Experimental study on the operating characteristics of a novel photovoltaic/thermal integrated dual-source heat pump water heating system

This paper proposed a novel solar photovoltaic/thermal (PV/T) integrated dual-source heat pump (DSHP) water heating system. This system used the circulating water in solar photovoltaic thermal system and air source to provide domestic hot water for domestic usage, and meanwhile decreased the cooling water temperature for the PV/T panel to improve the electrical conversion efficiency. An experimental PV/T integrated DSHP unit was established in Shanghai to examine its performance. The influences of the inlet temperature of the evaporator and the hot water temperature under water-water mode and the influence of the outdoor temperature under air-water mode on the system performance were studied. Energy analysis was conducted between water-water mode and air-water mode. The cooling effect and photovoltaic efficiency of the PV/T panel were evaluated. The results showed that when water side evaporator was used, the PV/T panel operating temperature can be decreased up to 45 °C, and the electrical conversion efficiency yielded a surplus of 10.3%.