Realization of an Adaptive Radiative Cooler with a Multilayer-Filter VO2-Based Fabry–Pérot Cavity

Abstract

A high-performance adaptive radiative cooler comprising a multilayer-filter VO2-based Fabry–Pérot (FP) cavity is proposed. The bottom FP cavity has four layers, VO2/NaCl/PVC/Ag. Based on the phase transition of VO2, the average emissivity in the transparent window can be switched from 3.7% to 96.3%. Additionally, the average emissivity can also be adjusted with external strain to the PVC layer, providing another way to attain the desired cooling effect. An upper filter is included to block most of the solar radiation and provide a transmittance of 96.7% in the atmospheric window. At high temperature, the adaptive emitter automatically activates radiative cooling. The net cooling power is up to 156.4 W⋅m−2 at an ambient temperature of 303 K. Our adaptive emitter still exhibits stable selective emissivity at different incident angles and heat transfer coefficients. At low temperature, the radiative cooling automatically deactivates, and the average emissivity decreases to only 3.8%. Therefore, our work not only provides new insights into the design of high-performance adaptive radiative coolers but also advances the development of intelligent thermal management.