Performance investigations of the easily manufactured composite all-day radiative cooling materials based on PDMS

Abstract

The passive radiative cooling technology can be employed to obtain the cooling capacity without any energy consumption, which has been garnering significant attention nowadays. This work proposes and experimentally studies the all-day radiative cooling material based on layered composite material made from Polydimethylsiloxane (PDMS). This work adds SiO₂ nano-particles, which act as visible light scatters, and the proposed film can realize an excellent all-day cooling capacity when the thicknesses of the PDMS and Al films are respectively chosen as 200 μm and 4 μm, and the concentration of the SiO₂ particles in the film is 40 %. The theoretical explorations indicated that the presented composite film can exhibit the high reflectivity (90.36 %) and emissivity (90.19 %) in the visible spectrum and atmospheric transparency window (ATW) spectrum. Under direct sunlight of a highest solar irradiance of 688.89 W/m², there is an average temperature difference between cooling film and white paper of 6.3 °C. Furthermore, in clear weather conditions at night with an average humidity level of 58.15 %, it can generate a temperature difference of 4.8 °C. This work proposes an easily manufactured and eco-friendly all-day radiative cooling material, which has the potential applications in future refrigeration technology.