Dear Oselen,
you are right with your idea, if you set the longwave radiation mode to simple and set the combined heat transfer coefficient equal to the convective part, the
longwave radiation is effectively zeroed. One thing to keep in mind is that this is then the case for all surfaces in the room.
If you want to consider the longwave radiation for all surfaces
but the window, you can use the same method you did for the outside case. You can select
longwave radiation detailed mode for the zone and set the back emissivity of the glazing + the frame to 0, too. In this case the window will behave like a
longwave radiation-mirror so to speak and the
longwave radiation exchange will still be calculated using view factors between the other surfaces in the zone.
Best regards,
Christina
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Von: TRNSYS-users <trnsys-users-bounces@lists.onebuilding.org> im Auftrag von Oselen Imafidon via TRNSYS-users <trnsys-users@lists.onebuilding.org>
Gesendet: Freitag, 29. Oktober 2021 15:21
An: trnsys-users@lists.onebuilding.org <trnsys-users@lists.onebuilding.org>
Cc: Oselen Imafidon <josephoselen@yahoo.com>
Betreff: [TRNSYS-users] Zeroing inside and outside longwave radiation of window surfaces
Hello,
To zero the inside longwave radiation of the window I used the simple model longwave radiation exchange within a zone.
To zero outside longwave radiation of the window, I modified both the window frame emissivity to zero and the front emissivity of the first window glazing in the building input description file (BIU) to zero.
I used hand calculation to verify the simulation results using the following equations for heat fluxes to the outside and inside surface and the results were same.
. The result shows inside and outside longwave radiation of window surfaces are zeroed.
Is this the right way of zeroing
inside and outside longwave radiation of window surfaces?
Thank you.
Regards,
Oselen I
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