Open dmey opened 7 months ago
@dmey - I don't see a defect file. Could you please upload one? Thanks!
The
HeatingCapacityMultiplier
forCalcMultiSpeedDXCoilHeating
is applied and backed out but in CalcDXHeatingCoil it is just applied.
I think that you may be looking at older code (at least 3 years old). The latest code shows that the multiplier is not applied to TotCap
but to TotCapAdj
. The latter is used to calculated the coil's PLR but the former is used for the power calculation. I think that this is consistent with what is expected and what you recommend. If you can upload your defect file I'd be happy to update it and run it with the latest code to make sure that this indeed is not an issue anymore.
@rraustad, @nmerket, @ejhw, and @lymereJ I noticed that there was an issue several years ago for
CalcMultiSpeedDXCoilHeating
(https://github.com/NREL/EnergyPlus/issues/4973) describing what appears to be the same issue (fixed in https://github.com/NREL/EnergyPlus/pull/5025). However, #5025 fixesCalcMultiSpeedDXCoilHeating
but notCalcDXHeatingCoil
. CompareCalcMultiSpeedDXCoilHeating
by https://github.com/NREL/EnergyPlus/commit/265573c7e60724d988ea80b98b7525b7d09c00f0https://github.com/NREL/EnergyPlus/blob/265573c7e60724d988ea80b98b7525b7d09c00f0/src/EnergyPlus/DXCoils.cc#L10902
vs CalcDXHeatingCoil
https://github.com/NREL/EnergyPlus/blob/265573c7e60724d988ea80b98b7525b7d09c00f0/src/EnergyPlus/DXCoils.cc#L8492)
The
HeatingCapacityMultiplier
forCalcMultiSpeedDXCoilHeating
is applied and backed out but in CalcDXHeatingCoil it is just applied.I think that
ElecHeatingPower
should be computed asDXCoil( DXCoilNum ).ElecHeatingPower = TotCap / HeatingCapacityMultiplier * EIR * DXCoil( DXCoilNum ).HeatingCoilRuntimeFraction * InputPowerMultiplier;
in both cases as the compressor is still working at full power but the system's efficiency goes down due to defrost/colder temperatures.Assuming a capacity of 3 kW and defrost of 1 kW, the following plots show the results before and after this proposed change for
CalcDXHeatingCoil
ElecHeatingPower = TotCap * HeatingCapacityMultiplier * EIR * HeatingCoilRuntimeFraction * InputPowerMultiplier;
ElecHeatingPower = TotCap / HeatingCapacityMultiplier * EIR * HeatingCoilRuntimeFraction * InputPowerMultiplier;