Energy-saving building structure based on hydrogel and preparation method thereof

Abstract

The application discloses an energy-saving building structure based on a hydrogel and a preparation method thereof, and relates to the field of functional hydrogels. The energy-saving building structure is used for isolating a first space and a second space, the first space has a first ambient temperature, and the second space has a second ambient temperature; the energy-saving building structure comprises a first substrate, a first hydrogel layer, an isolation layer, a second hydrogel layer and a second substrate which are arranged in layers; the first hydrogel layer has a first phase transition temperature and a second phase transition temperature; when the first ambient temperature is below the first phase transition temperature or above the second phase transition temperature, the first hydrogel layer is in a non-transparent state; when the first ambient temperature is between the first phase transition temperature and the second phase transition temperature, the first hydrogel layer is in a transparent state; and when the temperature difference between the first ambient temperature and the second ambient temperature is greater than or equal to a preset threshold, the second hydrogel layer can perform thermoelectric conversion. The energy-saving building structure can realize annual bidirectional heat management and continuous thermoelectric energy conversion.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of functional hydrogel, and particularly to a hydrogel-based energy-saving building structure and a preparation method thereof. BACKGROUND

[0002] At present, building energy consumption accounts for 30-40% of global energy consumption, about half of which is used for heating, ventilation and air conditioning systems (HVAC). Traditional glass windows, as the component with the lowest energy efficiency in building envelope structure, have problems such as heat loss in winter and heat intrusion in summer. Existing energy-saving window technologies such as thermochromic, photochromic and electrochromic can adjust solar radiation flux to a certain extent, but most of them are designed for single function, passive response, or need complex electrical control, and it is difficult to simultaneously achieve high light transmittance, wide temperature range regulation and energy recovery.

[0003] Hydrogel has become a strong candidate material for thermochromic smart windows due to its adjustable refractive index, reversible phase transition and simple preparation. However, traditional single phase change hydrogel can only realize optical modulation near a single critical temperature, which cannot meet the bidirectional thermal management requirements in different seasons. At the same time, existing heat recovery methods mostly rely on photovoltaic (PV) systems, which are limited by sunlight conditions and do not have all-weather working ability. SUMMARY

[0004] In order to solve the above technical problems, the present application aims to provide a hydrogel-based energy-saving building structure and a preparation method thereof. The energy-saving building structure can realize all-year bidirectional thermal management and continuous thermoelectric energy conversion, has high optical transparency, excellent thermal regulation performance and long-term stability, and is suitable for wide deployment in different climate conditions and application scenarios.

[0005] According to a first aspect of the present application, a hydrogel-based energy-saving building structure is provided, which is used to isolate a first space and a second space, the first space has a first ambient temperature, and the second space has a second ambient temperature.

[0006] From the direction of the first space to the second space, the energy-saving building structure comprises a first substrate, a first hydrogel layer, an isolation layer, a second hydrogel layer and a second substrate which are stacked.

[0007] The first hydrogel layer has a first phase transition temperature and a second phase transition temperature, when the first ambient temperature is below the first phase transition temperature or above the second phase transition temperature, the first hydrogel layer is in a non-transparent state; when the first ambient temperature is between the first phase transition temperature and the second phase transition temperature, the first hydrogel layer is in a transparent state.

[0008] The second hydrogel layer is capable of thermoelectric conversion when a temperature difference between the first ambient temperature and the second ambient temperature is greater than or equal to a preset threshold.

[0009] In some embodiments of the application, the first hydrogel layer is formed from a first hydrogel material comprising components at the following concentrations:

[0010] a low molecular weight ionic surfactant 4.45-10.00 % w / v;

[0011] a heat-sensitive polymer 1.0-9.0 % w / v.

[0012] In some embodiments of the application, the low molecular weight ionic surfactant comprises 1-hexadecyl-3-methylimidazolium salicylate; and / or

[0013] the heat-sensitive polymer comprises poly(N-isopropylacrylamide).

[0014] In some embodiments of the application, the second hydrogel layer is formed from a second hydrogel material comprising components at the following concentrations:

[0015] a hydrogel matrix 32.5-49.0 wt%;

[0016] a redox ion pair 0.21-0.46 mol / L.

[0017] In some embodiments of the application, the hydrogel matrix comprises a triblock copolymer of polyoxyethylene-polyoxypropylene-polyoxyethylene; and / or

[0018] the redox ion pair comprises one or more of Fe(CN)6 3- / Fe(CN)6 4- , K3[Co(CN)6] / K4[Co(CN)6], [Ru(NH3)6] 3+ / [Ru(NH3)6] 2+ .

[0019] In some embodiments of the application, the second hydrogel material further comprises components at the following concentrations:

[0020] a strong chaotropic additive 0.5-1.4 mol / L.

[0021] In some embodiments of the application, the strong chaotropic additive comprises one or more of guanidine hydrochloride, guanidine nitrate, guanidine carbonate, lithium chloride, zinc chloride, magnesium chloride.

[0022] In some embodiments of the present application, the isolation layer is a transparent heat-conducting film, the transparent heat-conducting film has a light transmittance greater than or equal to 90%, and a thermal conductivity of 1-5 W·m -1 ·K -1 .

[0023] In some embodiments of the present application, the first hydrogel layer has a thickness of 1.0-5.0 mm;

[0024] The second hydrogel layer has a thickness of 1.0-5.0 mm;

[0025] The isolation layer has a thickness of 1.0-5.0 mm.

[0026] According to a second aspect of the present application, a preparation method of a hydrogel-based energy-saving building structure is provided, the preparation method is used for preparing the hydrogel-based energy-saving building structure as any one of the above, and the preparation method comprises:

[0027] The isolation layer is arranged in a pouring mold, so that the isolation layer divides the pouring mold into a first pouring area and a second pouring area;

[0028] A first hydrogel material is poured into the first pouring area to form the first hydrogel layer;

[0029] A second hydrogel material is poured into the second pouring area to form the second hydrogel layer;

[0030] The first substrate is installed on a side of the first hydrogel layer away from the isolation layer;

[0031] The second substrate is installed on a side of the second hydrogel layer away from the isolation layer to form the energy-saving building structure.

[0032] The technical solution provided by the present application can include the following beneficial effects:

[0033] The energy-saving building structure of the present application realizes annual bidirectional heat management and continuous thermoelectric energy conversion through the physical coupling integration of the first hydrogel layer with double-threshold heat response phase change and the second hydrogel layer of the thermoelectric chemical cell, has high optical transparency, excellent heat regulation performance and long-term stability, and is suitable for being widely deployed in different climate conditions and application scenarios.

[0034] It should be understood that the above general description and the following detailed description are only exemplary and explanatory, and cannot limit the present application. BRIEF DESCRIPTION OF DRAWINGS

[0035] The accompanying drawings incorporated in and forming a part of the specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the application.

