Energyplus CentralHeatPumpSystem / ChillerHeater Misconduct

asked 2023-06-12 15:37:57 -0500

SD's avatar

updated 2023-06-12 16:06:34 -0500

The ChillerHeater system in the latest versions seem to have some issue while in heating or simulataneous htg/clg mode. I read through couple of threads on unmet hours and Github but did not find any resolution for those. After noticing the misconduct in my detailed complex model, I just carried out the simulation for the example file in EnergyPlus 'CentralChillerHeaterSystem_Simultaneous_Cooling_Heating' and noticed similar misbehavior. The issue I notice is whenever it is running in mode '2 (Heating Only)' the electricity consumption is too high, i.e. it kind of runs at full capacity even at low loads. The EIR as fuct of PRL in the output shows always ~0.99 regardless of the load on that module. Thus the electricity consumption is too high for even small loads. This issue can be more easily spotted if system timestep is made same as zone timestep so that there is no averaging due to timestep difference. I saw similar issue was reported at

Also, in mode '3(simultaneous)' for many hours it does not report any electricity in either heating or cooling, i.e. zero electric consumption but still meeting load. That especially happens when the PLR is <0.85 (never at PLR 1). This issue is more pronounced in larger model but still there in example file. I saw similar issue was reported Attached some graphs to show the issue. C:\fakepath\1.JPG C:\fakepath\2.JPG

Is there any aspect that I am missing or is it still a pending issue? Thanks in advance!

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