Radiation refrigeration and thermal insulation integrated aerogel material as well as preparation method and application thereof

Abstract

The invention relates to the technical field of composite radiation refrigeration and heat preservation and insulation materials, and discloses a radiation refrigeration and heat preservation and insulation integrated aerogel material and a preparation method and application thereof. The method comprises the following steps: dispersing an organic dispersant in water to obtain an organic dispersion liquid; the preparation method comprises the following steps: adding an organosilicon compound into an acetic acid aqueous solution, and hydrolyzing to obtain precursor sol; dispersing glass fibers in the organic dispersion liquid, adding the precursor sol, and uniformly stirring to obtain a glass fiber dispersion liquid; dispersing silicon dioxide particles in tert-butyl alcohol to obtain silicon dioxide dispersion liquid; adding a silicon dioxide dispersion liquid and aluminum oxide particles into the glass fiber dispersion liquid, and uniformly stirring to obtain a precursor suspension liquid; freeze-drying the precursor suspension to obtain the radiation refrigeration and thermal insulation integrated aerogel material. The aerogel material prepared by the invention has low thermal conductivity, excellent optical performance and high radiation cooling performance, and has dual functions of radiation refrigeration and thermal insulation.

Description

Technical Field

[0001] The present application relates to the technical field of composite radiation refrigeration and thermal insulation materials, and specifically to an aerogel material integrating radiation refrigeration and thermal insulation, and a preparation method and application thereof. Background Art

[0002] Maintaining a suitable indoor temperature is of great significance to industrial manufacturing, agricultural production and human indoor activities. At present, indoor temperature is mainly regulated by heating or cooling air conditioners, which consumes a lot of electric energy. Studies have shown that building energy consumption accounts for about 30% of the world's total energy consumption, of which 20-30% comes from the heating and cooling needs of buildings. According to analysis, by 2050, global building cooling energy consumption will surge from 2020TWh in 2016 to 6200TWh.

[0003] Radiative cooling is a new type of passive cooling technology that emits thermal radiation to the atmospheric window (8-13μm) through materials, which can achieve cooling without consuming additional energy. However, existing radiative cooling materials still face the following key problems in practical applications: 1. The continuous radiative cooling effect at night causes the building temperature to be too low, which in turn increases the heating energy consumption. This is mainly because traditional radiative cooling materials lack intelligent regulation capabilities and continue to radiate heat at night, causing the heat inside the building to continue to be lost; 2. Existing radiative cooling materials such as coatings, films and other materials generally have poor thermal insulation properties. This results in unsatisfactory overall insulation effect of the building envelope, requiring the building to consume more energy to maintain indoor temperature during the heating season.

[0004] At present, aerogel materials have shown good application prospects in the field of building energy conservation due to their ultra-low thermal conductivity and adjustable pore structure. However, pure aerogel materials mainly play a role in thermal insulation and it is difficult to achieve radiative cooling function. How to organically combine the excellent thermal insulation performance of aerogel with the radiative cooling function is a technical problem that needs to be solved urgently. Summary of the invention

[0005] The present application provides an aerogel material integrating radiative cooling and thermal insulation, and a preparation method and application thereof, aiming to solve the problem that existing aerogel materials are difficult to have both thermal insulation performance and radiative cooling function.

[0006] In order to achieve the above objectives, the present application adopts the following technical solutions.

[0007] In a first aspect of the present application, a method for preparing an aerogel material integrating radiative cooling and thermal insulation is provided, comprising:

[0008] dispersing an organic dispersant in water to obtain an organic dispersion;

[0009] The organosilicon compound is added into an acetic acid aqueous solution and hydrolyzed to obtain a precursor sol;

[0010] Dispersing glass fibers in the organic dispersion, adding precursor sol, and stirring evenly to obtain a glass fiber dispersion;

[0011] Dispersing silicon dioxide particles in tert-butyl alcohol to obtain a silicon dioxide dispersion; adding the silicon dioxide dispersion and aluminum oxide particles to the glass fiber dispersion, and stirring evenly to obtain a precursor suspension;

[0012] The precursor suspension is freeze-dried to obtain a radiation refrigeration and thermal insulation integrated aerogel material.

