Investigation on the heating performance of a BIPV/T façade coupled with direct-expansion heat pump system in severe cold region

Building-integrated photovoltaic/thermal (BIPV/T) technology can potentially provide considerable thermal and electricity energy for buildings use. Whereas in most cases, the thermal energy directly obtained from the system is of low grade, and its heating performance in extreme weather receives less attentions. To achieve the efficient utilization of thermal energy, this paper proposes a BIPV/T façade coupled with direct-expansion heat pump system and investigates its heating performance in severe cold regions. Full-size control variable experiments were conducted in Harbin to explore its actual performance. Based on the experimental data, a mathematical model was developed and validated, which can estimate its heating performance during the whole space-heating season. During the test, the existence of BIPV/T façade leaded to a maximum coefficient of performance of 2.8, an increase of 66.1 %. Besides, the experimental data also revealed the positive correlation between fluid supply temperature and its heating performance. When the fluid supply temperature set as 50 °C, 1 m2 of the façade can provide at least 253.3 kWh of thermal energy per month, meeting the domestic hot water demand of 389 m2 of the building area. The findings can provide some useful clues for the efficient utilization of BIPV/T technology in severe cold regions.