Optical Performance of Low Concentration Ratio Reflective and Refractive Concentrators for Photovoltaic Applications

Abstract Solar concentrators have the potential to replace the expensive PV cells with cheaper optical elements without affecting the overall output of the solar panel. Small scale concentrators with low concentration ratios offer the advantage of light weight, small size and easy to install without the need of tracking. Such concentrators use either reflective or refractive optical devices to focus the solar light onto a photovoltaic surface and increase its power output. Using advanced ray tracing techniques, this work investigates the optical performance of low concentration ratio reflective and refractive concentrators. Three different geometries of reflective concentrators and two geometries of refractive concentrators were investigated under the same range of concentration ratios. Results showed that both types of concentrators have similar optical efficiency for concentration ratios up to 10. For concentration ratios above 10, the performance of reflective concentrators has deteriorated significantly while the refractive concentrators have retained their high optical efficiency highlighting the potential of refractive concentrators.