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OpenStudio Shading Surface Reflectance

asked 2021-05-12 13:51:49 -0500

I have two models, both with the same shading surface covering the roof. One model has thermal absorptance at 0.1 (0.9 reflectance), the other model has thermal absorptance at 0.9 (0.1 reflectance). All other parameters are the same. I am simulating using FullInteriorAndExteriorWithRefections.

Why would the Roof Surface Heat Gain be more with a highly reflective shading surface? It must be reflecting building heat back more than the other one is allowing solar radiation through?

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answered 2021-05-15 04:48:23 -0500

updated 2021-05-15 04:49:28 -0500

It seems there is a space below the roof and probably some insulation exists between the roof and the conditioned spaces probably due to that the effect of high/low reflectance is neglectable at whole building level. Try to report energy demand at spaces level and take a look what happens on the top level spaces.

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Asked: 2021-05-12 13:51:49 -0500

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Last updated: May 15