Unsteady-state performance comparison of tandem photovoltaic-thermoelectric hybrid system and conventional photovoltaic system

Abstract

This paper provides a comprehensive unsteady-state performance comparison between the tandem photovoltaic-thermoelectric (PV-TE) hybrid system and the conventional photovoltaic (PV) system. The three-dimensional unsteady-state models of the two systems are established. The effects of weather and season conditions on the superiority of coupling utilization are studied. The annual performance difference between the two systems is analyzed, and the optimal external working conditions of coupling utilization is revealed. The results demonstrate that compared with the conventional PV system, the tandem PV-TE coupling system can achieve higher electrical efficiency in any weather or season. The tandem hybrid system achieves the highest average efficiency of 27.43% in February, while that of the conventional PV system is only 26.46% in December. However, the efficiency enhancement of hybrid utilization is at the expense of reducing the system security and stability. The photovoltaic cell in the tandem hybrid system works at a higher temperature, and the change in direct solar irradiance has a more significant impact on hybrid system temperature and efficiency. When working in the cloudy day, the stability of the hybrid system will be diminished, and the superiority of hybrid utilization will be weakened. Moreover, the tandem hybrid system is proved to be more suitable for use in areas or times with high direct solar irradiance and low ambient temperature. The results can be employed to guide the application and design of the practical PV-TE hybrid system.