Radiation cooling element with multi-layer structure

Abstract

The present invention relates to a technical purpose that minimizes the absorption of light in the solar spectrum, while absorbing and radiating long wavelength infrared rays corresponding to the wavelength range of the atmospheric window, and radiating the heat below the element to the outside, thereby cooling the temperature of the material surface or below the material, thereby reducing the temperature of the material surface or below the material. The present invention is a technique for providing a radiation cooling element of a multilayer structure, which performs selective radiation in a wavelength range of an atmospheric window using a radiation cooling element of a multilayer structure having a polymer and an inorganic substance, and at the same time, can increase reflection of sunlight by means of a difference in refractive index of a molding material.

Description

[0001] This application is a divisional application of the Chinese patent application with application number 202011403350.4 and invention name “Radiative Cooling Element with Multi-layer Structure”. The filing date of the original application is December 4, 2020. Technical Field

[0002] The present invention relates to a technical purpose, which is characterized in that the absorption of light in the solar spectrum is minimized, and at the same time, long-wavelength infrared rays equivalent to the wavelength range of the atmospheric window are absorbed and radiated, and the heat under the element is radiated to the outside, thereby cooling the temperature of the material surface or under the material. The present invention is a technology for providing a radiation cooling element with a multilayer structure, and the radiation cooling element is characterized in that selective radiation is performed within the wavelength range of the atmospheric window by utilizing a radiation cooling element with a multilayer structure of polymers and inorganic substances, and at the same time, the reflection of sunlight can be increased by the refractive index difference of the molding material. Background Art

[0003] Passive radiative cooling (Radiative Cooling) elements reflect wavelengths equivalent to daytime sunlight (0.3-2.5 μm) and passively cool by emitting radiant heat (8-13 μm) energy that can escape the universe.

[0004] On the other hand, passive radiative heating elements absorb wavelengths equivalent to daytime sunlight (0.3-2.5μm), and are poor at absorbing radiant heat (8-13μm) that can escape from the universe, so they cool passively.

[0005] The efficiency of passive cooling elements can be checked by measuring the optical properties of the element itself.

[0006] In order to dissipate heat, it is necessary to have a high absorptivity or a high emissivity in the long-wavelength infrared region, thereby being able to sufficiently dissipate heat into the universe.

[0007] According to the Planck distribution, when the temperature is 300K, there is a condition that can maximize heat dissipation in the wavelength region of 6-20μm. On Earth, the wavelength range equivalent to the sky window is about 8-13μm, so in order to maximize the heat dissipation capacity of the passive cooling element, the absorptivity or emissivity in the 8-13μm region should be maximized.

[0008] Infrared radiation in the atmospheric window wavelength range plays a key role in achieving radiative cooling by actually dissipating the heat.

[0009] If the wavelength range can reflect 100% of the incident sunlight (radiation from the sun) of ultraviolet-visible light-near infrared rays, and the long-wavelength infrared rays of 8-13μm equivalent to the atmospheric window can be 100% emitted to the outside, then 158W / m can be achieved without consuming energy at an ambient temperature of 300K. 2 cooling performance.

[0010] If 95% of sunlight is reflected and more than 90% of mid-infrared in the 8-13μm region is radiated to the outside, when the ambient temperature is 300K, the daytime cooling performance is 100W / m 2 (i.e., there is solar light absorption), and the nighttime cooling performance without solar light absorption is 120 W / m 2 .

[0011] In order to be used as a passive radiation cooling material, it should not absorb incident sunlight due to high transmittance or high reflectivity for light in the ultraviolet and near-infrared (UV-vis-NIR) wavelength range of the incident sunlight, and should have a high absorption (radiation) rate for long-wave infrared light in the 8-13μm region band, which is a wavelength range interval equivalent to the atmospheric window. In addition, it must have high durability (stability, corrosion resistance) even under outdoor conditions. The materials used must be cheap and available in large quantities, and must be capable of large-area molding by a cheap and easy method.

[0012] Polymer materials generally have a high absorptivity (emissivity) to long-wavelength infrared rays, but due to the nature of the material, they are easily degraded by ultraviolet rays or moisture when placed outdoors, resulting in a short service life.

[0013] In addition, since the thick polymer material is a broadband emitter with high emissivity at all infrared wavelengths, the radiative cooling performance is not as good as a selective emitter with high emissivity in the atmospheric window.

[0014] In the sky windows zone, for high radiation, materials with high extinction coefficient values ​​can be used in the 8-13 μm region. However, since the wavelength range of the 8-133 μm region is wide, it is difficult to find materials with high extinction coefficient values ​​in all fields.

[0015] Most substances have their absorption values ​​changed due to the bonding of their constituent molecules, and sometimes their absorption wavelength range is changed due to the bonding and resonance of their constituent molecules.

[0016] For example, in the case of Al2O3, it starts to increase from about 10μm, SiO2 is difficult to be satisfied in all wavelength ranges such as 8-10μm, and in the case of inorganic substances in the form of thin films, even if the thickness becomes thicker, it is difficult to exceed the limit of the material and increase the absorption.

[0017] The absorption wavelength of organic matter also changes depending on the bonding method used. However, if the thickness of the organic matter is 50 μm or more, it has high absorption power not only in 8-13 μm, but also in the entire wavelength. Since absorption of wavelengths other than 8-13 μm theoretically reduces the radiation cooling performance (under low ambient temperature conditions), it is necessary to use an emitter in the 8-13 μm region to solve this problem.

[0018] Prior art literature

[0019] Patent Literature

[0020] (Patent Document 1) Korean Patent Publication No. 10-2019-0130985, "Passive Radiative Cooling Structure"

[0021] (Patent Document 2) Korean Patent Registration No. 10-2036071, "Multi-layer Radiative Cooling Structure"

[0022] (Patent Document 3) U.S. Patent Publication No. 2018 / 0354848, “Passive Radiative Cooling of Atmospheric Window Structures”

[0023] (Patent Document 4) U.S. Patent Publication No. 2020 / 0095429, "Cooling a surface coating by passive radiative cooling" Summary of the invention

[0024] Technical issues

[0025] The present invention aims to improve the radiation cooling performance of a radiation cooling element by providing a radiation cooling layer having a multilayer structure based on a polymer and an inorganic substance with a maximum emissivity in a wavelength range corresponding to an atmospheric window.

[0026] The present invention aims to improve the radiation cooling performance of a radiation cooling element by increasing the reflectivity by using a metal or alloy material having high reflectivity to sunlight and constructing a sunlight reflecting layer having excellent chemical stability.

[0027] The purpose of the present invention is to have the maximum emissivity within the wavelength range of various multilayer structures including inorganic layers, polymer layers, composite inorganic layers and inorganic and polymer composite layers and equivalent to the atmospheric window, thereby improving the radiation cooling performance of the radiation cooling element.

[0028] The object of the present invention is to provide a radiation cooling element which can achieve high reflectivity only by a multilayer structure without a sunlight reflecting layer, so that the multilayer structure replaces the function of the sunlight reflecting layer.

[0029] An object of the present invention is to provide a radiation cooling element that cools to below ambient temperature without consuming energy even during the daytime when sunlight is incident or at nighttime when sunlight is not incident, and that performs a cooling function without consuming energy by being applied to an external surface of a material to be cooled, such as a building or a car.

[0030] Technical Solution

[0031] According to an embodiment of the present invention, a radiation cooling element of a multi-layer structure may include at least one layer of an inorganic layer, a polymer layer, a composite inorganic layer and a composite polymer layer in at least one pair to form a multi-layer structure, and may include a radiation cooling layer that absorbs and radiates infrared rays within a wavelength range equivalent to a sky window while reflecting sunlight based on the multi-layer structure.

[0032] The multilayer structure may include at least one of the four structures described below: a first structure in which the inorganic layer is laminated on the polymer layer; a second structure in which the polymer layer is laminated again after the inorganic layer is laminated on the polymer layer; a third structure in which the polymer layer is laminated on the inorganic layer; and a fourth structure in which the inorganic layer is laminated again after the polymer layer is laminated on the inorganic layer.

