Radiative cooling gray paint with high solar reflectance for thermal management of electronic equipment

Abstract

Colored appearance is an ongoing pursue for the devising of radiative cooling paint (RCP), while the inevitable absorption of solar radiation remains a huge hurdle to meet the threshold of RCP under intense sunlight. Gray is one of the most common color for the equipment appearance in the industrial design, but rarely works have been made to explore the potential of gray radiative cooling paint integrated on the engineering equipment. Herein, we utilize the poly (vinylidene fluoridehexafluoropropylene)-acrylic (PVDF-HFP-PMMA) containing yttria particle and commercial dye to fabricate radiative cooling gray paint (RCGP). The porous structure in paint endows an effective light scattering of sunlight, and the high refractive index and wide bandgap of yttria further promote the reflection of visible light. As a result, the RCGP with a grayscale value of 237 exhibits a high reflectance beyond 0.89 in solar waveband and a high emittance over 0.96 in the atmospheric transparence window (ATW, 8–13 μm). We theoretically and experimentally explore the cooling potential of RCGP on a heat sink module of outdoor base station, yielding a distinctive temperature drop beyond 10 ℃. Our work provides a feasible strategy for minimizing the adverse effect from the color on the reflective property, and makes tentative and significant exploration of radiative cooling in engineering thermal management.