Energy-saving ceramic coating with radiation energy regulation and conversion functions as well as preparation method and application of energy-saving ceramic coating

Abstract

The invention belongs to the technical field of radiation cold-heat conversion films, and particularly relates to an energy-saving ceramic coating with radiation energy regulation and conversion functions as well as a preparation method and application of the energy-saving ceramic coating. The method comprises the following steps: 1) preparing a semi-viscous SMMA prepolymer dispersion liquid; 2) preparing ethanol dispersion liquid of alpha-aluminum oxide; and 3) mixing the SMMA prepolymer dispersion liquid with the ethanol dispersion liquid of alpha-aluminum oxide, carrying out ultrasonic treatment, and then fully stirring to obtain a white ceramic coating, namely the energy-saving ceramic coating with the radiation energy regulation and conversion functions. A coating prepared from the energy-saving ceramic coating provided by the invention has the characteristics of high solar reflectivity, high atmospheric transmission window emissivity, high mechanical strength, low thickness and the like.

Description

Technical Field

[0001] The present invention belongs to the technical field of radiation heat and cold conversion films, and in particular relates to an energy-saving ceramic coating with radiation energy regulation and conversion functions, and a preparation method and application thereof. Background Art

[0002] As an emerging cooling technology, Passive Daytime Radiant Cooling (PDRC) uses the atmospheric window (ATW, 8-13μm) to transfer surface heat to outer space at -270℃ through radiation heat exchange, and reduces heat absorption by enhancing the reflectivity of the solar spectrum (0.3-2.5μm). It can achieve temperature reduction without consuming any energy and can be widely used in zero-energy buildings, solar cells, outdoor power equipment and other scenarios.

[0003] Radiative cooling paint is an innovative type of paint designed to reflect sunlight and emit infrared radiation, thereby reducing the temperature of the surface it is applied to. The paint works by reflecting most of the sun's rays, including visible and ultraviolet light, while emitting heat in the form of infrared radiation. This dual action allows surfaces coated with radiative cooling paint to remain cooler than their surroundings, even in direct sunlight. The technology has potential applications in reducing the need for air conditioning in buildings, helping to improve energy efficiency and mitigate the urban heat island effect.

[0004] However, the existing radiative cooling coatings generally have a reflectivity of less than 90% for sunlight and an emissivity of an atmospheric transmission window, which results in poor temperature control effects. In addition, the existing radiative cooling coatings also have disadvantages such as complex preparation processes, low mechanical strength, poor weather resistance, and high costs. Therefore, there is an urgent need to develop a new type of high-efficiency radiative cooling coating. Summary of the invention

[0005] In order to address the deficiencies of the prior art, the present invention provides an energy-saving ceramic coating with radiation energy regulation and conversion functions, and a preparation method and application thereof. The coating prepared with the energy-saving ceramic coating provided by the present invention has the characteristics of high solar reflectivity, high atmospheric transmission window emissivity, high mechanical strength and low thickness. The coating can provide passive energy regulation without the use of mechanical refrigeration equipment. The coating reflects solar radiation and emits thermal radiation to the cold outer space, thereby realizing spontaneous energy regulation and conversion without electricity. The resulting building coating can realize indoor heat and temperature regulation of the building, which can reduce 20% of cooling electricity and achieve energy saving.

[0006] The technical solution provided by the present invention is as follows:

[0007] A method for preparing an energy-saving ceramic coating having the function of regulating and converting radiation energy comprises the following steps:

[0008] 1) adding styrene dimethyl methacrylate copolymer (SMMA) to an acetone solution, stirring under ultrasound until completely dissolved, and then heating to remove the acetone to obtain a semi-viscous SMMA prepolymer dispersion;

[0009] 2) adding α-alumina powder to an ethanol solution and dispersing the powder by ultrasonication to obtain an ethanol dispersion of α-alumina;

[0010] 3) The SMMA prepolymer dispersion is mixed with the ethanol dispersion of α-alumina, subjected to ultrasound, and then fully stirred to obtain a white ceramic coating, which is an energy-saving ceramic coating with radiation energy regulation and conversion functions.

[0011] The energy-saving ceramic coating obtained by the above technical solution can be conveniently used to prepare a coating having high reflectivity within the atmospheric window transmittance range of any thickness, making it suitable for coating concrete and similar substrates.

[0012] The molecular weight of the SMMA polymer is usually between several thousand and hundreds of thousands. Preferably, the molecular weight of the SMMA polymer is 12,000 and can be purchased from Aladdin Reagent Company.

[0013] The mass ratio of the SMMA polymer to acetone is 1:(5-30), preferably, the mass ratio is 1:15.

[0014] The α-alumina powder has an average particle size of 25-2000 nm, preferably, an average particle size of 120 nm, and can be purchased from Sinopharm Reagent Company.

[0015] In the ethanol dispersion of α-alumina, the mass ratio of α-alumina to ethanol is 1:(20-50), preferably, the mass ratio is 1:30.