[0013] Preferably, the organic dispersant includes any one of hydroxymethyl cellulose, carboxymethyl cellulose, ethyl cellulose, cellulose ether, sodium polyacrylate, polyvinyl alcohol, a surfactant, a polyelectrolyte or polystyrene sulfonate.

[0014] Preferably, the organosilicon compound includes any one of methyltrimethoxysilane, ethyl silicate, propyl silicate or n-butyl silicate.

[0015] Preferably, the glass fiber is a mixture of glass fibers of different diameters;

[0016] The diameter is 400-600 nm.

[0017] Preferably, the concentration of the organic dispersion is 0.1 to 0.5 wt %;

[0018] The concentration of the acetic acid aqueous solution is 0.028-0.032 wt %;

[0019] The mass ratio of the organosilicon compound to the acetic acid aqueous solution is 1:3 to 3.5.

[0020] Preferably, the particle size of the aluminum oxide particles is micrometer-sized, and the particle size of the silicon dioxide particles is nanometer-sized;

[0021] The mass ratio of the alumina particles, the silica particles and the glass fibers is 1 to 5:1 to 5:1.

[0022] Preferably, the mass ratio of the glass fiber to the organic dispersion is 0.002 to 0.006:1;

[0023] In the glass fiber dispersion, the amount ratio of glass fiber to precursor sol is 0.068-0.125 mL of precursor sol per 1 g of glass fiber.

[0024] Preferably, the freeze-drying is specifically: first freezing at below -20°C, and then drying at below -10°C under vacuum conditions.

[0025] In a second aspect of the present application, there is provided an aerogel material integrating radiative cooling and thermal insulation prepared by the above-mentioned preparation method.

[0026] The third aspect of the present application provides the application of the above-mentioned radiative cooling and thermal insulation integrated aerogel material in radiative cooling and building thermal management.

[0027] Compared with the prior art, the beneficial effects of this application are:

[0028] The aerogel material prepared in this application has the dual functions of radiation cooling and thermal insulation. On the one hand, it is a porous structure composited with silica and alumina, which improves the interfacial thermal resistance of the aerogel and makes the aerogel material have low thermal conductivity. On the other hand, the aerogel material prepared in this application achieves excellent radiation cooling performance based on the synergistic effect of the intrinsic properties of the material and the structural design; among them, based on the excellent optical properties of glass fiber and silica in the aerogel material, the emissivity of the aerogel material in the atmospheric window range of 8 to 13 microns reaches 98.3 to 99.5%, and it has high radiation cooling performance; at the same time, the wide size distribution in the aerogel material gives it a Mie scattering effect, and its reflectivity reaches 92.4 to 95.3% in the visible light band, further improving the radiation cooling performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments recorded in the present application, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0030] Figure 1 A physical picture of the integrated aerogel material for radiative cooling and thermal insulation prepared for this application;

[0031] Figure 2 SEM image of the aerogel material integrated with radiative cooling and thermal insulation prepared for this application;

[0032] Figure 3 This is an enlarged view of the SEM image of the radiative cooling and thermal insulation integrated aerogel material prepared in this application;

[0033] Figure 4 The reflectivity curve of the aerogel material integrated with radiative cooling and thermal insulation prepared in this application in the ultraviolet-visible-near infrared band;

[0034] Figure 5 The atmospheric window band emissivity curve of the aerogel material integrated with radiative cooling and thermal insulation prepared for this application;

[0035] Figure 6 Thermal conductivity test diagram of the integrated radiative cooling and thermal insulation aerogel material prepared for this application and the existing thermal insulation material;

[0036] Figure 7 A physical picture of the radiation cooling test device of this application;

[0037] Figure 8 This is a test curve of the cooling effect of the radiant cooling and thermal insulation integrated aerogel material prepared in this application in an outdoor environment. DETAILED DESCRIPTION

[0038] The technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0039] In the following description of this embodiment, the terms "include", "comprising", "having" and "containing" are all open terms, meaning including but not limited to.