[0036] Figure 1 is a schematic diagram of a layer structure of an energy-saving building structure according to an exemplary embodiment.

[0037] Figure 2 is a C 16 Variation of optical transmittance of MeImSal, pNIPAm and the first hydrogel layer (DTRPCH) at low, intermediate and high temperatures.

[0038] Figure 3 is a C 16 Differential scanning calorimetry (DSC) curves of MeImSal, pNIPAm and DTRPCH.

[0039] Figure 4 is a photograph of the appearance of deionized water at 10°C, 25°C and 40°C according to an exemplary embodiment.

[0040] Figure 5 is a C 16 Photographs of the appearance of MeImSal at 10°C, 25°C and 40°C.

[0041] Figure 6 is a photograph of the appearance of pNIPAm at 10°C, 25°C and 40°C according to an exemplary embodiment.

[0042] Figure 7 is a photograph of the appearance of DTRPCH at 10°C, 25°C and 40°C according to an exemplary embodiment.

[0043] Figure 8 is a graph of the luminance transmittance cycling performance of DTRPCH (transparent and non-transparent states) at different ambient temperatures according to an exemplary embodiment.

[0044] Figure 9 is a non-isothermal cell potential graph of the second hydrogel layer according to an exemplary embodiment.

[0045] Figure 10 is a thermal cell discharge graph of the second hydrogel layer according to an exemplary embodiment.

[0046] Figure 11 is an initial appearance picture of a flower not obscured by the first hydrogel layer according to an exemplary embodiment.

[0047] Figure 12 is an appearance picture of a flower obscured by the first hydrogel layer of different thicknesses at 10°C according to an exemplary embodiment.

[0048] Figure 13 Picture showing the appearance of flowers blocked by the first hydrogel layer with different thicknesses at 25℃ according to an exemplary embodiment.

[0049] Figure 14 Picture showing the appearance of flowers blocked by the first hydrogel layer with different thicknesses at 40℃ according to an exemplary embodiment.

[0050] Figure 15 Flow chart showing a preparation method of a hydrogel-based energy-saving building structure according to an exemplary embodiment.

[0051] Figure 16 Picture showing the indoor and outdoor temperature change curves of the energy-saving building structure of Example 1 in different seasons.

[0052] Figure 17 Picture showing the output voltage of the energy-saving building structure of Example 1 under the simulation condition of diurnal temperature difference.

[0053] Reference signs:

[0054] 1, first substrate; 2, first hydrogel layer; 3, isolation layer; 4, second hydrogel layer; 5, second substrate; 6, encapsulation layer;

[0055] 10, first space; 20, second space. DETAILED DESCRIPTION

[0056] In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions of the present application will be described clearly and completely below with reference to the embodiments of the present application and the drawings. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application. It should be noted that, in the case of no conflict, the embodiments in the present application and the features in the embodiments can be combined with each other at will.

[0057] The application provides an energy-saving building structure based on hydrogel, which is used for isolating a first space and a second space, the first space has a first ambient temperature, and the second space has a second ambient temperature; from the direction of the first space to the second space, the energy-saving building structure comprises a first substrate, a first hydrogel layer, an isolation layer, a second hydrogel layer and a second substrate which are arranged in layers; the first hydrogel layer has a first phase transition temperature and a second phase transition temperature, when the first ambient temperature is below the first phase transition temperature or above the second phase transition temperature, the first hydrogel layer is in a non-transparent state; when the first ambient temperature is between the first phase transition temperature and the second phase transition temperature, the first hydrogel layer is in a transparent state; when the temperature difference between the first ambient temperature and the second ambient temperature is greater than or equal to a preset threshold, the second hydrogel layer can perform thermoelectric conversion. The energy-saving building structure of the application realizes annual two-way heat management and continuous thermoelectric energy conversion by integrating the first hydrogel layer with a double-threshold heat response phase change and the second hydrogel layer with a thermoelectric chemical cell, has high optical transparency, excellent heat regulation performance and long-term stability, and is suitable for being widely deployed in different climate conditions and application scenarios.

[0058] Some specific embodiments described below are intended to facilitate the understanding of the present embodiment by those skilled in the art, and the present embodiment is not limited to some specific embodiments described below.

[0059] As shown in Figure 1 An example embodiment of the application provides an energy-saving building structure based on hydrogel, which is used for isolating a first space 10 and a second space 20, the first space 10 has a first ambient temperature, and the second space 20 has a second ambient temperature; from the direction of the first space 10 to the second space 20, the energy-saving building structure comprises a first substrate 1, a first hydrogel layer 2, an isolation layer 3, a second hydrogel layer 4 and a second substrate 5 which are arranged in layers; the first hydrogel layer 2 has a first phase transition temperature and a second phase transition temperature, when the first ambient temperature is below the first phase transition temperature or above the second phase transition temperature, the first hydrogel layer 2 is in a non-transparent state; when the first ambient temperature is between the first phase transition temperature and the second phase transition temperature, the first hydrogel layer 2 is in a transparent state; when the temperature difference between the first ambient temperature and the second ambient temperature is greater than or equal to a preset threshold, the second hydrogel layer 4 can perform thermoelectric conversion.

[0060] In this embodiment, the energy-saving building structure can be used for building curtain walls, transportation tool windows, and other transparent heat insulation systems, for example, the energy-saving building structure can be used for building glass, vehicle sunroofs, greenhouse glass, and other scenarios. When the energy-saving building structure is used as a building curtain wall, the first space 10 can be an outdoor space, the second space 20 can be an indoor space, the first ambient temperature can be an outdoor temperature, and the second ambient temperature can be an indoor temperature. The first hydrogel layer 2 is arranged close to the outdoor environment, and the second hydrogel layer 4 is arranged close to the indoor environment.

[0061] The first hydrogel layer 2 (DTRPCH) has the characteristics of a double-threshold heat response phase change, that is, it has two reversible phase change points, a first phase change temperature and a second phase change temperature. When the first ambient temperature is below the first phase change temperature or above the second phase change temperature, the first hydrogel layer 2 is in a non-transparent state. When the first ambient temperature is between the first phase change temperature and the second phase change temperature, the first hydrogel layer 2 is in a transparent state. The first phase change temperature can be 14-20 ℃, and the second phase change temperature can be 28-36 ℃. That is, when the outdoor temperature is below the first phase change temperature, for example in winter, the first hydrogel layer 2 can be in a non-transparent state to efficiently scatter visible light and near-infrared light, providing heat insulation for the indoor environment. When the outdoor temperature is above the second phase change temperature, for example in summer, the first hydrogel layer 2 can also be in a non-transparent state, effectively blocking solar heat radiation to reduce the increase in indoor temperature. When the first ambient temperature is between the first phase change temperature and the second phase change temperature, for example in spring and autumn, the first hydrogel layer 2 maintains a matching refractive index state and is in a transparent state, achieving a visible light transmittance of 90%. Through the double-temperature response phase change characteristics of the first hydrogel layer 2 of the present application, the needs for heat insulation in summer and heat preservation in winter can be met.

