A focus-shifted asymmetric compound parabolic concentrator and its application in concentrating bifacial photovoltaic system

Abstract

To improve the optical performance of typical non-tracking asymmetric concentrator —Maximum Reflector Collector (MaReCo), this study proposed a novel focus-shifted asymmetric compound parabolic concentrator (FSACPC). The optical performance of FSACPCs with different geometric concentration ratios was investigated first. Then to further verify the potential of FSACPC for application in concentrating bifacial photovoltaic (CBPV) system, optical-thermal-electrical coupling models for FSACPC-CBPV and MaReCo-CBPV systems were established to study the variations of thermal and electrical performances with the light incident angle θ_in. Finally, the electrical performance and technical economy of FSACPC-CBPV system were compared with those of monofacial photovoltaic (MPV) system with the same solar receiving area under real irradiance conditions. The results show that, compared with MaReCo, FSACPC achieves a larger maximum light acceptance angle and demonstrates higher irradiance distribution uniformity in non-shadow states. FSACPC's maximum irradiance at the critical incident angle θ_cr decreases by at least 38.80 %, and the average solar radiant energy per unit concentrator area reaches a relative improvement rate of 8.29 %. Moreover, FSACPC-CBPV system has a 32.37 % lower maximum temperature of crystalline silicon cell (SC) layer at θ_cr than MaReCo-CBPV system, and exhibits larger temperature distribution uniformity. Within the same light acceptance range, while FSACPC-CBPV system having higher comprehensive electrical efficiency, its average total electrical power is also 13.06 % higher than that of MaReCo-CBPV system. Under the irradiance conditions of four typical days, the total electrical power per unit cost of FSACPC-CBPV system can be increased by at least 26.84 % compared with MPV system (at noon on the summer solstice). The levelized cost of energy (LCOE) of FSACPC-CBPV system with 1.7 of geometric concentration ratio is 0.196 CNY/kWh.