A building coating material, its preparation method and application

Abstract

This application relates to the field of building materials technology, and more particularly to a building coating material, its preparation method, and its application. A building coating material is provided, comprising a filler with selective reflectivity, a photoluminescent material, a polymer emulsion, additives, and water. The addition of the selectively reflective filler results in a coating with high reflectivity only within its spectral response band, enhancing the intensity of incident solar radiation and improving the power conversion efficiency of BiPV. Combined with the photoluminescent material, the photoluminescent material re-emits photons of specific wavelengths absorbed by the selectively reflective filler within the visible range, generating a photovoltaic effect, improving energy conversion efficiency, and simultaneously achieving effective radiative cooling. Therefore, the obtained building coating material is suitable for a wider range of building types and surfaces, possessing significant market potential and practical usability.

Description

[0001] This application claims priority to Chinese Patent Application No. 202411996812.6, filed on December 31, 2024, with the Chinese Patent Office, entitled “A Building Coating Material and Its Preparation Method and Application”, and U.S. Provisional Application No. US 63 / 725,020, DAS Code 6609, filed on November 26, 2024, with the U.S. Patent and Trademark Office, entitled “Spectrally Engineered Coatings Integrated with Bifacial Solar Photovoltaics for Synergistic Power Generation and Radiative Cooling”, the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application belongs to the field of building materials technology, and in particular relates to a building coating material, its preparation method and application. Background Technology

[0003] In today's world, energy has become a global concern. With population growth and accelerated urbanization, land resources are becoming increasingly scarce, and the energy efficiency of confined spaces such as building rooftops is becoming increasingly prominent. How to achieve efficient energy use within limited spaces has become a crucial challenge we face.

[0004] The current state of energy efficiency in space-constrained environments is far from satisfactory. On the one hand, traditional building rooftops often serve merely as a covering layer, their energy utilization value not being fully realized. In many cities, vast amounts of rooftop space remain idle, wasting valuable solar energy resources. On the other hand, even when some buildings have installed solar panels and other energy equipment, poor design and aging equipment result in low energy conversion efficiency, failing to fully realize their potential. Furthermore, energy management in space-constrained environments also faces numerous problems, lacking effective monitoring and control measures, leading to severe energy waste.

[0005] Current technologies, such as traditional photovoltaic systems and radiative cooling solutions, are effective in isolation, but cannot be effectively combined due to material and structural limitations. Coatings currently used in photovoltaic systems often lack the ability to selectively reflect specific wavelengths of light, leading to increased heat and reduced power generation efficiency. Similarly, while radiative cooling technologies are effective at dissipating heat, they do not promote energy generation. Therefore, a solution is urgently needed to improve the performance of current buildings in generating electricity while simultaneously reducing heat buildup. Summary of the Invention

[0006] The purpose of this application is to provide a building coating material, its preparation method and application, which aims to solve the problem that buildings in the prior art cannot generate electricity while reducing heat accumulation.

[0007] To achieve the above-mentioned objectives, the technical solution adopted in this application is as follows: In a first aspect, this application provides a building coating material, comprising the following components by weight percentage, based on 100% of the total weight of the building coating material: Fillers with selective reflectivity account for 20% to 30%; Photoluminescent materials: 5%~20%; Polymer emulsion 10%~15%; Additives 5%~8%; Water content: 30%~50%.

[0008] In some embodiments, the filler having selective reflectivity is selected from at least one of titanium dioxide, silicon dioxide, magnesium oxide, and aluminum oxide.

[0009] In some embodiments, the photoluminescent material is selected from at least one of rare earth materials, quantum dot materials, and perovskite materials.

[0010] In some embodiments, the polymer emulsion is selected from at least one of styrene-propylene emulsion and polyurethane emulsion.

[0011] In some embodiments, the additive includes at least one of an aqueous wetting agent, a dispersant, and a film-forming agent.

