Comprehensive energy utilization study of novel air-cooled BIPVT Modules in low-carbon buildings: A case study of a laboratory building in Tianjin

Building integrated photovoltaic thermal (BIPVT) technology combines solar photovoltaic modules with the building envelope, which can enable the modules to generate electricity and heat, providing an effective technical way to reduce building energy consumption, and it is a very promising low-carbon energy-saving technology for application. In this article, the author proposed to apply air-cooled BIPVT modules based on micro-heat pipe arrays to the building envelope. Taking a certain experimental building in Tianjin as a demonstration application object, a mathematical model of the module and an energy consumption simulation model of the experimental building were established. The surface temperature, power generation, and heat collection power of the module under different conditions were analysed. The results show that, under typical winter conditions, the total solar energy utilization efficiency is 35.7%, and the comprehensive performance efficiency is 55.28%. The maximum heat collection of the module can meet 24.81% of the fresh air heating demand. Under typical summer conditions, the presence of cooling fans significantly increases the power generation capacity of BIPVT modules, with a total increase of 6.33 W/m² of power generation on that day compared to the case without the cooling fan (natural convection). The air-cooled BIPV/T module has a significantly higher instantaneous power generation efficiency compared to conventional PVT modules, with an average daily solar power generation efficiency of 10.7%. An analysis of the energy-saving and emission reduction benefits of the BIPV/T building indicates that the annual power generation of the module is 7679.32kWh, reducing the consumption of standard coal by 5648.14kg. In the whole winter, the heat collection of the BIPVT module bears a fresh air load of 8866.48kW, which means that the modules can reduce carbon dioxide emissions by 6521.3kg compared to electric heating. Consequently, the building diminishes its CO₂ emissions by a collective 12,169.44 kg over the span of a year. The results showed that applying air-cooled BIPVT modules based on micro-heat pipe arrays to a building can not only satisfy the building's multiple energy demands, but also reduce the building's consumption of conventional energy, which has good energy-saving, environmental protection and economic benefits.