A novel TIR-R concentration module of uniformly solar energy for HCPV systems

In this paper, uniformly solar energy total internal reflection-refraction (TIR-R) concentration (U-TIR-R-C) lenses were designed using the energy configuration method to eliminate hot spots on the surface of solar cell and increase conversion efficiency. The design of most current solar concentrators emphasizes the high-power concentration of solar energy, however neglects the conversion inefficiency resulting from hot spots generated by uneven distributions of solar energy concentrated on solar cells. The energy configuration method proposed in this study employs the concept of ray tracing to uniformly distribute solar energy to solar cells through a U-TIR-R-C lens. The U-TIR-R-C lens adopted in this study possessed a 76-mm diameter, a 41-mm thickness, optical power of 1134, 82.6% optical efficiency, and 94.7% uniformity. The experiments demonstrated that the U-TIR-R-C lens reduced the core temperature of the solar cell from 108 °C to 69 °C and the overall temperature difference from 45 °C to 10 °C, and effectively increased the conversion efficiency by approximately 3.8%. Therefore, the U-TIR-R-C lens designed can effectively concentrate a large area of sunlight onto a small solar cell, and the concentrated solar energy can be evenly distributed in the solar cell to achieve uniform irradiance and effectively eliminate hot spots.