Jallen's profile - activity

Today I found a bug related to window construction of E+. When I added an adiabatic window construction (with very low solar transmittance, very high solar reflectance and very low conductivity ) into a residential building IDF file, even though I did not use this adiabatic window construction for fenestration (just keep this construction in the IDF file), I got different building energy simulation results from the case that did not include the adiabatic window construction in the IDF. In other words, the window construction itself could affect the building energy simulation results even though I did not use this window construction in fenestration (FenestrationSurface:Detailed) at all but just include it in the IDF file. That is unbelievable. The difference is about 2%.

I tested this problem using E+ 8.5 and E+ 8.6. If you guys need more detailed info, I can share my IDF file with you for finding out the problem.

Julien, thanks for your answer. I have checked the v8.3 release note but did not find the answer for my question. I also checked the coils sizes for the both versions, the autosized capacities and flow rates were the same for E+8.2 and E+8.3. Actually, I found the only difference was in the heating electrical energy consumption, the cooling electrical energy consumption was the same.

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.