Preparation method of composite heat storage material for building

Abstract

The application relates to a preparation method of a building composite heat storage material and belongs to the technical field of heat storage materials. The method comprises the following processes: after mullite powder is subjected to heat treatment, the mullite powder is fully stirred and uniformly mixed with beeswax and coconut oil to obtain mullite powder uniformly loaded with beeswax, then the mullite powder is mixed and stirred with silk protein modified expanded graphite, a dispersing agent and water to obtain a suspension, the suspension is subjected to spray drying to obtain a first mixture which is uniformly mixed; sodium bentonite, inorganic salt modified silicon carbide and a binder are continuously added and uniformly mixed, extrusion molding is carried out, heat preservation is carried out in a reducing atmosphere, and natural cooling is carried out to room temperature, so that the building composite heat storage material is prepared. The prepared composite heat storage material has excellent heat storage performance, can maintain good stability, and can long-term play a heat storage effect.

Description

Technical Field

[0001] This invention belongs to the field of thermal storage materials technology, and relates to a method for preparing a composite thermal storage material for buildings. Background Technology

[0002] Thermal energy storage technology aims to balance the uncoordinated relationship between energy supply and consumption in many energy utilization systems, thereby avoiding unreasonable energy use and excessive energy waste.

[0003] Currently, the main thermal storage materials are molten salt, concrete, rock, oil, and organic polymer materials. However, most of these thermal storage materials have some defects. For example, molten salt is prone to leakage, highly corrosive, and has poor service life and high temperature resistance. Concrete has a low thermal storage density and is prone to powdering after high temperature thermal shock. Rock-based thermal storage materials are limited by their own natural conditions, and their performance and shape are uncontrollable. Oil and organic polymer materials are prone to aging and failure as thermal storage materials, and have low operating temperatures.

[0004] Therefore, it is necessary to develop a composite thermal storage material for buildings that has both excellent thermal storage performance and good stability. Summary of the Invention

[0005] The purpose of this invention is to provide a method for preparing a composite thermal storage material for buildings, wherein the prepared composite thermal storage material has excellent thermal storage effect.

[0006] The objective of this invention can be achieved through the following technical solutions:

[0007] A method for preparing a composite thermal storage material for buildings includes the following steps;

[0008] S1. By mass, 10-15 parts of mullite powder are calcined in a muffle furnace for 4-5 hours at a temperature of 700-800℃, and then cooled to room temperature.

[0009] S2. At 60-70℃, fully melt 10-15 parts of a mixture of beeswax and coconut oil, then add 10-15 parts of mullite powder and stir thoroughly to obtain mullite powder uniformly loaded with beeswax.

[0010] S3. Mix 30-45 parts of modified expanded graphite, 10-15 parts of mullite powder uniformly loaded with beeswax, 2-3 parts of dispersant and 100-110 parts of water and stir for 1 hour, then treat with ultrasound for 3-5 hours to obtain a suspension.

[0011] The specific preparation process of the modified expanded graphite is as follows:

[0012] Expanded graphite was calcined at 650–700℃ for 1 hour, then heated to 720–750℃ and held for 1.5 hours before cooling to room temperature to obtain heat-treated expanded graphite. 20–30 parts of the heat-treated expanded graphite were added to 70–90 parts of a 3–5% (w / w) aqueous solution of silk protein, and stirred for 0.5 hours. Then, 2–5 parts of glutaraldehyde were added at 40–50℃, and the reaction was continued with stirring for 6–8 hours. After filtration and drying in a vacuum drying oven at 105℃, modified expanded graphite was obtained.

[0013] S4. The suspension is spray-dried to obtain a uniformly mixed first mixture;

[0014] S5. Continue to add 8-13 parts of sodium-based bentonite, 10-13 parts of modified silicon carbide and 3-7 parts of binder to the first mixture and mix evenly. Grind the mixture in a ball mill at 400 r / min for 3 hours, then knead it in a compounding extruder for 20 minutes, age it for 17 hours, and then extrude it into shape.

[0015] The composite thermal storage material for building is prepared by holding the material at 130-150℃ for 2 hours in a reducing atmosphere and then naturally cooling it to room temperature.

[0016] As a preferred embodiment of the present invention, in step S2, the mass ratio of beeswax to coconut oil is 1:1.

