Solar light and heat glass and method for manufacturing the same

Abstract

The application provides solar light and heat glass and a preparation method thereof, and belongs to the technical field of light and heat glass, and comprises the following steps: S1, preparing a PVB-based light and heat phase change intermediate film; S2, preparing a laminated glass; S3, coating a Cs x The WO3 coating liquid is poured on the outer surface of the laminated glass, is scraped to form a film, is dried by heating, and forms a Cs x WO3 coating on the outer surface, and the solar light and heat glass is prepared. The application can improve the solar light and heat conversion efficiency while maintaining good light transmittance.

Description

Technical Field

[0001] This invention relates to the field of solar thermal glass technology, specifically to a solar thermal glass and its preparation method. Background Technology

[0002] Solar thermal glass, as a special functional glass material, has the ability to convert some solar radiation into heat energy, and has promising applications in solar energy utilization, building energy conservation, winter heating, and special energy-saving building envelopes. With the increasing demands for energy conservation and comfort in high-performance buildings, solar thermal glass, which can both allow for natural lighting and effectively regulate solar energy, is gradually becoming a research focus. Currently, solar thermal glass is used in high-performance building exterior windows, glass curtain walls, skylights, sunrooms, and some special building components that require transparent enclosures while also meeting energy-saving requirements.

[0003] Existing solar thermal glass typically improves the glass's solar energy absorption rate by introducing photothermal conversion materials into the glass system, thereby increasing the temperature of the glass surface or its interior and reducing the energy consumption of traditional heating or thermal equipment. Photothermal conversion materials can be made into thin films and coated on the glass surface, or incorporated into the glass body during the glass melting process. Several common engineering approaches exist: First, metal films, metal oxide films, or low-emissivity films are deposited on the surface of float glass or tempered glass using methods such as physical vapor deposition (PVD) and chemical vapor deposition (CVD). Second, wet processes such as sol-gel, spraying, and roller coating are used to uniformly coat the glass surface with inorganic or organic-inorganic composite coatings containing photothermal conversion particles. Third, specific metal oxides, infrared absorbers, or nanoparticles are added during the glass melting process to give the glass body a specific solar transmittance / absorption spectrum, thereby improving the glass's solar energy absorption rate.

[0004] However, existing technologies for preparing solar thermal glass using photothermal conversion materials still have several unresolved problems. On the one hand, when photothermal conversion materials are incorporated into the glass matrix, they need to undergo high-temperature melting and forming processes. Uneven dispersion of some functional particles can easily lead to agglomeration, introducing new bubbles and stress defects, affecting the mechanical strength of the glass and causing a decrease in light transmittance. On the other hand, when photothermal conversion materials exist on the glass surface as a coating, they need to withstand multiple effects such as sunlight exposure, rapid temperature changes, and rain erosion, which can easily lead to coating aging or failure of the photothermal conversion materials.

[0005] Therefore, there is a need to provide a solar thermal glass and its preparation method to solve the problems existing in the prior art. Summary of the Invention

[0006] In view of this, the present invention provides a solar thermal glass and its preparation method, which can improve the solar thermal conversion efficiency while maintaining good light transmittance.

[0007] To achieve the above objectives, the present invention provides a method for preparing solar thermal glass, comprising the following steps:

[0008] S1. PVB resin powder, ZnO / h-BN@PDA composite powder and additives are dry mixed and fed into a twin-screw extruder. After melting and mixing at 140~160℃, the temperature is adjusted to 100~120℃, paraffin microcapsules are added, and melting and mixing are continued. The mixture is then extruded, calendered into sheets, cooled and solidified to obtain a PVB-based photothermal phase change intermediate film.

[0009] S2. Lay the interlayer film flat on the surface of a pretreated glass substrate, then cover the interlayer film with a second pretreated glass substrate. After vacuum heating and pre-pressing, place it in an autoclave, heat it up, press it under high pressure, let it cool naturally to room temperature, and then trim and polish it to obtain laminated glass.

[0010] S3, Cs x WO3 coating solution is poured onto the outer surface of laminated glass, coated into a film, heated and dried to form Cs on the outer surface. x WO3 coating is used to produce solar thermal glass.

[0011] This invention introduces a PVB-based photothermal phase change interlayer into the solar thermal glass. The ZnO in the ZnO / h-BN@PDA composite powder exhibits strong absorption of ultraviolet light, releasing the absorbed energy as heat. Polydopamine (PDA), with its conjugated aromatic structure, also absorbs visible light, converting some light energy into heat. This results in numerous dispersed "heating points" within the interlayer, effectively converting ultraviolet and some visible light from sunlight onto the glass into heat, thus improving the overall photothermal conversion efficiency and increasing the utilization rate of solar thermal energy. Furthermore, hexagonal boron nitride (h-BN) has a high thermal conductivity, forming a thermal pathway within the PVB matrix. This facilitates faster transfer of locally generated heat to the surrounding paraffin microcapsules, thereby improving the overall thermal conductivity and heating response speed of the phase change layer. In addition, the hydroxyl and amino groups on the PDA shell can interact with the hydroxyl and acetal groups in PVB, improving the dispersion and interfacial bonding of inorganic particles in PVB, thereby avoiding the problem of uneven dispersion and agglomeration of inorganic particles leading to the introduction of air bubbles that have an adverse effect on light transmittance.

[0012] This invention utilizes paraffin microcapsules as a phase change material to prepare a PVB-based photothermal phase change interlayer, enabling it to exhibit significant absorption and release of latent heat of phase change within a temperature range close to to slightly above room temperature. When ambient temperature or solar irradiance increases, the paraffin core melts from a solid to a liquid state, absorbing a large amount of latent heat and effectively "storing" the heat. When the temperature decreases, the paraffin recrystallizes, slowly releasing the stored heat. This thermal buffering behavior helps reduce the thermal stress of the glass-interlayer system, improving the lifespan of solar thermal glass under diurnal or seasonal temperature variations. Under appropriate building design conditions, this also contributes to improved indoor thermal comfort and building energy efficiency.

[0013] This invention involves coating the outer surface of glass with Cs. x The WO3 photothermal coating absorbs near-infrared light, and ZnO / h-BN@PDA in the intermediate film is responsible for the absorption and heat conduction of ultraviolet and some visible light. The entire glass structure enables the effective utilization of sunlight from ultraviolet, visible to near-infrared, and can convert more solar radiation falling on the glass into usable heat.

[0014] Optionally, the ZnO / h-BN@PDA composite powder is prepared by mixing 500-800 parts by volume of deionized water and 1.5-2 parts by mass of dopamine hydrochloride, slowly adjusting the pH of the solution to 8.0-8.7 with NaHCO3, slowly adding ZnO / h-BN dispersion and magnetically stirring for 10-12 hours, centrifuging at 6000-8000 rpm for 10-20 minutes, removing the supernatant, washing the precipitate with deionized water and anhydrous ethanol 2-3 times sequentially, vacuum drying at 70-80℃ for 12-16 hours, grinding, and sieving.

