Improved Radiation Uniformity in Concentrating Photovoltaic System using Reflective Secondary Optic

Abstract This paper presents the adjustment of the optical setup in conventional concentrating photovoltaic system (CPV) to improve the radiation uniformity. The experiments were carried out by using commercial CPV components including Fresnel lens with the diameter and focal length of 14cm and 19cm, respectively, and 6x6 mm InGaAs/ InGaP/Ge PV cell. The secondary reflective optic element (SOE) was placed on the top of each PV cells. The parameters of reflective secondary optics were estimated from ray tracing method. Four PV cells were placed at different distance from Fresnel lens to adjust the pattern of sun beam that exposed on the cells. The approximated beam diameter was also calculated. The results show that the Fill factor of the CPV system can be improved by 5-15% depending on position of PV cell and solar radiation condition. The system with SOE can keep the loss of optical efficiency to less than 5-15%. The maximum power output of the CPV system with SOE of can be further increased up to 10%.