[0017] As a preferred embodiment of the present invention, in step S2, the stirring speed is 500-700 r / min and the stirring time is 1-1.5 h.

[0018] In a preferred embodiment of the present invention, in step S3, the dispersant is hydroxyethyl cellulose or hydroxymethyl cellulose.

[0019] As a preferred embodiment of the present invention, in step S3, the stirring speed is 500-600 r / min.

[0020] As a preferred technical solution of the present invention, in step S3, the preparation process of the silk protein aqueous solution is as follows: under the condition of 40°C, the silk protein is dissolved in 10mol / L LiBr solution, the resulting solution is poured into a cellulose dialysis bag with a flux of 12000, dialyzed with deionized water for 100h, and then prepared into a silk protein aqueous solution with a concentration of 5%.

[0021] As a preferred technical solution of the present invention, in step S4, during the spray drying process: the fan frequency of the spray dryer is 35.00Hz, the air inlet temperature is 150~180℃, and the creeping speed is 2~5RPM.

[0022] As a preferred embodiment of the present invention, the specific preparation process of the modified silicon carbide in step S5 is as follows:

[0023] Disodium hydrogen phosphate dodecahydrate and ammonium aluminum sulfate dodecahydrate in a mass ratio of 1:(1-1.5) were dissolved in water and ultrasonically dispersed. The uniformly dispersed solution was then heated to 105-110°C to completely evaporate the water. After drying, a solid material was obtained. The solid material was prepared into a saturated solution and silicon carbide was impregnated dropwise 5-10 times. Then the water was evaporated to obtain modified silicon carbide.

[0024] As a preferred embodiment of the present invention, in step S5, the binder is one of cellulose, polyvinyl alcohol and clay.

[0025] Heat treatment of mullite powder at 500-600℃ can reduce sparks and improve the stability of the powder. Furthermore, the density and crystallinity of the mullite powder increase after heat treatment, which is beneficial for material forming and maintaining structural integrity.

[0026] Beeswax has a porous structure and low thermal conductivity, containing numerous micropores and bubbles. These pores and bubbles trap air, forming a gas layer that hinders heat conduction. This allows beeswax to maintain a stable temperature in thermal storage materials, reducing heat loss and improving thermal storage efficiency. Beeswax also has a high latent heat value. When coconut oil and beeswax are mixed and heated, the coconut oil and beeswax melt and interpenetrate. Coconut oil contains medium-chain fatty acids, which enhance the thermal conductivity of beeswax.

[0027] Mullite powder has a high melting point and exhibits good stability under high-temperature conditions. This allows it to maintain stable performance in high-temperature environments, thus effectively storing and releasing heat energy. Furthermore, mullite powder possesses excellent creep resistance and corrosion resistance, meaning it maintains stable heat storage performance even in high-temperature and corrosive environments. The interaction between beeswax and mullite powder optimizes the microstructure of the mullite material, thereby improving heat transfer efficiency. Beeswax also reduces porosity and defects in the material, lowering thermal resistance and making it easier for heat to be transferred and stored within the ceramic material, thus enhancing the heat storage effect of the material.

[0028] Calcination of expanded graphite at 650–700℃ facilitates the redox reaction of carbon, further optimizing the pore structure of expanded graphite. It also removes impurities and moisture from the expanded graphite, improving its purity. Continuing to raise the temperature to 720–750℃ and holding for 1.5 hours increases the interatomic spacing in the expanded graphite lattice, forming more micropores and gas channels, thus optimizing its expansion performance. Furthermore, it enhances the oxidation resistance and chemical stability of expanded graphite and facilitates rapid heat transfer within it.

[0029] In this invention, glutaraldehyde is used as a crosslinking agent to induce a crosslinking reaction in silk fibroin in solution. Glutaraldehyde forms intermolecular crosslinks with lysine in the silk fibroin molecules, and covalent bonds are formed between the silk fibroin molecular chains, thereby enhancing the strength and thermal stability of the silk fibroin material. Through chemical crosslinking, the interaction forces between molecular chains are enhanced, thus reducing the mobility of the silk fibroin molecular chains and improving the thermal stability of the material, helping the heat storage material maintain stability within a certain temperature range. The crosslinking reaction of silk fibroin is carried out in a dispersion of expanded graphite. After filtration, the crosslinked structure of silk fibroin is uniformly attached to the surface of the expanded graphite without affecting the rich porous structure of the expanded graphite itself. This effectively protects the structure of the graphite layer. Furthermore, the unique fibrous network structure of silk fibroin can form a more complex network structure with the porous structure of expanded graphite, thereby further enhancing the adsorption and heat storage capacity of the expanded graphite.