[0015] The ZnO / h-BN@PDA composite powder of the present invention is obtained by the self-polymerization of dopamine under weakly alkaline conditions, which uniformly coats the surface of zinc oxide and hexagonal boron nitride particles to form a thin organic shell.

[0016] Preferably, the mesh size of the sieve used for sieving is 200 mesh.

[0017] The present invention preferably uses a 200-mesh sieve to sieve the dried ZnO / h-BN@PDA composite powder, which helps to remove obvious large particles and agglomerates, making the particle size distribution of the obtained powder more uniform, ensuring its dispersibility and stability in the PVB interlayer film system, and avoiding local stress concentration and increased scattering points that affect optical transparency and mechanical properties.

[0018] Optionally, the ZnO / h-BN dispersion is obtained by adding 0.8-1.2 parts by weight of nano zinc oxide powder and 0.4-0.7 parts by weight of hexagonal boron nitride nano powder to 450-550 parts by volume of 50% ethanol aqueous solution and ultrasonically dispersing for 30-40 minutes.

[0019] Optionally, in step S1, 180-230 parts by weight of PVB resin powder, 0.8-1.5 parts by weight of ZnO / h-BN@PDA composite powder, and additives are dry-mixed at 800-1000 rpm for 10-15 minutes at room temperature, then fed into a twin-screw extruder and melt-mixed at 140-160°C for 3-5 minutes. Subsequently, the barrel temperature is adjusted to 100-120°C in the rear section of the twin-screw extruder, and 40-55 parts by weight of paraffin microcapsules are added and melt-mixed for another 2-3 minutes. The mixture is then extruded, calendered into sheets, cooled, and cured to obtain a PVB-based photothermal phase change intermediate film. The additives are 35-60 parts by weight of trioctyl trimellitate, 0.4-0.6 parts by weight of UV absorber, and 0.3-0.5 parts by weight of hindered amine light stabilizer.

[0020] Preferably, the UV absorber has CAS number 1843-05-6 and the hindered amine light stabilizer has CAS number 82919-37-7.

[0021] Preferably, the core material of the paraffin microcapsule has a melting point of 25°C or 30°C, and the shell material is polymethyl methacrylate.

[0022] This invention selects a core material with a melting point of 25~30℃ to achieve melting and heat absorption when exposed to sunlight or slightly increased ambient temperature, and exothermic crystallization when the temperature drops, thus playing a certain temperature buffering role; the shell material uses polymethyl methacrylate with a refractive index similar to that of the PVB matrix to reduce the difference in refractive index at the interface, reduce light scattering, and thus maintain the transparency of the intermediate film, avoiding subsequent impact on the overall light transmittance.

[0023] Preferably, the thickness of the PVB-based photothermal phase change intermediate film is 0.75~0.8 mm.

[0024] The present invention controls the thickness of the PVB-based photothermal phase change interlayer to 0.75~0.8mm. At this thickness, the phase change heat storage capacity and photothermal conversion efficiency can be guaranteed while avoiding a significant decrease in light transmittance due to excessively thick interlayer.

[0025] Optionally, the pretreated glass substrate is obtained by ultrasonically cleaning low-iron float glass in propanol, anhydrous ethanol and deionized water for 10-15 minutes, and drying it at 55-65°C for 30-40 minutes.

[0026] Optionally, in step S2, a pre-treated glass substrate is laid flat on a stainless steel table covered with a silicone pad. An interlayer film is laid flat on the surface of the glass substrate, and then a second pre-treated glass substrate is placed on top of the interlayer film. After the two glass substrates are fully bonded together through the interlayer film, they are sent into a vacuum pre-pressing device and kept at a vacuum degree of -0.08 to -0.06 MPa and a temperature of 60 to 80°C for 10 to 20 minutes. After that, a pre-composite blank is obtained by rolling and pressing. The blank is then placed in an autoclave and heated to 130 to 140°C. It is then kept at a pressure of 0.8 to 1.2 MPa for 30 to 60 minutes. After that, the temperature is slowly lowered to 50°C and then allowed to cool naturally to room temperature. The blank is then trimmed and polished to obtain laminated glass.

[0027] Preferably, the PVB-based photothermal phase change intermediate film is cut to an edge size smaller than the edge size of the pretreated glass substrate, typically 2-3 mm.

[0028] The present invention controls the edge size of the PVB-based photothermal phase change intermediate film to be slightly smaller than the glass edge, which helps to prevent the intermediate film from being squeezed out of the glass edge during the pre-pressing and autoclave bonding process, and reduces wrinkling, curling and overflow.

[0029] Optionally, the Cs x The WO3 coating solution is prepared by adding 25-30 parts by weight of polyvinyl alcohol to 240-260 parts by volume of deionized water, and magnetically stirring at 70-80°C for 1.5-3 hours. Cs is then added. x The WO3 dispersion was further magnetically stirred for 60-80 minutes to obtain the Cs. x The WO3 dispersion was obtained by adding 6.2-6.7 parts by weight of cesium tungsten bronze powder and 0.25-0.35 parts by weight of polyvinylpyrrolidone to 240-260 parts by volume of deionized water and ultrasonically dispersing for 100-120 minutes.

[0030] The cesium tungsten bronze powder used in this invention can effectively absorb and utilize near-infrared solar energy, further improving the photothermal conversion efficiency of solar thermal glass.

[0031] Optionally, in step S3, the heating and drying time is 30-60 minutes and the temperature is 60-80°C; Cs is formed on the outer surface during high-temperature drying. x After the WO3 coating, an HF-SiO2 suspension was used to spray the outer surface, uniformly spraying the HF-SiO2 suspension onto the Cs. x The WO3 coating surface is dried at 120~130℃ for 60~80min to form an HF-SiO2 outer layer, and finally solar thermal glass is obtained.

[0032] This invention further applies an HF-SiO2 outer layer, endowing the solar thermal glass surface with excellent superhydrophobic and self-cleaning properties. Rainwater or water droplets can carry surface dust and dirt off naturally, maintaining the cleanliness of the glass surface and the optical performance of the coating for a long time. Simultaneously, it also protects against Cs... x The WO3 coating provides protection against water and stains and slows down aging.

[0033] Preferably, the Cs x The WO3 coating thickness is 3~5μm, and the HF-SiO2 outer layer thickness is 0.2~0.5μm.

[0034] Optionally, the HF-SiO2 suspension is obtained by adding 2.8-3.2 parts by mass of fumed silica to 400-500 parts by volume of anhydrous ethanol, stirring magnetically for 20-30 min, then ultrasonically dispersing for 20-30 min, and then adding 0.3-0.4 parts by volume of 0.01 mol / L ammonia water and 0.8-1.2 parts by volume of 1H,1H,2H,2H-perfluorodecyltrimethoxysilane dropwise while stirring for 6-8 h and ultrasonicating for 20-40 min.

