Electro‐optical study of a ×1024 concentrator photovoltaic system

Abstract

Concentrator photovoltaic (CPV) systems are one of the most promising technologies for future energy supply. Several studies reported the interest of using a Fresnel lens coupled with a secondary optical element in such a system. For high concentration factor, the optimization of the optical configuration plays a key role regarding electrical performances. On the other hand, the thermal management of the solar cell is also critical to ensure a better module efficiency. This paper presents a study of a Â1024 CPV system performances and a methodology for estimating the optical chain efficiency, the cell temperature impact and the alignment requirements. Module efficiencies were then measured as a function of the cell temperature and correlated to optical performances through current-tension characterizations under real solar illumination conditions and the estimation of the power density received by the solar cell. The system yield was up to 27% for a cell temperature around 30 C, confirming that high concentration ratio should be of great interest in the near future. A 1D model was also developed in order to quantify the possible improvements of this CPV system. Using a solar cell with an efficiency of 36.7% at Â600, we then demonstrated that the Â1024 CPV system could reach up to 30% in standard test conditions.

Challenges in the design of concentrator photovoltaic (CPV) modules to achieve highest efficiencies

“…The color code is as follows: blue, systems including silicon solar cells and Fresnel lenses (all the others are based on multi-junction solar cells); red, systems based on Fresnel lenses as primary optics; green, systems using reflective primary optics; pink, micro-CPV system based on refractive primary optics; and orange, two stage optics with primary stage working by total internal reflection (TIR). 20,[25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41] The continuous lines represent the theoretical limit of the attainable concentration acceptance angle product (CAP) achievable according to the conservation of etendue, for a system where the cell is surrounded by air (n out ¼ 1) or a medium whose refractive index is n out ¼ 1.5, i.e., glass or silicone. (a) As for the early systems, measured acceptance angle has not been reported, and a value for the CAP equal to the most similar technology (Amonix) was assumed.…”