[0030] Disodium hydrogen phosphate dodecahydrate and ammonium aluminum sulfate dodecahydrate are both hydrated salts that store and release energy through the endothermic and exothermic processes of water of crystallization. By compounding, the ratio of disodium hydrogen phosphate dodecahydrate and ammonium aluminum sulfate dodecahydrate can be adjusted to optimize the phase change temperature and heat storage density of the material. In this invention, a compound material is obtained by mixing modified expanded graphite and modified mullite powder with inorganic salt modified silicon carbide and sodium-based bentonite. This compound material can form a eutectic, reduce the phase change temperature and increase the latent heat of phase change, thereby enhancing the heat storage performance. When a compound inorganic salt is loaded onto silicon carbide via solution impregnation, the thermal conductivity of silicon carbide is significantly improved due to the modification of the inorganic salt and its mixing with modified expanded graphite, which reduces the supercooling of the inorganic salt. This improvement is mainly attributed to the introduction of a thermally conductive reinforcing phase into silicon carbide, ensuring a low contact thermal resistance between the thermally conductive reinforcing phase and the inorganic salt material. Simultaneously, the reduced silicon carbide particle size increases the heat transfer area between the thermally conductive reinforcing phase and the phase change material. Therefore, when inorganic salt-modified silicon carbide is mixed with other components, its thermal conductivity is improved, enhancing the material's heat storage performance. This material can absorb and release more latent heat during solid-liquid and liquid-solid phase transitions, thus achieving efficient heat storage and release.

[0031] The beneficial effects of this invention are:

[0032] The composite thermal storage material prepared by the present invention through the combination of heat-treated mullite powder modified by beeswax and coconut oil, expanded graphite modified by silk protein, silicon carbide modified by hydrated salt and sodium bentonite has excellent thermal storage properties and can maintain its good stability, thus exerting a long-term thermal storage effect. Detailed Implementation

[0033] To further illustrate the technical means and effects of the present invention in achieving its intended purpose, the following detailed description of the specific implementation methods, structures, features, and effects of the present invention, in conjunction with embodiments, is provided below.

[0034] In the following examples and comparative examples:

[0035] The preparation process of the silk fibroin aqueous solution is as follows: at 40℃, the silk fibroin is dissolved in 10mol / L LiBr solution, the resulting solution is poured into a cellulose dialysis bag with a flux of 12000, dialyzed with deionized water for 100h, and then prepared into a 5% silk fibroin aqueous solution.

[0036] Sodium-based bentonite: purchased from Wuhan Jiyesheng Chemical Co., Ltd., item number: A00355;

[0037] Expanded graphite: purchased from Wuhan Jiyesheng Chemical Co., Ltd., item number: A00375;

[0038] Silicon carbide: purchased from Condis Chemical (Hubei) Co., Ltd.;

[0039] Silk protein: purchased from Hubei Baidu Chemical Co., Ltd., product number: BD6242;

[0040] Disodium hydrogen phosphate dodecahydrate: purchased from Shanghai Aladdin Biochemical Technology Co., Ltd., product number: D431178;

[0041] Ammonium aluminum sulfate dodecahydrate: purchased from Shanghai Maclean Biochemical Technology Co., Ltd., product number: A800697;

[0042] Beeswax: Purchased from Shandong Xiya Chemical Co., Ltd., product number: 4701;

[0043] Coconut oil: purchased from Shanghai Haohong Biomedical Technology Co., Ltd., product number: 1268838;

[0044] Mullite powder: purchased from Lingshou County Fengju Mineral Products Processing Plant;

[0045] Hydroxyethyl cellulose: purchased from Shanghai Maclean Biochemical Technology Co., Ltd., product number: H960258;

[0046] Polyvinyl alcohol: purchased from Shanghai Maclean Biochemical Technology Co., Ltd., product number: P816865.