[0035] The outer layer of the HF-SiO2 of this invention is composed of fluorosilane-modified fumed silica. Under ammonia catalysis and heating conditions, the fluorosilane water decomposes and merges with the SiO2 surface and the underlying Cs layer. x The hydroxyl groups on the surface of the WO3 coating undergo a condensation reaction to form a relatively strong silicon-oxygen network; the exposed perfluoroalkyl chains of HF-SiO2 significantly reduce the surface energy of the coating surface, thereby further endowing the outer surface of the solar thermal glass with hydrophobic and self-cleaning properties, while also providing a certain degree of barrier and protection against water vapor and pollutants.

[0036] Preferably, the fumed silica has CAS number 68909-20-6 and a particle size of 7 nm.

[0037] The present invention preferably uses fumed silica with a particle size of 7 nm, which is beneficial to maintaining the good transparency and low haze of solar thermal glass.

[0038] The present invention also provides a solar thermal glass, which is prepared by the above-described method for preparing solar thermal glass.

[0039] The above-described technical solution of the present invention has at least the following beneficial effects:

[0040] 1. This invention introduces ZnO / h-BN@PDA composite powder into the PVB-based photothermal phase change interlayer of solar thermal glass. ZnO primarily absorbs ultraviolet light, while PDA also absorbs some visible light, allowing the incident ultraviolet and some visible light to be converted into heat in a timely manner, forming dispersed photothermal "heating points" within the interlayer, thus improving photothermal conversion efficiency and solar energy utilization efficiency. h-BN has a high thermal conductivity, enabling the construction of thermal conduction pathways within the PVB matrix, allowing locally generated heat to be transferred more quickly to the surrounding paraffin microcapsules, improving the thermal conductivity and heating response speed of the phase change layer. Combined with Cs on the outer surface of the glass... x The selective absorption of near-infrared radiation by the WO3 photothermal coating enables the solar thermal glass of this invention to synergistically utilize solar energy across ultraviolet, visible, and near-infrared bands, converting more solar radiation falling on the glass into usable heat. Furthermore, the hydroxyl and amino groups on the PDA shell can interact with the hydroxyl and acetal groups in PVB, improving the dispersion and interfacial bonding of inorganic particles in the PVB matrix, reducing particle aggregation and bubble formation, and avoiding adverse effects on light transmittance.

[0041] 2. This invention uses paraffin microcapsules as a phase change material to prepare a PVB-based photothermal phase change interlayer film, which enables the interlayer film to have significant latent heat absorption and release functions in the temperature range close to room temperature to slightly above room temperature: when the ambient temperature or solar irradiance increases, the paraffin core material melts and absorbs heat to temporarily store heat; when the temperature decreases, the paraffin crystallizes and releases heat, realizing the slow release of heat, reducing the thermal stress of the glass-interlayer film system, and improving the service life of solar thermal glass under diurnal temperature difference and seasonal temperature difference conditions. Attached Figure Description

[0042] Figure 1 The sample temperatures (T) of Example 1 and Comparative Example 2 of this invention are as follows: t (The curve shows how the curve changes over time.) Detailed Implementation

[0043] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. The described embodiments are some embodiments of the present invention, and all other embodiments obtained by those skilled in the art based on the described embodiments of the present invention are within the scope of protection of the present invention.

[0044] Example 1

[0045] 1.2 g of nano zinc oxide powder and 0.7 g of hexagonal boron nitride nano powder (h-BN) were added to 550 mL of 50% (v / v) ethanol aqueous solution and ultrasonically dispersed for 40 min to obtain ZnO / h-BN dispersion. 800 mL of deionized water and 2 g of dopamine hydrochloride were mixed evenly, and the pH of the solution was slowly adjusted to 8.7 using NaHCO3. The ZnO / h-BN dispersion was slowly added and magnetically stirred for 12 h. After centrifugation at 8000 rpm for 20 min, the supernatant was removed, and the precipitate was washed three times successively with deionized water and anhydrous ethanol. The precipitate was vacuum dried at 80 °C for 12 h, ground, and sieved (using a 200-mesh sieve) to obtain ZnO / h-BN@PDA composite powder.

[0046] 210g of PVB resin powder was placed in a high-speed mixer, and 50g of trioctyl trimellitate, 1.5g of ZnO / h-BN@PDA composite powder, 0.55g of UV absorber (CAS No.: 1843-05-6), and 0.45g of hindered amine light stabilizer (CAS No.: 82919-37-7) were added sequentially. The mixture was dry-mixed at 1000rpm for 15min at room temperature, and then fed into a twin-screw extruder. The mixture was melt-mixed at 150℃ for 4min. Subsequently, the barrel temperature was adjusted to 100℃ in the rear section of the twin-screw extruder, and 55g of paraffin microcapsules (the core material was paraffin with a melting point of 25℃, and the shell material was polymethyl methacrylate, purchased from Hubei Saimo New Energy Technology Co., Ltd.) were added. The mixture was melt-mixed for another 2min, extruded, calendered into sheets, and cooled and cured to obtain a PVB-based photothermal phase change intermediate film (thickness of 0.8mm).

[0047] Low-iron float glass was used as the substrate and was ultrasonically cleaned in propanol, anhydrous ethanol, and deionized water for 15 minutes in sequence. It was then dried at 60°C for 40 minutes to obtain a pretreated glass substrate. The obtained PVB-based photothermal phase change interlayer was cut into pieces with an edge size 2 mm smaller than the edge size of the pretreated glass substrate. One piece of pretreated glass substrate was placed flat on a stainless steel table covered with a silicone pad. The interlayer was then laid flat on the surface of the glass, and a second piece of pretreated glass substrate was placed on top of the interlayer. After the two pieces of glass were completely bonded together through the interlayer, they were sent into a vacuum pre-pressing device and held at a vacuum degree of -0.08 MPa and 70°C for 20 minutes. After that, the pre-composite blank was rolled and placed in an autoclave. The blank was heated to 130°C and held at 1.0 MPa for 60 minutes. After that, the blank was slowly cooled to 50°C and then allowed to cool naturally to room temperature. The blank was then trimmed and polished to obtain laminated glass.

[0048] 3g of hydrophobic fumed silica (particle size 7nm, CAS No.: 68909-20-6) was added to 400mL of anhydrous ethanol, magnetically stirred for 30min, and then ultrasonically dispersed for 30min. Under continuous stirring, 0.38mL of 0.01mol / L ammonia and 1.2mL of 1H,1H,2H,2H-perfluorodecyltrimethoxysilane (CAS No.: 83048-65-1) were added dropwise, and the mixture was stirred for 8h and ultrasonically dispersed for 40min to obtain an HF-SiO2 suspension. 6.22g of cesium tungsten bronze powder (Cs) was added... x WO3 (CAS No.: 189619-69-0) and 0.26 g of polyvinylpyrrolidone were added to 250 mL of deionized water and ultrasonically dispersed for 120 min to obtain Cs. x WO3 dispersion; 28g polyvinyl alcohol was added to 250mL deionized water and magnetically stirred at 75℃ for 3h, then Cs was added. x The WO3 dispersion was further stirred magnetically for 80 minutes to obtain Cs. x WO3 coating solution; the above Cs x WO3 coating solution is poured onto the outer surface of laminated glass, coated into a film, and dried at 80°C for 50 minutes to form Cs on the outer surface. x WO3 coating (Cs) x The WO3 coating (4 μm thick) was fixed on the spraying platform, and the HF-SiO2 suspension was uniformly sprayed onto the Cs. x The WO3 coating surface is dried at 125℃ for 80 min to form an HF-SiO2 outer layer (HF-SiO2 outer layer thickness is 0.3μm), thus producing solar thermal glass.

