Browse
Submit Data
Databases
API
Help

Dataset Information

0 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Tunable daytime passive radiative cooling based on a broadband angle selective low-pass filter.

ABSTRACT: Passive daytime cooling could contribute to the reduction of our global energy consumption. It is capable of cooling materials down to below ambient temperatures without the necessity of any additional input energy. Yet, current devices and concepts all lack the possibility to switch the cooling properties on and off. Here, we introduce dynamic control for passive radiative cooling during daytime. Using an angle-selective solar filter on top of a nocturnal passive radiator allows tuning the surface temperature of the latter in a wide range by just tilting the filter from normal incidence up to around 23°. This angle-selective filter is based on optically engineered, one-dimensional photonic crystal structures. We use numerical simulations to investigate the feasibility of a switchable low-pass filter/emitter device.

SUBMITTER: Pech-May NW

PROVIDER: S-EPMC9419168 | biostudies-literature | 2020 Jan

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Publications

Tunable daytime passive radiative cooling based on a broadband angle selective low-pass filter.

Pech-May Nelson W NW Retsch Markus M

Nanoscale advances 20191104 1

Passive daytime cooling could contribute to the reduction of our global energy consumption. It is capable of cooling materials down to below ambient temperatures without the necessity of any additional input energy. Yet, current devices and concepts all lack the possibility to switch the cooling properties on and off. Here, we introduce dynamic control for passive radiative cooling during daytime. Using an angle-selective solar filter on top of a nocturnal passive radiator allows tuning the surf ...[more]

PMID: 36133993

Similar Datasets

Passive Daytime Radiative Cooling of Silica Aerogels.

Project description:Silica aerogels are one of the most widely used aerogels, exhibiting excellent thermal insulation performance and ultralow density. However, owing to their plenitude of Si-O-Si bonds, they possess high infrared emissivity in the range of 8-13 µm and are potentially robust passive radiative cooling (PRC) materials. In this study, the PRC behavior of traditional silica aerogels prepared from methyltrimethoxysilane (MTMS) and dimethyldimethoxysilane (DMDMS) in outdoor environments was investigated. The silica aerogels possessed low thermal conductivity of 0.035 W/m·K and showed excellent thermal insulation performance in room environments. However, sub-ambient cooling of 12 °C was observed on a clear night and sub-ambient cooling of up to 7.5 °C was achieved in the daytime, which indicated that in these cases the silica aerogel became a robust cooling material rather than a thermal insulator owing to its high IR emissivity of 0.932 and high solar reflectance of 0.924. In summary, this study shows the PRC performance of silica aerogels, and the findings guide the utilization of silica aerogels by considering their application environments for achieving optimal thermal management behavior.

| S-EPMC9919039 | biostudies-literature

Passive directional sub-ambient daytime radiative cooling.

Project description:Demonstrations of passive daytime radiative cooling have primarily relied on complex and costly spectrally selective nanophotonic structures with high emissivity in the transparent atmospheric spectral window and high reflectivity in the solar spectrum. Here, we show a directional approach to passive radiative cooling that exploits the angular confinement of solar irradiation in the sky to achieve sub-ambient cooling during the day regardless of the emitter properties in the solar spectrum. We experimentally demonstrate this approach using a setup comprising a polished aluminum disk that reflects direct solar irradiation and a white infrared-transparent polyethylene convection cover that minimizes diffuse solar irradiation. Measurements performed around solar noon show a minimum temperature of 6?°C below ambient temperature and maximum cooling power of 45 W?m-2. Our passive cooling approach, realized using commonly available low-cost materials, could improve the performance of existing cooling systems and enable next-generation thermal management and refrigeration solutions.

| S-EPMC6258698 | biostudies-other

A tandem radiative/evaporative cooler for weather-insensitive and high-performance daytime passive cooling.

