Phase change energy storage concrete aggregate, its preparation method and application

Abstract

The present disclosure provides a phase change energy storage concrete aggregate, a preparation method thereof and an application thereof, belonging to the technical field of building materials. The phase change energy storage concrete aggregate includes: a first inner core, the first inner core including composite phase change material particles and a porous cement-based material; and a first shell layer formed on the outer surface of the first inner core, the first shell layer including a cement-based encapsulating material; wherein, the composite phase change material particles include: a second inner core, the second inner core including an inorganic hydrated salt phase change material and a porous medium material, the inorganic hydrated salt phase change material being loaded in the pores of the porous medium material; and a second shell layer formed on the outer surface of the second inner core, the second shell layer sequentially including a hydrophobic layer, a polymer layer and a hydrophilic layer from inside to outside. The present disclosure effectively blocks the dehydration channels of the inorganic hydrated salt phase change material by using a double-shell layer structure, and improves the thermal performance of the phase change energy storage concrete aggregate.

Description

Technical Field

[0001] The present disclosure relates to the technical field of building materials, and in particular to phase change energy storage concrete aggregates and their preparation methods and applications. Background Art

[0002] Buildings account for approximately 30% of global final energy consumption, including approximately 55% of global electricity consumption. Phase change materials utilize their extremely high latent heat storage and release capabilities during the solid-liquid phase change process. By adding phase change materials to improve the heat storage capacity of concrete, it helps to reduce indoor temperature fluctuations and loads, enhance building energy utilization efficiency, and reduce energy consumption and carbon emissions.

[0003] In related technologies, the preparation of phase change energy storage concrete mainly uses organic phase change materials. However, organic phase change materials have the disadvantages of low energy storage density, low thermal conductivity, flammability, and high cost, which are not conducive to large-scale application and promotion in the building field.

[0004] In the process of implementing the concept of the present disclosure, the inventors found that inorganic hydrated salts have advantages such as suitable phase change temperature, large heat storage density, cheap raw materials, and non-flammability, and are expected to become ideal heat storage materials in the building field. However, inorganic hydrated salt phase change materials have disadvantages such as poor chemical stability, which limits their application in the building field. Summary of the Invention

[0005] In view of this, in order to at least partially solve at least one of the above-mentioned technical problems, the present disclosure provides a phase change energy storage concrete aggregate and its preparation method and application.

[0006] According to an embodiment of one aspect of the present disclosure, there is provided a phase change energy storage concrete aggregate, comprising:

[0007] A first core, the first core includes composite phase change material particles and porous cement-based materials; and

[0008] A first shell layer, formed on the outer surface of the first core, the first shell layer includes a cement-based encapsulating material;

[0009] Wherein, the composite phase change material particles include:

[0010] A second core, the second core includes an inorganic hydrated salt phase change material and a porous medium material, and the inorganic hydrated salt phase change material is loaded in the pores of the porous medium material; and

[0011] A second shell layer, formed on the outer surface of the second core, the second shell layer includes a hydrophobic layer, a polymer layer, and a hydrophilic layer in sequence from the inside to the outside.

[0012] According to an embodiment of the present disclosure, the pore surface of the porous medium material is hydrophilically modified by grafting polyacrylamide.

[0013] According to an embodiment of the present disclosure, the above-mentioned inorganic hydrated salt phase change material includes an inorganic hydrated salt, a nucleating agent, and a nano-thermal conductivity enhancing material.

[0014] According to an embodiment of the present disclosure, the above-mentioned porous medium material includes mineral rock powder, preferably including one or more of the following mineral rock powders: expanded perlite, expanded vermiculite, diatomaceous earth, hollow glass, fly ash, ceramic microspheres.

[0015] According to an embodiment of the present disclosure, the phase change temperature of the above-mentioned inorganic hydrated salt phase change material is 18~35°C.

[0016] According to an embodiment of the present disclosure, the above-mentioned hydrophobic layer includes a cationic surfactant.

[0017] According to an embodiment of the present disclosure, the above-mentioned polymer layer includes a thermosetting resin.

[0018] According to an embodiment of the present disclosure, the above-mentioned hydrophilic layer includes one or more of nano-silica and fluorine-containing polymers.

[0019] According to an embodiment of the present disclosure, the above-mentioned porous cement-based material is formed by a cement admixture, and the cement admixture includes an air-entraining agent, portland cement, and ultrafine powder.

[0020] According to an embodiment of the present disclosure, the above-mentioned phase change energy storage concrete aggregate includes 20wt%~80wt% of the above-mentioned composite phase change material particles, 10wt%~50wt% of the above-mentioned porous cement-based material, and 10wt%~50wt% of the above-mentioned cement-based encapsulation material.

[0021] According to an embodiment of the present disclosure, the size of the above-mentioned phase change energy storage concrete aggregate is 0.5~30.0mm.

[0022] According to an embodiment of the present disclosure, the above-mentioned composite phase change material particles include 20wt%~60wt% of the above-mentioned inorganic hydrated salt phase change material, 10wt%~40wt% of the above-mentioned porous medium material, 5wt%~15wt% of the above-mentioned hydrophobic layer, 10wt%~30wt% of the above-mentioned polymer layer, and 5wt%~15wt% of the above-mentioned hydrophilic layer.

[0023] According to an embodiment of the present disclosure, the size of the above-mentioned composite phase change material particles is 0.1~1000μm.

[0024] According to an embodiment of another aspect of the present disclosure, there is provided a method for preparing the above-mentioned phase change energy storage concrete aggregate, including:

[0025] Adding the porous medium material to the molten inorganic hydrated salt phase change material, and performing vacuum impregnation to obtain a mixed phase change material;

[0026] The above-mentioned composite phase change material particles are obtained by successively performing hydrophobic treatment, polymer encapsulation, and hydrophilic treatment on the above-mentioned mixed phase change material;

[0027] The above-mentioned composite phase change material particles are mixed uniformly with a cementitious material in water and granulated to obtain phase change aggregates;

[0028] A cementitious material is sprayed on the surface of the above-mentioned phase change aggregates and left to stand and solidify to obtain the above-mentioned phase change energy storage concrete aggregates;

[0029] Among them, the above-mentioned cementitious material includes an air-entraining agent, cement, and ultrafine powder.

[0030] According to an embodiment of the present disclosure, the above-mentioned porous medium material is prepared by the following method: adding a porous medium raw material to a strong acid solution or a strong base solution for impregnation reaction to obtain an expanded porous medium raw material; dispersing the above-mentioned expanded porous medium raw material into an organic solvent, adding an ethanol solution containing a silane coupling agent, acrylamide monomer, and an initiator, and performing a polymerization reaction to obtain the above-mentioned porous medium material.

[0031] According to an embodiment of the present disclosure, the concentration of the above-mentioned strong acid solution or strong base solution is 0.5 - 5.0 mol / L.

[0032] According to an embodiment of the present disclosure, the pH of the above-mentioned ethanol solution containing a silane coupling agent is 4 - 7.