[0062] It should be noted that "below the first phase change temperature or above the second phase change temperature" in the present application includes the number itself, that is, "below the first phase change temperature" includes the first phase change temperature and temperatures less than the first phase change temperature, and "above the second phase change temperature" includes the second phase change temperature and temperatures greater than the second phase change temperature; "between the first phase change temperature and the second phase change temperature" does not include the number itself, that is, "between the first phase change temperature and the second phase change temperature" includes temperatures greater than the first phase change temperature and less than the second phase change temperature. For example, when the first phase change temperature is 16 ℃ and the second phase change temperature is 32 ℃, the first hydrogel layer 2 is in a non-transparent state when the first ambient temperature is ≤16 ℃ or ≥32 ℃; the first hydrogel layer 2 is in a transparent state when 16 ℃ < first ambient temperature < 32 ℃.

[0063] The second hydrogel layer 4 (F127TEC) can be used as a thermoelectric chemical cell, which can perform thermoelectric conversion. The temperature difference between the first and second ambient temperatures (i.e., the indoor and outdoor temperature difference) can drive ion migration and electrode reactions to achieve thermoelectric conversion. The preset threshold value ΔT can be, for example, 10 K. The output power density of the second hydrogel layer 4 under the condition of ΔT = 10 K is 0-5 W·m -2 , and the thermoelectric conversion efficiency is 0-0.2%. It has good stability and can continuously output electrical energy under day and night and cloudy conditions. This energy collection method can be an effective supplement to photovoltaic systems, especially suitable for cloudy, cold, or night environments. In addition, as a hydrogel material, the second hydrogel layer 4 also has the advantages of flexibility, transparency, and large-area preparation, and can work cooperatively with the first hydrogel layer 2 without affecting its optical performance.

[0064] The isolation layer 3 is located between the first hydrogel layer 2 and the second hydrogel layer 4, which can isolate the first hydrogel layer 2 and the second hydrogel layer 4 to avoid functional failure of the first hydrogel layer 2 and the second hydrogel layer 4.

[0065] The first substrate 1 and the second substrate 5 are respectively arranged on the outer side of the first hydrogel layer 2 and the second hydrogel layer 4, which can protect the first hydrogel layer 2 and the second hydrogel layer 4 to ensure the structural integrity and long-term stability of the energy-saving building structure, and effectively prevent water evaporation and ion leakage of the first hydrogel layer 2 and the second hydrogel layer 4. The first substrate 1 and the second substrate 5 can be made of transparent materials to maintain optical transparency. The first substrate 1 and the second substrate 5 can be made of the same material or different materials, for example, the first substrate 1 and the second substrate 5 can be made of indium tin oxide glass (ITO), fluorine-doped tin oxide glass (FTO), aluminum-doped zinc oxide glass (AZO), antimony-doped tin oxide glass (ATO), etc.

[0066] The energy-saving building structure can further include an encapsulation layer 6 for encapsulating the first substrate 1, the first hydrogel layer 2, the isolation layer 3, the second hydrogel layer 4, and the second substrate 5 to support and fix, seal and protect, etc.

[0067] The energy-saving building structure of the present application is integrated by physical coupling of the first hydrogel layer 2 with a double-threshold thermal response and the second hydrogel layer 4 of the thermoelectric chemical cell, realizing annual two-way thermal management and continuous thermoelectric energy conversion, with high optical transparency, excellent thermal regulation performance and long-term stability, suitable for wide deployment in different climate conditions and application scenarios.

[0068] In an exemplary embodiment, the first hydrogel layer 2 is formed of a first hydrogel material, which includes the following concentrations of components:

[0069] Low molecular weight ionic surfactant 4.45-10.00 %w / v;

[0070] Thermosensitive polymer 1.0-9.0 %w / v.

[0071] In this embodiment, the first hydrogel layer 2 is formed of a first hydrogel material, which includes a low molecular weight ionic surfactant and a thermosensitive polymer. The low molecular weight ionic surfactant mainly refers to a compound with relatively small molecular weight, which can quickly migrate in aqueous solution and promote the formation of hydrogel. The molecular weight of the low molecular weight ionic surfactant may, for example, be 100-2000 g / mol. If the molecular weight is too low, the molecular structure is too simple, and it is difficult to form stable micelles or networks, making it difficult to achieve effective gelation. If the molecular weight is too high, the self-assembly efficiency may be reduced, affecting the thermal responsiveness and transparency of the hydrogel. Therefore, when the molecular weight of the low molecular weight ionic surfactant is 100-2000 g / mol, it can ensure that it promotes the self-assembly of the hydrogel while maintaining good optical and thermal response performance.

[0072] The thermosensitive polymer refers to a high molecular material whose structure or physicochemical properties change significantly when the external temperature changes. In this embodiment, the low molecular weight ionic surfactant and the thermosensitive polymer have different phase transition temperatures, and mixing them does not affect each other's phase transition temperature. The low molecular weight ionic surfactant has the characteristics of amphiphilic molecules with hydrophobic / hydrophilic balance, and it has π-π stacking ability.

[0073] At low temperatures, for example, when the first environmental temperature is below the first phase transition temperature, a dense lamellar structure (lamellar aggregate) can be formed, which strongly scatters light, causing the first hydrogel layer 2 to be in a non-transparent state. When the first environmental temperature is higher than the first phase transition temperature, the aggregate changes to a fiber / vermicular structure, significantly reducing light scattering, and the first hydrogel layer 2 returns to a transparent state.

[0074] At high temperature, for example, when the first ambient temperature is above the second phase transition temperature, the heat-sensitive polymer dehydrates and shrinks, forming a multi-scale scattering structure, effectively blocking solar heat radiation. The solar energy modulation capacity at low and high temperature states is more than 80%.

[0075] In the intermediate temperature range, for example, when the first ambient temperature is between the first phase transition temperature and the second phase transition temperature, neither the low molecular weight ionic surfactant nor the heat-sensitive polymer undergoes thermal scattering, both of which remain in a matched refractive index state in the intermediate temperature range. Therefore, the first hydrogel layer 2 can exhibit high light transmittance, thereby achieving a visible light transmittance of > 90%.

[0076] In this embodiment, the first hydrogel layer 2 has good long-term stability and environmental adaptability, and the performance of the first hydrogel layer 2 does not significantly decay in 100 heating-cooling cycles at -5°C to 40°C, and has excellent anti-icing ability (remains transparent when super-cooled to -5°C).

[0077] The amount of low molecular weight ionic surfactant and heat-sensitive polymer also affects the high light transmittance of the first hydrogel layer 2. Therefore, in this embodiment, the concentration of low molecular weight ionic surfactant and heat-sensitive polymer in the first hydrogel material is controlled to control the visible light transmittance of the first hydrogel layer 2 in the intermediate temperature range, and to achieve the best light transmittance and modulation performance.

