010776x Tmu11ff = 3128 - 00793x
Z +_ a 26~
I ~
middotmiddotmiddotbull-middotbullimiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotimiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotimiddotmiddotmiddotimiddotmiddot
24
25
e 23~ =H-T+H~i=i=
iimiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotimiddotmiddot T 11 ff = 27435 - 009504x 22 Tmullfz =21865 + 01l786x I m~ iii
21 -lmiddotmiddotmiddotmiddotmiddotmiddotmiddot-tmiddot Upper Limlt 0
20 middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotjmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotimiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddott 0 Lower Limit
19
0 1 2 3 4 5 6 7 8 9 10
TIC I
Fig 413 Mullion Temperature Profile With Heater On (Center)
Heat fluxes are computed identically to the method in Section 45 using the average slopes
from all nine runs The minimum value occurs just before to compressor turns on while
the maximum value occurs just before the compressor shuts off during normal cycling
The load is averaged over the cycle time which is approximately 50 for the test unit and
laboratory conditions The results are given in Table 44
Table 44 Experimental Results from Heater Analysis
Lower Profile Average W
(BtuIhr)
Upper Profile Average W
ffituhr)
qmullonfz 73
(249) 53
(181)
qmullonff 23 (78)
26 (89)
96 (32 7)
79 (270)
qmullon 88
300)
26
47 Determination of Qmisc
The load qoisc is comprised of three main parts The first is the load due to the evaporator
fan motor The fan that moves cool air in the cabinet also adds a thennalload Fans of this
type in use range from 8 - 16 watts The fan of our test unit is rated at 92 watts This
value must be integrated over the cycle time The cycle time for the unit is approximately
50 for the test conditions Thus the value of qfanave is 46 watts
The load qdefrostave is not determined experimentally Instead an estimate is obtained from
a similar study done by Turiel and Heydari (1988) This value is 5 watts which is an
average of the defrost heater input over the defrost cycle The defrost cycle can range from
10 - 12 hours of compressor run-time
The fmalload qcompave is detennined by measuring the cabinet surface temperature at the
region surrounding the compressor and computing the heat transfer locally The value is
found to be 2 watts Table 45 summarizes the results
Table 45 Miscellaneous Loads
Load W CBtuhr)
46 qfanave (15middotU
50 qdefrostave _07Ql
20 qcompave (68)
116 Qmisc (395)
27
s NUMERICAL SIMULATION
In this chapter a two-dimensional numerical model which is used to simulate the steadyshy
state heat transfer in the wall near the door seal is discussed The results from the model
include a computation of qwallff qwallfz and the complete temperature distribution across
the section The model is also used to estimate the additional cabinet load due to the
presence of an anti-sweat condenser tube embedded beneath the outer casing that runs
along the perimeter of the unit A separate model is presented which is used to simulate the
two-dimensional heat transfer across the door seal cross section The results are used to
determine qseal
51 Wall Model
A finite-difference technique is used to approximate the steady-state temperature
distribution in the wall section The technique is applied to solve the governing steady
two-dimensional heat conduction equation (assuming constant conductivity with no
generation)
(51)
Equation (52) is the basic fmite-difference representation of the conduction equation in a
homogeneous medium of constant conductivity with no heat generation (White 1988) In
Appendix F a complete list of all the model difference equations is provided
2(1+(3)Tij = (3Tij+l + Ti+lj+(3Tij-l + (3Ti-lj (52)
where (3 = (llxlly)2
28
Figure 51 is a sketch of the model representation of the refrigerator wall at the door seal region The dimensions shown are flexible parameters in the model The model allows for
slight changes in the geometry as well as changes in mesh size in both x and y directions
However the mesh size must remain uniform across the section
s5 s6
sl
Fig 51 Wall Heat Conduction Model Sketch
For each of N unknown nodal temperatures N simultaneous linear algebraic equations are obtained for N unknowns If N is large as is the case for this simulation an iterative
technique is preferred to solve the system ofequations A Fortran program has been
written to carry out the finite-difference iteration A copy of the code is given in Appendix
F A simple Guass-Seidel technique is employed for the differencing iteration At each
iteration an energy balance is done for the entire section In theory this balance should be
29
zero (heat entering) = (heat leaving) The iteration is continued until the difference
between heat entering and heat leaving is equal to 1 of the total heat entering the section
Table 51 defines the input parameters for the simulation
Table 51 Wall Simulation Input
Code Parameter Definition
To C (F) Exterior surrounding ambient temperature
Ti C (F) Interior ambient temperature
lan Wm-K (Btuhr-ft-F) Steel skin conductivity
kp Wm-K (Btuhr-ft-F) Plastic skin conductivity
kins Wm-K (Btuhr-ft-F) Wall insulation conductivity
heffo Wm2-K (Btuhr-ft2-F) Outside effective heat transfer coefficient
hefti Wm2-K (Btuhr-ft2-F) Inside effective heat transfer coefficient
dm mm (in) Steel skin thickness
dp mm (in) Plastic skin thickness
dx mm (in) Mesh size x direction
dy mm (in) Meshsizeydirection
sl mm (in) Wall width
s2 mm (in) Wall length
b mm (in) Effective Perimeter
s3 mm (in) Seal indentation
s4 mm (in) Seal width
s5 mm (in) Depth of steel skin into cabinet along seal boundary
s6 mm (in) Width of plastic skin along seal boundary
The model assumes that the boundary that lies along the door seal is adiabatic This allows
the separation of the wall section from the rest of the geometry in this region The seal and
door can then be treated separately later A simple calculation is done to validate this
assumption
30
Steel Skin (Refrigerator wall)
Seal (k = 02 Wm-K)
Fig 52 Non-adiabatic Door Seal
A 2 degC temperature difference AT is imposed across the seal This is a slight overshy
estimate based on the experimental data An estimate of the conductive heat flux is
determined from Eq (53)
ATqerror=k- (53) Ax
qrror =02 Wm-C o~Cm =20 Wm2
The heat flux ql for the fresh food compartment is determined in Appendix E to be 14418
Wm2 Therefore qerror represents approximately 13 of the total flux Hence this
term is neglected in this study
Two other possible sources of error are associated with the fmite-difference technique itself
(Ozisik 1980) The fIrSt is called truncation error and arises from the discretization of the
second-order derivative in the steady conduction equation The second is referred to as the
round-offerror which is due to the fact that numerical calculations are carried out only to a
finite number of decimal places Repeated solution with smaller increments shows that the
truncation error is negligible The precision of the energy balance is evidence that the
round-off errors are negligible
31
S2 Wall Simulation to Determine qwall
The finite-difference model is used to detennine the wall-side heat transfer along the steel
skin However more valuable information is yielded from the simulation The nodal
temperature distribution is detennined which gives insight into the direction and magnitude
of heat fluxes throughout the section The fresh food compartment and the freezer are both
simulated to detennine qwallff and qwallJz respectively Table 52 is the list of the values
used for the model input parameters for both cases
Table S2
Code Parameter
To C eF)
Ti C eF)
kIn Wm-K (Btuhr-ft-F)
kp Wm-K (Btuhr-ft-F)
kins Wm-K (Btulhr-ft-F)
heffo Wm2-K (Btuhr-ft2_F)
heffi Wm2-K (Btuhr-ft2-F)
dm mm (in)
dp mm (in)
dx mm (in)
dy mm (in)
sl mm (in)
s2 mm (in)
b mm (in)
s3 mm (in)
s4 mm (in)
s5 mm (in)
s6 mm (in)
Input Values
Fresh Food 210 (698) 40
(392) 540 (312) 015 (009) 0027 0015t 687 (121) 670 (118) 065
(0026) 25
(0098) 225
(0088) 25
(0098) 450
(1772) 2000 (7874) 2960
(11653) 225
(0088) 2025 (0797) 225
(0886) 2025 (0797)
32
Freezer 210 (698) -10
(140) 540middot (312) 015 (009) 0027 (0015) 687 (121) 641 (113) 065
(0026) 25
(0098) 28
(0088) 25
Jo098) 540
(2125) 2000 (7874) 1580
(6220) 28
(0110) 196
JO772) 224
(088t) 288
(1134)
The output from the simulation includes the entire nodal temperature field heat fluxes at
each node along the centerline heat fluxes from node to node along the steel skin beneath
the door seal and the value for qwallff and qwallcz These heat transfer values and the
nodal temperature distribution are listed in Appendix F
The quantities qwallff and qwallcz are determined by computing the heat fluxes from node to node along the centerline of the section subtracting the one-dimensional flux and then
multiplying by the cross sectional area for that node and summing to give the total heat
transfer rate The primary results are shown in Table 53
Table 53 Wall Simulation Results
Section
The temperature distributions are shown in the following two figures Figure 53 shows
the temperature contour for the fresh food results Figure 54 is the same plot for the
freezer results
Since the geometry of the refrigerator door is similar to that of the wall along the edges the
heat leakage to the food compartments along the door flange can be approximated as being
roughly the same as qwall This approximation of qdoor is a good means of estimating the
two prime contributors to the edge loss for various different refrigerators which may have
slightly different geometries as well as different material properties
33
i
3875
3625
TemplaquogtC)
-e
11111
20
18
16 3375
g 3125 14 -5 2875 ~ 122625 ~
2375~ 102125~
1875 8
1625
1375 6
1125
875 4
625
375
SteeVPlastic Liner Interface
Fig 53 Fresh Food Wall Temperature Distribution
34
i 4875
4625
4375
4125
3875
3625
3375 -
3125e g 2875
2625 ~ 2375 ~ 2125c (I)
1875 ~ 1625
1375
1125
875
625
375
125
Fig 54 Freezer Wall Temperature Distribution
Temp(OC)
20
15
10
5
0
-5
-10
35
53 Wall Edge Simulation to Determine qtube
The wall simulation is modified to include a constant temperature node placed beneath the
steel flange to represent the presence of an anti-sweat condenser tube The simulation is
perfonned for the specific conditions that are typical of the test unit as well as a range of
lateral tube locations For the test refrigerator the tube is located as shown in Figure 55
and is at 35degC (95 OJlt)
Outer Steel Skin
14625 mm 1
Inner Plastic Liner
Fig 55 Tube Location for Simulation
The quantity qtube is detennined by taking the fluxes along the vertical line to the left of
the tube subtracting the one-dimensional flux and then multiplying by the cross sectional
area for that node and summing to give the total heat transfer rate Again the fresh food
compartment and the freezer must be simulated separately to produce a total governed by
Eq (54)
(54)
Program output for the fresh food and freezer simulations is given in Appendix F Table
54 summarizes the results from the model
Table 54 Wall With Condenser Tube Simulation Results
Section Load W iBtubrl
qtubeff 46
(157)
qtubefz 28 (96)
qtube 74 (253)
qtube8ve (ave for 50 cycle time)
37 (126)
36
-I i c IJ
~
r 4875
4625
4375
4125
3875
3625
3375
3125
2875
2625
2375
2125
1875
1625
1375
1125
875
625
375
125
TempfC)
SteeVPlastic Liner Interface
35
30
25
20
15
10
5
Fig 56 Fresh Food Wall Temperature Distribution Including Warm Anti-sweat Tube
37
TempfC)4875
4625
4375
4125
3875
3625
3375 - 31258
2875g 2625fo 2375
3 2125 d vI 1875
~ 1625
1375
1125
875
625
375
125
SteeVPlastic Liner Interface
Fig 57 Freezer Wall Temperature Distribution Including Warm Anti-sweat Tube
38
40
30
20
10
0
-10
The heat fluxes at each node along the vertical line to the left of the tube are also computed
by the simulation This value quantifies the amount of heat that is moving toward the outer
boundary and is used to determine the percentage of heat entering the cabinet For the test
refrigerator this value is 18 for the fresh food compartment and 24 for the freezer
Several more simulation runs were done to find the effect of lateral placement of the tube on
the overall heat transfer and the percentage of heat entering Figure 58 and Figure 59
show the trends that are found
-~ a tUbe ~middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotlmiddotmiddotmiddot=middotmiddot=pmiddotmiddotmiddot=middot-1- =1
middot middot middoti middot middotmiddotmiddotmiddotmiddotmiddotmiddotmiddot bull middotmiddotmiddot i middotmiddotmiddotmiddot middotmiddot middotmiddot ~ middotmiddot
middotmiddotrmiddot-rmiddot 0 lwbeff middotlmiddotmiddot~middot Gmiddottmiddotmiddot9middotlmiddot
i i -0- lwbe i middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotimiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddot fz tmiddotEimiddotmiddot ~G- -~ -q- -
0 5 10 15 20 25 x(mm)
Fig 58 Load Due to Condenser Tube for Various Tube Placements
8
~ - 7
50
a 6
~ 5
~ en 4 ~
pound ~ 3
2
- 26
~ a 24
middots bO
pound 22c ~
~ 20
a = 18sect ~
16 0 5 10 15 20 25
x (mm)
Fig 59 Percentage of Heat Entering Cabinet for Various Tube Placements
39
54 Door Seal Simulation to Determine qseal
Another model is developed for the two-dimensional heat transfer through the door seal
This model is very similar to the one created for the wall section Once again a fIniteshy
difference technique is utilized to detennine the temperature distribution at steady-state
conditions Even though the cross sectional geometry of the seal is simplifIed to a square
with a hollow square with a centrally located cavity no closed-form solution can be
applied Therefore a simulation is needed
The fInite-difference representation of the two-dimensional steady Eq (55) using central
differencing is given by Ozisik (1980)
Ti-lj - 2Tij + Ti+lj + Tij-l - 2Tij + Tij+l = 0 (55) Ax2 Ay2
For this model a square mesh is applied reducing Eq (55) to
Ti-lj + Ti+lj + Tij-l + Tij+l - 4Tij = 0 (56)
x
Fig S10 Seal Simulation Mesh Layout
40
The nodes along the vertical surfaces at x=O and x=20 are subject to the convective
boundary conditions and governed by Eq (57) and Eq (58) respectively
2~xheffol 2~heffo2Ti+lj + Tij-l + Tij+l - (4 + k TiJ = - k To (57)
seal seal
2~heffffl 2~heffff2Ti-lj + Tij-l + TiJ+l - (4 + kseal Tij = - kseal Tff (58)
The nodes along the top and bottom outside surfaces are held at the prescribed temperature
profIles which are detennined from experimental data (see Section 41) The interior nodes
are subject to radiant e~change among themselves and conduction through what is assumed
to be stagnant air A closer look at the model of the hollow interior of the seal is shown in
Figure 511
Fig 511 Seal Cavity Mesh Details
Each interior node corresponds to a single gray surface with assumed emissivity of 09
Viewfactors for all surfaces are computed automatically before the iteration begins For
each iteration the effect of radiation within the enclosure is taken into account by updating
surface radiosities Jij Thus for nodes on interior surfaces an extra tenn is added to the
governing difference equation (Eb is the blackbody radiation)
41
~(J - Eb )1-pound IJ lj
A code written in Fortran is used to perfonn Guass-Seidel iteration of the difference
equations to compute the temperature distribution at mesh nodes (Code listing in Appendix
F) Once again convergence is based on an energy balance applied to the entire section
The iteration is continued until the difference between heat entering and heat leaving is
equal to 01 of the total heat entering the section Table 55 lists the input parameters
used in the model The fresh food compartment and the freezer compartment are simulated
separately
Table 55 Seal Simulation Input
Code Parameter Fresh Food Freezer
Number of nodes along outside edge 20 20
Number of nodes along inside edge 6 6 1 1Lx = fly mm (in) (0039) (0039)
210 210Outdoor ambient temperature degC (oF) (698) (698) 150 105Indoor local ambient temperature degC COF) 590J j509)
Outdoor heat transfer coefficient W m2-K 687 687 (121) (121)(Btuhr-ft2-F)
Indoor heat transfer coefficient Wm2-K 670 641 (118) (113)(Btuhr-ft2-F)
Gasket interior surface emissivity 09 09 03 03Gasket conductivity Wm-K (Btuhr-ft-F) (0173) (0173)
Wall-side Temperature Boundary 1905 - 1977x 1813 - 3475x Condition degC Door-side Temperature Boundary 1913 - 1384x 1852 - 2341x Condition degC
42
The load results are summarized in Table 56 below The program output is listed in
AppendixF
Table 56 Seal Simulation Results
Load W Section (BtuIhr)
10 Qsealff (34)
ljQsealfz (Sn
25qseal (85)
The steady-state temperature distribution is shown in the figures below Figure 512 is the
fresh food simulation and Figure 512 is the freezer simulation The direction of the heat
flow through the section is easily seen from these plots
43
Wall-side Boundary Temperature (C)
~~
I 20
195
i 19t 0
8 ~ 1859 -- ~
isis ~ ampJ gtshy 18 ~
11 ~ S ~ 175~
~ 17
165
x(mm)
Door-side Boundary
Fig 512 Seal Temperature Distribution (Fresh Food)
44
Wall-side Boundary Temperature (C)
Ii 19
185
18i f IQ 5 IQ
175-is-is I s 17j ~
5e 0C= 165
~ ~ 16
155
x(mm)
Door-side Boundary
Fig 513 Seal Temperature Distribution (Freezer)
45
6 DISCUSSION OF RESULTS
The heat transfer values detennined from the experimental analysis and the numerical
simulations are the various components that embody the cabinet load on the refrigerator It
is important to separate cabinet loads from system loads The system load can be thought
of as the total electrical energy consumption of the unit It has four basic components (i)
the compressor (ii) fans (iii) anti-sweat heaters and (iv) defrost heaters The first two
components the compressor and fans are the cost of removing heat from the cabinet This
amount of heat is equal to the cabinet load divided by the COP of the system The typical
energy consumption is shown schematically in Figure 61
System Load (Energy Consumption)
Defrost Heater (averaged over time
cycles every 10-12 hours of compressorrurt-time)
TuneCycle
Fig 61 Refrigerator System Load Graph
In a study done by Turiel and Heydari (1988) the compressor and fans accounted for 84
of the total system load for an 180 cubic foot top-mounted refrigerator Staley (1992)
found this value to be 86 for a similar unit Both of these studies used system analysis to
determine these numbers The energy consumption of the components were monitored
during operation The energy consumption of our test refrigerator can be determined in a
reverse manner from the cabinet load data If a COP of 1 is assumed the test refrigerator
46
compressor and fans accounts for 86 of the energy consumption to cool the cabinet This
compares favorably with the fmdings of Turiel and Heydari (1988) and Staley (1992)
Figure 62 is a schematic of the cabinet loads One possible load that is not included in the
figure is the heat input associated with the defrost drain tube that runs through the back
wall However this term is probably small relative to the other contributors
Cabinet Load
qseal qdoor
qwall
qmullon
qdefrostave
Fig 62 Cabinet Loads Graph
All the loads are determined in this study from either experimental measurements
numerical simulations or both Most of the loads are quasi-steady that is they do not
fluctuate significantly over the cycle time of the refrigerator There are four loads shown in
Figure 61 that are cyclical in nature The three loads that appear only while the
compressor is running are qcomp qfarb and qtube Also the refrigerator is subjected to a
load every time ice build-up is removed by the defrost heaters This load is averaged over
its own cycle time and shown in the graph as qdefrostave
47
61 Comparison of Simulation Results with Experimental nata
The majority of the cabinet loads are detennined from experimental data with the exception
of qseal and qtube The wall and door flange loads aremiddot also found from the numerical
simulation (see Chapter 5) The two-dimensional model detennines the wall-side heat
transfer along the steel skin into the food compartments No model is available to directly
detennine the heat transfer on the door-side However since the flange geometry on the
door-side is similar to the wall the value for qwall is considered to be a good estimate for
qdoor Table 61 gives these values determined from experimental measurements and the
simulation
Table 61 Comparison of Simulation and Experimental Values for qwall and qdoor
Experimental Result W Simulation Result W (BtuIhr) (BtuIhr)
qwallff 28 (96)
28 (96)
qwallz 21 (72)
27 (92)
qwall 49 (168)
55 (188)
ldoorff 33
(112) 28 (96)
qdoorfz 33
(112) 27 (92)
qdoor 66 (224)
55 (188)
The model predicts qwall to within 57 of the experimental value The agreement of the
estimate of qdoor with the experimental value is within 90
Some of the shortcomings in the model used in this investigation are
(i) Only the wall is modeled Ideally the entire region should be considered including the
door and seal (see Figure 11)
(ii) The flange geometry is simplified The steel casing skin in the flange region may bend
in more complex ways Also the plastic liner varies in thickness near the door seal
(iii) The mesh must be unifonn There is no means to vary how fme the mesh can be The
ideal situation would be to have a fine mesh near the edges and a course mesh far from the
seal
48
62 Mullion Analysis
The single largest edg~ load is found in the mullion section (329 of qedge and 94 of
qtol) This load is due to the electric anti-sweat heater installed on the backside of the face
plate The heater is rated at 10 watts and approximately 88 of that input enters the
interior of the cabinet as a thennalload This is probably due to the small surface area
exposed to the room and the low amount of convective heat transfer in the channel between
the fresh food and freezer doors With the heater on 88 watts is measured enter the food
chambers With the heater off only 16 watts enters the interior The addition of the
heater increases the mullion load 55 times Generally it is not necessary to use the
mullion heater at all times However for the test environment the heater nearly all the time
to eliminate sweating under the laboratory conditions
63 Seal Analysis
The heat conduction directly through the seal accounts for the smallest portion of the edge
loss (94 ofqedge and 27 of qtol) The numerical model to detennine these values uses
a simplified representation of the complex cross sectional geometry of an actual door seal
The various air pockets are reduced to a single hollow void There is no experimental data
to verify the model However the numbers and trends resulting from the simulation are
reasonable
64 Anti-sweat Condenser Tube Analysis
Thennocouple drag tests were perfonned to give insight into the nature of the temperature
profIles at the wall steel flange with the presence of an anti-sweat condenser tube The wall
heat transfer simulation model was modified to include the effect of this tube The heat
conduction to the interior increased by 76 at the wall flange region The amount of
additional loading due to the tube depends on several parameters location of the tube
temperature of the circulating refrigerant and local wall geometry Although the model is
flexible enough to handle vari01~S temperatures and limited geometrical changes only the
influence of tube position was investigated As the tube is moved towards the interior the
load increases For the test refrigerator about 20 of the heat flow was directed to the
interior compartments primarily along the steel skin
49
6S Overall Cabinet Load
The overall cabinet load is defined as a sum of three parts
(61)
The edge load is
qedge = qwall + qdoor + Qseal + Qrnullon + qtubeave (62)
where
qwall
qtubeave
heat input due to the conduction along the wall steel flange
heat input due to the conduction along the door steel flange
heat conduction directly through the door seal
heat input due to conduction in the mullion region with the additional input from anti-sweat heater
heat input due to cabinet anti-sweat condenser tube averaged over the cycle time
heat input due to cabinet anti-sweat condenser tube
qmulloff heat input due to conduction in the mullion region electric heater off
The terms of Qrnisc are defined as
qmisc = qfanave + qdefrostave + qcompave (63)
where
qfanave heat input from the evaporator fan averaged over the cycle time
qdefrostave heat input from the defrost heaters averaged over defrost cycle time
qcompave heat input from elevated exterior walls near the running compressor
Table 62 presents the overall cabinet load analysis results
50
Table 62 Overall Cabinet Loads
Load W Load Btuhr Total
qlD 550 1876 591
qedge 265 903 285
Qwall 49155 167 188 53
Qdoor 66155 2251 188 71
Qseal 25 85 27
Qmullon 88 300 94
Qtubl ngt 37 126 40
qmisc 116 395 124
Qfanave 46 157 49
Qdefrost ave 50 170 54
qcomoave 20 68 21
qtot 931 3174 100
Simulation Results
All loads are detennined experimentally with the exception oflsea1 and qtubeave The
values for qwall and qdoor are detennined from both experimental data and numerical
simulations Edge loss per unit length along fresh food perimeter is 29 Wm (30 Btuhrshy
ft) the loss per unit length along the freezer perimeter is 44 Wm (46 Btuhr-ft) and the
loss along the mullion section is 123 Wm (128 Btuhr-ft) with the heater on and 22 Wm
(23 Btuhr-ft) with anti-sweat heater off
The largest single load is the one-dimensional conduction through the walls and doors
The edge load comprises 285 of the total a significant portion The largest edge load is
due to the electric anti-sweat heater that is installed in the mullion section The smallest
edge load is due to the heat conduction through the fresh food and freezer door seals The
losses at the wall-side and door-side flange regions account for 53 and 71 of the total
load respectively These could be considered together since the pathway of heat transfer is
very similar If that were the case the sum of qwall and qdoor would be the second largest
contributor to the overall cabinet load The influence of an anti-sweat condenser tube is
reflected in the value of qtubeave Although this additional load is larger than qwall it must
be integrated over the refrigeration cycle timewhich is 50 of the cycle time for the test
unit The tube boosts the heat transfer along the wall flange by 76
51
To round out the cabinet load three miscellaneous loads are considered The evaporator
fan motor produces a heat load within the cabinet which is considered to be equal to the
power rating of the fan The automatic defrost feature is another thermal load that is
cyclical appearing about every ten to twelve hours of compressor runtime The fmalload
is due to the elevated exterior skin temperature near the compressor when it is running All
three of these loads are averaged over their cycle times for comparison with other quasishy
steady loads As a total qmisc represents 124 of the overall cabinet load
Opportunities to decrease the one-dimensionalload are available The emphasis has been to
develop super-insulations to be installed in the refrigerators Some being considered are
vacuum panels aerogels and vacuum packed powder insulations The disadvantages of
this improvement lies within the need to develop a cost-effective technique for fabricating
and installing such technologies compatible with high-volume manufacturing Also edge
losses and panel connection losses must be minimized due to the difficulty in making a
panel the size of refrigerator interiors Reliability of the seal and perfonnance of the outer
envelope need to be ensured over a long period of time ie the expected life of the
product
The possibilities of reducing the loads along the edge of the refrigerator aperture are
somewhat less apparent One method of reducing quasi-steady heat conduction along wall
and door flanges is to raise the inside cabinet wall temperature by minimizing interior film
surface heat transfer coefficients This could be accomplished by the use of low-emissivity
surfaces on the interior walls or on sections nearest the edges The need for an anti-sweat
device for the perimeter is also eliminated supplying a two-fold savings by reducing the
cabinet ioad and the system energy consumption The need for an electric mullion heater
might also be done away with by the same means The drawback again would be to make
such modifications acceptable and cost-effective for manufacture
The remaining miscellaneous loads provide some chance for improvement If the
efficiency of the fans is increased the energy use of the refrigerator can be reduced The
option of moving the fan motor outside the cabinet leads to other problems The motor
shaft must pierce the wall providing another path for heat leakage Also frost built-up on
the shaft would be a costly and difficult problem to eliminate If the compressor and
condenser were located near the top of the refrigerator they can operate more efficiently
Heat can be more readily convected away eliminating the need for the condenser fan
(Turiel and Heydari 1988) Frost fonnation in the freezer varies significantly depending
52
on the ambient conditions and the freezer usage The defrost cycle could be made more
energy efficient with the addition of adaptive controls All of these improvements would
require redesign of the product and the manufacturing process This is a very expensive
alternative which would need to be justified by the associated energy savings
53
7 SUMMARY OF CONCLUSIONS
The following is a list of the important findings produced from this study
(i) The edge loading accounts for a significant portion of the total cabinet load For the
test unit used in this study an 18 cubic foot top-mount refrigerator this load was
approximately 30 of the total load The load includes losses along the wall and door
flanges conduction through the door seal mullion loading with an electric anti-sweat
heater on and additional thennal input from an anti-sweat perimeter condenser tube
(ii) The presence of an electric anti-sweat mullion heater boosts the mullion loading by
a factor of approximately 5
(iii) The presence of an anti-sweat condenser tube around the perimeter of the refrigerator
increases the wall flange load by approximately 75
(iv) The presence of the door air damt reduces the temperature difference across the door
seal to 35 of the temperature difference between the interior and exterior
environments
(v) The hypothetical elimination of the additional load due to the electric anti-sweat
mullion heater reduces the edge loading to approximately 22 of the total cabinet
load
(vi) The hypothetical elimination of the load due to the anti-sweat condenser tube reduces
the edge loading to approximately 25 of the total cabinet load Ifboth anti-sweat
devices were not needed the edge loading would be further reduced to only 17 of
the total
(vii) During the course of this investigation it was concluded that the experimental and
numerical methods developed are applicable to most refrigeratorfreezers that are
produced today
t The portion of the door liner that extends into the cabinet along the wall
54
REFERENCES
Braswell A 1988 Impact of CFC Regulations on the Air Conditioning and Refrigeration Industry International Jow-nal ofRefrigeration Vol 11 No6 p 385
Cabot Corporation 1987 CAB-O-SIL Fumed Silica Properties and Functions Tuscola n pp 12-15
Clausing A M 1983 Natural Convection Correlations for Vertical Surfaces Including Influences of Variable Properties ASME Jow-nal ofHeat Transfer Vol 105 No 1 pp 138-143
Incropera FP and Dewitt DP 1985 Fundamentals ofHeat and Mass Transfer Second Edition John Wiley and Sons New York
Ingersoll LR Zobel OJ and Ingersoll AC 1954 Heat Conduction with Engineering and Geological Applications McGraw-Hill Book Company New York
Little AD Inc 1982 Refrigerator and Freezer Computer Model Users Guide Cambridge Massachusettes
Micropore International Ltd Microtherm Thermal Insulation Worcestershire England Section 1
Nix GH Lowery GW Vachon RI and Tanger GE 1967 Direct Determination of Thermal Diffusivity and Conductivity with a Refined Line-Source Technique Progress in Astronautics and Aeronautics (Vol 20) Thermophysics ofSpacecraft an Planetary Bodies Academic Press New York pp 865-878
Nix GH Vachon RI Lowery GW and McCurry TA 1968 The Line-Source Method Procedure and Iterative Scheme for Combined Determination of Conductivity and Diffusivity Thermal Conductivity Proceeding of8th Conference
Ozisik MN 1980 Heat Conduction Wiley-Interscience Publishing New York pp 486-487
Staley D 1992 Personal Communication Graduate Research Assistant University of Illinois Urbana
Turiel I Heydari A 1988 Analysis of Design Options to Improve the Efficiency of Refrigerator-Freezers and Freezers ASH RAE Transactions Vol 94 Part 2
Van der Held EFM and Van Drunen FG 1949 Physika Vol 15 No 10 p 865
White PM 1988 Heat and Mass TranSer Addison-Wesley Publishing Reading Mass pp 145-160
55
APPENDIX A FUMED SILICA INVESTIGATION
A ~ 1 Introduction
Fumed silica is a micro-porous powder comprised of submicron particles of amorphous
silica bonded together in a cellular structure Several grades of silica are available offering
a selection ofdifferent grain sizes and chemical treatments Fumed silica is commonly used
to provide thickening thixotropy suspension and other related properties in liquid
systems In dry systems it is used to promote free flow frictionizing and anti-blocking
properties Thus it is a versatile additive in materials such as inks coatings adhesives~
and silicon rubber (Cabot Corporation 1987)
The thermal insulating properties of this material have been somewhat less widely applied
however fumed silica as an insulation displays some interesting properties Fumed silica
insulations are commercially available and have become a more popular material for certain
specific applications In this section the results of an investigation of the thermal
properties of one type of fumed silica is presented
A2 Thermal Properties
As an insulator fumed silica uses the microporous principle to reduce thermal conduction
to the theoretically lowest possible levels (Micropore International Ltd 1988) Most
conventional insulations rely upon voids normally occupied bj alt aS the meanS ot
minimizing heat transfer through the material Therefore it is important to maintain these
voids for maximum insulation Fumed silica is comprised of tiny spheres with diameters
of the same order of magnitude as the mean free path of the molecules in the air
Therefore when these spheres are packed closely together gaseous conduction and
convection are minimized The cell size is sufficiently small to keep convective currents
from forming and to trap gas molecules to rebound elastically thereby not imparting their
energy to slower moving molecules In addition solid conduction is minimized by the fact
that silica is a material with intrinsically low thermal conductivity These unique properties
make fumed silica an attraCtive alternative to conventional insulations
56
A3 Experimental Method
Thennal conductivity and thennal diffusivity are the properties detennined from our
experimental study Many methods exist for establishing the thennal properties of a given
substance Both steady-state and transient procedures are available The hot-wire method
is a the transient procedure used in this study
The practical form of the hot-wire method is given by Van derHeldand Van Dronen
(1949) who used it to detennine conductivities of liquids Nix et al (1967) elaborated to
give a method for the simultaneous detennination of both thennal conductivity and thennal
diffusivity Therefore it is possible to detennine both conductivity and diffusivity by
passing a known amount ofcmrent through a heater wire embedded in the test material and
recording the temperature at a point on the wire and at a fixed point from the wire over the
period of the test From the temperature history of the point contiguous to the hot-wire the
conductivity can be detennined directly From the temperature history of the point at a
fixed distance from the hot-wire the diffusivity may be computed Both procedures are
outlined in the following section
A4 Theory
The temperature at any point in an infinite solid containing a line heat source of constantshy
rate is a function of the position time from initiation the thennal conductivity of the
material and the magnitude of the source This is shown mathematically by Ingersoll et aI
(1954) The cylindrical temperature field is expressed as
T=~l- exp-x2) dx (Al)21tk x
II
In series fonn
(A2)T=~[-amp-lnp+L-L+L_ ]21tk 2 21 4middot2 63
57
where
q = Heat input per unit length of wire [W1m]
k = Thennal conductivity of the material [Wm-K]
a = Thennal diffusivity of the material [m2s]
t = Elapsed time from heat liberation [s]
r = Radial distance from line-source [m]
Ce = Eulers constant (05772157 )
The temperature change between two times tl and t2 is accurate to better than one percent if
the value of ~ is less than 016 for a point very close to the line-source
(A3)
Equation (A3) is used in this case to detennine the thennal conductivity since the
diffusivity a and the radial distance T no longer appear in the relation Therefore
knowing the temperature at two different times during the test gives the conductivity
directly given that the value of ~ remains small This is achieved by choosing a point very
near if not contiguous to the hot-wire itself In our study a graphical method is used to
detennine the conductivity If the temperature versus the natural logarithm of the time is
plotted a straight line should be seen whose slope is equal to q4nk
Once the conductivity of the material is detennined the diffusivity can be found by the
method proposed by Nix et aI (1968) The temperature at a fixed and known distance
from the hot-wire must be monitored over the time period of the test Now since ~ gt 016
the diffusivity does not drop out of Equation (A2) Rewriting Equation (A3) as
(A4)
where
~2 ~4 ~6 ]r(~)= [ -~-ln~+---+-- (A5) 2 211 4middot2 6middot3
58
therefore (A6)
Using the temperature at the fixed location as an input Equation (A6) can be solved iteratively by means of Newton-Raphson technique to find the parameter ~ and thereby
yielding the thermal diffusivity a
AS Test Apparatus
Figure A1 is a sketch of the test apparatus used to collect thermal property data This
device provides a wide range of silica densities for packed tests Each half of the apparatus
is packed separately to the same density and then pressed together sandwiching the heater
wirethermocouple assembly between them
Remove bottom plate and press together with right half
Insert heater wirethermocouple assembl)
Remove bottom plate and press together with left half
Compact both halves to same density
Fig AI Fumed Silica Test Apparatus
Prior to loading the unpacked silica into the test cylinders the mass is carefully recorded
Each test cylinder has graduated marks to allow the volume of the sample to be computed
The density is then computed from the measured mass and volume At higher densities it
59
is sometimes necessary to load and compact several times Figure A2 is a schematic of the
heater wirethermocouple assembly and the entire test facility
Switch
Ammeter
Power Source
Cylindrical Test Section
Thermocouple for Conductivity
Data Acquisition System
Thermocouple for Diffusivity
Fig A2 Fumed Silica Test Facility Schematic
The heater wire used for all tests is 30 A WG nichrome wire with a nominal resistance of 2214 Wm Both thermocouples are type T 36 A WG Once the test sample is in place
the switch is closed allowing cUITent to pass through the heater wire The heat input per
unit length of the wire is determined from
(A7)
where q = Heat input per unit length of wire [Wm]
I = The input cUITent [Amps]
R = Heater wire resistance per unit length [Wm]
60
Knowing the heat input per unit length the temperature contiguous to the heater wire and
the temperature at a fixed distance from the heater wire over the duration of the test eqs
(A3) and (A6) can be solved This yields the conductivity and diffusivity respectively
A6 Results
All results presented in this section are from tests petfonned with a material sample donated
by Cabot Corporations Cab-O-Sil Division The silica is an untreated sample EH-5 with
a bulk density of 25 Ibsft3 and a nominal particle diameter of 70 angstroms Several tests
are petfonned at various densities The thermal conductivity is determined graphically as described above while the diffusivity is determined using a Fortran code to pe~orm the
Newton-Raphson iteration also outlined in Section A4
A total of seven different bulk densities are tested Each test consists of three runs at three
different power levels The temperature history is recorded for both thermocouples
Figure A3 is a plot of the temperature for the duration of a typical test for unpacked silica
70~--~----+----r----~-----~----+----r
10001
middot middot middot o 05 Ampsmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddot o 04 Ampsi ~ i
I i I I i oo~ct 60 IIJatr-T50
1 LL~40
1 ~ 1 010 1 ltgtom
JPi i30 i 0I1 o 03 Amps 1 I I
20~--~----+----r----~-----~----+----r
-10 o 10 20 30 40 50 60 70 Time (sec)
Fig A3 Time vs Temperature for Unpacked Run
61
To graphically detennine the thennal conductivity the temperatme data must be plotted
against the natural logarithm of time Figure A4 gives this plot along with the equations
that represent linear curve-fits to the straight portion of each curve
70~----~--------+------+--------~----~----~--------+-----~
60 ~ =l-LL-~--o T ~ 86839 ~ 1376 ~(t) I
50 ---f--H-deg--tfjtshy ~ T =11108 + 97346 m(t)
40 IT_oroJ~-
30 middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotImiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotsectmiddotmiddotmiddotmiddotmiddotImiddotmiddotmiddotmiddotmiddotmiddotmiddot~middotmiddotmiddotmiddot109~~Q9 T= 18431~ + 493 ~(t) 0
~ e i i i
20~----~--------+------+--------~---------~~----+------r
05 1 15 2 25 3 35 4 45 In (time)
Fig A4 Natural Log Time vs Temperature for Unpacked Run
All three curves should yield the same conductivity for the sample The conductivity is
detennined from the following relation
k= 12R (A8)4n(slope)
Table AI gives the average conductivity for each density level This is the average for the
three input cmrents used These results are also shown graphically in Figure A5
62
Table AI A verage Fumed Silica Conductivity for Various Bulk Densities
est
1
2
3
4
5
6
7
0024
0023
0022 -~ ct 0021
~ e 002
~
0019
0018
0017
i
~i
I I I I Imiddotmiddotmiddot_middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotimiddot_middotmiddot middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotimiddot-middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot
1i111
~ ~ iii
_I_1_1_1
I I I I I middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot middotmiddotmiddotmiddotmiddotmiddotmiddotfmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddot -r-t-o-rldegoo---shy
25 3 35 4 45 5 55
Density (lbsff)
Fig AS Conductivity vs Bulk Density
From the temperature data collected from the second thennocouple the thennal diffusivity
is computed (see Section A4) This thennocouple lies 3 mm (0118 in) from the heater
63
wire The output from the diffusivity iteration is provided in Table A2 A graphical
representation is given in Figure A6
Table A2 Average Fumed Silica Diffusivity for Various Bulk Densities
Test
Average Diffusivity m2s (ft2Jhr)
1 210 x 10-7 (000813)
2 166 x 10-7 (000643)
3 159 x 10-7 (000616)
4 155 x 10-7 (000600)
5 153 x 10-7 (000592)
6 No Data Available
7 151 x 10-7 (000585)
00085 -+----+-----f----+----+----+--_+_
I
middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1 ~0008
I I I I ~
I middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotfmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot Tmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot ~ 00075
~-shyf i ~ ~ ~ i ++middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotfmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot0007 i iii
~ rn ~ ~ i i~
(jj bullbullbullbullbullbull1bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullJLbullbullbullbullbullbullbullbullbullbullj ~ 00065o ~ middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot0006
I I I 00055 -+----+-----f----+----+----f--_+_
25 3 35 4 45 5 55
Density (lbsff)
Fig AS Diffusivity vs Bulk Density
64
A7 Conclusions
The primary conclusion from this experimental study is the fact that the thennal insulating
properties of fumed silica powder increase as the bulk density of the material increases
Although this study presents a limited range of density values the trends that were
expected are seen to be true The conductivity values are expected to reach and even
surpass those of CFC-blown foams that are used in household refrigerators Further
testing is needed to provide data that supports this expectation In addition testing in this
study was strictly limited to a single variety of silica This particular type of silica is not
necessarily the best candidate for thermal insulation applications Silica powders are by
nature hydroscopic This affinity for water has adverse effects on its thermal insulating
properties However silica powders are now produced with a special treatment which
transforms the material into a hydrophobic material Therefore if these new materials
maintain the thermal properties and density trends of the hydroscopic type they become
even more preferred insulators Once again data needs to be obtained to support this
notion Fumed silica offers a competitive alternative to the existing CFC-blown foams
without the obvious environmental drawbacks It is completely inert recyclable and
reusable It also competes well when comparing cost values CFC-blown foams are
between 003 - 007 $ft2_R-Value whereas fumed silica powder are between 005 -025
$ft2-R-Value The discrepancies are close enough to merit true consideration
AS Thermal Diffusivity Newton-Raphson Iteration Source Code
program difsivty implicit none double precision condqtime(lOO)temp(lOO)guessradiusalpha
+ dif(lOO)sumavedifgcurrentmasslengthpi + density integer nikrun OPEN (2file=Oiffusivityoutlposition=rewind) OPEN (3file=Oiffusivityinposition=rewind) OPEN (4file=Oiffusivityout2position=rewind)
print Enter input current in amps readcurrent printEnter calculated conductivity in Wm K readcond print Enter thermocouple distance in meters readradius print Enter mass of sample in grams readmass print Enter compacted length of sample in em readlength print Enter number of timetemperature data points
65
c
readn 5 print enter initial quess for beta
readquess c
pi=31415927 q=currentcurrent2214 density=(mass1000)laquopi4)(003844)(lenqth100raquo
c c check to see if converqence will occur c print Enter data point l c print (time and temp with a blank separatinq the two) c readtime(1)temp(1) c call diffus(condqtime(1)temp(1)quessradiusalphaq) c printinitial q=q c if (abs(q) qt 05) then c qoto5 c endif c
do 10 i=1n read(3) time(i)temp(i)
10 continue c
print print Input Current= current print write(2) Input Current= current write (2 )
c sum=OO do 20 k=1n call diffus(condqtime(k)temp(k)quessradiusalphaq) print Diffusivity for data pointk =alpha write(2) Diffusivity for data pointk =alpha write(4) alpha dif(k)=alpha sum=sum+dif(k)
20 continue c
avedif=sumn c
print print print INPUT print Conductivity=cond Wm K print Heater Input=q Wm print Thermocouple Distance=radius m print- print OUTPUT print Sample Density=density kqm3 print Averaqe Diffusivity=avedifmiddot m2s
c write(2) write(2) INPUT write(2) Conductivity=cond Wm K write(2) Heater Input=q Wm write(2) Thermocouple Distance=radius m write (2 ) write(2) OUTPUT write(2) Sample Density=density kqm3 write(2) Averaqe Diffusivity=avedif m2s
c c
pause stop
66
end
subroutine diffus(condqtimetempguessradiusalphag) implicit none double precision condqtimetempbeta(100)radius
+ f1f2f1pf2ptempf2tempf2pggppialphaCe + signfactol integer jkmn
c Ce=5772157 pi=31415927 beta (1) =guess tol=l j=l
c c begin Newton-Raphson iteration to find beta and ultimately alpha c
while (tol gt 0001) c print betaj =beta(j)
f1=-Ce20 - log(beta(j)) flp=-l Obeta (j) f2=00 f2p=00
c c start loop to compute the summations for f2 and f2 prime
do 10 k=2162 m=k2
c this loop gives the factorial for the kth term fac=10 do 5 n=lm
fac=facn 5 continue
sign=(-1)laquok+2)2) tempf2=laquobeta(j)k)sign)(kfac) tempf2p=laquobeta(j)(k-1))sign)fac f2=f2+tempf2 f2p=f2p+tempf2p
10 continue
c c compute the value of G and G which are both functions of beta c these will be used to update beta in the Newton-Raphson iteration c where beta(n+1)= beta(n)- GG
g=laquo20picondtemp)q)-(f1+f2) gp=- (flp+f2p)
c print g=g c here we check to see if the convergence criterion suggested c by Nix is met for the initial beta chosen if not we must jump out of loop c if (j eq 1) then c if (abs(g) qt 05) then c printconvergence not satisfied c printtry a s~aller guess for beta c return c endif c endif c c update the value of beta and compute a tolerance value c that will be used to check for convergence
beta(j+1)=beta(j)-(ggp) tol=abs(beta(j+1)-beta(j))
67
j=j+1 c protect against infinite looping
if (j eq 100) then goto 101
endif repeat
c c if the iteration converges then compute the value for diffusivity
alpha=(10(40timeraquo(radiusbeta(jraquo2
c c
101 return
68
APPENDIX B ONE-DIMENSIONAL SIMULATION SOURCE CODE AND OUTPUT
B1 Source Code
CPROGRAM FrigWall--Steady-State Heat Conduction with Convective and CRadiative Heat Transfer from interior and exterior surfaces C Programmed by AM CLAUSING
LOGICAL SI DIMENSION RA(2)XNU(2)R(2)H(2)HR(2)TF(2)TW(2)DT(2) COMMON AXLWXLC(2)HC(2)T(2)XKWBETANMAXSIE(2)SIGMA
CDetermine- direction of output read and print input data NCASE=l
1 CALL DATAIN(NCASEIUOUT) NCASE=NCASE+1 QOLD=O TW(1)=T(1)+1(T(2)-T(1raquo TW(2)=T(2)-1(T(2)-T(1raquo
CCalculate wall resistance RW=XLWXKWA DO 3 N=lNMAX DO S J=12
CCalculate the radiative equivalent heat transfer coefficients HR(J)=SIGMAE(J)(T(J)2+TW(J)2)(T(J)+TW(Jraquo
C Calculate the film temperatures TF(J)=(T(J)+TW(Jraquo2
CCalculate the convective heat transfer coefficients CALL GASPT(lTF(J)RHOXMUXKCPGRBPRIER) DT(J)=ABS(TW(J)-T(Jraquo RA(J)=PRGRBXLC(J)3DT(J) IF(RA(J) LT1E9) THEN
XNU(J)=0S2RA(J)2S ELSE
XNU(J)=09RA(J) 3333 ENDIF H(J)=XNU(J)XKXLC(J) IF(HC(J) NE O) H(J)=HC(J)
CCalculate surface resistances R(J)=l(H(J)+HR(JraquoA
S CONTINUE CCalc~late total resistance heat flow rate and surface temperatures
RT=R(1)+R(2)+RW Q=(T(2)-T(1raquoRT TW(l)=T(l)+QR(l) TW(2)=T(2)-QR(2)
CCheck for convergence If solution has converged exit loop ERRQ=ABS(Q-QOLD)100Q QOLD=Q IF(ERRQLT OS) GOTO 7
3 CONTINUE 7 WRITE (IUOUT 101) Q ERRQ (H (J) HR (J) RA (J) XNU (J) TW (J) DT (J) R (J) RT
2 J=l2) 101 FORMAT( Q =F61 W10XERRQ =FS2 T12 hconvT22hradT33
2 RaT44NuTS2 TsurT62 DeltaTT72RRtotT10 [Wm2-KjT20 2 [Wm2-KjTS3 [KjT63 [Kj InsideF72F92E133F91 2 F101F91F113 OutsideF62F92E133F91F101F91F113) DO 9 J=l2 IF(HC(J) NE bull O) WRITE (IUOUT 103) J
9 CONTINUE 103 FORMAT( NOTE hconv(I1 ) was specified not calculated)
GOTO 1 END
69
C SUBROUTINE DATAIN(NCASEIUOUT) LOGICAL SI COMMON AXLWXLC(2)HC(2)T(2)XKWBETANMAXSIE(2)SIGMA DATA AXLWXKWXLCHCTENMAXSIGMA2990360245315 2 20277297 959510567E-8
CDefinition of NAM NAMELIST NAMAXLWXKWXLCHCETNMAXBETASI CHARACTER FNAME60CDATE9CTIME8 PARAMETER (IUIN=7)
CIF First Case Open Files Write Program Description and Date IF (NCASEEQ 1) THEN
WRITE (6 100) 100 FORMAT( TYPE NAME OF INPUT DATA FILE)
READ( (A) ) FNAME COpen input and output files
OPEN (7FILE=FNAME) REWIND 7
C OPEN (10FILE=Plots-FNAME) C WRITE(6122) Plots-FNAME C122 FORMAT( COMMA DELIMITED PLOTTING FILE IS A)
WRITE(6118) 118 FORMAT (T10 DIRECT OUTPUT TOT20 SCREENT36 Type 6
2 T20 OUTPUT FILET36 Type 8T20 PRINTERT36 Type 9) READ() IUOUT IF(IUOUTEQ8) THEN OPEN (8FILE=Answers-FNAME) WRITE(6120) Answers-FNAME
120 FORMAT( OUTPUT WILL BE WRITTEN IN FILE A) ENDIF CALL DATE(CDATE) CALL TIME(CTIME)
CWrite Program Description and Date WRITE(IUOUT102)CDATECTIME
102 FORMAT( Program FrigWallT60 Date A10 Version 8 August 1991T60 2 Time A9 Programmed by AMClausing) ENDIF
CRead and Write Input Data READ(IUINNAMEND=999) WRITE (IUOUT 104) NCASETXLCEXLWXKWA
104 FORMAT ( CASE NUMBER 12 2 Ambient Temperatures IK] InsideF616X OutsideF61 2 Characteristic Lengths 1m] InsideF626X OutsideF62 2 Surface Emissivities8X InsideF626XOutsideF62 Wall
Thickness 2 F63 mT27 ConductivityF63 Wm-K2x AreaF52 m2) RETURN
999 WRITE (IUOUT 199) 199 FORMAT ( ALL INPUT DATA HAS BEEN PROCESSED) 991 CLOSE(10)
IF(IUOUTEQ 8) CLOSE(8) STOP END
C SUBROUTINE GASPT(NGASTRHOXMUXKCPGRBPRIER)
C PROGRAMMED BY A M CLAUSING VERSION APRIL 1982 C PROPERTIES OF GASES IN SI UNITS(TGTO) OR ENGLISH UNITS(TLT O) C FUNCTIONAL REPRESENTATIONS USED ARE OF THE FORM Y=ATB C ARRAYS A AND B CONTAIN THE RESPECTIVE CONSTANTS C INPUT C NGAS - NGAS=l IS AIR NGAS=2 IS NITROGEN C T ---- ABSOLUTE TEMP (K) OR NEGATIVE OF ABSOLUTE TEMP (R) C OUTPUT C RHO -- DENSITY (KGM3) OR (LBMFT3)
70
C XMU -- VISCOSITY (KGM-S) OR (LBMFT-S) C XK --- THERMAL CONDUCTIVITY (WM-K) OR (BTUHR-FT-R) C CP --- SPECIFIC HEAT (JKG-K) OR (BTULBM-R) C GRB -- GBETAXNU2 (1M3-K) OR (1FT3-R) C PR --- PRANDTL NUMBER (DIMENSIONLESS) C IER -- ERROR PARAMETER C INFORMATIVE ERRORS C IER=l --- GAS NUMBER DOES NOT EXIST GAS IS ASSUMED TO BE AIR C IER=2 --- TEMPERATURE OUT OF RANGE OF PROPERTY SUBROUTINE C RESTRICTIONS C NGAS -- MUST BE l(AIR) OR 2 (NITROGEN) C T ----- T MUST LIE BETWEEN 150K AND 2100K FOR AIR AND BETWEEN C 83K AND 450K FOR NITROGEN RANGES ARE SPECIFIED WITH ARRAY R C
DIMENSION A(152)B(152)R(32) DATA A36411764E-61423E-399084178E20123 235064914E-62494E-329944985E195930 3 432491E-81239E-415534379E201137 4351618E-6221E-31031408E2084130 DATA B-1005814913800316-4639-09685 2 -999642981521962-4284023930 3 -10469389466-079-5102-0872 4 -10058058 834500239-4636-0265230 DATA R150400210083160450 IER=O IFlaquoNGASGTO) AND(NGASLT3raquo GO TO 1 IER=l NGAS=l
1 1=1 TP=T IF(TLT bullbull O) TP=-T18 IFlaquoTPLTR(lNGASraquo OR (TPGTR(3NGASraquo) IER=2 IF(TPGTR(2NGASraquoI=7 RHO=A(INGAS)TPB(INGAS) XMU=A(I+1NGAS)TPB(I+1NGAS) XK=A(I+2NGAS)TPB(I+2NGAS) CP=A(I+3NGAS)TPB(I+3NGAS) GRB=A(I+4NGAS)TPB(I+4NGAS) PR=A(I+5NGAS)TPB(I+5NGAS) IF(TGT O)RETURN RHO=RHO1602 XMU=XMUl 488 XK=XKl 731 CP=CP4187 GRB=GRB6357 RETURN END
B2 Output
Program FrigWal1 Version 8 August 1991 Programmed by AMClausing
Date Time
05-MAR-92 200227
CASE NUMBER 1 - Fresh Food Walls
Ambient Temperatures IK] Inside 2770 Outside 2940 Characteristic Lengths 1m] Inside 030 Outside 150 Surface Emissivities Inside 095 Outside 095
71
Wall Thickness 0045 m Conductivity 0027 Wm-K Area 242 m2
Q = 209 W ERRQ = 002
hconv [Wm2-K]
Inside 1 98 Outside 130
hrad [Wm2-K] 461 544
Ra
0488E+07 0459E+09
Nu
244 761
Tsur [K]
2783 2927
DeltaT [K] 13 13
RRtot
0077 0075
CASE NUMBER 2 - Fresh Food Door
Ambient Temperatures [K] Inside 2770 Outside 2940 Characteristic Lengths [m] Inside 030 Outside 150 Surface Emissivities Inside 095 Outside 095 Wall Thickness 0040 m Conductivity 0040 Wm-K Area 089 m2
Q = 117 W ERRQ = 001
hconv [Wm2-K]
Inside 218 Outside 144
hrad [Wm2-K] 463 542
Ra
0714E+07 0690E+09
Nu
269 843
Tsur [K]
2789 2921
DeltaT [K]
19 19
RRtot
0114 0113
CASE NUMBER 3 - Freezer Walls
Ambient Temperatures [K] Inside Characteristic Lengths [m] Inside Surface Emissivities Inside
2630 030 095
Wall Thickness 0056 m Conductivity 0027
Outside Outside Outside
2940 150 095
Wm-K Area 110 m2
Q = 14 3 W ERRQ = 003
hconv [Wm2-K]
Inside 226 Outside 143
hrad [Wm2-K] 397 542
Ra
0990E+07 0684E+09
Nu
292 841
Tsur [K]
2651 2921
DeltaT [K]
21 19
RRtot
0067 0061
CASE NUMBER 4 - Freezer Door
Ambient Temperatures [K] Inside 2630 Outside 2940 Characteristic Lengths [m] Inside 030 Outside 150 Surface Emissivities Inside 095 Outside 095 Wall Thickness 0040 m Conductivity 0040 Wm-K Area 034 m2
Q = 81 W ERRQ 002
hconv [Wm2-K]
Inside 259 Outside 1 64
hrad [Wm2-K] 400 538
Ra
0169E+08 0124E+10
Nu
333 967
Tsur [K]
2666 2906
DeltaT [K] 36 34
RRtot
0117 0110
72
__ ___
APPENDIX C TEST REFRIGERATOR DESCRIPTION
The test refrigerator is a White-Westinghouse model RT193MCWO 186 cubic foot
capacity top-mounted unit It is equipped with full automatic defrost The cycle time for
this unit is approximately 50 The unit also has two anti-sweat devices An electric
heater is located in the mullion region to prevent frosting between the freezer and the fresh
food compartments Also a condenser tube runs around the entire outside perimeter of the
unit embedded beneath the steel all flange Figure C1 illustrates these features
~1-- 0787 m (31)__
~ r_----------------------
1581 m
Fig CI Location of Anti-sweat Devices and Overall Dimensions of Test Refrigerator
73
Under test conditions the refrigerator and freezer are filled with milk containers full of
water These containers provide sufficient thennal mass to minimize temperature
fluctuations dming experimental runs Twenty gallons are present in the fresh food
compartment and 6 gallons are in the freezer
Figures C2 through C5 give the detailed dimensions of the fresh food compartment and
the freezer All dimensions are in millimeters and are obtained directly from the unit
Dimensions are estimated to be accurate to within plusmn 3 mm
697
762
1
305
717
Fig C2 Fresh Food Compartment Interior Dimensions
74
1127
Fig C3 Fresh Food Door
75
675
381
Fig C4 Freezer Interior Dimensions
432
Fig CS Freezer Door
76
APPENDIX D DATA ACQUISITION AND CONTROL SYSTEM
Corresponding with the construction of the experimental apparatus was the purchase and
assembly of a data acquisition and control system The system itself was designed to meet
the needs of a variety of experiments and is therefore a very flexible system
The system consists of six DC power supplies a data acquisition chassis a computer a
rack ofdigital relays and a variety of analog and digital inputs and outputs A data
acquisition and control software package orchestrates the interactions between these
components and regulates outgoing signals as well as providing data storage
External signals enter the system through a Keithley 500P data acquisition chassis These
signals consist of voltage and current measurements from the power supplies as well as
thermocouple voltages At present a total of ninety-six thermocouple inputs are available
with an optimal resolution of +0012 degrees C The addition of more thermocouple input
boards could expand the capability to 128 inputs Also special boards can be installed to
allow strain gauge thermistor digital or other standard data acquisition functions The
Keithley chassis can contain a total of nine interface boards and its l~bit AID conversion
allows for very high resolution
The six DC power supplies consist of two Hewlett Packard and four Sorensens with a
combined power of 7560 watts The Sorensens are rated at 0-150 volts at a maximum of
12 amps while the Hewlett Packards produce 0-60 volts at a maximum of 3 amps All of
the power supplies are computer-controlled however the Sorensens may be operated
manually ifdesired Voltage measurements from the power supplies are fed into the
Keithley acquisition chassis and are then routed to the computer A voltage from the
computer is buffered and fed into the control circuits of the power supplies This voltage
completes the loop and controls the output voltage of the power supplies The software is
responsible for reading the output voltage of the power supplies comparing it with the
intended setpoint and adjusting the control voltage as needed This arrangement allows the
user to vary the output voltage of the power supplies from within a program Computershy
controlled safety relays are in place to disconnect the power supplies should they stray too
far from the intended voltage setpoint Fig D1 displays the system
77
Thermocouple and Voltage Inputs
r
Computer Data Acquisition Chasis Intaface
00 Voltage and 1 r Current
Measurement
Computer
I I
Analog Control Signal
Digital Oulput Signals 5 6
Power Supply 4 Relay Rack
Power Supply 3 00000001 Power Supply 2
Buffered Analog100000001 Power Supply 1 Control Signal
1 2 3 4 5 6 - I
I00 00 )0 po po po
Ir Digital Outputs
Analog Outputs
Fig DI Data Acquisition and Control System
78
APPENDIX E EXPERIMENTAL RAW DATA AND PLOTS
E1 Temperature Profile Plots From Fixed Thermocouples
In this appendix the remaining tests for the fixed thennocouple testing presented in Section
41 are provided Figures E1 and E2 give the results from the fresh food compartment
and Figures E3 and E4 give the results from the freezer Notice the outdoor and interior
ambient temperatures are not the same as the two tests presented in Section 41
191
Run 2 ttl ~ i i
middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot
middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot-imiddotmiddot
TWall
middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotlmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot
-
Outdoor Ambient =210 degC Fresh Food Ambient =375 degC
-] _ Door ProfUe i -il- 0 Wall Profile
i 19
$-- - Tdo = 19078 - 001326x
l~l ~~i 189 i i a m
0 i -m-
i 188 middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot
187 ~ middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot 5 = 18989 - O02024x 1
F 186
~bullbullbullbullbullbullbullmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot185 i i
184 0 5 10 15 20 25
x (mm)
Fig E1 Steel Skin Temperature Plot for Fresh Food Compartment (Run 2)
79
191
19
189
a ~
i 188
187
5F
186
185
184 0
Run 3 I --D - Door Profile
middotmiddotmiddotmiddotmiddotmiddotmiddotmiddot-middotmiddotmiddotmiddot~middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotimiddotmiddot-middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddot 0 Wall Profile
i - i - - Tdo =19053 - 001384x or
=c-=r=-~-= 1 11=
~ n - 189S 001998 --t-shy-~~-
5 10 15 20 25
x (mm)
Fig E2 Steel Skin Temperature Plot for Fresh Food Compartment
186
184
182
- ~- 18
178
~ 176
174
172 0
(Run 3)
Run 2 l --0 - Door Profile
middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot~middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotdrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotf 0 Wall Profile - 1- - middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot--m
- - T =18544 - 002398x i - i door rb
~i
i bullbullbulli _ bull imiddot
~ I TWall =18182 - 003542x tmiddotmiddotmiddotmiddot middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotlmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot
~ n~l l
5 10 15 20 25
x (mm)
Fig E3 Steel Skin Temperature Plot for Freezer (Run 2)
80
--a 0
I5F
186
184
182
18
178
176
174
172
Run 3 I --0 - Door Profile
middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotCmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotl 0 ~a1l Profile
ttl __ OJ 1 1 middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotfmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotlmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot -shy - Td = 18411 - 002272x ibullbullbullbullbullbullbull-bullbullbullbullbullbullbullbullbulli
oor ~
rp bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbull bull 11_1
I I middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotimiddotmiddotmiddotmiddot middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotImiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot
~ _l
Outdoor Ambient =208 degc Freezer Ambient = -93 degc
0 5 10 15 20 25
x (mm)
Fig E4 Steel Skin Temperature Plot for Freezer (Run 3)
E2 Thermopile Data Reduction
The data from the thennopile tests consist of an output voltage (mV) measured with a
Keithley multimeter which has a resolution of 1 m V The procedure required to translate
this voltage into a temperature difference follows
1 Read the output voltage in millivolts
2 Detennine the average skin temperature from fixed thennocouple data
3 Use the reference table and the average skin temperature to determine the conversion factor in Vrc
4 Convert to temperature difference as follows
1T = ____o_utpu_t_vo_l_tag-e___
ofjunctions x conversion factor
81
Table EI Thermopile Raw Data
ffOutput fzOutput ff Ave Skin Temp fz Ave Skin Temp mV mV CC CC
Roo wall door wall door wall door wall door
1 0052 0048 0045 0050 189 191 177 183
2 0054 0052 0046 0048 187 189 176 182
3 0056 0053 0046 0051 186 188 175 181 ff Conv Factor fz Conv Factor ff AT fzAT
Ilvrc Ilvre CC CC
Roo wall door wall door wall door wall door
1 40165 40181 40067 40116 026 024 037 041
2 40148 40165 40058 40107 027 026 038 040
3 40140 40157 40050 40099 027 026 038 040
Average Temperature Difference 0267 0377 0253 0403
from Thermocouple Reference Tables Based on the IPTS-68 US Dept of Commerce
E3 Experimental Determination of qwall and qdoor Details
The four heat fluxes are calculated using
-k M (El)q - m Ax
For 05 carbon cold rolled steel km =540 Wm K (312 Btuhr-ft-OF) Also Ax = OOlm (039 in) for all computations
0267degC 2 qwallff = 54 Wm-K 001 m = 14418 Wm
_ 0377 degc _ 2 qwallfz - 54 Wm-K 001 m - 20358 Wm
0~3~ 2 qdoorff =54 Wm-K 001 m =13662 Wm
82
0403degC 2 qdoorfz = 54 Wm-K 001 m = 21762 Wm
Compute the heat transfer rate according to Equation (B2)
q =qA=qhP (B2)
Where A is the cross sectional area of the steel casing that is perpendicular to the direction
of heat flow The area is the product of the steel skin thickness b and the total perimeter of
the compartment opening which is exposed to the room environment P Perimeter
definitions
Pwallff = llm + 076m +llm = 296 m
roJ D Pwallfz =O4lm + 076m + O4lm =l58 m
I ] I ~I Pdoorf( = llm + 076m + llm + 076m = 372 m
Pdoorfz =076m + O4lm + 076m + 041m =234 m
83
qwallff =(14418 Wm2)(65e-4 m)(296 m) =277 W
qwallfz =(20358 Wm2)(65e-4 m)(158 m) =209 W
qdoorff =(13662 Wm2)(65e-4 m)(372 m) =330 W
qdoorfz =(21762 Wm2)(65e-4 m)(234 m) =331 W
E4 Temperature Profile Plots From Mullion Data (Heater oro
The following plots are from the remaining runs for the mullion analysis presented in
Section 45 All data is taken from the exact center of the mullion
131
13 middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot-tmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotjmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotlmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot9middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotlmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot6middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddot T 11 f =12383 + 0019929x iii mu z
129 ~ middotImiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot[middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddota ~
i 128 middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot4middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot-j-middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotfmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotfmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot
127e ~
126 ~~~=H~~-~=HmiddotrI~ ++~11 Room Ambient =2250 degC125
1 1 i Fresh Ambient =515 degC iii i i Freezer Ambient =-603 degC
124
1 10
Fig ES Mullion Temperature Profile Run 2 (Heater Off)
Run 2
2 3 4 5 6 7 8 9
TIC
84
146
145
a 144 ~
i 143
5 ~ 142
141
Run 3 9 0
---r-r--deg-r-ideg-t-9--rshyiii ltD T 11 ff = 15173 - OOI71x mu bull
middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotfmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotImiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot6middotmiddot
1Tmull~fz =14062 + J0158211x JLt 1
Q 1 1 1 middotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1-middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddoti-middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotimiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotoot-middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot-I-bullbullbull~bullbullbullbullbullbullbullbullbullbullbull
iii middotiiimiddot-j Room
1Am~t = 21~1 degC
iii i 1 Fresh Ambient = 563 degC 1 1 1 1 1 Freezer Ambient = -153 degC
14~---+--~----r---+---~---+--~----r---+-
1 2 3 4 5 6 7 8 9
TIC I
Fig E6 Mullion Temperature Profile Run 3 (Heater Off)
127
126
125 a ~
i 124
123 e ~
122
121
12
1
Fig E7
i i CD middotmiddotmiddotmiddot----middotmiddot-r--middot---middotmiddotmiddotmiddotmiddotmiddot-lmiddot--------middotmiddotmiddotmiddotl-middotmiddot---middotmiddotmiddotmiddot---r---middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1middotmiddotmiddotmiddotmiddot---middotmiddot---middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot-r----middot1__ _-
I I I T mulIff = 1321 - 001532x middotmiddotmiddotmiddot------middott--------------tmiddotmiddot----middot----middotmiddot-1------middotmiddotmiddotmiddotmiddotmiddot---jmiddot-----middotmiddotmiddotmiddotmiddotmiddotmiddotmiddot-lmiddotmiddotmiddot---middotmiddotmiddot-----tmiddotmiddotmiddotmiddotmiddot--middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddot-----middotmiddotmiddot6middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot
I cent I I I I -~~~~-ro-Tr-
r-middotmiddotmiddotmiddotrTTr-middotrmiddotrmiddotrmiddot middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddott middotmiddotmiddottmiddotmiddot1middotmiddotbullbullbullbull fmiddotbullbullbullbullbullbullbullmiddot-fbullbullbullbullbullbullbullmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot
II Room Ambil =21~3 degC iii i i Fresh Ambient =551 degc iii i i Freezer Ambient = -681 degC
2 3 4 5 6 7 8 9 10
TIC I
Mullion Temperature Profile Run 4 (Heater Off)
85
10
111
iii i i 11
Fttul5
T mu
=J=~[rr~tl=rI=109
a ~ 108 -t-t-t-i~FFl~i~~
+-0amp_- -+_bullbullbullbullbullbullbullbull+ - bullbullbull 107 11 f ~ 10325 + 0021893x 1 1 1 ji
5 bull Z iii
------~-~-----~---i --L--l ---_l__ ---L-----_shy106 ~
105 -t---i--+-+-+-middot++-I-shyL1LLL Room Ambient = 2177 C104 iii i i Fresh Ambient =448 degC
Freezer Ambient = -644 degC 103
1 2 3 4 5 6 7 8 9 10
TIC
Fig E8 Mullion Temperature Profile Run 5 (Heater Off)
86
34
33 1 1 1 1 1 1 1 1------I---------middotmiddot--+middotmiddotmiddotmiddot------middottmiddot-------middotmiddotmiddotmiddottmiddot----------middotmiddotmiddot---middot---middot----tmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot---middotmiddott--middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot(middotmiddotmiddotmiddotmiddot--
32 11 f =1 2859 ~ OI~X j
Till ff =133013 j - 007124x mu
31
a ~ 30
i 5 ~
29
28
27
26
Tmullfz = 26944 + 014842x
mu t-tr l
25 middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotjmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotjmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotlmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1middot ~ u~ ~it
24 lllti1 ~ i i ~ i
0 Lower Limit
23
0 1 2 3 4 5 6 7 8 9 10
ES Temperature Profile Plots From Mullion Data (Heater On)
The following are the remaining plots from the mullion heater analysis presented in Section
46
TIC I
Fig E9 Mullion Temperature Profile Run 2 (CenterHeater On)
Run 2
T muz
1
87
l----+
29
middotmiddotmiddotgtmiddotmiddoti middot 0 upper Limit 28 Run 1
I
middotmiddotI o
Tmullfz
T muo
LL~4cb 0 Lower Limit27
middot~+ImiddotmiddotmiddotImiddotmiddotmiddottr9middotdJmiddotmiddotmiddotmiddot 26
t T = 29465 008022xmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddot1middotmiddotmiddotmiddotTmiddotmiddotmiddotmiddot[middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1middot mullffa 25~
i 24 =24837+ 013186x middotlmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot+middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotimiddotmiddotmiddotmiddotmiddotmiddotmiddotlmiddotmiddotmiddotmiddotmiddotmiddot iii i i
i _ Jbullbullbullbullbullbullbullbullbullbullbullbullbulli l _l ii 23
e 22~ 21 +I~=tt=l=fit
L~LLL Tm~llff = 23856 005858x20 11 f = 1803 + 02243x z -rmiddotmiddotmiddotmiddot1middot middotmiddot middotmiddot 1middotmiddotmiddotmiddotmiddotTmiddotmiddot middot-rmiddot19
18
0 1 2 3 4 5 6 7 8 9 10
TIC
35
34
33
32
a ~ 31
I ~
30
29
28
27
26
25
24
Fig EI0
---bull---i----bullbullmiddotmiddotmiddotmiddot--~--------middotmiddot-+------ j bullbullbullbull ---bullbullbullbull -i--__---
T 11 f =30063 + OI~x 1 T i 134 196 i
0068 1 38
muz tmiddotmiddot Ilff=middot bull x ltP lt1gt mu
=t=H=t+t=R=t= F-6~I-i~E
Tmullfz = 28103 + 014486x 1middot++middot1middot1
middotmiddotmiddot--middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotimiddotmiddotmiddotmiddotmiddotmiddotmiddot-middotmiddotmiddotmiddotmiddot+middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotbullbullmiddotmiddotmiddot-middotmiddotimiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot~middotmiddot
111111 0 Upper Limit iii iii 0 Lower Limit
0 1 2 3 4 5 6 7 8 9 10
TIC
Mullion Temperature Profile Run 3 (CenterHeater On)
Fig Ell Mullion Temperature Profile Run 1 (LeftHeater On)
88
a
29
28
27
26
25~
i 24
23 e
22~ 21
20
19
18
Fig E12
i l middot middotmiddotmiddotmiddotlmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot+ 0 Upper Limit T 11 f =24474 + 011288x i imu bull z o Lower Limit
=tplusmntplusmnfrplusmnplusmnplusmn ~ I I I I Tmull ff ~ 28793 - o0784x
middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddott----middot------middotmiddotimiddot----middot-middotmiddot--middot-~-middotmiddotmiddot--middot----middotmiddot)middot
=ii=t=1=P-Ltplusmnt iii i T = 25599 - 00689xIfmiddotTTTmiddotmiddotrmiddot ~Ullff iii
T l1f =20552 + 01676x i~~imiddotimiddotmiddot
==~LL L LLLLL i i 1 ~ 1 ~
0 1 2 3 4 5 6 7 8 9 10
TIC I
Mullion Temperature Profile Run 2 (LeftlHeater On)
33 iii i i
-middot--middot(---middotmiddot--middotmiddot--middotmiddot+---middot-middotmiddotmiddotmiddot-middotmiddotmiddot~-middot--middot-------middoti---middot------~ o Upper Limit 32 Run 3
t bullbullbull +
Tm~llfz
T mu
1 1 1 1 1 o Lower Limit ~~31
=2713 ~ 0113~x j11Li30
a T ulff =30658 - 006506x 29~
IktlJ2~Li 28
27 e
26 =l=tt=tmiddotmiddottmiddott+~middot+=t=~ middotmiddot jmiddotjmiddottmiddottmiddotjmiddot T = 28288 - 00603x
iii i mullff 24
25
middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotQmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot+middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot~middotmiddotmiddot middotmiddotmiddotmiddotmiddotmiddotmiddotmiddot~middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot+middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot 11 fz = 2377 ~ 01788x IL11123 i i
22
0 1 2 3 4 5 6 7 8 9 10
TIC I
Fig E13 Mullion Temperature Profile Run 3 (LeftHeater On)
89
31
30
29
ltP ~u
J
1 T
-~Lti=t~-t--t i~+--Ij Tmu1lff =31473 middot005222x 28
1 1 1middot 1 l i l i bullbullbullbullbullbullbull__ bullbullbullbull_ bullbullbullbullbullbullbull~_bullbullbullbullbullbullbullbullbulla bullbullbullbullbullbullbullbullbullbullbull a 27
~ Tm~llfz = 26857 + 01734x _~__+_+II i
26
bullmiddotmiddotbullbullbullmiddotmiddotbullibullbullbullbullbullbullbullbullbullbullbullmiddotmiddotmiddotbullbullbullbullbullbullbullbullmiddotmiddotmiddotmiddot bullbullbullbullbullbullbullbullbull-i-~-i-ii25
JJ$~L-f$9 5 24
~ 23 middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotlmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot+middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot~middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot+middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1-middotmiddot T mllff =25622 bull 002~7X c-bullbullbullbullbullbullbullbullbullbullbullbull+ ~~ 22 rp 1 1 i i 1 1 1
21 = 19464 + 02548 jmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddott Upper Limitmullfz xii 0
4-bullbullbullbullbullbullbullbullbullbullbullbullimiddotmiddotmiddotbullbullbullbullbullbullmiddotf20 i 1 ~ 1
19
0 1 2 3 4 5 6 7 8 9 10
TIC I
Fig E14 Mullion Temperature Profile Run I (RightHeater On)
33 i
middotmiddotmiddotmiddotlaquomiddotmiddotmiddotmiddot------------------------------- c--------middotmiddotmiddot-middot-----------middotmiddotmiddot---middotmiddot--------l-----middot-----I-----32
= 2757 + 017006x ILLJ1
a
31
30
29~
i 28
Run2
TmulIfz
T~ulIfz ~
-~t=ii~Ii~~~~ i
27 middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot9-middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotT~~middotmiddotmiddotmiddotmiddot2s944-middot~middotmiddotO0278~middotmiddote 26~ r~rrTt+rr25
24 2320~ + O~S4x middotmiddotlmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotjmiddot ~ u~ L~t 23 middotmiddotmiddotmiddotmiddotmiddotmiddotmiddot~middotmiddotmiddotmiddotmiddotmiddotmiddot+middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot+middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot+middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotImiddotmiddotj 0 Lower Limit
22
0 1 2 3 4 5 6 7 8 9 10
TIC I
Fig EIS Mullion Temperature Profile Run 2 (RightlHeater On)
90
33 i i ~ _______ _ _~____ __ __-i--bullbullbullbullbullbullbullbull-t------ -- uu__~ ~ --~32
=1268931+ 0~4~14X 111131
30
a 29~
I 28
Run3
Tmullfz
i t+ I T
m
mnplusmn~~27 6 i 1 i 1 +++ T mullff =28912 - 002938x 26~ +middotmiddot++Imiddotjmiddott-25
= 22996 + 02312x 1middotmiddot+ 24
~~~~L lL1 0 ~23 ill 0 22
0 1 2 3 4 5 6 7 8 9 10
TIC
Fig E16 Mullion Temperature Profile Run 3 (RightHeater On)
91
APPENDIX F NUMERICAL SIMULATION EQUATIONS AND CODE
F1 Finite-Difference Equations
Figure Fl is a generic resistor network that is used as a base for all the finite-difference
equations The general fonn is
(Fl)
r----II ij+l
J
i j-l L ______--J
Fig F1 Generic Nodal Resistor Network
This makes it easy to simply plug in the different resistors for the different regions of the
section There are twelve resistors total The following table summarizes the resistors
needed to complete the model
Table F1 Model Resistors
Description Resistance [CIW]
Interior insulation x direction Rl= dx dymiddotkinsmiddotb
92
dyInterior insulation y direction R2= dx-kins-b
dySteel parallel with insulation y direction R3= km-dm-b + kins-(dx -dm)
dxR=Steel parallel with insulation x direction km-dm-b + kins-(dy -dm)
dyRs=Plastic parallel with insulation y direction
kp-dp-b + kins-(dx -dp)
dxPlastic parallel with insulation x direction R6= kp-dp-b + kins-(dy -dp)
heffa- (~- dm) + kinsSteel to exterior x direction R7= 2
heffo-kins-dy-b
heffa- (dY - dm) + kinsSteel to exterior y direction R - 28shyheffo-kins-dx-b
hefti- (dY _dm) + kinsSteel to interior y direction R9= 2
heffi-kins-dx-b
hefti- (~- dp) + kinsPlastic to interior x direction RIO= 2
heffi-kins-dy-b
Rll = hefti- (dJ -dP) + kinsPlastic to interior y direction
heffi-kins-dx-b
93
Steel skinplastic skin interface
2middotkmmiddotdmmiddotkpmiddotdpmiddotdxR12=----------------------~~----------------
2middotkmmiddotdmmiddotkpmiddotdpmiddotbmiddot(dy -dp) + (kpmiddotdp + kmmiddotdm)middotbmiddotdx2
F2 Wall Simulation Source Code
Program FiniteDiff
c This program simulates the conductive heat transfer through the wall section c of the refrigerator near the door gasket using Guass-Siedel iteration c The program allows for flexibility in the geometry and material properties c The program is a steady-state model
cVariable Definitions
c km = conductivity of the outer metal skin (Wm-K) c kins = conductivity of the polyurethane foam insulation (Wm-K) c kp conductivity of the inner plastic skin (Wm-K) c dm = thickness of the metal skin (mm) c dp = thickness of the plastic skin (mm) c b = depth of the section (m) c heffo = effective heat transfer coefficient on outside surfaces (Wm2-K) c heffi = effective heat transfer coefficient on inside surfaces (Wm2-K) c sl width of wall inSUlation (mm) c s2 length of wall section (mm) c s3 seal indentation (mm) c s4 seal width (mm) c s5 distance metal skin travels into cabinet (mm) c s6 distance platic skin travels out of cabinet (mm) c ns = number of nodes corresponding to the s regions above c rs = network resistors (m-eW) c i = integer values of distance along the x axis c j = integer values of distance along the y axis c imax maximum integer value in x direction c jmax maximum integer value in y direction c iter total number of iterations to converge c loop convergence flag c Qinl Heat flux per unit length across the outer boundary (Wm) c Qin2 Heat flux per unit length across the inner boundary (Wm) c Qdif Qinl - Qin2 (Wm) c Qpdif = percent difference between the heat fluxes Qinl and Qin2 c Ti Inside ambient temperature (e) c To = Outside ambient temperature (e)
cDeclare Variables
INTEGER nln2n3n4n5n6ijloopimaxjmaxiter INTEGER clflaglflag2 REAL kmkinskpdmdpdxdyheffoheffi REAL TiToQdifQpdifQinlQin2 REAL sls2s3s4s5s6lenoutlenin REAL rlr2r3r4r5r6r7r8r9rlOrllr12 REAL T(-1lOl-1lOl)bqlDsumlsum2 REAL Qm(lOl)qfluxm(lOl)fluxo(OlOl)fluxi(OlOl)
94
REAL fluxcen(0101)pfluxcen(0101)pfluxo(0101) REAL pfluxi(0101)pmaxdifoneDtolaq2Dqedge1
OPEN (10file-2Dcode(v11)out1position-rewind) OPEN (11file-2Dcode(v11)out2position=rewind)
cTest Parameters
c thermal conductivity of the outer metal skin (Wm K) km-540
c thermal conductivity of the wall insulation (Wm K) kins=0021
c thermal conductivity of the inner plastic skin (Wm K) kp=015
c thickness of the metal skin (mm) dm=065
c thickness of the plastic skin (mm) dp=25
c effective heat transfer coefficient on outside surfaces (Wm2-K) heffo=681
c effective heat transfer coefficient on inside surfaces (Wm2-K) heffi=610
c width of section (mm) sl=450
c length of section (mm) s2=2000
c depth of the section (m) b=10
c inside ambient temperature (C) Ti=95
c outside ambient temperature (C) To=210
c unit conversions dm=dm1000 dp=dp1000 sl=sl1000 s2=s21000
c specify 1-dimensional tolerance (t) oneDtol=30
cMesh Parameters
c specify the following nodal mesh parameters n1=20 n2=80 n3=1 n4=9 n5=10
c various mesh dimensions dx=sln1 dy=s2n2 s3=n3dx s4=n4dx s5=n5dx s6=sl-s5-dx n6=s6dx imax=n1-1 jmax=n2-1
cInitialize temperature matrix
DO 10 j=-1jmax+1 DO 20 i=-1imax+1 T(ij)=Ti
95
20 CONTINUE 10 CONTINUE
DO 30 j=Ojmax T(-Ij)=To
30 CONTINUE
DO 40 i=0n3 T(i-I)=To
40 CONTINUE
DO 50 j=Ojmax T(imax+lj)=Ti
50 CONTINUE
DO 60 i=n3+n4+1imax T(i-I)=Ti
60 CONTINUE
cResistors [m-CW]
c interior insulation x direction rl=dx(kinsdy)
c interior insulation y direction r2=dy(kinsdx)
c metalinsulation y direction r3=dy(kmdm+kins(dx-dm))
c metalinsulation x direction r4=dx(kmdm+kins(dy-dm))
c plasticinsulation y direction r5=dy(kpdp+kins(dx-dp))
c plasticinsulation x direction r6s dx(kpdp+kins(dy-dp))
c metal to exterior x direction r7=(heffolaquodx2)-dm)+kins)(heffokinsdy)
c metal to exterior y direction rB=(heffo laquody2)-dm) +kins)(heffokinsdx)
c metal to interior y direction r9=(heffilaquody2)-dm)+kins)(heffikinsdx)
c plastic to interior x direction rl0=(heffilaquodx2)-dp)+kins)(heffikinsdy)
c plastic to interior y direction rll=(heffilaquody2)-dp)+kins)(heffikinsdx)
c metalplastic interface rI2=(2kmdmkpdpdx)(2kmdmkpdp(dy-dp) + (kpdp+km dm)dxdx)
cxxxxxGuass-Siedel Iterationxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx loop=1 iter=1 DO WHILE (loop eq 1)
c Equations for row 0 i=O j=O CALL sseqn(Tr4r7r3rBijimaxjmax)
DO 70 i=ln3 j=O CALL sseqn(Tr4r4r2rBijimaxjmax)
70 CONTINUE
DO 75 i=n3+1n5-1
96
j=O IF (i le n3+n4) THEN
CALL sseqn(Tr4r4r21e20ijimaxjmax) ELSE
CALL sseqn(Tr4r4r2r9ijimaxjmax) ENDIF
75 CONTINUE
i=n5 j-O IF (i le n3+n4) THEN
CALL sseqn(Tr12r4r21e20ijimaxjmax) ELSE
CALL sseqn(Tr12r4r2r9ijimaxjmax) ENDIF
i=n5+1 j=O IF (i le n3+n4) THEN
CALL sseqn(Tr6r12r21e20ijimaxjmax) ELSE
CALL sseqn(Tr6r12r2rllijimaxjmax) ENDIF
DO 80 i=n5+2imax-l j=O IF (i le n3+n4) then
CALL sseqn(Tr6r6r21Oe20ijimaxjmax) ELSE
CALL sseqn(Tr6r6r2rllijimaxjmax) ENDIF
80 CONTINUE
i=imax j=O CALL sseqn(TrlOr6r5rllijimaxjmax)
c Equations for rows 1 thru jmax-l DO 90 j=ljmax-l
i=O CALL sseqn(Tr1r7r3r3ijimaxjmax)
DO 100 i=1imax-1 CALL sseqn(Tr1r1r2r2ijimaxjmax)
100 CONTINUE
i=imax CALL sseqn(Tr10r1r5r5ijimaxjmax)
90 CONTINUE
c Equations for row jmax j=jmax i=O CALL sseqn(Tr1r710e20r3ijimaxjmax)
DO 110 i=1imax-1 j=jmax CALL sseqn(Tr1r110e20r2ijimaxjmax)
110 CONTINUE
i=imax j=jmax CALL sseqn(Tr10r11Oe20r2ijimaxjmax)
97
c c c
Compute the difference in heat flux crossing the outer boundary and crossing the inner boundaryr ideally the difference should be zero
CALL balance(TToTidxdyn3n4imaxjmaxQdifQpdif c QinlQin2r7r9r8rlOrllb)
c Update loop variables iter-iter+l
c Convergence criterium IF (Qpdif le 20) then
loop-O ENDIF IF (iter eq 10000) THEN loop=O write(lO) Solution did not converge
ENDIF
END DO cxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
cHeat Transfer Calculations
c Compute 10 heat flux through wall CALL oneD (ToTiheffoheffikmkinskpdmdpslqlD)
c Compute the flux thru wall at each node on the c outside and inside walls [Wm2) Also the flux c in the x-direction across the center line of the c section
cl-int(nl2) fluxcen(0)=(1(r4dy))(T(cl0)-T(cl+l0)) fluxo(0)=(1(r7dy))(To-T(00)) fluxi(O)=(l(rlOdy))(T(imaxO)-Ti) DO 112 j=ljmax
fluxcen(j)=(l(rldy))(T(clj)-T(cl+lj)) fluxo(j)=(1(r7dy))(To-T(0j)) flumiddotxi (j) =(1 (rlOdy)) (T (imax j)-Ti)
112 CONTINUE
c Determine the percent of steady-state 10 losses DO 113 j=Ojmax
pfluxcen(j)=(fluxcen(j)qlD) 100 pfluxo(j)=(fluxo(j)qlD)lOO pfluxi(j)=(fluxi(j)qlD)lOO
113 CONTINUE
c Determine where the heat transfer becomes 10 c based on a criticle percentage
flagl=O DO 114 j=O jmax
a=abs(pfluxcen(j)-lOOO) IF (j ne jmax) THEN
IF (a le oneDtol) THEN jstar=j
ENDIF ELSE
IF (a le oneDtol) THEN jstar=j
ELSE flagl=l
ENDIF ENDIF
98
114 CONTINUE
c Determine the edge loss by subtracting the 10 heat c transfer from the heat transfer in the 20 region c across the centerline
flag2=0 IF (flagl eq 0) THEN
q2D=00 DO 115 j=O jstar
q2D-q2D+fluxcen(j) 115 CONTINUE
qedgel=q2D-qlD ELSE
flag2=1 ENDIF
c 10 heat flux along metal skin under the seal into c the cabinet [Wm2J Fluxes for all metal nodes are c computed as well as an average flux The flux from c node (n3+l0) to node (n3+20) is given as qlDm(l) c and so on Assume the temperature of the metal skin c is the temperature of the node at that location
suml=OO sum2=00 DO 119 i=n3+1n3+n4-l
Qm(i)=laquokmdmb)dx)(T(i0)-T(i+10raquo qfluxm(i)=(kmdx)(T(iO)-T(i+lOraquo suml=suml+Qm(i) sum2=sum2+qfluxm(i)
