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21032103--454 Ventilation and Air Conditioning454 Ventilation and Air Conditioning
Cooling LoadCooling Load CalculationsCalculations
byby
Assist. Prof. Dr. Tul Assist. Prof. Dr. Tul ManewattanaManewattana.. ChulalongkornChulalongkorn UniversityUniversity
Bangkok, THAILANDBangkok, THAILAND
November 2010November 2010
22
Principles of Cooling LoadPrinciples of Cooling Load
33
Principles of Cooling LoadPrinciples of Cooling Load
44
Principles of Cooling LoadPrinciples of Cooling Load
55
Principles of Cooling LoadPrinciples of Cooling Load
66
Principles of Cooling LoadPrinciples of Cooling Load
77
Principles of Cooling LoadPrinciples of Cooling Load
88
Outdoor Design ConditionOutdoor Design Condition
99
Outdoor Design ConditionOutdoor Design Condition
1010
Outdoor Design ConditionOutdoor Design Condition
1111
Outdoor Design ConditionsOutdoor Design Conditions
1212
Indoor Design ConditionIndoor Design Condition
1313
Indoor Design ConditionIndoor Design Condition
1414
Components of Cooling LoadComponents of Cooling Load
1) External Load
2) Internal Load
3) Outdoor Air Load
1.1) Roofs
1.2) Wall
1.3) Glass (Windows)
1.4) Ceiling
1.5) Floor
1.6) Partition
2.1) People
2.2) Lights
2.3) Power
2.4) Appliances
1515
Lighting Heat GainLighting Heat Gain
1616
LightingLighting
Radiant-CL
41% Conv.59% Radiant
Heat Gain
Conv-CL
Total-CL
Sum
NS-RTS
Watt & Usage
Profile
1717
Cooling Load from LightsCooling Load from Lights
1818
Convective/Radiant SplitConvective/Radiant Split
1919
NonsolarNonsolar RTS ValuesRTS Values
2020
NonsolarNonsolar RTSRTS
2121
Cooling Load from LightsCooling Load from Lights
2222
Calculation ExampleCalculation Example
2323
Example of CalculationsExample of Calculations
2424
Plenum Heat BalancePlenum Heat Balance
2525
Approximate Watt/Approximate Watt/Sq.mSq.m
2626
Lighting Efficiency CompareLighting Efficiency Compare
2727
Wall Heat GainWall Heat Gain
2828
WallWallLocation &
Outside Design Conditions
Radiant-CL
37% Conv.63% Radiant
Heat GainHeat InputSol-air Temp
Conv-CL
Total-CL
Sum
Wall CTS
NS-RTS
2929
Solar Irradiance on WSolar Irradiance on W--WallWall
3030
Solar AngleSolar Angle
3131
Solar EquationsSolar Equations
3232
Solar Irradiance DataSolar Irradiance Data
3333
Earth OrbitEarth Orbit
3434
DeclinationDeclination
3535
WW--Wall Cooling LoadWall Cooling Load
3636
WW--Wall TimeWall Time--delay Effectdelay Effect
3737
SolSol--Air TemperatureAir Temperature
3838
SolSol--Air TemperatureAir Temperature
3939
SolSol--air Temperatureair Temperature
4040
Wall CTSWall CTS
4141
Wall CTSWall CTS
4242
UU--ValueValue
4343
Film Coefficient of AirFilm Coefficient of Air
4444
Air GapAir Gap
4545
KK--ValueValue
4646
UU--ValueValue
4747
UU--ValueValue
4848
UU--ValueValue
4949
Energy Efficient WallEnergy Efficient Wall
5050
Roof Heat GainRoof Heat Gain
5151
RoofRoofLocation &
Outside Design Conditions
Radiant-CL
16% Conv.84% Radiant
Heat GainHeat InputSol-air Temp
Conv-CL
Total-CL
Sum
Roof CTS
NS-RTS
5252
Roof CTSRoof CTS
5353
UU--ValueValue
5454
UU--ValueValue
5555
RR--Value of AtticsValue of Attics
5656
Partition/Floor/Ceiling Heat GainPartition/Floor/Ceiling Heat Gain
5757
Ceiling/Floor/PartitionCeiling/Floor/Partition
Radiant-CL
37% Conv.63% Radiant
Heat Gain
Conv-CL
Total-CL
Sum
NS-RTS
Heat Input CTS
5858
Partition/Ceiling/FloorPartition/Ceiling/Floor
5959
UU--ValueValue
6060
Temperature for Temperature for Adjacent Adjacent UncondUncond--RoomRoom
6161
Temperature forTemperature for Adjacent Adjacent UncondUncond--RoomRoom
6262
WINDOW HEAT GAINWINDOW HEAT GAIN
1) Window Conduction Heat Gain1) Window Conduction Heat Gain
2) Window Solar Heat Gain2) Window Solar Heat Gain
6363