[0078] For example, the concentration of low molecular weight ionic surfactant in the first hydrogel material can be 4.45 %w / v, 5.89 %w / v, 6.44 %w / v, 7.45 %w / v, 8.28 %w / v, 10.00 %w / v. The concentration of low molecular weight ionic surfactant in the first hydrogel material can also be any value between the example concentration values, for example, the concentration of low molecular weight ionic surfactant in the first hydrogel material can also be any value between 5.89-7.45 %w / v.

[0079] The concentration of heat-sensitive polymer in the first hydrogel material can be 1.0 %w / v, 3.7 %w / v, 5.3 %w / v, 6.9 %w / v, 8.8 %w / v, 9.0 %w / v. The concentration of heat-sensitive polymer in the first hydrogel material can also be any value between the example concentration values, for example, the concentration of heat-sensitive polymer in the first hydrogel material can also be any value between 3.7-5.3 %w / v.

[0080] The components of the first hydrogel material further include deionized water. The first hydrogel material can be prepared by the following method: dissolving the low-molecular-weight ionic surfactant and the thermosensitive polymer in deionized water to obtain a mixture; and subjecting the mixture to ultrasonic treatment for 20-40 min to obtain a uniform first hydrogel material.

[0081] The energy-saving building structure of the present application has excellent temperature regulation performance: under high-temperature conditions in summer, the first hydrogel layer 2 effectively prevents solar radiation from entering the room by phase change scattering and absorption, reducing the rate of temperature rise; the second hydrogel layer 4 further converts part of the heat accumulated on the outer layer into electrical energy, reducing heat conduction to the room, achieving more efficient cooling. In summer night, the second hydrogel layer 4 accelerates the dissipation of indoor residual heat through thermoelectric conversion and heat radiation, enhancing the self-cooling capacity. Under low-temperature conditions in winter, the first hydrogel layer 2 effectively inhibits the loss of indoor heat by reflecting heat radiation; the second hydrogel layer 4 can recover part of the heat diffusion energy, achieving the combination of passive insulation and active energy collection.

[0082] The energy-saving building structure of the present application also has excellent energy collection and utilization capacity: the second hydrogel layer 4 stably outputs voltage and current under temperature difference, which can drive small energy storage units such as capacitors. When the energy-saving building structure is used as a building curtain wall, it can generate considerable voltage and power output for a single window (0.01 m²) under typical temperature difference, and multiple windows in series can meet the needs of low-power consumption devices such as indoor sensors and automation systems; although the thermoelectric efficiency of the single unit is low, it has a significant synergistic effect in reducing heat diffusion and providing long-term energy buffering.

[0083] In an exemplary embodiment, the low-molecular-weight ionic surfactant includes 1-hexadecyl-3-methylimidazolium salicylate.

[0084] In this embodiment, the low-molecular-weight ionic surfactant includes 1-hexadecyl-3-methylimidazolium salicylate (English name: 1-hexadecyl-3-methylimidazolium salicylate ， C 16 MeImSal), at low temperatures, for example, the first ambient temperature ≤ 16 ℃, C 16 The hydrophobic chain and imidazole-benzoic acid group of MeImSal can drive the formation of lamellar aggregates, which can form a dense lamellar structure (lamellar aggregate), strongly scatter heat and light, resulting in a non-transparent state of the first hydrogel layer 2. When the first ambient temperature > 16 ℃, the aggregate changes to a fiber / vermicular structure, significantly reducing light scattering, and the first hydrogel layer 2 returns to a transparent state.

[0085] In an exemplary embodiment, the thermosensitive polymer includes poly(N-isopropylacrylamide).

[0086] In this embodiment, the heat-sensitive polymer can be poly(N-isopropylacrylamide) (pNIPAm). At high temperatures, for example, when the first ambient temperature is ≥ 32 ℃, the pNIPAm network undergoes dehydration and shrinkage, forming a multi-scale scattering structure, which effectively blocks solar heat radiation.

[0087] To more clearly illustrate the effect of the first hydrogel layer 2, as shown in Figure 2 , 1-hexadecyl-3-methyl imidazolium salicylate (C 16 MeImSal), poly(N-isopropylacrylamide) (pNIPAm), and the first hydrogel layer 2 (DTRPCH) formed by C 16 MeImSal and pNIPAm were tested at low temperatures (≤ 16 ℃), intermediate temperatures (16-32 ℃), and high temperatures (≥ 32 ℃) to observe changes in optical transmittance. Figure 2 The abscissa represents wavelength (nm), and the ordinate represents light transmittance (%); Figure 2 In the figure, curve A represents C 16 MeImSal (25 ℃), curve B represents DTRPCH (25 ℃), curve C represents pNIPAm (25 ℃), curve D represents DTRPCH (10 ℃), curve E represents C 16 MeImSal (10 ℃), curve F represents DTRPCH (40 ℃), and curve G represents pNIPAm (40 ℃); Figure 2 In the figure, white area I represents a transparent state of the material, and blue area II represents a non-transparent state of the material. According to Figure 2 It can be seen that the first hydrogel layer 2 (DTRPCH) is in a non-transparent state at low temperatures, has high light transmittance at intermediate temperatures, and is again in a non-transparent state at high temperatures.

[0088] As shown in Figure 3 , in the figure, Figure 3 the abscissa represents temperature (℃), and the ordinate represents heat flow; area III represents a non-transparent state of the material; area IV represents a transparent state of the material; area V represents a non-transparent state of the material; line H represents DTRPCH; line I represents C 16 MeImSal; line J represents pNIPAm; τ c1 represents the low-temperature phase transition temperature range, and τ c2 represents the high-temperature phase transition temperature range. According to Figure 3 It can be seen that C 16 MeImSal has a low-temperature phase transition temperature, pNIPAm has a high-temperature phase transition temperature, and DTRPCH has both a low-temperature phase transition temperature and a high-temperature phase transition temperature.

[0089] Figures 4-7 It shows deionized water, C 16 A comparison of the appearance of MeImSal, pNIPAm, and DTRPCH at 10℃, 25℃, and 40℃ visually demonstrates their light transmittance at different temperatures.

[0090] Figure 4 The images, from top to bottom, show the appearance of deionized water at 10℃, 25℃, and 40℃. The dashed boxes indicate the areas containing the deionized water. Figure 4 It can be seen that the light transmittance of deionized water is the same at different temperatures.

[0091] Figure 5 The middle section is C from top to bottom. 16 MeImSal's appearance at 10℃, 25℃, and 40℃, respectively. The dashed box indicates C. 16 The region where MeImSal is located, according to Figure 5 It can be seen that C 16 MeImSal is opaque at low temperatures.

[0092] Figure 6 The images, from top to bottom, show the appearance of pNIPAm at 10℃, 25℃, and 40℃. The dashed boxes indicate the areas containing pNIPAm. Figure 6 It can be seen that pNIPAm is opaque at high temperatures.

[0093] Figure 7 The images, from top to bottom, show the appearance of the DTRPCH at 10℃, 25℃, and 40℃. The dashed box indicates the area where the DTRPCH is located. Figure 7 It can be seen that DTRPCH is opaque at both low and high temperatures.

[0094] like Figure 8 As shown, Figure 8 In the diagram, the horizontal axis represents the number of cycles, and the vertical axis represents the luminance transmittance Γ. IUM (%) Figure 8 In the diagram, black squares represent 10℃, red circles represent 25℃, and blue triangles represent 40℃. Figure 8 In this study, DTRPCH is opaque at 10°C and 40°C, and transparent at 25°C; according to... Figure 8 It can be seen that DTRPCH still exhibits dual-temperature response characteristics when the ambient temperature changes, indicating that the material has long-term stability. The optical regulation cycle efficiency of the energy-saving building structure of this application exceeds 90%, and the volume retention rate after 180 days after glass encapsulation is greater than 97%, demonstrating long-term durability.

[0095] In an exemplary embodiment, the second hydrogel layer 4 is formed of a second hydrogel material comprising components at the following concentrations:

[0096] Hydrogel matrix 32.5-49.0 wt%;

[0097] Redox ion pair 0.21-0.46 mol / L.

[0098] Currently, the energy recovery of energy-saving building structures relies mainly on photovoltaic systems. However, photovoltaic power generation is limited by sunlight conditions and cannot work stably at night, on cloudy days, or in weak light environments. Therefore, photovoltaic systems are mainly suitable for energy recovery under direct sunlight conditions, but their limitation is that they do not have all-weather and continuous operation capabilities. In this embodiment, the second hydrogel layer 4 is based on the reversible redox reaction of redox ion pairs. Under the temperature difference between the first and second ambient temperatures, reduction of redox ion pairs occurs at the cold end, oxidation of redox ion pairs occurs at the hot end, electrons flow in the external circuit, and ions migrate in the hydrogel matrix, completing the thermoelectric chemical cycle and realizing electric energy output to achieve thermoelectric conversion.

[0099] The main effects of the second hydrogel layer 4 include:

[0100] ① Functional complementation: The second hydrogel layer 4 can achieve a power density of 0.05-2 W·m -2 under a temperature difference of 10K, which can actively perform thermoelectric conversion when there is a temperature difference indoors and outdoors, continuously output electric energy, and thus compensate for the deficiencies of photovoltaic systems at night or in weak light conditions, continuously outputting electric energy during the day and night and on cloudy days. This energy collection method can serve as an effective supplement to photovoltaic systems and is particularly suitable for cloudy, cold, or night environments.

[0101] ② No interference with optical performance: Due to the use of physical decoupling structure, the second hydrogel layer 4 is isolated from the first hydrogel layer 2 by the isolation layer 3, so that the second hydrogel layer 4 does not affect the light transmission and thermochromic properties of the first hydrogel layer 2, allowing independent optimization of optical regulation and thermoelectric energy collection.

[0102] ③ Synergistic energy saving: The second hydrogel layer 4 partially recovers the heat flow generated by the temperature difference, reducing the direct transfer of heat into the room, which helps to synergize with the optical regulation of the first hydrogel layer 2 to achieve energy-saving effects.

[0103] In addition, the second hydrogel layer 4 of this embodiment has good long-term stability and environmental adaptability, with no significant liquid leakage or performance degradation during long-term operation, ensuring the reliability of the system under various weather conditions.

[0104] The concentration of the hydrogel matrix and the redox ion pair has a great influence on the performance of the second hydrogel layer 4. Within a certain range, as the concentration of the redox ion pair increases, the conductivity of the second hydrogel layer 4 rises, and the thermoelectric potential can reach a peak value (4.96 mV / K); however, when the concentration of the redox ion pair is too high, it will cause crystallization or mixed species, reducing the performance of the second hydrogel layer 4. When the concentration of the hydrogel matrix is too low, the hydrogel matrix is not enough to maintain a transparent gel state, which will also affect the performance of the second hydrogel layer 4. Therefore, in order to balance the conductivity, thermoelectric potential and optical transparency, the concentration of the hydrogel matrix and the redox ion pair in the second hydrogel material needs to be controlled within the above range.

[0105] For example, the concentration of the hydrogel matrix in the second hydrogel material can be 32.5wt%, 38.5wt%, 42.3wt%, 45.3wt%, 49.0wt%. The concentration of the hydrogel matrix in the second hydrogel material can also be any value between the example concentration values, for example, the concentration of the hydrogel matrix in the second hydrogel material can also be any value between 38.5wt% and 45.3wt%.

[0106] The concentration of the redox ion pair in the second hydrogel material can be 0.21 mol / L, 0.26 mol / L, 0.30 mol / L, 0.36 mol / L, 0.46 mol / L. The concentration of the redox ion pair in the second hydrogel material can also be any value between the example concentration values, for example, the concentration of the redox ion pair in the second hydrogel material can also be any value between 0.26 mol / L and 0.36 mol / L.

[0107] In an example embodiment, the hydrogel matrix includes a triblock copolymer of polyoxyethylene-polyoxypropylene-polyoxyethylene.

[0108] In this embodiment, the hydrogel matrix can use a triblock copolymer of polyoxyethylene (PEO)-polyoxypropylene (PPO)-polyoxyethylene (PEO) (Pluronic F127), which has the advantages of low freezing point (-22 ℃), adjustable gelation temperature and high transparency, and can ensure ion transmission.

[0109] In an example embodiment, the redox ion pair includes one or more of Fe(CN)6 3- / Fe(CN)6 4- , K3[Co(CN)6] / K4[Co(CN)6], [Ru(NH3)6] 3+ / [Ru(NH3)6] 2+ .

[0110] In this embodiment, the redox ion pair can be selected as colorless or light-colored redox ion pair to meet aesthetic or performance requirements. For example, Fe(CN)6... 3- / Fe(CN)6 4- Taking the second hydrogel layer 4 as an example, the mechanism of action will be explained: Figure 9 As shown, driven by the temperature difference between the first and second ambient temperatures, for example, ΔT = 10K, Fe(CN)6 occurs at the cold end (blue area). 3- → Fe(CN)6 4- The reduction occurs at the hot end (red area) where Fe(CN)6 is formed. 4- → Fe(CN)6 3- Oxidation; such as Figure 10 As shown, Fe(CN)6 3- / Fe(CN)6 4- After the redox reaction occurs, electrons flow in the external circuit and ions migrate in the hydrogel matrix, completing the thermoelectrochemical cycle and realizing electrical energy output to achieve thermoelectric conversion.

[0111] In one exemplary embodiment, the second hydrogel material further includes components at the following concentrations:

[0112] Strongly ionizable additives: 0.5-1.4 mol / L.

