Intelligent thermal regulation semi-transparent energy production and energy saving film for building and preparation method thereof

Abstract

The application discloses a kind of semi-transparent energy production and energy saving films of intelligent heat regulation for building and preparation method thereof, the semi-transparent energy production and energy saving films include in turn from inside to outside of building: transparent film substrate, phase change composite layer, first transparent layer, photoelectric layer, second transparent layer, transparent film encapsulation protective layer;The phase change composite layer is the composite of phase change material nanoparticles and resin material, the first transparent layer and the second transparent layer are all silver nanowire cross grid structure layer.The energy production and energy saving film of the application can not only sunshade heat insulation, optimize natural lighting, dynamically adjust infrared transmittance (1000-2500nm) to save building energy consumption, but also can absorb ultraviolet (300-380nm), part visible (380-760nm) and near infrared band (760-1000nm) sunlight energy production to build building operation and maintenance.Especially, it can realize efficient photo-thermal regulation and efficient photoelectric conversion in large space range using natural light, with the advantages of thin structure, simple manufacturing process, etc., which can be widely applied in large space buildings.

Description

Technical Field

[0001] This invention belongs to the field of membrane structure building materials technology, and relates to a semi-transparent membrane for building and its preparation method, and more particularly to a semi-transparent energy-saving membrane with intelligent thermal regulation for building and its preparation method. Background Technology

[0002] Membrane structures, particularly in large-span buildings, are architectural systems where membrane materials serve as the tensioning element, working in conjunction with supporting components or cables. With their novel and unique architectural forms and excellent load-bearing characteristics, membrane structures have become one of the main forms of large-span spatial building structures. Due to the advantages of membrane materials, such as lightweight and flexible shapes, aesthetic appeal, light transmission, energy efficiency, environmental friendliness, excellent flame retardancy, stain resistance and self-cleaning properties, safety, and long lifespan, they are widely used in large-span, large-span buildings such as sports facilities, shopping malls, exhibition centers, and transportation service facilities. However, unlike buildings of ordinary scale, large-span public buildings are characterized by their enormous scale, unique structure, open interfaces, and complex operation, resulting in a significant proportion of energy and material consumption in total building energy consumption. On the one hand, scale limits the efficiency of energy and material exchange with the environment; when the building scale reaches a critical value, the original building regulation mechanisms can no longer meet its needs for environmental adaptation. Simultaneously, due to the high permeability of membrane materials, solar radiation is more likely to affect the indoor thermal environment of membrane structures compared to ordinary buildings. Therefore, in order to promote the construction of green cities in the future, it is urgent to develop new energy-saving space temperature control and in-situ energy harvesting technologies for the green design of large-space buildings, so as to reduce the energy consumption of space temperature control and optimize the energy supply structure, thereby achieving energy conservation and emission reduction.

[0003] Solar radiation is Earth's primary energy source. Building-integrated photovoltaics (BIPV) is a technology that integrates solar power generation (photovoltaic) products into buildings. Solar photovoltaic arrays are installed on the exterior surface of the building envelope to provide electricity, representing a new concept and method for applying solar power. However, the unique material and structural characteristics of membrane structures mean that current mainstream BIPV products cannot be directly applied to their surfaces. Therefore, although the application of membrane structures in large public buildings has developed rapidly recently, their photovoltaic integration has been neglected, and suitable products are lacking in the market. Currently, the most common silicon crystalline solar cells are widely used in BIPV, but their rigidity, appearance, efficiency, and installation limitations greatly restrict their application scenarios, making it difficult to integrate with the overall design of membrane structure buildings and preventing the achievement of semi-transparency. Thin-film solar cells are a newly emerging mainstream application in the industry, offering advantages such as flexibility, high efficiency, thinness, and small footprint. Examples include amorphous silicon, cadmium telluride (CdTe), copper zinc tin sulfide (CZTSSe), dye-sensitized (CIGS), and perovskite solar cells. However, their strong visible light absorption makes them difficult to apply directly to transparent structures. Only by significantly sacrificing power generation performance and combining micro / nano structure design with laser etching technology can a certain degree of light transmittance be achieved. Therefore, this invention proposes a smart, thermally regulated, semi-transparent, energy-saving membrane that can be well applied in membrane structure buildings. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this application provides a semi-transparent, energy-saving membrane for intelligent thermal control in buildings and its preparation method. This membrane can efficiently utilize solar energy and, when applied to buildings, can intelligently regulate indoor lighting, temperature comfort, and operating energy consumption.