[0012] In some embodiments, the aqueous wetting agent includes at least one of hydrocarbon chain wetting agents, alkynyl alcohol wetting agents, alkynyl alcohol-modified polyol wetting agents, and organosilicon wetting agents.

[0013] In some embodiments, the dispersant includes at least one of ionic dispersants, amphoteric dispersants, nonionic dispersants, electrically neutral dispersants, and polymeric dispersants.

[0014] In some embodiments, the film-forming agent includes at least one of alcohol-based film-forming agents, alcohol ester-based film-forming agents, alcohol ether-based film-forming agents, and alcohol ether ester-based film-forming agents.

[0015] Secondly, this application provides a method for preparing a building coating material, comprising the following steps: Based on the components of the above-mentioned building coating materials; A building coating material is obtained by mixing fillers with selective reflectivity, photoluminescent materials, polymer emulsions, additives, and water.

[0016] Thirdly, this application provides a method for cooling and improving the efficiency of a photovoltaic system, wherein a coating is applied to the ground or base where the photovoltaic panel or photovoltaic support is located, wherein the coating is prepared using the aforementioned building coating material.

[0017] In some embodiments, the thickness of the coating is 100 micrometers to 300 micrometers.

[0018] In some embodiments, the photovoltaic panel includes a single-sided photovoltaic panel or a double-sided photovoltaic panel.

[0019] The first aspect of this application provides a building coating material. This coating material uses a polymer emulsion as its base material to ensure its suitability for large-scale application on building surfaces. Furthermore, it includes a filler with selective reflectivity, a photoluminescent material, additives, and water. The addition of the selectively reflective filler ensures that the coating exhibits high reflectivity only within its spectral response band, enhancing the intensity of incident solar radiation and improving the power conversion efficiency of BiPV. The selective absorption of the coating minimizes energy loss outside the active response spectrum, reducing non-photovoltaic heat gain. Combined with the photoluminescent material, the photoluminescent material re-emits photons of specific wavelengths absorbed by the selectively reflective filler within the visible range, generating a photovoltaic effect and improving energy conversion efficiency while simultaneously achieving effective radiative cooling. Therefore, the resulting building coating material simultaneously achieves concentrated absorption of photons in a specific spectral response band and performs solar energy conversion and radiative cooling, making it suitable for a wider range of building types and surfaces, and possessing significant market potential and practical usability.

[0020] The second aspect of this application provides a method for preparing a building coating material. This method only requires mixing the components of the building coating material to obtain the building coating material. The preparation method is simple and easy to operate. It does not require the use of large-scale instruments and equipment. The building coating material can be obtained by simple mixing, which is conducive to industrial application.

[0021] The photovoltaic system cooling and efficiency enhancement method provided in the third aspect of this application involves applying the aforementioned building coating material to the ground or base where the photovoltaic panel or photovoltaic support is located. This coating optimizes the selective absorption of useful wavelengths of light by the solar cells and minimizes heat load. Furthermore, it better converts ultraviolet and near-infrared rays into visible light to improve power generation and achieve cooling. This facilitates a better balance between cooling and power generation, making the system more reliable and durable in high-temperature environments, reducing efficiency loss due to heat accumulation, and further improving the cooling performance and efficiency of the photovoltaic system, thus promoting its widespread use. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is the spectral diagram of the coating provided in Embodiment 1 of this application.

[0024] Figure 2 This is the SEM image provided in Embodiment 1 of this application.

[0025] Figure 3 These are physical images and photoluminescence images of the coating provided in Embodiment 1 of this application.

[0026] Figure 4 This is the emission spectrum of the coating provided in Embodiment 1 of this application under ultraviolet excitation light.

[0027] Figure 5 This is the emission spectrum of the coating provided in Embodiment 1 of this application under near-infrared excitation light. Detailed Implementation

[0028] To make the technical problems, technical solutions, and beneficial effects of this application clearer, the following detailed description is provided in conjunction with embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0029] In this application, the term "and / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0030] In this application, "at least one" means one or more, and "more than one" means two or more. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of single or multiple items. For example, "at least one of a, b, or c", or "at least one of a, b, and c", can both mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can be single or multiple.

