Thermal-electric performance analysis of a novel solar-air hybrid microchannel PV/T heat pump system for alpine and high-altitude regions

Residents of alpine and high-altitude regions endure extreme cold coupled with frequent electricity supply scarcity. To address this problem, a novel solar-air hybrid microchannel photovoltaic/thermal heat pump system (NMC-PV/THP) is proposed, which integrated the microchannel collector evaporator with ribs and fans, enhancing electrical efficiency while providing thermal energy. Experiments were conducted to compare the thermal-electric performance with the traditional PV, air source heat pump (ASHP) and the traditional microchannel PV/THP without ribs and fans (TMC-PV/THP), and a mathematical model was constructed to analyze the influence of structural/operation parameters and the geographical adaptability. The results showed that the proposed system had obvious advantages, with a relative improvement of 11.4% in electrical efficiency compared to the traditional PV panels. Furthermore, the average COP increased by 11.4% and 77.3% compared to the ASHP and the TMC-PV/THP, respectively, and 3.1%-37.0% compared to the existing PV/THP. The parallel operation of dual NMC-PV/T evaporators boosts total electricity generation, but it comes at the cost of additional thermal loss. A solar irradiance escalation from 100 to 1000 W/m2 results in 3.9 °C rise in evaporating temperature, while it rises 15.6 °C for the ambient temperature increases 20 °C. The system effectively balances heat collection and power consumption when the air velocity is 3 m/s. The significant benefits of applying in the solar energy-rich regions represented by Lhasa were revealed, with an average COP of 2.6, an overall efficiency of about 62.3%, and a cumulative power generation of 5.32 kWh per day. Overall, the results from this work represent broad application perspectives and energy-saving benefits.