A full-day self-adaptive heating and heat preservation integrated coating material

Abstract

The application discloses a kind of all-day self-adapting heating and heat preservation integrated coating materials, belong to energy technical field.The coating includes substrate absorption layer, comprehensive layer, phase change layer and antireflection layer from bottom to top, wherein phase change layer has the function of adjusting spectral selectivity.During the day, integrated coating has high absorption in solar band, and has low emissivity in whole atmospheric band, so as to achieve heating effect.At night, integrated coating shows high reflectivity in atmospheric transparent band but high absorption in atmospheric radiation band, which can passively inhibit the thermal radiation of object, while actively using the thermal radiation of atmosphere to achieve heat preservation effect.The coating material of the application can achieve optimal thermal equilibrium state by controlling its reflectivity and emissivity in different wavelength ranges, and can be used for heating and heat preservation of buildings, vehicles, equipment, crops and the like, with the advantages of energy saving, environmental protection and sustainability.

Description

Technical Field

[0001] This invention belongs to the field of energy technology, specifically involving the integrated application of solar thermal, radiative cooling, and spectrally selective variable energy. Background Technology

[0002] Buildings, vehicles, equipment, and crops require appropriate heating or insulation during winter and in cold climates to ensure their normal operation and growth. For example, excessively low temperatures can damage plants, reducing crop yields, and can also cause frost and ice formation on power lines, posing a safety hazard to energy supply. Currently, heating and insulation have become a critical issue in many cold regions. However, traditional heating or insulation methods typically consume large amounts of energy, such as electricity and fuel, resulting in resource waste and environmental pollution. While passive methods offer energy-friendly alternatives, their effectiveness is limited. Therefore, passive heating and insulation technologies utilizing solar energy and atmospheric radiation are of significant importance and value.

[0003] Solar energy is a clean and renewable energy source that can achieve daytime heating by absorbing solar radiation. Atmospheric radiation is also a ubiquitous energy source, and its reflectivity and absorptivity can be adjusted to achieve optimal heat preservation. Currently, some researchers have developed passive heating and heat preservation technologies utilizing solar energy and atmospheric radiation. These technologies typically employ materials or structures with specific spectral selectivity, such as microstructured materials, polymer materials, nanoparticle suspensions, and thin film materials, to regulate solar or atmospheric radiation. In 2018, Li Dexin invented a solar energy collector and heat preservation material panel that effectively utilizes solar energy through a light-absorbing layer, providing excellent heat preservation and convenience for users. In 2022, Xu Lei invented a polymer infrared absorption heat preservation film for agricultural applications. By reducing infrared absorption, it effectively avoids the problem of greenhouse temperature drops caused by thermal radiation, allowing crops to grow normally during cold nights. Subsequently, in 2023, Zhang Min et al. invented a similar far-infrared heat-insulating composite polyester film. Through material structure design, they endowed the film with heat-insulating function and made it soft, durable, and broadened its application range. However, these technologies still have some shortcomings. The complex preparation process, high cost, and limited functionality, as well as the inability to switch states, are significant drawbacks. Summary of the Invention

[0004] To achieve passive heating and insulation from solar energy and atmospheric radiation, this invention provides an integrated coating material for all-day adaptive heating and insulation.

[0005] A coating material for all-day adaptive heating and heat preservation includes, from bottom to top, a base absorption layer, a composite layer, a phase change layer and an anti-reflection layer;

[0006] The material of the substrate absorption layer is either aluminum oxide or silicon dioxide;

[0007] The composite layer material is a photonic crystal film material, which is composed of two media materials with different refractive indices stacked alternately in a periodic structure;

[0008] The two media materials with different refractive indices consist of a high-refractive-index material layer and a low-refractive-index material layer, forming a structural unit containing 3 to 5 sequentially connected units; the high-refractive-index material layer is connected to the substrate absorption layer, and the low-refractive-index material layer is connected to the phase change layer.

[0009] The phase change layer material is a material with thermally induced phase change characteristics, which can change from a high transmittance state to a high reflectance state in the entire infrared band before and after the phase change.

[0010] The antireflective layer material is a material with a refractive index of less than 2 at a wavelength of 0.5 μm;

[0011] During the day, the coating material has an average absorptivity greater than 0.6 in the visible light band and an average emissivity less than 0.2 in the entire infrared band, thus achieving the heating mode.

[0012] At night, the coating material has an average emissivity greater than 0.55 in the 5–8 μm and 14–20 μm atmospheric radiation bands, and an average emissivity less than 0.35 in the 8–14 μm atmospheric transparent band, thus achieving the heat preservation mode.