[0040] In the following description of this embodiment, the term "and / or" is used to describe the association relationship of associated objects, indicating that there may be three relationships. For example, A and / or B can represent: A exists alone, B exists alone, and A and B exist at the same time. A and B can be singular or plural. The character " / " generally indicates that the associated objects before and after are in an "or" relationship.

[0041] In the following description of this embodiment, the term "at least one" refers to one or more, and "plurality" refers to two or more. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single items or plural items. For example, "at least one of a, b or c", or "at least one of a, b and c", can all represent: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, c can be single or multiple, respectively.

[0042] The terms used in the embodiments of the present application are only for the purpose of describing specific embodiments, and are not intended to limit the present application. The singular forms "a", "an" and "the" used in the embodiments of the present application and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings.

[0043] Those skilled in the art should understand that in the following description of the embodiments of the present application, the order of serial numbers does not mean the order of execution, some or all of the steps can be executed in parallel or sequentially, and the execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0044] Those skilled in the art will appreciate that the numerical ranges in the embodiments of the present application are to be construed as specifically disclosing each intermediate value between the upper and lower limits of the scope. Each smaller range between the intermediate value in any stated value or stated range and any other stated value or intermediate value in the described range is also included in the present application. The upper and lower limits of these smaller ranges may be independently included or excluded in the scope.

[0045] Unless otherwise specified, the technical / scientific terms used herein have the same meanings as those generally understood by those skilled in the art to which this application belongs. Although this application only describes preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of this application. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials related to the documents. In the event of a conflict with any incorporated document, the content of this specification shall prevail.

[0046] In a first aspect, the present application provides a method for preparing an aerogel material integrating radiative cooling and thermal insulation, comprising:

[0047] dispersing an organic dispersant in water to obtain an organic dispersion;

[0048] The organic dispersant can be selected from any one of hydroxymethyl cellulose, carboxymethyl cellulose, ethyl cellulose, cellulose ether, sodium polyacrylate, polyvinyl alcohol, surfactant, polyelectrolyte or polystyrene sulfonate. The concentration of the organic dispersion is 0.1-0.5wt%, preferably 0.2wt%. Specifically, the organic dispersant is dispersed in water and uniformly dispersed by ultrasonic stirring or mechanical stirring, preferably ultrasonic stirring.

[0049] The organosilicon compound is added into an acetic acid aqueous solution and hydrolyzed to obtain a precursor sol;

[0050] In the present application, the organic silicon compound includes any one of methyltrimethoxysilane, ethyl silicate, propyl silicate or n-butyl silicate.

[0051] In the present application, the concentration of the aqueous acetic acid solution is preferably 0.028-0.032 wt%, more preferably 0.03 wt%; the mass ratio of the organosilicon compound to the aqueous acetic acid solution is preferably 1:3-3.5.

[0052] In the present application, the organosilicon compound is mixed with an acetic acid aqueous solution and stirred to cause a hydrolysis-condensation reaction, wherein the stirring speed is 500-700 rpm and the time is 10-30 minutes. Under the action of acetic acid, the organosilicon compound is hydrolyzed to generate silanol (-Si-OH), and the silanol condenses to form a silicon-oxygen bond (-Si-O-Si-) network structure, and finally forms a quasi-colloidal system containing a silicon-oxygen network structure. Acetic acid can control the hydrolysis rate, adjust the pH value, and improve the stability of the sol.

[0053] Dispersing glass fibers in the organic dispersion, adding precursor sol, and stirring evenly to obtain a glass fiber dispersion;

[0054] In the present application, the organic dispersant in the organic dispersion disperses the glass fibers through electrostatic stabilization and steric hindrance. Its charged groups form a double electric layer, generating electrostatic repulsion, so that the glass fibers are evenly dispersed; its polymer chains stretch to form a protective layer, which can effectively prevent the fibers from contacting and agglomerating. In addition, the organic dispersant can also improve the ability to emit sunlight during radiative cooling.