119 CONTINUE pmaxdif=laquoQm(n3+n4-l)-Qm(n3+1raquoQm(n3+lraquo100 qedge2-qfluxm(cl)
cOutput
c Output nodal temperatures to separate file DO 120 j=Ojmax
write(ll) (T(ij)i=Oimax) 120 CONTINUE
c Output flux info to a different file write(10) INPUT PARAMETERS write(lO) write (10 ) Section Dimensions (mm) write(lO) Width sl1000 write (10 ) Length s21000 write(10) Depth blOOO write(10) Steel skin thickness dmlOOO write(lO) Plastic skin thickness dplOOO write(lO) write(10) Mesh Geometry write(10) dx dxlOOO write(lO) dy dylOOO write(lO) Number nodes in x-direction n1 write(lO) Number nodes in y-direction n2 write(lO) Number of steel skin nodes write(lO) (including corner 00) n5+l write(10) Steel nodes under the seal n3+1 ton3+n4 write(10) write(lO) Steel skin conductivity (Wm K) km write(lO) Foam insulation conductivity (Wm K) kins write(lO) Plastic skin conductivity (Wm K) kp write(lO) Outside h (Wm2 K) heffo write(lO) Inside h (Wm2 K) heffi
99
write(10) Outside Temp (C) To write(10) Inside Temp (C) Ti write(10) write (10 ) write(10) write(10) OUPUT PARAMETERS write (10 ) write(10) Number of iterations iter write(10) write(10) Heat Transfer for the Section write(10) OVerall Heat Transfer (W) Qin1 write(10) 10 Heat Flux Thru Wall (Wm2) q1D write (10 ) write(10) Heat Transfer Along Metal Skin Under Seal write(10) node to node qm[Wm2J Qm[WJ DO 135 i=n3+1n3+n4-1
write(10) i i+1 qfluxm(i) Qm(i) 135 CONTINUE
write (10 ) Maximum difference () abs (pmaxdif) write(10) IF (flag2 eq 1) THEN
write(10) The mesh does not extend far enough write(10) in the y-direction to reach 10 heat write(10) transfer for the specified tolerance write(10) ofoneDtol
ELSE write (10 ) Edge loss computed from qe=q2D-q1D qedge1 write (10 ) write(10) Edge loss computed directly from write(10) steel skin ~T at centerline qedge2
ENDIF write (10 ) write (10 ) write(10) Heat fluxes in thru the section write(10) along the centerline [Wm2J write (10 ) write(10) j flux 10 DO 136 j=Ojmax
write(10) j fluxcen(j) pfluxcen(j) 136 CONTINUE
PAUSE STOP END
C
SUBROUTINE sseqn (Trplusirminusirplusjrminusj i jimax jmax)
c This subroutine computes the temperature at node (ij) c given the temperatures of the surrounding nodes and c the resistances leading to these nodes
INTEGER ijimaxjmax REAL T(-1101-1101)rplusirminusirplusjrminusj REAL c1c2c3c4c5
c1=1rplusi c2=1rminusi c3=1rplusj c4=1rminusj c5=c1+c2+c3+c4
T(ij)=(1c5)(c1T(i+1j)+c2T(i-1j)+c3T(ij+1)+c4T(ij-1raquo
100
RETURN END
C
SUBROUTINE balance(TToTidxdyn3n4imaxjmaxQdifQpdif c Qin1Qin2r7r8r9r10r11b)
c This subroutine computes the steady-state heat balance c for the cross-section
INTEGER imaxjmaxijn3n4 REAL T(-1101-1101)TlToQin1Qin2dydx REAL r7r8r9r10r11b
c Compute the heat entering Qin1 [Wj Qin1=00 DO 10 jOjmax
Qin1=Qin1+(b(r7))(To-T(0j)) 10 CONTINUE
DO 20 i=0n3 Qin1=Qin1+(b(r8))(To-T(i0))
20 CONTINUE
c Compute the heat leaving Qin2 [Wj Qin2=00 DO 30 j=Ojmax
Qin2=Qin2+(b(r10))(T(imaxj)-Ti) 30 CONTINUE
DO 40 i=n3+n4+1imax IF (i le nS) then
Qin2=Qin2+(b(r9))(T(i0)-Ti) ELSE
Qin2=Qin2+(b(r11))(T(i0)-Ti) ENDIF
40 CONTINUE
c Compute the absolute difference in heat fluxes [Wj Qdif=abs(Qin2-Qin1)
c Compute the percent difference in the heat transfers [Wj Qpdif=(QdifQin1) 100
RETURN END
C
SUBROUTINE oneD (ToTiheffoheffikmkinskpdmdpslqlD)
c This subroutine compute the one-dimensional c heat flux through the section wall
INTEGER i REAL ToTiheffoheffikmkinskpdmdpsl REAL q1DReqdins
dins=sl-dm~dp
Req=(lheffo) + (dmkm) + (dinskins) +(dpkp)+(lheffi) q1D=(To-Ti)Req
RETURN END
101
F3 Fresh Food Wan Simulation Output
INPUT PARAMETERS
Section Dimensions (mm) Width 4500 Length 2000 Depth 1000 Steel skin thickness 6500 Plastic skin thickness 2500
Mesh Geometry dx 2250 dy 2500 Number nodes in x-direction 20 Number nodes in y-direction 80 Number of steel skin nodes (including corner 00) 11 Steel nodes under the seal 2 to 10
Steel skin conductivity (Wm K) 5400 Foam insulation conductivity (Wm K) 21000E-02 Plastic skin conductivity (Wm K) 1500 Outside h (Wm2 K) 6810 Inside h (Wm2 K) 6100 Outside Temp (C) 2100 Inside Temp (C) 4000
OUPUT PARAMETERS
Number of iterations 5318
10 Heat Flux Thru Wall (Wm2) 9132
Heat Transfer Along Metal Skin Under Seal node to node qm[Wm2] Qm[W]
2 3 1619 1092 3 4 1612 1081 4 5 1660 1019 5 6 1645 1010 6 1 1626 1051 1 8 1601 1041 8 9 1569 1020 9 10 1521 9922
Maximum difference () 9101
Edge loss computed directly from steel skin 1T at centerline 1645
Heat fluxes in thru the section along the centerline [Wm2]
j flux 10 0 4284 4691 1 2246 2459 2 3513 3841 3 4554 4981 4 5311 5881 5 6001 6512 6 6488 1104 1 6868 1520
102
10
20
30
40
50
60
70
8 7169 7850 9 7412 8117
7612 8335 11 7778 8517 12 7918 8670 13 8037 8800 14 8139 8912 15 8227 9008 16 8303 9092 17 8369 9164 18 8428 9228 19 8479 9285
8525 9334 21 8565 9379 22 8601 9418 23 8634 9454 24 8663 9486 25 8690 9515 26 8714 9542 27 8736 9566 28 8756 9588 29 8775 9609
8793 9628 31 8809 9645 32 8824 9662 33 8838 9677 34 8851 9692 35 8863 9705 36 8875 9718 37 8886 9730 38 8896 9742 39 8906 9752
8916 9763 41 8925 9772 42 8933 9782 43 8941 9791 44 8949 9799 45 8956 9807 46 8963 9815 47 8970 9822 48 8976 9829 49 8982 9836
8988 9842 51 8994 9848 52 8999 9854 53 9004 9859 54 9009 9864 55 9013 9869 56 9017 9874 57 9021 9878 58 9025 9883 59 9029 9887
9032 9890 61 9036 9894 62 9039 9897 63 9042 9901 64 9044 9903 65 9047 9906 66 9049 9909 67 9051 9911 68 9053 9913 69 9055 9915
9057 9917 71 9058 9919
103
72 9059 9920 73 9061 9921 74 9062 9922 75 9062 9923 76 9063 9924 77 9063 9924 78 9064 9925 79 9064 9925
j local Qwall [Wl
-1 3215 0 -45410E-02 1 -50708E-02 2 -40940E-02 3 -33836E-02 4 -27620E-02 5 -23180E-02 6 -1 9628E-02 7 -1 6076E-02 8 -1 4300E-02 9 -12524E-02 10 -10748E-02 11 -98601E-03 12 -89722E-03 13 -80842E-03 14 -71962E-03 15 -63081E-03 16 -63082E-03 17 -54202E-03 18 -54202E-03 19 -45322E-03 20 -45322E-03 21 -45322E-03 22 -45321E-03 23 -36442E-03 24 -36442E-03 25 -36442E-03 26 -27562E-03 27 -27561E-03 28 -27561E-03 29 -27561E-03 30 -27561E-03 31 -18682E-03 32 -18682E-03 33 -27561E-03 34 -18682E-03 35 -18682E-03 36 -18681E-03 37 -18682E-03 38 -98018E-04 39 -98018E-04 40 -98018E-04 41 -98018E-04 42 -98018E-04 43 -98018E-04 44 -98018E-04 45 -98018E-04 46 -98018E-04 47 -18682E-03 48 -98018E-04 49 -98018E-04 50 -98018E-04 51 -98018E-04 52 -98018E-04
104
53 -98018E-04 54 -92160E-05 55 -98018E-04 56 -98018E-04 57 -98018E-04 58 -98018E-04 59 -98018E-04 60 -92160E-05 61 -98018E-04 62 -92160E-05 63 -98018E-04 64 -98018E-04 65 -92160E-05 66 -98018E-04 67 -98018E-04 68 -92245E-05 69 -92245E-05 70 -98018E-04 71 -98018E-04 72 -98018E-04 73 -92160E-05 74 -92160E-05 75 -92160E-05 76 -92160E-05 77 -92160E-05 78 -92160E-05 79 -92160E-05
Qwallff [Wm21 = 1442 Qwallff [WI = 2775
Fresh Food Nodal Temperatures
x(mm) v(mm) 1125 3375 5625 7875 10125 12375 14625 16875 19125 21375
125 1761 1755 1748 1741 1734 1727 172 1713 1706 17 375 1768 1753 1738 1723 1707 169 1671 165 1624 1589 625 1775 1752 173 1706 1682 1656 1626 1593 1552 15 875 1781 1751 1722 1691 1659 1625 1587 1544 1494 1434
1125 -1787 1751 1715 1678 1639 1598 1553 1504 1448 1384 1375 1792 1751 1709 1667 1622 1576 1526 1471 1412 1346 1625 1798 1752 1705 1658 1609 1557 1503 1446 1384 ll17 1875 1803 1753 1702 165 1597 1543 1485 1425 1362 1294 2125 1808 1754 17 1645 1589 1531 1471 1409 1344 1276 2375 1813 1756 1699 1641 1582 1522 146 1396 133 1262 2625 1817 1758 1698 1638 1577 1515 1451 1386 132 1251 2875 1822 176 1698 1636 1573 151 1445 1379 1311 1242 3125 1826 1762 1699 1635 1571 1506 144 1373 1304 1235 3375 183 1765 17 1635 1569 1503 1436 1368 1299 1229 3625 1834 1768 1701 1635 1568 1501 1433 1364 1295 1225 3875 1837 177 1703 1635 1568 15 1431 1362 1292 1222 4125 1841 1773 1705 1636 1568 1499 143 136 129 1219 4375 1845 1776 1707 1638 1568 1499 1429 1359 1289 1218 4625 1848 1778 1709 1639 1569 1499 1429 1358 1288 1216 4875 1851 1781 1711 164 157 15 1429 1358 1287 1216 5125 1854 1784 1713 1642 1571 15 1429 1358 1287 1215 5375 1857 1786 1715 1644 1573 1501 143 1358 1287 1215 5625 186 1789 1717 1646 1574 1502 1431 1359 1287 1215
105
5875 1863 1791 1719 1647 1576 1504 1432 136 1288 1215 6125 1866 1794 1721 1649 1577 1505 1433 136 1288 1216 6375 1868 1796 1723 1651 1579 1506 1434 1361 1289 1216 6625 1871 1798 1725 1653 158 1508 1435 1362 129 1217 6875 1873 18 1727 1655 1582 1509 1436 1363 1291 1218 7125 1876 1803 1729 1656 1583 151 1437 1364 1291 1218 7375 1878 1805 1731 1658 1585 1512 1439 1366 1292 1219 7625 188 1807 1733 166 1587 1513 144 1367 1293 122 7875 1882 1809 1735 1661 1588 1515 1441 1368 1294 1221 8125 1884 181 1737 1663 159 1516 1442 1369 1295 1222 8375 1886 1812 1738 1665 1591 1517 1444 137 1296 1223 8625 1888 1814 174 1666 1592 1519 1445 1371 1297 1224 8875 189 1816 1742 1668 1594 152 1446 1372 1298 1225 9125 1892 1817 1743 1669 1595 1521 1447 1373 1299 1225 9375 1893 1819 1745 1671 1596 1522 1448 1374 13 1226 9625 1895 182 1746 1672 1598 1524 1449 1375 1301 1227 9875 1896 1822 1748 1673 1599 1525 145 1376 1302 1228 10125 1898 1823 1749 1674 16 1526 1451 1377 1303 1229 10375 1899 1825 175 1676 1601 1527 1452 1378 1304 123 10625 1901 1826 1751 1677 1602 1528 1453 1379 1305 123 10875 1902 1827 1753 1678 1603 1529 1454 138 1305 1231 11125 1903 1828 1754 1679 1604 153 1455 1381 1306 1232 11375 1904 183 1755 168 1605 1531 1456 1381 1307 1232 11625 1906 1831 1756 1681 1606 1532 1457 1382 1308 1233 11875 1907 1832 1757 1682 1607 1532 1458 1383 1308 1234 12125 1908 1833 1758 1683 1608 1533 1458 1384 1309 1234 12375 1909 1834 1759 1684 1609 1534 1459 1384 131 1235 12625 191 1835 176 1685 161 1535 146 1385 131 1235 12875 1911 1836 1761 1686 1611 1536 1461 1386 1311 1236 13125 1912 1837 1761 1686 1611 1536 1461 1386 1311 1236 13375 1913 1837 1762 1687 1612 1537 1462 1387 1312 1237 13625 1913 1838 1763 1688 1613 1538 1462 1387 1312 1237 13875 1914 1839 1764 1688 1613 1538 1463 1388 1313 1238 14125 1915 184 1764 1689 1614 1539 1464 1388 1313 1238 14375 1916 184 1765 169 1614 1539 1464 1389 1314 1239 14625 1916 1841 1766 169 1615 154 1465 1389 1314 1239 14875 1917 1842 1766 1691 1616 154 1465 139 1315 1239 15125 1918 1842 1767 1691 1616 1541 1465 139 1315 124 15375 1918 1843 1767 1692 1616 1541 1466 1391 1315 124 15625 1919 1843 1768 1692 1617 1542 1466 1391 1316 124 15875 1919 1844 1768 1693 1617 1542 1467 1391 1316 1241 16125 192 1844 1769 1693 1618 1542 1467 1392 1316 1241 16375 192 1844 1769 1694 1618 1543 1467 1392 1317 1241 16625 192 1845 1769 1694 1618 1543 1468 1392 1317 1241 16875 1921 1845 177 1694 1619 1543 1468 1392 1317 1242 17125 1921 1846 177 1694 1619 1544 1468 1393 1317 1242 17375 1921 1846 177 1695 1619 1544 1468 1393 1317 1242 17625 1922 1846 1771 1695 1619 1544 1469 1393 1318 1242 17875 1922 1846 1771 1695 162 1544 1469 1393 1318 1242 18125 1922 1847 1771 1695 162 1544 1469 1393 1318 1243 18375 1922 1847 1771 1696 162 1545 1469 1394 1318 1243 18625 1923 1847 1771 1696 162 1545 1469 1394 1318 1243 18875 1923 1847 1771 1696 162 1545 1469 1394 1318 1243 19125 1923 1847 1772 1696 162 1545 1469 1394 1318 1243 19375 1923 1847 1772 1696 162 1545 1469 1394 1318 1243 19625 1923 1847 1772 1696 1621 1545 1469 1394 1318 1243 19875 1923 1847 1772 1696 1621 1545 1469 1394 1318 1243
106
x(mm) y(mm) 23625 25875 28125 30375 32625 34875 37125 39375 41625 43875
125 1694 1662 1287 1033 8577 7336 6444 5795 5324 4995 375 1536 144 125 1068 9163 7946 6974 6189 5532 4944 625 1431 1334 1203 1066 9379 8252 7275 6423 5657 4935 875 136 127 1164 1051 9408 8374 7423 6548 573 4941
1125 131 1226 1132 1034 9353 8394 7477 6605 5766 4948 1375 1273 1193 1107 1017 9262 836 7478 6618 5779 4952 1625 1245 1168 1086 1002 9162 8302 7449 6607 5776 4951 1875 1223 1148 1069 9886 9064 8236 7408 6583 5764 4948 2125 1205 1132 1055 977 8974 8169 7362 6554 5747 4941 2375 1191 1119 1044 9671 8893 8107 7316 6522 5728 4933 2625 118 1108 1034 9588 8824 8051 7273 6492 5709 4925 2875 1172 11 1026 9518 8764 8002 7235 6464 5691 4916 3125 1164 1093 102 946 8713 796 7201 6439 5674 4908 3375 1159 1087 1015 9412 8671 7924 7172 6417 566 49 3625 1154 1083 101 9373 8636 7894 7148 6399 5647 4894 3875 1151 1079 1007 9341 8608 7869 7128 6383 5636 4888 4125 1148 1077 1004 9316 8585 7849 7111 637 5627 4883 4375 1146 1074 1002 9296 8566 7833 7097 6359 5619 4879 4625 1145 1073 1001 9281 8552 7821 7087 6351 5613 4875 4875 1144 1072 9995 927 8541 7811 7078 6344 5609 4872 5125 1143 1071 9987 9261 8533 7803 7072 6339 5605 487 5375 1143 1071 9982 9256 8528 7798 7067 6335 5602 4868 5625 1143 107 9979 9253 8524 7795 7064 6332 56 4867 5875 1143 107 9978 9251 8522 7793 7062 6331 5599 4866 6125 1143 1071 9979 9251 8522 7792 7061 633 5598 4866 6375 1144 1071 9981 9252 8523 7792 7061 633 5598 4865 6625 1144 1071 9984 9255 8524 7793 7062 633 5598 4865 6875 1145 1072 9988 9258 8526 7795 7063 6331 5598 4865 7125 1145 1072 9993 9261 8529 7797 7065 6332 5599 4866 7375 1146 1073 9998 9265 8533 78 7067 6333 56 4866 7625 1147 1074 10 927 8536 7803 7069 6335 5601 4867 7875 1148 1074 1001 9275 854 7806 7072 6337 5602 4867 8125 1148 1075 1001 928 8545 7809 7074 6339 5603 4868 8375 1149 1076 1002 9285 8549 7813 7077 6341 5605 4869 8625 115 1076 1003 929 8553 7817 708 6343 5606 4869 8875 1151 1077 1003 9295 8558 782 7083 6345 5608 487 9125 1152 1078 1004 93 8562 7824 7086 6347 5609 4871 9375 1152 1078 1004 9306 8567 7828 7089 635 5611 4872 9625 1153 1079 1005 9311 8571 7831 7092 6352 5612 4873 9875 1154 108 1006 9316 8575 7835 7094 6354 5614 4873 10125 1155 108 1006 9321 858 7838 7097 6356 5615 4874 10375 1155 1081 1007 9326 8584 7842 71 6358 5617 4875 10625 1156 1082 1007 933 8588 7845 7103 636 5618 4876 10875 1157 1082 1008 9335 8592 7848 7105 6362 5619 4876 11125 1157 1083 1008 9339 8596 7852 7108 6364 5621 4877 11375 1158 1083 1009 9344 8599 7855 711 6366 5622 4878 11625 1158 1084 1009 9348 8603 7858 7113 6368 5623 4879 11875 1159 1084 101 9352 8606 7861 7115 637 5625 4middot879 12125 116 1085 101 9356 861 7864 7117 6372 5626 488 12375 116 1085 1011 936 8613 7866 712 6373 5627 488 12625 1161 1086 1011 9363 8616 7869 7122 6375 5628 4881 12875 1161 1086 1011 9367 8619 7871 7124 6376 5629 4882 13125 1162 1087 1012 937 8622 7874 7126 6378 563 4882 13375 1162 1087 1012 9373 8625 7876 7128 6379 5631 4883 13625 1162 1087 1013 9376 8627 7878 7129 6381 5632 4883
107
13875 1163 1088 1013 9379 863 788 7131 6382 5633 4884 14125 1163 1088 1013 9382 8632 7882 7133 6383 5634 4884 14375 1164 1089 1013 9384 8634 7884 7134 6384 5634 4885 14625 1164 1089 1014 9387 8636 7886 7136 6385 5635 4885 14875 1164 1089 1014 9389 8638 7888 7137 6386 5636 4885 15125 1165 1089 1014 9392 864 7889 7138 6387 5637 4886 15375 1165 109 1015 9394 8642 7891 714 6388 5637 4886 15625 1165 109 1015 9396 8644 7892 7141 6389 5638 4886 15875 1165 109 1015 9398 8646 7894 7142 639 5638 4887 16125 1166 109 1015 9399 8647 7895 7143 6391 5639 4887 16375 1166 1091 1015 9401 8649 7896 7144 6392 5639 4887 16625 1166 1091 1016 9403 865 7897 7145 6392 564 4888 16875 1166 1091 1016 9404 8651 7898 7146 6393 564 4888 17125 1167 1091 1016 9405 8652 7899 7146 6394 5641 4888 17375 1167 1091 1016 9406 8653 79 7147 6394 5641 4888 17625 1167 1091 1016 9407 8654 7901 7148 6395 5641 4888 17875 1167 1092 1016 9408 8655 7902 7148 6395 5642 4889 18125 1167 1092 1016 9409 8656 7902 7149 6395 5642 4889 18375 1167 1092 1016 941 8656 7903 7149 6396 5642 4889 18625 1167 1092 1016 9411 8657 7903 715 6396 5642 4889 18875 1167 1092 1017 9411 8657 7904 715 6396 5643 4889 19125 1167 1092 1017 9412 8658 7904 715 6396 5643 4889 19375 1167 1092 1017 9412 8658 7904 715 6397 5643 4889 19625 1167 1092 1017 9412 8658 7904 715 6397 5643 4889 19875 1168 1092 1017 9412 8658 7904 715 6397 5643 4889
F4 Freezer Wall Simulation Output
INPUT PARAMETERS
Section Dimensions (mm) Width 5600 Length 2000 Depth 1000 Steel skin thickness 6500 Plastic skin thickness 2500
Mesh Geometry dx 2800 dy 2500 Number nodes in x-direction 20 Number nodes in y-direction 80 Number of steel skin nodes (including corner 00) 9 Steel nodes under the seal 2 to 8
Steel skin conductivity (Wm K) 5400 Foam insulation conductivity (Wm K) 27000E-02 Plastic skin conductivity (Wm K) 1500 Outside h (Wm2 K) 6870 Inside h (Wm2 K) 6410 Outside Temp (C) 2100 Inside Temp (C) -1000
OUPUT PARAMETERS
108
Number of iterations 5409
Heat Transfer for the Section OVerall Heat Transfer (WI 4518 10 Heat Flux Thru Wall (Wm21 1362
Heat Transfer Along Metal Skin Under Seal node to node
2 3 3 4 4 5 5 6 6 7 7 8
Maximum difference
qm[Wm2) Om(W) 3026 1967 3008 1955 2981 1938 2944 1914 2892 1880 2820 1833
(1 6799
Edge loss computed from qe=q20-q1D 1760
Edge loss compusteel skin AT
ted directly from at centerline 2981
Heat fluxes in thru the section along the centerline [Wm2)
j flux UO 0 7762 5698 1 3711 2724 2 5678 41 68 3 7275 5341 4 8508 6246 5 9437 6927 6 1013 7438 7 1066 7823 8 1106 8117 9 1137 8347 10 1162 8529 11 1182 8678 12 1199 8801 13 1213 8904 14 1225 8992 15 1235 9068 16 1244 9135 17 1252 9193 18 1259 9245 19 1266 9291 20 1271 9333 21 1276 9370 22 1281 9405 23 1285 9436 24 1289 9464 25 1293 9491 26 1296 9515 27 1299 9538 28 1302 9559 29 1305 9578 30 1307 9596 31 1310 9614 32 1312 9630 33 1314 9645 34 1316 9659 35 1318 9673 36 1319 9685 37 1321 9697
109
38 1323 9709 39 1324 9720 40 1325 9730 41 1327 9740 42 1328 9749 43 1329 9758 44 1330 9767 45 1332 9775 46 1333 9783 47 1334 97bull 90 48 1335 9797 49 1336 9804 50 1336 9810 51 1337 9816 52 1338 9822 53 1339 9828 54 1340 9833 55 1340 9838 56 1341 9843 57 1341 9847 58 1342 9852 59 1343 9856 60 1343 9859 61 1344 9863 62 1344 9866 63 1344 9870 64 1345 9873 65 1345 9875 66 1346 9878 67 1346 9880 68 1346 9882 69 1347 9884 70 1347 9886 71 1347 9888
72 1347 9889 73 1347 9891 74 1347 9892 75 1348 9893 76 1348 9893 77 1348 9894 78 1348 9894 79 1348 9894
j local Qwall [WI
-1 3067 0 -36774E-02 1 -40214E-02 2 -32314E-02 3 -25994E-02 4 -20859E-02 5 -16909E-02 6 -14144E-02 7 -12169E-02 8 -10589E-02 9 -90092E-03 10 -78242E-03 11 -70342E-03 12 -66392E-03 13 -58492E-03 14 -54542E-03 15 -50592E-03 16 -46642E-03 17 -42692E-03 18 -42692E-03
110
19 -38742E-03 20 -34792E-03 21 -30842E-03 22 -30842E-03 23 -30842E-03 24 -26892E-03 25 -26892E-03 26 -22942E-03 27 -22942E-03 28 -22942E-03 29 -22942E-03 30 -18992E-03 31 -1 8992E-03 32 -18992E-03 33 -18992E-03 34 -1 8992E-03 35 -1 5042E-03 36 -1 8992E-03 37 -15042E-03 38 -1 5042E-03 39 -11092E-03 40 -11092E-03 41 -11092E-03 42 -11092E-03 43 -11092E-03 44 -11092E-03 45 -11092E-03 46 -11092E-03 47 -71417E-04 48 -11092E-03 49 -71421E-04 50 -11092E-03 51 -71417E-04 52 -11092E-03 53 -71417E-04 54 -71421E-04 55 -71421E-04 56 -71417E-04 57 -31916E-04 58 -31920E-04 59 -31916E-04 60 -31916E-04 61 -71417E-04 62 -11421E-04 63 -71421E-04 64 -31920E-04 65 -31920E-04 66 -71417E-04 67 -31916E-04 68 -71417E-04 69 -31920E-04 70 -71421E-04 71 -31920E-04 72 -31920E-04 73 -71417E-04 74 -31916E-04 75 -31916E-04 76 -31916E-04 77 -31916E-04 78 -71417E-04 79 -71417E-04
Qwallfz [Wm2J = 2895 Qwallfz [WJ = 2721
111
Freezer Wan Nodal Temperatures
x(mm) y1mm 14 42 70 98 126 154 182 210 238 266
125 1507 1492 1477 1461 1445 143 1415 14 1385 1338 375 1519 1489 1458 1426 1392 1353 1307 1247 1154 972 625 1531 1486 1441 1393 1341 1282 1212 1121 9925 7989 875 1542 1484 1425 1363 1296 1221 1132 1023 8837 7014
1125 1553 1483 1412 1338 1258 117 1069 9508 809 6396 1375 1563 1483 1401 1317 1227 1129 102 8969 7563 5974 1625 1572 1483 1393 13 1202 1097 9824 8568 7184 5673 1875 1582 1485 1387 1287 1182 1072 9537 8269 6906 5452 2125 1591 1488 1384 1277 1167 1053 9321 8046 67 5288 2375 1599 1491 1382 1271 1157 1039 916 7881 6547 5164 2625 1608 1495 1381 1266 1149 1028 9041 7758 6433 5071 2875 1616 1499 1382 1264 1144 1021 8955 7668 6349 5002 3125 1623 1504 1384 1263 114 1016 8895 7604 6288 495 3375 1631 1509 1386 1263 1139 1013 8854 7559 6245 4913 3625 1638 1514 1389 1264 1138 1011 8829 753 6216 4888 3875 1645 1519 1393 1266 1139 1011 8816 7513 6198 4872 4125 1652 1524 1396 1269 114 1011 8813 7505 6188 4863 4375 1658 1529 14 1271 1142 1012 8817 7505 6185 486 4625 1664 1534 1405 1275 1144 1014 8826 751 6188 4861 4875 167 1539 1409 1278 1147 1016 884 752 6195 4867 5125 1676 1544 1413 1281 115 1018 8858 7533 6206 4875 5375 1682 1549 1417 1285 1153 102 8877 755 6219 4886 5625 1687 1554 1421 1289 1156 1023 8899 7568 6235 4899 5875 1692 1559 1425 1292 1159 1026 8923 7588 6252 4914 6125 1698 1563 143 1296 1162 1028 8947 7609 627 493 6375 1702 1568 1434 1299 1165 1031 8972 763 6289 4946 6625 1707 1572 1438 1303 1169 1034 8997 7653 6308 4964 6875 1712 1576 1441 1306 1172 1037 9022 7675 6329 4982 7125 1716 158 1445 131 1175 104 9048 7698 6349 5 7375 172 1584 1449 1313 1178 1043 9073 7721 6369 5018 7625 1724 1588 1452 1317 1181 1045 9098 7744 639 5036 7875 1728 1592 1456 132 1184 1048 9123 7766 641 5054 8125 1732 1595 1459 1323 1187 1051 9147 7788 643 5072 8375 1736 1599 1462 1326 1189 1053 917 781 645 509 8625 1739 1602 1465 1329 1192 1056 9194 7831 6469 5108 8875 1743 1605 1468 1332 1195 1058 9216 7852 6488 5125 9125 1746 1609 1471 1334 1197 1061 9238 7872 6507 5142 9375 1749 1612 1474 1337 12 1063 926 7892 6525 5158 9625 1752 1615 1477 134 1202 1065 9281 7911 6542 5174 9875 1755 1617 148 1342 1205 1067 9301 793 656 519 10125 1758 162 1482 1344 1207 1069 9321 7948 6576 5205 10375 1761 1623 1485 1347 1209 1071 934 7966 6593 522 10625 1763 1625 1487 1349 1211 1073 9358 7983 6608 5234 10875 1766 1627 1489 1351 1213 1075 9376 7999 6623 5248 11125 1768 163 1491 1353 1215 1077 9393 8015 6638 5262 11375 1771 1632 1494 1355 1217 1079 941 8031 6652 5275 11625 1773 1634 1496 1357 1219 1081 9426 8045 6666 5287 11875 1775 1636 1498 1359 1221 1082 9441 806 6679 53 12125 1777 1638 1499 1361 1222 1084 9456 8073 6692 5311 12375 1779 164 1501 1362 1224 1085 947 8087 6704 5322 12625 1781 1642 1503 1364 1225 1087 9483 8099 6716 5333 12875 1783 1644 1505 1366 1227 1088 9496 8111 6727 5344
112
13125 1784 1645 1506 1367 1228 109 9509 8123 6738 5353 13375 1786 1647 1508 1369 123 1091 9521 8134 6748 5363 13625 1788 1648 1509 137 1231 1092 9532 8145 6758 5372 13875 1789 165 151 1371 1232 1093 9543 8155 6768 5381 14125 1791 1651 1512 1373 1233 1094 9554 8165 6777 5389 14375 1792 1652 1513 1374 1235 1095 9564 8174 6785 5397 14625 1793 1654 1514 1375 1236 1096 9573 8183 6793 5404 14875 1794 1655 1515 1376 1237 1097 9582 8191 6801 5412 15125 1796 1656 1516 1377 1238 1098 959 8199 6808 5418 15375 1797 1657 1517 1378 1238 1099 9598 8206 6815 5425 15625 1798 1658 1518 1379 1239 11 9606 8213 6822 5431 15875 1799 1659 1519 138 124 1101 9613 822 6828 5436 16125 18 166 152 138 1241 1101 9619 8226 6834 5442 16375 18 1661 1521 1381 1242 1102 9626 8232 6839 5446 16625 1801 1661 1521 1382 1242 1103 9631 8237 6844 5451 16875 1802 1662 1522 1382 1243 1103 9637 8242 6848 5455 17125 1803 1663 1523 1383 1243 1104 9642 8247 6853 5459 17375 1803 1663 1523 1384 1244 1104 9646 8251 6857 5463 17625 1804 1664 1524 1384 1244 1105 965 8255 686 5466 17875 1804 1664 1524 1384 1245 1105 9654 8258 6863 5469 18125 1805 1665 1525 1385 1245 1105 9657 8261 6866 5471 18375 1805 1665 1525 1385 1245 1106 966 8264 6869 5474 18625 1805 1665 1525 1385 1246 1106 9662 8266 6871 5476 18875 1806 1666 1526 1386 1246 1106 9664 8268 6872 5477 19125 1806 1666 1526 1386 1246 1106 9666 827 6874 5479 19375 1806 1666 1526 1386 1246 1106 9667 8271 6875 548 19625 1806 1666 1526 1386 1246 1107 9668 8271 6876 548 19875 1806 1666 1526 1386 1246 1107 9668 8272 6876 5481
x(mm) v(mm) 294 322 350 378 406 434 462 490 518 546
125 549 054 -27 -5 -624 -727 -8 -85 -89 -92 375 548 171 -12 -338 -5 -624 -719 -795 -858 -914 625 51 22 -032 -24 -408 -543 -654 -748 -83 -907 875 474 238 0182 -175 -34 -482 -603 -71 -807 -898
1125 445 243 048 -132 -293 -436 -564 -68 -787 -89 1375 423 243 0653 -103 -259 -402 -534 -656 -772 -883 1625 406 24 0752 -084 -236 -378 -511 -638 -759 -877 1875 393 237 0808 -071 -219 -36 -495 -624 -749 -871 2125 382 233 0837 -063 -208 -348 -483 -614 -741 -867 2375 374 23 085 -058 -2 -339 -474 -606 -735 -863 2625 368 227 0855 -055 -195 -332 -467 -6 -731 -86 2875 363 225 0855 -053 -191 -328 -462 -596 -728 -858 3125 36 223 0853 -052 -189 -324 -459 -593 -725 -856 3375 357 221 0851 -051 -187 -322 -457 -59 -723 -855 3625 355 22 0849 -05 -186 -32 -455 -588 -722 -854 3875 354 219 0849 -049 -185 -319 -453 -587 -72 -853 4125 353 219 0849 -049 -184 -318 -452 -586 -72 -853 4375 353 219 0852 -049 -183 -317 -451 -585 -719 -852 4625 353 219 0855 -048 -183 -317 -451 -584 -718 middot852 4875 353 22 0861 -047 -182 -316 -45 -584 -718 -852 5125 354 22 0867 -047 -181 -315 -449 -584 -717 -851 5375 355 221 0875 -046 -181 -315 -449 -583 -717 -851 5625 356 222 0884 -045 -18 -314 -448 -582 -717 -851 5875 358 223 0894 -044 -179 -313 -448 -582 -716 -851 6125 359 225 0904 -043 -178 -313 -447 -582 -716 -851 6375 36 226 0915 -043 -177 -312 -447 -581 -716 -85
113
6625 362 227 0927 -042 -177 -311 -446 -581 -716 -85 6875 363 229 0939 -04 -176 -311 -445 -58 -715 -85 7125 365 23 0951 -039 -175 -31 -445 -58 -715 -85 7375 367 232 0964 -038 -174 -309 -444 -579 -715 -85 7625 368 233 0976 -037 -173 -308 -444 -579 -714 -85 7875 37 234 0989 -036 -172 -308 -443 -578 -714 -849 8125 371 236 1 -035 -171 -307 -442 -578 -714 -849 8375 373 237 101 -034 -17 -306 -442 -578 -713 -849 8625 375 239 103 -033 -169 -305 -441 -577 -713 -849 8875 376 24 104 -032 -168 -305 -441 -577 -713 -849 9125 378 241 105 -031 -168 -304 -44 -576 -712 -849 9375 379 243 106 -03 -167 -303 -439 -576 -712 -848 9625 381 244 107 -029 -166 -302 -439 -575 -712 -848 9875 382 245 109 -028 -165 -302 -438 -575 -712 -848 10125 384 246 11 -027 -164 -301 -438 -574 -711 -848 10375 385 248 111 -026 -163 -3 -437 -574 -711 -848 10625 386 249 112 -025 -163 -3 -437 -574 -711 -848 10875 387 25 113 -024 -162 -299 -436 -573 -711shy -848 11125 389 251 114 -023 -161 -298 -436 -573 -71 -848 11375 39 252 115 -022 -16 -298 -435 -573 -71 -847 11625 391 253 115 -022 -16 -297 -435 -572 -71 -847 11875 392 254 116 -021 -159 -297 -434 -572 -709 -847 12125 393 255 117 -02 -158 -296 -434 -572 -709 -847 12375 394 256 118 -019 -158 -296 -434 -571 -709 -847 12625 395 257 119 -019 -157 -295 -433 -571 -709 -847 12875 396 258 12 -018 -157 -295 -433 -571 -709 -847 13125 397 259 12 -017 -156 -294 -432 -57 -709 -847 13375 398 259 121 -017 -155 -294 -432 -57 -708 -847 13625 399 26 122 -016 -155 -293 -432 -57 -708 -846 13875 399 261 122 -016 -154 -293 -431 -57 -708 -846 14125 4 262 123 -015 -154 -292 -431 -569 -708 -846 14375 401 262 124 -015 -154 -292 -431 -569 -708 -846 14625 402 263 124 -014 -153 -292 -43 -569 -707 -846 14875 402 263 125 -014 -153 -291 -43 -569 -707 -846 15125 403 264 125 -013 -152 -291 -43 -569 -707 -846 15375 403 264 126 -013 -152 -291 -43 -568 -707 -846 15625 404 265 126 -012 -152 -291 -429 -568 -707 -846 15875 405 265 126 -012 -151 -29 -429 -568 -707 -846 16125 405 266 127 -012 -151 -29 -429 -568 -707 -846 16375 405 266 127 -011 -151 -29 -429 -568 -707 -846 16625 406 267 128 -011 -151 -29 -429 -568 -707 -846 16875 406 267 128 -011 -15 -289 -428 -568 -707 -845 17125 407 267 128 -01 -15 -289 -428 -567 -706 -845 17375 407 268 128 -01 -15 -289 -428 -567 -706 -845 17625 407 268 129 -01 -15 -289 -428 -567 -706 -845 17875 407 268 129 -01 -15 -289 -428 -567 -706 -845 18125 408 268 129 -01 -15 -289 -428 -567 -706 -845 18375 408 269 129 -01 -149 -289 -428 -567 -706 -845 18625 408 269 129 -001 -149 -288 -428 -567 -706 -845 18875 408 269 129 -001 -149 -288 -428 -567 -706 -845 19125 408 269 13 -001 -149 -288 -428 -567 -706 -845 19375 409 269 13 -001 -149 -288 -428 -567 -706 -845 19625 409 269 13 -001 -149 -288 -428 -567 -706 -845 19875 409 269 13 -001 -15 -288 -428 -567 -706 -845
114
FS Fresh Food Wan Simulation Output Including Anti-sweat Condenser Tube
INPUT PARAMETERS
Section Dimensions (mm) Hidth 4500 Length 2000 Depth 2960 Steel skin thickness 6500 Plastic skin thickness 2500
Mesh Geometry dx 2250 dy 2500 Number nodes in x-direction 20 Number nodes in y-direction 80 Number of steel skin nodes (including corner 00) 11 Steel nodes under the seal 2 to 10 Tube located at node 6
Steel skin conductivity (Him K) 5400 Foam insulation conductivity (Him K) 27000E-02 Plastic skin conductivity (Him K) 1500 Outside h (Hm2 K) 6870 Inside h (Hm2 K) 6700 Outside Temp (C) 2100 Inside Temp (C) 4000
OUPUT PARAMETERS
Number of iterations 602
10 Heat Flux Thru Hall (Hm2) 9132
Heat Transfer Along Metal Skin Under Seal node to node qm[Hm21 Qm[HI
2 3 -15052E+04 -2896 3 4 -15125E+04 -2910 4 5 -15198E+04 -2924 5 6 -15274E+04 -2939 6 7 3996 7688 7 8 3898 7500 8 9 3790 7292 9 10 3662 7045
Maximum difference () 1243
j qleft [HI qright [HI -1 -2957 7832 0 -92065E-02 -38838E-02 1 -77348E-02 -48044E-02 2 -51596E-02 -30284E-02 3 -32948E-02 -15188E-02 4 -1 9628E-02 -54201E-03 5 -98600E-03 16837E-03 6 -36442E-03 70ll8E-03 7 79586E-04 96757E-03 8 43478E-03 11452E-02 9 70118E-03 12340E-02 10 87877E-03 12340E-02
115
11 87879E-03 13228E-02 12 10564E-02 12340E-02 13 10564E-02 11452E-02 14 96759E-03 11452E-02 15 87877E-03 10564E-02 16 87879E-03 87877E-03 17 78999E-03 87877E-03 18 61238E-03 78999E-03 19 61240E-03 61237E-03 20 52359E-03 52358E-03 21 34598E-03 34598E-03 22 25719E-03 25717E-03 23 16838E-03 16839E-03 24 79586E-04 25 -98018E-04 26 -18681E-03 27 -27561E-03 28 -36442E-03 29 -54202E-03 30 -54202E-03 31 -7 1962E-03 32 -80842E-03 33 -8 9721E-03 34 -98602E-03 35 -10748E-02 36 -11636E-02 37 -12524E-02 38 -1 3412E-02 39 -1 4300E-02 40 -15188E-02 41 -1 5188E-02 42 -1 6076E-02 43 -16964E-02 44 -17852E-02 45 -1 7852E-02 46 -1 8740E-02 47 -19628E-02 48 -19628E-02 49 -19628E-02 50 -20516E-02 51 -21404E-02 52 -22292E-02 53 -22292E-02 54 -23180E-02 55 -23180E-02 56 -23180E-02 57 -24068E-02
79578E-04 -98018E-04 -1 8682E-03 -27561E-03 -45322E-03 -54202E-03 -71962E-03 -71962E-03 -8 9722E-03 -8 9722E-03 -10748E-02 -11636E-02 -12524E-02 -13412E-02 -14300E-02 -1 5188E-02 -16076E-02 -16964E-02 -16964E-02 -17852E-02 -18740E-02 -19628E-02 -20516E-02 -20516E-02 -21404E-02 -22292E-02 -22470E-02 -22381E-02 -22647E-02 -23358E-02 -23447E-02 -23802E-02 -24512E-02 -24690E-02
58 -23979E-02 -25223E-02 59 -24423E-02 60 -24246E-02 61 -24423E-02 62 -24779E-02 63 -25400E-02 64 -25400E-02 65 -25667E-02 66 -26199E-02 67 -26022E-02 68 -26111E-02 69 -26377E-02 70 -26022E-02 71 -26732E-02 72 -26821E-02 73 -26199E-02 74 -26643E-02
-25489E-02 -25755E-02 -25933E-02 -2 6199E-02 -26466E-02 -26643E-02 -26821E-02 -26910E-02 -27087E-02 -27265E-02 -27354E-02 -27443E-02 -27531E-02 -27620E-02 -27620E-02 -27709E-02
116
75 -26377E-02 -27709E-02 76 -26377E-02 -27709E-02 77 -26555E-02 -27709E-02 78 -26910E-02 -27620E-02 79 -26555E-02 -27620E-02
Qleft [ii] -3079 Qright [ii] 6756 Percent entering cabinet 1800
Fresh Food Nodal Temperatures (Condenser Tube)
x(mm) y(mm) 1125 3375 5625 7875 10125 12375 14625 16875 19125 21375
19875 126 1206 1154 1104 1055 1007 9608 9158 872 8294 19625 1259 1205 1153 1103 1054 1006 9602 9152 8715 8289 19375 1259 1205 1153 1102 1053 1006 9598 9149 8711 8285 19125 1259 1205 1153 1102 1053 1006 9596 9147 871 8284 18875 1259 1205 1153 1102 1053 1006 9596 9147 871 8284 18625 1259 1205 1153 1103 1054 1006 9599 915 8712 8286 18375 126 1206 1154 1103 1054 1007 9604 9154 8716 829 18125 1261 1207 1155 1104 1055 1007 9611 9161 8722 8295 17875 1263 1209 1156 1105 1056 1008 962 9169 873 8302 17625 1264 121 1158 1107 1058 101 9632 918 874 8311 17375 1266 1212 116 1109 1059 1011 9646 9193 8752 8322 17125 1269 1215 1162 1111 1061 1013 9663 9209 8766 8335 16875 1272 1217 1164 1113 1063 1015 9682 9226 8783 835 16625 1275 122 1167 1116 1066 1017 9704 9246 8801 8367 16375 1279 1224 117 1119 1069 102 9728 9269 8822 8386 16125 1282 1227 1174 1122 1072 1023 9755 9294 8845 8407 15875 1287 1231 1178 1126 1075 1026 9785 9322 887 843 15625 1292 1236 1182 113 1079 103 9818 9352 8898 8456 15375 1297 1241 1187 1134 1083 1034 9854 9385 8929 8484 15125 1302 1246 1192 1139 1088 1038 9892 9421 8962 8514 14875 1308 1252 1197 1144 1092 1042 9934 946 8998 8547 14625 1315 1258 1203 1149 1097 1047 9979 9502 9037 8583 14375 1322 1265 1209 1155 1103 1052 1003 9547 9078 8621 14125 1329 1272 1216 1162 1109 1058 1008 9595 9123 8662 13875 1337 1279 1223 1168 1115 1064 1014 9647 9171 8706 13625 1346 1287 1231 1176 1122 107 102 9703 9222 8753 13375 1355 1296 1239 1183 1129 1077 1026 9762 9277 8803 13125 1364 1305 1247 1191 1137 1084 1033 9824 9335 8856 12875 1374 1314 1256 12 1145 1092 104 9891 9396 8913 12625 1385 1325 1266 1209 1154 11 1047 9962 9462 8973 12375 1396 1335 1276 1219 1163 1109 1055 1004 9531 9037 12125 1408 1347 1287 1229 1173 1118 1064 1012 9605 9105 11875 1421 1359 1299 124 1183 1127 1073 102 9683 9176 11625 1434 1371 1311 1251 1194 1137 1082 1029 9765 9252 11375 1448 1385 1323 1263 1205 1148 1092 1038 9851 9332 11125 1462 1399 1336 1276 1217 1159 1103 1048 9943 9416 10875 1478 1413 135 1289 1229 1171 1114 1058 1004 9505 10625 1494 1429 1365 1303 1243 1184 1126 1069 1014 9598 10375 1511 1445 138 1318 1257 1197 1138 1081 1025 9696 10125 1528 1462 1397 1333 1271 121 1151 1093 1036 98 9875 1547 1479 1413 1349 1286 1225 1165 1106 1048 9908 9625 1566 1498 1431 1366 1302 124 1179 1119 106 1002
117
9375 1586 1517 145 1384 1319 1256 1194 1133 1073 1014 9125 1607 1537 1469 1402 1336 1272 1209 1147 1087 1027 8875 1629 1558 1489 1421 1355 129 1226 1163 1101 104 8625 1652 158 151 1441 1374 1308 1243 1179 1116 1054 8375 1676 1603 1532 1462 1394 1327 1261 1195 1131 1068 8125 17 1627 1555 1484 1415 1346 1279 1213 1148 1084 7875 1726 1652 1579 1507 1436 1367 1299 1231 1165 11 7625 1753 1678 1604 1531 1459 1389 1319 1251 1183 1116 7375 1781 1704 1629 1556 1483 1411 1341 1271 1202 1134 7125 1809 1732 1656 1581 1508 1435 1363 1292 1222 1152 6875 1839 1761 1684 1608 1533 146 1387 1314 1243 1172 6625 187 1791 1713 1636 156 1485 1411 1337 1264 1192 6375 1903 1823 1744 1666 1589 1512 1437 1362 1287 1214 6125 1936 1855 1775 1696 1618 1541 1464 1387 1312 1236 5875 197 1889 1808 1728 1649 157 1492 1414 1337 126 5625 2006 1923 1842 1761 1681 1601 1522 1443 1364 1285 5375 2043 196 1877 1795 1714 1633 1553 1473 1392 1312 5125 2081 1997 1914 1832 1749 1668 1586 1504 1422 134 4875 212 2036 1952 1869 1786 1704 1621 1538 1454 137 4625 2161 2076 1992 1909 1825 1741 1658 1573 1488 1403 4375 2203 2118 2034 195 1866 1782 1697 1611 1525 1437 4125 2246 2161 2077 1993 1909 1824 1738 1652 1564 1474 3875 229 2206 2123 2039 1955 1869 1783 1695 1606 1515 3625 2336 2253 217 2087 2003 1918 1831 1742 1651 1558 3375 2383 2302 222 2138 2055 197 1882 1793 1701 1606 3125 2432 2353 2273 2192 211 2026 1938 1848 1755 1658 2875 2482 2405 2328 225 217 2086 20 1909 1815 1715 2625 2533 2461 2387 2312 2234 2153 2067 1977 1881 178 2375 2586 2518 2449 2378 2304 2226 2142 2052 1955 1851 2125 264 2579 2516 2451 2381 2306 2225 2136 2039 1933 1875 2696 2642 2587 2529 2466 2396 2319 2232 2134 2026 1625 2753 2709 2664 2614 256 2497 2425 2341 2244 2133 1375 2811 278 2746 2708 2664 2611 2546 2468 2373 226 1125 2871 2854 2835 2811 278 2739 2685 2615 2524 2411 875 2932 2932 293 2923 2909 2885 2846 2787 2706 2595 625 2995 3014 3031 3045 3052 3049 3031 2989 2922 2824 375 3058 3098 3138 3175 3208 3234 3245 3223 3179 3109 125 3124 3185 3247 331 3373 3436 35 3483 3467 3451
x(mm) y(mm) 23625 25875 28125 30375 32625 34875 37125 39375 41625 43875
19875 7877 747 7071 6679 6294 5915 554 5168 4799 4432 19625 7872 7466 7067 6676 6291 5912 5538 5166 4798 4431 19375 7869 7463 7065 6674 6289 591 5536 5165 4797 443 19125 7868 7462 7063 6673 6288 591 5535 5165 4797 443 18875 7868 7462 7063 6673 6288 591 5535 5165 4796 443 18625 787 7463 7065 6674 6289 591 5536 5165 4797 443 18375 7873 7466 7067 6676 6291 5912 5537 5166 4797 443 18125 7878 747 7071 6679 6294 5914 5539 5167 4798 4431 17875 7884 7476 7076 6684 6298 5917 5542 5169 4799 4431 17625 7893 7483 7083 6689 6303 5921 5545 5172 4801 4432 17375 7903 7492 7091 6696 6309 5926 5549 5175 4803 4433 17125 7914 7503 71 6704 6316 5932 5553 5178 4806 4435 16875 7928 7515 7111 6714 6324 5939 5559 5182 4809 4436 16625 7943 7529 7123 6725 6333 5947 5565 5187 4812 4438 16375 796 7544 7137 6737 6343 5955 5572 5192 4815 444 16125 7979 7561 7152 675 6355 5965 558 5198 4819 4442
118
15875 8001 7581 7169 6765 6368 5976 5589 5205 4824 4445 15625 8024 7601 7188 6781 6382 5987 5598 5212 4829 4447 15375 8049 7624 7208 6799 6397 6 5608 522 4834 445 15125 8077 7649 723 6819 6414 6014 562 5229 484 4453 14875 8107 7676 7254 684 6432 603 5632 5238 4847 4457 14625 8139 7705 728 6862 6451 6046 5645 5248 4854 4461 14375 8174 7737 7308 6887 6472 6064 566 5259 4861 4465 14125 8211 777 7338 6913 6495 6083 5675 5271 4869 4469 13875 8251 7806 737 6941 6519 6103 5691 5283 4878 4474 13625 8294 7845 7405 6972 6545 6125 5709 5297 4887 4479 13375 834 7886 7441 7004 6573 6148 5728 5311 4897 4484 13125 8388 793 748 7038 6603 6173 5748 5326 4907 449 12875 844 7977 7522 7075 6634 62 5769 5343 4918 4496 12625 8495 8026 7566 7114 6668 6228 5792 536 493 4502 12375 8553 8079 7613 7155 6703 6258 5816 5378 4943 4509 12125 8615 8135 7663 7199 6741 6289 5842 5398 4956 4517 11875 868 8194 7716 7245 6781 6323 5869 5418 4971 4524 11625 8749 8256 7771 7294 6823 6358 5898 544 4986 4532 11375 8822 8322 783 7346 6868 6396 5928 5463 5002 4541 11125 8899 8392 7892 7401 6915 6435 596 5488 5018 455 10875 898 8465 7958 7458 6965 6477 5994 5514 5036 456 10625 9066 8542 8027 7519 7018 6521 6029 5541 5055 457 10375 9155 8624 81 7583 7073 6568 6067 557 5075 4581 10125 925 8709 8177 7651 7131 6617 6107 56 5095 4592 9875 9349 8799 8257 7722 7193 6669 6149 5632 5117 4604 9625 9454 8894 8342 7797 7257 6723 6193 5665 514 4617 9375 9564 8994 8431 7875 7325 678 6239 5701 5165 463 9125 9679 9098 8525 7958 7397 684 6288 5738 519 4644 8875 98 9208 8624 8045 7472 6904 6339 5777 5217 4659 8625 9927 9324 8727 8137 7551 6971 6393 5819 5246 4674 8375 1006 9445 8836 8233 7635 7041 645 5862 5276 4691 8125 102 9572 895 8334 7722 7115 651 5908 5307 4708 7875 1035 9706 907 844 7814 7192 6573 5956 5341 4726 7625 105 9846 9197 8552 7911 7274 664 6007 5376 4745 7375 1066 9994 933 867 8014 7361 671 6061 5413 4766 7125 1083 1015 947 8794 8121 7452 6784 6118 5452 4787 6875 1101 1031 9617 8925 8235 7548 6862 6178 5494 481 6625 112 1049 9773 9063 8356 765 6945 6241 5537 4834 6375 114 1067 9937 9209 8483 7757 7033 6308 5584 4859 6125 1161 1086 1011 9364 8618 7872 7126 638 5634 4887 5875 1183 1106 103 9528 8761 7993 7225 6456 5686 4916 5625 1207 1128 1049 9703 8914 8123 7331 6537 5743 4947 5375 1231 1151 107 9889 9076 8261 7443 6624 5803 498 5125 1258 1175 1092 1009 925 8409 7564 6717 5867 5015 4875 1286 1201 1116 103 9436 8567 7694 6816 5936 5053 4625 1316 1229 1142 1053 9637 8738 7833 6924 601 5094 4375 1349 1259 1169 1078 9853 8922 7983 7039 609 5138 4125 1384 1292 1199 1104 1009 912 8146 7164 6177 5186 3875 1422 1327 1231 1133 1034 9336 8321 7299 627 5237 3625 1463 1365 1266 1165 1062 957 8512 7445 637 5291 3375 1508 1407 1304 1199 1092 9824 8719 7603 6479 middot535 3125 1557 1453 1346 1237 1124 101 8943 7773 6595 5412 2875 1612 1504 1393 1278 116 104 9185 7956 6719 5478 2625 1673 1561 1444 1323 1199 1073 9446 8152 6851 5546 2375 1741 1624 1501 1373 1242 1108 9725 8359 6989 5617 2125 1818 1695 1565 1429 1289 1146 1002 8575 713 5687 1875 1906 1775 1636 149 1339 1186 1032 8792 727 5755 1625 2007 1868 1716 1556 1392 1227 1062 9001 7401 5818
119
1375 1125 875 625 375 125
2127 2271 2449 2679 2994 3436
1975 2103 226
2467 2776 3361
1807 1912 2032 2173 2333 2469
1629 1707 1788 1863 191
1868
1447 1501 1548 1575 1559 1454
1266 1301 1324 1324 1279 1163
109 1111 112
1107 1058 9548
9183 9311 934
9205 8813 8043
7514 7591 7611 7544 735
6956
5873 5918 5953 5988 6049 6199
F6 Freezer Wall Simulation Output Including Anti-sweat Condenser Tube
INPUT PARAMETERS
Section Dimensions (mm) Width Length Depth Steel skin thickness Plastic skin thickness
5600 2000 1580 6500 2500
Mesh Geometry dx dy Number nodes in x-direction Number nodes in y-direction Number of steel skin nodes (including corner 00) Steel nodes under the seal Tube located at node
2800 2500 20 80
11 2 to 10 6
Steel skin conductivity (Wm K)
Foam insulation conductivity (Wm K) Plastic skin conductivity (Wm K)
Outside h (Wm2 K) Inside h (Wm2 K) Outside Temp (C) Inside Temp (C)
5400 27000E-02 1500 6870 6410 2100 -1000
OUPUT PARAMETERS
Number of iterations 879
ID Heat Flux Thru Wall (Wm2) 1362
Heat Transfer Along Metal Skin Under Seal node to node qm[Wm2] Qm[W]
2 3 -15024E+04 -1543 3 4 -15111E+04 -1552 4 5 -15205E+04 -1562 5 6 -15310E+04 -1572 6 7 5828 5986 7 8 5690 5844 8 9 5535 5684 9 10 5348 5492
Maximum difference (Is) 1356
j qleft[W] qright[W] -1 -1566 5928
120
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63
0 -62085E-02 -31363E-02 -5 9522E-02 -40097E-02 -44286E-02 -30955E-02 -33621E-02 -21814E-02 -25242E-02 -1 4577E-02 -1 8767E-02 -9 6252E-03 -13815E-02 -58162E-03 -10387E-02 -31499E-03 -73398E-03 -1 6265E-03 -54353E-03 -10285E-04
-35309E-03 27805E-04 -23882E-03 65891E-04 -16265E-03 14208E-03 -1 24 55E-03 14207E-03 -48371E-04 14207E-03 -10285E-04 10398E-03 -10285E-04 10399E-03 -10281E-04 10398E-03 -48371E-04 65891E-04 -1 02 85E-04 27805E-04 -86465E-04 16377E-04 -48375E-04 -52182E-04 -86465E-04 -97886E-04 -1 2455E-03 -13979E-03 -1 7788E-03 -16645E-03 -19692E-03 -21597E-03 -24263E-03 -25786E-03 -30357E-03 -30357E-03 -33404E-03 -35309E-03 -3 7975E-03 -3 9879E-03 -41784E-03 -44450E-03 -45974E-03 -49402E-03 -50164E-03 -53592E-03 -54353E-03 -58162E-03 -58543E-03 -62733E-03 -62733E-03 -66923E-03 -66542E-03 -71493E-03 -70351E-03 -75303E-03 -74541E-03 -7 9111E-03 -77969E-03 -83301E-03 -81397E-03 -87491E-03 -85206E-03 -90919E-03 -88634E-03 -94728E-03 -92062E-03 -97775E-03 -95109E-03 -10158E-02 -98537E-03 -10463E-02 -1 0158E-02 -10768E-02 -1 04 63E-02 -11073E-02 -10692E-02 -11377E-02 -10996E-02 -11644E-02 -11225E-02 -1 1949E-02 -11492E-02 -12215E-02 -11758E-02 -12444E-02 -11949E-02 -12672E-02 -12177E-02 -12901E-02 -12368E-02 -13129E-02 -12596E-02 -1 3282E-02 -12748E-02 -1 351 OE-02 -1 2977E-02 -13701E-02 -13129E-02 -1 3853E-02 -13282E-02 -14005E-02 -1 3434E-02 -14158E-02 -13586E-02 -14310E-02 -1 3701E-02 -14463E-02
121
64 -1 3815E-02 -1 4577E-02 65 -1 392 9E-02 -14691E-02 66 -14005E-02 -14767E-02 67 -14120E-02 -14881E-02 68 -14196E-02 -14958E-02 69 -1 4272E-02 -15034E-02 70 -14310E-02 -15110E-02 71 -1 4386E-02 -1 5148E-02 72 -14424E-02 -15186E-02 73 -14463E-02 -15224E-02 74 -14501E-02 -1 5262E-02 75 -14501E-02 -1 5300E-02 76 -14539E-02 -15262E-02 77 -14539E-02 -15300E-02 78 -1 4539E-02 -15262E-02 79 -14501E-02 -1 5300E-02
Qleft [Wj -1653 Qright [Wj 5163 Percent entering cabinet 2380
Freezer Nodal Temperatures (Condenser Tube)
x(mm) y(mm) 14 42 70 98 126 154 182 210 238 266
19875 9606 8457 7334 6235 516 4107 3075 2064 107 00944 19625 9596 8448 7325 6227 5152 4099 3068 2056 1064 00882 19375 9591 8443 732 6222 5148 4095 3064 2053 106 00850 19125 9591 8443 732 6222 5147 4095 3064 2052 106 00847 18875 9596 8448 7325 6226 5151 4099 3067 2056 1063 00873 18625 9606 8457 7334 6235 5159 4106 3074 2062 1069 00928 18375 9621 8472 7347 6248 5171 4118 3085 2072 1078 01013 18125 9641 8491 7366 6265 5188 4133 3099 2085 109 01128 17875 9666 8514 7388 6287 5208 4152 3117 2102 1106 01272 17625 9696 8543 7416 6313 5233 4176 3139 2123 1125 01447 17375 9731 8577 7448 6343 5262 4203 3165 2147 1147 01652 17125 9772 8616 7485 6378 5295 4234 3194 2174 1173 01888 16875 9817 8659 7526 6418 5333 427 3228 2206 1202 02156 16625 9868 8708 7573 6462 5375 431 3265 224 1234 02455 16375 9924 8762 7624 6511 5421 4353 3306 2279 127 02786 16125 9985 8821 7681 6565 5472 4402 3352 2322 131 03149 15875 1005 8885 7742 6624 5528 4454 3401 2368 1353 03546 15625 1012 8954 7809 6687 5588 4511 3455 2418 1399 03976 15375 102 9029 7881 6755 5653 4573 3513 2472 145 04441 15125 1029 911 7958 6829 5723 4639 3575 253 1504 0494 14875 1038 9196 804 6907 5798 4709 3641 2592 1562 05474 14625 1047 9287 8128 6991 5877 4784 3712 2659 1623 06045 14375 1057 9385 8221 708 5962 4865 3787 2729 1689 06652 14125 1068 9488 832 7175 6052 495 3868 2804 1759 07297 13875 1079 9597 8424 7275 6147 504 3952 2884 1833 07981 13625 1091 9713 8535 738 6247 5135 4042 2968 1911 08704 13375 1104 9834 8651 7491 6353 5235 4136 3056 1993 09466 13125 1117 9962 8774 7608 6464 534 4236 315 208 1027 12875 1131 101 8902 7731 6581 5451 434 3248 2172 1112 12625 1146 1024 9037 786 6704 5568 445 3351 2268 1201 12375 1161 1038 9178 7995 6833 569 4566 3459 2369 1294
122
12125 1177 1054 9326 8136 6967 5818 4686 3572 2475 1392 11875 1194 107 9481 8284 7108 5951 4813 3691 2585 1494 11625 1211 1087 9642 8439 7256 6091 4945 3815 2701 1602 11375 1229 1104 981 86 7409 6237 5083 3945 2822 1714 11125 1248 1122 9985 8768 757 639 5227 4081 2949 1832 10875 1268 1141 1017 8943 7737 6549 5378 4222 3082 1954 10625 1288 1161 1036 9125 7911 6714 5534 437 322 2083 10375 1309 1181 1055 9314 8092 6887 5698 4524 3364 2217 10125 1331 1203 1076 9511 8281 7067 5868 4685 3514 2356 9875 1354 1225 1097 9716 8477 7254 6046 4852 3671 2502 9625 1378 1248 1119 9929 8681 7448 6231 5026 3835 2654 9375 1402 1271 1142 1015 8893 7651 6423 5208 4005 2813 9125 1428 1296 1166 1038 9113 7861 6623 5398 4183 2979 8875 1454 1321 1191 1062 9342 808 6832 5595 4369 3152 8625 1481 1348 1216 1086 9579 8308 7049 5801 4562 3333 8375 1509 1375 1243 1112 9826 8545 7275 6015 4764 3522 8125 1538 1403 127 1139 1008 8791 751 6238 4975 3719 7875 1568 1432 1299 1166 1035 9047 7755 6472 5196 3925 7625 1598 1462 1328 1195 1063 9314 8011 6715 5426 4142 7375 163 1494 1358 1224 1091 9591 8278 697 5667 4368 7125 1663 1526 139 1255 1121 9881 8556 7236 5919 4606 6875 1697 1559 1422 1287 1152 1018 8847 7514 6184 4855 6625 1731 1593 1456 132 1185 105 9151 7806 6462 5118 6375 1767 1629 1491 1355 1218 1083 9469 8113 6755 5394 6125 1804 1665 1527 139 1254 1117 9804 8435 7063 5686 5875 1842 1703 1565 1428 129 1153 1015 8774 7388 5995 5625 1881 1742 1604 1466 1329 1191 1052 9133 7732 6322 5375 1921 1782 1644 1507 1369 1231 1091 9511 8097 6669 5125 1962 1824 1686 1549 1411 1272 1133 9913 8485 7039 4875 2004 1867 173 1593 1455 1317 1176 1034 8899 7435 4625 2047 1912 1776 164 1502 1363 1223 108 9341 7859 4375 2092 1958 1823 1688 1552 1413 1272 1128 9816 8315 4125 2138 2005 1873 1739 1604 1466 1325 1181 1033 8807 3875 2184 2055 1925 1793 166 1523 1382 1238 1088 934 3625 2232 2106 1979 1851 1719 1584 1444 1299 1148 992 3375 2282 216 2037 1911 1783 1649 1511 1366 1214 1055 3125 2332 2215 2097 1976 1851 1721 1584 1439 1286 1125 2875 2384 2273 2161 2045 1925 1798 1663 152 1366 1202 2625 2436 2334 2229 212 2005 1883 1751 1609 1455 1288 2375 249 2397 2301 22 2093 1976 1849 1708 1554 1384 2125 2546 2463 2377 2287 2188 2079 1957 182 1666 1493 1875 2602 2532 2459 238 2293 2193 2079 1946 1793 16 17 1625 266 2605 2546 2482 2407 232 2215 2089 1939 176 1375 2719 2681 264 2592 2533 2461 2369 2253 2108 1928 1125 2779 2761 2739 271 2671 2618 2543 244 2305 2128 875 2841 2844 2844 2838 2822 2792 2739 2655 2535 2367 625 2903 293 2954 2974 2986 2984 2959 2899 2802 2658 375 2967 3018 3069 3117 316 3194 3209 3173 3108 3009 125 3032 3108 3186 3263 3342 3421 35 347 344 3412
x (nun) y (nun) 294 322 350 378 406 434 462 490 518 546
19875 -0865 -1811 -2743 -3663 -4573 -5474 -6368 -7257 -8141 -9022 19625 -0871 -1816 -2747 -3667 -4577 -5477 -6371 -7259 -8142 -9024 19375 -0874 -1819 -275 -3669 -4578 -5479 -6372 -726 -8143 -9024 19125 -0874 -1819 -275 -367 -4579 -5479 -6372 -726 -8144 -9025 18875 -0872 -1817 -2748 -3668 -4577 -5478 -6372 -7259 -8143 -9025
123
18625 -0867 -1812 -2744 -3664 -4574 -5476 -637 -7258 -8142 -9024 18375 -0859 -1805 -2738 -3659 -457 -5472 -6366 -7256 -8141 -9023 18125 -0848 -1796 -273 -3652 -4563 -5466 -6362 -7252 -8139 -9022 17875 -0835 -1784 -2719 -3642 -4555 -546 -6357 -7248 -8136 -9021 17625 -0819 -1769 -2706 -3631 -4546 -5451 -635 -7243 -8132 -9019 17375 -0800 -1752 -2691 -3618 -4534 -5442 -6342 -7237 -8128 -9017 17125 -0779 -1733 -2673 -3602 -4521 -5431 -6334 -7231 -8124 -9014 16875 -0754 -1711 -2654 -3585 -4506 -5418 -6323 -7223 -8119 -9012 16625 -0727 -1686 -2632 -3565 -4489 -5404 -6312 -7214 -8113 -9009 16375 -0697 -1659 -2607 -3544 -447 -5389 -6299 -7205 -8106 -9005 16125 -0664 -1629 -258 -352 -445 -5371 -6286 -7194 -8099 -9001 15875 -0627 -1596 -2551 -3494 -4428 -5353 -6271 -7183 -8091 -8997 15625 -0588 -156 -2519 -3466 -4404 -5332 -6254 -717 -8083 -8993 15375 -0545 -1522 -2484 -3436 -4377 -531 -6236 -7157 -8074 -8988 15125 -0500 -148 -2447 -3403 -4349 -5287 -6217 -7143 -8064 -8983 14875 -0451 -1436 -2408 -3368 -4319 -5261 -6197 -7127 -8053 -8977 14625 -0399 -1388 -2365 -3331 -4287 -5234 -6175 -7111 -8042 -8971 14375 -0343 -1338 -232 -3291 -4253 -5206 -6152 -7093 -803 -8965 14125 -0284 -1284 -2272 -3249 -4216 -5175 -6127 -7074 -8017 -8958 13875 -0221 -1228 -2221 -3204 -4177 -5143 -6101 -7054 -8004 -8951 13625 -0155 -1168 -2168 -3157 -4137 -5108 -6073 -7033 -7989 -8943 13375 -0085 -1104 -2111 -3107 -4093 -5072 -6044 -7011 -7974 -8935 13125 -0011 -1037 -2051 -3054 -4048 -5034 -6013 -6987 -7958 -8927 12875 0065 -0966 -1988 -2998 -4 -4993 -598 -6963 -7941 -8918 12625 01474 -0892 -1922 -294 -3949 -4951 -5946 -6937 -7924 -8909 12375 0233 -0815 -1852 -2878 -3896 -4906 -591 -6909 -7905 -8899 12125 03229 -0733 -1779 -2814 -384 -4859 -5872 -688 -7885 -8888 11875 0417 -0648 -1702 -2746 -3782 -481 -5832 -685 -7865 -8877 11625 05157 -0558 -1622 -2675 -372 -4758 -5791 -6819 -7843 -8866 11375 06189 -0464 -1537 -2601 -3656 -4704 -5747 -6785 -7821 -8854 11125 07269 -0366 -1449 -2523 -3589 -4648 -5701 -675 -7797 -8841 10875 08398 -0263 -1357 -2441 -3518 -4588 -5653 -6714 -7772 -8828 10625 09577 -0156 -126 -2356 -3444 -4526 -5603 -6676 -7746 -8814 10375 1081 -0044 -116 -2267 -3367 -4461 -555 -6636 -7718 -88 10125 121 00732 -1054 -2174 -3286 -4393 -5495 -6594 -769 -8785 9875 1344 01957 -0943 -2076 -3202 -4322 -5437 -655 -766 -8769 9625 1484 03238 -0828 -1974 -3113 -4247 -5377 -6504 -7628 -8752 9375 1631 04575 -0708 -1867 -302 -4169 -5314 -6456 -7596 -8734 9125 1784 05974 -0582 -1755 -2923 -4087 -5247 -6405 -7561 -8716 8875 1944 07436 -0450 -1638 -2822 -4001 -5178 -6352 -7525 -8697 8625 2111 08966 -0312 -1516 -2715 -3911 -5105 -6296 -7487 -8676 8375 2286 1057 -0167 -1387 -2604 -3817 -5028 -6238 -7447 -8655 8125 2469 1224 -0015 -1253 -2486 -3718 -4948 -6177 -7405 -8633 7875 2661 14 0143 -1111 -2363 -3614 -4863 -6112 -736 -8609 7625 2861 1584 031 -0962 -2234 -3504 -4774 -6044 -7314 -8584 7375 3072 1778 04856 -0806 -2097 -3389 -468 -5972 -7265 -8558 7125 3293 1982 06704 -0641 -1954 -3267 -4581 -5896 -7213 -853 6875 3526 2196 08652 -0467 -1802 -3138 -4476 -5816 -7158 -8501 6625 3771 2422 1071 -0283 -1641 -3002 -4366 -5732 -71 -847 6375 403 2661 1288 -0089 -1471 -2858 -4248 -5642 -7038 -8437 6125 4303 2914 1519 01168 -1291 -2705 -4124 -5547 -6973 -8402 5875 4593 3182 1763 03357 -11 -2542 -3991 -5445 -6904 -8365 5625 49 3467 2023 05686 -0896 -2369 -385 -5338 -683 -8326 5375 5227 3771 23 08169 -0678 -2185 -37 -5223 -6751 -8284 5125 5576 4095 2596 1082 -0446 -1988 -354 -5101 -6668 -8239 4875 5949 4442 2913 1366 -0198 -1778 -337 -4971 -6579 -8193 4625 635 4814 3254 167 00669 -1553 -3187 -4832 -6485 -8143 4375 6781 5215 3619 1997 03519 -1313 -2993 -4685 -6385 -809
124
4125 7246 5647 4014 2349 06577 -1055 -2785 -4528 -6279 -8036 3875 775 6116 444 2728 0986 -0780 -2565 -4362 -6168 -7978 3625 8299 6625 4902 3137 1339 -0486 -233 -4187 -6051 -7919 3375 8899 718 5404 3579 1717 -0173 -2082 -4003 -593 -7859 3125 9558 7787 595 4057 2122 01586 -1823 -3813 -5806 -7798 2875 1028 8455 6545 4573 2555 0508 -1553 -3618 -568 -7739 2625 1109 9192 7197 513 3014 0872 -1277 -3422 -5558 -7683 2375 12 1001 7912 5729 3497 1245 -1002 -3233 -5442 -7633 2125 1301 1093 8698 6373 3998 1618 -0739 -3059 -534 -7592 1875 1418 1196 9566 7058 4508 1975 -0503 -2914 -5262 -7564 1625 1552 1314 1053 778 5007 2292 -0319 -2818 -5218 -7554 1375 171 1452 116 8525 5462 2528 -0224 -2798 -5226 -7564 1125 19 1616 1281 9263 5815 2621 -0272 -2892 -5304 -7597 875 2136 182 1417 9928 5968 2477 -0537 -3151 -5478 -7651 625 244 2095 1569 1037 575 1953 -112 -3637 -5773 -7713 375 2845 2514 1726 1027 4873 0854 -2146 -4427 -6224 -7757 125 3384 3296 1814 8879 2904 -1057 -3745 -5602 -6885 -7725
F bull 7 Seal Simulation Source Code and Ouput
Program Seal
c This program simulates the heat transfer characteristics of an c idealized refrigerator door gasket The steady-state temperature c profile is determined numerically from a 2-D finite difference c code
cxxxxxxxxxxxxx Parameters and Variablesxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
integer NNNWnsurfijjlloopiters real emmissigmakhihoTiTodelsNN real depthareatolkair
parameter (N=6) parameter (NN=20) parameter (W=7) parameter (nsurf=4N-l) parameter (emmis=09) parameter (sigma=567e-8) parameter (k=03) parameter (kair=0026) parameter (hi=641) parameter (ho=687) parameter (Ti=1032) parameter (To=209) parameter (sNN=02) parameter (del=sNNNN) parameter (depth=10) parameter (area=deldepth) parameter (tol=10)
real x(Onsurf)y(Onsurf)len(ONOnsurf) real F(OnsurfOnsurf) real T(-lNN+lONN)radl(nsurf+l)rad(Onsurf) real Eb(Onsurf)bvector(nsurf+l)Amatrix(nsurf+lnsurf+l) real difasumqsumqtotqin(NN-l) real rlr2r3r4r5
125
real clc2c3c4c5c6c7
open (lfilemiddotGasketoutposition-rewind) open (2file=Gasket(q)outpositionmiddotrewind)
cxxxxxxxxxxxxx Determine Viewfactors xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
call Points(Ndelnsurfxy) call length(Ndelnsurfxylen) call Vfactor(NdelnsurflenF)
cxxxxxxxxxxxxx Resistors (C-m2W)
c Interior x- and y-directions rl=delk
c Exterior to outdoor ambient r2=1ho
c Exterior to indoor ambient r3-1hi
c Radiation r4=(1-emmis)emmis
c Air r5=delkair
xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
cxxxxxxxxxxxxx Guass-Siedel Iteration xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
c Begin massive loop to determine the steady-state temperature c distribution across the section First update the interior nodes c by considering the radiative heat transfer among the interior c surfaces The radiative transfer is updated by calling a routine c which computes the new radiosities every iteration Loop until c tolerance is met
c Initialize temperature field do 10 i=ONN
do 11 jONN T(ij)=50
11 continue 10 continue
do 15 j=ONN T(-1j)=250 T(NN+lj)=50
15 continue
c Set temperatures for row y=O and row y=NN do 20 i=ONN
T(iO)=fl(idel) T(iNN)=f2(idel)
20 continue
cxxxxxxxxxxxxx Begin Iteration xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
loop=l iters=l do while (loop eq 1)
c Update radiosities using new temps and update interior surface nodes
call Jsolver(FemmissigmaTNNNWnsurfradlradEb + bvectorAmatrix)
c interior corners cl=area (2rl) c2=arearl
126
c3=area (2rl) c4=arearl c5=arear4 c6=1(cl+c2+c3+c4)
T(WW)=c6(clT(W+lW)+c2T(W-lW)+c3T(WW+l)+ + c4T(WW-l)+c5(rad(0)-Eb(0raquo)
cl=arearl c2=area(2rl) c3=area(2rl) c4=arearl c5=arear4 c6-1(cl+c2+c3+c4) T(W+NW)=c6(clT(W+N+lW)+c2T(W+N-lW)+c3T(W+NW+l)+
+ c4T(W+NW-l)+c5(rad(N)-Eb(Nraquo) clarearl c2-area (2rl) c3-arearl c4=area(2rl) c5=arear4 c6=1(cl+c2+c3+c4) T(W+NW+N)=c6 (clT(W+N+lW+N)+c2T(W+N-lW+N) +c3T(W+NW+N+l)+
+ c4T(W+NW+N-l)+c5(rad(2N)-Eb(2Nraquo) cl=area(2rl) c2=arearl c3=arearl c4=area(2rl) c5=arear4 c6=1(cl+c2+c3+c4) T(WW+N)=c6 (clT(W+lW+N) +c2T(W-lW+N)+c3T(WW+N+l) +
+ c4T(WW+N-l)+c5(rad(3N)-Eb(3Nraquo)
c Interior surface y=W jl=l do 22 i=W+lW+N-l
cl=area(2rl) c2=area (2rl) c4=arearl c5=arear4 c7=arear5 c6=1(cl+c2+c4+c7) T(iW)=c6(clT(i+lW)+c2T(i-lW)+
+ c7T(iW+l)+c4T(iW-l)+c5(rad(jl)-Eb(jlraquo) jl=j1+1
22 continue
c Interior surface y=N+W jl=3N-l do 25 i=W+lW+N-l
cl=area(2rl) c2=area (2rl) c3=arearl c5=arear4 c7=arear5 c6=1(cl+c2+c3+c7) T(iW+N)=c6(clT(i+lW+N)+c2T(i-lW+N)+
+ c7T(iW+N-l)+c3T(iW+N+l)+c5(rad(jl)-Eb(jlraquo) jl=jl-l
25 continue
c interior surface x=W jl=4N-l do 30 j=W+lW+N-l
c2=arearl
127
c3=area (2rl) c4=area(2rl) c5-arear4 c7-arear5 c6-1(c2+c3+c4+c7) T(Wj)-c6(c7T(W+lj)+c2T(W-lj)+c3T(Wj+l)+
+ c4T(Wj-l)+c5(rad(jl)-Eb(jl))) jl=jl-l
30 continue
c interior surface x=W+N jl=N+l do 35 j-W+lW+N-l
cl=arearl c3=area(2rl) c4=area (2rl) c5-arear4 c7-arear5 c6-1(cl+c3+c4+c7) T(W+Nj)=c6(clT(W+N+lj)+c7T(W+N-lj)+c3T(W+Nj+l)+
+ c4T(W+Nj-l)+c5(rad(jl)-Eb(jl))) jl=j1+1
35 continue
c Interior air nodes do 37 j=W+lN+W-l
do 38 i=W+lN+W-l call sseqn(Tr5r5r5r5areaareaareaareaijNN)
38 continue 37 continue
c Solid nodes do 40 i=lNN-l
do 45 jlW-l call sseqn(TrlrlrlrlareaareaareaareaijNN)
45 continue do 50 j=W+N+lNN-l
call sseqn(TrlrlrlrlareaareaareaareaijNN) 50 continue 40 continue
do 55 j=WW+N do 60 i=lW-l
call sseqn(TrlrlrlrlareaareaareaareaijNN) 60 continue
do 65 i=W+N+lNN-l call sseqn(TrlrlrlrlareaareaareaareaijNN)
65 continue 55 continue
c Side boundaries do 70 j=lNN-l
call sseqn(Trlr2rlrlareaareaarea2area20jNN) call sseqn(Tr3rlrlrlareaareaarea2area2NNjNN)
70 continue
c Apply energy balance around the boundary of the gasket to determine c stopping criterium dif
dif-OO dif=dif+(area(2rl))(T(00)-T(01)) dif=dif+(area(2rl))(T(0NN)-T(0NN-l)) do 90 i=lNN-l
dif=dif+(arearl)(T(iO)-T(il)) dif=dif+(arearl)(T(iNN)-T(iNN-l))
128
90 continue dif=dif+(area(2r1raquo(T(NN0)-T(NN1raquo dif=dif+(area(2r1raquo(T(NNNN)-T(NNNN-1raquo
do 95 j=1NN-1 dif=dif+(arear2)(To-T(0jraquo dif-dif+(arear3)(Ti-T(NNjraquo
95 continue
print dif
c Stopping criterium if (dif It toll then
loop-O endif if (iters eq 10000) then
loop=O endif
iters=iters+1 end do
cxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx c Compute heat flux into the cabinet
qsum=OO asum=OO do 97 j=1NN-1
qin(j)=hiarea(T(NNj)-Ti) qsum=qsum+qin(j) asum=asum+area
97 continue qtot=qsumasum write(2) heat flux to interior [Wm2)qtot
do 100 j=NNO-l write(l) (T(ij)i=ONN)
100 continue
pause stop end
c----------------------------------------------------------------------shyc------~----------------------------------------------------------------
Subroutine Points(Ndelnsurfxy)
integer Nnsurfi real delincrx(Onsurf)y(Onsurf)
x(O)=OO y(0)=del2
c Points along y=O edge incr-OO do 10 i=lN
y(i)=OO x(i)=(del2)+incr incr=incr+del
10 continue
c Points along x=Ndel edge incr=OO do 20 i=N+12N
x(i)=Ndel
129
y(i)-(del2)+incr incr-incr+del
20 continue
c Points along y=Ndel edge incr=OO do 30 i=3N2N+l-1
y(i)-Ndel x(i)=(del2)+incr incr-incr+del
30 continue
c Points along x-O edge incr=OO do 40 i-nsurf3n+l-1
xli) -00 y(i)-laquo3del)2)+incr incr-incr+del
40 continue
return end
c----------------------------------------------------------------------shyc-----------------------------------------------------------------------
Subroutine length(Ndelnsurfxylen)
integer Nnsurfij real dellen(ONOnsurf)x(Onsurf)y(Onsurf)
c Special case surface 0 do 10 j=Onsurf
len(0j)=sqrtlaquox(0)-x(jraquo2+(y(0)-y(jraquo2) 10 continue
c Surfaces along y=O do 20 i=IN-l
do 30 j=Onsurf len(ij)=sqrtlaquox(i)-x(jraquo2+(y(i)-y(jraquo2)
30 continue 20 continue
c Special case surface N do 50 j=Onsurf
len(Nj)=sqrtlaquox(N)-x(jraquo2+(y(N)-y(jraquo2) 50 continue
return end
c----------------------------------------------------------------------shyc-----------------------------------------------------------------------
Subroutine Vfactor(NdelnsurflenF)
integer Nnsurfijjlj2 real dellen(ONOnsurf)F(OnsurfOnsurf)Lzero
c Determine viewfactors for special case of surface 0 Lzero=delsqrt(20) do 10 j=Onsurf
if (j eq 0) then F(Oj)=OO
elseif (j eq nsurf) then F(Oj)=(len(Oj)+len(10)-len(00)-len(ljraquo(2Lzero)
else F(0j)=(len(0j)+len(lj+l)-len(Oj+l)-len(ljraquo(2Lzero)
130
endif 10 continue
c Determine viewfactors for surfaces on edge y-O
do 20 i=IN-l do 30 j=Onsurf
if (i eq j) then F(ij)=OO
elseif (j eq nsurf) then F(ij)=(len(ij)+len(i+l0)-len(i0)-len(i+ljraquo(2de1)
else F(ij)=(len(ij)+len(i+lj+l)-len(ij+l)-len(i+ljraquo(2del)
endif sum=sum+F(ij)
30 continue 20 continue
c Determine viewfactors for all other surfaces do 40 iON-l
do 50 j=03N-l F(i+Nj+N)=F(ij)
50 continue do 60 j=3Nnsurf
F(i+Nj-3N)=F(ij) 60 continue
do 70 j=02N-1 F(i+2Nj+2N)=F(ij)
70 continue do 80 j=2Nnsurf
F(i+2Nj-2N)=F(ij) 80 continue
do 90 j=ON-l F(i+3Nj+3N)=F(ij)
90 continue do 100 j=Nnsurf
F(i+3Nj-N)=F(ij) 100 continue
40 continue
return end
c----------------------------------------------------------------------shyc-----------------------------------------------------------------------
Subroutine Jsolver(FemmissigmaTNNNWnsurfradlradEb + bvectorAmatrix)
integer NNNnsurfij real emmissigmaF(OnsurfOnsurf) real T(-INN+10NN)rad1(nsurf+l)rad(0nsurf) real Eb(0nsurf)bvector(nsurf+1)Amatrix(nsurf+lnsurf+l)surn
c Compute Eb for all surfaces do 10 i-ON-l
Eb(i)=sigma(T(i+WW) 4) Eb(i+N)=sigma(T(W+Ni+W)4)
10 continue incr=W+N do 20 i=0N-1
Eb(i+2N)=siqrna(T(incrW+N) 4) Eb(i+3N)=sigma(T(Wincr)4) incr=incr-1
20 continue
131
c Assign values to vector b do 30 i=Onsurf
bvector(i+l)-(emmis(l-emmisraquoEb(i) 30 continue
c Assign values to matrix A do 40 i-Onsurf
do SO j=Onsurf Amatrix(i+lj+l)--F(ij)
SO continue 40 continue
c Override diagonal terms do 60 i-Onsurf
sum-OO do 70 j-Onsurf
sum-sum+F(ij) 70 continue
Amatrix(i+li+l)-(emmis(l-emmisraquo+sum 60 continue
c Call routine to solve the set of equations for unknown JS call gaussy(Amatrixbvectorradlnsurf+l)
do 80 i=Onsurf rad(i)=radl(i+l)
80 continue
return end
c----------------------------------------------------------------------shyc-----------------------------------------------------------------------
Subroutine Gaussy(abxn) c
integer nkiimaxjkplusllplus real a(nn)b(n)x(n)amaxbtempatemp
+ aeon sum
do 28 k=l n amax=OO do 4 i=kn if(abs(a(ikraquo-abs(amaxraquo442
2 amax=a(ik) imax=i
4 continue if(abs(amax)-0le-15)101014
10 printO equations are not independent return
14 btemp=b(k) b(k)=b(imax) b(imax)=btemp do 18 j=kn
atemp=a(k j) a(kj)=a(imaxj)
18 a(imaxj)=atemp kplus=k+l if(k-n)222828
22 do 24 i=kplusn b(i)=b(i)-b(k)a(ik)a(kk) acon=a(ik) do 24 j=kn
24 a(ij)=a(ij)-a(kj)acona(kk) 28 continue
132
l=n 32 sum=OO
if(1-n)343838 34 lplus-1+1
do 36 j-lplusn 36 sum=sum+a(lj)x(j) 38 continue
x(l)-(b(l)-sum)a(ll) if(1-1)424240
40 1-1-1 goto 32
42 return end
c----------------------------------------------------------------------shyc-----------------------------------------------------------------------
Subroutine sseqn(TriplusriminusrjplusrjminusAiplus + AiminusAjplusAjminusijNN)
c This subroutine computes the temperature at node (ij) c given the temperatures of the surrounding nodes and c the resistances leading to these nodes
integer ijNN real T(-1NN+10NN)riplusriminusrjplusrjminus real AiplusAiminusAjplusAjminus real c1c2c3c4c5
c1=Aiplusriplus c2=Aiminusriminus c3=Ajplusrjplus c4=Ajminusrjminus c5=1(c1+c2+c3+c4)
T(ij)=c5(c1T(i+1j)+c2T(i-1j)+c3T(ij+1)+c4T(ij-1raquo
return end
c----------------------------------------------------------------------shyc----------------------------------------------------------------------shy
real function f1(x) c door BC
real x f1-18520 - 23413x
return end
c----------------------------------------------------------------------shyc----------------------------------------------------------------------shy
real function f2(x) c wall BC
real x f2=18128 - 3475x
return end
c----------------------------------------------------------------------shyc----------------------------------------------------------------------shy
133
Fresh Food Compartment Simulations Results
Run 1 The prescribed temperature profiles are
Wall 19203 - 1908 x Door 19203 - 1206 x
(x is in meters)
Outdoor Ambient = 210 degC Local Indoor Ambient = 1533 degC
Run 2 The prescribed temperature profiles are
Wall 18989 - 2024 x Door 19078 - 1326 x
(x is in meters)
Outdoor Ambient = 210 degC Local Indoor Ambient = 1496 degC
Run 3 The prescribed temperature profiles are
Wall 1895 - 1998 x Door 19053 - 1384 x
(x is in meters)
Outdoor Ambient = 208 degC Local Indoor Ambient = 1491 degC
Ayem~ Values Wall 1905 - 1977 x Door 1913 - 1384 x
(x is in meters)
Ave Outdoor Ambient = 209 degC Ave Local Indoor Ambient =1507 degC
Loss from Fresh Food == 10 W
134
Freezer Compartment Simulations Results
Run 1 The prescribed temperature profiles are
Wall 1821 - 343 x Door 18606 - 2354 x
(x is in meters)
Outdoor Ambient = 210 degC Local Indoor Ambient = 1029 degC
Run 2 The prescribed temperature profiles are
Wall 18182 - 3542 x Door 18544 - 2398 x
(x is in meters)
Outdoor Ambient = 210 degC Local Indoor Ambient = 1042 degC
Run 3 The prescribed temperature profiles are
Wall 17993 - 3452 x Door 18411 - 2272 x
(x is in meters)
Outdoor Ambient = 208 degC Local Indoor Ambient = 1024 degC
Ayera~e Values Wall 18128 - 3475 x Door 18520 - 23413 x
(x is in meters)
Ave Outdoor Ambient = 209 degC Ave Local Indoor Ambient = 1032 degC
Loss from Fresh Food = 157 W
135
LIST OF FIGURES (CONTINUED)
Page
C1 Location of Anti-sweat Devices and Overall Dimensions of Test Refrigerator 73
C2 Fresh Food Compartment Interior Dimensions 74 C3 Fresh Food Door75 C4 Freezer Interior Dimensions 76 C5 Freezer Door76
D1 Data Acquisition and Control System 78
E1 Steel Skin Temperature Plot for Fresh Food Compartment (Run 2) 79 E2 Steel Skin Temperature Plot for Fresh Food Compartment (Run 3) 80 E3 Steel Skin Temperature Plot for Freezer (Run 2) 80 E4 Steel Skin Temperature Plot for Freezer (Run 3) 81 E5 Mullion Temperature Profile Run 2 (Heater Off) 84 E6 Mullion Temperature Profile Run 3 (Heater Off) 85 E7 Mullion Temperature Profile Run 4 (Heater Off) 85 E8 Mullion Temperature Profile Run 5 (Heater Off) 86 E9 Mullion Temperature Profile Run 2 (CenterHeater On) 87 E10 Mullion Temperature Profile Run 3 (CenterHeater On) 88 E11 Mullion Temperature Profile Run 1 (LeftHeater On) 88 E12 Mullion Temperature Profile Run 2 (LeftHeater On) 89 E13 Mullion Temperature Profile Run 3 (LeftHeater On) 89 E14 Mullion Temperature Profile Run 1 (RightHeater On) 90 E15 Mullion Temperature Profile Run 2 (RightHeater On) 90 E16 Mullion Temperature Profile Run 3 (RightHeater On) 91
F1 Generic Nodal Resistor Network 92
IX
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I I I I I I I I I I I I I I I I I I I I I I
1 INTRODUCTION
New regulations recently announced by the Department ofEnergy call for substantial
energy efficiency increases for household appliances by 1993 The refrigerator is of
particular interest since it is the largest household consumer of electricity and accounts for a
large part of the 8 of the electricity used in the US for food-cooling both residential and
commercial In addition to efficiency standards regulations are being imposed on the use
of CFCs completely banning their use by the year 2000 (Braswell 1988)
The objective of this thesis is to present an analysis of all heat transfer paths from the
surroundings to the interior food compartments of the refrigerator under closed door
conditions Both experimental and numerical methods are used as a means to determine the
overall cabinet load as well as the load due to each pathway The study is focused on a
particular unit for practical purposes However the methods implemented may be applied
to any make or model to aid in the search for high efficiency cabinets
All loads determined in this study are strictly cabinet loads and not the loads seen by the
refrigerator system The thermal load on the cabinet is comprised of three main parts (i)
the load due to the one-dimensional heat transfer through the walls and doors to the food
compartments away froin the edges (ii) the load due to edge effects that is heat transfer
into the food storage compartments via paths around the perimeter of the cabinet aperture
and (iii) other miscellaneous sources
(11)
The determination of qlD is straightforward and is discussed in detail in Chapter 3 The
edge load must be broken down into several parts for examination
qedge = qwall + qdoor + qseal + qrnullon + qtubeave (12)
where
qwall heat input due to conduction along the wall steel flange
qdoo heat input due to conduction along the door steel flange
qseal heat conduction directly through the door seal
1
heat input due to conduction in the mullion region with the additional input from an anti-sweat heater
qtubeave heat input due to cabinet anti-sweat condenser tube averaged over the cycle time
heat input due to cabinet anti-sweat condenser tube
heat input due to conduction in the mullion region electric heater off
It is assumed that an electric anti-sweat heater in the mullion region is in use for the entire
cycle The test unit chosen for this study required this region to be heated almost
continually to eliminate condensation This load is represented by qmulloo in Eq (12)
The load qmulloff is due to heat conduction to the interior compartments at the mullion
region when the electric heater is off Although this value does not appear in the edge load
definition it is still important to detennine for sake of comparison with the value of
qmulloo The load due to the presence of an anti-sweat condenser loop around the aperture
of the cabinet is defmed as qtube Since this load is present for the on cycle only it must be
integrated over the cycle time to be included in Eq (12) hence the tenn qtubeave
The tenn qroisc is expressed as
qmisc = qfanave + qdefrostave + qcompave (13)
where
qfanave heat input from the evaporator fan averaged over the cycle time
qdefrostave heat input from the defrost heaters averaged over defrost cycle time
qcompave heat input from elevated exterior walls near the running compressor
Figure 11 is a cross sectional drawing of the door seal area of the test refrigerator
examined to detennine qwalI qdoor and~ The figure includes materials and their
properties taken from Incropera and Dewitt (1985)
2
400 ~I-I~ 065~
065 Only dimension that is different for the freezer
200
kltWIm-K)
Outer Steel Skin 540 312~ Polyurethane Wall Insulation 0027 0015- Inner Plastic Skin 015 009~
~ Rubber Gasket 03 017fm1I ~ ~ Glass Fiber Door Insulation 004 0023
All dimensions in millimeters
1 in= 254mm
Fig 11 Door Seal Region Cross Section
3
Figure 12 is a drawing of the mullion region cross section of the test refrigerator examined
to detennine ltlmullon and ltlmulloff
FREEZER
Freezer Gasket
Fresh Food Gasket
FRESH FOOD COMPARTMENT
Fig 12 Mullion Region Cross Section
The remainder of this thesis is devoted to the analysis of the closed door cabinet loads and
the experimental and numerical techniques used for their detennination
An experimental investigation of fumed silica as an alternative insulation for the refrigerator
is presented in Appendix A Although this appears to be a departure from the main topic
a relation exists The desire of higher efficiency requires a search for equal if not better
cabinet insulations that do not incorporate the use of ozone damaging CFCs Testing is
done to detennine the thennal conductivity and diffusivity of fumed silica for several
densities
4
2 LITERATURE REVIEW
The new energy standards imposed by the Department ofEnergy have sparked research in
the area of refrigerator efficiency and alternative refrigerants A study by Turiel and
Heydari (1988) focused on several ways to improve the efficiency of refrigerator-freezers
and freezers
Various classes for the study were chosen however the paper presents extensive results for
the most common variety a top-mounted automatic defrost refrigeratorfreezer The
design options considered were those changes that can be incorporated into the existing
refrigerator design Two types of improvements are noted (i) changes that increase energy
efficiency by decreasing the heat transfer into the cabinet and (ii) changes that increase the
efficiency by reducing auxiliary electricity use or improving the refrigeration system Type
(i) changes include Foam insulation substitution increased insulation thickness double
door gaskets improved foam insulation evacuated insulation panels and reduced heat load
of through-the-door feature Type (ii) changes include High efficiency compressor
substitution adaptive defrost fan and fan motor improvement anti-sweat heater switch
increased evaporator surface area hybrid evaporator enhanced heat transfer surfaces
mixed refrigerants improved expansion valve fluid control valve two-compressor system
use of natural convective currents and location of compressor condenser and evaporator
fan motor
Turiel and Heydari used a model developed by Little (1982) to carry out the energy use
simulations This model is a steady-state energy use simulation which computes the heat
leakage to the cabinet and then determines the energy needed to maintain the interior
ambient temperatures dictated by the OOE test procedure Turiel and Heydari present the
energy consumption figures for a 18 cubic foot top-mounted automatic defrost
refrigeratorfreezer as a baseline case They find that 74 of the total energy is accounted
for by the compressor 11 is for the anti-sweat heaters 10 is for the fans and 5 is
for the defrost heaters for a total of 947 kWhyr Also about 10 of the compressor
energy use is for the removal of internal heat generated by the evaporator fan motor defrost
heater and anti-sweat heaters
Several subsequent simulations were performed each time adding a design option that was
projected to improve efficiency The improvement levels were added cumulatively and
results were given on compressor run time heat leakage rate into the cabinet compressor
5
power demand at the operating point fan motor operating power for the evaporator and
condenser fans anti-sweat heater power and total daily and annual energy consumption
The goal here was to achieve by the last level of improvement the minimum energy
consumption that is technologically feasible One important fmding for all product classes
tested the highest efficiency was obtained by the use of evacuated panels in the planar
walls For example for the top-mounted automatic defrost unit the minimum energy use
was 515 kWyr
Finally an energy usevolume relation was developed from a linear regression obtained
from simulation results The resulting fit was shown as
Energy Use = Cl + C2Adjusted Volume
The constant Cl indicates the direct energy use to remove the cabinet loads associated with
the fan motors and heaters The slope C2 is an indicator of the rate of change ofenergy use
with a change in the adjusted volume This value reflects the rate of cabinet heat gain The
adjusted volume is the volume of the fresh food compartment plus 163 times the volume
of the freezer Turiel and Heydari produced a series of regressions for all of the defined
levels of design improvements allowing easy comparison at a specific adjusted volume
6
3 ONE-DIMENSIONAL WALL AND DOOR LOADS
In this section the overall steady cabinet load is calculated without considering the addition
of edge loading This load qlD is dermed as the heat transfer from the exterior
environment to the interior of the refrigerator under nonnal closed-door operating
conditions through four primary conductive paths (i) fresh food compartment walls (ii)
freezer walls (iii) fresh food door and (iv) freezer door In a later chapter the load due to
edge loading will be examined more closely
31 One-dimensional Heat Transfer Model
The steady conductive heat transfer through the walls of the refrigerator cabinet is
computed using a simple computer program written by Qausing (1983) This program
estimates inside and outside effective heat transfer coefficients using a flat plate natural
convection correlation Using these coefficients and the material properties and dimensions
of the wall insulation the one-dimensional heat transfer through the cabinet walls is
approximated for the fresh food and freezer compartments Figure 31 shows the
resistances and boundary conditions use in the model
Fig 31 Model Used To Calculate One-dimensional Load
7
The model provides flexibility for varying several parameters This allows application to
various types of refrigerator walls and doors Table 31 lists the input and output
parameters for the model The source code of the simulation along with the output for
completed runs are included in Appendix B
Table 31 One-dimensional Model Parameters
Input Parameters
To K (F) Room ambient temperature
Ti K (F) Interior ambient temperature
LiDs m (ft) WalVdoor insUlation thickness
kiDs Wm-K (Btuhr-ft-F) WalVdoor insulation thermal conductivity
A m2 (ft2) Cabinet surface area
Output
beo Wm2K (Btuhr-ft2_F) Exterior convective heat transfer coefficient
bei Wm2K (Btuhr-ft2-F) Interior convective heat transfer coefficient
hro Wm2K (Btuhr-ft2_F) Exterior effective radiative heat transfer coefficient
hri Wm2-K (Btuhr-ft2_F) Interior effective radiative heat transfer coefficient
qlD W (Btuhr) Heat transfer rate through specified section
32 Determination of Effective Heat Transfer Coefficients
The simulation developed automatically estimates the inside and outside effective heat
transfer coefficients This effective value is the sum of the convective and radiative
components which are defined below
The radiative heat transfer coefficients are computed iteratively using eqs (31) and (32)
assuming (i) gray walls at temperatures T wi or Two with emissivities poundi and Eo (ii) black
surroundings at Ti or To and (iii) walls can see surroundings only
(31)
(32)
8
The convective heat transfer coefficients are estimated from a flat plate natural convection
correlation developed by Clausing (1983) In the laminar regime (Ra lt 1()9) the Nusselt
number based on the film temperature is given by Eq (33)
NUf = 052 Ra4 (33)
For the turbulent regime (Ra ~ 109) the Nusselt number becomes
NUf = 009 Raf3 (34)
where in both cases
Tw+T_ Film temperature T f == 2
Lc == Vertical surface characteristic length g == Gravitational acceleration f3 == Thermal expansion coefficient v == Kinematic viscosity Tw == Vertical wall surface temperature T_ == Outsideinside ambient temperature
kf == Air thermal conductivity
The film temperature characteristic length Nusselt number and Rayleigh number will
have different values for the inside surface compared with the outside surface of the
cabinet Therefore the inside and outside convective heat transfer coefficients are
determined separately from eqs (35) and (36)
(35)
- NUfo kfohco - (36)Leo
9
33 Results
The four primary regions analyzed are (i) the fresh food compartment walls (ii) fresh food
door (iii) freezer walls and (iv) the freezer door The values for the input parameters
ltLins kins A) are taken from a full-size unit that is used for the experimental analysis
presented in Chapter 4 The room temperature is used for the model parameter To Also
the fresh food ambient Tee and the freezer ambient Tfz are substituted for Ti when
suitable in order to closely simulate real operating conditions The results are given in
Table 32
Table 32 Results From One-dimensional Load Analysis
Input
Section TooC eF)
Tj degC eF)
Lins m (ft)
kins Wm-K (Btuhr-ft-OF)
A m2 (fi2)
Fresh Food 21 4 0045 0027 242 Walls (698) (392) (0148) (0015) (2605)
Fresh Food 21 4 0040 0040 089 Door (698) (392) (0131) (0023) (958)
Freezer 21 -10 0056 0027 110 Walls (698) (-140) (0184) (0015) (1184)
Freezer 21 -10 0040 0040 034 Door (698) (-140) (0131) (0023) (366)
Output
Section hco Wm2-K cBtuhr-ft2-Fl
hro Wm2-K iJtuhr -ft2-Fgt
hci Wm2-K (Btuhr-ft2-F)
hri Wm2-K 1Btuhr-ft2-F)
qlD W (Btuhr)
Fresh Food 130 544 198 461 209 Walls (23) (96) (35) (81) (713)
Fresh Food 144 542 218 463 117 Door (25) (95) (38) (82) (399)
Freezer 143 542 226 397 143 Walls (25) (95) (39) (70) (488)
Freezer 164 538 259 400 81 Door (29) (94) (46) (70) (276)
herro =687 Wm2 K (121 Btulhr-ft2-OF) Total qlD =550 W herrrr = 670 Wm2 K (118 Btulhr-ft2_0F) (1876 Btuhr)
herrrz = 641 Wm2 K (113 Btulhr-ft2-OF)
The load for our operating conditions is 550 W (1876 Btuhr) Once again this quantity
does not reflect the total cabinet load on the refrigerator cabinet Edge effects are analyzed
in detail in the following chapters Another important result is the values for the effective
10
inside and outside heat transfer coefficients which are simply the sum of the convective
and radiative components The outside coefficient is heffo the fresh food coefficient is
heffff and the freezer coefficient is hefffz These numbers are used whenever film
coefficients are needed for computations
11
4 EXPERIMENT AL ANALYSIS
This section presents an experimental study performed on a full-size household
refrigerator In Chapter 3 we defined the load due to heat transfer through the walls and
doors of the cabinet as qlD The purpose of this experimental analysis is to quantify qwalh
qdoor qmulloff and Qrnullon and Qmisc Three types of tests are performed to accomplish
this task Descriptions of each are presented separately in the sections that follow
41 Temperature Profile Measurements
The refrigerator is instrumented with many thermocouples in various key areas to give
temperatures across the steel skin and to compare and verify the thermopile tests outlined
in the next section The four primary paths along the steel flange that are examined are the
wall-side fresh food door-side fresh food wall-side freezer and the door-side freezer
Five Type T 36 AWG thermocouples are placed along the skin for each path Figure 41
is a detailed drawing of the location of the thermocouples
Wall side TICs Door side TICs with 5 mm spacing with 5 mm spacing
Fig 41 Steel Skin Temperature Profile Thermocouple Placement
The wire leads are oriented so they run perpendicular to the temperature gradient so as to
reduce any effects of conduction along the wire to the bead The temperature data are fed to
the data acquisition system Each channel is a thermocouple input and is scanned at a rate
of 5 times a second The data are smoothed automatically by the software in blocks of 10
12
points for an average temperature every 2 seconds A full description of the data
acquisition and control system is provided in Appendix D
Data are collected for several runs to provide a good base to detennine average values since
the test conditions vary slightly from run to run To get a good measurement of the
temperature profIles along the steel flange the unit is shut off at the beginning of the run
and allowed to drift to quasi-steady conditions The presence of a large amount of thennal
mass (see Appendix C) within the refrigerator provides for a stable interior ambient
temperature during data collection The outer ambient is controlled by the room thennostat
which keeps the laboratory at a constant temperature to within plusmn1degC
Figure 42 is an example plot of a run that gives the temperature profIles along the steel
skin on the wall-side and door-side for the fresh food compartment
193
192
G 191 ~
i 19
middot5 189F
188
Run I iii --0 - Door Profile
~Imiddotmiddotmiddotmiddotmiddotmiddotmiddott 0 Wall Profue
i ~ i - - T =19273 - 001206x i i-- door i If ~
=-r~r==L~r=I ~ I +~~=~~~~~~~~~ middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot
Outdoor Ambient = 210 degC Fresh Food Ambient =48 degC
187-+----+----J------I----+---~
o 5 10 15 20 25
x (mm) 1 in= 254 mm
Fig 42 Steel Skin Temperature Plot for Fresh Food Compartment
The dashed line represents a linear least-squares fit for the door data and the solid line is the
corresponding fit for the cabinet wall data Each data point in the plot represents the
average temperature at that point over a period of time at quasi-steady conditions
Similarly Figure 43 is a plot of the temperature profIles for the freezer
13
186
184
a 182
~
i 18
5 178~
176
174
Run 1 t-- 1 1 --0 - Door Profde
P~P1 0 Wall Profile
- -LLl--=-+--shy- - Tdo = 18606 - O02354x i
or ~
=c==-rc1 1 ltb 1 ~
~~r--r- -r---shy0 5 10 15 20 25
x (mm) 1 in= 2S4mm
Fig 43 Steel Skin Temperature Plot for Freezer
A total of six separate runs were perfonned three for the fresh food compartment and three
for the freezer Plots for the other runs are located in Appendix E
From the figures above for the fresh food compartment the slope on the wall-side is
slightly steeper than the slope on the door-side In fact this trend is seen for all the runs
Therefore the heat conduction along the metal skin into the cabinet along the wall is
somewhat greater than that of the door For the freezer the slopes are nearly equal hence
the heat conduction along the wall skin and the door skin are nearly the same
42 Thermopile Testing
Another simple but important test is the use of a thennopile to measure the average
temperature difference at various locations on the steel flange regions of the unit Figure
44 is a schematic of the thennopile test set-up The thennopile is constructed from 36
AWG copperconstantan thennocouple wire
14
-
CopperConstan$t Junctions 285 mPt
IOmm
10mmThermopile
IOmm
Digital Multimeter
1 in= 254mm
Fig 44 Thermopile Test Apparatus
Five junctions are used for the fresh food compartment and three for the freezer The
junctions are mounted 10 mm (039 in) apart from one another along the steel skin beneath
the door seal Figure 45 is a detailed drawing of the lateral location of the thermopile
junctions
15
1 in =254 mm
Fig 45 Thermopile Placement
The thennopile provides an average temperature difference across the junctions The
output voltage must frrst be divided by the number of pairs of junctions and then translated
into a temperature difference using a referencing chart for the thennocouple wire Table
41 is a summary of the results from these tests The output voltages are read accurately to
within plusmn0002 mV The raw data and data reduction procedure are given in Appendix E
Table 41 Thermopile Output
Test Conditions Fresh Food aT Freezer aT TodegC
(OF) TffoC
(OF) Tfzoc
(OF) aTwallff degC
(Of) aTdoorffoc
(OFgt aTwallfzoC
(Of) aTdoorfzoC
(OFgt
1 210 (698)
48 (406)
-88 (162)
026 (047)
024 (043)
037 (067)
041 (074)
2 210 (698)
37 (387)
-87 (163)
027 (049)
026 (047)
038 (068)
040 (072)
3 208 (694)
37 (387)
-93 (153)
027 (049)
026 (047)
038 (068)
040 ( 072)
Average Values 209 (696)
40 (392)
-90 (158)
0267 (0481)
0253 (0455)
0377 (0679)
0403 (0725)
43 Thermocouple Drag Testing
One final technique applied is thennocouple drag testing This is a more qualitative method
to supply insight into what exactly is happening when the compressor is pumping wann
16
refrigerant through the anti-sweat tube that lines the perimeter of the cabinet aperture The
