Analytical determination of the optical performance of practical parabolic trough collectors from design data

Abstract A semifinite analytical formulation is presented to facilitate the efficient numerical computation of the concentrated radiant flux on receiver surfaces in the parabolic trough concentrator. The concentrated flux density is integrated to yield the interceptance ratio for the collector. By including models for the incident-angle dependent envelope transmittance and receiver absorptance, the concentration ratio for absorbed radiation is also calculated and integrated to yield the optical efficiency. Flux distribution results from this detailed analysis are compared with a point source model, and the optical efficiency results are compared with a first-order model. Since this model includes both a realistic nonuniform solar modeling as well as models for imperfect reflection, transmission, and absorption, it is capable of estimating the optical efficiency of practical collectors.