A PCM-based energy storage building material and its preparation method

Abstract

The present invention relates to a PCM-based energy storage building material and a preparation method thereof, belonging to the technical field of building materials. The energy storage building material comprises, by weight, 55-70 parts of ordinary Portland cement, 10-20 parts of aluminate cement, 10-15 parts of gypsum, 140-170 parts of fine aggregate, 15-25 parts of mineral powder, 18-26 parts of paraffin microcapsules, 5-7 parts of redispersible rubber powder, 0.8-1 parts of a water reducer, and 75-83 parts of water. The paraffin microcapsules are coated by in-situ crosslinking, making the encapsulated structure more stable. The calcium thioacetate on the surface of the paraffin microcapsules promotes the formation of a hydrated gel in the building material. The fully hydrated gel layer near the surface is strong, providing structural support for the paraffin microcapsules, further maintaining the stability of the capsule structure, making it less likely to leak during use and providing stable energy storage.

Description

Technical Field

[0001] The present invention belongs to the technical field of building materials, and in particular, relates to a PCM-based energy storage building material and a preparation method thereof. Background Art

[0002] With the continuous growth of energy demand and the increasing impact of energy consumption on the environment, energy conservation and emission reduction have become critical issues that must be urgently addressed in today's society. In the construction sector, traditional building materials, due to their high thermal conductivity and low thermal inertia, lead to large fluctuations in indoor temperature and low energy efficiency. Phase change materials (PCMs), as a new energy-saving material, can regulate the internal temperature of buildings by utilizing the latent heat released or absorbed during temperature changes. This reduces reliance on traditional heating and air conditioning systems, reduces energy consumption, and improves the energy efficiency of buildings.

[0003] In early studies, direct mixing was often used to combine PCM with a matrix. This means that PCM was directly combined with building materials such as cement, gypsum, and concrete without encapsulation. This method is simple and direct and has a high PCM loading capacity. However, during the energy storage process, PCM cyclically transforms between the liquid and solid phases, and PCM is easily lost, resulting in deterioration of heat storage performance. The emulsification microencapsulation method is used to encapsulate PCM in a polymer shell, which can effectively alleviate the leakage problem of PCM. However, in actual application, it is difficult for the polymer to form a stable and uniform cross-linked layer on the PCM surface. During the mixing and curing process of cement composite building materials, the shell is easily damaged. The phase change process is accompanied by contraction and expansion, which is prone to leakage, seriously affecting the energy storage effect. Summary of the Invention

[0004] In order to solve the technical problems mentioned in the background technology, the purpose of the present invention is to provide a PCM-based energy storage building material and a preparation method thereof.

[0005] The purpose of the present invention can be achieved through the following technical solutions:

[0006] A PCM-based energy storage building material comprises the following raw materials in parts by weight:

[0007] 55-70 parts of ordinary Portland cement, 10-20 parts of aluminate cement, 10-15 parts of gypsum, 140-170 parts of fine aggregate, 15-25 parts of mineral powder, 18-26 parts of paraffin microcapsules, 5-7 parts of redispersible rubber powder, 0.8-1 part of water reducer and 75-83 parts of water.

[0008] Paraffin microcapsules were prepared by the following method:

[0009] Step A1: Premix pentamethylene glycol, triethylamine, and anhydrous tetrahydrofuran, dry under nitrogen protection, and control the temperature in a water bath at 10-20°C. Slowly add methylvinyldichlorosilane and stir to react for 1.5-2 hours. Then add propylene diamine, raise the temperature to 45-55°C, and stir to react for 30-40 minutes. After the reaction, remove tetrahydrofuran by rotary evaporation to obtain an intermediate;

[0010] Furthermore, the feed ratio of methylvinyldichlorosilane, pentamethylene glycol, propylene diamine, triethylamine and anhydrous tetrahydrofuran is 0.1 mol: 80-90 mmol: 15-30 mmol: 6-10 mL: 45-55 mL, methylvinyldichlorosilane and pentamethylene glycol are substituted to form an oligomer with an alkyl chain block, and then amino group end-capping is introduced by active propylene diamine.

[0011] Step A2: Mix the intermediate, thioglycolic acid, photoinitiator and acetone, protect with nitrogen, and apply 150-200W / m 2 UV irradiation, stirring and reacting for 5-7 hours, after the reaction is completed, acetone is evaporated under reduced pressure to obtain a modifier;

[0012] Furthermore, the feed ratio of the intermediate, thioglycolic acid, photoinitiator and acetone is 10g:35-50mmol:10-15mg:40-50mL, and under ultraviolet initiation, thioglycolic acid and the double bond of the intermediate molecular side chain are click-added.