main objective of this test is not to give accurate temperature proftle infonnation but
instead to detennine the placement of the condenser tube This is needed as an input for
the numerical simulation of this region The reason that the temperature are not accurate is
the fact that the thermocouple is being dragged across a surface where good thermal contact
may not occur and significant energy may be generated Figure 46 is a schematic of the
apparatus used for drag testing
Power Supply
Data Acquisition System
Outer Metal Skin
Potentiometer
Inner Plastic Skin
Condenser Tube
Fig 46 Thermocouple Drag Test Apparatus
This device is quite simple yet very effective The type T 36 AWG thennocouple begins
at the interior boundary of the steel skin beneath the seal on the wall-side of the cabinet
The potentiometer is turned by hand moving the thennocouple oqtward along the skin
The temperature and location are stored simultaneously this way The thennocouple is kept
17
pressed against the steel flange by the seal The linear translation of the thennocouple is a
function of the output voltage Voutbull
s = 2mllT Vout (41)Yin
r =radius of potentiometer post =30 mm (012 in)
nT = total number of turns of potentiometer = 10
Vin = input voltage = 05 V
Vout = output voltage
Drag tests are run on the wall steel skin for both the fresh food compartment and the
freezer Runs are perfonned at four separate times the first being when the compressor
turns on Figure 47 is a plot of the drag proflles across the wall-side skin in the fresh food
compartment Figure 48 is a plot of the profiles in the freezer compartment The same
trends are generally seen for both regions The freezer profiles are simply shifted down in
temperature values as expected The temperature peak seems to move through time to
settle near the center of the flange region under the seal
31
30
29
G
i 28~
27
26~
25
24
23
e
Ji ~ i i i 1middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotlmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddoti~~
---l- Time 4
o Time 2 rr
i
0 5 10 15 20 x (mm)
Fig 47 Drag Profiles (Fresh Food)
18
26~--------+---------~-------4--------~
i ~
Time 1 24
22
20
18
16~~------+---------~-------4--------~
4 __
~~Time3
middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot_middotmiddot_middotmiddotimiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot
Outer Seal Edge o
o 5 10 15 20
x (mm)
Fig 48 Drag Profiles (Freezer)
44 Experimental Determination of qwall and qdoor
The results from the temperature profile and thennopile testing are used to detennine qwall
and qdoor according to the following defmitions
qwall = qwallff + qwallfz (42)
(43)
Where qwal1ff = heat conduction along wall-side fresh food compartment steel flange
qwallfz = heat conduction along wall-side freezer compartment steel flange
qdoorff = heat conduction along door-side fresh food compartment steel flange
qdoorfz = heat conduction along door-side freezer compartment steel flange
The trends derived from the fixed profiles exhibit generally good agreement with the
temperature differences seen by the thennopile For the fresh food compartment the
thennopile displays a slightly larger AT than what is seen in the profiles and both give a
19
slightly larger temperature difference for the wall-side compared with the door-side For
the freezer the temperature differences match closely on the wall-side however the doorshy
side AT is shown to be somewhat less than the wall-side AT for the fIXed thennocouple
measurements where the opposite is seen from the thennopile The worst discrepancy is
on the order of 10 and is probably due to the fact that the thennopile gives an average temperature difference at several vertical locations on the wall whereas the other method is
at one vertical location only
Since the thennopile produces an average temperature difference across the steel skin its
output is used to detennine the heat flux into the cabinet The refrigerator casing is being
used as a heat meter Thus the flux along the skin in the fresh food compartment on the
wall-side is
kmiddot ATwallffqwallff = m (44)
Ax
The load qwallJf is Eq (44) multiplied by the cross sectional area This area is the
thickness of the steel casing multiplied by the perimeter that is exposed to the room
ambient This perimeter varies for each of the two paths that comprise qwall and the two
paths that comprise qdoor The other cabinet loads are computed in a similar way and are
given in Table 42 The details of these values are given in Appendix E
Table 42 Experimental Determination of qwall and qdoor
Section Load W (BtuIhr)
qwallJf 28 (96)
qwallJz 21 (72)
qwall 49 (168)
qdoorff 33 (112)
qdoorJz 33
1112)
qdoor 66 (224)
20
45 Experimental Determination of qmulloff
The region that lies between the fresh food compartment and the freezer is called the
mullion The front portion of the mullion is covered by a thin steel face plate to provide a
suitable interface for the door seal magnets In this section the load due to heat conduction
along the mullion steel skin into the freezer and fresh food compartment is detennined
based on the experimental data
The heat transfer rate qmulloff is sum of two parts The first component is the heat
conduction along the steel plate into the fresh food compartment and the second is the
conduction into the freezer
qmulloff = qmulloffff + qmullofffz (45)
Figure 49 schematically illustrates paths of these two components
FREEZER
FRESH FOOD COMPARTMENT
Fig 49 Heat Flow Paths in Mullion
21
Ten 36 A WG type T thennocouples are mounted from top to bottom across the steel face
plate Figure 410 shows the cross section of the plate and the location and numbering of
the thennocouples
FREEZER
1bennocouplesSteel Face (5 mm spacing from
Plate bottom edge)
Freezer Gasket
Fresh Food Gasket
10 50
FRESH FOOD COMPARTMENT
1 in =254 mm
Fig 410 Mullion Face Plate Cross Section
Data are gathered from the ten thennocouples when the unit is shut off and allowed to drift
to a quasi-steady ambient temperature A total of five runs were perfonned Figure 411 is
a sample plot of the quasi-steady temperature profile All other plots are contained in
AppendixE
22
116
Run 1 I 115 ICcIIIII114 iii t ~mull~ =12~7 - 00~654xa
~ 113
rrfIIJ~~If112i 5 )mullfz 1= 1081~ + OOdl25X 111111 ~
11 oo+-t--t-iH-+-lo-shyiii i i Room Ambient = 2184 degc
109 middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1middot Fresh Ambient = 381 OC
108
1 10
I I I I I Freezer Ambient =-832 degc
2 3 4 5 6 7 8 9
TIC
Fig 411 Mullion Temperature Profile
The plot also shows two linear equations These represent linear fits to each side of the
peak temperature at TIC 7 The slopes (shown in degCmm) are used to detennine the heat
conduction to each compartment by eqs (46) and (47)
lmulloffff = km A (aT) (46)ax offff
qmul)offfz = km AIll) (47)ax offfz
The cross sectional area is the product of the face plate thickness (10 mm 0039 in) and
the length of the mullion (717 mm 2825 in) The average slopes from all five runs are
used to detennine qmulloffff and qroullofffz The results are given in Table 43
23
Table 43 Experimental Results from Mullion Analysis
Load W (Btuhr)
09qmullofUz (31)
07qmulloffff (24)
16qmuIlorr (55)
46 Experimental Determination of qmullon
In this section the load due to heat conduction along the mullion steel skin into the freezer
and fresh food compartment when an anti-sweat heater is on is experimentally determined
The test unit is equipped with an electric anti-sweat heater to eliminate condensation in the
mullion region The heater is installed on the back side of the plate and may be switched on
manually when needed It is a wire resistor type rated at 10 watts
The heat transfer rate qmullon is composed of two parts The first component is the heat
conduction along the steel plate into the fresh food compartment and the second is the
conduction into the freezer similar to ~ul1off
qmuIlon = ~ullonff + qmuIlonfz (48)
The location of the wire heater and the heat transfer paths are shown in Figure 412
24
FREEZER
qmullonfz
qmullonff
FRESH FOOD COMPARTMENT
Fig 412 Electric Heater Location
A series of tests are perfonned while the heater is on and the refrigerator is cycling
nonnally Three runs are done at each of three separate locations along the mullion
laterally (i) LEFT dermed as 180 mm (71 in) from the left-hand side of the unit (ii)
RIGHT 180 mm (71 in) from the right-hand side of the unit (iii) CENTER at center of
the mullion Figure 413 is a plot of the temperature profile across the face plate when the
heater is on for a specific test run The plots for all other runs are provided in Appendix E
The plot shows two profiles These represent the upper and lower limits as the unit cycles
The upper limit occurs just before the compressor turns on while the lower limit is at the
point in time just before the compressor shuts off At all times in between the profile
oscillates between the two limits maintaining nearly the same shape Once again a linear
fit is applied to the data on the fresh food side and the freezer side
25
30 iii imiddot iii i
29
28
27
Run 1
T mu
ill~~ 11 f = 26707 + 010776x Tmu11ff = 3128 - 00793x
Z +_ a 26~
I ~
middotmiddotmiddotbull-middotbullimiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotimiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotimiddotmiddotmiddotimiddotmiddot
24
25
e 23~ =H-T+H~i=i=
iimiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotimiddotmiddot T 11 ff = 27435 - 009504x 22 Tmullfz =21865 + 01l786x I m~ iii
21 -lmiddotmiddotmiddotmiddotmiddotmiddotmiddot-tmiddot Upper Limlt 0
20 middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotjmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotimiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddott 0 Lower Limit
19
0 1 2 3 4 5 6 7 8 9 10
TIC I
Fig 413 Mullion Temperature Profile With Heater On (Center)
Heat fluxes are computed identically to the method in Section 45 using the average slopes
from all nine runs The minimum value occurs just before to compressor turns on while
the maximum value occurs just before the compressor shuts off during normal cycling
The load is averaged over the cycle time which is approximately 50 for the test unit and
laboratory conditions The results are given in Table 44
Table 44 Experimental Results from Heater Analysis
Lower Profile Average W
(BtuIhr)
Upper Profile Average W
ffituhr)
qmullonfz 73
(249) 53
(181)
qmullonff 23 (78)
26 (89)
96 (32 7)
79 (270)
qmullon 88
300)
26
47 Determination of Qmisc
The load qoisc is comprised of three main parts The first is the load due to the evaporator
fan motor The fan that moves cool air in the cabinet also adds a thennalload Fans of this
type in use range from 8 - 16 watts The fan of our test unit is rated at 92 watts This
value must be integrated over the cycle time The cycle time for the unit is approximately
50 for the test conditions Thus the value of qfanave is 46 watts
The load qdefrostave is not determined experimentally Instead an estimate is obtained from
a similar study done by Turiel and Heydari (1988) This value is 5 watts which is an
average of the defrost heater input over the defrost cycle The defrost cycle can range from
10 - 12 hours of compressor run-time
The fmalload qcompave is detennined by measuring the cabinet surface temperature at the
region surrounding the compressor and computing the heat transfer locally The value is
found to be 2 watts Table 45 summarizes the results
Table 45 Miscellaneous Loads
Load W CBtuhr)
46 qfanave (15middotU
50 qdefrostave _07Ql
20 qcompave (68)
116 Qmisc (395)
27
s NUMERICAL SIMULATION
In this chapter a two-dimensional numerical model which is used to simulate the steadyshy
state heat transfer in the wall near the door seal is discussed The results from the model
include a computation of qwallff qwallfz and the complete temperature distribution across
the section The model is also used to estimate the additional cabinet load due to the
presence of an anti-sweat condenser tube embedded beneath the outer casing that runs
along the perimeter of the unit A separate model is presented which is used to simulate the
two-dimensional heat transfer across the door seal cross section The results are used to
determine qseal
51 Wall Model
A finite-difference technique is used to approximate the steady-state temperature
distribution in the wall section The technique is applied to solve the governing steady
two-dimensional heat conduction equation (assuming constant conductivity with no
generation)
(51)
Equation (52) is the basic fmite-difference representation of the conduction equation in a
homogeneous medium of constant conductivity with no heat generation (White 1988) In
Appendix F a complete list of all the model difference equations is provided
2(1+(3)Tij = (3Tij+l + Ti+lj+(3Tij-l + (3Ti-lj (52)
where (3 = (llxlly)2
28
Figure 51 is a sketch of the model representation of the refrigerator wall at the door seal region The dimensions shown are flexible parameters in the model The model allows for
slight changes in the geometry as well as changes in mesh size in both x and y directions
However the mesh size must remain uniform across the section
s5 s6
sl
Fig 51 Wall Heat Conduction Model Sketch
For each of N unknown nodal temperatures N simultaneous linear algebraic equations are obtained for N unknowns If N is large as is the case for this simulation an iterative
technique is preferred to solve the system ofequations A Fortran program has been
written to carry out the finite-difference iteration A copy of the code is given in Appendix
F A simple Guass-Seidel technique is employed for the differencing iteration At each
iteration an energy balance is done for the entire section In theory this balance should be
29
zero (heat entering) = (heat leaving) The iteration is continued until the difference
between heat entering and heat leaving is equal to 1 of the total heat entering the section
Table 51 defines the input parameters for the simulation
Table 51 Wall Simulation Input
Code Parameter Definition
To C (F) Exterior surrounding ambient temperature
Ti C (F) Interior ambient temperature
lan Wm-K (Btuhr-ft-F) Steel skin conductivity
kp Wm-K (Btuhr-ft-F) Plastic skin conductivity
kins Wm-K (Btuhr-ft-F) Wall insulation conductivity
heffo Wm2-K (Btuhr-ft2-F) Outside effective heat transfer coefficient
hefti Wm2-K (Btuhr-ft2-F) Inside effective heat transfer coefficient
dm mm (in) Steel skin thickness
dp mm (in) Plastic skin thickness
dx mm (in) Mesh size x direction
dy mm (in) Meshsizeydirection
sl mm (in) Wall width
s2 mm (in) Wall length
b mm (in) Effective Perimeter
s3 mm (in) Seal indentation
s4 mm (in) Seal width
s5 mm (in) Depth of steel skin into cabinet along seal boundary
s6 mm (in) Width of plastic skin along seal boundary
The model assumes that the boundary that lies along the door seal is adiabatic This allows
the separation of the wall section from the rest of the geometry in this region The seal and
door can then be treated separately later A simple calculation is done to validate this
assumption
30
Steel Skin (Refrigerator wall)
Seal (k = 02 Wm-K)
Fig 52 Non-adiabatic Door Seal
A 2 degC temperature difference AT is imposed across the seal This is a slight overshy
estimate based on the experimental data An estimate of the conductive heat flux is
determined from Eq (53)
ATqerror=k- (53) Ax
qrror =02 Wm-C o~Cm =20 Wm2
The heat flux ql for the fresh food compartment is determined in Appendix E to be 14418
Wm2 Therefore qerror represents approximately 13 of the total flux Hence this
term is neglected in this study
Two other possible sources of error are associated with the fmite-difference technique itself
(Ozisik 1980) The fIrSt is called truncation error and arises from the discretization of the
second-order derivative in the steady conduction equation The second is referred to as the
round-offerror which is due to the fact that numerical calculations are carried out only to a
finite number of decimal places Repeated solution with smaller increments shows that the
truncation error is negligible The precision of the energy balance is evidence that the
round-off errors are negligible
31
S2 Wall Simulation to Determine qwall
The finite-difference model is used to detennine the wall-side heat transfer along the steel
skin However more valuable information is yielded from the simulation The nodal
temperature distribution is detennined which gives insight into the direction and magnitude
of heat fluxes throughout the section The fresh food compartment and the freezer are both
simulated to detennine qwallff and qwallJz respectively Table 52 is the list of the values
used for the model input parameters for both cases
Table S2
Code Parameter
To C eF)
Ti C eF)
kIn Wm-K (Btuhr-ft-F)
kp Wm-K (Btuhr-ft-F)
kins Wm-K (Btulhr-ft-F)
heffo Wm2-K (Btuhr-ft2_F)
heffi Wm2-K (Btuhr-ft2-F)
dm mm (in)
dp mm (in)
dx mm (in)
dy mm (in)
sl mm (in)
s2 mm (in)
b mm (in)
s3 mm (in)
s4 mm (in)
s5 mm (in)
s6 mm (in)
Input Values
Fresh Food 210 (698) 40
(392) 540 (312) 015 (009) 0027 0015t 687 (121) 670 (118) 065
(0026) 25
(0098) 225
(0088) 25
(0098) 450
(1772) 2000 (7874) 2960
(11653) 225
(0088) 2025 (0797) 225
(0886) 2025 (0797)
32
Freezer 210 (698) -10
(140) 540middot (312) 015 (009) 0027 (0015) 687 (121) 641 (113) 065
(0026) 25
(0098) 28
(0088) 25
Jo098) 540
(2125) 2000 (7874) 1580
(6220) 28
(0110) 196
JO772) 224
(088t) 288
(1134)
The output from the simulation includes the entire nodal temperature field heat fluxes at
each node along the centerline heat fluxes from node to node along the steel skin beneath
the door seal and the value for qwallff and qwallcz These heat transfer values and the
nodal temperature distribution are listed in Appendix F
The quantities qwallff and qwallcz are determined by computing the heat fluxes from node to node along the centerline of the section subtracting the one-dimensional flux and then
multiplying by the cross sectional area for that node and summing to give the total heat
transfer rate The primary results are shown in Table 53
Table 53 Wall Simulation Results
Section
The temperature distributions are shown in the following two figures Figure 53 shows
the temperature contour for the fresh food results Figure 54 is the same plot for the
freezer results
Since the geometry of the refrigerator door is similar to that of the wall along the edges the
heat leakage to the food compartments along the door flange can be approximated as being
roughly the same as qwall This approximation of qdoor is a good means of estimating the
two prime contributors to the edge loss for various different refrigerators which may have
slightly different geometries as well as different material properties
33
i
3875
3625
TemplaquogtC)
-e
11111
20
18
16 3375
g 3125 14 -5 2875 ~ 122625 ~
2375~ 102125~
1875 8
1625
1375 6
1125
875 4
625
375
SteeVPlastic Liner Interface
Fig 53 Fresh Food Wall Temperature Distribution
34
i 4875
4625
4375
4125
3875
3625
3375 -
3125e g 2875
2625 ~ 2375 ~ 2125c (I)
1875 ~ 1625
1375
1125
875
625
375
125
Fig 54 Freezer Wall Temperature Distribution
Temp(OC)
20
15
10
5
0
-5
-10
35
53 Wall Edge Simulation to Determine qtube
The wall simulation is modified to include a constant temperature node placed beneath the
steel flange to represent the presence of an anti-sweat condenser tube The simulation is
perfonned for the specific conditions that are typical of the test unit as well as a range of
lateral tube locations For the test refrigerator the tube is located as shown in Figure 55
and is at 35degC (95 OJlt)
Outer Steel Skin
14625 mm 1
Inner Plastic Liner
Fig 55 Tube Location for Simulation
The quantity qtube is detennined by taking the fluxes along the vertical line to the left of
the tube subtracting the one-dimensional flux and then multiplying by the cross sectional
area for that node and summing to give the total heat transfer rate Again the fresh food
compartment and the freezer must be simulated separately to produce a total governed by
Eq (54)
(54)
Program output for the fresh food and freezer simulations is given in Appendix F Table
54 summarizes the results from the model
Table 54 Wall With Condenser Tube Simulation Results
Section Load W iBtubrl
qtubeff 46
(157)
qtubefz 28 (96)
qtube 74 (253)
qtube8ve (ave for 50 cycle time)
37 (126)
36
-I i c IJ
~
r 4875
4625
4375
4125
3875
3625
3375
3125
2875
2625
2375
2125
1875
1625
1375
1125
875
625
375
125
TempfC)
SteeVPlastic Liner Interface
35
30
25
20
15
10
5
Fig 56 Fresh Food Wall Temperature Distribution Including Warm Anti-sweat Tube
37
TempfC)4875
4625
4375
4125
3875
3625
3375 - 31258
2875g 2625fo 2375
3 2125 d vI 1875
~ 1625
1375
1125
875
625
375
125
SteeVPlastic Liner Interface
Fig 57 Freezer Wall Temperature Distribution Including Warm Anti-sweat Tube
38
40
30
20
10
0
-10
The heat fluxes at each node along the vertical line to the left of the tube are also computed
by the simulation This value quantifies the amount of heat that is moving toward the outer
boundary and is used to determine the percentage of heat entering the cabinet For the test
refrigerator this value is 18 for the fresh food compartment and 24 for the freezer
Several more simulation runs were done to find the effect of lateral placement of the tube on
the overall heat transfer and the percentage of heat entering Figure 58 and Figure 59
show the trends that are found
-~ a tUbe ~middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotlmiddotmiddotmiddot=middotmiddot=pmiddotmiddotmiddot=middot-1- =1
middot middot middoti middot middotmiddotmiddotmiddotmiddotmiddotmiddotmiddot bull middotmiddotmiddot i middotmiddotmiddotmiddot middotmiddot middotmiddot ~ middotmiddot
middotmiddotrmiddot-rmiddot 0 lwbeff middotlmiddotmiddot~middot Gmiddottmiddotmiddot9middotlmiddot
i i -0- lwbe i middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotimiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddot fz tmiddotEimiddotmiddot ~G- -~ -q- -
0 5 10 15 20 25 x(mm)
Fig 58 Load Due to Condenser Tube for Various Tube Placements
8
~ - 7
50
a 6
~ 5
~ en 4 ~
pound ~ 3
2
- 26
~ a 24
middots bO
pound 22c ~
~ 20
a = 18sect ~
16 0 5 10 15 20 25
x (mm)
Fig 59 Percentage of Heat Entering Cabinet for Various Tube Placements
39
54 Door Seal Simulation to Determine qseal
Another model is developed for the two-dimensional heat transfer through the door seal
This model is very similar to the one created for the wall section Once again a fIniteshy
difference technique is utilized to detennine the temperature distribution at steady-state
conditions Even though the cross sectional geometry of the seal is simplifIed to a square
with a hollow square with a centrally located cavity no closed-form solution can be
applied Therefore a simulation is needed
The fInite-difference representation of the two-dimensional steady Eq (55) using central
differencing is given by Ozisik (1980)
Ti-lj - 2Tij + Ti+lj + Tij-l - 2Tij + Tij+l = 0 (55) Ax2 Ay2
For this model a square mesh is applied reducing Eq (55) to
Ti-lj + Ti+lj + Tij-l + Tij+l - 4Tij = 0 (56)
x
Fig S10 Seal Simulation Mesh Layout
40
The nodes along the vertical surfaces at x=O and x=20 are subject to the convective
boundary conditions and governed by Eq (57) and Eq (58) respectively
2~xheffol 2~heffo2Ti+lj + Tij-l + Tij+l - (4 + k TiJ = - k To (57)
seal seal
2~heffffl 2~heffff2Ti-lj + Tij-l + TiJ+l - (4 + kseal Tij = - kseal Tff (58)
The nodes along the top and bottom outside surfaces are held at the prescribed temperature
profIles which are detennined from experimental data (see Section 41) The interior nodes
are subject to radiant e~change among themselves and conduction through what is assumed
to be stagnant air A closer look at the model of the hollow interior of the seal is shown in
Figure 511
Fig 511 Seal Cavity Mesh Details
Each interior node corresponds to a single gray surface with assumed emissivity of 09
Viewfactors for all surfaces are computed automatically before the iteration begins For
each iteration the effect of radiation within the enclosure is taken into account by updating
surface radiosities Jij Thus for nodes on interior surfaces an extra tenn is added to the
governing difference equation (Eb is the blackbody radiation)
41
~(J - Eb )1-pound IJ lj
A code written in Fortran is used to perfonn Guass-Seidel iteration of the difference
equations to compute the temperature distribution at mesh nodes (Code listing in Appendix
F) Once again convergence is based on an energy balance applied to the entire section
The iteration is continued until the difference between heat entering and heat leaving is
equal to 01 of the total heat entering the section Table 55 lists the input parameters
used in the model The fresh food compartment and the freezer compartment are simulated
separately
Table 55 Seal Simulation Input
Code Parameter Fresh Food Freezer
Number of nodes along outside edge 20 20
Number of nodes along inside edge 6 6 1 1Lx = fly mm (in) (0039) (0039)
210 210Outdoor ambient temperature degC (oF) (698) (698) 150 105Indoor local ambient temperature degC COF) 590J j509)
Outdoor heat transfer coefficient W m2-K 687 687 (121) (121)(Btuhr-ft2-F)
Indoor heat transfer coefficient Wm2-K 670 641 (118) (113)(Btuhr-ft2-F)
Gasket interior surface emissivity 09 09 03 03Gasket conductivity Wm-K (Btuhr-ft-F) (0173) (0173)
Wall-side Temperature Boundary 1905 - 1977x 1813 - 3475x Condition degC Door-side Temperature Boundary 1913 - 1384x 1852 - 2341x Condition degC
42
The load results are summarized in Table 56 below The program output is listed in
AppendixF
Table 56 Seal Simulation Results
Load W Section (BtuIhr)
10 Qsealff (34)
ljQsealfz (Sn
25qseal (85)
The steady-state temperature distribution is shown in the figures below Figure 512 is the
fresh food simulation and Figure 512 is the freezer simulation The direction of the heat
flow through the section is easily seen from these plots
43
Wall-side Boundary Temperature (C)
~~
I 20
195
i 19t 0
8 ~ 1859 -- ~
isis ~ ampJ gtshy 18 ~
11 ~ S ~ 175~
~ 17
165
x(mm)
Door-side Boundary
Fig 512 Seal Temperature Distribution (Fresh Food)
44
Wall-side Boundary Temperature (C)
Ii 19
185
18i f IQ 5 IQ
175-is-is I s 17j ~
5e 0C= 165
~ ~ 16
155
x(mm)
Door-side Boundary
Fig 513 Seal Temperature Distribution (Freezer)
45
6 DISCUSSION OF RESULTS
The heat transfer values detennined from the experimental analysis and the numerical
simulations are the various components that embody the cabinet load on the refrigerator It
is important to separate cabinet loads from system loads The system load can be thought
of as the total electrical energy consumption of the unit It has four basic components (i)
the compressor (ii) fans (iii) anti-sweat heaters and (iv) defrost heaters The first two
components the compressor and fans are the cost of removing heat from the cabinet This
amount of heat is equal to the cabinet load divided by the COP of the system The typical
energy consumption is shown schematically in Figure 61
System Load (Energy Consumption)
Defrost Heater (averaged over time
cycles every 10-12 hours of compressorrurt-time)
TuneCycle
Fig 61 Refrigerator System Load Graph
In a study done by Turiel and Heydari (1988) the compressor and fans accounted for 84
of the total system load for an 180 cubic foot top-mounted refrigerator Staley (1992)
found this value to be 86 for a similar unit Both of these studies used system analysis to
determine these numbers The energy consumption of the components were monitored
during operation The energy consumption of our test refrigerator can be determined in a
reverse manner from the cabinet load data If a COP of 1 is assumed the test refrigerator
46
compressor and fans accounts for 86 of the energy consumption to cool the cabinet This
compares favorably with the fmdings of Turiel and Heydari (1988) and Staley (1992)
Figure 62 is a schematic of the cabinet loads One possible load that is not included in the
figure is the heat input associated with the defrost drain tube that runs through the back
wall However this term is probably small relative to the other contributors
Cabinet Load
qseal qdoor
qwall
qmullon
qdefrostave
Fig 62 Cabinet Loads Graph
All the loads are determined in this study from either experimental measurements
numerical simulations or both Most of the loads are quasi-steady that is they do not
fluctuate significantly over the cycle time of the refrigerator There are four loads shown in
Figure 61 that are cyclical in nature The three loads that appear only while the
compressor is running are qcomp qfarb and qtube Also the refrigerator is subjected to a
load every time ice build-up is removed by the defrost heaters This load is averaged over
its own cycle time and shown in the graph as qdefrostave
47
61 Comparison of Simulation Results with Experimental nata
The majority of the cabinet loads are detennined from experimental data with the exception
of qseal and qtube The wall and door flange loads aremiddot also found from the numerical
simulation (see Chapter 5) The two-dimensional model detennines the wall-side heat
transfer along the steel skin into the food compartments No model is available to directly
detennine the heat transfer on the door-side However since the flange geometry on the
door-side is similar to the wall the value for qwall is considered to be a good estimate for
qdoor Table 61 gives these values determined from experimental measurements and the
simulation
Table 61 Comparison of Simulation and Experimental Values for qwall and qdoor
Experimental Result W Simulation Result W (BtuIhr) (BtuIhr)
qwallff 28 (96)
28 (96)
qwallz 21 (72)
27 (92)
qwall 49 (168)
55 (188)
ldoorff 33
(112) 28 (96)
qdoorfz 33
(112) 27 (92)
qdoor 66 (224)
55 (188)
The model predicts qwall to within 57 of the experimental value The agreement of the
estimate of qdoor with the experimental value is within 90
Some of the shortcomings in the model used in this investigation are
(i) Only the wall is modeled Ideally the entire region should be considered including the
door and seal (see Figure 11)
(ii) The flange geometry is simplified The steel casing skin in the flange region may bend
in more complex ways Also the plastic liner varies in thickness near the door seal
(iii) The mesh must be unifonn There is no means to vary how fme the mesh can be The
ideal situation would be to have a fine mesh near the edges and a course mesh far from the
seal
48
62 Mullion Analysis
The single largest edg~ load is found in the mullion section (329 of qedge and 94 of
qtol) This load is due to the electric anti-sweat heater installed on the backside of the face
plate The heater is rated at 10 watts and approximately 88 of that input enters the
interior of the cabinet as a thennalload This is probably due to the small surface area
exposed to the room and the low amount of convective heat transfer in the channel between
the fresh food and freezer doors With the heater on 88 watts is measured enter the food
chambers With the heater off only 16 watts enters the interior The addition of the
heater increases the mullion load 55 times Generally it is not necessary to use the
mullion heater at all times However for the test environment the heater nearly all the time
to eliminate sweating under the laboratory conditions
63 Seal Analysis
The heat conduction directly through the seal accounts for the smallest portion of the edge
loss (94 ofqedge and 27 of qtol) The numerical model to detennine these values uses
a simplified representation of the complex cross sectional geometry of an actual door seal
The various air pockets are reduced to a single hollow void There is no experimental data
to verify the model However the numbers and trends resulting from the simulation are
reasonable
64 Anti-sweat Condenser Tube Analysis
Thennocouple drag tests were perfonned to give insight into the nature of the temperature
profIles at the wall steel flange with the presence of an anti-sweat condenser tube The wall
heat transfer simulation model was modified to include the effect of this tube The heat
conduction to the interior increased by 76 at the wall flange region The amount of
additional loading due to the tube depends on several parameters location of the tube
temperature of the circulating refrigerant and local wall geometry Although the model is
flexible enough to handle vari01~S temperatures and limited geometrical changes only the
influence of tube position was investigated As the tube is moved towards the interior the
load increases For the test refrigerator about 20 of the heat flow was directed to the
interior compartments primarily along the steel skin
49
6S Overall Cabinet Load
The overall cabinet load is defined as a sum of three parts
(61)
The edge load is
qedge = qwall + qdoor + Qseal + Qrnullon + qtubeave (62)
where
qwall
qtubeave
heat input due to the conduction along the wall steel flange
heat input due to the conduction along the door steel flange
heat conduction directly through the door seal
heat input due to conduction in the mullion region with the additional input from anti-sweat heater
heat input due to cabinet anti-sweat condenser tube averaged over the cycle time
heat input due to cabinet anti-sweat condenser tube
qmulloff heat input due to conduction in the mullion region electric heater off
The terms of Qrnisc are defined as
qmisc = qfanave + qdefrostave + qcompave (63)
where
qfanave heat input from the evaporator fan averaged over the cycle time
qdefrostave heat input from the defrost heaters averaged over defrost cycle time
qcompave heat input from elevated exterior walls near the running compressor
Table 62 presents the overall cabinet load analysis results
50
Table 62 Overall Cabinet Loads
Load W Load Btuhr Total
qlD 550 1876 591
qedge 265 903 285
Qwall 49155 167 188 53
Qdoor 66155 2251 188 71
Qseal 25 85 27
Qmullon 88 300 94
Qtubl ngt 37 126 40
qmisc 116 395 124
Qfanave 46 157 49
Qdefrost ave 50 170 54
qcomoave 20 68 21
qtot 931 3174 100
Simulation Results
All loads are detennined experimentally with the exception oflsea1 and qtubeave The
values for qwall and qdoor are detennined from both experimental data and numerical
simulations Edge loss per unit length along fresh food perimeter is 29 Wm (30 Btuhrshy
ft) the loss per unit length along the freezer perimeter is 44 Wm (46 Btuhr-ft) and the
loss along the mullion section is 123 Wm (128 Btuhr-ft) with the heater on and 22 Wm
(23 Btuhr-ft) with anti-sweat heater off
The largest single load is the one-dimensional conduction through the walls and doors
The edge load comprises 285 of the total a significant portion The largest edge load is
due to the electric anti-sweat heater that is installed in the mullion section The smallest
edge load is due to the heat conduction through the fresh food and freezer door seals The
losses at the wall-side and door-side flange regions account for 53 and 71 of the total
load respectively These could be considered together since the pathway of heat transfer is
very similar If that were the case the sum of qwall and qdoor would be the second largest
contributor to the overall cabinet load The influence of an anti-sweat condenser tube is
reflected in the value of qtubeave Although this additional load is larger than qwall it must
be integrated over the refrigeration cycle timewhich is 50 of the cycle time for the test
unit The tube boosts the heat transfer along the wall flange by 76
51
To round out the cabinet load three miscellaneous loads are considered The evaporator
fan motor produces a heat load within the cabinet which is considered to be equal to the
power rating of the fan The automatic defrost feature is another thermal load that is
cyclical appearing about every ten to twelve hours of compressor runtime The fmalload
is due to the elevated exterior skin temperature near the compressor when it is running All
three of these loads are averaged over their cycle times for comparison with other quasishy
steady loads As a total qmisc represents 124 of the overall cabinet load
Opportunities to decrease the one-dimensionalload are available The emphasis has been to
develop super-insulations to be installed in the refrigerators Some being considered are
vacuum panels aerogels and vacuum packed powder insulations The disadvantages of
this improvement lies within the need to develop a cost-effective technique for fabricating
and installing such technologies compatible with high-volume manufacturing Also edge
losses and panel connection losses must be minimized due to the difficulty in making a
panel the size of refrigerator interiors Reliability of the seal and perfonnance of the outer
envelope need to be ensured over a long period of time ie the expected life of the
product
The possibilities of reducing the loads along the edge of the refrigerator aperture are
somewhat less apparent One method of reducing quasi-steady heat conduction along wall
and door flanges is to raise the inside cabinet wall temperature by minimizing interior film
surface heat transfer coefficients This could be accomplished by the use of low-emissivity
surfaces on the interior walls or on sections nearest the edges The need for an anti-sweat
device for the perimeter is also eliminated supplying a two-fold savings by reducing the
cabinet ioad and the system energy consumption The need for an electric mullion heater
might also be done away with by the same means The drawback again would be to make
such modifications acceptable and cost-effective for manufacture
The remaining miscellaneous loads provide some chance for improvement If the
efficiency of the fans is increased the energy use of the refrigerator can be reduced The
option of moving the fan motor outside the cabinet leads to other problems The motor
shaft must pierce the wall providing another path for heat leakage Also frost built-up on
the shaft would be a costly and difficult problem to eliminate If the compressor and
condenser were located near the top of the refrigerator they can operate more efficiently
Heat can be more readily convected away eliminating the need for the condenser fan
(Turiel and Heydari 1988) Frost fonnation in the freezer varies significantly depending
52
on the ambient conditions and the freezer usage The defrost cycle could be made more
energy efficient with the addition of adaptive controls All of these improvements would
require redesign of the product and the manufacturing process This is a very expensive
alternative which would need to be justified by the associated energy savings
53
7 SUMMARY OF CONCLUSIONS
The following is a list of the important findings produced from this study
(i) The edge loading accounts for a significant portion of the total cabinet load For the
test unit used in this study an 18 cubic foot top-mount refrigerator this load was
approximately 30 of the total load The load includes losses along the wall and door
flanges conduction through the door seal mullion loading with an electric anti-sweat
heater on and additional thennal input from an anti-sweat perimeter condenser tube
(ii) The presence of an electric anti-sweat mullion heater boosts the mullion loading by
a factor of approximately 5
(iii) The presence of an anti-sweat condenser tube around the perimeter of the refrigerator
increases the wall flange load by approximately 75
(iv) The presence of the door air damt reduces the temperature difference across the door
seal to 35 of the temperature difference between the interior and exterior
environments
(v) The hypothetical elimination of the additional load due to the electric anti-sweat
mullion heater reduces the edge loading to approximately 22 of the total cabinet
load
(vi) The hypothetical elimination of the load due to the anti-sweat condenser tube reduces
the edge loading to approximately 25 of the total cabinet load Ifboth anti-sweat
devices were not needed the edge loading would be further reduced to only 17 of
the total
(vii) During the course of this investigation it was concluded that the experimental and
numerical methods developed are applicable to most refrigeratorfreezers that are
produced today
t The portion of the door liner that extends into the cabinet along the wall
54
REFERENCES
Braswell A 1988 Impact of CFC Regulations on the Air Conditioning and Refrigeration Industry International Jow-nal ofRefrigeration Vol 11 No6 p 385
Cabot Corporation 1987 CAB-O-SIL Fumed Silica Properties and Functions Tuscola n pp 12-15
Clausing A M 1983 Natural Convection Correlations for Vertical Surfaces Including Influences of Variable Properties ASME Jow-nal ofHeat Transfer Vol 105 No 1 pp 138-143
Incropera FP and Dewitt DP 1985 Fundamentals ofHeat and Mass Transfer Second Edition John Wiley and Sons New York
Ingersoll LR Zobel OJ and Ingersoll AC 1954 Heat Conduction with Engineering and Geological Applications McGraw-Hill Book Company New York
Little AD Inc 1982 Refrigerator and Freezer Computer Model Users Guide Cambridge Massachusettes
Micropore International Ltd Microtherm Thermal Insulation Worcestershire England Section 1
Nix GH Lowery GW Vachon RI and Tanger GE 1967 Direct Determination of Thermal Diffusivity and Conductivity with a Refined Line-Source Technique Progress in Astronautics and Aeronautics (Vol 20) Thermophysics ofSpacecraft an Planetary Bodies Academic Press New York pp 865-878
Nix GH Vachon RI Lowery GW and McCurry TA 1968 The Line-Source Method Procedure and Iterative Scheme for Combined Determination of Conductivity and Diffusivity Thermal Conductivity Proceeding of8th Conference
Ozisik MN 1980 Heat Conduction Wiley-Interscience Publishing New York pp 486-487
Staley D 1992 Personal Communication Graduate Research Assistant University of Illinois Urbana
Turiel I Heydari A 1988 Analysis of Design Options to Improve the Efficiency of Refrigerator-Freezers and Freezers ASH RAE Transactions Vol 94 Part 2
Van der Held EFM and Van Drunen FG 1949 Physika Vol 15 No 10 p 865
White PM 1988 Heat and Mass TranSer Addison-Wesley Publishing Reading Mass pp 145-160
55
APPENDIX A FUMED SILICA INVESTIGATION
A ~ 1 Introduction
Fumed silica is a micro-porous powder comprised of submicron particles of amorphous
silica bonded together in a cellular structure Several grades of silica are available offering
a selection ofdifferent grain sizes and chemical treatments Fumed silica is commonly used
to provide thickening thixotropy suspension and other related properties in liquid
systems In dry systems it is used to promote free flow frictionizing and anti-blocking
properties Thus it is a versatile additive in materials such as inks coatings adhesives~
and silicon rubber (Cabot Corporation 1987)
The thermal insulating properties of this material have been somewhat less widely applied
however fumed silica as an insulation displays some interesting properties Fumed silica
insulations are commercially available and have become a more popular material for certain
specific applications In this section the results of an investigation of the thermal
properties of one type of fumed silica is presented
A2 Thermal Properties
As an insulator fumed silica uses the microporous principle to reduce thermal conduction
to the theoretically lowest possible levels (Micropore International Ltd 1988) Most
conventional insulations rely upon voids normally occupied bj alt aS the meanS ot
minimizing heat transfer through the material Therefore it is important to maintain these
voids for maximum insulation Fumed silica is comprised of tiny spheres with diameters
of the same order of magnitude as the mean free path of the molecules in the air
Therefore when these spheres are packed closely together gaseous conduction and
convection are minimized The cell size is sufficiently small to keep convective currents
from forming and to trap gas molecules to rebound elastically thereby not imparting their
energy to slower moving molecules In addition solid conduction is minimized by the fact
that silica is a material with intrinsically low thermal conductivity These unique properties
make fumed silica an attraCtive alternative to conventional insulations
56
A3 Experimental Method
Thennal conductivity and thennal diffusivity are the properties detennined from our
experimental study Many methods exist for establishing the thennal properties of a given
substance Both steady-state and transient procedures are available The hot-wire method
is a the transient procedure used in this study
The practical form of the hot-wire method is given by Van derHeldand Van Dronen
(1949) who used it to detennine conductivities of liquids Nix et al (1967) elaborated to
give a method for the simultaneous detennination of both thennal conductivity and thennal
diffusivity Therefore it is possible to detennine both conductivity and diffusivity by
passing a known amount ofcmrent through a heater wire embedded in the test material and
recording the temperature at a point on the wire and at a fixed point from the wire over the
period of the test From the temperature history of the point contiguous to the hot-wire the
conductivity can be detennined directly From the temperature history of the point at a
fixed distance from the hot-wire the diffusivity may be computed Both procedures are
outlined in the following section
A4 Theory
The temperature at any point in an infinite solid containing a line heat source of constantshy
rate is a function of the position time from initiation the thennal conductivity of the
material and the magnitude of the source This is shown mathematically by Ingersoll et aI
(1954) The cylindrical temperature field is expressed as
T=~l- exp-x2) dx (Al)21tk x
II
In series fonn
(A2)T=~[-amp-lnp+L-L+L_ ]21tk 2 21 4middot2 63
57
where
q = Heat input per unit length of wire [W1m]
k = Thennal conductivity of the material [Wm-K]
a = Thennal diffusivity of the material [m2s]
t = Elapsed time from heat liberation [s]
r = Radial distance from line-source [m]
Ce = Eulers constant (05772157 )
The temperature change between two times tl and t2 is accurate to better than one percent if
the value of ~ is less than 016 for a point very close to the line-source
(A3)
Equation (A3) is used in this case to detennine the thennal conductivity since the
diffusivity a and the radial distance T no longer appear in the relation Therefore
knowing the temperature at two different times during the test gives the conductivity
directly given that the value of ~ remains small This is achieved by choosing a point very
near if not contiguous to the hot-wire itself In our study a graphical method is used to
detennine the conductivity If the temperature versus the natural logarithm of the time is
plotted a straight line should be seen whose slope is equal to q4nk
Once the conductivity of the material is detennined the diffusivity can be found by the
method proposed by Nix et aI (1968) The temperature at a fixed and known distance
from the hot-wire must be monitored over the time period of the test Now since ~ gt 016
the diffusivity does not drop out of Equation (A2) Rewriting Equation (A3) as
(A4)
where
~2 ~4 ~6 ]r(~)= [ -~-ln~+---+-- (A5) 2 211 4middot2 6middot3
58
therefore (A6)
Using the temperature at the fixed location as an input Equation (A6) can be solved iteratively by means of Newton-Raphson technique to find the parameter ~ and thereby
yielding the thermal diffusivity a
AS Test Apparatus
Figure A1 is a sketch of the test apparatus used to collect thermal property data This
device provides a wide range of silica densities for packed tests Each half of the apparatus
is packed separately to the same density and then pressed together sandwiching the heater
wirethermocouple assembly between them
Remove bottom plate and press together with right half
Insert heater wirethermocouple assembl)
Remove bottom plate and press together with left half
Compact both halves to same density
Fig AI Fumed Silica Test Apparatus
Prior to loading the unpacked silica into the test cylinders the mass is carefully recorded
Each test cylinder has graduated marks to allow the volume of the sample to be computed
The density is then computed from the measured mass and volume At higher densities it
59
is sometimes necessary to load and compact several times Figure A2 is a schematic of the
heater wirethermocouple assembly and the entire test facility
Switch
Ammeter
Power Source
Cylindrical Test Section
Thermocouple for Conductivity
Data Acquisition System
Thermocouple for Diffusivity
Fig A2 Fumed Silica Test Facility Schematic
The heater wire used for all tests is 30 A WG nichrome wire with a nominal resistance of 2214 Wm Both thermocouples are type T 36 A WG Once the test sample is in place
the switch is closed allowing cUITent to pass through the heater wire The heat input per
unit length of the wire is determined from
(A7)
where q = Heat input per unit length of wire [Wm]
I = The input cUITent [Amps]
R = Heater wire resistance per unit length [Wm]
60
Knowing the heat input per unit length the temperature contiguous to the heater wire and
the temperature at a fixed distance from the heater wire over the duration of the test eqs
(A3) and (A6) can be solved This yields the conductivity and diffusivity respectively
A6 Results
All results presented in this section are from tests petfonned with a material sample donated
by Cabot Corporations Cab-O-Sil Division The silica is an untreated sample EH-5 with
a bulk density of 25 Ibsft3 and a nominal particle diameter of 70 angstroms Several tests
are petfonned at various densities The thermal conductivity is determined graphically as described above while the diffusivity is determined using a Fortran code to pe~orm the
Newton-Raphson iteration also outlined in Section A4
A total of seven different bulk densities are tested Each test consists of three runs at three
different power levels The temperature history is recorded for both thermocouples
Figure A3 is a plot of the temperature for the duration of a typical test for unpacked silica
70~--~----+----r----~-----~----+----r
10001
middot middot middot o 05 Ampsmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddot o 04 Ampsi ~ i
I i I I i oo~ct 60 IIJatr-T50
1 LL~40
1 ~ 1 010 1 ltgtom
JPi i30 i 0I1 o 03 Amps 1 I I
20~--~----+----r----~-----~----+----r
-10 o 10 20 30 40 50 60 70 Time (sec)
Fig A3 Time vs Temperature for Unpacked Run
61
To graphically detennine the thennal conductivity the temperatme data must be plotted
against the natural logarithm of time Figure A4 gives this plot along with the equations
that represent linear curve-fits to the straight portion of each curve
70~----~--------+------+--------~----~----~--------+-----~
60 ~ =l-LL-~--o T ~ 86839 ~ 1376 ~(t) I
50 ---f--H-deg--tfjtshy ~ T =11108 + 97346 m(t)
40 IT_oroJ~-
30 middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotImiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotsectmiddotmiddotmiddotmiddotmiddotImiddotmiddotmiddotmiddotmiddotmiddotmiddot~middotmiddotmiddotmiddot109~~Q9 T= 18431~ + 493 ~(t) 0
~ e i i i
20~----~--------+------+--------~---------~~----+------r
05 1 15 2 25 3 35 4 45 In (time)
Fig A4 Natural Log Time vs Temperature for Unpacked Run
All three curves should yield the same conductivity for the sample The conductivity is
detennined from the following relation
k= 12R (A8)4n(slope)
Table AI gives the average conductivity for each density level This is the average for the
three input cmrents used These results are also shown graphically in Figure A5
62
Table AI A verage Fumed Silica Conductivity for Various Bulk Densities
est
1
2
3
4
5
6
7
0024
0023
0022 -~ ct 0021
~ e 002
~
0019
0018
0017
i
~i
I I I I Imiddotmiddotmiddot_middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotimiddot_middotmiddot middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotimiddot-middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot
1i111
~ ~ iii
_I_1_1_1
I I I I I middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot middotmiddotmiddotmiddotmiddotmiddotmiddotfmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddot -r-t-o-rldegoo---shy
25 3 35 4 45 5 55
Density (lbsff)
Fig AS Conductivity vs Bulk Density
From the temperature data collected from the second thennocouple the thennal diffusivity
is computed (see Section A4) This thennocouple lies 3 mm (0118 in) from the heater
63
wire The output from the diffusivity iteration is provided in Table A2 A graphical
representation is given in Figure A6
Table A2 Average Fumed Silica Diffusivity for Various Bulk Densities
Test
Average Diffusivity m2s (ft2Jhr)
1 210 x 10-7 (000813)
2 166 x 10-7 (000643)
3 159 x 10-7 (000616)
4 155 x 10-7 (000600)
5 153 x 10-7 (000592)
6 No Data Available
7 151 x 10-7 (000585)
00085 -+----+-----f----+----+----+--_+_
I
middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1 ~0008
I I I I ~
I middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotfmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot Tmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot ~ 00075
~-shyf i ~ ~ ~ i ++middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotfmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot0007 i iii
~ rn ~ ~ i i~
(jj bullbullbullbullbullbull1bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullJLbullbullbullbullbullbullbullbullbullbullj ~ 00065o ~ middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot0006
I I I 00055 -+----+-----f----+----+----f--_+_
25 3 35 4 45 5 55
Density (lbsff)
Fig AS Diffusivity vs Bulk Density
64
A7 Conclusions
The primary conclusion from this experimental study is the fact that the thennal insulating
properties of fumed silica powder increase as the bulk density of the material increases
Although this study presents a limited range of density values the trends that were
expected are seen to be true The conductivity values are expected to reach and even
surpass those of CFC-blown foams that are used in household refrigerators Further
testing is needed to provide data that supports this expectation In addition testing in this
study was strictly limited to a single variety of silica This particular type of silica is not
necessarily the best candidate for thermal insulation applications Silica powders are by
nature hydroscopic This affinity for water has adverse effects on its thermal insulating
properties However silica powders are now produced with a special treatment which
transforms the material into a hydrophobic material Therefore if these new materials
maintain the thermal properties and density trends of the hydroscopic type they become
even more preferred insulators Once again data needs to be obtained to support this
notion Fumed silica offers a competitive alternative to the existing CFC-blown foams
without the obvious environmental drawbacks It is completely inert recyclable and
reusable It also competes well when comparing cost values CFC-blown foams are
between 003 - 007 $ft2_R-Value whereas fumed silica powder are between 005 -025
$ft2-R-Value The discrepancies are close enough to merit true consideration
AS Thermal Diffusivity Newton-Raphson Iteration Source Code
program difsivty implicit none double precision condqtime(lOO)temp(lOO)guessradiusalpha
+ dif(lOO)sumavedifgcurrentmasslengthpi + density integer nikrun OPEN (2file=Oiffusivityoutlposition=rewind) OPEN (3file=Oiffusivityinposition=rewind) OPEN (4file=Oiffusivityout2position=rewind)
print Enter input current in amps readcurrent printEnter calculated conductivity in Wm K readcond print Enter thermocouple distance in meters readradius print Enter mass of sample in grams readmass print Enter compacted length of sample in em readlength print Enter number of timetemperature data points
65
c
readn 5 print enter initial quess for beta
readquess c
pi=31415927 q=currentcurrent2214 density=(mass1000)laquopi4)(003844)(lenqth100raquo
c c check to see if converqence will occur c print Enter data point l c print (time and temp with a blank separatinq the two) c readtime(1)temp(1) c call diffus(condqtime(1)temp(1)quessradiusalphaq) c printinitial q=q c if (abs(q) qt 05) then c qoto5 c endif c
do 10 i=1n read(3) time(i)temp(i)
10 continue c
print print Input Current= current print write(2) Input Current= current write (2 )
c sum=OO do 20 k=1n call diffus(condqtime(k)temp(k)quessradiusalphaq) print Diffusivity for data pointk =alpha write(2) Diffusivity for data pointk =alpha write(4) alpha dif(k)=alpha sum=sum+dif(k)
20 continue c
avedif=sumn c
print print print INPUT print Conductivity=cond Wm K print Heater Input=q Wm print Thermocouple Distance=radius m print- print OUTPUT print Sample Density=density kqm3 print Averaqe Diffusivity=avedifmiddot m2s
c write(2) write(2) INPUT write(2) Conductivity=cond Wm K write(2) Heater Input=q Wm write(2) Thermocouple Distance=radius m write (2 ) write(2) OUTPUT write(2) Sample Density=density kqm3 write(2) Averaqe Diffusivity=avedif m2s
c c
pause stop
66
end
subroutine diffus(condqtimetempguessradiusalphag) implicit none double precision condqtimetempbeta(100)radius
+ f1f2f1pf2ptempf2tempf2pggppialphaCe + signfactol integer jkmn
c Ce=5772157 pi=31415927 beta (1) =guess tol=l j=l
c c begin Newton-Raphson iteration to find beta and ultimately alpha c
while (tol gt 0001) c print betaj =beta(j)
f1=-Ce20 - log(beta(j)) flp=-l Obeta (j) f2=00 f2p=00
c c start loop to compute the summations for f2 and f2 prime
do 10 k=2162 m=k2
c this loop gives the factorial for the kth term fac=10 do 5 n=lm
fac=facn 5 continue
sign=(-1)laquok+2)2) tempf2=laquobeta(j)k)sign)(kfac) tempf2p=laquobeta(j)(k-1))sign)fac f2=f2+tempf2 f2p=f2p+tempf2p
10 continue
c c compute the value of G and G which are both functions of beta c these will be used to update beta in the Newton-Raphson iteration c where beta(n+1)= beta(n)- GG
g=laquo20picondtemp)q)-(f1+f2) gp=- (flp+f2p)
c print g=g c here we check to see if the convergence criterion suggested c by Nix is met for the initial beta chosen if not we must jump out of loop c if (j eq 1) then c if (abs(g) qt 05) then c printconvergence not satisfied c printtry a s~aller guess for beta c return c endif c endif c c update the value of beta and compute a tolerance value c that will be used to check for convergence
beta(j+1)=beta(j)-(ggp) tol=abs(beta(j+1)-beta(j))
67
j=j+1 c protect against infinite looping
if (j eq 100) then goto 101
endif repeat
c c if the iteration converges then compute the value for diffusivity
alpha=(10(40timeraquo(radiusbeta(jraquo2
c c
101 return
68
APPENDIX B ONE-DIMENSIONAL SIMULATION SOURCE CODE AND OUTPUT
B1 Source Code
CPROGRAM FrigWall--Steady-State Heat Conduction with Convective and CRadiative Heat Transfer from interior and exterior surfaces C Programmed by AM CLAUSING
LOGICAL SI DIMENSION RA(2)XNU(2)R(2)H(2)HR(2)TF(2)TW(2)DT(2) COMMON AXLWXLC(2)HC(2)T(2)XKWBETANMAXSIE(2)SIGMA
CDetermine- direction of output read and print input data NCASE=l
1 CALL DATAIN(NCASEIUOUT) NCASE=NCASE+1 QOLD=O TW(1)=T(1)+1(T(2)-T(1raquo TW(2)=T(2)-1(T(2)-T(1raquo
CCalculate wall resistance RW=XLWXKWA DO 3 N=lNMAX DO S J=12
CCalculate the radiative equivalent heat transfer coefficients HR(J)=SIGMAE(J)(T(J)2+TW(J)2)(T(J)+TW(Jraquo
C Calculate the film temperatures TF(J)=(T(J)+TW(Jraquo2
CCalculate the convective heat transfer coefficients CALL GASPT(lTF(J)RHOXMUXKCPGRBPRIER) DT(J)=ABS(TW(J)-T(Jraquo RA(J)=PRGRBXLC(J)3DT(J) IF(RA(J) LT1E9) THEN
XNU(J)=0S2RA(J)2S ELSE
XNU(J)=09RA(J) 3333 ENDIF H(J)=XNU(J)XKXLC(J) IF(HC(J) NE O) H(J)=HC(J)
CCalculate surface resistances R(J)=l(H(J)+HR(JraquoA
S CONTINUE CCalc~late total resistance heat flow rate and surface temperatures
RT=R(1)+R(2)+RW Q=(T(2)-T(1raquoRT TW(l)=T(l)+QR(l) TW(2)=T(2)-QR(2)
CCheck for convergence If solution has converged exit loop ERRQ=ABS(Q-QOLD)100Q QOLD=Q IF(ERRQLT OS) GOTO 7
3 CONTINUE 7 WRITE (IUOUT 101) Q ERRQ (H (J) HR (J) RA (J) XNU (J) TW (J) DT (J) R (J) RT
2 J=l2) 101 FORMAT( Q =F61 W10XERRQ =FS2 T12 hconvT22hradT33
2 RaT44NuTS2 TsurT62 DeltaTT72RRtotT10 [Wm2-KjT20 2 [Wm2-KjTS3 [KjT63 [Kj InsideF72F92E133F91 2 F101F91F113 OutsideF62F92E133F91F101F91F113) DO 9 J=l2 IF(HC(J) NE bull O) WRITE (IUOUT 103) J
9 CONTINUE 103 FORMAT( NOTE hconv(I1 ) was specified not calculated)
GOTO 1 END
69
C SUBROUTINE DATAIN(NCASEIUOUT) LOGICAL SI COMMON AXLWXLC(2)HC(2)T(2)XKWBETANMAXSIE(2)SIGMA DATA AXLWXKWXLCHCTENMAXSIGMA2990360245315 2 20277297 959510567E-8
CDefinition of NAM NAMELIST NAMAXLWXKWXLCHCETNMAXBETASI CHARACTER FNAME60CDATE9CTIME8 PARAMETER (IUIN=7)
CIF First Case Open Files Write Program Description and Date IF (NCASEEQ 1) THEN
WRITE (6 100) 100 FORMAT( TYPE NAME OF INPUT DATA FILE)
READ( (A) ) FNAME COpen input and output files
OPEN (7FILE=FNAME) REWIND 7
C OPEN (10FILE=Plots-FNAME) C WRITE(6122) Plots-FNAME C122 FORMAT( COMMA DELIMITED PLOTTING FILE IS A)
WRITE(6118) 118 FORMAT (T10 DIRECT OUTPUT TOT20 SCREENT36 Type 6
2 T20 OUTPUT FILET36 Type 8T20 PRINTERT36 Type 9) READ() IUOUT IF(IUOUTEQ8) THEN OPEN (8FILE=Answers-FNAME) WRITE(6120) Answers-FNAME
120 FORMAT( OUTPUT WILL BE WRITTEN IN FILE A) ENDIF CALL DATE(CDATE) CALL TIME(CTIME)
CWrite Program Description and Date WRITE(IUOUT102)CDATECTIME
102 FORMAT( Program FrigWallT60 Date A10 Version 8 August 1991T60 2 Time A9 Programmed by AMClausing) ENDIF
CRead and Write Input Data READ(IUINNAMEND=999) WRITE (IUOUT 104) NCASETXLCEXLWXKWA
104 FORMAT ( CASE NUMBER 12 2 Ambient Temperatures IK] InsideF616X OutsideF61 2 Characteristic Lengths 1m] InsideF626X OutsideF62 2 Surface Emissivities8X InsideF626XOutsideF62 Wall
Thickness 2 F63 mT27 ConductivityF63 Wm-K2x AreaF52 m2) RETURN
999 WRITE (IUOUT 199) 199 FORMAT ( ALL INPUT DATA HAS BEEN PROCESSED) 991 CLOSE(10)
IF(IUOUTEQ 8) CLOSE(8) STOP END
C SUBROUTINE GASPT(NGASTRHOXMUXKCPGRBPRIER)
C PROGRAMMED BY A M CLAUSING VERSION APRIL 1982 C PROPERTIES OF GASES IN SI UNITS(TGTO) OR ENGLISH UNITS(TLT O) C FUNCTIONAL REPRESENTATIONS USED ARE OF THE FORM Y=ATB C ARRAYS A AND B CONTAIN THE RESPECTIVE CONSTANTS C INPUT C NGAS - NGAS=l IS AIR NGAS=2 IS NITROGEN C T ---- ABSOLUTE TEMP (K) OR NEGATIVE OF ABSOLUTE TEMP (R) C OUTPUT C RHO -- DENSITY (KGM3) OR (LBMFT3)
70
C XMU -- VISCOSITY (KGM-S) OR (LBMFT-S) C XK --- THERMAL CONDUCTIVITY (WM-K) OR (BTUHR-FT-R) C CP --- SPECIFIC HEAT (JKG-K) OR (BTULBM-R) C GRB -- GBETAXNU2 (1M3-K) OR (1FT3-R) C PR --- PRANDTL NUMBER (DIMENSIONLESS) C IER -- ERROR PARAMETER C INFORMATIVE ERRORS C IER=l --- GAS NUMBER DOES NOT EXIST GAS IS ASSUMED TO BE AIR C IER=2 --- TEMPERATURE OUT OF RANGE OF PROPERTY SUBROUTINE C RESTRICTIONS C NGAS -- MUST BE l(AIR) OR 2 (NITROGEN) C T ----- T MUST LIE BETWEEN 150K AND 2100K FOR AIR AND BETWEEN C 83K AND 450K FOR NITROGEN RANGES ARE SPECIFIED WITH ARRAY R C
DIMENSION A(152)B(152)R(32) DATA A36411764E-61423E-399084178E20123 235064914E-62494E-329944985E195930 3 432491E-81239E-415534379E201137 4351618E-6221E-31031408E2084130 DATA B-1005814913800316-4639-09685 2 -999642981521962-4284023930 3 -10469389466-079-5102-0872 4 -10058058 834500239-4636-0265230 DATA R150400210083160450 IER=O IFlaquoNGASGTO) AND(NGASLT3raquo GO TO 1 IER=l NGAS=l
1 1=1 TP=T IF(TLT bullbull O) TP=-T18 IFlaquoTPLTR(lNGASraquo OR (TPGTR(3NGASraquo) IER=2 IF(TPGTR(2NGASraquoI=7 RHO=A(INGAS)TPB(INGAS) XMU=A(I+1NGAS)TPB(I+1NGAS) XK=A(I+2NGAS)TPB(I+2NGAS) CP=A(I+3NGAS)TPB(I+3NGAS) GRB=A(I+4NGAS)TPB(I+4NGAS) PR=A(I+5NGAS)TPB(I+5NGAS) IF(TGT O)RETURN RHO=RHO1602 XMU=XMUl 488 XK=XKl 731 CP=CP4187 GRB=GRB6357 RETURN END
B2 Output
Program FrigWal1 Version 8 August 1991 Programmed by AMClausing
Date Time
05-MAR-92 200227
CASE NUMBER 1 - Fresh Food Walls
Ambient Temperatures IK] Inside 2770 Outside 2940 Characteristic Lengths 1m] Inside 030 Outside 150 Surface Emissivities Inside 095 Outside 095
71
Wall Thickness 0045 m Conductivity 0027 Wm-K Area 242 m2
Q = 209 W ERRQ = 002
hconv [Wm2-K]
Inside 1 98 Outside 130
hrad [Wm2-K] 461 544
Ra
0488E+07 0459E+09
Nu
244 761
Tsur [K]
2783 2927
DeltaT [K] 13 13
RRtot
0077 0075
CASE NUMBER 2 - Fresh Food Door
Ambient Temperatures [K] Inside 2770 Outside 2940 Characteristic Lengths [m] Inside 030 Outside 150 Surface Emissivities Inside 095 Outside 095 Wall Thickness 0040 m Conductivity 0040 Wm-K Area 089 m2
Q = 117 W ERRQ = 001
hconv [Wm2-K]
Inside 218 Outside 144
hrad [Wm2-K] 463 542
Ra
0714E+07 0690E+09
Nu
269 843
Tsur [K]
2789 2921
DeltaT [K]
19 19
RRtot
0114 0113
CASE NUMBER 3 - Freezer Walls
Ambient Temperatures [K] Inside Characteristic Lengths [m] Inside Surface Emissivities Inside
2630 030 095
Wall Thickness 0056 m Conductivity 0027
Outside Outside Outside
2940 150 095
Wm-K Area 110 m2
Q = 14 3 W ERRQ = 003
hconv [Wm2-K]
Inside 226 Outside 143
hrad [Wm2-K] 397 542
Ra
0990E+07 0684E+09
Nu
292 841
Tsur [K]
2651 2921
DeltaT [K]
21 19
RRtot
0067 0061
CASE NUMBER 4 - Freezer Door
Ambient Temperatures [K] Inside 2630 Outside 2940 Characteristic Lengths [m] Inside 030 Outside 150 Surface Emissivities Inside 095 Outside 095 Wall Thickness 0040 m Conductivity 0040 Wm-K Area 034 m2
Q = 81 W ERRQ 002
hconv [Wm2-K]
Inside 259 Outside 1 64
hrad [Wm2-K] 400 538
Ra
0169E+08 0124E+10
Nu
333 967
Tsur [K]
2666 2906
DeltaT [K] 36 34
RRtot
0117 0110
72
__ ___
APPENDIX C TEST REFRIGERATOR DESCRIPTION
The test refrigerator is a White-Westinghouse model RT193MCWO 186 cubic foot
capacity top-mounted unit It is equipped with full automatic defrost The cycle time for
this unit is approximately 50 The unit also has two anti-sweat devices An electric
heater is located in the mullion region to prevent frosting between the freezer and the fresh
food compartments Also a condenser tube runs around the entire outside perimeter of the
unit embedded beneath the steel all flange Figure C1 illustrates these features
~1-- 0787 m (31)__
~ r_----------------------
1581 m
Fig CI Location of Anti-sweat Devices and Overall Dimensions of Test Refrigerator
73
Under test conditions the refrigerator and freezer are filled with milk containers full of
water These containers provide sufficient thennal mass to minimize temperature
fluctuations dming experimental runs Twenty gallons are present in the fresh food
compartment and 6 gallons are in the freezer
Figures C2 through C5 give the detailed dimensions of the fresh food compartment and
the freezer All dimensions are in millimeters and are obtained directly from the unit
Dimensions are estimated to be accurate to within plusmn 3 mm
697
762
1
305
717
Fig C2 Fresh Food Compartment Interior Dimensions
74
1127
Fig C3 Fresh Food Door
75
675
381
Fig C4 Freezer Interior Dimensions
432
Fig CS Freezer Door
76
APPENDIX D DATA ACQUISITION AND CONTROL SYSTEM
Corresponding with the construction of the experimental apparatus was the purchase and
assembly of a data acquisition and control system The system itself was designed to meet
the needs of a variety of experiments and is therefore a very flexible system
The system consists of six DC power supplies a data acquisition chassis a computer a
rack ofdigital relays and a variety of analog and digital inputs and outputs A data
acquisition and control software package orchestrates the interactions between these
components and regulates outgoing signals as well as providing data storage
External signals enter the system through a Keithley 500P data acquisition chassis These
signals consist of voltage and current measurements from the power supplies as well as
thermocouple voltages At present a total of ninety-six thermocouple inputs are available
with an optimal resolution of +0012 degrees C The addition of more thermocouple input
boards could expand the capability to 128 inputs Also special boards can be installed to
allow strain gauge thermistor digital or other standard data acquisition functions The
Keithley chassis can contain a total of nine interface boards and its l~bit AID conversion
allows for very high resolution
The six DC power supplies consist of two Hewlett Packard and four Sorensens with a
combined power of 7560 watts The Sorensens are rated at 0-150 volts at a maximum of
12 amps while the Hewlett Packards produce 0-60 volts at a maximum of 3 amps All of
the power supplies are computer-controlled however the Sorensens may be operated
manually ifdesired Voltage measurements from the power supplies are fed into the
Keithley acquisition chassis and are then routed to the computer A voltage from the
computer is buffered and fed into the control circuits of the power supplies This voltage
completes the loop and controls the output voltage of the power supplies The software is
responsible for reading the output voltage of the power supplies comparing it with the
intended setpoint and adjusting the control voltage as needed This arrangement allows the
user to vary the output voltage of the power supplies from within a program Computershy
controlled safety relays are in place to disconnect the power supplies should they stray too
far from the intended voltage setpoint Fig D1 displays the system
77
Thermocouple and Voltage Inputs
r
Computer Data Acquisition Chasis Intaface
00 Voltage and 1 r Current
Measurement
Computer
I I
Analog Control Signal
Digital Oulput Signals 5 6
Power Supply 4 Relay Rack
Power Supply 3 00000001 Power Supply 2
Buffered Analog100000001 Power Supply 1 Control Signal
1 2 3 4 5 6 - I
I00 00 )0 po po po
Ir Digital Outputs
Analog Outputs
Fig DI Data Acquisition and Control System
78
APPENDIX E EXPERIMENTAL RAW DATA AND PLOTS
E1 Temperature Profile Plots From Fixed Thermocouples
In this appendix the remaining tests for the fixed thennocouple testing presented in Section
41 are provided Figures E1 and E2 give the results from the fresh food compartment
and Figures E3 and E4 give the results from the freezer Notice the outdoor and interior
ambient temperatures are not the same as the two tests presented in Section 41
191
Run 2 ttl ~ i i
middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot
middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot-imiddotmiddot
TWall
middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotlmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot
-
Outdoor Ambient =210 degC Fresh Food Ambient =375 degC
-] _ Door ProfUe i -il- 0 Wall Profile
i 19
$-- - Tdo = 19078 - 001326x
l~l ~~i 189 i i a m
0 i -m-
i 188 middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot
187 ~ middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot 5 = 18989 - O02024x 1
F 186
~bullbullbullbullbullbullbullmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot185 i i
184 0 5 10 15 20 25
x (mm)
Fig E1 Steel Skin Temperature Plot for Fresh Food Compartment (Run 2)
79
191
19
189
a ~
i 188
187
5F
186
185
184 0
Run 3 I --D - Door Profile
middotmiddotmiddotmiddotmiddotmiddotmiddotmiddot-middotmiddotmiddotmiddot~middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotimiddotmiddot-middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddot 0 Wall Profile
i - i - - Tdo =19053 - 001384x or
=c-=r=-~-= 1 11=
~ n - 189S 001998 --t-shy-~~-
5 10 15 20 25
x (mm)
Fig E2 Steel Skin Temperature Plot for Fresh Food Compartment
186
184
182
- ~- 18
178
~ 176
174
172 0
(Run 3)
Run 2 l --0 - Door Profile
middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot~middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotdrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotf 0 Wall Profile - 1- - middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot--m
- - T =18544 - 002398x i - i door rb
~i
i bullbullbulli _ bull imiddot
~ I TWall =18182 - 003542x tmiddotmiddotmiddotmiddot middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotlmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot
~ n~l l
5 10 15 20 25
x (mm)
Fig E3 Steel Skin Temperature Plot for Freezer (Run 2)
80
--a 0
I5F
186
184
182
18
178
176
174
172
Run 3 I --0 - Door Profile
middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotCmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotl 0 ~a1l Profile
ttl __ OJ 1 1 middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotfmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotlmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot -shy - Td = 18411 - 002272x ibullbullbullbullbullbullbull-bullbullbullbullbullbullbullbullbulli
oor ~
rp bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbull bull 11_1
I I middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotimiddotmiddotmiddotmiddot middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotImiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot
~ _l
Outdoor Ambient =208 degc Freezer Ambient = -93 degc
0 5 10 15 20 25
x (mm)
Fig E4 Steel Skin Temperature Plot for Freezer (Run 3)
E2 Thermopile Data Reduction
The data from the thennopile tests consist of an output voltage (mV) measured with a
Keithley multimeter which has a resolution of 1 m V The procedure required to translate
this voltage into a temperature difference follows
1 Read the output voltage in millivolts
2 Detennine the average skin temperature from fixed thennocouple data
3 Use the reference table and the average skin temperature to determine the conversion factor in Vrc
4 Convert to temperature difference as follows
1T = ____o_utpu_t_vo_l_tag-e___
ofjunctions x conversion factor
81
Table EI Thermopile Raw Data
ffOutput fzOutput ff Ave Skin Temp fz Ave Skin Temp mV mV CC CC
Roo wall door wall door wall door wall door
1 0052 0048 0045 0050 189 191 177 183
2 0054 0052 0046 0048 187 189 176 182
3 0056 0053 0046 0051 186 188 175 181 ff Conv Factor fz Conv Factor ff AT fzAT
Ilvrc Ilvre CC CC
Roo wall door wall door wall door wall door
1 40165 40181 40067 40116 026 024 037 041
2 40148 40165 40058 40107 027 026 038 040
3 40140 40157 40050 40099 027 026 038 040
Average Temperature Difference 0267 0377 0253 0403
from Thermocouple Reference Tables Based on the IPTS-68 US Dept of Commerce
E3 Experimental Determination of qwall and qdoor Details
The four heat fluxes are calculated using
-k M (El)q - m Ax
For 05 carbon cold rolled steel km =540 Wm K (312 Btuhr-ft-OF) Also Ax = OOlm (039 in) for all computations
0267degC 2 qwallff = 54 Wm-K 001 m = 14418 Wm
_ 0377 degc _ 2 qwallfz - 54 Wm-K 001 m - 20358 Wm
0~3~ 2 qdoorff =54 Wm-K 001 m =13662 Wm
82
0403degC 2 qdoorfz = 54 Wm-K 001 m = 21762 Wm
Compute the heat transfer rate according to Equation (B2)
q =qA=qhP (B2)
Where A is the cross sectional area of the steel casing that is perpendicular to the direction
of heat flow The area is the product of the steel skin thickness b and the total perimeter of
the compartment opening which is exposed to the room environment P Perimeter
definitions
Pwallff = llm + 076m +llm = 296 m
roJ D Pwallfz =O4lm + 076m + O4lm =l58 m
I ] I ~I Pdoorf( = llm + 076m + llm + 076m = 372 m
Pdoorfz =076m + O4lm + 076m + 041m =234 m
83
qwallff =(14418 Wm2)(65e-4 m)(296 m) =277 W
qwallfz =(20358 Wm2)(65e-4 m)(158 m) =209 W
qdoorff =(13662 Wm2)(65e-4 m)(372 m) =330 W
qdoorfz =(21762 Wm2)(65e-4 m)(234 m) =331 W
E4 Temperature Profile Plots From Mullion Data (Heater oro
The following plots are from the remaining runs for the mullion analysis presented in
Section 45 All data is taken from the exact center of the mullion
131
13 middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot-tmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotjmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotlmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot9middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotlmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot6middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddot T 11 f =12383 + 0019929x iii mu z
129 ~ middotImiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot[middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddota ~
i 128 middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot4middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot-j-middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotfmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotfmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot
127e ~
126 ~~~=H~~-~=HmiddotrI~ ++~11 Room Ambient =2250 degC125
1 1 i Fresh Ambient =515 degC iii i i Freezer Ambient =-603 degC
124
1 10
Fig ES Mullion Temperature Profile Run 2 (Heater Off)
Run 2
2 3 4 5 6 7 8 9
TIC
84
146
145
a 144 ~
i 143
5 ~ 142
141
Run 3 9 0
---r-r--deg-r-ideg-t-9--rshyiii ltD T 11 ff = 15173 - OOI71x mu bull
middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotfmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotImiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot6middotmiddot
1Tmull~fz =14062 + J0158211x JLt 1
Q 1 1 1 middotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1-middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddoti-middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotimiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotoot-middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot-I-bullbullbull~bullbullbullbullbullbullbullbullbullbullbull
iii middotiiimiddot-j Room
1Am~t = 21~1 degC
iii i 1 Fresh Ambient = 563 degC 1 1 1 1 1 Freezer Ambient = -153 degC
14~---+--~----r---+---~---+--~----r---+-
1 2 3 4 5 6 7 8 9
TIC I
Fig E6 Mullion Temperature Profile Run 3 (Heater Off)
127
126
125 a ~
i 124
123 e ~
122
121
12
1
Fig E7
i i CD middotmiddotmiddotmiddot----middotmiddot-r--middot---middotmiddotmiddotmiddotmiddotmiddot-lmiddot--------middotmiddotmiddotmiddotl-middotmiddot---middotmiddotmiddotmiddot---r---middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1middotmiddotmiddotmiddotmiddot---middotmiddot---middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot-r----middot1__ _-
I I I T mulIff = 1321 - 001532x middotmiddotmiddotmiddot------middott--------------tmiddotmiddot----middot----middotmiddot-1------middotmiddotmiddotmiddotmiddotmiddot---jmiddot-----middotmiddotmiddotmiddotmiddotmiddotmiddotmiddot-lmiddotmiddotmiddot---middotmiddotmiddot-----tmiddotmiddotmiddotmiddotmiddot--middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddot-----middotmiddotmiddot6middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot
I cent I I I I -~~~~-ro-Tr-
r-middotmiddotmiddotmiddotrTTr-middotrmiddotrmiddotrmiddot middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddott middotmiddotmiddottmiddotmiddot1middotmiddotbullbullbullbull fmiddotbullbullbullbullbullbullbullmiddot-fbullbullbullbullbullbullbullmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot
II Room Ambil =21~3 degC iii i i Fresh Ambient =551 degc iii i i Freezer Ambient = -681 degC
2 3 4 5 6 7 8 9 10
TIC I
Mullion Temperature Profile Run 4 (Heater Off)
85
10
111
iii i i 11
Fttul5
T mu
=J=~[rr~tl=rI=109
a ~ 108 -t-t-t-i~FFl~i~~
+-0amp_- -+_bullbullbullbullbullbullbullbull+ - bullbullbull 107 11 f ~ 10325 + 0021893x 1 1 1 ji
5 bull Z iii
------~-~-----~---i --L--l ---_l__ ---L-----_shy106 ~
105 -t---i--+-+-+-middot++-I-shyL1LLL Room Ambient = 2177 C104 iii i i Fresh Ambient =448 degC
Freezer Ambient = -644 degC 103
1 2 3 4 5 6 7 8 9 10
TIC
Fig E8 Mullion Temperature Profile Run 5 (Heater Off)
86
34
33 1 1 1 1 1 1 1 1------I---------middotmiddot--+middotmiddotmiddotmiddot------middottmiddot-------middotmiddotmiddotmiddottmiddot----------middotmiddotmiddot---middot---middot----tmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot---middotmiddott--middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot(middotmiddotmiddotmiddotmiddot--
32 11 f =1 2859 ~ OI~X j
Till ff =133013 j - 007124x mu
31
a ~ 30
i 5 ~
29
28
27
26
Tmullfz = 26944 + 014842x
mu t-tr l
25 middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotjmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotjmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotlmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1middot ~ u~ ~it
24 lllti1 ~ i i ~ i
0 Lower Limit
23
0 1 2 3 4 5 6 7 8 9 10
ES Temperature Profile Plots From Mullion Data (Heater On)
The following are the remaining plots from the mullion heater analysis presented in Section
46
TIC I
Fig E9 Mullion Temperature Profile Run 2 (CenterHeater On)
Run 2
T muz
1
87
l----+
29
middotmiddotmiddotgtmiddotmiddoti middot 0 upper Limit 28 Run 1
I
middotmiddotI o
Tmullfz
T muo
LL~4cb 0 Lower Limit27
middot~+ImiddotmiddotmiddotImiddotmiddotmiddottr9middotdJmiddotmiddotmiddotmiddot 26
t T = 29465 008022xmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddot1middotmiddotmiddotmiddotTmiddotmiddotmiddotmiddot[middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1middot mullffa 25~
i 24 =24837+ 013186x middotlmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot+middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotimiddotmiddotmiddotmiddotmiddotmiddotmiddotlmiddotmiddotmiddotmiddotmiddotmiddot iii i i
i _ Jbullbullbullbullbullbullbullbullbullbullbullbullbulli l _l ii 23
e 22~ 21 +I~=tt=l=fit
L~LLL Tm~llff = 23856 005858x20 11 f = 1803 + 02243x z -rmiddotmiddotmiddotmiddot1middot middotmiddot middotmiddot 1middotmiddotmiddotmiddotmiddotTmiddotmiddot middot-rmiddot19
18
0 1 2 3 4 5 6 7 8 9 10
TIC
35
34
33
32
a ~ 31
I ~
30
29
28
27
26
25
24
Fig EI0
---bull---i----bullbullmiddotmiddotmiddotmiddot--~--------middotmiddot-+------ j bullbullbullbull ---bullbullbullbull -i--__---
T 11 f =30063 + OI~x 1 T i 134 196 i
0068 1 38
muz tmiddotmiddot Ilff=middot bull x ltP lt1gt mu
=t=H=t+t=R=t= F-6~I-i~E
Tmullfz = 28103 + 014486x 1middot++middot1middot1
middotmiddotmiddot--middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotimiddotmiddotmiddotmiddotmiddotmiddotmiddot-middotmiddotmiddotmiddotmiddot+middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotbullbullmiddotmiddotmiddot-middotmiddotimiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot~middotmiddot
111111 0 Upper Limit iii iii 0 Lower Limit
0 1 2 3 4 5 6 7 8 9 10
TIC
Mullion Temperature Profile Run 3 (CenterHeater On)
Fig Ell Mullion Temperature Profile Run 1 (LeftHeater On)
88
a
29
28
27
26
25~
i 24
23 e
22~ 21
20
19
18
Fig E12
i l middot middotmiddotmiddotmiddotlmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot+ 0 Upper Limit T 11 f =24474 + 011288x i imu bull z o Lower Limit
=tplusmntplusmnfrplusmnplusmnplusmn ~ I I I I Tmull ff ~ 28793 - o0784x
middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddott----middot------middotmiddotimiddot----middot-middotmiddot--middot-~-middotmiddotmiddot--middot----middotmiddot)middot
=ii=t=1=P-Ltplusmnt iii i T = 25599 - 00689xIfmiddotTTTmiddotmiddotrmiddot ~Ullff iii
T l1f =20552 + 01676x i~~imiddotimiddotmiddot
==~LL L LLLLL i i 1 ~ 1 ~
0 1 2 3 4 5 6 7 8 9 10
TIC I
Mullion Temperature Profile Run 2 (LeftlHeater On)
33 iii i i
-middot--middot(---middotmiddot--middotmiddot--middotmiddot+---middot-middotmiddotmiddotmiddot-middotmiddotmiddot~-middot--middot-------middoti---middot------~ o Upper Limit 32 Run 3
t bullbullbull +
Tm~llfz
T mu
1 1 1 1 1 o Lower Limit ~~31
=2713 ~ 0113~x j11Li30
a T ulff =30658 - 006506x 29~
IktlJ2~Li 28
27 e
26 =l=tt=tmiddotmiddottmiddott+~middot+=t=~ middotmiddot jmiddotjmiddottmiddottmiddotjmiddot T = 28288 - 00603x
iii i mullff 24
25
middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotQmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot+middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot~middotmiddotmiddot middotmiddotmiddotmiddotmiddotmiddotmiddotmiddot~middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot+middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot 11 fz = 2377 ~ 01788x IL11123 i i
22
0 1 2 3 4 5 6 7 8 9 10
TIC I
Fig E13 Mullion Temperature Profile Run 3 (LeftHeater On)
89
31
30
29
ltP ~u
J
1 T
-~Lti=t~-t--t i~+--Ij Tmu1lff =31473 middot005222x 28
1 1 1middot 1 l i l i bullbullbullbullbullbullbull__ bullbullbullbull_ bullbullbullbullbullbullbull~_bullbullbullbullbullbullbullbullbulla bullbullbullbullbullbullbullbullbullbullbull a 27
~ Tm~llfz = 26857 + 01734x _~__+_+II i
26
bullmiddotmiddotbullbullbullmiddotmiddotbullibullbullbullbullbullbullbullbullbullbullbullmiddotmiddotmiddotbullbullbullbullbullbullbullbullmiddotmiddotmiddotmiddot bullbullbullbullbullbullbullbullbull-i-~-i-ii25
JJ$~L-f$9 5 24
~ 23 middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotlmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot+middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot~middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot+middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1-middotmiddot T mllff =25622 bull 002~7X c-bullbullbullbullbullbullbullbullbullbullbullbull+ ~~ 22 rp 1 1 i i 1 1 1
21 = 19464 + 02548 jmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddott Upper Limitmullfz xii 0
4-bullbullbullbullbullbullbullbullbullbullbullbullimiddotmiddotmiddotbullbullbullbullbullbullmiddotf20 i 1 ~ 1
19
0 1 2 3 4 5 6 7 8 9 10
TIC I
Fig E14 Mullion Temperature Profile Run I (RightHeater On)
33 i
middotmiddotmiddotmiddotlaquomiddotmiddotmiddotmiddot------------------------------- c--------middotmiddotmiddot-middot-----------middotmiddotmiddot---middotmiddot--------l-----middot-----I-----32
= 2757 + 017006x ILLJ1
a
31
30
29~
i 28
Run2
TmulIfz
T~ulIfz ~
-~t=ii~Ii~~~~ i
27 middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot9-middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotT~~middotmiddotmiddotmiddotmiddot2s944-middot~middotmiddotO0278~middotmiddote 26~ r~rrTt+rr25
24 2320~ + O~S4x middotmiddotlmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotjmiddot ~ u~ L~t 23 middotmiddotmiddotmiddotmiddotmiddotmiddotmiddot~middotmiddotmiddotmiddotmiddotmiddotmiddot+middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot+middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot+middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotImiddotmiddotj 0 Lower Limit
22
0 1 2 3 4 5 6 7 8 9 10
TIC I
Fig EIS Mullion Temperature Profile Run 2 (RightlHeater On)
90
33 i i ~ _______ _ _~____ __ __-i--bullbullbullbullbullbullbullbull-t------ -- uu__~ ~ --~32
=1268931+ 0~4~14X 111131
