Self-adaptive radiation recuperator with double phase transition temperature switches based on VO2 intelligent films

Abstract

Developing renewable energy for heating and cooling to achieve carbon neutrality and environmental protection is of great significance. The combination of photothermal (PT) and radiative cooling (RC) technology to continuously obtain energy throughout the day is gradually attracting interest, in which vanadium dioxide (VO2) intelligent phase transition film serves as a bridge between the daytime PT mode and the nighttime RC mode. The high phase transition temperature of VO2 poses a challenge to environmental adaptability and dynamic switching in practical applications. In this work, a novel self-adaptive radiation recuperator with double phase transition temperature (37 °C and 68 °C) switches is proposed to exchange energy from the sun and outer space by radiation. Compared with VO2 and W-doped VO2 single-layer structure, this method has a higher self-adaptability to easily achieve the phase transition temperature of mode switching. The absorptivity of the radiation recuperator is 0.75 in the solar band (0.3–2.5 μm), and the emissivity switching capability is present from 0.3 to 0.86 in the atmospheric window band (8–14 μm). The transition mode generated by the presence of double phase transition temperature improves temperature self-adaptability and improves energy collection efficiency in dynamic environments.