scholarly journals Performance simulation of polymer-based nanoparticle and void dispersed photonic structures for radiative cooling

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jay Prakash Bijarniya ◽  
Jahar Sarkar ◽  
Pralay Maiti
Keyword(s):  
Fdtd Method ◽  
Solar Spectrum ◽  
Thermal Infrared ◽  
Performance Estimation ◽  
Radiative Cooling ◽  
Slab Thickness ◽  
Slight Variation ◽  
Performance Simulation ◽  
Atmospheric Window ◽  
Substrate Independent

AbstractPassive radiative cooling is an emerging field and needs further development of material. Hence, the computational approach needs to establish for effective metamaterial design before fabrication. The finite difference time domain (FDTD) method is a promising numerical strategy to study electromagnetic interaction with the material. Here, we simulate using the FDTD method and report the behavior of various nanoparticles (SiO2, TiO2, Si3N4) and void dispersed polymers for the solar and thermal infrared spectrums. We propose the algorithm to simulate the surface emissive properties of various material nanostructures in both solar and thermal infrared spectrums, followed by cooling performance estimation. It is indeed found out that staggered and randomly distributed nanoparticle reflects efficiently in the solar radiation spectrum, become highly reflective for thin slab and emits efficiently in the atmospheric window (8–13 µm) over the parallel arrangement with slight variation. Higher slab thickness and concentration yield better reflectivity in the solar spectrum. SiO2-nanopores in a polymer, Si3N4 and TiO2 with/without voids in polymer efficiently achieve above 97% reflection in the solar spectrum and exhibits substrate independent radiative cooling properties. SiO2 and polymer combination alone is unable to reflect as desired in the solar spectrum and need a highly reflective substrate like silver.

Hierarchical-morphology metafabric for scalable passive daytime radiative cooling

Science ◽  
2021 ◽  
pp. eabi5484
Author(s):  
Shaoning Zeng ◽  
Sijie Pian ◽  
Minyu Su ◽  
Zhuning Wang ◽  
Maoqi Wu ◽  
...  
Keyword(s):  
High Performance ◽  
Large Scale ◽  
Global Climate ◽  
Solar Spectrum ◽  
Radiative Cooling ◽  
Practical Application ◽  
Atmospheric Window ◽  
The Cost ◽  
Hierarchical Morphology ◽  
Cooling Ability

Incorporating passive radiative cooling structures into personal thermal management technologies could effectively defend human against the intensifying global climate change. We show that large scale woven metafabrics can provide high emissivity (94.5%) in the atmospheric window and reflectivity (92.4%) in the solar spectrum because the hierarchical-morphology design of the randomly dispersed scatterers throughout the metafabric. Through scalable industrial textile manufacturing routes, our metafabrics exhibit excellent mechanical strength, waterproofness, and breathability for commercial clothing while maintaining efficient radiative cooling ability. Practical application tests demonstrated the human body covered by our metafabric could be cooled down ~4.8°C lower than that covered by commercial cotton fabric. The cost-effectiveness and high-performance of our metafabrics present great advantages for intelligent garments, smart textiles, and passive radiative cooling applications.

scholarly journals Simple Double-Layer Coating for Efficient Daytime and Nighttime Radiative Cooling

Atmosphere ◽  
2021 ◽  
Vol 12 (9) ◽  
pp. 1198
Author(s):  
Mourad Benlattar ◽  
Issam Ibourk ◽  
Rahma Adhiri
Keyword(s):  
Double Layer ◽  
Large Scale ◽  
Outer Space ◽  
Solar Spectrum ◽  
Bottom Layer ◽  
Solar Irradiation ◽  
Radiative Cooling ◽  
Atmospheric Window ◽  
Thermal Emitters ◽  
Layer Coating

The passive radiative cooling approach refers to the physical process that pumps heat into outer space via the atmospheric window (8–13 μm) without energy input. The ability to continuously adjust the emissivity of thermal emitters in the sky window while maintaining high reflectivity in the solar spectrum remains a challenge. In order to achieve this task, a novel design referred to as double-layer nanoparticle-based coating is proposed. Our proposed emitter is appropriate for both high solar reflection and strong mid-infrared emissivity. The bottom and top layers are Al2O3 embedded with Ni nanoparticles and a super-hydrophilic TiO2-SiO2 layer. The bottom layer is designed to achieve high emissivity in “the atmospheric transparency window”. The top layer is designed to block solar illumination and to favor an enhanced cleanability of the coated design. Our double-layer coating as an optical solar reflector has excellent solar irradiation ( and is strongly emissive (0.97) across the “full sky window” at room temperature. Furthermore, a detailed numerical energy study has been performed, evaluating the temperature reduction and the radiative cooling performance under different conditions. The proposed simple coating can be used as an efficient radiative cooler on a large scale for energy conservation and thermoelectric devices.

scholarly journals Recent Progress in Daytime Radiative Cooling: Is It the Air Conditioner of the Future?

