Daytime passive radiative cooling materials based on disordered media: A review

Sun, Junyu; Wang, Jing; Guo, Taotao; Bao, Hua; Bai, Shuxin

doi:10.1016/j.solmat.2021.111492

Cited by 31 publications

(11 citation statements)

References 40 publications

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“…In order to achieve high radiative cooling performance and daytime sub‐ambient cooling, the coating needs to meet three conditions as follows 28 :…”

Section: Resultsmentioning

confidence: 99%

Geopolymer‐based sub‐ambient daytime radiative cooling coating

Yang

Xue

et al. 2022

EcoMat

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Sub-ambient daytime radiative cooling coating (SDRCC) is an appealing thermal management technology with great potential for alleviating the global warming and urban heat island effect. Over the past few years, various polymeric SDRCCs have been developed. However, they may face problems of environmental aging under UV and moisture due to their organic nature. In this study, an ambient-cured inorganic geopolymer-based SDRCC was synthesized with the modification of barium sulfate (BaSO 4 ) and nano-silica (SiO 2 ) particles. The optical and physicochemical properties were systematically investigated. The chemical composition, functional groups, surface morphologies of the raw materials, and the formed geopolymer coating were characterized by XRD, FTIR, SEM, and EDS. The developed coating exhibits a high infrared emissivity of 0.9491 and solar reflectance of 97.6%. When exposed to direct sunlight, the coating's surface could cool down up to 8.9 C below the ambient air temperature under Hong Kong's climate. In addition, the coating could retain well its performance under a variety of harsh environments, including high temperature, water immersion, mechanical wearing, and exposure to sunlight.

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“…In order to achieve high radiative cooling performance and daytime sub‐ambient cooling, the coating needs to meet three conditions as follows 28 :…”

Section: Resultsmentioning

confidence: 99%

Geopolymer‐based sub‐ambient daytime radiative cooling coating

Yang

Xue

et al. 2022

EcoMat

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“…A recently proposed type of polymeric structure at which porosity of the polymer was artificially engineered was shown to be effective in achieving solar irradiance reflection and emission in the atmospheric transparency window simultaneously. − While holes inside the structure act as a cavity at longer wavelengths, they exhibit a large bandgap and lead to broadband reflection in visible and near-infrared spectra at which solar irradiance is strong. Eliminating the need for an additional metallic layer is a major step toward large scale fabrication feasibility, thus allowing practical realization of passive radiative cooling coatings with readily available approaches and formats, such as paints …”

Section: Introductionmentioning

confidence: 99%

Spectral Emissivity Profiles for Radiative Cooling

Kecebas,

Menguc,

Sendur

2023

ACS Appl. Opt. Mater.

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Passive radiative cooling, an innovative approach for cooling buildings and devices, has attracted considerable attention in recent years. In particular, the spectral emissivity distribution of surfaces plays a crucial role for an object to radiate at wavelengths for which the atmosphere is transparent and solar irradiance is low. Here, we study the role of spectral emissivity distributions using different performance metrics: cooling power (CP) and equilibrium temperature (T Eq). We investigated the roles of environmental factors, such as ambient temperature and level of thermal insulation from surroundings, on spectral emissivity distributions. Based on these emissivity distributions, we report the conditions at which the suitable profile for cooling power maximization and equilibrium temperature minimization changes. We discuss the realization of spectral emissivity distributions using various optical materials for cooling power maximization and equilibrium temperature minimization separately under different environmental conditions. The impacts of material selection on the realization of desired emissivity profiles and corresponding outcomes are analyzed. As progress in this emerging field gains traction, development of radiative cooling structures with suitable spectral emissivity profiles under different circumstances will become essential.

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“…Bioinspired surfaces with microscale or nanoscale structures have widespread applications because of their unique properties, for example, self-cleaning, , energy harvesting, − thermal management, , radiative cooling, , drag reduction, , and reversible adhesion . The droplets deposited on the lotus leaf or rose petal both exhibit a high contact angle (>150°).…”

Section: Introductionmentioning

confidence: 99%

Molecular Dynamics Simulation on the Wettability of Nanoscale Wrinkles: High Water Adhesion of Rose Petals

et al. 2022

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Understanding the high water adhesion of rose petals is of great significance in artificial surface design. With all-atom molecular dynamics simulation, the wettability of nanoscale wrinkles was explored and compared to that of nanoscale strips with favorable hydrophobicity. The dewetting and wetting of gaps between nanoscale structures represent the Cassie–Baxter (CB) and Wenzel (WZ) states of the macroscopic droplet deposited on the textured surface, respectively. We uncovered the intermediate state, which is different from the CB and WZ states for wrinkles. Structures and free-energy profiles of metastable and transition states under various pressures were also investigated. Moreover, free-energy barriers for the (de)wetting transitions were quantified. On this basis, the roles of pressure and the unique structures of nanoscale wrinkles in the high water adhesion of rose petals were identified.

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Daytime passive radiative cooling materials based on disordered media: A review

Cited by 31 publications

References 40 publications

Geopolymer‐based sub‐ambient daytime radiative cooling coating

Geopolymer‐based sub‐ambient daytime radiative cooling coating

Spectral Emissivity Profiles for Radiative Cooling

Molecular Dynamics Simulation on the Wettability of Nanoscale Wrinkles: High Water Adhesion of Rose Petals

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