Project description:Radiative cooling and evaporative cooling with low carbon footprint are regarded as promising passive cooling strategies. However, the intrinsic limits of continuous water supply with complex systems for evaporative cooling, and restricted cooling power as well as the strict requirement of weather conditions for radiative cooling, hinder the scale of their practical applications. Here, we propose a tandem passive cooler composed of bilayer polymer that enables dual-functional passive cooling of radiation and evaporation. Specifically, the high reflectivity to sunlight and mid-infrared emissivity of this polymer film allows excellent radiative cooling performance, and its good atmospheric water harvesting property of underlayer ensures self-supply of water and high evaporative cooling power. Consequently, this tandem passive cooler overcomes the fundamental difficulties of radiative cooling and evaporative cooling and shows the applicability under various conditions of weather/climate. It is expected that this design can expand the practical application domain of passive cooling.

| S-EPMC9374334 | biostudies-literature

Vapor condensation with daytime radiative cooling.

Project description:A radiative vapor condenser sheds heat in the form of infrared radiation and cools itself to below the ambient air temperature to produce liquid water from vapor. This effect has been known for centuries, and is exploited by some insects to survive in dry deserts. Humans have also been using radiative condensation for dew collection. However, all existing radiative vapor condensers must operate during the nighttime. Here, we develop daytime radiative condensers that continue to operate 24 h a day. These daytime radiative condensers can produce water from vapor under direct sunlight, without active consumption of energy. Combined with traditional passive cooling via convection and conduction, radiative cooling can substantially increase the performance of passive vapor condensation, which can be used for passive water extraction and purification technologies.

| S-EPMC8040807 | biostudies-literature

Aerogel-Functionalized Thermoplastic Polyurethane as Waterproof, Breathable Freestanding Films and Coatings for Passive Daytime Radiative Cooling.

Project description:Passive daytime radiative cooling (PDRC) is an emerging sustainable technology that can spontaneously radiate heat to outer space through an atmospheric transparency window to achieve self-cooling. PDRC has attracted considerable attention and shows great potential for personal thermal management (PTM). However, PDRC polymers are limited to polyethylene, polyvinylidene fluoride, and their derivatives. In this study, a series of polymer films based on thermoplastic polyurethane (TPU) and their composite films with silica aerogels (aerogel-functionalized TPU (AFTPU)) are prepared using a simple and scalable non-solvent-phase-separation strategy. The TPU and AFTPU films are freestanding, mechanically strong, show high solar reflection up to 94%, and emit strongly in the atmospheric transparency window, thereby achieving subambient cooling of 10.0 and 7.7 °C on a hot summer day for the TPU and AFTPU film (10 wt%), respectively. The AFTPU films can be used as waterproof and moisture permeable coatings for traditional textiles, such as cotton, polyester, and nylon, and the highest temperature drop of 17.6 °C is achieved with respect to pristine nylon fabric, in which both the cooling performance and waterproof properties are highly desirable for the PTM applications. This study opens up a promising route for designing common polymers for highly efficient PDRC.

| S-EPMC9284144 | biostudies-literature

Sustainable and Inexpensive Polydimethylsiloxane Sponges for Daytime Radiative Cooling.

Project description:Radiative cooling is an emerging cooling technology that can passively release heat to the environment. To obtain a subambient cooling effect during the daytime, chemically engineered structural materials are widely explored to simultaneously reject sunlight and preserve strong thermal emission. However, many previously reported fabrication processes involve hazardous chemicals, which can hinder a material's ability to be mass produced. In order to eliminate the hazardous chemicals used in the fabrication of previous works, this article reports a white polydimethylsiloxane (PDMS) sponge fabricated by a sustainable process using microsugar templates. By substituting the chemicals for sugar, the manufacturing procedure produces zero toxic waste and can also be endlessly recycled via methods widely used in the sugar industry. The obtained porous PDMS exhibits strong visible scattering and thermal emission, resulting in an efficient temperature reduction of 4.6 °C and cooling power of 43 W m-2 under direct solar irradiation. In addition, due to the air-filled voids within the PDMS sponge, its thermal conductivity remains low at 0.06 W (m K)-1 . This unique combination of radiative cooling and thermal insulation properties can efficiently suppress the heat exchange with the solar-heated rooftop or the environment, representing a promising future for new energy-efficient building envelope material.

| S-EPMC8655219 | biostudies-literature

An externally tunable bacterial band-pass filter.

