Anti‐Environmental Aging Passive Daytime Radiative Cooling

Abstract

Passive daytime radiative cooling technology presents a sustainable solution for combating global warming and accompanying extreme weather, with great potential for diverse applications. The key characteristics of this cooling technology are the ability to reflect most sunlight and radiate heat through the atmospheric transparency window. However, the required high solar reflectance is easily affected by environmental aging, rendering the cooling ineffective. In recent years, significant advancements have been made in understanding the failure mechanisms, design strategies, and manufacturing technologies of daytime radiative cooling. Herein, a critical review on anti‐environmental aging passive daytime radiative cooling with the goal of advancing their commercial applications is presented. It is first introduced the optical mechanisms and optimization principles of radiative cooling, which serve as a basis for further endowing environmental durability. Then the environmental aging conditions of passive daytime radiative cooling, mainly focusing on UV exposure, thermal aging, surface contamination and chemical corrosion are discussed. Furthermore, the developments of anti‐environmental aging passive daytime radiative cooling materials, including design strategies, fabrication techniques, structures, and performances, are reviewed and classified for the first time. Last but not the least, the remaining open challenges and the insights are presented for the further promotion of the commercialization progress.

Recent advancements in radiative cooling textiles for personal thermal management

“…Passive radiative cooling (PRC) technology can reduce the temperature by concurrently reflecting sunlight (0.3–2.5 μm) and conducting heat radiation to outer space through the atmospheric transparent spectral window (ATSW: 8–13 μm), which is a promising outdoor cooling method without any extra energy input. 9–13 The integration of PRC technology into everyday wearable fabrics offers several benefits, i.e. , providing direct localized cooling to the wearers with enhanced comfort under extreme high-temperature conditions, as well as significantly contributing to energy conservation, environmental protection and new-materials industrial development.…”

Ultrahigh Visible-Transparency, Submicrometer, and Polymer-Free Radiative Cooling Meta-Glass Coating for Building Energy Saving

“…In addition, polymers suffer from the aging and reliability problem under long-term direct sunlight. 35 ITO-based TRC glass also depends on polymer materials to support high MIR emission and exhibits suboptimal VIS transparency (∼80%) and NIR reflection (∼55%). 25 29 They employed four different materials for the DM-based TRC glass, and the increased different material interfaces may be vulnerable to thermal and mechanical stresses.…”

“…Consequently, the introduction of polymer also increases the complexity of the fabrication process, as the fabrication process of polymer layers is incompatible with DMD layers, and micrometer-scale thickness coatings lead to poor economic viability. In addition, polymers suffer from the aging and reliability problem under long-term direct sunlight . ITO-based TRC glass also depends on polymer materials to support high MIR emission and exhibits suboptimal VIS transparency (∼80%) and NIR reflection (∼55%) .…”

Highly Stable Polyimide Composite Nanofiber Membranes with Spectrally Selective for Passive Daytime Radiative Cooling

“…To address the aggregate problem, materials with UV shielding performance, or hydrophobic properties have been incorporated into passive cooling materials. − For example, Hu et al obtained superhydrophobic and flexible poly­(vinylidene fluoride- co -hexafluoropropylene) [P­(VDF-HFP)]-based nanofiber film via a facile and scalable electrospinning technique with subsequent electrospraying SiO 2 nanoparticles. The resultant nanofiber film presented a sunlight reflection of 98.5% in the range of 0.3–2.5 μm and an average selective emissivity above 95% in the 8–13 μm.…”