Reliability and temperature limits of the focal spot of a primary optical component for an ultra-high concentrated photovoltaic system

Concentrated photovoltaics (CPV) are competent systems for generating electrical power as they depend on a highly efficient semiconducting material. In this paper, we study the indoor thermal and electrical performances of silicon on glass Fresnel lens as an initial investigation step for an ultra-high concentrator photovoltaic (UHCPV) system [1]. This investigation includes the maximum temperature at the focal point as well as of a multi-junction solar cell after concentrating the solar irradiance using the primary optical component. These maximum temperature results will determine the input maximum working temperatures for the secondary and tertiary optics in the UHCPV design. The temperature profiles expected for the receiving cells or secondary optical materials are described, including the effects of tabbed metal connections within the focal spot. In addition, a comparison between the two methods (thermocouples and Infrared thermal camera) for measuring the temperature distribution is presented. A maximum difference of 1.81% between the two methods has been reported. The electrical performance of the system has been studied under different scenarios. This includes the effect of cooling temperature, solar irradiance, and the possible misalignment between the Fresnel lens and the receiver. Maximum temperature and power output of 100 °C and 2.5 W for the solar cell have been detected at effective solar irradiance of 77 kW/m2.