[0055] In the present application, the precursor sol can be used as a coupling agent to form a chemical bond bridge on the surface of the glass fiber, improve the compatibility and adhesion between the glass fiber and the resin matrix, and improve the interface bonding strength of the final aerogel material. In addition, it can reduce the surface energy of the glass fiber, improve the wettability and dispersibility of the glass fiber; it can also prevent hydrolysis damage on the surface of the glass fiber, reduce its surface defects, and improve its durability and service life.

[0056] In the present application, the mass ratio of the glass fiber to the organic dispersion is 0.002-0.005:1, preferably 0.004:1; in the glass fiber dispersion, the amount ratio of the glass fiber to the precursor sol is 0.068-0.125 mL of the precursor sol per 1 g of glass fiber.

[0057] In the present application, the glass fiber is a mixture of glass fibers with different diameters, and the diameter is 400-600 nm. As an example, the glass fiber of the present application can be a mixture of glass fibers with diameters of 400 nm, 500 nm and 600 nm in a weight ratio of 1:1:1.

[0058] The silica particles are dispersed in tert-butyl alcohol to obtain a silica dispersion; the silica dispersion and alumina particles are added to the glass fiber dispersion, and stirred evenly to obtain a precursor suspension; wherein the alumina particles have a particle size of micrometer level, and the silica particles have a particle size of nanometer level.

[0059] In the present application, the mass ratio of the alumina particles, silica particles and glass fibers is preferably 1 to 5: 1 to 5: 1, and more preferably 3: 3: 1. The stirring may be ultrasonic stirring or mechanical stirring, preferably ultrasonic stirring.

[0060] The precursor suspension is freeze-dried to obtain a radiation refrigeration and thermal insulation integrated aerogel material.

[0061] In the present application, the freeze drying specifically includes: first freezing at a temperature below -20°C, and then drying at a temperature below -10°C under vacuum conditions.

[0062] The aerogel material prepared in the present application has glass fiber as the main frame, and alumina particles and silica particles are evenly distributed in the glass fiber. It has a porous structure with silica and alumina, which improves the interfacial thermal resistance of the aerogel and makes the aerogel material have low thermal conductivity, and its thermal conductivity is only 0.0328W / mk. In addition, the aerogel material prepared in the present application achieves excellent radiation cooling performance based on the synergistic effect of the intrinsic properties of the material and the structural design; among them, the high emissivity of the glass fiber and silica in the aerogel material makes the aerogel material have an emissivity of 98.3-99.5% in the atmospheric window range of 8-13 microns, and has high radiation cooling performance; at the same time, the wide size distribution in the aerogel material makes it have a Mie scattering effect, and its reflectivity reaches 92.4-95.3% in the visible light band, further improving the radiation cooling performance.

[0063] The aerogel material prepared in the present application has the dual functions of radiative cooling and thermal insulation, and can be used for radiative cooling and building thermal management.

[0064] The present application is further described below through specific examples.

[0065] The raw materials involved in this application come from the following sources:

[0066] Glass fiber: Nanjing Glass Fiber Research and Design Institute

[0067] Alumina (purity ≥ 95%): Kaifeng Datong Refractory Materials Co., Ltd.

[0068] Tert-Butanol (AR grade): Shanghai Myril Biochemical Technology Co., Ltd.

[0069] Hydroxymethylcellulose (AR grade, viscosity 100,000): Shanghai Yuanye Biotechnology Co., Ltd.

[0070] Silicon dioxide (AR grade): Merck Chemical Technology (Shanghai) Co., Ltd.

[0071] MTMS (methyltrimethoxysilane) (RG grade): Shanghai Myril Biochemical Technology Co., Ltd.

[0072] Acetic acid (purity> 95%): Shanghai Yuanye Biotechnology Co., Ltd.

