Lets say I have a coil that is 1cmx1cm in area that gets heat up. I am told that I get 2W/cm^2/sr output. So if I had 100 of them in an array, the total radiant intensity would be (2W/cm^2/sr x 100 x 1 sqcm =) 200W/sr. Now, let's say I add a parabolic reflector around each coil. How would I estimate the increase in radiance and radiant intensity (in the direction of the reflector? Do I now use the aperture area of each reflector instead of the area of the coil? Do I multiply by 2pi since now I can able to see the radiance from the back of the coil? This is where I am getting confused.