[0033] According to an embodiment of the present disclosure, the above-mentioned hydrophobic treatment includes: adding the above-mentioned mixed phase change material to a hydrophobic material solution, and successively performing stirring, freezing to a solid state, and physical crushing to obtain a hydrophobic-treated mixed phase change material.

[0034] According to an embodiment of the present disclosure, the above-mentioned polymer encapsulation includes: adding a mixture of an uncured resin and a curing agent to the above-mentioned hydrophobic-treated mixed phase change material and performing a curing reaction to obtain a polymer-encapsulated mixed phase change material.

[0035] According to an embodiment of the present disclosure, the above-mentioned hydrophilic treatment includes: spraying a hydrophilic material onto the above-mentioned polymer-encapsulated mixed phase change material to obtain the above-mentioned composite phase change material particles.

[0036] According to an embodiment of the present disclosure, the degree of vacuum of the above-mentioned vacuum impregnation is 0.02 - 0.08 MPa.

[0037] According to another embodiment of the present disclosure, there is provided a concrete including the above-mentioned phase change energy storage concrete aggregates or phase change energy storage concrete aggregates prepared by the above-mentioned preparation method.

[0038] According to an embodiment of the present disclosure, by loading an inorganic hydrated salt phase change material in the pores of a porous medium material, the adsorption capacity and stability of the inorganic hydrated salt phase change material are improved; through the first shell structure composed of a hydrophobic layer, a polymer layer, and a hydrophilic layer and the second shell structure composed of a cement-based encapsulation material, the compatibility between the interfaces of various materials is fully considered, and the dehydration channels of the inorganic hydrated salt phase change material are effectively blocked by using the double-shell structure, thereby improving the thermal performance of the phase change energy storage concrete aggregate. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Through the following description of the embodiments of the present disclosure with reference to the accompanying drawings, the above and other objects, features, and advantages of the present disclosure will become more apparent. In the drawings:

[0040] Figure 1 Schematically shows a structural diagram of a phase change energy storage concrete aggregate according to an embodiment of the present disclosure;

[0041] Wherein, 1-1 is a phase change composite material particle, 1-2 is a porous cement-based granulating material, and 1-3 is a cement-based encapsulation material;

[0042] Figure 2 Schematically shows a structural diagram of a composite phase change material particle according to an embodiment of the present disclosure;

[0043] Wherein, 2-1 is an inorganic hydrated salt phase change material, 2-2 is a porous medium material, 2-3 is a hydrophobic layer, 2-4 is a polymer layer, and 2-5 is a hydrophilic layer. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0044] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. However, it should be understood that these descriptions are merely exemplary and are not intended to limit the scope of the present disclosure. In the following detailed description, for the sake of explanation, many specific details are set forth to provide a comprehensive understanding of the embodiments of the present disclosure. However, it is obvious that one or more embodiments can also be implemented without these specific details. In addition, in the following description, descriptions of well-known structures and technologies are omitted to avoid unnecessarily confusing the concepts of the present disclosure.

[0045] The terms used herein are merely for describing specific embodiments and are not intended to limit the present disclosure. The term "including" used herein indicates the presence of features, steps, operations, but does not exclude the presence or addition of one or more other features.

[0046] In the case of using expressions such as "at least one of A, B, and C, etc.", generally, it should be interpreted according to the meaning that those skilled in the art usually understand this expression (for example, "a system having at least one of A, B, and C" should include, but not be limited to, a system having only A, only B, only C, having A and B, having A and C, having B and C, and / or having A, B, and C, etc.). In the case of using expressions such as "at least one of A, B, or C, etc.", generally, it should be interpreted according to the meaning that those skilled in the art usually understand this expression (for example, "a system having at least one of A, B, or C" should include, but not be limited to, a system having only A, only B, only C, having A and B, having A and C, having B and C, and / or having A, B, and C, etc.).

[0047] Inorganic hydrated salts have advantages such as suitable phase change temperature, large heat storage density, cheap raw materials, and non-flammability, and are expected to become ideal heat storage materials in the construction field. However, inorganic hydrated salt phase change materials have disadvantages such as poor chemical stability, which limits their application in the construction field. Therefore, improving the inherent defects of inorganic hydrated salts is a prerequisite for realizing their combination with the enclosure structure to achieve building energy conservation.

[0048] In the process of implementing the concept of the present disclosure, it is found that by introducing porous medium materials, the adsorption capacity and stability of inorganic hydrated salt phase change materials can be increased; through the design of a multi-layer shell structure, the dehydration channels of inorganic hydrated salt phase change materials can be effectively blocked, further improving the thermal performance of inorganic hydrated salt phase change materials.

[0049] Specifically, according to an embodiment of one aspect of the present disclosure, there is provided a phase change energy storage concrete aggregate, including:

[0050] A first inner core, the first inner core includes composite phase change material particles and porous cement-based materials; and

[0051] A first shell layer, formed on the outer surface of the first inner core, the first shell layer includes a cement-based encapsulating material;

[0052] Wherein, the composite phase change material particles include:

[0053] A second inner core, the second inner core includes an inorganic hydrated salt phase change material and a porous medium material, and the inorganic hydrated salt phase change material is loaded in the pores of the porous medium material; and

[0054] A second shell layer, formed on the outer surface of the second inner core, the second shell layer includes a hydrophobic layer, a polymer layer, and a hydrophilic layer in sequence from the inside to the outside.

[0055] Figure 1 Schematically shows a structural schematic diagram of the phase change energy storage concrete aggregate according to an embodiment of the present disclosure.

[0056] Among them, 1-1 is a composite phase change material particle; 1-2 is a porous cement-based material; 1-3 is a mesopore; 1-4 is a cement-based encapsulation material. The phase change composite material particle 1-1, the porous cement-based material 1-2 and the mesopore 1-3 form a first core, and the cement-based encapsulation material 1-4 forms a first shell layer.

[0057] Figure 2 Schematically shows a structural schematic diagram of a composite phase change material particle according to an embodiment of the present disclosure.

[0058] Among them, 2-1 is an inorganic hydrated salt phase change material; 2-2 is a porous medium material; 2-3 is a hydrophobic layer; 2-4 is a polymer layer; 2-5 is a hydrophilic layer. The inorganic hydrated salt phase change material 2-1 and the porous medium material 2-2 form a second core; the hydrophobic layer 2-3, the polymer layer 2-4 and the hydrophilic layer 2-5 form a second shell layer.

[0059] According to an embodiment of the present disclosure, the size of the porous medium material 2-2 can be in the micron scale or the nanometer scale. The present disclosure does not limit the size of the porous medium material 2-2, and any porous medium material 2-2 that can load the inorganic hydrated salt phase change material 2-1 is within the protection scope of the present disclosure.