30
a 29~
I 28
Run3
Tmullfz
i t+ I T
m
mnplusmn~~27 6 i 1 i 1 +++ T mullff =28912 - 002938x 26~ +middotmiddot++Imiddotjmiddott-25
= 22996 + 02312x 1middotmiddot+ 24
~~~~L lL1 0 ~23 ill 0 22
0 1 2 3 4 5 6 7 8 9 10
TIC
Fig E16 Mullion Temperature Profile Run 3 (RightHeater On)
91
APPENDIX F NUMERICAL SIMULATION EQUATIONS AND CODE
F1 Finite-Difference Equations
Figure Fl is a generic resistor network that is used as a base for all the finite-difference
equations The general fonn is
(Fl)
r----II ij+l
J
i j-l L ______--J
Fig F1 Generic Nodal Resistor Network
This makes it easy to simply plug in the different resistors for the different regions of the
section There are twelve resistors total The following table summarizes the resistors
needed to complete the model
Table F1 Model Resistors
Description Resistance [CIW]
Interior insulation x direction Rl= dx dymiddotkinsmiddotb
92
dyInterior insulation y direction R2= dx-kins-b
dySteel parallel with insulation y direction R3= km-dm-b + kins-(dx -dm)
dxR=Steel parallel with insulation x direction km-dm-b + kins-(dy -dm)
dyRs=Plastic parallel with insulation y direction
kp-dp-b + kins-(dx -dp)
dxPlastic parallel with insulation x direction R6= kp-dp-b + kins-(dy -dp)
heffa- (~- dm) + kinsSteel to exterior x direction R7= 2
heffo-kins-dy-b
heffa- (dY - dm) + kinsSteel to exterior y direction R - 28shyheffo-kins-dx-b
hefti- (dY _dm) + kinsSteel to interior y direction R9= 2
heffi-kins-dx-b
hefti- (~- dp) + kinsPlastic to interior x direction RIO= 2
heffi-kins-dy-b
Rll = hefti- (dJ -dP) + kinsPlastic to interior y direction
heffi-kins-dx-b
93
Steel skinplastic skin interface
2middotkmmiddotdmmiddotkpmiddotdpmiddotdxR12=----------------------~~----------------
2middotkmmiddotdmmiddotkpmiddotdpmiddotbmiddot(dy -dp) + (kpmiddotdp + kmmiddotdm)middotbmiddotdx2
F2 Wall Simulation Source Code
Program FiniteDiff
c This program simulates the conductive heat transfer through the wall section c of the refrigerator near the door gasket using Guass-Siedel iteration c The program allows for flexibility in the geometry and material properties c The program is a steady-state model
cVariable Definitions
c km = conductivity of the outer metal skin (Wm-K) c kins = conductivity of the polyurethane foam insulation (Wm-K) c kp conductivity of the inner plastic skin (Wm-K) c dm = thickness of the metal skin (mm) c dp = thickness of the plastic skin (mm) c b = depth of the section (m) c heffo = effective heat transfer coefficient on outside surfaces (Wm2-K) c heffi = effective heat transfer coefficient on inside surfaces (Wm2-K) c sl width of wall inSUlation (mm) c s2 length of wall section (mm) c s3 seal indentation (mm) c s4 seal width (mm) c s5 distance metal skin travels into cabinet (mm) c s6 distance platic skin travels out of cabinet (mm) c ns = number of nodes corresponding to the s regions above c rs = network resistors (m-eW) c i = integer values of distance along the x axis c j = integer values of distance along the y axis c imax maximum integer value in x direction c jmax maximum integer value in y direction c iter total number of iterations to converge c loop convergence flag c Qinl Heat flux per unit length across the outer boundary (Wm) c Qin2 Heat flux per unit length across the inner boundary (Wm) c Qdif Qinl - Qin2 (Wm) c Qpdif = percent difference between the heat fluxes Qinl and Qin2 c Ti Inside ambient temperature (e) c To = Outside ambient temperature (e)
cDeclare Variables
INTEGER nln2n3n4n5n6ijloopimaxjmaxiter INTEGER clflaglflag2 REAL kmkinskpdmdpdxdyheffoheffi REAL TiToQdifQpdifQinlQin2 REAL sls2s3s4s5s6lenoutlenin REAL rlr2r3r4r5r6r7r8r9rlOrllr12 REAL T(-1lOl-1lOl)bqlDsumlsum2 REAL Qm(lOl)qfluxm(lOl)fluxo(OlOl)fluxi(OlOl)
94
REAL fluxcen(0101)pfluxcen(0101)pfluxo(0101) REAL pfluxi(0101)pmaxdifoneDtolaq2Dqedge1
OPEN (10file-2Dcode(v11)out1position-rewind) OPEN (11file-2Dcode(v11)out2position=rewind)
cTest Parameters
c thermal conductivity of the outer metal skin (Wm K) km-540
c thermal conductivity of the wall insulation (Wm K) kins=0021
c thermal conductivity of the inner plastic skin (Wm K) kp=015
c thickness of the metal skin (mm) dm=065
c thickness of the plastic skin (mm) dp=25
c effective heat transfer coefficient on outside surfaces (Wm2-K) heffo=681
c effective heat transfer coefficient on inside surfaces (Wm2-K) heffi=610
c width of section (mm) sl=450
c length of section (mm) s2=2000
c depth of the section (m) b=10
c inside ambient temperature (C) Ti=95
c outside ambient temperature (C) To=210
c unit conversions dm=dm1000 dp=dp1000 sl=sl1000 s2=s21000
c specify 1-dimensional tolerance (t) oneDtol=30
cMesh Parameters
c specify the following nodal mesh parameters n1=20 n2=80 n3=1 n4=9 n5=10
c various mesh dimensions dx=sln1 dy=s2n2 s3=n3dx s4=n4dx s5=n5dx s6=sl-s5-dx n6=s6dx imax=n1-1 jmax=n2-1
cInitialize temperature matrix
DO 10 j=-1jmax+1 DO 20 i=-1imax+1 T(ij)=Ti
95
20 CONTINUE 10 CONTINUE
DO 30 j=Ojmax T(-Ij)=To
30 CONTINUE
DO 40 i=0n3 T(i-I)=To
40 CONTINUE
DO 50 j=Ojmax T(imax+lj)=Ti
50 CONTINUE
DO 60 i=n3+n4+1imax T(i-I)=Ti
60 CONTINUE
cResistors [m-CW]
c interior insulation x direction rl=dx(kinsdy)
c interior insulation y direction r2=dy(kinsdx)
c metalinsulation y direction r3=dy(kmdm+kins(dx-dm))
c metalinsulation x direction r4=dx(kmdm+kins(dy-dm))
c plasticinsulation y direction r5=dy(kpdp+kins(dx-dp))
c plasticinsulation x direction r6s dx(kpdp+kins(dy-dp))
c metal to exterior x direction r7=(heffolaquodx2)-dm)+kins)(heffokinsdy)
c metal to exterior y direction rB=(heffo laquody2)-dm) +kins)(heffokinsdx)
c metal to interior y direction r9=(heffilaquody2)-dm)+kins)(heffikinsdx)
c plastic to interior x direction rl0=(heffilaquodx2)-dp)+kins)(heffikinsdy)
c plastic to interior y direction rll=(heffilaquody2)-dp)+kins)(heffikinsdx)
c metalplastic interface rI2=(2kmdmkpdpdx)(2kmdmkpdp(dy-dp) + (kpdp+km dm)dxdx)
cxxxxxGuass-Siedel Iterationxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx loop=1 iter=1 DO WHILE (loop eq 1)
c Equations for row 0 i=O j=O CALL sseqn(Tr4r7r3rBijimaxjmax)
DO 70 i=ln3 j=O CALL sseqn(Tr4r4r2rBijimaxjmax)
70 CONTINUE
DO 75 i=n3+1n5-1
96
j=O IF (i le n3+n4) THEN
CALL sseqn(Tr4r4r21e20ijimaxjmax) ELSE
CALL sseqn(Tr4r4r2r9ijimaxjmax) ENDIF
75 CONTINUE
i=n5 j-O IF (i le n3+n4) THEN
CALL sseqn(Tr12r4r21e20ijimaxjmax) ELSE
CALL sseqn(Tr12r4r2r9ijimaxjmax) ENDIF
i=n5+1 j=O IF (i le n3+n4) THEN
CALL sseqn(Tr6r12r21e20ijimaxjmax) ELSE
CALL sseqn(Tr6r12r2rllijimaxjmax) ENDIF
DO 80 i=n5+2imax-l j=O IF (i le n3+n4) then
CALL sseqn(Tr6r6r21Oe20ijimaxjmax) ELSE
CALL sseqn(Tr6r6r2rllijimaxjmax) ENDIF
80 CONTINUE
i=imax j=O CALL sseqn(TrlOr6r5rllijimaxjmax)
c Equations for rows 1 thru jmax-l DO 90 j=ljmax-l
i=O CALL sseqn(Tr1r7r3r3ijimaxjmax)
DO 100 i=1imax-1 CALL sseqn(Tr1r1r2r2ijimaxjmax)
100 CONTINUE
i=imax CALL sseqn(Tr10r1r5r5ijimaxjmax)
90 CONTINUE
c Equations for row jmax j=jmax i=O CALL sseqn(Tr1r710e20r3ijimaxjmax)
DO 110 i=1imax-1 j=jmax CALL sseqn(Tr1r110e20r2ijimaxjmax)
110 CONTINUE
i=imax j=jmax CALL sseqn(Tr10r11Oe20r2ijimaxjmax)
97
c c c
Compute the difference in heat flux crossing the outer boundary and crossing the inner boundaryr ideally the difference should be zero
CALL balance(TToTidxdyn3n4imaxjmaxQdifQpdif c QinlQin2r7r9r8rlOrllb)
c Update loop variables iter-iter+l
c Convergence criterium IF (Qpdif le 20) then
loop-O ENDIF IF (iter eq 10000) THEN loop=O write(lO) Solution did not converge
ENDIF
END DO cxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
cHeat Transfer Calculations
c Compute 10 heat flux through wall CALL oneD (ToTiheffoheffikmkinskpdmdpslqlD)
c Compute the flux thru wall at each node on the c outside and inside walls [Wm2) Also the flux c in the x-direction across the center line of the c section
cl-int(nl2) fluxcen(0)=(1(r4dy))(T(cl0)-T(cl+l0)) fluxo(0)=(1(r7dy))(To-T(00)) fluxi(O)=(l(rlOdy))(T(imaxO)-Ti) DO 112 j=ljmax
fluxcen(j)=(l(rldy))(T(clj)-T(cl+lj)) fluxo(j)=(1(r7dy))(To-T(0j)) flumiddotxi (j) =(1 (rlOdy)) (T (imax j)-Ti)
112 CONTINUE
c Determine the percent of steady-state 10 losses DO 113 j=Ojmax
pfluxcen(j)=(fluxcen(j)qlD) 100 pfluxo(j)=(fluxo(j)qlD)lOO pfluxi(j)=(fluxi(j)qlD)lOO
113 CONTINUE
c Determine where the heat transfer becomes 10 c based on a criticle percentage
flagl=O DO 114 j=O jmax
a=abs(pfluxcen(j)-lOOO) IF (j ne jmax) THEN
IF (a le oneDtol) THEN jstar=j
ENDIF ELSE
IF (a le oneDtol) THEN jstar=j
ELSE flagl=l
ENDIF ENDIF
98
114 CONTINUE
c Determine the edge loss by subtracting the 10 heat c transfer from the heat transfer in the 20 region c across the centerline
flag2=0 IF (flagl eq 0) THEN
q2D=00 DO 115 j=O jstar
q2D-q2D+fluxcen(j) 115 CONTINUE
qedgel=q2D-qlD ELSE
flag2=1 ENDIF
c 10 heat flux along metal skin under the seal into c the cabinet [Wm2J Fluxes for all metal nodes are c computed as well as an average flux The flux from c node (n3+l0) to node (n3+20) is given as qlDm(l) c and so on Assume the temperature of the metal skin c is the temperature of the node at that location
suml=OO sum2=00 DO 119 i=n3+1n3+n4-l
Qm(i)=laquokmdmb)dx)(T(i0)-T(i+10raquo qfluxm(i)=(kmdx)(T(iO)-T(i+lOraquo suml=suml+Qm(i) sum2=sum2+qfluxm(i)
119 CONTINUE pmaxdif=laquoQm(n3+n4-l)-Qm(n3+1raquoQm(n3+lraquo100 qedge2-qfluxm(cl)
cOutput
c Output nodal temperatures to separate file DO 120 j=Ojmax
write(ll) (T(ij)i=Oimax) 120 CONTINUE
c Output flux info to a different file write(10) INPUT PARAMETERS write(lO) write (10 ) Section Dimensions (mm) write(lO) Width sl1000 write (10 ) Length s21000 write(10) Depth blOOO write(10) Steel skin thickness dmlOOO write(lO) Plastic skin thickness dplOOO write(lO) write(10) Mesh Geometry write(10) dx dxlOOO write(lO) dy dylOOO write(lO) Number nodes in x-direction n1 write(lO) Number nodes in y-direction n2 write(lO) Number of steel skin nodes write(lO) (including corner 00) n5+l write(10) Steel nodes under the seal n3+1 ton3+n4 write(10) write(lO) Steel skin conductivity (Wm K) km write(lO) Foam insulation conductivity (Wm K) kins write(lO) Plastic skin conductivity (Wm K) kp write(lO) Outside h (Wm2 K) heffo write(lO) Inside h (Wm2 K) heffi
99
write(10) Outside Temp (C) To write(10) Inside Temp (C) Ti write(10) write (10 ) write(10) write(10) OUPUT PARAMETERS write (10 ) write(10) Number of iterations iter write(10) write(10) Heat Transfer for the Section write(10) OVerall Heat Transfer (W) Qin1 write(10) 10 Heat Flux Thru Wall (Wm2) q1D write (10 ) write(10) Heat Transfer Along Metal Skin Under Seal write(10) node to node qm[Wm2J Qm[WJ DO 135 i=n3+1n3+n4-1
write(10) i i+1 qfluxm(i) Qm(i) 135 CONTINUE
write (10 ) Maximum difference () abs (pmaxdif) write(10) IF (flag2 eq 1) THEN
write(10) The mesh does not extend far enough write(10) in the y-direction to reach 10 heat write(10) transfer for the specified tolerance write(10) ofoneDtol
ELSE write (10 ) Edge loss computed from qe=q2D-q1D qedge1 write (10 ) write(10) Edge loss computed directly from write(10) steel skin ~T at centerline qedge2
ENDIF write (10 ) write (10 ) write(10) Heat fluxes in thru the section write(10) along the centerline [Wm2J write (10 ) write(10) j flux 10 DO 136 j=Ojmax
write(10) j fluxcen(j) pfluxcen(j) 136 CONTINUE
PAUSE STOP END
C
SUBROUTINE sseqn (Trplusirminusirplusjrminusj i jimax jmax)
c This subroutine computes the temperature at node (ij) c given the temperatures of the surrounding nodes and c the resistances leading to these nodes
INTEGER ijimaxjmax REAL T(-1101-1101)rplusirminusirplusjrminusj REAL c1c2c3c4c5
c1=1rplusi c2=1rminusi c3=1rplusj c4=1rminusj c5=c1+c2+c3+c4
T(ij)=(1c5)(c1T(i+1j)+c2T(i-1j)+c3T(ij+1)+c4T(ij-1raquo
100
RETURN END
C
SUBROUTINE balance(TToTidxdyn3n4imaxjmaxQdifQpdif c Qin1Qin2r7r8r9r10r11b)
c This subroutine computes the steady-state heat balance c for the cross-section
INTEGER imaxjmaxijn3n4 REAL T(-1101-1101)TlToQin1Qin2dydx REAL r7r8r9r10r11b
c Compute the heat entering Qin1 [Wj Qin1=00 DO 10 jOjmax
Qin1=Qin1+(b(r7))(To-T(0j)) 10 CONTINUE
DO 20 i=0n3 Qin1=Qin1+(b(r8))(To-T(i0))
20 CONTINUE
c Compute the heat leaving Qin2 [Wj Qin2=00 DO 30 j=Ojmax
Qin2=Qin2+(b(r10))(T(imaxj)-Ti) 30 CONTINUE
DO 40 i=n3+n4+1imax IF (i le nS) then
Qin2=Qin2+(b(r9))(T(i0)-Ti) ELSE
Qin2=Qin2+(b(r11))(T(i0)-Ti) ENDIF
40 CONTINUE
c Compute the absolute difference in heat fluxes [Wj Qdif=abs(Qin2-Qin1)
c Compute the percent difference in the heat transfers [Wj Qpdif=(QdifQin1) 100
RETURN END
C
SUBROUTINE oneD (ToTiheffoheffikmkinskpdmdpslqlD)
c This subroutine compute the one-dimensional c heat flux through the section wall
INTEGER i REAL ToTiheffoheffikmkinskpdmdpsl REAL q1DReqdins
dins=sl-dm~dp
Req=(lheffo) + (dmkm) + (dinskins) +(dpkp)+(lheffi) q1D=(To-Ti)Req
RETURN END
101
F3 Fresh Food Wan Simulation Output
INPUT PARAMETERS
Section Dimensions (mm) Width 4500 Length 2000 Depth 1000 Steel skin thickness 6500 Plastic skin thickness 2500
Mesh Geometry dx 2250 dy 2500 Number nodes in x-direction 20 Number nodes in y-direction 80 Number of steel skin nodes (including corner 00) 11 Steel nodes under the seal 2 to 10
Steel skin conductivity (Wm K) 5400 Foam insulation conductivity (Wm K) 21000E-02 Plastic skin conductivity (Wm K) 1500 Outside h (Wm2 K) 6810 Inside h (Wm2 K) 6100 Outside Temp (C) 2100 Inside Temp (C) 4000
OUPUT PARAMETERS
Number of iterations 5318
10 Heat Flux Thru Wall (Wm2) 9132
Heat Transfer Along Metal Skin Under Seal node to node qm[Wm2] Qm[W]
2 3 1619 1092 3 4 1612 1081 4 5 1660 1019 5 6 1645 1010 6 1 1626 1051 1 8 1601 1041 8 9 1569 1020 9 10 1521 9922
Maximum difference () 9101
Edge loss computed directly from steel skin 1T at centerline 1645
Heat fluxes in thru the section along the centerline [Wm2]
j flux 10 0 4284 4691 1 2246 2459 2 3513 3841 3 4554 4981 4 5311 5881 5 6001 6512 6 6488 1104 1 6868 1520
102
10
20
30
40
50
60
70
8 7169 7850 9 7412 8117
7612 8335 11 7778 8517 12 7918 8670 13 8037 8800 14 8139 8912 15 8227 9008 16 8303 9092 17 8369 9164 18 8428 9228 19 8479 9285
8525 9334 21 8565 9379 22 8601 9418 23 8634 9454 24 8663 9486 25 8690 9515 26 8714 9542 27 8736 9566 28 8756 9588 29 8775 9609
8793 9628 31 8809 9645 32 8824 9662 33 8838 9677 34 8851 9692 35 8863 9705 36 8875 9718 37 8886 9730 38 8896 9742 39 8906 9752
8916 9763 41 8925 9772 42 8933 9782 43 8941 9791 44 8949 9799 45 8956 9807 46 8963 9815 47 8970 9822 48 8976 9829 49 8982 9836
8988 9842 51 8994 9848 52 8999 9854 53 9004 9859 54 9009 9864 55 9013 9869 56 9017 9874 57 9021 9878 58 9025 9883 59 9029 9887
9032 9890 61 9036 9894 62 9039 9897 63 9042 9901 64 9044 9903 65 9047 9906 66 9049 9909 67 9051 9911 68 9053 9913 69 9055 9915
9057 9917 71 9058 9919
103
72 9059 9920 73 9061 9921 74 9062 9922 75 9062 9923 76 9063 9924 77 9063 9924 78 9064 9925 79 9064 9925
j local Qwall [Wl
-1 3215 0 -45410E-02 1 -50708E-02 2 -40940E-02 3 -33836E-02 4 -27620E-02 5 -23180E-02 6 -1 9628E-02 7 -1 6076E-02 8 -1 4300E-02 9 -12524E-02 10 -10748E-02 11 -98601E-03 12 -89722E-03 13 -80842E-03 14 -71962E-03 15 -63081E-03 16 -63082E-03 17 -54202E-03 18 -54202E-03 19 -45322E-03 20 -45322E-03 21 -45322E-03 22 -45321E-03 23 -36442E-03 24 -36442E-03 25 -36442E-03 26 -27562E-03 27 -27561E-03 28 -27561E-03 29 -27561E-03 30 -27561E-03 31 -18682E-03 32 -18682E-03 33 -27561E-03 34 -18682E-03 35 -18682E-03 36 -18681E-03 37 -18682E-03 38 -98018E-04 39 -98018E-04 40 -98018E-04 41 -98018E-04 42 -98018E-04 43 -98018E-04 44 -98018E-04 45 -98018E-04 46 -98018E-04 47 -18682E-03 48 -98018E-04 49 -98018E-04 50 -98018E-04 51 -98018E-04 52 -98018E-04
104
53 -98018E-04 54 -92160E-05 55 -98018E-04 56 -98018E-04 57 -98018E-04 58 -98018E-04 59 -98018E-04 60 -92160E-05 61 -98018E-04 62 -92160E-05 63 -98018E-04 64 -98018E-04 65 -92160E-05 66 -98018E-04 67 -98018E-04 68 -92245E-05 69 -92245E-05 70 -98018E-04 71 -98018E-04 72 -98018E-04 73 -92160E-05 74 -92160E-05 75 -92160E-05 76 -92160E-05 77 -92160E-05 78 -92160E-05 79 -92160E-05
Qwallff [Wm21 = 1442 Qwallff [WI = 2775
Fresh Food Nodal Temperatures
x(mm) v(mm) 1125 3375 5625 7875 10125 12375 14625 16875 19125 21375
125 1761 1755 1748 1741 1734 1727 172 1713 1706 17 375 1768 1753 1738 1723 1707 169 1671 165 1624 1589 625 1775 1752 173 1706 1682 1656 1626 1593 1552 15 875 1781 1751 1722 1691 1659 1625 1587 1544 1494 1434
1125 -1787 1751 1715 1678 1639 1598 1553 1504 1448 1384 1375 1792 1751 1709 1667 1622 1576 1526 1471 1412 1346 1625 1798 1752 1705 1658 1609 1557 1503 1446 1384 ll17 1875 1803 1753 1702 165 1597 1543 1485 1425 1362 1294 2125 1808 1754 17 1645 1589 1531 1471 1409 1344 1276 2375 1813 1756 1699 1641 1582 1522 146 1396 133 1262 2625 1817 1758 1698 1638 1577 1515 1451 1386 132 1251 2875 1822 176 1698 1636 1573 151 1445 1379 1311 1242 3125 1826 1762 1699 1635 1571 1506 144 1373 1304 1235 3375 183 1765 17 1635 1569 1503 1436 1368 1299 1229 3625 1834 1768 1701 1635 1568 1501 1433 1364 1295 1225 3875 1837 177 1703 1635 1568 15 1431 1362 1292 1222 4125 1841 1773 1705 1636 1568 1499 143 136 129 1219 4375 1845 1776 1707 1638 1568 1499 1429 1359 1289 1218 4625 1848 1778 1709 1639 1569 1499 1429 1358 1288 1216 4875 1851 1781 1711 164 157 15 1429 1358 1287 1216 5125 1854 1784 1713 1642 1571 15 1429 1358 1287 1215 5375 1857 1786 1715 1644 1573 1501 143 1358 1287 1215 5625 186 1789 1717 1646 1574 1502 1431 1359 1287 1215
105
5875 1863 1791 1719 1647 1576 1504 1432 136 1288 1215 6125 1866 1794 1721 1649 1577 1505 1433 136 1288 1216 6375 1868 1796 1723 1651 1579 1506 1434 1361 1289 1216 6625 1871 1798 1725 1653 158 1508 1435 1362 129 1217 6875 1873 18 1727 1655 1582 1509 1436 1363 1291 1218 7125 1876 1803 1729 1656 1583 151 1437 1364 1291 1218 7375 1878 1805 1731 1658 1585 1512 1439 1366 1292 1219 7625 188 1807 1733 166 1587 1513 144 1367 1293 122 7875 1882 1809 1735 1661 1588 1515 1441 1368 1294 1221 8125 1884 181 1737 1663 159 1516 1442 1369 1295 1222 8375 1886 1812 1738 1665 1591 1517 1444 137 1296 1223 8625 1888 1814 174 1666 1592 1519 1445 1371 1297 1224 8875 189 1816 1742 1668 1594 152 1446 1372 1298 1225 9125 1892 1817 1743 1669 1595 1521 1447 1373 1299 1225 9375 1893 1819 1745 1671 1596 1522 1448 1374 13 1226 9625 1895 182 1746 1672 1598 1524 1449 1375 1301 1227 9875 1896 1822 1748 1673 1599 1525 145 1376 1302 1228 10125 1898 1823 1749 1674 16 1526 1451 1377 1303 1229 10375 1899 1825 175 1676 1601 1527 1452 1378 1304 123 10625 1901 1826 1751 1677 1602 1528 1453 1379 1305 123 10875 1902 1827 1753 1678 1603 1529 1454 138 1305 1231 11125 1903 1828 1754 1679 1604 153 1455 1381 1306 1232 11375 1904 183 1755 168 1605 1531 1456 1381 1307 1232 11625 1906 1831 1756 1681 1606 1532 1457 1382 1308 1233 11875 1907 1832 1757 1682 1607 1532 1458 1383 1308 1234 12125 1908 1833 1758 1683 1608 1533 1458 1384 1309 1234 12375 1909 1834 1759 1684 1609 1534 1459 1384 131 1235 12625 191 1835 176 1685 161 1535 146 1385 131 1235 12875 1911 1836 1761 1686 1611 1536 1461 1386 1311 1236 13125 1912 1837 1761 1686 1611 1536 1461 1386 1311 1236 13375 1913 1837 1762 1687 1612 1537 1462 1387 1312 1237 13625 1913 1838 1763 1688 1613 1538 1462 1387 1312 1237 13875 1914 1839 1764 1688 1613 1538 1463 1388 1313 1238 14125 1915 184 1764 1689 1614 1539 1464 1388 1313 1238 14375 1916 184 1765 169 1614 1539 1464 1389 1314 1239 14625 1916 1841 1766 169 1615 154 1465 1389 1314 1239 14875 1917 1842 1766 1691 1616 154 1465 139 1315 1239 15125 1918 1842 1767 1691 1616 1541 1465 139 1315 124 15375 1918 1843 1767 1692 1616 1541 1466 1391 1315 124 15625 1919 1843 1768 1692 1617 1542 1466 1391 1316 124 15875 1919 1844 1768 1693 1617 1542 1467 1391 1316 1241 16125 192 1844 1769 1693 1618 1542 1467 1392 1316 1241 16375 192 1844 1769 1694 1618 1543 1467 1392 1317 1241 16625 192 1845 1769 1694 1618 1543 1468 1392 1317 1241 16875 1921 1845 177 1694 1619 1543 1468 1392 1317 1242 17125 1921 1846 177 1694 1619 1544 1468 1393 1317 1242 17375 1921 1846 177 1695 1619 1544 1468 1393 1317 1242 17625 1922 1846 1771 1695 1619 1544 1469 1393 1318 1242 17875 1922 1846 1771 1695 162 1544 1469 1393 1318 1242 18125 1922 1847 1771 1695 162 1544 1469 1393 1318 1243 18375 1922 1847 1771 1696 162 1545 1469 1394 1318 1243 18625 1923 1847 1771 1696 162 1545 1469 1394 1318 1243 18875 1923 1847 1771 1696 162 1545 1469 1394 1318 1243 19125 1923 1847 1772 1696 162 1545 1469 1394 1318 1243 19375 1923 1847 1772 1696 162 1545 1469 1394 1318 1243 19625 1923 1847 1772 1696 1621 1545 1469 1394 1318 1243 19875 1923 1847 1772 1696 1621 1545 1469 1394 1318 1243
106
x(mm) y(mm) 23625 25875 28125 30375 32625 34875 37125 39375 41625 43875
125 1694 1662 1287 1033 8577 7336 6444 5795 5324 4995 375 1536 144 125 1068 9163 7946 6974 6189 5532 4944 625 1431 1334 1203 1066 9379 8252 7275 6423 5657 4935 875 136 127 1164 1051 9408 8374 7423 6548 573 4941
1125 131 1226 1132 1034 9353 8394 7477 6605 5766 4948 1375 1273 1193 1107 1017 9262 836 7478 6618 5779 4952 1625 1245 1168 1086 1002 9162 8302 7449 6607 5776 4951 1875 1223 1148 1069 9886 9064 8236 7408 6583 5764 4948 2125 1205 1132 1055 977 8974 8169 7362 6554 5747 4941 2375 1191 1119 1044 9671 8893 8107 7316 6522 5728 4933 2625 118 1108 1034 9588 8824 8051 7273 6492 5709 4925 2875 1172 11 1026 9518 8764 8002 7235 6464 5691 4916 3125 1164 1093 102 946 8713 796 7201 6439 5674 4908 3375 1159 1087 1015 9412 8671 7924 7172 6417 566 49 3625 1154 1083 101 9373 8636 7894 7148 6399 5647 4894 3875 1151 1079 1007 9341 8608 7869 7128 6383 5636 4888 4125 1148 1077 1004 9316 8585 7849 7111 637 5627 4883 4375 1146 1074 1002 9296 8566 7833 7097 6359 5619 4879 4625 1145 1073 1001 9281 8552 7821 7087 6351 5613 4875 4875 1144 1072 9995 927 8541 7811 7078 6344 5609 4872 5125 1143 1071 9987 9261 8533 7803 7072 6339 5605 487 5375 1143 1071 9982 9256 8528 7798 7067 6335 5602 4868 5625 1143 107 9979 9253 8524 7795 7064 6332 56 4867 5875 1143 107 9978 9251 8522 7793 7062 6331 5599 4866 6125 1143 1071 9979 9251 8522 7792 7061 633 5598 4866 6375 1144 1071 9981 9252 8523 7792 7061 633 5598 4865 6625 1144 1071 9984 9255 8524 7793 7062 633 5598 4865 6875 1145 1072 9988 9258 8526 7795 7063 6331 5598 4865 7125 1145 1072 9993 9261 8529 7797 7065 6332 5599 4866 7375 1146 1073 9998 9265 8533 78 7067 6333 56 4866 7625 1147 1074 10 927 8536 7803 7069 6335 5601 4867 7875 1148 1074 1001 9275 854 7806 7072 6337 5602 4867 8125 1148 1075 1001 928 8545 7809 7074 6339 5603 4868 8375 1149 1076 1002 9285 8549 7813 7077 6341 5605 4869 8625 115 1076 1003 929 8553 7817 708 6343 5606 4869 8875 1151 1077 1003 9295 8558 782 7083 6345 5608 487 9125 1152 1078 1004 93 8562 7824 7086 6347 5609 4871 9375 1152 1078 1004 9306 8567 7828 7089 635 5611 4872 9625 1153 1079 1005 9311 8571 7831 7092 6352 5612 4873 9875 1154 108 1006 9316 8575 7835 7094 6354 5614 4873 10125 1155 108 1006 9321 858 7838 7097 6356 5615 4874 10375 1155 1081 1007 9326 8584 7842 71 6358 5617 4875 10625 1156 1082 1007 933 8588 7845 7103 636 5618 4876 10875 1157 1082 1008 9335 8592 7848 7105 6362 5619 4876 11125 1157 1083 1008 9339 8596 7852 7108 6364 5621 4877 11375 1158 1083 1009 9344 8599 7855 711 6366 5622 4878 11625 1158 1084 1009 9348 8603 7858 7113 6368 5623 4879 11875 1159 1084 101 9352 8606 7861 7115 637 5625 4middot879 12125 116 1085 101 9356 861 7864 7117 6372 5626 488 12375 116 1085 1011 936 8613 7866 712 6373 5627 488 12625 1161 1086 1011 9363 8616 7869 7122 6375 5628 4881 12875 1161 1086 1011 9367 8619 7871 7124 6376 5629 4882 13125 1162 1087 1012 937 8622 7874 7126 6378 563 4882 13375 1162 1087 1012 9373 8625 7876 7128 6379 5631 4883 13625 1162 1087 1013 9376 8627 7878 7129 6381 5632 4883
107
13875 1163 1088 1013 9379 863 788 7131 6382 5633 4884 14125 1163 1088 1013 9382 8632 7882 7133 6383 5634 4884 14375 1164 1089 1013 9384 8634 7884 7134 6384 5634 4885 14625 1164 1089 1014 9387 8636 7886 7136 6385 5635 4885 14875 1164 1089 1014 9389 8638 7888 7137 6386 5636 4885 15125 1165 1089 1014 9392 864 7889 7138 6387 5637 4886 15375 1165 109 1015 9394 8642 7891 714 6388 5637 4886 15625 1165 109 1015 9396 8644 7892 7141 6389 5638 4886 15875 1165 109 1015 9398 8646 7894 7142 639 5638 4887 16125 1166 109 1015 9399 8647 7895 7143 6391 5639 4887 16375 1166 1091 1015 9401 8649 7896 7144 6392 5639 4887 16625 1166 1091 1016 9403 865 7897 7145 6392 564 4888 16875 1166 1091 1016 9404 8651 7898 7146 6393 564 4888 17125 1167 1091 1016 9405 8652 7899 7146 6394 5641 4888 17375 1167 1091 1016 9406 8653 79 7147 6394 5641 4888 17625 1167 1091 1016 9407 8654 7901 7148 6395 5641 4888 17875 1167 1092 1016 9408 8655 7902 7148 6395 5642 4889 18125 1167 1092 1016 9409 8656 7902 7149 6395 5642 4889 18375 1167 1092 1016 941 8656 7903 7149 6396 5642 4889 18625 1167 1092 1016 9411 8657 7903 715 6396 5642 4889 18875 1167 1092 1017 9411 8657 7904 715 6396 5643 4889 19125 1167 1092 1017 9412 8658 7904 715 6396 5643 4889 19375 1167 1092 1017 9412 8658 7904 715 6397 5643 4889 19625 1167 1092 1017 9412 8658 7904 715 6397 5643 4889 19875 1168 1092 1017 9412 8658 7904 715 6397 5643 4889
F4 Freezer Wall Simulation Output
INPUT PARAMETERS
Section Dimensions (mm) Width 5600 Length 2000 Depth 1000 Steel skin thickness 6500 Plastic skin thickness 2500
Mesh Geometry dx 2800 dy 2500 Number nodes in x-direction 20 Number nodes in y-direction 80 Number of steel skin nodes (including corner 00) 9 Steel nodes under the seal 2 to 8
Steel skin conductivity (Wm K) 5400 Foam insulation conductivity (Wm K) 27000E-02 Plastic skin conductivity (Wm K) 1500 Outside h (Wm2 K) 6870 Inside h (Wm2 K) 6410 Outside Temp (C) 2100 Inside Temp (C) -1000
OUPUT PARAMETERS
108
Number of iterations 5409
Heat Transfer for the Section OVerall Heat Transfer (WI 4518 10 Heat Flux Thru Wall (Wm21 1362
Heat Transfer Along Metal Skin Under Seal node to node
2 3 3 4 4 5 5 6 6 7 7 8
Maximum difference
qm[Wm2) Om(W) 3026 1967 3008 1955 2981 1938 2944 1914 2892 1880 2820 1833
(1 6799
Edge loss computed from qe=q20-q1D 1760
Edge loss compusteel skin AT
ted directly from at centerline 2981
Heat fluxes in thru the section along the centerline [Wm2)
j flux UO 0 7762 5698 1 3711 2724 2 5678 41 68 3 7275 5341 4 8508 6246 5 9437 6927 6 1013 7438 7 1066 7823 8 1106 8117 9 1137 8347 10 1162 8529 11 1182 8678 12 1199 8801 13 1213 8904 14 1225 8992 15 1235 9068 16 1244 9135 17 1252 9193 18 1259 9245 19 1266 9291 20 1271 9333 21 1276 9370 22 1281 9405 23 1285 9436 24 1289 9464 25 1293 9491 26 1296 9515 27 1299 9538 28 1302 9559 29 1305 9578 30 1307 9596 31 1310 9614 32 1312 9630 33 1314 9645 34 1316 9659 35 1318 9673 36 1319 9685 37 1321 9697
109
38 1323 9709 39 1324 9720 40 1325 9730 41 1327 9740 42 1328 9749 43 1329 9758 44 1330 9767 45 1332 9775 46 1333 9783 47 1334 97bull 90 48 1335 9797 49 1336 9804 50 1336 9810 51 1337 9816 52 1338 9822 53 1339 9828 54 1340 9833 55 1340 9838 56 1341 9843 57 1341 9847 58 1342 9852 59 1343 9856 60 1343 9859 61 1344 9863 62 1344 9866 63 1344 9870 64 1345 9873 65 1345 9875 66 1346 9878 67 1346 9880 68 1346 9882 69 1347 9884 70 1347 9886 71 1347 9888
72 1347 9889 73 1347 9891 74 1347 9892 75 1348 9893 76 1348 9893 77 1348 9894 78 1348 9894 79 1348 9894
j local Qwall [WI
-1 3067 0 -36774E-02 1 -40214E-02 2 -32314E-02 3 -25994E-02 4 -20859E-02 5 -16909E-02 6 -14144E-02 7 -12169E-02 8 -10589E-02 9 -90092E-03 10 -78242E-03 11 -70342E-03 12 -66392E-03 13 -58492E-03 14 -54542E-03 15 -50592E-03 16 -46642E-03 17 -42692E-03 18 -42692E-03
110
19 -38742E-03 20 -34792E-03 21 -30842E-03 22 -30842E-03 23 -30842E-03 24 -26892E-03 25 -26892E-03 26 -22942E-03 27 -22942E-03 28 -22942E-03 29 -22942E-03 30 -18992E-03 31 -1 8992E-03 32 -18992E-03 33 -18992E-03 34 -1 8992E-03 35 -1 5042E-03 36 -1 8992E-03 37 -15042E-03 38 -1 5042E-03 39 -11092E-03 40 -11092E-03 41 -11092E-03 42 -11092E-03 43 -11092E-03 44 -11092E-03 45 -11092E-03 46 -11092E-03 47 -71417E-04 48 -11092E-03 49 -71421E-04 50 -11092E-03 51 -71417E-04 52 -11092E-03 53 -71417E-04 54 -71421E-04 55 -71421E-04 56 -71417E-04 57 -31916E-04 58 -31920E-04 59 -31916E-04 60 -31916E-04 61 -71417E-04 62 -11421E-04 63 -71421E-04 64 -31920E-04 65 -31920E-04 66 -71417E-04 67 -31916E-04 68 -71417E-04 69 -31920E-04 70 -71421E-04 71 -31920E-04 72 -31920E-04 73 -71417E-04 74 -31916E-04 75 -31916E-04 76 -31916E-04 77 -31916E-04 78 -71417E-04 79 -71417E-04
Qwallfz [Wm2J = 2895 Qwallfz [WJ = 2721
111
Freezer Wan Nodal Temperatures
x(mm) y1mm 14 42 70 98 126 154 182 210 238 266
125 1507 1492 1477 1461 1445 143 1415 14 1385 1338 375 1519 1489 1458 1426 1392 1353 1307 1247 1154 972 625 1531 1486 1441 1393 1341 1282 1212 1121 9925 7989 875 1542 1484 1425 1363 1296 1221 1132 1023 8837 7014
1125 1553 1483 1412 1338 1258 117 1069 9508 809 6396 1375 1563 1483 1401 1317 1227 1129 102 8969 7563 5974 1625 1572 1483 1393 13 1202 1097 9824 8568 7184 5673 1875 1582 1485 1387 1287 1182 1072 9537 8269 6906 5452 2125 1591 1488 1384 1277 1167 1053 9321 8046 67 5288 2375 1599 1491 1382 1271 1157 1039 916 7881 6547 5164 2625 1608 1495 1381 1266 1149 1028 9041 7758 6433 5071 2875 1616 1499 1382 1264 1144 1021 8955 7668 6349 5002 3125 1623 1504 1384 1263 114 1016 8895 7604 6288 495 3375 1631 1509 1386 1263 1139 1013 8854 7559 6245 4913 3625 1638 1514 1389 1264 1138 1011 8829 753 6216 4888 3875 1645 1519 1393 1266 1139 1011 8816 7513 6198 4872 4125 1652 1524 1396 1269 114 1011 8813 7505 6188 4863 4375 1658 1529 14 1271 1142 1012 8817 7505 6185 486 4625 1664 1534 1405 1275 1144 1014 8826 751 6188 4861 4875 167 1539 1409 1278 1147 1016 884 752 6195 4867 5125 1676 1544 1413 1281 115 1018 8858 7533 6206 4875 5375 1682 1549 1417 1285 1153 102 8877 755 6219 4886 5625 1687 1554 1421 1289 1156 1023 8899 7568 6235 4899 5875 1692 1559 1425 1292 1159 1026 8923 7588 6252 4914 6125 1698 1563 143 1296 1162 1028 8947 7609 627 493 6375 1702 1568 1434 1299 1165 1031 8972 763 6289 4946 6625 1707 1572 1438 1303 1169 1034 8997 7653 6308 4964 6875 1712 1576 1441 1306 1172 1037 9022 7675 6329 4982 7125 1716 158 1445 131 1175 104 9048 7698 6349 5 7375 172 1584 1449 1313 1178 1043 9073 7721 6369 5018 7625 1724 1588 1452 1317 1181 1045 9098 7744 639 5036 7875 1728 1592 1456 132 1184 1048 9123 7766 641 5054 8125 1732 1595 1459 1323 1187 1051 9147 7788 643 5072 8375 1736 1599 1462 1326 1189 1053 917 781 645 509 8625 1739 1602 1465 1329 1192 1056 9194 7831 6469 5108 8875 1743 1605 1468 1332 1195 1058 9216 7852 6488 5125 9125 1746 1609 1471 1334 1197 1061 9238 7872 6507 5142 9375 1749 1612 1474 1337 12 1063 926 7892 6525 5158 9625 1752 1615 1477 134 1202 1065 9281 7911 6542 5174 9875 1755 1617 148 1342 1205 1067 9301 793 656 519 10125 1758 162 1482 1344 1207 1069 9321 7948 6576 5205 10375 1761 1623 1485 1347 1209 1071 934 7966 6593 522 10625 1763 1625 1487 1349 1211 1073 9358 7983 6608 5234 10875 1766 1627 1489 1351 1213 1075 9376 7999 6623 5248 11125 1768 163 1491 1353 1215 1077 9393 8015 6638 5262 11375 1771 1632 1494 1355 1217 1079 941 8031 6652 5275 11625 1773 1634 1496 1357 1219 1081 9426 8045 6666 5287 11875 1775 1636 1498 1359 1221 1082 9441 806 6679 53 12125 1777 1638 1499 1361 1222 1084 9456 8073 6692 5311 12375 1779 164 1501 1362 1224 1085 947 8087 6704 5322 12625 1781 1642 1503 1364 1225 1087 9483 8099 6716 5333 12875 1783 1644 1505 1366 1227 1088 9496 8111 6727 5344
112
13125 1784 1645 1506 1367 1228 109 9509 8123 6738 5353 13375 1786 1647 1508 1369 123 1091 9521 8134 6748 5363 13625 1788 1648 1509 137 1231 1092 9532 8145 6758 5372 13875 1789 165 151 1371 1232 1093 9543 8155 6768 5381 14125 1791 1651 1512 1373 1233 1094 9554 8165 6777 5389 14375 1792 1652 1513 1374 1235 1095 9564 8174 6785 5397 14625 1793 1654 1514 1375 1236 1096 9573 8183 6793 5404 14875 1794 1655 1515 1376 1237 1097 9582 8191 6801 5412 15125 1796 1656 1516 1377 1238 1098 959 8199 6808 5418 15375 1797 1657 1517 1378 1238 1099 9598 8206 6815 5425 15625 1798 1658 1518 1379 1239 11 9606 8213 6822 5431 15875 1799 1659 1519 138 124 1101 9613 822 6828 5436 16125 18 166 152 138 1241 1101 9619 8226 6834 5442 16375 18 1661 1521 1381 1242 1102 9626 8232 6839 5446 16625 1801 1661 1521 1382 1242 1103 9631 8237 6844 5451 16875 1802 1662 1522 1382 1243 1103 9637 8242 6848 5455 17125 1803 1663 1523 1383 1243 1104 9642 8247 6853 5459 17375 1803 1663 1523 1384 1244 1104 9646 8251 6857 5463 17625 1804 1664 1524 1384 1244 1105 965 8255 686 5466 17875 1804 1664 1524 1384 1245 1105 9654 8258 6863 5469 18125 1805 1665 1525 1385 1245 1105 9657 8261 6866 5471 18375 1805 1665 1525 1385 1245 1106 966 8264 6869 5474 18625 1805 1665 1525 1385 1246 1106 9662 8266 6871 5476 18875 1806 1666 1526 1386 1246 1106 9664 8268 6872 5477 19125 1806 1666 1526 1386 1246 1106 9666 827 6874 5479 19375 1806 1666 1526 1386 1246 1106 9667 8271 6875 548 19625 1806 1666 1526 1386 1246 1107 9668 8271 6876 548 19875 1806 1666 1526 1386 1246 1107 9668 8272 6876 5481
x(mm) v(mm) 294 322 350 378 406 434 462 490 518 546
125 549 054 -27 -5 -624 -727 -8 -85 -89 -92 375 548 171 -12 -338 -5 -624 -719 -795 -858 -914 625 51 22 -032 -24 -408 -543 -654 -748 -83 -907 875 474 238 0182 -175 -34 -482 -603 -71 -807 -898
1125 445 243 048 -132 -293 -436 -564 -68 -787 -89 1375 423 243 0653 -103 -259 -402 -534 -656 -772 -883 1625 406 24 0752 -084 -236 -378 -511 -638 -759 -877 1875 393 237 0808 -071 -219 -36 -495 -624 -749 -871 2125 382 233 0837 -063 -208 -348 -483 -614 -741 -867 2375 374 23 085 -058 -2 -339 -474 -606 -735 -863 2625 368 227 0855 -055 -195 -332 -467 -6 -731 -86 2875 363 225 0855 -053 -191 -328 -462 -596 -728 -858 3125 36 223 0853 -052 -189 -324 -459 -593 -725 -856 3375 357 221 0851 -051 -187 -322 -457 -59 -723 -855 3625 355 22 0849 -05 -186 -32 -455 -588 -722 -854 3875 354 219 0849 -049 -185 -319 -453 -587 -72 -853 4125 353 219 0849 -049 -184 -318 -452 -586 -72 -853 4375 353 219 0852 -049 -183 -317 -451 -585 -719 -852 4625 353 219 0855 -048 -183 -317 -451 -584 -718 middot852 4875 353 22 0861 -047 -182 -316 -45 -584 -718 -852 5125 354 22 0867 -047 -181 -315 -449 -584 -717 -851 5375 355 221 0875 -046 -181 -315 -449 -583 -717 -851 5625 356 222 0884 -045 -18 -314 -448 -582 -717 -851 5875 358 223 0894 -044 -179 -313 -448 -582 -716 -851 6125 359 225 0904 -043 -178 -313 -447 -582 -716 -851 6375 36 226 0915 -043 -177 -312 -447 -581 -716 -85
113
6625 362 227 0927 -042 -177 -311 -446 -581 -716 -85 6875 363 229 0939 -04 -176 -311 -445 -58 -715 -85 7125 365 23 0951 -039 -175 -31 -445 -58 -715 -85 7375 367 232 0964 -038 -174 -309 -444 -579 -715 -85 7625 368 233 0976 -037 -173 -308 -444 -579 -714 -85 7875 37 234 0989 -036 -172 -308 -443 -578 -714 -849 8125 371 236 1 -035 -171 -307 -442 -578 -714 -849 8375 373 237 101 -034 -17 -306 -442 -578 -713 -849 8625 375 239 103 -033 -169 -305 -441 -577 -713 -849 8875 376 24 104 -032 -168 -305 -441 -577 -713 -849 9125 378 241 105 -031 -168 -304 -44 -576 -712 -849 9375 379 243 106 -03 -167 -303 -439 -576 -712 -848 9625 381 244 107 -029 -166 -302 -439 -575 -712 -848 9875 382 245 109 -028 -165 -302 -438 -575 -712 -848 10125 384 246 11 -027 -164 -301 -438 -574 -711 -848 10375 385 248 111 -026 -163 -3 -437 -574 -711 -848 10625 386 249 112 -025 -163 -3 -437 -574 -711 -848 10875 387 25 113 -024 -162 -299 -436 -573 -711shy -848 11125 389 251 114 -023 -161 -298 -436 -573 -71 -848 11375 39 252 115 -022 -16 -298 -435 -573 -71 -847 11625 391 253 115 -022 -16 -297 -435 -572 -71 -847 11875 392 254 116 -021 -159 -297 -434 -572 -709 -847 12125 393 255 117 -02 -158 -296 -434 -572 -709 -847 12375 394 256 118 -019 -158 -296 -434 -571 -709 -847 12625 395 257 119 -019 -157 -295 -433 -571 -709 -847 12875 396 258 12 -018 -157 -295 -433 -571 -709 -847 13125 397 259 12 -017 -156 -294 -432 -57 -709 -847 13375 398 259 121 -017 -155 -294 -432 -57 -708 -847 13625 399 26 122 -016 -155 -293 -432 -57 -708 -846 13875 399 261 122 -016 -154 -293 -431 -57 -708 -846 14125 4 262 123 -015 -154 -292 -431 -569 -708 -846 14375 401 262 124 -015 -154 -292 -431 -569 -708 -846 14625 402 263 124 -014 -153 -292 -43 -569 -707 -846 14875 402 263 125 -014 -153 -291 -43 -569 -707 -846 15125 403 264 125 -013 -152 -291 -43 -569 -707 -846 15375 403 264 126 -013 -152 -291 -43 -568 -707 -846 15625 404 265 126 -012 -152 -291 -429 -568 -707 -846 15875 405 265 126 -012 -151 -29 -429 -568 -707 -846 16125 405 266 127 -012 -151 -29 -429 -568 -707 -846 16375 405 266 127 -011 -151 -29 -429 -568 -707 -846 16625 406 267 128 -011 -151 -29 -429 -568 -707 -846 16875 406 267 128 -011 -15 -289 -428 -568 -707 -845 17125 407 267 128 -01 -15 -289 -428 -567 -706 -845 17375 407 268 128 -01 -15 -289 -428 -567 -706 -845 17625 407 268 129 -01 -15 -289 -428 -567 -706 -845 17875 407 268 129 -01 -15 -289 -428 -567 -706 -845 18125 408 268 129 -01 -15 -289 -428 -567 -706 -845 18375 408 269 129 -01 -149 -289 -428 -567 -706 -845 18625 408 269 129 -001 -149 -288 -428 -567 -706 -845 18875 408 269 129 -001 -149 -288 -428 -567 -706 -845 19125 408 269 13 -001 -149 -288 -428 -567 -706 -845 19375 409 269 13 -001 -149 -288 -428 -567 -706 -845 19625 409 269 13 -001 -149 -288 -428 -567 -706 -845 19875 409 269 13 -001 -15 -288 -428 -567 -706 -845
114
FS Fresh Food Wan Simulation Output Including Anti-sweat Condenser Tube
INPUT PARAMETERS
Section Dimensions (mm) Hidth 4500 Length 2000 Depth 2960 Steel skin thickness 6500 Plastic skin thickness 2500
Mesh Geometry dx 2250 dy 2500 Number nodes in x-direction 20 Number nodes in y-direction 80 Number of steel skin nodes (including corner 00) 11 Steel nodes under the seal 2 to 10 Tube located at node 6
Steel skin conductivity (Him K) 5400 Foam insulation conductivity (Him K) 27000E-02 Plastic skin conductivity (Him K) 1500 Outside h (Hm2 K) 6870 Inside h (Hm2 K) 6700 Outside Temp (C) 2100 Inside Temp (C) 4000
OUPUT PARAMETERS
Number of iterations 602
10 Heat Flux Thru Hall (Hm2) 9132
Heat Transfer Along Metal Skin Under Seal node to node qm[Hm21 Qm[HI
2 3 -15052E+04 -2896 3 4 -15125E+04 -2910 4 5 -15198E+04 -2924 5 6 -15274E+04 -2939 6 7 3996 7688 7 8 3898 7500 8 9 3790 7292 9 10 3662 7045
Maximum difference () 1243
j qleft [HI qright [HI -1 -2957 7832 0 -92065E-02 -38838E-02 1 -77348E-02 -48044E-02 2 -51596E-02 -30284E-02 3 -32948E-02 -15188E-02 4 -1 9628E-02 -54201E-03 5 -98600E-03 16837E-03 6 -36442E-03 70ll8E-03 7 79586E-04 96757E-03 8 43478E-03 11452E-02 9 70118E-03 12340E-02 10 87877E-03 12340E-02
115
11 87879E-03 13228E-02 12 10564E-02 12340E-02 13 10564E-02 11452E-02 14 96759E-03 11452E-02 15 87877E-03 10564E-02 16 87879E-03 87877E-03 17 78999E-03 87877E-03 18 61238E-03 78999E-03 19 61240E-03 61237E-03 20 52359E-03 52358E-03 21 34598E-03 34598E-03 22 25719E-03 25717E-03 23 16838E-03 16839E-03 24 79586E-04 25 -98018E-04 26 -18681E-03 27 -27561E-03 28 -36442E-03 29 -54202E-03 30 -54202E-03 31 -7 1962E-03 32 -80842E-03 33 -8 9721E-03 34 -98602E-03 35 -10748E-02 36 -11636E-02 37 -12524E-02 38 -1 3412E-02 39 -1 4300E-02 40 -15188E-02 41 -1 5188E-02 42 -1 6076E-02 43 -16964E-02 44 -17852E-02 45 -1 7852E-02 46 -1 8740E-02 47 -19628E-02 48 -19628E-02 49 -19628E-02 50 -20516E-02 51 -21404E-02 52 -22292E-02 53 -22292E-02 54 -23180E-02 55 -23180E-02 56 -23180E-02 57 -24068E-02
79578E-04 -98018E-04 -1 8682E-03 -27561E-03 -45322E-03 -54202E-03 -71962E-03 -71962E-03 -8 9722E-03 -8 9722E-03 -10748E-02 -11636E-02 -12524E-02 -13412E-02 -14300E-02 -1 5188E-02 -16076E-02 -16964E-02 -16964E-02 -17852E-02 -18740E-02 -19628E-02 -20516E-02 -20516E-02 -21404E-02 -22292E-02 -22470E-02 -22381E-02 -22647E-02 -23358E-02 -23447E-02 -23802E-02 -24512E-02 -24690E-02
58 -23979E-02 -25223E-02 59 -24423E-02 60 -24246E-02 61 -24423E-02 62 -24779E-02 63 -25400E-02 64 -25400E-02 65 -25667E-02 66 -26199E-02 67 -26022E-02 68 -26111E-02 69 -26377E-02 70 -26022E-02 71 -26732E-02 72 -26821E-02 73 -26199E-02 74 -26643E-02
-25489E-02 -25755E-02 -25933E-02 -2 6199E-02 -26466E-02 -26643E-02 -26821E-02 -26910E-02 -27087E-02 -27265E-02 -27354E-02 -27443E-02 -27531E-02 -27620E-02 -27620E-02 -27709E-02
116
75 -26377E-02 -27709E-02 76 -26377E-02 -27709E-02 77 -26555E-02 -27709E-02 78 -26910E-02 -27620E-02 79 -26555E-02 -27620E-02
Qleft [ii] -3079 Qright [ii] 6756 Percent entering cabinet 1800
Fresh Food Nodal Temperatures (Condenser Tube)
x(mm) y(mm) 1125 3375 5625 7875 10125 12375 14625 16875 19125 21375
19875 126 1206 1154 1104 1055 1007 9608 9158 872 8294 19625 1259 1205 1153 1103 1054 1006 9602 9152 8715 8289 19375 1259 1205 1153 1102 1053 1006 9598 9149 8711 8285 19125 1259 1205 1153 1102 1053 1006 9596 9147 871 8284 18875 1259 1205 1153 1102 1053 1006 9596 9147 871 8284 18625 1259 1205 1153 1103 1054 1006 9599 915 8712 8286 18375 126 1206 1154 1103 1054 1007 9604 9154 8716 829 18125 1261 1207 1155 1104 1055 1007 9611 9161 8722 8295 17875 1263 1209 1156 1105 1056 1008 962 9169 873 8302 17625 1264 121 1158 1107 1058 101 9632 918 874 8311 17375 1266 1212 116 1109 1059 1011 9646 9193 8752 8322 17125 1269 1215 1162 1111 1061 1013 9663 9209 8766 8335 16875 1272 1217 1164 1113 1063 1015 9682 9226 8783 835 16625 1275 122 1167 1116 1066 1017 9704 9246 8801 8367 16375 1279 1224 117 1119 1069 102 9728 9269 8822 8386 16125 1282 1227 1174 1122 1072 1023 9755 9294 8845 8407 15875 1287 1231 1178 1126 1075 1026 9785 9322 887 843 15625 1292 1236 1182 113 1079 103 9818 9352 8898 8456 15375 1297 1241 1187 1134 1083 1034 9854 9385 8929 8484 15125 1302 1246 1192 1139 1088 1038 9892 9421 8962 8514 14875 1308 1252 1197 1144 1092 1042 9934 946 8998 8547 14625 1315 1258 1203 1149 1097 1047 9979 9502 9037 8583 14375 1322 1265 1209 1155 1103 1052 1003 9547 9078 8621 14125 1329 1272 1216 1162 1109 1058 1008 9595 9123 8662 13875 1337 1279 1223 1168 1115 1064 1014 9647 9171 8706 13625 1346 1287 1231 1176 1122 107 102 9703 9222 8753 13375 1355 1296 1239 1183 1129 1077 1026 9762 9277 8803 13125 1364 1305 1247 1191 1137 1084 1033 9824 9335 8856 12875 1374 1314 1256 12 1145 1092 104 9891 9396 8913 12625 1385 1325 1266 1209 1154 11 1047 9962 9462 8973 12375 1396 1335 1276 1219 1163 1109 1055 1004 9531 9037 12125 1408 1347 1287 1229 1173 1118 1064 1012 9605 9105 11875 1421 1359 1299 124 1183 1127 1073 102 9683 9176 11625 1434 1371 1311 1251 1194 1137 1082 1029 9765 9252 11375 1448 1385 1323 1263 1205 1148 1092 1038 9851 9332 11125 1462 1399 1336 1276 1217 1159 1103 1048 9943 9416 10875 1478 1413 135 1289 1229 1171 1114 1058 1004 9505 10625 1494 1429 1365 1303 1243 1184 1126 1069 1014 9598 10375 1511 1445 138 1318 1257 1197 1138 1081 1025 9696 10125 1528 1462 1397 1333 1271 121 1151 1093 1036 98 9875 1547 1479 1413 1349 1286 1225 1165 1106 1048 9908 9625 1566 1498 1431 1366 1302 124 1179 1119 106 1002
117
9375 1586 1517 145 1384 1319 1256 1194 1133 1073 1014 9125 1607 1537 1469 1402 1336 1272 1209 1147 1087 1027 8875 1629 1558 1489 1421 1355 129 1226 1163 1101 104 8625 1652 158 151 1441 1374 1308 1243 1179 1116 1054 8375 1676 1603 1532 1462 1394 1327 1261 1195 1131 1068 8125 17 1627 1555 1484 1415 1346 1279 1213 1148 1084 7875 1726 1652 1579 1507 1436 1367 1299 1231 1165 11 7625 1753 1678 1604 1531 1459 1389 1319 1251 1183 1116 7375 1781 1704 1629 1556 1483 1411 1341 1271 1202 1134 7125 1809 1732 1656 1581 1508 1435 1363 1292 1222 1152 6875 1839 1761 1684 1608 1533 146 1387 1314 1243 1172 6625 187 1791 1713 1636 156 1485 1411 1337 1264 1192 6375 1903 1823 1744 1666 1589 1512 1437 1362 1287 1214 6125 1936 1855 1775 1696 1618 1541 1464 1387 1312 1236 5875 197 1889 1808 1728 1649 157 1492 1414 1337 126 5625 2006 1923 1842 1761 1681 1601 1522 1443 1364 1285 5375 2043 196 1877 1795 1714 1633 1553 1473 1392 1312 5125 2081 1997 1914 1832 1749 1668 1586 1504 1422 134 4875 212 2036 1952 1869 1786 1704 1621 1538 1454 137 4625 2161 2076 1992 1909 1825 1741 1658 1573 1488 1403 4375 2203 2118 2034 195 1866 1782 1697 1611 1525 1437 4125 2246 2161 2077 1993 1909 1824 1738 1652 1564 1474 3875 229 2206 2123 2039 1955 1869 1783 1695 1606 1515 3625 2336 2253 217 2087 2003 1918 1831 1742 1651 1558 3375 2383 2302 222 2138 2055 197 1882 1793 1701 1606 3125 2432 2353 2273 2192 211 2026 1938 1848 1755 1658 2875 2482 2405 2328 225 217 2086 20 1909 1815 1715 2625 2533 2461 2387 2312 2234 2153 2067 1977 1881 178 2375 2586 2518 2449 2378 2304 2226 2142 2052 1955 1851 2125 264 2579 2516 2451 2381 2306 2225 2136 2039 1933 1875 2696 2642 2587 2529 2466 2396 2319 2232 2134 2026 1625 2753 2709 2664 2614 256 2497 2425 2341 2244 2133 1375 2811 278 2746 2708 2664 2611 2546 2468 2373 226 1125 2871 2854 2835 2811 278 2739 2685 2615 2524 2411 875 2932 2932 293 2923 2909 2885 2846 2787 2706 2595 625 2995 3014 3031 3045 3052 3049 3031 2989 2922 2824 375 3058 3098 3138 3175 3208 3234 3245 3223 3179 3109 125 3124 3185 3247 331 3373 3436 35 3483 3467 3451
x(mm) y(mm) 23625 25875 28125 30375 32625 34875 37125 39375 41625 43875
19875 7877 747 7071 6679 6294 5915 554 5168 4799 4432 19625 7872 7466 7067 6676 6291 5912 5538 5166 4798 4431 19375 7869 7463 7065 6674 6289 591 5536 5165 4797 443 19125 7868 7462 7063 6673 6288 591 5535 5165 4797 443 18875 7868 7462 7063 6673 6288 591 5535 5165 4796 443 18625 787 7463 7065 6674 6289 591 5536 5165 4797 443 18375 7873 7466 7067 6676 6291 5912 5537 5166 4797 443 18125 7878 747 7071 6679 6294 5914 5539 5167 4798 4431 17875 7884 7476 7076 6684 6298 5917 5542 5169 4799 4431 17625 7893 7483 7083 6689 6303 5921 5545 5172 4801 4432 17375 7903 7492 7091 6696 6309 5926 5549 5175 4803 4433 17125 7914 7503 71 6704 6316 5932 5553 5178 4806 4435 16875 7928 7515 7111 6714 6324 5939 5559 5182 4809 4436 16625 7943 7529 7123 6725 6333 5947 5565 5187 4812 4438 16375 796 7544 7137 6737 6343 5955 5572 5192 4815 444 16125 7979 7561 7152 675 6355 5965 558 5198 4819 4442
118
15875 8001 7581 7169 6765 6368 5976 5589 5205 4824 4445 15625 8024 7601 7188 6781 6382 5987 5598 5212 4829 4447 15375 8049 7624 7208 6799 6397 6 5608 522 4834 445 15125 8077 7649 723 6819 6414 6014 562 5229 484 4453 14875 8107 7676 7254 684 6432 603 5632 5238 4847 4457 14625 8139 7705 728 6862 6451 6046 5645 5248 4854 4461 14375 8174 7737 7308 6887 6472 6064 566 5259 4861 4465 14125 8211 777 7338 6913 6495 6083 5675 5271 4869 4469 13875 8251 7806 737 6941 6519 6103 5691 5283 4878 4474 13625 8294 7845 7405 6972 6545 6125 5709 5297 4887 4479 13375 834 7886 7441 7004 6573 6148 5728 5311 4897 4484 13125 8388 793 748 7038 6603 6173 5748 5326 4907 449 12875 844 7977 7522 7075 6634 62 5769 5343 4918 4496 12625 8495 8026 7566 7114 6668 6228 5792 536 493 4502 12375 8553 8079 7613 7155 6703 6258 5816 5378 4943 4509 12125 8615 8135 7663 7199 6741 6289 5842 5398 4956 4517 11875 868 8194 7716 7245 6781 6323 5869 5418 4971 4524 11625 8749 8256 7771 7294 6823 6358 5898 544 4986 4532 11375 8822 8322 783 7346 6868 6396 5928 5463 5002 4541 11125 8899 8392 7892 7401 6915 6435 596 5488 5018 455 10875 898 8465 7958 7458 6965 6477 5994 5514 5036 456 10625 9066 8542 8027 7519 7018 6521 6029 5541 5055 457 10375 9155 8624 81 7583 7073 6568 6067 557 5075 4581 10125 925 8709 8177 7651 7131 6617 6107 56 5095 4592 9875 9349 8799 8257 7722 7193 6669 6149 5632 5117 4604 9625 9454 8894 8342 7797 7257 6723 6193 5665 514 4617 9375 9564 8994 8431 7875 7325 678 6239 5701 5165 463 9125 9679 9098 8525 7958 7397 684 6288 5738 519 4644 8875 98 9208 8624 8045 7472 6904 6339 5777 5217 4659 8625 9927 9324 8727 8137 7551 6971 6393 5819 5246 4674 8375 1006 9445 8836 8233 7635 7041 645 5862 5276 4691 8125 102 9572 895 8334 7722 7115 651 5908 5307 4708 7875 1035 9706 907 844 7814 7192 6573 5956 5341 4726 7625 105 9846 9197 8552 7911 7274 664 6007 5376 4745 7375 1066 9994 933 867 8014 7361 671 6061 5413 4766 7125 1083 1015 947 8794 8121 7452 6784 6118 5452 4787 6875 1101 1031 9617 8925 8235 7548 6862 6178 5494 481 6625 112 1049 9773 9063 8356 765 6945 6241 5537 4834 6375 114 1067 9937 9209 8483 7757 7033 6308 5584 4859 6125 1161 1086 1011 9364 8618 7872 7126 638 5634 4887 5875 1183 1106 103 9528 8761 7993 7225 6456 5686 4916 5625 1207 1128 1049 9703 8914 8123 7331 6537 5743 4947 5375 1231 1151 107 9889 9076 8261 7443 6624 5803 498 5125 1258 1175 1092 1009 925 8409 7564 6717 5867 5015 4875 1286 1201 1116 103 9436 8567 7694 6816 5936 5053 4625 1316 1229 1142 1053 9637 8738 7833 6924 601 5094 4375 1349 1259 1169 1078 9853 8922 7983 7039 609 5138 4125 1384 1292 1199 1104 1009 912 8146 7164 6177 5186 3875 1422 1327 1231 1133 1034 9336 8321 7299 627 5237 3625 1463 1365 1266 1165 1062 957 8512 7445 637 5291 3375 1508 1407 1304 1199 1092 9824 8719 7603 6479 middot535 3125 1557 1453 1346 1237 1124 101 8943 7773 6595 5412 2875 1612 1504 1393 1278 116 104 9185 7956 6719 5478 2625 1673 1561 1444 1323 1199 1073 9446 8152 6851 5546 2375 1741 1624 1501 1373 1242 1108 9725 8359 6989 5617 2125 1818 1695 1565 1429 1289 1146 1002 8575 713 5687 1875 1906 1775 1636 149 1339 1186 1032 8792 727 5755 1625 2007 1868 1716 1556 1392 1227 1062 9001 7401 5818
119
1375 1125 875 625 375 125
2127 2271 2449 2679 2994 3436
1975 2103 226
2467 2776 3361
1807 1912 2032 2173 2333 2469
1629 1707 1788 1863 191
1868
1447 1501 1548 1575 1559 1454
1266 1301 1324 1324 1279 1163
109 1111 112
1107 1058 9548
9183 9311 934
9205 8813 8043
7514 7591 7611 7544 735
6956
5873 5918 5953 5988 6049 6199
F6 Freezer Wall Simulation Output Including Anti-sweat Condenser Tube
INPUT PARAMETERS
Section Dimensions (mm) Width Length Depth Steel skin thickness Plastic skin thickness
5600 2000 1580 6500 2500
Mesh Geometry dx dy Number nodes in x-direction Number nodes in y-direction Number of steel skin nodes (including corner 00) Steel nodes under the seal Tube located at node
2800 2500 20 80
11 2 to 10 6
Steel skin conductivity (Wm K)
Foam insulation conductivity (Wm K) Plastic skin conductivity (Wm K)
Outside h (Wm2 K) Inside h (Wm2 K) Outside Temp (C) Inside Temp (C)
5400 27000E-02 1500 6870 6410 2100 -1000
OUPUT PARAMETERS
Number of iterations 879
ID Heat Flux Thru Wall (Wm2) 1362
Heat Transfer Along Metal Skin Under Seal node to node qm[Wm2] Qm[W]
2 3 -15024E+04 -1543 3 4 -15111E+04 -1552 4 5 -15205E+04 -1562 5 6 -15310E+04 -1572 6 7 5828 5986 7 8 5690 5844 8 9 5535 5684 9 10 5348 5492
Maximum difference (Is) 1356
j qleft[W] qright[W] -1 -1566 5928
120
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63
0 -62085E-02 -31363E-02 -5 9522E-02 -40097E-02 -44286E-02 -30955E-02 -33621E-02 -21814E-02 -25242E-02 -1 4577E-02 -1 8767E-02 -9 6252E-03 -13815E-02 -58162E-03 -10387E-02 -31499E-03 -73398E-03 -1 6265E-03 -54353E-03 -10285E-04
-35309E-03 27805E-04 -23882E-03 65891E-04 -16265E-03 14208E-03 -1 24 55E-03 14207E-03 -48371E-04 14207E-03 -10285E-04 10398E-03 -10285E-04 10399E-03 -10281E-04 10398E-03 -48371E-04 65891E-04 -1 02 85E-04 27805E-04 -86465E-04 16377E-04 -48375E-04 -52182E-04 -86465E-04 -97886E-04 -1 2455E-03 -13979E-03 -1 7788E-03 -16645E-03 -19692E-03 -21597E-03 -24263E-03 -25786E-03 -30357E-03 -30357E-03 -33404E-03 -35309E-03 -3 7975E-03 -3 9879E-03 -41784E-03 -44450E-03 -45974E-03 -49402E-03 -50164E-03 -53592E-03 -54353E-03 -58162E-03 -58543E-03 -62733E-03 -62733E-03 -66923E-03 -66542E-03 -71493E-03 -70351E-03 -75303E-03 -74541E-03 -7 9111E-03 -77969E-03 -83301E-03 -81397E-03 -87491E-03 -85206E-03 -90919E-03 -88634E-03 -94728E-03 -92062E-03 -97775E-03 -95109E-03 -10158E-02 -98537E-03 -10463E-02 -1 0158E-02 -10768E-02 -1 04 63E-02 -11073E-02 -10692E-02 -11377E-02 -10996E-02 -11644E-02 -11225E-02 -1 1949E-02 -11492E-02 -12215E-02 -11758E-02 -12444E-02 -11949E-02 -12672E-02 -12177E-02 -12901E-02 -12368E-02 -13129E-02 -12596E-02 -1 3282E-02 -12748E-02 -1 351 OE-02 -1 2977E-02 -13701E-02 -13129E-02 -1 3853E-02 -13282E-02 -14005E-02 -1 3434E-02 -14158E-02 -13586E-02 -14310E-02 -1 3701E-02 -14463E-02
121
64 -1 3815E-02 -1 4577E-02 65 -1 392 9E-02 -14691E-02 66 -14005E-02 -14767E-02 67 -14120E-02 -14881E-02 68 -14196E-02 -14958E-02 69 -1 4272E-02 -15034E-02 70 -14310E-02 -15110E-02 71 -1 4386E-02 -1 5148E-02 72 -14424E-02 -15186E-02 73 -14463E-02 -15224E-02 74 -14501E-02 -1 5262E-02 75 -14501E-02 -1 5300E-02 76 -14539E-02 -15262E-02 77 -14539E-02 -15300E-02 78 -1 4539E-02 -15262E-02 79 -14501E-02 -1 5300E-02
Qleft [Wj -1653 Qright [Wj 5163 Percent entering cabinet 2380
Freezer Nodal Temperatures (Condenser Tube)
x(mm) y(mm) 14 42 70 98 126 154 182 210 238 266
19875 9606 8457 7334 6235 516 4107 3075 2064 107 00944 19625 9596 8448 7325 6227 5152 4099 3068 2056 1064 00882 19375 9591 8443 732 6222 5148 4095 3064 2053 106 00850 19125 9591 8443 732 6222 5147 4095 3064 2052 106 00847 18875 9596 8448 7325 6226 5151 4099 3067 2056 1063 00873 18625 9606 8457 7334 6235 5159 4106 3074 2062 1069 00928 18375 9621 8472 7347 6248 5171 4118 3085 2072 1078 01013 18125 9641 8491 7366 6265 5188 4133 3099 2085 109 01128 17875 9666 8514 7388 6287 5208 4152 3117 2102 1106 01272 17625 9696 8543 7416 6313 5233 4176 3139 2123 1125 01447 17375 9731 8577 7448 6343 5262 4203 3165 2147 1147 01652 17125 9772 8616 7485 6378 5295 4234 3194 2174 1173 01888 16875 9817 8659 7526 6418 5333 427 3228 2206 1202 02156 16625 9868 8708 7573 6462 5375 431 3265 224 1234 02455 16375 9924 8762 7624 6511 5421 4353 3306 2279 127 02786 16125 9985 8821 7681 6565 5472 4402 3352 2322 131 03149 15875 1005 8885 7742 6624 5528 4454 3401 2368 1353 03546 15625 1012 8954 7809 6687 5588 4511 3455 2418 1399 03976 15375 102 9029 7881 6755 5653 4573 3513 2472 145 04441 15125 1029 911 7958 6829 5723 4639 3575 253 1504 0494 14875 1038 9196 804 6907 5798 4709 3641 2592 1562 05474 14625 1047 9287 8128 6991 5877 4784 3712 2659 1623 06045 14375 1057 9385 8221 708 5962 4865 3787 2729 1689 06652 14125 1068 9488 832 7175 6052 495 3868 2804 1759 07297 13875 1079 9597 8424 7275 6147 504 3952 2884 1833 07981 13625 1091 9713 8535 738 6247 5135 4042 2968 1911 08704 13375 1104 9834 8651 7491 6353 5235 4136 3056 1993 09466 13125 1117 9962 8774 7608 6464 534 4236 315 208 1027 12875 1131 101 8902 7731 6581 5451 434 3248 2172 1112 12625 1146 1024 9037 786 6704 5568 445 3351 2268 1201 12375 1161 1038 9178 7995 6833 569 4566 3459 2369 1294
122
12125 1177 1054 9326 8136 6967 5818 4686 3572 2475 1392 11875 1194 107 9481 8284 7108 5951 4813 3691 2585 1494 11625 1211 1087 9642 8439 7256 6091 4945 3815 2701 1602 11375 1229 1104 981 86 7409 6237 5083 3945 2822 1714 11125 1248 1122 9985 8768 757 639 5227 4081 2949 1832 10875 1268 1141 1017 8943 7737 6549 5378 4222 3082 1954 10625 1288 1161 1036 9125 7911 6714 5534 437 322 2083 10375 1309 1181 1055 9314 8092 6887 5698 4524 3364 2217 10125 1331 1203 1076 9511 8281 7067 5868 4685 3514 2356 9875 1354 1225 1097 9716 8477 7254 6046 4852 3671 2502 9625 1378 1248 1119 9929 8681 7448 6231 5026 3835 2654 9375 1402 1271 1142 1015 8893 7651 6423 5208 4005 2813 9125 1428 1296 1166 1038 9113 7861 6623 5398 4183 2979 8875 1454 1321 1191 1062 9342 808 6832 5595 4369 3152 8625 1481 1348 1216 1086 9579 8308 7049 5801 4562 3333 8375 1509 1375 1243 1112 9826 8545 7275 6015 4764 3522 8125 1538 1403 127 1139 1008 8791 751 6238 4975 3719 7875 1568 1432 1299 1166 1035 9047 7755 6472 5196 3925 7625 1598 1462 1328 1195 1063 9314 8011 6715 5426 4142 7375 163 1494 1358 1224 1091 9591 8278 697 5667 4368 7125 1663 1526 139 1255 1121 9881 8556 7236 5919 4606 6875 1697 1559 1422 1287 1152 1018 8847 7514 6184 4855 6625 1731 1593 1456 132 1185 105 9151 7806 6462 5118 6375 1767 1629 1491 1355 1218 1083 9469 8113 6755 5394 6125 1804 1665 1527 139 1254 1117 9804 8435 7063 5686 5875 1842 1703 1565 1428 129 1153 1015 8774 7388 5995 5625 1881 1742 1604 1466 1329 1191 1052 9133 7732 6322 5375 1921 1782 1644 1507 1369 1231 1091 9511 8097 6669 5125 1962 1824 1686 1549 1411 1272 1133 9913 8485 7039 4875 2004 1867 173 1593 1455 1317 1176 1034 8899 7435 4625 2047 1912 1776 164 1502 1363 1223 108 9341 7859 4375 2092 1958 1823 1688 1552 1413 1272 1128 9816 8315 4125 2138 2005 1873 1739 1604 1466 1325 1181 1033 8807 3875 2184 2055 1925 1793 166 1523 1382 1238 1088 934 3625 2232 2106 1979 1851 1719 1584 1444 1299 1148 992 3375 2282 216 2037 1911 1783 1649 1511 1366 1214 1055 3125 2332 2215 2097 1976 1851 1721 1584 1439 1286 1125 2875 2384 2273 2161 2045 1925 1798 1663 152 1366 1202 2625 2436 2334 2229 212 2005 1883 1751 1609 1455 1288 2375 249 2397 2301 22 2093 1976 1849 1708 1554 1384 2125 2546 2463 2377 2287 2188 2079 1957 182 1666 1493 1875 2602 2532 2459 238 2293 2193 2079 1946 1793 16 17 1625 266 2605 2546 2482 2407 232 2215 2089 1939 176 1375 2719 2681 264 2592 2533 2461 2369 2253 2108 1928 1125 2779 2761 2739 271 2671 2618 2543 244 2305 2128 875 2841 2844 2844 2838 2822 2792 2739 2655 2535 2367 625 2903 293 2954 2974 2986 2984 2959 2899 2802 2658 375 2967 3018 3069 3117 316 3194 3209 3173 3108 3009 125 3032 3108 3186 3263 3342 3421 35 347 344 3412
x (nun) y (nun) 294 322 350 378 406 434 462 490 518 546
19875 -0865 -1811 -2743 -3663 -4573 -5474 -6368 -7257 -8141 -9022 19625 -0871 -1816 -2747 -3667 -4577 -5477 -6371 -7259 -8142 -9024 19375 -0874 -1819 -275 -3669 -4578 -5479 -6372 -726 -8143 -9024 19125 -0874 -1819 -275 -367 -4579 -5479 -6372 -726 -8144 -9025 18875 -0872 -1817 -2748 -3668 -4577 -5478 -6372 -7259 -8143 -9025
123
18625 -0867 -1812 -2744 -3664 -4574 -5476 -637 -7258 -8142 -9024 18375 -0859 -1805 -2738 -3659 -457 -5472 -6366 -7256 -8141 -9023 18125 -0848 -1796 -273 -3652 -4563 -5466 -6362 -7252 -8139 -9022 17875 -0835 -1784 -2719 -3642 -4555 -546 -6357 -7248 -8136 -9021 17625 -0819 -1769 -2706 -3631 -4546 -5451 -635 -7243 -8132 -9019 17375 -0800 -1752 -2691 -3618 -4534 -5442 -6342 -7237 -8128 -9017 17125 -0779 -1733 -2673 -3602 -4521 -5431 -6334 -7231 -8124 -9014 16875 -0754 -1711 -2654 -3585 -4506 -5418 -6323 -7223 -8119 -9012 16625 -0727 -1686 -2632 -3565 -4489 -5404 -6312 -7214 -8113 -9009 16375 -0697 -1659 -2607 -3544 -447 -5389 -6299 -7205 -8106 -9005 16125 -0664 -1629 -258 -352 -445 -5371 -6286 -7194 -8099 -9001 15875 -0627 -1596 -2551 -3494 -4428 -5353 -6271 -7183 -8091 -8997 15625 -0588 -156 -2519 -3466 -4404 -5332 -6254 -717 -8083 -8993 15375 -0545 -1522 -2484 -3436 -4377 -531 -6236 -7157 -8074 -8988 15125 -0500 -148 -2447 -3403 -4349 -5287 -6217 -7143 -8064 -8983 14875 -0451 -1436 -2408 -3368 -4319 -5261 -6197 -7127 -8053 -8977 14625 -0399 -1388 -2365 -3331 -4287 -5234 -6175 -7111 -8042 -8971 14375 -0343 -1338 -232 -3291 -4253 -5206 -6152 -7093 -803 -8965 14125 -0284 -1284 -2272 -3249 -4216 -5175 -6127 -7074 -8017 -8958 13875 -0221 -1228 -2221 -3204 -4177 -5143 -6101 -7054 -8004 -8951 13625 -0155 -1168 -2168 -3157 -4137 -5108 -6073 -7033 -7989 -8943 13375 -0085 -1104 -2111 -3107 -4093 -5072 -6044 -7011 -7974 -8935 13125 -0011 -1037 -2051 -3054 -4048 -5034 -6013 -6987 -7958 -8927 12875 0065 -0966 -1988 -2998 -4 -4993 -598 -6963 -7941 -8918 12625 01474 -0892 -1922 -294 -3949 -4951 -5946 -6937 -7924 -8909 12375 0233 -0815 -1852 -2878 -3896 -4906 -591 -6909 -7905 -8899 12125 03229 -0733 -1779 -2814 -384 -4859 -5872 -688 -7885 -8888 11875 0417 -0648 -1702 -2746 -3782 -481 -5832 -685 -7865 -8877 11625 05157 -0558 -1622 -2675 -372 -4758 -5791 -6819 -7843 -8866 11375 06189 -0464 -1537 -2601 -3656 -4704 -5747 -6785 -7821 -8854 11125 07269 -0366 -1449 -2523 -3589 -4648 -5701 -675 -7797 -8841 10875 08398 -0263 -1357 -2441 -3518 -4588 -5653 -6714 -7772 -8828 10625 09577 -0156 -126 -2356 -3444 -4526 -5603 -6676 -7746 -8814 10375 1081 -0044 -116 -2267 -3367 -4461 -555 -6636 -7718 -88 10125 121 00732 -1054 -2174 -3286 -4393 -5495 -6594 -769 -8785 9875 1344 01957 -0943 -2076 -3202 -4322 -5437 -655 -766 -8769 9625 1484 03238 -0828 -1974 -3113 -4247 -5377 -6504 -7628 -8752 9375 1631 04575 -0708 -1867 -302 -4169 -5314 -6456 -7596 -8734 9125 1784 05974 -0582 -1755 -2923 -4087 -5247 -6405 -7561 -8716 8875 1944 07436 -0450 -1638 -2822 -4001 -5178 -6352 -7525 -8697 8625 2111 08966 -0312 -1516 -2715 -3911 -5105 -6296 -7487 -8676 8375 2286 1057 -0167 -1387 -2604 -3817 -5028 -6238 -7447 -8655 8125 2469 1224 -0015 -1253 -2486 -3718 -4948 -6177 -7405 -8633 7875 2661 14 0143 -1111 -2363 -3614 -4863 -6112 -736 -8609 7625 2861 1584 031 -0962 -2234 -3504 -4774 -6044 -7314 -8584 7375 3072 1778 04856 -0806 -2097 -3389 -468 -5972 -7265 -8558 7125 3293 1982 06704 -0641 -1954 -3267 -4581 -5896 -7213 -853 6875 3526 2196 08652 -0467 -1802 -3138 -4476 -5816 -7158 -8501 6625 3771 2422 1071 -0283 -1641 -3002 -4366 -5732 -71 -847 6375 403 2661 1288 -0089 -1471 -2858 -4248 -5642 -7038 -8437 6125 4303 2914 1519 01168 -1291 -2705 -4124 -5547 -6973 -8402 5875 4593 3182 1763 03357 -11 -2542 -3991 -5445 -6904 -8365 5625 49 3467 2023 05686 -0896 -2369 -385 -5338 -683 -8326 5375 5227 3771 23 08169 -0678 -2185 -37 -5223 -6751 -8284 5125 5576 4095 2596 1082 -0446 -1988 -354 -5101 -6668 -8239 4875 5949 4442 2913 1366 -0198 -1778 -337 -4971 -6579 -8193 4625 635 4814 3254 167 00669 -1553 -3187 -4832 -6485 -8143 4375 6781 5215 3619 1997 03519 -1313 -2993 -4685 -6385 -809
124
4125 7246 5647 4014 2349 06577 -1055 -2785 -4528 -6279 -8036 3875 775 6116 444 2728 0986 -0780 -2565 -4362 -6168 -7978 3625 8299 6625 4902 3137 1339 -0486 -233 -4187 -6051 -7919 3375 8899 718 5404 3579 1717 -0173 -2082 -4003 -593 -7859 3125 9558 7787 595 4057 2122 01586 -1823 -3813 -5806 -7798 2875 1028 8455 6545 4573 2555 0508 -1553 -3618 -568 -7739 2625 1109 9192 7197 513 3014 0872 -1277 -3422 -5558 -7683 2375 12 1001 7912 5729 3497 1245 -1002 -3233 -5442 -7633 2125 1301 1093 8698 6373 3998 1618 -0739 -3059 -534 -7592 1875 1418 1196 9566 7058 4508 1975 -0503 -2914 -5262 -7564 1625 1552 1314 1053 778 5007 2292 -0319 -2818 -5218 -7554 1375 171 1452 116 8525 5462 2528 -0224 -2798 -5226 -7564 1125 19 1616 1281 9263 5815 2621 -0272 -2892 -5304 -7597 875 2136 182 1417 9928 5968 2477 -0537 -3151 -5478 -7651 625 244 2095 1569 1037 575 1953 -112 -3637 -5773 -7713 375 2845 2514 1726 1027 4873 0854 -2146 -4427 -6224 -7757 125 3384 3296 1814 8879 2904 -1057 -3745 -5602 -6885 -7725
F bull 7 Seal Simulation Source Code and Ouput
Program Seal
c This program simulates the heat transfer characteristics of an c idealized refrigerator door gasket The steady-state temperature c profile is determined numerically from a 2-D finite difference c code
cxxxxxxxxxxxxx Parameters and Variablesxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
integer NNNWnsurfijjlloopiters real emmissigmakhihoTiTodelsNN real depthareatolkair
parameter (N=6) parameter (NN=20) parameter (W=7) parameter (nsurf=4N-l) parameter (emmis=09) parameter (sigma=567e-8) parameter (k=03) parameter (kair=0026) parameter (hi=641) parameter (ho=687) parameter (Ti=1032) parameter (To=209) parameter (sNN=02) parameter (del=sNNNN) parameter (depth=10) parameter (area=deldepth) parameter (tol=10)
real x(Onsurf)y(Onsurf)len(ONOnsurf) real F(OnsurfOnsurf) real T(-lNN+lONN)radl(nsurf+l)rad(Onsurf) real Eb(Onsurf)bvector(nsurf+l)Amatrix(nsurf+lnsurf+l) real difasumqsumqtotqin(NN-l) real rlr2r3r4r5
125
real clc2c3c4c5c6c7
open (lfilemiddotGasketoutposition-rewind) open (2file=Gasket(q)outpositionmiddotrewind)
cxxxxxxxxxxxxx Determine Viewfactors xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
call Points(Ndelnsurfxy) call length(Ndelnsurfxylen) call Vfactor(NdelnsurflenF)
cxxxxxxxxxxxxx Resistors (C-m2W)
c Interior x- and y-directions rl=delk
c Exterior to outdoor ambient r2=1ho
c Exterior to indoor ambient r3-1hi
c Radiation r4=(1-emmis)emmis
c Air r5=delkair
xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
cxxxxxxxxxxxxx Guass-Siedel Iteration xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
c Begin massive loop to determine the steady-state temperature c distribution across the section First update the interior nodes c by considering the radiative heat transfer among the interior c surfaces The radiative transfer is updated by calling a routine c which computes the new radiosities every iteration Loop until c tolerance is met
c Initialize temperature field do 10 i=ONN
do 11 jONN T(ij)=50
11 continue 10 continue
do 15 j=ONN T(-1j)=250 T(NN+lj)=50
15 continue
c Set temperatures for row y=O and row y=NN do 20 i=ONN
T(iO)=fl(idel) T(iNN)=f2(idel)
20 continue
cxxxxxxxxxxxxx Begin Iteration xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
loop=l iters=l do while (loop eq 1)
c Update radiosities using new temps and update interior surface nodes
call Jsolver(FemmissigmaTNNNWnsurfradlradEb + bvectorAmatrix)
c interior corners cl=area (2rl) c2=arearl
126
c3=area (2rl) c4=arearl c5=arear4 c6=1(cl+c2+c3+c4)
T(WW)=c6(clT(W+lW)+c2T(W-lW)+c3T(WW+l)+ + c4T(WW-l)+c5(rad(0)-Eb(0raquo)
cl=arearl c2=area(2rl) c3=area(2rl) c4=arearl c5=arear4 c6-1(cl+c2+c3+c4) T(W+NW)=c6(clT(W+N+lW)+c2T(W+N-lW)+c3T(W+NW+l)+
+ c4T(W+NW-l)+c5(rad(N)-Eb(Nraquo) clarearl c2-area (2rl) c3-arearl c4=area(2rl) c5=arear4 c6=1(cl+c2+c3+c4) T(W+NW+N)=c6 (clT(W+N+lW+N)+c2T(W+N-lW+N) +c3T(W+NW+N+l)+
+ c4T(W+NW+N-l)+c5(rad(2N)-Eb(2Nraquo) cl=area(2rl) c2=arearl c3=arearl c4=area(2rl) c5=arear4 c6=1(cl+c2+c3+c4) T(WW+N)=c6 (clT(W+lW+N) +c2T(W-lW+N)+c3T(WW+N+l) +
+ c4T(WW+N-l)+c5(rad(3N)-Eb(3Nraquo)
c Interior surface y=W jl=l do 22 i=W+lW+N-l
cl=area(2rl) c2=area (2rl) c4=arearl c5=arear4 c7=arear5 c6=1(cl+c2+c4+c7) T(iW)=c6(clT(i+lW)+c2T(i-lW)+
+ c7T(iW+l)+c4T(iW-l)+c5(rad(jl)-Eb(jlraquo) jl=j1+1
22 continue
c Interior surface y=N+W jl=3N-l do 25 i=W+lW+N-l
cl=area(2rl) c2=area (2rl) c3=arearl c5=arear4 c7=arear5 c6=1(cl+c2+c3+c7) T(iW+N)=c6(clT(i+lW+N)+c2T(i-lW+N)+
+ c7T(iW+N-l)+c3T(iW+N+l)+c5(rad(jl)-Eb(jlraquo) jl=jl-l
25 continue
c interior surface x=W jl=4N-l do 30 j=W+lW+N-l
c2=arearl
127
c3=area (2rl) c4=area(2rl) c5-arear4 c7-arear5 c6-1(c2+c3+c4+c7) T(Wj)-c6(c7T(W+lj)+c2T(W-lj)+c3T(Wj+l)+
+ c4T(Wj-l)+c5(rad(jl)-Eb(jl))) jl=jl-l
30 continue
c interior surface x=W+N jl=N+l do 35 j-W+lW+N-l
cl=arearl c3=area(2rl) c4=area (2rl) c5-arear4 c7-arear5 c6-1(cl+c3+c4+c7) T(W+Nj)=c6(clT(W+N+lj)+c7T(W+N-lj)+c3T(W+Nj+l)+
+ c4T(W+Nj-l)+c5(rad(jl)-Eb(jl))) jl=j1+1
35 continue
c Interior air nodes do 37 j=W+lN+W-l
do 38 i=W+lN+W-l call sseqn(Tr5r5r5r5areaareaareaareaijNN)
38 continue 37 continue
c Solid nodes do 40 i=lNN-l
do 45 jlW-l call sseqn(TrlrlrlrlareaareaareaareaijNN)
45 continue do 50 j=W+N+lNN-l
call sseqn(TrlrlrlrlareaareaareaareaijNN) 50 continue 40 continue
do 55 j=WW+N do 60 i=lW-l
call sseqn(TrlrlrlrlareaareaareaareaijNN) 60 continue
do 65 i=W+N+lNN-l call sseqn(TrlrlrlrlareaareaareaareaijNN)
65 continue 55 continue
c Side boundaries do 70 j=lNN-l
call sseqn(Trlr2rlrlareaareaarea2area20jNN) call sseqn(Tr3rlrlrlareaareaarea2area2NNjNN)
70 continue
c Apply energy balance around the boundary of the gasket to determine c stopping criterium dif
dif-OO dif=dif+(area(2rl))(T(00)-T(01)) dif=dif+(area(2rl))(T(0NN)-T(0NN-l)) do 90 i=lNN-l
dif=dif+(arearl)(T(iO)-T(il)) dif=dif+(arearl)(T(iNN)-T(iNN-l))
128
90 continue dif=dif+(area(2r1raquo(T(NN0)-T(NN1raquo dif=dif+(area(2r1raquo(T(NNNN)-T(NNNN-1raquo
do 95 j=1NN-1 dif=dif+(arear2)(To-T(0jraquo dif-dif+(arear3)(Ti-T(NNjraquo
95 continue
print dif
c Stopping criterium if (dif It toll then
loop-O endif if (iters eq 10000) then
loop=O endif
iters=iters+1 end do
cxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx c Compute heat flux into the cabinet
qsum=OO asum=OO do 97 j=1NN-1
qin(j)=hiarea(T(NNj)-Ti) qsum=qsum+qin(j) asum=asum+area
97 continue qtot=qsumasum write(2) heat flux to interior [Wm2)qtot
do 100 j=NNO-l write(l) (T(ij)i=ONN)
100 continue
pause stop end
c----------------------------------------------------------------------shyc------~----------------------------------------------------------------
Subroutine Points(Ndelnsurfxy)
integer Nnsurfi real delincrx(Onsurf)y(Onsurf)
x(O)=OO y(0)=del2
c Points along y=O edge incr-OO do 10 i=lN
y(i)=OO x(i)=(del2)+incr incr=incr+del
10 continue
c Points along x=Ndel edge incr=OO do 20 i=N+12N
x(i)=Ndel
129
y(i)-(del2)+incr incr-incr+del
20 continue
c Points along y=Ndel edge incr=OO do 30 i=3N2N+l-1
y(i)-Ndel x(i)=(del2)+incr incr-incr+del
30 continue
c Points along x-O edge incr=OO do 40 i-nsurf3n+l-1
xli) -00 y(i)-laquo3del)2)+incr incr-incr+del
40 continue
return end
c----------------------------------------------------------------------shyc-----------------------------------------------------------------------
Subroutine length(Ndelnsurfxylen)
integer Nnsurfij real dellen(ONOnsurf)x(Onsurf)y(Onsurf)
c Special case surface 0 do 10 j=Onsurf
len(0j)=sqrtlaquox(0)-x(jraquo2+(y(0)-y(jraquo2) 10 continue
c Surfaces along y=O do 20 i=IN-l
do 30 j=Onsurf len(ij)=sqrtlaquox(i)-x(jraquo2+(y(i)-y(jraquo2)
30 continue 20 continue
c Special case surface N do 50 j=Onsurf
len(Nj)=sqrtlaquox(N)-x(jraquo2+(y(N)-y(jraquo2) 50 continue
return end
c----------------------------------------------------------------------shyc-----------------------------------------------------------------------
Subroutine Vfactor(NdelnsurflenF)
integer Nnsurfijjlj2 real dellen(ONOnsurf)F(OnsurfOnsurf)Lzero
c Determine viewfactors for special case of surface 0 Lzero=delsqrt(20) do 10 j=Onsurf
if (j eq 0) then F(Oj)=OO
elseif (j eq nsurf) then F(Oj)=(len(Oj)+len(10)-len(00)-len(ljraquo(2Lzero)
else F(0j)=(len(0j)+len(lj+l)-len(Oj+l)-len(ljraquo(2Lzero)
130
endif 10 continue
c Determine viewfactors for surfaces on edge y-O
do 20 i=IN-l do 30 j=Onsurf
if (i eq j) then F(ij)=OO
elseif (j eq nsurf) then F(ij)=(len(ij)+len(i+l0)-len(i0)-len(i+ljraquo(2de1)
else F(ij)=(len(ij)+len(i+lj+l)-len(ij+l)-len(i+ljraquo(2del)
endif sum=sum+F(ij)
30 continue 20 continue
c Determine viewfactors for all other surfaces do 40 iON-l
do 50 j=03N-l F(i+Nj+N)=F(ij)
50 continue do 60 j=3Nnsurf
F(i+Nj-3N)=F(ij) 60 continue
do 70 j=02N-1 F(i+2Nj+2N)=F(ij)
70 continue do 80 j=2Nnsurf
F(i+2Nj-2N)=F(ij) 80 continue
do 90 j=ON-l F(i+3Nj+3N)=F(ij)
90 continue do 100 j=Nnsurf
F(i+3Nj-N)=F(ij) 100 continue
40 continue
return end
c----------------------------------------------------------------------shyc-----------------------------------------------------------------------
Subroutine Jsolver(FemmissigmaTNNNWnsurfradlradEb + bvectorAmatrix)
integer NNNnsurfij real emmissigmaF(OnsurfOnsurf) real T(-INN+10NN)rad1(nsurf+l)rad(0nsurf) real Eb(0nsurf)bvector(nsurf+1)Amatrix(nsurf+lnsurf+l)surn
c Compute Eb for all surfaces do 10 i-ON-l
Eb(i)=sigma(T(i+WW) 4) Eb(i+N)=sigma(T(W+Ni+W)4)
10 continue incr=W+N do 20 i=0N-1
Eb(i+2N)=siqrna(T(incrW+N) 4) Eb(i+3N)=sigma(T(Wincr)4) incr=incr-1
20 continue
131
c Assign values to vector b do 30 i=Onsurf
bvector(i+l)-(emmis(l-emmisraquoEb(i) 30 continue
c Assign values to matrix A do 40 i-Onsurf
do SO j=Onsurf Amatrix(i+lj+l)--F(ij)
SO continue 40 continue
c Override diagonal terms do 60 i-Onsurf
sum-OO do 70 j-Onsurf
sum-sum+F(ij) 70 continue
Amatrix(i+li+l)-(emmis(l-emmisraquo+sum 60 continue
c Call routine to solve the set of equations for unknown JS call gaussy(Amatrixbvectorradlnsurf+l)
do 80 i=Onsurf rad(i)=radl(i+l)
80 continue
return end
c----------------------------------------------------------------------shyc-----------------------------------------------------------------------
Subroutine Gaussy(abxn) c
integer nkiimaxjkplusllplus real a(nn)b(n)x(n)amaxbtempatemp
+ aeon sum
do 28 k=l n amax=OO do 4 i=kn if(abs(a(ikraquo-abs(amaxraquo442
2 amax=a(ik) imax=i
4 continue if(abs(amax)-0le-15)101014
10 printO equations are not independent return
14 btemp=b(k) b(k)=b(imax) b(imax)=btemp do 18 j=kn
atemp=a(k j) a(kj)=a(imaxj)
18 a(imaxj)=atemp kplus=k+l if(k-n)222828
22 do 24 i=kplusn b(i)=b(i)-b(k)a(ik)a(kk) acon=a(ik) do 24 j=kn
24 a(ij)=a(ij)-a(kj)acona(kk) 28 continue
132
l=n 32 sum=OO
if(1-n)343838 34 lplus-1+1
do 36 j-lplusn 36 sum=sum+a(lj)x(j) 38 continue
x(l)-(b(l)-sum)a(ll) if(1-1)424240
40 1-1-1 goto 32
42 return end
c----------------------------------------------------------------------shyc-----------------------------------------------------------------------
Subroutine sseqn(TriplusriminusrjplusrjminusAiplus + AiminusAjplusAjminusijNN)
c This subroutine computes the temperature at node (ij) c given the temperatures of the surrounding nodes and c the resistances leading to these nodes
integer ijNN real T(-1NN+10NN)riplusriminusrjplusrjminus real AiplusAiminusAjplusAjminus real c1c2c3c4c5
c1=Aiplusriplus c2=Aiminusriminus c3=Ajplusrjplus c4=Ajminusrjminus c5=1(c1+c2+c3+c4)
T(ij)=c5(c1T(i+1j)+c2T(i-1j)+c3T(ij+1)+c4T(ij-1raquo
return end
c----------------------------------------------------------------------shyc----------------------------------------------------------------------shy
real function f1(x) c door BC
real x f1-18520 - 23413x
return end
c----------------------------------------------------------------------shyc----------------------------------------------------------------------shy
real function f2(x) c wall BC
real x f2=18128 - 3475x
return end
c----------------------------------------------------------------------shyc----------------------------------------------------------------------shy
133
Fresh Food Compartment Simulations Results
Run 1 The prescribed temperature profiles are
Wall 19203 - 1908 x Door 19203 - 1206 x
(x is in meters)
Outdoor Ambient = 210 degC Local Indoor Ambient = 1533 degC
Run 2 The prescribed temperature profiles are
Wall 18989 - 2024 x Door 19078 - 1326 x
(x is in meters)
Outdoor Ambient = 210 degC Local Indoor Ambient = 1496 degC
Run 3 The prescribed temperature profiles are
Wall 1895 - 1998 x Door 19053 - 1384 x
(x is in meters)
Outdoor Ambient = 208 degC Local Indoor Ambient = 1491 degC
Ayem~ Values Wall 1905 - 1977 x Door 1913 - 1384 x
(x is in meters)
Ave Outdoor Ambient = 209 degC Ave Local Indoor Ambient =1507 degC
Loss from Fresh Food == 10 W
134
Freezer Compartment Simulations Results
Run 1 The prescribed temperature profiles are
Wall 1821 - 343 x Door 18606 - 2354 x
(x is in meters)
Outdoor Ambient = 210 degC Local Indoor Ambient = 1029 degC
Run 2 The prescribed temperature profiles are
Wall 18182 - 3542 x Door 18544 - 2398 x
(x is in meters)
Outdoor Ambient = 210 degC Local Indoor Ambient = 1042 degC
Run 3 The prescribed temperature profiles are
Wall 17993 - 3452 x Door 18411 - 2272 x
(x is in meters)
Outdoor Ambient = 208 degC Local Indoor Ambient = 1024 degC
Ayera~e Values Wall 18128 - 3475 x Door 18520 - 23413 x
(x is in meters)
Ave Outdoor Ambient = 209 degC Ave Local Indoor Ambient = 1032 degC
Loss from Fresh Food = 157 W
135
I
I I
I
I
I I I
I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I
I I I I I I I I I I I I I I I I I I I I I I
1 INTRODUCTION
New regulations recently announced by the Department ofEnergy call for substantial
energy efficiency increases for household appliances by 1993 The refrigerator is of
particular interest since it is the largest household consumer of electricity and accounts for a
large part of the 8 of the electricity used in the US for food-cooling both residential and
commercial In addition to efficiency standards regulations are being imposed on the use
of CFCs completely banning their use by the year 2000 (Braswell 1988)
The objective of this thesis is to present an analysis of all heat transfer paths from the
surroundings to the interior food compartments of the refrigerator under closed door
conditions Both experimental and numerical methods are used as a means to determine the
overall cabinet load as well as the load due to each pathway The study is focused on a
particular unit for practical purposes However the methods implemented may be applied
to any make or model to aid in the search for high efficiency cabinets
All loads determined in this study are strictly cabinet loads and not the loads seen by the
refrigerator system The thermal load on the cabinet is comprised of three main parts (i)
the load due to the one-dimensional heat transfer through the walls and doors to the food
compartments away froin the edges (ii) the load due to edge effects that is heat transfer
into the food storage compartments via paths around the perimeter of the cabinet aperture
and (iii) other miscellaneous sources
(11)
The determination of qlD is straightforward and is discussed in detail in Chapter 3 The
edge load must be broken down into several parts for examination
qedge = qwall + qdoor + qseal + qrnullon + qtubeave (12)
where
qwall heat input due to conduction along the wall steel flange
qdoo heat input due to conduction along the door steel flange
qseal heat conduction directly through the door seal
1
heat input due to conduction in the mullion region with the additional input from an anti-sweat heater
qtubeave heat input due to cabinet anti-sweat condenser tube averaged over the cycle time
heat input due to cabinet anti-sweat condenser tube
heat input due to conduction in the mullion region electric heater off
It is assumed that an electric anti-sweat heater in the mullion region is in use for the entire
cycle The test unit chosen for this study required this region to be heated almost
continually to eliminate condensation This load is represented by qmulloo in Eq (12)
The load qmulloff is due to heat conduction to the interior compartments at the mullion
region when the electric heater is off Although this value does not appear in the edge load
definition it is still important to detennine for sake of comparison with the value of
qmulloo The load due to the presence of an anti-sweat condenser loop around the aperture
of the cabinet is defmed as qtube Since this load is present for the on cycle only it must be
integrated over the cycle time to be included in Eq (12) hence the tenn qtubeave
The tenn qroisc is expressed as
qmisc = qfanave + qdefrostave + qcompave (13)
where
qfanave heat input from the evaporator fan averaged over the cycle time
qdefrostave heat input from the defrost heaters averaged over defrost cycle time
qcompave heat input from elevated exterior walls near the running compressor
Figure 11 is a cross sectional drawing of the door seal area of the test refrigerator
examined to detennine qwalI qdoor and~ The figure includes materials and their
properties taken from Incropera and Dewitt (1985)
2
400 ~I-I~ 065~
065 Only dimension that is different for the freezer
200
kltWIm-K)
Outer Steel Skin 540 312~ Polyurethane Wall Insulation 0027 0015- Inner Plastic Skin 015 009~
~ Rubber Gasket 03 017fm1I ~ ~ Glass Fiber Door Insulation 004 0023
All dimensions in millimeters
1 in= 254mm
Fig 11 Door Seal Region Cross Section
3
Figure 12 is a drawing of the mullion region cross section of the test refrigerator examined
to detennine ltlmullon and ltlmulloff
FREEZER
Freezer Gasket
Fresh Food Gasket
FRESH FOOD COMPARTMENT
Fig 12 Mullion Region Cross Section
The remainder of this thesis is devoted to the analysis of the closed door cabinet loads and
the experimental and numerical techniques used for their detennination
An experimental investigation of fumed silica as an alternative insulation for the refrigerator
is presented in Appendix A Although this appears to be a departure from the main topic
a relation exists The desire of higher efficiency requires a search for equal if not better
cabinet insulations that do not incorporate the use of ozone damaging CFCs Testing is
done to detennine the thennal conductivity and diffusivity of fumed silica for several
densities
4
2 LITERATURE REVIEW
The new energy standards imposed by the Department ofEnergy have sparked research in
the area of refrigerator efficiency and alternative refrigerants A study by Turiel and
Heydari (1988) focused on several ways to improve the efficiency of refrigerator-freezers
and freezers
Various classes for the study were chosen however the paper presents extensive results for
the most common variety a top-mounted automatic defrost refrigeratorfreezer The
design options considered were those changes that can be incorporated into the existing
refrigerator design Two types of improvements are noted (i) changes that increase energy
efficiency by decreasing the heat transfer into the cabinet and (ii) changes that increase the
efficiency by reducing auxiliary electricity use or improving the refrigeration system Type
(i) changes include Foam insulation substitution increased insulation thickness double
door gaskets improved foam insulation evacuated insulation panels and reduced heat load
of through-the-door feature Type (ii) changes include High efficiency compressor
substitution adaptive defrost fan and fan motor improvement anti-sweat heater switch
increased evaporator surface area hybrid evaporator enhanced heat transfer surfaces
mixed refrigerants improved expansion valve fluid control valve two-compressor system
use of natural convective currents and location of compressor condenser and evaporator
fan motor
Turiel and Heydari used a model developed by Little (1982) to carry out the energy use
simulations This model is a steady-state energy use simulation which computes the heat
leakage to the cabinet and then determines the energy needed to maintain the interior
ambient temperatures dictated by the OOE test procedure Turiel and Heydari present the
energy consumption figures for a 18 cubic foot top-mounted automatic defrost
refrigeratorfreezer as a baseline case They find that 74 of the total energy is accounted
for by the compressor 11 is for the anti-sweat heaters 10 is for the fans and 5 is
for the defrost heaters for a total of 947 kWhyr Also about 10 of the compressor
energy use is for the removal of internal heat generated by the evaporator fan motor defrost
heater and anti-sweat heaters
Several subsequent simulations were performed each time adding a design option that was
projected to improve efficiency The improvement levels were added cumulatively and
results were given on compressor run time heat leakage rate into the cabinet compressor
5
power demand at the operating point fan motor operating power for the evaporator and
condenser fans anti-sweat heater power and total daily and annual energy consumption
The goal here was to achieve by the last level of improvement the minimum energy
consumption that is technologically feasible One important fmding for all product classes
tested the highest efficiency was obtained by the use of evacuated panels in the planar
walls For example for the top-mounted automatic defrost unit the minimum energy use
was 515 kWyr
Finally an energy usevolume relation was developed from a linear regression obtained
from simulation results The resulting fit was shown as
Energy Use = Cl + C2Adjusted Volume
The constant Cl indicates the direct energy use to remove the cabinet loads associated with
the fan motors and heaters The slope C2 is an indicator of the rate of change ofenergy use
with a change in the adjusted volume This value reflects the rate of cabinet heat gain The
adjusted volume is the volume of the fresh food compartment plus 163 times the volume
of the freezer Turiel and Heydari produced a series of regressions for all of the defined
levels of design improvements allowing easy comparison at a specific adjusted volume
6
3 ONE-DIMENSIONAL WALL AND DOOR LOADS
In this section the overall steady cabinet load is calculated without considering the addition
of edge loading This load qlD is dermed as the heat transfer from the exterior
environment to the interior of the refrigerator under nonnal closed-door operating
conditions through four primary conductive paths (i) fresh food compartment walls (ii)
freezer walls (iii) fresh food door and (iv) freezer door In a later chapter the load due to
edge loading will be examined more closely
31 One-dimensional Heat Transfer Model
The steady conductive heat transfer through the walls of the refrigerator cabinet is
computed using a simple computer program written by Qausing (1983) This program
estimates inside and outside effective heat transfer coefficients using a flat plate natural
convection correlation Using these coefficients and the material properties and dimensions
of the wall insulation the one-dimensional heat transfer through the cabinet walls is
approximated for the fresh food and freezer compartments Figure 31 shows the
resistances and boundary conditions use in the model
Fig 31 Model Used To Calculate One-dimensional Load
7
The model provides flexibility for varying several parameters This allows application to
various types of refrigerator walls and doors Table 31 lists the input and output
parameters for the model The source code of the simulation along with the output for
completed runs are included in Appendix B
Table 31 One-dimensional Model Parameters
Input Parameters
To K (F) Room ambient temperature
Ti K (F) Interior ambient temperature
LiDs m (ft) WalVdoor insUlation thickness
kiDs Wm-K (Btuhr-ft-F) WalVdoor insulation thermal conductivity
A m2 (ft2) Cabinet surface area
Output
beo Wm2K (Btuhr-ft2_F) Exterior convective heat transfer coefficient
bei Wm2K (Btuhr-ft2-F) Interior convective heat transfer coefficient
hro Wm2K (Btuhr-ft2_F) Exterior effective radiative heat transfer coefficient
hri Wm2-K (Btuhr-ft2_F) Interior effective radiative heat transfer coefficient
qlD W (Btuhr) Heat transfer rate through specified section
32 Determination of Effective Heat Transfer Coefficients
The simulation developed automatically estimates the inside and outside effective heat
transfer coefficients This effective value is the sum of the convective and radiative
components which are defined below
The radiative heat transfer coefficients are computed iteratively using eqs (31) and (32)
assuming (i) gray walls at temperatures T wi or Two with emissivities poundi and Eo (ii) black
surroundings at Ti or To and (iii) walls can see surroundings only
(31)
(32)
8
The convective heat transfer coefficients are estimated from a flat plate natural convection
correlation developed by Clausing (1983) In the laminar regime (Ra lt 1()9) the Nusselt
number based on the film temperature is given by Eq (33)
NUf = 052 Ra4 (33)
For the turbulent regime (Ra ~ 109) the Nusselt number becomes
NUf = 009 Raf3 (34)
where in both cases
Tw+T_ Film temperature T f == 2
Lc == Vertical surface characteristic length g == Gravitational acceleration f3 == Thermal expansion coefficient v == Kinematic viscosity Tw == Vertical wall surface temperature T_ == Outsideinside ambient temperature
kf == Air thermal conductivity
The film temperature characteristic length Nusselt number and Rayleigh number will
have different values for the inside surface compared with the outside surface of the
cabinet Therefore the inside and outside convective heat transfer coefficients are
determined separately from eqs (35) and (36)
(35)
- NUfo kfohco - (36)Leo
9
33 Results
The four primary regions analyzed are (i) the fresh food compartment walls (ii) fresh food
door (iii) freezer walls and (iv) the freezer door The values for the input parameters
