Feasibility analysis of a tandem photovoltaic-thermoelectric hybrid system under solar concentration

This paper aims to provide a comprehensive feasibility analysis of the tandem concentration photovoltaic-thermoelectric (CPV-TE) hybrid system to guide practical hybrid system design. Theoretical models and experimental equipment of the concentration photovoltaic (CPV) system and the CPV-TE hybrid system are both established. The working temperature and output power of the two systems at different solar concentration ratios are first measured and compared. Then, the effects of different device performance and system operating parameters, including PV reference efficiency, PV temperature coefficient, TE figure of merit, concentration ratio, thermal contact resistance, cooling performance, coolant temperature, and TE thermal resistance, on the feasibility of coupling utilization are theoretically investigated. Finally, some design principles of the tandem hybrid system are provided based on the research results. The experimental results demonstrate the superiority of hybrid utilization when using a single-junction gallium arsenide PV cell, and a maximum output power improvement of 8.7% (from 1.38W to 1.5W) can be achieved when the concentration ratio is 255. The theoretical results illustrate that device performance parameters are the main factors that determine the feasibility of hybrid utilization. Choosing appropriate system operating parameters is also important to ensure the superiority of the hybrid system.