[0073] Example 1

[0074] This embodiment provides a method for preparing an aerogel material integrating radiation cooling and thermal insulation, comprising:

[0075] 1 g of hydroxymethyl cellulose was added to 500 g of water and ultrasonically stirred to obtain a 0.2 wt% hydroxymethyl cellulose dispersion;

[0076] 30 μL of acetic acid was slowly added to 100 mL of deionized water, and stirred evenly to obtain an acetic acid aqueous solution; 2 mL of MTMS was added to 6 mL of acetic acid aqueous solution, and stirred at 600 rpm for 30 min to obtain a precursor sol;

[0077] 0.1 g of glass fibers with diameters of 400 nm, 500 nm, and 600 nm were added to 50 g of hydroxymethyl cellulose dispersion, and then 37.5 μL of precursor sol was added and mixed evenly to obtain a glass fiber dispersion;

[0078] 0.9 g of SiO2 particles were added to 45 g of tert-butyl alcohol solution, mixed evenly and centrifuged to obtain SiO2 dispersion; the SiO2 dispersion and 0.9 g of Al2O3 particles in glass fiber dispersion were ultrasonically stirred to obtain a precursor suspension;

[0079] The composite suspension was divided into plastic dishes, placed in a freezing chamber at -20°C for 12 hours, and dried at -10°C under vacuum conditions for 72 hours to obtain an aerogel material integrating radiation refrigeration and thermal insulation.

[0080] Example 2

[0081] This embodiment provides a method for preparing an aerogel material integrating radiation cooling and thermal insulation, comprising:

[0082] 1 g of hydroxymethyl cellulose was added to 500 g of water and stirred at 700 rpm for 5 h to obtain a 0.2 wt% hydroxymethyl cellulose dispersion;

[0083] 30 μL of acetic acid was slowly added to 100 mL of deionized water, and stirred evenly to obtain an acetic acid aqueous solution; 2 mL of MTMS was added to 6 mL of acetic acid aqueous solution, and stirred at 600 rpm for 30 min to obtain a precursor sol;

[0084] 0.1 g of glass fibers with diameters of 400 nm, 450 nm, and 550 nm were added to 50 g of hydroxymethyl cellulose dispersion, and then 28.13 μL of precursor sol was added and mixed evenly to obtain a glass fiber dispersion;

[0085] 0.9 g of SiO2 particles were added to 45 g of tert-butyl alcohol solution, mixed evenly and centrifuged to obtain SiO2 dispersion; the SiO2 dispersion and 0.6 g of Al2O3 particles in glass fiber dispersion were added and ultrasonically stirred to obtain a precursor suspension;

[0086] The composite suspension was divided into plastic dishes, placed in a freezing chamber at -20°C for 12 hours, and dried at -10°C under vacuum conditions for 72 hours to obtain an aerogel material integrating radiation refrigeration and thermal insulation.

[0087] Example 3

[0088] This embodiment provides a method for preparing an aerogel material integrating radiation cooling and thermal insulation, comprising:

[0089] 1 g of hydroxymethyl cellulose was added to 500 g of water, and ultrasonically stirred to obtain a 0.2 wt% hydroxymethyl cellulose dispersion;

[0090] 30 μL of acetic acid was slowly added to 100 mL of deionized water, and stirred evenly to obtain an acetic acid aqueous solution; 2 mL of MTMS was added to 6 mL of acetic acid aqueous solution, and stirred at 600 rpm for 30 min to obtain a precursor sol;

[0091] 0.1 g of glass fibers with diameters of 400 nm, 550 nm, and 600 nm were added to 50 g of hydroxymethyl cellulose dispersion, and then 20.63 μL of precursor sol was added and mixed evenly to obtain a glass fiber dispersion;

[0092] 0.9 g of SiO2 particles were added to 45 g of tert-butyl alcohol solution, mixed evenly and centrifuged to obtain SiO2 dispersion; the SiO2 dispersion and 0.3 g of Al2O3 particles in glass fiber dispersion were added and ultrasonically stirred to obtain a precursor suspension;

[0093] The composite suspension was divided into plastic dishes, placed in a freezing chamber at -20°C for 12 hours, and dried at -10°C under vacuum conditions for 72 hours to obtain an aerogel material integrating radiation refrigeration and thermal insulation.

