Comprehensive research on a simple and efficient radiative cooling driving thermoelectric generator system for nighttime passive power generation

Abstract

Radiative cooling (RC) technology has broad application prospects because it does not require any energy input, which has drawn much attention from researchers. Thermoelectric generators (TEGs) can convert the temperature gradient directly into electrical energy without negatively affecting the environment. It is feasible and meaningful to combine RC device with TEGs to realize passive power generation. In the present study, we have developed a radiative cooling driving thermoelectric generator (RC-TE) system that is simple in structure and easy to manufacture. A continuous nighttime experiment was performed to evaluate the thermal and electrical performance of the RC-TE system by using a self-made device. Experimental results indicate that the temperature of the TEG cold side in contact with the radiative cooler can be at most 7.8 °C lower than the ambient temperature. The maximum temperature difference between the hot and cold sides of TEG can reach 2.7 °C, which corresponds to an open circuit voltage of 73 mV. Furthermore, an analytical all-parameter model considering the thermal resistance of all components has been established to investigate the effects of different parameters (wind velocity, ambient temperature, relative humidity, load resistance, area ratio, structure parameter of TEG leg, and number of TEG leg pairs) on system performance. This study has guiding significance for the improvement and optimization of experimental devices, and can provide a new thinking and some practical guidelines for the design and application of the RC-TE system.