[0033] The multilayer structure may include at least one of the four repeating structures described below: a first repeating structure, wherein the first structure is repeatedly laminated at least once; a second repeating structure, wherein the second structure is repeatedly laminated at least once; a third repeating structure, wherein the third structure is repeatedly laminated at least once; and a fourth repeating structure, wherein the four structures are repeatedly laminated at least once.

[0034] The multilayer structure may include at least one of the two structures described below: a fifth structure, in which after the inorganic layer is laminated on the polymer layer, a polymer layer based on a polymer different from the molded polymer of the polymer layer is laminated; a sixth structure, in which after the polymer layer is laminated on the inorganic layer, a polymer layer based on a polymer different from the molded polymer of the polymer layer is laminated.

[0035] The multi-layer structure may include at least one of two repeating structures described below: a fifth repeating structure in which the fifth structure is repeatedly laminated at least once; and a sixth repeating structure in which the sixth structure is repeatedly laminated at least once.

[0036] The multilayer structure may include at least one of the five structures described below: a seventh structure, in which after the inorganic material is laminated on the inorganic and polymer composite layer, the inorganic and polymer composite layer is laminated again; an eighth structure, in which after the inorganic material is laminated on the inorganic and polymer composite layer, an inorganic and polymer composite layer including inorganic particles different from the inorganic particles contained in the inorganic and polymer composite layer is laminated; a ninth structure, in which after the polymer is laminated on the composite inorganic and polymer composite layer, an inorganic and polymer composite layer of a polymer different from a molded polymer based on the inorganic and polymer composite layer is laminated; a tenth structure, in which after the inorganic layer is laminated on the polymer layer, the polymer layer is laminated again; an eleventh structure, in which after the polymer is laminated on the inorganic layer, the inorganic layer is laminated again; and a twelfth structure, in which after the inorganic material is laminated on the polymer layer, the composite polymer layer is laminated again.

[0037] The multilayer structure may include at least one of the five repeating structures described below: a seventh repeating structure, wherein the seventh structure is repeatedly laminated at least once; an eighth repeating structure, wherein the eighth structure is repeatedly laminated at least once; a ninth repeating structure, wherein the ninth structure is repeatedly laminated at least once; and a tenth repeating structure, wherein the tenth structure is repeatedly laminated at least once; an eleventh repeating structure, wherein the eleventh structure is repeatedly laminated at least once; and a twelfth repeating structure, wherein the twelfth structure is repeatedly laminated at least once.

[0038] The inorganic layer can be formed of at least one inorganic substance selected from the group consisting of Al2O3, SiO2, BaSO4, LiF, CaSO4, ZnO, TiO2, ZrO2, CaF2, MgF2, HfO2, CaCO3, AlN, MgPHO4 and Si3N4.

[0039] The polymer layer can be made of PDMS (Polydimethyl siloxane), PUA (Poly urethaneacrylate), PVDF (Polyvinylidene fluoride), PET (polyethylene terephthalate), PVC (polyvinyl chloride), PVDF (Polyvinylidene fluoride), DPHA (Dipentaerythritol Hexaacrylate), PMMA (polymethyl methacrylate), PBMA (polymethyl methacrylate), PFPE (Perfluoropolyether), PC (Polycarbonate), PTFE (Polytetrafluoroethylene), Spectralon, ETFE (Ethylene Tetra fluoro Ethylene), and PE (polyethylene).

[0040] The inorganic and polymer composite layer can be formed by a mixture, which includes at least one inorganic substance selected from the group consisting of Al2O3, SiO2, BaSO4, LiF, CaSO4, ZnO, TiO2, ZrO2, CaF2, MgF2, HfO2, CaCO3, AlN, MgPHO4 and Si3N4 in at least one polymer selected from the group consisting of PDMS (Polydimethyl siloxane), PUA (Poly urethane acrylate), PVDF (Polyvinylidenefluoride), PET (polyethylene terephthalate), PVC (polyvinyl chloride), PVDF (Polyvinylidene fluoride), DPHA (Dipentaerythritol Hexaacrylate), PMMA (polymethyl methacrylate), PBMA (polymethyl methacrylate), PFPE (Perfluoropolyether), PC (Polycarbonate), PTFE (Polytetrafluoroethylene), Spectralon, ETFE (Ethylene Tetra fluoro Ethylene), and PE (polyethylene).

[0041] The composite inorganic layer is formed by mixing a first inorganic material selected from any one of Al2O3, SiO2, BaSO4, LiF, CaSO4, ZnO, TiO2, ZrO2, CaF2, MgF2, HfO2, CaCO3, AlN, MgPHO4 and Si3N4 and a second inorganic material different from the first inorganic material among Al2O3, SiO2, BaSO4, LiF, CaSO4, ZnO, TiO2, ZrO2, CaF2, MgF2, HfO2, CaCO3, AlN, MgPHO4 and Si3N4.

[0042] The composite polymer layer will be selected from PDMS (Polydimethyl siloxane), PUA (Poly urethaneacrylate), PVDF (Polyvinylidene fluoride), PET (polyethylene terephthalate), PVC (polyvinyl chloride), PVDF (Polyvinylidene fluoride), DPHA (Dipentaerythritol Hexaacrylate), PMMA (polymethyl methacrylate), PBMA (polymethyl methacrylate), PFPE (Perfluoropolyether), PC (Polycarbonate), PTFE (Polytetrafluoroethylene), Spectralon, ETFE (Ethylene Tetra fluoro Ethylene), and any first polymer of PE (polyethylene) and the PDMS (Polydimethyl siloxane), PUA (Poly urethane) acrylate), PVDF (Polyvinylidene fluoride), PET (polyethylene terephthalate), PVC (polyvinylchloride), PVDF (Polyvinylidene fluoride), DPHA (Dipentaerythritol The invention relates to a polymer that is different from the first polymer and is formed by mixing a second polymer selected from the group consisting of hexaacrylate, PMMA (polymethyl methacrylate), PBMA (polymethyl methacrylate), PFPE (Perfluoropolyether), PC (Polycarbonate), PTFE (Polytetrafluoroethylene), Spectralon, ETFE (Ethylene Tetra fluoro Ethylene), and PE (polyethylene).

[0043] The multi-layered radiation cooling element according to an embodiment of the present invention may further include: a sunlight reflecting layer formed of at least one of a metal material, at least one inorganic particle, and a polymer including the at least one inorganic particle, so as to reflect the sunlight.

[0044] The sunlight reflecting layer can be formed of at least one metal material selected from silver (Ag), aluminum (Al), gold (Au), copper (Cu), titanium (Ti), chromium (Cr), manganese (Mn), iron (Fe) and platinum (Pt), or any one of at least two combined alloy materials.

[0045] The sunlight reflecting layer includes at least one inorganic particle selected from the group consisting of MgF2, Al2O3, SiO2, MgO, ZnO, CaCO3, AlN, MgPHO4 and TiO2 or at least one polymer selected from the group consisting of PDMS (Polydimethyl siloxane), PUA (Poly urethane acrylate), PVDF (Polyvinylidene fluoride), PET (polyethylene terephthalate), PVC (polyvinyl chloride), PVDF (Polyvinylidene fluoride), DPHA (DipentaerythritolHexaacrylate), PMMA (polymethyl methacrylate), PBMA (polymethyl methacrylate), PFPE (Perfluoropolyether), PC (Polycarbonate), PTFE (Polytetrafluoroethylene), Spectralon, ETFE (Ethylene Tetra fluoro Ethylene), and PE (polyethylene), thereby reflecting sunlight based on the refractive index difference of the at least one inorganic particle.

[0046] Effects of the Invention

[0047] The present invention can improve the radiation cooling performance of the radiation cooling element by making the radiation cooling layer composed of a multilayer structure based on polymer and inorganic material have a maximum emissivity in a wavelength range equivalent to the atmospheric window.

[0048] The present invention improves the radiation cooling performance of the radiation cooling element by increasing the reflectivity by using a metal or alloy material having high reflectivity to sunlight and constructing a sunlight reflecting layer having excellent chemical stability.