[0060] According to an embodiment of the present disclosure, by loading the inorganic hydrated salt phase change material in the pores of the porous medium material, the adsorption amount and stability of the inorganic hydrated salt phase change material are improved; through the first shell layer structure composed of a hydrophobic layer, a polymer layer and a hydrophilic layer and the second shell layer structure composed of a cement-based encapsulation material, the compatibility between the interfaces of each material is fully considered, and the dehydration channel of the inorganic hydrated salt phase change material is effectively blocked by using the double shell layer structure, thereby improving the thermal performance of the phase change energy storage concrete aggregate.

[0061] According to an embodiment of the present disclosure, the pore surface of the porous medium material is hydrophilically modified by grafting polyacrylamide.

[0062] According to an embodiment of the present disclosure, before hydrophilically modifying (grafting polyacrylamide) the pore surface of the porous medium material 2-2, the porous medium material 2-2 can also be impregnated with a strong acid or a strong base for an impregnation reaction to expand and activate the pores of the porous medium material 2-2.

[0063] According to an embodiment of the present disclosure, by grafting polyacrylamide, the pore surface of the porous medium material 2-2 can be hydrophilically modified, further improving the adsorption amount and adsorption stability of the porous medium material 2-2 to the inorganic hydrated salt phase change material 2-1. Through the hydrophilic modification, the structural unit can contain an amide group, which is easy to form hydrogen bonds and has stronger hydrophilicity than the original hydroxyl group of the porous medium material.

[0064] According to an embodiment of the present disclosure, the acrylamide monomer can be grafted onto the surface of the porous carrier by a solution polymerization method through a silane coupling agent, and the acrylamide monomer can form linear polyacrylamide through free radical-initiated polymerization.

[0065] According to an embodiment of the present disclosure, the inorganic hydrated salt phase change material includes an inorganic hydrated salt, a nucleating agent, and a nano-thermal conductivity enhancing material.

[0066] According to an embodiment of the present disclosure, the inorganic hydrated salt can be a halide, nitrate, sulfate, phosphate, carbonate, acetate, etc. of alkali and alkaline earth metals. The present disclosure does not limit the specific type of the inorganic hydrated salt.

[0067] According to an embodiment of the present disclosure, the selection of the nucleating agent needs to match the inorganic hydrated salt. For example, for the inorganic hydrated salt based on calcium chloride hexahydrate, the nucleating agent can be strontium chloride hexahydrate, barium hydroxide, etc.; for sodium sulfate decahydrate, the nucleating agent can be borax, sodium silicate nonahydrate, etc.

[0068] The nano-thermal conductivity enhancing material can be nano-metal oxides, nano-metal materials, expanded graphene, carbon nanotubes, etc. Specifically, the nano-metal oxides can be nano-aluminum oxide, nano-titanium oxide, etc.; the nano-metal materials can be nano-silver, nano-copper, etc.

[0069] According to an embodiment of the present disclosure, by adding a nucleating agent to the inorganic hydrated salt, crystal growth sites can be provided for crystal growth, and the crystallization supercooling degree can be reduced; by adding a nano-thermal conductivity enhancing material, the thermal conductivity of the inorganic hydrated salt can be improved.

[0070] According to an embodiment of the present disclosure, the porous medium material 2-2 includes mineral rock powder, preferably including one or more of the following mineral rock powders: expanded perlite, expanded vermiculite, diatomite, hollow glass, fly ash, ceramic microspheres.

[0071] According to an embodiment of the present disclosure, the porous medium material 2-2 can be natural or artificial mineral rock powder, and the present disclosure does not limit this.

[0072] According to an embodiment of the present disclosure, the phase change temperature of the inorganic hydrated salt phase change material 2-1 is 18~35°C.

[0073] According to an embodiment of the present disclosure, the inorganic hydrated salt phase change material 2-1 can be applied to building envelopes. The phase change temperature of 18~35°C helps to reduce indoor temperature fluctuations and loads, improve the building energy utilization efficiency, and reduce energy consumption and carbon emissions.

[0074] According to an embodiment of the present disclosure, the hydrophobic layer 2-3 includes a cationic surfactant.

[0075] According to embodiments of the present disclosure, the cationic surfactant can be an amine salt type cationic surfactant, a quaternary ammonium salt type cationic surfactant, a heterocyclic type cationic surfactant, a pyridinium salt type cationic surfactant, etc. The present disclosure does not limit the specific types of the cationic surfactant.

[0076] According to embodiments of the present disclosure, the polymer layer 2-4 includes a thermosetting resin.

[0077] According to embodiments of the present disclosure, the thermosetting resin can be an epoxy resin, a polyester resin, a vinyl ester, a bismaleimide, a thermosetting polyimide, a cyanate ester, etc. The present disclosure does not limit the specific types of the thermosetting resin.

[0078] According to embodiments of the present disclosure, the hydrophilic layer 2-4 includes one or more of nano-silica, fluorides. Specifically, the hydrophilic layer 2-4 can include one or more of nano-silica, a fluorosilane hydrophilic coating, a fluorocarbon hydrophilic coating, etc.

[0079] According to embodiments of the present disclosure, the porous cement-based material 1-2 is formed of a cement admixture, and the cement admixture includes an air-entraining agent, a portland cement, and an ultrafine powder.

[0080] According to embodiments of the present disclosure, the air-entraining agent can include one or more of hydrophobic surface active substances such as sodium resinate, rosin heat polymer, etc.

[0081] According to embodiments of the present disclosure, the ultrafine powder can include one or more of fly ash, wollastonite powder, aerogel, titanium dioxide, etc.

[0082] According to embodiments of the present disclosure, the porous cement-based material 1-2 made of a cement admixture including an air-entraining agent, a portland cement, and an ultrafine powder can be used as a framework material for phase change energy storage concrete aggregates to improve the mechanical strength of the phase change energy storage concrete aggregates.

[0083] According to an embodiment of the present disclosure, the phase change energy storage concrete aggregate includes 20wt% - 80wt% of composite phase change material particles 1-1, 10wt% - 50wt% of porous cement-based material 1-2, and 10wt% - 50wt% of cement-based encapsulation material 1-4. Preferably, the phase change energy storage concrete aggregate includes 30wt% - 70wt% of composite phase change material particles 1-1, 10wt% - 40wt% of porous cement-based material 1-2, and 10wt% - 40wt% of cement-based encapsulation material 1-4. Further preferably, the phase change energy storage concrete aggregate includes 50wt% - 70wt% of composite phase change material particles 1-1, 20wt% - 30wt% of porous cement-based material 1-2, and 10wt% - 20wt% of cement-based encapsulation material 1-4. Specifically, the phase change energy storage concrete aggregate includes 60wt% of composite phase change material particles 1-1, 15wt% of porous cement-based material 1-2, and 25wt% of cement-based encapsulation material 1-4.

[0084] According to an embodiment of the present disclosure, the size of the phase change energy storage concrete aggregate is 0.5 - 30.0 mm, preferably 3 - 25 mm, and further preferably 10 - 20 mm. Specifically, the size of the phase change energy storage concrete aggregate can be 0.5 mm, 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 8 mm, 10 mm, 15 mm, 20 mm, 25 mm, or 30 mm.