Project description:The current paradigm for tuning synthetic biological systems is through re-engineering system components. Biological systems designed with the inherent ability to be tuned by external stimuli will be more versatile. We engineered Escherichia coli cells to behave as an externally tunable band-pass filter for enzyme activity and small molecules. The band's location can be positioned within a range of 4 orders of magnitude simply by the addition of compounds to the growth medium. Inclusion in the genetic network of an enzyme-substrate pair that functions as an attenuator is a generalizable strategy that enables this tunability. The genetic circuit enabled bacteria growth to be patterned in response to chemical gradients in nonintuitive ways and facilitated the isolation of engineered allosteric enzymes. The application of this strategy to other biological systems will increase their utility for biotechnological applications and their usefulness as a tool for gaining insight into nature's underlying design principles.

| S-EPMC2700907 | biostudies-literature

Phase-change materials reinforced intelligent paint for efficient daytime radiative cooling.

Project description:Passive cooling of buildings has become increasingly important for green and low-carbon development, especially in the near decade where daytime radiative cooling technology (DRCT) has drawn attention with big breakthroughs. However, irresistibly importing heat from sunlight and surroundings results in notable temperature rise, thus limiting the cooling effect. Here, we report a radiative paint with latent heat storage capacity to store imported heat by coupling randomly-distributed phase-change materials (PCMs) based microcapsules with acrylic resin to enhance cooling performance. The bifunctional paint shows good performance in selected-suitable phase transition temperature, high enthalpy, high reflectivity in the sunlight region and strong emissivity in the atmospheric window region. The temperature measurements demonstrate that the paint possesses enhanced cooling performance of temperature drop and time buffering effect compared with the pure radiative cooling paint. This work offers the potential to broaden the applications of PCMs and DRCT for energy saving and environment protection.

| S-EPMC9240859 | biostudies-literature

Biologically inspired flexible photonic films for efficient passive radiative cooling.

Project description: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-2 and 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.

| S-EPMC7334532 | biostudies-literature

Whitish daytime radiative cooling using diffuse reflection of non-resonant silica nanoshells.

Project description:Daytime radiative cooling offers efficient passive cooling of objects by tailoring their spectral responses, holding great promise for green photonics applications. A specular reflector has been utilized in cooling devices to minimize sunlight absorption, but such a glaring surface is visually less appealing, thus undesirable for public use. Here, by exploiting strong diffuse reflection of silica nanoshells in a polymer matrix, daytime radiative cooling below the ambient temperature is experimentally demonstrated, while showing whitish color under sunlight. The cooling device consists of a poly(methyl methacrylate) layer with randomly distributed silica nanoshells and a polydimethylsiloxane (PDMS) layer on an Ag mirror. The non-resonant nanoshells exhibit uniform diffuse reflection over the solar spectrum, while fully transparent for a selective thermal radiation from the underneath PDMS layer. In the temperature measurement under the sunlight irradiation, the device shows 2.3?°C cooler than the ambient, which is comparable to or even better than the conventional device without the nanoshells. Our approach provides a simple yet powerful nanophotonic structure for realizing a scalable and practical daytime radiative cooling device without a glaring reflective surface.

| S-EPMC7162956 | biostudies-literature

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

Tweets

OmicsDI Databases

PRIDE
PeptideAtlas
MassIVE
JPOST Repository
Physiome Model Repository

EGA
EVA
ENA
LINCS
PAXDB
Cell Collective

MetaboLights
Metabolomics Workbench
MetabolomeExpress
GNPS
BioModels
FAIRDOMHub

ArrayExpress
dbGaP
ExpressionAtlas
GEO
NODE

Information

Databases
Help
API
Contact us
Code on GitHub
Terms of use
Submit Data