[0049] Example 2

[0050] 0.8 g of nano zinc oxide powder and 0.4 g of hexagonal boron nitride nano powder were added to 450 mL of 50% (v / v) ethanol aqueous solution and ultrasonically dispersed for 30 min to obtain ZnO / h-BN dispersion. 500 mL of deionized water and 1.5 g of dopamine hydrochloride were mixed evenly, and the pH of the solution was slowly adjusted to 8.0 using NaHCO3. The ZnO / h-BN dispersion was slowly added and magnetically stirred for 10 h. After centrifugation at 6000 rpm for 10 min, the supernatant was removed, and the precipitate was washed twice with deionized water and anhydrous ethanol, respectively. The precipitate was vacuum dried at 70 °C for 12 h, ground, and sieved (using a 200-mesh sieve) to obtain ZnO / h-BN@PDA composite powder.

[0051] 180g of PVB resin powder was placed in a high-speed mixer, and 35g of trioctyl trimellitate, 0.8g of ZnO / h-BN@PDA composite powder, 0.4g of UV absorber (CAS No.: 1843-05-6), and 0.3g of hindered amine light stabilizer (CAS No.: 82919-37-7) were added sequentially. The mixture was dry-mixed at 800 rpm for 10 min at room temperature, and then fed into a twin-screw extruder. The mixture was melt-mixed at 140℃ for 3 min. Subsequently, the barrel temperature was adjusted to 100℃ in the rear section of the twin-screw extruder, and 40g of paraffin microcapsules (the core material was paraffin with a melting point of 30℃, and the shell material was polymethyl methacrylate, purchased from Hubei Saimo New Energy Technology Co., Ltd.) were added. The mixture was melt-mixed for another 3 min, extruded, calendered into sheets, and cooled and cured to obtain a PVB-based photothermal phase change intermediate film (thickness of 0.75mm).

[0052] Low-iron float glass was used as the substrate and was ultrasonically cleaned in propanol, anhydrous ethanol, and deionized water for 10 minutes in sequence. It was then dried at 55°C for 30 minutes to obtain a pretreated glass substrate. The obtained PVB-based photothermal phase change interlayer was cut into pieces with an edge size 3 mm smaller than the edge size of the pretreated glass substrate. One piece of pretreated glass substrate was placed flat on a stainless steel table covered with a silicone pad. The interlayer was then laid flat on the surface of the glass, and a second piece of pretreated glass substrate was placed on top of the interlayer. After the two pieces of glass were completely bonded together through the interlayer, they were sent into a vacuum pre-pressing device and held at a vacuum degree of -0.06 MPa and 60°C for 10 minutes. After that, the pre-composite blank was rolled and placed in an autoclave. The blank was heated to 130°C and held at 0.8 MPa for 30 minutes. After that, the blank was slowly cooled to 50°C and then allowed to cool naturally to room temperature. The blank was then trimmed and polished to obtain laminated glass.

[0053] 2.8 g of hydrophobic fumed silica (particle size 7 nm, CAS No.: 68909-20-6) was added to 400 mL of anhydrous ethanol, magnetically stirred for 20 min, and then ultrasonically dispersed for 20 min. Under continuous stirring, 0.3 mL of 0.01 mol / L ammonia water and 0.8 mL of 1H,1H,2H,2H-perfluorodecyltrimethoxysilane (CAS No.: 83048-65-1) were added dropwise, and the mixture was stirred for 6 h and ultrasonicated for 20 min to obtain an HF-SiO2 suspension. 6.2 g of cesium tungsten bronze powder (Cs) was added... x WO3 (CAS No.: 189619-69-0) and 0.25 g of polyvinylpyrrolidone were added to 240 mL of deionized water and ultrasonically dispersed for 100 min to obtain Cs. x WO3 dispersion: Add 25g polyvinyl alcohol to 240mL deionized water, stir magnetically at 70℃ for 1.5h, then add Cs. x The WO3 dispersion was further magnetically stirred for 60 minutes to obtain Cs.x WO3 coating solution; the above Cs x WO3 coating solution is poured onto the outer surface of laminated glass, coated into a film, and dried at 60°C for 30 minutes to form Cs on the outer surface. x WO3 coating (Cs) x The WO3 coating (3 μm thick) was fixed on the spraying platform, and the HF-SiO2 suspension was uniformly sprayed onto the Cs. x The WO3 coating surface is dried at 120℃ for 60 min to form an HF-SiO2 outer layer (HF-SiO2 outer layer thickness is 0.2μm), thus producing solar thermal glass.

[0054] Example 3

[0055] 1.2 g of nano zinc oxide powder and 0.5 g of hexagonal boron nitride nano powder were added to 500 mL of 50% (v / v) ethanol aqueous solution and ultrasonically dispersed for 35 min to obtain ZnO / h-BN dispersion. 600 mL of deionized water and 1.8 g of dopamine hydrochloride were mixed evenly, and the pH of the solution was slowly adjusted to 8.7 using NaHCO3. The ZnO / h-BN dispersion was slowly added and magnetically stirred for 11 h. After centrifugation at 8000 rpm for 15 min, the supernatant was removed, and the precipitate was washed three times successively with deionized water and anhydrous ethanol. The precipitate was vacuum dried at 78 °C for 15 h, ground, and sieved (using a 200-mesh sieve) to obtain ZnO / h-BN@PDA composite powder.

[0056] 230g of PVB resin powder was placed in a high-speed mixer, and 60g of trioctyl trimellitate, 1.5g of ZnO / h-BN@PDA composite powder, 0.6g of UV absorber (CAS No.: 1843-05-6), and 0.5g of hindered amine light stabilizer (CAS No.: 82919-37-7) were added sequentially. The mixture was dry-mixed at 1000rpm for 14min at room temperature, and then fed into a twin-screw extruder. The mixture was melt-mixed at 160℃ for 5min. Subsequently, the barrel temperature was adjusted to 120℃ in the rear section of the twin-screw extruder, and 45g of paraffin microcapsules (the core material was paraffin with a melting point of 25℃, and the shell material was polymethyl methacrylate, purchased from Hubei Saimo New Energy Technology Co., Ltd.) were added. The mixture was melt-mixed for another 2.2min, extruded, calendered into sheets, and cooled and cured to obtain a PVB-based photothermal phase change intermediate film (thickness of 0.8mm).

