Upload
ubaid-ur-rehman
View
238
Download
2
Embed Size (px)
Citation preview
8/11/2019 Solar Absorption Refrigeration
1/49
8/11/2019 Solar Absorption Refrigeration
2/49
8/11/2019 Solar Absorption Refrigeration
3/49
Group Members
ASIF IQBAL 10-MC-28
HAMZA JAVED 10-MC-54 UBAID-UR-REHMAN 10-MC-56 ZIA MUHAMMAD 10-MC-58 SAAD HANIF 10-MC-60
8/11/2019 Solar Absorption Refrigeration
4/49
CONTENTS1. INTRODUCTION2. LITERATURE REVIEW3. MATERIALS AND METHODS
4. PRINCIPLE5. WORKING6. DESIGN AND CALCULATIONS7. RESULT AND DISCUSSION8. CONCLUSION9. REFERENCES
8/11/2019 Solar Absorption Refrigeration
5/49
INTRODUCTION
8/11/2019 Solar Absorption Refrigeration
6/49
REFRIGERATION Refrigeration is a process in which work is done to
move heat from one location to another.
The work of heat transport is traditionally driven by mechanical work.
Refrigeration has many applications:household refrigerators, industrial freezers, airconditioning, heat pumps etc.
8/11/2019 Solar Absorption Refrigeration
7/49
METHODS OF REFRIGERATION
There are two methods of refrigeration:
Vapour Compression Refrigeration Vapour Absorption Refrigeration
8/11/2019 Solar Absorption Refrigeration
8/49
8/11/2019 Solar Absorption Refrigeration
9/49
TYPES OF ABSORPTION REFRIGERATION
Absorption machines are commercially available todayin two basic configurations.
LITHIUM BROMIDE/WATER Refrigeration CycleAbove 32F (primarily air conditioning), the cycle useslithium bromide as the absorbent and water as therefrigerant.
AMMONIA/WATER Refrigeration CycleBelow 32F, an ammonia/water cycle is employed withammonia as the refrigerant and water as the absorbent.
8/11/2019 Solar Absorption Refrigeration
10/49
8/11/2019 Solar Absorption Refrigeration
11/49
LITERATURE REVIEW Absorption cooling was invented by the French scientist
Ferdinand in 1858. The original design used water and sulfuricacid.
Ali zadeh carried out theoretical study on design andoptimization of water lithium bromide refrigeration cycle.
Tyagi carried out the detailed study on aqua-ammonia VARsystem
Talbi and Agnew carried our energy analysis on single effectabsorption refrigeration cycle with lithium bromide water as theworking fluid pairs. The cycle collects free energy from theexhaust of diesel engine.
8/11/2019 Solar Absorption Refrigeration
12/49
8/11/2019 Solar Absorption Refrigeration
13/49
MATERIALS AND METHODS
8/11/2019 Solar Absorption Refrigeration
14/49
EVAPORATOR
Heat energy is absorbed by the refrigerant vaporizingat low pressure and saturation temperature.
The low-pressure refrigerant vapour is drawn to the
absorber.
8/11/2019 Solar Absorption Refrigeration
15/49
ABSORBER
The concentrated absorbent is cooled and mixed with thelow-pressure refrigerant resulting in a weak solution. Thisweak solution is transferred to the generator to complete
the cycle.
8/11/2019 Solar Absorption Refrigeration
16/49
GENERATOR
Heating source Separation of the refrigerant
from the absorber The pure concentrated absorbent passes to the absorber vessel.The heat applied to the generator
also generates the high side pressure of the system.
8/11/2019 Solar Absorption Refrigeration
17/49
CONDENSER
Rejects heat from the refrigerant, causing therefrigerant to de-superheat and condense to liquidform.
The liquid refrigerant then passes to the evaporator.
8/11/2019 Solar Absorption Refrigeration
18/49
ABSORPTION REFRIGERATOR
8/11/2019 Solar Absorption Refrigeration
19/49
SOLAR GEYSER
It is a device using solar radiation to heat water. The solar water heaters employ the natural convection
phenomenon called thermo syphon , which results in hot water being lighter than cold water.