[0013] Step A3: preheating the paraffin wax and the modifier to dissolve them, adding deionized water for shear dispersion, controlling the temperature of the water bath at 50-60°C, applying stirring at 180-240 rpm, slowly adding isophorone diisocyanate and reacting for 1-1.5 hours, then adding calcium oxide and continuing stirring for 2-3 hours. After the reaction is completed, cooling and filtering to remove the aqueous phase, the substrate is washed with water and then vacuum dried to obtain paraffin microcapsules;

[0014] Furthermore, the feed ratio of paraffin, modifier, isophorone diisocyanate, calcium oxide and deionized water is 50g:4.5-6g:2.2-2.8g:12-16g:130-160mL, the modifier is attached to the surface of the paraffin emulsion droplets, its terminal amino group is cross-linked with isophorone diisocyanate to coat the paraffin, and the carboxylic acid structure of its molecular side chain reacts with calcium oxide to form calcium carboxylate for surface modification.

[0015] Preferably, the fine aggregate is machine-made sand with a fineness modulus of 1.7-2.5, which has a good flow and filling effect after compounding.

[0016] Preferably, the mineral powder is a mixture of limestone powder and fly ash, has good reactivity, and can fully participate in hydration on the surface of the paraffin microcapsules in the early stage to form a dense gel layer.

[0017] Preferably, the water reducing agent is selected from polycarboxylic acid water reducing agent, which has a high efficiency water reducing effect, maintains the fluidity of the composite mortar, and is conducive to the dispersion of paraffin microcapsules.

[0018] A method for preparing a PCM-based energy storage building material comprises: premixing ordinary Portland cement, aluminate cement, gypsum, mineral powder, paraffin microcapsules, and redispersible rubber powder; adding fine aggregate and mixing uniformly; dispersing a water reducer in water and then adding the mixture and mixing uniformly to obtain the PCM-based energy storage building material.

[0019] Beneficial effects of the present invention:

[0020] The present invention is based on a paraffin phase change energy storage material and maintains excellent energy storage stability in a cement mortar system through a modified encapsulation process. The paraffin microcapsules are substituted by methylvinyldichlorosilane and pentamethylene glycol to form an alkyl chain block oligomer, and then amino groups are introduced by active propylene diamine to form an intermediate. Then, a double bond click addition of thioglycolic acid and the side chain of the intermediate molecule is performed to introduce a side chain thioacetic acid structure to prepare a modifier. The paraffin is then coated by cross-linking the modifier with isophorone diisocyanate. The thioacetic acid structure on the side chain of the modifier molecule is neutralized with calcium oxide, and calcium acetate is introduced to modify the surface of the coating layer. Compared with the traditional external emulsion Compared with the chemical encapsulation technology, the main chain of the modifier contains a large number of alkyl chain blocks, which has good affinity with paraffin. The thioacetic acid structure of the side chain has high polarity and is easy to adhere to the surface of the paraffin droplets during shear dispersion. The terminal active amino group is cross-linked with isophorone diisocyanate to form an in-situ coating on the paraffin, and the encapsulated structure formed is more stable. The calcium thioacetate on the surface of the paraffin microcapsule promotes the formation of hydrated gel in the building material. The fully hydrated gel layer near the surface has high strength, which forms a structural support for the paraffin microcapsule, further maintaining the stability of the capsule structure, making it less likely to leak during use and playing a stable energy storage role. DETAILED DESCRIPTION

[0021] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0022] Example 1: Preparation of PCM-based energy storage building materials, specifically as follows:

[0023] (1) Preparation of paraffin microcapsules

[0024] Step A1: Pre-mix pentamethylene glycol, triethylamine, and anhydrous tetrahydrofuran, introduce dry nitrogen protection, control the water bath temperature at 10°C, control the stirring rate at 30 rpm, slowly add methylvinyldichlorosilane and stir to react for 2 hours, then add propylene diamine and mix, raise the temperature to 45°C, increase the stirring rate to 90 rpm, and stir to react for 40 minutes, wherein the feed ratio of methylvinyldichlorosilane, pentamethylene glycol, propylene diamine, triethylamine, and anhydrous tetrahydrofuran is 0.1 mol: 90 mmol: 15 mmol: 6 mL: 45 mL. After the reaction, remove tetrahydrofuran by rotary evaporation to obtain an intermediate.

[0025] Step A2: Take the intermediate, thioglycolic acid, photoinitiator and acetone, mix them, pass nitrogen protection, apply 150W / m 2 The reaction was carried out under ultraviolet irradiation and stirred at 120 rpm for 7 hours, wherein the photoinitiator was photoinitiator 1173, and the feed ratio of the intermediate, thioglycolic acid, photoinitiator and acetone was 10 g:35 mmol:10 mg:40 mL. After the reaction was completed, the acetone was evaporated under reduced pressure to obtain a modifier.