[0057] Low-iron float glass was used as the substrate and was ultrasonically cleaned in propanol, anhydrous ethanol, and deionized water for 12 minutes in sequence. It was then dried at 65°C for 35 minutes to obtain a pretreated glass substrate. The obtained PVB-based photothermal phase change interlayer was cut into pieces with an edge size 2.3 mm smaller than the edge size of the pretreated glass substrate. One piece of pretreated glass substrate was placed flat on a stainless steel table covered with a silicone pad. The interlayer was then laid flat on the surface of the glass, and a second piece of pretreated glass substrate was placed on top of the interlayer. After the two pieces of glass were completely bonded together through the interlayer, they were sent into a vacuum pre-pressing device and held at a vacuum degree of -0.07 MPa and 80°C for 12 minutes. After that, the pre-composite blank was rolled and placed in an autoclave. The blank was heated to 140°C and held at 1.2 MPa for 50 minutes. After that, the blank was slowly cooled to 50°C and then allowed to cool naturally to room temperature. The blank was then trimmed and polished to obtain laminated glass.

[0058] 3.2 g of hydrophobic fumed silica (particle size 7 nm, CAS No.: 68909-20-6) was added to 500 mL of anhydrous ethanol, magnetically stirred for 25 min, and then ultrasonically dispersed for 25 min. Under continuous stirring, 0.4 mL of 0.01 mol / L ammonia water and 1.2 mL of 1H,1H,2H,2H-perfluorodecyltrimethoxysilane (CAS No.: 83048-65-1) were added dropwise, and the mixture was stirred for 7 h and ultrasonically dispersed for 40 min to obtain an HF-SiO2 suspension. 6.7 g of cesium tungsten bronze powder (Cs) was added... x WO3 (CAS No.: 189619-69-0) and 0.35 g of polyvinylpyrrolidone were added to 260 mL of deionized water and ultrasonically dispersed for 120 min to obtain Cs. x WO3 dispersion; 30g polyvinyl alcohol was added to 260mL deionized water and magnetically stirred at 80℃ for 2h, then Cs was added. x The WO3 dispersion was further stirred magnetically for 70 minutes to obtain Cs. x WO3 coating solution; the above Cs x WO3 coating solution is poured onto the outer surface of laminated glass, coated into a film, and dried at 80°C for 50 minutes to form Cs on the outer surface. x WO3 coating (Cs) x The WO3 coating (4.5 μm thick) was fixed on the spraying platform, and the HF-SiO2 suspension was uniformly sprayed onto the Cs. x The WO3 coating surface is dried at 130℃ for 80 min to form an HF-SiO2 outer layer (HF-SiO2 outer layer thickness is 0.5μm), thus producing solar thermal glass.

[0059] Example 4

[0060] 0.9 g of nano zinc oxide powder and 0.6 g of hexagonal boron nitride nano powder were added to 480 mL of 50% (v / v) ethanol aqueous solution and ultrasonically dispersed for 32 min to obtain ZnO / h-BN dispersion. 650 mL of deionized water and 1.8 g of dopamine hydrochloride were mixed evenly, and the pH of the solution was slowly adjusted to 8.2 using NaHCO3. The ZnO / h-BN dispersion was slowly added and magnetically stirred for 11.5 h. After centrifugation at 7000 rpm for 15 min, the supernatant was removed, and the precipitate was washed three times successively with deionized water and anhydrous ethanol. The precipitate was vacuum dried at 72 °C for 13 h, ground, and sieved (using a 200-mesh sieve) to obtain ZnO / h-BN@PDA composite powder.

[0061] 200g of PVB resin powder was placed in a high-speed mixer, and 40g of trioctyl trimellitate, 1.4g of ZnO / h-BN@PDA composite powder, 0.47g of UV absorber (CAS No.: 1843-05-6), and 0.42g of hindered amine light stabilizer (CAS No.: 82919-37-7) were added sequentially. The mixture was dry-mixed at 900rpm for 12min at room temperature, and then fed into a twin-screw extruder. The mixture was melt-mixed at 150℃ for 4min. Subsequently, the barrel temperature was adjusted to 110℃ in the rear section of the twin-screw extruder, and 42g of paraffin microcapsules (the core material was paraffin with a melting point of 25℃, and the shell material was polymethyl methacrylate, purchased from Hubei Saimo New Energy Technology Co., Ltd.) were added. The mixture was melt-mixed for another 3min, extruded, calendered into sheets, and cooled and cured to obtain a PVB-based photothermal phase change intermediate film (thickness of 0.77mm).

[0062] Low-iron float glass was used as the substrate and was ultrasonically cleaned in propanol, anhydrous ethanol, and deionized water for 14 minutes in sequence. It was then dried at 60°C for 32 minutes to obtain a pretreated glass substrate. The obtained PVB-based photothermal phase change interlayer was cut into pieces with an edge size 2.5 mm smaller than the edge size of the pretreated glass substrate. One piece of pretreated glass substrate was placed flat on a stainless steel table covered with a silicone pad. The interlayer was then laid flat on the surface of the glass, and a second piece of pretreated glass substrate was placed on top of the interlayer. After the two pieces of glass were completely bonded together through the interlayer, they were sent into a vacuum pre-pressing device and held at a vacuum degree of -0.06 MPa and 75°C for 16 minutes. After that, the pre-composite blank was rolled and placed in an autoclave. The blank was heated to 135°C and held at 0.9 MPa for 40 minutes. After that, the blank was slowly cooled to 50°C and then allowed to cool naturally to room temperature. The blank was then trimmed and polished to obtain laminated glass.

[0063] 3g of hydrophobic fumed silica (particle size 7nm, CAS No.: 68909-20-6) was added to 480mL of anhydrous ethanol, magnetically stirred for 27min, and then ultrasonically dispersed for 27min. Under continuous stirring, 0.33mL of 0.01mol / L ammonia and 1mL of 1H,1H,2H,2H-perfluorodecyltrimethoxysilane (CAS No.: 83048-65-1) were added dropwise, and the mixture was stirred for 7h and ultrasonically dispersed for 30min to obtain an HF-SiO2 suspension. 6.4g of cesium tungsten bronze powder (Cs) was added... x WO3 (CAS No.: 189619-69-0) and 0.28 g of polyvinylpyrrolidone were added to 245 mL of deionized water and ultrasonically dispersed for 110 min to obtain Cs. x WO3 dispersion: 27g polyvinyl alcohol was added to 245mL deionized water and magnetically stirred at 78℃ for 2.5h. Cs was then added. x The WO3 dispersion was further stirred magnetically for 70 minutes to obtain Cs. x WO3 coating solution; the above Cs x WO3 coating solution is poured onto the outer surface of laminated glass, coated into a film, and dried at 70°C for 50 minutes to form Cs on the outer surface. x WO3 coating (Cs) x The WO3 coating (4 μm thick) was fixed on the spraying platform, and the HF-SiO2 suspension was uniformly sprayed onto the Cs. x The WO3 coating surface is dried at 125℃ for 70 min to form an HF-SiO2 outer layer (HF-SiO2 outer layer thickness is 0.4μm), thus producing solar thermal glass.

