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How to know cooling energy removed by VRF system

asked 2017-10-06 02:41:22 -0500

katsuya.obara gravatar image

I am modelling with following template

HVACTemplate:Zone:VRF  
HVACTemplate:System:VRF  
HVACTemplate:System:DedicatedOutdoorAir

I want to know how much cooling energy is removed by VRF system.
When I implemented HVACTemplate:Plant:Chiller, I could export that data by Chiller Evaporator Cooling Energy. However, I cannot find similar component for VRF system.
(I could find VRF Heat Pump Total Cooling Rate.However, I prefer to look at energy instead of rate)
Can anyone tell me which data I can export and check it?

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answered 2017-10-07 09:37:31 -0500

The report data dictionary file (rdd) shows all available report variables for a specific simulation. I ran the example file VariableRefrigerantFlow_5Zone.idf and find these reports are available for VRF systems. Note that I changed the example file line Output:VariableDictionary,Regular; to Output:VariableDictionary,IDF; to get this format.

For the air terminals you want to use:

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]

or

Output:Variable,*,Zone VRF Air Terminal Heating Electric Energy,hourly; !- HVAC Sum [J]

Reviewing these available reports, I don't see an energy report for the VRF condenser. However, you can sum the terminal unit energy report variables to get the information you are interested in. Alternately, you can multiply the rate report variable by the fraction of time the report variable represents (e.g., hourly, timestep, etc.)

Output:Variable,*,VRF Heat Pump Total Cooling Rate, timestep; !- HVAC Average [W]

Example:

Timestep,4; !- Number of time steps per hour (a.k.a. TimeStepSys or system time step)

ReportingConstant = TimeStepSys * SecInHour;
ReportingConstant = 0.25 * 3600;
Energy (J) = Rate (W) * ReportingConstant;
Energy (J) = Rate (W) * 0.25 * 3600;

Be careful with this math when reporting at the detailed reporting frequency since the time of reports will be more frequent than the system time step.

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 ...
(more)
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Asked: 2017-10-06 02:41:22 -0500

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Last updated: Oct 07 '17