[0113] In this embodiment, the strong liquid-dissociating additive, as a functional additive in the second hydrogel material, can adjust the solvation and crystallization behavior of redox ion pairs to improve the thermoelectric properties of the second hydrogel layer 4.

[0114] The second hydrogel material can be prepared by the following method: dissolving the hydrogel matrix in deionized water, adding redox ion pairs, and stirring at 0°C until a homogeneous solution is obtained. Stirring and dissolving under near-0°C ice-water bath conditions ensures complete dissolution of the redox ion pairs and the highly ionizable additives, maintaining the homogeneity of the solution.

[0115] After being stirred evenly, the second hydrogel material was transferred from a low temperature to a room temperature of 20°C to allow the hydrogel matrix to gel, thereby obtaining a stable second hydrogel layer.

[0116] In one exemplary embodiment, the strong ionizing additive includes one or more of guanidine hydrochloride, guanidine nitrate, guanidine carbonate, lithium chloride, zinc chloride, and magnesium chloride.

[0117] Guanidinium chloride (GdmCl), Guanidine Nitrate, Guanidine Carbonate, Lithium Chloride, Zinc Chloride, Magnesium Chloride have the characteristics of strong ion liquid, which can be used as the strong ion liquid additive of the embodiment.

[0118] Exemplarily, the redox ion pair is Fe(CN)6 3- / Fe(CN)6 4- For example, the strong ion liquid additive takes guanidinium chloride (GdmCl) as an example, and the mechanism of the strong ion liquid additive is explained: Gdm + Cations can selectively bind Fe(CN)6 4- , increase the entropy difference between the oxidation and reduction states, and thus significantly improve the Seebeck coefficient and thermoelectric conversion efficiency.

[0119] Among them, the concentration of the strong ion liquid additive has a significant effect on the thermoelectric properties of the second hydrogel layer 4. For example, under the condition of 0.1 mol / L Fe(CN)6 3- / Fe(CN)6 4- , the Seebeck coefficient without adding GdmCl is about 1.46 mV / K; when the concentration of GdmCl increases to 1 mol / L, the Seebeck coefficient can be increased to 4.24 mV / K; however, when the concentration of GdmCl continues to increase, although it promotes, it will subsequently decrease due to the inhibition of ion migration. Therefore, in the embodiment, the concentration of the strong ion liquid additive is controlled at 0.5-1.4 mol / L, which can effectively improve the thermoelectric properties of the second hydrogel layer 4.

[0120] Exemplarily, the concentration of the strong ion liquid additive in the second hydrogel material can be 0.5 mol / L, 0.8 mol / L, 1.0 mol / L, 1.2 mol / L, 1.4 mol / L. The concentration of the strong ion liquid additive in the second hydrogel material can also be any value between the exemplary concentration values, for example, the concentration of the strong ion liquid additive in the second hydrogel material can also be any value between 0.8-1.2 mol / L.

[0121] In an exemplary embodiment, the isolation layer 3 is a transparent heat-conducting film, and the transmittance of the transparent heat-conducting film is greater than or equal to 90%, and the thermal conductivity is 1-5 W·m -1 ·K -1 .

[0122] It is found that the redox ion pair directly incorporated into the first hydrogel material generates yellow flocculation, which destroys the phase change performance of the first hydrogel layer 2. Therefore, the present application adopts a physically decoupled double-layer architecture, which can play a physical barrier role by setting a separation layer 3 between the first hydrogel layer 2 and the second hydrogel layer 4, avoiding the contact between the redox ion pair in the second hydrogel layer 4 and the first hydrogel layer 2, effectively blocking ion penetration, and preventing chemical failure. The separation layer 3 adopts a transparent heat-conducting film, and its light transmittance is greater than or equal to 90%, which can maintain good interface optical transparency; the thermal conductivity is 1-5 W·m -1 ·K -1 It can ensure temperature difference transmission to drive the second hydrogel layer 4, and be compatible with light transmittance and processability.

[0123] For example, the material of the separation layer 3 can be selected from FTO glass, ITO glass, inorganic dense coating composite film (for example, taking PET or glass as the base, depositing SiO2, Al2O3 or SiO x N y As ion blocking, cooperate with thin oxide layer heat conduction) and transparent polymer composite film (for example, taking PVB, PMMA, PC or PI as the base, taking low volume fraction of Al2O3 or BN nano filler to improve thermal conductivity and maintain transparency). When stronger blocking is required, inorganic / organic multilayer laminates (such as PET / SiO2 / Al2O3 / organic adhesive layer) can significantly reduce ion penetration while maintaining the target thermal conductivity and optical performance.

[0124] In an exemplary embodiment, the thickness of the first hydrogel layer 2 is 1.0-5.0 mm;

[0125] The thickness of the second hydrogel layer 4 is 1.0-5.0 mm;

[0126] The thickness of the separation layer 3 is 1.0-5.0 mm.

[0127] In this embodiment, the energy-saving building structure adopts a sandwich packaging, and the overall structure is about 1.9 cm thick. The first hydrogel layer 2 with a thickness of 1.0-5.0 mm can provide excellent heat regulation capability, maintain a faster heat response speed, and have a lower production difficulty. Exemplarily, the thickness of the first hydrogel layer 2 can be 1.0 mm, 2.2 mm, 3.4 mm, 4.5 mm, or 5.0 mm. The thickness of the first hydrogel layer 2 can also be any value between the exemplary thickness values, for example, the thickness of the first hydrogel layer 2 can also be any value between 2.2 mm and 4.5 mm.

[0128] Figures 11-14The images show a comparison of the appearance of the flowers covered by the first hydrogel layer 2 of different thicknesses at different temperatures. Figure 11 An initial image showing the flower before it is obscured by the first hydrogel layer 2.

[0129] Figure 12 The first hydrogel layer 2, with thicknesses of 1mm, 2mm, and 3mm respectively, is shown in the image of the flower obscured at 10℃, from top to bottom. Figure 13 The first hydrogel layer 2, with thicknesses of 1mm, 2mm, and 3mm respectively, is shown in the image at 25℃, obscuring the appearance of the flower. Figure 14 The first hydrogel layer 2, with thicknesses of 1mm, 2mm, and 3mm respectively, is shown in the image below, obscuring the appearance of the flower at 40℃. (Combined with...) Figures 11-14 It can be seen that as the thickness of the first hydrogel layer 2 increases, it can exhibit a higher degree of opacity at both low and high temperatures, thus providing better thermal insulation.

[0130] The thickness of the second hydrogel layer 4 is equal to the electrode spacing, typically in the sub-millimeter to millimeter range, and its thickness directly affects output performance. If the thickness is too thick, the electrolyte resistance increases, and the short-circuit current density decreases; if the thickness is too thin, fabrication becomes difficult, and temperature difference maintenance becomes unstable. Therefore, the thickness of the second hydrogel layer 4 is in the range of 1.0-5.0 mm to balance performance and engineering feasibility. For example, the thickness of the second hydrogel layer 4 can be 1.0 mm, 2.5 mm, 3.5 mm, 4.1 mm, or 5.0 mm. The thickness of the first hydrogel layer 2 can also be any value between the exemplary thickness values; for example, the thickness of the second hydrogel layer 4 can also be any value between 2.5 and 3.5 mm.

[0131] The thickness of the isolation layer 3 is in the range of 1.0-5.0 mm, which can serve as a physical barrier while also providing good interfacial optical transparency and thermal conductivity. For example, the thickness of the isolation layer 3 can be 1.0 mm, 1.8 mm, 2.2 mm, 3.0 mm, 4.5 mm, or 5.0 mm. The thickness of the isolation layer 3 can also be any value between the exemplary thickness values; for example, the thickness of the isolation layer 3 can be any value between 1.8 and 3.0 mm.

[0132] like Figure 15 As shown, an exemplary embodiment of this application provides a method for preparing an energy-saving building structure based on hydrogel. The method is used to prepare the energy-saving building structure based on hydrogel as described in any of the above embodiments. The method includes:

[0133] S110. An isolation layer is placed in the casting mold so that the isolation layer divides the casting mold into a first casting area and a second casting area.

[0134] S120, pouring a first hydrogel material into the first pouring area to form a first hydrogel layer.

[0135] S130, pouring a second hydrogel material into the second pouring area to form a second hydrogel layer.

[0136] S140, mounting a first substrate on a side of the first hydrogel layer away from the isolation layer.

[0137] S150, mounting a second substrate on a side of the second hydrogel layer away from the isolation layer to form an energy-saving building structure.

[0138] In this embodiment, the first hydrogel layer 2 and the second hydrogel layer 4 are isolated by the isolation layer 3, so that they can work independently but also cooperatively; the first substrate 1 and the second substrate 5 provide support stability, so as to obtain an energy-saving building structure which is simple in structure and easy to scale up.

[0139] Compared with traditional energy-saving building structures, the energy-saving building structure of the present application has the following significant advantages:

[0140] High functional integration: optical regulation and thermoelectric energy harvesting are integrated, and the structure is simple and easy to scale up.

[0141] Dual-threshold phase change design: meets the demand of bidirectional thermal management in different seasons, and improves building energy efficiency throughout the year.

[0142] Excellent optical performance: high light transmittance and high solar modulation ability are combined to maintain natural indoor lighting and comfort.

[0143] Continuous power generation capability: still uses temperature difference to generate electricity under non-light conditions, making up for the limitations of photovoltaic systems.

[0144] Preparation and application scalability: the material source is wide, the preparation process is simple, and it is suitable for building glass, vehicle sunroof, greenhouse and other multi-scene applications.

[0145] In order to more clearly explain the technical solutions of the present application, the present application lists specific embodiments of the energy-saving building structure based on hydrogel, and the beneficial effects of selecting the above-mentioned range of component content will be illustrated by specific experimental data.

[0146] Embodiment

[0147] It should be noted that, unless otherwise specified, the raw materials in the following embodiments can be obtained from the market.

[0148] Embodiment 1: A preparation method of an energy-saving building structure based on hydrogel, comprising the following steps:

[0149] (1) An isolation layer is placed in the casting mold, so that the isolation layer divides the casting mold into a first casting area and a second casting area. The isolation layer is selected from ITO glass and has a thickness of 3.0 mm.

[0150] (2) Preparation of the first hydrogel material: 4.5% w / v C 16 MeImSal and 1.0 % w / v pNIPAm are physically compounded in deionized water to form a first hydrogel material. The first hydrogel material is then poured into a first casting area to form a first hydrogel layer. The thickness of the first hydrogel layer is 3.0 mm.

[0151] (3) Preparation of the second hydrogel material: 32.5 wt% Pluronic F127, 0.21 mol / L Fe(CN)6 3- / Fe(CN)6 4- 0.5 mol / L GdmCl was mixed with deionized water and stirred until homogeneous to obtain a second hydrogel material. The second hydrogel material was then poured into a second casting area to form a second hydrogel layer. The thickness of the second hydrogel layer was 3.0 mm.

[0152] (4) A first substrate is installed on the side of the first hydrogel layer away from the isolation layer. The first substrate is selected from ITO glass and has a thickness of 5.0 mm.

[0153] (5) A second substrate is installed on the side of the second hydrogel layer away from the isolation layer to form an energy-saving building structure. The second substrate is selected from ITO glass with a thickness of 5.0 mm.

[0154] like Figure 16 As shown, Figure 16 In the graph, the horizontal axis represents the time period of a day, and the vertical axis represents the temperature (°C). Figure 16 In the diagram, curve K represents a blank window in summer, i.e., a window frame without glass or other transparent materials; curve L represents an energy-efficient building structure in summer; curve M represents an energy-efficient building structure in winter; and curve N represents a blank window in winter. According to... Figure 16 As can be seen, the energy-saving building structure in this embodiment can provide heat insulation in summer and heat preservation in winter, thereby achieving energy saving and temperature control.

[0155] like Figure 17 As shown, Figure 17 In the diagram, the horizontal axis represents the time period of a day, and the vertical axis represents the open-circuit voltage OCV (mV). Figure 17 In the diagram, curve O represents the energy-efficient building structure in summer, and curve P represents the energy-efficient building structure in winter; according to Figure 17It can be seen that the energy-saving building structure of the embodiment can continuously output voltage under day and night temperature, showing its stable power generation performance.

[0156] In order to more clearly explain the technical solutions of the present application, the present application also lists embodiments 2-7 of the energy-saving building structure, wherein the formulations of embodiments 2-7 are shown in Table 1.

[0157] Table 1 shows specific embodiments of the energy-saving building structure in the present application. It should be pointed out that, in addition to the parameters listed in Table 1, the other parameters of embodiments 2-7 are basically the same as those of embodiment 1.

[0158] Table 1 shows the formulations of each layer of the energy-saving building structure of the embodiment.

[0159]

[0160] Performance test

[0161] The performance of the energy-saving building structure of the embodiment is tested according to the following method, and the test structure is recorded in Table 2.

[0162] 1. Non-phase change region visible light transmittance: The non-phase change region visible light transmittance refers to the light transmittance of the hydrogel in the visible light range when the temperature has not reached the phase change temperature. The light transmittance test is carried out by using a UV-Vis spectrophotometer.

[0163] 2. Modulation efficiency ΔΓ sol : The modulation efficiency is the change amplitude of the optical transmittance of the hydrogel in the temperature change process, which is used to describe the response ability of the hydrogel to adjust the light transmittance. By measuring the optical transmittance change of the hydrogel at different temperatures, the ratio of the transmittance change is calculated to obtain the modulation efficiency.