[0005] The technical solution adopted in this application is as follows:

[0006] The semi-transparent energy-saving membrane for intelligent thermal regulation in buildings comprises, from the inside to the outside of the building: a transparent thin film substrate, a first transparent layer, a photoelectric layer, a second transparent layer, and a transparent encapsulation and protection layer; or a phase change composite layer is provided between the transparent thin film substrate and the first transparent layer; the phase change composite layer is a composite of phase change material nanoparticles and resin materials, and the first transparent layer and the second transparent layer are both silver nanowire cross-grid structure layers.

[0007] In the above technical solution, the transparent film is further made of one or more materials such as ETFE, PTFE, and PVC.

[0008] Furthermore, the phase change composite layer is specifically a mixed film of phase change material nanoparticles and resin material, wherein the mass percentage of nanoparticles is 1-10 wt% and the thickness of the phase change composite layer is 10-100 μm.

[0009] Furthermore, the phase change material nanoparticles are one or a mixture of several of the following nanoparticles: VO2, W-VO2, WO3, SiO2, Co3O4, TiO2, Al2O3, etc., with a nanoparticle size of 50-150 nm. The resin material is one or a mixture of several of the following: TPU, PE, ETFE, PVC, EVA, etc.

[0010] Furthermore, the silver nanowire cross-grid structure layer is formed by repeatedly and uniformly coating and stacking silver nanowire dispersions.

[0011] Furthermore, the photoelectric layer is a stacked structure of PEDOT:PSS, an organic hybrid film, and AZO, wherein the organic hybrid film is a mixture of PM6 and Y6. The corresponding thicknesses are typically 10-100 nm, 100-500 nm, and 10-100 nm.

[0012] Furthermore, the mass ratio of PM6 to Y6 is 1:n, where 1 < n < 50.

[0013] Furthermore, the transparent encapsulation protective layer is one or a mixture of several of TPU, PE, ETFE, PVC, EVA, etc.

[0014] A method for preparing a semi-transparent, energy-saving, and heat-regulating intelligent thermal control film for buildings, comprising the following steps:

[0015] 1) Clean the flat transparent thin film substrate with water using ultrasonic cleaning and then treat it with ultraviolet ozone.

[0016] 2) After drying the film obtained in step 1), spin-coat a mixture of phase change material nanoparticles and resin material, and then dry it; or omit step 2) and proceed directly to step 3).

[0017] 3) Stack the film obtained in step 2) layer by layer to form a silver nanowire mesh structure layer by spin coating silver nanowire dispersion multiple times at multiple speeds, and anneal at 150°C for 15 minutes.

[0018] 4) After treating the film obtained in step 3) with ultraviolet ozone, spin-coat PEDOT:PSS and anneal at 110°C for 15 minutes.

[0019] 5) The film obtained in step 4) is spin-coated in an inert gas atmosphere to prepare an organic hybrid film containing PM6 and Y6, and then annealed at 100°C for 10 minutes.

[0020] 6) Spin-coat the AZO layer onto the thin film obtained in step 5) and anneal it at 60°C for 8 minutes;

[0021] 7) Stack the film obtained in step 6) layer by layer to form a silver nanowire mesh structure layer by spin coating silver nanowire dispersion multiple times at multiple speeds, and anneal at 150°C for 15 minutes.

[0022] 8) Encapsulate and protect the film obtained in step 7) with a transparent film material.

[0023] Furthermore, the solvent in the phase change material nanoparticle and resin material mixed solution, the solvent in the spin-coating solution for spin-coating PEDOT:PSS, spin-coating AZO, and spin-coating to prepare organic mixed films, and the solvent in the silver nanowire dispersion are one or a mixture of several of the following: water, ethanol, ethylene glycol, acetone, isopropanol, DMF, chlorobenzene, and chloroform.

[0024] Solar radiation refers to the energy transmitted outward by the sun through electromagnetic waves emitted into space. Solar radiation is mainly divided into three regions according to wavelength: the visible light region, the infrared region, and the ultraviolet region. Wavelengths greater than 0.76 μm are called the infrared region, those less than 0.38 μm are called the ultraviolet region, and those between 0.38 μm and 0.76 μm are called the visible light region. Although the amount of radiation received by the Earth accounts for only one two-billionth of the weight of solar radiation, this portion of radiation is the Earth's primary energy source. Therefore, the rational utilization of solar radiation to provide natural energy for the operation and maintenance, temperature regulation, and other functions of membrane structure buildings is an important direction for future green city construction and green design of large-space buildings.