[0085] According to an embodiment of the present disclosure, the composite phase change material particles 1-1 include 20wt% - 60wt% of inorganic hydrated salt phase change material 2-1, 10wt% - 40wt% of porous medium material 2-2, 5wt% - 15wt% of hydrophobic layer 2-3, 10wt% - 30wt% of polymer layer 2-4, and 5wt% - 15wt% of hydrophilic layer 2-4. Preferably, the composite phase change material particles 1-1 include 30wt% - 60wt% of inorganic hydrated salt phase change material 2-1, 15wt% - 40wt% of porous medium material 2-2, 5wt% - 15wt% of hydrophobic layer 2-3, 10wt% - 30wt% of polymer layer 2-4, and 5wt% - 15wt% of hydrophilic layer 2-4. Further preferably, the composite phase change material particles 1-1 include 40wt% - 55wt% of inorganic hydrated salt phase change material 2-1, 20wt% - 30wt% of porous medium material 2-2, 5wt% - 10wt% of hydrophobic layer 2-3, 10wt% - 20wt% of polymer layer 2-4, and 5wt% - 10wt% of hydrophilic layer 2-4. Specifically, the composite phase change material particles 1-1 include 50wt% of inorganic hydrated salt phase change material 2-1, 25wt% of porous medium material 2-2, 5% of hydrophobic layer 2-3, 15% of polymer layer 2-4, and 5% of hydrophilic layer 2-4.

[0086] According to an embodiment of the present disclosure, the size of the composite phase change material particles 1-1 is 0.1 to 1000 μm. Specifically, the size of the composite phase change material particles 1-1 is 0.1 μm, 1 μm, 5 μm, 10 μm, 50 μm, 100 μm, 300 μm, 500 μm, 700 μm or 1000 μm.

[0087] According to an embodiment of another aspect of the present disclosure, there is provided a method for preparing a phase change energy storage concrete aggregate, the preparation method comprising:

[0088] Adding a porous medium material to a molten inorganic hydrated salt phase change material, and performing vacuum impregnation to obtain a mixed phase change material;

[0089] Performing a hydrophobization treatment, a polymer encapsulation, and a hydrophilization treatment on the mixed phase change material in sequence to obtain composite phase change material particles;

[0090] Mixing the composite phase change material particles and a cement mixture uniformly in water, and performing granulation to obtain a phase change aggregate;

[0091] Spraying a cementitious material on the surface of the phase change aggregate, and performing static setting to obtain a phase change energy storage concrete aggregate;

[0092] wherein, the cement mixture includes an air-entraining agent, cement and ultrafine powder.

[0093] According to an embodiment of the present disclosure, through vacuum impregnation, the inorganic hydrated salt phase change material can be better loaded on the surface of the porous medium material; through hydrophobization treatment, polymer encapsulation, and hydrophilization treatment, the inorganic hydrated salt phase change material can be encapsulated with a first shell layer; by mixing and granulating the composite phase change material particles and the cement mixture, the composite phase change material particles and the porous cement-based material are made into a phase change aggregate, and the porous cement-based material can provide a support skeleton for the phase change energy storage concrete aggregate and improve the overall strength; finally, spraying a cementitious material on the surface of the phase change aggregate to form a cement-based encapsulating material on the surface and achieve a second shell layer encapsulation.

[0094] According to an embodiment of the present disclosure, the porous medium material is prepared by the following method:

[0095] Adding a porous medium raw material to a strong acid solution or a strong base solution for impregnation reaction to obtain an expanded porous medium raw material;

[0096] Dispersing the expanded porous medium raw material into an organic solvent, adding an ethanol solution containing a silane coupling agent, an acrylamide monomer and an initiator, and performing a polymerization reaction to obtain a porous medium material.

[0097] According to an embodiment of the present disclosure, the concentration of the strong acid solution or the strong base solution is 0.5 to 5.0 mol / L, preferably 0.5 to 4.0 mol / L, and more preferably 1 to 3 mol / L. Specifically, the concentration of the strong acid solution or the strong base solution is 0.5 mol / L, 1 mol / L, 2 mol / L, 3 mol / L, 4 mol / L or 5 mol / L.

[0098] According to an embodiment of the present disclosure, the strong acid solution may be one or more of a hydrochloric acid solution, a hydrobromic acid solution, a nitric acid solution or a sulfuric acid solution; the strong base solution may be one or more of a sodium hydroxide solution, a potassium hydroxide solution or a lithium hydroxide solution.

[0099] According to an embodiment of the present disclosure, the organic solvent may be one or more of absolute ethanol, methanol, ether, acetone, toluene, carbon tetrachloride.

[0100] According to an embodiment of the present disclosure, the pH of the ethanol solution containing the silane coupling agent is 4 to 7. Specifically, the pH of the ethanol solution containing the silane coupling agent may be 4.0, 5.0, 5.5, 6.0 or 7.0.

[0101] According to an embodiment of the present disclosure, the mass ratio between the inorganic hydrated salt phase change material and the porous medium material is (2 to 9):1.

[0102] According to an embodiment of the present disclosure, the hydrophobization treatment includes: adding the mixed phase change material into the hydrophobic material solution, and successively performing stirring, freezing to a solid state, and physical crushing to obtain the hydrophobized mixed phase change material.

[0103] According to an embodiment of the present disclosure, the hydrophobic material may include a cationic surfactant.

[0104] According to an embodiment of the present disclosure, the mass ratio between the added cationic surfactant and the mixed phase change material is (0.05 to 0.5):1.

[0105] According to an embodiment of the present disclosure, the polymer encapsulation includes: adding a mixture of an uncured resin and a curing agent into the hydrophobized mixed phase change material, and performing a curing reaction to obtain the polymer-encapsulated mixed phase change material.

[0106] According to an embodiment of the present disclosure, the uncured resin may be a reactive resin, and the reactive resin undergoes a curing reaction to obtain a thermosetting resin.

[0107] According to an embodiment of the present disclosure, the uncured resin may include an uncured thermosetting resin.

[0108] According to an embodiment of the present disclosure, the hydrophilization treatment includes: spraying a hydrophilic material onto the hybrid phase change material after polymer encapsulation to obtain composite phase change material particles.

[0109] According to an embodiment of the present disclosure, the hydrophilic material may include one or more of nano-silica and fluoride.

[0110] According to an embodiment of the present disclosure, the degree of vacuum for vacuum impregnation is 0.02 to 0.08 MPa, preferably 0.03 to 0.06 MPa. Specifically, the degree of vacuum for vacuum impregnation may be 0.02 MPa, 0.03 MPa, 0.04 MPa, 0.05 MPa, 0.06 MPa, 0.07 MPa, or 0.08 MPa.

[0111] According to an embodiment of still another aspect of the present disclosure, there is provided a concrete including the above-mentioned phase change energy storage concrete aggregate or the phase change energy storage concrete aggregate prepared by the above-mentioned preparation method.

