KR102340400B1 - Colored radiative cooling device - Google Patents

Abstract

The present invention relates to a technology for providing a colored radiative cooling device performing radiative cooling while expressing various colors, which efficiently controls incident sunlight to reflect near-infrared rays, minimizes heat inflow caused by the absorption of visible light required for color realization, and absorbs and radiates infrared rays in an atmospheric window range to express the various colors. The colored radiative cooling device according to an embodiment of the present invention comprises: a color realization layer that reflects near-infrared rays of incident sunlight and absorbs a specific visible ray of the incident sunlight to realize at least one color; a wavelength-converting light absorbing and emitting layer positioned on the color realization layer and composed of a light emitting body that absorbs and emits ultraviolet rays and visible rays other than the absorbed specific ray of the incident sunlight to reduce heat inflow caused by the absorption of the incident sunlight; and a radiative cooling layer positioned under the color realization layer, absorbing and emitting long-wavelength infrared rays in a wavelength range corresponding to an atmospheric window, and increasing reflectivity of the near-infrared rays by reflecting the near-infrared rays.

Description

COLORED RADIATIVE COOLING DEVICE

The present invention relates to a color-type radiation cooling device, which efficiently controls incident sunlight to reflect near-infrared rays, minimizes heat inflow due to absorption of visible light required for color realization, and has a wavelength range of the sky window It relates to a technology to provide a color-type radiation cooling device that performs radiative cooling while expressing various colors as infrared rays are absorbed and emitted.

A passive radiative cooling device can be passively cooled by reflecting the wavelength (0.3-2.5㎛) corresponding to sunlight during the day and radiating radiant heat (8-13㎛) energy that can escape out of space.

On the other hand, the passive radiative heating element absorbs the wavelength (0.3-2.5㎛) corresponding to sunlight during the day and does not absorb the radiant heat (8-13㎛) energy that can escape out of space, so it is heated passively. can be

The efficiency of the passive cooling device can be confirmed by measuring the optical properties of the device itself.

For heat dissipation, it must be able to radiate heat into space as it has a high absorption or emissivity in the long-wavelength infrared region.

According to the Planck distribution, when the temperature is 300K, it has a condition for maximally dissipating heat in the wavelength range of 6-20 μm. In the case of the Earth, the sky window region of the atmosphere is about 8-13 μm, so in order to maximize the heat dissipation capability of the passive cooling element, the absorption or emissivity in the 8-13 μm region should be the maximum.

Infrared radiation in the atmospheric window wavelength range plays a key role in achieving radiative cooling by substantial heat release. If the wavelength range reflects 100% of the incident sunlight (emitted from the sun), and can radiate 100% of long-wavelength infrared rays in the 8㎛-13㎛ region, which is the window section of the atmosphere, 300K when ambient temperature is the cooling performance of 158W / m ² of this can be implemented with no energy consumption.

If 95% of sunlight is reflected and 90% or more of long-wavelength infrared rays in the 8㎛-13㎛ area are radiated to the outside, the cooling performance of ^{100W/m 2 is achieved during the day (ie, there is light absorption by the sun) when the ambient temperature is 300K.} And at night when there is no light absorption by the sun, a ^{cooling performance of 120W/m 2} can be realized.

In order to be used as a passive radiation cooling material, it must have high transmittance or high reflectance to light in the UV-vis-NIR wavelength range, which is incident sunlight, and must not absorb incident sunlight. It must have high absorption (emissivity) for long-wavelength infrared rays in the region, and must have high durability in outdoor conditions. It should be possible to mold to

Polymer materials generally have high absorption (emissivity) with respect to long-wavelength infrared rays, but due to the characteristics of the material, they are easily deteriorated by ultraviolet rays and moisture when left outdoors, resulting in a short lifespan.

In addition, since the thick polymer material is a broadband emitter with high emissivity for all infrared wavelength bands, radiative cooling performance may be lower than that of a selective emitter with high emissivity in the sky window. .

In the case of using a multi-layer thin film made of an inorganic material or a ceramic material, the number of layers must be large in order to increase the emissivity in the entire window in the atmosphere, which increases the absorption of sunlight, making it difficult to achieve high-efficiency radiation cooling performance.

In addition, it is difficult to apply radiative cooling to real life due to long-term stability problems (oxidation problem) and cost problems of silver and aluminum in the radiation cooling device including a lower metal reflective layer such as silver and aluminum, and these metal materials mainly use specular reflection This can cause eye strain and light bleed.

The material of the existing paint contains a high content of binder and _{uses TiO 2} nano or micro particles. Due to _{the relatively low band gap energy of TiO 2} , it absorbs sunlight in the UV-near visible region, and Absorption in the NIR region is high due to the high extinction coefficient in the NIR region.

In addition, since these existing paint materials are not composed of a material having a high extinction coefficient in the window of the atmosphere, there is a problem that the emissivity in the window of the atmosphere and the emissivity by angle are not high.

For example, the inside temperature of a black car that absorbs light well in broad daylight rises easily, but the temperature rises relatively slowly in the case of a white car that reflects light well without absorbing it.

If the surface of the car can reflect all light in the wavelength range of ultraviolet, visible, and near-infrared rays, it is possible to block the inflow of thermal energy due to solar radiation.

In addition, when a material has a color, the material has a specific absorption (reflection) value in the visible light band.

For example, if the material is red, the material may reflect light at a wavelength of 650 nm to emit red, or because the bandgap energy of the material is near a wavelength of 650 nm, it may absorb light to represent red.

Since absorption of light in the visible ray band is inevitable for color realization, when viewed from the perspective of radiative cooling, it can be linked to a reduction in total radiative cooling power.

However, until now, most radiation cooling materials and devices are white or silver, so radiation cooling materials and devices used in various places such as building materials, automobiles, and ships do not take into account the aesthetic point of view of consumers.

Accordingly, there is a need to develop a radiation cooling material and device having excellent radiation cooling performance while implementing various colors in consideration of the aesthetic point of view of consumers.

Korean Patent Laid-Open Patent No. 10-2021-000278, "Color-type radiation cooling device" Korean Patent No. 10-2154072, "Coolant capable of realizing color in radiative cooling and color realization method using the same" Korea Patent No. 10-2225793, "Color-type radiation cooling device using nanoparticles" Korean Patent No. 10-2140669, "Passive Radiation Cooling Structure"

The present invention efficiently controls incident sunlight to minimize heat inflow based on visible light of the sunlight spectrum required for color realization, and performs radiative cooling while expressing various colors as infrared rays in the wavelength range of the atmospheric window are absorbed and emitted. An object of the present invention is to provide a color-type radiant cooling element.

The present invention absorbs and emits light incident through the wavelength conversion absorption light emitting layer, and the material forming the wavelength conversion absorption light emitting layer emits a portion of the heat for the incident light in the form of photons, thereby minimizing the inflow of heat. It aims to provide a cooling element.

An object of the present invention is to provide a color-type radiation cooling device that has high reflectance in the near-infrared region with respect to incident sunlight, has a vivid color, and minimizes heat inflow through wavelength conversion absorption and emission using phosphor particles. .

In the present invention, the lower radiation cooling layer reflects near-infrared rays, the color realization layer in the middle part realizes color while maintaining high near-infrared reflection, and the upper part absorbs the ultraviolet and visible light to be absorbed by the color realization layer first. And an object of the present invention is to provide a color-type radiation cooling device that realizes a vivid color through a wavelength conversion absorption emission layer that minimizes heat inflow by re-emitting.

An object of the present invention is to provide a color-type radiation cooling device capable of realizing a vivid color in consideration of the user's aesthetic point of view.

The present invention cools the ambient temperature of a radiation cooling device without energy consumption even during day time when sunlight is shining or night time when sunlight is not shining. An object of the present invention is to provide a color-type radiation cooling device that can perform a cooling function without energy consumption.

