PV/T solar panel for supplying residential demands of heating/cooling and hot water with a lower environmental thermal load

The practical efficiencies of existing commercial m-Si and CIS PV modules measured in reality by our group were less than 15 % because of the higher temperatures of the PV modules, and the rest of more than about 85 % of solar energy would be the exhaust heat to the environment. It was already reported in 2020 that the principle of an environmentally-friendly PV/T (Photovoltaic/Thermal) solar panel using an m-Si PV module to utilize 71.3 % solar energy for electricity and 40 °C hot water, as well as suppress heat radiation from the panel. The panel was designed to confirm the principle, i.e., it was an experimental PV/T solar panel. In this paper, a new practical environmentally-friendly PV/T solar panel is proposed for aiming the application to BIPVT (Building-integrated Photovoltaic/Thermal) systems. The new panel uses a CIS PV module, and all the functions, including a heat exchanger using flat aluminum tubes, are placed in the panel box, which is almost the same size as a simple CIS PV panel. The proposed PV/T solar panel converts 73.5 % of solar energy with 13.0 % power generation efficiency and 60.5 % heat collection efficiency at a 40 °C hot water supply in Yokohama, Japan. The efficiency is higher than the previous experimental panel. The proposed panel also can suppress heat radiation at about 50 °C even in the case of 60 °C hot water supply. The proposed PV/T solar panel can supply all residential heat demands, such as domestic hot water (DHW) and space heating or cooling, using solar heat with a lower environmental thermal load.