[0049] The present invention has the maximum emissivity within the wavelength range equivalent to the atmospheric window including various multilayer structures such as inorganic layers, polymer layers, composite inorganic layers and inorganic and polymer composite layers, thereby improving the radiation cooling performance of the radiation cooling element.

[0050] The present invention provides a radiation cooling element which can achieve high reflectivity only through a multi-layer structure without a sunlight reflecting layer, so that the multi-layer structure replaces the function of the sunlight reflecting layer.

[0051] An object of the present invention is to provide a radiation cooling element that cools to below ambient temperature without consuming energy even during the daytime when sunlight is incident or at nighttime when sunlight is not incident, and that performs a cooling function without consuming energy by being applied to an external surface of a material to be cooled, such as a building or a car. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1A and Figure 1B is a diagram showing a radiation cooling element of a multi-layer structure according to an embodiment of the present invention;

[0053] FIG. 2A to FIG. 2D is a diagram showing a radiation cooling element having a multilayer structure based on a polymer layer and an inorganic layer according to an embodiment of the present invention;

[0054] Figure 3A and Figure 3B is a diagram showing a radiation cooling element having a multilayer structure based on at least one polymer layer and at least one inorganic layer according to an embodiment of the present invention;

[0055] FIG. 4A to FIG. 4C is a diagram showing a radiation cooling element having a multilayer structure based on a polymer layer, an inorganic layer, a composite polymer layer, a composite inorganic layer, and an inorganic and polymer composite layer according to an embodiment of the present invention;

[0056] FIG. 5A to FIG. 5F is a diagram showing an electron microscope image of a radiation cooling element of a multilayer structure according to an embodiment of the present invention;

[0057] FIG. 6A to FIG. 6C FIG. 5 is a graph showing the optical characteristics of a multi-layered radiation cooling element according to an embodiment of the present invention.

[0058] Explanation of symbols

[0059] 100: Radiative cooling element 101: Radiative cooling layer DETAILED DESCRIPTION

[0060] Hereinafter, various embodiments of the present document will be described with reference to the accompanying drawings.

[0061] The embodiments and the terms used therein are not intended to limit the technology described herein to specific embodiments, and should be understood to include various modifications, equivalents, and / or substitutes of the corresponding embodiments.

[0062] Hereinafter, in the description of various embodiments, if it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted.

[0063] In addition, the terms described later are defined in consideration of functions in various embodiments and may vary according to the intention or habits of a user or operator. Therefore, they should be defined based on the contents throughout the specification.

[0064] In conjunction with the description of the drawings, like reference numerals may be used for like constituent elements.

[0065] Unless the context clearly indicates otherwise, a singular expression may include a plural expression.

[0066] Herein, the expression "A or B" or "at least one of A and / or B" may include all possible combinations of the items listed together.

[0067] Expressions such as “first,” “second,” “first,” or “second” may describe corresponding constituent elements without considering the order or importance and are used to distinguish one constituent element from another constituent element but do not limit the corresponding constituent elements.

[0068] When a certain (for example, a first) component is described as being "connected" or "connected" (functionally or communicatively) to another (for example, a second) component, the one component may be directly connected to the other component or may be connected through another component (for example, a third component).

[0069] In this specification, “configured to” can be used interchangeably with “suitable for”, “possessing the ability to”, “changed to”, “made to”, “capable of doing”, and “designed to” in the form of hardware or software, depending on the situation.

[0070] In some cases, the expression "a device is configured to..." may mean that the device "can" be used with other devices or components.

[0071] For example, “a processor configured (or set) to perform A, B, and C” may refer to a dedicated processor (e.g., an embedded processor) for performing the corresponding operations, or a general-purpose processor (e.g., a CPU or an application processor) that can perform the corresponding operations by executing one or more software programs stored in a storage device.

[0072] In addition, the term "or" means an 'inclusive or' rather than an 'exclusive or'.

[0073] That is, unless otherwise stated or clear from the context, the expression 'x utilizes a or b' means any of the natural inclusive permutations.

[0074] Terms such as “unit” and “group” used below refer to a unit that performs at least one function or operation, which can be implemented by hardware or software or a combination of hardware and software.

[0075] Figure 1A and Figure 1B FIG. 1 is a diagram showing a radiation cooling device with a multi-layer structure according to an embodiment of the present invention.

[0076] Figure 1A A radiation cooling element 100 having a multi-layer structure without a sunlight reflecting layer according to an embodiment of the present invention is illustrated. In the following, for the convenience of description, the radiation cooling element 100 having a multi-layer structure is described as the radiation cooling element 100. Figure 1A , the radiation cooling element 100 includes a radiation cooling layer 101 .

[0077] According to an embodiment of the present invention, the radiation cooling layer 101 may include at least one layer of an inorganic layer, a polymer layer, a composite inorganic layer, and a composite polymer layer, which are included in at least one pair to form a multilayer structure, so that infrared rays within a wavelength range equivalent to the sky window can be absorbed and radiated based on the multilayer structure.

[0078] As an example, the radiation cooling layer 102 is composed of multiple layers of multiple materials, so that it reflects sunlight and can achieve high infrared radiation rate in the wavelength range corresponding to the atmospheric window.

[0079] The radiation cooling layer 102 according to an embodiment of the present invention reflects sunlight based on the difference in refractive index of materials forming the multilayer structure, thereby acting as a sunlight reflecting layer, and can absorb and radiate long-wavelength infrared rays within the wavelength range equivalent to the atmospheric window.

[0080] For example, refer to Figures 2A to 5F Supplementary explanation: the inorganic layer, polymer layer, composite inorganic layer, composite polymer layer, and composite inorganic and polymer layer of the radiation cooling layer 102 form at least one pair of multilayer structures.

[0081] According to one embodiment of the present invention, the multilayer structure of the radiation cooling layer 102 may include at least one of the four structures described below: a first structure in which an inorganic layer is laminated on the polymer layer; a second structure in which the polymer layer is laminated again after the inorganic layer is laminated on the polymer layer; a third structure in which the polymer layer is laminated on the inorganic layer; and a fourth structure in which the inorganic layer is laminated again after the polymer layer is laminated on the inorganic layer.

[0082] As an example, the multilayer structure of the radiation cooling layer 102 may include at least one of the four repeating structures described below: a first repeating structure, in which the first structure is repeatedly laminated at least once; a second repeating structure, in which the second structure is repeatedly laminated at least once; a third repeating structure, in which the third structure is repeatedly laminated at least once; and a fourth repeating structure, in which the four structures are repeatedly laminated at least once.

[0083] The multilayer structure of the radiation cooling layer 102 according to an embodiment of the present invention may include at least one of the two structures described below: a fifth structure, in which after the inorganic layer is laminated on the polymer layer, a polymer layer based on a polymer different from the molded polymer of the polymer layer is laminated; a sixth structure, in which after the inorganic layer is laminated on the polymer layer, a polymer layer based on a polymer different from the molded polymer of the polymer layer is laminated.

[0084] As an example, the multilayer structure of the radiation cooling element layer 102 may include at least one of the two repeating structures described below: a fifth repeating structure, the fifth structure of which is repeatedly laminated at least once; and a sixth repeating structure, the sixth structure of which is repeatedly laminated at least once.

[0085] According to one embodiment of the present invention, the multilayer structure of the radiation cooling layer 102 may include at least one of the five structures described below: According to one embodiment of the present invention, the multilayer structure of the radiation cooling layer 112 may include at least one of the five structures described below: a seventh structure in which, after the inorganic substance is laminated on the inorganic substance and polymer composite layer, the inorganic substance and polymer composite layer are laminated again; an eighth structure in which, after the inorganic substance is laminated on the inorganic substance and polymer composite layer, an inorganic substance and polymer composite layer including inorganic particles different from the inorganic particles contained in the inorganic substance and polymer composite layer is laminated; A ninth structure, in which after the inorganic layer is laminated on the inorganic and polymer composite layer, an inorganic and polymer composite layer based on a polymer different from the molding polymer of the inorganic and polymer composite layer is laminated; a tenth structure, in which after the composite inorganic layer is laminated on the polymer layer, the polymer layer is laminated again; an eleventh structure, in which after the polymer layer is laminated on the composite inorganic layer, the inorganic and polymer layers are laminated again; an eleventh structure, in which after the composite inorganic layer is laminated on the polymer layer, the polymer layer is laminated again; and a twelfth structure, in which after the inorganic layer is laminated on the composite polymer layer, the composite polymer layer is laminated again.