[0112] According to an embodiment of the present disclosure, by adding the above-mentioned phase change energy storage concrete aggregate or the phase change energy storage concrete aggregate prepared by the above-mentioned preparation method into the concrete, the thermal performance and stability of the concrete can be improved.

[0113] The following lists a plurality of specific embodiments to illustrate the technical solutions of the present invention in detail. It should be noted that the specific embodiments below are only for illustration and do not limit the present invention.

[0114] Example 1

[0115] This embodiment provides a phase change energy storage concrete aggregate, including a first inner core, the first inner core includes 65 wt% of composite phase change material particles and 20 wt% of porous cement-based material; and a first shell layer, formed on the outer surface of the first inner core, the first shell layer includes 15 wt% of cement-based encapsulation material.

[0116] Among them, the composite phase change material particles include: a second inner core, the second inner core includes 40 wt% of inorganic hydrated salt phase change material and 35 wt% of porous medium material, and the inorganic hydrated salt phase change material is loaded in the pores of the porous medium material; and a second shell layer, formed on the outer surface of the second inner core, the second shell layer includes, from the inside to the outside, 5% of a hydrophobic layer, 15% of a polymer layer, and 5% of a hydrophilic layer.

[0117] The phase change energy storage concrete aggregate provided in this embodiment is prepared by the following method:

[0118] (1) Prepare a hybrid phase change material

[0119] The inorganic hydrated salt is selected as calcium chloride hexahydrate, and its phase change temperature range is 29 - 31 °C; expanded perlite powder with a particle size of about 200 mesh is selected as the porous medium raw material.

[0120] The inorganic hydrated salt phase change material is heated to the molten state at 50 °C, and the porous medium material is added. Under the conditions of 50 °C and a vacuum degree of 0.06 MPa, it is adsorbed and impregnated for 2 h to obtain the mixed phase change material.

[0121] The adsorption capacity leakage rate test is carried out on the above mixed phase change material. The adsorption capacity leakage rate test process is as follows: Take 10 g of the sample and place it on the filter paper. The ambient temperature is 20 °C to ensure that the sample remains in a solid state. Place the filter paper with the sample in the thermostatic oven, and set the temperature to 50 °C to completely change the inorganic hydrated salt material in the sample from the solid phase to the liquid phase. Then take out the filter paper from the thermostatic oven, observe the leakage trace, and measure the remaining weight of the sample. After testing, the loading amount of the inorganic hydrated salt phase change material is 50%wt of the weight of the mixed phase change material.

[0122] (2)The mixed phase change material is subjected to hydrophobic treatment, polymer encapsulation, and hydrophilic treatment in sequence to prepare composite phase change material particles

[0123] Dissolve the cationic surfactant cetyltrimethylammonium chloride in water, add it to the mixed phase change material and stir for 1 h, then place it in a low-temperature box and freeze it to a solid state, and physically crush it into powder.

[0124] Mix epoxy resin and curing agent in a ratio of 1:1, then add it to the above powder and cure it at room temperature for 24 h, and perform physical crushing.

[0125] Spray the nano-silica hydrophilic coating to obtain the composite phase change material particles with primary interface encapsulation.

[0126] (3)Mix the composite phase change material particles and the cement mixture, spray deionized water to mix evenly, and then place them in a granulator to roll or extrude into balls to form phase change aggregates, where the cement mixture includes an air-entraining agent, portland cement, and fly ash.

[0127] (4)Mix the portland cementitious material and water with a water-cement ratio of 0.35, spray it evenly on the surface of the phase change aggregates, and let it stand and solidify for three days to finally obtain the shaped composite phase change energy storage concrete aggregates with interface modification.

[0128] Example 2

[0129] This example provides a phase change energy storage concrete aggregate, including a first inner core, the first inner core includes 65 wt% of composite phase change material particles and 20 wt% of porous cement-based material; and a first shell layer, formed on the outer surface of the first inner core, the first shell layer includes 15 wt% of cement-based encapsulation material.

[0130] Among them, the composite phase change material particles include: a second inner core, the second inner core includes 55 wt% of inorganic hydrated salt phase change material and 20 wt% of porous medium material, and the inorganic hydrated salt phase change material is loaded in the pores of the porous medium material; and a second shell layer, formed on the outer surface of the second inner core, and the second shell layer sequentially includes a 5% hydrophobic layer, a 15% polymer layer and a 5% hydrophilic layer from the inside to the outside.

[0131] The phase change energy storage concrete aggregate provided by this embodiment is prepared by the following method:

[0132] (1) Prepare the porous medium material

[0133] Select expanded perlite powder of about 200 mesh as the porous medium raw material.

[0134] First, add deionized water to wash for 1 h and filter impurities; then add potassium hydroxide solution with a concentration of 5 mol / L, react for 2 h, and then filter and wash with deionized water until neutral; finally, put it in a drying oven and dry at 150 °C for 48 h to obtain the expanded perlite powder after pore expansion.

[0135] Adopt the solution polymerization method to graft acrylamide monomer onto the surface of the porous carrier through a silane coupling agent, and the acrylamide monomer undergoes free radical polymerization to form linear polyacrylamide. Specifically, add the silane coupling agent KH570 to an ethanol solution with a concentration of 95%, and adjust the solution to weakly acidic with glacial acetic acid, with a pH of 5, and stir at room temperature for 10 min until the solution is clear; then add it to the solution of the expanded perlite powder and anhydrous ethanol after dispersion, add acrylamide and potassium persulfate (initiator), stir in the reactor at 70 °C for 2 hours, and the product is obtained after filtration, washing and drying to obtain the hydrophilic modified expanded perlite powder.

[0136] (2) Prepare the mixed phase change material

[0137] The inorganic hydrated salt selects calcium chloride hexahydrate, and its phase change temperature range is 29 - 31 °C.

[0138] Heat the inorganic hydrated salt phase change material to the molten state at 50 °C, add the porous medium material, and adsorb and impregnate for 2 h at 50 °C and a vacuum degree of 0.06 MPa to obtain the mixed phase change material.

[0139] (3) Carry out hydrophobic treatment, polymer encapsulation and hydrophilic treatment on the mixed phase change material in sequence to prepare composite phase change material particles

[0140] Dissolve the cationic surfactant cetyltrimethylammonium chloride in water, add it to the shaped composite phase change material particles and stir for 1 h, then place it in a low-temperature box and freeze to solid state, and physically crush it into powder.

[0141] Mix epoxy resin and curing agent in a ratio of 1:1, then add it to the above powder, cure at room temperature for 24 h, and perform physical crushing.

[0142] Spray a nano-silica hydrophilic coating to obtain composite phase change material particles with a primary interface encapsulation.

[0143] (4)Mix the composite phase change material particles and cementitious materials, spray deionized water to mix evenly, and then place them in a granulator to roll or extrude into balls to form phase change aggregates, where the cementitious materials include an air-entraining agent, portland cement, and fly ash.

[0144] (5)Mix the portland cementitious material with water at a water-cement ratio of 0.35, spray it evenly on the surface of the phase change aggregates, and let it stand and solidify for three days to finally obtain shaped composite phase change energy storage concrete aggregates with interface modification.

