Design optimization of fixed V-trough concentrators

In this work, a mathematical procedure to predict collectible radiation on the base of a V-trough concentrator, to which solar cells are attached, was developed based on the imaging principle of planar mirrors, solar geometry and monthly horizontal radiation. Calculation results showed that radiation annually received by the base of a fixed east-west aligned V-trough with given geometric concentration ratio (C_g) depends on its opening angle, reflectivity of reflectors, tilt-angle and climatic conditions in site. Thus, for design optimization, determining C_g based on practical requirements first, and then an optimal opening angle and corresponding optimal tilt-angle for maximizing its annual energy collection could be obtained based on reflectivity of considered reflectors and climatic conditions in site. For a V-trough with high reflectivity of reflectors, the opening angle should be small so as to reduce the incidence angle of solar beam on the base, whereas for a V-trough with low reflectivity, a large opening angle should be selected to allow more beam radiation directly incidence on the base. Results also indicated that such concentrator is preferable to use in the areas with abundant solar resource, and an annual average optical concentration ratio larger than 1.4 could be reached.