[0016] The mass ratio of the SMMA prepolymer dispersion to the ethanol dispersion of α-alumina is 1:(5-10), preferably, the mass ratio is 1:7.

[0017] The present invention also provides an energy-saving ceramic coating with radiation energy regulation and conversion functions prepared by the above preparation method.

[0018] The invention also provides application of energy-saving ceramic coating for manufacturing building exterior walls.

[0019] The application of energy-saving ceramic coatings specifically includes the following steps: after applying the energy-saving ceramic coatings on the concrete exterior wall or roof of a building, wait for the solvent to evaporate completely naturally under outdoor temperature conditions, thus forming an energy-saving ceramic coating layer on the surface of the concrete exterior wall or roof of the building.

[0020] Based on the above technical solution:

[0021] The resulting energy-saving ceramic coating layer has sub-ambient cooling performance. Even at noon, the coating can achieve more than 5°C below-ambient cooling, which is cooler than white commercial tiles.

[0022] The resulting energy-saving ceramic coating is resistant to environmental irritants, the coating resists pollutants when treated with fluorosilane, maintaining solar reflectivity above 97%. The coating also resists UV radiation and fire;

[0023] When the thickness of the energy-saving ceramic coating layer is greater than or equal to 160 μm, the solar reflectivity of the energy-saving ceramic coating layer is greater than or equal to 97%, and the atmospheric transmission window emissivity is greater than or equal to 95%. Based on this, a temperature lower than 7.2°C can be achieved, while existing high-performance roof cooling coatings usually require a thickness greater than 2 mm;

[0024] When the thickness of the energy-saving ceramic coating layer is greater than or equal to 160 μm, the compressive strength of the energy-saving ceramic coating layer is greater than or equal to 140 MPa, which is much higher than the requirement of 35 MPa for building envelope structures.

[0025] Compared with the prior art, the technical solution of the present invention can achieve the following beneficial effects:

[0026] 1) The coating has the characteristics of high solar reflectivity, high mechanical strength, low thickness and low cost.

[0027] 2) Radiative coatings can provide passive cooling without the use of mechanical refrigeration equipment. These coatings reflect solar radiation and emit thermal radiation to the cold outer space, thereby achieving self-cooling without electricity.

[0028] 3) The building coating prepared by this method can realize indoor heat and temperature control of the building, and can reduce cooling power by about 20%, thereby achieving energy saving. DETAILED DESCRIPTION

[0029] The principles and features of the present invention are described below. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0030] Unless otherwise specified, the test methods used in the embodiments of the present invention are all conventional methods; the materials, reagents, etc. used are reagents and materials that can be obtained from commercial channels unless otherwise specified.

[0031] Example 1

[0032] Add styrene dimethyl methacrylate copolymer (SMMA) polymer to acetone solution, stir under ultrasound to completely dissolve it, then heat to remove excess acetone to obtain a semi-viscous SMMA prepolymer dispersion for use. Then, add α-alumina powder to ethanol solution and disperse it under ultrasound for use. Subsequently, mix the SMMA prepolymer dispersion with the ethanol dispersion of α-alumina, ultrasound for 30 minutes, and stir thoroughly to obtain a white ceramic coating. After applying the coating to the concrete exterior wall or roof of the building, the solvent completely evaporates in about 1 hour at an outdoor temperature of 30°C to form an energy-saving ceramic coating layer.

[0033] The mass ratio of SMMA polymer to acetone was 1:15.

[0034] The average particle size of α-alumina powder is 120nm.

[0035] The mass ratio of α-alumina to ethanol is 1:30.

[0036] The mass ratio of the SMMA prepolymer dispersion to the ethanol dispersion of α-alumina is 1:7.

[0037] The thickness of energy-saving ceramic coating is 160μm.

[0038] After testing, the results are as follows:

[0039] Solar reflectivity is 97%;

[0040] The atmospheric transmission window emissivity is 95%;

[0041] When the ambient temperature is 35℃, the surface of the coating layer is 7.2℃ lower than the ambient temperature.

[0042] Example 2

[0043] Add styrene dimethyl methacrylate copolymer (SMMA) polymer to acetone solution, stir under ultrasound to completely dissolve it, then heat to remove excess acetone to obtain a semi-viscous SMMA prepolymer dispersion for use. Then, add α-alumina powder to ethanol solution and disperse it under ultrasound for use. Subsequently, mix the SMMA prepolymer dispersion with the ethanol dispersion of α-alumina, ultrasound for 30 minutes, and stir thoroughly to obtain a white ceramic coating. After applying the coating to the concrete exterior wall or roof of the building, the solvent completely evaporates in about 1 hour at an outdoor temperature of 30°C to form an energy-saving ceramic coating layer.

[0044] The mass ratio of SMMA polymer to acetone was 1:15.

[0045] The average particle size of α-alumina powder is 120nm.

