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Nighttime sky temperature radiation
Posted 23 nov 2021, 10:47 GMT-5 Heat Transfer Version 5.6 0 Replies
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Hi,
I am working on a 3D model of a wall with the Heat Transfer in Solids and Surface to Surface Radiation, using the results obtained for a comparison with other data I have. During daytime the results are consistent and very similar, however during nighttime the wall in COMSOL is hotter than it should be. After some considerations, I came to the conclusion that this different is due to the radiation with the sky that wasn't considered. Has anybody dealt with the nighttime radiation with sky? If yes, how? I wasn't lucky enough to find something in literature. I only found a tutorial example about the radiative cooling, but unfortunately that doesn't fit to my problem.
Considering that in the Diffuse Surface in the Surface to Surface Radiation only one temperature is required, at first I gave the air temperature and included the radiation with the sky in the convective heat transfer coefficient (calculating a sort of equivalent h - this gave good results).
I am now trying to set a different reference temperature in the Diffuse Surface (something like a weighted average between the air and the sky temperature), however with no results so far. Has anyone already worked with something like this or could give me some advice?
Many thanks! :)
Hello Eleonora Baccega
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