chiller power consumption calculation

[chenjuncheng00]

I'm not sure if this is a bug or a calculated feature that I don't understand. Buildings.Fluid.Chillers.BaseClasses.PartialElectric, line144, buildings library version=9.1.0 // Compressor power. P = - QEva_flow_ava / COP_nominal EIRFunT EIRFunPLR CR; EIRFunT: proportion of cooling COP as a function of chilled water outlet temperature and cooling water return temperature; EIRFunPLR: proportion of cooling COP as a function of partial load factor; I think that if the chiller's rated chilled water discharge temperature is 7 degrees Celsius and the setting at this point is 9 degrees Celsius, assuming that the COP at this point is 1.1 times the rated COP, then EIRFunT=1.1; At this point the formula should be P = - QEva_flow_ava / (COP_nominal EIRFunT EIRFunPLR) CR; Am I understanding you correctly?

[mwetter]

I don't see an error in the implementation. See for example the EnergyPlus Engineering Reference, or the source code of EnergyPlus at https://github.com/NREL/EnergyPlus/blob/d5cec9178bd6a7abc8399f1df2de7a7980dda697/src/EnergyPlus/ChillerElectricEIR.cc#L2235 which is the same equation as is used in https://github.com/lbl-srg/modelica-buildings/blob/cf11ed882851670684cf615f4adb440edef8f73f/Buildings/Fluid/Chillers/BaseClasses/PartialElectric.mo#L187

[chenjuncheng00]

In Building Library, should the parameter EIRFunT be increased if the chilled water discharge temperature of the chiller increases? Or should it be reduced.

[hcasperfu]

@chenjuncheng00 - Greetings! I know this doesn't directly answer your question. This formula is implemented in the library as-is from DOE-2.1 and EnergyPlus. These formulae can be found in EnergyPlus Engineering Reference section 14.3.9.2. And especially see equation 14.240.

I have opened a PR to add this reference to the chiller model documentation.