[0086] As an example, the multilayer structure of the radiation cooling layer 102 may include at least one of the five repeating structures described below: a seventh repeating structure, wherein the seventh structure is repeatedly laminated at least once; an eighth repeating structure, wherein the eighth structure is repeatedly laminated at least once; a ninth repeating structure, wherein the ninth structure is repeatedly laminated at least once; and a tenth repeating structure, wherein the tenth structure is repeatedly laminated at least once; an eleventh repeating structure, wherein the eleventh structure is repeatedly laminated at least once; and a twelfth repeating structure, wherein the twelfth structure is repeatedly laminated at least once.

[0087] In the above description, the multilayer structure of the radiation cooling layer 102 is exemplified as the first to twelfth structures, and although the first to twelfth structures exemplify the first to twelfth repeated structures laminated repeatedly, they are not limited to the corresponding structures and can be modified to more diverse structures.

[0088] As an example, the multilayer structure performs the functions of high solar reflection and selective radiation through the refractive index of the polymer or the refractive index of the inorganic substance constructed for higher solar reflection.

[0089] For example, a multilayer structure can be made to adjust the refractive index of each layer according to the material to be formed, thereby having a higher selective radiation function and realizing a radiation cooling element with low absorption and high reflection of sunlight.

[0090] For example, the selective radiation function may be a function of absorbing and radiating long-wavelength infrared rays in a wavelength range corresponding to an atmospheric window.

[0091] In addition, the multilayer structure can be modified to facilitate the reflection of sunlight and the radiation and absorption of infrared light in the wavelength range corresponding to the atmospheric window by the difference in the refractive index of the polymer or inorganic material of each layer.

[0092] According to one embodiment of the present invention, the inorganic layer constituting the radiation cooling layer 102 is formed by at least one inorganic substance selected from the group consisting of Al2O3, SiO2, BaSO4, LiF, CaSO4, ZnO, TiO2, ZrO2, CaF2, MgF2, HfO, CaCO3, AlN, MgPHO42 and Si3N4.

[0093] For example, the inorganic layer can be formed using various deposition methods such as spin coating, bar coating, dip-coating, and spray coating.

[0094] As an example, the polymer layer constituting the radiation cooling layer 102 can be formed of at least one polymer selected from the group consisting of PDMS (Polydimethylsiloxane), PUA (Poly urethane acrylate), PVDF (Polyvinylidene fluoride), PET (polyethylene terephthalate), PVC (polyvinyl chloride), PVDF (Polyvinylidenefluoride), DPHA (Dipentaerythritol Hexaacrylate), PMMA (polymethyl methacrylate), PBMA (polymethyl methacrylate), PFPE (Perfluoropolyether), PC (Polycarbonate), PTFE (Polytetrafluoroethylene), Spectralon, ETFE (Ethylene Tetra fluoro Ethylene), and PE (polyethylene).

[0095] For example, the polymer layer may be formed by mixing each polymer and a solvent together and using various deposition methods such as spin coating, bar coating, dip coating, and spray coating.

[0096] According to one embodiment of the present invention, the inorganic and polymer composite layers constituting the radiation cooling layer 102 may be formed into a mixture, and the mixture includes PDMS (Polydimethyl siloxane), PUA (Poly urethane acrylate), PVDF (Polyvinylidene fluoride), PET (polyethylene terephthalate), PVC (polyvinylchloride), PVDF (Polyvinylidene fluoride), DPHA (Dipentaerythritol Hexaacrylate), PMMA (polymethyl methacrylate), PBMA (polymethyl methacrylate), PFPE (Perfluoropolyether), PC (Polycarbonate), PTFE (Polytetrafluoroethylene), Spectralon, ETFE (Ethylene Tetra fluoro At least one of the polymers selected from the group consisting of polyethylene (ETHYLENE), polyethylene (ETHYLENE), and PE (polyethylene) contains at least one inorganic substance selected from the group consisting of Al2O3, SiO2, BaSO4, LiF, CaSO4, ZnO, TiO2, ZrO2, CaF2, MgF2, HfO2, CaCO3, AlN, MgPHO4 and Si3N4.

[0097] As an example, the composite inorganic layer of the radiation cooling layer 102 is formed by mixing a first inorganic substance selected from any one of Al2O3, SiO2, BaSO4, LiF, CaSO4, ZnO, TiO2, ZrO2, CaF2, MgF2, HfO2 and Si3N4 and a second inorganic substance different from the first inorganic substance selected from Al2O3, SiO2, BaSO4, LiF, CaSO4, ZnO, TiO2, ZrO2, CaF2, MgF2, HfO2, CaCO3, AlN, MgPHO4 and Si3N4.

[0098] According to an embodiment of the present invention, the composite polymer layer constituting the radiation cooling layer 102 is selected from PDMS (Polydimethyl siloxane), PUA (Poly urethane acrylate), PDMS (Polydimethylsiloxane), PUA (Poly urethane acrylate), PVDF (Polyvinylidene fluoride), PET (polyethylene terephthalate), PVC (polyvinyl chloride), PVDF (Polyvinylidenefluoride), DPHA (Dipentaerythritol Hexaacrylate), PMMA (polymethyl methacrylate), PBMA (polymethyl methacrylate), PFPE (Perfluoropolyether), PC (Polycarbonate), PTFE (Polytetrafluoroethylene), Spectralon, ETFE (Ethylene Tetra fluoro The invention relates to a method for preparing a nanostructured carbon nanotube film by mixing a first polymer selected from any one of Al2O3, SiO2, BaSO4, LiF, CaSO4, ZnO, TiO2, ZrO2, CaF2, MgF2, HfO2, CaCO3, AlN, MgPHO4 and Si3N4 and a second polymer selected from any one of the above-mentioned nanostructured carbon nanotube films.

[0099] The present invention provides a radiation cooling element, which has no sunlight reflecting layer and can achieve high reflectivity only through a multi-layer structure, so that the multi-layer structure replaces the function of the sunlight reflecting layer.

[0100] Figure 1B A radiation cooling element having a multi-layer structure including a sunlight reflecting layer according to an embodiment of the present invention is illustrated.

[0101] Reference Figure 1B The multi-layered radiation cooling element 110 according to an embodiment of the present invention includes a sunlight reflecting layer 111 and a radiation cooling layer 112. Hereinafter, for the convenience of description, the multi-layered radiation cooling element 110 is described as the radiation cooling element 110.

[0102] According to an embodiment of the present invention, the sunlight reflecting layer 111 is formed of at least one of a metal material, at least one inorganic particle, and a polymer including the at least one inorganic particle, so as to reflect the sunlight.

[0103] As an example, the sunlight reflecting layer can be formed of at least one metal material selected from silver (Ag), aluminum (Al), gold (Au), copper (Cu), titanium (Ti), chromium (Cr), manganese (Mn), iron (Fe) and platinum (Pt), or any one of at least two combined alloy materials.

[0104] In addition, the sunlight reflecting layer includes at least one inorganic particle in at least one inorganic particle selected from MgF2, Al2O3, SiO2, MgO, ZnO, CaCO3, AlN, MgPHO4 and TiO2 or at least one polymer selected from PDMS (Polydimethyl siloxane), PDMS (Polydimethylsiloxane), PUA (Poly urethane acrylate), PVDF (Polyvinylidene fluoride), PET (polyethylene terephthalate), PVC (polyvinyl chloride), PVDF (Polyvinylidenefluoride), DPHA (Dipentaerythritol Hexaacrylate), PMMA (polymethyl methacrylate), PBMA (polymethyl methacrylate), PFPE (Perfluoropolyether), PC (Polycarbonate), PTFE (Polytetrafluoroethylene), Spectralon, ETFE (Ethylene Tetra fluoro Ethylene), and PE (polyethylene), so as to reflect sunlight based on the refractive index difference of the at least one inorganic particle.