[0025] The beneficial effects of this application are:

[0026] The membrane of this invention gives buildings a lightweight feel. The excellent semi-permeability of the membrane structure allows light to pass through the building interface while preventing transparency. For different wavelengths of solar radiation, the transmitted visible light (380-760nm) can be used for lighting, while ultraviolet light (300-380nm) and some visible (380-760nm) / near-infrared (760-1000nm) sunlight can be used for power generation. Alternatively, the remaining near-infrared wavelengths (1000-2500nm) of sunlight can be used for heat regulation. It can provide shading and heat insulation, optimize natural lighting, and dynamically adjust infrared transmittance to save building energy. Especially when applied to membrane structure buildings, it can achieve efficient light and heat regulation of large spaces using natural light. In summer, it can prevent heat-accumulating infrared light from entering the building through the membrane; in winter, it allows light to enter while preventing indoor heat loss, thus warming the building. The membrane of this invention can make full use of daytime sunlight for temperature control and energy supply within membrane structure buildings. It has advantages such as lightweight structure and simple manufacturing process, and can be widely applied to large-space buildings, especially membrane structure buildings. Attached Figure Description

[0027] Figure 1This is a schematic diagram of a semi-transparent energy-saving membrane for intelligent thermal control in buildings, as described in an embodiment of this application.

[0028] Figure 2 The absorption spectra of a semi-transparent energy-saving membrane for building intelligent thermal regulation with different Y6 to PM6 mass ratios n are shown in the embodiments of this application.

[0029] Figure 3 Absorption spectra of a semi-transparent energy-saving membrane with intelligent thermal regulation under different temperature environments.

[0030] Figure 4 Absorption spectrum of a semi-transparent, energy-saving membrane for intelligent thermal regulation in buildings without phase change composite layers;

[0031] Figure 5 SEM image of a large-area silver nanowire cross-grid structure layer;

[0032] Figure 6 Periodic bending test of a large-area silver nanowire cross-grid structure layer;

[0033] Figure 7 This is a schematic diagram illustrating the working principle of a semi-transparent energy-saving membrane for intelligent thermal control in buildings, as described in this application. Detailed Implementation

[0034] To better understand the above technical solutions, the following will provide a detailed explanation of the technical solutions in conjunction with the accompanying drawings and specific implementation methods.

[0035] This application relates to a semi-transparent, energy-saving membrane for intelligent thermal control in buildings, such as... Figure 1 As shown, from the inside to the outside of the building, it includes: a transparent thin film substrate 1, a phase change composite layer 2, a first transparent layer 3, a photoelectric layer 4, a second transparent layer 5, and a transparent encapsulation protective layer 6; the phase change composite layer is a composite material of phase change material nanoparticles and resin, and the first transparent layer and the second transparent layer are both silver nanowire cross-grid structure layers.

[0036] In one specific embodiment of this application, the transparent film is an ETFE film with a thickness typically of 50-250 μm; it not only has high light transmittance (greater than 90%), but also excellent impact resistance, thermal stability, corrosion resistance, and high mechanical strength. In other embodiments of this application, other highly transparent films, such as PTFE and PVC, may also be used.

[0037] In one specific embodiment of this application, the phase change material nanoparticles in the phase change composite layer are W-doped vanadium dioxide with a nanoparticle size of 50-150 nm. This allows for a phase change temperature close to room temperature (40°C), effectively regulating infrared radiation at a comfortable temperature for the human body, reducing near-infrared transmission at high temperatures and increasing it at low temperatures. The resin material is TPU, composited with the phase change nanoparticles to form a film. This maximizes the regulation of infrared radiation characteristics while exhibiting excellent elasticity, flexibility, tear resistance, and weather resistance, significantly improving the mechanical properties of the film and serving as an adhesive layer to prevent tearing and delamination. The thickness of the phase change composite layer is typically 10-100 μm. Furthermore, the phase change material nanoparticles can also be any one or a mixture of several of VO2, W-VO2, WO3, SiO2, Co3O4, TiO2, and Al2O3 nanoparticles, and the resin material can also be any one or a mixture of several of PE, ETFE, PVC, and EVA.