[0026] Step A3: preheat paraffin and modifier to 40°C for miscibility, add deionized water and shear and disperse at 1200 rpm for 5 minutes, control the water bath temperature to 50°C, apply stirring at 180 rpm, slowly add isophorone diisocyanate and react for 1.5 hours, then add calcium oxide and continue stirring for 3 hours, wherein the feed ratio of paraffin, modifier, isophorone diisocyanate, calcium oxide and deionized water is 50g:4.5g:2.2g:12g:130mL. After the reaction is completed, cool and filter to remove the aqueous phase, wash the substrate with water and vacuum dry to obtain paraffin microcapsules.

[0027] (2) Preparation of PCM-based energy storage building materials

[0028] Ingredients are prepared in parts by weight: 70 parts of ordinary Portland cement, using P.O42.5 type cement raw material; 10 parts of aluminate cement, using A600 type cement raw material; 10 parts of gypsum, industrial-grade building gypsum raw material; 170 parts of fine aggregate, compounded by machine-made sand with fineness moduli of 1.7, 1.9, 2.2 and 2.5 in a weight ratio of 1:2:2:1; 25 parts of mineral powder, using industrial-grade limestone powder and fly ash in a weight ratio of 2:1; 18 parts of paraffin microcapsules, prepared in this embodiment; 7 parts of redispersible rubber powder, using VINNAPAS®5044N type raw material; 1 part of water reducer, using GK-3000 type polycarboxylate water reducer; and 83 parts of water.

[0029] Blending: Add ordinary Portland cement, aluminate cement, gypsum, mineral powder, paraffin microcapsules and redispersible rubber powder into a blender and stir at 30 rpm for 10 minutes. Disperse the water reducer into water and then add it to the mixture to mix well to obtain PCM-based energy storage building materials.

[0030] Example 2: Preparation of PCM-based energy storage building materials, specifically as follows:

[0031] (1) Preparation of paraffin microcapsules

[0032] Step A1: Pre-mix pentamethylene glycol, triethylamine, and anhydrous tetrahydrofuran, introduce dry nitrogen protection, control the water bath temperature at 20°C, control the stirring rate at 50 rpm, slowly add methylvinyldichlorosilane and stir to react for 1.5 hours, then add propylene diamine and mix, raise the temperature to 55°C, increase the stirring rate to 120 rpm, and stir to react for 30 minutes, wherein the feed ratio of methylvinyldichlorosilane, pentamethylene glycol, propylene diamine, triethylamine, and anhydrous tetrahydrofuran is 0.1 mol: 80 mmol: 30 mmol: 10 mL: 55 mL. After the reaction, remove tetrahydrofuran by rotary evaporation to obtain an intermediate.

[0033] Step A2: Take the intermediate, thioglycolic acid, photoinitiator and acetone, mix them, pass nitrogen protection, apply 200W / m 2 The reaction was carried out under ultraviolet irradiation and stirred at 150 rpm for 5 hours, wherein the photoinitiator was photoinitiator 1173, and the feed ratio of the intermediate, thioglycolic acid, photoinitiator and acetone was 10 g:50 mmol:15 mg:50 mL. After the reaction was completed, the acetone was evaporated under reduced pressure to obtain a modifier.

[0034] Step A3: paraffin wax and modifier are preheated to 40°C for miscibility, deionized water is added and sheared and dispersed at 1200 rpm for 5 minutes, the water bath temperature is controlled at 60°C, stirring is applied at 240 rpm, isophorone diisocyanate is slowly added and reacted for 1 hour, and calcium oxide is added and stirring is continued for 2 hours. The feed ratio of paraffin wax, modifier, isophorone diisocyanate, calcium oxide and deionized water is 50g:6g:2.8g:16g:160mL. After the reaction is completed, the mixture is cooled and filtered to remove the aqueous phase. The substrate is washed with water and then vacuum dried to obtain paraffin microcapsules.

[0035] (2) Preparation of PCM-based energy storage building materials

[0036] Ingredients are prepared in parts by weight: 55 parts of ordinary Portland cement, using P.O42.5 type cement raw material; 20 parts of aluminate cement, using A600 type cement raw material; 15 parts of gypsum, industrial-grade building gypsum raw material; 140 parts of fine aggregate, compounded by machine-made sand with fineness moduli of 1.7, 1.9, 2.2 and 2.5 in a weight ratio of 1:2:2:1; 15 parts of mineral powder, using industrial-grade limestone powder and fly ash in a weight ratio of 2:1; 26 parts of paraffin microcapsules, prepared in this embodiment; 5 parts of redispersible rubber powder, using VINNAPAS®5044N type raw material; 0.8 parts of water reducer, using GK-3000 type polycarboxylate water reducer; and 75 parts of water.

