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Equation solvers. Matlab Free versions / open source codes: Scilab http://www.scilab.org/ MathCad: Mathematica: http://www.wolfram.com/mathematica/ LabView: http://www.ni.com/labview/ EES: http://www.fchart.com/ees/ Modelica: https://www.modelica.org/ …. Open Studio Lab Class. - PowerPoint PPT Presentation
Equation solvers
• Matlab
• Free versions / open source codes:
–Scilab http://www.scilab.org/
• MathCad:• Mathematica: http://www.wolfram.com/mathematica/
• LabView: http://www.ni.com/labview/
• EES: http://www.fchart.com/ees/
• Modelica: https://www.modelica.org/
• ….
Open Studio Lab Class
• This Thursday 4 pm
• Computer lab ECJ 3.402
• Instructor: Wesley Cole
Lecture Objectives:
• Building-System-Plant connection
Building-System-Plant
Plant(boilerand/orChiller)
Building
HVAC System(AHU and distribution systems)
Building HVAC Systems (Primary and Secondary Building Systems)
AHU
Buildingenvelope
Cooling(chiller)
(or Gas)
Electricity
Gas
Heating(boilers)
Fresh air For ventilation
Distribution systems
Air transport
Secondary systems
Primarysystems
AHU – Air Handling Unit
HVAC systems affect the energy efficiency of the building as much as the building envelope
Air-conditioning in Air Handling Unit (AHU)
Compressorand Condenser
Roof top AHU
Gas/Electric Heater
to building
Fan
air from building
fresh air
Evaporator
filtermixing
hotwatercool
water
Return fan
Supply fan
flow control dampers
AHU
Fresh air
AHU schematic
Outdoor air To room
Exhaust From room
Processes in AHU presented in Psychrometric in psychrometric
OA Case forSummer in Austin
IA
MA
SA
Refrigeration Cycle
T outdoor air
T cooled water
Cooling energy (evaporator)
Released energy (condenser)
- What is COP?- How the outdoor air temperature affects chiller performance?
Integration of HVAC and building physics models
BuildingHeating/Cooling
SystemPlant
BuildingHeating/Cooling
SystemPlant
Load System Plant model
Integrated models
Qbuiolding Q
including
Ventilation
and
Dehumidification
Example of System Models:Schematic of simple air handling unit (AHU)
rmSfans
cooler heater
mS
QC QH
wO wS
TR
room TR
Qroom_sensibel
(1-r)mS mS
wM
wR
Qroom_latent
TSTO
wR
TM
Tf,inTf,out
m - mass flow rate [kg/s], T – temperature [C], w [kgmoist/kgdry air], r - recirculation rate [-], Q energy/time [W]
Mixing box
Energy and mass balance equations for Air handling unit model – steady state case
SRpSsensibleroom TTcmQ _
mS is the supply air mass flow rate
cp - specific capacity for air,
TR is the room temperature,
TS is the supply air temperature.
changephaseSRSlatentroom iwwmQ __ wR and wS are room and supply humidity ratio
changephasei _ - energy for phase change of water into vapor
The energy balance for the room is given as:
The air-humidity balance for room is given as:
The energy balance for the mixing box is:
ROM TrTrT )1(‘r’ is the re-circulated air portion, TO is the outdoor air temperature, TM is the temperature of the air after the mixing box.
The air-humidity balance for the mixing box is:
ROM wrwrw )1(wO is the outdoor air humidity ratio and
wM is the humidity ratio after the mixing box
)( MSpSHeating TTcmQ
The energy balance for the heating coil is given as:
The energy balance for the cooling coil is given as:
changephaseMSSMSpSCooling iwwmTTcmQ _)(
Non-air system Radiant panel heat transfer model
Room (zone 1)
Radiant Panelc onv ecti
onTsurface
Tsurounding
Tzone_air rad iat ion
Qrad_pan
radiant panel layer (water tube)
air supplysystem
m ,T = const.s s
Qzone
Tw_out Tw_in
Non-air system Radiant panel heat transfer model
)()( __sup_sup airroomairplyairplypair TTmcQ
panradQ _
airpanradzone QQQ _
)()( ,,_ airpanelpanelconvisurfacepanelpaneliradiationconvradiationpanrad TTAhTTAhQQQ
)( ___ inwoutwpwpanrad TTmcQ
The total cooling/heating load in the room
The energy extracted/added by air system
The energy extracted/added by the radiant panel:
The radiant panel energy is:
The energy extracted/added by the radiant panel is the sum of the radiative and convective parts: