Why the heating coil electric energy of heat pump was different for the same case but with using E+ 8.2 and E+ 8.3?
I used E+8.2 and E+8.3 to run the same heat pump project, but the heating coil electric energy was significant different (larger than 12%). I checked the simulation results and found the only difference was in the "Heating Coil Electric Energy ", the other electricity uses, such as "Heating Coil Defrost Electric Energy ", "Heating Coil Crankcase Heater Electric Energy ", "Air System Heating Coil Total Heating Energy", were almost the same. Thus, I guessed the corrections of partial load performance curve of heat pump might be changed in new version of E+, then I further checked the Performance Curve Input Variable and the Output value, it was found that these values were really different in E+8.2 and E+8.3. The performance curves in different E+ were the same, can check the IDF file( object name: Curve:Quadratic,HPACCOOLPLFFPLR). All the input coefficients in this object are the same for E+8.2 and E+8.3, but the internal Input Variable and the Output value were changed. So, I suspected the E+ developers might change the internal algorithms in getting the Input Variable of part load performance, especially for the object "Sizing:System". From E+8.2 to E+8.3, the object of "Sizing:System" was improved, I am not sure if this is the reason that cause the different results in my simulation. Can anybody here answer my question?
I also run the build-in heat pump example file (HeatPump.idf) using E+8.2 and E+8.3, the same problem and difference was found.