Buildings ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 168 ◽  
Author(s):  
Mattheos Santamouris ◽  
Jie Feng
Keyword(s):  
Thin Film ◽  
Thermal Performance ◽  
Recent Progress ◽  
Solar Spectrum ◽  
Radiative Cooling ◽  
The Sun ◽  
Air Conditioner ◽  
Photonic Structures ◽  
Atmospheric Window ◽  
Ambient Surface

Radiative cooling is a well-researched area. For many years, surfaces relying on radiative cooling failed to exhibit a sub-ambient surface temperature under the sun because of the limited reflectance in the solar spectrum and the reduced absorptivity in the atmospheric window. The recent impressive developments in photonic nanoscience permitted to produce photonic structures exhibiting surface temperatures much below the ambient temperature. This paper aims to present and analyze the main recent achievements concerning daytime radiative cooling technologies. While the conventional radiative systems are briefly presented, the emphasis is given on the various photonic radiative structures and mainly the planar thin film radiators, metamaterials, 2 and 3D photonic structures, polymeric photonic technologies, and passive radiators under the form of a paint. The composition of each structure, as well as its experimental or simulated thermal performance, is reported in detail. The main limitations and constraints of the photonic radiative systems, the proposed technological solutions, and the prospects are presented and discussed.

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.

Bio-skin inspired 3D porous cellulose/AlPO4 nano-laminated film with structure-enhanced selective emission for all-day non-power cooling

2021 ◽  
Author(s):  
Shuangjiang Feng ◽  
Yuming Zhou ◽  
Xi Chen ◽  
Shengnan Shi ◽  
Chenghuan Liu ◽  
...  
Keyword(s):  
Radiative Cooling ◽  
Preparation Technology ◽  
Cellulose Films ◽  
Highly Efficient ◽  
Atmospheric Window ◽  
Complex Preparation

Porous cellulose films have been reported as sustainable and highly-efficient non-power radiative cooling (PRC) materials but still challenged by their insufficient atmospheric window (AM) emissivity and complex preparation technology. Herein,...

scholarly journals Analysis of Sustainable Materials for Radiative Cooling Potential of Building Surfaces

2018 ◽  
Vol 10 (9) ◽  
pp. 3049 ◽  
Author(s):  
Roxana Family ◽  
M. Mengüç
Keyword(s):  
Heat Transfer ◽  
Emission Spectra ◽  
Spectral Emissivity ◽  
Volumetric Analysis ◽  
Solar Heating ◽  
Heat Transfer Analysis ◽  
Surface Phenomenon ◽  
Radiative Cooling ◽  
Atmospheric Window ◽  
Building Surfaces

The main goal of this paper is to explore the radiative cooling and solar heating potential of several materials for the built environment, based on their spectrally-selective properties. A material for solar heating, should have high spectral emissivity/absorptivity in the solar radiation band (within the wavelength range of 0.2–2 μm), and low emissivity/absorptivity at longer wavelengths. Radiative cooling applications require high spectral emissivity/absorptivity, within the atmospheric window band (8–13 μm), and a low emissivity/absorptivity in other bands. UV-Vis spectrophotometer and FTIR spectroscopy, are used to measure, the spectral absorption/emission spectra of six different types of materials. To evaluate the radiative cooling potential of the samples, the power of cooling is calculated. Heat transfer through most materials is not just a surface phenomenon, but it also needs a volumetric analysis. Therefore, a coupled radiation and conduction heat transfer analysis is used. Results are discussed for the selection of the best materials, for different applications on building surfaces.

scholarly journals Metamaterial-Based Radiative Cooling: Towards Energy-Free All-Day Cooling

Energies ◽  
2018 ◽  
Vol 12 (1) ◽  
pp. 89 ◽  
Author(s):  
Byoungsu Ko ◽  
Dasol Lee ◽  
Trevon Badloe ◽  
Junsuk Rho
Keyword(s):  
Near Infrared ◽  
Thermal Emission ◽  
Cooling System ◽  
Radiative Cooling ◽  
Future Perspectives ◽  
Direct Sunlight ◽  
Basic Principles ◽  
Atmospheric Window ◽  
Window Region ◽  
Reduce Energy Consumption

In the light of the ever increasing dangers of global warming, the efforts to reduce energy consumption by radiative cooling techniques have been designed, but are inefficient under strong sunlight during the daytime. With the advent of metamaterials and their selective control over optical properties, radiative cooling under direct sunlight is now possible. The key principles of metamaterial-based radiative cooling are: almost perfect reflection in the visible and near-infrared spectrum (0.3–3 µm) and high thermal emission in the infrared atmospheric window region (8–13 µm). Based on these two basic principles, studies have been conducted using various materials and structures to find the most efficient radiative cooling system. In this review, we analyze the materials and structures being used for radiative cooling, and suggest the future perspectives as a substitute in the current cooling industry.

Sign in / Sign up

Export Citation Format

Share Document