Analysis of the incidence angle of the beam radiation on CPC

Analytic expressions have been derived for the projected incidence angles ϑ l and ϑ t from a two-dimensional compound parabolic concentrator solar collector. For a CPC the fraction of the incident rays on the aperture at angle ϑ, which reaches the absorber, depends only on the ϑ l angle. In this paper, a mathematical expression for ϑ l and ϑ t has been calculated to determine the times at which acceptance of the sun's beam radiation begins and ceases for a CPC consisting of arbitrary orientation.