Performance of passive daytime radiative cooling coating with CaSiO3 enhanced solar reflectivity and atmospheric window emissivity

Abstract

Abstract Passive daytime radiative cooling (PDRC) emerges as an environmentally friendly cooling strategy for its zero demand of electricity and fossil energy. In this study, PDRC coating containing polymethylmethacrylate and CaSiO3 was prepared with a simple process at low cost. The solar reflectivity, atmospheric window emissivity and radiative cooling performance of the prepared coating were investigated. The coating exhibits an average solar reflectance of 96.4% and an average atmospheric window emittance of 97.0%. Under direct solar irradiation, the coating can achieved an average sub-ambient temperature drop of 5.5 °C and an average net radiative cooling power of 72 W m−2. The results are on par with those of the efficient radiative coolers in the literature. Experimental investigation also suggests that the coating has application prospect in dew condensation and retarding the melting process of ice. This study provides a cost-efficient and commercially feasible strategy to fabricate PDRC coating.