Performance evaluation of self-cooling concentrating photovoltaics systems using nucleate boiling heat transfer

Abstract

Abstract In this study, nucleate boiling heat transfer (NBHT) based self-cooling thermal management system is designed and thermodynamically analyzed for high concentrating photovoltaics (CPV). The overall self-cooling system, consisting of two rows of CPV i.e. CPV 1 and CPV 2, iscoupled with the absorption cooling (AbC) system. Thermal energy from CPV 1 is supplied to AbC system to produce cooling, which is then used to reduce the temperature of CPV 2. Both CPV systems work simultaneously under the same solar energy conditions, hence, the demand and supply of energy are continuously in phase. Under the designed conditions, CPV 1, with an installed capacity of 66.4 kW, an operating temperature of 375.3 K and electrical efficiency of 35.5%, has the ability to cool down about 50.6 kW of CPV 2 system with an operating temperature of 335.8 K and 37.5% of electrical efficiency. A parametric study is performed to analyze the performance of the overall system at various working conditions and installed capacities. Furthermore, the designed system is analyzed for two different types of multi-junction solar cells and three different types of coolants: water, ethanol, and n-pentane. Due to higher latent heat, water has been proven to perform better working fluid with higher ability of concentration ratio. The optimum NBHT operating temperatures for CPV1 and CPV2 were found to be about 353 K and 349 K with maximum overall system efficiency of 36.64%.