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Common glass without spectral regulation effect cannot offer an energy‐saving function, and radiative cooling technology without visible transparency cannot satisfy the illumination and esthetic demands. Herein, the concept of utilizing a biomimetic beetle cuticle structure, guided by principles of Chinese Taoist philosophy, is proposed to accomplish efficient radiative regulation. Subsequently, low‐cost biomimetic radiative cooling (Bio‐RC) glass is presented, which can reduce the temperature of buildings throughout daytime by blocking near‐infrared (NIR) radiation, conveying visible light, and emitting heat within the atmospheric window. Utilizing only three layers of thin films, Bio‐RC glass achieves multi‐band spectral regulation, avoids a complicated preparation process, and has the potential for large‐scale production. Spectrometry reveals that Bio‐RC glass exhibits an effective visible light transmissivity of 80.5%, a mean NIR transmissivity of 10.3%, and an effective emissivity of 94.8% within the atmospheric window. A one‐month rooftop test demonstrates that Bio‐RC glass achieves a maximum cavity temperature reduction of 18.1 °C compared with common glass. Energy consumption analysis indicates that Bio‐RC glass can conserve approximately 23.4% of the total energy consumption per year compared with common glass. The proposed Bio‐RC glass can lower the temperature during daylight while preserving transparency and esthetics, making it suitable for application in buildings and vehicles. [ABSTRACT FROM AUTHOR]

By exploiting the 3 K coldness of outer space as heat sink of terrestrial thermal radiation, passive daytime radiative cooling (PDRC) can achieve sub-ambient temperatures without any energy consumption, and thus exhibiting extraordinary application potentials. By pursuing the dual-band (solar and atmosphere window) optical properties to approach ideal 100 %, PDRC can maximize dissipating long wavelength infrared radiation to space and minimize absorbing sunlight simultaneously. PDRC technology can reach146 W/m2 theoretical cooling power and up to 120 W/m2 during application. This article focuses on the fundamental physics mechanism of radiative transfer and natural radiative cooling phenomena. Methodologies of infrared absorption functional group selection, optical band gap selection for solar reflection, photon and phonon enhanced resonance by micro-structure were discussed in detail to give a comprehensive instructing strategy of radiative cooling power improvement. Although PDRC technology can achieve sum-ambient temperature cooling without consuming any energy, its drawbacks such as single function of cooling and high whiteness requirement needed to hinder its large-scale application. This article also outlines the current primary applications of PDRC technology, along with summarizing the challenges and potential opportunities it encounters in practical implementation. This paper aims to provide a comprehensive overview on the fundamental physical mechanisms, methods for enhancing its power output, as well as the current state and future developments of PDRC applications, providing potential guidance for reducing greenhouse gas emissions and energy consumption. • Advancements of radiative cooling technology were reviewed comprehensively. • Fundamental physics of passive radiative cooling was reviewed comprehensively. • Material selection methodology and optical mechanism were discussed in detail. • The recent application of passive daytime radiative cooling was reviewed. • Some current challenges and potential applications were presented and discussed. [ABSTRACT FROM AUTHOR]

Abstract Radiative cooling, as a passive cooling method, is an effective way to save energy and reduce emissions by dissipating heat into space through the "sky window," without consuming any additional energy. The actual particles in the radiative-cooling coating constitute a particle cloud with non-uniform size distribution and the cooling effect is greatly affected by the spectral reflectance of the actual substrate. Herein, the radiative transfer of actual SiO 2 particles doped with a radiative-cooling coating was initially studied. Monte Carlo ray-tracing method, combined with Mie theory, was used to analyze the influence of particle size, volume fraction of particles, coating thickness, and different substrate reflectances on the spectral radiative characteristics of the radiative-cooling coating. The particles size distribution and spectral substrate reflectance were considered. The numerical results show that the maximum spectral reflectance difference between a coating with a uniform-size-distribution particle cloud and a coating with a non-uniform-size-distribution particle cloud can reach 27.3%. Furthermore, the influence of particle parameters and reflectance of the substrate on the radiative characteristics of the radiative-cooling coating is mainly concentrated in the 10–12 μm band. At 8–10 μm and 12–13 μm, the radiative-cooling coating emissivity varies little with the change of particle parameters and the reflectance of substrate, which is induced by the strong absorption of SiO 2 particles. [ABSTRACT FROM AUTHOR]