Effect of diffuse blinds on design cooling loads

Pollen · Posts: 2

Hello,

I got some strange results with (slightly) higher cooling loads with some internal diffuse blinds compared with no blind at all. Did somebody experienced already this situation and can give a technical explaination ?
Note that the results are "correct" (loads lower with blinds) when the reflectance is high and the transmittance is low (E+ source).
Thank you for your help.

Best regards

Benoît Cogné
DH TECHNOLOGIES
France

Andy Tindale · Posts: 1198 Location: Stroud

One reason why diffusing blinds might increase cooling loads is that they tend to cause solar radiative gain to be converted to a convective gain. This can cause higher air temperatures than would occur if the solar radiation gain is absorbed into the floor and walls and other building thermal mass. The higher convective gain will lead to higher cooling loads in cases where the control radiant fraction is zero (the DesignBuilder default).

Andy

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