[0031] It should be understood that in the various embodiments of this application, the order of the above processes does not imply the order of execution. Some or all steps may be executed in parallel or sequentially. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0032] The terminology used in the embodiments of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of this application. The singular forms "a" and "the" as used in the embodiments of this application and the appended claims are also intended to include the plural forms, unless the context clearly indicates otherwise.

[0033] The weights of the relevant components mentioned in the embodiments of this application can refer not only to the specific content of each component, but also to the proportional relationship between the weights of the components. Therefore, any scaling up or down of the content of the relevant components according to the embodiments of this application is within the scope disclosed in the embodiments of this application. Specifically, the mass in the embodiments of this application can be a well-known unit of mass in the chemical industry, such as µg, mg, g, or kg.

[0034] The terms "first" and "second" are used for descriptive purposes only, to distinguish objects, such as substances, from one another, and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. For example, without departing from the scope of the embodiments of this application, "first XX" may also be referred to as "second XX," and similarly, "second XX" may also be referred to as "first XX." Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of that feature.

[0035] The first aspect of this application provides a building coating material, which, based on 100% of the total weight of the building coating material, includes the following components by weight percentage: Fillers with selective reflectivity account for 20% to 30%; Photoluminescent materials: 5%~20%; Polymer emulsion 10%~15%; Additives 5%~8%; Water content: 30%~50%.

[0036] The first aspect of this application provides a building coating material. This coating material uses a polymer emulsion as its base material to ensure its suitability for large-scale application on building surfaces. Further, it includes a filler with selective reflectivity, a photoluminescent material, additives, and water. The addition of the selectively reflective filler ensures that the coating exhibits high reflectivity only within its spectral response band, enhancing the intensity of incident solar radiation and improving the power conversion efficiency of BiPV. The selective absorption of the coating minimizes energy loss outside the active response spectrum, reducing non-photovoltaic heat gain. Combined with the photoluminescent material, the photoluminescent material re-emits photons of specific wavelengths absorbed by the selectively reflective filler within the visible range, generating a photovoltaic effect and improving energy conversion efficiency while simultaneously achieving effective radiative cooling. Therefore, the resulting building coating material simultaneously achieves concentrated absorption of photons in a specific spectral response band and performs solar energy conversion and radiative cooling, making it suitable for a wider range of building types and surfaces, with significant market potential and practical usability.

[0037] The coating material, by weight (100%), includes 20%–30% selective reflective filler. This selective reflective filler exhibits high reflectivity within the target spectral response band, thereby enhancing the intensity of incident sunlight, preventing absorption of light in other bands, and improving power conversion efficiency. Excessive addition of selective reflective filler will affect the coating's cost, structure, and spectral performance; conversely, insufficient addition will also affect the coating's structure and spectral performance.

[0038] In some embodiments, the weight percentage of fillers with selective reflectivity, based on 100% of the total weight of the building coating material, includes, but is not limited to, typical but non-limiting values ​​such as 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, and 30%.

[0039] In some embodiments, the filler having selective reflectivity is selected from at least one of titanium dioxide, silicon dioxide, magnesium oxide, and aluminum oxide.

[0040] In some embodiments, the filler with selective reflectivity is selected from titanium dioxide, a white pigment with excellent optical properties due to its unique crystal structure and surface characteristics. The ion arrangement and surface state in its crystal structure enable titanium dioxide to effectively reflect infrared radiation and reduce heat absorption. In specific applications, the particle size of titanium dioxide is 200-450 nm.