An object of the present invention is to improve the energy efficiency of a cooling system by applying a color radiation cooling element to a cooling system.

The present invention provides a rigid or flexible color type radiation cooling device by sequentially forming a radiation cooling layer, a color realizing layer, and a wavelength conversion absorption light emitting layer on a rigid or flexible substrate aim to do

A color-type radiation cooling device according to an embodiment of the present invention is located on the color realization layer, which reflects the near-infrared rays of the incident sunlight and absorbs specific visible rays of the incident sunlight to realize at least one color, It is formed as a light emitting body that absorbs and emits the remaining visible light other than the ultraviolet of the incident sunlight and the absorbed specific visible light to reduce the heat inflow according to the absorption of the incident sunlight. , a radiation cooling layer that absorbs and emits long-wavelength infrared rays in a wavelength range corresponding to a sky window, and increases the reflectance of the near-infrared rays by reflecting the near-infrared rays.

The radiation cooling layer may be formed in any one of a single metal thin film structure, a multilayer thin film structure, a particle dispersion structure in a polymer matrix, a polymer pore structure, and a binder polymer structure.

The single metal thin film structure includes a metal solar reflective layer that reflects the near-infrared light based on a metal material, and the multi-layered thin-film structure includes any one of a polymer material and an inorganic material that absorbs and emits the long-wavelength infrared ray on the metal solar reflective layer One material or a mixed material in which at least one material is mixed is formed as at least one layer, and the particle dispersion structure in the polymer matrix is nano or inorganic material in the polymer matrix based on the polymer material on the metal solar reflective layer The micro particles may be dispersed and formed into at least one layer.

The polymer pore structure is formed to include a polymer material that absorbs and emits the long-wavelength infrared light and an air gap, and scatters and scatters the incident sunlight based on a refractive index difference between the polymer material and the air gap It is formed of at least one layer that reflects and reflects the near-infrared rays, the binder polymer structure having a first refractive index with respect to the near-infrared rays, a binder material absorbing and emitting the long-wavelength infrared rays, and a second refractive index with respect to the near-infrared rays, , It may be formed of at least one layer that reflects the near-infrared rays based on the difference in refractive index between the inorganic nano or micro-particles that absorb and emit the long-wavelength infrared rays and an air gap having a third refractive index with respect to the near-infrared rays. .

The polymer material is DPHA (DiPentaerythritol HexaAcrylate), PDMS (polydimethylsiloane), ETFE (Ethylene Tetra fluoro Ethylene), PUA (poly urethane acrylate), PS (polystyrene), PET (polyethylene terephthalate), PE (polyethylene), PC (polycarbonate) , PVDF (Polyvinylidene fluoride), PCTFE (Polychlorotrifluoroethylene), and may include at least one polymer material of polyethylene oxide (Polyethylene oxide).

The inorganic material is SiO ₂ , Si ₃ N ₄ , Al ₂ O ₃ , Ta ₂ O ₅ , c-BN, CaSO ₄ , MgHPO ₄ , ZrO ₂ , _{BaSO 4} , CaCO ₃ , AlN, AlPO ₄ , Y ₂ O ₃ of It may include at least one inorganic substance.

The binder material is DPHA (DiPentaerythritol HexaAcrylate), PDMS (polydimethylsiloane), ETFE (Ethylene Tetra fluoro Ethylene), PUA (poly urethane acrylate), PS (polystyrene), PET (polyethylene terephthalate), PE (polyethylene), PC (polycarbonate) , PVDF (Polyvinylidene fluoride), PCTFE (Polychlorotrifluoroethylene), polyethylene oxide (Polyethylene oxide), acrylic (Acrylic)-based polymer, polyester (Polyester)-based polymer and urethane (ethance) may include at least one binder material of the polymer have.

The metal material is silver (Ag), aluminum (Al), gold (Au), copper (cu), titanium (Ti), chromium (Cr), manganese (Mn), iron (Fe), platinum (Pt), lithium It may include at least one metal material selected from (Li) and sodium (Na) or an alloy material in which at least two are combined.

The light-emitting body may be formed of any one of a perovskite material and a chalcogenide-based material.

In the light-emitting body, any one of inorganic materials and polymer materials may be coated on a shell of particles based on any one of the perovskite material and the chalcogenide-based material.

The polymer material is DPHA (DiPentaerythritol HexaAcrylate), PDMS (polydimethylsiloane), ETFE (Ethylene Tetra fluoro Ethylene), PUA (poly urethane acrylate), PS (polystyrene), PET (polyethylene terephthalate), PE (polyethylene), PC (polycarbonate) , PVDF (Polyvinylidene fluoride), PCTFE (Polychlorotrifluoroethylene) and polyethylene oxide (Polyethylene oxide) containing at least one polymer material, the inorganic material is SiO ₂ , Si ₃ N ₄ , Al ₂ O ₃ , Ta ₂ O ₅ , c _{-BN, CaSO 4, MgHPO 4,} ZrO 2, BaSO 4, CaCO 3, AlN, AlPO 4, Y may include at least one inorganic substance of the ₂ O _3.

As the wavelength conversion absorption light emitting layer emits a color similar to the at least one color implemented based on the light emitting body, the color realization layer and an absorption section in the solar spectrum may overlap.

The radiation cooling layer is formed using at least one of a polymer material, a binder material, a metal material, an inorganic material, and nano or micro particles of an inorganic material, and the wavelength corresponding to the sky window of the at least one material As the at least one material is combined so that the emissivity for the long-wavelength infrared ray is complementary to each other in the range, the emissivity for the long-wavelength infrared ray may be increased.

The color realization layer, the wavelength conversion absorption light emitting layer, and the radiation cooling layer may be formed by drop casting, spin coating, bar coating, spray coating, or blade coating. , it can be formed by coating on various surfaces through at least one solution process of dying (dyeing) and brushing (brushing).

The various surfaces may include at least one of a wood surface, a glass surface, a metal substrate surface, a plastic surface, and a cloth surface.

The present invention efficiently controls incident sunlight to minimize heat inflow based on visible light of the sunlight spectrum required for color realization, and performs radiative cooling while expressing various colors as infrared rays in the wavelength range of the atmospheric window are absorbed and emitted. It is possible to provide a color-type radiant cooling element.

The present invention absorbs and emits light incident through the wavelength conversion absorption light emitting layer, and the material forming the wavelength conversion absorption light emitting layer emits a portion of the heat for the incident light in the form of photons, thereby minimizing the inflow of heat. A cooling element may be provided.

The present invention can provide a color-type radiation cooling device that has high reflectance in the near-infrared region with respect to incident sunlight, has a vivid color, and minimizes heat inflow through wavelength conversion absorption and emission using phosphor particles.

In the present invention, the lower radiation cooling layer reflects near-infrared rays, the color realization layer in the middle part realizes color while maintaining high near-infrared reflection, and the upper part absorbs the ultraviolet and visible light to be absorbed by the color realization layer first. And it is possible to provide a color-type radiation cooling device that realizes a vivid color through a wavelength conversion absorption and emission layer that minimizes heat inflow by re-emitting.

The present invention can provide a color-type radiation cooling device capable of realizing a vivid color in consideration of the user's aesthetic point of view.

The present invention cools the ambient temperature of a radiation cooling device without energy consumption even during day time when sunlight is shining or night time when sunlight is not shining. It is possible to provide a color-type radiation cooling device that can perform a cooling function without energy consumption.

The present invention can improve the energy efficiency of a cooling system by applying a color radiant cooling element to the cooling system.

The present invention provides a rigid or flexible color type radiation cooling device by sequentially forming a radiation cooling layer, a color realizing layer, and a wavelength conversion absorption light emitting layer on a rigid or flexible substrate can do.