[0013] The further defined technical solution is as follows:

[0014] The thickness of the substrate absorption layer is 100–500 μm.

[0015] The composite layer can produce selective strong reflection characteristics, forming a distributed Bragg reflector in the 8-14μm atmospheric transparent band, and is transparent in the remaining 5-8μm and 14-20μm atmospheric radiation bands.

[0016] The composite layer has 6 to 10 layers and a total thickness of 3 μm to 15 μm.

[0017] The phase change layer is made of vanadium dioxide and has a thickness of 200 nm.

[0018] The antireflective layer is made of aluminum oxide and has a thickness of 50–150 nm.

[0019] The high refractive index material and the low refractive index material are germanium and zinc sulfide, or silicon and zinc sulfide, or germanium and zinc oxide, or silicon and titanium dioxide, or germanium and magnesium fluoride, respectively.

[0020] The beneficial technical effects of this invention are reflected in the following aspects:

[0021] 1. The heating and heat preservation integrated coating material designed in this invention, see [link to relevant documentation]. Figure 3 In section A, during the day, the coating temperature is higher than the phase transition temperature of vanadium dioxide. Its absorptivity in the visible light band is greater than 0.6, and its average emissivity in the entire infrared band is less than 0.2, suppressing infrared radiation. This coating exhibits the high infrared reflectivity of a phase transition layer and the high visible light absorption of the overall coating, thus achieving a heating effect during the day. (See also...) Figure 3 In section B, at night, the coating temperature is below the phase transition temperature of vanadium dioxide. Vanadium dioxide is in a low-temperature, high-transmittance infrared state, with an average emissivity of less than 0.35 in the 8–14 μm infrared band and greater than 0.55 in the remaining atmospheric radiation bands of 5–8 μm and 14–20 μm. This coating reflects the spectral characteristics of both the composite layer and the base layer. The composite layer, composed of two media materials with different refractive indices stacked in a periodic structure, can form a distributed Bragg reflector in the atmospheric transparent band, reducing the emissivity in the 8–14 μm band and thus reducing heat loss. The base layer is a high-absorbency material that can effectively absorb atmospheric radiant heat in the other 5–8 μm and 14–20 μm infrared bands, thereby improving the coating's nighttime heat preservation effect. This invention, through careful adjustment of the thickness of the composite absorption layer and the antireflection layer, maximizes the reflection peak intensity and visible light absorption intensity of the designed coating material under the same conditions. In the integrated absorption layer design, the optical thickness of both dielectric layers is 1 / 4 of the designed reflection peak center wavelength, and the optical thickness is the product of the film layer thickness and the refractive index of the corresponding film material. The thickness of the antireflection layer should be 1 / 4 of the wavelength of light in the thin film medium, thus canceling out the two reflected rays. Therefore, the thickness of the antireflection film is d = λ / 4n, where n is the refractive index of the film and λ is the wavelength of light in air. However, due to the different materials used in each embodiment, this invention appropriately adjusts the thickness of each layer to balance the dual-band modulation capability of the visible and infrared bands, enabling the coating to achieve integrated heating and heat preservation functions under different temperature and illumination conditions, demonstrating innovation and practicality.

[0022] 2. This invention utilizes the thermally induced phase change properties of vanadium dioxide to achieve automatic adjustment of the spectral characteristics of the coating material according to diurnal temperature variations. It can be applied to temperature regulation in agriculture, building insulation, and electronic products. This coating material combines passive heating and insulation methods without requiring additional energy input and can switch between heating and insulation states as needed, providing a new approach to sustainable thermal management. Therefore, it has considerable potential in addressing climate change challenges and promoting carbon neutrality, contributing to energy conservation and emission reduction.

[0023] 3. By setting an anti-reflective layer, this invention improves the absorption rate of the coating material in the 0.3-2.5μm solar radiation band, which is beneficial to improving the heat preservation effect during the day. At the same time, it avoids the damage of sunlight to the phase change layer, ensuring its stability during use, and further improving the economic applicability of the coating material. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the overall structure of the coating material of the present invention;

[0025] Figure 2 This is a schematic diagram of the integrated layer structure;

[0026] Figure 3 Ideal spectral diagrams of the heating and insulation integrated coating material during the day and night;

[0027] Figure 4 The image shows the spectrum of the coating material in Example 1 under heating and heat preservation modes;

[0028] Figure 5 The image shows the spectrum of the coating material in Example 2 under heating and heat preservation modes.

[0029] Figure 6 The image shows the spectra of the coating material in Example 3 under heating and heat preservation modes.

