Performance investigation of multi-functional series-connected building-integrated photovoltaic/thermal system and analysis of its multi-objective optimization design strategy

The series-connected building-integrated photovoltaic/thermal (BIPVT) system can significantly increase the terminal temperature and achieve both power generation and heating. However, its utilization of thermal energy is limited. Airborne infectious diseases threaten indoor occupant health. Pathogenic microorganisms can be thermally inactivated, and the effectiveness of inactivation is positively correlated with exposure temperature and duration. Therefore, series-connected BIPVT system has the potential for air thermal disinfection. Based on this, a multifunctional series-connected BIPVT system that provides heating, power generation, and air purification is proposed. However, these three outputs conflict with each other, and there is a lack of optimized design strategies to maximize the system's overall output. In response, this paper develops a multi-objective optimization strategy for the system and optimizes its design across different climate zones. The main content is as follows: (1) Compared with single-stage systems, series systems can significantly improve air purification performance. The series-connected BIPVT system with the best air purification effect can increase the single-pass inactivation ratio to 100 % under the irradiance of 600 W/m² (2) The glazed photovoltaic/thermal-glazed solar thermal system has the best thermal performance and air purification performance, the thermal efficiency is 38.1 % and the clean air delivery rate is 98.6 m³/h under the irradiance of 800 W/m² (3) Compared to single-objective optimization and non-optimized designs, the multi-objective optimization design achieves the highest technique for order of preference similarity to the ideal solution (TOPSIS) score, which is 0.5968.