ANALYTIC SOLUTIONS FOR THE OPTICAL AND RADIATIVE PROPERTIES OF NONACCEPTED LIGHT RADIATION OF V-TROUGH CONCENTRATORS

Knowledge of optical and radiative properties is often essential for t he design and evaluation of V-trough solar energy collectors. Using th e concept of reflection modes, we derived a set of functions associate d with each mode; this allowed us to calculate the optical and radiati ve properties for rejected light radiation. These expressions, togethe r with those for accepted light radiation published previously, were u sed to calculate the optical efficiency for beam radiation and the exc hange factors (diffuse radiation) between aperture and absorber (accep ted light) and between aperture and aperture (rejected light). Numeric al results of these factors were obtained for various combinations of concentration ratio and vertex angle. Results are compared between a c ase in which the reflectivity is constant and one in which the reflect ivity varies with incidence angle; the difference does not exceed 1% f or a reflectivity of 0.8. Considering the reflectivity as a constant a llows us to obtain analytic solutions for the exchange factors, expres sed as a sum of trigonometric functions.