[0064] Example 5

[0065] 0.9 g of nano zinc oxide powder and 0.6 g of hexagonal boron nitride nano powder were added to 520 mL of 50% (v / v) ethanol aqueous solution and ultrasonically dispersed for 35 min to obtain ZnO / h-BN dispersion. 700 mL of deionized water and 1.8 g of dopamine hydrochloride were mixed evenly, and the pH of the solution was slowly adjusted to 8.5 using NaHCO3. The ZnO / h-BN dispersion was slowly added and magnetically stirred for 11 h. After centrifugation at 7000 rpm for 18 min, the supernatant was removed, and the precipitate was washed twice with deionized water and anhydrous ethanol, respectively. The precipitate was vacuum dried at 72 °C for 14 h, ground, and sieved (using a 200-mesh sieve) to obtain ZnO / h-BN@PDA composite powder.

[0066] 210g of PVB resin powder was placed in a high-speed mixer, and 55g of trioctyl trimellitate, 1.2g of ZnO / h-BN@PDA composite powder, 0.55g of UV absorber (CAS No.: 1843-05-6), and 0.35g of hindered amine light stabilizer (CAS No.: 82919-37-7) were added sequentially. The mixture was dry-mixed at 850rpm for 12min at room temperature, and then fed into a twin-screw extruder. The mixture was melt-mixed at 155℃ for 4.5min. Subsequently, the barrel temperature was adjusted to 115℃ in the rear section of the twin-screw extruder, and 48g of paraffin microcapsules (the core material was paraffin with a melting point of 30℃, and the shell material was polymethyl methacrylate, purchased from Hubei Saimo New Energy Technology Co., Ltd.) were added. The mixture was melt-mixed for another 3min, extruded, calendered into sheets, and cooled and cured to obtain a PVB-based photothermal phase change intermediate film (thickness of 0.8mm).

[0067] Low-iron float glass was used as the substrate and was ultrasonically cleaned in propanol, anhydrous ethanol, and deionized water for 12 minutes in sequence. It was then dried at 58°C for 38 minutes to obtain a pretreated glass substrate. The obtained PVB-based photothermal phase change interlayer was cut into pieces with an edge size 2.1 mm smaller than the edge size of the pretreated glass substrate. One piece of pretreated glass substrate was placed flat on a stainless steel table covered with a silicone pad. The interlayer was then laid flat on the surface of the glass, and a second piece of pretreated glass substrate was placed on top of the interlayer. After the two pieces of glass were completely bonded together through the interlayer, they were sent into a vacuum pre-pressing device and held at a vacuum degree of -0.08 MPa and 60°C for 12 minutes. After that, the pre-composite blank was rolled and placed in an autoclave. The blank was heated to 130°C and held at 1.2 MPa for 50 minutes. After that, the blank was slowly cooled to 50°C and then allowed to cool naturally to room temperature. The blank was then trimmed and polished to obtain laminated glass.

[0068] 3.1 g of hydrophobic fumed silica (particle size 7 nm, CAS No.: 68909-20-6) was added to 400 mL of anhydrous ethanol, magnetically stirred for 30 min, and then ultrasonically dispersed for 20 min. Under continuous stirring, 0.32 mL of 0.01 mol / L ammonia water and 1.1 mL of 1H,1H,2H,2H-perfluorodecyltrimethoxysilane (CAS No.: 83048-65-1) were added dropwise, and the mixture was stirred for 6 h and ultrasonically dispersed for 40 min to obtain an HF-SiO2 suspension. 6.2 g of cesium tungsten bronze powder (Cs) was added... x WO3 (CAS No.: 189619-69-0) and 0.35 g of polyvinylpyrrolidone were added to 240 mL of deionized water and ultrasonically dispersed for 120 min to obtain Cs. x WO3 dispersion; 25g polyvinyl alcohol was added to 260mL deionized water and magnetically stirred at 70℃ for 3h, then Cs was added. x The WO3 dispersion was further magnetically stirred for 60 minutes to obtain Cs.x WO3 coating solution; the above Cs x WO3 coating solution is poured onto the outer surface of laminated glass, coated into a film, and dried at 80℃ for 30 minutes to form Cs on the outer surface. x WO3 coating (Cs) x The WO3 coating (4.2 μm thick) was fixed on the spraying platform, and the HF-SiO2 suspension was uniformly sprayed onto the Cs. x The WO3 coating surface was dried at 127℃ for 75 min to form an HF-SiO2 outer layer (HF-SiO2 outer layer thickness was 0.25μm), thus producing solar thermal glass.

[0069] Example 6

[0070] 0.9 g of nano zinc oxide powder and 0.7 g of hexagonal boron nitride nano powder were added to 460 mL of 50% (v / v) ethanol aqueous solution and ultrasonically dispersed for 40 min to obtain ZnO / h-BN dispersion. 800 mL of deionized water and 2 g of dopamine hydrochloride were mixed evenly, and the pH of the solution was slowly adjusted to 8.6 using NaHCO3. The ZnO / h-BN dispersion was slowly added and magnetically stirred for 10 h. After centrifugation at 6000 rpm for 20 min, the supernatant was removed, and the precipitate was washed twice with deionized water and anhydrous ethanol, respectively. The precipitate was vacuum dried at 70 °C for 16 h, ground, and sieved (using a 200-mesh sieve) to obtain ZnO / h-BN@PDA composite powder.

[0071] 180g of PVB resin powder was placed in a high-speed mixer, and 35g of trioctyl trimellitate, 0.8g of ZnO / h-BN@PDA composite powder, 0.6g of UV absorber (CAS No.: 1843-05-6), and 0.3g of hindered amine light stabilizer (CAS No.: 82919-37-7) were added sequentially. The mixture was dry-mixed at 1000rpm for 15min at room temperature, and then fed into a twin-screw extruder. The mixture was melt-mixed at 160℃ for 3min. Subsequently, the barrel temperature was adjusted to 120℃ in the rear section of the twin-screw extruder, and 40g of paraffin microcapsules (the core material was paraffin with a melting point of 25℃, and the shell material was polymethyl methacrylate, purchased from Hubei Saimo New Energy Technology Co., Ltd.) were added. The mixture was melt-mixed for another 2min, extruded, calendered into sheets, and cooled and cured to obtain a PVB-based photothermal phase change intermediate film (thickness of 0.8mm).

[0072] Low-iron float glass was used as the substrate and was ultrasonically cleaned in propanol, anhydrous ethanol, and deionized water for 12 minutes in sequence. It was then dried at 60°C for 35 minutes to obtain a pretreated glass substrate. The obtained PVB-based photothermal phase change interlayer was cut into pieces with an edge size 2.8 mm smaller than the edge size of the pretreated glass substrate. One piece of pretreated glass substrate was placed flat on a stainless steel table covered with a silicone pad. The interlayer was then laid flat on the surface of the glass, and a second piece of pretreated glass substrate was placed on top of the interlayer. After the two pieces of glass were completely bonded together through the interlayer, they were sent into a vacuum pre-pressing device and held at a vacuum degree of -0.08 MPa and 60°C for 20 minutes. After that, the pre-composite blank was rolled and placed in an autoclave. The blank was heated to 132°C and held at a pressure of 1.2 MPa for 55 minutes. After that, the blank was slowly cooled to 50°C and then allowed to cool naturally to room temperature. The blank was then trimmed and polished to obtain laminated glass.