[0046] The mass ratio of α-alumina to ethanol is 1:30.

[0047] The mass ratio of the SMMA prepolymer dispersion to the ethanol dispersion of α-alumina is 1:7.

[0048] The thickness of energy-saving ceramic coating is 50μm.

[0049] After testing, the results are as follows:

[0050] Solar reflectivity is 90%;

[0051] The atmospheric transmission window emissivity is 87%;

[0052] When the ambient temperature is 35℃, the surface of the coating layer is 4.2℃ lower than the ambient temperature.

[0053] Example 3

[0054] Add styrene dimethyl methacrylate copolymer (SMMA) polymer to acetone solution, stir under ultrasound to completely dissolve it, then heat to remove excess acetone to obtain a semi-viscous SMMA prepolymer dispersion for use. Then, add α-alumina powder to ethanol solution and disperse it under ultrasound for use. Subsequently, mix the SMMA prepolymer dispersion with the ethanol dispersion of α-alumina, ultrasound for 30 minutes, and stir thoroughly to obtain a white ceramic coating. After applying the coating to the concrete exterior wall or roof of the building, the solvent completely evaporates in about 1 hour at an outdoor temperature of 30°C to form an energy-saving ceramic coating layer.

[0055] The mass ratio of SMMA polymer to acetone was 1:15.

[0056] The average particle size of α-alumina powder is 2000nm.

[0057] The mass ratio of α-alumina to ethanol is 1:30.

[0058] The mass ratio of the SMMA prepolymer dispersion to the ethanol dispersion of α-alumina is 1:7.

[0059] The thickness of energy-saving ceramic coating is 160μm.

[0060] After testing, the results are as follows:

[0061] Solar reflectivity is 94%;

[0062] The atmospheric transmission window emissivity is 93%;

[0063] When the ambient temperature is 35℃, the surface of the coating layer is 5.0℃ lower than the ambient temperature.

[0064] Comparative Example 1

[0065] Refer to Example 1, except that the styrene dimethyl methacrylate copolymer is replaced by PMMA with a molecular weight of 12,000.

[0066] After testing, the results are as follows:

[0067] Solar reflectivity is 84%;

[0068] The atmospheric transmission window emissivity is 88%;

[0069] When the ambient temperature is 35℃, the surface of the coating layer is 3.1℃ lower than the ambient temperature.

[0070] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing an energy-saving ceramic coating having the function of regulating and converting radiation energy, characterized in that: The following steps are involved: 1) adding styrene dimethyl methacrylate copolymer to an acetone solution, stirring under ultrasound until completely dissolved, and then heating to remove acetone to obtain a semi-viscous SMMA prepolymer dispersion; 2) adding α-alumina powder to an ethanol solution and dispersing the powder by ultrasonication to obtain an ethanol dispersion of α-alumina; 3) The SMMA prepolymer dispersion is mixed with the ethanol dispersion of α-alumina, subjected to ultrasound, and then fully stirred to obtain a white ceramic coating, which is an energy-saving ceramic coating with radiation energy regulation and conversion functions.

2. The method for preparing the energy-saving ceramic coating with radiation energy regulation and conversion function according to claim 1, characterized in that: In step 1), the mass ratio of styrene dimethyl methacrylate copolymer to acetone is 1:(5-30).

3. The method for preparing the energy-saving ceramic coating with radiation energy regulation and conversion function according to claim 1, characterized in that: In step 2), the average particle size of the α-alumina powder is 25-2000 nm.

4. The method for preparing the energy-saving ceramic coating with radiation energy regulation and conversion function according to claim 3, characterized in that: The mass ratio of α-alumina to ethanol is 1:(20-50).

5. The method for preparing the energy-saving ceramic coating with radiation energy regulation and conversion function according to claim 1, characterized in that: In step 3), the mass ratio of the SMMA prepolymer dispersion to the ethanol dispersion of α-alumina is 1:(5-10).

6. An energy-saving ceramic coating with radiation energy regulation and conversion function prepared according to the preparation method according to any one of claims 1 to 5.

7. An application of the energy-saving ceramic coating according to claim 6, characterized in that: Used to make building exterior walls.

8. The use according to claim 7, characterized in that: The method comprises the following steps: applying the energy-saving ceramic coating to the concrete outer wall or roof of the building, and then allowing the solvent to evaporate completely under outdoor temperature conditions, thereby forming an energy-saving ceramic coating layer on the surface of the concrete outer wall or roof of the building.

9. The use according to claim 8, characterized in that: When the thickness of the energy-saving ceramic coating layer is greater than or equal to 160 μm, the solar reflectivity of the energy-saving ceramic coating layer is greater than or equal to 97%, and the atmospheric transmission window emissivity is greater than or equal to 95%.

10. The use according to claim 8, characterized in that: When the thickness of the energy-saving ceramic coating layer is greater than or equal to 160 μm, the compressive strength of the energy-saving ceramic coating layer is greater than or equal to 140 MPa.