[0094] Example 4

[0095] This embodiment provides a method for preparing an aerogel material integrating radiation cooling and thermal insulation, comprising:

[0096] 2.49 g of hydroxymethyl cellulose was added to 500 g of water and ultrasonically stirred to obtain a 0.5 wt% hydroxymethyl cellulose dispersion;

[0097] 30 μL of acetic acid was slowly added to 100 mL of deionized water, and stirred evenly to obtain an acetic acid aqueous solution; 2 mL of MTMS was added to 6 mL of acetic acid aqueous solution, and stirred at 600 rpm for 30 min to obtain a precursor sol;

[0098] 0.1 g of glass fibers with diameters of 400 nm, 500 nm, and 600 nm were added to 75 g of hydroxymethyl cellulose dispersion, and then 37.5 μL of precursor sol was added and mixed evenly to obtain a glass fiber dispersion;

[0099] 0.9 g of SiO2 particles were added to 45 g of tert-butyl alcohol solution, mixed evenly and centrifuged to obtain SiO2 dispersion; the SiO2 dispersion and 0.9 g of Al2O3 particles in glass fiber dispersion were ultrasonically stirred to obtain a precursor suspension;

[0100] The composite suspension was divided into plastic dishes, placed in a freezing chamber at -20°C for 12 hours, and dried at -10°C under vacuum conditions for 72 hours to obtain an aerogel material integrating radiation refrigeration and thermal insulation.

[0101] Example 5

[0102] The difference between Example 5 and Example 1 is that hydroxymethyl cellulose is replaced by carboxymethyl cellulose, and MTMS is replaced by ethyl silicate. The rest is the same as Example 1.

[0103] The aerogel material prepared in Example 1 is shown in the figure Figure 1 As shown, it is white and has a porous structure.

[0104] The morphology of the integrated aerogel material for radiative cooling and thermal insulation prepared in Example 1 was tested, and its SEM image is as follows: Figure 2 and Figure 3 As shown. Figure 2 It can be seen that the aerogel material prepared in the present application has a porous structure and is loaded with SiO2 particles and Al2O3 particles, which, on the one hand, enables the aerogel material to have excellent thermal insulation properties, and on the other hand, can effectively improve the radiation cooling performance of the aerogel and improve the mechanical strength of the aerogel material.

[0105] from Figure 3 It can be seen that the aerogel material has blocky Al2O3 and spherical nano-SiO2 particles, and the nano-SiO2 particles are coated on the surface of Al2O3, which makes the aerogel material have Mie scattering effect, further enhancing the reflection of light and improving the radiation cooling performance.

[0106] The performance of the aerogel material of Example 1 was characterized as follows:

[0107] 1. Reflectivity, tested using UV-Vis-NIR device, the UV-Vis-NIR reflectivity curve is as follows: Figure 4 As shown. Figure 4 It can be seen that it has excellent spectral performance as a radiation cooling material, with an average reflectivity of 95% under the AM1.5 (atmospheric mass) solar spectrum.

[0108] 2. The atmospheric window band emissivity is measured and tested using an infrared spectrometer. The atmospheric window band emissivity curve is as follows: Figure 5 As shown. Figure 5 It can be seen that it produces an emissivity of 98% under the atmospheric transparent window and has excellent radiation cooling performance.

[0109] The thermal conductivity of the aerogel material of Example 1 was tested and compared with the existing thermal insulation material polystyrene foam. The test results are as follows: Figure 6 As shown, from Figure 6 It can be seen that the thermal conductivity of the aerogel material prepared in the present application is 0.0328W / mk, while the thermal conductivity of the existing thermal insulation material is 0.0423W / mk. The thermal conductivity of the aerogel material in the present application is significantly lower than that of the existing thermal insulation material, and has a better thermal insulation effect. This is because the aerogel material in the present application not only has a porous structure, which makes it have low thermal conductivity; but also the micron-sized Al2O3 particles and nano-sized SiO2 will produce a large number of material interfaces, and a large number of interfaces can enhance phonon scattering and further reduce thermal conductivity.