[0041] In some embodiments, the filler with selective reflectivity is selected from silica. Silica exhibits excellent reflectivity for all wavelengths of light. Specifically, silica has a reflectivity of 70%–80% for short-wave ultraviolet light (200–280 nm), 80%–85% for medium-wave ultraviolet light (280–400 nm), over 85% for visible light (400–800 nm), and over 70% for near-infrared light in the 800–1350 nm wavelength range. In practical applications, nano-sized silica must be selected. If the silica particle size is too large, the particles will interfere with each other, resulting in lower reflectivity for all wavelengths of light.

[0042] In some embodiments, the filler with selective reflectivity is selected from magnesium oxide. Magnesium oxide has a certain reflectivity in the ultraviolet region, especially in the wavelength range of 200-300 nm, where the reflectivity is relatively high, generally around 30%-50%. In the visible light range, the reflectivity of magnesium oxide is usually between 80%-90%. In the wavelength range of 700-1500 nm, the reflectivity gradually decreases from around 70% to 40%. In practical applications, high-purity magnesium oxide with small particle size is selected. Generally, the purity is controlled above 90%, as too many impurities will reduce the reflectivity of magnesium oxide. The particle size is controlled at 10-50 nm. Smaller magnesium oxide particles have a larger specific surface area and increased surface energy, which is beneficial for enhancing reflectivity.

[0043] In some embodiments, the filler with selective reflectivity is selected from alumina, which has high reflectivity in the ultraviolet region, typically around 80% to 90% in the visible light range, and 40% to 70% in some near-infrared bands. Selecting high-purity alumina with smaller particle size results in superior optical performance and reflectivity.

[0044] The building coating material comprises 5% to 20% photoluminescent material by weight, based on a total weight percentage of 100%. This photoluminescent material can re-emit photons from absorbed sunlight within the visible range, thus generating a photovoltaic effect; it also provides a cooling effect. When used in conjunction with fillers possessing selective reflectivity, it can improve the overall building energy efficiency. Insufficient photoluminescent material by weight will reduce the photoluminescence quantum yield, while excessive addition will result in excessively high absorption rates.

[0045] In some embodiments, the weight percentage of photoluminescent material, based on the total weight of the building coating material as 100%, includes, but is not limited to, typical but non-limiting values ​​such as 5%, 7%, 9%, 10%, 12%, 15%, 17%, 19%, and 20%.

[0046] In some embodiments, the photoluminescent material is selected from at least one of rare earth materials, quantum dot materials, and perovskite materials.

[0047] In some embodiments, the photoluminescent material is selected from rare earth materials, specifically photoluminescent rare earth materials, including rare earth phosphors or long-afterglow photoluminescent materials. The rare earth phosphors include tri-color rare earth phosphors, composed of red, green, and blue phosphors; wherein the red phosphor includes, but is not limited to, Y₂O₃:Eu. 3+ Green powder includes, but is not limited to, LaPO4:Ce 3+ Blue powder includes, but is not limited to, BaMgAl 10 O 17 Eu 2+ Long-afterglow photoluminescent materials include, but are not limited to, aluminate series SrAl2O4:Eu 2+ SrAl2O4:Dy 3+ Rare earth activated sulfides of the silicate series.

[0048] In some embodiments, the photoluminescent material is selected from quantum dot materials, wherein quantum dot materials include, but are not limited to, at least one of carbon quantum dots, semiconductor quantum dots, and metal quantum dots.

[0049] In some embodiments, the photoluminescent material is selected from perovskite materials, wherein the perovskite materials include, but are not limited to, at least one of orthorhombic perovskite structure materials, cubic perovskite structure materials, and hexagonal crystalline non-perovskite structure materials. The building coating material comprises 10% to 15% polymer emulsion by weight, based on 100% of the total weight of the coating material. The provided building coating material uses a polymer emulsion as the base material to ensure that the prepared coating material is suitable for large-scale application on building surfaces. The coating is made using a water-based polymer emulsion method, making the process environmentally friendly and suitable for large-scale application.