The water heated in water tubes rises through the solar collectorto enter storage tank , while the cold water at the bottom of the
tank flows in tubes creating continues circulation.
8/11/2019 Solar Absorption Refrigeration
20/49
8/11/2019 Solar Absorption Refrigeration
21/49
REFRIGERANT Anhydrous ammonia is a clear, colorless liquid or gas, free from
visible impurities. It is at least 99.95 percent pure ammonia.
Boiling Point -28 F Vapor pressure at 0 F 16 psi Vapor pressure at 68 F 110 psi Vapor pressure at 100 F 198 psi
8/11/2019 Solar Absorption Refrigeration
22/49
8/11/2019 Solar Absorption Refrigeration
23/49
PRINCIPLE
8/11/2019 Solar Absorption Refrigeration
24/49
PRINCIPLE
Dalton's Law of Partial PressuresThe total pressure of a mixture of gases is equal to thesum of the partial pressures of the component gases.
PressureTotal
= PressureGas 1
+ PressureGas 2
+
Pressure Gas 3 + ... Pressure Gas n
8/11/2019 Solar Absorption Refrigeration
25/49
THREE FLUIDS ABSORPTION SYSTEM
This type of refrigerator is also called Three-fluidsabsorption system . The three fluids used in this
system are:
1. AMMONIA
2. HYDROGEN3. WATER
8/11/2019 Solar Absorption Refrigeration
26/49
WORKING
8/11/2019 Solar Absorption Refrigeration
27/49
8/11/2019 Solar Absorption Refrigeration
28/49
8/11/2019 Solar Absorption Refrigeration
29/49
WORKING Strong ammonia chamber solution ready for boiling and
starting the cycle again.
8/11/2019 Solar Absorption Refrigeration
30/49
DESIGN AND CALCULATIONS
8/11/2019 Solar Absorption Refrigeration
31/49
DESIGN AND CALCULATIONS
Assumed for theoretical calculation Condenser pressure: 5 bar, Evaporator pressure: 2 bar, Capacity of refrigeration: 0.25 TR,
8/11/2019 Solar Absorption Refrigeration
32/49
DESIGN AND CALCULATIONS
8/11/2019 Solar Absorption Refrigeration
33/49
DESIGN OF CONDENSER
1) Mass flow rate of NH 3 through Condenser (m r ): m r = Cooling load/ h 1 h2
= (0.25x3.5)/(1632.462-376.722) m r = 6.968 10 -4kg/s
2) Heat removed in condenser (Q C): QC = m r (h 1- h 2)
= 6.968 x 10^-4 x (1632.462-376.722) QC = 0.875kW.
8/11/2019 Solar Absorption Refrigeration
34/49
8/11/2019 Solar Absorption Refrigeration
35/49
DESIGN OF CONDENSER We assume do=17.5mm di=16.5mm ho=16w/m.K hi=1833.76w/m.K K=17w/m.k Then U=15.85w/m.K
AS Q= [U*A*LMTD] A= DL Then L=Q/ (U* *d*LMTD)
L=0.21m
8/11/2019 Solar Absorption Refrigeration
36/49
DESIGN OF EVAPORATOR m f =6.968 10 -4kg/s Qe=m f *(h 4- h3)
=0.875KW
Temp. of air surrounding evaporator, Th i = 2 C Temp. of air after 1 min, Tc o = 3 C. Temp. of NH 3 liquid entering evaporator,Tc i =-18 C Temp. of NH 3 liquid leaving evaporator, Tc o=-15 C LMTD=4 C Overall heat transfer coefficient=U=19.59w/m.K Q= [U*A*LMTD]
L=0.22m
8/11/2019 Solar Absorption Refrigeration
37/49
DESIGN OF ABSORBER
ii) Heat rejected in absorber (Q a):Qa =1.31kw
Inlet temperature of water, Tc i = 23 C
Outlet temperature of water, Tc o = 25 C Temperature of NH 3 entering, Th i = 34 C Temperature of NH 3 leaving, Th o = 28 C LMTD=5.48 C U=21w/m.K Q = [ U*A*LMTD] L = 3.2m No. of turns=6
8/11/2019 Solar Absorption Refrigeration
38/49
DESIGN OF GENERATOR Original mass of the solutions are taken 15% more. Mass flow rate of weak solution entering into the generator from
absorber = 0.0015945* 1.15
= 0.001833 kg/s. Mass flow rate of strong solution going into the heat generator = 0.00186*1.15 = 0.00215kg/s Mass flow rate of water vapor leaving the generator = 0.00215-0.001833 = 0.0003163 kg/s. Total volume of vapor= m*specific volume Specific volume of vapor = 5.63 m 3/kg.