[0145] Example 3

[0146] This example provides a phase change energy storage concrete aggregate, including a first inner core, the first inner core includes 65 wt% of composite phase change material particles and 20 wt% of porous cement-based material; and a first shell layer, formed on the outer surface of the first inner core, the first shell layer includes 15 wt% of cement-based encapsulation material.

[0147] Among them, the composite phase change material particles include: a second inner core, the second inner core includes 55 wt% of inorganic hydrated salt phase change material and 20 wt% of porous medium material, and the inorganic hydrated salt phase change material is loaded in the pores of the porous medium material; and a second shell layer, formed on the outer surface of the second inner core, the second shell layer includes 5% of a hydrophobic layer, 15% of a polymer layer, and 5% of a hydrophilic layer in sequence from the inside to the outside.

[0148] The phase change energy storage concrete aggregate provided in this example is prepared by the following method:

[0149] (1)Prepare inorganic hydrated salt phase change material

[0150] The inorganic hydrated salt selected is calcium chloride hexahydrate, and its phase change temperature range is 29 - 31 °C. Place calcium chloride hexahydrate in a beaker and heat it on a magnetic stirrer at 50 °C; add strontium chloride hexahydrate (nucleating agent) and nano-aluminum oxide (nano-thermal conductivity enhancing material) and stir for 30 minutes respectively to achieve the purpose of reducing supercooling and improving thermal conductivity.

[0151] (2)Prepare porous medium material

[0152] Select expanded perlite powder with a mesh size of about 200 as the raw material for the porous medium.

[0153] First, add deionized water and wash for 1 h, then filter out impurities. Next, add potassium hydroxide solution with a concentration of 5 mol / L and react for 2 h. Then, filter and wash with deionized water until neutral. Finally, place it in a drying oven and dry at 150 °C for 48 h to obtain the expanded perlite powder after pore expansion.

[0154] The acrylamide monomer is grafted onto the surface of the porous carrier through a silane coupling agent by solution polymerization method, and the acrylamide monomer forms linear polyacrylamide through free radical polymerization. Specifically, add the silane coupling agent KH570 into the ethanol solution with a concentration of 95%, and adjust the solution to weak acidity with glacial acetic acid, with a pH of 5. Stir at room temperature for 10 min until the solution is clear. Then add it to the solution of the expanded and pore-expanded perlite powder and absolute ethanol that have been dispersed well, add acrylamide and potassium persulfate (initiator), and stir in the reactor at 70 °C for 2 h. After the product is filtered, washed, and dried, the hydrophilic modified expanded perlite powder is obtained.

[0155] (3)Prepare the composite phase change material

[0156] Heat the prepared inorganic hydrated salt phase change material to the molten state at 50 °C, add the porous medium material, and adsorb and impregnate at 50 °C and a vacuum degree of 0.06 MPa for 2 h to obtain the composite phase change material.

[0157] According to the method provided in Example 1, test the adsorption capacity and leakage rate of the above composite phase change material. The loading amount of the inorganic hydrated salt phase change material is 73%wt of the weight of the composite phase change material.

[0158] (4)Carry out hydrophobic treatment, polymer encapsulation, and hydrophilic treatment on the composite phase change material in sequence to prepare composite phase change material particles

[0159] Dissolve the cationic surfactant cetyltrimethylammonium chloride in water, add it to the shaped composite phase change material particles and stir for 1 h, then place it in a low-temperature box and freeze to solid state, and physically crush it into powder.

[0160] Mix epoxy resin and curing agent in a ratio of 1:1, then add it to the above powder and cure at room temperature for 20 h, and carry out physical crushing.

[0161] Spray the nano-silica hydrophilic coating to obtain the composite phase change material particles with primary interface encapsulation.

[0162] (5)Mix the composite phase change material particles and the cement mixture, spray deionized water and mix evenly, then place it in a granulator and roll or extrude into balls to form phase change aggregates, where the cement mixture includes an air-entraining agent, Portland cement, and fly ash.

[0163] (6) Mix the portland cement binder with water at a water-cement ratio of 0.35, and evenly spray it on the surface of the phase change aggregate. After standing and solidifying for three days, the shaped composite phase change energy storage concrete aggregate with interface modification is finally obtained.

[0164] Example 4

[0165] The phase change energy storage concrete aggregate provided in this example includes a first inner core. The first inner core includes 40 wt% of composite phase change material particles and 40 wt% of porous cement-based material; and a first shell layer formed on the outer surface of the first inner core. The first shell layer includes 20 wt% of cement-based encapsulating material.

[0166] Among them, the composite phase change material particles include: a second inner core. The second inner core includes 40 wt% of inorganic hydrated salt phase change material and 40 wt% of porous medium material. The inorganic hydrated salt phase change material is loaded in the pores of the porous medium material; and a second shell layer formed on the outer surface of the second inner core. The second shell layer includes a 5% hydrophobic layer, a 10% polymer layer, and a 5% hydrophilic layer in sequence from the inside to the outside.

[0167] The phase change energy storage concrete aggregate provided in this example is prepared by the following method:

[0168] (1) Prepare the inorganic hydrated salt phase change material

[0169] The inorganic hydrated salt selects a binary eutectic salt of sodium sulfate decahydrate and disodium hydrogen phosphate dodecahydrate, with a mass mixing ratio of 68:32, and its phase change temperature range is 25-30°C. Place the sodium sulfate decahydrate in a beaker and heat it on a magnetic stirrer at 50°C; add 1 wt% borax (nucleating agent) and 5 wt% expanded graphite (thermal conductivity enhancing material) respectively and stir for 30 minutes to achieve the purpose of reducing supercooling and improving thermal conductivity.

[0170] (2) Prepare the porous medium material

[0171] Select diatomite powder with a mesh size of about 200 as the raw material of the porous medium.

[0172] First, add deionized water to wash for 1 h and filter impurities; then add a hydrochloric acid solution with a concentration of 2 mol / L and react for 2 h, and then filter and wash with deionized water until neutral; finally, put it in an oven and dry at 150°C for 48 h to obtain the expanded perlite powder with enlarged pores.

[0173] The acrylamide monomer was grafted onto the surface of the porous carrier by solution polymerization using a silane coupling agent, and the acrylamide monomer was polymerized by free radical initiation to form linear polyacrylamide. Specifically, the silane coupling agent KH570 was added to an ethanol solution with a concentration of 95%, and the solution was adjusted to weakly acidic with glacial acetic acid, with a pH of 6, and stirred at room temperature for 10 min until the solution became clear; then it was added to a solution of expanded perlite powder and absolute ethanol that had been dispersed well, acrylamide and potassium persulfate (initiator) were added, and it was stirred at 70 °C in a reactor for 2 hours. The product was obtained as hydrophilic modified expanded perlite powder after filtration, washing, and drying.