[0050] In some embodiments, the weight percentage of the polymer emulsion, based on the total weight of the building coating material as 100%, includes, but is not limited to, typical but non-limiting values ​​such as 10%, 11%, 12%, 13%, 14%, and 15%.

[0051] In some embodiments, the polymer emulsion is selected from at least one of styrene-propylene emulsion and polyurethane emulsion.

[0052] The total weight of the building coating material is 100%, including additives at a weight percentage of 5% to 8%. Adding additives primarily improves the various properties of the coating material.

[0053] In some embodiments, the additive includes at least one of an aqueous wetting agent, a dispersant, and a film-forming agent.

[0054] In some embodiments, the aqueous wetting agent includes at least one of hydrocarbon chain wetting agents, alkynyl alcohol wetting agents, alkynyl alcohol-modified polyol wetting agents, and organosilicon wetting agents.

[0055] In some embodiments, the dispersant includes at least one of ionic dispersants, amphoteric dispersants, nonionic dispersants, electrically neutral dispersants, and polymeric dispersants.

[0056] In some embodiments, the film-forming agent includes at least one of alcohol-based film-forming agents, alcohol ester-based film-forming agents, alcohol ether-based film-forming agents, and alcohol ether ester-based film-forming agents.

[0057] A second aspect of this application provides a method for preparing a building coating material, comprising the following steps: S01. Based on the components of the above-mentioned building coating material; S02. A building coating material is obtained by mixing fillers with selective reflectivity, photoluminescent materials, polymer emulsions, additives and water.

[0058] The second aspect of this application provides a method for preparing a building coating material. This method only requires mixing the components of the building coating material to obtain the building coating material. The preparation method is simple and easy to operate. It does not require the use of large instruments and equipment. The building coating material can be obtained by simple mixing, which is conducive to industrial application.

[0059] In step S01, the components of the building coating material are as described above; the types and amounts of each component are as discussed above, and will not be repeated here to save space.

[0060] In step S02, fillers with selective reflectivity, photoluminescent materials, polymer emulsions, additives, and water are mixed to obtain building coating materials.

[0061] In some embodiments, the mixing process includes: The same amount of polymer emulsion and water, along with additives, are mixed in a first mixing process to obtain a first mixture; then the first mixture is mixed with reflective fillers and photoluminescent materials in a second mixing process to obtain a building coating material.

[0062] The third aspect of this application provides a method for cooling and improving the efficiency of a photovoltaic system, wherein a coating is applied to the ground or base where the photovoltaic panel or photovoltaic support is located, and the coating is prepared using the above-mentioned building coating material.

[0063] The photovoltaic system cooling and efficiency enhancement method provided in the third aspect of this application involves applying the aforementioned building coating material to the ground or base where the photovoltaic panel or photovoltaic support is located. This coating optimizes the selective absorption of useful wavelengths of light by the solar cells and minimizes heat load. Furthermore, it better converts ultraviolet and near-infrared rays into visible light to improve power generation and achieve cooling. This facilitates a better balance between cooling and power generation, making the system more reliable and durable in high-temperature environments, reducing efficiency loss due to heat accumulation, and further improving the cooling performance and efficiency of the photovoltaic system, thus enabling its widespread application.

[0064] The coating process can be completed using standard techniques such as spraying, rolling, or brushing.

[0065] In some embodiments, the thickness of the coating is 100 micrometers to 300 micrometers. In some specific embodiments, the thickness of the coating includes, but is not limited to, typical but non-limiting values ​​such as 100 micrometers, 120 micrometers, 150 micrometers, 170 micrometers, 200 micrometers, 220 micrometers, 250 micrometers, 270 micrometers, and 300 micrometers.

[0066] In some embodiments, the photovoltaic panel includes a single-sided photovoltaic panel or a double-sided photovoltaic panel.

[0067] The following description is based on specific embodiments.