[0030] Figure 7 The image shows the spectra of the coating material in Example 4 under heating and heat preservation modes.

[0031] Figure 8 The image shows the spectra of the coating material in Example 5 under heating and heat preservation modes.

[0032] Figure 9 The image shows the spectrum of the coating material in Example 6 under heating and heat preservation modes. Detailed Implementation

[0033] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0034] Example 1

[0035] See Figure 1 A coating material for all-day adaptive heating and heat preservation includes, from bottom to top, a base absorption layer 1, a composite layer 2, a phase change layer 3, and an anti-reflection layer 4.

[0036] The substrate absorber layer 1 is aluminum oxide with a thickness of 100 μm.

[0037] See Figure 2The composite layer is composed of three units stacked in a periodic structure. Each unit is composed of two dielectric materials: germanium 21 and zinc sulfide 22. The thickness of germanium 21 is 700 nm, and the thickness of zinc sulfide 22 is 900 nm. It contains a total of 6 layers with thicknesses of 700 nm, 900 nm, 700 nm, 900 nm, 700 nm and 900 nm, respectively. The high-refractive-index material layer germanium 21 is connected to the substrate absorption layer 1, and the low-refractive-index material layer zinc sulfide 22 is connected to the phase change layer.

[0038] Phase change layer 3 is vanadium dioxide with a thickness of 200 nm.

[0039] The antireflective layer 4 is aluminum oxide with a thickness of 140 nm.

[0040] Before depositing the multilayer film, the substrate absorber layer 1 was cleaned with an ultrasonic bath for 10 minutes, and then placed in a vacuum coating equipment. The pressure in the vacuum chamber of the coating equipment was evacuated to 3.0 × 10⁻⁶. -3 After Pa, argon and oxygen were introduced, and the vacuum chamber pressure was adjusted to 1 Pa. Then, according to the designed number of layers and thickness, the composite layer 2, phase change layer 3, and antireflection layer 4 were deposited sequentially to finally obtain an all-day adaptive heating and insulation integrated coating. Throughout the deposition process, the distance between the target and the substrate was 60 cm, the substrate temperature was maintained at room temperature, and the sputtering power was maintained at 150 W. Other embodiments were consistent.

[0041] The spectral absorption / emissivity in daytime heating mode and nighttime heat preservation mode is as follows: Figure 4 As shown, during the day, when the temperature of the coating material is above its phase transition temperature, the absorptivity of the coating material in the 0.3–2.5 μm solar radiation band is 0.69, and the emissivity in the entire 5–20 μm infrared band is 0.17. At night, when the temperature of the coating material is below its phase transition temperature, the average emissivity of the coating material in the "atmospheric window" 8–14 μm band is 0.30, and the average emissivity in the 5–8 μm and 14–20 μm atmospheric radiation bands is 0.61.

[0042] Example 2

[0043] See Figure 1 and Figure 2 A coating material for all-day adaptive heating and heat preservation includes, from bottom to top, a base absorption layer 1, a composite layer 2, a phase change layer 3, and an anti-reflection layer 4.

[0044] The substrate absorber layer 1 is aluminum oxide with a thickness of 200 μm.

[0045] The composite layer is composed of three units stacked in a periodic structure. Each unit is composed of two dielectric materials: silicon 21 and zinc sulfide 22. The thickness of silicon 21 is 885 nm, and the thickness of zinc sulfide 22 is 900 nm. It contains a total of 6 layers with thicknesses of 885 nm, 900 nm, 885 nm, 900 nm, 885 nm and 900 nm, respectively. The high-refractive-index material layer silicon 21 is connected to the substrate absorption layer 1, and the low-refractive-index material layer zinc sulfide 22 is connected to the phase change layer.

[0046] Phase change layer 3 is vanadium dioxide with a thickness of 200 nm.

[0047] The antireflective layer 4 is aluminum oxide with a thickness of 150 nm.

[0048] The spectral absorption / emissivity in daytime heating mode and nighttime heat preservation mode is as follows: Figure 5 As shown, during the day, when the temperature of the coating material is above its phase transition temperature, the absorptivity of the coating material in the 0.3–2.5 μm solar radiation band is 0.67, and the emissivity in the entire 5–20 μm infrared band is 0.17. At night, when the temperature of the coating material is below its phase transition temperature, the average emissivity of the coating material in the "atmospheric window" 8–14 μm band is 0.39, and the average emissivity in the 5–8 μm and 14–20 μm atmospheric radiation bands is 0.66.

[0049] Example 3

[0050] See Figure 1 and Figure 2 A coating material for all-day adaptive heating and heat preservation includes, from bottom to top, a base absorption layer 1, a composite layer 2, a phase change layer 3, and an anti-reflection layer 4.