[0174] (3)Preparation of the composite phase change material

[0175] The prepared inorganic hydrated salt phase change material was heated to the molten state at 50 °C, porous medium material was added, and it was adsorbed and impregnated for 3 h at 50 °C and a vacuum degree of 0.04 MPa to obtain the composite phase change material.

[0176] (4)The composite phase change material was subjected to hydrophobic treatment, polymer encapsulation, and hydrophilic treatment in sequence to prepare composite phase change material particles

[0177] The cationic surfactant dodecyl dimethyl benzyl ammonium chloride was dissolved in water, added to the shaped composite phase change material particles and stirred for 1 h, then placed in a low-temperature box and frozen to a solid state, and physically crushed into powder.

[0178] The polyester resin and the curing agent were mixed in a ratio of 1:1, then added to the above powder and cured at room temperature for 24 h, and physically crushed.

[0179] A fluorosilane hydrophilic coating was sprayed to obtain composite phase change material particles with primary interfacial encapsulation.

[0180] (5)The composite phase change material particles and the cement mixed material were evenly mixed by spraying deionized water, and then placed in a granulator and rolled or extruded into balls to form phase change aggregates, where the cement mixed material included sodium oleate (air-entraining agent), portland cement, and wollastonite powder.

[0181] (6)The portland cementitious material was mixed with water at a water-cement ratio of 0.35, evenly sprayed on the surface of the phase change aggregates, and left to solidify for three days to finally obtain the shaped composite phase change energy storage concrete aggregates with interfacial modification.

[0182] Comparative Example 1

[0183] This comparative example provides a phase change energy storage concrete aggregate, including a core, the core including 65 wt% of composite phase change material particles and 20 wt% of a porous cement-based material; and a shell layer, formed on the outer surface of the first core, the shell layer including 15 wt% of a cement-based encapsulation material.

[0184] Among them, the composite phase change material particles are a mixture composed of 67 wt% of inorganic hydrated salt phase change material and 33 wt% of porous medium material.

[0185] The phase change energy storage concrete aggregate provided in this comparative example is prepared by the following method:

[0186] (1) Preparation of composite phase change material particles

[0187] The inorganic hydrated salt is selected as calcium chloride hexahydrate, and its phase change temperature range is 29 - 31 °C; expanded perlite powder with a mesh size of about 200 is selected as the porous medium raw material.

[0188] The inorganic hydrated salt phase change material is heated to the molten state at 50 °C, the porous medium material is added, and adsorption impregnation is carried out at 50 °C and a vacuum degree of 0.06 MPa for 2 h to obtain composite phase change material particles.

[0189] (2) The composite phase change material particles and cementitious materials are evenly mixed by spraying deionized water, and then placed in a granulator to be rolled or extruded into balls to form phase change aggregates, where the cementitious materials include an air-entraining agent, Portland cement, and fly ash.

[0190] (3) The Portland cementitious material is mixed with water at a water-cement ratio of 0.35, and evenly sprayed on the surface of the phase change aggregates. After standing and solidifying for three days, finally, the shaped composite phase change energy storage concrete aggregates with interface modification are obtained.

[0191] Comparative Example 2

[0192] This comparative example provides a phase change energy storage concrete aggregate, including composite phase change material particles.

[0193] Among them, the composite phase change material particles include: a second inner core, the second inner core includes 50 wt% of inorganic hydrated salt phase change material and 25 wt% of porous medium material, and the inorganic hydrated salt phase change material is loaded in the pores of the porous medium material; and a second shell layer, formed on the outer surface of the second inner core, and the second shell layer sequentially includes a 5% hydrophobic layer, a 15% polymer layer, and a 5% hydrophilic layer from the inside to the outside.

[0194] The phase change energy storage concrete aggregate provided in this example is prepared by the following method:

[0195] (1) Preparation of mixed phase change material

[0196] The inorganic hydrated salt is selected as calcium chloride hexahydrate, and its phase change temperature range is 29 - 31 °C; expanded perlite powder with a mesh size of about 200 is selected as the porous medium raw material.

[0197] The inorganic hydrated salt phase change material is heated to the molten state at 50 °C, the porous medium material is added, and adsorption impregnation is carried out at 50 °C and a vacuum degree of 0.06 MPa for 2 h to obtain the mixed phase change material.

[0198] (2) The mixed phase change material is subjected to hydrophobic treatment, polymer encapsulation and hydrophilic treatment in sequence to prepare the composite phase change material particles

[0199] The cationic surfactant cetyltrimethylammonium chloride is dissolved in water, added to the shaped composite phase change material particles and stirred for 1 h, then placed in a low-temperature box and frozen to the solid state, and physically crushed into powder.

[0200] Epoxy resin and curing agent are mixed in a ratio of 1:1, then added to the above powder and cured at room temperature for 24 h, and physical crushing is carried out.

[0201] Spraying a nano-silica hydrophilic coating to obtain the composite phase change material particles with primary interface encapsulation.

[0202] Comparative Example 3

[0203] This comparative example provides a phase change energy storage concrete aggregate, which includes 71 wt% of composite phase change material particles and 29 wt% of porous cement-based material.

[0204] Among them, the composite phase change material particles include: a second core, the second core includes 50 wt% of inorganic hydrated salt phase change material and 20 wt% of porous medium material, and the inorganic hydrated salt phase change material is loaded in the pores of the porous medium material; and a second shell layer, formed on the outer surface of the second core, and the second shell layer includes a 5% hydrophobic layer, a 15% polymer layer and a 5% hydrophilic layer in sequence from the inside to the outside.

[0205] The phase change energy storage concrete aggregate provided by this comparative example is prepared by the following method:

[0206] (1) Preparation of the mixed phase change material

[0207] The inorganic hydrated salt is selected as calcium chloride hexahydrate, and its phase change temperature range is 29 - 31 °C; expanded perlite powder with a particle size of about 200 mesh is selected as the porous medium raw material.

[0208] The inorganic hydrated salt phase change material is heated to the molten state at 50 °C, the porous medium material is added, and adsorption impregnation is carried out at 50 °C and a vacuum degree of 0.06 MPa for 2 h to obtain the mixed phase change material.

[0209] (2) The mixed phase change material is subjected to hydrophobic treatment, polymer encapsulation and hydrophilic treatment in sequence to prepare the composite phase change material particles

[0210] Dissolve the cationic surfactant cetyltrimethylammonium chloride in water, add it to the shaped composite phase change material particles, stir for 1 h, then place it in a low-temperature box and freeze it to a solid state, and physically crush it into powder.

[0211] Mix epoxy resin and curing agent in a ratio of 1:1, then add it to the above powder and cure at room temperature for 24 h, and perform physical crushing.

[0212] Spray a nano-silica hydrophilic coating to obtain composite phase change material particles with a primary interface encapsulation.

[0213] (3) Mix the composite phase change material particles and cementitious materials, spray deionized water and mix evenly, then place them in a granulator and roll or extrude them into balls to form phase change energy storage concrete aggregates, where the cementitious materials include an air-entraining agent, portland cement and fly ash.

