For the chiller electric input ratio as a function of part load ratio chiller curve, IES-VE and eQuest both use EIRfPLR&dT, a bi-quadratic curve which requires 6 coefficients (a-f) and has two variables, PLR and lift (dT, ECWT and LCHWT).

But for Chiller:Electric:EIR EnergyPlus seems to only allow "EIRfPLR" as a quadratic curve, with only one variable, PLR, and 3 coefficients (a-c).

It then doesn't appear that its possible to use use the same curve fits in IES-VE or eQuest as it is in EnergyPlus. There is a third option using Chiller:Electric:ReforumlatedEIRbut that equation is either bi-cubic, and depending on LCWT (not ECWT) and PLR, or a custom curve dependent on dT* and T*dev.

I found this because I created custom chiller curves for use in IES-VE, and wanted to run some tests in EnergyPlus, but found it wouldn't accept my bi-quadratic curve.

Can someone explain the theory behind why one of these curve fits should be used over another and which one is 'better', and confirm that its not possible to use the same curve in all softwares? Unless you are using, the EIRfPLR quadratic curve only since you can always use fewer coefficients, but not more.

For the chiller electric input ratio as a function of part load ratio chiller curve, IES-VE and eQuest both use EIRfPLR&dT, a bi-quadratic curve which requires 6 coefficients (a-f) and has two variables, PLR and lift (dT, ECWT and LCHWT).

But for Chiller:Electric:EIR EnergyPlus seems to only allow "EIRfPLR" as a quadratic curve, with only one variable, PLR, and 3 coefficients (a-c).

It then doesn't appear that its possible to use use the same came curve fits in IES-VE or eQuest as it is in EnergyPlus. There is a third option using Chiller:Electric:ReforumlatedEIRbut that equation is either bi-cubic, and depending on LCWT (not ECWT) and PLR, or a custom curve dependent on dT* and T*dev.

Can someone explain the theory behind why one of these curve fits should be used over another and which one is 'better', and confirm that its not possible to use the same curve in all softwares? Unless you are using, the EIRfPLR quadratic curve only since you can always use fewer coefficients, but not more.'better'?

For the chiller electric input ratio as a function of part load ratio chiller curve, IES-VE and eQuest both use EIRfPLR&dT, a bi-quadratic curve which requires 6 coefficients (a-f) and has two variables, PLR and lift (dT, ECWT and LCHWT).

(dT). But for Chiller:Electric:EIR "Chiller:Electric:EIR" EnergyPlus seems to only allow "EIRfPLR" as a quadratic bicubic curve, with only one variable, PLR, and 3 coefficients (a-c).

It then doesn't appear that its possible to use use the came curve fits in IES-VE or eQuest as it is in EnergyPlus. There is a third option using Chiller:Electric:ReforumlatedEIRbut that equation is either bi-cubic, and depending on LCWT (not ECWT) and PLR, or a custom curve dependent on dT* and T*dev.

coefficients. Can someone explain the theory behind why one of these curve fits should be used over another and which one is 'better'?

For the chiller electric input ratio as a function of part load ratio chiller curve, IES-VE and eQuest both use EIRfPLR&dT, a bi-quadratic curve which requires 6 coefficients (a-f) and has two variables, PLR and lift (dT). curve. But for "Chiller:Electric:EIR" EnergyPlus seems to only allow "EIRfPLR" EIRfPLR as a bicubic curve, with only one variable, PLR, and 3 coefficients. curve. Can someone explain the theory behind why one of these curve fits should be used over another and which one is 'better'?'better'?