How can I set Solar Absorptance for windows?
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I am employing a CFD software to study site-specific weather boundary conditions. It takes into account incoming solar radiation as well as convection heat exchanges, providing surface temperatures through a global energy balance. I can, therefore, use EnergyPlus actuators on each wall to override the surface temperature.
The surface temperature provided by the CFD software already takes into account the radiative heat exchange with the sun, so I can't include it twice. I have to exclude the solar heat gain impact on my building model, modifying the building material properties. I can't just set the incoming radiation to 0 otherwise I would deny the "light gains" and the "heat gains" that come with the light filtered through the window glass.
I am setting the Solar Absorptance on the walls equal to 0 and I get the result I want. However, how can I set the same for a window? Basically, what I am trying to do is to exclude the radiant heat gain from the surface heat balances. I would like to exclude the solar heat gain on windows surfaces, without excluding the light solar contribution. Is there any way to do that, besides the Solar Absorptance coefficient?
Are you trying to exclude the solar heat gain on just the window surfaces, but still keep the solar heat gains to a zone? Could you just pass all the solar gain to the zone? Understanding your use case in a bit more detail may help determine an approach.
I am trying to exclude the solar heat gain on the whole zone. On walls, setting solar absorptance to 0 works fine enough. However I am trying to figure out what to set on the windows. Maybe the solar heat gain coefficient? I can't just set the incoming radiation to 0 otherwise I would deny the "light gains" and the "heat gains" that come with the light filtered through the window glass.
Visible light is part of solar heat gain. Some of your heat gains include your light gains.
Could you explain your use case and the problem you are considering? That will help those on the forum better recommend a modeling approach.
Yes, sorry, I modified the question and I added more details.
What I am talking about is basically the effect of visible light that filter through a transparent surface. Like in a greenhouse: The incoming solar radiation affects the heat balance on the greenhouse external surface, but the visible radiation filters through and heats up the greenhouse. I would like to include in my model this second effect, getting rid of the first one (surface heat balance). Any idea how to do that?