[0047] Example 1

[0048] Preparation of modified expanded graphite:

[0049] Expanded graphite was calcined at 650℃ for 1 hour, then heated to 720℃ and held for 1.5 hours before cooling to room temperature to obtain heat-treated expanded graphite. 20 parts of the heat-treated expanded graphite were added to 70 parts of a 3% (w / w) aqueous solution of silk protein, and stirred for 0.5 hours. Then, 2 parts of glutaraldehyde were added at 40℃, and the reaction was continued with stirring for 6 hours. After filtration and drying in a vacuum drying oven at 105℃, modified expanded graphite was obtained.

[0050] The preparation process of modified silicon carbide is as follows:

[0051] Disodium hydrogen phosphate dodecahydrate and ammonium aluminum sulfate dodecahydrate in a mass ratio of 1:1 were dissolved in water and ultrasonically dispersed. The uniformly dispersed solution was then heated to 105°C to completely evaporate the water. After drying, a solid material was obtained. The solid material was prepared into a saturated solution and dripped onto silicon carbide 5 times. Then the water was evaporated. Modified silicon carbide was obtained by filling the pores of silicon carbide with the solid material through solution impregnation.

[0052] S1. By mass, 10 parts of mullite powder are calcined in a muffle furnace for 4 hours at a temperature of 700°C and then cooled to room temperature.

[0053] S2. At 60℃, 10 parts of beeswax and coconut oil in a mass ratio of 1:1 are fully melted, and then 10 parts of mullite powder are added. The mixture is stirred at 500 r / min for 1 hour to obtain mullite powder uniformly loaded with beeswax.

[0054] S3. Mix 30 parts of modified expanded graphite, 10 parts of mullite powder uniformly loaded with beeswax, 2 parts of hydroxyethyl cellulose and 100 parts of water and stir at 500 r / min for 1 h, then sonicate for 3 h to obtain a suspension.

[0055] S4. The suspension is spray-dried to obtain a uniformly mixed first mixture, wherein the fan frequency of the spray dryer is 35.00 Hz, the inlet air temperature is 150 ℃, and the creeping speed is 2 RPM.

[0056] S5. Add 8 parts of sodium bentonite, 10 parts of modified silicon carbide and 3 parts of polyvinyl alcohol to the first mixture and mix evenly. Grind the mixture in a ball mill at 400 r / min for 3 hours, then knead it in a compounding extruder for 20 minutes. After aging for 17 hours, extrude it into shape.

[0057] The composite thermal storage material for building is prepared by holding the material at 130℃ for 2 hours in a reducing atmosphere and then naturally cooling it to room temperature.

[0058] Example 2

[0059] Preparation of modified expanded graphite:

[0060] Expanded graphite was calcined at 670℃ for 1 hour, then heated to 730℃ and held for 1.5 hours before cooling to room temperature to obtain heat-treated expanded graphite. 25 parts of the heat-treated expanded graphite were added to 80 parts of a 4% (w / w) aqueous solution of silk protein and stirred for 0.5 hours. Then, 3 parts of glutaraldehyde were added at 45℃ and the reaction was continued with stirring for 7 hours. After filtration and drying in a vacuum drying oven at 105℃, modified expanded graphite was obtained.

[0061] The preparation process of modified silicon carbide is as follows:

[0062] Disodium hydrogen phosphate dodecahydrate and ammonium aluminum sulfate dodecahydrate in a mass ratio of 1:1.3 were dissolved in water and ultrasonically dispersed. The uniformly dispersed solution was then heated to 107°C to completely evaporate the water. After drying, a solid material was obtained. The solid material was prepared into a saturated solution and dripped onto silicon carbide 7 times. Then the water was evaporated. Modified silicon carbide was obtained by filling the pores of silicon carbide with the solid material through solution impregnation.

[0063] S1. By mass, 13 parts of mullite powder were calcined in a muffle furnace for 4.5 hours at a temperature of 750°C and then cooled to room temperature.

[0064] S2. At 65℃, 13 parts by mass of beeswax and coconut oil were fully melted, and then 13 parts by mass of mullite powder were added. The mixture was stirred at 600 r / min for 1 hour. After thorough mixing, a uniformly beeswax-loaded mullite powder was obtained.

[0065] S3. Mix 37 parts of modified expanded graphite, 13 parts of mullite powder uniformly loaded with beeswax, 2.5 parts of hydroxyethyl cellulose and 105 parts of water and stir at 550 r / min for 1 h, then sonicate for 4 h to obtain a suspension.

