Design and experimental validation of an all-day passive thermoelectric system via radiative cooling and greenhouse effects

An all-day passive thermoelectric system based on ultra-cold outer space and solar sunshine is designed. A thin film made from the mixture of silica microparticles and the liquid acrylic resin, which exhibits a pronounced passive radiative cooling (PRC) effect, is coated onto the sky-faced end of the thermoelectric generator (TEG) to decrease its temperature. Meanwhile, the other ground-faced TEG end is settled into a greenhouse and reaches a higher temperature than the sky-faced end. The integration of PRC and greenhouse effects increases the temperature difference between the TEG ends and thus the output power. The proposed passive TEG system is experimentally constructed, and its performance during the 24-h test cycle is validated. Experimental data show that the proposed system can passively produce an all-day continuous power generation of 90.74 mW m −2. This study presents a conception design and performance validation of an all-day passive TEG and paves further guidance for performance enhancement of the proposed electricity generation system.