Radiative cooling

Materials science

Passive cooling

Radiative transfer

Thermodynamics

Physics

Optics

Thermal

Lightness

International Journal of Thermal Sciences

Radiative cooling, which aims at cooling objects by radiating heat into the outer space through the atmosphere window, has garnered wide interests since it is a passive refrigeration mode without extra energy consumption. However, most of the proposed structures, to maximize the cooling performance, are in white color, which may limit their practical applications due to some aesthetic consideration. To reveal the competing role between color display and radiative cooling performance, we take a metal-dielectric-metal (MDM) colored radiative cooler structure as representative to explore how the structure parameters influence the cooling performance and color display respectively, and clarify the key parameters for the desired performance. Moreover, the reflectance of the colored radiative cooler is identified as peak- and valley-types to clarify the color display performance. The Spearman rank order correlation coefficients between radiative cooling performance and the CIE-LCH color space parameters (lightness, chroma, and hue) are calculated, revealing that the lightness plays a dominant role. The present study is expected to reveal the competing role of radiative cooling power and color display, and trigger the practical applications of radiative cooling technologies.

Colored radiative cooling: How to balance color display and radiative cooling performance