ltLins kins A) are taken from a full-size unit that is used for the experimental analysis
presented in Chapter 4 The room temperature is used for the model parameter To Also
the fresh food ambient Tee and the freezer ambient Tfz are substituted for Ti when
suitable in order to closely simulate real operating conditions The results are given in
Table 32
Table 32 Results From One-dimensional Load Analysis
Input
Section TooC eF)
Tj degC eF)
Lins m (ft)
kins Wm-K (Btuhr-ft-OF)
A m2 (fi2)
Fresh Food 21 4 0045 0027 242 Walls (698) (392) (0148) (0015) (2605)
Fresh Food 21 4 0040 0040 089 Door (698) (392) (0131) (0023) (958)
Freezer 21 -10 0056 0027 110 Walls (698) (-140) (0184) (0015) (1184)
Freezer 21 -10 0040 0040 034 Door (698) (-140) (0131) (0023) (366)
Output
Section hco Wm2-K cBtuhr-ft2-Fl
hro Wm2-K iJtuhr -ft2-Fgt
hci Wm2-K (Btuhr-ft2-F)
hri Wm2-K 1Btuhr-ft2-F)
qlD W (Btuhr)
Fresh Food 130 544 198 461 209 Walls (23) (96) (35) (81) (713)
Fresh Food 144 542 218 463 117 Door (25) (95) (38) (82) (399)
Freezer 143 542 226 397 143 Walls (25) (95) (39) (70) (488)
Freezer 164 538 259 400 81 Door (29) (94) (46) (70) (276)
herro =687 Wm2 K (121 Btulhr-ft2-OF) Total qlD =550 W herrrr = 670 Wm2 K (118 Btulhr-ft2_0F) (1876 Btuhr)
herrrz = 641 Wm2 K (113 Btulhr-ft2-OF)
The load for our operating conditions is 550 W (1876 Btuhr) Once again this quantity
does not reflect the total cabinet load on the refrigerator cabinet Edge effects are analyzed
in detail in the following chapters Another important result is the values for the effective
10
inside and outside heat transfer coefficients which are simply the sum of the convective
and radiative components The outside coefficient is heffo the fresh food coefficient is
heffff and the freezer coefficient is hefffz These numbers are used whenever film
coefficients are needed for computations
11
4 EXPERIMENT AL ANALYSIS
This section presents an experimental study performed on a full-size household
refrigerator In Chapter 3 we defined the load due to heat transfer through the walls and
doors of the cabinet as qlD The purpose of this experimental analysis is to quantify qwalh
qdoor qmulloff and Qrnullon and Qmisc Three types of tests are performed to accomplish
this task Descriptions of each are presented separately in the sections that follow
41 Temperature Profile Measurements
The refrigerator is instrumented with many thermocouples in various key areas to give
temperatures across the steel skin and to compare and verify the thermopile tests outlined
in the next section The four primary paths along the steel flange that are examined are the
wall-side fresh food door-side fresh food wall-side freezer and the door-side freezer
Five Type T 36 AWG thermocouples are placed along the skin for each path Figure 41
is a detailed drawing of the location of the thermocouples
Wall side TICs Door side TICs with 5 mm spacing with 5 mm spacing
Fig 41 Steel Skin Temperature Profile Thermocouple Placement
The wire leads are oriented so they run perpendicular to the temperature gradient so as to
reduce any effects of conduction along the wire to the bead The temperature data are fed to
the data acquisition system Each channel is a thermocouple input and is scanned at a rate
of 5 times a second The data are smoothed automatically by the software in blocks of 10
12
points for an average temperature every 2 seconds A full description of the data
acquisition and control system is provided in Appendix D
Data are collected for several runs to provide a good base to detennine average values since
the test conditions vary slightly from run to run To get a good measurement of the
temperature profIles along the steel flange the unit is shut off at the beginning of the run
and allowed to drift to quasi-steady conditions The presence of a large amount of thennal
mass (see Appendix C) within the refrigerator provides for a stable interior ambient
temperature during data collection The outer ambient is controlled by the room thennostat
which keeps the laboratory at a constant temperature to within plusmn1degC
Figure 42 is an example plot of a run that gives the temperature profIles along the steel
skin on the wall-side and door-side for the fresh food compartment
193
192
G 191 ~
i 19
middot5 189F
188
Run I iii --0 - Door Profile
~Imiddotmiddotmiddotmiddotmiddotmiddotmiddott 0 Wall Profue
i ~ i - - T =19273 - 001206x i i-- door i If ~
=-r~r==L~r=I ~ I +~~=~~~~~~~~~ middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot
Outdoor Ambient = 210 degC Fresh Food Ambient =48 degC
187-+----+----J------I----+---~
o 5 10 15 20 25
x (mm) 1 in= 254 mm
Fig 42 Steel Skin Temperature Plot for Fresh Food Compartment
The dashed line represents a linear least-squares fit for the door data and the solid line is the
corresponding fit for the cabinet wall data Each data point in the plot represents the
average temperature at that point over a period of time at quasi-steady conditions
Similarly Figure 43 is a plot of the temperature profIles for the freezer
13
186
184
a 182
~
i 18
5 178~
176
174
Run 1 t-- 1 1 --0 - Door Profde
P~P1 0 Wall Profile
- -LLl--=-+--shy- - Tdo = 18606 - O02354x i
or ~
=c==-rc1 1 ltb 1 ~
~~r--r- -r---shy0 5 10 15 20 25
x (mm) 1 in= 2S4mm
Fig 43 Steel Skin Temperature Plot for Freezer
A total of six separate runs were perfonned three for the fresh food compartment and three
for the freezer Plots for the other runs are located in Appendix E
From the figures above for the fresh food compartment the slope on the wall-side is
slightly steeper than the slope on the door-side In fact this trend is seen for all the runs
Therefore the heat conduction along the metal skin into the cabinet along the wall is
somewhat greater than that of the door For the freezer the slopes are nearly equal hence
the heat conduction along the wall skin and the door skin are nearly the same
42 Thermopile Testing
Another simple but important test is the use of a thennopile to measure the average
temperature difference at various locations on the steel flange regions of the unit Figure
44 is a schematic of the thennopile test set-up The thennopile is constructed from 36
AWG copperconstantan thennocouple wire
14
-
CopperConstan$t Junctions 285 mPt
IOmm
10mmThermopile
IOmm
Digital Multimeter
1 in= 254mm
Fig 44 Thermopile Test Apparatus
Five junctions are used for the fresh food compartment and three for the freezer The
junctions are mounted 10 mm (039 in) apart from one another along the steel skin beneath
the door seal Figure 45 is a detailed drawing of the lateral location of the thermopile
junctions
15
1 in =254 mm
Fig 45 Thermopile Placement
The thennopile provides an average temperature difference across the junctions The
output voltage must frrst be divided by the number of pairs of junctions and then translated
into a temperature difference using a referencing chart for the thennocouple wire Table
41 is a summary of the results from these tests The output voltages are read accurately to
within plusmn0002 mV The raw data and data reduction procedure are given in Appendix E
Table 41 Thermopile Output
Test Conditions Fresh Food aT Freezer aT TodegC
(OF) TffoC
(OF) Tfzoc
(OF) aTwallff degC
(Of) aTdoorffoc
(OFgt aTwallfzoC
(Of) aTdoorfzoC
(OFgt
1 210 (698)
48 (406)
-88 (162)
026 (047)
024 (043)
037 (067)
041 (074)
2 210 (698)
37 (387)
-87 (163)
027 (049)
026 (047)
038 (068)
040 (072)
3 208 (694)
37 (387)
-93 (153)
027 (049)
026 (047)
038 (068)
040 ( 072)
Average Values 209 (696)
40 (392)
-90 (158)
0267 (0481)
0253 (0455)
0377 (0679)
0403 (0725)
43 Thermocouple Drag Testing
One final technique applied is thennocouple drag testing This is a more qualitative method
to supply insight into what exactly is happening when the compressor is pumping wann
16
refrigerant through the anti-sweat tube that lines the perimeter of the cabinet aperture The
main objective of this test is not to give accurate temperature proftle infonnation but
instead to detennine the placement of the condenser tube This is needed as an input for
the numerical simulation of this region The reason that the temperature are not accurate is
the fact that the thermocouple is being dragged across a surface where good thermal contact
may not occur and significant energy may be generated Figure 46 is a schematic of the
apparatus used for drag testing
Power Supply
Data Acquisition System
Outer Metal Skin
Potentiometer
Inner Plastic Skin
Condenser Tube
Fig 46 Thermocouple Drag Test Apparatus
This device is quite simple yet very effective The type T 36 AWG thennocouple begins
at the interior boundary of the steel skin beneath the seal on the wall-side of the cabinet
The potentiometer is turned by hand moving the thennocouple oqtward along the skin
The temperature and location are stored simultaneously this way The thennocouple is kept
17
pressed against the steel flange by the seal The linear translation of the thennocouple is a
function of the output voltage Voutbull
s = 2mllT Vout (41)Yin
r =radius of potentiometer post =30 mm (012 in)
nT = total number of turns of potentiometer = 10
Vin = input voltage = 05 V
Vout = output voltage
Drag tests are run on the wall steel skin for both the fresh food compartment and the
freezer Runs are perfonned at four separate times the first being when the compressor
turns on Figure 47 is a plot of the drag proflles across the wall-side skin in the fresh food
compartment Figure 48 is a plot of the profiles in the freezer compartment The same
trends are generally seen for both regions The freezer profiles are simply shifted down in
temperature values as expected The temperature peak seems to move through time to
settle near the center of the flange region under the seal
31
30
29
G
i 28~
27
26~
25
24
23
e
Ji ~ i i i 1middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotlmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddoti~~
---l- Time 4
o Time 2 rr
i
0 5 10 15 20 x (mm)
Fig 47 Drag Profiles (Fresh Food)
18
26~--------+---------~-------4--------~
i ~
Time 1 24
22
20
18
16~~------+---------~-------4--------~
4 __
~~Time3
middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot_middotmiddot_middotmiddotimiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot
Outer Seal Edge o
o 5 10 15 20
x (mm)
Fig 48 Drag Profiles (Freezer)
44 Experimental Determination of qwall and qdoor
The results from the temperature profile and thennopile testing are used to detennine qwall
and qdoor according to the following defmitions
qwall = qwallff + qwallfz (42)
(43)
Where qwal1ff = heat conduction along wall-side fresh food compartment steel flange
qwallfz = heat conduction along wall-side freezer compartment steel flange
qdoorff = heat conduction along door-side fresh food compartment steel flange
qdoorfz = heat conduction along door-side freezer compartment steel flange
The trends derived from the fixed profiles exhibit generally good agreement with the
temperature differences seen by the thennopile For the fresh food compartment the
thennopile displays a slightly larger AT than what is seen in the profiles and both give a
19
slightly larger temperature difference for the wall-side compared with the door-side For
the freezer the temperature differences match closely on the wall-side however the doorshy
side AT is shown to be somewhat less than the wall-side AT for the fIXed thennocouple
measurements where the opposite is seen from the thennopile The worst discrepancy is
on the order of 10 and is probably due to the fact that the thennopile gives an average temperature difference at several vertical locations on the wall whereas the other method is
at one vertical location only
Since the thennopile produces an average temperature difference across the steel skin its
output is used to detennine the heat flux into the cabinet The refrigerator casing is being
used as a heat meter Thus the flux along the skin in the fresh food compartment on the
wall-side is
kmiddot ATwallffqwallff = m (44)
Ax
The load qwallJf is Eq (44) multiplied by the cross sectional area This area is the
thickness of the steel casing multiplied by the perimeter that is exposed to the room
ambient This perimeter varies for each of the two paths that comprise qwall and the two
paths that comprise qdoor The other cabinet loads are computed in a similar way and are
given in Table 42 The details of these values are given in Appendix E
Table 42 Experimental Determination of qwall and qdoor
Section Load W (BtuIhr)
qwallJf 28 (96)
qwallJz 21 (72)
qwall 49 (168)
qdoorff 33 (112)
qdoorJz 33
1112)
qdoor 66 (224)
20
45 Experimental Determination of qmulloff
The region that lies between the fresh food compartment and the freezer is called the
mullion The front portion of the mullion is covered by a thin steel face plate to provide a
suitable interface for the door seal magnets In this section the load due to heat conduction
along the mullion steel skin into the freezer and fresh food compartment is detennined
based on the experimental data
The heat transfer rate qmulloff is sum of two parts The first component is the heat
conduction along the steel plate into the fresh food compartment and the second is the
conduction into the freezer
qmulloff = qmulloffff + qmullofffz (45)
Figure 49 schematically illustrates paths of these two components
FREEZER
FRESH FOOD COMPARTMENT
Fig 49 Heat Flow Paths in Mullion
21
Ten 36 A WG type T thennocouples are mounted from top to bottom across the steel face
plate Figure 410 shows the cross section of the plate and the location and numbering of
the thennocouples
FREEZER
1bennocouplesSteel Face (5 mm spacing from
Plate bottom edge)
Freezer Gasket
Fresh Food Gasket
10 50
FRESH FOOD COMPARTMENT
1 in =254 mm
Fig 410 Mullion Face Plate Cross Section
Data are gathered from the ten thennocouples when the unit is shut off and allowed to drift
to a quasi-steady ambient temperature A total of five runs were perfonned Figure 411 is
a sample plot of the quasi-steady temperature profile All other plots are contained in
AppendixE
22
116
Run 1 I 115 ICcIIIII114 iii t ~mull~ =12~7 - 00~654xa
~ 113
rrfIIJ~~If112i 5 )mullfz 1= 1081~ + OOdl25X 111111 ~
11 oo+-t--t-iH-+-lo-shyiii i i Room Ambient = 2184 degc
109 middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1middot Fresh Ambient = 381 OC
108
1 10
I I I I I Freezer Ambient =-832 degc
2 3 4 5 6 7 8 9
TIC
Fig 411 Mullion Temperature Profile
The plot also shows two linear equations These represent linear fits to each side of the
peak temperature at TIC 7 The slopes (shown in degCmm) are used to detennine the heat
conduction to each compartment by eqs (46) and (47)
lmulloffff = km A (aT) (46)ax offff
qmul)offfz = km AIll) (47)ax offfz
The cross sectional area is the product of the face plate thickness (10 mm 0039 in) and
the length of the mullion (717 mm 2825 in) The average slopes from all five runs are
used to detennine qmulloffff and qroullofffz The results are given in Table 43
23
Table 43 Experimental Results from Mullion Analysis
Load W (Btuhr)
09qmullofUz (31)
07qmulloffff (24)
16qmuIlorr (55)
46 Experimental Determination of qmullon
In this section the load due to heat conduction along the mullion steel skin into the freezer
and fresh food compartment when an anti-sweat heater is on is experimentally determined
The test unit is equipped with an electric anti-sweat heater to eliminate condensation in the
mullion region The heater is installed on the back side of the plate and may be switched on
manually when needed It is a wire resistor type rated at 10 watts
The heat transfer rate qmullon is composed of two parts The first component is the heat
conduction along the steel plate into the fresh food compartment and the second is the
conduction into the freezer similar to ~ul1off
qmuIlon = ~ullonff + qmuIlonfz (48)
The location of the wire heater and the heat transfer paths are shown in Figure 412
24
FREEZER
qmullonfz
qmullonff
FRESH FOOD COMPARTMENT
Fig 412 Electric Heater Location
A series of tests are perfonned while the heater is on and the refrigerator is cycling
nonnally Three runs are done at each of three separate locations along the mullion
laterally (i) LEFT dermed as 180 mm (71 in) from the left-hand side of the unit (ii)
RIGHT 180 mm (71 in) from the right-hand side of the unit (iii) CENTER at center of
the mullion Figure 413 is a plot of the temperature profile across the face plate when the
heater is on for a specific test run The plots for all other runs are provided in Appendix E
The plot shows two profiles These represent the upper and lower limits as the unit cycles
The upper limit occurs just before the compressor turns on while the lower limit is at the
point in time just before the compressor shuts off At all times in between the profile
oscillates between the two limits maintaining nearly the same shape Once again a linear
fit is applied to the data on the fresh food side and the freezer side
25
30 iii imiddot iii i
29
28
27
Run 1
T mu
ill~~ 11 f = 26707 + 010776x Tmu11ff = 3128 - 00793x
Z +_ a 26~
I ~
middotmiddotmiddotbull-middotbullimiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotimiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotimiddotmiddotmiddotimiddotmiddot
24
25
e 23~ =H-T+H~i=i=
iimiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotimiddotmiddot T 11 ff = 27435 - 009504x 22 Tmullfz =21865 + 01l786x I m~ iii
21 -lmiddotmiddotmiddotmiddotmiddotmiddotmiddot-tmiddot Upper Limlt 0
20 middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotjmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotimiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddott 0 Lower Limit
19
0 1 2 3 4 5 6 7 8 9 10
TIC I
Fig 413 Mullion Temperature Profile With Heater On (Center)
Heat fluxes are computed identically to the method in Section 45 using the average slopes
from all nine runs The minimum value occurs just before to compressor turns on while
the maximum value occurs just before the compressor shuts off during normal cycling
The load is averaged over the cycle time which is approximately 50 for the test unit and
laboratory conditions The results are given in Table 44
Table 44 Experimental Results from Heater Analysis
Lower Profile Average W
(BtuIhr)
Upper Profile Average W
ffituhr)
qmullonfz 73
(249) 53
(181)
qmullonff 23 (78)
26 (89)
96 (32 7)
79 (270)
qmullon 88
300)
26
47 Determination of Qmisc
The load qoisc is comprised of three main parts The first is the load due to the evaporator
fan motor The fan that moves cool air in the cabinet also adds a thennalload Fans of this
type in use range from 8 - 16 watts The fan of our test unit is rated at 92 watts This
value must be integrated over the cycle time The cycle time for the unit is approximately
50 for the test conditions Thus the value of qfanave is 46 watts
The load qdefrostave is not determined experimentally Instead an estimate is obtained from
a similar study done by Turiel and Heydari (1988) This value is 5 watts which is an
average of the defrost heater input over the defrost cycle The defrost cycle can range from
10 - 12 hours of compressor run-time
The fmalload qcompave is detennined by measuring the cabinet surface temperature at the
region surrounding the compressor and computing the heat transfer locally The value is
found to be 2 watts Table 45 summarizes the results
Table 45 Miscellaneous Loads
Load W CBtuhr)
46 qfanave (15middotU
50 qdefrostave _07Ql
20 qcompave (68)
116 Qmisc (395)
27
s NUMERICAL SIMULATION
In this chapter a two-dimensional numerical model which is used to simulate the steadyshy
state heat transfer in the wall near the door seal is discussed The results from the model
include a computation of qwallff qwallfz and the complete temperature distribution across
the section The model is also used to estimate the additional cabinet load due to the
presence of an anti-sweat condenser tube embedded beneath the outer casing that runs
along the perimeter of the unit A separate model is presented which is used to simulate the
two-dimensional heat transfer across the door seal cross section The results are used to
determine qseal
51 Wall Model
A finite-difference technique is used to approximate the steady-state temperature
distribution in the wall section The technique is applied to solve the governing steady
two-dimensional heat conduction equation (assuming constant conductivity with no
generation)
(51)
Equation (52) is the basic fmite-difference representation of the conduction equation in a
homogeneous medium of constant conductivity with no heat generation (White 1988) In
Appendix F a complete list of all the model difference equations is provided
2(1+(3)Tij = (3Tij+l + Ti+lj+(3Tij-l + (3Ti-lj (52)
where (3 = (llxlly)2
28
Figure 51 is a sketch of the model representation of the refrigerator wall at the door seal region The dimensions shown are flexible parameters in the model The model allows for
slight changes in the geometry as well as changes in mesh size in both x and y directions
However the mesh size must remain uniform across the section
s5 s6
sl
Fig 51 Wall Heat Conduction Model Sketch
For each of N unknown nodal temperatures N simultaneous linear algebraic equations are obtained for N unknowns If N is large as is the case for this simulation an iterative
technique is preferred to solve the system ofequations A Fortran program has been
written to carry out the finite-difference iteration A copy of the code is given in Appendix
F A simple Guass-Seidel technique is employed for the differencing iteration At each
iteration an energy balance is done for the entire section In theory this balance should be
29
zero (heat entering) = (heat leaving) The iteration is continued until the difference
between heat entering and heat leaving is equal to 1 of the total heat entering the section
Table 51 defines the input parameters for the simulation
Table 51 Wall Simulation Input
Code Parameter Definition
To C (F) Exterior surrounding ambient temperature
Ti C (F) Interior ambient temperature
lan Wm-K (Btuhr-ft-F) Steel skin conductivity
kp Wm-K (Btuhr-ft-F) Plastic skin conductivity
kins Wm-K (Btuhr-ft-F) Wall insulation conductivity
heffo Wm2-K (Btuhr-ft2-F) Outside effective heat transfer coefficient
hefti Wm2-K (Btuhr-ft2-F) Inside effective heat transfer coefficient
dm mm (in) Steel skin thickness
dp mm (in) Plastic skin thickness
dx mm (in) Mesh size x direction
dy mm (in) Meshsizeydirection
sl mm (in) Wall width
s2 mm (in) Wall length
b mm (in) Effective Perimeter
s3 mm (in) Seal indentation
s4 mm (in) Seal width
s5 mm (in) Depth of steel skin into cabinet along seal boundary
s6 mm (in) Width of plastic skin along seal boundary
The model assumes that the boundary that lies along the door seal is adiabatic This allows
the separation of the wall section from the rest of the geometry in this region The seal and
door can then be treated separately later A simple calculation is done to validate this
assumption
30
Steel Skin (Refrigerator wall)
Seal (k = 02 Wm-K)
Fig 52 Non-adiabatic Door Seal
A 2 degC temperature difference AT is imposed across the seal This is a slight overshy
estimate based on the experimental data An estimate of the conductive heat flux is
determined from Eq (53)
ATqerror=k- (53) Ax
qrror =02 Wm-C o~Cm =20 Wm2
The heat flux ql for the fresh food compartment is determined in Appendix E to be 14418
Wm2 Therefore qerror represents approximately 13 of the total flux Hence this
term is neglected in this study
Two other possible sources of error are associated with the fmite-difference technique itself
(Ozisik 1980) The fIrSt is called truncation error and arises from the discretization of the
second-order derivative in the steady conduction equation The second is referred to as the
round-offerror which is due to the fact that numerical calculations are carried out only to a
finite number of decimal places Repeated solution with smaller increments shows that the
truncation error is negligible The precision of the energy balance is evidence that the
round-off errors are negligible
31
S2 Wall Simulation to Determine qwall
The finite-difference model is used to detennine the wall-side heat transfer along the steel
skin However more valuable information is yielded from the simulation The nodal
temperature distribution is detennined which gives insight into the direction and magnitude
of heat fluxes throughout the section The fresh food compartment and the freezer are both
simulated to detennine qwallff and qwallJz respectively Table 52 is the list of the values
used for the model input parameters for both cases
Table S2
Code Parameter
To C eF)
Ti C eF)
kIn Wm-K (Btuhr-ft-F)
kp Wm-K (Btuhr-ft-F)
kins Wm-K (Btulhr-ft-F)
heffo Wm2-K (Btuhr-ft2_F)
heffi Wm2-K (Btuhr-ft2-F)
dm mm (in)
dp mm (in)
dx mm (in)
dy mm (in)
sl mm (in)
s2 mm (in)
b mm (in)
s3 mm (in)
s4 mm (in)
s5 mm (in)
s6 mm (in)
Input Values
Fresh Food 210 (698) 40
(392) 540 (312) 015 (009) 0027 0015t 687 (121) 670 (118) 065
(0026) 25
(0098) 225
(0088) 25
(0098) 450
(1772) 2000 (7874) 2960
(11653) 225
(0088) 2025 (0797) 225
(0886) 2025 (0797)
32
Freezer 210 (698) -10
(140) 540middot (312) 015 (009) 0027 (0015) 687 (121) 641 (113) 065
(0026) 25
(0098) 28
(0088) 25
Jo098) 540
(2125) 2000 (7874) 1580
(6220) 28
(0110) 196
JO772) 224
(088t) 288
(1134)
The output from the simulation includes the entire nodal temperature field heat fluxes at
each node along the centerline heat fluxes from node to node along the steel skin beneath
the door seal and the value for qwallff and qwallcz These heat transfer values and the
nodal temperature distribution are listed in Appendix F
The quantities qwallff and qwallcz are determined by computing the heat fluxes from node to node along the centerline of the section subtracting the one-dimensional flux and then
multiplying by the cross sectional area for that node and summing to give the total heat
transfer rate The primary results are shown in Table 53
Table 53 Wall Simulation Results
Section
The temperature distributions are shown in the following two figures Figure 53 shows
the temperature contour for the fresh food results Figure 54 is the same plot for the
freezer results
Since the geometry of the refrigerator door is similar to that of the wall along the edges the
heat leakage to the food compartments along the door flange can be approximated as being
roughly the same as qwall This approximation of qdoor is a good means of estimating the
two prime contributors to the edge loss for various different refrigerators which may have
slightly different geometries as well as different material properties
33
i
3875
3625
TemplaquogtC)
-e
11111
20
18
16 3375
g 3125 14 -5 2875 ~ 122625 ~
2375~ 102125~
1875 8
1625
1375 6
1125
875 4
625
375
SteeVPlastic Liner Interface
Fig 53 Fresh Food Wall Temperature Distribution
34
i 4875
4625
4375
4125
3875
3625
3375 -
3125e g 2875
2625 ~ 2375 ~ 2125c (I)
1875 ~ 1625
1375
1125
875
625
375
125
Fig 54 Freezer Wall Temperature Distribution
Temp(OC)
20
15
10
5
0
-5
-10
35
53 Wall Edge Simulation to Determine qtube
The wall simulation is modified to include a constant temperature node placed beneath the
steel flange to represent the presence of an anti-sweat condenser tube The simulation is
perfonned for the specific conditions that are typical of the test unit as well as a range of
lateral tube locations For the test refrigerator the tube is located as shown in Figure 55
and is at 35degC (95 OJlt)
Outer Steel Skin
14625 mm 1
Inner Plastic Liner
Fig 55 Tube Location for Simulation
The quantity qtube is detennined by taking the fluxes along the vertical line to the left of
the tube subtracting the one-dimensional flux and then multiplying by the cross sectional
area for that node and summing to give the total heat transfer rate Again the fresh food
compartment and the freezer must be simulated separately to produce a total governed by
Eq (54)
(54)
Program output for the fresh food and freezer simulations is given in Appendix F Table
54 summarizes the results from the model
Table 54 Wall With Condenser Tube Simulation Results
Section Load W iBtubrl
qtubeff 46
(157)
qtubefz 28 (96)
qtube 74 (253)
qtube8ve (ave for 50 cycle time)
37 (126)
36
-I i c IJ
~
r 4875
4625
4375
4125
3875
3625
3375
3125
2875
2625
2375
2125
1875
1625
1375
1125
875
625
375
125
TempfC)
SteeVPlastic Liner Interface
35
30
25
20
15
10
5
Fig 56 Fresh Food Wall Temperature Distribution Including Warm Anti-sweat Tube
37
TempfC)4875
4625
4375
4125
3875
3625
3375 - 31258
2875g 2625fo 2375
3 2125 d vI 1875
~ 1625
1375
1125
875
625
375
125
SteeVPlastic Liner Interface
Fig 57 Freezer Wall Temperature Distribution Including Warm Anti-sweat Tube
38
40
30
20
10
0
-10
The heat fluxes at each node along the vertical line to the left of the tube are also computed
by the simulation This value quantifies the amount of heat that is moving toward the outer
boundary and is used to determine the percentage of heat entering the cabinet For the test
refrigerator this value is 18 for the fresh food compartment and 24 for the freezer
Several more simulation runs were done to find the effect of lateral placement of the tube on
the overall heat transfer and the percentage of heat entering Figure 58 and Figure 59
show the trends that are found
-~ a tUbe ~middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotlmiddotmiddotmiddot=middotmiddot=pmiddotmiddotmiddot=middot-1- =1
middot middot middoti middot middotmiddotmiddotmiddotmiddotmiddotmiddotmiddot bull middotmiddotmiddot i middotmiddotmiddotmiddot middotmiddot middotmiddot ~ middotmiddot
middotmiddotrmiddot-rmiddot 0 lwbeff middotlmiddotmiddot~middot Gmiddottmiddotmiddot9middotlmiddot
i i -0- lwbe i middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotimiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddot fz tmiddotEimiddotmiddot ~G- -~ -q- -
0 5 10 15 20 25 x(mm)
Fig 58 Load Due to Condenser Tube for Various Tube Placements
8
~ - 7
50
a 6
~ 5
~ en 4 ~
pound ~ 3
2
- 26
~ a 24
middots bO
pound 22c ~
~ 20
a = 18sect ~
16 0 5 10 15 20 25
x (mm)
Fig 59 Percentage of Heat Entering Cabinet for Various Tube Placements
39
54 Door Seal Simulation to Determine qseal
Another model is developed for the two-dimensional heat transfer through the door seal
This model is very similar to the one created for the wall section Once again a fIniteshy
difference technique is utilized to detennine the temperature distribution at steady-state
conditions Even though the cross sectional geometry of the seal is simplifIed to a square
with a hollow square with a centrally located cavity no closed-form solution can be
applied Therefore a simulation is needed
The fInite-difference representation of the two-dimensional steady Eq (55) using central
differencing is given by Ozisik (1980)
Ti-lj - 2Tij + Ti+lj + Tij-l - 2Tij + Tij+l = 0 (55) Ax2 Ay2
For this model a square mesh is applied reducing Eq (55) to
Ti-lj + Ti+lj + Tij-l + Tij+l - 4Tij = 0 (56)
x
Fig S10 Seal Simulation Mesh Layout
40
The nodes along the vertical surfaces at x=O and x=20 are subject to the convective
boundary conditions and governed by Eq (57) and Eq (58) respectively
2~xheffol 2~heffo2Ti+lj + Tij-l + Tij+l - (4 + k TiJ = - k To (57)
seal seal
2~heffffl 2~heffff2Ti-lj + Tij-l + TiJ+l - (4 + kseal Tij = - kseal Tff (58)
The nodes along the top and bottom outside surfaces are held at the prescribed temperature
profIles which are detennined from experimental data (see Section 41) The interior nodes
are subject to radiant e~change among themselves and conduction through what is assumed
to be stagnant air A closer look at the model of the hollow interior of the seal is shown in
Figure 511
Fig 511 Seal Cavity Mesh Details
Each interior node corresponds to a single gray surface with assumed emissivity of 09
Viewfactors for all surfaces are computed automatically before the iteration begins For
each iteration the effect of radiation within the enclosure is taken into account by updating
surface radiosities Jij Thus for nodes on interior surfaces an extra tenn is added to the
governing difference equation (Eb is the blackbody radiation)
41
~(J - Eb )1-pound IJ lj
A code written in Fortran is used to perfonn Guass-Seidel iteration of the difference
equations to compute the temperature distribution at mesh nodes (Code listing in Appendix
F) Once again convergence is based on an energy balance applied to the entire section
The iteration is continued until the difference between heat entering and heat leaving is
equal to 01 of the total heat entering the section Table 55 lists the input parameters
used in the model The fresh food compartment and the freezer compartment are simulated
separately
Table 55 Seal Simulation Input
Code Parameter Fresh Food Freezer
Number of nodes along outside edge 20 20
Number of nodes along inside edge 6 6 1 1Lx = fly mm (in) (0039) (0039)
210 210Outdoor ambient temperature degC (oF) (698) (698) 150 105Indoor local ambient temperature degC COF) 590J j509)
Outdoor heat transfer coefficient W m2-K 687 687 (121) (121)(Btuhr-ft2-F)
Indoor heat transfer coefficient Wm2-K 670 641 (118) (113)(Btuhr-ft2-F)
Gasket interior surface emissivity 09 09 03 03Gasket conductivity Wm-K (Btuhr-ft-F) (0173) (0173)
Wall-side Temperature Boundary 1905 - 1977x 1813 - 3475x Condition degC Door-side Temperature Boundary 1913 - 1384x 1852 - 2341x Condition degC
42
The load results are summarized in Table 56 below The program output is listed in
AppendixF
Table 56 Seal Simulation Results
Load W Section (BtuIhr)
10 Qsealff (34)
ljQsealfz (Sn
25qseal (85)
The steady-state temperature distribution is shown in the figures below Figure 512 is the
fresh food simulation and Figure 512 is the freezer simulation The direction of the heat
flow through the section is easily seen from these plots
43
Wall-side Boundary Temperature (C)
~~
I 20
195
i 19t 0
8 ~ 1859 -- ~
isis ~ ampJ gtshy 18 ~
11 ~ S ~ 175~
~ 17
165
x(mm)
Door-side Boundary
Fig 512 Seal Temperature Distribution (Fresh Food)
44
Wall-side Boundary Temperature (C)
Ii 19
185
18i f IQ 5 IQ
175-is-is I s 17j ~
5e 0C= 165
~ ~ 16
155
x(mm)
Door-side Boundary
Fig 513 Seal Temperature Distribution (Freezer)
45
6 DISCUSSION OF RESULTS
The heat transfer values detennined from the experimental analysis and the numerical
simulations are the various components that embody the cabinet load on the refrigerator It
is important to separate cabinet loads from system loads The system load can be thought
of as the total electrical energy consumption of the unit It has four basic components (i)
the compressor (ii) fans (iii) anti-sweat heaters and (iv) defrost heaters The first two
components the compressor and fans are the cost of removing heat from the cabinet This
amount of heat is equal to the cabinet load divided by the COP of the system The typical
energy consumption is shown schematically in Figure 61
System Load (Energy Consumption)
Defrost Heater (averaged over time
cycles every 10-12 hours of compressorrurt-time)
TuneCycle
Fig 61 Refrigerator System Load Graph
In a study done by Turiel and Heydari (1988) the compressor and fans accounted for 84
of the total system load for an 180 cubic foot top-mounted refrigerator Staley (1992)
found this value to be 86 for a similar unit Both of these studies used system analysis to
determine these numbers The energy consumption of the components were monitored
during operation The energy consumption of our test refrigerator can be determined in a
reverse manner from the cabinet load data If a COP of 1 is assumed the test refrigerator
46
compressor and fans accounts for 86 of the energy consumption to cool the cabinet This
compares favorably with the fmdings of Turiel and Heydari (1988) and Staley (1992)
Figure 62 is a schematic of the cabinet loads One possible load that is not included in the
figure is the heat input associated with the defrost drain tube that runs through the back
wall However this term is probably small relative to the other contributors
Cabinet Load
qseal qdoor
qwall
qmullon
qdefrostave
Fig 62 Cabinet Loads Graph
All the loads are determined in this study from either experimental measurements
numerical simulations or both Most of the loads are quasi-steady that is they do not
fluctuate significantly over the cycle time of the refrigerator There are four loads shown in
Figure 61 that are cyclical in nature The three loads that appear only while the
compressor is running are qcomp qfarb and qtube Also the refrigerator is subjected to a
load every time ice build-up is removed by the defrost heaters This load is averaged over
its own cycle time and shown in the graph as qdefrostave
47
61 Comparison of Simulation Results with Experimental nata
The majority of the cabinet loads are detennined from experimental data with the exception
of qseal and qtube The wall and door flange loads aremiddot also found from the numerical
simulation (see Chapter 5) The two-dimensional model detennines the wall-side heat
transfer along the steel skin into the food compartments No model is available to directly
detennine the heat transfer on the door-side However since the flange geometry on the
door-side is similar to the wall the value for qwall is considered to be a good estimate for
qdoor Table 61 gives these values determined from experimental measurements and the
simulation
Table 61 Comparison of Simulation and Experimental Values for qwall and qdoor
Experimental Result W Simulation Result W (BtuIhr) (BtuIhr)
qwallff 28 (96)
28 (96)
qwallz 21 (72)
27 (92)
qwall 49 (168)
55 (188)
ldoorff 33
(112) 28 (96)
qdoorfz 33
(112) 27 (92)
qdoor 66 (224)
55 (188)
The model predicts qwall to within 57 of the experimental value The agreement of the
estimate of qdoor with the experimental value is within 90
Some of the shortcomings in the model used in this investigation are
(i) Only the wall is modeled Ideally the entire region should be considered including the
door and seal (see Figure 11)
(ii) The flange geometry is simplified The steel casing skin in the flange region may bend
in more complex ways Also the plastic liner varies in thickness near the door seal
(iii) The mesh must be unifonn There is no means to vary how fme the mesh can be The
ideal situation would be to have a fine mesh near the edges and a course mesh far from the
seal
48
62 Mullion Analysis
The single largest edg~ load is found in the mullion section (329 of qedge and 94 of
qtol) This load is due to the electric anti-sweat heater installed on the backside of the face
plate The heater is rated at 10 watts and approximately 88 of that input enters the
interior of the cabinet as a thennalload This is probably due to the small surface area
exposed to the room and the low amount of convective heat transfer in the channel between
the fresh food and freezer doors With the heater on 88 watts is measured enter the food
chambers With the heater off only 16 watts enters the interior The addition of the
heater increases the mullion load 55 times Generally it is not necessary to use the
mullion heater at all times However for the test environment the heater nearly all the time
to eliminate sweating under the laboratory conditions
63 Seal Analysis
The heat conduction directly through the seal accounts for the smallest portion of the edge
loss (94 ofqedge and 27 of qtol) The numerical model to detennine these values uses
a simplified representation of the complex cross sectional geometry of an actual door seal
The various air pockets are reduced to a single hollow void There is no experimental data
to verify the model However the numbers and trends resulting from the simulation are
reasonable
64 Anti-sweat Condenser Tube Analysis
Thennocouple drag tests were perfonned to give insight into the nature of the temperature
profIles at the wall steel flange with the presence of an anti-sweat condenser tube The wall
heat transfer simulation model was modified to include the effect of this tube The heat
conduction to the interior increased by 76 at the wall flange region The amount of
additional loading due to the tube depends on several parameters location of the tube
temperature of the circulating refrigerant and local wall geometry Although the model is
flexible enough to handle vari01~S temperatures and limited geometrical changes only the
influence of tube position was investigated As the tube is moved towards the interior the
load increases For the test refrigerator about 20 of the heat flow was directed to the
interior compartments primarily along the steel skin
49
6S Overall Cabinet Load
The overall cabinet load is defined as a sum of three parts
(61)
The edge load is
qedge = qwall + qdoor + Qseal + Qrnullon + qtubeave (62)
where
qwall
qtubeave
heat input due to the conduction along the wall steel flange
heat input due to the conduction along the door steel flange
heat conduction directly through the door seal
heat input due to conduction in the mullion region with the additional input from anti-sweat heater
heat input due to cabinet anti-sweat condenser tube averaged over the cycle time
heat input due to cabinet anti-sweat condenser tube
qmulloff heat input due to conduction in the mullion region electric heater off
The terms of Qrnisc are defined as
qmisc = qfanave + qdefrostave + qcompave (63)
where
qfanave heat input from the evaporator fan averaged over the cycle time
qdefrostave heat input from the defrost heaters averaged over defrost cycle time
qcompave heat input from elevated exterior walls near the running compressor
Table 62 presents the overall cabinet load analysis results
50
Table 62 Overall Cabinet Loads
Load W Load Btuhr Total
qlD 550 1876 591
qedge 265 903 285
Qwall 49155 167 188 53
Qdoor 66155 2251 188 71
Qseal 25 85 27
Qmullon 88 300 94
Qtubl ngt 37 126 40
qmisc 116 395 124
Qfanave 46 157 49
Qdefrost ave 50 170 54
qcomoave 20 68 21
qtot 931 3174 100
Simulation Results
All loads are detennined experimentally with the exception oflsea1 and qtubeave The
values for qwall and qdoor are detennined from both experimental data and numerical
simulations Edge loss per unit length along fresh food perimeter is 29 Wm (30 Btuhrshy
ft) the loss per unit length along the freezer perimeter is 44 Wm (46 Btuhr-ft) and the
loss along the mullion section is 123 Wm (128 Btuhr-ft) with the heater on and 22 Wm
(23 Btuhr-ft) with anti-sweat heater off
The largest single load is the one-dimensional conduction through the walls and doors
The edge load comprises 285 of the total a significant portion The largest edge load is
due to the electric anti-sweat heater that is installed in the mullion section The smallest
edge load is due to the heat conduction through the fresh food and freezer door seals The
losses at the wall-side and door-side flange regions account for 53 and 71 of the total
load respectively These could be considered together since the pathway of heat transfer is
very similar If that were the case the sum of qwall and qdoor would be the second largest
contributor to the overall cabinet load The influence of an anti-sweat condenser tube is
reflected in the value of qtubeave Although this additional load is larger than qwall it must
be integrated over the refrigeration cycle timewhich is 50 of the cycle time for the test
unit The tube boosts the heat transfer along the wall flange by 76
51
To round out the cabinet load three miscellaneous loads are considered The evaporator
fan motor produces a heat load within the cabinet which is considered to be equal to the
power rating of the fan The automatic defrost feature is another thermal load that is
cyclical appearing about every ten to twelve hours of compressor runtime The fmalload
is due to the elevated exterior skin temperature near the compressor when it is running All
three of these loads are averaged over their cycle times for comparison with other quasishy
steady loads As a total qmisc represents 124 of the overall cabinet load
Opportunities to decrease the one-dimensionalload are available The emphasis has been to
develop super-insulations to be installed in the refrigerators Some being considered are
vacuum panels aerogels and vacuum packed powder insulations The disadvantages of
this improvement lies within the need to develop a cost-effective technique for fabricating
and installing such technologies compatible with high-volume manufacturing Also edge
losses and panel connection losses must be minimized due to the difficulty in making a
panel the size of refrigerator interiors Reliability of the seal and perfonnance of the outer
envelope need to be ensured over a long period of time ie the expected life of the
product
The possibilities of reducing the loads along the edge of the refrigerator aperture are
somewhat less apparent One method of reducing quasi-steady heat conduction along wall
and door flanges is to raise the inside cabinet wall temperature by minimizing interior film
surface heat transfer coefficients This could be accomplished by the use of low-emissivity
surfaces on the interior walls or on sections nearest the edges The need for an anti-sweat
device for the perimeter is also eliminated supplying a two-fold savings by reducing the
cabinet ioad and the system energy consumption The need for an electric mullion heater
might also be done away with by the same means The drawback again would be to make
such modifications acceptable and cost-effective for manufacture
The remaining miscellaneous loads provide some chance for improvement If the
efficiency of the fans is increased the energy use of the refrigerator can be reduced The
option of moving the fan motor outside the cabinet leads to other problems The motor
shaft must pierce the wall providing another path for heat leakage Also frost built-up on
the shaft would be a costly and difficult problem to eliminate If the compressor and
condenser were located near the top of the refrigerator they can operate more efficiently
Heat can be more readily convected away eliminating the need for the condenser fan
(Turiel and Heydari 1988) Frost fonnation in the freezer varies significantly depending
52
on the ambient conditions and the freezer usage The defrost cycle could be made more
energy efficient with the addition of adaptive controls All of these improvements would
require redesign of the product and the manufacturing process This is a very expensive
alternative which would need to be justified by the associated energy savings
53
7 SUMMARY OF CONCLUSIONS
The following is a list of the important findings produced from this study
(i) The edge loading accounts for a significant portion of the total cabinet load For the
test unit used in this study an 18 cubic foot top-mount refrigerator this load was
approximately 30 of the total load The load includes losses along the wall and door
flanges conduction through the door seal mullion loading with an electric anti-sweat
heater on and additional thennal input from an anti-sweat perimeter condenser tube
(ii) The presence of an electric anti-sweat mullion heater boosts the mullion loading by
a factor of approximately 5
(iii) The presence of an anti-sweat condenser tube around the perimeter of the refrigerator
increases the wall flange load by approximately 75
(iv) The presence of the door air damt reduces the temperature difference across the door
seal to 35 of the temperature difference between the interior and exterior
environments
(v) The hypothetical elimination of the additional load due to the electric anti-sweat
mullion heater reduces the edge loading to approximately 22 of the total cabinet
load
(vi) The hypothetical elimination of the load due to the anti-sweat condenser tube reduces
the edge loading to approximately 25 of the total cabinet load Ifboth anti-sweat
devices were not needed the edge loading would be further reduced to only 17 of
the total
(vii) During the course of this investigation it was concluded that the experimental and
numerical methods developed are applicable to most refrigeratorfreezers that are
produced today
t The portion of the door liner that extends into the cabinet along the wall
54
REFERENCES
Braswell A 1988 Impact of CFC Regulations on the Air Conditioning and Refrigeration Industry International Jow-nal ofRefrigeration Vol 11 No6 p 385
Cabot Corporation 1987 CAB-O-SIL Fumed Silica Properties and Functions Tuscola n pp 12-15
Clausing A M 1983 Natural Convection Correlations for Vertical Surfaces Including Influences of Variable Properties ASME Jow-nal ofHeat Transfer Vol 105 No 1 pp 138-143
Incropera FP and Dewitt DP 1985 Fundamentals ofHeat and Mass Transfer Second Edition John Wiley and Sons New York
Ingersoll LR Zobel OJ and Ingersoll AC 1954 Heat Conduction with Engineering and Geological Applications McGraw-Hill Book Company New York
Little AD Inc 1982 Refrigerator and Freezer Computer Model Users Guide Cambridge Massachusettes
Micropore International Ltd Microtherm Thermal Insulation Worcestershire England Section 1
Nix GH Lowery GW Vachon RI and Tanger GE 1967 Direct Determination of Thermal Diffusivity and Conductivity with a Refined Line-Source Technique Progress in Astronautics and Aeronautics (Vol 20) Thermophysics ofSpacecraft an Planetary Bodies Academic Press New York pp 865-878
Nix GH Vachon RI Lowery GW and McCurry TA 1968 The Line-Source Method Procedure and Iterative Scheme for Combined Determination of Conductivity and Diffusivity Thermal Conductivity Proceeding of8th Conference
Ozisik MN 1980 Heat Conduction Wiley-Interscience Publishing New York pp 486-487
Staley D 1992 Personal Communication Graduate Research Assistant University of Illinois Urbana
Turiel I Heydari A 1988 Analysis of Design Options to Improve the Efficiency of Refrigerator-Freezers and Freezers ASH RAE Transactions Vol 94 Part 2
Van der Held EFM and Van Drunen FG 1949 Physika Vol 15 No 10 p 865
White PM 1988 Heat and Mass TranSer Addison-Wesley Publishing Reading Mass pp 145-160
55
APPENDIX A FUMED SILICA INVESTIGATION
A ~ 1 Introduction
Fumed silica is a micro-porous powder comprised of submicron particles of amorphous
silica bonded together in a cellular structure Several grades of silica are available offering
a selection ofdifferent grain sizes and chemical treatments Fumed silica is commonly used
to provide thickening thixotropy suspension and other related properties in liquid
systems In dry systems it is used to promote free flow frictionizing and anti-blocking
properties Thus it is a versatile additive in materials such as inks coatings adhesives~
and silicon rubber (Cabot Corporation 1987)
The thermal insulating properties of this material have been somewhat less widely applied
however fumed silica as an insulation displays some interesting properties Fumed silica
insulations are commercially available and have become a more popular material for certain
specific applications In this section the results of an investigation of the thermal
properties of one type of fumed silica is presented
A2 Thermal Properties
As an insulator fumed silica uses the microporous principle to reduce thermal conduction
to the theoretically lowest possible levels (Micropore International Ltd 1988) Most
conventional insulations rely upon voids normally occupied bj alt aS the meanS ot
minimizing heat transfer through the material Therefore it is important to maintain these
voids for maximum insulation Fumed silica is comprised of tiny spheres with diameters
of the same order of magnitude as the mean free path of the molecules in the air
Therefore when these spheres are packed closely together gaseous conduction and
convection are minimized The cell size is sufficiently small to keep convective currents
from forming and to trap gas molecules to rebound elastically thereby not imparting their
energy to slower moving molecules In addition solid conduction is minimized by the fact
that silica is a material with intrinsically low thermal conductivity These unique properties
make fumed silica an attraCtive alternative to conventional insulations
56
A3 Experimental Method
Thennal conductivity and thennal diffusivity are the properties detennined from our
experimental study Many methods exist for establishing the thennal properties of a given
substance Both steady-state and transient procedures are available The hot-wire method
is a the transient procedure used in this study
The practical form of the hot-wire method is given by Van derHeldand Van Dronen
(1949) who used it to detennine conductivities of liquids Nix et al (1967) elaborated to
give a method for the simultaneous detennination of both thennal conductivity and thennal
diffusivity Therefore it is possible to detennine both conductivity and diffusivity by
passing a known amount ofcmrent through a heater wire embedded in the test material and
recording the temperature at a point on the wire and at a fixed point from the wire over the
period of the test From the temperature history of the point contiguous to the hot-wire the
conductivity can be detennined directly From the temperature history of the point at a
fixed distance from the hot-wire the diffusivity may be computed Both procedures are
outlined in the following section
A4 Theory
The temperature at any point in an infinite solid containing a line heat source of constantshy
rate is a function of the position time from initiation the thennal conductivity of the
material and the magnitude of the source This is shown mathematically by Ingersoll et aI
(1954) The cylindrical temperature field is expressed as
T=~l- exp-x2) dx (Al)21tk x
II
In series fonn
(A2)T=~[-amp-lnp+L-L+L_ ]21tk 2 21 4middot2 63
57
where
q = Heat input per unit length of wire [W1m]
k = Thennal conductivity of the material [Wm-K]
a = Thennal diffusivity of the material [m2s]
t = Elapsed time from heat liberation [s]
r = Radial distance from line-source [m]
Ce = Eulers constant (05772157 )
The temperature change between two times tl and t2 is accurate to better than one percent if
the value of ~ is less than 016 for a point very close to the line-source
(A3)
Equation (A3) is used in this case to detennine the thennal conductivity since the
diffusivity a and the radial distance T no longer appear in the relation Therefore
knowing the temperature at two different times during the test gives the conductivity
directly given that the value of ~ remains small This is achieved by choosing a point very
near if not contiguous to the hot-wire itself In our study a graphical method is used to
detennine the conductivity If the temperature versus the natural logarithm of the time is
plotted a straight line should be seen whose slope is equal to q4nk
Once the conductivity of the material is detennined the diffusivity can be found by the
method proposed by Nix et aI (1968) The temperature at a fixed and known distance
from the hot-wire must be monitored over the time period of the test Now since ~ gt 016
the diffusivity does not drop out of Equation (A2) Rewriting Equation (A3) as
(A4)
where
~2 ~4 ~6 ]r(~)= [ -~-ln~+---+-- (A5) 2 211 4middot2 6middot3
58
therefore (A6)
Using the temperature at the fixed location as an input Equation (A6) can be solved iteratively by means of Newton-Raphson technique to find the parameter ~ and thereby
yielding the thermal diffusivity a
AS Test Apparatus
Figure A1 is a sketch of the test apparatus used to collect thermal property data This
device provides a wide range of silica densities for packed tests Each half of the apparatus
is packed separately to the same density and then pressed together sandwiching the heater
wirethermocouple assembly between them
Remove bottom plate and press together with right half
Insert heater wirethermocouple assembl)
Remove bottom plate and press together with left half
Compact both halves to same density
Fig AI Fumed Silica Test Apparatus
Prior to loading the unpacked silica into the test cylinders the mass is carefully recorded
Each test cylinder has graduated marks to allow the volume of the sample to be computed
The density is then computed from the measured mass and volume At higher densities it
59
is sometimes necessary to load and compact several times Figure A2 is a schematic of the
heater wirethermocouple assembly and the entire test facility
Switch
Ammeter
Power Source
Cylindrical Test Section
Thermocouple for Conductivity
Data Acquisition System
Thermocouple for Diffusivity
Fig A2 Fumed Silica Test Facility Schematic
The heater wire used for all tests is 30 A WG nichrome wire with a nominal resistance of 2214 Wm Both thermocouples are type T 36 A WG Once the test sample is in place
the switch is closed allowing cUITent to pass through the heater wire The heat input per
unit length of the wire is determined from
(A7)
where q = Heat input per unit length of wire [Wm]
I = The input cUITent [Amps]
R = Heater wire resistance per unit length [Wm]
60
Knowing the heat input per unit length the temperature contiguous to the heater wire and
the temperature at a fixed distance from the heater wire over the duration of the test eqs
(A3) and (A6) can be solved This yields the conductivity and diffusivity respectively
A6 Results
All results presented in this section are from tests petfonned with a material sample donated
by Cabot Corporations Cab-O-Sil Division The silica is an untreated sample EH-5 with
a bulk density of 25 Ibsft3 and a nominal particle diameter of 70 angstroms Several tests
are petfonned at various densities The thermal conductivity is determined graphically as described above while the diffusivity is determined using a Fortran code to pe~orm the
Newton-Raphson iteration also outlined in Section A4
A total of seven different bulk densities are tested Each test consists of three runs at three
different power levels The temperature history is recorded for both thermocouples
Figure A3 is a plot of the temperature for the duration of a typical test for unpacked silica
70~--~----+----r----~-----~----+----r
10001
middot middot middot o 05 Ampsmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddot o 04 Ampsi ~ i
I i I I i oo~ct 60 IIJatr-T50
1 LL~40
1 ~ 1 010 1 ltgtom
JPi i30 i 0I1 o 03 Amps 1 I I
20~--~----+----r----~-----~----+----r
-10 o 10 20 30 40 50 60 70 Time (sec)
Fig A3 Time vs Temperature for Unpacked Run
61
To graphically detennine the thennal conductivity the temperatme data must be plotted
against the natural logarithm of time Figure A4 gives this plot along with the equations
that represent linear curve-fits to the straight portion of each curve
70~----~--------+------+--------~----~----~--------+-----~
60 ~ =l-LL-~--o T ~ 86839 ~ 1376 ~(t) I
50 ---f--H-deg--tfjtshy ~ T =11108 + 97346 m(t)
40 IT_oroJ~-
30 middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotImiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotsectmiddotmiddotmiddotmiddotmiddotImiddotmiddotmiddotmiddotmiddotmiddotmiddot~middotmiddotmiddotmiddot109~~Q9 T= 18431~ + 493 ~(t) 0
~ e i i i
20~----~--------+------+--------~---------~~----+------r
05 1 15 2 25 3 35 4 45 In (time)
Fig A4 Natural Log Time vs Temperature for Unpacked Run
All three curves should yield the same conductivity for the sample The conductivity is
detennined from the following relation
k= 12R (A8)4n(slope)
Table AI gives the average conductivity for each density level This is the average for the
three input cmrents used These results are also shown graphically in Figure A5
62
Table AI A verage Fumed Silica Conductivity for Various Bulk Densities
est
1
2
3
4
5
6
7
0024
0023
0022 -~ ct 0021
~ e 002
~
0019
0018
0017
i
~i
I I I I Imiddotmiddotmiddot_middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotimiddot_middotmiddot middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotimiddot-middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot
1i111
~ ~ iii
_I_1_1_1
I I I I I middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot middotmiddotmiddotmiddotmiddotmiddotmiddotfmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddot -r-t-o-rldegoo---shy
25 3 35 4 45 5 55
Density (lbsff)
Fig AS Conductivity vs Bulk Density
From the temperature data collected from the second thennocouple the thennal diffusivity
is computed (see Section A4) This thennocouple lies 3 mm (0118 in) from the heater
63
wire The output from the diffusivity iteration is provided in Table A2 A graphical
representation is given in Figure A6
Table A2 Average Fumed Silica Diffusivity for Various Bulk Densities
Test
Average Diffusivity m2s (ft2Jhr)
1 210 x 10-7 (000813)
2 166 x 10-7 (000643)
3 159 x 10-7 (000616)
4 155 x 10-7 (000600)
5 153 x 10-7 (000592)
6 No Data Available
7 151 x 10-7 (000585)
00085 -+----+-----f----+----+----+--_+_
I
middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1 ~0008
I I I I ~
I middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotfmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot Tmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot ~ 00075
~-shyf i ~ ~ ~ i ++middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotfmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot0007 i iii
~ rn ~ ~ i i~
(jj bullbullbullbullbullbull1bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullJLbullbullbullbullbullbullbullbullbullbullj ~ 00065o ~ middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot0006
I I I 00055 -+----+-----f----+----+----f--_+_
25 3 35 4 45 5 55
Density (lbsff)
Fig AS Diffusivity vs Bulk Density
64
A7 Conclusions
The primary conclusion from this experimental study is the fact that the thennal insulating
properties of fumed silica powder increase as the bulk density of the material increases
Although this study presents a limited range of density values the trends that were
expected are seen to be true The conductivity values are expected to reach and even
surpass those of CFC-blown foams that are used in household refrigerators Further
testing is needed to provide data that supports this expectation In addition testing in this
study was strictly limited to a single variety of silica This particular type of silica is not
necessarily the best candidate for thermal insulation applications Silica powders are by
nature hydroscopic This affinity for water has adverse effects on its thermal insulating
properties However silica powders are now produced with a special treatment which
transforms the material into a hydrophobic material Therefore if these new materials
maintain the thermal properties and density trends of the hydroscopic type they become
even more preferred insulators Once again data needs to be obtained to support this
notion Fumed silica offers a competitive alternative to the existing CFC-blown foams
without the obvious environmental drawbacks It is completely inert recyclable and
reusable It also competes well when comparing cost values CFC-blown foams are
between 003 - 007 $ft2_R-Value whereas fumed silica powder are between 005 -025
$ft2-R-Value The discrepancies are close enough to merit true consideration
AS Thermal Diffusivity Newton-Raphson Iteration Source Code
program difsivty implicit none double precision condqtime(lOO)temp(lOO)guessradiusalpha
+ dif(lOO)sumavedifgcurrentmasslengthpi + density integer nikrun OPEN (2file=Oiffusivityoutlposition=rewind) OPEN (3file=Oiffusivityinposition=rewind) OPEN (4file=Oiffusivityout2position=rewind)
print Enter input current in amps readcurrent printEnter calculated conductivity in Wm K readcond print Enter thermocouple distance in meters readradius print Enter mass of sample in grams readmass print Enter compacted length of sample in em readlength print Enter number of timetemperature data points
65
c
readn 5 print enter initial quess for beta
readquess c
pi=31415927 q=currentcurrent2214 density=(mass1000)laquopi4)(003844)(lenqth100raquo
c c check to see if converqence will occur c print Enter data point l c print (time and temp with a blank separatinq the two) c readtime(1)temp(1) c call diffus(condqtime(1)temp(1)quessradiusalphaq) c printinitial q=q c if (abs(q) qt 05) then c qoto5 c endif c
do 10 i=1n read(3) time(i)temp(i)
10 continue c
print print Input Current= current print write(2) Input Current= current write (2 )
c sum=OO do 20 k=1n call diffus(condqtime(k)temp(k)quessradiusalphaq) print Diffusivity for data pointk =alpha write(2) Diffusivity for data pointk =alpha write(4) alpha dif(k)=alpha sum=sum+dif(k)
20 continue c
avedif=sumn c
print print print INPUT print Conductivity=cond Wm K print Heater Input=q Wm print Thermocouple Distance=radius m print- print OUTPUT print Sample Density=density kqm3 print Averaqe Diffusivity=avedifmiddot m2s
c write(2) write(2) INPUT write(2) Conductivity=cond Wm K write(2) Heater Input=q Wm write(2) Thermocouple Distance=radius m write (2 ) write(2) OUTPUT write(2) Sample Density=density kqm3 write(2) Averaqe Diffusivity=avedif m2s
c c
pause stop
66
end
subroutine diffus(condqtimetempguessradiusalphag) implicit none double precision condqtimetempbeta(100)radius
+ f1f2f1pf2ptempf2tempf2pggppialphaCe + signfactol integer jkmn
c Ce=5772157 pi=31415927 beta (1) =guess tol=l j=l
c c begin Newton-Raphson iteration to find beta and ultimately alpha c
while (tol gt 0001) c print betaj =beta(j)
f1=-Ce20 - log(beta(j)) flp=-l Obeta (j) f2=00 f2p=00
c c start loop to compute the summations for f2 and f2 prime
do 10 k=2162 m=k2
c this loop gives the factorial for the kth term fac=10 do 5 n=lm
fac=facn 5 continue
sign=(-1)laquok+2)2) tempf2=laquobeta(j)k)sign)(kfac) tempf2p=laquobeta(j)(k-1))sign)fac f2=f2+tempf2 f2p=f2p+tempf2p
10 continue
c c compute the value of G and G which are both functions of beta c these will be used to update beta in the Newton-Raphson iteration c where beta(n+1)= beta(n)- GG
g=laquo20picondtemp)q)-(f1+f2) gp=- (flp+f2p)
c print g=g c here we check to see if the convergence criterion suggested c by Nix is met for the initial beta chosen if not we must jump out of loop c if (j eq 1) then c if (abs(g) qt 05) then c printconvergence not satisfied c printtry a s~aller guess for beta c return c endif c endif c c update the value of beta and compute a tolerance value c that will be used to check for convergence
beta(j+1)=beta(j)-(ggp) tol=abs(beta(j+1)-beta(j))
67
j=j+1 c protect against infinite looping
if (j eq 100) then goto 101
endif repeat
c c if the iteration converges then compute the value for diffusivity
alpha=(10(40timeraquo(radiusbeta(jraquo2
c c
101 return
68
APPENDIX B ONE-DIMENSIONAL SIMULATION SOURCE CODE AND OUTPUT
B1 Source Code
CPROGRAM FrigWall--Steady-State Heat Conduction with Convective and CRadiative Heat Transfer from interior and exterior surfaces C Programmed by AM CLAUSING
LOGICAL SI DIMENSION RA(2)XNU(2)R(2)H(2)HR(2)TF(2)TW(2)DT(2) COMMON AXLWXLC(2)HC(2)T(2)XKWBETANMAXSIE(2)SIGMA
CDetermine- direction of output read and print input data NCASE=l
1 CALL DATAIN(NCASEIUOUT) NCASE=NCASE+1 QOLD=O TW(1)=T(1)+1(T(2)-T(1raquo TW(2)=T(2)-1(T(2)-T(1raquo
CCalculate wall resistance RW=XLWXKWA DO 3 N=lNMAX DO S J=12
CCalculate the radiative equivalent heat transfer coefficients HR(J)=SIGMAE(J)(T(J)2+TW(J)2)(T(J)+TW(Jraquo
C Calculate the film temperatures TF(J)=(T(J)+TW(Jraquo2
CCalculate the convective heat transfer coefficients CALL GASPT(lTF(J)RHOXMUXKCPGRBPRIER) DT(J)=ABS(TW(J)-T(Jraquo RA(J)=PRGRBXLC(J)3DT(J) IF(RA(J) LT1E9) THEN
XNU(J)=0S2RA(J)2S ELSE
XNU(J)=09RA(J) 3333 ENDIF H(J)=XNU(J)XKXLC(J) IF(HC(J) NE O) H(J)=HC(J)
CCalculate surface resistances R(J)=l(H(J)+HR(JraquoA
S CONTINUE CCalc~late total resistance heat flow rate and surface temperatures
RT=R(1)+R(2)+RW Q=(T(2)-T(1raquoRT TW(l)=T(l)+QR(l) TW(2)=T(2)-QR(2)
CCheck for convergence If solution has converged exit loop ERRQ=ABS(Q-QOLD)100Q QOLD=Q IF(ERRQLT OS) GOTO 7
3 CONTINUE 7 WRITE (IUOUT 101) Q ERRQ (H (J) HR (J) RA (J) XNU (J) TW (J) DT (J) R (J) RT
2 J=l2) 101 FORMAT( Q =F61 W10XERRQ =FS2 T12 hconvT22hradT33
2 RaT44NuTS2 TsurT62 DeltaTT72RRtotT10 [Wm2-KjT20 2 [Wm2-KjTS3 [KjT63 [Kj InsideF72F92E133F91 2 F101F91F113 OutsideF62F92E133F91F101F91F113) DO 9 J=l2 IF(HC(J) NE bull O) WRITE (IUOUT 103) J
9 CONTINUE 103 FORMAT( NOTE hconv(I1 ) was specified not calculated)
GOTO 1 END
69
C SUBROUTINE DATAIN(NCASEIUOUT) LOGICAL SI COMMON AXLWXLC(2)HC(2)T(2)XKWBETANMAXSIE(2)SIGMA DATA AXLWXKWXLCHCTENMAXSIGMA2990360245315 2 20277297 959510567E-8
CDefinition of NAM NAMELIST NAMAXLWXKWXLCHCETNMAXBETASI CHARACTER FNAME60CDATE9CTIME8 PARAMETER (IUIN=7)
CIF First Case Open Files Write Program Description and Date IF (NCASEEQ 1) THEN
WRITE (6 100) 100 FORMAT( TYPE NAME OF INPUT DATA FILE)
READ( (A) ) FNAME COpen input and output files
OPEN (7FILE=FNAME) REWIND 7
C OPEN (10FILE=Plots-FNAME) C WRITE(6122) Plots-FNAME C122 FORMAT( COMMA DELIMITED PLOTTING FILE IS A)
WRITE(6118) 118 FORMAT (T10 DIRECT OUTPUT TOT20 SCREENT36 Type 6
2 T20 OUTPUT FILET36 Type 8T20 PRINTERT36 Type 9) READ() IUOUT IF(IUOUTEQ8) THEN OPEN (8FILE=Answers-FNAME) WRITE(6120) Answers-FNAME
120 FORMAT( OUTPUT WILL BE WRITTEN IN FILE A) ENDIF CALL DATE(CDATE) CALL TIME(CTIME)
CWrite Program Description and Date WRITE(IUOUT102)CDATECTIME
102 FORMAT( Program FrigWallT60 Date A10 Version 8 August 1991T60 2 Time A9 Programmed by AMClausing) ENDIF
CRead and Write Input Data READ(IUINNAMEND=999) WRITE (IUOUT 104) NCASETXLCEXLWXKWA
104 FORMAT ( CASE NUMBER 12 2 Ambient Temperatures IK] InsideF616X OutsideF61 2 Characteristic Lengths 1m] InsideF626X OutsideF62 2 Surface Emissivities8X InsideF626XOutsideF62 Wall
Thickness 2 F63 mT27 ConductivityF63 Wm-K2x AreaF52 m2) RETURN
999 WRITE (IUOUT 199) 199 FORMAT ( ALL INPUT DATA HAS BEEN PROCESSED) 991 CLOSE(10)
IF(IUOUTEQ 8) CLOSE(8) STOP END
C SUBROUTINE GASPT(NGASTRHOXMUXKCPGRBPRIER)
C PROGRAMMED BY A M CLAUSING VERSION APRIL 1982 C PROPERTIES OF GASES IN SI UNITS(TGTO) OR ENGLISH UNITS(TLT O) C FUNCTIONAL REPRESENTATIONS USED ARE OF THE FORM Y=ATB C ARRAYS A AND B CONTAIN THE RESPECTIVE CONSTANTS C INPUT C NGAS - NGAS=l IS AIR NGAS=2 IS NITROGEN C T ---- ABSOLUTE TEMP (K) OR NEGATIVE OF ABSOLUTE TEMP (R) C OUTPUT C RHO -- DENSITY (KGM3) OR (LBMFT3)
70
C XMU -- VISCOSITY (KGM-S) OR (LBMFT-S) C XK --- THERMAL CONDUCTIVITY (WM-K) OR (BTUHR-FT-R) C CP --- SPECIFIC HEAT (JKG-K) OR (BTULBM-R) C GRB -- GBETAXNU2 (1M3-K) OR (1FT3-R) C PR --- PRANDTL NUMBER (DIMENSIONLESS) C IER -- ERROR PARAMETER C INFORMATIVE ERRORS C IER=l --- GAS NUMBER DOES NOT EXIST GAS IS ASSUMED TO BE AIR C IER=2 --- TEMPERATURE OUT OF RANGE OF PROPERTY SUBROUTINE C RESTRICTIONS C NGAS -- MUST BE l(AIR) OR 2 (NITROGEN) C T ----- T MUST LIE BETWEEN 150K AND 2100K FOR AIR AND BETWEEN C 83K AND 450K FOR NITROGEN RANGES ARE SPECIFIED WITH ARRAY R C
DIMENSION A(152)B(152)R(32) DATA A36411764E-61423E-399084178E20123 235064914E-62494E-329944985E195930 3 432491E-81239E-415534379E201137 4351618E-6221E-31031408E2084130 DATA B-1005814913800316-4639-09685 2 -999642981521962-4284023930 3 -10469389466-079-5102-0872 4 -10058058 834500239-4636-0265230 DATA R150400210083160450 IER=O IFlaquoNGASGTO) AND(NGASLT3raquo GO TO 1 IER=l NGAS=l
1 1=1 TP=T IF(TLT bullbull O) TP=-T18 IFlaquoTPLTR(lNGASraquo OR (TPGTR(3NGASraquo) IER=2 IF(TPGTR(2NGASraquoI=7 RHO=A(INGAS)TPB(INGAS) XMU=A(I+1NGAS)TPB(I+1NGAS) XK=A(I+2NGAS)TPB(I+2NGAS) CP=A(I+3NGAS)TPB(I+3NGAS) GRB=A(I+4NGAS)TPB(I+4NGAS) PR=A(I+5NGAS)TPB(I+5NGAS) IF(TGT O)RETURN RHO=RHO1602 XMU=XMUl 488 XK=XKl 731 CP=CP4187 GRB=GRB6357 RETURN END
B2 Output
Program FrigWal1 Version 8 August 1991 Programmed by AMClausing
Date Time
05-MAR-92 200227
CASE NUMBER 1 - Fresh Food Walls
Ambient Temperatures IK] Inside 2770 Outside 2940 Characteristic Lengths 1m] Inside 030 Outside 150 Surface Emissivities Inside 095 Outside 095
71
Wall Thickness 0045 m Conductivity 0027 Wm-K Area 242 m2
Q = 209 W ERRQ = 002
hconv [Wm2-K]
Inside 1 98 Outside 130
hrad [Wm2-K] 461 544
Ra
0488E+07 0459E+09
Nu
244 761
Tsur [K]
2783 2927
DeltaT [K] 13 13
RRtot
0077 0075
CASE NUMBER 2 - Fresh Food Door
Ambient Temperatures [K] Inside 2770 Outside 2940 Characteristic Lengths [m] Inside 030 Outside 150 Surface Emissivities Inside 095 Outside 095 Wall Thickness 0040 m Conductivity 0040 Wm-K Area 089 m2
Q = 117 W ERRQ = 001
hconv [Wm2-K]
Inside 218 Outside 144
hrad [Wm2-K] 463 542
Ra
0714E+07 0690E+09
Nu
269 843
Tsur [K]
2789 2921
DeltaT [K]
19 19
RRtot
0114 0113
CASE NUMBER 3 - Freezer Walls
Ambient Temperatures [K] Inside Characteristic Lengths [m] Inside Surface Emissivities Inside
2630 030 095
Wall Thickness 0056 m Conductivity 0027
Outside Outside Outside
2940 150 095
Wm-K Area 110 m2
Q = 14 3 W ERRQ = 003
hconv [Wm2-K]
Inside 226 Outside 143
hrad [Wm2-K] 397 542
Ra
0990E+07 0684E+09
Nu
292 841
Tsur [K]
2651 2921
DeltaT [K]
21 19
RRtot
0067 0061
CASE NUMBER 4 - Freezer Door
Ambient Temperatures [K] Inside 2630 Outside 2940 Characteristic Lengths [m] Inside 030 Outside 150 Surface Emissivities Inside 095 Outside 095 Wall Thickness 0040 m Conductivity 0040 Wm-K Area 034 m2
Q = 81 W ERRQ 002
hconv [Wm2-K]
Inside 259 Outside 1 64
hrad [Wm2-K] 400 538
Ra
0169E+08 0124E+10
Nu
333 967
Tsur [K]
2666 2906
DeltaT [K] 36 34
RRtot
0117 0110
72
__ ___
APPENDIX C TEST REFRIGERATOR DESCRIPTION
The test refrigerator is a White-Westinghouse model RT193MCWO 186 cubic foot
capacity top-mounted unit It is equipped with full automatic defrost The cycle time for
this unit is approximately 50 The unit also has two anti-sweat devices An electric
heater is located in the mullion region to prevent frosting between the freezer and the fresh
food compartments Also a condenser tube runs around the entire outside perimeter of the
unit embedded beneath the steel all flange Figure C1 illustrates these features
~1-- 0787 m (31)__
~ r_----------------------
1581 m
Fig CI Location of Anti-sweat Devices and Overall Dimensions of Test Refrigerator
73
Under test conditions the refrigerator and freezer are filled with milk containers full of
water These containers provide sufficient thennal mass to minimize temperature
fluctuations dming experimental runs Twenty gallons are present in the fresh food
compartment and 6 gallons are in the freezer
Figures C2 through C5 give the detailed dimensions of the fresh food compartment and
the freezer All dimensions are in millimeters and are obtained directly from the unit
Dimensions are estimated to be accurate to within plusmn 3 mm
697
762
1
305
717
Fig C2 Fresh Food Compartment Interior Dimensions
74
1127
Fig C3 Fresh Food Door
75
675
381
Fig C4 Freezer Interior Dimensions
432
Fig CS Freezer Door
76
APPENDIX D DATA ACQUISITION AND CONTROL SYSTEM
Corresponding with the construction of the experimental apparatus was the purchase and
assembly of a data acquisition and control system The system itself was designed to meet
the needs of a variety of experiments and is therefore a very flexible system
The system consists of six DC power supplies a data acquisition chassis a computer a
rack ofdigital relays and a variety of analog and digital inputs and outputs A data
acquisition and control software package orchestrates the interactions between these
components and regulates outgoing signals as well as providing data storage
External signals enter the system through a Keithley 500P data acquisition chassis These
signals consist of voltage and current measurements from the power supplies as well as
thermocouple voltages At present a total of ninety-six thermocouple inputs are available
with an optimal resolution of +0012 degrees C The addition of more thermocouple input
boards could expand the capability to 128 inputs Also special boards can be installed to
allow strain gauge thermistor digital or other standard data acquisition functions The
Keithley chassis can contain a total of nine interface boards and its l~bit AID conversion
allows for very high resolution
The six DC power supplies consist of two Hewlett Packard and four Sorensens with a
combined power of 7560 watts The Sorensens are rated at 0-150 volts at a maximum of
12 amps while the Hewlett Packards produce 0-60 volts at a maximum of 3 amps All of
the power supplies are computer-controlled however the Sorensens may be operated
manually ifdesired Voltage measurements from the power supplies are fed into the
Keithley acquisition chassis and are then routed to the computer A voltage from the
computer is buffered and fed into the control circuits of the power supplies This voltage
completes the loop and controls the output voltage of the power supplies The software is
responsible for reading the output voltage of the power supplies comparing it with the
intended setpoint and adjusting the control voltage as needed This arrangement allows the
user to vary the output voltage of the power supplies from within a program Computershy
controlled safety relays are in place to disconnect the power supplies should they stray too
far from the intended voltage setpoint Fig D1 displays the system
77
Thermocouple and Voltage Inputs
r
Computer Data Acquisition Chasis Intaface
00 Voltage and 1 r Current
Measurement
Computer
I I
Analog Control Signal
Digital Oulput Signals 5 6
Power Supply 4 Relay Rack
Power Supply 3 00000001 Power Supply 2
Buffered Analog100000001 Power Supply 1 Control Signal
1 2 3 4 5 6 - I
I00 00 )0 po po po
Ir Digital Outputs
Analog Outputs
Fig DI Data Acquisition and Control System
78
APPENDIX E EXPERIMENTAL RAW DATA AND PLOTS
E1 Temperature Profile Plots From Fixed Thermocouples
In this appendix the remaining tests for the fixed thennocouple testing presented in Section
41 are provided Figures E1 and E2 give the results from the fresh food compartment
and Figures E3 and E4 give the results from the freezer Notice the outdoor and interior
ambient temperatures are not the same as the two tests presented in Section 41
191
Run 2 ttl ~ i i
middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot
middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot-imiddotmiddot
TWall
middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotlmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot
-
Outdoor Ambient =210 degC Fresh Food Ambient =375 degC
-] _ Door ProfUe i -il- 0 Wall Profile
i 19
$-- - Tdo = 19078 - 001326x
l~l ~~i 189 i i a m
0 i -m-
i 188 middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot
187 ~ middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot 5 = 18989 - O02024x 1
F 186
~bullbullbullbullbullbullbullmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot185 i i
184 0 5 10 15 20 25
x (mm)
Fig E1 Steel Skin Temperature Plot for Fresh Food Compartment (Run 2)
79
191
19
189
a ~
i 188
187
5F
186
185
184 0
Run 3 I --D - Door Profile
middotmiddotmiddotmiddotmiddotmiddotmiddotmiddot-middotmiddotmiddotmiddot~middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotimiddotmiddot-middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddot 0 Wall Profile
i - i - - Tdo =19053 - 001384x or
=c-=r=-~-= 1 11=
~ n - 189S 001998 --t-shy-~~-
5 10 15 20 25
x (mm)
Fig E2 Steel Skin Temperature Plot for Fresh Food Compartment
186
184
182
- ~- 18
178
~ 176
174
172 0
(Run 3)
Run 2 l --0 - Door Profile
middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot~middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotdrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotf 0 Wall Profile - 1- - middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot--m
- - T =18544 - 002398x i - i door rb
~i
i bullbullbulli _ bull imiddot
~ I TWall =18182 - 003542x tmiddotmiddotmiddotmiddot middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotlmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot
~ n~l l
5 10 15 20 25
x (mm)
Fig E3 Steel Skin Temperature Plot for Freezer (Run 2)
80
--a 0
I5F
186
184
182
18
178
176
174
172
Run 3 I --0 - Door Profile
middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotCmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotl 0 ~a1l Profile
ttl __ OJ 1 1 middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotfmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotlmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot -shy - Td = 18411 - 002272x ibullbullbullbullbullbullbull-bullbullbullbullbullbullbullbullbulli
oor ~
rp bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbull bull 11_1
I I middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotimiddotmiddotmiddotmiddot middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotImiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot
~ _l
Outdoor Ambient =208 degc Freezer Ambient = -93 degc
0 5 10 15 20 25
x (mm)
Fig E4 Steel Skin Temperature Plot for Freezer (Run 3)
E2 Thermopile Data Reduction
The data from the thennopile tests consist of an output voltage (mV) measured with a
Keithley multimeter which has a resolution of 1 m V The procedure required to translate
this voltage into a temperature difference follows
1 Read the output voltage in millivolts
2 Detennine the average skin temperature from fixed thennocouple data
3 Use the reference table and the average skin temperature to determine the conversion factor in Vrc
4 Convert to temperature difference as follows
1T = ____o_utpu_t_vo_l_tag-e___
ofjunctions x conversion factor
81
Table EI Thermopile Raw Data
ffOutput fzOutput ff Ave Skin Temp fz Ave Skin Temp mV mV CC CC
Roo wall door wall door wall door wall door
1 0052 0048 0045 0050 189 191 177 183
2 0054 0052 0046 0048 187 189 176 182
3 0056 0053 0046 0051 186 188 175 181 ff Conv Factor fz Conv Factor ff AT fzAT
Ilvrc Ilvre CC CC
Roo wall door wall door wall door wall door
1 40165 40181 40067 40116 026 024 037 041
2 40148 40165 40058 40107 027 026 038 040
3 40140 40157 40050 40099 027 026 038 040
Average Temperature Difference 0267 0377 0253 0403
from Thermocouple Reference Tables Based on the IPTS-68 US Dept of Commerce
E3 Experimental Determination of qwall and qdoor Details
The four heat fluxes are calculated using
-k M (El)q - m Ax
For 05 carbon cold rolled steel km =540 Wm K (312 Btuhr-ft-OF) Also Ax = OOlm (039 in) for all computations
0267degC 2 qwallff = 54 Wm-K 001 m = 14418 Wm
_ 0377 degc _ 2 qwallfz - 54 Wm-K 001 m - 20358 Wm
0~3~ 2 qdoorff =54 Wm-K 001 m =13662 Wm
82
0403degC 2 qdoorfz = 54 Wm-K 001 m = 21762 Wm
Compute the heat transfer rate according to Equation (B2)
q =qA=qhP (B2)
Where A is the cross sectional area of the steel casing that is perpendicular to the direction
of heat flow The area is the product of the steel skin thickness b and the total perimeter of
the compartment opening which is exposed to the room environment P Perimeter
definitions
Pwallff = llm + 076m +llm = 296 m
roJ D Pwallfz =O4lm + 076m + O4lm =l58 m
I ] I ~I Pdoorf( = llm + 076m + llm + 076m = 372 m
Pdoorfz =076m + O4lm + 076m + 041m =234 m
83
qwallff =(14418 Wm2)(65e-4 m)(296 m) =277 W
qwallfz =(20358 Wm2)(65e-4 m)(158 m) =209 W
qdoorff =(13662 Wm2)(65e-4 m)(372 m) =330 W
qdoorfz =(21762 Wm2)(65e-4 m)(234 m) =331 W
E4 Temperature Profile Plots From Mullion Data (Heater oro
The following plots are from the remaining runs for the mullion analysis presented in
Section 45 All data is taken from the exact center of the mullion
131
13 middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot-tmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotjmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotlmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot9middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotlmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot6middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddot T 11 f =12383 + 0019929x iii mu z
129 ~ middotImiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot[middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddota ~
i 128 middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot4middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot-j-middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotfmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotfmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot
127e ~
126 ~~~=H~~-~=HmiddotrI~ ++~11 Room Ambient =2250 degC125
1 1 i Fresh Ambient =515 degC iii i i Freezer Ambient =-603 degC
124
1 10
Fig ES Mullion Temperature Profile Run 2 (Heater Off)
Run 2
2 3 4 5 6 7 8 9
TIC
84
146
145
a 144 ~
i 143
5 ~ 142
141
Run 3 9 0
---r-r--deg-r-ideg-t-9--rshyiii ltD T 11 ff = 15173 - OOI71x mu bull
middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotfmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotImiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot6middotmiddot
1Tmull~fz =14062 + J0158211x JLt 1
Q 1 1 1 middotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1-middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddoti-middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotimiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotoot-middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot-I-bullbullbull~bullbullbullbullbullbullbullbullbullbullbull
iii middotiiimiddot-j Room
1Am~t = 21~1 degC
iii i 1 Fresh Ambient = 563 degC 1 1 1 1 1 Freezer Ambient = -153 degC
14~---+--~----r---+---~---+--~----r---+-
1 2 3 4 5 6 7 8 9
TIC I
Fig E6 Mullion Temperature Profile Run 3 (Heater Off)
127
126
125 a ~
i 124
123 e ~
122
121
12
1
Fig E7
i i CD middotmiddotmiddotmiddot----middotmiddot-r--middot---middotmiddotmiddotmiddotmiddotmiddot-lmiddot--------middotmiddotmiddotmiddotl-middotmiddot---middotmiddotmiddotmiddot---r---middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1middotmiddotmiddotmiddotmiddot---middotmiddot---middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot-r----middot1__ _-
I I I T mulIff = 1321 - 001532x middotmiddotmiddotmiddot------middott--------------tmiddotmiddot----middot----middotmiddot-1------middotmiddotmiddotmiddotmiddotmiddot---jmiddot-----middotmiddotmiddotmiddotmiddotmiddotmiddotmiddot-lmiddotmiddotmiddot---middotmiddotmiddot-----tmiddotmiddotmiddotmiddotmiddot--middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddot-----middotmiddotmiddot6middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot
I cent I I I I -~~~~-ro-Tr-
r-middotmiddotmiddotmiddotrTTr-middotrmiddotrmiddotrmiddot middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddott middotmiddotmiddottmiddotmiddot1middotmiddotbullbullbullbull fmiddotbullbullbullbullbullbullbullmiddot-fbullbullbullbullbullbullbullmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot
II Room Ambil =21~3 degC iii i i Fresh Ambient =551 degc iii i i Freezer Ambient = -681 degC
2 3 4 5 6 7 8 9 10
TIC I
Mullion Temperature Profile Run 4 (Heater Off)
85
10
111
iii i i 11
Fttul5
T mu
=J=~[rr~tl=rI=109
a ~ 108 -t-t-t-i~FFl~i~~
+-0amp_- -+_bullbullbullbullbullbullbullbull+ - bullbullbull 107 11 f ~ 10325 + 0021893x 1 1 1 ji
5 bull Z iii
------~-~-----~---i --L--l ---_l__ ---L-----_shy106 ~
105 -t---i--+-+-+-middot++-I-shyL1LLL Room Ambient = 2177 C104 iii i i Fresh Ambient =448 degC
Freezer Ambient = -644 degC 103
1 2 3 4 5 6 7 8 9 10
TIC
Fig E8 Mullion Temperature Profile Run 5 (Heater Off)
86
34
33 1 1 1 1 1 1 1 1------I---------middotmiddot--+middotmiddotmiddotmiddot------middottmiddot-------middotmiddotmiddotmiddottmiddot----------middotmiddotmiddot---middot---middot----tmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot---middotmiddott--middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot(middotmiddotmiddotmiddotmiddot--
32 11 f =1 2859 ~ OI~X j
Till ff =133013 j - 007124x mu
31
a ~ 30
i 5 ~
29
28
27
26
Tmullfz = 26944 + 014842x
mu t-tr l
25 middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotjmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotjmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotlmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1middot ~ u~ ~it
24 lllti1 ~ i i ~ i
0 Lower Limit
23
0 1 2 3 4 5 6 7 8 9 10
ES Temperature Profile Plots From Mullion Data (Heater On)
The following are the remaining plots from the mullion heater analysis presented in Section
46
TIC I
Fig E9 Mullion Temperature Profile Run 2 (CenterHeater On)
Run 2
T muz
1
87
l----+
29
middotmiddotmiddotgtmiddotmiddoti middot 0 upper Limit 28 Run 1
I
middotmiddotI o
Tmullfz
T muo
LL~4cb 0 Lower Limit27
middot~+ImiddotmiddotmiddotImiddotmiddotmiddottr9middotdJmiddotmiddotmiddotmiddot 26
t T = 29465 008022xmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddot1middotmiddotmiddotmiddotTmiddotmiddotmiddotmiddot[middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1middot mullffa 25~
i 24 =24837+ 013186x middotlmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot+middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotimiddotmiddotmiddotmiddotmiddotmiddotmiddotlmiddotmiddotmiddotmiddotmiddotmiddot iii i i
i _ Jbullbullbullbullbullbullbullbullbullbullbullbullbulli l _l ii 23
e 22~ 21 +I~=tt=l=fit
L~LLL Tm~llff = 23856 005858x20 11 f = 1803 + 02243x z -rmiddotmiddotmiddotmiddot1middot middotmiddot middotmiddot 1middotmiddotmiddotmiddotmiddotTmiddotmiddot middot-rmiddot19
18
0 1 2 3 4 5 6 7 8 9 10
TIC
35
34
33
32
a ~ 31
I ~
30
29
28
27
26
25
24
Fig EI0
---bull---i----bullbullmiddotmiddotmiddotmiddot--~--------middotmiddot-+------ j bullbullbullbull ---bullbullbullbull -i--__---
T 11 f =30063 + OI~x 1 T i 134 196 i
0068 1 38
muz tmiddotmiddot Ilff=middot bull x ltP lt1gt mu
=t=H=t+t=R=t= F-6~I-i~E
Tmullfz = 28103 + 014486x 1middot++middot1middot1
middotmiddotmiddot--middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotimiddotmiddotmiddotmiddotmiddotmiddotmiddot-middotmiddotmiddotmiddotmiddot+middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotbullbullmiddotmiddotmiddot-middotmiddotimiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot~middotmiddot
111111 0 Upper Limit iii iii 0 Lower Limit
0 1 2 3 4 5 6 7 8 9 10
TIC
Mullion Temperature Profile Run 3 (CenterHeater On)
Fig Ell Mullion Temperature Profile Run 1 (LeftHeater On)
88
a
29
28
27
26
25~
i 24
23 e
22~ 21
20
19
18
Fig E12
i l middot middotmiddotmiddotmiddotlmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot+ 0 Upper Limit T 11 f =24474 + 011288x i imu bull z o Lower Limit
=tplusmntplusmnfrplusmnplusmnplusmn ~ I I I I Tmull ff ~ 28793 - o0784x
middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddott----middot------middotmiddotimiddot----middot-middotmiddot--middot-~-middotmiddotmiddot--middot----middotmiddot)middot
=ii=t=1=P-Ltplusmnt iii i T = 25599 - 00689xIfmiddotTTTmiddotmiddotrmiddot ~Ullff iii
T l1f =20552 + 01676x i~~imiddotimiddotmiddot
==~LL L LLLLL i i 1 ~ 1 ~
0 1 2 3 4 5 6 7 8 9 10
TIC I
Mullion Temperature Profile Run 2 (LeftlHeater On)
33 iii i i
-middot--middot(---middotmiddot--middotmiddot--middotmiddot+---middot-middotmiddotmiddotmiddot-middotmiddotmiddot~-middot--middot-------middoti---middot------~ o Upper Limit 32 Run 3
t bullbullbull +
Tm~llfz
T mu
1 1 1 1 1 o Lower Limit ~~31
=2713 ~ 0113~x j11Li30
a T ulff =30658 - 006506x 29~
IktlJ2~Li 28
27 e
26 =l=tt=tmiddotmiddottmiddott+~middot+=t=~ middotmiddot jmiddotjmiddottmiddottmiddotjmiddot T = 28288 - 00603x
iii i mullff 24
25
middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotQmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot+middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot~middotmiddotmiddot middotmiddotmiddotmiddotmiddotmiddotmiddotmiddot~middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot+middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot 11 fz = 2377 ~ 01788x IL11123 i i
22
0 1 2 3 4 5 6 7 8 9 10
TIC I
Fig E13 Mullion Temperature Profile Run 3 (LeftHeater On)
89
31
30
29
ltP ~u
J
1 T
-~Lti=t~-t--t i~+--Ij Tmu1lff =31473 middot005222x 28
1 1 1middot 1 l i l i bullbullbullbullbullbullbull__ bullbullbullbull_ bullbullbullbullbullbullbull~_bullbullbullbullbullbullbullbullbulla bullbullbullbullbullbullbullbullbullbullbull a 27
~ Tm~llfz = 26857 + 01734x _~__+_+II i
26
bullmiddotmiddotbullbullbullmiddotmiddotbullibullbullbullbullbullbullbullbullbullbullbullmiddotmiddotmiddotbullbullbullbullbullbullbullbullmiddotmiddotmiddotmiddot bullbullbullbullbullbullbullbullbull-i-~-i-ii25
JJ$~L-f$9 5 24
~ 23 middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotlmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot+middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot~middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot+middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1-middotmiddot T mllff =25622 bull 002~7X c-bullbullbullbullbullbullbullbullbullbullbullbull+ ~~ 22 rp 1 1 i i 1 1 1
21 = 19464 + 02548 jmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddott Upper Limitmullfz xii 0
4-bullbullbullbullbullbullbullbullbullbullbullbullimiddotmiddotmiddotbullbullbullbullbullbullmiddotf20 i 1 ~ 1
19
0 1 2 3 4 5 6 7 8 9 10
TIC I
Fig E14 Mullion Temperature Profile Run I (RightHeater On)
33 i
middotmiddotmiddotmiddotlaquomiddotmiddotmiddotmiddot------------------------------- c--------middotmiddotmiddot-middot-----------middotmiddotmiddot---middotmiddot--------l-----middot-----I-----32
= 2757 + 017006x ILLJ1
a
31
30
29~
i 28
Run2
TmulIfz
T~ulIfz ~
-~t=ii~Ii~~~~ i
27 middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot9-middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotT~~middotmiddotmiddotmiddotmiddot2s944-middot~middotmiddotO0278~middotmiddote 26~ r~rrTt+rr25
24 2320~ + O~S4x middotmiddotlmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotjmiddot ~ u~ L~t 23 middotmiddotmiddotmiddotmiddotmiddotmiddotmiddot~middotmiddotmiddotmiddotmiddotmiddotmiddot+middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot+middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot+middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotImiddotmiddotj 0 Lower Limit
22
0 1 2 3 4 5 6 7 8 9 10
TIC I
Fig EIS Mullion Temperature Profile Run 2 (RightlHeater On)
90
33 i i ~ _______ _ _~____ __ __-i--bullbullbullbullbullbullbullbull-t------ -- uu__~ ~ --~32
=1268931+ 0~4~14X 111131
30
a 29~
I 28
Run3
Tmullfz
i t+ I T
m
mnplusmn~~27 6 i 1 i 1 +++ T mullff =28912 - 002938x 26~ +middotmiddot++Imiddotjmiddott-25
= 22996 + 02312x 1middotmiddot+ 24
~~~~L lL1 0 ~23 ill 0 22
0 1 2 3 4 5 6 7 8 9 10
TIC
Fig E16 Mullion Temperature Profile Run 3 (RightHeater On)
91
APPENDIX F NUMERICAL SIMULATION EQUATIONS AND CODE
F1 Finite-Difference Equations
Figure Fl is a generic resistor network that is used as a base for all the finite-difference
equations The general fonn is
(Fl)
r----II ij+l
J
i j-l L ______--J
Fig F1 Generic Nodal Resistor Network
This makes it easy to simply plug in the different resistors for the different regions of the
section There are twelve resistors total The following table summarizes the resistors
needed to complete the model
Table F1 Model Resistors
Description Resistance [CIW]
Interior insulation x direction Rl= dx dymiddotkinsmiddotb
92
dyInterior insulation y direction R2= dx-kins-b
dySteel parallel with insulation y direction R3= km-dm-b + kins-(dx -dm)
dxR=Steel parallel with insulation x direction km-dm-b + kins-(dy -dm)
dyRs=Plastic parallel with insulation y direction
kp-dp-b + kins-(dx -dp)
dxPlastic parallel with insulation x direction R6= kp-dp-b + kins-(dy -dp)
heffa- (~- dm) + kinsSteel to exterior x direction R7= 2
heffo-kins-dy-b
heffa- (dY - dm) + kinsSteel to exterior y direction R - 28shyheffo-kins-dx-b
hefti- (dY _dm) + kinsSteel to interior y direction R9= 2
heffi-kins-dx-b
hefti- (~- dp) + kinsPlastic to interior x direction RIO= 2
heffi-kins-dy-b
Rll = hefti- (dJ -dP) + kinsPlastic to interior y direction
heffi-kins-dx-b
93
Steel skinplastic skin interface
2middotkmmiddotdmmiddotkpmiddotdpmiddotdxR12=----------------------~~----------------
2middotkmmiddotdmmiddotkpmiddotdpmiddotbmiddot(dy -dp) + (kpmiddotdp + kmmiddotdm)middotbmiddotdx2
F2 Wall Simulation Source Code
Program FiniteDiff
c This program simulates the conductive heat transfer through the wall section c of the refrigerator near the door gasket using Guass-Siedel iteration c The program allows for flexibility in the geometry and material properties c The program is a steady-state model
cVariable Definitions
c km = conductivity of the outer metal skin (Wm-K) c kins = conductivity of the polyurethane foam insulation (Wm-K) c kp conductivity of the inner plastic skin (Wm-K) c dm = thickness of the metal skin (mm) c dp = thickness of the plastic skin (mm) c b = depth of the section (m) c heffo = effective heat transfer coefficient on outside surfaces (Wm2-K) c heffi = effective heat transfer coefficient on inside surfaces (Wm2-K) c sl width of wall inSUlation (mm) c s2 length of wall section (mm) c s3 seal indentation (mm) c s4 seal width (mm) c s5 distance metal skin travels into cabinet (mm) c s6 distance platic skin travels out of cabinet (mm) c ns = number of nodes corresponding to the s regions above c rs = network resistors (m-eW) c i = integer values of distance along the x axis c j = integer values of distance along the y axis c imax maximum integer value in x direction c jmax maximum integer value in y direction c iter total number of iterations to converge c loop convergence flag c Qinl Heat flux per unit length across the outer boundary (Wm) c Qin2 Heat flux per unit length across the inner boundary (Wm) c Qdif Qinl - Qin2 (Wm) c Qpdif = percent difference between the heat fluxes Qinl and Qin2 c Ti Inside ambient temperature (e) c To = Outside ambient temperature (e)
cDeclare Variables
INTEGER nln2n3n4n5n6ijloopimaxjmaxiter INTEGER clflaglflag2 REAL kmkinskpdmdpdxdyheffoheffi REAL TiToQdifQpdifQinlQin2 REAL sls2s3s4s5s6lenoutlenin REAL rlr2r3r4r5r6r7r8r9rlOrllr12 REAL T(-1lOl-1lOl)bqlDsumlsum2 REAL Qm(lOl)qfluxm(lOl)fluxo(OlOl)fluxi(OlOl)
94
REAL fluxcen(0101)pfluxcen(0101)pfluxo(0101) REAL pfluxi(0101)pmaxdifoneDtolaq2Dqedge1
OPEN (10file-2Dcode(v11)out1position-rewind) OPEN (11file-2Dcode(v11)out2position=rewind)
cTest Parameters
c thermal conductivity of the outer metal skin (Wm K) km-540
c thermal conductivity of the wall insulation (Wm K) kins=0021
c thermal conductivity of the inner plastic skin (Wm K) kp=015
c thickness of the metal skin (mm) dm=065
c thickness of the plastic skin (mm) dp=25
c effective heat transfer coefficient on outside surfaces (Wm2-K) heffo=681
c effective heat transfer coefficient on inside surfaces (Wm2-K) heffi=610
c width of section (mm) sl=450
c length of section (mm) s2=2000
c depth of the section (m) b=10
c inside ambient temperature (C) Ti=95
c outside ambient temperature (C) To=210
c unit conversions dm=dm1000 dp=dp1000 sl=sl1000 s2=s21000
c specify 1-dimensional tolerance (t) oneDtol=30
cMesh Parameters
c specify the following nodal mesh parameters n1=20 n2=80 n3=1 n4=9 n5=10
c various mesh dimensions dx=sln1 dy=s2n2 s3=n3dx s4=n4dx s5=n5dx s6=sl-s5-dx n6=s6dx imax=n1-1 jmax=n2-1
cInitialize temperature matrix
DO 10 j=-1jmax+1 DO 20 i=-1imax+1 T(ij)=Ti
95
20 CONTINUE 10 CONTINUE
DO 30 j=Ojmax T(-Ij)=To
30 CONTINUE
DO 40 i=0n3 T(i-I)=To
40 CONTINUE
DO 50 j=Ojmax T(imax+lj)=Ti
50 CONTINUE
DO 60 i=n3+n4+1imax T(i-I)=Ti
60 CONTINUE
cResistors [m-CW]
c interior insulation x direction rl=dx(kinsdy)
c interior insulation y direction r2=dy(kinsdx)
c metalinsulation y direction r3=dy(kmdm+kins(dx-dm))
c metalinsulation x direction r4=dx(kmdm+kins(dy-dm))
c plasticinsulation y direction r5=dy(kpdp+kins(dx-dp))
c plasticinsulation x direction r6s dx(kpdp+kins(dy-dp))
c metal to exterior x direction r7=(heffolaquodx2)-dm)+kins)(heffokinsdy)
c metal to exterior y direction rB=(heffo laquody2)-dm) +kins)(heffokinsdx)
c metal to interior y direction r9=(heffilaquody2)-dm)+kins)(heffikinsdx)
c plastic to interior x direction rl0=(heffilaquodx2)-dp)+kins)(heffikinsdy)
c plastic to interior y direction rll=(heffilaquody2)-dp)+kins)(heffikinsdx)
c metalplastic interface rI2=(2kmdmkpdpdx)(2kmdmkpdp(dy-dp) + (kpdp+km dm)dxdx)
cxxxxxGuass-Siedel Iterationxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx loop=1 iter=1 DO WHILE (loop eq 1)
c Equations for row 0 i=O j=O CALL sseqn(Tr4r7r3rBijimaxjmax)
DO 70 i=ln3 j=O CALL sseqn(Tr4r4r2rBijimaxjmax)
70 CONTINUE
DO 75 i=n3+1n5-1
96
j=O IF (i le n3+n4) THEN
CALL sseqn(Tr4r4r21e20ijimaxjmax) ELSE
CALL sseqn(Tr4r4r2r9ijimaxjmax) ENDIF
75 CONTINUE
i=n5 j-O IF (i le n3+n4) THEN
CALL sseqn(Tr12r4r21e20ijimaxjmax) ELSE
CALL sseqn(Tr12r4r2r9ijimaxjmax) ENDIF
i=n5+1 j=O IF (i le n3+n4) THEN
CALL sseqn(Tr6r12r21e20ijimaxjmax) ELSE
CALL sseqn(Tr6r12r2rllijimaxjmax) ENDIF
DO 80 i=n5+2imax-l j=O IF (i le n3+n4) then
CALL sseqn(Tr6r6r21Oe20ijimaxjmax) ELSE
CALL sseqn(Tr6r6r2rllijimaxjmax) ENDIF
80 CONTINUE
i=imax j=O CALL sseqn(TrlOr6r5rllijimaxjmax)
c Equations for rows 1 thru jmax-l DO 90 j=ljmax-l
i=O CALL sseqn(Tr1r7r3r3ijimaxjmax)
DO 100 i=1imax-1 CALL sseqn(Tr1r1r2r2ijimaxjmax)
100 CONTINUE
i=imax CALL sseqn(Tr10r1r5r5ijimaxjmax)
90 CONTINUE
c Equations for row jmax j=jmax i=O CALL sseqn(Tr1r710e20r3ijimaxjmax)
DO 110 i=1imax-1 j=jmax CALL sseqn(Tr1r110e20r2ijimaxjmax)
110 CONTINUE
i=imax j=jmax CALL sseqn(Tr10r11Oe20r2ijimaxjmax)
97
c c c
Compute the difference in heat flux crossing the outer boundary and crossing the inner boundaryr ideally the difference should be zero
CALL balance(TToTidxdyn3n4imaxjmaxQdifQpdif c QinlQin2r7r9r8rlOrllb)
c Update loop variables iter-iter+l
c Convergence criterium IF (Qpdif le 20) then
loop-O ENDIF IF (iter eq 10000) THEN loop=O write(lO) Solution did not converge
ENDIF
END DO cxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
cHeat Transfer Calculations
c Compute 10 heat flux through wall CALL oneD (ToTiheffoheffikmkinskpdmdpslqlD)
c Compute the flux thru wall at each node on the c outside and inside walls [Wm2) Also the flux c in the x-direction across the center line of the c section
cl-int(nl2) fluxcen(0)=(1(r4dy))(T(cl0)-T(cl+l0)) fluxo(0)=(1(r7dy))(To-T(00)) fluxi(O)=(l(rlOdy))(T(imaxO)-Ti) DO 112 j=ljmax
fluxcen(j)=(l(rldy))(T(clj)-T(cl+lj)) fluxo(j)=(1(r7dy))(To-T(0j)) flumiddotxi (j) =(1 (rlOdy)) (T (imax j)-Ti)
112 CONTINUE
c Determine the percent of steady-state 10 losses DO 113 j=Ojmax
pfluxcen(j)=(fluxcen(j)qlD) 100 pfluxo(j)=(fluxo(j)qlD)lOO pfluxi(j)=(fluxi(j)qlD)lOO
113 CONTINUE
c Determine where the heat transfer becomes 10 c based on a criticle percentage
flagl=O DO 114 j=O jmax
a=abs(pfluxcen(j)-lOOO) IF (j ne jmax) THEN
IF (a le oneDtol) THEN jstar=j
ENDIF ELSE
IF (a le oneDtol) THEN jstar=j
ELSE flagl=l
ENDIF ENDIF
98
114 CONTINUE
c Determine the edge loss by subtracting the 10 heat c transfer from the heat transfer in the 20 region c across the centerline
flag2=0 IF (flagl eq 0) THEN
q2D=00 DO 115 j=O jstar
q2D-q2D+fluxcen(j) 115 CONTINUE
qedgel=q2D-qlD ELSE
flag2=1 ENDIF
c 10 heat flux along metal skin under the seal into c the cabinet [Wm2J Fluxes for all metal nodes are c computed as well as an average flux The flux from c node (n3+l0) to node (n3+20) is given as qlDm(l) c and so on Assume the temperature of the metal skin c is the temperature of the node at that location
suml=OO sum2=00 DO 119 i=n3+1n3+n4-l
Qm(i)=laquokmdmb)dx)(T(i0)-T(i+10raquo qfluxm(i)=(kmdx)(T(iO)-T(i+lOraquo suml=suml+Qm(i) sum2=sum2+qfluxm(i)
119 CONTINUE pmaxdif=laquoQm(n3+n4-l)-Qm(n3+1raquoQm(n3+lraquo100 qedge2-qfluxm(cl)
cOutput
c Output nodal temperatures to separate file DO 120 j=Ojmax
write(ll) (T(ij)i=Oimax) 120 CONTINUE
c Output flux info to a different file write(10) INPUT PARAMETERS write(lO) write (10 ) Section Dimensions (mm) write(lO) Width sl1000 write (10 ) Length s21000 write(10) Depth blOOO write(10) Steel skin thickness dmlOOO write(lO) Plastic skin thickness dplOOO write(lO) write(10) Mesh Geometry write(10) dx dxlOOO write(lO) dy dylOOO write(lO) Number nodes in x-direction n1 write(lO) Number nodes in y-direction n2 write(lO) Number of steel skin nodes write(lO) (including corner 00) n5+l write(10) Steel nodes under the seal n3+1 ton3+n4 write(10) write(lO) Steel skin conductivity (Wm K) km write(lO) Foam insulation conductivity (Wm K) kins write(lO) Plastic skin conductivity (Wm K) kp write(lO) Outside h (Wm2 K) heffo write(lO) Inside h (Wm2 K) heffi
99
write(10) Outside Temp (C) To write(10) Inside Temp (C) Ti write(10) write (10 ) write(10) write(10) OUPUT PARAMETERS write (10 ) write(10) Number of iterations iter write(10) write(10) Heat Transfer for the Section write(10) OVerall Heat Transfer (W) Qin1 write(10) 10 Heat Flux Thru Wall (Wm2) q1D write (10 ) write(10) Heat Transfer Along Metal Skin Under Seal write(10) node to node qm[Wm2J Qm[WJ DO 135 i=n3+1n3+n4-1
write(10) i i+1 qfluxm(i) Qm(i) 135 CONTINUE
write (10 ) Maximum difference () abs (pmaxdif) write(10) IF (flag2 eq 1) THEN
write(10) The mesh does not extend far enough write(10) in the y-direction to reach 10 heat write(10) transfer for the specified tolerance write(10) ofoneDtol
ELSE write (10 ) Edge loss computed from qe=q2D-q1D qedge1 write (10 ) write(10) Edge loss computed directly from write(10) steel skin ~T at centerline qedge2
ENDIF write (10 ) write (10 ) write(10) Heat fluxes in thru the section write(10) along the centerline [Wm2J write (10 ) write(10) j flux 10 DO 136 j=Ojmax
write(10) j fluxcen(j) pfluxcen(j) 136 CONTINUE
PAUSE STOP END
C
SUBROUTINE sseqn (Trplusirminusirplusjrminusj i jimax jmax)
c This subroutine computes the temperature at node (ij) c given the temperatures of the surrounding nodes and c the resistances leading to these nodes
INTEGER ijimaxjmax REAL T(-1101-1101)rplusirminusirplusjrminusj REAL c1c2c3c4c5
c1=1rplusi c2=1rminusi c3=1rplusj c4=1rminusj c5=c1+c2+c3+c4
T(ij)=(1c5)(c1T(i+1j)+c2T(i-1j)+c3T(ij+1)+c4T(ij-1raquo
100
RETURN END
C
SUBROUTINE balance(TToTidxdyn3n4imaxjmaxQdifQpdif c Qin1Qin2r7r8r9r10r11b)
c This subroutine computes the steady-state heat balance c for the cross-section
INTEGER imaxjmaxijn3n4 REAL T(-1101-1101)TlToQin1Qin2dydx REAL r7r8r9r10r11b
c Compute the heat entering Qin1 [Wj Qin1=00 DO 10 jOjmax
Qin1=Qin1+(b(r7))(To-T(0j)) 10 CONTINUE
DO 20 i=0n3 Qin1=Qin1+(b(r8))(To-T(i0))
20 CONTINUE
c Compute the heat leaving Qin2 [Wj Qin2=00 DO 30 j=Ojmax
Qin2=Qin2+(b(r10))(T(imaxj)-Ti) 30 CONTINUE
DO 40 i=n3+n4+1imax IF (i le nS) then
Qin2=Qin2+(b(r9))(T(i0)-Ti) ELSE
Qin2=Qin2+(b(r11))(T(i0)-Ti) ENDIF
40 CONTINUE
c Compute the absolute difference in heat fluxes [Wj Qdif=abs(Qin2-Qin1)
c Compute the percent difference in the heat transfers [Wj Qpdif=(QdifQin1) 100
RETURN END
C
SUBROUTINE oneD (ToTiheffoheffikmkinskpdmdpslqlD)
c This subroutine compute the one-dimensional c heat flux through the section wall
INTEGER i REAL ToTiheffoheffikmkinskpdmdpsl REAL q1DReqdins
dins=sl-dm~dp
Req=(lheffo) + (dmkm) + (dinskins) +(dpkp)+(lheffi) q1D=(To-Ti)Req
RETURN END
101
F3 Fresh Food Wan Simulation Output
INPUT PARAMETERS
Section Dimensions (mm) Width 4500 Length 2000 Depth 1000 Steel skin thickness 6500 Plastic skin thickness 2500
Mesh Geometry dx 2250 dy 2500 Number nodes in x-direction 20 Number nodes in y-direction 80 Number of steel skin nodes (including corner 00) 11 Steel nodes under the seal 2 to 10
Steel skin conductivity (Wm K) 5400 Foam insulation conductivity (Wm K) 21000E-02 Plastic skin conductivity (Wm K) 1500 Outside h (Wm2 K) 6810 Inside h (Wm2 K) 6100 Outside Temp (C) 2100 Inside Temp (C) 4000
OUPUT PARAMETERS
Number of iterations 5318
10 Heat Flux Thru Wall (Wm2) 9132
Heat Transfer Along Metal Skin Under Seal node to node qm[Wm2] Qm[W]
2 3 1619 1092 3 4 1612 1081 4 5 1660 1019 5 6 1645 1010 6 1 1626 1051 1 8 1601 1041 8 9 1569 1020 9 10 1521 9922
Maximum difference () 9101
Edge loss computed directly from steel skin 1T at centerline 1645
Heat fluxes in thru the section along the centerline [Wm2]
j flux 10 0 4284 4691 1 2246 2459 2 3513 3841 3 4554 4981 4 5311 5881 5 6001 6512 6 6488 1104 1 6868 1520
102
10
20
30
40
50
60
70
8 7169 7850 9 7412 8117
7612 8335 11 7778 8517 12 7918 8670 13 8037 8800 14 8139 8912 15 8227 9008 16 8303 9092 17 8369 9164 18 8428 9228 19 8479 9285
8525 9334 21 8565 9379 22 8601 9418 23 8634 9454 24 8663 9486 25 8690 9515 26 8714 9542 27 8736 9566 28 8756 9588 29 8775 9609
8793 9628 31 8809 9645 32 8824 9662 33 8838 9677 34 8851 9692 35 8863 9705 36 8875 9718 37 8886 9730 38 8896 9742 39 8906 9752
8916 9763 41 8925 9772 42 8933 9782 43 8941 9791 44 8949 9799 45 8956 9807 46 8963 9815 47 8970 9822 48 8976 9829 49 8982 9836
8988 9842 51 8994 9848 52 8999 9854 53 9004 9859 54 9009 9864 55 9013 9869 56 9017 9874 57 9021 9878 58 9025 9883 59 9029 9887
9032 9890 61 9036 9894 62 9039 9897 63 9042 9901 64 9044 9903 65 9047 9906 66 9049 9909 67 9051 9911 68 9053 9913 69 9055 9915
9057 9917 71 9058 9919
103
72 9059 9920 73 9061 9921 74 9062 9922 75 9062 9923 76 9063 9924 77 9063 9924 78 9064 9925 79 9064 9925
j local Qwall [Wl
-1 3215 0 -45410E-02 1 -50708E-02 2 -40940E-02 3 -33836E-02 4 -27620E-02 5 -23180E-02 6 -1 9628E-02 7 -1 6076E-02 8 -1 4300E-02 9 -12524E-02 10 -10748E-02 11 -98601E-03 12 -89722E-03 13 -80842E-03 14 -71962E-03 15 -63081E-03 16 -63082E-03 17 -54202E-03 18 -54202E-03 19 -45322E-03 20 -45322E-03 21 -45322E-03 22 -45321E-03 23 -36442E-03 24 -36442E-03 25 -36442E-03 26 -27562E-03 27 -27561E-03 28 -27561E-03 29 -27561E-03 30 -27561E-03 31 -18682E-03 32 -18682E-03 33 -27561E-03 34 -18682E-03 35 -18682E-03 36 -18681E-03 37 -18682E-03 38 -98018E-04 39 -98018E-04 40 -98018E-04 41 -98018E-04 42 -98018E-04 43 -98018E-04 44 -98018E-04 45 -98018E-04 46 -98018E-04 47 -18682E-03 48 -98018E-04 49 -98018E-04 50 -98018E-04 51 -98018E-04 52 -98018E-04
104
53 -98018E-04 54 -92160E-05 55 -98018E-04 56 -98018E-04 57 -98018E-04 58 -98018E-04 59 -98018E-04 60 -92160E-05 61 -98018E-04 62 -92160E-05 63 -98018E-04 64 -98018E-04 65 -92160E-05 66 -98018E-04 67 -98018E-04 68 -92245E-05 69 -92245E-05 70 -98018E-04 71 -98018E-04 72 -98018E-04 73 -92160E-05 74 -92160E-05 75 -92160E-05 76 -92160E-05 77 -92160E-05 78 -92160E-05 79 -92160E-05
Qwallff [Wm21 = 1442 Qwallff [WI = 2775
Fresh Food Nodal Temperatures
x(mm) v(mm) 1125 3375 5625 7875 10125 12375 14625 16875 19125 21375
125 1761 1755 1748 1741 1734 1727 172 1713 1706 17 375 1768 1753 1738 1723 1707 169 1671 165 1624 1589 625 1775 1752 173 1706 1682 1656 1626 1593 1552 15 875 1781 1751 1722 1691 1659 1625 1587 1544 1494 1434
1125 -1787 1751 1715 1678 1639 1598 1553 1504 1448 1384 1375 1792 1751 1709 1667 1622 1576 1526 1471 1412 1346 1625 1798 1752 1705 1658 1609 1557 1503 1446 1384 ll17 1875 1803 1753 1702 165 1597 1543 1485 1425 1362 1294 2125 1808 1754 17 1645 1589 1531 1471 1409 1344 1276 2375 1813 1756 1699 1641 1582 1522 146 1396 133 1262 2625 1817 1758 1698 1638 1577 1515 1451 1386 132 1251 2875 1822 176 1698 1636 1573 151 1445 1379 1311 1242 3125 1826 1762 1699 1635 1571 1506 144 1373 1304 1235 3375 183 1765 17 1635 1569 1503 1436 1368 1299 1229 3625 1834 1768 1701 1635 1568 1501 1433 1364 1295 1225 3875 1837 177 1703 1635 1568 15 1431 1362 1292 1222 4125 1841 1773 1705 1636 1568 1499 143 136 129 1219 4375 1845 1776 1707 1638 1568 1499 1429 1359 1289 1218 4625 1848 1778 1709 1639 1569 1499 1429 1358 1288 1216 4875 1851 1781 1711 164 157 15 1429 1358 1287 1216 5125 1854 1784 1713 1642 1571 15 1429 1358 1287 1215 5375 1857 1786 1715 1644 1573 1501 143 1358 1287 1215 5625 186 1789 1717 1646 1574 1502 1431 1359 1287 1215
105
5875 1863 1791 1719 1647 1576 1504 1432 136 1288 1215 6125 1866 1794 1721 1649 1577 1505 1433 136 1288 1216 6375 1868 1796 1723 1651 1579 1506 1434 1361 1289 1216 6625 1871 1798 1725 1653 158 1508 1435 1362 129 1217 6875 1873 18 1727 1655 1582 1509 1436 1363 1291 1218 7125 1876 1803 1729 1656 1583 151 1437 1364 1291 1218 7375 1878 1805 1731 1658 1585 1512 1439 1366 1292 1219 7625 188 1807 1733 166 1587 1513 144 1367 1293 122 7875 1882 1809 1735 1661 1588 1515 1441 1368 1294 1221 8125 1884 181 1737 1663 159 1516 1442 1369 1295 1222 8375 1886 1812 1738 1665 1591 1517 1444 137 1296 1223 8625 1888 1814 174 1666 1592 1519 1445 1371 1297 1224 8875 189 1816 1742 1668 1594 152 1446 1372 1298 1225 9125 1892 1817 1743 1669 1595 1521 1447 1373 1299 1225 9375 1893 1819 1745 1671 1596 1522 1448 1374 13 1226 9625 1895 182 1746 1672 1598 1524 1449 1375 1301 1227 9875 1896 1822 1748 1673 1599 1525 145 1376 1302 1228 10125 1898 1823 1749 1674 16 1526 1451 1377 1303 1229 10375 1899 1825 175 1676 1601 1527 1452 1378 1304 123 10625 1901 1826 1751 1677 1602 1528 1453 1379 1305 123 10875 1902 1827 1753 1678 1603 1529 1454 138 1305 1231 11125 1903 1828 1754 1679 1604 153 1455 1381 1306 1232 11375 1904 183 1755 168 1605 1531 1456 1381 1307 1232 11625 1906 1831 1756 1681 1606 1532 1457 1382 1308 1233 11875 1907 1832 1757 1682 1607 1532 1458 1383 1308 1234 12125 1908 1833 1758 1683 1608 1533 1458 1384 1309 1234 12375 1909 1834 1759 1684 1609 1534 1459 1384 131 1235 12625 191 1835 176 1685 161 1535 146 1385 131 1235 12875 1911 1836 1761 1686 1611 1536 1461 1386 1311 1236 13125 1912 1837 1761 1686 1611 1536 1461 1386 1311 1236 13375 1913 1837 1762 1687 1612 1537 1462 1387 1312 1237 13625 1913 1838 1763 1688 1613 1538 1462 1387 1312 1237 13875 1914 1839 1764 1688 1613 1538 1463 1388 1313 1238 14125 1915 184 1764 1689 1614 1539 1464 1388 1313 1238 14375 1916 184 1765 169 1614 1539 1464 1389 1314 1239 14625 1916 1841 1766 169 1615 154 1465 1389 1314 1239 14875 1917 1842 1766 1691 1616 154 1465 139 1315 1239 15125 1918 1842 1767 1691 1616 1541 1465 139 1315 124 15375 1918 1843 1767 1692 1616 1541 1466 1391 1315 124 15625 1919 1843 1768 1692 1617 1542 1466 1391 1316 124 15875 1919 1844 1768 1693 1617 1542 1467 1391 1316 1241 16125 192 1844 1769 1693 1618 1542 1467 1392 1316 1241 16375 192 1844 1769 1694 1618 1543 1467 1392 1317 1241 16625 192 1845 1769 1694 1618 1543 1468 1392 1317 1241 16875 1921 1845 177 1694 1619 1543 1468 1392 1317 1242 17125 1921 1846 177 1694 1619 1544 1468 1393 1317 1242 17375 1921 1846 177 1695 1619 1544 1468 1393 1317 1242 17625 1922 1846 1771 1695 1619 1544 1469 1393 1318 1242 17875 1922 1846 1771 1695 162 1544 1469 1393 1318 1242 18125 1922 1847 1771 1695 162 1544 1469 1393 1318 1243 18375 1922 1847 1771 1696 162 1545 1469 1394 1318 1243 18625 1923 1847 1771 1696 162 1545 1469 1394 1318 1243 18875 1923 1847 1771 1696 162 1545 1469 1394 1318 1243 19125 1923 1847 1772 1696 162 1545 1469 1394 1318 1243 19375 1923 1847 1772 1696 162 1545 1469 1394 1318 1243 19625 1923 1847 1772 1696 1621 1545 1469 1394 1318 1243 19875 1923 1847 1772 1696 1621 1545 1469 1394 1318 1243
106
x(mm) y(mm) 23625 25875 28125 30375 32625 34875 37125 39375 41625 43875
125 1694 1662 1287 1033 8577 7336 6444 5795 5324 4995 375 1536 144 125 1068 9163 7946 6974 6189 5532 4944 625 1431 1334 1203 1066 9379 8252 7275 6423 5657 4935 875 136 127 1164 1051 9408 8374 7423 6548 573 4941
1125 131 1226 1132 1034 9353 8394 7477 6605 5766 4948 1375 1273 1193 1107 1017 9262 836 7478 6618 5779 4952 1625 1245 1168 1086 1002 9162 8302 7449 6607 5776 4951 1875 1223 1148 1069 9886 9064 8236 7408 6583 5764 4948 2125 1205 1132 1055 977 8974 8169 7362 6554 5747 4941 2375 1191 1119 1044 9671 8893 8107 7316 6522 5728 4933 2625 118 1108 1034 9588 8824 8051 7273 6492 5709 4925 2875 1172 11 1026 9518 8764 8002 7235 6464 5691 4916 3125 1164 1093 102 946 8713 796 7201 6439 5674 4908 3375 1159 1087 1015 9412 8671 7924 7172 6417 566 49 3625 1154 1083 101 9373 8636 7894 7148 6399 5647 4894 3875 1151 1079 1007 9341 8608 7869 7128 6383 5636 4888 4125 1148 1077 1004 9316 8585 7849 7111 637 5627 4883 4375 1146 1074 1002 9296 8566 7833 7097 6359 5619 4879 4625 1145 1073 1001 9281 8552 7821 7087 6351 5613 4875 4875 1144 1072 9995 927 8541 7811 7078 6344 5609 4872 5125 1143 1071 9987 9261 8533 7803 7072 6339 5605 487 5375 1143 1071 9982 9256 8528 7798 7067 6335 5602 4868 5625 1143 107 9979 9253 8524 7795 7064 6332 56 4867 5875 1143 107 9978 9251 8522 7793 7062 6331 5599 4866 6125 1143 1071 9979 9251 8522 7792 7061 633 5598 4866 6375 1144 1071 9981 9252 8523 7792 7061 633 5598 4865 6625 1144 1071 9984 9255 8524 7793 7062 633 5598 4865 6875 1145 1072 9988 9258 8526 7795 7063 6331 5598 4865 7125 1145 1072 9993 9261 8529 7797 7065 6332 5599 4866 7375 1146 1073 9998 9265 8533 78 7067 6333 56 4866 7625 1147 1074 10 927 8536 7803 7069 6335 5601 4867 7875 1148 1074 1001 9275 854 7806 7072 6337 5602 4867 8125 1148 1075 1001 928 8545 7809 7074 6339 5603 4868 8375 1149 1076 1002 9285 8549 7813 7077 6341 5605 4869 8625 115 1076 1003 929 8553 7817 708 6343 5606 4869 8875 1151 1077 1003 9295 8558 782 7083 6345 5608 487 9125 1152 1078 1004 93 8562 7824 7086 6347 5609 4871 9375 1152 1078 1004 9306 8567 7828 7089 635 5611 4872 9625 1153 1079 1005 9311 8571 7831 7092 6352 5612 4873 9875 1154 108 1006 9316 8575 7835 7094 6354 5614 4873 10125 1155 108 1006 9321 858 7838 7097 6356 5615 4874 10375 1155 1081 1007 9326 8584 7842 71 6358 5617 4875 10625 1156 1082 1007 933 8588 7845 7103 636 5618 4876 10875 1157 1082 1008 9335 8592 7848 7105 6362 5619 4876 11125 1157 1083 1008 9339 8596 7852 7108 6364 5621 4877 11375 1158 1083 1009 9344 8599 7855 711 6366 5622 4878 11625 1158 1084 1009 9348 8603 7858 7113 6368 5623 4879 11875 1159 1084 101 9352 8606 7861 7115 637 5625 4middot879 12125 116 1085 101 9356 861 7864 7117 6372 5626 488 12375 116 1085 1011 936 8613 7866 712 6373 5627 488 12625 1161 1086 1011 9363 8616 7869 7122 6375 5628 4881 12875 1161 1086 1011 9367 8619 7871 7124 6376 5629 4882 13125 1162 1087 1012 937 8622 7874 7126 6378 563 4882 13375 1162 1087 1012 9373 8625 7876 7128 6379 5631 4883 13625 1162 1087 1013 9376 8627 7878 7129 6381 5632 4883
107
13875 1163 1088 1013 9379 863 788 7131 6382 5633 4884 14125 1163 1088 1013 9382 8632 7882 7133 6383 5634 4884 14375 1164 1089 1013 9384 8634 7884 7134 6384 5634 4885 14625 1164 1089 1014 9387 8636 7886 7136 6385 5635 4885 14875 1164 1089 1014 9389 8638 7888 7137 6386 5636 4885 15125 1165 1089 1014 9392 864 7889 7138 6387 5637 4886 15375 1165 109 1015 9394 8642 7891 714 6388 5637 4886 15625 1165 109 1015 9396 8644 7892 7141 6389 5638 4886 15875 1165 109 1015 9398 8646 7894 7142 639 5638 4887 16125 1166 109 1015 9399 8647 7895 7143 6391 5639 4887 16375 1166 1091 1015 9401 8649 7896 7144 6392 5639 4887 16625 1166 1091 1016 9403 865 7897 7145 6392 564 4888 16875 1166 1091 1016 9404 8651 7898 7146 6393 564 4888 17125 1167 1091 1016 9405 8652 7899 7146 6394 5641 4888 17375 1167 1091 1016 9406 8653 79 7147 6394 5641 4888 17625 1167 1091 1016 9407 8654 7901 7148 6395 5641 4888 17875 1167 1092 1016 9408 8655 7902 7148 6395 5642 4889 18125 1167 1092 1016 9409 8656 7902 7149 6395 5642 4889 18375 1167 1092 1016 941 8656 7903 7149 6396 5642 4889 18625 1167 1092 1016 9411 8657 7903 715 6396 5642 4889 18875 1167 1092 1017 9411 8657 7904 715 6396 5643 4889 19125 1167 1092 1017 9412 8658 7904 715 6396 5643 4889 19375 1167 1092 1017 9412 8658 7904 715 6397 5643 4889 19625 1167 1092 1017 9412 8658 7904 715 6397 5643 4889 19875 1168 1092 1017 9412 8658 7904 715 6397 5643 4889
F4 Freezer Wall Simulation Output
INPUT PARAMETERS
Section Dimensions (mm) Width 5600 Length 2000 Depth 1000 Steel skin thickness 6500 Plastic skin thickness 2500
Mesh Geometry dx 2800 dy 2500 Number nodes in x-direction 20 Number nodes in y-direction 80 Number of steel skin nodes (including corner 00) 9 Steel nodes under the seal 2 to 8
Steel skin conductivity (Wm K) 5400 Foam insulation conductivity (Wm K) 27000E-02 Plastic skin conductivity (Wm K) 1500 Outside h (Wm2 K) 6870 Inside h (Wm2 K) 6410 Outside Temp (C) 2100 Inside Temp (C) -1000
OUPUT PARAMETERS
108
Number of iterations 5409
Heat Transfer for the Section OVerall Heat Transfer (WI 4518 10 Heat Flux Thru Wall (Wm21 1362
Heat Transfer Along Metal Skin Under Seal node to node
2 3 3 4 4 5 5 6 6 7 7 8
Maximum difference
qm[Wm2) Om(W) 3026 1967 3008 1955 2981 1938 2944 1914 2892 1880 2820 1833
(1 6799
Edge loss computed from qe=q20-q1D 1760
Edge loss compusteel skin AT
ted directly from at centerline 2981
Heat fluxes in thru the section along the centerline [Wm2)
j flux UO 0 7762 5698 1 3711 2724 2 5678 41 68 3 7275 5341 4 8508 6246 5 9437 6927 6 1013 7438 7 1066 7823 8 1106 8117 9 1137 8347 10 1162 8529 11 1182 8678 12 1199 8801 13 1213 8904 14 1225 8992 15 1235 9068 16 1244 9135 17 1252 9193 18 1259 9245 19 1266 9291 20 1271 9333 21 1276 9370 22 1281 9405 23 1285 9436 24 1289 9464 25 1293 9491 26 1296 9515 27 1299 9538 28 1302 9559 29 1305 9578 30 1307 9596 31 1310 9614 32 1312 9630 33 1314 9645 34 1316 9659 35 1318 9673 36 1319 9685 37 1321 9697
109
38 1323 9709 39 1324 9720 40 1325 9730 41 1327 9740 42 1328 9749 43 1329 9758 44 1330 9767 45 1332 9775 46 1333 9783 47 1334 97bull 90 48 1335 9797 49 1336 9804 50 1336 9810 51 1337 9816 52 1338 9822 53 1339 9828 54 1340 9833 55 1340 9838 56 1341 9843 57 1341 9847 58 1342 9852 59 1343 9856 60 1343 9859 61 1344 9863 62 1344 9866 63 1344 9870 64 1345 9873 65 1345 9875 66 1346 9878 67 1346 9880 68 1346 9882 69 1347 9884 70 1347 9886 71 1347 9888
72 1347 9889 73 1347 9891 74 1347 9892 75 1348 9893 76 1348 9893 77 1348 9894 78 1348 9894 79 1348 9894
j local Qwall [WI
-1 3067 0 -36774E-02 1 -40214E-02 2 -32314E-02 3 -25994E-02 4 -20859E-02 5 -16909E-02 6 -14144E-02 7 -12169E-02 8 -10589E-02 9 -90092E-03 10 -78242E-03 11 -70342E-03 12 -66392E-03 13 -58492E-03 14 -54542E-03 15 -50592E-03 16 -46642E-03 17 -42692E-03 18 -42692E-03
110
19 -38742E-03 20 -34792E-03 21 -30842E-03 22 -30842E-03 23 -30842E-03 24 -26892E-03 25 -26892E-03 26 -22942E-03 27 -22942E-03 28 -22942E-03 29 -22942E-03 30 -18992E-03 31 -1 8992E-03 32 -18992E-03 33 -18992E-03 34 -1 8992E-03 35 -1 5042E-03 36 -1 8992E-03 37 -15042E-03 38 -1 5042E-03 39 -11092E-03 40 -11092E-03 41 -11092E-03 42 -11092E-03 43 -11092E-03 44 -11092E-03 45 -11092E-03 46 -11092E-03 47 -71417E-04 48 -11092E-03 49 -71421E-04 50 -11092E-03 51 -71417E-04 52 -11092E-03 53 -71417E-04 54 -71421E-04 55 -71421E-04 56 -71417E-04 57 -31916E-04 58 -31920E-04 59 -31916E-04 60 -31916E-04 61 -71417E-04 62 -11421E-04 63 -71421E-04 64 -31920E-04 65 -31920E-04 66 -71417E-04 67 -31916E-04 68 -71417E-04 69 -31920E-04 70 -71421E-04 71 -31920E-04 72 -31920E-04 73 -71417E-04 74 -31916E-04 75 -31916E-04 76 -31916E-04 77 -31916E-04 78 -71417E-04 79 -71417E-04
Qwallfz [Wm2J = 2895 Qwallfz [WJ = 2721
111
Freezer Wan Nodal Temperatures
x(mm) y1mm 14 42 70 98 126 154 182 210 238 266
125 1507 1492 1477 1461 1445 143 1415 14 1385 1338 375 1519 1489 1458 1426 1392 1353 1307 1247 1154 972 625 1531 1486 1441 1393 1341 1282 1212 1121 9925 7989 875 1542 1484 1425 1363 1296 1221 1132 1023 8837 7014
1125 1553 1483 1412 1338 1258 117 1069 9508 809 6396 1375 1563 1483 1401 1317 1227 1129 102 8969 7563 5974 1625 1572 1483 1393 13 1202 1097 9824 8568 7184 5673 1875 1582 1485 1387 1287 1182 1072 9537 8269 6906 5452 2125 1591 1488 1384 1277 1167 1053 9321 8046 67 5288 2375 1599 1491 1382 1271 1157 1039 916 7881 6547 5164 2625 1608 1495 1381 1266 1149 1028 9041 7758 6433 5071 2875 1616 1499 1382 1264 1144 1021 8955 7668 6349 5002 3125 1623 1504 1384 1263 114 1016 8895 7604 6288 495 3375 1631 1509 1386 1263 1139 1013 8854 7559 6245 4913 3625 1638 1514 1389 1264 1138 1011 8829 753 6216 4888 3875 1645 1519 1393 1266 1139 1011 8816 7513 6198 4872 4125 1652 1524 1396 1269 114 1011 8813 7505 6188 4863 4375 1658 1529 14 1271 1142 1012 8817 7505 6185 486 4625 1664 1534 1405 1275 1144 1014 8826 751 6188 4861 4875 167 1539 1409 1278 1147 1016 884 752 6195 4867 5125 1676 1544 1413 1281 115 1018 8858 7533 6206 4875 5375 1682 1549 1417 1285 1153 102 8877 755 6219 4886 5625 1687 1554 1421 1289 1156 1023 8899 7568 6235 4899 5875 1692 1559 1425 1292 1159 1026 8923 7588 6252 4914 6125 1698 1563 143 1296 1162 1028 8947 7609 627 493 6375 1702 1568 1434 1299 1165 1031 8972 763 6289 4946 6625 1707 1572 1438 1303 1169 1034 8997 7653 6308 4964 6875 1712 1576 1441 1306 1172 1037 9022 7675 6329 4982 7125 1716 158 1445 131 1175 104 9048 7698 6349 5 7375 172 1584 1449 1313 1178 1043 9073 7721 6369 5018 7625 1724 1588 1452 1317 1181 1045 9098 7744 639 5036 7875 1728 1592 1456 132 1184 1048 9123 7766 641 5054 8125 1732 1595 1459 1323 1187 1051 9147 7788 643 5072 8375 1736 1599 1462 1326 1189 1053 917 781 645 509 8625 1739 1602 1465 1329 1192 1056 9194 7831 6469 5108 8875 1743 1605 1468 1332 1195 1058 9216 7852 6488 5125 9125 1746 1609 1471 1334 1197 1061 9238 7872 6507 5142 9375 1749 1612 1474 1337 12 1063 926 7892 6525 5158 9625 1752 1615 1477 134 1202 1065 9281 7911 6542 5174 9875 1755 1617 148 1342 1205 1067 9301 793 656 519 10125 1758 162 1482 1344 1207 1069 9321 7948 6576 5205 10375 1761 1623 1485 1347 1209 1071 934 7966 6593 522 10625 1763 1625 1487 1349 1211 1073 9358 7983 6608 5234 10875 1766 1627 1489 1351 1213 1075 9376 7999 6623 5248 11125 1768 163 1491 1353 1215 1077 9393 8015 6638 5262 11375 1771 1632 1494 1355 1217 1079 941 8031 6652 5275 11625 1773 1634 1496 1357 1219 1081 9426 8045 6666 5287 11875 1775 1636 1498 1359 1221 1082 9441 806 6679 53 12125 1777 1638 1499 1361 1222 1084 9456 8073 6692 5311 12375 1779 164 1501 1362 1224 1085 947 8087 6704 5322 12625 1781 1642 1503 1364 1225 1087 9483 8099 6716 5333 12875 1783 1644 1505 1366 1227 1088 9496 8111 6727 5344
112
13125 1784 1645 1506 1367 1228 109 9509 8123 6738 5353 13375 1786 1647 1508 1369 123 1091 9521 8134 6748 5363 13625 1788 1648 1509 137 1231 1092 9532 8145 6758 5372 13875 1789 165 151 1371 1232 1093 9543 8155 6768 5381 14125 1791 1651 1512 1373 1233 1094 9554 8165 6777 5389 14375 1792 1652 1513 1374 1235 1095 9564 8174 6785 5397 14625 1793 1654 1514 1375 1236 1096 9573 8183 6793 5404 14875 1794 1655 1515 1376 1237 1097 9582 8191 6801 5412 15125 1796 1656 1516 1377 1238 1098 959 8199 6808 5418 15375 1797 1657 1517 1378 1238 1099 9598 8206 6815 5425 15625 1798 1658 1518 1379 1239 11 9606 8213 6822 5431 15875 1799 1659 1519 138 124 1101 9613 822 6828 5436 16125 18 166 152 138 1241 1101 9619 8226 6834 5442 16375 18 1661 1521 1381 1242 1102 9626 8232 6839 5446 16625 1801 1661 1521 1382 1242 1103 9631 8237 6844 5451 16875 1802 1662 1522 1382 1243 1103 9637 8242 6848 5455 17125 1803 1663 1523 1383 1243 1104 9642 8247 6853 5459 17375 1803 1663 1523 1384 1244 1104 9646 8251 6857 5463 17625 1804 1664 1524 1384 1244 1105 965 8255 686 5466 17875 1804 1664 1524 1384 1245 1105 9654 8258 6863 5469 18125 1805 1665 1525 1385 1245 1105 9657 8261 6866 5471 18375 1805 1665 1525 1385 1245 1106 966 8264 6869 5474 18625 1805 1665 1525 1385 1246 1106 9662 8266 6871 5476 18875 1806 1666 1526 1386 1246 1106 9664 8268 6872 5477 19125 1806 1666 1526 1386 1246 1106 9666 827 6874 5479 19375 1806 1666 1526 1386 1246 1106 9667 8271 6875 548 19625 1806 1666 1526 1386 1246 1107 9668 8271 6876 548 19875 1806 1666 1526 1386 1246 1107 9668 8272 6876 5481
x(mm) v(mm) 294 322 350 378 406 434 462 490 518 546
125 549 054 -27 -5 -624 -727 -8 -85 -89 -92 375 548 171 -12 -338 -5 -624 -719 -795 -858 -914 625 51 22 -032 -24 -408 -543 -654 -748 -83 -907 875 474 238 0182 -175 -34 -482 -603 -71 -807 -898
1125 445 243 048 -132 -293 -436 -564 -68 -787 -89 1375 423 243 0653 -103 -259 -402 -534 -656 -772 -883 1625 406 24 0752 -084 -236 -378 -511 -638 -759 -877 1875 393 237 0808 -071 -219 -36 -495 -624 -749 -871 2125 382 233 0837 -063 -208 -348 -483 -614 -741 -867 2375 374 23 085 -058 -2 -339 -474 -606 -735 -863 2625 368 227 0855 -055 -195 -332 -467 -6 -731 -86 2875 363 225 0855 -053 -191 -328 -462 -596 -728 -858 3125 36 223 0853 -052 -189 -324 -459 -593 -725 -856 3375 357 221 0851 -051 -187 -322 -457 -59 -723 -855 3625 355 22 0849 -05 -186 -32 -455 -588 -722 -854 3875 354 219 0849 -049 -185 -319 -453 -587 -72 -853 4125 353 219 0849 -049 -184 -318 -452 -586 -72 -853 4375 353 219 0852 -049 -183 -317 -451 -585 -719 -852 4625 353 219 0855 -048 -183 -317 -451 -584 -718 middot852 4875 353 22 0861 -047 -182 -316 -45 -584 -718 -852 5125 354 22 0867 -047 -181 -315 -449 -584 -717 -851 5375 355 221 0875 -046 -181 -315 -449 -583 -717 -851 5625 356 222 0884 -045 -18 -314 -448 -582 -717 -851 5875 358 223 0894 -044 -179 -313 -448 -582 -716 -851 6125 359 225 0904 -043 -178 -313 -447 -582 -716 -851 6375 36 226 0915 -043 -177 -312 -447 -581 -716 -85
113
6625 362 227 0927 -042 -177 -311 -446 -581 -716 -85 6875 363 229 0939 -04 -176 -311 -445 -58 -715 -85 7125 365 23 0951 -039 -175 -31 -445 -58 -715 -85 7375 367 232 0964 -038 -174 -309 -444 -579 -715 -85 7625 368 233 0976 -037 -173 -308 -444 -579 -714 -85 7875 37 234 0989 -036 -172 -308 -443 -578 -714 -849 8125 371 236 1 -035 -171 -307 -442 -578 -714 -849 8375 373 237 101 -034 -17 -306 -442 -578 -713 -849 8625 375 239 103 -033 -169 -305 -441 -577 -713 -849 8875 376 24 104 -032 -168 -305 -441 -577 -713 -849 9125 378 241 105 -031 -168 -304 -44 -576 -712 -849 9375 379 243 106 -03 -167 -303 -439 -576 -712 -848 9625 381 244 107 -029 -166 -302 -439 -575 -712 -848 9875 382 245 109 -028 -165 -302 -438 -575 -712 -848 10125 384 246 11 -027 -164 -301 -438 -574 -711 -848 10375 385 248 111 -026 -163 -3 -437 -574 -711 -848 10625 386 249 112 -025 -163 -3 -437 -574 -711 -848 10875 387 25 113 -024 -162 -299 -436 -573 -711shy -848 11125 389 251 114 -023 -161 -298 -436 -573 -71 -848 11375 39 252 115 -022 -16 -298 -435 -573 -71 -847 11625 391 253 115 -022 -16 -297 -435 -572 -71 -847 11875 392 254 116 -021 -159 -297 -434 -572 -709 -847 12125 393 255 117 -02 -158 -296 -434 -572 -709 -847 12375 394 256 118 -019 -158 -296 -434 -571 -709 -847 12625 395 257 119 -019 -157 -295 -433 -571 -709 -847 12875 396 258 12 -018 -157 -295 -433 -571 -709 -847 13125 397 259 12 -017 -156 -294 -432 -57 -709 -847 13375 398 259 121 -017 -155 -294 -432 -57 -708 -847 13625 399 26 122 -016 -155 -293 -432 -57 -708 -846 13875 399 261 122 -016 -154 -293 -431 -57 -708 -846 14125 4 262 123 -015 -154 -292 -431 -569 -708 -846 14375 401 262 124 -015 -154 -292 -431 -569 -708 -846 14625 402 263 124 -014 -153 -292 -43 -569 -707 -846 14875 402 263 125 -014 -153 -291 -43 -569 -707 -846 15125 403 264 125 -013 -152 -291 -43 -569 -707 -846 15375 403 264 126 -013 -152 -291 -43 -568 -707 -846 15625 404 265 126 -012 -152 -291 -429 -568 -707 -846 15875 405 265 126 -012 -151 -29 -429 -568 -707 -846 16125 405 266 127 -012 -151 -29 -429 -568 -707 -846 16375 405 266 127 -011 -151 -29 -429 -568 -707 -846 16625 406 267 128 -011 -151 -29 -429 -568 -707 -846 16875 406 267 128 -011 -15 -289 -428 -568 -707 -845 17125 407 267 128 -01 -15 -289 -428 -567 -706 -845 17375 407 268 128 -01 -15 -289 -428 -567 -706 -845 17625 407 268 129 -01 -15 -289 -428 -567 -706 -845 17875 407 268 129 -01 -15 -289 -428 -567 -706 -845 18125 408 268 129 -01 -15 -289 -428 -567 -706 -845 18375 408 269 129 -01 -149 -289 -428 -567 -706 -845 18625 408 269 129 -001 -149 -288 -428 -567 -706 -845 18875 408 269 129 -001 -149 -288 -428 -567 -706 -845 19125 408 269 13 -001 -149 -288 -428 -567 -706 -845 19375 409 269 13 -001 -149 -288 -428 -567 -706 -845 19625 409 269 13 -001 -149 -288 -428 -567 -706 -845 19875 409 269 13 -001 -15 -288 -428 -567 -706 -845
114
FS Fresh Food Wan Simulation Output Including Anti-sweat Condenser Tube
INPUT PARAMETERS
Section Dimensions (mm) Hidth 4500 Length 2000 Depth 2960 Steel skin thickness 6500 Plastic skin thickness 2500
Mesh Geometry dx 2250 dy 2500 Number nodes in x-direction 20 Number nodes in y-direction 80 Number of steel skin nodes (including corner 00) 11 Steel nodes under the seal 2 to 10 Tube located at node 6
Steel skin conductivity (Him K) 5400 Foam insulation conductivity (Him K) 27000E-02 Plastic skin conductivity (Him K) 1500 Outside h (Hm2 K) 6870 Inside h (Hm2 K) 6700 Outside Temp (C) 2100 Inside Temp (C) 4000
OUPUT PARAMETERS
Number of iterations 602
10 Heat Flux Thru Hall (Hm2) 9132
Heat Transfer Along Metal Skin Under Seal node to node qm[Hm21 Qm[HI
2 3 -15052E+04 -2896 3 4 -15125E+04 -2910 4 5 -15198E+04 -2924 5 6 -15274E+04 -2939 6 7 3996 7688 7 8 3898 7500 8 9 3790 7292 9 10 3662 7045
Maximum difference () 1243
j qleft [HI qright [HI -1 -2957 7832 0 -92065E-02 -38838E-02 1 -77348E-02 -48044E-02 2 -51596E-02 -30284E-02 3 -32948E-02 -15188E-02 4 -1 9628E-02 -54201E-03 5 -98600E-03 16837E-03 6 -36442E-03 70ll8E-03 7 79586E-04 96757E-03 8 43478E-03 11452E-02 9 70118E-03 12340E-02 10 87877E-03 12340E-02
115
11 87879E-03 13228E-02 12 10564E-02 12340E-02 13 10564E-02 11452E-02 14 96759E-03 11452E-02 15 87877E-03 10564E-02 16 87879E-03 87877E-03 17 78999E-03 87877E-03 18 61238E-03 78999E-03 19 61240E-03 61237E-03 20 52359E-03 52358E-03 21 34598E-03 34598E-03 22 25719E-03 25717E-03 23 16838E-03 16839E-03 24 79586E-04 25 -98018E-04 26 -18681E-03 27 -27561E-03 28 -36442E-03 29 -54202E-03 30 -54202E-03 31 -7 1962E-03 32 -80842E-03 33 -8 9721E-03 34 -98602E-03 35 -10748E-02 36 -11636E-02 37 -12524E-02 38 -1 3412E-02 39 -1 4300E-02 40 -15188E-02 41 -1 5188E-02 42 -1 6076E-02 43 -16964E-02 44 -17852E-02 45 -1 7852E-02 46 -1 8740E-02 47 -19628E-02 48 -19628E-02 49 -19628E-02 50 -20516E-02 51 -21404E-02 52 -22292E-02 53 -22292E-02 54 -23180E-02 55 -23180E-02 56 -23180E-02 57 -24068E-02
79578E-04 -98018E-04 -1 8682E-03 -27561E-03 -45322E-03 -54202E-03 -71962E-03 -71962E-03 -8 9722E-03 -8 9722E-03 -10748E-02 -11636E-02 -12524E-02 -13412E-02 -14300E-02 -1 5188E-02 -16076E-02 -16964E-02 -16964E-02 -17852E-02 -18740E-02 -19628E-02 -20516E-02 -20516E-02 -21404E-02 -22292E-02 -22470E-02 -22381E-02 -22647E-02 -23358E-02 -23447E-02 -23802E-02 -24512E-02 -24690E-02
58 -23979E-02 -25223E-02 59 -24423E-02 60 -24246E-02 61 -24423E-02 62 -24779E-02 63 -25400E-02 64 -25400E-02 65 -25667E-02 66 -26199E-02 67 -26022E-02 68 -26111E-02 69 -26377E-02 70 -26022E-02 71 -26732E-02 72 -26821E-02 73 -26199E-02 74 -26643E-02
-25489E-02 -25755E-02 -25933E-02 -2 6199E-02 -26466E-02 -26643E-02 -26821E-02 -26910E-02 -27087E-02 -27265E-02 -27354E-02 -27443E-02 -27531E-02 -27620E-02 -27620E-02 -27709E-02
116
75 -26377E-02 -27709E-02 76 -26377E-02 -27709E-02 77 -26555E-02 -27709E-02 78 -26910E-02 -27620E-02 79 -26555E-02 -27620E-02
Qleft [ii] -3079 Qright [ii] 6756 Percent entering cabinet 1800
Fresh Food Nodal Temperatures (Condenser Tube)
x(mm) y(mm) 1125 3375 5625 7875 10125 12375 14625 16875 19125 21375
19875 126 1206 1154 1104 1055 1007 9608 9158 872 8294 19625 1259 1205 1153 1103 1054 1006 9602 9152 8715 8289 19375 1259 1205 1153 1102 1053 1006 9598 9149 8711 8285 19125 1259 1205 1153 1102 1053 1006 9596 9147 871 8284 18875 1259 1205 1153 1102 1053 1006 9596 9147 871 8284 18625 1259 1205 1153 1103 1054 1006 9599 915 8712 8286 18375 126 1206 1154 1103 1054 1007 9604 9154 8716 829 18125 1261 1207 1155 1104 1055 1007 9611 9161 8722 8295 17875 1263 1209 1156 1105 1056 1008 962 9169 873 8302 17625 1264 121 1158 1107 1058 101 9632 918 874 8311 17375 1266 1212 116 1109 1059 1011 9646 9193 8752 8322 17125 1269 1215 1162 1111 1061 1013 9663 9209 8766 8335 16875 1272 1217 1164 1113 1063 1015 9682 9226 8783 835 16625 1275 122 1167 1116 1066 1017 9704 9246 8801 8367 16375 1279 1224 117 1119 1069 102 9728 9269 8822 8386 16125 1282 1227 1174 1122 1072 1023 9755 9294 8845 8407 15875 1287 1231 1178 1126 1075 1026 9785 9322 887 843 15625 1292 1236 1182 113 1079 103 9818 9352 8898 8456 15375 1297 1241 1187 1134 1083 1034 9854 9385 8929 8484 15125 1302 1246 1192 1139 1088 1038 9892 9421 8962 8514 14875 1308 1252 1197 1144 1092 1042 9934 946 8998 8547 14625 1315 1258 1203 1149 1097 1047 9979 9502 9037 8583 14375 1322 1265 1209 1155 1103 1052 1003 9547 9078 8621 14125 1329 1272 1216 1162 1109 1058 1008 9595 9123 8662 13875 1337 1279 1223 1168 1115 1064 1014 9647 9171 8706 13625 1346 1287 1231 1176 1122 107 102 9703 9222 8753 13375 1355 1296 1239 1183 1129 1077 1026 9762 9277 8803 13125 1364 1305 1247 1191 1137 1084 1033 9824 9335 8856 12875 1374 1314 1256 12 1145 1092 104 9891 9396 8913 12625 1385 1325 1266 1209 1154 11 1047 9962 9462 8973 12375 1396 1335 1276 1219 1163 1109 1055 1004 9531 9037 12125 1408 1347 1287 1229 1173 1118 1064 1012 9605 9105 11875 1421 1359 1299 124 1183 1127 1073 102 9683 9176 11625 1434 1371 1311 1251 1194 1137 1082 1029 9765 9252 11375 1448 1385 1323 1263 1205 1148 1092 1038 9851 9332 11125 1462 1399 1336 1276 1217 1159 1103 1048 9943 9416 10875 1478 1413 135 1289 1229 1171 1114 1058 1004 9505 10625 1494 1429 1365 1303 1243 1184 1126 1069 1014 9598 10375 1511 1445 138 1318 1257 1197 1138 1081 1025 9696 10125 1528 1462 1397 1333 1271 121 1151 1093 1036 98 9875 1547 1479 1413 1349 1286 1225 1165 1106 1048 9908 9625 1566 1498 1431 1366 1302 124 1179 1119 106 1002
117
9375 1586 1517 145 1384 1319 1256 1194 1133 1073 1014 9125 1607 1537 1469 1402 1336 1272 1209 1147 1087 1027 8875 1629 1558 1489 1421 1355 129 1226 1163 1101 104 8625 1652 158 151 1441 1374 1308 1243 1179 1116 1054 8375 1676 1603 1532 1462 1394 1327 1261 1195 1131 1068 8125 17 1627 1555 1484 1415 1346 1279 1213 1148 1084 7875 1726 1652 1579 1507 1436 1367 1299 1231 1165 11 7625 1753 1678 1604 1531 1459 1389 1319 1251 1183 1116 7375 1781 1704 1629 1556 1483 1411 1341 1271 1202 1134 7125 1809 1732 1656 1581 1508 1435 1363 1292 1222 1152 6875 1839 1761 1684 1608 1533 146 1387 1314 1243 1172 6625 187 1791 1713 1636 156 1485 1411 1337 1264 1192 6375 1903 1823 1744 1666 1589 1512 1437 1362 1287 1214 6125 1936 1855 1775 1696 1618 1541 1464 1387 1312 1236 5875 197 1889 1808 1728 1649 157 1492 1414 1337 126 5625 2006 1923 1842 1761 1681 1601 1522 1443 1364 1285 5375 2043 196 1877 1795 1714 1633 1553 1473 1392 1312 5125 2081 1997 1914 1832 1749 1668 1586 1504 1422 134 4875 212 2036 1952 1869 1786 1704 1621 1538 1454 137 4625 2161 2076 1992 1909 1825 1741 1658 1573 1488 1403 4375 2203 2118 2034 195 1866 1782 1697 1611 1525 1437 4125 2246 2161 2077 1993 1909 1824 1738 1652 1564 1474 3875 229 2206 2123 2039 1955 1869 1783 1695 1606 1515 3625 2336 2253 217 2087 2003 1918 1831 1742 1651 1558 3375 2383 2302 222 2138 2055 197 1882 1793 1701 1606 3125 2432 2353 2273 2192 211 2026 1938 1848 1755 1658 2875 2482 2405 2328 225 217 2086 20 1909 1815 1715 2625 2533 2461 2387 2312 2234 2153 2067 1977 1881 178 2375 2586 2518 2449 2378 2304 2226 2142 2052 1955 1851 2125 264 2579 2516 2451 2381 2306 2225 2136 2039 1933 1875 2696 2642 2587 2529 2466 2396 2319 2232 2134 2026 1625 2753 2709 2664 2614 256 2497 2425 2341 2244 2133 1375 2811 278 2746 2708 2664 2611 2546 2468 2373 226 1125 2871 2854 2835 2811 278 2739 2685 2615 2524 2411 875 2932 2932 293 2923 2909 2885 2846 2787 2706 2595 625 2995 3014 3031 3045 3052 3049 3031 2989 2922 2824 375 3058 3098 3138 3175 3208 3234 3245 3223 3179 3109 125 3124 3185 3247 331 3373 3436 35 3483 3467 3451
x(mm) y(mm) 23625 25875 28125 30375 32625 34875 37125 39375 41625 43875
19875 7877 747 7071 6679 6294 5915 554 5168 4799 4432 19625 7872 7466 7067 6676 6291 5912 5538 5166 4798 4431 19375 7869 7463 7065 6674 6289 591 5536 5165 4797 443 19125 7868 7462 7063 6673 6288 591 5535 5165 4797 443 18875 7868 7462 7063 6673 6288 591 5535 5165 4796 443 18625 787 7463 7065 6674 6289 591 5536 5165 4797 443 18375 7873 7466 7067 6676 6291 5912 5537 5166 4797 443 18125 7878 747 7071 6679 6294 5914 5539 5167 4798 4431 17875 7884 7476 7076 6684 6298 5917 5542 5169 4799 4431 17625 7893 7483 7083 6689 6303 5921 5545 5172 4801 4432 17375 7903 7492 7091 6696 6309 5926 5549 5175 4803 4433 17125 7914 7503 71 6704 6316 5932 5553 5178 4806 4435 16875 7928 7515 7111 6714 6324 5939 5559 5182 4809 4436 16625 7943 7529 7123 6725 6333 5947 5565 5187 4812 4438 16375 796 7544 7137 6737 6343 5955 5572 5192 4815 444 16125 7979 7561 7152 675 6355 5965 558 5198 4819 4442
118
15875 8001 7581 7169 6765 6368 5976 5589 5205 4824 4445 15625 8024 7601 7188 6781 6382 5987 5598 5212 4829 4447 15375 8049 7624 7208 6799 6397 6 5608 522 4834 445 15125 8077 7649 723 6819 6414 6014 562 5229 484 4453 14875 8107 7676 7254 684 6432 603 5632 5238 4847 4457 14625 8139 7705 728 6862 6451 6046 5645 5248 4854 4461 14375 8174 7737 7308 6887 6472 6064 566 5259 4861 4465 14125 8211 777 7338 6913 6495 6083 5675 5271 4869 4469 13875 8251 7806 737 6941 6519 6103 5691 5283 4878 4474 13625 8294 7845 7405 6972 6545 6125 5709 5297 4887 4479 13375 834 7886 7441 7004 6573 6148 5728 5311 4897 4484 13125 8388 793 748 7038 6603 6173 5748 5326 4907 449 12875 844 7977 7522 7075 6634 62 5769 5343 4918 4496 12625 8495 8026 7566 7114 6668 6228 5792 536 493 4502 12375 8553 8079 7613 7155 6703 6258 5816 5378 4943 4509 12125 8615 8135 7663 7199 6741 6289 5842 5398 4956 4517 11875 868 8194 7716 7245 6781 6323 5869 5418 4971 4524 11625 8749 8256 7771 7294 6823 6358 5898 544 4986 4532 11375 8822 8322 783 7346 6868 6396 5928 5463 5002 4541 11125 8899 8392 7892 7401 6915 6435 596 5488 5018 455 10875 898 8465 7958 7458 6965 6477 5994 5514 5036 456 10625 9066 8542 8027 7519 7018 6521 6029 5541 5055 457 10375 9155 8624 81 7583 7073 6568 6067 557 5075 4581 10125 925 8709 8177 7651 7131 6617 6107 56 5095 4592 9875 9349 8799 8257 7722 7193 6669 6149 5632 5117 4604 9625 9454 8894 8342 7797 7257 6723 6193 5665 514 4617 9375 9564 8994 8431 7875 7325 678 6239 5701 5165 463 9125 9679 9098 8525 7958 7397 684 6288 5738 519 4644 8875 98 9208 8624 8045 7472 6904 6339 5777 5217 4659 8625 9927 9324 8727 8137 7551 6971 6393 5819 5246 4674 8375 1006 9445 8836 8233 7635 7041 645 5862 5276 4691 8125 102 9572 895 8334 7722 7115 651 5908 5307 4708 7875 1035 9706 907 844 7814 7192 6573 5956 5341 4726 7625 105 9846 9197 8552 7911 7274 664 6007 5376 4745 7375 1066 9994 933 867 8014 7361 671 6061 5413 4766 7125 1083 1015 947 8794 8121 7452 6784 6118 5452 4787 6875 1101 1031 9617 8925 8235 7548 6862 6178 5494 481 6625 112 1049 9773 9063 8356 765 6945 6241 5537 4834 6375 114 1067 9937 9209 8483 7757 7033 6308 5584 4859 6125 1161 1086 1011 9364 8618 7872 7126 638 5634 4887 5875 1183 1106 103 9528 8761 7993 7225 6456 5686 4916 5625 1207 1128 1049 9703 8914 8123 7331 6537 5743 4947 5375 1231 1151 107 9889 9076 8261 7443 6624 5803 498 5125 1258 1175 1092 1009 925 8409 7564 6717 5867 5015 4875 1286 1201 1116 103 9436 8567 7694 6816 5936 5053 4625 1316 1229 1142 1053 9637 8738 7833 6924 601 5094 4375 1349 1259 1169 1078 9853 8922 7983 7039 609 5138 4125 1384 1292 1199 1104 1009 912 8146 7164 6177 5186 3875 1422 1327 1231 1133 1034 9336 8321 7299 627 5237 3625 1463 1365 1266 1165 1062 957 8512 7445 637 5291 3375 1508 1407 1304 1199 1092 9824 8719 7603 6479 middot535 3125 1557 1453 1346 1237 1124 101 8943 7773 6595 5412 2875 1612 1504 1393 1278 116 104 9185 7956 6719 5478 2625 1673 1561 1444 1323 1199 1073 9446 8152 6851 5546 2375 1741 1624 1501 1373 1242 1108 9725 8359 6989 5617 2125 1818 1695 1565 1429 1289 1146 1002 8575 713 5687 1875 1906 1775 1636 149 1339 1186 1032 8792 727 5755 1625 2007 1868 1716 1556 1392 1227 1062 9001 7401 5818
119
1375 1125 875 625 375 125
2127 2271 2449 2679 2994 3436
1975 2103 226
2467 2776 3361
1807 1912 2032 2173 2333 2469
1629 1707 1788 1863 191
1868
1447 1501 1548 1575 1559 1454
1266 1301 1324 1324 1279 1163
109 1111 112
1107 1058 9548
9183 9311 934
9205 8813 8043
7514 7591 7611 7544 735
6956
5873 5918 5953 5988 6049 6199
F6 Freezer Wall Simulation Output Including Anti-sweat Condenser Tube
INPUT PARAMETERS
Section Dimensions (mm) Width Length Depth Steel skin thickness Plastic skin thickness
5600 2000 1580 6500 2500
Mesh Geometry dx dy Number nodes in x-direction Number nodes in y-direction Number of steel skin nodes (including corner 00) Steel nodes under the seal Tube located at node
2800 2500 20 80
11 2 to 10 6
Steel skin conductivity (Wm K)
Foam insulation conductivity (Wm K) Plastic skin conductivity (Wm K)
Outside h (Wm2 K) Inside h (Wm2 K) Outside Temp (C) Inside Temp (C)
5400 27000E-02 1500 6870 6410 2100 -1000
OUPUT PARAMETERS
Number of iterations 879
ID Heat Flux Thru Wall (Wm2) 1362
Heat Transfer Along Metal Skin Under Seal node to node qm[Wm2] Qm[W]
2 3 -15024E+04 -1543 3 4 -15111E+04 -1552 4 5 -15205E+04 -1562 5 6 -15310E+04 -1572 6 7 5828 5986 7 8 5690 5844 8 9 5535 5684 9 10 5348 5492
Maximum difference (Is) 1356
j qleft[W] qright[W] -1 -1566 5928
120
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63
0 -62085E-02 -31363E-02 -5 9522E-02 -40097E-02 -44286E-02 -30955E-02 -33621E-02 -21814E-02 -25242E-02 -1 4577E-02 -1 8767E-02 -9 6252E-03 -13815E-02 -58162E-03 -10387E-02 -31499E-03 -73398E-03 -1 6265E-03 -54353E-03 -10285E-04
-35309E-03 27805E-04 -23882E-03 65891E-04 -16265E-03 14208E-03 -1 24 55E-03 14207E-03 -48371E-04 14207E-03 -10285E-04 10398E-03 -10285E-04 10399E-03 -10281E-04 10398E-03 -48371E-04 65891E-04 -1 02 85E-04 27805E-04 -86465E-04 16377E-04 -48375E-04 -52182E-04 -86465E-04 -97886E-04 -1 2455E-03 -13979E-03 -1 7788E-03 -16645E-03 -19692E-03 -21597E-03 -24263E-03 -25786E-03 -30357E-03 -30357E-03 -33404E-03 -35309E-03 -3 7975E-03 -3 9879E-03 -41784E-03 -44450E-03 -45974E-03 -49402E-03 -50164E-03 -53592E-03 -54353E-03 -58162E-03 -58543E-03 -62733E-03 -62733E-03 -66923E-03 -66542E-03 -71493E-03 -70351E-03 -75303E-03 -74541E-03 -7 9111E-03 -77969E-03 -83301E-03 -81397E-03 -87491E-03 -85206E-03 -90919E-03 -88634E-03 -94728E-03 -92062E-03 -97775E-03 -95109E-03 -10158E-02 -98537E-03 -10463E-02 -1 0158E-02 -10768E-02 -1 04 63E-02 -11073E-02 -10692E-02 -11377E-02 -10996E-02 -11644E-02 -11225E-02 -1 1949E-02 -11492E-02 -12215E-02 -11758E-02 -12444E-02 -11949E-02 -12672E-02 -12177E-02 -12901E-02 -12368E-02 -13129E-02 -12596E-02 -1 3282E-02 -12748E-02 -1 351 OE-02 -1 2977E-02 -13701E-02 -13129E-02 -1 3853E-02 -13282E-02 -14005E-02 -1 3434E-02 -14158E-02 -13586E-02 -14310E-02 -1 3701E-02 -14463E-02
121
64 -1 3815E-02 -1 4577E-02 65 -1 392 9E-02 -14691E-02 66 -14005E-02 -14767E-02 67 -14120E-02 -14881E-02 68 -14196E-02 -14958E-02 69 -1 4272E-02 -15034E-02 70 -14310E-02 -15110E-02 71 -1 4386E-02 -1 5148E-02 72 -14424E-02 -15186E-02 73 -14463E-02 -15224E-02 74 -14501E-02 -1 5262E-02 75 -14501E-02 -1 5300E-02 76 -14539E-02 -15262E-02 77 -14539E-02 -15300E-02 78 -1 4539E-02 -15262E-02 79 -14501E-02 -1 5300E-02
Qleft [Wj -1653 Qright [Wj 5163 Percent entering cabinet 2380
Freezer Nodal Temperatures (Condenser Tube)
x(mm) y(mm) 14 42 70 98 126 154 182 210 238 266
19875 9606 8457 7334 6235 516 4107 3075 2064 107 00944 19625 9596 8448 7325 6227 5152 4099 3068 2056 1064 00882 19375 9591 8443 732 6222 5148 4095 3064 2053 106 00850 19125 9591 8443 732 6222 5147 4095 3064 2052 106 00847 18875 9596 8448 7325 6226 5151 4099 3067 2056 1063 00873 18625 9606 8457 7334 6235 5159 4106 3074 2062 1069 00928 18375 9621 8472 7347 6248 5171 4118 3085 2072 1078 01013 18125 9641 8491 7366 6265 5188 4133 3099 2085 109 01128 17875 9666 8514 7388 6287 5208 4152 3117 2102 1106 01272 17625 9696 8543 7416 6313 5233 4176 3139 2123 1125 01447 17375 9731 8577 7448 6343 5262 4203 3165 2147 1147 01652 17125 9772 8616 7485 6378 5295 4234 3194 2174 1173 01888 16875 9817 8659 7526 6418 5333 427 3228 2206 1202 02156 16625 9868 8708 7573 6462 5375 431 3265 224 1234 02455 16375 9924 8762 7624 6511 5421 4353 3306 2279 127 02786 16125 9985 8821 7681 6565 5472 4402 3352 2322 131 03149 15875 1005 8885 7742 6624 5528 4454 3401 2368 1353 03546 15625 1012 8954 7809 6687 5588 4511 3455 2418 1399 03976 15375 102 9029 7881 6755 5653 4573 3513 2472 145 04441 15125 1029 911 7958 6829 5723 4639 3575 253 1504 0494 14875 1038 9196 804 6907 5798 4709 3641 2592 1562 05474 14625 1047 9287 8128 6991 5877 4784 3712 2659 1623 06045 14375 1057 9385 8221 708 5962 4865 3787 2729 1689 06652 14125 1068 9488 832 7175 6052 495 3868 2804 1759 07297 13875 1079 9597 8424 7275 6147 504 3952 2884 1833 07981 13625 1091 9713 8535 738 6247 5135 4042 2968 1911 08704 13375 1104 9834 8651 7491 6353 5235 4136 3056 1993 09466 13125 1117 9962 8774 7608 6464 534 4236 315 208 1027 12875 1131 101 8902 7731 6581 5451 434 3248 2172 1112 12625 1146 1024 9037 786 6704 5568 445 3351 2268 1201 12375 1161 1038 9178 7995 6833 569 4566 3459 2369 1294
122
12125 1177 1054 9326 8136 6967 5818 4686 3572 2475 1392 11875 1194 107 9481 8284 7108 5951 4813 3691 2585 1494 11625 1211 1087 9642 8439 7256 6091 4945 3815 2701 1602 11375 1229 1104 981 86 7409 6237 5083 3945 2822 1714 11125 1248 1122 9985 8768 757 639 5227 4081 2949 1832 10875 1268 1141 1017 8943 7737 6549 5378 4222 3082 1954 10625 1288 1161 1036 9125 7911 6714 5534 437 322 2083 10375 1309 1181 1055 9314 8092 6887 5698 4524 3364 2217 10125 1331 1203 1076 9511 8281 7067 5868 4685 3514 2356 9875 1354 1225 1097 9716 8477 7254 6046 4852 3671 2502 9625 1378 1248 1119 9929 8681 7448 6231 5026 3835 2654 9375 1402 1271 1142 1015 8893 7651 6423 5208 4005 2813 9125 1428 1296 1166 1038 9113 7861 6623 5398 4183 2979 8875 1454 1321 1191 1062 9342 808 6832 5595 4369 3152 8625 1481 1348 1216 1086 9579 8308 7049 5801 4562 3333 8375 1509 1375 1243 1112 9826 8545 7275 6015 4764 3522 8125 1538 1403 127 1139 1008 8791 751 6238 4975 3719 7875 1568 1432 1299 1166 1035 9047 7755 6472 5196 3925 7625 1598 1462 1328 1195 1063 9314 8011 6715 5426 4142 7375 163 1494 1358 1224 1091 9591 8278 697 5667 4368 7125 1663 1526 139 1255 1121 9881 8556 7236 5919 4606 6875 1697 1559 1422 1287 1152 1018 8847 7514 6184 4855 6625 1731 1593 1456 132 1185 105 9151 7806 6462 5118 6375 1767 1629 1491 1355 1218 1083 9469 8113 6755 5394 6125 1804 1665 1527 139 1254 1117 9804 8435 7063 5686 5875 1842 1703 1565 1428 129 1153 1015 8774 7388 5995 5625 1881 1742 1604 1466 1329 1191 1052 9133 7732 6322 5375 1921 1782 1644 1507 1369 1231 1091 9511 8097 6669 5125 1962 1824 1686 1549 1411 1272 1133 9913 8485 7039 4875 2004 1867 173 1593 1455 1317 1176 1034 8899 7435 4625 2047 1912 1776 164 1502 1363 1223 108 9341 7859 4375 2092 1958 1823 1688 1552 1413 1272 1128 9816 8315 4125 2138 2005 1873 1739 1604 1466 1325 1181 1033 8807 3875 2184 2055 1925 1793 166 1523 1382 1238 1088 934 3625 2232 2106 1979 1851 1719 1584 1444 1299 1148 992 3375 2282 216 2037 1911 1783 1649 1511 1366 1214 1055 3125 2332 2215 2097 1976 1851 1721 1584 1439 1286 1125 2875 2384 2273 2161 2045 1925 1798 1663 152 1366 1202 2625 2436 2334 2229 212 2005 1883 1751 1609 1455 1288 2375 249 2397 2301 22 2093 1976 1849 1708 1554 1384 2125 2546 2463 2377 2287 2188 2079 1957 182 1666 1493 1875 2602 2532 2459 238 2293 2193 2079 1946 1793 16 17 1625 266 2605 2546 2482 2407 232 2215 2089 1939 176 1375 2719 2681 264 2592 2533 2461 2369 2253 2108 1928 1125 2779 2761 2739 271 2671 2618 2543 244 2305 2128 875 2841 2844 2844 2838 2822 2792 2739 2655 2535 2367 625 2903 293 2954 2974 2986 2984 2959 2899 2802 2658 375 2967 3018 3069 3117 316 3194 3209 3173 3108 3009 125 3032 3108 3186 3263 3342 3421 35 347 344 3412
x (nun) y (nun) 294 322 350 378 406 434 462 490 518 546
19875 -0865 -1811 -2743 -3663 -4573 -5474 -6368 -7257 -8141 -9022 19625 -0871 -1816 -2747 -3667 -4577 -5477 -6371 -7259 -8142 -9024 19375 -0874 -1819 -275 -3669 -4578 -5479 -6372 -726 -8143 -9024 19125 -0874 -1819 -275 -367 -4579 -5479 -6372 -726 -8144 -9025 18875 -0872 -1817 -2748 -3668 -4577 -5478 -6372 -7259 -8143 -9025
123
18625 -0867 -1812 -2744 -3664 -4574 -5476 -637 -7258 -8142 -9024 18375 -0859 -1805 -2738 -3659 -457 -5472 -6366 -7256 -8141 -9023 18125 -0848 -1796 -273 -3652 -4563 -5466 -6362 -7252 -8139 -9022 17875 -0835 -1784 -2719 -3642 -4555 -546 -6357 -7248 -8136 -9021 17625 -0819 -1769 -2706 -3631 -4546 -5451 -635 -7243 -8132 -9019 17375 -0800 -1752 -2691 -3618 -4534 -5442 -6342 -7237 -8128 -9017 17125 -0779 -1733 -2673 -3602 -4521 -5431 -6334 -7231 -8124 -9014 16875 -0754 -1711 -2654 -3585 -4506 -5418 -6323 -7223 -8119 -9012 16625 -0727 -1686 -2632 -3565 -4489 -5404 -6312 -7214 -8113 -9009 16375 -0697 -1659 -2607 -3544 -447 -5389 -6299 -7205 -8106 -9005 16125 -0664 -1629 -258 -352 -445 -5371 -6286 -7194 -8099 -9001 15875 -0627 -1596 -2551 -3494 -4428 -5353 -6271 -7183 -8091 -8997 15625 -0588 -156 -2519 -3466 -4404 -5332 -6254 -717 -8083 -8993 15375 -0545 -1522 -2484 -3436 -4377 -531 -6236 -7157 -8074 -8988 15125 -0500 -148 -2447 -3403 -4349 -5287 -6217 -7143 -8064 -8983 14875 -0451 -1436 -2408 -3368 -4319 -5261 -6197 -7127 -8053 -8977 14625 -0399 -1388 -2365 -3331 -4287 -5234 -6175 -7111 -8042 -8971 14375 -0343 -1338 -232 -3291 -4253 -5206 -6152 -7093 -803 -8965 14125 -0284 -1284 -2272 -3249 -4216 -5175 -6127 -7074 -8017 -8958 13875 -0221 -1228 -2221 -3204 -4177 -5143 -6101 -7054 -8004 -8951 13625 -0155 -1168 -2168 -3157 -4137 -5108 -6073 -7033 -7989 -8943 13375 -0085 -1104 -2111 -3107 -4093 -5072 -6044 -7011 -7974 -8935 13125 -0011 -1037 -2051 -3054 -4048 -5034 -6013 -6987 -7958 -8927 12875 0065 -0966 -1988 -2998 -4 -4993 -598 -6963 -7941 -8918 12625 01474 -0892 -1922 -294 -3949 -4951 -5946 -6937 -7924 -8909 12375 0233 -0815 -1852 -2878 -3896 -4906 -591 -6909 -7905 -8899 12125 03229 -0733 -1779 -2814 -384 -4859 -5872 -688 -7885 -8888 11875 0417 -0648 -1702 -2746 -3782 -481 -5832 -685 -7865 -8877 11625 05157 -0558 -1622 -2675 -372 -4758 -5791 -6819 -7843 -8866 11375 06189 -0464 -1537 -2601 -3656 -4704 -5747 -6785 -7821 -8854 11125 07269 -0366 -1449 -2523 -3589 -4648 -5701 -675 -7797 -8841 10875 08398 -0263 -1357 -2441 -3518 -4588 -5653 -6714 -7772 -8828 10625 09577 -0156 -126 -2356 -3444 -4526 -5603 -6676 -7746 -8814 10375 1081 -0044 -116 -2267 -3367 -4461 -555 -6636 -7718 -88 10125 121 00732 -1054 -2174 -3286 -4393 -5495 -6594 -769 -8785 9875 1344 01957 -0943 -2076 -3202 -4322 -5437 -655 -766 -8769 9625 1484 03238 -0828 -1974 -3113 -4247 -5377 -6504 -7628 -8752 9375 1631 04575 -0708 -1867 -302 -4169 -5314 -6456 -7596 -8734 9125 1784 05974 -0582 -1755 -2923 -4087 -5247 -6405 -7561 -8716 8875 1944 07436 -0450 -1638 -2822 -4001 -5178 -6352 -7525 -8697 8625 2111 08966 -0312 -1516 -2715 -3911 -5105 -6296 -7487 -8676 8375 2286 1057 -0167 -1387 -2604 -3817 -5028 -6238 -7447 -8655 8125 2469 1224 -0015 -1253 -2486 -3718 -4948 -6177 -7405 -8633 7875 2661 14 0143 -1111 -2363 -3614 -4863 -6112 -736 -8609 7625 2861 1584 031 -0962 -2234 -3504 -4774 -6044 -7314 -8584 7375 3072 1778 04856 -0806 -2097 -3389 -468 -5972 -7265 -8558 7125 3293 1982 06704 -0641 -1954 -3267 -4581 -5896 -7213 -853 6875 3526 2196 08652 -0467 -1802 -3138 -4476 -5816 -7158 -8501 6625 3771 2422 1071 -0283 -1641 -3002 -4366 -5732 -71 -847 6375 403 2661 1288 -0089 -1471 -2858 -4248 -5642 -7038 -8437 6125 4303 2914 1519 01168 -1291 -2705 -4124 -5547 -6973 -8402 5875 4593 3182 1763 03357 -11 -2542 -3991 -5445 -6904 -8365 5625 49 3467 2023 05686 -0896 -2369 -385 -5338 -683 -8326 5375 5227 3771 23 08169 -0678 -2185 -37 -5223 -6751 -8284 5125 5576 4095 2596 1082 -0446 -1988 -354 -5101 -6668 -8239 4875 5949 4442 2913 1366 -0198 -1778 -337 -4971 -6579 -8193 4625 635 4814 3254 167 00669 -1553 -3187 -4832 -6485 -8143 4375 6781 5215 3619 1997 03519 -1313 -2993 -4685 -6385 -809
124
4125 7246 5647 4014 2349 06577 -1055 -2785 -4528 -6279 -8036 3875 775 6116 444 2728 0986 -0780 -2565 -4362 -6168 -7978 3625 8299 6625 4902 3137 1339 -0486 -233 -4187 -6051 -7919 3375 8899 718 5404 3579 1717 -0173 -2082 -4003 -593 -7859 3125 9558 7787 595 4057 2122 01586 -1823 -3813 -5806 -7798 2875 1028 8455 6545 4573 2555 0508 -1553 -3618 -568 -7739 2625 1109 9192 7197 513 3014 0872 -1277 -3422 -5558 -7683 2375 12 1001 7912 5729 3497 1245 -1002 -3233 -5442 -7633 2125 1301 1093 8698 6373 3998 1618 -0739 -3059 -534 -7592 1875 1418 1196 9566 7058 4508 1975 -0503 -2914 -5262 -7564 1625 1552 1314 1053 778 5007 2292 -0319 -2818 -5218 -7554 1375 171 1452 116 8525 5462 2528 -0224 -2798 -5226 -7564 1125 19 1616 1281 9263 5815 2621 -0272 -2892 -5304 -7597 875 2136 182 1417 9928 5968 2477 -0537 -3151 -5478 -7651 625 244 2095 1569 1037 575 1953 -112 -3637 -5773 -7713 375 2845 2514 1726 1027 4873 0854 -2146 -4427 -6224 -7757 125 3384 3296 1814 8879 2904 -1057 -3745 -5602 -6885 -7725
F bull 7 Seal Simulation Source Code and Ouput
Program Seal
c This program simulates the heat transfer characteristics of an c idealized refrigerator door gasket The steady-state temperature c profile is determined numerically from a 2-D finite difference c code
cxxxxxxxxxxxxx Parameters and Variablesxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
integer NNNWnsurfijjlloopiters real emmissigmakhihoTiTodelsNN real depthareatolkair
parameter (N=6) parameter (NN=20) parameter (W=7) parameter (nsurf=4N-l) parameter (emmis=09) parameter (sigma=567e-8) parameter (k=03) parameter (kair=0026) parameter (hi=641) parameter (ho=687) parameter (Ti=1032) parameter (To=209) parameter (sNN=02) parameter (del=sNNNN) parameter (depth=10) parameter (area=deldepth) parameter (tol=10)
real x(Onsurf)y(Onsurf)len(ONOnsurf) real F(OnsurfOnsurf) real T(-lNN+lONN)radl(nsurf+l)rad(Onsurf) real Eb(Onsurf)bvector(nsurf+l)Amatrix(nsurf+lnsurf+l) real difasumqsumqtotqin(NN-l) real rlr2r3r4r5
125
real clc2c3c4c5c6c7
open (lfilemiddotGasketoutposition-rewind) open (2file=Gasket(q)outpositionmiddotrewind)
cxxxxxxxxxxxxx Determine Viewfactors xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
call Points(Ndelnsurfxy) call length(Ndelnsurfxylen) call Vfactor(NdelnsurflenF)
cxxxxxxxxxxxxx Resistors (C-m2W)
c Interior x- and y-directions rl=delk
c Exterior to outdoor ambient r2=1ho
c Exterior to indoor ambient r3-1hi
c Radiation r4=(1-emmis)emmis
c Air r5=delkair
xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
cxxxxxxxxxxxxx Guass-Siedel Iteration xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
c Begin massive loop to determine the steady-state temperature c distribution across the section First update the interior nodes c by considering the radiative heat transfer among the interior c surfaces The radiative transfer is updated by calling a routine c which computes the new radiosities every iteration Loop until c tolerance is met
c Initialize temperature field do 10 i=ONN
do 11 jONN T(ij)=50
11 continue 10 continue
do 15 j=ONN T(-1j)=250 T(NN+lj)=50
15 continue
c Set temperatures for row y=O and row y=NN do 20 i=ONN
T(iO)=fl(idel) T(iNN)=f2(idel)
20 continue
cxxxxxxxxxxxxx Begin Iteration xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
loop=l iters=l do while (loop eq 1)
c Update radiosities using new temps and update interior surface nodes
call Jsolver(FemmissigmaTNNNWnsurfradlradEb + bvectorAmatrix)
c interior corners cl=area (2rl) c2=arearl
126
c3=area (2rl) c4=arearl c5=arear4 c6=1(cl+c2+c3+c4)
T(WW)=c6(clT(W+lW)+c2T(W-lW)+c3T(WW+l)+ + c4T(WW-l)+c5(rad(0)-Eb(0raquo)
cl=arearl c2=area(2rl) c3=area(2rl) c4=arearl c5=arear4 c6-1(cl+c2+c3+c4) T(W+NW)=c6(clT(W+N+lW)+c2T(W+N-lW)+c3T(W+NW+l)+
+ c4T(W+NW-l)+c5(rad(N)-Eb(Nraquo) clarearl c2-area (2rl) c3-arearl c4=area(2rl) c5=arear4 c6=1(cl+c2+c3+c4) T(W+NW+N)=c6 (clT(W+N+lW+N)+c2T(W+N-lW+N) +c3T(W+NW+N+l)+
+ c4T(W+NW+N-l)+c5(rad(2N)-Eb(2Nraquo) cl=area(2rl) c2=arearl c3=arearl c4=area(2rl) c5=arear4 c6=1(cl+c2+c3+c4) T(WW+N)=c6 (clT(W+lW+N) +c2T(W-lW+N)+c3T(WW+N+l) +
+ c4T(WW+N-l)+c5(rad(3N)-Eb(3Nraquo)
c Interior surface y=W jl=l do 22 i=W+lW+N-l
cl=area(2rl) c2=area (2rl) c4=arearl c5=arear4 c7=arear5 c6=1(cl+c2+c4+c7) T(iW)=c6(clT(i+lW)+c2T(i-lW)+
+ c7T(iW+l)+c4T(iW-l)+c5(rad(jl)-Eb(jlraquo) jl=j1+1
22 continue
c Interior surface y=N+W jl=3N-l do 25 i=W+lW+N-l
cl=area(2rl) c2=area (2rl) c3=arearl c5=arear4 c7=arear5 c6=1(cl+c2+c3+c7) T(iW+N)=c6(clT(i+lW+N)+c2T(i-lW+N)+
+ c7T(iW+N-l)+c3T(iW+N+l)+c5(rad(jl)-Eb(jlraquo) jl=jl-l
25 continue
c interior surface x=W jl=4N-l do 30 j=W+lW+N-l
c2=arearl
127
c3=area (2rl) c4=area(2rl) c5-arear4 c7-arear5 c6-1(c2+c3+c4+c7) T(Wj)-c6(c7T(W+lj)+c2T(W-lj)+c3T(Wj+l)+
+ c4T(Wj-l)+c5(rad(jl)-Eb(jl))) jl=jl-l
30 continue
c interior surface x=W+N jl=N+l do 35 j-W+lW+N-l
cl=arearl c3=area(2rl) c4=area (2rl) c5-arear4 c7-arear5 c6-1(cl+c3+c4+c7) T(W+Nj)=c6(clT(W+N+lj)+c7T(W+N-lj)+c3T(W+Nj+l)+
+ c4T(W+Nj-l)+c5(rad(jl)-Eb(jl))) jl=j1+1
35 continue
c Interior air nodes do 37 j=W+lN+W-l
do 38 i=W+lN+W-l call sseqn(Tr5r5r5r5areaareaareaareaijNN)
38 continue 37 continue
c Solid nodes do 40 i=lNN-l
do 45 jlW-l call sseqn(TrlrlrlrlareaareaareaareaijNN)
45 continue do 50 j=W+N+lNN-l
call sseqn(TrlrlrlrlareaareaareaareaijNN) 50 continue 40 continue
do 55 j=WW+N do 60 i=lW-l
call sseqn(TrlrlrlrlareaareaareaareaijNN) 60 continue
do 65 i=W+N+lNN-l call sseqn(TrlrlrlrlareaareaareaareaijNN)
65 continue 55 continue
c Side boundaries do 70 j=lNN-l
call sseqn(Trlr2rlrlareaareaarea2area20jNN) call sseqn(Tr3rlrlrlareaareaarea2area2NNjNN)
70 continue
c Apply energy balance around the boundary of the gasket to determine c stopping criterium dif
dif-OO dif=dif+(area(2rl))(T(00)-T(01)) dif=dif+(area(2rl))(T(0NN)-T(0NN-l)) do 90 i=lNN-l
dif=dif+(arearl)(T(iO)-T(il)) dif=dif+(arearl)(T(iNN)-T(iNN-l))
128
90 continue dif=dif+(area(2r1raquo(T(NN0)-T(NN1raquo dif=dif+(area(2r1raquo(T(NNNN)-T(NNNN-1raquo
do 95 j=1NN-1 dif=dif+(arear2)(To-T(0jraquo dif-dif+(arear3)(Ti-T(NNjraquo
95 continue
print dif
c Stopping criterium if (dif It toll then
loop-O endif if (iters eq 10000) then
loop=O endif
iters=iters+1 end do
cxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx c Compute heat flux into the cabinet
qsum=OO asum=OO do 97 j=1NN-1
qin(j)=hiarea(T(NNj)-Ti) qsum=qsum+qin(j) asum=asum+area
97 continue qtot=qsumasum write(2) heat flux to interior [Wm2)qtot
do 100 j=NNO-l write(l) (T(ij)i=ONN)
100 continue
pause stop end
c----------------------------------------------------------------------shyc------~----------------------------------------------------------------
Subroutine Points(Ndelnsurfxy)
integer Nnsurfi real delincrx(Onsurf)y(Onsurf)
x(O)=OO y(0)=del2
c Points along y=O edge incr-OO do 10 i=lN
y(i)=OO x(i)=(del2)+incr incr=incr+del
10 continue
c Points along x=Ndel edge incr=OO do 20 i=N+12N
x(i)=Ndel
129
y(i)-(del2)+incr incr-incr+del
20 continue
c Points along y=Ndel edge incr=OO do 30 i=3N2N+l-1
y(i)-Ndel x(i)=(del2)+incr incr-incr+del
30 continue
c Points along x-O edge incr=OO do 40 i-nsurf3n+l-1
xli) -00 y(i)-laquo3del)2)+incr incr-incr+del
40 continue
return end
c----------------------------------------------------------------------shyc-----------------------------------------------------------------------
Subroutine length(Ndelnsurfxylen)
integer Nnsurfij real dellen(ONOnsurf)x(Onsurf)y(Onsurf)
c Special case surface 0 do 10 j=Onsurf
len(0j)=sqrtlaquox(0)-x(jraquo2+(y(0)-y(jraquo2) 10 continue
c Surfaces along y=O do 20 i=IN-l
do 30 j=Onsurf len(ij)=sqrtlaquox(i)-x(jraquo2+(y(i)-y(jraquo2)
30 continue 20 continue
c Special case surface N do 50 j=Onsurf
len(Nj)=sqrtlaquox(N)-x(jraquo2+(y(N)-y(jraquo2) 50 continue
return end
c----------------------------------------------------------------------shyc-----------------------------------------------------------------------
Subroutine Vfactor(NdelnsurflenF)
integer Nnsurfijjlj2 real dellen(ONOnsurf)F(OnsurfOnsurf)Lzero
c Determine viewfactors for special case of surface 0 Lzero=delsqrt(20) do 10 j=Onsurf
if (j eq 0) then F(Oj)=OO
elseif (j eq nsurf) then F(Oj)=(len(Oj)+len(10)-len(00)-len(ljraquo(2Lzero)
else F(0j)=(len(0j)+len(lj+l)-len(Oj+l)-len(ljraquo(2Lzero)
130
endif 10 continue
c Determine viewfactors for surfaces on edge y-O
do 20 i=IN-l do 30 j=Onsurf
if (i eq j) then F(ij)=OO
elseif (j eq nsurf) then F(ij)=(len(ij)+len(i+l0)-len(i0)-len(i+ljraquo(2de1)
else F(ij)=(len(ij)+len(i+lj+l)-len(ij+l)-len(i+ljraquo(2del)
endif sum=sum+F(ij)
30 continue 20 continue
c Determine viewfactors for all other surfaces do 40 iON-l
do 50 j=03N-l F(i+Nj+N)=F(ij)
50 continue do 60 j=3Nnsurf
F(i+Nj-3N)=F(ij) 60 continue
do 70 j=02N-1 F(i+2Nj+2N)=F(ij)
70 continue do 80 j=2Nnsurf
F(i+2Nj-2N)=F(ij) 80 continue
do 90 j=ON-l F(i+3Nj+3N)=F(ij)
90 continue do 100 j=Nnsurf
F(i+3Nj-N)=F(ij) 100 continue
40 continue
return end
c----------------------------------------------------------------------shyc-----------------------------------------------------------------------
Subroutine Jsolver(FemmissigmaTNNNWnsurfradlradEb + bvectorAmatrix)
integer NNNnsurfij real emmissigmaF(OnsurfOnsurf) real T(-INN+10NN)rad1(nsurf+l)rad(0nsurf) real Eb(0nsurf)bvector(nsurf+1)Amatrix(nsurf+lnsurf+l)surn
c Compute Eb for all surfaces do 10 i-ON-l
Eb(i)=sigma(T(i+WW) 4) Eb(i+N)=sigma(T(W+Ni+W)4)
10 continue incr=W+N do 20 i=0N-1
Eb(i+2N)=siqrna(T(incrW+N) 4) Eb(i+3N)=sigma(T(Wincr)4) incr=incr-1
20 continue
131
c Assign values to vector b do 30 i=Onsurf
bvector(i+l)-(emmis(l-emmisraquoEb(i) 30 continue
c Assign values to matrix A do 40 i-Onsurf
do SO j=Onsurf Amatrix(i+lj+l)--F(ij)
SO continue 40 continue
c Override diagonal terms do 60 i-Onsurf
sum-OO do 70 j-Onsurf
sum-sum+F(ij) 70 continue
Amatrix(i+li+l)-(emmis(l-emmisraquo+sum 60 continue
c Call routine to solve the set of equations for unknown JS call gaussy(Amatrixbvectorradlnsurf+l)
do 80 i=Onsurf rad(i)=radl(i+l)
80 continue
return end
c----------------------------------------------------------------------shyc-----------------------------------------------------------------------
Subroutine Gaussy(abxn) c
integer nkiimaxjkplusllplus real a(nn)b(n)x(n)amaxbtempatemp
+ aeon sum
do 28 k=l n amax=OO do 4 i=kn if(abs(a(ikraquo-abs(amaxraquo442
2 amax=a(ik) imax=i
4 continue if(abs(amax)-0le-15)101014
10 printO equations are not independent return
14 btemp=b(k) b(k)=b(imax) b(imax)=btemp do 18 j=kn
atemp=a(k j) a(kj)=a(imaxj)
18 a(imaxj)=atemp kplus=k+l if(k-n)222828
22 do 24 i=kplusn b(i)=b(i)-b(k)a(ik)a(kk) acon=a(ik) do 24 j=kn
24 a(ij)=a(ij)-a(kj)acona(kk) 28 continue
132
l=n 32 sum=OO
if(1-n)343838 34 lplus-1+1
do 36 j-lplusn 36 sum=sum+a(lj)x(j) 38 continue
x(l)-(b(l)-sum)a(ll) if(1-1)424240
40 1-1-1 goto 32
42 return end
c----------------------------------------------------------------------shyc-----------------------------------------------------------------------
Subroutine sseqn(TriplusriminusrjplusrjminusAiplus + AiminusAjplusAjminusijNN)
c This subroutine computes the temperature at node (ij) c given the temperatures of the surrounding nodes and c the resistances leading to these nodes
integer ijNN real T(-1NN+10NN)riplusriminusrjplusrjminus real AiplusAiminusAjplusAjminus real c1c2c3c4c5
c1=Aiplusriplus c2=Aiminusriminus c3=Ajplusrjplus c4=Ajminusrjminus c5=1(c1+c2+c3+c4)
T(ij)=c5(c1T(i+1j)+c2T(i-1j)+c3T(ij+1)+c4T(ij-1raquo
return end
c----------------------------------------------------------------------shyc----------------------------------------------------------------------shy
real function f1(x) c door BC
real x f1-18520 - 23413x
return end
c----------------------------------------------------------------------shyc----------------------------------------------------------------------shy
real function f2(x) c wall BC
real x f2=18128 - 3475x
return end
c----------------------------------------------------------------------shyc----------------------------------------------------------------------shy
133
Fresh Food Compartment Simulations Results
Run 1 The prescribed temperature profiles are
Wall 19203 - 1908 x Door 19203 - 1206 x
(x is in meters)
Outdoor Ambient = 210 degC Local Indoor Ambient = 1533 degC
Run 2 The prescribed temperature profiles are
Wall 18989 - 2024 x Door 19078 - 1326 x
(x is in meters)
Outdoor Ambient = 210 degC Local Indoor Ambient = 1496 degC
Run 3 The prescribed temperature profiles are
Wall 1895 - 1998 x Door 19053 - 1384 x
(x is in meters)
Outdoor Ambient = 208 degC Local Indoor Ambient = 1491 degC
Ayem~ Values Wall 1905 - 1977 x Door 1913 - 1384 x
(x is in meters)
Ave Outdoor Ambient = 209 degC Ave Local Indoor Ambient =1507 degC
Loss from Fresh Food == 10 W
134
Freezer Compartment Simulations Results
Run 1 The prescribed temperature profiles are
Wall 1821 - 343 x Door 18606 - 2354 x
(x is in meters)
Outdoor Ambient = 210 degC Local Indoor Ambient = 1029 degC
Run 2 The prescribed temperature profiles are
Wall 18182 - 3542 x Door 18544 - 2398 x
(x is in meters)
Outdoor Ambient = 210 degC Local Indoor Ambient = 1042 degC
Run 3 The prescribed temperature profiles are
Wall 17993 - 3452 x Door 18411 - 2272 x
(x is in meters)
Outdoor Ambient = 208 degC Local Indoor Ambient = 1024 degC
Ayera~e Values Wall 18128 - 3475 x Door 18520 - 23413 x
(x is in meters)
Ave Outdoor Ambient = 209 degC Ave Local Indoor Ambient = 1032 degC
Loss from Fresh Food = 157 W
135
1 INTRODUCTION
New regulations recently announced by the Department ofEnergy call for substantial
energy efficiency increases for household appliances by 1993 The refrigerator is of
particular interest since it is the largest household consumer of electricity and accounts for a
large part of the 8 of the electricity used in the US for food-cooling both residential and
commercial In addition to efficiency standards regulations are being imposed on the use
of CFCs completely banning their use by the year 2000 (Braswell 1988)
The objective of this thesis is to present an analysis of all heat transfer paths from the
surroundings to the interior food compartments of the refrigerator under closed door
conditions Both experimental and numerical methods are used as a means to determine the
overall cabinet load as well as the load due to each pathway The study is focused on a
particular unit for practical purposes However the methods implemented may be applied
to any make or model to aid in the search for high efficiency cabinets
All loads determined in this study are strictly cabinet loads and not the loads seen by the
refrigerator system The thermal load on the cabinet is comprised of three main parts (i)
the load due to the one-dimensional heat transfer through the walls and doors to the food
compartments away froin the edges (ii) the load due to edge effects that is heat transfer
into the food storage compartments via paths around the perimeter of the cabinet aperture
and (iii) other miscellaneous sources
(11)
The determination of qlD is straightforward and is discussed in detail in Chapter 3 The
edge load must be broken down into several parts for examination
qedge = qwall + qdoor + qseal + qrnullon + qtubeave (12)
where
qwall heat input due to conduction along the wall steel flange
qdoo heat input due to conduction along the door steel flange
qseal heat conduction directly through the door seal
1
heat input due to conduction in the mullion region with the additional input from an anti-sweat heater
qtubeave heat input due to cabinet anti-sweat condenser tube averaged over the cycle time
heat input due to cabinet anti-sweat condenser tube
heat input due to conduction in the mullion region electric heater off
It is assumed that an electric anti-sweat heater in the mullion region is in use for the entire
cycle The test unit chosen for this study required this region to be heated almost
continually to eliminate condensation This load is represented by qmulloo in Eq (12)
The load qmulloff is due to heat conduction to the interior compartments at the mullion
region when the electric heater is off Although this value does not appear in the edge load
definition it is still important to detennine for sake of comparison with the value of
qmulloo The load due to the presence of an anti-sweat condenser loop around the aperture
of the cabinet is defmed as qtube Since this load is present for the on cycle only it must be
integrated over the cycle time to be included in Eq (12) hence the tenn qtubeave
The tenn qroisc is expressed as
qmisc = qfanave + qdefrostave + qcompave (13)
where
qfanave heat input from the evaporator fan averaged over the cycle time
qdefrostave heat input from the defrost heaters averaged over defrost cycle time
qcompave heat input from elevated exterior walls near the running compressor
Figure 11 is a cross sectional drawing of the door seal area of the test refrigerator
examined to detennine qwalI qdoor and~ The figure includes materials and their
properties taken from Incropera and Dewitt (1985)
2
400 ~I-I~ 065~
065 Only dimension that is different for the freezer
200
kltWIm-K)
Outer Steel Skin 540 312~ Polyurethane Wall Insulation 0027 0015- Inner Plastic Skin 015 009~
~ Rubber Gasket 03 017fm1I ~ ~ Glass Fiber Door Insulation 004 0023
All dimensions in millimeters
1 in= 254mm
Fig 11 Door Seal Region Cross Section
3
Figure 12 is a drawing of the mullion region cross section of the test refrigerator examined
to detennine ltlmullon and ltlmulloff
FREEZER
Freezer Gasket
Fresh Food Gasket
FRESH FOOD COMPARTMENT
Fig 12 Mullion Region Cross Section
The remainder of this thesis is devoted to the analysis of the closed door cabinet loads and
the experimental and numerical techniques used for their detennination
An experimental investigation of fumed silica as an alternative insulation for the refrigerator
is presented in Appendix A Although this appears to be a departure from the main topic
a relation exists The desire of higher efficiency requires a search for equal if not better
