Optical design of a new combo solar concentrator

Abstract

Light concentrator is a non-imaging optics whose design can seriously affect the performance of a concentrating photovoltaic module. For effectively increasing the incoming light flux, a new combo system designed by the edge-ray theorem was proposed for solar concentration optics. This system is composed of three zones of total internal reflection (TIR) lens, Fresnel lens, and aspherical lens. In this system, the TIR lens is responsible for large bending angle, while the Fresnel lens and aspherical lens are responsible for small bending angle due to their suffering for total internal reflection at large bending angle. For the requirement of compactness, the TIR lens is located at the outmost zone from optical axis of the lens aperture to shorten the depth of the lens system. The aspherical lens is located at the central zone while the Fresnel zone is then aligned between them. On this design example, the size of solar cell is assumed to be a square with a length of 5.5 mm. The diameter of the lens aperture is 120 mm and the depth of the lens is considered to be lain between 60 and 65 mm. Through design analysis, the full acceptance angle is set at 1.0 degree. Design data shows that this new combo system can meet the requirements of solar concentration optics under considerations and its optical efficiency of the whole system can approach to 81%.