[0066] S4. The suspension is spray-dried to obtain a uniformly mixed first mixture, wherein the fan frequency of the spray dryer is 35.00Hz, the inlet air temperature is 170℃, and the creeping speed is 3RPM.

[0067] S5. Add 11 parts of sodium bentonite, 12 parts of modified silicon carbide and 5 parts of polyvinyl alcohol to the first mixture and mix evenly. Grind the mixture in a ball mill at 400 r / min for 3 hours, then knead it in a compounding extruder for 20 minutes. After aging for 17 hours, extrude it into shape.

[0068] The composite thermal storage material for building is prepared by holding the material at 140℃ for 2 hours in a reducing atmosphere and then naturally cooling it to room temperature.

[0069] Example 3

[0070] Preparation of modified expanded graphite:

[0071] Expanded graphite was calcined at 700℃ for 1 hour, then heated to 750℃ and held for 1.5 hours before cooling to room temperature to obtain heat-treated expanded graphite. 30 parts of the heat-treated expanded graphite were added to 90 parts of a 5% (w / w) aqueous solution of silk protein and stirred for 0.5 hours. Then, 5 parts of glutaraldehyde were added at 50℃ and the reaction was continued with stirring for 8 hours. After filtration and drying in a vacuum drying oven at 105℃, modified expanded graphite was obtained.

[0072] The preparation process of modified silicon carbide is as follows:

[0073] Disodium hydrogen phosphate dodecahydrate and ammonium aluminum sulfate dodecahydrate in a mass ratio of 1:1.5 were dissolved in water and ultrasonically dispersed. The uniformly dispersed solution was then heated to 110°C to completely evaporate the water. After drying, a solid material was obtained. The solid material was prepared into a saturated solution and dripped onto silicon carbide 10 times. Then the water was evaporated. Modified silicon carbide was obtained by filling the pores of silicon carbide with the solid material through solution impregnation.

[0074] S1. By mass, 15 parts of mullite powder were calcined in a muffle furnace for 5 hours at a temperature of 800°C and then cooled to room temperature.

[0075] S2. At 70℃, 15 parts by mass of beeswax and coconut oil in a 1:1 ratio were fully melted, and then 15 parts of mullite powder were added. The mixture was stirred at 700 r / min for 1.5 h. After thorough mixing, a uniformly loaded mullite powder with beeswax was obtained.

[0076] S3. Mix 45 parts of modified expanded graphite, 15 parts of mullite powder uniformly loaded with beeswax, 3 parts of hydroxyethyl cellulose and 110 parts of water and stir at 600 r / min for 1 h, then sonicate for 5 h to obtain a suspension.

[0077] S4. The suspension is spray-dried to obtain a uniformly mixed first mixture, wherein the fan frequency of the spray dryer is 35.00 Hz, the inlet air temperature is 180 ℃, and the creeping speed is 5 RPM.

[0078] S5. Add 13 parts of sodium bentonite, 13 parts of modified silicon carbide and 7 parts of polyvinyl alcohol to the first mixture and mix evenly. Grind the mixture in a ball mill at 400 r / min for 3 hours, then knead it in a compounding extruder for 20 minutes. After aging for 17 hours, extrude it into shape.

[0079] The composite thermal storage material for building is prepared by holding the material at 150℃ for 2 hours in a reducing atmosphere and then naturally cooling it to room temperature.

[0080] Comparative Example 1

[0081] The difference between Comparative Example 1 and Example 1 is that the expanded graphite in Comparative Example 1 was not modified with silk protein, while the other operations were the same.

[0082] Comparative Example 2

[0083] The difference between Comparative Example 2 and Example 1 is that in Comparative Example 2, silicon carbide was modified by aluminum ammonium sulfate dodecahydrate, and no disodium hydrogen phosphate dodecahydrate was added; all other operations were the same.

[0084] Comparative Example 3

[0085] The difference between Comparative Example 3 and Example 1 is that the silicon carbide in Comparative Example 3 was not modified by inorganic salts, while the other operations were the same.

[0086] Comparative Example 4

[0087] The difference between Comparative Example 4 and Example 1 is that no coconut oil was added to the beeswax in Comparative Example 4, but all other operations were the same.