[0068] Example 1 Building Coating Materials and Their Preparation Methods The coating material comprises the following components by weight percentage, based on a total weight of 100% of the building coating material: 20% of the filler has selective reflectivity; Photoluminescent materials 5%; Polymer emulsion 10%; Water-based wetting agent (organosilicon) 2%; Dispersant (polymer) 2%; Film-forming agent (alcohol ether ester) 1%; Water 60%; Among them, the filler with selective reflectivity is selected from titanium dioxide, the photoluminescent material is selected from rare earth materials (including yttrium, europium and terbium rare earth phosphors), and the polymer emulsion is selected from styrene-propylene emulsion.

[0069] The preparation method of architectural coating materials includes the following steps: Based on the components of the provided building coating material; A first mixture is obtained by mixing a polymer emulsion, an aqueous wetting agent, a dispersant, a film-forming agent, and water. This mixture is then mixed with a filler with selective reflectivity and a photoluminescent material to obtain a building coating material.

[0070] Example 2 Compared with Example 1, the "amount of filler with selective reflectivity" was changed to "25%", while all other contents remained the same.

[0071] Example 3 Compared with Example 1, the "amount of filler with selective reflectivity" was changed to "30%", while all other contents remained the same.

[0072] Example 4 Compared with Example 1, the "amount of photoluminescent material added" was changed to "10%", while all other contents remained the same.

[0073] Example 5 Compared with Example 1, the "amount of photoluminescent material added" was changed to "15%", while all other contents remained the same.

[0074] Example 6 Compared with Example 1, the "amount of photoluminescent material added" was changed to "20%", while all other contents remained the same.

[0075] Example 7 Compared with Example 1, the "amount of polymer emulsion added" was changed to "15%", while all other contents remained the same.

[0076] Example 8 Compared with Example 1, "the filler with selective reflectivity is selected from titanium dioxide" was changed to "the filler with selective reflectivity is selected from silicon dioxide", while all other contents remained the same.

[0077] Example 9 Compared with Example 1, "the filler with selective reflectivity is selected from titanium dioxide" was changed to "the filler with selective reflectivity is selected from magnesium oxide", while all other contents remained the same.

[0078] Example 10 Compared with Example 1, "the filler with selective reflectivity is selected from titanium dioxide" was changed to "the filler with selective reflectivity is selected from alumina", while all other contents remained the same.

[0079] Example 11 Compared with Example 1, "the photoluminescent material is selected from rare earth materials (including yttrium, europium and terbium rare earth phosphors)" was changed to "the photoluminescent material is selected from quantum dot materials carbon quantum dots", and all other contents are the same.

[0080] Example 12 Compared to Example 1, the phrase "the photoluminescent material is selected from rare earth materials (including yttrium, europium, and terbium rare earth phosphors)" has been modified to "the photoluminescent material is selected from perovskite material CsPbBrxI3". "x", all other content is the same.

[0081] Example 13 Compared with Example 1, "polymer emulsion selected from styrene-propylene emulsion" was changed to "polymer emulsion selected from polyurethane emulsion", while all other contents remained the same.

[0082] Property Testing and Result Analysis The building coating obtained in Example 1 was subjected to spectral analysis using a spectrometer, and the resulting spectrum is shown below. Figure 1 As shown, it can be seen that Figure 1 The spectrum shows that the coating has a high solar reflectivity of up to 95% across the entire solar radiation band, while also having a thermal emissivity of up to 0.95 in the 4-30 micrometer range.

[0083] Further electron microscopy analysis was performed, and the resulting SEM images are shown below. Figure 2 As shown in the SEM image, the coating is based on a polymer emulsion framework and doped with different functionalized fillers to optimize the spectral properties of the coating.

[0084] Provide a physical image and a photoluminescence diagram of the coating. For example... Figure 3 It can be seen that the photoluminescence properties of this coating have two characteristics: 1. It can be excited by ultraviolet light to emit visible light, and 2. It can also be excited by near-infrared light to emit visible light.