[0038] In one specific embodiment of this application, both the first transparent layer and the second transparent layer are formed by a cross-grid structure of silver nanowires, with a thickness of typically 10-100 nm. This can reduce the contact resistance between silver nanowires and localized hot spots during film use while ensuring high light transmittance, thereby increasing the electrical, thermal and mechanical stability of the transparent electrode and ensuring its performance during the stretching and bending processes of the film.

[0039] The photoelectric layer in this application can effectively collect and capture ultraviolet and infrared light, as well as some visible light, and convert it into electrical energy efficiently. At the same time, it allows most of the visible light and some of the infrared light to pass through, ensuring efficient power generation while maximizing the transmission of visible light.

[0040] In one specific embodiment of this application, the transparent encapsulation protective layer uses ETFE film to encapsulate and protect the surface. It offers advantages such as lightweight, high light transmittance, self-cleaning, flexibility, corrosion resistance, impact resistance, and heat resistance. Especially when combined with an ETFE film substrate, it is even more suitable for membrane structure architecture. The transparent encapsulation protective layer can also be made of one or a mixture of TPU, PE, PVC, and EVA.

[0041] Example

[0042] Table 1 Examples 1-7 and Comparative Examples

[0043]

[0044]

[0045] The specific embodiments described above illustrate the specific performance of different structures of the intelligent thermal control semi-transparent energy-saving membrane for buildings provided by this invention. Specific parameter settings are shown in Table 1. The membrane structures of Examples 1-6 can effectively regulate the absorption, reflection, and transmission of infrared solar energy. They can control the infrared light to prevent it from entering the building when the temperature reaches approximately 40-50°C, thus reducing heat accumulation and enabling intelligent control of the building's indoor temperature. This helps reduce the energy consumption required to achieve a comfortable living temperature within the building. Examples 7 and the comparative examples do not have this function. Furthermore, different thicknesses and ratios in Examples 1-7 can adjust the visible light transmittance and power generation efficiency of the resulting membrane structure, jointly achieving full utilization of sunlight while saving energy. In addition, the cross-grid structure of silver nanowires can effectively increase the electrical, thermal, and mechanical stability of the membrane structure, ensuring performance during stretching and bending processes. Compared to using a membrane structure, the cross-grid structure of silver nanowires is more beneficial to the optical transmittance and bending resistance of the final membrane structure, avoiding localized hot spots and ensuring durability while maintaining high transmittance. Compared to Example 1, when a silver film of the same thickness is prepared by spin coating or vapor deposition to replace the silver nanowire cross-network structure, and all other parameters are the same as in Example 1, its bending resistance is significantly reduced. Table 2 compares the characteristics of commonly used photovoltaic power generation units. The photoelectric layer in this invention adopts an organic photovoltaic photoelectric layer, especially a stacked structure of PEDOT:PSS, organic hybrid thin film, and AZO, wherein the organic hybrid thin film is a mixture of PM6 and Y6. Organic photovoltaic cells have the advantages of flexibility and high transmittance. This invention realizes the preparation of a semi-transparent energy-saving film with intelligent thermal control for building applications.

[0046] Table 2: Comparison of Commonly Used Photovoltaic Units with High Capacity

[0047] Solar cells type Flexibility Light transmittance Efficiency Records Silicon solar cells crystal rigidity Opaque 26.81％ Gallium arsenide solar cells crystal rigidity Opaque 27.9％ CZTSSe battery film Flexible Opaque 14.9％ CIGS batteries film Flexible Opaque 23.6％ CdTe batteries film Flexible Opaque 22.3％ Perovskite solar cells New thin film Flexible Semi-transparent 26％ Organic photovoltaic cells New thin film Flexible Light transmission 19.2％

[0048] Specifically, this invention combines multiple materials using a specific structure to design and form an intelligent, thermally controlled, semi-transparent, energy-saving membrane suitable for use in buildings. Its principle is as follows: Figure 7 As shown, it can efficiently utilize solar energy across all wavelengths. While allowing as much visible light (380-760nm) as possible to pass through for lighting, it can also effectively regulate the near-infrared transmittance (1000-2500nm) according to the external temperature to maintain a suitable indoor temperature. Simultaneously, it can effectively collect and capture ultraviolet (300-380nm), some visible (380-760nm), and near-infrared (760-1000nm) sunlight and efficiently convert it into electrical energy. Figure 2 , 3It can be seen that the membrane in this application can effectively regulate the transmittance of infrared light and effectively control near-infrared radiation under different temperature environments. For example, in the high-temperature environment of summer, it can prevent infrared light that accumulates heat from entering the building through the membrane, while in the low-temperature environment of winter, it can allow light containing infrared bands to enter and prevent indoor heat from dissipating, thereby raising the building temperature. Figure 4 Compared to the solution with a phase change composite layer in this application, the solution without a phase change composite layer can more effectively and intelligently regulate the indoor thermal environment and energy consumption when applied to buildings. Furthermore, as... Figure 5 , 6 As shown, both the first transparent layer and the second transparent layer in this application are silver nanowire cross-grid structure layers, which are not only thin and transparent, but also have excellent bending resistance, effectively avoiding problems such as aging and cracking caused by local hot spots.

