Unexpected Results from Output:Meter:EnergyTransfer

[AmberJiayuSu]

Issue overview

I am encountering unexpected results when using the following output meters:

• Output:Meter,Heating:EnergyTransfer:Zone:*,Hourly;
• Output:Meter,Cooling:EnergyTransfer:Zone:*,Hourly;.

I am trying to estimate overall COP of heating and cooling system by calculating sum of energy supply into zones / energy used at the site/system level. Based on my understanding, EnergyTransfer:Zone: should represent the actual energy supplied to each zone.

The heating system in this case is modeled with an Ideal Loads Air System. Below are the plotted results:

1.Heating:DistrictHeating

2.Summation of Zone Ideal Loads Supply Air Total Heating Energy

3.Summation of EnergyTransfer:Zone:

While the summation of Zone Ideal Loads Supply Air Total Heating Energy and Heating:DistrictHeating matches. , there is a significant temporal and magnitude mismatch between the EnergyTransfer:Zone: results and the heating demand at the site level.

Is this discrepancy between the EnergyTransfer:Zone: values and the heating consumed at the site level expected? How should I interpret the difference in the results? Would this be a reasonable way to approach this COP calculation problem?

Details

Some additional details for this issue (if relevant):

• EnergyPlus 23.1

Thank you in advance for any guidance or explanation!

[mjwitte]

EnergyTransfer meters can be confusing, and sometimes they include overlapping values. The components of every meter are reported in the mtd output file. Search this file for the meter name and it will list all of the output variables that feed into it.