Solar Hybrid System Component Study in Low Concentrated Sunlight

Abstract

The solar energy is increasingly used as a renewable energy source. Raising the efficiency of energy conversion from solar to useful energy (electric and thermal) represents an important research direction in the renewable energy domain. Using hybrid systems for electric and thermal energy cogeneration can be a solution. In this study, a hybrid system (HS) is designed, manufactured, implemented, and experimentally tested under concentrated sunlight with a concentration ratio of 25 suns, obtained using a Fresnel lens as a sunlight concentrator. The HS comprises of four concentrated photovoltaic cells (CPVs), four thermoelectric generators (TEGs), and a solar thermal collector (STC). The HS is studied in three configurations of the exposed surface: only the CPV active area, the CPV active area with ceramic support, and the CPV active area with ceramic support covered with graphite sheet. Results reveal that the efficiency of each system component is affected by the exposed surface. If the efficiencies of the CPVs decrease from 32.3% to 30.8% from the first configuration to the last one, the efficiencies of TEGs and STC increase from 0.12% to 0.44 and from 26.3% to 52.0%, respectively. Increasing the concentration ratio from 25 to 33 suns, the power of the CPVs increases with almost 31%, but the efficiency decreases slightly, instead the efficiencies of the TEGs and STC increase.