Comparison Study of the Working Performance and Thermal Stress of Different Types of Photovoltaic and Thermal Solar Collectors

Abstract

In recent several decades, the study of the cooling methods for the photovoltaic/thermal (PV/T) system has stimulated the interest of many researchers due to the electrical efficiency improvement. However, the PV thermal stress and operation reliability of PV/T systems are rarely investigated. In this work, the operational performance and the PV thermal stress induced mechanism of three types of PV/T systems: tube-sheet PV/T (TS-PV/T), heat pipe PV/T (HP-PV/T), and phase change material PV/T (PCM-PV/T) are investigated. The results show that the primary reason for the development of the PV thermal stress is the different thermal expansion characteristics between PV and absorber. Thermal inhomogeneity plays a minor role in PV thermal stress. PV thermal stress can be significantly reduced by reducing pipe spacing, absorb thickness, or solar panel coverage rate. The PV thermal stress of the HP-PV/T system is 50 MPa higher than the TS-PV/T system. The PV thermal stress of the PCM-PV/T system is 20 MPa lower than the TS-PV/T collector system.