[0105] That is, the sunlight reflecting layer 111 can be formed as any one of a white reflective film composed of inorganic particles that are conducive to scattering and reflecting sunlight, a reflective film formed of at least one polymer particle, and a reflective film formed of a mixture based on at least one inorganic particle mixed in a thin film polymer.

[0106] According to this, the reflectivity is increased by using a metal or alloy material having a high reflectivity to sunlight, and a sunlight reflecting layer having excellent chemical stability is constructed, thereby improving the radiation cooling performance of the radiation cooling element.

[0107] According to an embodiment of the present invention, the radiation cooling layer 112 may include at least one layer of an inorganic layer, a polymer layer, a composite inorganic layer, and a composite polymer layer, which are included in at least one pair to form a multilayer structure, so that infrared rays within a wavelength range equivalent to the sky window can be absorbed and radiated based on the multilayer structure.

[0108] That is, the radiation cooling layer 112 is composed of multiple layers of various materials, and can achieve high infrared radiation rate in the wavelength range equivalent to the atmospheric window. For example, the radiation cooling layer 112 can also be called an infrared radiation layer.

[0109] For example, refer to Figures 2A to 5F Supplementary description: The inorganic layer and the polymer layer of the radiation cooling layer 112 form a pair of multilayer structures.

[0110] According to one embodiment of the present invention, the multilayer structure may include at least one of the four structures described below: a first structure in which the inorganic layer is laminated on the polymer layer; a second structure in which the polymer layer is laminated again after the inorganic layer is laminated on the polymer layer; and a third structure in which the polymer layer is laminated on the inorganic layer; and a fourth structure in which the inorganic layer is laminated again after the polymer layer is laminated on the inorganic layer.

[0111] As an example, the multilayer structure of the radiation cooling layer 112 may include at least one of the four repeating structures described below: a first repeating structure, in which the first structure is repeatedly laminated at least once; a second repeating structure, in which the second structure is repeatedly laminated at least once; a third repeating structure, in which the third structure is repeatedly laminated at least once; and a fourth repeating structure, in which the four structures are repeatedly laminated at least once.

[0112] The multilayer structure of the radiation cooling layer 102 according to an embodiment of the present invention may include at least one of the two structures described below: a fifth structure, in which after the inorganic layer is laminated on the polymer layer, a polymer layer based on a polymer different from the molded polymer of the polymer layer is laminated; a sixth structure, in which after the inorganic layer is laminated on the polymer layer, a polymer layer based on a polymer different from the molded polymer of the polymer layer is laminated.

[0113] As an example, the multilayer structure of the radiation cooling layer 112 may include at least one of the two repeating structures described below: a fifth repeating structure in which the fifth structure is repeatedly laminated at least once; and a sixth repeating structure in which the sixth structure is repeatedly laminated at least once.

[0114] According to an embodiment of the present invention, the multilayer structure of the radiation cooling layer 112 may include at least one of the five structures described below: a seventh structure in which the inorganic and polymer composite layers are laminated again after the inorganic layer is laminated on the inorganic and polymer composite layers; an eighth structure in which the inorganic and polymer composite layers including inorganic particles different from the inorganic particles contained in the inorganic and polymer composite layers are laminated after the inorganic layer is laminated on the inorganic and polymer composite layers; a ninth structure in which the inorganic layer is laminated on the inorganic and polymer composite layers. The tenth structure, in which after the composite inorganic layer is laminated on the polymer layer, the polymer layer is laminated again; the eleventh structure, in which after the polymer layer is laminated on the composite inorganic layer, the inorganic and polymer layers are laminated again; the eleventh structure, in which after the composite inorganic layer is laminated on the polymer layer, the polymer layer is laminated again; and the twelfth structure, in which after the inorganic layer is laminated on the composite polymer layer, the composite polymer layer is laminated again.

[0115] As an example, the multilayer structure of the radiation cooling layer 112 may include at least one of the five repeating structures described below: a seventh repeating structure, wherein the seventh structure is repeatedly laminated at least once; an eighth repeating structure, wherein the eighth structure is repeatedly laminated at least once; a ninth repeating structure, wherein the ninth structure is repeatedly laminated at least once; and a tenth repeating structure, wherein the tenth structure is repeatedly laminated at least once; an eleventh repeating structure, wherein the eleventh structure is repeatedly laminated at least once; and a twelfth repeating structure, wherein the twelfth structure is repeatedly laminated at least once.

[0116] In the above description, the multilayer structure of the radiative cooling layer 112 is exemplified as first to twelfth structures, and although the first to twelfth structures exemplify first to twelfth repeating structures, they are not limited to the corresponding structures and may be modified to more structures.

[0117] As an example, the multilayer structure performs the functions of high solar reflection and selective radiation through the refractive index of the polymer or the refractive index of the inorganic substance constructed for higher solar reflection.

[0118] For example, a multilayer structure can be made to adjust the refractive index of each layer according to the forming material, thereby having a higher selective radiation function while achieving a radiation cooling element with low absorption and high reflection of sunlight.

[0119] For example, the selective radiation function may be a function of absorbing and radiating long-wavelength infrared rays in a wavelength range corresponding to an atmospheric window.

[0120] In addition, the multilayer structure can be modified to facilitate the reflection of sunlight and the radiation and absorption of infrared light in the wavelength range corresponding to the atmospheric window by the difference in the refractive index of the polymer or inorganic material of each layer.

[0121] According to one embodiment of the present invention, the inorganic layer constituting the radiation cooling layer 112 is formed by at least one inorganic substance selected from the group consisting of Al2O3, SiO2, BaSO4, LiF, CaSO4, ZnO, TiO2, ZrO2, CaF2, MgF2, HfO2, CaCO3, AlN, MgPHO4 and Si3N4.

[0122] For example, the inorganic layer can be formed using various deposition methods such as spin coating, bar coating, dip-coating, and spray coating.

[0123] As an example, the polymer layer constituting the radiation cooling layer 112 can be formed by at least one polymer selected from the group consisting of PDMS (Polydimethyl siloxane), PUA (Poly urethane acrylate), PVDF (Polyvinylidene fluoride), PET (polyethyleneterephthalate), PVC (polyvinyl chloride), PVDF (Polyvinylidene fluoride), DPHA (Dipentaerythritol Hexaacrylate), PMMA (polymethyl methacrylate), PBMA (polymethyl methacrylate), PFPE (Perfluoropolyether), PC (Polycarbonate), PTFE (Polytetrafluoroethylene), Spectralon, ETFE (Ethylene Tetra fluoro Ethylene), and PE (polyethylene).

[0124] For example, the polymer layer may be formed by mixing each polymer and a solvent and using various deposition methods such as spin coating, bar coating, dip-coating, and spray coating.

[0125] According to an embodiment of the present invention, the inorganic and polymer composite layers constituting the radiation cooling layer 112 may be formed into a mixture, wherein the mixture includes PDMS (Polydimethyl siloxane), PUA (Poly urethane acrylate), PVDF (Polyvinylidene fluoride), PET (polyethylene terephthalate), PVC (polyvinyl chloride), PVDF (Polyvinylidene fluoride), DPHA (Dipentaerythritol Hexaacrylate), PMMA (polymethyl methacrylate), PBMA (polymethyl methacrylate), PFPE (Perfluoropolyether), PC (Polycarbonate), PTFE (Polytetrafluoroethylene), Spectralon, ETFE (Ethylene Tetra fluoro At least one of the polymers selected from the group consisting of polyethylene (ETHYLENE), polyethylene (ETHYLENE), and PE (polyethylene) contains at least one inorganic substance selected from the group consisting of Al2O3, SiO2, BaSO4, LiF, CaSO4, ZnO, TiO2, ZrO2, CaF2, MgF2, HfO2, CaCO3, AlN, MgPHO4 and Si3N4.

