Performance investigation of a novel flat-plate solar air collector with L-shaped dual micro heat pipe arrays

To improve the thermal performance of solar air collectors by reducing heat leakage and fully transporting the heat absorbed in the evaporation section, this paper proposes a structural innovation based on previous research, that is, L-shaped dual micro heat pipe arrays integrated with a flat-plate solar air collector with a double glazing cover. Experiments are conducted to investigate the thermal performance of the proposed collector. The effects of solar irradiation, ambient temperature, and air flow rate on thermal performance are reported. Thermal resistance is analyzed theoretically. The application performance of the collector is evaluated based on a typical rural building heating model. The results show that the average heat collection efficiency is 49.72 %, 55.69 %, 59.37 %, and 61.48 % for air flow rates of 80, 120, 160, and 200 m³/h, respectively. The evaporation section temperature is reduced by a maximum of 25.28 °C under flow rates of 200 m³/h. The performance of the solar collector is more significantly influenced by solar irradiance than by ambient temperature. The average thermal efficiency is linearly related to the normalized temperature difference. The CO₂ reduction over the lifetime of the device is 15040.09, 19287.80, and 5662.95 kg compared with the use of conventional bulk coal, electricity, and natural gas, respectively.