[0164] 3. Thermoelectric potential: The thermoelectric potential is the potential difference generated by the thermoelectric effect of the hydrogel, which is usually proportional to the temperature gradient, and represents the electric potential generated by the hydrogel under the action of the temperature gradient. The test is carried out according to GB / T 13423-2017 "General method for thermoelectric potential measurement".

[0165] 4. Power density: The power density refers to the unit area electric power generated by the hydrogel under a certain temperature difference, which is used to evaluate the energy output ability of the thermoelectric material. The output voltage and current are measured, and the power density is calculated by the following formula: P=V×I; wherein P is the power density, V is the voltage, and I is the current, unit is W·m -2 .

[0166] 5. Thermoelectric conversion efficiency: The thermoelectric conversion efficiency is the ratio of the electric power generated by the hydrogel under the action of a temperature gradient to the input thermal power, reflecting its thermoelectric conversion capability. The thermoelectric conversion efficiency is calculated by the following formula:

[0167] η = Pin / Pout Wherein, Pout is the output power, Pin is the input thermal power (which can be calculated by the temperature difference and the thermal conductivity).

[0168] Table 2 Performance test table of the energy-saving building structure of the example

[0169]

[0170] It can be seen from the data in Table 1 and Table 2 that the proportion of each component in the first hydrogel layer and the second hydrogel layer in the energy-saving building structure has a certain influence on the performance of the product. By adjusting the proportion of each component in the first hydrogel layer and the second hydrogel layer, the energy-saving building structure can simultaneously have good transparency, double-temperature regulation function and electric energy collection function.

[0171] In summary, to solve the problem that the traditional phase change intelligent window can only rely on temperature change for passive regulation and cannot inhibit heat diffusion based on temperature difference, the present application proposes an energy-saving building structure based on hydrogel. The structure takes the first hydrogel layer and the second hydrogel layer as the core modular double-layer structure, separates optical regulation from thermoelectric conversion, and realizes mutual independent optimization. The modular double-layer structure can avoid damage to the optical performance, and takes into account transparency, energy saving and electric energy collection function. The first hydrogel layer on the outer layer provides >80% solar transmittance regulation and high-contrast double-temperature zone phase change switching. The second hydrogel layer on the inner layer utilizes the dynamic redox cycle of redox ion pairs to generate a potential difference based on environmental temperature difference, and realizes the conversion of low-grade heat energy into electric energy; to realize stable thermoelectric output and actively recover environmental heat energy.

[0172] Compared with traditional low-emissivity glass or vacuum glass, the energy-saving building structure of the present application not only has dynamic light and heat regulation, but also realizes the multifunctional combination of transparency, energy saving and energy self-sufficiency. Compared with a single-layer phase change intelligent window, it realizes the functional transition from "passive temperature control" to "active energy recovery". The energy-saving building structure of the present application can adapt to seasonal and diurnal temperature fluctuations, and has significant cumulative energy saving and sustainable potential in the application of large-area glass curtain walls in high-rise buildings.

[0173] It should be noted that in this document, the terms "comprising", "including" or any other variant thereof are intended to cover non-exclusive inclusion, so that a process, method, article or equipment including a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such a process, method, article or equipment.

[0174] The above examples are only used to illustrate the technical solutions of the present application, but not to limit it. Although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those skilled in the art that the technical solutions recorded in the foregoing embodiments can be modified, or some technical features can be replaced by equivalent ones, and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. An energy-saving building structure based on hydrogel, characterized in that, The energy-saving building structure is used to isolate a first space and a second space, wherein the first space has a first ambient temperature and the second space has a second ambient temperature. In the direction from the first space to the second space, the energy-saving building structure includes a first substrate, a first hydrogel layer, an isolation layer, a second hydrogel layer, and a second substrate stacked together; The first hydrogel layer has a first phase transition temperature and a second phase transition temperature. When the first ambient temperature is below the first phase transition temperature or above the second phase transition temperature, the first hydrogel layer is opaque. When the first ambient temperature is between the first phase transition temperature and the second phase transition temperature, the first hydrogel layer is transparent. When the temperature difference between the first ambient temperature and the second ambient temperature is greater than or equal to a preset threshold, the second hydrogel layer can perform thermoelectric conversion.

2. The hydrogel-based energy-saving building structure according to claim 1, characterized in that, The first hydrogel layer is formed of a first hydrogel material, which comprises components at the following concentrations: Low molecular weight ionic surfactants: 4.45-10.00 %w / v; Thermosensitive polymers 1.0-9.0 %w / v.

3. The hydrogel-based energy-saving building structure according to claim 2, characterized in that, The low molecular weight ionic surfactant includes 1-hexadecyl-3-methylimidazolium salicylate; and / or The thermosensitive polymer includes poly(N-isopropylacrylamide).

4. The energy-saving building structure based on hydrogel according to claim 1, characterized in that, The second hydrogel layer is formed of a second hydrogel material, which comprises components at the following concentrations: Hydrogel matrix 32.5-49.0 wt% Redox ion pairs: 0.21–0.46 mol / L.

5. The hydrogel-based energy-saving building structure according to claim 4, characterized in that, The hydrogel matrix comprises a triblock copolymer of polyethylene oxide-polypropylene oxide-polyethylene oxide; and / or The redox ion pair includes Fe(CN)6 3- / Fe(CN)6 4- , K3[Co(CN)6] / K4[Co(CN)6], [Ru(NH3)6] 3+ / [Ru(NH3)6] 2+ One or more of them.

6. The hydrogel-based energy-saving building structure according to claim 4, characterized in that, The second hydrogel material also includes components at the following concentrations: Strongly ionizable additives: 0.5-1.4 mol / L.

7. The hydrogel-based energy-saving building structure according to claim 6, characterized in that, The strong ionizing additives include one or more of guanidine hydrochloride, guanidine nitrate, guanidine carbonate, lithium chloride, zinc chloride, and magnesium chloride.

8. The energy-saving building structure based on hydrogel according to claim 1, characterized in that, The isolation layer is a transparent thermally conductive film with a light transmittance of ≥90% and a thermal conductivity of 1-5 W·m. -1 ·K -1 .

9. The hydrogel-based energy-saving building structure according to claim 1, characterized in that, The thickness of the first hydrogel layer is 1.0-5.0 mm; The thickness of the second hydrogel layer is 1.0-5.0 mm; The thickness of the isolation layer is 1.0-5.0 mm.

10. A method for preparing an energy-saving building structure based on hydrogel, characterized in that, The preparation method is used to prepare the hydrogel-based energy-saving building structure as described in any one of claims 1-9, and the preparation method includes: The isolation layer is placed in the casting mold, so that the isolation layer divides the casting mold into a first casting area and a second casting area; The first hydrogel material is poured into the first casting area to form the first hydrogel layer; A second hydrogel material is poured into the second casting area to form the second hydrogel layer; The first substrate is installed on the side of the first hydrogel layer opposite to the isolation layer; The second substrate is installed on the side of the second hydrogel layer opposite to the isolation layer to form the energy-saving building structure.

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