[0051] The substrate absorber layer 1 is aluminum oxide with a thickness of 150 μm.

[0052] The composite layer is composed of four units stacked in a periodic structure. Each unit is composed of two dielectric materials: germanium 21 and zinc oxide 22. The thickness of germanium 21 is 700 nm, and the thickness of zinc oxide 22 is 1000 nm. It contains a total of eight layers with thicknesses of 700 nm, 1000 nm, 700 nm, 1000 nm, 700 nm, 1000 nm, 700 nm, and 1000 nm, respectively. The high-refractive-index material layer germanium 21 is connected to the substrate absorption layer 1, and the low-refractive-index material layer zinc oxide 22 is connected to the phase change layer.

[0053] Phase change layer 3 is vanadium dioxide with a thickness of 200 nm.

[0054] The antireflective layer 4 is aluminum oxide with a thickness of 100 nm.

[0055] The spectral absorption / emissivity in daytime heating mode and nighttime heat preservation mode is as follows: Figure 6As shown, during the day, when the temperature of the coating material is above its phase transition temperature, the absorptivity of the coating material in the 0.3–2.5 μm solar radiation band is 0.67, and the emissivity in the entire 5–20 μm infrared band is 0.17. At night, when the temperature of the coating material is below its phase transition temperature, the average emissivity of the coating material in the "atmospheric window" 8–14 μm band is 0.30, and the average emissivity in the 5–8 μm and 14–20 μm atmospheric radiation bands is 0.60.

[0056] Example 4

[0057] See Figure 1 and Figure 2 A coating material for all-day adaptive heating and heat preservation includes, from bottom to top, a base absorption layer 1, a composite layer 2, a phase change layer 3, and an anti-reflection layer 4.

[0058] The substrate absorber layer 1 is aluminum oxide with a thickness of 250 μm.

[0059] The composite layer is composed of four units stacked in a periodic structure. Each unit is composed of two dielectric materials: silicon 21 and titanium dioxide 22. The thickness of silicon 21 is 880 nm, and the thickness of titanium dioxide 22 is 1200 nm. It contains a total of eight layers with thicknesses of 880 nm, 1200 nm, 880 nm, 1200 nm, 880 nm, 1200 nm, 880 nm, and 1200 nm, respectively. The high-refractive-index material layer silicon 21 is connected to the substrate absorption layer 1, and the low-refractive-index material layer titanium dioxide 22 is connected to the phase change layer.

[0060] Phase change layer 3 is vanadium dioxide with a thickness of 200 nm.

[0061] The antireflective layer 4 is aluminum oxide with a thickness of 70 nm.

[0062] The spectral absorption / emissivity in daytime heating mode and nighttime heat preservation mode is as follows: Figure 7 As shown. During the day, when the temperature of the coating material is above its phase transition temperature, the absorptivity of the coating material in the 0.3–2.5 μm solar radiation band is 0.65, and the emissivity in the entire 5–20 μm infrared band is 0.17. At night, when the temperature of the coating material is below its phase transition temperature, the average emissivity of the coating material in the "atmospheric window" 8–14 μm band is 0.35, and the average emissivity in the 5–8 μm and 14–20 μm atmospheric radiation bands is 0.57.

[0063] Example 5

[0064] See Figure 1 and Figure 2 A coating material for all-day adaptive heating and heat preservation includes, from bottom to top, a base absorption layer 1, a composite layer 2, a phase change layer 3, and an anti-reflection layer 4.

[0065] The substrate absorber layer 1 is aluminum oxide with a thickness of 400 μm.

[0066] The composite layer is composed of 5 units stacked in a periodic structure. Each unit is composed of two dielectric materials: germanium 21 and magnesium fluoride 22. The thickness of germanium 21 is 700 nm, and the thickness of magnesium fluoride 22 is 2200 nm. It contains a total of 10 layers with thicknesses of 700 nm, 2200 nm, 700 nm, 2200 nm, 700 nm, 2200 nm, 700 nm, and 2200 nm, respectively. The high-refractive-index material layer germanium 21 is connected to the substrate absorption layer 1, and the low-refractive-index material layer magnesium fluoride 22 is connected to the phase change layer.

[0067] Phase change layer 3 is vanadium dioxide with a thickness of 200 nm.

[0068] The antireflective layer 4 is aluminum oxide with a thickness of 50 nm.

