Defrost EIR Func of Temp Curve default

[mdahlhausen]

The default Defrost EIR Func of Temp Curve in Prototype.CoilHeatingDXSingleSpeed is set to cooling coil rating conditions, not heating coil rating conditions. The output value should be 1.0 at rating conditions of 8.33°C outdoor air dry-bulb temperature and 15.55°C heating coil entering air wet-bulb temperature. With the current coefficients, the value is 0.689788.

[dmey]

Hi @mdahlhausen, I was looking for Defrost EIR Func Temp Curve to use for the Single-Speed Electric Heat Pump DX Air Heating Coil but could not find them in the EnergyPlus repo together with these. I came across this issue and it looks like you are using defrost curves but could not find any reference for them. Could you please let me know where these come from and if they can be used with these? Thanks

[dmey]

Hi @mdahlhausen, just wondering if you had a change to look at this. I am a bit blocked with this at the moment. Thanks.

[mdahlhausen]

@dmey This issue relates to an error with the defrost curve giving an incorrect value at rated conditions. So don't use the curve as is in openstudio-standards. If you can't wait until this issue is addressed in a future release of openstudio-standards, I suggest getting some equipment performance data from a manufacturer and generating your own curve.

[dmey]

@mdahlhausen, I was mainly wondering where these were taken from as I could not find any references for them. For exampke the EIR and Flow curves are from here however Defrost EIR Func of Temp Curve are not reported.:

!  These coefficients were taken directly from the report below. For further details users may need
!  to refer this report.
!  D. Cutler, J. Winkler, N. Kruis, and C. Christensen
!  National Renewable Energy Laboratory
!  M. Brandemuehl
!  University of Colorado
!
!  Improved Modeling of Residential Air Conditioners and Heat Pumps for Energy Calculations
!
!  Technical Report
!  NREL/TP-5500-56354
!  January 2013