Whole window SHGC calculations

[vidanovic]

WINDOW 7.8.14

When calculating whole window shgc, WINDOW uses frame exterior convective film coefficient to estimate SHGC for the frames. Problem is that current algorithm is including radiative part as well.

In example I was testing h_cout should be 15 (according to the NFRC conditions), while window passes number that is sum.
Here is the part of the debug output file:

hcout =  15.000000   hrout =   5.591552   hout =  20.591552

This caused small differences in SHGC for the entire WINDOW.
Using 20.59 SHGC is calculated to be 0.3716 while using 15.00 SHGC is calculated to be 0.3732.