scholarly journals A structural polymer for highly efficient all-day passive radiative cooling

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Tong Wang ◽  
Yi Wu ◽  
Lan Shi ◽  
Xinhua Hu ◽  
Min Chen ◽  
...  
Keyword(s):  
Low Cost ◽  
Outer Space ◽  
Cooling Power ◽  
Radiative Cooling ◽  
Pmma Film ◽  
Thermal Emittance ◽  
Highly Efficient ◽  
Solar Reflectance ◽  
Solar Intensity ◽  
Porous Array

AbstractAll-day passive radiative cooling has recently attracted tremendous interest by reflecting sunlight and radiating heat to the ultracold outer space. While some progress has been made, it still remains big challenge in fabricating highly efficient and low-cost radiative coolers for all-day and all-climates. Herein, we report a hierarchically structured polymethyl methacrylate (PMMA) film with a micropore array combined with random nanopores for highly efficient day- and nighttime passive radiative cooling. This hierarchically porous array PMMA film exhibits sufficiently high solar reflectance (0.95) and superior longwave infrared thermal emittance (0.98) and realizes subambient cooling of ~8.2 °C during the night and ~6.0 °C to ~8.9 °C during midday with an average cooling power of ~85 W/m2 under solar intensity of ~900 W/m2, and promisingly ~5.5 °C even under solar intensity of ~930 W/m2 and relative humidity of ~64% in hot and moist climate. The micropores and nanopores in the polymer film play crucial roles in enhancing the solar reflectance and thermal emittance.

scholarly journals Biologically inspired flexible photonic films for efficient passive radiative cooling

2020 ◽  
Vol 117 (26) ◽  
pp. 14657-14666 ◽  
Author(s):  
Haiwen Zhang ◽  
Kally C. S. Ly ◽  
Xianghui Liu ◽  
Zhihan Chen ◽  
Max Yan ◽  
...  
Keyword(s):  
High Throughput ◽  
High Performance ◽  
Low Cost ◽  
Cooling Power ◽  
Radiative Cooling ◽  
Fundamental Parameter ◽  
Photonic Materials ◽  
Biologically Inspired ◽  
Thermoregulatory Function ◽  
Wearable Products

Temperature is a fundamental parameter for all forms of lives. Natural evolution has resulted in organisms which have excellent thermoregulation capabilities in extreme climates. Bioinspired materials that mimic biological solution for thermoregulation have proven promising for passive radiative cooling. However, scalable production of artificial photonic radiators with complex structures, outstanding properties, high throughput, and low cost is still challenging. Herein, we design and demonstrate biologically inspired photonic materials for passive radiative cooling, after discovery of longicorn beetles’ excellent thermoregulatory function with their dual-scale fluffs. The natural fluffs exhibit a finely structured triangular cross-section with two thermoregulatory effects which effectively reflects sunlight and emits thermal radiation, thereby decreasing the beetles’ body temperature. Inspired by the finding, a photonic film consisting of a micropyramid-arrayed polymer matrix with random ceramic particles is fabricated with high throughput. The film reflects ∼95% of solar irradiance and exhibits an infrared emissivity >0.96. The effective cooling power is found to be ∼90.8 W⋅m−2and a temperature decrease of up to 5.1 °C is recorded under direct sunlight. Additionally, the film exhibits hydrophobicity, superior flexibility, and strong mechanical strength, which is promising for thermal management in various electronic devices and wearable products. Our work paves the way for designing and fabrication of high-performance thermal regulation materials.

scholarly journals Highly effective photon-to-cooling thermal device

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Yanpei Tian ◽  
Lijuan Qian ◽  
Xiaojie Liu ◽  
Alok Ghanekar ◽  
Gang Xiao ◽  
...  
Keyword(s):  
Thin Film ◽  
Thermal Structure ◽  
Outer Space ◽  
Temperature Drop ◽  
Transparency Window ◽  
Cooling Power ◽  
Radiative Cooling ◽  
Atmospheric Transparency ◽  
Cooling Method ◽  
Highly Effective

AbstractPhoton-to-cooling phenomenon relies on the atmospheric transparency window to dissipate heat from the earth into outer space, which is an energy-saving cooling technique. This work demonstrates a highly effective aluminized Polymethylpentene (PMP) thin-film thermal structure. The emissivity of aluminized PMP thin films matches well to the atmospheric transparency window so as to minimize parasitic heat losses. This photon-to-cooling structure yields a temperature drop of 8.5 K in comparison to the ambient temperature and a corresponding radiative cooling power of 193 W/m2 during a one-day cycle. The easy-to-manufacture feature of an aluminized PMP thin film makes it a practically scalable radiative cooling method.

