研究目的

To analyze the thermal performance of bifacial photovoltaic (PV) modules under different installation conditions and to quantify the effects of ground reflectivity, ground temperature, and module material characteristics on the operating temperature of bifacial PV modules.

研究成果

The operating temperature of bifacial module and the influence factors including module encapsulation material, the ground reflectivity and ground temperature are evaluated experimentally and theoretically. The simulation results with energy balance modeling show a good agreement with the measured ones. The operating temperature of the bifacial PV module is 1.89 (cid:1)C lower than that of the monofacial PV module if there is no reflection from ground to the backside of module. That is due to more transmissions of infrared irradiation from bifacial solar cells, which result in less internal heat absorption. Until the ground reflectivity reaches 26.9%, the temperature of the bifacial PV module is equivalent to that of the monofacial module. When the ground temperature changes from 10 (cid:1)C to 60 (cid:1)C, the radiation heat transfer from module backside to ground decreases by 218.5W/m2, which contribute to the bifacial module temperature increasing of 8.0 (cid:1)C.The thinner the encapsulation glass leads to the smaller the thermal resistance and the lower the cell temperature. When both the front and rear glass thickness are increased by 0.5 mm, the cell temperature is increased by 0.41 (cid:1)C.

研究不足

1. The convective heat transfer coefficient is related to fluctuating wind speed and direction, and the steady-state thermal model cannot fully simulate the actual heat transfer situation. 2. The thermal resistances between thermocouples and PV modules also led to some measurement error. 3. It is difficult to measure the surface reflectivity accurately, and the calculation of internal heat source is not accurate enough.