Effective radiative cooling with ZrO2/PDMS reflective coating

Abstract

Radiative cooling (RC) has attracted growing attention in recent years since it is a terrestrial object that radiates heat to outer space through the atmospheric window while maintaining zero-energy consumption. It emits or absorbs radiation only in the atmospheric window (8–13 μm) and suppress it beyond this band. In this paper, we present a radiative cooling coating composed of a zirconia (ZrO 2 ) embedded polydimethylsiloxane (PDMS) hybrid ZrO 2 /PDMS coating. The influences on radiative cooling by particle sizes and volume fractions and film thicknesses are evaluated via Mie scatter theory combined with Monte Carlo ray-tracing method. The ZrO 2 /PDMS coatingdis plays a surface temperature drop 10.9 °C at the solar intensity of 895 W/m 2 , much better than the commercial white paint (4.4 °C). As it performs efficiently above ambient temperature and is easy to manufacture this coating, this coating may have some promising future for potential large-scale application of radiative cooling technology on energy-saving buildings. • Mie scatter theory combined with Monte Carlo simulation is used to analyse the optical properties of particles (ZrO 2 ) embedded into polymers (PDMS). • Preparation of coating is simple. • Reflectivity of coating (300–1350 nm) is about 93.55% and emissivity (2–25 μm) reaches 92.25%. • Temperature drops of 10.9 °C is achieved under the solar intensity of about 895 W/m 2 . • Temperature inside the house model with the coating is about 4.2 °C lower than that of commercial paints.