[0126] As an example, the composite inorganic layer of the radiation cooling layer 112 is formed by mixing a first inorganic substance selected from any one of Al2O3, SiO2, BaSO4, LiF, CaSO4, ZnO, TiO2, ZrO2, CaF2, MgF2, HfO2, CaCO3, AlN, MgPHO4 and Si3N4 and a second inorganic substance different from the first inorganic substance among Al2O3, SiO2, BaSO4, LiF, CaSO4, ZnO, TiO2, ZrO2, CaF2, MgF2, HfO2, CaCO3, AlN, MgPHO4 and Si3N4.

[0127] According to an embodiment of the present invention, the composite polymer layer constituting the radiation cooling layer 112 comprises a first polymer selected from any one of PDMS (Polydimethyl siloxane), PUA (Poly urethane acrylate), PVDF (Polyvinylidene fluoride), PET (polyethylene terephthalate), PVC (polyvinyl chloride), PVDF (Polyvinylidene fluoride), DPHA (Dipentaerythritol Hexaacrylate), PMMA (polymethyl methacrylate), PBMA (polymethyl methacrylate), PFPE (Perfluoropolyether), PC (Polycarbonate), PTFE (Polytetrafluoroethylene), Spectralon, ETFE (Ethylene Tetra fluoro Ethylene), and PE (polyethylene) and the PDMS (Polydimethyl siloxane), PDMS (Polydimethyl siloxane), PUA (Poly urethane acrylate), PVDF (Polyvinylidene fluoride), PET (polyethylene terephthalate), PVC (polyvinyl chloride), PVDF (Polyvinylidene The polymer is formed by mixing a second polymer different from the first polymer selected from the group consisting of fluoride, DPHA (Dipentaerythritol Hexaacrylate), PMMA (polymethyl methacrylate), PBMA (polymethyl methacrylate), PFPE (Perfluoropolyether), PC (Polycarbonate), PTFE (Polytetrafluoroethylene), Spectralon, ETFE (Ethylene Tetra fluoro Ethylene), and PE (polyethylene).

[0128] Accordingly, the present invention can improve the radiation cooling performance of the radiation cooling element by using a multi-layer junction radiation cooling layer composed of polymer and inorganic substances to have a maximum emissivity in a wavelength range equivalent to the atmospheric window.

[0129] FIG. 2A to FIG. 2D is a diagram showing a radiative cooling element having a multilayer structure based on polymer layers and inorganic layers according to an embodiment of the present invention.

[0130] FIG. 2A to FIG. 2D A radiative cooling element is illustrated in which the radiative cooling layer according to an embodiment of the present invention is composed of a multilayer structure of a polymer layer and an inorganic layer.

[0131] Reference Figure 2A The radiation cooling element 200 includes a substrate 201 , a sunlight reflecting layer 202 and a radiation cooling layer 203 .

[0132] The radiation cooling layer 203 according to an embodiment of the present invention may be formed into a multi-layer structure in which a polymer layer 204 is laminated on the solar reflection layer 202 , and an inorganic layer 205 is laminated on the polymer layer 204 .

[0133] As an example, the radiation cooling layer 203 may be equivalent to Figure 1A , Figure 1B The first structure described in .

[0134] According to an embodiment of the present invention, the radiation cooling layer 203 may be formed into a multilayer structure of a first repeating structure by repeatedly laminating the first structure at least once.

[0135] Reference Figure 2B The radiation cooling element 210 includes a substrate 211 , a sunlight reflecting layer 212 and a radiation cooling layer 213 .

[0136] The radiation cooling layer 213 according to the embodiment of the present invention may be formed into a multi-layer structure in which an inorganic layer 214 is laminated on the sunlight reflecting layer 212 , and a polymer layer 215 is laminated on the inorganic layer 214 .

[0137] As an example, the radiation cooling layer 213 may be equivalent to Figure 1A , Figure 1B The second structure described in .

[0138] According to an embodiment of the present invention, the radiation cooling layer 213 may be formed into a multilayer structure of a second repeating structure by repeatedly laminating the second structure at least once.

[0139] Reference Figure 2C The radiation cooling element 220 includes a substrate 221 , a sunlight reflecting layer 222 and a radiation cooling layer 223 .

[0140] The radiation cooling layer 233 according to the embodiment of the present invention may be formed into a multilayer structure in which the inorganic layer 224 is laminated on the sunlight reflecting layer 222 , the inorganic layer 224 is laminated on the polymer layer 225 , and the polymer layer 226 is laminated on the inorganic layer 225 .

[0141] Here, the polymer layer 224 and the polymer layer 226 may be formed using the same polymer.

[0142] As an example, the radiation cooling layer 223 may be equivalent to Figure 1A , Figure 1B The third structure described in .

[0143] According to an embodiment of the present invention, the radiation cooling layer 223 may be formed into a multi-layer structure of a third repetitive structure by repeatedly laminating the third structure at least once or more.

[0144] Reference Figure 2D The radiation cooling element 230 includes a substrate 231 , a sunlight reflecting layer 232 and a radiation cooling layer 233 .

[0145] The radiation cooling layer 233 according to the embodiment of the present invention may be formed into a multilayer structure in which an inorganic layer 234 is laminated on the sunlight reflecting layer 232 , a polymer layer 235 is laminated on the inorganic layer 234 , and an inorganic layer 236 is laminated on the polymer layer 235 .

[0146] Here, the inorganic layer 234 and the inorganic layer 236 may be formed using the same inorganic material or inorganic particles.

[0147] As an example, the radiation cooling layer 233 may be equivalent to Figure 1A , Figure 1B The fourth structure described in .

[0148] According to an embodiment of the present invention, the radiation cooling layer 233 may be formed into a multi-layer structure of a fourth repeating structure by repeatedly laminating the fourth structure at least once or more.

[0149] Figure 3A and Figure 3B FIG. 4 is a diagram illustrating a radiative cooling element having a multilayer structure based on at least one polymer layer and at least one inorganic layer according to an embodiment of the present invention.

[0150] Figure 3A and Figure 3B The radiative cooling element is illustrated as a multi-layer structure based on one or more polymer layers formed using one or more different types of polymers and one or more inorganic layers formed using one or more different kinds of inorganic substances or inorganic particles according to an embodiment of the present invention.

[0151] Reference Figure 3A The radiation cooling element 300 includes a substrate 301 , a sunlight reflecting layer 302 and a radiation cooling layer 303 .

[0152] In the radiation cooling layer 303 according to the embodiment of the present invention, the polymer layer 304 is laminated on the sunlight reflecting layer 302, the inorganic layer 305 is laminated on the polymer layer 304, and the polymer layer 306 is laminated on the inorganic layer 305, so that the radiation cooling layer 303 forms a multilayer structure.

[0153] Here, the polymer layer 304 and the polymer layer 306 may be formed using polymers different from each other.

[0154] As an example, the radiation cooling layer 303 may be equivalent to Figure 1A , Figure 1B The fifth structure described in .

[0155] According to an embodiment of the present invention, the radiation cooling layer 303 may be repeatedly laminated at least once with the fifth structure to have a multi-layer structure of the fifth repeating structure.

[0156] Reference Figure 3B The radiation cooling element 310 includes a substrate 311 , a sunlight reflecting layer 312 and a radiation cooling layer 313 .

[0157] In the radiation cooling layer 313 according to the embodiment of the present invention, the inorganic layer 314 is laminated on the sunlight reflecting layer 312, the polymer layer 315 is laminated on the inorganic layer 314, and the inorganic layer 316 is laminated on the polymer layer 315, so that the radiation cooling layer 313 forms a multi-layer structure.

[0158] Here, the inorganic layer 314 and the inorganic layer 316 may be formed using inorganic substances or inorganic particles different from each other.

[0159] As an example, the radiative cooling layer 313 may correspond to Figure 1A , Figure 1B The sixth structure described in .

[0160] According to an embodiment of the present invention, the radiation cooling layer 313 may be formed into a multi-layer structure having a sixth repetitive structure by repeatedly laminating the sixth structure at least once or more.

