摘要

Hybrid photovoltaic and thermal (PVT) collectors with sheet-and-tube water-based flat-plate structure (simplified as STWF-PVT) are very popular because of their simple structure and ease of manufacture. Generally, their performance is closely related to their structure, especially the location arrangement of photovoltaic (PV) cells. In this work, the authors present three kinds of PVT collectors with different PV cell locations, denoted as PVT-1, PVT-2, and PVT-3, representing a conventional air-gap STWF-PVT collector whose PV cells are stuck on its solar absorber, a new air-gap STWF-PVT collector whose PV cells are fixed on the bottom of its glass cover, and a zero-air-gap STWF-PVT collector, respectively. Experiments and computational fluid dynamics (CFD) analyses were carried out to investigate the performance of these STWF-PVT collectors, by means of various comparisons with a pure thermal collector. The effects of the PVT configuration and the covering factor of the PV cells on the collector performance were discussed. Among these PVTs, the PVT-1 behaves with the greatest overall efficiency, followed by PVT-3 and PVT-2 in turn, whereas PVT-3 is proven to have the highest photoelectric conversion efficiency of PV cells, followed by PVT-2 and PVT-1. In summary, PVT-3 is much preferred by the customers who want more electricity than thermal energy, and PVT-1 is the first choice for a comprehensive evaluation of electrical and thermal energy. The authors hope this work is useful for STWF-PVT collector design, especially for the location design of PV cells and air gap.