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Cooling/heating loads breakup

asked 2015-07-23 14:33:56 -0500

rkbest gravatar image

updated 2015-11-10 21:31:05 -0500

I am trying to get hourly data for one year of cooling/heating loads from Energyplus simulation. What variables and frequency I need to get these exactly for 8760 hours with timestamp. The variable definitions do not detailed enough for my understanding. The other output I am looking for is the energy use by the outdoor unit for each zone (aggregate of multi-zone AHU).

I am bit lost with so many output variables for zone but few for hvac system .

I understand that I need to get these Cooling/heating aggregated Output:Variable,,VRF Heat Pump Terminal Unit Cooling Load Rate,hourly; !- HVAC Average [W] Output:Variable,,VRF Heat Pump Terminal Unit Heating Load Rate,hourly; !- HVAC Average [W] for Energy used Output:Variable,,VRF Heat Pump Heating Electric Energy,hourly; !- HVAC Sum [J] Output:Variable,,VRF Heat Pump Cooling Electric Energy,hourly; !- HVAC Sum [J]

Will these include all the energy used for the system like, compressor, condenser fan.

What variables are for the energy use by indoor AHU's

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answered 2015-07-23 15:09:19 -0500

The fist question regarding 8760 hours of data requires a reporting frequency of hourly. If you use Output:VariableDictionary,IDF; then the rdd file will show VRF related report variables as:

Output:Variable,*,Zone VRF Air Terminal Cooling Electric Power,hourly; !- HVAC Average [W]
Output:Variable,*,Zone VRF Air Terminal Cooling Electric Energy,hourly; !- HVAC Sum [J]
Output:Variable,*,Zone VRF Air Terminal Total Cooling Rate,hourly; !- HVAC Average [W]
Output:Variable,*,Zone VRF Air Terminal Sensible Cooling Rate,hourly; !- HVAC Average [W]
Output:Variable,*,Zone VRF Air Terminal Latent Cooling Rate,hourly; !- HVAC Average [W]
Output:Variable,*,Zone VRF Air Terminal Total Cooling Energy,hourly; !- HVAC Sum [J]
Output:Variable,*,Zone VRF Air Terminal Sensible Cooling Energy,hourly; !- HVAC Sum [J]
Output:Variable,*,Zone VRF Air Terminal Latent Cooling Energy,hourly; !- HVAC Sum [J]
Output:Variable,*,Zone VRF Air Terminal Heating Electric Power,hourly; !- HVAC Average [W]
Output:Variable,*,Zone VRF Air Terminal Heating Electric Energy,hourly; !- HVAC Sum [J]
Output:Variable,*,Zone VRF Air Terminal Total Heating Rate,hourly; !- HVAC Average [W]
Output:Variable,*,Zone VRF Air Terminal Sensible Heating Rate,hourly; !- HVAC Average [W]
Output:Variable,*,Zone VRF Air Terminal Latent Heating Rate,hourly; !- HVAC Average [W]
Output:Variable,*,Zone VRF Air Terminal Total Heating Energy,hourly; !- HVAC Sum [J]
Output:Variable,*,Zone VRF Air Terminal Sensible Heating Energy,hourly; !- HVAC Sum [J]
Output:Variable,*,Zone VRF Air Terminal Latent Heating Energy,hourly; !- HVAC Sum [J]
Output:Variable,*,Zone VRF Air Terminal Fan Availability Status,hourly; !- HVAC Average []
Output:Variable,*,VRF Heat Pump Total Cooling Rate,hourly; !- HVAC Average [W]
Output:Variable,*,VRF Heat Pump Total Heating Rate,hourly; !- HVAC Average [W]
Output:Variable,*,VRF Heat Pump Cooling Electric Power,hourly; !- HVAC Average [W]
Output:Variable,*,VRF Heat Pump Cooling Electric Energy,hourly; !- HVAC Sum [J]
Output:Variable,*,VRF Heat Pump Heating Electric Power,hourly; !- HVAC Average [W]
Output:Variable,*,VRF Heat Pump Heating Electric Energy,hourly; !- HVAC Sum [J]
Output:Variable,*,VRF Heat Pump Cooling COP,hourly; !- HVAC Average []
Output:Variable,*,VRF Heat Pump Heating COP,hourly; !- HVAC Average []
Output:Variable,*,VRF Heat Pump COP,hourly; !- HVAC Average []
Output:Variable,*,VRF Heat Pump Defrost Electric Power,hourly; !- HVAC Average [W]
Output:Variable,*,VRF Heat Pump Defrost Electric Energy,hourly; !- HVAC Sum [J]
Output:Variable,*,VRF Heat Pump Part Load Ratio,hourly; !- HVAC Average []
Output:Variable,*,VRF Heat Pump Runtime Fraction,hourly; !- HVAC Average []
Output:Variable,*,VRF Heat Pump Cycling Ratio,hourly; !- HVAC Average []
Output:Variable,*,VRF Heat Pump Operating Mode,hourly; !- HVAC Average []
Output:Variable,*,VRF Heat Pump Condenser Inlet Temperature,hourly; !- HVAC Average [C]
Output:Variable,*,VRF Heat Pump Maximum Capacity Cooling Rate,hourly; !- HVAC Average [W]
Output:Variable,*,VRF Heat Pump Maximum Capacity Heating Rate,hourly; !- HVAC Average [W]
Output:Variable,*,VRF Heat Pump Crankcase Heater Electric Power,hourly; !- HVAC Average [W]
Output:Variable,*,VRF Heat Pump Crankcase Heater Electric Energy,hourly; !- HVAC Sum [J]
Output:Variable,*,VRF Heat Pump Terminal Unit Cooling Load Rate,hourly; !- HVAC Average [W]
Output:Variable,*,VRF Heat Pump ...
(more)
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Comments

Thanks @rraustad. Can you elaborate on your comment:- "Note that these data will not actually show the cooling and heating loads unless the zone thermostat temperature set point is maintained, which is not likely with VRF systems."

rkbest gravatar imagerkbest ( 2015-07-24 14:08:17 -0500 )edit

The loads are somewhat meaningless if the space temperature deviates from the set point since the predicted load includes the capacity required to meet the set point. So if the set point is not met, the summed load will be exaggerated. Regarding VRF systems not maintaining the temperature set point, since there are times when heating and cooling are needed at the same time, when heat recovery is NOT used, some of the spaces will deviate from the set point. If heat recovery IS used, there is a better chance that all zones may meet the set point.

rraustad gravatar imagerraustad ( 2015-07-24 14:27:39 -0500 )edit

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Asked: 2015-07-23 14:33:56 -0500

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Last updated: Jul 23 '15