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architecture-building-systems / CityEnergyAnalyst

The City Energy Analyst (CEA)
https://www.cityenergyanalyst.com/
MIT License
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Bug? very high indoor temperatures #3600

Closed anjaWill closed 3 weeks ago

anjaWill commented 1 month ago

Describe the bug despite the 2015 weather file (data are fine) and a Northern Germany location, the indoor building temperatures are very high (above 100°C in Jan 1st, 1:00 am)

To Reproduce After wondering why there was no space heating demand in the project, I created a project containing solely the main building. Same result: no space heating due to extremely high indoor temperatures. German database, gas heating, window ventilation, multi-res with advanced refurbishment, no cooling. construction created by archetype mapper.

Expected behaviour space heating demand and T_int between 10-15 °C in January

Screenshots grafik

ShiZhongming commented 4 weeks ago

Hi @anjaWill Which Construction Standard did you use for the main building you mentioned?

ShiZhongming commented 4 weeks ago

Can you also share this scenario's inputs folder with me via email?

ShiZhongming commented 3 weeks ago

Hi @anjaWill

Probably it is too late that I just figured out the problem here. It seems that the weather file you are using has the sky temperaure_C in the range of 700+ while usually it should be ranging roughly between -20 to 40.. I have included a screenshot of your weather file here for your reference.

Screenshot 2024-06-11 at 23 17 02

Issue #3603 is also caused by this issue...

Maybe you want to use another weather file..

Regards, Zhongming

anjaWill commented 3 weeks ago

Hi @ShiZhongming thanks for identifying the error. I used the official weather file by DWD - German Weather Database. Might this be caused by a "translation" error: German comma vs. english points?

ShiZhongming commented 3 weeks ago

Hi @anjaWill,

We took a closer look. It is CEA calculating this sky temperature C.

Currently, CEA uses this parameter called opaqskycvr_tenths (i.e. opaque sky cover, in tenths.) from your weather file to calculate sky temperature C. However, opaqskycvr_tenths is missing in your weather file. When it is missing, it reverts 99, while actually N is supposed to be between 0-10. Hence, it casued the super high temeprature in your simulation.

@reyery and I are updating CEA to handle epw data from weather files like yours which does not have opaqskycvr_tenths. This improvement will be reflected in the upcoming CEA release. No action is required from your end.

Thank you for spotting this.

Regards, Zhongming