[0161] FIG. 4A to FIG. 4C is a diagram showing a radiation cooling element having a multilayer structure based on a polymer layer, an inorganic layer, a composite polymer layer, a composite inorganic layer, and an inorganic and polymer composite layer according to an embodiment of the present invention.

[0162] Reference Figure 4AThe radiation cooling element 400 includes a substrate 401 , a sunlight reflecting layer 402 and a radiation cooling layer 403 .

[0163] The radiation cooling layer 403 according to the embodiment of the present invention can be formed into a multilayer structure in which an inorganic and polymer composite layer 404 is laminated on the sunlight reflecting layer 402 , an inorganic layer 405 is laminated on the inorganic and polymer composite layer 404 , and an inorganic and polymer composite layer 406 is laminated on the inorganic layer 405 .

[0164] Here, the inorganic and polymer composite layer 404 and the inorganic and polymer composite layer 406 may be formed based on different polymers.

[0165] As an example, the radiation cooling layer 403 may be equivalent to Figure 2A , Figure 2B , Figure 2C , Figure 2D The seventh structure described in .

[0166] According to an embodiment of the present invention, the radiation cooling layer 403 may be repeatedly laminated at least once through the seventh structure to form a multilayer structure of the seventh repeating structure.

[0167] For example, the inorganic and polymer composite layer 404 and the inorganic and polymer composite layer 406 may be formed by including different inorganic particles. In this case, the inorganic and polymer composite layer 404 and the inorganic and polymer composite layer 406 may be formed by including different inorganic particles. Figure 2A , Figure 2B , Figure 2C , Figure 2D The eighth structure shown.

[0168] In addition, the eighth structure of the radiation cooling layer 403 may also be formed into a multilayer structure of the eighth repeating structure by repeatedly laminating at least once.

[0169] Reference Figure 4B The radiation cooling element 410 includes a substrate 411 , a sunlight reflecting layer 412 and a radiation cooling layer 413 .

[0170] The radiation cooling layer 413 according to the embodiment of the present invention is formed into a multilayer structure in which a composite inorganic layer 414 is laminated on the sunlight reflecting layer 412 , a polymer layer 415 is laminated on the composite inorganic layer 414 , and an inorganic and polymer composite layer 416 is laminated on the polymer layer 415 .

[0171] Here, the composite inorganic material layer 414 may be formed using first and second inorganic materials that are different inorganic materials from each other or first and second inorganic particles.

[0172] In addition, the inorganic and polymer composite layer 416 may be formed using the polymer forming the polymer layer 415 and the second inorganic or second inorganic particles forming the composite inorganic layer 414 .

[0173] According to an embodiment of the present invention, the radiation cooling layer 413 may be equivalent to Figure 2A , Figure 2B , Figure 2C , Figure 2D The tenth structure described in .

[0174] In addition, the radiation cooling layer 413 may be repeatedly laminated at least once through the tenth structure to form a multilayer structure of the tenth repeating structure.

[0175] According to an embodiment of the present invention, the radiation cooling layer 413 can be modified to be: Figure 2A , Figure 2B , Figure 2C , Figure 2D The ninth structure and the eleventh structure described in .

[0176] In addition, the radiation cooling layer 413 may be formed into a multilayer structure of a ninth repetitive structure by repeatedly laminating the ninth structure at least once, and may be formed into a multilayer structure of an eleventh repetitive structure by repeatedly laminating the eleventh structure at least once.

[0177] Reference Figure 4C The radiation cooling element 210 includes a substrate 421 , a sunlight reflecting layer 422 and a radiation cooling layer 423 .

[0178] The radiation cooling layer 423 according to the embodiment of the present invention may be formed into a multilayer structure in which a composite polymer layer 424 is laminated on the sunlight reflecting layer 422 , an inorganic layer 425 is laminated on the composite polymer layer 424 , and a composite polymer layer 426 is laminated on the inorganic layer 425 .

[0179] Here, the composite polymer layer 424 may be formed using a first polymer and a second polymer that are different polymers.

[0180] According to an embodiment of the present invention, the radiation cooling layer 423 may be equivalent to Figure 2A , Figure 2B , Figure 2C , Figure 2D The twelfth structure described in .

[0181] In addition, the radiation cooling layer 423 may also be formed into a multilayer structure of the twelfth repeating structure by repeatedly laminating the twelfth structure at least once or more.

[0182] FIG. 5A to FIG. 5F FIG. 1 is a diagram for explaining an electron microscope image of a multi-layered radiation cooling element according to an embodiment of the present invention.

[0183] Figure 5A and Figure 5B Electron microscope images and laminate structures are illustrated for describing radiative cooling elements based on polymer layers laminated as a single layer.

[0184] Reference Figure 5A and Figure 5B , the radiation cooling element 500 includes a substrate 501 , a sunlight reflecting layer 502 and a polymer layer 503 .

[0185] As an example, the sunlight reflecting layer 502 may be formed of silver (Ag) as a metal material, and the polymer layer 503 may be formed of DPHA as a polymer.

[0186] Figure 5C and Figure 5D An electron microscope image and a laminated structure are illustrated for describing a radiation cooling element based on a polymer layer and an inorganic layer laminated into three layers.

[0187] Reference Figure 5C and Figure 5D The radiation cooling element 510 includes a substrate 511 , a sunlight reflecting layer 512 , a polymer layer 513 , an inorganic layer 514 and a polymer layer 515 .

[0188] As an example, the sunlight reflecting layer 512 can be formed of silver (Ag) as a metal material, the polymer layer 513 and the polymer layer 515 can be formed of DPHA as a polymer, and the inorganic layer 514 can be formed of Al2O3 as an inorganic substance or inorganic particles.

[0189] Figure 5E and Fig. 5F An electron microscope image and a laminated structure are shown for describing a radiative cooling element based on a four-layer stack of polymer and inorganic layers.

[0190] Reference Figure 5E and Fig. 5F The radiation cooling element 520 includes a substrate 521 , a sunlight reflecting layer 522 , a polymer layer 523 , an inorganic layer 524 , a polymer layer 525 and an inorganic layer 526 .

[0191] As an example, the sunlight reflecting layer 522 is formed of silver (Ag) as a metal material, the polymer layer 523 and the polymer layer 525 are formed of DPHA as a polymer, and the inorganic layer 524 and the inorganic layer 526 are formed of an inorganic substance or it can be formed of inorganic particles of Al2O3.

[0192] FIG. 6A to FIG. 6C FIG. 5 is a graph showing the optical characteristics of a multi-layered radiation cooling element according to an embodiment of the present invention.

[0193] FIG. 6A to FIG. 6C The simulation results of various examples of a radiative cooling element formed of a multilayer structure according to an embodiment of the present invention are compared.

[0194] Reference Fig. 6A A graph 600 is provided showing the absorptivity and emissivity of four radiative cooling elements described below as they vary with the wavelength range of sunlight, the four radiative cooling elements being as follows: a first radiative cooling element, which is composed of a DPHA-based polymer layer; a second radiative cooling element, which has an inorganic layer based on Al2O3 nanoparticles (NP) additionally laminated on the first radiative cooling element; a third radiative cooling element, which has a DPHA-based polymer layer additionally laminated on the second radiative cooling element; and a fourth radiative cooling element, which has an inorganic layer based on Al2O3 nanoparticles (NP) additionally laminated on the third radiative cooling element.

[0195] The first to fourth radiative cooling elements include a substrate composed of silicon and silver.

[0196] Reference Figure 6B A graph 610 is shown showing the net cooling power as a function of the ambient temperature in first to fourth radiative cooling elements.

[0197] Reference Figure 6C A graph 620 is shown showing the net cooling power at first to fourth radiative cooling elements as a function of ambient temperature.

[0198] The average absorptivity, average emissivity, total cooling power and cooling temperature of the first to fourth radiative cooling elements are summarized in Table 1 below.

