Optical, electrical, and thermal performance of low-concentrating photovoltaic/thermal system using microencapsulated phase change material suspension as a coolant

Concentrated photovoltaic/thermal (C-PV/T) systems exhibit superior output compared to common PV/T collectors. To address potential issues caused by excessive concentration of conventional parabolic concentrators and enhance the electro-thermal co-generation capability, this work proposes a low-concentrating PV/T (LC-PV/ T) system that integrates two improved concentrator designs and a coolant of microencapsulated phase change material suspension (MPCMS). A numerical model is established to investigate the effects of working conditions and meteorological conditions on the optical, electrical and thermal performances. The results indicate that the improved concentrator designs effectively prevent over-concentration of sunlight while maintaining a comparable concentration ratio (CR). The electrical output increases with an increase in mass fraction, inlet mass flow rate and solar irradiance, but decreases with an increase in ambient temperature and inlet temperature. Conversely, thermal output increases with an increase in all of these parameters except for the inlet temperature. This system can achieve 17 % electrical efficiency and 72 % thermal efficiency due to the high-efficiency solar cells, optimized concentrator design, and unique MPCMS coolant. The system can produce a maximum electrical power of 4.76 kW/m2 and a maximum thermal power of 19.53 kW/m2. Throughout the day, total electrical and thermal energies are approximately 4.1 kWh and 58.8 MJ.