[0073] 6.4g of cesium tungsten bronze powder (Cs x WO3 (CAS No.: 189619-69-0) and 0.32 g of polyvinylpyrrolidone were added to 255 mL of deionized water and ultrasonically dispersed for 115 min to obtain Cs. x WO3 dispersion: Add 28g of polyvinyl alcohol to 255mL of deionized water, stir magnetically at 77℃ for 2.5h, then add Cs. x The WO3 dispersion was further magnetically stirred for 68 minutes to obtain Cs. x WO3 coating solution; the above Cs x WO3 coating solution is poured onto the outer surface of laminated glass, coated into a film, and dried at 75°C for 35 minutes to form Cs on the outer surface. x WO3 coating (Cs) x A solar thermal glass was prepared by coating a WO3 layer with a thickness of 5 μm.

[0074] The present invention also includes comparative examples and related experiments.

[0075] Comparative Example 1

[0076] Compared with Example 1, the only difference is that ZnO / h-BN@PDA composite powder was not added to the PVB-based photothermal phase change intermediate film. The other preparation methods and components are completely consistent, and solar thermal glass is finally obtained.

[0077] Comparative Example 2

[0078] Compared with Example 1, the only difference is that no paraffin microcapsules were added to the PVB-based photothermal phase change intermediate film. The other preparation methods and components are completely consistent, and solar thermal glass is finally obtained.

[0079] Comparative Example 3

[0080] Compared with Example 1, the only difference is that the laminated glass produced is used directly as solar thermal glass.

[0081] Performance testing

[0082] First, the solar thermal glass samples prepared in Examples 1-6 and Comparative Examples 1-3 were tested for light transmittance, photothermal conversion efficiency, anti-aging performance and self-cleaning performance.

[0083] (1) Light transmittance test: The light transmittance was tested according to the method of GB / T2680-2021 "Determination of visible light transmittance, direct solar transmittance, total solar transmittance, ultraviolet transmittance and related window glass parameters of architectural glass" and the light transmittance A0 was obtained.

[0084] (2) Photothermal conversion efficiency test: Refer to the test method of GB / T30592-2014 "Detection of solar heat gain coefficient of light-transmitting enclosure structure using artificial simulated light source", the specific steps are as follows: fix a 2mm thick black anodized aluminum plate at the opening of the heat preservation box, attach a K-type thermocouple to the back of the aluminum plate, and insulate the surrounding area with polyurethane foam; cover the outside of the black aluminum plate with the solar thermal glass samples prepared in Examples 1-6 and Comparative Examples 1-3, so that the glass and the aluminum plate are tightly attached, with Cs x The WO3 coating side faces the light source. A solar simulator with AM1.5 spectrum was used to adjust the horizontal total irradiance on the sample surface to 1000 W / m². 2 The sample was continuously irradiated at 30°C for 100 minutes, and the following tests were conducted: ① bare blackboard without glass; ② covered with ordinary low-iron float glass; ③ covered with the solar thermal glass prepared in Examples 1-6 and Comparative Examples 1-3. The ambient temperature T was used as the reference. a Based on this, the stable temperatures of the black anodized aluminum plate at thermal equilibrium under various operating conditions are defined as T0 (bare plate) and T... c (Ordinary glass) and T s (The solar thermal glass sample to be tested), the formula for calculating the photothermal conversion efficiency (%) is as follows:

[0085] Photothermal conversion efficiency = ((T) s -T a ) / (T0-T a ))×100%

[0086] (3) Anti-aging performance test: The solar thermal glass prepared in Examples 1-6 and Comparative Examples 1-3 was placed in an ultraviolet aging chamber and irradiated with ultraviolet radiation that meets the requirements of IEC61215 until the ultraviolet radiation in the wavelength range of 280nm~400nm reached 121.0kWh / m 2Measure the transmittance A1 again, and calculate the transmittance retention rate (%) based on (1). The specific calculation formula is as follows:

[0087] Light transmittance retention rate = (A1 / A0) × 100%

[0088] (4) Self-cleaning performance test: The same mass of carbon powder was used as a contaminant and evenly spread on the solar thermal glass samples prepared in Examples 1-6 and Comparative Examples 1-3. A small amount of water was drawn up with a dropper and dripped onto the carbon powder. After the water droplets settled on the glass sample, the glass sample was tilted to observe the water marks and the carbon powder residue on the sample surface.

[0089] The performance test results are shown in Table 1.

[0090] Table 1

[0091]

[0092] As shown in Table 1, the solar thermal glass prepared in Examples 1 to 5 of the present invention maintains high light transmittance while also possessing good photothermal conversion efficiency, anti-aging properties, and self-cleaning properties.

[0093] Among them, the light transmittance A0 of Examples 1 to 6 are all in the range of 80.3% to 89.6%, which can meet the requirements of light collection and visibility; and the light transmittance retention rate of the solar thermal glass prepared in Examples 1 to 5 is all in the range of 94% to 96%. The light transmittance retention rate of Example 6 is slightly worse due to the absence of the HF-SiO2 outer layer, but it is still significantly better than that of Comparative Examples 1 to 3. The absence of ZnO / h-BN@PDA composite powder in Comparative Example 1 and the lack of further coating on the outer surface of the solar thermal glass in Comparative Example 3 resulted in a significant decrease in light transmittance retention rate. Furthermore, the solar thermal glass prepared in Examples 1-6 all exhibited good photothermal conversion efficiency, further demonstrating its high solar thermal utilization efficiency, significantly superior to Comparative Examples 1-3. Among them, the lack of ZnO / h-BN@PDA composite powder in Comparative Example 1 and the absence of further coating on the outer surface of the solar thermal glass in Comparative Example 3 resulted in a significant decrease in efficiency. The presence of watermarks and stains on the outer surface after the self-cleaning performance test also clearly shows that the solar thermal glass prepared in Example 6 lacked a HF-SiO2 outer layer and Comparative Example 3 lacked an outer layer, resulting in the absence of self-cleaning performance.

[0094] In addition, the solar thermal glass samples prepared in Examples 1-6 and Comparative Examples 1-3 were subjected to a temperature cycling test of 0-60°C. The heating, constant temperature and cooling stages were maintained for 1 hour each, for a total of 150 cycles. After the test, the appearance of the samples was visually tested to see if there were any phenomena such as blistering, delamination, or cracking. The specific test results are shown in Table 2. "√" indicates that the sample obviously has the corresponding defects, and "×" indicates that the sample does not obviously have the corresponding defects.