1 is a view for explaining a color-type radiation cooling device according to an embodiment of the present invention.
2A to 2E are views for explaining a radiation cooling layer of a color-type radiation cooling device according to an embodiment of the present invention.
3 is a view for explaining optical characteristics related to a ratio obtained by dividing an extinction coefficient for each wavelength by a refractive index in relation to a radiation cooling layer of a color radiation cooling device according to an embodiment of the present invention.
4A to 4C are views for explaining various images related to the radiation cooling layer of the color-type radiation cooling device according to an embodiment of the present invention.
5A and 5B are diagrams for explaining optical characteristics and average emissivity for each angle within a window of the atmosphere in relation to a radiation cooling layer of a color-type radiation cooling device according to an embodiment of the present invention.
6A and 6B are views for explaining optical characteristics of a material forming a wavelength conversion absorption light emitting layer of a color radiation cooling device according to an embodiment of the present invention.
6C is a view for explaining the color realization characteristics of the material forming the wavelength conversion absorption light emitting layer of the color-type radiation cooling device according to an embodiment of the present invention.
7A to 7C are views for explaining an implementation image of a color-type radiation cooling device and optical characteristics of a color-type radiation cooling device according to an embodiment of the present invention.
8A and 8B are diagrams illustrating an experimental environment using a color-type radiation cooling device according to an embodiment of the present invention and radiative cooling performance measured in the experimental environment.

Hereinafter, various embodiments of the present document will be described with reference to the accompanying drawings.

Examples and terms used therein are not intended to limit the technology described in this document to a specific embodiment, but it should be understood to include various modifications, equivalents, and/or substitutions of the embodiments.

In the following, when it is determined that a detailed description of a known function or configuration related to various embodiments may unnecessarily obscure the gist of the present invention, a detailed description thereof will be omitted.

In addition, the terms to be described later are terms defined in consideration of functions in various embodiments, which may vary according to intentions or customs of users and operators. Therefore, the definition should be made based on the content throughout this specification.

In connection with the description of the drawings, like reference numerals may be used for like components.

The singular expression may include the plural expression unless the context clearly dictates otherwise.

In this document, expressions such as “A or B” or “at least one of A and/or B” may include all possible combinations of items listed together.

Expressions such as "first," "second," "first," or "second," can modify the corresponding elements regardless of order or importance, and to distinguish one element from another element. It is used only and does not limit the corresponding components.

When an (eg, first) component is referred to as being “connected (functionally or communicatively)” or “connected” to another (eg, second) component, that component is It may be directly connected to the component or may be connected through another component (eg, a third component).

As used herein, "configured to (or configured to)" according to the context, for example, hardware or software "suitable for," "having the ability to," "modified to ," "made to," "capable of," or "designed to" may be used interchangeably.

In some circumstances, the expression “a device configured to” may mean that the device is “capable of” with other devices or parts.

For example, the phrase "a processor configured (or configured to perform) A, B, and C" refers to a dedicated processor (eg, an embedded processor) for performing the corresponding operations, or by executing one or more software programs stored in a memory device. , may refer to a general-purpose processor (eg, a CPU or an application processor) capable of performing corresponding operations.

Also, the term 'or' means 'inclusive or' rather than 'exclusive or'.

That is, unless stated otherwise or clear from context, the expression 'x employs a or b' means any one of natural inclusive permutations.

Terms such as '.. unit' and '.. group' used below mean a unit that processes at least one function or operation, which may be implemented as hardware or software, or a combination of hardware and software.

1 is a view for explaining a color-type radiation cooling device according to an embodiment of the present invention.

1 illustrates the components of a color-type radiation cooling device according to an embodiment of the present invention.

Referring to FIG. 1 , the color radiation cooling device 100 according to an embodiment of the present invention includes a radiation cooling layer 110 , a color realization layer 120 , and a wavelength conversion absorption light emitting layer 130 .

For example, the color-type radiation cooling device 100 has a high reflectivity with respect to light in the near-infrared region with respect to incident sunlight, a vivid color is realized, and heat inflow through the phosphor particles can be minimized.

For example, the color-type radiation cooling device 100 includes a radiation cooling layer 110 at a lower portion, a color realization layer 120 at a middle portion, and a wavelength conversion absorption light-emitting layer 130 at an upper portion.

According to an embodiment of the present invention, the radiation cooling layer 110 performs near-infrared reflection, and the color realization layer 120 maintains high near-infrared reflection while realizing vivid colors.

In addition, as the wavelength conversion absorbing and emitting layer 130 having a color similar to that of the color realizing layer 120 is located above the color realizing layer 120 , the color realizing layer 120 absorbs light in the ultraviolet and visible ray regions. It absorbs first and minimizes heat inflow through re-discharge.

In addition, since the wavelength conversion absorption and emission layer 130 does not occupy a large portion of color implementation, it can support the implementation of vivid colors of the color implementation layer 120 .

That is, the color-type radiation cooling device 100 is a radiation cooling device having a high reflectivity with respect to ultraviolet, visible, and near-infrared rays included in incident sunlight. Radiative cooling can be performed while expressing various colors as infrared rays in the wavelength range of the atmospheric window are absorbed and emitted while minimizing the heat inflow based on visible light.

According to an embodiment of the present invention, the radiation cooling layer 110 is located under the color realization layer 120, absorbs and emits long-wavelength infrared rays in a wavelength range corresponding to the sky window, and reflects near-infrared rays. Accordingly, it is possible to increase the reflectance of near-infrared rays.

That is, the radiation cooling layer 110 reflects the near-infrared rays of the incident sunlight that the color realization layer 120 does not reflect in the lower part of the color realization layer 120 .

For example, the radiation cooling layer 110 may increase the reflectivity of the near-infrared rays of incident sunlight by specularly reflecting the near-infrared rays like a mirror or by diffusely reflecting due to a difference in refractive index.

As an example, the radiation cooling layer 110 may reflect near-infrared rays based on a metallic material or scatter and reflect near-infrared rays based on a difference in refractive index between nano or microparticles of a polymer material, a binder material, an inorganic material, and an air gap. have.

For example, as the refractive index difference increases, the reflectance for near-infrared rays may also increase.

According to an embodiment of the present invention, the radiation cooling layer 110 may be formed of any one of a single metal thin film structure, a multilayer thin film structure, a particle dispersion structure in a polymer matrix, a polymer pore structure, and a binder polymer structure.

Here, the formation structure of the radiation cooling layer 110 will be described supplementally with reference to FIGS. 2A to 2E .

According to an embodiment of the present invention, the radiation cooling layer 110 is formed using at least one of a polymer material, a binder material, a metal material, an inorganic material, and at least one of inorganic and inorganic nano or micro particles, and the window of the atmosphere of the at least one material. As at least one material is combined so that the emissivity of long-wavelength infrared rays in a wavelength range corresponding to (sky window) is mutually complementary, the emissivity of long-wavelength infrared rays may be increased.

For example, in the radiation cooling layer 110 , nano or micro particles and a polymer material have at least one extinction coefficient peak in a wavelength range corresponding to the window of the atmosphere, so that the emissivity within the window of the atmosphere is high.

That is, the material forming the radiation cooling layer 110 can provide all high emissivity within the wavelength range corresponding to the window of the atmosphere as materials having high emissivity for each wavelength within the wavelength range corresponding to the window of the atmosphere are combined. have.

For example, the polymer material is DPHA (DiPentaerythritol HexaAcrylate), PDMS (polydimethylsiloane), ETFE (Ethylene Tetra fluoro Ethylene), PUA (poly urethane acrylate), PS (polystyrene), PET (polyethylene terephthalate), PE (polyethylene), PC (polycarbonate), PVDF (Polyvinylidene fluoride), PCTFE (Polychlorotrifluoroethylene), and may include at least one polymer material of polyethylene oxide (Polyethylene oxide).

