Ultra-low heat loss photovoltaic/thermal collectors based on vacuum and low emissivity technology

Existing photovoltaic/thermal(PV/T) collectors suffer from issues such as significant heat loss, low thermal efficiency, and the inability to generate sufficient thermal energy in winter. In this paper, a novel ultra-low heat loss PV/T collector is developed by integrating vacuum insulation with low-emissivity technology, effectively suppressing heat dissipation and enhancing thermal efficiency. Through structural optimization of the solar cells and stress analysis of the vacuum chamber, the ultra-low heat loss PV/T with engineering application dimensions has been successfully constructed. A comparative experimental platform is established for the novel PV/T and the conventional PV/T, and systematic experiments have been performed to evaluate the performance advantages of the novel PV/T under varying inlet water temperatures and seasonal conditions. Experimental results show that the normalized heat loss coefficient of the ultra-low heat loss PV/T is 3.43W/(m2⋅K), which represents a 35.44 % reduction compared to conventional PV/T. The thermal performance advantage of the novel PV/T system becomes more pronounced as the inlet water temperature increases. During cold winter, with an average solar irradiance of 382∼520W/m2, the novel PV/T system can generate hot water exceeding 60 °C. This study offers significant support for the broader adoption of the PV/T system in industrial applications.