Discussion Forum

Hello,

I am trying to model 3D composite wall/window with all 3 types of heat transfers.

The geometry model is very simple. It consists of cube with 3 layers. Outer and inner layers are made of glass and the middle layer is filled with air. One side of the geometry is exposed to atmosphere. The irradiation value on this outside wall is 720 W/m^2. The outside temperature is 32degC. The transfer coefficient(h_ce) between outside wall and outside atmosphere is 4 W/m^2K. Conduction is observed through different layers. Temperature on the inner side of wall is 26 degC. The transfer coefficient(h_ce) between inside wall and room atmosphere is 3.6 W/m^2K. All other 4 sides are thermally insulated. There is some amount of radiation transmitted(τ = 0.9.) from outer panel. So the inner panel recieves radiation from outer panel and in turn radiates further into the room.

Following are settings in radiation node: I am using surface-to-surface radiation with outside wall exposed to outside atmosphere as diffuse surface. Opacity - Infinite void External radiation source - Solar irradiance is taken from ambient as "Clear sky noon beam normal irradiance"

I do not understand how to model the radiation that is incident on second panel from first panel. Can you help me with that?

I expect the result as shown in the attached image. This is taken from analytical calculations from respective norms.

Thanks in advance.

Saketh