Power characteristics of photovoltaic modules of solar-powered airplanes including thermal effects

A power characteristic model of photovoltaic (PV) modules on the wing of solar-powered airplanes operated from sea level to the stratosphere is established. Because the efficiency of PV modules is a function of surface temperature, the proposed model includes thermodynamic effects. Firstly, the real-time power characteristics are analyzed at the altitudes of 10 km and 30 km and during the summer and winter solstice. Then, further investigations are conducted to research the daily averaged power per unit area from 0 km to 35 km throughout a whole year. The results show that the low atmosphere temperature is favorable condition for PV modules to obtain high absorption efficiency, and total solar radiation increases with the altitude increasing. However, the thinness of atmosphere density at high altitudes leads the deduction of Reynolds number, resulting in less heat carried away and the efficiency deterioration of PV modules. The maximum power collected occurs around 11 km. The research work shows that it is necessary to take into consideration the thermal effects on the efficiency of PV modules at high altitudes.