[0110] A radiation cooling test device was built to test the cooling effect of the aerogel material of Example 1 in an outdoor environment. Figure 7 The middle left picture is a side view of the radiation cooling test device. Figure 7 The middle right picture is a top view of the radiation cooling test device. Figure 8 As shown, from Figure 8 It can be seen that when the sunlight intensity is 924.4W / m 2 When the temperature of the aerogel material of the present application is lowered to 11.9°C, the aerogel material has an excellent cooling effect.

[0111] The aerogel materials prepared in Examples 2-5 were tested and found to have excellent radiation cooling performance and excellent thermal insulation performance.

[0112] The aerogel material prepared in the present application has the dual functions of radiative cooling and thermal insulation, and has good mechanical properties. It can be used as a building material for radiative cooling and building thermal management.

[0113] Although the present application has been described in detail in general terms and in specific embodiments in this specification, it is obvious to those skilled in the art that some modifications or improvements may be made to the present application. Therefore, these modifications or improvements made without departing from the spirit of the present application are within the scope of protection claimed in the present application.

Claims

1. A method for preparing an aerogel material integrating radiation cooling and thermal insulation, characterized in that: include: dispersing an organic dispersant in water to obtain an organic dispersion; The organosilicon compound is added into an acetic acid aqueous solution and hydrolyzed to obtain a precursor sol; Dispersing glass fibers in the organic dispersion, adding precursor sol, and stirring evenly to obtain a glass fiber dispersion; Dispersing silicon dioxide particles in tert-butyl alcohol to obtain a silicon dioxide dispersion; adding the silicon dioxide dispersion and aluminum oxide particles to the glass fiber dispersion, and stirring evenly to obtain a precursor suspension; The precursor suspension is freeze-dried to obtain a radiation refrigeration and thermal insulation integrated aerogel material.

2. The preparation method according to claim 1, characterized in that: The organic dispersant includes any one of hydroxymethyl cellulose, carboxymethyl cellulose, ethyl cellulose, cellulose ether, sodium polyacrylate, polyvinyl alcohol, a surfactant, a polyelectrolyte or polystyrene sulfonate.

3. The preparation method according to claim 1, characterized in that: The organic silicon compound includes any one of methyltrimethoxysilane, ethyl silicate, propyl silicate or n-butyl silicate.

4. The preparation method according to claim 1, characterized in that: The glass fiber is a mixture of glass fibers of different diameters; The diameter is 400-600 nm.

5. The preparation method according to claim 1, characterized in that: The concentration of the organic dispersion is 0.1 to 0.5 wt %; The concentration of the acetic acid aqueous solution is 0.028-0.032 wt %; The mass ratio of the organosilicon compound to the acetic acid aqueous solution is 1:3 to 3.

5.

6. The preparation method according to claim 1, characterized in that: The particle size of the aluminum oxide particles is in the micrometer scale, and the particle size of the silicon dioxide particles is in the nanometer scale; The mass ratio of the alumina particles, the silica particles and the glass fibers is 1 to 5:1 to 5:

1.

7. The preparation method according to claim 1, characterized in that: The mass ratio of the glass fiber to the organic dispersion is 0.002 to 0.006:1; In the glass fiber dispersion, the amount ratio of glass fiber to precursor sol is 0.068-0.125 mL of precursor sol per 1 g of glass fiber.

8. The preparation method according to claim 1, characterized in that: The freeze drying specifically includes: first freezing at a temperature below -20°C, and then drying at a temperature below -10°C under vacuum conditions.

9. An aerogel material integrating radiation cooling and thermal insulation prepared by the preparation method according to any one of claims 1 to 8.

10. Application of the radiant cooling and thermal insulation integrated aerogel material according to claim 9 in radiant cooling and building thermal management.

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