8/11/2019 Solar Absorption Refrigeration
39/49
DESIGN OF GENERATOR Total volume of vapor = 0.0003163*5.63
= 0.0017810 m 3/s. Total volume of strong solution = 0.00215* 0.0019
= 4.0861 * 10-6 m 3/s. Total volume of generator
= [volume of water vapor] +[volume of strong Solution]= 0.0017810+4.0861* 10-6= 1.7847*10-3 m 3/s.
Assuming 10% clearance
Volume generator = 1.983*10-3 m3
/s. But value = /4*dL /4*dL = 1.983*10-3 Therefore d= 8.75cm L=33cm
8/11/2019 Solar Absorption Refrigeration
40/49
COEFFICIENT OF PERFORMANCE
C.O.P=Heat absorbed in Evaporator Heat supplied in Generator
(C.O.P) MAX =(Te
TcT )( TgTcTg
) T
e=-16.5+273=256.5
Tc=44.5+273=317.5 Tg=60+273=333 C.O.P=0.195
8/11/2019 Solar Absorption Refrigeration
41/49
FAISALABAD LOCATION
1. Weather station FAISALABAD is at about31.42 0 N and 73.06 0E.
2. Height about 184m/603 feet above sees level.3. Region: Punjab4. Country: Pakistan5. Latitude: 31.4166667
8/11/2019 Solar Absorption Refrigeration
42/49
CLIMATE CONDITION FAISALABAD 24-hr average temperature
Thermal performance of Solar Geyser
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Year
0
C 11.7 14.7 19.8 26.0 31.4 34.1 32.5 31.6 30.2 25.6 19.0 13.7 24.5
O
F 53.4 58.5 67.6 78.8 88.5 93.4 90.5 88.9 86.4 78.1 66.2 56.7 76.1
Time (hrs) Ambienttemp.
0C
Inlet temp.0C
Outlet temp.0C
Storagetemp.
0C 9:00 34.08 26.35 42.07 42.09
10:00 37.50 27.05 52.25 54.02 11:00 39.21 29.50 65.35 64.66 12:00 40.93 31.35 76.55 74.23 1:00 42.05 33.47 85.07 83.70 2:00 43.07 34.08 87.15 85.69 3:00 39.45 30.03 82.58 80.39
4:00 35.25 28.17 78.63 77.05
8/11/2019 Solar Absorption Refrigeration
43/49
RESULT AND DISCUSSION
8/11/2019 Solar Absorption Refrigeration
44/49
8/11/2019 Solar Absorption Refrigeration
45/49
8/11/2019 Solar Absorption Refrigeration
46/49
CONCLUSION
8/11/2019 Solar Absorption Refrigeration
47/49
Conclusion
Absorption system has a proven history of providinglow-cost reliable cooling and should continue to do so
in the future.Absorption systems can provide significant energysavings for a particular application.
8/11/2019 Solar Absorption Refrigeration
48/49
REFERENCES
8/11/2019 Solar Absorption Refrigeration
49/49
REFERENCES Lavanya et al, International journal of advanced engineering
research and studies. ASHRAE Hand Book 1951(Tables of specific volume of aqua
ammonia solutions) John A. Duffie, 1991. William A.Beckman. Solar Engineering
Of thermal Processes. John Wiley & sons. Inc. Staicovici M. D.,(1986)" An Autonomous Solar Ammonia-
Water Refrigeration System", Solar Energy, Volume 36, Issue 2,1986, Pages 115-124
V.F. TCHAIKOVSKY. And A.P. KUTEZSOV, Utilisation ofrefrigerant mixtures in refrigerating compression machinery, Air Conditioning And Refrigeration in india. Vol.4,1964.