[0214] Test examples

[0215] Detect the phase change energy storage concrete aggregates prepared in Examples 1-4 and Comparative Examples 1-3 above. The detection methods are as follows:

[0216] Supercooling degree test of phase change material: Take 20 g of phase change material and place it in a test tube, heat it to 50 °C with a water bath, put a K-type thermocouple in the center of the sample, and after it is completely melted, place it in a cold water bath at 5 °C to cool. Record the temperature change curve of the phase change material every 10 s, and calculate the supercooling degree ΔT according to the difference between the inflection point temperature of the platform cooling and the actual starting crystallization temperature.

[0217] Phase change enthalpy value test of phase change material: In the temperature range of 0-50 °C, take 5-10 mg of each sample, and use differential scanning calorimetry (DSC, Netzsch Germany) to analyze the thermal properties of the phase change material samples at a heating rate of 5 K / min under a nitrogen atmosphere.

[0218] Cyclic latent heat loss rate test of phase change material: Heat the phase change material to 50 °C (for 30 minutes), then use a temperature control instrument to cool it to 0 °C (for 30 minutes) and repeat the cycle 500 times, and test and calculate the latent heat loss rate through the above DSC enthalpy value test method.

[0219] Thermal conductivity test: The thermal conductivity is tested by the transient plane heat source method. Use a transient plane heat source thermal conductivity tester. Place the sample in a square test mold to make a test block, and at an ambient temperature of 20 °C, clamp the plane heat source probe between two samples for testing.

[0220] Mechanical property test: Phase change aggregate was used to replace traditional aggregate at a replacement rate of 80% to prepare phase change lightweight aggregate concrete. The concrete mix ratio is shown in Table 1. Concrete test blocks with dimensions of 100*100*100 mm were made and cured under standard conditions for 28 days. The compressive strength was tested using a compression testing machine.

[0221] Table 1

[0222]

[0223] The test results of the phase change energy storage concrete aggregates prepared in the above Examples 1 to 4 and Comparative Examples 1 to 3 are shown in detail in Table 2.

[0224] Table 2

[0225]

[0226] The specific embodiments described above further illustrate the purpose, technical solutions, and beneficial effects of the present disclosure. It should be understood that the above are only specific embodiments of the present disclosure and are not used to limit the present disclosure. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present disclosure shall be included within the protection scope of the present disclosure.

Claims

1. A phase change energy storage concrete aggregate, characterized in that, The phase change energy storage concrete aggregate includes: A first core, the first core including composite phase change material particles and a porous cement-based material; and A first shell layer formed on the outer surface of the first core, the first shell layer including a cement-based encapsulation material; Wherein, the composite phase change material particles include: A second core, the second core including an inorganic hydrated salt phase change material and a porous medium material, the inorganic hydrated salt phase change material being loaded in the pores of the porous medium material; and A second shell layer formed on the outer surface of the second core, the second shell layer sequentially including a hydrophobic layer, a polymer layer, and a hydrophilic layer from the inside to the outside; Wherein, the hydrophobic layer includes a cationic surfactant; The polymer layer includes a thermosetting resin; The hydrophilic layer includes one or more of nano-silica and fluoride; The phase change energy storage concrete aggregate includes 20wt% - 80wt% of the composite phase change material particles, 10wt% - 50wt% of the porous cement-based material, and 10wt% - 50wt% of the cement-based encapsulation material; the size of the phase change energy storage concrete aggregate is 0.5 - 30.0 mm; The composite phase change material particles include 20wt% - 60wt% of the inorganic hydrated salt phase change material, 10wt% - 40wt% of the porous medium material, 5wt% - 15wt% of the hydrophobic layer, 10wt% - 30wt% of the polymer layer, and 5wt% - 15wt% of the hydrophilic layer; the size of the composite phase change material particles is 0.1 - 1000 μm.

2. The phase change energy storage concrete aggregate according to claim 1, wherein The pore surface of the porous medium material is hydrophilically modified by grafting polyacrylamide; The inorganic hydrated salt phase change material includes an inorganic hydrated salt, a nucleating agent, and a nano-thermal conductivity enhancing material.

3. The phase change energy storage concrete aggregate according to claim 1 or 2, wherein The porous medium material includes mineral rock powder, preferably including one or more of the following mineral rock powders: expanded perlite, expanded vermiculite, diatomite, hollow glass, fly ash, ceramic microspheres; The phase change temperature of the inorganic hydrated salt phase change material is 18 - 35 °C.

4. The phase change energy storage concrete aggregate according to claim 1 or 2, characterized in that, The porous cement-based material is formed from a cement mixture, and the cement mixture includes an air-entraining agent, Portland cement, and ultrafine powder.

5. A preparation method of the phase change energy storage concrete aggregate according to any one of claims 1 to 4, characterized in that, The preparation method includes: Adding the porous medium material to the molten inorganic hydrated salt phase change material, performing vacuum impregnation to obtain a mixed phase change material; Performing hydrophobic treatment, polymer encapsulation, and hydrophilic treatment on the mixed phase change material in sequence to obtain composite phase change material particles; Mixing the composite phase change material particles with the cement mixture evenly in water, and granulating to obtain phase change aggregates; Spraying a cementitious material on the surface of the phase change aggregates, and standing for solidification to obtain the phase change energy storage concrete aggregate; Wherein, the cement mixture includes an air-entraining agent, cement, and ultrafine powder.

6. The preparation method of the phase change energy storage concrete aggregate according to claim 5, characterized in that, The porous medium material is obtained by the following method: Adding the porous medium raw material to a strong acid solution or a strong base solution for impregnation reaction to obtain the porous medium raw material with enlarged pores; Disperse the porous medium raw material after reaming into an organic solvent, add an ethanol solution containing a silane coupling agent, acrylamide monomers and an initiator, and carry out a polymerization reaction to obtain the porous medium material.

7. The preparation method of the phase change energy storage concrete aggregate according to claim 6, characterized in that The concentration of the strong acid solution or strong base solution is 0.5 - 5.0 mol / L; The pH of the ethanol solution containing the silane coupling agent is 4 - 7.

8. The preparation method of the phase change energy storage concrete aggregate according to any one of claims 5 to 7, characterized in that, The hydrophobic treatment includes: Add the mixed phase change material into a hydrophobic material solution, and successively carry out stirring, freezing to a solid state, and physical crushing to obtain the hydrophobic-treated mixed phase change material; The polymer encapsulation includes: Add a mixture of uncured resin and a curing agent into the hydrophobic-treated mixed phase change material, and carry out a curing reaction to obtain the polymer-encapsulated mixed phase change material; The hydrophilic treatment includes: Spray a hydrophilic material onto the polymer-encapsulated mixed phase change material to obtain the composite phase change material particles; The degree of vacuum for the vacuum impregnation is 0.02 - 0.08 MPa.

9. A concrete, comprising the phase change energy storage concrete aggregate according to any one of claims 1 - 4 or the phase change energy storage concrete aggregate prepared by the preparation method according to any one of claims 5 - 8.

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