Energy simulation after using solve Adjc, Heating EUI is very small!

liuke · December 22, 2020, 6:52am

Hi everyone！
I encountered a strange problem.
I plan to simulate the energy consumption of a ten-story building, which is the experiment numbered 3 in the figure, but I found that the result of Heating EUI is very small. Furthermore, only the tenth floor of this building has heating load, and the heating load of other floors is zero. However, Cooling EUI is quite normal. According to the same building function, I set up two sets of comparative experiments. The first experiment is a one-story building. The second experiment is the same ten-story building, but without using the zero boundary tool. Although I think this simulation should be incorrect, the results seem to be reasonable.

liuke · December 22, 2020, 7:04am

building energy simulation.gh (819.2 KB)
Looking forward to receiving your suggestions

furtonb · December 23, 2020, 8:41am

hi @liuke,

Without solving adjacencies all your internal construction are considered “external”:

This is how it looks after solving adjacencies:

This is your “first” model:

(I took the screenshots from OpenStudio, I couldn’t find the Visualize By Type components in the legacy version…)

I’m not sure what happens when you don’t solve adjacencies heat transfer-wise, I don’t know how it is modeled in that case in EnergyPlus. Maybe someone could shed some light on it.

I have a suspicion that the second case is also incorrect.

I couldn’t figure out why your heating demand drops so drastically, I haven’t checked the .idf outputs to see if anything else is changed (based on your script, nothing should be).

furtonb · December 23, 2020, 9:01am

what is the “zero boundary tool”?

liuke · December 23, 2020, 2:26pm

Thank you very much for your help. I will double check what caused the third model’s heating demand to drop sharply. I guess this may be caused by the ventilation setting.

furtonb · December 23, 2020, 2:29pm

I’ve tried changing the 2nd model: I inserted the solve adjacencies component before the glazing addition, it dropped too, and I didn’t change anything else.

If you manage to figure it out, would you mind posting the solution?

liuke · December 23, 2020, 2:57pm

Although I still don’t know what the reason is, after I added a custom EnergyPlus zone load setting, the heating demand looks normal.

building energy simulation12.23.gh (960.5 KB)

Thank you again for your kind help.