Bioinspired Radiative Cooling Structure with Randomly Stacked Fibers for Efficient All-Day Passive Cooling

Yang, Zhangbin; Zhang, Jun

doi:10.1021/acsami.1c12267

Cited by 57 publications

(41 citation statements)

References 43 publications

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“…P cond+conv is the nonradiative power density caused by thermal conduction and convection between surrounding media and the radiator. , where h c is the nonradiative heat transfer coefficient, derived from the conductive and convective heat exchange between the radiator and surrounding media, and . − The cooling temperature ( ) is calculated by the extraction of the cooling temperature under the condition .…”

Section: Resultsmentioning

confidence: 99%

Ordered-Porous-Array Polymethyl Methacrylate Films for Radiative Cooling

Tan

et al. 2022

ACS Appl. Mater. Interfaces

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Passive radiative cooling is a spontaneous pattern of reflecting sunlight and radiating heat into the cold outer space through transparent atmosphere windows. In this work, an ordered-porous-array polymethyl methacrylate (OPA-PMMA) film with the properties of excellent radiative cooling is designed and studied. An ultra-high emissivity of 98.4% in the mid-infrared region (3–25 μm) and a good solar reflectance of 85% in the ultraviolet and near-infrared solar spectra (0.2–2.5 μm) were achieved. The surface temperature of the OPA-PMMA film is 16 °C lower than that of the smooth-surface PMMA films and is 8.6 °C lower than that of the commercial white paint in the outdoor test. The structure of the OPA plays an important role in improving solar reflectivity and emissivity. The films are fabricated using a one-step low-cost process that can be applied for large-scale production. It is vital for promoting radiative cooling as a viable energy technology for buildings, fabric, or equipment that need a cooling environment.

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Section: Resultsmentioning

confidence: 99%

Ordered-Porous-Array Polymethyl Methacrylate Films for Radiative Cooling

Tan

et al. 2022

ACS Appl. Mater. Interfaces

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“…Because of the refractive index difference between PP ( n ≈ 1.5) and air ( n ≈ 1), random PP fibers, with broad distributions centered at 2.10 μm, strongly scatter sunlight of all wavelengths (Figure b). Our previous works mainly focused on the construction of nonselective radiative cooling structures, which was realized by reducing the pore size or building a coating on the top surface. , Although both the nonselective emitter and selective emitter are desirable for radiative cooling to achieve the subambient cooling effect, the selective emitter is more efficient. Effective, strong emission only in the ATW can be useful and achieve higher theoretical temperature reduction (Figure S1, Section S4).…”

Section: Resultsmentioning

confidence: 99%

Hierarchical-Morphology Metal/Polymer Heterostructure for Scalable Multimodal Thermal Management

Yang

Zhang

2022

ACS Appl. Mater. Interfaces

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The cooling and heating energy consumption of buildings poses a serious threat to the energy supply and increases greenhouse gas emissions, thus adversely impacting global warming and the long-term climate change trends. Here, inspired by the structure of the louver, this work demonstrates a multimodal device that integrates radiative cooling, natural lighting, and solar heating to deal with the grand challenge of building energy consumption. The blades integrate a selective radiative cooling material with a solar heating material. The selective radiative cooling material (solar reflectance ∼97%, selective emittance ∼0.82 in the 8−13 μm waveband) combines a solar reflective melt-blown polypropylene film and a solar transparent mid-infrared emitter polyethylene/ silicon dioxide film. In addition, the heating material (solar absorptance ∼91%, thermal emittance ∼0.04) is zinc (Zn) film deposited with copper (Cu) nanoparticles, based on the Cu−Zn galvanic-displacement reaction. Hence, by rotating the blades, the conversion of radiative cooling, solar heating, and natural lighting functions can be realized. In the daytime, the multimodal device displays a subambient temperature of 4 °C, a superambient temperature of 2 °C, and a superambient temperature of 5 °C for the cooling mode, transmitting mode, and solar heating mode, respectively. On the basis of the energy-savings simulation, integrating these modes and dynamic converting these modes in the corresponding climate could save ∼746 GJ in the contiguous United States for one year (38% of the baseline energy consumption), which is equivalent to ∼147 tons of carbon dioxide emission reduction. Because of its excellent multimodal thermal management performance, this multimodal device will push forward the transformative change of building thermal management toward decarbonization and sustainability and being more green.

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“…For commercial applications, RSC technology witnessed a severe challenge that cooling materials exhibit low radiative cooling power of ≈100 W m −2 , even without solar heating. [45,[107][108][109][110] The challenge is mainly stemming from the high radiative heating from the surrounding, which is inevitable for the overwhelming majority of cooling materials according to Kirchhoff's law. The low power density of this technology has compromised their superiority in clean cooling and placed great restrictions on the prospects of this technology.…”

Section: Hydrogel Materialsmentioning

confidence: 99%

Micro‐Nano Porous Structure for Efficient Daytime Radiative Sky Cooling

Liu

Tang

Jiang

et al. 2022

Adv Funct Materials

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CO 2 in 2050. [5] Due to the second law of thermodynamics, cooling is generally more challenging than heating. Conventional vapor-compression cooling not only results in excessive energy consumption, accelerating the depletion of fossil fuels, but also degrades the atmospheric ozone, leading to notorious environmental issues. Therefore, developing novel and pollutionfree cooling technology has become an urgent demand in the following decades.Radiative sky cooling (RSC) can harvest the coldness of the universe via the 8-13 µm atmospheric window without any pollution and energy consumption, which has witnessed great progress in the last few years. [6][7][8] Since the first demonstration of daytime radiative cooling via multilayer photonic structure by Fan and co-workers in 2014, this facile cooling technology has drawn worldwide attention. [9,10] With the joint efforts, RSC technology has achieved striking advances in building cooling, [4,11] photovoltaic cooling, [12][13][14] cryogenic cooling, [15,16] RSC driving thermoelectricity, [17][18][19] atmospheric water harvesting, [20,21] personal thermal management [3,22,23] and wearable devices. [24][25][26] For building cooling, the pioneering reports by Goldstein et al. and Zhao et al. have demonstrated that building-integrated RSC modules can provide continuous day-and-night cooling and can potentially save 32%-45% of the electricity consumption for cooling in summer. [4,11] For photovoltaic cooling, selective photonic cooler can lower the temperature of solar panels by over 5.7 K and afford the greater cooling

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Bioinspired Radiative Cooling Structure with Randomly Stacked Fibers for Efficient All-Day Passive Cooling

Cited by 57 publications

References 43 publications

Ordered-Porous-Array Polymethyl Methacrylate Films for Radiative Cooling

Ordered-Porous-Array Polymethyl Methacrylate Films for Radiative Cooling

Hierarchical-Morphology Metal/Polymer Heterostructure for Scalable Multimodal Thermal Management

Micro‐Nano Porous Structure for Efficient Daytime Radiative Sky Cooling

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