HOMER Pro 3.9
The solar absorptance of a surface is the fraction of the sun's radiation that the surface absorbs.
The solar absorptance is a factor in the calculation of the PV array temperature. But it is a relatively unimportant one, so rather than making you enter it, HOMER uses the assumption suggested by Duffie and Beckman (1991) that the product of the solar absorptance and the solar transmittance is 0.9 or 90%.
See also