[0199]

Table 1

[0200]

[0201] Referring to Table 1, in the case where the radiation cooling layer is designed to have a multi-layer structure by additionally laminating a polymer layer and an inorganic layer, the average emissivity can be increased and also excellent in cooling power and cooling temperature.

[0202] Accordingly, the present invention uses a multi-layered radiative cooling layer composed of polymer and inorganic substances to have a maximum emissivity in a wavelength range equivalent to the atmospheric window, thereby improving the radiative cooling performance of the radiative cooling element.

[0203] In addition, the present invention improves the reflectivity by using a metal or alloy material having high reflectivity to sunlight and constructs a sunlight reflecting layer having excellent chemical stability, thereby improving the radiation cooling performance of the radiation cooling element.

[0204] In the above specific embodiments, the constituent elements included in the invention are expressed in the singular or plural according to the specific embodiments suggested.

[0205] However, the singular or plural expression is a choice made for the convenience of description in accordance with the circumstances. The above embodiments are not limited to singular or plural constituent elements. Even if there are plural constituent elements, they can also be singular, and even if there are plural constituent elements, they can also be plural.

[0206] On the other hand, although specific embodiments have been described in the description of the present invention, various modifications may be made without departing from the scope of the technical spirit contained in each embodiment.

[0207] Therefore, the scope of the present invention should not be limited to the described embodiments, and should be determined by the claims, their equivalents, and claims described later.

Claims

1. A radiation cooling element, characterized in that: include: A multilayer structure formed by including at least one layer of an inorganic layer, a polymer layer, a composite inorganic layer, a composite polymer layer, and a composite layer of an inorganic layer and a polymer in at least one pair, and The multilayer structure includes a radiation cooling layer that absorbs and radiates infrared light in a wavelength range equivalent to the atmospheric window while reflecting sunlight. The multilayer structure includes at least one of the following structures: a first structure in which the inorganic material is laminated on the polymer layer; a second structure in which the polymer layer is laminated again after the inorganic material is laminated on the polymer layer; a third structure in which the polymer is laminated on the inorganic material layer; and a fourth structure in which the inorganic material layer is laminated again after the polymer is laminated on the inorganic material layer. wherein the multilayer structure increases the average emissivity, cooling power and cooling temperature in a wavelength range equivalent to the atmospheric window based on the lamination of the inorganic layer and the polymer layer, Wherein, the multilayer structure includes: a first repeating structure, wherein the first structure is repeatedly laminated at least once; a second repeating structure, wherein the second structure is repeatedly laminated at least once; a third repeating structure, wherein the third structure is repeatedly laminated at least once; a fourth repeating structure, wherein the fourth structure is repeatedly laminated at least once; a fifth structure, wherein after the inorganic layer is laminated on the polymer layer, a polymer layer based on a polymer different from the molding polymer of the polymer layer is laminated; a sixth structure, wherein after the polymer is laminated on the inorganic layer, a polymer layer based on a polymer different from the molding polymer of the polymer layer is laminated; a seventh structure, wherein after the inorganic layer is laminated on the inorganic and polymer composite layer, the inorganic and polymer composite layer is laminated again; an eighth structure, wherein the inorganic layer is laminated on the inorganic and polymer composite layer Thereafter, an inorganic and polymer composite layer including inorganic particles different from the inorganic particles contained in the inorganic and polymer composite layer is laminated; a ninth structure, in which after the inorganic layer is laminated on the inorganic and polymer composite layer, an inorganic and polymer composite layer based on a polymer different from a forming polymer of the inorganic and polymer composite layer is laminated; a tenth structure, in which after the composite inorganic layer is laminated on the polymer layer, the polymer layer is laminated again; an eleventh structure, in which after the polymer is laminated on the composite inorganic layer, the inorganic and polymer composite layer is laminated again; an eleventh structure, in which after the composite inorganic layer is laminated on the polymer layer, the polymer layer is laminated again; and a twelfth structure, in which after the inorganic layer is laminated on the composite polymer layer, the composite polymer layer is laminated again.

2. The radiative cooling element according to claim 1, characterized in that The inorganic layer is formed of at least one inorganic substance selected from the group consisting of Al2O3, SiO2, BaSO4, LiF, CaSO4, ZnO, TiO2, ZrO2, CaF2, MgF2, HfO2, CaCO3, AlN, MgPHO4 and Si3N4.

3. The radiative cooling element according to claim 1, characterized in that The polymer layer is formed of at least one polymer selected from the group consisting of PDMS, PUA, PVDF, PET, PVC, DPHA, PMMA, PBMA, PFPE, PC, PTFE, Spectralon, ETFE, and PE.

4. The radiative cooling element according to claim 1, characterized in that The inorganic and polymer composite layer is formed by a mixture, which includes at least one polymer selected from the group consisting of PDMS, PUA, PVDF, PET, PVC, DPHA, PMMA, PBMA, PFPE, PC, PTFE, Spectralon, ETFE and PE, and at least one inorganic selected from the group consisting of Al2O3, SiO2, BaSO4, LiF, CaSO4, ZnO, TiO2, ZrO2, CaF2, MgF2, HfO2, CaCO3, AlN, MgPHO4 and Si3N4.

5. The radiative cooling element according to claim 1, characterized in that The composite inorganic layer is formed by mixing a first inorganic selected from Al2O3, SiO2, BaSO4, LiF, CaSO4, ZnO, TiO2, ZrO2, CaF2, MgF2, HfO2, CaCO3, AlN, MgPHO4 and Si3N4 and a second inorganic selected from Al2O3, SiO2, BaSO4, LiF, CaSO4, ZnO, TiO2, ZrO2, CaF2, MgF2, HfO2, CaCO3, AlN, MgPHO4 and Si3N4, and the second inorganic is different from the first inorganic.

6. The radiative cooling element according to claim 1, characterized in that The composite polymer layer is formed by mixing a first polymer selected from PDMS, PUA, PVDF, PET, PVC, DPHA, PMMA, PBMA, PFPE, PC, PTFE, Spectralon, ETFE and PE and a second polymer selected from PDMS, PUA, PVDF, PET, PVC, DPHA, PMMA, PBMA, PFPE, PC, PTFE, Spectralon, ETFE and PE, wherein the second polymer is different from the first polymer.

7. The radiative cooling element according to claim 1, characterized in that The invention also includes a sunlight reflecting layer formed of at least one of a metal material, at least one inorganic particle and a polymer including the inorganic particle, so as to reflect sunlight.

8. The radiative cooling element according to claim 7, characterized in that The sunlight reflecting layer is formed of at least one metal material selected from silver, aluminum, gold, copper, titanium, chromium, manganese, iron and platinum, or any one of at least two alloy materials combined therein.

9. The radiative cooling element according to claim 7, characterized in that The sunlight reflecting layer is formed of at least one inorganic particle selected from the group consisting of MgF2, Al2O3, SiO2, MgO, ZnO, CaCO3, AlN, MgPHO4 and TiO2, or a polymer comprising the inorganic particles, wherein the polymer comprises at least one selected from the group consisting of PDMS, PUA, PVDF, PET, PVC, DPHA, PMMA, PBMA, PFPE, PC, PTFE, Spectralon, ETFE and PE, The sunlight reflecting layer reflects sunlight based on the refractive index difference of the inorganic particles.

10. The radiative cooling element according to claim 1, characterized in that The multi-layer structure includes at least one of the following repeating structures: a fifth repeating structure, the fifth structure of which is repeatedly laminated at least once; and a sixth repeating structure, the sixth structure of which is repeatedly laminated at least once.

11. The radiative cooling element according to claim 1, characterized in that The multilayer structure includes at least one of the following repeating structures: a seventh repeating structure, wherein the seventh structure is repeatedly laminated at least once; an eighth repeating structure, wherein the eighth structure is repeatedly laminated at least once; a ninth repeating structure, wherein the ninth structure is repeatedly laminated at least once; and a tenth repeating structure, wherein the tenth structure is repeatedly laminated at least once; an eleventh repeating structure, wherein the eleventh structure is repeatedly laminated at least once; and a twelfth repeating structure, wherein the twelfth structure is repeatedly laminated at least once.

Images