Comprehensive research on a high performance solar and radiative cooling driving thermoelectric generator system with concentration for passive power generation

In this paper, to solve the problem that the power generation of currently developed all-day radiative cooling driving thermoelectric generator (RC-TEG) devices is very small, a promising concentrating RC-TEG (C-RC-TEG) device was demonstrated based on high radiation and thermal concentration. The experimental prototype was established, using the local effect of solar energy and radiative cooling to generate relatively high temperature difference driving the TEG to generate electricity. Outdoor experimental results show that the maximum temperature difference is about 4.5 °C and the maximum open-circuit is about 56 mV. Meanwhile, we use the established mathematical model verified by experiments to deeply explore the factors affecting its efficiency. The simulation results show solar irradiance and radiative cooling area have a positive effect on the C-RC-TEG model. As the wind speed increases, the power generation of C-RC-TEG drops from 8.58 mW to 6.96 mW. The maximum power generation and temperature difference can be up to 47 mW and 7 K by concentrator in the area of light focusing of 0.003 m2. The results indicate concentrating contributes to the improvement of RC-TEG performance. Our work provides a promising new way of comprehensive guidance on achieving effective conversion of solar energy and radiative cooling into electricity.