[0095] Table 2

[0096]

[0097] As shown in Table 2, the samples of Examples 1-6 of this invention maintained good condition after 150 temperature cycles, while the sample of Comparative Example 2 showed obvious blistering and delamination after 150 temperature cycles. This indicates that the introduction of paraffin microcapsules into the intermediate film of this invention can buffer temperature differences through the latent heat of phase change during temperature changes, thereby improving the overall service life of the material. Furthermore, in the above performance test (2) photothermal conversion efficiency test, the temperatures (T) of the black anodized aluminum plate samples of Examples 1 and Comparative Example 2 were... t The curve showing the change over time is as follows: Figure 1 As shown, from Figure 1 It can also be clearly seen that the temperature rise rate of Comparative Example 2 is significantly faster than that of Example 1. In Example 1, due to the introduction of paraffin microcapsules in the intermediate membrane, the temperature rise process is relatively slow, but after continuous irradiation by the light source and reaching thermal equilibrium, the final stable temperature is higher than that of Comparative Example 2.

[0098] In summary, the solar thermal glass prepared in Examples 1-5 of this invention maintains good light transmittance while improving photothermal conversion efficiency and anti-aging properties, and has a certain self-cleaning function. It can be well applied to curtain wall energy saving and indoor temperature regulation.

[0099] The above are preferred embodiments of the present invention. Those skilled in the art can make several improvements and modifications without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing solar thermal glass, characterized in that, Includes the following steps: S1. PVB resin powder, ZnO / h-BN@PDA composite powder and additives are dry mixed and fed into a twin-screw extruder. After melting and mixing at 140~160℃, the temperature is adjusted to 100~120℃, paraffin microcapsules are added, and melting and mixing are continued. The mixture is then extruded, calendered into sheets, cooled and solidified to obtain a PVB-based photothermal phase change intermediate film. S2. Lay the interlayer film flat on the surface of a pretreated glass substrate, then cover the interlayer film with a second pretreated glass substrate. After vacuum heating and pre-pressing, place it in an autoclave, heat it up, press it under high pressure, let it cool naturally to room temperature, and then trim and polish it to obtain laminated glass. S3, Cs x WO3 coating solution is poured onto the outer surface of laminated glass, coated into a film, heated and dried to form Cs on the outer surface. x WO3 coating is used to produce solar thermal glass; The ZnO / h-BN@PDA composite powder is obtained by mixing 500-800 parts by volume of deionized water and 1.5-2 parts by mass of dopamine hydrochloride, slowly adjusting the pH of the solution to 8.0-8.7 with NaHCO3, slowly adding ZnO / h-BN dispersion and magnetically stirring for 10-12 hours, centrifuging at 6000-8000 rpm for 10-20 minutes, discarding the supernatant, washing the precipitate with deionized water and anhydrous ethanol 2-3 times sequentially, vacuum drying at 70-80℃ for 12-16 hours, grinding, and sieving. The ZnO / h-BN dispersion is obtained by adding 0.8-1.2 parts by mass of nano zinc oxide powder and 0.4-0.7 parts by mass of hexagonal boron nitride nano powder to 450-550 parts by volume of 50% ethanol aqueous solution and ultrasonically dispersing for 30-40 minutes.

2. The method for preparing solar thermal glass according to claim 1, characterized in that, In step S1, 180-230 parts by weight of PVB resin powder, 0.8-1.5 parts by weight of ZnO / h-BN@PDA composite powder, and additives are dry-mixed at 800-1000 rpm for 10-15 minutes at room temperature, then fed into a twin-screw extruder and melt-mixed at 140-160°C for 3-5 minutes. Subsequently, the barrel temperature is adjusted to 100-120°C in the rear section of the twin-screw extruder, and 40-55 parts by weight of paraffin microcapsules are added and melt-mixed for another 2-3 minutes. The mixture is then extruded, calendered into sheets, cooled, and cured to obtain a PVB-based photothermal phase change intermediate film. The additives are 35-60 parts by weight of trioctyl trimellitate, 0.4-0.6 parts by weight of UV absorber, and 0.3-0.5 parts by weight of hindered amine light stabilizer.

3. The method for preparing solar thermal glass according to claim 1, characterized in that, The pretreated glass substrate is obtained by ultrasonically cleaning low-iron float glass in propanol, anhydrous ethanol and deionized water for 10-15 min in sequence, and drying at 55-65℃ for 30-40 min.

4. The method for preparing solar thermal glass according to claim 1, characterized in that, In step S2, a pre-treated glass substrate is laid flat on a stainless steel table covered with a silicone pad. An interlayer film is laid flat on the surface of the pre-treated glass substrate, and then a second pre-treated glass substrate is placed on top of the interlayer film. After the two glass substrates are completely bonded together through the interlayer film, they are sent into a vacuum pre-pressing device and kept at a vacuum degree of -0.08 to -0.06 MPa and a temperature of 60 to 80°C for 10 to 20 minutes. The pre-composite blank is then rolled and placed in an autoclave and heated to 130 to 140°C. It is then held at a pressure of 0.8 to 1.2 MPa for 30 to 60 minutes, slowly cooled to 50°C, and then allowed to cool naturally to room temperature. The edges are then trimmed and polished to obtain laminated glass.

5. The method for preparing solar thermal glass according to claim 1, characterized in that, The Cs x The WO3 coating solution is prepared by adding 25-30 parts by weight of polyvinyl alcohol to 240-260 parts by volume of deionized water, and magnetically stirring at 70-80°C for 1.5-3 hours. Cs is then added. x The WO3 dispersion was further magnetically stirred for 60-80 minutes to obtain the Cs. x The WO3 dispersion was obtained by adding 6.2-6.7 parts by weight of cesium tungsten bronze powder and 0.25-0.35 parts by weight of polyvinylpyrrolidone to 240-260 parts by volume of deionized water and ultrasonically dispersing for 100-120 minutes.

6. The method for preparing solar thermal glass according to claim 1, characterized in that, In step S3, the heating and drying time is 30-60 minutes and the temperature is 60-80°C; Cs is formed on the outer surface during high-temperature drying. x After the WO3 coating, an HF-SiO2 suspension was used to spray the outer surface, uniformly spraying the HF-SiO2 suspension onto the Cs. x The WO3 coating surface is dried at 120~130℃ for 60~80min to form an HF-SiO2 outer layer, and finally solar thermal glass is obtained.

7. The method for preparing solar thermal glass according to claim 6, characterized in that, The HF-SiO2 suspension was obtained by adding 2.8-3.2 parts by mass of fumed silica to 400-500 parts by volume of anhydrous ethanol, stirring magnetically for 20-30 min, followed by ultrasonic dispersion for 20-30 min, and then adding 0.3-0.4 parts by volume of 0.01 mol / L ammonia water and 0.8-1.2 parts by volume of 1H,1H,2H,2H-perfluorodecyltrimethoxysilane dropwise while stirring for 6-8 h and ultrasonication for 20-40 min.

8. A solar thermal glass, characterized in that, It is prepared using the method for preparing solar thermal glass according to any one of claims 1 to 7.

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