cabinet insulations that do not incorporate the use of ozone damaging CFCs Testing is
done to detennine the thennal conductivity and diffusivity of fumed silica for several
densities
4
2 LITERATURE REVIEW
The new energy standards imposed by the Department ofEnergy have sparked research in
the area of refrigerator efficiency and alternative refrigerants A study by Turiel and
Heydari (1988) focused on several ways to improve the efficiency of refrigerator-freezers
and freezers
Various classes for the study were chosen however the paper presents extensive results for
the most common variety a top-mounted automatic defrost refrigeratorfreezer The
design options considered were those changes that can be incorporated into the existing
refrigerator design Two types of improvements are noted (i) changes that increase energy
efficiency by decreasing the heat transfer into the cabinet and (ii) changes that increase the
efficiency by reducing auxiliary electricity use or improving the refrigeration system Type
(i) changes include Foam insulation substitution increased insulation thickness double
door gaskets improved foam insulation evacuated insulation panels and reduced heat load
of through-the-door feature Type (ii) changes include High efficiency compressor
substitution adaptive defrost fan and fan motor improvement anti-sweat heater switch
increased evaporator surface area hybrid evaporator enhanced heat transfer surfaces
mixed refrigerants improved expansion valve fluid control valve two-compressor system
use of natural convective currents and location of compressor condenser and evaporator
fan motor
Turiel and Heydari used a model developed by Little (1982) to carry out the energy use
simulations This model is a steady-state energy use simulation which computes the heat
leakage to the cabinet and then determines the energy needed to maintain the interior
ambient temperatures dictated by the OOE test procedure Turiel and Heydari present the
energy consumption figures for a 18 cubic foot top-mounted automatic defrost
refrigeratorfreezer as a baseline case They find that 74 of the total energy is accounted
for by the compressor 11 is for the anti-sweat heaters 10 is for the fans and 5 is
for the defrost heaters for a total of 947 kWhyr Also about 10 of the compressor
energy use is for the removal of internal heat generated by the evaporator fan motor defrost
heater and anti-sweat heaters
Several subsequent simulations were performed each time adding a design option that was
projected to improve efficiency The improvement levels were added cumulatively and
results were given on compressor run time heat leakage rate into the cabinet compressor
5
power demand at the operating point fan motor operating power for the evaporator and
condenser fans anti-sweat heater power and total daily and annual energy consumption
The goal here was to achieve by the last level of improvement the minimum energy
consumption that is technologically feasible One important fmding for all product classes
tested the highest efficiency was obtained by the use of evacuated panels in the planar
walls For example for the top-mounted automatic defrost unit the minimum energy use
was 515 kWyr
Finally an energy usevolume relation was developed from a linear regression obtained
from simulation results The resulting fit was shown as
Energy Use = Cl + C2Adjusted Volume
The constant Cl indicates the direct energy use to remove the cabinet loads associated with
the fan motors and heaters The slope C2 is an indicator of the rate of change ofenergy use
with a change in the adjusted volume This value reflects the rate of cabinet heat gain The
adjusted volume is the volume of the fresh food compartment plus 163 times the volume
of the freezer Turiel and Heydari produced a series of regressions for all of the defined
levels of design improvements allowing easy comparison at a specific adjusted volume
6
3 ONE-DIMENSIONAL WALL AND DOOR LOADS
In this section the overall steady cabinet load is calculated without considering the addition
of edge loading This load qlD is dermed as the heat transfer from the exterior
environment to the interior of the refrigerator under nonnal closed-door operating
conditions through four primary conductive paths (i) fresh food compartment walls (ii)
freezer walls (iii) fresh food door and (iv) freezer door In a later chapter the load due to
edge loading will be examined more closely
31 One-dimensional Heat Transfer Model
The steady conductive heat transfer through the walls of the refrigerator cabinet is
computed using a simple computer program written by Qausing (1983) This program
estimates inside and outside effective heat transfer coefficients using a flat plate natural
convection correlation Using these coefficients and the material properties and dimensions
of the wall insulation the one-dimensional heat transfer through the cabinet walls is
approximated for the fresh food and freezer compartments Figure 31 shows the
resistances and boundary conditions use in the model
Fig 31 Model Used To Calculate One-dimensional Load
7
The model provides flexibility for varying several parameters This allows application to
various types of refrigerator walls and doors Table 31 lists the input and output
parameters for the model The source code of the simulation along with the output for
completed runs are included in Appendix B
Table 31 One-dimensional Model Parameters
Input Parameters
To K (F) Room ambient temperature
Ti K (F) Interior ambient temperature
LiDs m (ft) WalVdoor insUlation thickness
kiDs Wm-K (Btuhr-ft-F) WalVdoor insulation thermal conductivity
A m2 (ft2) Cabinet surface area
Output
beo Wm2K (Btuhr-ft2_F) Exterior convective heat transfer coefficient
bei Wm2K (Btuhr-ft2-F) Interior convective heat transfer coefficient
hro Wm2K (Btuhr-ft2_F) Exterior effective radiative heat transfer coefficient
hri Wm2-K (Btuhr-ft2_F) Interior effective radiative heat transfer coefficient
qlD W (Btuhr) Heat transfer rate through specified section
32 Determination of Effective Heat Transfer Coefficients
The simulation developed automatically estimates the inside and outside effective heat
transfer coefficients This effective value is the sum of the convective and radiative
components which are defined below
The radiative heat transfer coefficients are computed iteratively using eqs (31) and (32)
assuming (i) gray walls at temperatures T wi or Two with emissivities poundi and Eo (ii) black
surroundings at Ti or To and (iii) walls can see surroundings only
(31)
(32)
8
The convective heat transfer coefficients are estimated from a flat plate natural convection
correlation developed by Clausing (1983) In the laminar regime (Ra lt 1()9) the Nusselt
number based on the film temperature is given by Eq (33)
NUf = 052 Ra4 (33)
For the turbulent regime (Ra ~ 109) the Nusselt number becomes
NUf = 009 Raf3 (34)
where in both cases
Tw+T_ Film temperature T f == 2
Lc == Vertical surface characteristic length g == Gravitational acceleration f3 == Thermal expansion coefficient v == Kinematic viscosity Tw == Vertical wall surface temperature T_ == Outsideinside ambient temperature
kf == Air thermal conductivity
The film temperature characteristic length Nusselt number and Rayleigh number will
have different values for the inside surface compared with the outside surface of the
cabinet Therefore the inside and outside convective heat transfer coefficients are
determined separately from eqs (35) and (36)
(35)
- NUfo kfohco - (36)Leo
9
33 Results
The four primary regions analyzed are (i) the fresh food compartment walls (ii) fresh food
door (iii) freezer walls and (iv) the freezer door The values for the input parameters
ltLins kins A) are taken from a full-size unit that is used for the experimental analysis
presented in Chapter 4 The room temperature is used for the model parameter To Also
the fresh food ambient Tee and the freezer ambient Tfz are substituted for Ti when
suitable in order to closely simulate real operating conditions The results are given in
Table 32
Table 32 Results From One-dimensional Load Analysis
Input
Section TooC eF)
Tj degC eF)
Lins m (ft)
kins Wm-K (Btuhr-ft-OF)
A m2 (fi2)
Fresh Food 21 4 0045 0027 242 Walls (698) (392) (0148) (0015) (2605)
Fresh Food 21 4 0040 0040 089 Door (698) (392) (0131) (0023) (958)
Freezer 21 -10 0056 0027 110 Walls (698) (-140) (0184) (0015) (1184)
Freezer 21 -10 0040 0040 034 Door (698) (-140) (0131) (0023) (366)
Output
Section hco Wm2-K cBtuhr-ft2-Fl
hro Wm2-K iJtuhr -ft2-Fgt
hci Wm2-K (Btuhr-ft2-F)
hri Wm2-K 1Btuhr-ft2-F)
qlD W (Btuhr)
Fresh Food 130 544 198 461 209 Walls (23) (96) (35) (81) (713)
Fresh Food 144 542 218 463 117 Door (25) (95) (38) (82) (399)
Freezer 143 542 226 397 143 Walls (25) (95) (39) (70) (488)
Freezer 164 538 259 400 81 Door (29) (94) (46) (70) (276)
herro =687 Wm2 K (121 Btulhr-ft2-OF) Total qlD =550 W herrrr = 670 Wm2 K (118 Btulhr-ft2_0F) (1876 Btuhr)
herrrz = 641 Wm2 K (113 Btulhr-ft2-OF)
The load for our operating conditions is 550 W (1876 Btuhr) Once again this quantity
does not reflect the total cabinet load on the refrigerator cabinet Edge effects are analyzed
in detail in the following chapters Another important result is the values for the effective
10
inside and outside heat transfer coefficients which are simply the sum of the convective
and radiative components The outside coefficient is heffo the fresh food coefficient is
heffff and the freezer coefficient is hefffz These numbers are used whenever film
coefficients are needed for computations
11
4 EXPERIMENT AL ANALYSIS
This section presents an experimental study performed on a full-size household
refrigerator In Chapter 3 we defined the load due to heat transfer through the walls and
doors of the cabinet as qlD The purpose of this experimental analysis is to quantify qwalh
qdoor qmulloff and Qrnullon and Qmisc Three types of tests are performed to accomplish
this task Descriptions of each are presented separately in the sections that follow
41 Temperature Profile Measurements
The refrigerator is instrumented with many thermocouples in various key areas to give
temperatures across the steel skin and to compare and verify the thermopile tests outlined
in the next section The four primary paths along the steel flange that are examined are the
wall-side fresh food door-side fresh food wall-side freezer and the door-side freezer
Five Type T 36 AWG thermocouples are placed along the skin for each path Figure 41
is a detailed drawing of the location of the thermocouples
Wall side TICs Door side TICs with 5 mm spacing with 5 mm spacing
Fig 41 Steel Skin Temperature Profile Thermocouple Placement
The wire leads are oriented so they run perpendicular to the temperature gradient so as to
reduce any effects of conduction along the wire to the bead The temperature data are fed to
the data acquisition system Each channel is a thermocouple input and is scanned at a rate
of 5 times a second The data are smoothed automatically by the software in blocks of 10
12
points for an average temperature every 2 seconds A full description of the data
acquisition and control system is provided in Appendix D
Data are collected for several runs to provide a good base to detennine average values since
the test conditions vary slightly from run to run To get a good measurement of the
temperature profIles along the steel flange the unit is shut off at the beginning of the run
and allowed to drift to quasi-steady conditions The presence of a large amount of thennal
mass (see Appendix C) within the refrigerator provides for a stable interior ambient
temperature during data collection The outer ambient is controlled by the room thennostat
which keeps the laboratory at a constant temperature to within plusmn1degC
Figure 42 is an example plot of a run that gives the temperature profIles along the steel
skin on the wall-side and door-side for the fresh food compartment
193
192
G 191 ~
i 19
middot5 189F
188
Run I iii --0 - Door Profile
~Imiddotmiddotmiddotmiddotmiddotmiddotmiddott 0 Wall Profue
i ~ i - - T =19273 - 001206x i i-- door i If ~
=-r~r==L~r=I ~ I +~~=~~~~~~~~~ middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot
Outdoor Ambient = 210 degC Fresh Food Ambient =48 degC
187-+----+----J------I----+---~
o 5 10 15 20 25
x (mm) 1 in= 254 mm
Fig 42 Steel Skin Temperature Plot for Fresh Food Compartment
The dashed line represents a linear least-squares fit for the door data and the solid line is the
corresponding fit for the cabinet wall data Each data point in the plot represents the
average temperature at that point over a period of time at quasi-steady conditions
Similarly Figure 43 is a plot of the temperature profIles for the freezer
13
186
184
a 182
~
i 18
5 178~
176
174
Run 1 t-- 1 1 --0 - Door Profde
P~P1 0 Wall Profile
- -LLl--=-+--shy- - Tdo = 18606 - O02354x i
or ~
=c==-rc1 1 ltb 1 ~
~~r--r- -r---shy0 5 10 15 20 25
x (mm) 1 in= 2S4mm
Fig 43 Steel Skin Temperature Plot for Freezer
A total of six separate runs were perfonned three for the fresh food compartment and three
for the freezer Plots for the other runs are located in Appendix E
From the figures above for the fresh food compartment the slope on the wall-side is
slightly steeper than the slope on the door-side In fact this trend is seen for all the runs
Therefore the heat conduction along the metal skin into the cabinet along the wall is
somewhat greater than that of the door For the freezer the slopes are nearly equal hence
the heat conduction along the wall skin and the door skin are nearly the same
42 Thermopile Testing
Another simple but important test is the use of a thennopile to measure the average
temperature difference at various locations on the steel flange regions of the unit Figure
44 is a schematic of the thennopile test set-up The thennopile is constructed from 36
AWG copperconstantan thennocouple wire
14
-
CopperConstan$t Junctions 285 mPt
IOmm
10mmThermopile
IOmm
Digital Multimeter
1 in= 254mm
Fig 44 Thermopile Test Apparatus
Five junctions are used for the fresh food compartment and three for the freezer The
junctions are mounted 10 mm (039 in) apart from one another along the steel skin beneath
the door seal Figure 45 is a detailed drawing of the lateral location of the thermopile
junctions
15
1 in =254 mm
Fig 45 Thermopile Placement
The thennopile provides an average temperature difference across the junctions The
output voltage must frrst be divided by the number of pairs of junctions and then translated
into a temperature difference using a referencing chart for the thennocouple wire Table
41 is a summary of the results from these tests The output voltages are read accurately to
within plusmn0002 mV The raw data and data reduction procedure are given in Appendix E
Table 41 Thermopile Output
Test Conditions Fresh Food aT Freezer aT TodegC
(OF) TffoC
(OF) Tfzoc
(OF) aTwallff degC
(Of) aTdoorffoc
(OFgt aTwallfzoC
(Of) aTdoorfzoC
(OFgt
1 210 (698)
48 (406)
-88 (162)
026 (047)
024 (043)
037 (067)
041 (074)
2 210 (698)
37 (387)
-87 (163)
027 (049)
026 (047)
038 (068)
040 (072)
3 208 (694)
37 (387)
-93 (153)
027 (049)
026 (047)
038 (068)
040 ( 072)
Average Values 209 (696)
40 (392)
-90 (158)
0267 (0481)
0253 (0455)
0377 (0679)
0403 (0725)
43 Thermocouple Drag Testing
One final technique applied is thennocouple drag testing This is a more qualitative method
to supply insight into what exactly is happening when the compressor is pumping wann
16
refrigerant through the anti-sweat tube that lines the perimeter of the cabinet aperture The
main objective of this test is not to give accurate temperature proftle infonnation but
instead to detennine the placement of the condenser tube This is needed as an input for
the numerical simulation of this region The reason that the temperature are not accurate is
the fact that the thermocouple is being dragged across a surface where good thermal contact
may not occur and significant energy may be generated Figure 46 is a schematic of the
apparatus used for drag testing
Power Supply
Data Acquisition System
Outer Metal Skin
Potentiometer
Inner Plastic Skin
Condenser Tube
Fig 46 Thermocouple Drag Test Apparatus
This device is quite simple yet very effective The type T 36 AWG thennocouple begins
at the interior boundary of the steel skin beneath the seal on the wall-side of the cabinet
The potentiometer is turned by hand moving the thennocouple oqtward along the skin
The temperature and location are stored simultaneously this way The thennocouple is kept
17
pressed against the steel flange by the seal The linear translation of the thennocouple is a
function of the output voltage Voutbull
s = 2mllT Vout (41)Yin
r =radius of potentiometer post =30 mm (012 in)
nT = total number of turns of potentiometer = 10
Vin = input voltage = 05 V
Vout = output voltage
Drag tests are run on the wall steel skin for both the fresh food compartment and the
freezer Runs are perfonned at four separate times the first being when the compressor
turns on Figure 47 is a plot of the drag proflles across the wall-side skin in the fresh food
compartment Figure 48 is a plot of the profiles in the freezer compartment The same
trends are generally seen for both regions The freezer profiles are simply shifted down in
temperature values as expected The temperature peak seems to move through time to
settle near the center of the flange region under the seal
31
30
29
G
i 28~
27
26~
25
24
23
e
Ji ~ i i i 1middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotlmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddoti~~
---l- Time 4
o Time 2 rr
i
0 5 10 15 20 x (mm)
Fig 47 Drag Profiles (Fresh Food)
18
26~--------+---------~-------4--------~
i ~
Time 1 24
22
20
18
16~~------+---------~-------4--------~
4 __
~~Time3
middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot_middotmiddot_middotmiddotimiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot
Outer Seal Edge o
o 5 10 15 20
x (mm)
Fig 48 Drag Profiles (Freezer)
44 Experimental Determination of qwall and qdoor
The results from the temperature profile and thennopile testing are used to detennine qwall
and qdoor according to the following defmitions
qwall = qwallff + qwallfz (42)
(43)
Where qwal1ff = heat conduction along wall-side fresh food compartment steel flange
qwallfz = heat conduction along wall-side freezer compartment steel flange
qdoorff = heat conduction along door-side fresh food compartment steel flange
qdoorfz = heat conduction along door-side freezer compartment steel flange
The trends derived from the fixed profiles exhibit generally good agreement with the
temperature differences seen by the thennopile For the fresh food compartment the
thennopile displays a slightly larger AT than what is seen in the profiles and both give a
19
slightly larger temperature difference for the wall-side compared with the door-side For
the freezer the temperature differences match closely on the wall-side however the doorshy
side AT is shown to be somewhat less than the wall-side AT for the fIXed thennocouple
measurements where the opposite is seen from the thennopile The worst discrepancy is
on the order of 10 and is probably due to the fact that the thennopile gives an average temperature difference at several vertical locations on the wall whereas the other method is
at one vertical location only
Since the thennopile produces an average temperature difference across the steel skin its
output is used to detennine the heat flux into the cabinet The refrigerator casing is being
used as a heat meter Thus the flux along the skin in the fresh food compartment on the
wall-side is
kmiddot ATwallffqwallff = m (44)
Ax
The load qwallJf is Eq (44) multiplied by the cross sectional area This area is the
thickness of the steel casing multiplied by the perimeter that is exposed to the room
ambient This perimeter varies for each of the two paths that comprise qwall and the two
paths that comprise qdoor The other cabinet loads are computed in a similar way and are
given in Table 42 The details of these values are given in Appendix E
Table 42 Experimental Determination of qwall and qdoor
Section Load W (BtuIhr)
qwallJf 28 (96)
qwallJz 21 (72)
qwall 49 (168)
qdoorff 33 (112)
qdoorJz 33
1112)
qdoor 66 (224)
20
45 Experimental Determination of qmulloff
The region that lies between the fresh food compartment and the freezer is called the
mullion The front portion of the mullion is covered by a thin steel face plate to provide a
suitable interface for the door seal magnets In this section the load due to heat conduction
along the mullion steel skin into the freezer and fresh food compartment is detennined
based on the experimental data
The heat transfer rate qmulloff is sum of two parts The first component is the heat
conduction along the steel plate into the fresh food compartment and the second is the
conduction into the freezer
qmulloff = qmulloffff + qmullofffz (45)
Figure 49 schematically illustrates paths of these two components
FREEZER
FRESH FOOD COMPARTMENT
Fig 49 Heat Flow Paths in Mullion
21
Ten 36 A WG type T thennocouples are mounted from top to bottom across the steel face
plate Figure 410 shows the cross section of the plate and the location and numbering of
the thennocouples
FREEZER
1bennocouplesSteel Face (5 mm spacing from
Plate bottom edge)
Freezer Gasket
Fresh Food Gasket
10 50
FRESH FOOD COMPARTMENT
1 in =254 mm
Fig 410 Mullion Face Plate Cross Section
Data are gathered from the ten thennocouples when the unit is shut off and allowed to drift
to a quasi-steady ambient temperature A total of five runs were perfonned Figure 411 is
a sample plot of the quasi-steady temperature profile All other plots are contained in
AppendixE
22
116
Run 1 I 115 ICcIIIII114 iii t ~mull~ =12~7 - 00~654xa
~ 113
rrfIIJ~~If112i 5 )mullfz 1= 1081~ + OOdl25X 111111 ~
11 oo+-t--t-iH-+-lo-shyiii i i Room Ambient = 2184 degc
109 middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1middot Fresh Ambient = 381 OC
108
1 10
I I I I I Freezer Ambient =-832 degc
2 3 4 5 6 7 8 9
TIC
Fig 411 Mullion Temperature Profile
The plot also shows two linear equations These represent linear fits to each side of the
peak temperature at TIC 7 The slopes (shown in degCmm) are used to detennine the heat
conduction to each compartment by eqs (46) and (47)
lmulloffff = km A (aT) (46)ax offff
qmul)offfz = km AIll) (47)ax offfz
The cross sectional area is the product of the face plate thickness (10 mm 0039 in) and
the length of the mullion (717 mm 2825 in) The average slopes from all five runs are
used to detennine qmulloffff and qroullofffz The results are given in Table 43
23
Table 43 Experimental Results from Mullion Analysis
Load W (Btuhr)
09qmullofUz (31)
07qmulloffff (24)
16qmuIlorr (55)
46 Experimental Determination of qmullon
In this section the load due to heat conduction along the mullion steel skin into the freezer
and fresh food compartment when an anti-sweat heater is on is experimentally determined
The test unit is equipped with an electric anti-sweat heater to eliminate condensation in the
mullion region The heater is installed on the back side of the plate and may be switched on
manually when needed It is a wire resistor type rated at 10 watts
The heat transfer rate qmullon is composed of two parts The first component is the heat
conduction along the steel plate into the fresh food compartment and the second is the
conduction into the freezer similar to ~ul1off
qmuIlon = ~ullonff + qmuIlonfz (48)
The location of the wire heater and the heat transfer paths are shown in Figure 412
24
FREEZER
qmullonfz
qmullonff
FRESH FOOD COMPARTMENT
Fig 412 Electric Heater Location
A series of tests are perfonned while the heater is on and the refrigerator is cycling
nonnally Three runs are done at each of three separate locations along the mullion
laterally (i) LEFT dermed as 180 mm (71 in) from the left-hand side of the unit (ii)
RIGHT 180 mm (71 in) from the right-hand side of the unit (iii) CENTER at center of
the mullion Figure 413 is a plot of the temperature profile across the face plate when the
heater is on for a specific test run The plots for all other runs are provided in Appendix E
The plot shows two profiles These represent the upper and lower limits as the unit cycles
The upper limit occurs just before the compressor turns on while the lower limit is at the
point in time just before the compressor shuts off At all times in between the profile
oscillates between the two limits maintaining nearly the same shape Once again a linear
fit is applied to the data on the fresh food side and the freezer side
25
30 iii imiddot iii i
29
28
27
Run 1
T mu
ill~~ 11 f = 26707 + 010776x Tmu11ff = 3128 - 00793x
Z +_ a 26~
I ~
middotmiddotmiddotbull-middotbullimiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotimiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotimiddotmiddotmiddotimiddotmiddot
24
25
e 23~ =H-T+H~i=i=
iimiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotimiddotmiddot T 11 ff = 27435 - 009504x 22 Tmullfz =21865 + 01l786x I m~ iii
21 -lmiddotmiddotmiddotmiddotmiddotmiddotmiddot-tmiddot Upper Limlt 0
20 middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotjmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotimiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddott 0 Lower Limit
19
0 1 2 3 4 5 6 7 8 9 10
TIC I
Fig 413 Mullion Temperature Profile With Heater On (Center)
Heat fluxes are computed identically to the method in Section 45 using the average slopes
from all nine runs The minimum value occurs just before to compressor turns on while
the maximum value occurs just before the compressor shuts off during normal cycling
The load is averaged over the cycle time which is approximately 50 for the test unit and
laboratory conditions The results are given in Table 44
Table 44 Experimental Results from Heater Analysis
Lower Profile Average W
(BtuIhr)
Upper Profile Average W
ffituhr)
qmullonfz 73
(249) 53
(181)
qmullonff 23 (78)
26 (89)
96 (32 7)
79 (270)
qmullon 88
300)
26
47 Determination of Qmisc
The load qoisc is comprised of three main parts The first is the load due to the evaporator
fan motor The fan that moves cool air in the cabinet also adds a thennalload Fans of this
type in use range from 8 - 16 watts The fan of our test unit is rated at 92 watts This
value must be integrated over the cycle time The cycle time for the unit is approximately
50 for the test conditions Thus the value of qfanave is 46 watts
The load qdefrostave is not determined experimentally Instead an estimate is obtained from
a similar study done by Turiel and Heydari (1988) This value is 5 watts which is an
average of the defrost heater input over the defrost cycle The defrost cycle can range from
10 - 12 hours of compressor run-time
The fmalload qcompave is detennined by measuring the cabinet surface temperature at the
region surrounding the compressor and computing the heat transfer locally The value is
found to be 2 watts Table 45 summarizes the results
Table 45 Miscellaneous Loads
Load W CBtuhr)
46 qfanave (15middotU
50 qdefrostave _07Ql
20 qcompave (68)
116 Qmisc (395)
27
s NUMERICAL SIMULATION
In this chapter a two-dimensional numerical model which is used to simulate the steadyshy
state heat transfer in the wall near the door seal is discussed The results from the model
include a computation of qwallff qwallfz and the complete temperature distribution across
the section The model is also used to estimate the additional cabinet load due to the
presence of an anti-sweat condenser tube embedded beneath the outer casing that runs
along the perimeter of the unit A separate model is presented which is used to simulate the
two-dimensional heat transfer across the door seal cross section The results are used to
determine qseal
51 Wall Model
A finite-difference technique is used to approximate the steady-state temperature
distribution in the wall section The technique is applied to solve the governing steady
two-dimensional heat conduction equation (assuming constant conductivity with no
generation)
(51)
Equation (52) is the basic fmite-difference representation of the conduction equation in a
homogeneous medium of constant conductivity with no heat generation (White 1988) In
Appendix F a complete list of all the model difference equations is provided
2(1+(3)Tij = (3Tij+l + Ti+lj+(3Tij-l + (3Ti-lj (52)
where (3 = (llxlly)2
28
Figure 51 is a sketch of the model representation of the refrigerator wall at the door seal region The dimensions shown are flexible parameters in the model The model allows for
slight changes in the geometry as well as changes in mesh size in both x and y directions
However the mesh size must remain uniform across the section
s5 s6
sl
Fig 51 Wall Heat Conduction Model Sketch
For each of N unknown nodal temperatures N simultaneous linear algebraic equations are obtained for N unknowns If N is large as is the case for this simulation an iterative
technique is preferred to solve the system ofequations A Fortran program has been
written to carry out the finite-difference iteration A copy of the code is given in Appendix
F A simple Guass-Seidel technique is employed for the differencing iteration At each
iteration an energy balance is done for the entire section In theory this balance should be
29
zero (heat entering) = (heat leaving) The iteration is continued until the difference
between heat entering and heat leaving is equal to 1 of the total heat entering the section
Table 51 defines the input parameters for the simulation
Table 51 Wall Simulation Input
Code Parameter Definition
To C (F) Exterior surrounding ambient temperature
Ti C (F) Interior ambient temperature
lan Wm-K (Btuhr-ft-F) Steel skin conductivity
kp Wm-K (Btuhr-ft-F) Plastic skin conductivity
kins Wm-K (Btuhr-ft-F) Wall insulation conductivity
heffo Wm2-K (Btuhr-ft2-F) Outside effective heat transfer coefficient
hefti Wm2-K (Btuhr-ft2-F) Inside effective heat transfer coefficient
dm mm (in) Steel skin thickness
dp mm (in) Plastic skin thickness
dx mm (in) Mesh size x direction
dy mm (in) Meshsizeydirection
sl mm (in) Wall width
s2 mm (in) Wall length
b mm (in) Effective Perimeter
s3 mm (in) Seal indentation
s4 mm (in) Seal width
s5 mm (in) Depth of steel skin into cabinet along seal boundary
s6 mm (in) Width of plastic skin along seal boundary
The model assumes that the boundary that lies along the door seal is adiabatic This allows
the separation of the wall section from the rest of the geometry in this region The seal and
door can then be treated separately later A simple calculation is done to validate this
assumption
30
Steel Skin (Refrigerator wall)
Seal (k = 02 Wm-K)
Fig 52 Non-adiabatic Door Seal
A 2 degC temperature difference AT is imposed across the seal This is a slight overshy
estimate based on the experimental data An estimate of the conductive heat flux is
determined from Eq (53)
ATqerror=k- (53) Ax
qrror =02 Wm-C o~Cm =20 Wm2
The heat flux ql for the fresh food compartment is determined in Appendix E to be 14418
Wm2 Therefore qerror represents approximately 13 of the total flux Hence this
term is neglected in this study
Two other possible sources of error are associated with the fmite-difference technique itself
(Ozisik 1980) The fIrSt is called truncation error and arises from the discretization of the
second-order derivative in the steady conduction equation The second is referred to as the
round-offerror which is due to the fact that numerical calculations are carried out only to a
finite number of decimal places Repeated solution with smaller increments shows that the
truncation error is negligible The precision of the energy balance is evidence that the
round-off errors are negligible
31
S2 Wall Simulation to Determine qwall
The finite-difference model is used to detennine the wall-side heat transfer along the steel
skin However more valuable information is yielded from the simulation The nodal
temperature distribution is detennined which gives insight into the direction and magnitude
of heat fluxes throughout the section The fresh food compartment and the freezer are both
simulated to detennine qwallff and qwallJz respectively Table 52 is the list of the values
used for the model input parameters for both cases
Table S2
Code Parameter
To C eF)
Ti C eF)
kIn Wm-K (Btuhr-ft-F)
kp Wm-K (Btuhr-ft-F)
kins Wm-K (Btulhr-ft-F)
heffo Wm2-K (Btuhr-ft2_F)
heffi Wm2-K (Btuhr-ft2-F)
dm mm (in)
dp mm (in)
dx mm (in)
dy mm (in)
sl mm (in)
s2 mm (in)
b mm (in)
s3 mm (in)
s4 mm (in)
s5 mm (in)
s6 mm (in)
Input Values
Fresh Food 210 (698) 40
(392) 540 (312) 015 (009) 0027 0015t 687 (121) 670 (118) 065
(0026) 25
(0098) 225
(0088) 25
(0098) 450
(1772) 2000 (7874) 2960
(11653) 225
(0088) 2025 (0797) 225
(0886) 2025 (0797)
32
Freezer 210 (698) -10
(140) 540middot (312) 015 (009) 0027 (0015) 687 (121) 641 (113) 065
(0026) 25
(0098) 28
(0088) 25
Jo098) 540
(2125) 2000 (7874) 1580
(6220) 28
(0110) 196
JO772) 224
(088t) 288
(1134)
The output from the simulation includes the entire nodal temperature field heat fluxes at
each node along the centerline heat fluxes from node to node along the steel skin beneath
the door seal and the value for qwallff and qwallcz These heat transfer values and the
nodal temperature distribution are listed in Appendix F
The quantities qwallff and qwallcz are determined by computing the heat fluxes from node to node along the centerline of the section subtracting the one-dimensional flux and then
multiplying by the cross sectional area for that node and summing to give the total heat
transfer rate The primary results are shown in Table 53
Table 53 Wall Simulation Results
Section
The temperature distributions are shown in the following two figures Figure 53 shows
the temperature contour for the fresh food results Figure 54 is the same plot for the
freezer results
Since the geometry of the refrigerator door is similar to that of the wall along the edges the
heat leakage to the food compartments along the door flange can be approximated as being
roughly the same as qwall This approximation of qdoor is a good means of estimating the
two prime contributors to the edge loss for various different refrigerators which may have
slightly different geometries as well as different material properties
33
i
3875
3625
TemplaquogtC)
-e
11111
20
18
16 3375
g 3125 14 -5 2875 ~ 122625 ~
2375~ 102125~
1875 8
1625
1375 6
1125
875 4
625
375
SteeVPlastic Liner Interface
Fig 53 Fresh Food Wall Temperature Distribution
34
i 4875
4625
4375
4125
3875
3625
3375 -
3125e g 2875
2625 ~ 2375 ~ 2125c (I)
1875 ~ 1625
1375
1125
875
625
375
125
Fig 54 Freezer Wall Temperature Distribution
Temp(OC)
20
15
10
5
0
-5
-10
35
53 Wall Edge Simulation to Determine qtube
The wall simulation is modified to include a constant temperature node placed beneath the
steel flange to represent the presence of an anti-sweat condenser tube The simulation is
perfonned for the specific conditions that are typical of the test unit as well as a range of
lateral tube locations For the test refrigerator the tube is located as shown in Figure 55
and is at 35degC (95 OJlt)
Outer Steel Skin
14625 mm 1
Inner Plastic Liner
Fig 55 Tube Location for Simulation
The quantity qtube is detennined by taking the fluxes along the vertical line to the left of
the tube subtracting the one-dimensional flux and then multiplying by the cross sectional
area for that node and summing to give the total heat transfer rate Again the fresh food
compartment and the freezer must be simulated separately to produce a total governed by
Eq (54)
(54)
Program output for the fresh food and freezer simulations is given in Appendix F Table
54 summarizes the results from the model
Table 54 Wall With Condenser Tube Simulation Results
Section Load W iBtubrl
qtubeff 46
(157)
qtubefz 28 (96)
qtube 74 (253)
qtube8ve (ave for 50 cycle time)
37 (126)
36
-I i c IJ
~
r 4875
4625
4375
4125
3875
3625
3375
3125
2875
2625
2375
2125
1875
1625
1375
1125
875
625
375
125
TempfC)
SteeVPlastic Liner Interface
35
30
25
20
15
10
5
Fig 56 Fresh Food Wall Temperature Distribution Including Warm Anti-sweat Tube
37
TempfC)4875
4625
4375
4125
3875
3625
3375 - 31258
2875g 2625fo 2375
3 2125 d vI 1875
~ 1625
1375
1125
875
625
375
125
SteeVPlastic Liner Interface
Fig 57 Freezer Wall Temperature Distribution Including Warm Anti-sweat Tube
38
40
30
20
10
0
-10
The heat fluxes at each node along the vertical line to the left of the tube are also computed
by the simulation This value quantifies the amount of heat that is moving toward the outer
boundary and is used to determine the percentage of heat entering the cabinet For the test
refrigerator this value is 18 for the fresh food compartment and 24 for the freezer
Several more simulation runs were done to find the effect of lateral placement of the tube on
the overall heat transfer and the percentage of heat entering Figure 58 and Figure 59
show the trends that are found
-~ a tUbe ~middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotlmiddotmiddotmiddot=middotmiddot=pmiddotmiddotmiddot=middot-1- =1
middot middot middoti middot middotmiddotmiddotmiddotmiddotmiddotmiddotmiddot bull middotmiddotmiddot i middotmiddotmiddotmiddot middotmiddot middotmiddot ~ middotmiddot
middotmiddotrmiddot-rmiddot 0 lwbeff middotlmiddotmiddot~middot Gmiddottmiddotmiddot9middotlmiddot
i i -0- lwbe i middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotimiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddot fz tmiddotEimiddotmiddot ~G- -~ -q- -
0 5 10 15 20 25 x(mm)
Fig 58 Load Due to Condenser Tube for Various Tube Placements
8
~ - 7
50
a 6
~ 5
~ en 4 ~
pound ~ 3
2
- 26
~ a 24
middots bO
pound 22c ~
~ 20
a = 18sect ~
16 0 5 10 15 20 25
x (mm)
Fig 59 Percentage of Heat Entering Cabinet for Various Tube Placements
39
54 Door Seal Simulation to Determine qseal
Another model is developed for the two-dimensional heat transfer through the door seal
This model is very similar to the one created for the wall section Once again a fIniteshy
difference technique is utilized to detennine the temperature distribution at steady-state
conditions Even though the cross sectional geometry of the seal is simplifIed to a square
with a hollow square with a centrally located cavity no closed-form solution can be
applied Therefore a simulation is needed
The fInite-difference representation of the two-dimensional steady Eq (55) using central
differencing is given by Ozisik (1980)
Ti-lj - 2Tij + Ti+lj + Tij-l - 2Tij + Tij+l = 0 (55) Ax2 Ay2
For this model a square mesh is applied reducing Eq (55) to
Ti-lj + Ti+lj + Tij-l + Tij+l - 4Tij = 0 (56)
x
Fig S10 Seal Simulation Mesh Layout
40
The nodes along the vertical surfaces at x=O and x=20 are subject to the convective
boundary conditions and governed by Eq (57) and Eq (58) respectively
2~xheffol 2~heffo2Ti+lj + Tij-l + Tij+l - (4 + k TiJ = - k To (57)
seal seal
2~heffffl 2~heffff2Ti-lj + Tij-l + TiJ+l - (4 + kseal Tij = - kseal Tff (58)
The nodes along the top and bottom outside surfaces are held at the prescribed temperature
profIles which are detennined from experimental data (see Section 41) The interior nodes
are subject to radiant e~change among themselves and conduction through what is assumed
to be stagnant air A closer look at the model of the hollow interior of the seal is shown in
Figure 511
Fig 511 Seal Cavity Mesh Details
Each interior node corresponds to a single gray surface with assumed emissivity of 09
Viewfactors for all surfaces are computed automatically before the iteration begins For
each iteration the effect of radiation within the enclosure is taken into account by updating
surface radiosities Jij Thus for nodes on interior surfaces an extra tenn is added to the
governing difference equation (Eb is the blackbody radiation)
41
~(J - Eb )1-pound IJ lj
A code written in Fortran is used to perfonn Guass-Seidel iteration of the difference
equations to compute the temperature distribution at mesh nodes (Code listing in Appendix
F) Once again convergence is based on an energy balance applied to the entire section
The iteration is continued until the difference between heat entering and heat leaving is
equal to 01 of the total heat entering the section Table 55 lists the input parameters
used in the model The fresh food compartment and the freezer compartment are simulated
separately
Table 55 Seal Simulation Input
Code Parameter Fresh Food Freezer
Number of nodes along outside edge 20 20
Number of nodes along inside edge 6 6 1 1Lx = fly mm (in) (0039) (0039)
210 210Outdoor ambient temperature degC (oF) (698) (698) 150 105Indoor local ambient temperature degC COF) 590J j509)
Outdoor heat transfer coefficient W m2-K 687 687 (121) (121)(Btuhr-ft2-F)
Indoor heat transfer coefficient Wm2-K 670 641 (118) (113)(Btuhr-ft2-F)
Gasket interior surface emissivity 09 09 03 03Gasket conductivity Wm-K (Btuhr-ft-F) (0173) (0173)
Wall-side Temperature Boundary 1905 - 1977x 1813 - 3475x Condition degC Door-side Temperature Boundary 1913 - 1384x 1852 - 2341x Condition degC
42
The load results are summarized in Table 56 below The program output is listed in
AppendixF
Table 56 Seal Simulation Results
Load W Section (BtuIhr)
10 Qsealff (34)
ljQsealfz (Sn
25qseal (85)
The steady-state temperature distribution is shown in the figures below Figure 512 is the
fresh food simulation and Figure 512 is the freezer simulation The direction of the heat
flow through the section is easily seen from these plots
43
Wall-side Boundary Temperature (C)
~~
I 20
195
i 19t 0
8 ~ 1859 -- ~
isis ~ ampJ gtshy 18 ~
11 ~ S ~ 175~
~ 17
165
x(mm)
Door-side Boundary
Fig 512 Seal Temperature Distribution (Fresh Food)
44
Wall-side Boundary Temperature (C)
Ii 19
185
18i f IQ 5 IQ
175-is-is I s 17j ~
5e 0C= 165
~ ~ 16
155
x(mm)
Door-side Boundary
Fig 513 Seal Temperature Distribution (Freezer)
45
6 DISCUSSION OF RESULTS
The heat transfer values detennined from the experimental analysis and the numerical
simulations are the various components that embody the cabinet load on the refrigerator It
is important to separate cabinet loads from system loads The system load can be thought
of as the total electrical energy consumption of the unit It has four basic components (i)
the compressor (ii) fans (iii) anti-sweat heaters and (iv) defrost heaters The first two
components the compressor and fans are the cost of removing heat from the cabinet This
amount of heat is equal to the cabinet load divided by the COP of the system The typical
energy consumption is shown schematically in Figure 61
System Load (Energy Consumption)
Defrost Heater (averaged over time
cycles every 10-12 hours of compressorrurt-time)
TuneCycle
Fig 61 Refrigerator System Load Graph
In a study done by Turiel and Heydari (1988) the compressor and fans accounted for 84
of the total system load for an 180 cubic foot top-mounted refrigerator Staley (1992)
found this value to be 86 for a similar unit Both of these studies used system analysis to
determine these numbers The energy consumption of the components were monitored
during operation The energy consumption of our test refrigerator can be determined in a
reverse manner from the cabinet load data If a COP of 1 is assumed the test refrigerator
46
compressor and fans accounts for 86 of the energy consumption to cool the cabinet This
compares favorably with the fmdings of Turiel and Heydari (1988) and Staley (1992)
Figure 62 is a schematic of the cabinet loads One possible load that is not included in the
figure is the heat input associated with the defrost drain tube that runs through the back
wall However this term is probably small relative to the other contributors
Cabinet Load
qseal qdoor
qwall
qmullon
qdefrostave
Fig 62 Cabinet Loads Graph
All the loads are determined in this study from either experimental measurements
numerical simulations or both Most of the loads are quasi-steady that is they do not
fluctuate significantly over the cycle time of the refrigerator There are four loads shown in
Figure 61 that are cyclical in nature The three loads that appear only while the
compressor is running are qcomp qfarb and qtube Also the refrigerator is subjected to a
load every time ice build-up is removed by the defrost heaters This load is averaged over
its own cycle time and shown in the graph as qdefrostave
47
61 Comparison of Simulation Results with Experimental nata
The majority of the cabinet loads are detennined from experimental data with the exception
of qseal and qtube The wall and door flange loads aremiddot also found from the numerical
simulation (see Chapter 5) The two-dimensional model detennines the wall-side heat
transfer along the steel skin into the food compartments No model is available to directly
detennine the heat transfer on the door-side However since the flange geometry on the
door-side is similar to the wall the value for qwall is considered to be a good estimate for
qdoor Table 61 gives these values determined from experimental measurements and the
simulation
Table 61 Comparison of Simulation and Experimental Values for qwall and qdoor
Experimental Result W Simulation Result W (BtuIhr) (BtuIhr)
qwallff 28 (96)
28 (96)
qwallz 21 (72)
27 (92)
qwall 49 (168)
55 (188)
ldoorff 33
(112) 28 (96)
qdoorfz 33
(112) 27 (92)
qdoor 66 (224)
55 (188)
The model predicts qwall to within 57 of the experimental value The agreement of the
estimate of qdoor with the experimental value is within 90
Some of the shortcomings in the model used in this investigation are
(i) Only the wall is modeled Ideally the entire region should be considered including the
door and seal (see Figure 11)
(ii) The flange geometry is simplified The steel casing skin in the flange region may bend
in more complex ways Also the plastic liner varies in thickness near the door seal
(iii) The mesh must be unifonn There is no means to vary how fme the mesh can be The
ideal situation would be to have a fine mesh near the edges and a course mesh far from the
seal
48
62 Mullion Analysis
The single largest edg~ load is found in the mullion section (329 of qedge and 94 of
qtol) This load is due to the electric anti-sweat heater installed on the backside of the face
plate The heater is rated at 10 watts and approximately 88 of that input enters the
interior of the cabinet as a thennalload This is probably due to the small surface area
exposed to the room and the low amount of convective heat transfer in the channel between
the fresh food and freezer doors With the heater on 88 watts is measured enter the food
chambers With the heater off only 16 watts enters the interior The addition of the
heater increases the mullion load 55 times Generally it is not necessary to use the
mullion heater at all times However for the test environment the heater nearly all the time
to eliminate sweating under the laboratory conditions
63 Seal Analysis
The heat conduction directly through the seal accounts for the smallest portion of the edge
loss (94 ofqedge and 27 of qtol) The numerical model to detennine these values uses
a simplified representation of the complex cross sectional geometry of an actual door seal
The various air pockets are reduced to a single hollow void There is no experimental data
to verify the model However the numbers and trends resulting from the simulation are
reasonable
64 Anti-sweat Condenser Tube Analysis
Thennocouple drag tests were perfonned to give insight into the nature of the temperature
profIles at the wall steel flange with the presence of an anti-sweat condenser tube The wall
heat transfer simulation model was modified to include the effect of this tube The heat
conduction to the interior increased by 76 at the wall flange region The amount of
additional loading due to the tube depends on several parameters location of the tube
temperature of the circulating refrigerant and local wall geometry Although the model is
flexible enough to handle vari01~S temperatures and limited geometrical changes only the
influence of tube position was investigated As the tube is moved towards the interior the
load increases For the test refrigerator about 20 of the heat flow was directed to the
interior compartments primarily along the steel skin
49
6S Overall Cabinet Load
The overall cabinet load is defined as a sum of three parts
(61)
The edge load is
qedge = qwall + qdoor + Qseal + Qrnullon + qtubeave (62)
where
qwall
qtubeave
heat input due to the conduction along the wall steel flange
heat input due to the conduction along the door steel flange
heat conduction directly through the door seal
heat input due to conduction in the mullion region with the additional input from anti-sweat heater
heat input due to cabinet anti-sweat condenser tube averaged over the cycle time
heat input due to cabinet anti-sweat condenser tube
qmulloff heat input due to conduction in the mullion region electric heater off
The terms of Qrnisc are defined as
qmisc = qfanave + qdefrostave + qcompave (63)
where
qfanave heat input from the evaporator fan averaged over the cycle time
qdefrostave heat input from the defrost heaters averaged over defrost cycle time
qcompave heat input from elevated exterior walls near the running compressor
Table 62 presents the overall cabinet load analysis results
50
Table 62 Overall Cabinet Loads
Load W Load Btuhr Total
qlD 550 1876 591
qedge 265 903 285
Qwall 49155 167 188 53
Qdoor 66155 2251 188 71
Qseal 25 85 27
Qmullon 88 300 94
Qtubl ngt 37 126 40
qmisc 116 395 124
Qfanave 46 157 49
Qdefrost ave 50 170 54
qcomoave 20 68 21
qtot 931 3174 100
Simulation Results
All loads are detennined experimentally with the exception oflsea1 and qtubeave The
values for qwall and qdoor are detennined from both experimental data and numerical
simulations Edge loss per unit length along fresh food perimeter is 29 Wm (30 Btuhrshy
ft) the loss per unit length along the freezer perimeter is 44 Wm (46 Btuhr-ft) and the
loss along the mullion section is 123 Wm (128 Btuhr-ft) with the heater on and 22 Wm
(23 Btuhr-ft) with anti-sweat heater off
The largest single load is the one-dimensional conduction through the walls and doors
The edge load comprises 285 of the total a significant portion The largest edge load is
due to the electric anti-sweat heater that is installed in the mullion section The smallest
edge load is due to the heat conduction through the fresh food and freezer door seals The
losses at the wall-side and door-side flange regions account for 53 and 71 of the total
load respectively These could be considered together since the pathway of heat transfer is
very similar If that were the case the sum of qwall and qdoor would be the second largest
contributor to the overall cabinet load The influence of an anti-sweat condenser tube is
reflected in the value of qtubeave Although this additional load is larger than qwall it must
be integrated over the refrigeration cycle timewhich is 50 of the cycle time for the test
unit The tube boosts the heat transfer along the wall flange by 76
51
To round out the cabinet load three miscellaneous loads are considered The evaporator
fan motor produces a heat load within the cabinet which is considered to be equal to the
power rating of the fan The automatic defrost feature is another thermal load that is
cyclical appearing about every ten to twelve hours of compressor runtime The fmalload
is due to the elevated exterior skin temperature near the compressor when it is running All
three of these loads are averaged over their cycle times for comparison with other quasishy
steady loads As a total qmisc represents 124 of the overall cabinet load
Opportunities to decrease the one-dimensionalload are available The emphasis has been to
develop super-insulations to be installed in the refrigerators Some being considered are
vacuum panels aerogels and vacuum packed powder insulations The disadvantages of
this improvement lies within the need to develop a cost-effective technique for fabricating
and installing such technologies compatible with high-volume manufacturing Also edge
losses and panel connection losses must be minimized due to the difficulty in making a
panel the size of refrigerator interiors Reliability of the seal and perfonnance of the outer
envelope need to be ensured over a long period of time ie the expected life of the
product
The possibilities of reducing the loads along the edge of the refrigerator aperture are
somewhat less apparent One method of reducing quasi-steady heat conduction along wall
and door flanges is to raise the inside cabinet wall temperature by minimizing interior film
surface heat transfer coefficients This could be accomplished by the use of low-emissivity
surfaces on the interior walls or on sections nearest the edges The need for an anti-sweat
device for the perimeter is also eliminated supplying a two-fold savings by reducing the
cabinet ioad and the system energy consumption The need for an electric mullion heater
might also be done away with by the same means The drawback again would be to make
such modifications acceptable and cost-effective for manufacture
The remaining miscellaneous loads provide some chance for improvement If the
efficiency of the fans is increased the energy use of the refrigerator can be reduced The
option of moving the fan motor outside the cabinet leads to other problems The motor
shaft must pierce the wall providing another path for heat leakage Also frost built-up on
the shaft would be a costly and difficult problem to eliminate If the compressor and
condenser were located near the top of the refrigerator they can operate more efficiently
Heat can be more readily convected away eliminating the need for the condenser fan
(Turiel and Heydari 1988) Frost fonnation in the freezer varies significantly depending
52
on the ambient conditions and the freezer usage The defrost cycle could be made more
energy efficient with the addition of adaptive controls All of these improvements would
require redesign of the product and the manufacturing process This is a very expensive
alternative which would need to be justified by the associated energy savings
53
7 SUMMARY OF CONCLUSIONS
The following is a list of the important findings produced from this study
(i) The edge loading accounts for a significant portion of the total cabinet load For the
test unit used in this study an 18 cubic foot top-mount refrigerator this load was
approximately 30 of the total load The load includes losses along the wall and door
flanges conduction through the door seal mullion loading with an electric anti-sweat
heater on and additional thennal input from an anti-sweat perimeter condenser tube
(ii) The presence of an electric anti-sweat mullion heater boosts the mullion loading by
a factor of approximately 5
(iii) The presence of an anti-sweat condenser tube around the perimeter of the refrigerator
increases the wall flange load by approximately 75
(iv) The presence of the door air damt reduces the temperature difference across the door
seal to 35 of the temperature difference between the interior and exterior
environments
(v) The hypothetical elimination of the additional load due to the electric anti-sweat
mullion heater reduces the edge loading to approximately 22 of the total cabinet
load
(vi) The hypothetical elimination of the load due to the anti-sweat condenser tube reduces
the edge loading to approximately 25 of the total cabinet load Ifboth anti-sweat
devices were not needed the edge loading would be further reduced to only 17 of
the total
(vii) During the course of this investigation it was concluded that the experimental and
numerical methods developed are applicable to most refrigeratorfreezers that are
produced today
t The portion of the door liner that extends into the cabinet along the wall
54
REFERENCES
Braswell A 1988 Impact of CFC Regulations on the Air Conditioning and Refrigeration Industry International Jow-nal ofRefrigeration Vol 11 No6 p 385
Cabot Corporation 1987 CAB-O-SIL Fumed Silica Properties and Functions Tuscola n pp 12-15
Clausing A M 1983 Natural Convection Correlations for Vertical Surfaces Including Influences of Variable Properties ASME Jow-nal ofHeat Transfer Vol 105 No 1 pp 138-143
Incropera FP and Dewitt DP 1985 Fundamentals ofHeat and Mass Transfer Second Edition John Wiley and Sons New York
Ingersoll LR Zobel OJ and Ingersoll AC 1954 Heat Conduction with Engineering and Geological Applications McGraw-Hill Book Company New York
Little AD Inc 1982 Refrigerator and Freezer Computer Model Users Guide Cambridge Massachusettes
Micropore International Ltd Microtherm Thermal Insulation Worcestershire England Section 1
Nix GH Lowery GW Vachon RI and Tanger GE 1967 Direct Determination of Thermal Diffusivity and Conductivity with a Refined Line-Source Technique Progress in Astronautics and Aeronautics (Vol 20) Thermophysics ofSpacecraft an Planetary Bodies Academic Press New York pp 865-878
Nix GH Vachon RI Lowery GW and McCurry TA 1968 The Line-Source Method Procedure and Iterative Scheme for Combined Determination of Conductivity and Diffusivity Thermal Conductivity Proceeding of8th Conference
Ozisik MN 1980 Heat Conduction Wiley-Interscience Publishing New York pp 486-487
Staley D 1992 Personal Communication Graduate Research Assistant University of Illinois Urbana
Turiel I Heydari A 1988 Analysis of Design Options to Improve the Efficiency of Refrigerator-Freezers and Freezers ASH RAE Transactions Vol 94 Part 2
Van der Held EFM and Van Drunen FG 1949 Physika Vol 15 No 10 p 865
White PM 1988 Heat and Mass TranSer Addison-Wesley Publishing Reading Mass pp 145-160
55
APPENDIX A FUMED SILICA INVESTIGATION
A ~ 1 Introduction
Fumed silica is a micro-porous powder comprised of submicron particles of amorphous
silica bonded together in a cellular structure Several grades of silica are available offering
a selection ofdifferent grain sizes and chemical treatments Fumed silica is commonly used
to provide thickening thixotropy suspension and other related properties in liquid
systems In dry systems it is used to promote free flow frictionizing and anti-blocking
properties Thus it is a versatile additive in materials such as inks coatings adhesives~
and silicon rubber (Cabot Corporation 1987)
The thermal insulating properties of this material have been somewhat less widely applied
however fumed silica as an insulation displays some interesting properties Fumed silica
insulations are commercially available and have become a more popular material for certain
specific applications In this section the results of an investigation of the thermal
properties of one type of fumed silica is presented
A2 Thermal Properties
As an insulator fumed silica uses the microporous principle to reduce thermal conduction
to the theoretically lowest possible levels (Micropore International Ltd 1988) Most
conventional insulations rely upon voids normally occupied bj alt aS the meanS ot
minimizing heat transfer through the material Therefore it is important to maintain these
voids for maximum insulation Fumed silica is comprised of tiny spheres with diameters
of the same order of magnitude as the mean free path of the molecules in the air
Therefore when these spheres are packed closely together gaseous conduction and
convection are minimized The cell size is sufficiently small to keep convective currents
from forming and to trap gas molecules to rebound elastically thereby not imparting their
energy to slower moving molecules In addition solid conduction is minimized by the fact
that silica is a material with intrinsically low thermal conductivity These unique properties
make fumed silica an attraCtive alternative to conventional insulations
56
A3 Experimental Method
Thennal conductivity and thennal diffusivity are the properties detennined from our
experimental study Many methods exist for establishing the thennal properties of a given
substance Both steady-state and transient procedures are available The hot-wire method
is a the transient procedure used in this study
The practical form of the hot-wire method is given by Van derHeldand Van Dronen
(1949) who used it to detennine conductivities of liquids Nix et al (1967) elaborated to
give a method for the simultaneous detennination of both thennal conductivity and thennal
diffusivity Therefore it is possible to detennine both conductivity and diffusivity by
passing a known amount ofcmrent through a heater wire embedded in the test material and
recording the temperature at a point on the wire and at a fixed point from the wire over the
period of the test From the temperature history of the point contiguous to the hot-wire the
conductivity can be detennined directly From the temperature history of the point at a
fixed distance from the hot-wire the diffusivity may be computed Both procedures are
outlined in the following section
A4 Theory
The temperature at any point in an infinite solid containing a line heat source of constantshy
rate is a function of the position time from initiation the thennal conductivity of the
material and the magnitude of the source This is shown mathematically by Ingersoll et aI
(1954) The cylindrical temperature field is expressed as
T=~l- exp-x2) dx (Al)21tk x
II
In series fonn
(A2)T=~[-amp-lnp+L-L+L_ ]21tk 2 21 4middot2 63
57
where
q = Heat input per unit length of wire [W1m]
k = Thennal conductivity of the material [Wm-K]
a = Thennal diffusivity of the material [m2s]
t = Elapsed time from heat liberation [s]
r = Radial distance from line-source [m]
Ce = Eulers constant (05772157 )
The temperature change between two times tl and t2 is accurate to better than one percent if
the value of ~ is less than 016 for a point very close to the line-source
(A3)
Equation (A3) is used in this case to detennine the thennal conductivity since the
diffusivity a and the radial distance T no longer appear in the relation Therefore
knowing the temperature at two different times during the test gives the conductivity
directly given that the value of ~ remains small This is achieved by choosing a point very
near if not contiguous to the hot-wire itself In our study a graphical method is used to
detennine the conductivity If the temperature versus the natural logarithm of the time is
plotted a straight line should be seen whose slope is equal to q4nk
Once the conductivity of the material is detennined the diffusivity can be found by the
method proposed by Nix et aI (1968) The temperature at a fixed and known distance
from the hot-wire must be monitored over the time period of the test Now since ~ gt 016
the diffusivity does not drop out of Equation (A2) Rewriting Equation (A3) as
(A4)
where
~2 ~4 ~6 ]r(~)= [ -~-ln~+---+-- (A5) 2 211 4middot2 6middot3
58
therefore (A6)
Using the temperature at the fixed location as an input Equation (A6) can be solved iteratively by means of Newton-Raphson technique to find the parameter ~ and thereby
yielding the thermal diffusivity a
AS Test Apparatus
Figure A1 is a sketch of the test apparatus used to collect thermal property data This
device provides a wide range of silica densities for packed tests Each half of the apparatus
is packed separately to the same density and then pressed together sandwiching the heater
wirethermocouple assembly between them
Remove bottom plate and press together with right half
Insert heater wirethermocouple assembl)
Remove bottom plate and press together with left half
Compact both halves to same density
Fig AI Fumed Silica Test Apparatus
Prior to loading the unpacked silica into the test cylinders the mass is carefully recorded
Each test cylinder has graduated marks to allow the volume of the sample to be computed
The density is then computed from the measured mass and volume At higher densities it
59
is sometimes necessary to load and compact several times Figure A2 is a schematic of the
heater wirethermocouple assembly and the entire test facility
Switch
Ammeter
Power Source
Cylindrical Test Section
Thermocouple for Conductivity
Data Acquisition System
Thermocouple for Diffusivity
Fig A2 Fumed Silica Test Facility Schematic
The heater wire used for all tests is 30 A WG nichrome wire with a nominal resistance of 2214 Wm Both thermocouples are type T 36 A WG Once the test sample is in place
the switch is closed allowing cUITent to pass through the heater wire The heat input per
unit length of the wire is determined from
(A7)
where q = Heat input per unit length of wire [Wm]
I = The input cUITent [Amps]
R = Heater wire resistance per unit length [Wm]
60
Knowing the heat input per unit length the temperature contiguous to the heater wire and
the temperature at a fixed distance from the heater wire over the duration of the test eqs
(A3) and (A6) can be solved This yields the conductivity and diffusivity respectively
A6 Results
All results presented in this section are from tests petfonned with a material sample donated
by Cabot Corporations Cab-O-Sil Division The silica is an untreated sample EH-5 with
a bulk density of 25 Ibsft3 and a nominal particle diameter of 70 angstroms Several tests
are petfonned at various densities The thermal conductivity is determined graphically as described above while the diffusivity is determined using a Fortran code to pe~orm the
Newton-Raphson iteration also outlined in Section A4
A total of seven different bulk densities are tested Each test consists of three runs at three
different power levels The temperature history is recorded for both thermocouples
Figure A3 is a plot of the temperature for the duration of a typical test for unpacked silica
70~--~----+----r----~-----~----+----r
10001
middot middot middot o 05 Ampsmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddot o 04 Ampsi ~ i
I i I I i oo~ct 60 IIJatr-T50
1 LL~40
1 ~ 1 010 1 ltgtom
JPi i30 i 0I1 o 03 Amps 1 I I
20~--~----+----r----~-----~----+----r
-10 o 10 20 30 40 50 60 70 Time (sec)
Fig A3 Time vs Temperature for Unpacked Run
61
To graphically detennine the thennal conductivity the temperatme data must be plotted
against the natural logarithm of time Figure A4 gives this plot along with the equations
that represent linear curve-fits to the straight portion of each curve
70~----~--------+------+--------~----~----~--------+-----~
60 ~ =l-LL-~--o T ~ 86839 ~ 1376 ~(t) I
50 ---f--H-deg--tfjtshy ~ T =11108 + 97346 m(t)
40 IT_oroJ~-
30 middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotImiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotsectmiddotmiddotmiddotmiddotmiddotImiddotmiddotmiddotmiddotmiddotmiddotmiddot~middotmiddotmiddotmiddot109~~Q9 T= 18431~ + 493 ~(t) 0
~ e i i i
20~----~--------+------+--------~---------~~----+------r
05 1 15 2 25 3 35 4 45 In (time)
Fig A4 Natural Log Time vs Temperature for Unpacked Run
All three curves should yield the same conductivity for the sample The conductivity is
detennined from the following relation
k= 12R (A8)4n(slope)
Table AI gives the average conductivity for each density level This is the average for the
three input cmrents used These results are also shown graphically in Figure A5
62
Table AI A verage Fumed Silica Conductivity for Various Bulk Densities
est
1
2
3
4
5
6
7
0024
0023
0022 -~ ct 0021
~ e 002
~
0019
0018
0017
i
~i
I I I I Imiddotmiddotmiddot_middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotimiddot_middotmiddot middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotimiddot-middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot
1i111
~ ~ iii
_I_1_1_1
I I I I I middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot middotmiddotmiddotmiddotmiddotmiddotmiddotfmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddot -r-t-o-rldegoo---shy
25 3 35 4 45 5 55
Density (lbsff)
Fig AS Conductivity vs Bulk Density
From the temperature data collected from the second thennocouple the thennal diffusivity
is computed (see Section A4) This thennocouple lies 3 mm (0118 in) from the heater
63
wire The output from the diffusivity iteration is provided in Table A2 A graphical
representation is given in Figure A6
Table A2 Average Fumed Silica Diffusivity for Various Bulk Densities
Test
Average Diffusivity m2s (ft2Jhr)
1 210 x 10-7 (000813)
2 166 x 10-7 (000643)
3 159 x 10-7 (000616)
4 155 x 10-7 (000600)
5 153 x 10-7 (000592)
6 No Data Available
7 151 x 10-7 (000585)
00085 -+----+-----f----+----+----+--_+_
I
middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1 ~0008
I I I I ~
I middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotfmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot Tmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot ~ 00075
~-shyf i ~ ~ ~ i ++middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotfmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot0007 i iii
~ rn ~ ~ i i~
(jj bullbullbullbullbullbull1bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullJLbullbullbullbullbullbullbullbullbullbullj ~ 00065o ~ middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot0006
I I I 00055 -+----+-----f----+----+----f--_+_
25 3 35 4 45 5 55
Density (lbsff)
Fig AS Diffusivity vs Bulk Density
64
A7 Conclusions
The primary conclusion from this experimental study is the fact that the thennal insulating
properties of fumed silica powder increase as the bulk density of the material increases
Although this study presents a limited range of density values the trends that were
expected are seen to be true The conductivity values are expected to reach and even
surpass those of CFC-blown foams that are used in household refrigerators Further
testing is needed to provide data that supports this expectation In addition testing in this
study was strictly limited to a single variety of silica This particular type of silica is not
necessarily the best candidate for thermal insulation applications Silica powders are by
nature hydroscopic This affinity for water has adverse effects on its thermal insulating
properties However silica powders are now produced with a special treatment which
transforms the material into a hydrophobic material Therefore if these new materials
maintain the thermal properties and density trends of the hydroscopic type they become
even more preferred insulators Once again data needs to be obtained to support this
notion Fumed silica offers a competitive alternative to the existing CFC-blown foams
without the obvious environmental drawbacks It is completely inert recyclable and
reusable It also competes well when comparing cost values CFC-blown foams are
between 003 - 007 $ft2_R-Value whereas fumed silica powder are between 005 -025
$ft2-R-Value The discrepancies are close enough to merit true consideration
AS Thermal Diffusivity Newton-Raphson Iteration Source Code
program difsivty implicit none double precision condqtime(lOO)temp(lOO)guessradiusalpha
+ dif(lOO)sumavedifgcurrentmasslengthpi + density integer nikrun OPEN (2file=Oiffusivityoutlposition=rewind) OPEN (3file=Oiffusivityinposition=rewind) OPEN (4file=Oiffusivityout2position=rewind)
print Enter input current in amps readcurrent printEnter calculated conductivity in Wm K readcond print Enter thermocouple distance in meters readradius print Enter mass of sample in grams readmass print Enter compacted length of sample in em readlength print Enter number of timetemperature data points
65
c
readn 5 print enter initial quess for beta
readquess c
pi=31415927 q=currentcurrent2214 density=(mass1000)laquopi4)(003844)(lenqth100raquo
c c check to see if converqence will occur c print Enter data point l c print (time and temp with a blank separatinq the two) c readtime(1)temp(1) c call diffus(condqtime(1)temp(1)quessradiusalphaq) c printinitial q=q c if (abs(q) qt 05) then c qoto5 c endif c
do 10 i=1n read(3) time(i)temp(i)
10 continue c
print print Input Current= current print write(2) Input Current= current write (2 )
c sum=OO do 20 k=1n call diffus(condqtime(k)temp(k)quessradiusalphaq) print Diffusivity for data pointk =alpha write(2) Diffusivity for data pointk =alpha write(4) alpha dif(k)=alpha sum=sum+dif(k)
20 continue c
avedif=sumn c
print print print INPUT print Conductivity=cond Wm K print Heater Input=q Wm print Thermocouple Distance=radius m print- print OUTPUT print Sample Density=density kqm3 print Averaqe Diffusivity=avedifmiddot m2s
c write(2) write(2) INPUT write(2) Conductivity=cond Wm K write(2) Heater Input=q Wm write(2) Thermocouple Distance=radius m write (2 ) write(2) OUTPUT write(2) Sample Density=density kqm3 write(2) Averaqe Diffusivity=avedif m2s
c c
pause stop
66
end
subroutine diffus(condqtimetempguessradiusalphag) implicit none double precision condqtimetempbeta(100)radius
+ f1f2f1pf2ptempf2tempf2pggppialphaCe + signfactol integer jkmn
c Ce=5772157 pi=31415927 beta (1) =guess tol=l j=l
c c begin Newton-Raphson iteration to find beta and ultimately alpha c
while (tol gt 0001) c print betaj =beta(j)
f1=-Ce20 - log(beta(j)) flp=-l Obeta (j) f2=00 f2p=00
c c start loop to compute the summations for f2 and f2 prime
do 10 k=2162 m=k2
c this loop gives the factorial for the kth term fac=10 do 5 n=lm
fac=facn 5 continue
sign=(-1)laquok+2)2) tempf2=laquobeta(j)k)sign)(kfac) tempf2p=laquobeta(j)(k-1))sign)fac f2=f2+tempf2 f2p=f2p+tempf2p
10 continue
c c compute the value of G and G which are both functions of beta c these will be used to update beta in the Newton-Raphson iteration c where beta(n+1)= beta(n)- GG
g=laquo20picondtemp)q)-(f1+f2) gp=- (flp+f2p)
c print g=g c here we check to see if the convergence criterion suggested c by Nix is met for the initial beta chosen if not we must jump out of loop c if (j eq 1) then c if (abs(g) qt 05) then c printconvergence not satisfied c printtry a s~aller guess for beta c return c endif c endif c c update the value of beta and compute a tolerance value c that will be used to check for convergence
beta(j+1)=beta(j)-(ggp) tol=abs(beta(j+1)-beta(j))
67
j=j+1 c protect against infinite looping
if (j eq 100) then goto 101
endif repeat
c c if the iteration converges then compute the value for diffusivity
alpha=(10(40timeraquo(radiusbeta(jraquo2
c c
101 return
68
APPENDIX B ONE-DIMENSIONAL SIMULATION SOURCE CODE AND OUTPUT
B1 Source Code
CPROGRAM FrigWall--Steady-State Heat Conduction with Convective and CRadiative Heat Transfer from interior and exterior surfaces C Programmed by AM CLAUSING
LOGICAL SI DIMENSION RA(2)XNU(2)R(2)H(2)HR(2)TF(2)TW(2)DT(2) COMMON AXLWXLC(2)HC(2)T(2)XKWBETANMAXSIE(2)SIGMA
CDetermine- direction of output read and print input data NCASE=l
1 CALL DATAIN(NCASEIUOUT) NCASE=NCASE+1 QOLD=O TW(1)=T(1)+1(T(2)-T(1raquo TW(2)=T(2)-1(T(2)-T(1raquo
CCalculate wall resistance RW=XLWXKWA DO 3 N=lNMAX DO S J=12
CCalculate the radiative equivalent heat transfer coefficients HR(J)=SIGMAE(J)(T(J)2+TW(J)2)(T(J)+TW(Jraquo
C Calculate the film temperatures TF(J)=(T(J)+TW(Jraquo2
CCalculate the convective heat transfer coefficients CALL GASPT(lTF(J)RHOXMUXKCPGRBPRIER) DT(J)=ABS(TW(J)-T(Jraquo RA(J)=PRGRBXLC(J)3DT(J) IF(RA(J) LT1E9) THEN
XNU(J)=0S2RA(J)2S ELSE
XNU(J)=09RA(J) 3333 ENDIF H(J)=XNU(J)XKXLC(J) IF(HC(J) NE O) H(J)=HC(J)
CCalculate surface resistances R(J)=l(H(J)+HR(JraquoA
S CONTINUE CCalc~late total resistance heat flow rate and surface temperatures
RT=R(1)+R(2)+RW Q=(T(2)-T(1raquoRT TW(l)=T(l)+QR(l) TW(2)=T(2)-QR(2)
CCheck for convergence If solution has converged exit loop ERRQ=ABS(Q-QOLD)100Q QOLD=Q IF(ERRQLT OS) GOTO 7
3 CONTINUE 7 WRITE (IUOUT 101) Q ERRQ (H (J) HR (J) RA (J) XNU (J) TW (J) DT (J) R (J) RT
2 J=l2) 101 FORMAT( Q =F61 W10XERRQ =FS2 T12 hconvT22hradT33
2 RaT44NuTS2 TsurT62 DeltaTT72RRtotT10 [Wm2-KjT20 2 [Wm2-KjTS3 [KjT63 [Kj InsideF72F92E133F91 2 F101F91F113 OutsideF62F92E133F91F101F91F113) DO 9 J=l2 IF(HC(J) NE bull O) WRITE (IUOUT 103) J
9 CONTINUE 103 FORMAT( NOTE hconv(I1 ) was specified not calculated)
GOTO 1 END
69
C SUBROUTINE DATAIN(NCASEIUOUT) LOGICAL SI COMMON AXLWXLC(2)HC(2)T(2)XKWBETANMAXSIE(2)SIGMA DATA AXLWXKWXLCHCTENMAXSIGMA2990360245315 2 20277297 959510567E-8
CDefinition of NAM NAMELIST NAMAXLWXKWXLCHCETNMAXBETASI CHARACTER FNAME60CDATE9CTIME8 PARAMETER (IUIN=7)
CIF First Case Open Files Write Program Description and Date IF (NCASEEQ 1) THEN
WRITE (6 100) 100 FORMAT( TYPE NAME OF INPUT DATA FILE)
READ( (A) ) FNAME COpen input and output files
OPEN (7FILE=FNAME) REWIND 7
C OPEN (10FILE=Plots-FNAME) C WRITE(6122) Plots-FNAME C122 FORMAT( COMMA DELIMITED PLOTTING FILE IS A)
WRITE(6118) 118 FORMAT (T10 DIRECT OUTPUT TOT20 SCREENT36 Type 6
2 T20 OUTPUT FILET36 Type 8T20 PRINTERT36 Type 9) READ() IUOUT IF(IUOUTEQ8) THEN OPEN (8FILE=Answers-FNAME) WRITE(6120) Answers-FNAME
120 FORMAT( OUTPUT WILL BE WRITTEN IN FILE A) ENDIF CALL DATE(CDATE) CALL TIME(CTIME)
CWrite Program Description and Date WRITE(IUOUT102)CDATECTIME
102 FORMAT( Program FrigWallT60 Date A10 Version 8 August 1991T60 2 Time A9 Programmed by AMClausing) ENDIF
CRead and Write Input Data READ(IUINNAMEND=999) WRITE (IUOUT 104) NCASETXLCEXLWXKWA
104 FORMAT ( CASE NUMBER 12 2 Ambient Temperatures IK] InsideF616X OutsideF61 2 Characteristic Lengths 1m] InsideF626X OutsideF62 2 Surface Emissivities8X InsideF626XOutsideF62 Wall
Thickness 2 F63 mT27 ConductivityF63 Wm-K2x AreaF52 m2) RETURN
999 WRITE (IUOUT 199) 199 FORMAT ( ALL INPUT DATA HAS BEEN PROCESSED) 991 CLOSE(10)
IF(IUOUTEQ 8) CLOSE(8) STOP END
C SUBROUTINE GASPT(NGASTRHOXMUXKCPGRBPRIER)
C PROGRAMMED BY A M CLAUSING VERSION APRIL 1982 C PROPERTIES OF GASES IN SI UNITS(TGTO) OR ENGLISH UNITS(TLT O) C FUNCTIONAL REPRESENTATIONS USED ARE OF THE FORM Y=ATB C ARRAYS A AND B CONTAIN THE RESPECTIVE CONSTANTS C INPUT C NGAS - NGAS=l IS AIR NGAS=2 IS NITROGEN C T ---- ABSOLUTE TEMP (K) OR NEGATIVE OF ABSOLUTE TEMP (R) C OUTPUT C RHO -- DENSITY (KGM3) OR (LBMFT3)
70
C XMU -- VISCOSITY (KGM-S) OR (LBMFT-S) C XK --- THERMAL CONDUCTIVITY (WM-K) OR (BTUHR-FT-R) C CP --- SPECIFIC HEAT (JKG-K) OR (BTULBM-R) C GRB -- GBETAXNU2 (1M3-K) OR (1FT3-R) C PR --- PRANDTL NUMBER (DIMENSIONLESS) C IER -- ERROR PARAMETER C INFORMATIVE ERRORS C IER=l --- GAS NUMBER DOES NOT EXIST GAS IS ASSUMED TO BE AIR C IER=2 --- TEMPERATURE OUT OF RANGE OF PROPERTY SUBROUTINE C RESTRICTIONS C NGAS -- MUST BE l(AIR) OR 2 (NITROGEN) C T ----- T MUST LIE BETWEEN 150K AND 2100K FOR AIR AND BETWEEN C 83K AND 450K FOR NITROGEN RANGES ARE SPECIFIED WITH ARRAY R C
DIMENSION A(152)B(152)R(32) DATA A36411764E-61423E-399084178E20123 235064914E-62494E-329944985E195930 3 432491E-81239E-415534379E201137 4351618E-6221E-31031408E2084130 DATA B-1005814913800316-4639-09685 2 -999642981521962-4284023930 3 -10469389466-079-5102-0872 4 -10058058 834500239-4636-0265230 DATA R150400210083160450 IER=O IFlaquoNGASGTO) AND(NGASLT3raquo GO TO 1 IER=l NGAS=l
1 1=1 TP=T IF(TLT bullbull O) TP=-T18 IFlaquoTPLTR(lNGASraquo OR (TPGTR(3NGASraquo) IER=2 IF(TPGTR(2NGASraquoI=7 RHO=A(INGAS)TPB(INGAS) XMU=A(I+1NGAS)TPB(I+1NGAS) XK=A(I+2NGAS)TPB(I+2NGAS) CP=A(I+3NGAS)TPB(I+3NGAS) GRB=A(I+4NGAS)TPB(I+4NGAS) PR=A(I+5NGAS)TPB(I+5NGAS) IF(TGT O)RETURN RHO=RHO1602 XMU=XMUl 488 XK=XKl 731 CP=CP4187 GRB=GRB6357 RETURN END
B2 Output
Program FrigWal1 Version 8 August 1991 Programmed by AMClausing
Date Time
05-MAR-92 200227
CASE NUMBER 1 - Fresh Food Walls
Ambient Temperatures IK] Inside 2770 Outside 2940 Characteristic Lengths 1m] Inside 030 Outside 150 Surface Emissivities Inside 095 Outside 095
71
Wall Thickness 0045 m Conductivity 0027 Wm-K Area 242 m2
Q = 209 W ERRQ = 002
hconv [Wm2-K]
Inside 1 98 Outside 130
hrad [Wm2-K] 461 544
Ra
0488E+07 0459E+09
Nu
244 761
Tsur [K]
2783 2927
DeltaT [K] 13 13
RRtot
0077 0075
CASE NUMBER 2 - Fresh Food Door
Ambient Temperatures [K] Inside 2770 Outside 2940 Characteristic Lengths [m] Inside 030 Outside 150 Surface Emissivities Inside 095 Outside 095 Wall Thickness 0040 m Conductivity 0040 Wm-K Area 089 m2
Q = 117 W ERRQ = 001
hconv [Wm2-K]
Inside 218 Outside 144
hrad [Wm2-K] 463 542
Ra
0714E+07 0690E+09
Nu
269 843
Tsur [K]
2789 2921
DeltaT [K]
19 19
RRtot
0114 0113
CASE NUMBER 3 - Freezer Walls
Ambient Temperatures [K] Inside Characteristic Lengths [m] Inside Surface Emissivities Inside
2630 030 095
Wall Thickness 0056 m Conductivity 0027
Outside Outside Outside
2940 150 095
Wm-K Area 110 m2
Q = 14 3 W ERRQ = 003
hconv [Wm2-K]
Inside 226 Outside 143
hrad [Wm2-K] 397 542
Ra
0990E+07 0684E+09
Nu
292 841
Tsur [K]
2651 2921
DeltaT [K]
21 19
RRtot
0067 0061
CASE NUMBER 4 - Freezer Door
Ambient Temperatures [K] Inside 2630 Outside 2940 Characteristic Lengths [m] Inside 030 Outside 150 Surface Emissivities Inside 095 Outside 095 Wall Thickness 0040 m Conductivity 0040 Wm-K Area 034 m2
Q = 81 W ERRQ 002
hconv [Wm2-K]
Inside 259 Outside 1 64
hrad [Wm2-K] 400 538
Ra
0169E+08 0124E+10
Nu
333 967
Tsur [K]
2666 2906
DeltaT [K] 36 34
RRtot
0117 0110
72
__ ___
APPENDIX C TEST REFRIGERATOR DESCRIPTION
The test refrigerator is a White-Westinghouse model RT193MCWO 186 cubic foot
capacity top-mounted unit It is equipped with full automatic defrost The cycle time for
this unit is approximately 50 The unit also has two anti-sweat devices An electric
heater is located in the mullion region to prevent frosting between the freezer and the fresh
food compartments Also a condenser tube runs around the entire outside perimeter of the
unit embedded beneath the steel all flange Figure C1 illustrates these features
~1-- 0787 m (31)__
~ r_----------------------
1581 m
Fig CI Location of Anti-sweat Devices and Overall Dimensions of Test Refrigerator
73
Under test conditions the refrigerator and freezer are filled with milk containers full of
water These containers provide sufficient thennal mass to minimize temperature
fluctuations dming experimental runs Twenty gallons are present in the fresh food
compartment and 6 gallons are in the freezer
Figures C2 through C5 give the detailed dimensions of the fresh food compartment and
the freezer All dimensions are in millimeters and are obtained directly from the unit
Dimensions are estimated to be accurate to within plusmn 3 mm
697
762
1
305
717
Fig C2 Fresh Food Compartment Interior Dimensions
74
1127
Fig C3 Fresh Food Door
75
675
381
Fig C4 Freezer Interior Dimensions
432
Fig CS Freezer Door
76
APPENDIX D DATA ACQUISITION AND CONTROL SYSTEM
Corresponding with the construction of the experimental apparatus was the purchase and
assembly of a data acquisition and control system The system itself was designed to meet
the needs of a variety of experiments and is therefore a very flexible system
The system consists of six DC power supplies a data acquisition chassis a computer a
rack ofdigital relays and a variety of analog and digital inputs and outputs A data
acquisition and control software package orchestrates the interactions between these
components and regulates outgoing signals as well as providing data storage
External signals enter the system through a Keithley 500P data acquisition chassis These
signals consist of voltage and current measurements from the power supplies as well as
thermocouple voltages At present a total of ninety-six thermocouple inputs are available
with an optimal resolution of +0012 degrees C The addition of more thermocouple input
boards could expand the capability to 128 inputs Also special boards can be installed to
allow strain gauge thermistor digital or other standard data acquisition functions The
Keithley chassis can contain a total of nine interface boards and its l~bit AID conversion
allows for very high resolution
The six DC power supplies consist of two Hewlett Packard and four Sorensens with a
combined power of 7560 watts The Sorensens are rated at 0-150 volts at a maximum of
12 amps while the Hewlett Packards produce 0-60 volts at a maximum of 3 amps All of
the power supplies are computer-controlled however the Sorensens may be operated
manually ifdesired Voltage measurements from the power supplies are fed into the
Keithley acquisition chassis and are then routed to the computer A voltage from the
computer is buffered and fed into the control circuits of the power supplies This voltage
completes the loop and controls the output voltage of the power supplies The software is
responsible for reading the output voltage of the power supplies comparing it with the
intended setpoint and adjusting the control voltage as needed This arrangement allows the
user to vary the output voltage of the power supplies from within a program Computershy
controlled safety relays are in place to disconnect the power supplies should they stray too
far from the intended voltage setpoint Fig D1 displays the system
77
Thermocouple and Voltage Inputs
r
Computer Data Acquisition Chasis Intaface
00 Voltage and 1 r Current
Measurement
Computer
I I
Analog Control Signal
Digital Oulput Signals 5 6
Power Supply 4 Relay Rack
Power Supply 3 00000001 Power Supply 2
Buffered Analog100000001 Power Supply 1 Control Signal
1 2 3 4 5 6 - I
I00 00 )0 po po po
Ir Digital Outputs
Analog Outputs
Fig DI Data Acquisition and Control System
78
APPENDIX E EXPERIMENTAL RAW DATA AND PLOTS
E1 Temperature Profile Plots From Fixed Thermocouples
In this appendix the remaining tests for the fixed thennocouple testing presented in Section
41 are provided Figures E1 and E2 give the results from the fresh food compartment
and Figures E3 and E4 give the results from the freezer Notice the outdoor and interior
ambient temperatures are not the same as the two tests presented in Section 41
191
Run 2 ttl ~ i i
middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot
middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot-imiddotmiddot
TWall
middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotlmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot
-
Outdoor Ambient =210 degC Fresh Food Ambient =375 degC
-] _ Door ProfUe i -il- 0 Wall Profile
i 19
$-- - Tdo = 19078 - 001326x