For example, the inorganic material is SiO ₂ , Si ₃ N ₄ , Al ₂ O ₃ , Ta ₂ O ₅ , c-BN, CaSO ₄ , MgHPO ₄ , ZrO ₂ , _{BaSO 4} , CaCO ₃ , AlN, AlPO ₄ , Y ₂ O It may include at least one inorganic substance among _3.

Meanwhile, the binder material is DPHA (DiPentaerythritol HexaAcrylate), PDMS (polydimethylsiloane), ETFE (Ethylene Tetra fluoro Ethylene), PUA (poly urethane acrylate), PS (polystyrene), PET (polyethylene terephthalate), PE (polyethylene), PC (polycarbonate) ), PVDF (Polyvinylidene fluoride), PCTFE (Polychlorotrifluoroethylene), polyethylene oxide (Polyethylene oxide), acrylic (Acrylic)-based polymer, polyester (Polyester)-based polymer and urethane (ethance) containing at least one binder material of the polymer can

According to an embodiment of the present invention, the color realization layer 120 may realize at least one color by absorbing a specific visible ray of the incident sunlight while reflecting the near-infrared rays of the incident sunlight.

That is, the color realization layer 120 may absorb only a specific visible light that is not absorbed by the wavelength conversion absorption light emitting layer 130 to implement a color according to the specific visible light and the material forming the color realizing layer 120 .

For example, commercial color paint may be used for the color realization layer 120 to implement various colors.

In addition, the color realization layer 120 prepares a solution by dissolving or dispersing a colored material in water, ethanol, acetone, PGMEA, PGME, Ethyl acetate, MEK, NMP, and then, through a solution process, the radiation cooling layer 110 ) can be formed on the

In other words, the color realization layer 120 does not absorb ultraviolet light as the wavelength conversion absorption light emitting layer 130 absorbs the remaining visible light other than the ultraviolet light and the specific visible light, and a specific visible light corresponding to the visible light for realizing the color. Since it does not absorb visible light other than light, heat input can be minimized.

According to an embodiment of the present invention, the wavelength conversion absorption light emitting layer 130 is positioned on the color realization layer 120 and is formed as a light emitting body that absorbs and emits the remaining visible rays other than the ultraviolet rays of the incident sunlight and the absorbed specific visible rays. It is possible to reduce heat inflow due to absorption of sunlight.

For example, the light-emitting body may be formed of any one of a perovskite material and a chalcogenide-based material.

For example, the perovskite material has the formula ABX ₃ , A includes any one of Cs, Sn, Bi, and methyl ammonium (Methyl Ammonium), and B is Fe, Co, Ni, Cu , Sn, Pb, Bi, Ge, containing any one of Ti and Zn metal material, X contains any one of Cl, Br, and I,

The chalcogenide-based material may be referred to as a chalcogenide compound.

Chalcogen means oxygen (O), sulfur (S), selenium (Se), and tellurium (Te) group 16 non-metal elements, which can make a 1:1 compound with alkaline earth metals, It can also react with the transition metal to provide a transition metal-chalcogenide composed of at least one chalcogen element and one or more positively charged elements.

Among these transition metal-chalcogenides, molybdenum chalcogenide in which molybdenum as a transition metal is combined with chalcogen is a compound obtained by combining molybdenum with sulfur (S), selenium (Se), and tellurium (Te), in detail MoS ₂ , MoSe ₂ , and MoTe ₂ are representative compounds.

A zinc chalcogenide is a compound comprising zinc metal and a chalcogen element (eg, selenium, tellurium, sulfur, or a combination thereof), wherein the zinc chalcogenide is ZnSe, ZnTeSe, ZnSeS, ZnS, ZnSTe, or combinations thereof may be included.

Metal chalcogen compounds are MoS2, MoSe2, WS2, WSe2, WTe2, MoTe ₂ , SnS ₂ , SnSe ₂ , ZrS ₂ , ZrSe ₂ , HfS ₂ , HfSe ₂ , NbSe ₂ , ReSe ₂ , BeS, MgS, CaS, SrS, At least one of BaS, NiS, ZnS, CdS, InS, BeSe, MgSe, CaSe, SrSe, BaSe, NiSe, ZnSe, CdSe, InSe, BeTe, MgTe, CaTe, SrTe, BaTe, NiTe, ZnTe, CdTe, and InTe may include

For example, in wavelength conversion absorption light emission, a material absorbs light with energy higher than the bandgap energy, and electrons are transferred from the valence band to the conduction band, and these electrons are transferred to the conduction band due to the change in the wave vector This includes a down-conversion phenomenon in which electrons present in the conduction band meet with holes in the valence band after moving through the valence band, and light equal to the energy difference between the valence band and conduction band escapes through radiative recombination.

In addition, wavelength conversion absorption light emission is caused by a specific electron (orbital) structure, and in the case of a material having a large amount of degenerate energy state inside the material, the electron transitions from the valence band to the degenerate energy state through absorption of a small amount of energy. The electrons transition back to a degenerate energy state with high energy through additional light absorption.

The electrons that have high energy following this repetitive process have a higher energy than the energy of the injected light. Including an up-conversion phenomenon that emits

Therefore, the present invention absorbs and emits light incident through the wavelength conversion absorption light emitting layer to minimize the inflow of heat as a material forming the wavelength conversion absorption light emitting layer emits a portion of the heat for the incident light in the form of photons. A type radiant cooling element may be provided.

The light-emitting body according to an embodiment of the present invention is a material of any one of inorganic materials and polymer materials in a shell of particles based on any one of a perovskite material and a chalcogenide-based material. This can be coated.

As an example, the wavelength conversion absorption light emitting layer 130 emits a color similar to at least one color implemented by the color realization layer 120 based on the light emitting body, so that the color realization layer 120 and the absorption section in the sunlight spectrum are may be duplicated.

That is, the wavelength conversion absorption light emitting layer 130 absorbs both a specific visible light and the remaining visible light, but sends only a specific visible light to the color realization layer 120 , and minimizes heat inflow by emitting the remaining visible light.

For example, in the wavelength conversion absorption light emitting layer 130, a powder of any one of a perovskite material, a chalcogenide material, and a commercially available phosphor is dissolved in water, ethanol, acetone, PGMEA, PGME, Ethyl acetate, MEK and NMP, or After dispersing to prepare a solution, it may be formed on the color realization layer 120 through a solution process.

According to an embodiment of the present invention, the radiation cooling layer 110 , the color realization layer 120 , and the wavelength conversion absorption light emitting layer 130 may be formed by drop casting, spin coating, or bar coating. , spray coating, blade coating, dyeing, and brushing may be formed by coating on various surfaces through at least one solution process.

For example, the various surfaces may include at least one of a wood surface, a glass surface, a metal substrate surface, a plastic surface, and a cloth surface.

That is, the color radiation cooling element 100 may be formed on various surfaces such as wood, plastic, and metal, and the various surfaces may have a curved surface or a patterned structure by bending.

Accordingly, the present invention provides a rigid or flexible color radiation cooling device by sequentially forming a radiation cooling layer, a color realizing layer, and a wavelength conversion absorption light emitting layer on a rigid or flexible substrate. can provide

About 90% of the color implemented by the color radiation cooling device 100 may be implemented by the color realization layer 120 , and the wavelength conversion absorption light emitting layer 130 may implement about 10% together.

On the other hand, in the case of a material capable of a solution process for forming the radiation cooling layer 110 , the color realization layer 120 , and the wavelength conversion absorption light emitting layer 130 , additives for extending the life of the material or improving physical properties may also be used.

