Atmospheric water harvesting (AWH) has received tremendous interest because of population growth, limited freshwater resources, and water pollution. However, key challenges remain in developing efficient, flexible, and lightweight AWH materials with scalability. Here, we demonstrated a radiative cooling fabric for AWH via its hierarchically structured cellulose network and hybrid sorption-dewing mechanisms. With 8.3% solar absorption and ∼0.9 infrared (IR) emissivity, the material can drop up to 7.5 °C below ambient temperature without energy consumption via radiative cooling. Water adsorption onto the hydrophilic functional groups of cellulose is dominated by sorption at low relative humidity (RH) and dewing at high RH. The cellulose network provides desirable mechanical properties with entangled high-aspect-ratio fibers over tens of adsorption-extraction cycles. In the field test, the cellulose sample exhibited water uptake of 1.29 kg/kg at 80% RH during the night. The profusion of radiative cooling fabric features desirable cost effectiveness and allows fast deployment into large-scale AWH applications.
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http://dx.doi.org/10.1021/acs.nanolett.1c04143 | DOI Listing |
Adv Mater
December 2024
Key Laboratory of Material Chemistry for Energy Conversion and Storage, Ministry of Education, Hubei Key Laboratory of Material Chemistry and Service Failure and Hubei Engineering Research Center for Biomaterials and Medical Protective Materials, Huazhong University of Science and Technology, Wuhan, 430074, P. R. China.
The development of zero-power moisture-harvesting technology in an unsaturated atmosphere is of great significance for coping with global freshwater scarcity. Here, inspired by Pachydactylus rangei's (Namib sand gecko) ability to evade thermal radiation and harvest moisture, a power-free cooling moisture harvester (PFCMH) is fabricated using the continuous, industrialized micro-extrusion compression molding. A Luneburg lens is introduced in the PFCMH for the first time, endowing it with a high reflectivity of ≈92.
View Article and Find Full Text PDFInt J Biol Macromol
December 2024
Jiangsu Optoelectronic Functional Materials Engineering Research Center, School of Chemistry and Chemical Engineering, Southeast University, Nanjing 211189, China. Electronic address:
Passive radiative cooling (PRC) is an emerging sustainable technology that plays a key role for achieving the goal of carbon neutrality. However, several challenges remain for PRC materials in their practical application in building thermal management, including overcooling problems and unsatisfactory cooling efficiency caused by solar absorption and parasitic heat gains. In this work, fluorinated cellulose-based composite aerogels (FCCA) integrating thermal insulation and PRC were developed by a facile manufacturing strategy that combined phase separation and freeze-drying.
View Article and Find Full Text PDFACS Nano
December 2024
School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China.
Ultrafast thermal switches are pivotal for managing heat generated in advanced solid-state applications, including high-speed chiplets, thermo-optical modulators, and on-chip lasers. However, conventional phonon-based switches cannot meet the demand for picosecond-level response times, and existing near-field radiative thermal switches face challenges in efficiently modulating heat transfer across vacuum gaps. To overcome these limitations, we propose an ultrafast thermal switch design based on pump-driven transient polaritons in asymmetric terminals.
View Article and Find Full Text PDFACS Omega
December 2024
Department of Energy Science and Engineering, Indian Institute of Technology Bombay, Mumbai 400076, Maharashtra, India.
The cooling power of radiative cooling (RC) coatings depends not only on the radiative properties of the coating but also on environmental variables. In tropical environments, the cooling performance of RC coatings deteriorates due to high humidity and high solar radiation. Previous studies focused on developing high solar-reflective coatings to achieve subambient cooling in tropical environments.
View Article and Find Full Text PDFACS Omega
December 2024
Department of Biomedical Engineering, Universidad de los Andes, Bogotá 111711, Colombia.
Exposure to high temperatures during indoor and outdoor activities increases the risk of heat-related illness such as cramps, rashes, and heatstroke (HS). Fatal cases of HS are ten times more common than serious cardiac episodes in sporting scenarios, with untreated cases leading to mortality rates as high as 80%. Enhancing thermal comfort can be achieved through heat loss in enclosed spaces and the human body, utilizing heat transfer mechanisms such as radiation, conduction, convection, and evaporation, which do not require initial energy input.
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