WindowWindow--Solar #1Solar #1Location &
Outside Design Conditions
Radiant-CL
37% Conv.63% Radiant
Beam Heat Gain
Conv-CL
Total-CL
Sum
NS-RTS
Diffuse Heat Gain
100% Radiant
Heat Input - Solar Irradiance
(Direct, Diffuse, Reflect)
S-RTS
No Blinds or
Overhang
6464
WindowWindow--ConductionConductionOutside Design Conditions
Radiant-CL
37% Conv.63% Radiant
Heat GainOutside Air Temp
Conv-CL
Total-CL
Sum
NS-RTS
6565
WW--Window Heat GainWindow Heat Gain
6666
WW--Window CLWindow CL
6767
Beam Solar TimeBeam Solar Time--delay Effectdelay Effect
6868
Diff. Solar TimeDiff. Solar Time--delay Effectdelay Effect
6969
WW--Window CL ComponentsWindow CL Components
7070
Solar RTS ValuesSolar RTS Values
7171
SHGCSHGC
7272
UU--Factors for GlassFactors for Glass
7373
Insulating Glass Unit (IGU)Insulating Glass Unit (IGU)
7474
WindowWindow--Solar #2Solar #2Location &
Outside Design Conditions
Radiant-CL
37% Conv.63% Radiant
Beam Heat Gain x IAC
Conv-CL
Total-CL
Sum
NS-RTS
Diffuse Heat Gain x IAC
Heat Input - Solar Irradiance
(Direct, Diffuse, Reflect)
With Blinds No
Overhang
7575
WindowWindow--Solar #3Solar #3Location &
Outside Design Conditions
Radiant-CL
37% Conv.63% Radiant
Beam Heat Gain x IAC
Conv-CL
Total-CL
Sum
NS-RTS
Diffuse Heat Gain x IAC
Heat Input - Solar Irradiance
(Direct, Diffuse, Reflect)
With Blinds and
Overhang
Shading Fraction & EAC
7676
Venetian Blinds Venetian Blinds Shading Coefficients (IAC)Shading Coefficients (IAC)
7777
Venetian BlindsVenetian Blinds
7878
Draperies IACDraperies IAC
7979
DraperiesDraperies
8080
External ShadingExternal Shading
8181
External ShadingExternal Shading
8282
External ShadingExternal Shading
8383
People Heat GainPeople Heat Gain
8484
PeoplePeople
Radiant-CL
40-63% Conv.60-27% Radiant
Sensible
Heat Gain
Conv-CL
Total-CL
Sum
NS-RTS
Latent Heat Gain
Heat Gain Per Person &
Usage Profile
8585
People Heat GainPeople Heat Gain
8686
Occupant Density (PTT Bld.)Occupant Density (PTT Bld.)
8787
Motor Heat GainMotor Heat Gain (Power)(Power)
8888
Motor Heat GainMotor Heat Gain
8989
Appliances Heat GainAppliances Heat Gain
9090
EquipmentsEquipments
Radiant-CL
80-20% Conv.20-80% Radiant
Sensible
Heat Gain
Conv-CL
Total-CL
Sum
NS-RTS
Latent Heat Gain
Heat Gain Per Equipment & Usage Profile
Exhaust
Hood
9191
Heat Gain from EquipmentsHeat Gain from Equipments
9292
Hood Load FactorHood Load Factor
9393
Office Equipment Load FactorOffice Equipment Load Factor
9494
Actual Load FactorActual Load Factor
9595
Ventilation/Infiltration Heat GainVentilation/Infiltration Heat Gain
9696
Outside AirOutside Air
Sensible
Heat Gain
Total-CL
Sum
Latent Heat Gain
CFM, Design Conditions & Usage Profile
9797
Outdoor Air LoadOutdoor Air Load
9898
Ventilation CFM: Ventilation CFM: ASHRAE Standard 62ASHRAE Standard 62--20072007
9999
Example: Calculation of Ventilation Example: Calculation of Ventilation RateRate
100100
MiscellaneousMiscellaneous
101101
Duct Heat GainDuct Heat Gain
102102
Duct Leak LossDuct Leak Loss
103103
Duct Leakage ClassDuct Leakage Class
104104
Duct Heat Gain & Leak LossDuct Heat Gain & Leak Loss
Duct Heat Gain in % of RSHDuct Heat Gain in % of RSH --Supply Duct 1.5% (Typical Value)Supply Duct 1.5% (Typical Value) --Return Duct 1.5% (Typical Value)Return Duct 1.5% (Typical Value)
Duct Leakage in % of Total Air SupplyDuct Leakage in % of Total Air Supply --Supply Duct 3% (Typical Value)Supply Duct 3% (Typical Value) --Return Duct 0% (Typical Value)Return Duct 0% (Typical Value)
Note that these value are only approximated.Note that these value are only approximated.
105105
Effect of Internal MassEffect of Internal Mass
106106
Room Temperature VariationRoom Temperature Variation
107107
Diversity Factor & Block LoadDiversity Factor & Block Load
