Solar load in Icepak
 

Hi all,

I was simulating an enclosure in Icepak with solar load and noticed some unlogical behaviour. Then I tested a very simple model (a rectangular plate under the sun) and noticed the following:
- no matter what values for direct and diffuse solar absorption of the surface I set the result (temperature of plate) is always the same
- there is a temperature increase even in case when I set absorption to 0 and sunshine fraction to 0, since it seems that diffusive irradiation is always assumed to be absorbed completely (even if diffuse irradiation absorption is set to 0)

It is also not clear to me how the sun's position is calculated, since only the northward direction is required as input. It seems that gravity direction also plays some role as an error is reported if northward and gravity direction are the same. (I didn't try what happens if gravity is not defined)

Does somebody know how exactly the solar load model works in Icepak and do the above results imply a bug or am I missing something?