Therefore, in the present invention, the lower radiation cooling layer reflects near-infrared rays, the color realization layer in the middle part realizes color while maintaining high near-infrared reflection, and the color realization layer absorbs the light in the ultraviolet and visible region from the upper part. First, it is possible to provide a color-type radiation cooling device that realizes a vivid color through a wavelength conversion absorption-emitting layer that minimizes heat inflow by absorbing and re-emitting it.

2A to 2E are views for explaining a radiation cooling layer of a color-type radiation cooling device according to an embodiment of the present invention.

2A illustrates a structure in which a radiation cooling layer of a color radiation cooling device according to an embodiment of the present invention is formed in a single metal thin film structure.

Referring to FIG. 2A , the radiation cooling layer 200 according to an embodiment of the present invention is formed of a metallic solar light reflecting layer that reflects near infrared rays based on a metallic material. That is, the radiation cooling layer 200 includes a metal solar reflection layer.

For example, the metal material is silver (Ag), aluminum (Al), gold (Au), copper (cu), titanium (Ti), chromium (Cr), manganese (Mn), iron (Fe), platinum (Pt) , at least one metal material selected from lithium (Li) and sodium (Na), or may include any one material of an alloy material in which at least two are combined.

In other words, the radiation cooling layer 200 provides an effect of enhancing the reflectivity of the near-infrared rays by additionally reflecting the near-infrared rays not reflected by the color realization layer as they specularly reflect the near-infrared rays of incident sunlight based on the metal material.

2B illustrates a case in which the radiation cooling layer 210 according to an embodiment of the present invention is formed in a multi-layered thin film structure.

Referring to FIG. 2B , the radiation cooling layer 210 according to an embodiment of the present invention is made of any one of a polymer material and an inorganic material or at least one material that absorbs and emits long-wavelength infrared rays on the metal solar reflection layer 211 . A mixed material in which the materials are mixed is formed into at least one layer. Here, at least one layer may be referred to as a selective emission layer 212 .

Specifically, the radiation cooling layer 210 has a solar light reflective layer 211 formed of a metal material disposed thereunder, and at least one inorganic material and a polymer material having a high emissivity in the window of the atmosphere are selected, and at least one selected material is It is formed by deposition or coating with at least one layer.

2C illustrates a case in which the radiation cooling layer 220 according to an embodiment of the present invention is formed in a particle-dispersed structure in a polymer matrix.

Referring to FIG. 2C , in the radiation cooling layer 220 according to an embodiment of the present invention, inorganic nanoparticles or micro particles 223 in a polymer matrix 222 based on a polymer material are formed on the metal solar light reflective layer 221 . It is dispersed and formed into at least one layer. Here, at least one layer may be referred to as a selective emission layer.

Specifically, the radiation cooling layer 220 has a solar reflective layer 221 formed of a metallic material disposed thereunder, and an inorganic material in a polymer matrix 222 having a high emissivity in the window of the atmosphere on the solar reflective layer 221 . of nano or micro particles 223 may be mixed and dispersed to form a selective emission layer.

According to an embodiment of the present invention, the radiation cooling layer 200 , the radiation cooling layer 210 , and the radiation cooling layer 220 may be viewed as a structure that increases the reflection of sunlight through specular reflection like a mirror based on a metal material.

2D illustrates a case in which the radiation cooling layer 230 according to an embodiment of the present invention is formed in a polymer pore structure.

Referring to FIG. 2D , the radiation cooling layer 230 according to an embodiment of the present invention has a polymer material 232 absorbing and emitting long-wavelength infrared rays on the solar reflection layer 231 formed of a metal material, and pores 233 . ), an optional radiation layer is formed to include. Here, the sunlight reflective layer 231 may be selectively excluded.

That is, the radiation cooling layer 230 may provide a near-infrared reflection function of the solar light reflection layer 231 in the selective emission layer.

However, when the sunlight reflective layer 231 is present, the reflectance for near-infrared rays may be increased.

The selective emission layer according to an embodiment of the present invention may be formed of at least one layer that reflects near-infrared rays by scattering and reflecting incident sunlight based on a difference in refractive index between the polymer material 232 and the pores 233 .

2E illustrates a case in which the radiation cooling layer 240 is formed of a binder polymer structure according to an embodiment of the present invention.

Referring to FIG. 2E , the radiation cooling layer 240 according to an embodiment of the present invention is a binder material 242 that absorbs and emits long-wavelength infrared rays on the solar reflective layer 241 formed of a metal material, and an inorganic nano material. Alternatively, an optional emissive layer is formed to include micro particles 243 and voids 243 . Here, the sunlight reflective layer 231 may be selectively excluded.

That is, the radiation cooling layer 240 may provide a near-infrared reflection function of the solar light reflection layer 241 in the selective emission layer.

However, when the sunlight reflective layer 241 is present, the reflectance for near-infrared rays may be increased.

The selective emission layer according to an embodiment of the present invention has a first refractive index with respect to near-infrared rays, a binder material 242 that absorbs and emits long-wavelength infrared rays, has a second refractive index with respect to near-infrared rays, and absorbs and emits long-wavelength infrared rays. It may be formed of at least one layer that reflects near-infrared rays based on a refractive index difference between the inorganic nano- or micro-particles 243 and the pores 244 having a third refractive index for near-infrared rays.

According to an embodiment of the present invention, the radiation cooling layer 230 and the radiation cooling layer 240 can be viewed as a structure that increases the reflection of sunlight through efficient diffuse reflection due to a difference in refractive index.

3 is a view for explaining optical characteristics related to a ratio obtained by dividing an extinction coefficient for each wavelength by a refractive index in relation to a radiation cooling layer of a color radiation cooling device according to an embodiment of the present invention.

₃ illustrates a ratio obtained by dividing the extinction coefficient in each wavelength band of the radiation cooling layer by the refractive index when the nano or micro particles forming the radiation cooling layer according to an embodiment of the present invention are formed of Al ₂ O 3 and SiO ₂ do.

Referring to the graph 300 of FIG. 3 , the graph 300 represents a ratio (k/n) for each wavelength, a first leader line 301 represents Al ₂ O ₃ , and a second leader line 302 . may represent _{SiO 2 .}

A point 303 on the first leader line 301 and the second leader line 302 of the graph 300 may indicate complementary emission properties.

Since the first leader line 301 is high after 12 μm and the second leader line 302 is high at 8 μm to 10 μm, the first leader line 301 radiates after 12 μm, and the second leader line 302 radiates from 8 μm to 10 μm. It can exhibit radiation characteristics at 10 μm.

Therefore, when Al ₂ O ₃ and SiO ₂ are mixed, these radiation characteristics are overlapped, and thus a high emissivity can be obtained in the window region of the atmosphere.

The above-described radiation characteristics may be derived based on the following [Equation 1].

[Equation 1]

In [Equation 1], R may represent reflectance, n ₀ may represent the refractive index of air, n ₁ may represent the refractive index of the medium, and k may represent the extinction coefficient of the material.

Nano or micro particles also have similar trends in the refractive index and extinction coefficient for each wavelength of the thin film, so a mixture of these materials with optimized composition and particle size can result in high emissivity in the entire window of the atmosphere.

Accordingly, the radiation cooling device according to an embodiment of the present invention may have a high emissivity in the entire window of the atmosphere.

For example, the emissivity in the overall atmospheric transparency window can also be economical in manufacturing and material costs due to the abundance of materials and simple coating processes such as blade coating and drop casting.

4A to 4C are views for explaining various images related to the radiation cooling layer of the color-type radiation cooling device according to an embodiment of the present invention.

4A illustrates a scanning microscope image of a plane of a radiation cooling layer according to an embodiment of the present invention, and FIG. 4B illustrates a scanning microscope image of a tomographic plane of a radiation cooling layer according to an embodiment of the present invention.

4C illustrates an image of a radiative cooling layer formed with a matte white appearance with high diffuse reflectivity.