l~l ~~i 189 i i a m
0 i -m-
i 188 middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot
187 ~ middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot 5 = 18989 - O02024x 1
F 186
~bullbullbullbullbullbullbullmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot185 i i
184 0 5 10 15 20 25
x (mm)
Fig E1 Steel Skin Temperature Plot for Fresh Food Compartment (Run 2)
79
191
19
189
a ~
i 188
187
5F
186
185
184 0
Run 3 I --D - Door Profile
middotmiddotmiddotmiddotmiddotmiddotmiddotmiddot-middotmiddotmiddotmiddot~middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotimiddotmiddot-middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddot 0 Wall Profile
i - i - - Tdo =19053 - 001384x or
=c-=r=-~-= 1 11=
~ n - 189S 001998 --t-shy-~~-
5 10 15 20 25
x (mm)
Fig E2 Steel Skin Temperature Plot for Fresh Food Compartment
186
184
182
- ~- 18
178
~ 176
174
172 0
(Run 3)
Run 2 l --0 - Door Profile
middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot~middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotdrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotf 0 Wall Profile - 1- - middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot--m
- - T =18544 - 002398x i - i door rb
~i
i bullbullbulli _ bull imiddot
~ I TWall =18182 - 003542x tmiddotmiddotmiddotmiddot middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotlmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot
~ n~l l
5 10 15 20 25
x (mm)
Fig E3 Steel Skin Temperature Plot for Freezer (Run 2)
80
--a 0
I5F
186
184
182
18
178
176
174
172
Run 3 I --0 - Door Profile
middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotCmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotl 0 ~a1l Profile
ttl __ OJ 1 1 middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotfmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotlmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot -shy - Td = 18411 - 002272x ibullbullbullbullbullbullbull-bullbullbullbullbullbullbullbullbulli
oor ~
rp bullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbullbull bull 11_1
I I middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotimiddotmiddotmiddotmiddot middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotImiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot
~ _l
Outdoor Ambient =208 degc Freezer Ambient = -93 degc
0 5 10 15 20 25
x (mm)
Fig E4 Steel Skin Temperature Plot for Freezer (Run 3)
E2 Thermopile Data Reduction
The data from the thennopile tests consist of an output voltage (mV) measured with a
Keithley multimeter which has a resolution of 1 m V The procedure required to translate
this voltage into a temperature difference follows
1 Read the output voltage in millivolts
2 Detennine the average skin temperature from fixed thennocouple data
3 Use the reference table and the average skin temperature to determine the conversion factor in Vrc
4 Convert to temperature difference as follows
1T = ____o_utpu_t_vo_l_tag-e___
ofjunctions x conversion factor
81
Table EI Thermopile Raw Data
ffOutput fzOutput ff Ave Skin Temp fz Ave Skin Temp mV mV CC CC
Roo wall door wall door wall door wall door
1 0052 0048 0045 0050 189 191 177 183
2 0054 0052 0046 0048 187 189 176 182
3 0056 0053 0046 0051 186 188 175 181 ff Conv Factor fz Conv Factor ff AT fzAT
Ilvrc Ilvre CC CC
Roo wall door wall door wall door wall door
1 40165 40181 40067 40116 026 024 037 041
2 40148 40165 40058 40107 027 026 038 040
3 40140 40157 40050 40099 027 026 038 040
Average Temperature Difference 0267 0377 0253 0403
from Thermocouple Reference Tables Based on the IPTS-68 US Dept of Commerce
E3 Experimental Determination of qwall and qdoor Details
The four heat fluxes are calculated using
-k M (El)q - m Ax
For 05 carbon cold rolled steel km =540 Wm K (312 Btuhr-ft-OF) Also Ax = OOlm (039 in) for all computations
0267degC 2 qwallff = 54 Wm-K 001 m = 14418 Wm
_ 0377 degc _ 2 qwallfz - 54 Wm-K 001 m - 20358 Wm
0~3~ 2 qdoorff =54 Wm-K 001 m =13662 Wm
82
0403degC 2 qdoorfz = 54 Wm-K 001 m = 21762 Wm
Compute the heat transfer rate according to Equation (B2)
q =qA=qhP (B2)
Where A is the cross sectional area of the steel casing that is perpendicular to the direction
of heat flow The area is the product of the steel skin thickness b and the total perimeter of
the compartment opening which is exposed to the room environment P Perimeter
definitions
Pwallff = llm + 076m +llm = 296 m
roJ D Pwallfz =O4lm + 076m + O4lm =l58 m
I ] I ~I Pdoorf( = llm + 076m + llm + 076m = 372 m
Pdoorfz =076m + O4lm + 076m + 041m =234 m
83
qwallff =(14418 Wm2)(65e-4 m)(296 m) =277 W
qwallfz =(20358 Wm2)(65e-4 m)(158 m) =209 W
qdoorff =(13662 Wm2)(65e-4 m)(372 m) =330 W
qdoorfz =(21762 Wm2)(65e-4 m)(234 m) =331 W
E4 Temperature Profile Plots From Mullion Data (Heater oro
The following plots are from the remaining runs for the mullion analysis presented in
Section 45 All data is taken from the exact center of the mullion
131
13 middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot-tmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotjmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotlmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot9middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotlmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot6middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddot T 11 f =12383 + 0019929x iii mu z
129 ~ middotImiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot[middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddota ~
i 128 middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot4middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot-j-middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotfmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotfmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot
127e ~
126 ~~~=H~~-~=HmiddotrI~ ++~11 Room Ambient =2250 degC125
1 1 i Fresh Ambient =515 degC iii i i Freezer Ambient =-603 degC
124
1 10
Fig ES Mullion Temperature Profile Run 2 (Heater Off)
Run 2
2 3 4 5 6 7 8 9
TIC
84
146
145
a 144 ~
i 143
5 ~ 142
141
Run 3 9 0
---r-r--deg-r-ideg-t-9--rshyiii ltD T 11 ff = 15173 - OOI71x mu bull
middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotfmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotImiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot6middotmiddot
1Tmull~fz =14062 + J0158211x JLt 1
Q 1 1 1 middotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1-middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddoti-middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotimiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotoot-middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot-I-bullbullbull~bullbullbullbullbullbullbullbullbullbullbull
iii middotiiimiddot-j Room
1Am~t = 21~1 degC
iii i 1 Fresh Ambient = 563 degC 1 1 1 1 1 Freezer Ambient = -153 degC
14~---+--~----r---+---~---+--~----r---+-
1 2 3 4 5 6 7 8 9
TIC I
Fig E6 Mullion Temperature Profile Run 3 (Heater Off)
127
126
125 a ~
i 124
123 e ~
122
121
12
1
Fig E7
i i CD middotmiddotmiddotmiddot----middotmiddot-r--middot---middotmiddotmiddotmiddotmiddotmiddot-lmiddot--------middotmiddotmiddotmiddotl-middotmiddot---middotmiddotmiddotmiddot---r---middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1middotmiddotmiddotmiddotmiddot---middotmiddot---middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot-r----middot1__ _-
I I I T mulIff = 1321 - 001532x middotmiddotmiddotmiddot------middott--------------tmiddotmiddot----middot----middotmiddot-1------middotmiddotmiddotmiddotmiddotmiddot---jmiddot-----middotmiddotmiddotmiddotmiddotmiddotmiddotmiddot-lmiddotmiddotmiddot---middotmiddotmiddot-----tmiddotmiddotmiddotmiddotmiddot--middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddot-----middotmiddotmiddot6middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot
I cent I I I I -~~~~-ro-Tr-
r-middotmiddotmiddotmiddotrTTr-middotrmiddotrmiddotrmiddot middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddott middotmiddotmiddottmiddotmiddot1middotmiddotbullbullbullbull fmiddotbullbullbullbullbullbullbullmiddot-fbullbullbullbullbullbullbullmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot
II Room Ambil =21~3 degC iii i i Fresh Ambient =551 degc iii i i Freezer Ambient = -681 degC
2 3 4 5 6 7 8 9 10
TIC I
Mullion Temperature Profile Run 4 (Heater Off)
85
10
111
iii i i 11
Fttul5
T mu
=J=~[rr~tl=rI=109
a ~ 108 -t-t-t-i~FFl~i~~
+-0amp_- -+_bullbullbullbullbullbullbullbull+ - bullbullbull 107 11 f ~ 10325 + 0021893x 1 1 1 ji
5 bull Z iii
------~-~-----~---i --L--l ---_l__ ---L-----_shy106 ~
105 -t---i--+-+-+-middot++-I-shyL1LLL Room Ambient = 2177 C104 iii i i Fresh Ambient =448 degC
Freezer Ambient = -644 degC 103
1 2 3 4 5 6 7 8 9 10
TIC
Fig E8 Mullion Temperature Profile Run 5 (Heater Off)
86
34
33 1 1 1 1 1 1 1 1------I---------middotmiddot--+middotmiddotmiddotmiddot------middottmiddot-------middotmiddotmiddotmiddottmiddot----------middotmiddotmiddot---middot---middot----tmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot---middotmiddott--middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot(middotmiddotmiddotmiddotmiddot--
32 11 f =1 2859 ~ OI~X j
Till ff =133013 j - 007124x mu
31
a ~ 30
i 5 ~
29
28
27
26
Tmullfz = 26944 + 014842x
mu t-tr l
25 middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotjmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotjmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotlmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1middot ~ u~ ~it
24 lllti1 ~ i i ~ i
0 Lower Limit
23
0 1 2 3 4 5 6 7 8 9 10
ES Temperature Profile Plots From Mullion Data (Heater On)
The following are the remaining plots from the mullion heater analysis presented in Section
46
TIC I
Fig E9 Mullion Temperature Profile Run 2 (CenterHeater On)
Run 2
T muz
1
87
l----+
29
middotmiddotmiddotgtmiddotmiddoti middot 0 upper Limit 28 Run 1
I
middotmiddotI o
Tmullfz
T muo
LL~4cb 0 Lower Limit27
middot~+ImiddotmiddotmiddotImiddotmiddotmiddottr9middotdJmiddotmiddotmiddotmiddot 26
t T = 29465 008022xmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddot1middotmiddotmiddotmiddotTmiddotmiddotmiddotmiddot[middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1middot mullffa 25~
i 24 =24837+ 013186x middotlmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot+middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotimiddotmiddotmiddotmiddotmiddotmiddotmiddotlmiddotmiddotmiddotmiddotmiddotmiddot iii i i
i _ Jbullbullbullbullbullbullbullbullbullbullbullbullbulli l _l ii 23
e 22~ 21 +I~=tt=l=fit
L~LLL Tm~llff = 23856 005858x20 11 f = 1803 + 02243x z -rmiddotmiddotmiddotmiddot1middot middotmiddot middotmiddot 1middotmiddotmiddotmiddotmiddotTmiddotmiddot middot-rmiddot19
18
0 1 2 3 4 5 6 7 8 9 10
TIC
35
34
33
32
a ~ 31
I ~
30
29
28
27
26
25
24
Fig EI0
---bull---i----bullbullmiddotmiddotmiddotmiddot--~--------middotmiddot-+------ j bullbullbullbull ---bullbullbullbull -i--__---
T 11 f =30063 + OI~x 1 T i 134 196 i
0068 1 38
muz tmiddotmiddot Ilff=middot bull x ltP lt1gt mu
=t=H=t+t=R=t= F-6~I-i~E
Tmullfz = 28103 + 014486x 1middot++middot1middot1
middotmiddotmiddot--middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotimiddotmiddotmiddotmiddotmiddotmiddotmiddot-middotmiddotmiddotmiddotmiddot+middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotbullbullmiddotmiddotmiddot-middotmiddotimiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot~middotmiddot
111111 0 Upper Limit iii iii 0 Lower Limit
0 1 2 3 4 5 6 7 8 9 10
TIC
Mullion Temperature Profile Run 3 (CenterHeater On)
Fig Ell Mullion Temperature Profile Run 1 (LeftHeater On)
88
a
29
28
27
26
25~
i 24
23 e
22~ 21
20
19
18
Fig E12
i l middot middotmiddotmiddotmiddotlmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot+ 0 Upper Limit T 11 f =24474 + 011288x i imu bull z o Lower Limit
=tplusmntplusmnfrplusmnplusmnplusmn ~ I I I I Tmull ff ~ 28793 - o0784x
middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddott----middot------middotmiddotimiddot----middot-middotmiddot--middot-~-middotmiddotmiddot--middot----middotmiddot)middot
=ii=t=1=P-Ltplusmnt iii i T = 25599 - 00689xIfmiddotTTTmiddotmiddotrmiddot ~Ullff iii
T l1f =20552 + 01676x i~~imiddotimiddotmiddot
==~LL L LLLLL i i 1 ~ 1 ~
0 1 2 3 4 5 6 7 8 9 10
TIC I
Mullion Temperature Profile Run 2 (LeftlHeater On)
33 iii i i
-middot--middot(---middotmiddot--middotmiddot--middotmiddot+---middot-middotmiddotmiddotmiddot-middotmiddotmiddot~-middot--middot-------middoti---middot------~ o Upper Limit 32 Run 3
t bullbullbull +
Tm~llfz
T mu
1 1 1 1 1 o Lower Limit ~~31
=2713 ~ 0113~x j11Li30
a T ulff =30658 - 006506x 29~
IktlJ2~Li 28
27 e
26 =l=tt=tmiddotmiddottmiddott+~middot+=t=~ middotmiddot jmiddotjmiddottmiddottmiddotjmiddot T = 28288 - 00603x
iii i mullff 24
25
middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotQmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot+middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot~middotmiddotmiddot middotmiddotmiddotmiddotmiddotmiddotmiddotmiddot~middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddottmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot+middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot 11 fz = 2377 ~ 01788x IL11123 i i
22
0 1 2 3 4 5 6 7 8 9 10
TIC I
Fig E13 Mullion Temperature Profile Run 3 (LeftHeater On)
89
31
30
29
ltP ~u
J
1 T
-~Lti=t~-t--t i~+--Ij Tmu1lff =31473 middot005222x 28
1 1 1middot 1 l i l i bullbullbullbullbullbullbull__ bullbullbullbull_ bullbullbullbullbullbullbull~_bullbullbullbullbullbullbullbullbulla bullbullbullbullbullbullbullbullbullbullbull a 27
~ Tm~llfz = 26857 + 01734x _~__+_+II i
26
bullmiddotmiddotbullbullbullmiddotmiddotbullibullbullbullbullbullbullbullbullbullbullbullmiddotmiddotmiddotbullbullbullbullbullbullbullbullmiddotmiddotmiddotmiddot bullbullbullbullbullbullbullbullbull-i-~-i-ii25
JJ$~L-f$9 5 24
~ 23 middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotlmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot+middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot~middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot+middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot1-middotmiddot T mllff =25622 bull 002~7X c-bullbullbullbullbullbullbullbullbullbullbullbull+ ~~ 22 rp 1 1 i i 1 1 1
21 = 19464 + 02548 jmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddott Upper Limitmullfz xii 0
4-bullbullbullbullbullbullbullbullbullbullbullbullimiddotmiddotmiddotbullbullbullbullbullbullmiddotf20 i 1 ~ 1
19
0 1 2 3 4 5 6 7 8 9 10
TIC I
Fig E14 Mullion Temperature Profile Run I (RightHeater On)
33 i
middotmiddotmiddotmiddotlaquomiddotmiddotmiddotmiddot------------------------------- c--------middotmiddotmiddot-middot-----------middotmiddotmiddot---middotmiddot--------l-----middot-----I-----32
= 2757 + 017006x ILLJ1
a
31
30
29~
i 28
Run2
TmulIfz
T~ulIfz ~
-~t=ii~Ii~~~~ i
27 middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot9-middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotrmiddotmiddotmiddotmiddotmiddotmiddotT~~middotmiddotmiddotmiddotmiddot2s944-middot~middotmiddotO0278~middotmiddote 26~ r~rrTt+rr25
24 2320~ + O~S4x middotmiddotlmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotjmiddot ~ u~ L~t 23 middotmiddotmiddotmiddotmiddotmiddotmiddotmiddot~middotmiddotmiddotmiddotmiddotmiddotmiddot+middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot+middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddot+middotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotmiddotImiddotmiddotj 0 Lower Limit
22
0 1 2 3 4 5 6 7 8 9 10
TIC I
Fig EIS Mullion Temperature Profile Run 2 (RightlHeater On)
90
33 i i ~ _______ _ _~____ __ __-i--bullbullbullbullbullbullbullbull-t------ -- uu__~ ~ --~32
=1268931+ 0~4~14X 111131
30
a 29~
I 28
Run3
Tmullfz
i t+ I T
m
mnplusmn~~27 6 i 1 i 1 +++ T mullff =28912 - 002938x 26~ +middotmiddot++Imiddotjmiddott-25
= 22996 + 02312x 1middotmiddot+ 24
~~~~L lL1 0 ~23 ill 0 22
0 1 2 3 4 5 6 7 8 9 10
TIC
Fig E16 Mullion Temperature Profile Run 3 (RightHeater On)
91
APPENDIX F NUMERICAL SIMULATION EQUATIONS AND CODE
F1 Finite-Difference Equations
Figure Fl is a generic resistor network that is used as a base for all the finite-difference
equations The general fonn is
(Fl)
r----II ij+l
J
i j-l L ______--J
Fig F1 Generic Nodal Resistor Network
This makes it easy to simply plug in the different resistors for the different regions of the
section There are twelve resistors total The following table summarizes the resistors
needed to complete the model
Table F1 Model Resistors
Description Resistance [CIW]
Interior insulation x direction Rl= dx dymiddotkinsmiddotb
92
dyInterior insulation y direction R2= dx-kins-b
dySteel parallel with insulation y direction R3= km-dm-b + kins-(dx -dm)
dxR=Steel parallel with insulation x direction km-dm-b + kins-(dy -dm)
dyRs=Plastic parallel with insulation y direction
kp-dp-b + kins-(dx -dp)
dxPlastic parallel with insulation x direction R6= kp-dp-b + kins-(dy -dp)
heffa- (~- dm) + kinsSteel to exterior x direction R7= 2
heffo-kins-dy-b
heffa- (dY - dm) + kinsSteel to exterior y direction R - 28shyheffo-kins-dx-b
hefti- (dY _dm) + kinsSteel to interior y direction R9= 2
heffi-kins-dx-b
hefti- (~- dp) + kinsPlastic to interior x direction RIO= 2
heffi-kins-dy-b
Rll = hefti- (dJ -dP) + kinsPlastic to interior y direction
heffi-kins-dx-b
93
Steel skinplastic skin interface
2middotkmmiddotdmmiddotkpmiddotdpmiddotdxR12=----------------------~~----------------
2middotkmmiddotdmmiddotkpmiddotdpmiddotbmiddot(dy -dp) + (kpmiddotdp + kmmiddotdm)middotbmiddotdx2
F2 Wall Simulation Source Code
Program FiniteDiff
c This program simulates the conductive heat transfer through the wall section c of the refrigerator near the door gasket using Guass-Siedel iteration c The program allows for flexibility in the geometry and material properties c The program is a steady-state model
cVariable Definitions
c km = conductivity of the outer metal skin (Wm-K) c kins = conductivity of the polyurethane foam insulation (Wm-K) c kp conductivity of the inner plastic skin (Wm-K) c dm = thickness of the metal skin (mm) c dp = thickness of the plastic skin (mm) c b = depth of the section (m) c heffo = effective heat transfer coefficient on outside surfaces (Wm2-K) c heffi = effective heat transfer coefficient on inside surfaces (Wm2-K) c sl width of wall inSUlation (mm) c s2 length of wall section (mm) c s3 seal indentation (mm) c s4 seal width (mm) c s5 distance metal skin travels into cabinet (mm) c s6 distance platic skin travels out of cabinet (mm) c ns = number of nodes corresponding to the s regions above c rs = network resistors (m-eW) c i = integer values of distance along the x axis c j = integer values of distance along the y axis c imax maximum integer value in x direction c jmax maximum integer value in y direction c iter total number of iterations to converge c loop convergence flag c Qinl Heat flux per unit length across the outer boundary (Wm) c Qin2 Heat flux per unit length across the inner boundary (Wm) c Qdif Qinl - Qin2 (Wm) c Qpdif = percent difference between the heat fluxes Qinl and Qin2 c Ti Inside ambient temperature (e) c To = Outside ambient temperature (e)
cDeclare Variables
INTEGER nln2n3n4n5n6ijloopimaxjmaxiter INTEGER clflaglflag2 REAL kmkinskpdmdpdxdyheffoheffi REAL TiToQdifQpdifQinlQin2 REAL sls2s3s4s5s6lenoutlenin REAL rlr2r3r4r5r6r7r8r9rlOrllr12 REAL T(-1lOl-1lOl)bqlDsumlsum2 REAL Qm(lOl)qfluxm(lOl)fluxo(OlOl)fluxi(OlOl)
94
REAL fluxcen(0101)pfluxcen(0101)pfluxo(0101) REAL pfluxi(0101)pmaxdifoneDtolaq2Dqedge1
OPEN (10file-2Dcode(v11)out1position-rewind) OPEN (11file-2Dcode(v11)out2position=rewind)
cTest Parameters
c thermal conductivity of the outer metal skin (Wm K) km-540
c thermal conductivity of the wall insulation (Wm K) kins=0021
c thermal conductivity of the inner plastic skin (Wm K) kp=015
c thickness of the metal skin (mm) dm=065
c thickness of the plastic skin (mm) dp=25
c effective heat transfer coefficient on outside surfaces (Wm2-K) heffo=681
c effective heat transfer coefficient on inside surfaces (Wm2-K) heffi=610
c width of section (mm) sl=450
c length of section (mm) s2=2000
c depth of the section (m) b=10
c inside ambient temperature (C) Ti=95
c outside ambient temperature (C) To=210
c unit conversions dm=dm1000 dp=dp1000 sl=sl1000 s2=s21000
c specify 1-dimensional tolerance (t) oneDtol=30
cMesh Parameters
c specify the following nodal mesh parameters n1=20 n2=80 n3=1 n4=9 n5=10
c various mesh dimensions dx=sln1 dy=s2n2 s3=n3dx s4=n4dx s5=n5dx s6=sl-s5-dx n6=s6dx imax=n1-1 jmax=n2-1
cInitialize temperature matrix
DO 10 j=-1jmax+1 DO 20 i=-1imax+1 T(ij)=Ti
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20 CONTINUE 10 CONTINUE
DO 30 j=Ojmax T(-Ij)=To
30 CONTINUE
DO 40 i=0n3 T(i-I)=To
40 CONTINUE
DO 50 j=Ojmax T(imax+lj)=Ti
50 CONTINUE
DO 60 i=n3+n4+1imax T(i-I)=Ti
60 CONTINUE
cResistors [m-CW]
c interior insulation x direction rl=dx(kinsdy)
c interior insulation y direction r2=dy(kinsdx)
c metalinsulation y direction r3=dy(kmdm+kins(dx-dm))
c metalinsulation x direction r4=dx(kmdm+kins(dy-dm))
c plasticinsulation y direction r5=dy(kpdp+kins(dx-dp))
c plasticinsulation x direction r6s dx(kpdp+kins(dy-dp))
c metal to exterior x direction r7=(heffolaquodx2)-dm)+kins)(heffokinsdy)
c metal to exterior y direction rB=(heffo laquody2)-dm) +kins)(heffokinsdx)
c metal to interior y direction r9=(heffilaquody2)-dm)+kins)(heffikinsdx)
c plastic to interior x direction rl0=(heffilaquodx2)-dp)+kins)(heffikinsdy)
c plastic to interior y direction rll=(heffilaquody2)-dp)+kins)(heffikinsdx)
c metalplastic interface rI2=(2kmdmkpdpdx)(2kmdmkpdp(dy-dp) + (kpdp+km dm)dxdx)
cxxxxxGuass-Siedel Iterationxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx loop=1 iter=1 DO WHILE (loop eq 1)
c Equations for row 0 i=O j=O CALL sseqn(Tr4r7r3rBijimaxjmax)
DO 70 i=ln3 j=O CALL sseqn(Tr4r4r2rBijimaxjmax)
70 CONTINUE
DO 75 i=n3+1n5-1
96
j=O IF (i le n3+n4) THEN
CALL sseqn(Tr4r4r21e20ijimaxjmax) ELSE
CALL sseqn(Tr4r4r2r9ijimaxjmax) ENDIF
75 CONTINUE
i=n5 j-O IF (i le n3+n4) THEN
CALL sseqn(Tr12r4r21e20ijimaxjmax) ELSE
CALL sseqn(Tr12r4r2r9ijimaxjmax) ENDIF
i=n5+1 j=O IF (i le n3+n4) THEN
CALL sseqn(Tr6r12r21e20ijimaxjmax) ELSE
CALL sseqn(Tr6r12r2rllijimaxjmax) ENDIF
DO 80 i=n5+2imax-l j=O IF (i le n3+n4) then
CALL sseqn(Tr6r6r21Oe20ijimaxjmax) ELSE
CALL sseqn(Tr6r6r2rllijimaxjmax) ENDIF
80 CONTINUE
i=imax j=O CALL sseqn(TrlOr6r5rllijimaxjmax)
c Equations for rows 1 thru jmax-l DO 90 j=ljmax-l
i=O CALL sseqn(Tr1r7r3r3ijimaxjmax)
DO 100 i=1imax-1 CALL sseqn(Tr1r1r2r2ijimaxjmax)
100 CONTINUE
i=imax CALL sseqn(Tr10r1r5r5ijimaxjmax)
90 CONTINUE
c Equations for row jmax j=jmax i=O CALL sseqn(Tr1r710e20r3ijimaxjmax)
DO 110 i=1imax-1 j=jmax CALL sseqn(Tr1r110e20r2ijimaxjmax)
110 CONTINUE
i=imax j=jmax CALL sseqn(Tr10r11Oe20r2ijimaxjmax)
97
c c c
Compute the difference in heat flux crossing the outer boundary and crossing the inner boundaryr ideally the difference should be zero
CALL balance(TToTidxdyn3n4imaxjmaxQdifQpdif c QinlQin2r7r9r8rlOrllb)
c Update loop variables iter-iter+l
c Convergence criterium IF (Qpdif le 20) then
loop-O ENDIF IF (iter eq 10000) THEN loop=O write(lO) Solution did not converge
ENDIF
END DO cxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
cHeat Transfer Calculations
c Compute 10 heat flux through wall CALL oneD (ToTiheffoheffikmkinskpdmdpslqlD)
c Compute the flux thru wall at each node on the c outside and inside walls [Wm2) Also the flux c in the x-direction across the center line of the c section
cl-int(nl2) fluxcen(0)=(1(r4dy))(T(cl0)-T(cl+l0)) fluxo(0)=(1(r7dy))(To-T(00)) fluxi(O)=(l(rlOdy))(T(imaxO)-Ti) DO 112 j=ljmax
fluxcen(j)=(l(rldy))(T(clj)-T(cl+lj)) fluxo(j)=(1(r7dy))(To-T(0j)) flumiddotxi (j) =(1 (rlOdy)) (T (imax j)-Ti)
112 CONTINUE
c Determine the percent of steady-state 10 losses DO 113 j=Ojmax
pfluxcen(j)=(fluxcen(j)qlD) 100 pfluxo(j)=(fluxo(j)qlD)lOO pfluxi(j)=(fluxi(j)qlD)lOO
113 CONTINUE
c Determine where the heat transfer becomes 10 c based on a criticle percentage
flagl=O DO 114 j=O jmax
a=abs(pfluxcen(j)-lOOO) IF (j ne jmax) THEN
IF (a le oneDtol) THEN jstar=j
ENDIF ELSE
IF (a le oneDtol) THEN jstar=j
ELSE flagl=l
ENDIF ENDIF
98
114 CONTINUE
c Determine the edge loss by subtracting the 10 heat c transfer from the heat transfer in the 20 region c across the centerline
flag2=0 IF (flagl eq 0) THEN
q2D=00 DO 115 j=O jstar
q2D-q2D+fluxcen(j) 115 CONTINUE
qedgel=q2D-qlD ELSE
flag2=1 ENDIF
c 10 heat flux along metal skin under the seal into c the cabinet [Wm2J Fluxes for all metal nodes are c computed as well as an average flux The flux from c node (n3+l0) to node (n3+20) is given as qlDm(l) c and so on Assume the temperature of the metal skin c is the temperature of the node at that location
suml=OO sum2=00 DO 119 i=n3+1n3+n4-l
Qm(i)=laquokmdmb)dx)(T(i0)-T(i+10raquo qfluxm(i)=(kmdx)(T(iO)-T(i+lOraquo suml=suml+Qm(i) sum2=sum2+qfluxm(i)
119 CONTINUE pmaxdif=laquoQm(n3+n4-l)-Qm(n3+1raquoQm(n3+lraquo100 qedge2-qfluxm(cl)
cOutput
c Output nodal temperatures to separate file DO 120 j=Ojmax
write(ll) (T(ij)i=Oimax) 120 CONTINUE
c Output flux info to a different file write(10) INPUT PARAMETERS write(lO) write (10 ) Section Dimensions (mm) write(lO) Width sl1000 write (10 ) Length s21000 write(10) Depth blOOO write(10) Steel skin thickness dmlOOO write(lO) Plastic skin thickness dplOOO write(lO) write(10) Mesh Geometry write(10) dx dxlOOO write(lO) dy dylOOO write(lO) Number nodes in x-direction n1 write(lO) Number nodes in y-direction n2 write(lO) Number of steel skin nodes write(lO) (including corner 00) n5+l write(10) Steel nodes under the seal n3+1 ton3+n4 write(10) write(lO) Steel skin conductivity (Wm K) km write(lO) Foam insulation conductivity (Wm K) kins write(lO) Plastic skin conductivity (Wm K) kp write(lO) Outside h (Wm2 K) heffo write(lO) Inside h (Wm2 K) heffi
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write(10) Outside Temp (C) To write(10) Inside Temp (C) Ti write(10) write (10 ) write(10) write(10) OUPUT PARAMETERS write (10 ) write(10) Number of iterations iter write(10) write(10) Heat Transfer for the Section write(10) OVerall Heat Transfer (W) Qin1 write(10) 10 Heat Flux Thru Wall (Wm2) q1D write (10 ) write(10) Heat Transfer Along Metal Skin Under Seal write(10) node to node qm[Wm2J Qm[WJ DO 135 i=n3+1n3+n4-1
write(10) i i+1 qfluxm(i) Qm(i) 135 CONTINUE
write (10 ) Maximum difference () abs (pmaxdif) write(10) IF (flag2 eq 1) THEN
write(10) The mesh does not extend far enough write(10) in the y-direction to reach 10 heat write(10) transfer for the specified tolerance write(10) ofoneDtol
ELSE write (10 ) Edge loss computed from qe=q2D-q1D qedge1 write (10 ) write(10) Edge loss computed directly from write(10) steel skin ~T at centerline qedge2
ENDIF write (10 ) write (10 ) write(10) Heat fluxes in thru the section write(10) along the centerline [Wm2J write (10 ) write(10) j flux 10 DO 136 j=Ojmax
write(10) j fluxcen(j) pfluxcen(j) 136 CONTINUE
PAUSE STOP END
C
SUBROUTINE sseqn (Trplusirminusirplusjrminusj i jimax jmax)
c This subroutine computes the temperature at node (ij) c given the temperatures of the surrounding nodes and c the resistances leading to these nodes
INTEGER ijimaxjmax REAL T(-1101-1101)rplusirminusirplusjrminusj REAL c1c2c3c4c5
c1=1rplusi c2=1rminusi c3=1rplusj c4=1rminusj c5=c1+c2+c3+c4
T(ij)=(1c5)(c1T(i+1j)+c2T(i-1j)+c3T(ij+1)+c4T(ij-1raquo
100
RETURN END
C
SUBROUTINE balance(TToTidxdyn3n4imaxjmaxQdifQpdif c Qin1Qin2r7r8r9r10r11b)
c This subroutine computes the steady-state heat balance c for the cross-section
INTEGER imaxjmaxijn3n4 REAL T(-1101-1101)TlToQin1Qin2dydx REAL r7r8r9r10r11b
c Compute the heat entering Qin1 [Wj Qin1=00 DO 10 jOjmax
Qin1=Qin1+(b(r7))(To-T(0j)) 10 CONTINUE
DO 20 i=0n3 Qin1=Qin1+(b(r8))(To-T(i0))
20 CONTINUE
c Compute the heat leaving Qin2 [Wj Qin2=00 DO 30 j=Ojmax
Qin2=Qin2+(b(r10))(T(imaxj)-Ti) 30 CONTINUE
DO 40 i=n3+n4+1imax IF (i le nS) then
Qin2=Qin2+(b(r9))(T(i0)-Ti) ELSE
Qin2=Qin2+(b(r11))(T(i0)-Ti) ENDIF
40 CONTINUE
c Compute the absolute difference in heat fluxes [Wj Qdif=abs(Qin2-Qin1)
c Compute the percent difference in the heat transfers [Wj Qpdif=(QdifQin1) 100
RETURN END
C
SUBROUTINE oneD (ToTiheffoheffikmkinskpdmdpslqlD)
c This subroutine compute the one-dimensional c heat flux through the section wall
INTEGER i REAL ToTiheffoheffikmkinskpdmdpsl REAL q1DReqdins
dins=sl-dm~dp
Req=(lheffo) + (dmkm) + (dinskins) +(dpkp)+(lheffi) q1D=(To-Ti)Req
RETURN END
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F3 Fresh Food Wan Simulation Output
INPUT PARAMETERS
Section Dimensions (mm) Width 4500 Length 2000 Depth 1000 Steel skin thickness 6500 Plastic skin thickness 2500
Mesh Geometry dx 2250 dy 2500 Number nodes in x-direction 20 Number nodes in y-direction 80 Number of steel skin nodes (including corner 00) 11 Steel nodes under the seal 2 to 10
Steel skin conductivity (Wm K) 5400 Foam insulation conductivity (Wm K) 21000E-02 Plastic skin conductivity (Wm K) 1500 Outside h (Wm2 K) 6810 Inside h (Wm2 K) 6100 Outside Temp (C) 2100 Inside Temp (C) 4000
OUPUT PARAMETERS
Number of iterations 5318
10 Heat Flux Thru Wall (Wm2) 9132
Heat Transfer Along Metal Skin Under Seal node to node qm[Wm2] Qm[W]
2 3 1619 1092 3 4 1612 1081 4 5 1660 1019 5 6 1645 1010 6 1 1626 1051 1 8 1601 1041 8 9 1569 1020 9 10 1521 9922
Maximum difference () 9101
Edge loss computed directly from steel skin 1T at centerline 1645
Heat fluxes in thru the section along the centerline [Wm2]
j flux 10 0 4284 4691 1 2246 2459 2 3513 3841 3 4554 4981 4 5311 5881 5 6001 6512 6 6488 1104 1 6868 1520
102
10
20
30
40
50
60
70
8 7169 7850 9 7412 8117
7612 8335 11 7778 8517 12 7918 8670 13 8037 8800 14 8139 8912 15 8227 9008 16 8303 9092 17 8369 9164 18 8428 9228 19 8479 9285
8525 9334 21 8565 9379 22 8601 9418 23 8634 9454 24 8663 9486 25 8690 9515 26 8714 9542 27 8736 9566 28 8756 9588 29 8775 9609
8793 9628 31 8809 9645 32 8824 9662 33 8838 9677 34 8851 9692 35 8863 9705 36 8875 9718 37 8886 9730 38 8896 9742 39 8906 9752
8916 9763 41 8925 9772 42 8933 9782 43 8941 9791 44 8949 9799 45 8956 9807 46 8963 9815 47 8970 9822 48 8976 9829 49 8982 9836
8988 9842 51 8994 9848 52 8999 9854 53 9004 9859 54 9009 9864 55 9013 9869 56 9017 9874 57 9021 9878 58 9025 9883 59 9029 9887
9032 9890 61 9036 9894 62 9039 9897 63 9042 9901 64 9044 9903 65 9047 9906 66 9049 9909 67 9051 9911 68 9053 9913 69 9055 9915
9057 9917 71 9058 9919
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72 9059 9920 73 9061 9921 74 9062 9922 75 9062 9923 76 9063 9924 77 9063 9924 78 9064 9925 79 9064 9925
j local Qwall [Wl
-1 3215 0 -45410E-02 1 -50708E-02 2 -40940E-02 3 -33836E-02 4 -27620E-02 5 -23180E-02 6 -1 9628E-02 7 -1 6076E-02 8 -1 4300E-02 9 -12524E-02 10 -10748E-02 11 -98601E-03 12 -89722E-03 13 -80842E-03 14 -71962E-03 15 -63081E-03 16 -63082E-03 17 -54202E-03 18 -54202E-03 19 -45322E-03 20 -45322E-03 21 -45322E-03 22 -45321E-03 23 -36442E-03 24 -36442E-03 25 -36442E-03 26 -27562E-03 27 -27561E-03 28 -27561E-03 29 -27561E-03 30 -27561E-03 31 -18682E-03 32 -18682E-03 33 -27561E-03 34 -18682E-03 35 -18682E-03 36 -18681E-03 37 -18682E-03 38 -98018E-04 39 -98018E-04 40 -98018E-04 41 -98018E-04 42 -98018E-04 43 -98018E-04 44 -98018E-04 45 -98018E-04 46 -98018E-04 47 -18682E-03 48 -98018E-04 49 -98018E-04 50 -98018E-04 51 -98018E-04 52 -98018E-04
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53 -98018E-04 54 -92160E-05 55 -98018E-04 56 -98018E-04 57 -98018E-04 58 -98018E-04 59 -98018E-04 60 -92160E-05 61 -98018E-04 62 -92160E-05 63 -98018E-04 64 -98018E-04 65 -92160E-05 66 -98018E-04 67 -98018E-04 68 -92245E-05 69 -92245E-05 70 -98018E-04 71 -98018E-04 72 -98018E-04 73 -92160E-05 74 -92160E-05 75 -92160E-05 76 -92160E-05 77 -92160E-05 78 -92160E-05 79 -92160E-05
Qwallff [Wm21 = 1442 Qwallff [WI = 2775
Fresh Food Nodal Temperatures
x(mm) v(mm) 1125 3375 5625 7875 10125 12375 14625 16875 19125 21375
125 1761 1755 1748 1741 1734 1727 172 1713 1706 17 375 1768 1753 1738 1723 1707 169 1671 165 1624 1589 625 1775 1752 173 1706 1682 1656 1626 1593 1552 15 875 1781 1751 1722 1691 1659 1625 1587 1544 1494 1434
1125 -1787 1751 1715 1678 1639 1598 1553 1504 1448 1384 1375 1792 1751 1709 1667 1622 1576 1526 1471 1412 1346 1625 1798 1752 1705 1658 1609 1557 1503 1446 1384 ll17 1875 1803 1753 1702 165 1597 1543 1485 1425 1362 1294 2125 1808 1754 17 1645 1589 1531 1471 1409 1344 1276 2375 1813 1756 1699 1641 1582 1522 146 1396 133 1262 2625 1817 1758 1698 1638 1577 1515 1451 1386 132 1251 2875 1822 176 1698 1636 1573 151 1445 1379 1311 1242 3125 1826 1762 1699 1635 1571 1506 144 1373 1304 1235 3375 183 1765 17 1635 1569 1503 1436 1368 1299 1229 3625 1834 1768 1701 1635 1568 1501 1433 1364 1295 1225 3875 1837 177 1703 1635 1568 15 1431 1362 1292 1222 4125 1841 1773 1705 1636 1568 1499 143 136 129 1219 4375 1845 1776 1707 1638 1568 1499 1429 1359 1289 1218 4625 1848 1778 1709 1639 1569 1499 1429 1358 1288 1216 4875 1851 1781 1711 164 157 15 1429 1358 1287 1216 5125 1854 1784 1713 1642 1571 15 1429 1358 1287 1215 5375 1857 1786 1715 1644 1573 1501 143 1358 1287 1215 5625 186 1789 1717 1646 1574 1502 1431 1359 1287 1215
105
5875 1863 1791 1719 1647 1576 1504 1432 136 1288 1215 6125 1866 1794 1721 1649 1577 1505 1433 136 1288 1216 6375 1868 1796 1723 1651 1579 1506 1434 1361 1289 1216 6625 1871 1798 1725 1653 158 1508 1435 1362 129 1217 6875 1873 18 1727 1655 1582 1509 1436 1363 1291 1218 7125 1876 1803 1729 1656 1583 151 1437 1364 1291 1218 7375 1878 1805 1731 1658 1585 1512 1439 1366 1292 1219 7625 188 1807 1733 166 1587 1513 144 1367 1293 122 7875 1882 1809 1735 1661 1588 1515 1441 1368 1294 1221 8125 1884 181 1737 1663 159 1516 1442 1369 1295 1222 8375 1886 1812 1738 1665 1591 1517 1444 137 1296 1223 8625 1888 1814 174 1666 1592 1519 1445 1371 1297 1224 8875 189 1816 1742 1668 1594 152 1446 1372 1298 1225 9125 1892 1817 1743 1669 1595 1521 1447 1373 1299 1225 9375 1893 1819 1745 1671 1596 1522 1448 1374 13 1226 9625 1895 182 1746 1672 1598 1524 1449 1375 1301 1227 9875 1896 1822 1748 1673 1599 1525 145 1376 1302 1228 10125 1898 1823 1749 1674 16 1526 1451 1377 1303 1229 10375 1899 1825 175 1676 1601 1527 1452 1378 1304 123 10625 1901 1826 1751 1677 1602 1528 1453 1379 1305 123 10875 1902 1827 1753 1678 1603 1529 1454 138 1305 1231 11125 1903 1828 1754 1679 1604 153 1455 1381 1306 1232 11375 1904 183 1755 168 1605 1531 1456 1381 1307 1232 11625 1906 1831 1756 1681 1606 1532 1457 1382 1308 1233 11875 1907 1832 1757 1682 1607 1532 1458 1383 1308 1234 12125 1908 1833 1758 1683 1608 1533 1458 1384 1309 1234 12375 1909 1834 1759 1684 1609 1534 1459 1384 131 1235 12625 191 1835 176 1685 161 1535 146 1385 131 1235 12875 1911 1836 1761 1686 1611 1536 1461 1386 1311 1236 13125 1912 1837 1761 1686 1611 1536 1461 1386 1311 1236 13375 1913 1837 1762 1687 1612 1537 1462 1387 1312 1237 13625 1913 1838 1763 1688 1613 1538 1462 1387 1312 1237 13875 1914 1839 1764 1688 1613 1538 1463 1388 1313 1238 14125 1915 184 1764 1689 1614 1539 1464 1388 1313 1238 14375 1916 184 1765 169 1614 1539 1464 1389 1314 1239 14625 1916 1841 1766 169 1615 154 1465 1389 1314 1239 14875 1917 1842 1766 1691 1616 154 1465 139 1315 1239 15125 1918 1842 1767 1691 1616 1541 1465 139 1315 124 15375 1918 1843 1767 1692 1616 1541 1466 1391 1315 124 15625 1919 1843 1768 1692 1617 1542 1466 1391 1316 124 15875 1919 1844 1768 1693 1617 1542 1467 1391 1316 1241 16125 192 1844 1769 1693 1618 1542 1467 1392 1316 1241 16375 192 1844 1769 1694 1618 1543 1467 1392 1317 1241 16625 192 1845 1769 1694 1618 1543 1468 1392 1317 1241 16875 1921 1845 177 1694 1619 1543 1468 1392 1317 1242 17125 1921 1846 177 1694 1619 1544 1468 1393 1317 1242 17375 1921 1846 177 1695 1619 1544 1468 1393 1317 1242 17625 1922 1846 1771 1695 1619 1544 1469 1393 1318 1242 17875 1922 1846 1771 1695 162 1544 1469 1393 1318 1242 18125 1922 1847 1771 1695 162 1544 1469 1393 1318 1243 18375 1922 1847 1771 1696 162 1545 1469 1394 1318 1243 18625 1923 1847 1771 1696 162 1545 1469 1394 1318 1243 18875 1923 1847 1771 1696 162 1545 1469 1394 1318 1243 19125 1923 1847 1772 1696 162 1545 1469 1394 1318 1243 19375 1923 1847 1772 1696 162 1545 1469 1394 1318 1243 19625 1923 1847 1772 1696 1621 1545 1469 1394 1318 1243 19875 1923 1847 1772 1696 1621 1545 1469 1394 1318 1243
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x(mm) y(mm) 23625 25875 28125 30375 32625 34875 37125 39375 41625 43875
125 1694 1662 1287 1033 8577 7336 6444 5795 5324 4995 375 1536 144 125 1068 9163 7946 6974 6189 5532 4944 625 1431 1334 1203 1066 9379 8252 7275 6423 5657 4935 875 136 127 1164 1051 9408 8374 7423 6548 573 4941
1125 131 1226 1132 1034 9353 8394 7477 6605 5766 4948 1375 1273 1193 1107 1017 9262 836 7478 6618 5779 4952 1625 1245 1168 1086 1002 9162 8302 7449 6607 5776 4951 1875 1223 1148 1069 9886 9064 8236 7408 6583 5764 4948 2125 1205 1132 1055 977 8974 8169 7362 6554 5747 4941 2375 1191 1119 1044 9671 8893 8107 7316 6522 5728 4933 2625 118 1108 1034 9588 8824 8051 7273 6492 5709 4925 2875 1172 11 1026 9518 8764 8002 7235 6464 5691 4916 3125 1164 1093 102 946 8713 796 7201 6439 5674 4908 3375 1159 1087 1015 9412 8671 7924 7172 6417 566 49 3625 1154 1083 101 9373 8636 7894 7148 6399 5647 4894 3875 1151 1079 1007 9341 8608 7869 7128 6383 5636 4888 4125 1148 1077 1004 9316 8585 7849 7111 637 5627 4883 4375 1146 1074 1002 9296 8566 7833 7097 6359 5619 4879 4625 1145 1073 1001 9281 8552 7821 7087 6351 5613 4875 4875 1144 1072 9995 927 8541 7811 7078 6344 5609 4872 5125 1143 1071 9987 9261 8533 7803 7072 6339 5605 487 5375 1143 1071 9982 9256 8528 7798 7067 6335 5602 4868 5625 1143 107 9979 9253 8524 7795 7064 6332 56 4867 5875 1143 107 9978 9251 8522 7793 7062 6331 5599 4866 6125 1143 1071 9979 9251 8522 7792 7061 633 5598 4866 6375 1144 1071 9981 9252 8523 7792 7061 633 5598 4865 6625 1144 1071 9984 9255 8524 7793 7062 633 5598 4865 6875 1145 1072 9988 9258 8526 7795 7063 6331 5598 4865 7125 1145 1072 9993 9261 8529 7797 7065 6332 5599 4866 7375 1146 1073 9998 9265 8533 78 7067 6333 56 4866 7625 1147 1074 10 927 8536 7803 7069 6335 5601 4867 7875 1148 1074 1001 9275 854 7806 7072 6337 5602 4867 8125 1148 1075 1001 928 8545 7809 7074 6339 5603 4868 8375 1149 1076 1002 9285 8549 7813 7077 6341 5605 4869 8625 115 1076 1003 929 8553 7817 708 6343 5606 4869 8875 1151 1077 1003 9295 8558 782 7083 6345 5608 487 9125 1152 1078 1004 93 8562 7824 7086 6347 5609 4871 9375 1152 1078 1004 9306 8567 7828 7089 635 5611 4872 9625 1153 1079 1005 9311 8571 7831 7092 6352 5612 4873 9875 1154 108 1006 9316 8575 7835 7094 6354 5614 4873 10125 1155 108 1006 9321 858 7838 7097 6356 5615 4874 10375 1155 1081 1007 9326 8584 7842 71 6358 5617 4875 10625 1156 1082 1007 933 8588 7845 7103 636 5618 4876 10875 1157 1082 1008 9335 8592 7848 7105 6362 5619 4876 11125 1157 1083 1008 9339 8596 7852 7108 6364 5621 4877 11375 1158 1083 1009 9344 8599 7855 711 6366 5622 4878 11625 1158 1084 1009 9348 8603 7858 7113 6368 5623 4879 11875 1159 1084 101 9352 8606 7861 7115 637 5625 4middot879 12125 116 1085 101 9356 861 7864 7117 6372 5626 488 12375 116 1085 1011 936 8613 7866 712 6373 5627 488 12625 1161 1086 1011 9363 8616 7869 7122 6375 5628 4881 12875 1161 1086 1011 9367 8619 7871 7124 6376 5629 4882 13125 1162 1087 1012 937 8622 7874 7126 6378 563 4882 13375 1162 1087 1012 9373 8625 7876 7128 6379 5631 4883 13625 1162 1087 1013 9376 8627 7878 7129 6381 5632 4883
107
13875 1163 1088 1013 9379 863 788 7131 6382 5633 4884 14125 1163 1088 1013 9382 8632 7882 7133 6383 5634 4884 14375 1164 1089 1013 9384 8634 7884 7134 6384 5634 4885 14625 1164 1089 1014 9387 8636 7886 7136 6385 5635 4885 14875 1164 1089 1014 9389 8638 7888 7137 6386 5636 4885 15125 1165 1089 1014 9392 864 7889 7138 6387 5637 4886 15375 1165 109 1015 9394 8642 7891 714 6388 5637 4886 15625 1165 109 1015 9396 8644 7892 7141 6389 5638 4886 15875 1165 109 1015 9398 8646 7894 7142 639 5638 4887 16125 1166 109 1015 9399 8647 7895 7143 6391 5639 4887 16375 1166 1091 1015 9401 8649 7896 7144 6392 5639 4887 16625 1166 1091 1016 9403 865 7897 7145 6392 564 4888 16875 1166 1091 1016 9404 8651 7898 7146 6393 564 4888 17125 1167 1091 1016 9405 8652 7899 7146 6394 5641 4888 17375 1167 1091 1016 9406 8653 79 7147 6394 5641 4888 17625 1167 1091 1016 9407 8654 7901 7148 6395 5641 4888 17875 1167 1092 1016 9408 8655 7902 7148 6395 5642 4889 18125 1167 1092 1016 9409 8656 7902 7149 6395 5642 4889 18375 1167 1092 1016 941 8656 7903 7149 6396 5642 4889 18625 1167 1092 1016 9411 8657 7903 715 6396 5642 4889 18875 1167 1092 1017 9411 8657 7904 715 6396 5643 4889 19125 1167 1092 1017 9412 8658 7904 715 6396 5643 4889 19375 1167 1092 1017 9412 8658 7904 715 6397 5643 4889 19625 1167 1092 1017 9412 8658 7904 715 6397 5643 4889 19875 1168 1092 1017 9412 8658 7904 715 6397 5643 4889
F4 Freezer Wall Simulation Output
INPUT PARAMETERS
Section Dimensions (mm) Width 5600 Length 2000 Depth 1000 Steel skin thickness 6500 Plastic skin thickness 2500
Mesh Geometry dx 2800 dy 2500 Number nodes in x-direction 20 Number nodes in y-direction 80 Number of steel skin nodes (including corner 00) 9 Steel nodes under the seal 2 to 8
Steel skin conductivity (Wm K) 5400 Foam insulation conductivity (Wm K) 27000E-02 Plastic skin conductivity (Wm K) 1500 Outside h (Wm2 K) 6870 Inside h (Wm2 K) 6410 Outside Temp (C) 2100 Inside Temp (C) -1000
OUPUT PARAMETERS
108
Number of iterations 5409
Heat Transfer for the Section OVerall Heat Transfer (WI 4518 10 Heat Flux Thru Wall (Wm21 1362
Heat Transfer Along Metal Skin Under Seal node to node
2 3 3 4 4 5 5 6 6 7 7 8
Maximum difference
qm[Wm2) Om(W) 3026 1967 3008 1955 2981 1938 2944 1914 2892 1880 2820 1833
(1 6799
Edge loss computed from qe=q20-q1D 1760
Edge loss compusteel skin AT
ted directly from at centerline 2981
Heat fluxes in thru the section along the centerline [Wm2)
j flux UO 0 7762 5698 1 3711 2724 2 5678 41 68 3 7275 5341 4 8508 6246 5 9437 6927 6 1013 7438 7 1066 7823 8 1106 8117 9 1137 8347 10 1162 8529 11 1182 8678 12 1199 8801 13 1213 8904 14 1225 8992 15 1235 9068 16 1244 9135 17 1252 9193 18 1259 9245 19 1266 9291 20 1271 9333 21 1276 9370 22 1281 9405 23 1285 9436 24 1289 9464 25 1293 9491 26 1296 9515 27 1299 9538 28 1302 9559 29 1305 9578 30 1307 9596 31 1310 9614 32 1312 9630 33 1314 9645 34 1316 9659 35 1318 9673 36 1319 9685 37 1321 9697
109
38 1323 9709 39 1324 9720 40 1325 9730 41 1327 9740 42 1328 9749 43 1329 9758 44 1330 9767 45 1332 9775 46 1333 9783 47 1334 97bull 90 48 1335 9797 49 1336 9804 50 1336 9810 51 1337 9816 52 1338 9822 53 1339 9828 54 1340 9833 55 1340 9838 56 1341 9843 57 1341 9847 58 1342 9852 59 1343 9856 60 1343 9859 61 1344 9863 62 1344 9866 63 1344 9870 64 1345 9873 65 1345 9875 66 1346 9878 67 1346 9880 68 1346 9882 69 1347 9884 70 1347 9886 71 1347 9888
72 1347 9889 73 1347 9891 74 1347 9892 75 1348 9893 76 1348 9893 77 1348 9894 78 1348 9894 79 1348 9894
j local Qwall [WI
-1 3067 0 -36774E-02 1 -40214E-02 2 -32314E-02 3 -25994E-02 4 -20859E-02 5 -16909E-02 6 -14144E-02 7 -12169E-02 8 -10589E-02 9 -90092E-03 10 -78242E-03 11 -70342E-03 12 -66392E-03 13 -58492E-03 14 -54542E-03 15 -50592E-03 16 -46642E-03 17 -42692E-03 18 -42692E-03
110
19 -38742E-03 20 -34792E-03 21 -30842E-03 22 -30842E-03 23 -30842E-03 24 -26892E-03 25 -26892E-03 26 -22942E-03 27 -22942E-03 28 -22942E-03 29 -22942E-03 30 -18992E-03 31 -1 8992E-03 32 -18992E-03 33 -18992E-03 34 -1 8992E-03 35 -1 5042E-03 36 -1 8992E-03 37 -15042E-03 38 -1 5042E-03 39 -11092E-03 40 -11092E-03 41 -11092E-03 42 -11092E-03 43 -11092E-03 44 -11092E-03 45 -11092E-03 46 -11092E-03 47 -71417E-04 48 -11092E-03 49 -71421E-04 50 -11092E-03 51 -71417E-04 52 -11092E-03 53 -71417E-04 54 -71421E-04 55 -71421E-04 56 -71417E-04 57 -31916E-04 58 -31920E-04 59 -31916E-04 60 -31916E-04 61 -71417E-04 62 -11421E-04 63 -71421E-04 64 -31920E-04 65 -31920E-04 66 -71417E-04 67 -31916E-04 68 -71417E-04 69 -31920E-04 70 -71421E-04 71 -31920E-04 72 -31920E-04 73 -71417E-04 74 -31916E-04 75 -31916E-04 76 -31916E-04 77 -31916E-04 78 -71417E-04 79 -71417E-04
Qwallfz [Wm2J = 2895 Qwallfz [WJ = 2721
111
Freezer Wan Nodal Temperatures
x(mm) y1mm 14 42 70 98 126 154 182 210 238 266
125 1507 1492 1477 1461 1445 143 1415 14 1385 1338 375 1519 1489 1458 1426 1392 1353 1307 1247 1154 972 625 1531 1486 1441 1393 1341 1282 1212 1121 9925 7989 875 1542 1484 1425 1363 1296 1221 1132 1023 8837 7014
1125 1553 1483 1412 1338 1258 117 1069 9508 809 6396 1375 1563 1483 1401 1317 1227 1129 102 8969 7563 5974 1625 1572 1483 1393 13 1202 1097 9824 8568 7184 5673 1875 1582 1485 1387 1287 1182 1072 9537 8269 6906 5452 2125 1591 1488 1384 1277 1167 1053 9321 8046 67 5288 2375 1599 1491 1382 1271 1157 1039 916 7881 6547 5164 2625 1608 1495 1381 1266 1149 1028 9041 7758 6433 5071 2875 1616 1499 1382 1264 1144 1021 8955 7668 6349 5002 3125 1623 1504 1384 1263 114 1016 8895 7604 6288 495 3375 1631 1509 1386 1263 1139 1013 8854 7559 6245 4913 3625 1638 1514 1389 1264 1138 1011 8829 753 6216 4888 3875 1645 1519 1393 1266 1139 1011 8816 7513 6198 4872 4125 1652 1524 1396 1269 114 1011 8813 7505 6188 4863 4375 1658 1529 14 1271 1142 1012 8817 7505 6185 486 4625 1664 1534 1405 1275 1144 1014 8826 751 6188 4861 4875 167 1539 1409 1278 1147 1016 884 752 6195 4867 5125 1676 1544 1413 1281 115 1018 8858 7533 6206 4875 5375 1682 1549 1417 1285 1153 102 8877 755 6219 4886 5625 1687 1554 1421 1289 1156 1023 8899 7568 6235 4899 5875 1692 1559 1425 1292 1159 1026 8923 7588 6252 4914 6125 1698 1563 143 1296 1162 1028 8947 7609 627 493 6375 1702 1568 1434 1299 1165 1031 8972 763 6289 4946 6625 1707 1572 1438 1303 1169 1034 8997 7653 6308 4964 6875 1712 1576 1441 1306 1172 1037 9022 7675 6329 4982 7125 1716 158 1445 131 1175 104 9048 7698 6349 5 7375 172 1584 1449 1313 1178 1043 9073 7721 6369 5018 7625 1724 1588 1452 1317 1181 1045 9098 7744 639 5036 7875 1728 1592 1456 132 1184 1048 9123 7766 641 5054 8125 1732 1595 1459 1323 1187 1051 9147 7788 643 5072 8375 1736 1599 1462 1326 1189 1053 917 781 645 509 8625 1739 1602 1465 1329 1192 1056 9194 7831 6469 5108 8875 1743 1605 1468 1332 1195 1058 9216 7852 6488 5125 9125 1746 1609 1471 1334 1197 1061 9238 7872 6507 5142 9375 1749 1612 1474 1337 12 1063 926 7892 6525 5158 9625 1752 1615 1477 134 1202 1065 9281 7911 6542 5174 9875 1755 1617 148 1342 1205 1067 9301 793 656 519 10125 1758 162 1482 1344 1207 1069 9321 7948 6576 5205 10375 1761 1623 1485 1347 1209 1071 934 7966 6593 522 10625 1763 1625 1487 1349 1211 1073 9358 7983 6608 5234 10875 1766 1627 1489 1351 1213 1075 9376 7999 6623 5248 11125 1768 163 1491 1353 1215 1077 9393 8015 6638 5262 11375 1771 1632 1494 1355 1217 1079 941 8031 6652 5275 11625 1773 1634 1496 1357 1219 1081 9426 8045 6666 5287 11875 1775 1636 1498 1359 1221 1082 9441 806 6679 53 12125 1777 1638 1499 1361 1222 1084 9456 8073 6692 5311 12375 1779 164 1501 1362 1224 1085 947 8087 6704 5322 12625 1781 1642 1503 1364 1225 1087 9483 8099 6716 5333 12875 1783 1644 1505 1366 1227 1088 9496 8111 6727 5344
112
13125 1784 1645 1506 1367 1228 109 9509 8123 6738 5353 13375 1786 1647 1508 1369 123 1091 9521 8134 6748 5363 13625 1788 1648 1509 137 1231 1092 9532 8145 6758 5372 13875 1789 165 151 1371 1232 1093 9543 8155 6768 5381 14125 1791 1651 1512 1373 1233 1094 9554 8165 6777 5389 14375 1792 1652 1513 1374 1235 1095 9564 8174 6785 5397 14625 1793 1654 1514 1375 1236 1096 9573 8183 6793 5404 14875 1794 1655 1515 1376 1237 1097 9582 8191 6801 5412 15125 1796 1656 1516 1377 1238 1098 959 8199 6808 5418 15375 1797 1657 1517 1378 1238 1099 9598 8206 6815 5425 15625 1798 1658 1518 1379 1239 11 9606 8213 6822 5431 15875 1799 1659 1519 138 124 1101 9613 822 6828 5436 16125 18 166 152 138 1241 1101 9619 8226 6834 5442 16375 18 1661 1521 1381 1242 1102 9626 8232 6839 5446 16625 1801 1661 1521 1382 1242 1103 9631 8237 6844 5451 16875 1802 1662 1522 1382 1243 1103 9637 8242 6848 5455 17125 1803 1663 1523 1383 1243 1104 9642 8247 6853 5459 17375 1803 1663 1523 1384 1244 1104 9646 8251 6857 5463 17625 1804 1664 1524 1384 1244 1105 965 8255 686 5466 17875 1804 1664 1524 1384 1245 1105 9654 8258 6863 5469 18125 1805 1665 1525 1385 1245 1105 9657 8261 6866 5471 18375 1805 1665 1525 1385 1245 1106 966 8264 6869 5474 18625 1805 1665 1525 1385 1246 1106 9662 8266 6871 5476 18875 1806 1666 1526 1386 1246 1106 9664 8268 6872 5477 19125 1806 1666 1526 1386 1246 1106 9666 827 6874 5479 19375 1806 1666 1526 1386 1246 1106 9667 8271 6875 548 19625 1806 1666 1526 1386 1246 1107 9668 8271 6876 548 19875 1806 1666 1526 1386 1246 1107 9668 8272 6876 5481
x(mm) v(mm) 294 322 350 378 406 434 462 490 518 546
125 549 054 -27 -5 -624 -727 -8 -85 -89 -92 375 548 171 -12 -338 -5 -624 -719 -795 -858 -914 625 51 22 -032 -24 -408 -543 -654 -748 -83 -907 875 474 238 0182 -175 -34 -482 -603 -71 -807 -898
1125 445 243 048 -132 -293 -436 -564 -68 -787 -89 1375 423 243 0653 -103 -259 -402 -534 -656 -772 -883 1625 406 24 0752 -084 -236 -378 -511 -638 -759 -877 1875 393 237 0808 -071 -219 -36 -495 -624 -749 -871 2125 382 233 0837 -063 -208 -348 -483 -614 -741 -867 2375 374 23 085 -058 -2 -339 -474 -606 -735 -863 2625 368 227 0855 -055 -195 -332 -467 -6 -731 -86 2875 363 225 0855 -053 -191 -328 -462 -596 -728 -858 3125 36 223 0853 -052 -189 -324 -459 -593 -725 -856 3375 357 221 0851 -051 -187 -322 -457 -59 -723 -855 3625 355 22 0849 -05 -186 -32 -455 -588 -722 -854 3875 354 219 0849 -049 -185 -319 -453 -587 -72 -853 4125 353 219 0849 -049 -184 -318 -452 -586 -72 -853 4375 353 219 0852 -049 -183 -317 -451 -585 -719 -852 4625 353 219 0855 -048 -183 -317 -451 -584 -718 middot852 4875 353 22 0861 -047 -182 -316 -45 -584 -718 -852 5125 354 22 0867 -047 -181 -315 -449 -584 -717 -851 5375 355 221 0875 -046 -181 -315 -449 -583 -717 -851 5625 356 222 0884 -045 -18 -314 -448 -582 -717 -851 5875 358 223 0894 -044 -179 -313 -448 -582 -716 -851 6125 359 225 0904 -043 -178 -313 -447 -582 -716 -851 6375 36 226 0915 -043 -177 -312 -447 -581 -716 -85
113
6625 362 227 0927 -042 -177 -311 -446 -581 -716 -85 6875 363 229 0939 -04 -176 -311 -445 -58 -715 -85 7125 365 23 0951 -039 -175 -31 -445 -58 -715 -85 7375 367 232 0964 -038 -174 -309 -444 -579 -715 -85 7625 368 233 0976 -037 -173 -308 -444 -579 -714 -85 7875 37 234 0989 -036 -172 -308 -443 -578 -714 -849 8125 371 236 1 -035 -171 -307 -442 -578 -714 -849 8375 373 237 101 -034 -17 -306 -442 -578 -713 -849 8625 375 239 103 -033 -169 -305 -441 -577 -713 -849 8875 376 24 104 -032 -168 -305 -441 -577 -713 -849 9125 378 241 105 -031 -168 -304 -44 -576 -712 -849 9375 379 243 106 -03 -167 -303 -439 -576 -712 -848 9625 381 244 107 -029 -166 -302 -439 -575 -712 -848 9875 382 245 109 -028 -165 -302 -438 -575 -712 -848 10125 384 246 11 -027 -164 -301 -438 -574 -711 -848 10375 385 248 111 -026 -163 -3 -437 -574 -711 -848 10625 386 249 112 -025 -163 -3 -437 -574 -711 -848 10875 387 25 113 -024 -162 -299 -436 -573 -711shy -848 11125 389 251 114 -023 -161 -298 -436 -573 -71 -848 11375 39 252 115 -022 -16 -298 -435 -573 -71 -847 11625 391 253 115 -022 -16 -297 -435 -572 -71 -847 11875 392 254 116 -021 -159 -297 -434 -572 -709 -847 12125 393 255 117 -02 -158 -296 -434 -572 -709 -847 12375 394 256 118 -019 -158 -296 -434 -571 -709 -847 12625 395 257 119 -019 -157 -295 -433 -571 -709 -847 12875 396 258 12 -018 -157 -295 -433 -571 -709 -847 13125 397 259 12 -017 -156 -294 -432 -57 -709 -847 13375 398 259 121 -017 -155 -294 -432 -57 -708 -847 13625 399 26 122 -016 -155 -293 -432 -57 -708 -846 13875 399 261 122 -016 -154 -293 -431 -57 -708 -846 14125 4 262 123 -015 -154 -292 -431 -569 -708 -846 14375 401 262 124 -015 -154 -292 -431 -569 -708 -846 14625 402 263 124 -014 -153 -292 -43 -569 -707 -846 14875 402 263 125 -014 -153 -291 -43 -569 -707 -846 15125 403 264 125 -013 -152 -291 -43 -569 -707 -846 15375 403 264 126 -013 -152 -291 -43 -568 -707 -846 15625 404 265 126 -012 -152 -291 -429 -568 -707 -846 15875 405 265 126 -012 -151 -29 -429 -568 -707 -846 16125 405 266 127 -012 -151 -29 -429 -568 -707 -846 16375 405 266 127 -011 -151 -29 -429 -568 -707 -846 16625 406 267 128 -011 -151 -29 -429 -568 -707 -846 16875 406 267 128 -011 -15 -289 -428 -568 -707 -845 17125 407 267 128 -01 -15 -289 -428 -567 -706 -845 17375 407 268 128 -01 -15 -289 -428 -567 -706 -845 17625 407 268 129 -01 -15 -289 -428 -567 -706 -845 17875 407 268 129 -01 -15 -289 -428 -567 -706 -845 18125 408 268 129 -01 -15 -289 -428 -567 -706 -845 18375 408 269 129 -01 -149 -289 -428 -567 -706 -845 18625 408 269 129 -001 -149 -288 -428 -567 -706 -845 18875 408 269 129 -001 -149 -288 -428 -567 -706 -845 19125 408 269 13 -001 -149 -288 -428 -567 -706 -845 19375 409 269 13 -001 -149 -288 -428 -567 -706 -845 19625 409 269 13 -001 -149 -288 -428 -567 -706 -845 19875 409 269 13 -001 -15 -288 -428 -567 -706 -845
114
FS Fresh Food Wan Simulation Output Including Anti-sweat Condenser Tube
INPUT PARAMETERS
Section Dimensions (mm) Hidth 4500 Length 2000 Depth 2960 Steel skin thickness 6500 Plastic skin thickness 2500
Mesh Geometry dx 2250 dy 2500 Number nodes in x-direction 20 Number nodes in y-direction 80 Number of steel skin nodes (including corner 00) 11 Steel nodes under the seal 2 to 10 Tube located at node 6
Steel skin conductivity (Him K) 5400 Foam insulation conductivity (Him K) 27000E-02 Plastic skin conductivity (Him K) 1500 Outside h (Hm2 K) 6870 Inside h (Hm2 K) 6700 Outside Temp (C) 2100 Inside Temp (C) 4000
OUPUT PARAMETERS
Number of iterations 602
10 Heat Flux Thru Hall (Hm2) 9132
Heat Transfer Along Metal Skin Under Seal node to node qm[Hm21 Qm[HI
2 3 -15052E+04 -2896 3 4 -15125E+04 -2910 4 5 -15198E+04 -2924 5 6 -15274E+04 -2939 6 7 3996 7688 7 8 3898 7500 8 9 3790 7292 9 10 3662 7045
Maximum difference () 1243
j qleft [HI qright [HI -1 -2957 7832 0 -92065E-02 -38838E-02 1 -77348E-02 -48044E-02 2 -51596E-02 -30284E-02 3 -32948E-02 -15188E-02 4 -1 9628E-02 -54201E-03 5 -98600E-03 16837E-03 6 -36442E-03 70ll8E-03 7 79586E-04 96757E-03 8 43478E-03 11452E-02 9 70118E-03 12340E-02 10 87877E-03 12340E-02
115
11 87879E-03 13228E-02 12 10564E-02 12340E-02 13 10564E-02 11452E-02 14 96759E-03 11452E-02 15 87877E-03 10564E-02 16 87879E-03 87877E-03 17 78999E-03 87877E-03 18 61238E-03 78999E-03 19 61240E-03 61237E-03 20 52359E-03 52358E-03 21 34598E-03 34598E-03 22 25719E-03 25717E-03 23 16838E-03 16839E-03 24 79586E-04 25 -98018E-04 26 -18681E-03 27 -27561E-03 28 -36442E-03 29 -54202E-03 30 -54202E-03 31 -7 1962E-03 32 -80842E-03 33 -8 9721E-03 34 -98602E-03 35 -10748E-02 36 -11636E-02 37 -12524E-02 38 -1 3412E-02 39 -1 4300E-02 40 -15188E-02 41 -1 5188E-02 42 -1 6076E-02 43 -16964E-02 44 -17852E-02 45 -1 7852E-02 46 -1 8740E-02 47 -19628E-02 48 -19628E-02 49 -19628E-02 50 -20516E-02 51 -21404E-02 52 -22292E-02 53 -22292E-02 54 -23180E-02 55 -23180E-02 56 -23180E-02 57 -24068E-02
79578E-04 -98018E-04 -1 8682E-03 -27561E-03 -45322E-03 -54202E-03 -71962E-03 -71962E-03 -8 9722E-03 -8 9722E-03 -10748E-02 -11636E-02 -12524E-02 -13412E-02 -14300E-02 -1 5188E-02 -16076E-02 -16964E-02 -16964E-02 -17852E-02 -18740E-02 -19628E-02 -20516E-02 -20516E-02 -21404E-02 -22292E-02 -22470E-02 -22381E-02 -22647E-02 -23358E-02 -23447E-02 -23802E-02 -24512E-02 -24690E-02
58 -23979E-02 -25223E-02 59 -24423E-02 60 -24246E-02 61 -24423E-02 62 -24779E-02 63 -25400E-02 64 -25400E-02 65 -25667E-02 66 -26199E-02 67 -26022E-02 68 -26111E-02 69 -26377E-02 70 -26022E-02 71 -26732E-02 72 -26821E-02 73 -26199E-02 74 -26643E-02
-25489E-02 -25755E-02 -25933E-02 -2 6199E-02 -26466E-02 -26643E-02 -26821E-02 -26910E-02 -27087E-02 -27265E-02 -27354E-02 -27443E-02 -27531E-02 -27620E-02 -27620E-02 -27709E-02
116
75 -26377E-02 -27709E-02 76 -26377E-02 -27709E-02 77 -26555E-02 -27709E-02 78 -26910E-02 -27620E-02 79 -26555E-02 -27620E-02
Qleft [ii] -3079 Qright [ii] 6756 Percent entering cabinet 1800
Fresh Food Nodal Temperatures (Condenser Tube)
x(mm) y(mm) 1125 3375 5625 7875 10125 12375 14625 16875 19125 21375
19875 126 1206 1154 1104 1055 1007 9608 9158 872 8294 19625 1259 1205 1153 1103 1054 1006 9602 9152 8715 8289 19375 1259 1205 1153 1102 1053 1006 9598 9149 8711 8285 19125 1259 1205 1153 1102 1053 1006 9596 9147 871 8284 18875 1259 1205 1153 1102 1053 1006 9596 9147 871 8284 18625 1259 1205 1153 1103 1054 1006 9599 915 8712 8286 18375 126 1206 1154 1103 1054 1007 9604 9154 8716 829 18125 1261 1207 1155 1104 1055 1007 9611 9161 8722 8295 17875 1263 1209 1156 1105 1056 1008 962 9169 873 8302 17625 1264 121 1158 1107 1058 101 9632 918 874 8311 17375 1266 1212 116 1109 1059 1011 9646 9193 8752 8322 17125 1269 1215 1162 1111 1061 1013 9663 9209 8766 8335 16875 1272 1217 1164 1113 1063 1015 9682 9226 8783 835 16625 1275 122 1167 1116 1066 1017 9704 9246 8801 8367 16375 1279 1224 117 1119 1069 102 9728 9269 8822 8386 16125 1282 1227 1174 1122 1072 1023 9755 9294 8845 8407 15875 1287 1231 1178 1126 1075 1026 9785 9322 887 843 15625 1292 1236 1182 113 1079 103 9818 9352 8898 8456 15375 1297 1241 1187 1134 1083 1034 9854 9385 8929 8484 15125 1302 1246 1192 1139 1088 1038 9892 9421 8962 8514 14875 1308 1252 1197 1144 1092 1042 9934 946 8998 8547 14625 1315 1258 1203 1149 1097 1047 9979 9502 9037 8583 14375 1322 1265 1209 1155 1103 1052 1003 9547 9078 8621 14125 1329 1272 1216 1162 1109 1058 1008 9595 9123 8662 13875 1337 1279 1223 1168 1115 1064 1014 9647 9171 8706 13625 1346 1287 1231 1176 1122 107 102 9703 9222 8753 13375 1355 1296 1239 1183 1129 1077 1026 9762 9277 8803 13125 1364 1305 1247 1191 1137 1084 1033 9824 9335 8856 12875 1374 1314 1256 12 1145 1092 104 9891 9396 8913 12625 1385 1325 1266 1209 1154 11 1047 9962 9462 8973 12375 1396 1335 1276 1219 1163 1109 1055 1004 9531 9037 12125 1408 1347 1287 1229 1173 1118 1064 1012 9605 9105 11875 1421 1359 1299 124 1183 1127 1073 102 9683 9176 11625 1434 1371 1311 1251 1194 1137 1082 1029 9765 9252 11375 1448 1385 1323 1263 1205 1148 1092 1038 9851 9332 11125 1462 1399 1336 1276 1217 1159 1103 1048 9943 9416 10875 1478 1413 135 1289 1229 1171 1114 1058 1004 9505 10625 1494 1429 1365 1303 1243 1184 1126 1069 1014 9598 10375 1511 1445 138 1318 1257 1197 1138 1081 1025 9696 10125 1528 1462 1397 1333 1271 121 1151 1093 1036 98 9875 1547 1479 1413 1349 1286 1225 1165 1106 1048 9908 9625 1566 1498 1431 1366 1302 124 1179 1119 106 1002
117
9375 1586 1517 145 1384 1319 1256 1194 1133 1073 1014 9125 1607 1537 1469 1402 1336 1272 1209 1147 1087 1027 8875 1629 1558 1489 1421 1355 129 1226 1163 1101 104 8625 1652 158 151 1441 1374 1308 1243 1179 1116 1054 8375 1676 1603 1532 1462 1394 1327 1261 1195 1131 1068 8125 17 1627 1555 1484 1415 1346 1279 1213 1148 1084 7875 1726 1652 1579 1507 1436 1367 1299 1231 1165 11 7625 1753 1678 1604 1531 1459 1389 1319 1251 1183 1116 7375 1781 1704 1629 1556 1483 1411 1341 1271 1202 1134 7125 1809 1732 1656 1581 1508 1435 1363 1292 1222 1152 6875 1839 1761 1684 1608 1533 146 1387 1314 1243 1172 6625 187 1791 1713 1636 156 1485 1411 1337 1264 1192 6375 1903 1823 1744 1666 1589 1512 1437 1362 1287 1214 6125 1936 1855 1775 1696 1618 1541 1464 1387 1312 1236 5875 197 1889 1808 1728 1649 157 1492 1414 1337 126 5625 2006 1923 1842 1761 1681 1601 1522 1443 1364 1285 5375 2043 196 1877 1795 1714 1633 1553 1473 1392 1312 5125 2081 1997 1914 1832 1749 1668 1586 1504 1422 134 4875 212 2036 1952 1869 1786 1704 1621 1538 1454 137 4625 2161 2076 1992 1909 1825 1741 1658 1573 1488 1403 4375 2203 2118 2034 195 1866 1782 1697 1611 1525 1437 4125 2246 2161 2077 1993 1909 1824 1738 1652 1564 1474 3875 229 2206 2123 2039 1955 1869 1783 1695 1606 1515 3625 2336 2253 217 2087 2003 1918 1831 1742 1651 1558 3375 2383 2302 222 2138 2055 197 1882 1793 1701 1606 3125 2432 2353 2273 2192 211 2026 1938 1848 1755 1658 2875 2482 2405 2328 225 217 2086 20 1909 1815 1715 2625 2533 2461 2387 2312 2234 2153 2067 1977 1881 178 2375 2586 2518 2449 2378 2304 2226 2142 2052 1955 1851 2125 264 2579 2516 2451 2381 2306 2225 2136 2039 1933 1875 2696 2642 2587 2529 2466 2396 2319 2232 2134 2026 1625 2753 2709 2664 2614 256 2497 2425 2341 2244 2133 1375 2811 278 2746 2708 2664 2611 2546 2468 2373 226 1125 2871 2854 2835 2811 278 2739 2685 2615 2524 2411 875 2932 2932 293 2923 2909 2885 2846 2787 2706 2595 625 2995 3014 3031 3045 3052 3049 3031 2989 2922 2824 375 3058 3098 3138 3175 3208 3234 3245 3223 3179 3109 125 3124 3185 3247 331 3373 3436 35 3483 3467 3451
x(mm) y(mm) 23625 25875 28125 30375 32625 34875 37125 39375 41625 43875
19875 7877 747 7071 6679 6294 5915 554 5168 4799 4432 19625 7872 7466 7067 6676 6291 5912 5538 5166 4798 4431 19375 7869 7463 7065 6674 6289 591 5536 5165 4797 443 19125 7868 7462 7063 6673 6288 591 5535 5165 4797 443 18875 7868 7462 7063 6673 6288 591 5535 5165 4796 443 18625 787 7463 7065 6674 6289 591 5536 5165 4797 443 18375 7873 7466 7067 6676 6291 5912 5537 5166 4797 443 18125 7878 747 7071 6679 6294 5914 5539 5167 4798 4431 17875 7884 7476 7076 6684 6298 5917 5542 5169 4799 4431 17625 7893 7483 7083 6689 6303 5921 5545 5172 4801 4432 17375 7903 7492 7091 6696 6309 5926 5549 5175 4803 4433 17125 7914 7503 71 6704 6316 5932 5553 5178 4806 4435 16875 7928 7515 7111 6714 6324 5939 5559 5182 4809 4436 16625 7943 7529 7123 6725 6333 5947 5565 5187 4812 4438 16375 796 7544 7137 6737 6343 5955 5572 5192 4815 444 16125 7979 7561 7152 675 6355 5965 558 5198 4819 4442
118
15875 8001 7581 7169 6765 6368 5976 5589 5205 4824 4445 15625 8024 7601 7188 6781 6382 5987 5598 5212 4829 4447 15375 8049 7624 7208 6799 6397 6 5608 522 4834 445 15125 8077 7649 723 6819 6414 6014 562 5229 484 4453 14875 8107 7676 7254 684 6432 603 5632 5238 4847 4457 14625 8139 7705 728 6862 6451 6046 5645 5248 4854 4461 14375 8174 7737 7308 6887 6472 6064 566 5259 4861 4465 14125 8211 777 7338 6913 6495 6083 5675 5271 4869 4469 13875 8251 7806 737 6941 6519 6103 5691 5283 4878 4474 13625 8294 7845 7405 6972 6545 6125 5709 5297 4887 4479 13375 834 7886 7441 7004 6573 6148 5728 5311 4897 4484 13125 8388 793 748 7038 6603 6173 5748 5326 4907 449 12875 844 7977 7522 7075 6634 62 5769 5343 4918 4496 12625 8495 8026 7566 7114 6668 6228 5792 536 493 4502 12375 8553 8079 7613 7155 6703 6258 5816 5378 4943 4509 12125 8615 8135 7663 7199 6741 6289 5842 5398 4956 4517 11875 868 8194 7716 7245 6781 6323 5869 5418 4971 4524 11625 8749 8256 7771 7294 6823 6358 5898 544 4986 4532 11375 8822 8322 783 7346 6868 6396 5928 5463 5002 4541 11125 8899 8392 7892 7401 6915 6435 596 5488 5018 455 10875 898 8465 7958 7458 6965 6477 5994 5514 5036 456 10625 9066 8542 8027 7519 7018 6521 6029 5541 5055 457 10375 9155 8624 81 7583 7073 6568 6067 557 5075 4581 10125 925 8709 8177 7651 7131 6617 6107 56 5095 4592 9875 9349 8799 8257 7722 7193 6669 6149 5632 5117 4604 9625 9454 8894 8342 7797 7257 6723 6193 5665 514 4617 9375 9564 8994 8431 7875 7325 678 6239 5701 5165 463 9125 9679 9098 8525 7958 7397 684 6288 5738 519 4644 8875 98 9208 8624 8045 7472 6904 6339 5777 5217 4659 8625 9927 9324 8727 8137 7551 6971 6393 5819 5246 4674 8375 1006 9445 8836 8233 7635 7041 645 5862 5276 4691 8125 102 9572 895 8334 7722 7115 651 5908 5307 4708 7875 1035 9706 907 844 7814 7192 6573 5956 5341 4726 7625 105 9846 9197 8552 7911 7274 664 6007 5376 4745 7375 1066 9994 933 867 8014 7361 671 6061 5413 4766 7125 1083 1015 947 8794 8121 7452 6784 6118 5452 4787 6875 1101 1031 9617 8925 8235 7548 6862 6178 5494 481 6625 112 1049 9773 9063 8356 765 6945 6241 5537 4834 6375 114 1067 9937 9209 8483 7757 7033 6308 5584 4859 6125 1161 1086 1011 9364 8618 7872 7126 638 5634 4887 5875 1183 1106 103 9528 8761 7993 7225 6456 5686 4916 5625 1207 1128 1049 9703 8914 8123 7331 6537 5743 4947 5375 1231 1151 107 9889 9076 8261 7443 6624 5803 498 5125 1258 1175 1092 1009 925 8409 7564 6717 5867 5015 4875 1286 1201 1116 103 9436 8567 7694 6816 5936 5053 4625 1316 1229 1142 1053 9637 8738 7833 6924 601 5094 4375 1349 1259 1169 1078 9853 8922 7983 7039 609 5138 4125 1384 1292 1199 1104 1009 912 8146 7164 6177 5186 3875 1422 1327 1231 1133 1034 9336 8321 7299 627 5237 3625 1463 1365 1266 1165 1062 957 8512 7445 637 5291 3375 1508 1407 1304 1199 1092 9824 8719 7603 6479 middot535 3125 1557 1453 1346 1237 1124 101 8943 7773 6595 5412 2875 1612 1504 1393 1278 116 104 9185 7956 6719 5478 2625 1673 1561 1444 1323 1199 1073 9446 8152 6851 5546 2375 1741 1624 1501 1373 1242 1108 9725 8359 6989 5617 2125 1818 1695 1565 1429 1289 1146 1002 8575 713 5687 1875 1906 1775 1636 149 1339 1186 1032 8792 727 5755 1625 2007 1868 1716 1556 1392 1227 1062 9001 7401 5818
119
1375 1125 875 625 375 125
2127 2271 2449 2679 2994 3436
1975 2103 226
2467 2776 3361
1807 1912 2032 2173 2333 2469
1629 1707 1788 1863 191
1868
1447 1501 1548 1575 1559 1454
1266 1301 1324 1324 1279 1163
109 1111 112
1107 1058 9548
9183 9311 934
9205 8813 8043
7514 7591 7611 7544 735
6956
5873 5918 5953 5988 6049 6199
F6 Freezer Wall Simulation Output Including Anti-sweat Condenser Tube
INPUT PARAMETERS
Section Dimensions (mm) Width Length Depth Steel skin thickness Plastic skin thickness
5600 2000 1580 6500 2500
Mesh Geometry dx dy Number nodes in x-direction Number nodes in y-direction Number of steel skin nodes (including corner 00) Steel nodes under the seal Tube located at node
2800 2500 20 80
11 2 to 10 6
Steel skin conductivity (Wm K)
Foam insulation conductivity (Wm K) Plastic skin conductivity (Wm K)
Outside h (Wm2 K) Inside h (Wm2 K) Outside Temp (C) Inside Temp (C)
5400 27000E-02 1500 6870 6410 2100 -1000
OUPUT PARAMETERS
Number of iterations 879
ID Heat Flux Thru Wall (Wm2) 1362
Heat Transfer Along Metal Skin Under Seal node to node qm[Wm2] Qm[W]
2 3 -15024E+04 -1543 3 4 -15111E+04 -1552 4 5 -15205E+04 -1562 5 6 -15310E+04 -1572 6 7 5828 5986 7 8 5690 5844 8 9 5535 5684 9 10 5348 5492
Maximum difference (Is) 1356
j qleft[W] qright[W] -1 -1566 5928
120
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63
0 -62085E-02 -31363E-02 -5 9522E-02 -40097E-02 -44286E-02 -30955E-02 -33621E-02 -21814E-02 -25242E-02 -1 4577E-02 -1 8767E-02 -9 6252E-03 -13815E-02 -58162E-03 -10387E-02 -31499E-03 -73398E-03 -1 6265E-03 -54353E-03 -10285E-04
-35309E-03 27805E-04 -23882E-03 65891E-04 -16265E-03 14208E-03 -1 24 55E-03 14207E-03 -48371E-04 14207E-03 -10285E-04 10398E-03 -10285E-04 10399E-03 -10281E-04 10398E-03 -48371E-04 65891E-04 -1 02 85E-04 27805E-04 -86465E-04 16377E-04 -48375E-04 -52182E-04 -86465E-04 -97886E-04 -1 2455E-03 -13979E-03 -1 7788E-03 -16645E-03 -19692E-03 -21597E-03 -24263E-03 -25786E-03 -30357E-03 -30357E-03 -33404E-03 -35309E-03 -3 7975E-03 -3 9879E-03 -41784E-03 -44450E-03 -45974E-03 -49402E-03 -50164E-03 -53592E-03 -54353E-03 -58162E-03 -58543E-03 -62733E-03 -62733E-03 -66923E-03 -66542E-03 -71493E-03 -70351E-03 -75303E-03 -74541E-03 -7 9111E-03 -77969E-03 -83301E-03 -81397E-03 -87491E-03 -85206E-03 -90919E-03 -88634E-03 -94728E-03 -92062E-03 -97775E-03 -95109E-03 -10158E-02 -98537E-03 -10463E-02 -1 0158E-02 -10768E-02 -1 04 63E-02 -11073E-02 -10692E-02 -11377E-02 -10996E-02 -11644E-02 -11225E-02 -1 1949E-02 -11492E-02 -12215E-02 -11758E-02 -12444E-02 -11949E-02 -12672E-02 -12177E-02 -12901E-02 -12368E-02 -13129E-02 -12596E-02 -1 3282E-02 -12748E-02 -1 351 OE-02 -1 2977E-02 -13701E-02 -13129E-02 -1 3853E-02 -13282E-02 -14005E-02 -1 3434E-02 -14158E-02 -13586E-02 -14310E-02 -1 3701E-02 -14463E-02
121
64 -1 3815E-02 -1 4577E-02 65 -1 392 9E-02 -14691E-02 66 -14005E-02 -14767E-02 67 -14120E-02 -14881E-02 68 -14196E-02 -14958E-02 69 -1 4272E-02 -15034E-02 70 -14310E-02 -15110E-02 71 -1 4386E-02 -1 5148E-02 72 -14424E-02 -15186E-02 73 -14463E-02 -15224E-02 74 -14501E-02 -1 5262E-02 75 -14501E-02 -1 5300E-02 76 -14539E-02 -15262E-02 77 -14539E-02 -15300E-02 78 -1 4539E-02 -15262E-02 79 -14501E-02 -1 5300E-02
Qleft [Wj -1653 Qright [Wj 5163 Percent entering cabinet 2380
Freezer Nodal Temperatures (Condenser Tube)
x(mm) y(mm) 14 42 70 98 126 154 182 210 238 266
19875 9606 8457 7334 6235 516 4107 3075 2064 107 00944 19625 9596 8448 7325 6227 5152 4099 3068 2056 1064 00882 19375 9591 8443 732 6222 5148 4095 3064 2053 106 00850 19125 9591 8443 732 6222 5147 4095 3064 2052 106 00847 18875 9596 8448 7325 6226 5151 4099 3067 2056 1063 00873 18625 9606 8457 7334 6235 5159 4106 3074 2062 1069 00928 18375 9621 8472 7347 6248 5171 4118 3085 2072 1078 01013 18125 9641 8491 7366 6265 5188 4133 3099 2085 109 01128 17875 9666 8514 7388 6287 5208 4152 3117 2102 1106 01272 17625 9696 8543 7416 6313 5233 4176 3139 2123 1125 01447 17375 9731 8577 7448 6343 5262 4203 3165 2147 1147 01652 17125 9772 8616 7485 6378 5295 4234 3194 2174 1173 01888 16875 9817 8659 7526 6418 5333 427 3228 2206 1202 02156 16625 9868 8708 7573 6462 5375 431 3265 224 1234 02455 16375 9924 8762 7624 6511 5421 4353 3306 2279 127 02786 16125 9985 8821 7681 6565 5472 4402 3352 2322 131 03149 15875 1005 8885 7742 6624 5528 4454 3401 2368 1353 03546 15625 1012 8954 7809 6687 5588 4511 3455 2418 1399 03976 15375 102 9029 7881 6755 5653 4573 3513 2472 145 04441 15125 1029 911 7958 6829 5723 4639 3575 253 1504 0494 14875 1038 9196 804 6907 5798 4709 3641 2592 1562 05474 14625 1047 9287 8128 6991 5877 4784 3712 2659 1623 06045 14375 1057 9385 8221 708 5962 4865 3787 2729 1689 06652 14125 1068 9488 832 7175 6052 495 3868 2804 1759 07297 13875 1079 9597 8424 7275 6147 504 3952 2884 1833 07981 13625 1091 9713 8535 738 6247 5135 4042 2968 1911 08704 13375 1104 9834 8651 7491 6353 5235 4136 3056 1993 09466 13125 1117 9962 8774 7608 6464 534 4236 315 208 1027 12875 1131 101 8902 7731 6581 5451 434 3248 2172 1112 12625 1146 1024 9037 786 6704 5568 445 3351 2268 1201 12375 1161 1038 9178 7995 6833 569 4566 3459 2369 1294
122
12125 1177 1054 9326 8136 6967 5818 4686 3572 2475 1392 11875 1194 107 9481 8284 7108 5951 4813 3691 2585 1494 11625 1211 1087 9642 8439 7256 6091 4945 3815 2701 1602 11375 1229 1104 981 86 7409 6237 5083 3945 2822 1714 11125 1248 1122 9985 8768 757 639 5227 4081 2949 1832 10875 1268 1141 1017 8943 7737 6549 5378 4222 3082 1954 10625 1288 1161 1036 9125 7911 6714 5534 437 322 2083 10375 1309 1181 1055 9314 8092 6887 5698 4524 3364 2217 10125 1331 1203 1076 9511 8281 7067 5868 4685 3514 2356 9875 1354 1225 1097 9716 8477 7254 6046 4852 3671 2502 9625 1378 1248 1119 9929 8681 7448 6231 5026 3835 2654 9375 1402 1271 1142 1015 8893 7651 6423 5208 4005 2813 9125 1428 1296 1166 1038 9113 7861 6623 5398 4183 2979 8875 1454 1321 1191 1062 9342 808 6832 5595 4369 3152 8625 1481 1348 1216 1086 9579 8308 7049 5801 4562 3333 8375 1509 1375 1243 1112 9826 8545 7275 6015 4764 3522 8125 1538 1403 127 1139 1008 8791 751 6238 4975 3719 7875 1568 1432 1299 1166 1035 9047 7755 6472 5196 3925 7625 1598 1462 1328 1195 1063 9314 8011 6715 5426 4142 7375 163 1494 1358 1224 1091 9591 8278 697 5667 4368 7125 1663 1526 139 1255 1121 9881 8556 7236 5919 4606 6875 1697 1559 1422 1287 1152 1018 8847 7514 6184 4855 6625 1731 1593 1456 132 1185 105 9151 7806 6462 5118 6375 1767 1629 1491 1355 1218 1083 9469 8113 6755 5394 6125 1804 1665 1527 139 1254 1117 9804 8435 7063 5686 5875 1842 1703 1565 1428 129 1153 1015 8774 7388 5995 5625 1881 1742 1604 1466 1329 1191 1052 9133 7732 6322 5375 1921 1782 1644 1507 1369 1231 1091 9511 8097 6669 5125 1962 1824 1686 1549 1411 1272 1133 9913 8485 7039 4875 2004 1867 173 1593 1455 1317 1176 1034 8899 7435 4625 2047 1912 1776 164 1502 1363 1223 108 9341 7859 4375 2092 1958 1823 1688 1552 1413 1272 1128 9816 8315 4125 2138 2005 1873 1739 1604 1466 1325 1181 1033 8807 3875 2184 2055 1925 1793 166 1523 1382 1238 1088 934 3625 2232 2106 1979 1851 1719 1584 1444 1299 1148 992 3375 2282 216 2037 1911 1783 1649 1511 1366 1214 1055 3125 2332 2215 2097 1976 1851 1721 1584 1439 1286 1125 2875 2384 2273 2161 2045 1925 1798 1663 152 1366 1202 2625 2436 2334 2229 212 2005 1883 1751 1609 1455 1288 2375 249 2397 2301 22 2093 1976 1849 1708 1554 1384 2125 2546 2463 2377 2287 2188 2079 1957 182 1666 1493 1875 2602 2532 2459 238 2293 2193 2079 1946 1793 16 17 1625 266 2605 2546 2482 2407 232 2215 2089 1939 176 1375 2719 2681 264 2592 2533 2461 2369 2253 2108 1928 1125 2779 2761 2739 271 2671 2618 2543 244 2305 2128 875 2841 2844 2844 2838 2822 2792 2739 2655 2535 2367 625 2903 293 2954 2974 2986 2984 2959 2899 2802 2658 375 2967 3018 3069 3117 316 3194 3209 3173 3108 3009 125 3032 3108 3186 3263 3342 3421 35 347 344 3412
x (nun) y (nun) 294 322 350 378 406 434 462 490 518 546
19875 -0865 -1811 -2743 -3663 -4573 -5474 -6368 -7257 -8141 -9022 19625 -0871 -1816 -2747 -3667 -4577 -5477 -6371 -7259 -8142 -9024 19375 -0874 -1819 -275 -3669 -4578 -5479 -6372 -726 -8143 -9024 19125 -0874 -1819 -275 -367 -4579 -5479 -6372 -726 -8144 -9025 18875 -0872 -1817 -2748 -3668 -4577 -5478 -6372 -7259 -8143 -9025
123
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124
4125 7246 5647 4014 2349 06577 -1055 -2785 -4528 -6279 -8036 3875 775 6116 444 2728 0986 -0780 -2565 -4362 -6168 -7978 3625 8299 6625 4902 3137 1339 -0486 -233 -4187 -6051 -7919 3375 8899 718 5404 3579 1717 -0173 -2082 -4003 -593 -7859 3125 9558 7787 595 4057 2122 01586 -1823 -3813 -5806 -7798 2875 1028 8455 6545 4573 2555 0508 -1553 -3618 -568 -7739 2625 1109 9192 7197 513 3014 0872 -1277 -3422 -5558 -7683 2375 12 1001 7912 5729 3497 1245 -1002 -3233 -5442 -7633 2125 1301 1093 8698 6373 3998 1618 -0739 -3059 -534 -7592 1875 1418 1196 9566 7058 4508 1975 -0503 -2914 -5262 -7564 1625 1552 1314 1053 778 5007 2292 -0319 -2818 -5218 -7554 1375 171 1452 116 8525 5462 2528 -0224 -2798 -5226 -7564 1125 19 1616 1281 9263 5815 2621 -0272 -2892 -5304 -7597 875 2136 182 1417 9928 5968 2477 -0537 -3151 -5478 -7651 625 244 2095 1569 1037 575 1953 -112 -3637 -5773 -7713 375 2845 2514 1726 1027 4873 0854 -2146 -4427 -6224 -7757 125 3384 3296 1814 8879 2904 -1057 -3745 -5602 -6885 -7725
F bull 7 Seal Simulation Source Code and Ouput
Program Seal
c This program simulates the heat transfer characteristics of an c idealized refrigerator door gasket The steady-state temperature c profile is determined numerically from a 2-D finite difference c code
cxxxxxxxxxxxxx Parameters and Variablesxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
integer NNNWnsurfijjlloopiters real emmissigmakhihoTiTodelsNN real depthareatolkair
parameter (N=6) parameter (NN=20) parameter (W=7) parameter (nsurf=4N-l) parameter (emmis=09) parameter (sigma=567e-8) parameter (k=03) parameter (kair=0026) parameter (hi=641) parameter (ho=687) parameter (Ti=1032) parameter (To=209) parameter (sNN=02) parameter (del=sNNNN) parameter (depth=10) parameter (area=deldepth) parameter (tol=10)
real x(Onsurf)y(Onsurf)len(ONOnsurf) real F(OnsurfOnsurf) real T(-lNN+lONN)radl(nsurf+l)rad(Onsurf) real Eb(Onsurf)bvector(nsurf+l)Amatrix(nsurf+lnsurf+l) real difasumqsumqtotqin(NN-l) real rlr2r3r4r5
125
real clc2c3c4c5c6c7
open (lfilemiddotGasketoutposition-rewind) open (2file=Gasket(q)outpositionmiddotrewind)
cxxxxxxxxxxxxx Determine Viewfactors xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
call Points(Ndelnsurfxy) call length(Ndelnsurfxylen) call Vfactor(NdelnsurflenF)
cxxxxxxxxxxxxx Resistors (C-m2W)
c Interior x- and y-directions rl=delk
c Exterior to outdoor ambient r2=1ho
c Exterior to indoor ambient r3-1hi
c Radiation r4=(1-emmis)emmis
c Air r5=delkair
xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
cxxxxxxxxxxxxx Guass-Siedel Iteration xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
c Begin massive loop to determine the steady-state temperature c distribution across the section First update the interior nodes c by considering the radiative heat transfer among the interior c surfaces The radiative transfer is updated by calling a routine c which computes the new radiosities every iteration Loop until c tolerance is met
c Initialize temperature field do 10 i=ONN
do 11 jONN T(ij)=50
11 continue 10 continue
do 15 j=ONN T(-1j)=250 T(NN+lj)=50
15 continue
c Set temperatures for row y=O and row y=NN do 20 i=ONN
T(iO)=fl(idel) T(iNN)=f2(idel)
20 continue
cxxxxxxxxxxxxx Begin Iteration xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
loop=l iters=l do while (loop eq 1)
c Update radiosities using new temps and update interior surface nodes
call Jsolver(FemmissigmaTNNNWnsurfradlradEb + bvectorAmatrix)
c interior corners cl=area (2rl) c2=arearl
126
c3=area (2rl) c4=arearl c5=arear4 c6=1(cl+c2+c3+c4)
T(WW)=c6(clT(W+lW)+c2T(W-lW)+c3T(WW+l)+ + c4T(WW-l)+c5(rad(0)-Eb(0raquo)
cl=arearl c2=area(2rl) c3=area(2rl) c4=arearl c5=arear4 c6-1(cl+c2+c3+c4) T(W+NW)=c6(clT(W+N+lW)+c2T(W+N-lW)+c3T(W+NW+l)+
+ c4T(W+NW-l)+c5(rad(N)-Eb(Nraquo) clarearl c2-area (2rl) c3-arearl c4=area(2rl) c5=arear4 c6=1(cl+c2+c3+c4) T(W+NW+N)=c6 (clT(W+N+lW+N)+c2T(W+N-lW+N) +c3T(W+NW+N+l)+
+ c4T(W+NW+N-l)+c5(rad(2N)-Eb(2Nraquo) cl=area(2rl) c2=arearl c3=arearl c4=area(2rl) c5=arear4 c6=1(cl+c2+c3+c4) T(WW+N)=c6 (clT(W+lW+N) +c2T(W-lW+N)+c3T(WW+N+l) +
+ c4T(WW+N-l)+c5(rad(3N)-Eb(3Nraquo)
c Interior surface y=W jl=l do 22 i=W+lW+N-l
cl=area(2rl) c2=area (2rl) c4=arearl c5=arear4 c7=arear5 c6=1(cl+c2+c4+c7) T(iW)=c6(clT(i+lW)+c2T(i-lW)+
+ c7T(iW+l)+c4T(iW-l)+c5(rad(jl)-Eb(jlraquo) jl=j1+1
22 continue
c Interior surface y=N+W jl=3N-l do 25 i=W+lW+N-l
cl=area(2rl) c2=area (2rl) c3=arearl c5=arear4 c7=arear5 c6=1(cl+c2+c3+c7) T(iW+N)=c6(clT(i+lW+N)+c2T(i-lW+N)+
+ c7T(iW+N-l)+c3T(iW+N+l)+c5(rad(jl)-Eb(jlraquo) jl=jl-l
25 continue
c interior surface x=W jl=4N-l do 30 j=W+lW+N-l
c2=arearl
127
c3=area (2rl) c4=area(2rl) c5-arear4 c7-arear5 c6-1(c2+c3+c4+c7) T(Wj)-c6(c7T(W+lj)+c2T(W-lj)+c3T(Wj+l)+
+ c4T(Wj-l)+c5(rad(jl)-Eb(jl))) jl=jl-l
30 continue
c interior surface x=W+N jl=N+l do 35 j-W+lW+N-l
cl=arearl c3=area(2rl) c4=area (2rl) c5-arear4 c7-arear5 c6-1(cl+c3+c4+c7) T(W+Nj)=c6(clT(W+N+lj)+c7T(W+N-lj)+c3T(W+Nj+l)+
+ c4T(W+Nj-l)+c5(rad(jl)-Eb(jl))) jl=j1+1
35 continue
c Interior air nodes do 37 j=W+lN+W-l
do 38 i=W+lN+W-l call sseqn(Tr5r5r5r5areaareaareaareaijNN)
38 continue 37 continue
c Solid nodes do 40 i=lNN-l
do 45 jlW-l call sseqn(TrlrlrlrlareaareaareaareaijNN)
45 continue do 50 j=W+N+lNN-l
call sseqn(TrlrlrlrlareaareaareaareaijNN) 50 continue 40 continue
do 55 j=WW+N do 60 i=lW-l
call sseqn(TrlrlrlrlareaareaareaareaijNN) 60 continue
do 65 i=W+N+lNN-l call sseqn(TrlrlrlrlareaareaareaareaijNN)
65 continue 55 continue
c Side boundaries do 70 j=lNN-l
call sseqn(Trlr2rlrlareaareaarea2area20jNN) call sseqn(Tr3rlrlrlareaareaarea2area2NNjNN)
70 continue
c Apply energy balance around the boundary of the gasket to determine c stopping criterium dif
dif-OO dif=dif+(area(2rl))(T(00)-T(01)) dif=dif+(area(2rl))(T(0NN)-T(0NN-l)) do 90 i=lNN-l
dif=dif+(arearl)(T(iO)-T(il)) dif=dif+(arearl)(T(iNN)-T(iNN-l))
128
90 continue dif=dif+(area(2r1raquo(T(NN0)-T(NN1raquo dif=dif+(area(2r1raquo(T(NNNN)-T(NNNN-1raquo
do 95 j=1NN-1 dif=dif+(arear2)(To-T(0jraquo dif-dif+(arear3)(Ti-T(NNjraquo
95 continue
print dif
c Stopping criterium if (dif It toll then
loop-O endif if (iters eq 10000) then
loop=O endif
iters=iters+1 end do
cxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx c Compute heat flux into the cabinet
qsum=OO asum=OO do 97 j=1NN-1
qin(j)=hiarea(T(NNj)-Ti) qsum=qsum+qin(j) asum=asum+area
97 continue qtot=qsumasum write(2) heat flux to interior [Wm2)qtot
do 100 j=NNO-l write(l) (T(ij)i=ONN)
100 continue
pause stop end
c----------------------------------------------------------------------shyc------~----------------------------------------------------------------
Subroutine Points(Ndelnsurfxy)
integer Nnsurfi real delincrx(Onsurf)y(Onsurf)
x(O)=OO y(0)=del2
c Points along y=O edge incr-OO do 10 i=lN
y(i)=OO x(i)=(del2)+incr incr=incr+del
10 continue
c Points along x=Ndel edge incr=OO do 20 i=N+12N
x(i)=Ndel
129
y(i)-(del2)+incr incr-incr+del
20 continue
c Points along y=Ndel edge incr=OO do 30 i=3N2N+l-1
y(i)-Ndel x(i)=(del2)+incr incr-incr+del
30 continue
c Points along x-O edge incr=OO do 40 i-nsurf3n+l-1
xli) -00 y(i)-laquo3del)2)+incr incr-incr+del
40 continue
return end
c----------------------------------------------------------------------shyc-----------------------------------------------------------------------
Subroutine length(Ndelnsurfxylen)
integer Nnsurfij real dellen(ONOnsurf)x(Onsurf)y(Onsurf)
c Special case surface 0 do 10 j=Onsurf
len(0j)=sqrtlaquox(0)-x(jraquo2+(y(0)-y(jraquo2) 10 continue
c Surfaces along y=O do 20 i=IN-l
do 30 j=Onsurf len(ij)=sqrtlaquox(i)-x(jraquo2+(y(i)-y(jraquo2)
30 continue 20 continue
c Special case surface N do 50 j=Onsurf
len(Nj)=sqrtlaquox(N)-x(jraquo2+(y(N)-y(jraquo2) 50 continue
return end
c----------------------------------------------------------------------shyc-----------------------------------------------------------------------
Subroutine Vfactor(NdelnsurflenF)
integer Nnsurfijjlj2 real dellen(ONOnsurf)F(OnsurfOnsurf)Lzero
c Determine viewfactors for special case of surface 0 Lzero=delsqrt(20) do 10 j=Onsurf
if (j eq 0) then F(Oj)=OO
elseif (j eq nsurf) then F(Oj)=(len(Oj)+len(10)-len(00)-len(ljraquo(2Lzero)
else F(0j)=(len(0j)+len(lj+l)-len(Oj+l)-len(ljraquo(2Lzero)
130
endif 10 continue
c Determine viewfactors for surfaces on edge y-O
do 20 i=IN-l do 30 j=Onsurf
if (i eq j) then F(ij)=OO
elseif (j eq nsurf) then F(ij)=(len(ij)+len(i+l0)-len(i0)-len(i+ljraquo(2de1)
else F(ij)=(len(ij)+len(i+lj+l)-len(ij+l)-len(i+ljraquo(2del)
endif sum=sum+F(ij)
30 continue 20 continue
c Determine viewfactors for all other surfaces do 40 iON-l
do 50 j=03N-l F(i+Nj+N)=F(ij)
50 continue do 60 j=3Nnsurf
F(i+Nj-3N)=F(ij) 60 continue
do 70 j=02N-1 F(i+2Nj+2N)=F(ij)
70 continue do 80 j=2Nnsurf
F(i+2Nj-2N)=F(ij) 80 continue
do 90 j=ON-l F(i+3Nj+3N)=F(ij)
90 continue do 100 j=Nnsurf
F(i+3Nj-N)=F(ij) 100 continue
40 continue
return end
c----------------------------------------------------------------------shyc-----------------------------------------------------------------------
Subroutine Jsolver(FemmissigmaTNNNWnsurfradlradEb + bvectorAmatrix)
integer NNNnsurfij real emmissigmaF(OnsurfOnsurf) real T(-INN+10NN)rad1(nsurf+l)rad(0nsurf) real Eb(0nsurf)bvector(nsurf+1)Amatrix(nsurf+lnsurf+l)surn
c Compute Eb for all surfaces do 10 i-ON-l
Eb(i)=sigma(T(i+WW) 4) Eb(i+N)=sigma(T(W+Ni+W)4)
10 continue incr=W+N do 20 i=0N-1
Eb(i+2N)=siqrna(T(incrW+N) 4) Eb(i+3N)=sigma(T(Wincr)4) incr=incr-1
20 continue
131
c Assign values to vector b do 30 i=Onsurf
bvector(i+l)-(emmis(l-emmisraquoEb(i) 30 continue
c Assign values to matrix A do 40 i-Onsurf
do SO j=Onsurf Amatrix(i+lj+l)--F(ij)
SO continue 40 continue
c Override diagonal terms do 60 i-Onsurf
sum-OO do 70 j-Onsurf
sum-sum+F(ij) 70 continue
Amatrix(i+li+l)-(emmis(l-emmisraquo+sum 60 continue
c Call routine to solve the set of equations for unknown JS call gaussy(Amatrixbvectorradlnsurf+l)
do 80 i=Onsurf rad(i)=radl(i+l)
80 continue
return end
c----------------------------------------------------------------------shyc-----------------------------------------------------------------------
Subroutine Gaussy(abxn) c
integer nkiimaxjkplusllplus real a(nn)b(n)x(n)amaxbtempatemp
+ aeon sum
do 28 k=l n amax=OO do 4 i=kn if(abs(a(ikraquo-abs(amaxraquo442
2 amax=a(ik) imax=i
4 continue if(abs(amax)-0le-15)101014
10 printO equations are not independent return
14 btemp=b(k) b(k)=b(imax) b(imax)=btemp do 18 j=kn
atemp=a(k j) a(kj)=a(imaxj)
18 a(imaxj)=atemp kplus=k+l if(k-n)222828
22 do 24 i=kplusn b(i)=b(i)-b(k)a(ik)a(kk) acon=a(ik) do 24 j=kn
24 a(ij)=a(ij)-a(kj)acona(kk) 28 continue
132
l=n 32 sum=OO
if(1-n)343838 34 lplus-1+1
do 36 j-lplusn 36 sum=sum+a(lj)x(j) 38 continue
x(l)-(b(l)-sum)a(ll) if(1-1)424240
40 1-1-1 goto 32
42 return end
c----------------------------------------------------------------------shyc-----------------------------------------------------------------------
Subroutine sseqn(TriplusriminusrjplusrjminusAiplus + AiminusAjplusAjminusijNN)
c This subroutine computes the temperature at node (ij) c given the temperatures of the surrounding nodes and c the resistances leading to these nodes
integer ijNN real T(-1NN+10NN)riplusriminusrjplusrjminus real AiplusAiminusAjplusAjminus real c1c2c3c4c5
c1=Aiplusriplus c2=Aiminusriminus c3=Ajplusrjplus c4=Ajminusrjminus c5=1(c1+c2+c3+c4)
T(ij)=c5(c1T(i+1j)+c2T(i-1j)+c3T(ij+1)+c4T(ij-1raquo
return end
c----------------------------------------------------------------------shyc----------------------------------------------------------------------shy
real function f1(x) c door BC
real x f1-18520 - 23413x
return end
c----------------------------------------------------------------------shyc----------------------------------------------------------------------shy
real function f2(x) c wall BC
real x f2=18128 - 3475x
return end
c----------------------------------------------------------------------shyc----------------------------------------------------------------------shy
133
Fresh Food Compartment Simulations Results
Run 1 The prescribed temperature profiles are
Wall 19203 - 1908 x Door 19203 - 1206 x
(x is in meters)
Outdoor Ambient = 210 degC Local Indoor Ambient = 1533 degC
Run 2 The prescribed temperature profiles are
Wall 18989 - 2024 x Door 19078 - 1326 x
(x is in meters)
Outdoor Ambient = 210 degC Local Indoor Ambient = 1496 degC
Run 3 The prescribed temperature profiles are
Wall 1895 - 1998 x Door 19053 - 1384 x
(x is in meters)
Outdoor Ambient = 208 degC Local Indoor Ambient = 1491 degC
Ayem~ Values Wall 1905 - 1977 x Door 1913 - 1384 x
(x is in meters)
Ave Outdoor Ambient = 209 degC Ave Local Indoor Ambient =1507 degC
Loss from Fresh Food == 10 W
134
Freezer Compartment Simulations Results
Run 1 The prescribed temperature profiles are
Wall 1821 - 343 x Door 18606 - 2354 x
(x is in meters)
Outdoor Ambient = 210 degC Local Indoor Ambient = 1029 degC
Run 2 The prescribed temperature profiles are
Wall 18182 - 3542 x Door 18544 - 2398 x
(x is in meters)
Outdoor Ambient = 210 degC Local Indoor Ambient = 1042 degC
Run 3 The prescribed temperature profiles are
Wall 17993 - 3452 x Door 18411 - 2272 x
(x is in meters)
Outdoor Ambient = 208 degC Local Indoor Ambient = 1024 degC
Ayera~e Values Wall 18128 - 3475 x Door 18520 - 23413 x
(x is in meters)
Ave Outdoor Ambient = 209 degC Ave Local Indoor Ambient = 1032 degC
Loss from Fresh Food = 157 W
135