Passive radiative cooling design with broadband optical thin-film filters

Keçebaş, Muhammed Ali; Mengüç, M. Pınar; Koşar, Ali; Şendur, Kürşat

doi:10.1016/j.jqsrt.2017.03.046

Cited by 179 publications

(97 citation statements)

References 27 publications

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“…The structure proposed in [88] presents a very low transmissivity in the shortwave wavelength, below 0.05, mainly because of the high absorptivity of Ge. Much higher reflectivity values, between 0.97 and 0.98, are measured when a metal reflector is combined with a thin film of alternating materials of high and low refractive index [70,86]. In [70], layers of SiO 2 and HfO 2 are used, while in [86], HfO 2 is replaced by TiO 2, as is shown in Figure 3a.…”

Section: Multilayer Planar Photonic Radiative Structuresmentioning

confidence: 98%

“…To achieve a high reflectivity in the shortwave, either a single Ag or Al mirror is used [39,41,84,87,95], or a structure of alternate layers of high and low refraction index materials [87], or a combination of a Ag or Al minor on the bottom of alternate high-low refractive index materials [70,85,86]. The specific composition of the reflective component of each structure is described in Table 1.…”

Section: Multilayer Planar Photonic Radiative Structuresmentioning

confidence: 99%

“…In [95], SiO 2 is combined with PPMA giving an average emissivity in the AW close to 0.72, while in [39], layers of Si and Si 3 N 4 are used and the spectral emissivity in the AW varied between 0.2 to 0.9. In [86,88], the emitting structures were composed by three different materials. In [86], alternating layers of TiO 2 , SiO 2 and Al 2 O 3 were proposed and the emissivity in the AW was between 0.7 and 0.8.…”

Section: Multilayer Planar Photonic Radiative Structuresmentioning

confidence: 99%

See 2 more Smart Citations

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

2018

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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.

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Section: Multilayer Planar Photonic Radiative Structuresmentioning

confidence: 98%

Section: Multilayer Planar Photonic Radiative Structuresmentioning

confidence: 99%

Section: Multilayer Planar Photonic Radiative Structuresmentioning

confidence: 99%

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

2018

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“…On average, a 37 • C temperature reduction below ambient was achieved. The final film-type structure [35] was constructed with layers using all the key elements from previous research [36]. This film was made up of multiple layers of SiO 2 and titanium dioxide (TiO 2 ) on an Al or Ag layer (Figure 2c), thereby consisting of low-and high-index materials to utilize their emission spectra and high absorption caused by the phonon-polariton resonance.…”

Section: Metamaterial-based Radiative Cooling Using a Film Structurementioning

confidence: 99%

“…In using polymers for radiative cooling, the polymer layer plays an important role in assisting the conventional reflection and emission layers. SiO2/TiO2 multi-layer on a metallic Al/Ag reflector [35], (d) VO2 with a dielectric spacer on Al [37], (e) PDMS/SiO2 on Ag [38], (f) PTFE/Ag on Si [39], and (g) SiO2/PMMA/SiO2 on Al [40] have been reported.…”

Section: Metamaterial-based Radiative Cooling Using a Film Structurementioning

confidence: 99%

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

et al. 2018

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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.

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Highly Efficient Polystyrene/Metal Oxide Fiber Composites for Passive Radiative Cooling

et al. 2021

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Passive radiative cooling has garnered significant attention in energy‐saving applications as it is an effective way to cool to temperatures below ambient without external energy input. Successful cooling performances can be achieved by carefully selecting metal oxides with narrow absorption bands that lie entirely within the atmospheric window of 8−13 μm, thereby allowing radiative transfer between terrestrial objects and outer space. Highly scalable, metal oxide‐doped fibers made from recyclable polystyrene herein are proposed and demonstrated. The material exhibits nearly 100% reflectivity in the visible and near‐infrared (IR) range, and under direct solar irradiation, the material can cool by up to 22.3 °C below the ambient temperature without energy input due to strong emissivity in the atmospheric window. This cooling persists despite nonideal atmospheric conditions and convective/conductive heat exchange. Microsized fiber‐based radiative cooling is reported for the first time. Unlike film‐based passive radiative cooling materials, fibers are relatively simple to manufacture, flexible, lightweight, and low in cost. Therefore, such a material may be suitable for large‐scale applications such as buildings to supplement air conditioning or as a wearable fabric to promote subambient cooling for the wearer.

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Passive radiative cooling design with broadband optical thin-film filters

Cited by 179 publications

References 27 publications

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

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

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

Highly Efficient Polystyrene/Metal Oxide Fiber Composites for Passive Radiative Cooling

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