[0049] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including both the preferred embodiments and all changes and modifications falling within the scope of the invention.

[0050] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A semi-transparent energy generating and saving film for intelligent thermal regulation in buildings, characterized in that, The translucent energy-generating and energy-saving film comprises, from the inside of the building to the outside, a transparent film substrate, a first transparent layer, a photoelectric layer, a second transparent layer, and a transparent packaging protective layer; a phase change composite layer is further arranged between the transparent film substrate and the first transparent layer; the phase change composite layer is a composite of phase change material nanoparticles and resin material, the nanoparticles are W-VO2 nanoparticles with a size of 50-150 nm, the first transparent layer and the second transparent layer are both silver nanowire cross-grid structure layers formed by repeatedly and uniformly coating a silver nanowire dispersion liquid, and the photoelectric layer is a PEDOT:PSS, organic mixed film and AZO laminated structure, and the organic mixed film is a mixture of PM6 and Y6.

2. The intelligent thermal regulating, semi-transparent, energy-generating, energy saving film for buildings of claim 1, wherein, The transparent film substrate is made of one or more of ETFE, PTFE and PVC.

3. The intelligent thermal regulating, semi-transparent, energy-generating, energy saving film for buildings of claim 1, wherein, The phase change composite layer is a mixed film of phase change material nanoparticles and resin material, the mass percentage of the nanoparticles is 1-10 wt%, and the thickness of the phase change composite layer is 10-100 μm.

4. The intelligent thermal regulating, semi-transparent, energy-generating, energy- saving film for buildings of claim 1, wherein, The resin material is one or a mixture of several of TPU, PE, ETFE, PVC and EVA.

5. The intelligent thermal regulating, semi-transparent, energy-generating, energy- saving film of claim 1, wherein, The mass ratio of PM6 to Y6 is 1:n, 1 6. The intelligent thermal regulating, semi-transparent, energy-generating, energy saving film for buildings of claim 1, wherein, The transparent packaging protective layer is a mixture of one or several of TPU, PE, ETFE, PVC and EVA.

7. A method of making a semi-transparent energy-generating and energy-saving film for intelligent thermal regulation of buildings according to any one of claims 1 to 6, characterized in that, The method comprises the following steps: 1) ultrasonic cleaning and ultraviolet ozone treatment of the flat transparent film substrate with water; 2) drying the film obtained in step 1) and spin coating a mixed solution of phase change material nanoparticles and resin material, and drying; 3) layer-by-layer stacking of the film obtained in step 2) by repeatedly spin coating a silver nanowire dispersion liquid at multiple rotation speeds to form a silver nanowire grid structure layer, and annealing at 150℃ for 15 minutes; 4) ultraviolet ozone treatment of the film obtained in step 3), spin coating PEDOT:PSS, and annealing at 110℃ for 15 minutes; 5) spin coating of an organic mixed film containing PM6 and Y6 in an inert gas protective atmosphere, and annealing at 100℃ for 10 minutes; 6) spin coating of an AZO layer on the film obtained in step 5), and annealing at 60℃ for 8 minutes; 7) layer-by-layer stacking of the film obtained in step 6) by repeatedly spin coating a silver nanowire dispersion liquid at multiple rotation speeds to form a silver nanowire grid structure layer, and annealing at 150℃ for 15 minutes; 8) packaging protection of the film obtained in step 7) with a transparent film material.

8. The method of claim 7, wherein the method further comprises the step of: 8.

1. applying a semi-transparent energy generating film on the surface of the building. The solvent in the mixed solution of phase change material nanoparticles and resin material, the solvent for spin coating PEDOT:PSS, the solvent for spin coating AZO, the solvent for spin coating of the organic mixed film, and the solvent for the silver nanowire dispersion liquid are one or a mixture of several of water, ethanol, ethylene glycol, acetone, isopropyl alcohol, DMF, chlorobenzene and chloroform.

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