[0088] Comparative Example 5

[0089] The difference between Comparative Example 5 and Example 1 is that the mullite powder in Comparative Example 5 was not treated with beeswax and coconut oil, while the rest of the operations were the same.

[0090] Performance testing: Thermal conductivity was measured using a thermal conductivity meter, and the data is shown in the table below:

[0091]

[0092]

[0093] As can be seen from the above data, the composite thermal storage material for buildings prepared by this invention has high thermal storage density and thermal conductivity.

[0094] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A method for producing a building composite heat storage material, characterized by, Includes the following steps; S1. By mass, 10-15 parts of mullite powder are calcined in a muffle furnace for 4-5 hours at a temperature of 700-800℃, and then cooled to room temperature. S2. At 60-70℃, fully melt 10-15 parts of a mixture of beeswax and coconut oil, add 10-15 parts of mullite powder, and stir thoroughly to obtain mullite powder uniformly loaded with beeswax. S3. Mix 30-45 parts of modified expanded graphite, 10-15 parts of mullite powder uniformly loaded with beeswax, 2-3 parts of dispersant and 100-110 parts of water and stir for 1 hour, then treat with ultrasound for 3-5 hours to obtain a suspension. The specific preparation process of the modified expanded graphite is as follows: Expanded graphite was calcined at 650-700℃ for 1 hour, then heated to 720-750℃ and held for 1.5 hours before cooling to room temperature to obtain heat-treated expanded graphite. 20-30 parts of the heat-treated expanded graphite were added to 70-90 parts of a silk protein aqueous solution and stirred for 0.5 hours. Then, 2-5 parts of glutaraldehyde were added at 40-50℃ and the reaction was continued with stirring for 6-8 hours. After filtration and drying in a vacuum drying oven at 105℃, modified expanded graphite was obtained. S4. The suspension is spray-dried to obtain a homogeneous first mixture; S5. Continue to add 8-13 parts of sodium-based bentonite, 10-13 parts of modified silicon carbide and 3-7 parts of binder to the first mixture and mix evenly. Grind the mixture in a ball mill at 400 r / min for 3 hours, then knead it in a compounding extruder for 20 minutes, age it for 17 hours, and then extrude it into shape. The composite thermal storage material for buildings is prepared by holding the material at 130~150℃ for 2 hours in a reducing atmosphere and then naturally cooling it to room temperature.

2. The method of claim 1, wherein: In step S2, the mass ratio of beeswax to coconut oil is 1:

1.

3. The method for preparing composite thermal storage material for buildings according to claim 1, characterized in that: In step S2, the stirring speed is 500~700 r / min and the stirring time is 1~1.5h.

4. The method for preparing composite thermal storage material for buildings according to claim 1, characterized in that: In step S3, the dispersant is hydroxyethyl cellulose or hydroxymethyl cellulose.

5. The method for preparing composite thermal storage material for buildings according to claim 1, characterized in that: In step S3, the stirring speed is 500~600 r / min.

6. The method for preparing composite thermal storage material for buildings according to claim 1, characterized in that: In step S3, the preparation process of the silk fibroin aqueous solution is as follows: at 40°C, the silk fibroin is dissolved in 10 mol / L LiBr solution, the resulting solution is poured into a cellulose dialysis bag with a flux of 12000, dialyzed with deionized water for 100 h, and then prepared into a 5% silk fibroin aqueous solution.

7. The method for preparing composite thermal storage material for buildings according to claim 1, characterized in that: In step S4, during the spray drying process: the fan frequency of the spray dryer is 35.00 Hz, the inlet air temperature is 150~180℃, and the creeping speed is 2~5 RPM.

8. The method for preparing composite thermal storage material for buildings according to claim 1, characterized in that: In step S5, the specific preparation process of the modified silicon carbide is as follows: Disodium hydrogen phosphate dodecahydrate and ammonium aluminum sulfate dodecahydrate in a mass ratio of 1: (1~1.5) were dissolved in water and ultrasonically dispersed. The uniformly dispersed solution was then heated to 105~110℃ to completely evaporate the water. After drying, a solid material was obtained. The solid material was prepared into a saturated solution and silicon carbide was impregnated dropwise 5~10 times. Then the water was evaporated to obtain modified silicon carbide.

9. The method for preparing composite thermal storage material for buildings according to claim 1, characterized in that: In step S5, the binder is one of cellulose, polyvinyl alcohol, and clay.

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