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I found two causes.
- Evaporator leaving water temperature and Condenser entering water temperature are different between Engineering Reference and actual code of EnergyPlus.
I summarised in the table below. The code says it follows AHRI 551/591-2011, but actually Evaporator leaving water temperature and Condenser entering water temperature at 75% load are different from AHRI 551/591.
The code on lines 341 and 342 is weird. I think this is a bug.
- Part Load Ratio
This is my mistake. It's confusing that there are two different parameters: ReducedPLR and PartLoadRatio . ReducedPLR is 100%, 75%, 50% and 25%. PartLoadRatio = ReducedPLR / ChillerCapFT.
I revised my excel calculation according to the current code. The calculated IPLV became very close to the reported IPLV, but still there is a slight difference (Hundredth's place is sometimes different). I'm still waiting for suggestions.
P.S.
When I changed the coefficients of two Biquadratic curves from the default centrifugal chiller to the default screw chiller, the difference between the calculated IPLV and the reported IPLV exceeded 1% again. My excel is not perfect...
I found two causes.
- Evaporator leaving water temperature and Condenser entering water temperature are different between Engineering Reference and actual code of EnergyPlus.
I summarised in the table below. The code says it follows AHRI 551/591-2011, but actually Evaporator leaving water temperature and Condenser entering water temperature at 75% load are different from AHRI 551/591.
The code on lines 341 and 342 is weird. I think this is a bug.
- Part Load Ratio
This is my mistake. It's confusing that there are two different parameters: ReducedPLR and PartLoadRatio . ReducedPLR is 100%, 75%, 50% and 25%. PartLoadRatio = ReducedPLR / ChillerCapFT.
I revised my excel calculation according to the current code. The calculated IPLV became very close to the reported IPLV, but still there is a slight difference (Hundredth's place is sometimes different). I'm still waiting for suggestions.
P.S.
When I changed the coefficients of two Biquadratic curves from the default centrifugal chiller to the default screw chiller, the difference between the calculated IPLV and the reported IPLV exceeded 1% again. My excel is not perfect...
suggestions.
I found two causes.
- Evaporator leaving water temperature and Condenser entering water temperature are different between Engineering Reference and actual code of EnergyPlus.
I summarised in the table below. The code says it follows AHRI 551/591-2011, but actually Evaporator leaving water temperature and Condenser entering water temperature at 75% load are different from AHRI 551/591.
The code on lines 341 and 342340 and 341 is weird. I think this is a bug.
- Part Load Ratio
This is my mistake. It's confusing that there are two different parameters: ReducedPLR and PartLoadRatio . ReducedPLR is 100%, 75%, 50% and 25%. PartLoadRatio = ReducedPLR / ChillerCapFT.
I revised my excel calculation according to the current code. The calculated IPLV became very close to the reported IPLV, but still there is a slight difference (Hundredth's place is sometimes different). I'm still waiting for suggestions.