How to calculate the mean radiant temperature/angle factor?

[wufi2004]

From Ashrae handbook chapter8, I can find angle factor from the figure, then I can use F1*T1+F2*T2+... to get the mean radiant temperature. How can I get the angle factor/view factor from Equations(not from a chart)? I need the equation to get angle factor and write a code.

 

[davefitz]

not familiar with the ashrea charts, but the most effectivemeans of determining a radiation view angle is to use "Hottel's crossed string method" - refer to any standard radiation text written since 1920.