Referring to image 400 of FIG. 4A and image 410 of FIG. 4B , Al ₂ O ₃ particles and SiO ₂ particles are well bonded together with a support of UV curing DPHA binder used as a binder material between the particles. can confirm.

Referring to the image 420 of FIG. 4C , it can be confirmed that the matte white color is important for reducing eye fatigue compared to the case of the PDRC (passive daytime radiative cooling) structure including the efficient reflection of the solar light flux and the metal mirror layer. have.

It can be seen that the image 420 has a matte white color rather than a silver surface such as a mirror.

The image 420 may represent an image in which a paint material used for the radiation cooling layer according to an embodiment of the present invention is formed.

In the image 400 of FIG. 4A and the image 410 of FIG. 4B , the radiation cooling layer has _{a mixture of Al 2} O ₃ and SiO ₂ and a binder when the ratio _{of Al 2} O ₃ and SiO ₂ is 1:1. It may be a paint coating layer formed using a 2:1 paint.

That is, in the color radiation cooling device according to an embodiment of the present invention, the radiation cooling layer constituting the lower layer may be formed of a paint film layer formed by applying the radiation cooling paint.

5A and 5B are diagrams for explaining optical characteristics and average emissivity for each angle within a window of the atmosphere in relation to a radiation cooling layer of a color-type radiation cooling device according to an embodiment of the present invention.

5A compares optical properties related to radiative cooling performance of a white paint according to the prior art and a paint according to an embodiment of the present invention.

Referring to the graph 500 of FIG. 5A , the white paint according to the prior art corresponds to the first leader line 501 , and the radiation cooling layer using the paint according to the embodiment of the present invention corresponds to the second leader line 502 . do.

5B compares the average emissivity of the white paint according to the prior art and the paint according to an embodiment of the present invention for each angle in the window of the atmosphere.

Referring to the graph 510 of FIG. 5B , the white paint according to the prior art corresponds to the indicator point 511 , and the paint forming the radiation cooling layer according to the embodiment of the present invention corresponds to the indicator point 512 . do.

When comparing the optical properties of the paint according to the embodiment of the present invention and the white paint, the paint according to the embodiment of the present invention exhibited high bandgap energy and light scattering in the UV-near visible light region and the NIR region due to high bandgap energy and light scattering. It absorbs less sunlight than paint.

In addition, the average atmospheric window emissivity of the paint according to an embodiment of the present invention is 93.5%, which is higher than that of the conventional white paint of 92.6%. It can be seen that it appears to be excellent.

More specifically, _{a conventional white paint composed of TiO 2} particles and an acrylic binder exhibiting NIR band absorption exhibited a solar weight absorption of 0.112 and an average emissivity of 0.924 in the atmospheric transparency window.

On the other hand, it can be seen that the paint according to an embodiment of the present invention exhibits an extremely low solar weight absorption of 0.041 and a high average emissivity of 0.935 due to the balanced composition and thickness _{of Al 2} O ₃ and SiO _{2 particles and DPHA.}

In addition, the paint according to an embodiment of the present invention _{shows strong radiation characteristics at angles generated due to harmonics of Al 2} O ₃ and SiO ₂ particles compared to conventional white paint, resulting in a high result of 0.8 at an incident angle of 60 degrees. can be checked

6A and 6B are views for explaining optical characteristics of a material forming a wavelength conversion absorption light emitting layer of a color radiation cooling device according to an embodiment of the present invention.

6A illustrates an emission spectrum with respect to a luminous body of a wavelength conversion absorption light emitting layer of a color-type radiation cooling device according to an embodiment of the present invention.

Referring to the graph 600 of FIG. 6A , emission when silica is coated on a shell of perovskite materials used as a material for forming a wavelength conversion absorption light emitting layer of a color radiation cooling device according to an embodiment of the present invention represents the spectrum.

The first leader line 601 of the graph 600 may correspond to the emission spectrum of green-colored particles coated with SiO _{2 on CPB 3 that may exhibit a green color among perovskite materials.}

The second leader line 602 of the graph 600 may correspond to an emission spectrum of particles of a red color in which SiO _{2 is coated on CPB x} I _{3-x capable of exhibiting a red color among perovskite materials.}

The first leader line 601 indicates that green-colored particles have a characteristic of emitting light at 470 nm to 550 nm.

The second leader line 602 indicates that the red particle has a characteristic of emitting light at 600 nm to 700 nm.

6B illustrates an absorption spectrum in relation to a light emitting body of a wavelength conversion absorption light emitting layer of a color radiation cooling device according to an embodiment of the present invention.

Referring to the graph 610 of FIG. 6B , absorption when silica is coated on a shell of perovskite materials used as a material for forming a wavelength conversion absorption emission layer of a color radiation cooling device according to an embodiment of the present invention represents the spectrum.

The first leader line 611 of the graph 610 may correspond to the emission spectrum of green-colored particles in which SiO _{2 is coated on CPB 3 that may exhibit a green color among perovskite materials.}

The second leader line 612 of the graph 610 may correspond to the emission spectrum of particles of red color in which SiO _{2 is coated on CPB x} I _{3-x capable of exhibiting a red color among perovskite materials.}

The first leader line 611 indicates that green-colored particles have a characteristic of absorbing light at 470 nm to 550 nm.

The second leader line 612 indicates that the red particle has a characteristic of absorbing light at 600 nm to 700 nm.

6C is a view for explaining the color realization characteristics of the material forming the wavelength conversion absorption light emitting layer of the color-type radiation cooling device according to an embodiment of the present invention.

Specifically, FIG. 6c shows green colored particles and peroves coated with SiO _{2 on CPB 3} capable of exhibiting a green color among perovskite materials that are materials for forming a wavelength conversion absorption light emitting layer according to an embodiment of the present invention. _{CPB x} I _3-x capable of exhibiting a red color among skyite materials and SiO ₂ exemplifies the luminescent properties of red particles coated with SiO 2 .

Referring to FIG. 6C , the container 620, the container 621, the container 622 and the container 623 are illustrated, and the container 620 and the container 622 contain green colored particles, and the container ( Red color particles are included in 621 and the container 623 .

The container 620 and the container 621 correspond to images photographed using a general camera, and the container 622 and the container 623 are images photographed using an ultraviolet camera.

Vessel 622 and vessel 623 confirm the luminescent properties of the perovskite material.

Therefore, the present invention can provide a color-type radiation cooling device capable of realizing a vivid color in consideration of the user's aesthetic point of view.

7A to 7C are views for explaining an implementation image of a color-type radiation cooling device and optical characteristics of a color-type radiation cooling device according to an embodiment of the present invention.

7A is implemented with various structures of the color-type radiation cooling element according to an embodiment of the present invention, and illustrates an image obtained by photographing the implemented color-type radiation cooling element.

Referring to FIG. 7A , an image 700 exemplifies a case in which a coating film of 319 μm is formed by spray-coating a commercial red paint spray on a glass substrate.

That is, the image 700 may exemplify a color-type radiation cooling device including only a color realization layer.

Image 701 shows a case of forming a layer of about 28 μm by spray coating a commercial red paint spray on a glass substrate to form a 242 μm coating, and then spin coating a solution in which silica-coated red particles are dispersed. to exemplify

That is, the image 701 illustrates a color-type radiation cooling device in which a wavelength conversion absorption light emitting layer is formed on the color realization layer.

Image 702 illustrates a chromatic radiant cooling element forming a color realizing layer on the radiative cooling layer.

Specifically, the image 702 _{is a mixture of Al 2} O ₃ and SiO ₂ microparticle powder (particle size of 0.8 μm to 1.2 μm) in a volume ratio of 1:1, and then the binder material DPHA is mixed with a particle ratio: binder ratio = 2:1. Mix, add a small amount of UV initiator (Irgacure 184), put it in an ethanol solvent, disperse it to prepare a solution, apply it on a glass substrate, and after the solvent is dry, irradiate with UV for 10 minutes to form a coating film of about 253㎛ , a case in which a 25㎛ coating film is formed by spray-coating a commercial red paint spray is exemplified.

