Numerical study on optical and electric-thermal performance for solar concentrating PV/T air system

Hybrid photovoltaic/thermal (PV/T) system with solar concentrator is an effective way to improve solar energy conversion efficiency. In this work, a single-pass PV/T air system with a three-trough compound parabolic concentrator (CPC) of concentration ratio 2.0 is designed and the solar incident distributions at the solar cell surface are calculated by ray tracing method. Based on energy balance, the heat transfer models of all main components in this system are developed. The effects of some main designing and operational parameters on the electric-thermal performance of the system are analyzed. The results show that the solar radiation intensity can be higher than 1200 W/m2 at most area of the cell surface. The temperature of the air and cell surface increases along the length of the system. Thus the system efficiency of the CPC is higher than that of the system without the CPC. The thermal efficiency, exergy and electrical efficiency of this CPC system increase with increasing of the air mass flow rate and the length of the system. With increasing packing fraction the electrical efficiency increases, but the thermal efficiency decreases. The exergy efficiency increases slightly with the packing fraction rising. The data obtained in this work are valuable for the design and operation for this kind of solar concentrating PV/T systems.

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