Radiative cooling by tailoring surfaces with microstructures

TL;DR

This paper presents a design for radiative cooling surfaces that reflect sunlight and emit infrared radiation in atmospheric transparency windows, achieving significant cooling power.

Contribution

It introduces a novel combination of gratings and multi-layer structures using BN, SiC, and SiO2 to optimize radiative cooling performance.

Findings

Achieves up to 80 W/m^2 cooling power density

Design effectively reflects solar spectrum and emits in the 8-13 μm window

Uses optimized nanostructures for enhanced radiative cooling

Abstract

We propose in this article a method to generate radiative coolers which are reflective in the solar spectrum and emissive in the transparency window of the atmosphere (8-13 $\mu$m). We choose an approach combining thermal control capacity of gratings and multi-layers. We use optimized BN, SiC and SiO 2 gratings, which have emissivity peak in the transparency window. We place under these gratings a metal/dielectric multi-layer structure to obtain a near perfect reflectivity in the solar spectrum and to enhance the emissivity in the transparency window. The optimized structures produce a good radiative cooling power density up to 80 W.m --2 .