Weird zone mean air temperature in Case 600 FF of the Building Energy Simulation Test in energyplus
In recent times, I want to run some standard cases in <<energyplus testing="" with="" building="" thermal="" envelope="" and="" fabric="" load="" tests="" from="" ansi="" ashrae="" standard="" 140-2011="">>. 140-2007="">>. These cases are used for comparison of heating and cooling load provided by different softwares.softwares. You can download the PDF file from this website.
http://www.labeee.ufsc.br/sites/default/files/disciplinas/ECV4202_EnergyPlus%20testing%20with%20Ashrae140.pdf
I downloaded Case 600FF and Case 900FF from this website
https://github.com/NREL/BESTEST-GSR
This website says its purpose is to generate BESTEST (Building Energy Simulation) test case models, run simulations, and populate data for ASHRAE Standard 140 reporting spreadsheets for EnergyPlus based whole building simulation tools. So I just used the default idf file the website provided.
Here is the weird thing to me. I didn't change any setting. But the simulation result shows the zone mean air temperature in Case 600FF even increases to 60℃ in winter during the datetime. daytime. It seems unreal. Could anyone tell me some possible reasons? Now I think the idf file from the website is valid. Here is the result.
The red line shows the temperature of Case900FF, and the blue line is the temperature of Case600FF.
C:\fakepath\airtem Case600FF Case900FF.png
I have something to explain about these two cases. Their setting is similar except for the thing that Case 600FF is of lightweight construction but Case 900FF is of heavyweight construction. Especially, they have no HVAC equipment for mechanical heating and cooling. Here is the geometry of the building used in both two cases.
PS: I calculated natural room air temperature and found in the daytime the air temperature could indeed increase to 40 ~50℃ due to the cases.
C:\fakepath\Case 600FF.png
I have a guess. Is it the big windows facing south of a large area. Maybe this is the reason?area that cause weird results? Because during the daytime, there is abundant solar radiation. In addition, the building in Case 600FF consists of lightweight walls, floor and has no HVAC equipment. When solar radiation is abundant, the indoor air temperature may increase to 40~50℃. Is it correct?