Question-and-Answer Resource for the Building Energy Modeling Community
 | 1 | initial version |
In EnergyPlus, there are two critical simulation runs, The Sizing Period and the RunPeriod. The RunPeriod is what we can refer to as the yearly simulation.
I can tell from your spreadsheet that you are looking at the zone peaks during the RunPeriod (because the date is either in July or August). All the auto-sized equipment is based on the results from the Sizing Period. So if you want to look at the output variables and relate them to the sizing, you should be looking at the values over the Sizing Period. To make it easier if you are working with the SQlite file, I like to turn off the RunPeriod.
Second, you do not need to back-calculate the cooling capacity provided by the chiller the RunPeriod. Instead, you can export the HVAC, Average, Chiller Evaporator Cooling Rate [W]. I would also export the HVAC, Average, Chiller COP [W/W] so that you can see that your chiller is most likely not performing at a COP of 6 during the simulation.
Finally, the sum of heat gains does not equal the cooling load. The variables that you are adding in the Peak Cooling Sensible Heat Gain Components section of your spreadsheet will not give you the cooling load (especially if you have a high-mass building). So if you do not want the peak sensible for each zone, you should export the Zone Predicted Sensible Load to Cooling Setpoint Transfer Rate and again look at it during the Sizing period.
| | 2 | No.2 Revision |
In EnergyPlus, there are two critical simulation runs, The Sizing Period and the RunPeriod. The RunPeriod is what we can refer to as the yearly simulation.
I can tell from your spreadsheet that you are looking at the zone peaks during the RunPeriod (because the date is either in July or August). All the auto-sized equipment is based on the results from the Sizing Period. So if you want to look at the output variables and relate them to the sizing, you should be looking at the values over the Sizing Period. To make it easier if you are working with the SQlite file, I like to turn off the RunPeriod.
Second, you do not need to back-calculate the cooling capacity provided by the chiller the RunPeriod. Instead, you can export the HVAC, Average, Chiller Evaporator Cooling Rate Rate [W]. I would also export the HVAC, Average, Chiller COP COP [W/W] so that you can see that your chiller is most likely not performing at a COP of 6 during the simulation.
Finally, the sum of heat gains does not equal the cooling load. The variables that you are adding in the Peak Cooling Sensible Heat Gain Components section of your spreadsheet will not give you the cooling load (especially if you have a high-mass building). So if you do not want the peak sensible for each zone, you should export the Zone Predicted Sensible Load to Cooling Setpoint Transfer Rate Rate and again look at it during the Sizing period.