[0085] The coating prepared in Example 1 was analyzed under ultraviolet light excitation conditions and near-infrared light excitation conditions, such as... Figure 4 As shown, the emission spectrum of the coating under ultraviolet light excitation reveals the specific wavelengths of light re-emitted by the coating, demonstrating its efficiency in converting absorbed ultraviolet photons into visible light. Figure 5 As shown, the emission spectrum of the coating under near-infrared light excitation highlights the coating's ability to absorb near-infrared radiation and convert it into visible light, further improving the energy conversion efficiency of the bifacial photovoltaic cell.

[0086] In summary, the building coating material provided in this application uses a polymer emulsion as its base material to ensure that the prepared coating material is suitable for large-scale application on building surfaces. Furthermore, it includes a filler with selective reflectivity, a photoluminescent material, additives, and water. The addition of the selectively reflective filler ensures that the resulting coating exhibits high reflectivity only within its spectral response band, enhancing the intensity of incident solar radiation and improving the power conversion efficiency of BiPV. The selective absorption of the coating minimizes energy loss outside the active response spectrum, reducing non-photovoltaic heat gain. Combined with the use of the photoluminescent material, the photoluminescent material re-emits photons of specific wavelengths absorbed by the selectively reflective filler within the visible range, generating a photovoltaic effect, improving energy conversion efficiency, and simultaneously achieving effective radiative cooling. Therefore, the resulting building coating material simultaneously achieves concentrated absorption of photons in a specific spectral response band and performs solar energy conversion and radiative cooling, making it suitable for a wider range of building types and surfaces, with significant market potential and practical usability.

[0087] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A building coating material, characterized in that, The building coating material comprises the following components by weight percentage, based on a total weight of 100%: Fillers with selective reflectivity account for 20% to 30%; Photoluminescent materials: 5%~20%; Polymer emulsion 10%~15%; Additives 5%~8%; Add water until the total weight is 100%.

2. The building coating material according to claim 1, characterized in that, The filler with selective reflectivity is selected from at least one of titanium dioxide, silicon dioxide, magnesium oxide, and aluminum oxide.

3. The building coating material according to claim 1, characterized in that, The photoluminescent material is selected from at least one of rare earth materials, quantum dot materials, and perovskite materials.

4. The building coating material according to claim 1, characterized in that, The polymer emulsion is selected from at least one of styrene-propylene emulsion and polyurethane emulsion.

5. The building coating material according to claim 1, characterized in that, The additives include at least one of aqueous wetting agents, dispersants, and film-forming agents.

6. The building coating material according to claim 5, characterized in that, The aqueous wetting agent includes at least one of hydrocarbon chain wetting agents, alkynol wetting agents, alkynol-modified polyol wetting agents, and organosilicon wetting agents; and / or, The dispersant includes at least one of ionic dispersants, amphoteric dispersants, nonionic dispersants, electrically neutral dispersants, and polymeric dispersants; and / or, The film-forming agent includes at least one of alcohol-based film-forming agents, alcohol ester-based film-forming agents, alcohol ether-based film-forming agents, and alcohol ether ester-based film-forming agents.

7. A method for preparing a building coating material, characterized in that, Includes the following steps: Each component of the building coating material according to any one of claims 1 to 6; A building coating material is obtained by mixing fillers with selective reflectivity, photoluminescent materials, polymer emulsions, additives, and water.

8. A method for cooling and improving the efficiency of a photovoltaic system, characterized in that, A coating is applied to the ground or base where the photovoltaic panel or photovoltaic bracket is located, wherein the coating is prepared using the building coating material described in any one of claims 1 to 6.

9. The method for cooling and improving the efficiency of a photovoltaic system according to claim 8, characterized in that, The coating has a thickness of 100 micrometers to 300 micrometers.

10. The method for cooling and improving the efficiency of a photovoltaic system according to claim 8, characterized in that, The photovoltaic panel includes a single-sided photovoltaic panel or a double-sided photovoltaic panel.

Images