Volume 3: Innovative Solutions for Energy Transitions: Part II

Thermal Modelling of Multi-Junction Solar Cells Assembly under Fresnel-Based Concentrator Photovoltaic/Thermal System Yassir Alamri, S. Mahmoud, R. AL-Dadah

Abstract

High solar irradiance concentration on multi-junction (MJ) solar cells leads to extremely high cell temperature, which significantly reduces cell efficiency and can lead to cell damage. Therefore, heat dissipation via cooling techniques is essential for photovoltaic solar cells under high concentration. This work develops a 3D thermal model for an assembly of four MJ solar cells with a Fresnel-based HCPV/T system and investigates the capability of active cooling to maintain a maximum solar cell surface temperature under the operating limit (i.e. 80°C). Solar cells temperatures are predicted for different concentration ratios (CRs) and inlet water velocities, varying between 200X–1000X and 0.01–0.4 m/s, respectively. At a CR of 1000X and a water velocity of 0.3 m/s, a maximum cell temperature of 79.2°C can be achieved, which is below the maximum operating temperature. Furthermore, the outlet water average temperature for multiple concentrator photovoltaic (CPV) assemblies were performed. The results showed that the solar cells’ temperatures decreased with increased inlet water velocity, and sufficient temperature uniformity was achieved by active water cooling. In addition, the outlet water’s average temperature increased considerably with the number of CPV assemblies. It was found that with four CPV assemblies using a moderate inlet water velocity of 0.01 m/s, the average outlet water temperature rose from input temperature i.e. 25°C to 44°C and 62°C for a CR of 300X and 600X, respectively.

Keywords Concentrating photovoltaic, concentration ratio, multi-junction solar cells, active cooling, thermal modelling, Fresnel lens.