Image 703 illustrates a color-type radiation cooling device in which a color realization layer is formed on a radiation cooling layer, and a wavelength conversion absorption emitting layer is formed on the color realization layer.

Specifically, the image 703 _{is a mixture of Al 2} O ₃ and SiO ₂ microparticle powder (particle size of 0.8 μm to 1.2 μm) in a volume ratio of 1:1, and then the binder material DPHA is mixed with a particle ratio: binder ratio = 2:1. After mixing, add a small amount of UV initiator (Irgacure 184), put it in an ethanol solvent and disperse it to prepare a solution. , a case of forming a 23 μm coating film by spray coating a commercially available red paint spray, and spin coating a solution in which silica-coated red particles are dispersed to form a layer of about 20 μm is exemplified.

The results of measuring optical properties of the color radiation cooling elements of the images 700 to 703 through experimental equipment will be described with reference to FIGS. 7B and 7C .

7B is a view for explaining the reflectance of the color-type radiation cooling device according to an embodiment of the present invention.

Referring to the graph 710 of FIG. 7B , the first leader line 711 corresponds to the image 700 of FIG. 7A , the second leader line 712 corresponds to the image 701 of FIG. 7A , and the third leader line 713 may correspond to the image 702 of FIG. 7A , and the fourth leader line 714 may correspond to the image 703 of FIG. 7A .

The chromatic radiation cooling elements of images 700 and 702 do not include a wavelength converting absorption emitting layer, and the chromatic radiation cooling elements of images 701 and 703 include a wavelength converting absorption emitting layer, and have.

It can be seen that the reflectances of the first and third leaders 711 and 713 and the second and fourth leaders 712 and 714 are compared.

The chromatic radiative cooling elements of images 700 and 701 do not include a radiative cooling layer, and the chromatic radiative cooling elements of images 702 and 703 contain a radiative cooling layer.

Comparing the reflectance of the first and second leaders 711 and 712, and the third and fourth leaders 713 and 714, it can be seen that the reflectance of near-infrared rays increases when the radiation cooling layer is included. .

The measurement results of the graph 710 can be summarized as shown in Table 1 below, on the other hand, the image 700 is the first sample, the image 701 is the second sample, the image 702 is the third sample, and the image 703 may be referred to as a fourth sample.

[Table 1]

In Table 1, it can be seen that the solar reflectance corresponding to the near-infrared reflectance of the third sample and the fourth sample increases.

On the other hand, in the third sample and the fourth sample, as the wavelength conversion absorption layer absorbs and emits ultraviolet rays, the solar absorption rate also increases, but the absorbed sunlight is emitted again, so that heat inflow can be minimized.

7c is a view for explaining the emissivity of the color-type radiation cooling device according to an embodiment of the present invention.

Referring to the graph 720 of FIG. 7C , the first leader line 721 corresponds to the image 700 of FIG. 7A , the second leader line 722 corresponds to the image 701 of FIG. 7A , and the third leader line 723 may correspond to the image 702 of FIG. 7A , and the fourth leader line 724 may correspond to the image 703 of FIG. 7A .

The chromatic radiation cooling elements of images 700 and 702 do not include a wavelength converting absorption emitting layer, and the chromatic radiation cooling elements of images 701 and 703 include a wavelength converting absorption emitting layer, and have.

The chromatic radiative cooling elements of images 700 and 701 do not include a radiative cooling layer, and the chromatic radiative cooling elements of images 702 and 703 contain a radiative cooling layer.

Comparing the emissivity of the first leader line 721 to the fourth leader line 724, it can be seen that the emissivity of the long-wavelength infrared rays is similar in the window section of the atmosphere.

The optical characteristics of the color-type radiation cooling device of the images 700 to 703 based on the graph 720 can be summarized as shown in Table 2 below.

Meanwhile, the image 700 may be referred to as a first sample, the image 701 may be referred to as a second sample, the image 702 may be referred to as a third sample, and the image 703 may be referred to as a fourth sample.

[Table 2]

In Table 2, the solar absorptivity may be related to the reflectance of near-infrared rays, the solar absorptance and the reflectance for near-infrared rays may represent an inversely proportional relationship, and the window emissivity of the atmosphere may indicate the emissivity of long-wavelength infrared rays.

Table 2 shows that the solar reflectance is increased in the third and fourth samples to which the radiative cooling layer is added, and it is confirmed that the wavelength-converted absorption emitting layer does not decrease the solar reflectance associated with radiative cooling and the window emissivity of the atmosphere. makes it

On the other hand, the wavelength conversion absorption-emitting layer absorbs and emits the remaining visible light other than the visible light for color realization with respect to the visible light region absorbed by the color realization layer, thereby minimizing heat inflow into the color-type radiation cooling device.

Therefore, the present invention cools the ambient temperature of the radiation cooling element without energy consumption even during day time when sunlight is shining or night time when sunlight is not shining, so that materials requiring cooling of buildings, automobiles, etc. It is possible to provide a color-type radiant cooling element that can be applied to an external surface to perform a cooling function without energy consumption.

The present invention can improve the energy efficiency of a cooling system by applying a color radiant cooling element to the cooling system.

8A and 8B are diagrams illustrating an experimental environment using a color-type radiation cooling device according to an embodiment of the present invention and radiative cooling performance measured in the experimental environment.

8A illustrates an experimental environment using various color-type radiation cooling devices according to an embodiment of the present invention. Here, the various color-type radiation cooling elements may correspond to the color-type radiation cooling elements of images 700 to 703 of FIG. 7A .

For example, the image 700 may be referred to as a first sample, the image 701 may be referred to as a second sample, the image 702 may be referred to as a third sample, and the image 703 may be referred to as a fourth sample.

Referring to FIG. 8A , a first sample 801 , a second sample 802 , a third sample 803 and a 4 The samples 804 are arranged and placed in the same environment.

FIG. 8B illustrates optical properties related to radiative cooling performance measured in an experimental environment using the various color-type radiative cooling elements of FIG. 8A.

Referring to FIG. 8B , a graph 810 is a first graph using a first leader line 811 , a second leader line 812 , a third leader line 813 , a fourth leader line 814 , and a fifth leader line 815 . The change in temperature related to the radiative cooling performance based on the samples 801 to the fourth sample 804 is illustrated.

The first leader line 811 indicates the measurement result of the first sample 801 , the second leader line 812 indicates the measurement result of the second sample 802 , and the third leader line 813 indicates the third sample 803 . ), a fourth leader line 814 may indicate a measurement result of the fourth sample 804 , and a fifth leader line 815 may indicate a measurement result of ambient air.

The measurement results of the graph 810 may be summarized in Table 3 below.

[Table 3]

Referring to Table 3, it can be confirmed that the first sample, the second sample, and the third sample and the fourth sample provide the effect of minimizing heat inflow based on the wavelength conversion absorption and emission layer.

Specifically, the second sample was cooled by about 1.6°C more and the fourth sample was cooled by about 5.1°C more than the first sample.

In the case of the first sample, the color conversion layer absorbs both visible light and ultraviolet light, but in the case of the second sample and the fourth sample, the wavelength conversion absorption and emission layer absorbs the ultraviolet light and visible light to be absorbed by the color conversion layer to form a color type. It can be seen that the heat input in the radiative cooling element is reduced.

In other words, the second sample can further cool the ambient temperature by about 1.6° C. due to the effect of minimizing heat inflow without changing the color implemented by the color realization layer due to the effect of the wavelength conversion absorption and emission layer.