scholarly journals Simple PDMS/AIN emitter as a passive daytime radiative cooling design

2021 ◽  
Author(s):  
Mabchour ◽  
benlattar mourad
Keyword(s):  
Outer Space ◽  
Solar Spectrum ◽  
Ambient Air ◽  
Heat Radiation ◽  
Cooling Power ◽  
Radiative Cooling ◽  
Spectral Selectivity ◽  
Solar Energy Harvesting ◽  
Atmospheric Window ◽  
Cooling Design

Abstract Radiative cooling is a passive cooling purpose where a surface naturally cools by radiating the mid-infrared heat radiation to the cold outer space through the atmospheric window . Daytime passive radiative cooling technologies can be simply provided by using a multi-layer design that emits strongly in the transparency atmospheric window, while presents high reflectance in the solar spectrum . In this study, we propose a polydimethylsiloxane foil ) coated aluminum nitride (AIN) deposed onto silver (Ag) coated glass as a radiative cooler for enhancing both daytime and nighttime radiative cooling performances. The spectral selectivity of the proposed device was obtained using matrix method. Numerical results show that our proposed design can reflect more than 96 % in the solar spectrum, while its average emissivity in the atmospheric window can reach more than 90 %.In the absence of wind speed, the proposed device can achieve a net cooling power of under direct sunlight, cooling to a below the ambient air temperature. At nighttime, the proposed device temperature can drop by below the ambient, leading to a net cooling power of . Therefore, the proposed radiative design can fundamentally enable new methods for exploiting solar energy harvesting and energy conservation.

MOF-derived M-OOH with rich oxygen defects by in-situ electro-oxidation reconstitution for highly efficient oxygen evolution reaction

2021 ◽  
Author(s):  
Zhikai Shi ◽  
Zebin Yu ◽  
Ronghua Jiang ◽  
Jun Huang ◽  
Yanping Hou ◽  
...  
Keyword(s):  
Oxygen Evolution ◽  
Oxygen Evolution Reaction ◽  
Energy Production ◽  
Low Cost ◽  
Highly Efficient ◽  
Oxygen Defects ◽  
Electro Oxidation

The oxygen evolution reaction (OER) is an important half-reaction in the field of energy production. However, how effectively, simply, and greenly to prepare low-cost OER electrocatalysts remains a problem. Herein,...

scholarly journals Experimental development and testing of low-cost scalable radiative cooling materials for building applications

2021 ◽  
Vol 230 ◽  
pp. 111209
Author(s):  
Laura Carlosena ◽  
Ángel Andueza ◽  
Luis Torres ◽  
Olatz Irulegi ◽  
Rufino J. Hernández-Minguillón ◽  
...  
Keyword(s):  
Low Cost ◽  
Radiative Cooling ◽  
Experimental Development

Embedding metal foam into metal–organic framework monoliths for triggering a highly efficient release of adsorbed atmospheric water by localized eddy current heating

2021 ◽  
Author(s):  
Yingle Tao ◽  
Qiangqiang Li ◽  
Qiannan Wu ◽  
Haiqing Li
Keyword(s):  
Thermal Insulation ◽  
Eddy Current ◽  
Energy Efficient ◽  
Metal Foam ◽  
Low Cost ◽  
Metal Organic Framework ◽  
Atmospheric Water ◽  
Highly Efficient ◽  
Metal Organic ◽  
Eddy Current Heating

Localized eddy current heating delivered by metal foam embedded in a MOF monolith provides a novel, low-cost, and energy efficient way to overcome the thermal insulation nature of MOF monoliths and realize their highly efficient regenerations.

Conductive 3D sponges for affordable and highly-efficient water purification

Nanoscale ◽  
2018 ◽  
Vol 10 (10) ◽  
pp. 4771-4778 ◽  
Author(s):  
Yanbiao Liu ◽  
Fang Li ◽  
Qin Xia ◽  
Jiawei Wu ◽  
Jianshe Liu ◽  
...  
Keyword(s):  
Organic Pollutants ◽  
Water Purification ◽  
Low Cost ◽  
Highly Efficient ◽  
Electro Oxidation ◽  
Conductive Nanomaterials ◽  
Filtration Device

We developed a low-cost method to achieve efficient organic pollutants degradation by incorporating conductive nanomaterials to assist electro-oxidation, leading to an efficient conductive nano-sponge filtration device.

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