[0069] The spectral absorption / emissivity in daytime heating mode and nighttime heat preservation mode is as follows: Figure 8 As shown, during the day, when the temperature of the coating material is above its phase transition temperature, the absorptivity of the coating material in the 0.3–2.5 μm solar radiation band is 0.64, and the emissivity in the entire 5–20 μm infrared band is 0.17. At night, when the temperature of the coating material is below its phase transition temperature, the average emissivity of the coating material in the "atmospheric window" 8–14 μm band is 0.24, and the average emissivity in the 5–8 μm and 14–20 μm atmospheric radiation bands is 0.57.

[0070] Example 6

[0071] See Figure 1 and Figure 2 A coating material for all-day adaptive heating and heat preservation includes, from bottom to top, a base absorption layer 1, a composite layer 2, a phase change layer 3, and an anti-reflection layer 4.

[0072] The substrate absorber layer 1 is silicon dioxide with a thickness of 500 μm.

[0073] The composite layer is composed of four units stacked in a periodic structure. Each unit is composed of two dielectric materials: germanium 21 and magnesium fluoride 22. The thickness of germanium 21 is 700 nm, and the thickness of magnesium fluoride 22 is 2000 nm. It contains a total of eight layers with thicknesses of 700 nm, 2000 nm, 700 nm, 2000 nm, 700 nm, 2000 nm, 700 nm, and 2000 nm, respectively. The high-refractive-index material layer germanium 21 is connected to the substrate absorption layer 1, and the low-refractive-index material layer magnesium fluoride 22 is connected to the phase change layer.

[0074] Phase change layer 3 is vanadium dioxide with a thickness of 200 nm.

[0075] The antireflective layer 4 is aluminum oxide with a thickness of 90 nm.

[0076] The spectral absorption / emissivity in daytime heating mode and nighttime heat preservation mode is as follows: Figure 9 As shown, during the day, when the temperature of the coating material is above its phase transition temperature, the absorptivity of the coating material in the 0.3–2.5 μm solar radiation band is 0.66, and the emissivity in the entire 5–20 μm infrared band is 0.17. At night, when the temperature of the coating material is below its phase transition temperature, the average emissivity of the coating material in the "atmospheric window" 8–14 μm band is 0.19, and the average emissivity in the 5–8 μm and 14–20 μm atmospheric radiation bands is 0.56.

[0077] Those skilled in the art will readily understand that the above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A coating material integrating all-day adaptive heating and heat preservation, characterized in that: It includes, from bottom to top, a base absorption layer, a composite layer, a phase change layer, and an antireflection layer; The material of the substrate absorption layer is either alumina or silicon dioxide; The composite layer material is a photonic crystal film material, which is composed of two media materials with different refractive indices stacked alternately in a periodic structure; The two media materials with different refractive indices consist of a high refractive index material layer and a low refractive index material layer, forming a structural unit, which contains 3 to 5 sequentially connected units. The layer connected to the substrate absorption layer is a high refractive index material layer, and the layer connected to the phase change layer is a low refractive index material layer. The phase change layer material is a material with thermally induced phase change characteristics, which can change from a high transmittance state to a high reflectance state in the entire infrared band before and after the phase change. The antireflective layer material is a material with a refractive index of less than 2 at a wavelength of 0.5 μm; The coating temperature is higher than the phase transition temperature of vanadium dioxide. The coating material has an average absorptivity greater than 0.6 in the visible light band and an average emissivity less than 0.2 in the entire infrared band, thus achieving the heating mode. The coating temperature is lower than the phase transition temperature of vanadium dioxide. The average emissivity of the coating material is greater than 0.55 in the 5-8 μm and 14-20 μm atmospheric radiation bands, and less than 0.35 in the 8-14 μm atmospheric transparent band, thus achieving the heat preservation mode. The thickness of the substrate absorption layer is 100–500 μm; The composite layer has 6 to 10 layers and a total thickness of 3 μm to 15 μm; The phase change layer is made of vanadium dioxide and has a thickness of 200 nm. The antireflective layer is made of aluminum oxide and has a thickness of 50–150 nm.

2. The all-day adaptive heating and heat preservation integrated coating material according to claim 1, characterized in that: The composite layer can produce selective strong reflection characteristics, forming a distributed Bragg reflector in the 8-14 μm atmospheric transparent band, and is transparent in the remaining 5-8 μm and 14-20 μm atmospheric radiation bands.

3. The all-day adaptive heating and heat preservation integrated coating material according to claim 1, characterized in that: The high refractive index material and the low refractive index material are germanium and zinc sulfide, or silicon and zinc sulfide, or germanium and zinc oxide, or silicon and titanium dioxide, or germanium and magnesium fluoride, respectively.

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