On the other hand, in the fourth sample, the effect of the near-infrared reflection and long-wavelength infrared absorption and emission of the radiation cooling layer and the effect of the wavelength conversion absorption and emission layer to minimize heat inflow without changing the color realized by the wavelength conversion absorption and emission layer, the ambient temperature was reduced to about 5.1 ° C. can be further cooled.

Therefore, the present invention can provide a color-type radiation cooling device that has high reflectivity in the near-infrared region with respect to incident sunlight, provides a vivid color, and minimizes heat inflow through wavelength conversion absorption and emission using phosphor particles. .

In the above-described specific embodiments, elements included in the invention are expressed in the singular or plural according to the specific embodiments presented.

However, the singular or plural expression is appropriately selected for the situation presented for convenience of description, and the above-described embodiments are not limited to the singular or plural component, and even if the component is expressed in plural, it is composed of a singular or , even a component expressed in the singular may be composed of a plural.

On the other hand, although specific embodiments have been described in the description of the invention, various modifications are possible without departing from the scope of the technical idea contained in the various embodiments.

Therefore, the scope of the present invention should not be limited to the described embodiments, but should be defined by the claims described below as well as the claims and equivalents.

100: colorful radiative cooling element 110: radiant cooling layer
120: color realization layer 130: wavelength conversion absorption light emitting layer

Claims (15)

a color realization layer that reflects near-infrared rays of incident sunlight and absorbs specific visible rays of the incident sunlight to implement at least one color;
A wavelength conversion absorption light emitting layer that is located on the color realization layer and is formed of a light emitting body that absorbs and emits the remaining visible rays other than the ultraviolet rays of the incident sunlight and the absorbed specific visible rays to reduce the heat inflow according to the absorption of the incident sunlight ; and
A radiation cooling layer that is located under the color realization layer, absorbs and emits long-wavelength infrared rays in a wavelength range corresponding to a sky window, and increases the reflectivity of the near-infrared rays by reflecting the near-infrared rays;
The wavelength conversion absorption light emitting layer emits a color similar to the at least one color implemented based on the light emitting body, so that the color realization layer and the absorption section in the solar spectrum overlap
Colorful radiant cooling element. According to claim 1,
The radiation cooling layer is characterized in that it is formed in any one of a single metal thin film structure, a multilayer thin film structure, a particle dispersion structure in a polymer matrix, a polymer pore structure, and a binder polymer structure.
Colorful radiant cooling element. 3. The method of claim 2,
The single metal thin film structure includes a metal solar reflective layer that reflects the near-infrared light based on a metal material,
The multilayer thin film structure is formed of at least one layer of any one of a polymer material and an inorganic material that absorbs and emits the long-wavelength infrared light on the metal solar reflective layer, or a mixed material in which at least one material is mixed,
The particle dispersion structure in the polymer matrix is characterized in that the inorganic nano or micro particles are dispersed in the polymer matrix based on the polymer material on the metal solar reflective layer to form at least one layer.
Colorful radiant cooling element. 4. The method of claim 3,
The polymer pore structure is formed to include a polymer material that absorbs and emits the long-wavelength infrared light and an air gap, and scatters and scatters the incident sunlight based on a refractive index difference between the polymer material and the air gap It is formed of at least one layer that reflects and reflects the near-infrared rays,
The binder polymer structure has a first refractive index with respect to the near-infrared rays, a binder material absorbing and emitting the long-wavelength infrared rays, a second refractive index with respect to the near-infrared rays, and inorganic nanoparticles or micro particles that absorb and emit the long-wavelength infrared rays and at least one layer that reflects the near-infrared rays based on a difference in refractive index between an air gap having a third refractive index with respect to the near-infrared rays.
Colorful radiant cooling element. 5. The method of claim 4,
The polymer material is DPHA (DiPentaerythritol HexaAcrylate), PDMS (polydimethylsiloane), ETFE (Ethylene Tetra fluoro Ethylene), PUA (poly urethane acrylate), PS (polystyrene), PET (polyethylene terephthalate), PE (polyethylene), PC (polycarbonate) , PVDF (Polyvinylidene fluoride), PCTFE (Polychlorotrifluoroethylene) and polyethylene oxide (Polyethylene oxide) characterized in that it comprises at least one polymer material
Colorful radiant cooling element. 5. The method of claim 4,
The inorganic material is SiO ₂ , Si ₃ N ₄ , Al ₂ O ₃ , Ta ₂ O ₅ , c-BN, CaSO ₄ , MgHPO ₄ , ZrO ₂ , _{BaSO 4} , CaCO ₃ , AlN, AlPO ₄ , Y ₂ O ₃ of characterized in that it contains at least one mineral
Colorful radiant cooling element. 5. The method of claim 4,
The binder material is DPHA (DiPentaerythritol HexaAcrylate), PDMS (polydimethylsiloane), ETFE (Ethylene Tetra fluoro Ethylene), PUA (poly urethane acrylate), PS (polystyrene), PET (polyethylene terephthalate), PE (polyethylene), PC (polycarbonate) , PVDF (Polyvinylidene fluoride), PCTFE (Polychlorotrifluoroethylene), polyethylene oxide (Polyethylene oxide), acrylic (Acrylic)-based polymer, polyester (Polyester)-based polymer and urethane (ethance) containing at least one binder material of the polymer characterized
Colorful radiant cooling element. 4. The method of claim 3,
The metal material is silver (Ag), aluminum (Al), gold (Au), copper (cu), titanium (Ti), chromium (Cr), manganese (Mn), iron (Fe), platinum (Pt), lithium At least one metal material selected from (Li) and sodium (Na), or at least two alloy materials combined with any one material
Colorful radiant cooling element. According to claim 1,
The light-emitting body is characterized in that it is formed of any one of a perovskite material and a chalcogenide-based material.
Colorful radiant cooling element. 10. The method of claim 9,
The light-emitting body is characterized in that any one of inorganic materials and polymer materials is coated on a shell of particles based on any one of the perovskite material and the chalcogenide-based material. doing
Colorful radiant cooling element. 11. The method of claim 10,
The polymer material is DPHA (DiPentaerythritol HexaAcrylate), PDMS (polydimethylsiloane), ETFE (Ethylene Tetra fluoro Ethylene), PUA (poly urethane acrylate), PS (polystyrene), PET (polyethylene terephthalate), PE (polyethylene), PC (polycarbonate) , PVDF (Polyvinylidene fluoride), PCTFE (Polychlorotrifluoroethylene), and containing at least one polymer material of polyethylene oxide (Polyethylene oxide),
The inorganic material is SiO ₂ , Si ₃ N ₄ , Al ₂ O ₃ , Ta ₂ O ₅ , c-BN, CaSO ₄ , MgHPO ₄ , ZrO ₂ , _{BaSO 4} , CaCO ₃ , AlN, AlPO ₄ , Y ₂ O ₃ of characterized in that it contains at least one mineral
Colorful radiant cooling element. delete According to claim 1,
The radiation cooling layer is formed using at least one of a polymer material, a binder material, a metal material, an inorganic material, and nano or micro particles of an inorganic material, and the wavelength corresponding to the sky window of the at least one material characterized in that the emissivity for the long-wavelength infrared is increased as the at least one material is combined so that the emissivity for the long-wavelength infrared in the range is mutually complementary
Colorful radiant cooling element. According to claim 1,
The color realization layer, the wavelength conversion absorption light emitting layer, and the radiation cooling layer may be formed by drop casting, spin coating, bar coating, spray coating, or blade coating. , characterized in that the coating is formed on various surfaces through at least one solution process of dying (dyeing) and brushing (brushing)
Colorful radiant cooling element. 15. The method of claim 14,
wherein the various surfaces include at least one of a wood surface, a glass surface, a metal substrate surface, a plastic surface, and a cloth surface.
Colorful radiant cooling element.

Images