Can Optical Shading in Solar Concentrator Be Improved with Total Internal Reflection?

Solar concentrators with multiple stages are typically favored to reduce the overall dimension of the concentrated photovoltaics (CPV) design. However, dual-stage concentrators like Cassegrain concentrators pose an issue with shading losses as the part of the concentrator obscures the aperture. This study highlights the use of the total internal reflection (TIR) phenomenon to allow some light rays to transmit through a reflector by replacing it with a TIR prism. The prism was designed by initially defining the vectors of the intended ray pathway being transmitted through and reflected off. Optimization of the TIR prism was performed with a genetic algorithm to determine the suitable pitch for the prisms and fractal iteration on the lower part of the prism. Results demonstrated a drop in optical efficiency from 62.7% with aluminum reflectors to 49.8% with TIR prism. 0.18% of the optical efficiency is transmitted by the TIR prism, which indicates indifference to aluminum reflectors. Future work has been proposed to include different prism profiles and optimization methods.