[0037] Blending: Add ordinary Portland cement, aluminate cement, gypsum, mineral powder, paraffin microcapsules and redispersible rubber powder into a blender and stir at 30 rpm for 10 minutes. Disperse the water reducer into water and then add it to the mixture to mix well to obtain PCM-based energy storage building materials.

[0038] Example 3: Preparation of PCM-based energy storage building materials, as follows:

[0039] (1) Preparation of paraffin microcapsules

[0040] Step A1: Pre-mix pentamethylene glycol, triethylamine, and anhydrous tetrahydrofuran, introduce dry nitrogen protection, control the water bath temperature at 15°C, control the stirring rate at 50 rpm, slowly add methylvinyldichlorosilane and stir to react for 1.7 hours, then add propylene diamine and mix, raise the temperature to 50°C, increase the stirring rate to 120 rpm, and stir to react for 35 minutes, wherein the feed ratio of methylvinyldichlorosilane, pentamethylene glycol, propylene diamine, triethylamine, and anhydrous tetrahydrofuran is 0.1 mol: 85 mmol: 20 mmol: 8 mL: 50 mL. After the reaction, remove tetrahydrofuran by rotary evaporation to obtain an intermediate.

[0041] Step A2: Take the intermediate, thioglycolic acid, photoinitiator and acetone, mix them, pass nitrogen protection, apply 180W / m at room temperature 2 The reaction was carried out under ultraviolet irradiation and stirred at 150 rpm for 6 hours, wherein the photoinitiator was photoinitiator 1173, and the feed ratio of the intermediate, thioglycolic acid, photoinitiator and acetone was 10 g:45 mmol:12 mg:45 mL. After the reaction was completed, the acetone was evaporated under reduced pressure to obtain a modifier.

[0042] Step A3: paraffin wax and modifier were preheated to 40°C for miscibility, deionized water was added and sheared and dispersed at 1200 rpm for 5 minutes, the water bath temperature was controlled at 55°C, stirring was applied at 240 rpm, isophorone diisocyanate was slowly added and reacted for 1.2 hours, and calcium oxide was added and stirring was continued for 2.5 hours. The feed ratio of paraffin wax, modifier, isophorone diisocyanate, calcium oxide and deionized water was 50 g:5.5 g:2.5 g:14 g:150 mL. After the reaction was completed, the mixture was cooled and filtered to remove the aqueous phase. The substrate was washed with water and then vacuum dried to obtain paraffin microcapsules.

[0043] (2) Preparation of PCM-based energy storage building materials

[0044] Ingredients are prepared in parts by weight: 65 parts of ordinary Portland cement, using P.O42.5 type cement raw material; 12 parts of aluminate cement, using A600 type cement raw material; 13 parts of gypsum, industrial-grade building gypsum raw material; 160 parts of fine aggregate, compounded by machine-made sand with fineness moduli of 1.7, 1.9, 2.2 and 2.5 in a weight ratio of 1:2:2:1; 22 parts of mineral powder, using industrial-grade limestone powder and fly ash in a weight ratio of 2:1; 22 parts of paraffin microcapsules, prepared in this embodiment; 6 parts of redispersible rubber powder, using VINNAPAS®5044N type raw material; 0.8 parts of water reducer, using GK-3000 type polycarboxylate water reducer; and 80 parts of water.

[0045] Blending: Add ordinary Portland cement, aluminate cement, gypsum, mineral powder, paraffin microcapsules and redispersible rubber powder into a blender and stir at 30 rpm for 10 minutes. Disperse the water reducer into water and then add it to the mixture to mix well to obtain PCM-based energy storage building materials.

[0046] Example 4: Preparation of PCM-based energy storage building materials, specifically as follows:

[0047] (1) Preparation of paraffin microcapsules

[0048] Step A1: Pre-mix pentamethylene glycol, triethylamine, and anhydrous tetrahydrofuran, introduce dry nitrogen protection, control the water bath temperature at 20°C, control the stirring rate at 50 rpm, slowly add methylvinyldichlorosilane and stir to react for 1.7 hours, then add propylene diamine and mix, raise the temperature to 45°C, increase the stirring rate to 120 rpm, and stir to react for 35 minutes, wherein the feed ratio of methylvinyldichlorosilane, pentamethylene glycol, propylene diamine, triethylamine, and anhydrous tetrahydrofuran is 0.1 mol: 90 mmol: 20 mmol: 8 mL: 50 mL. After the reaction, remove tetrahydrofuran by rotary evaporation to obtain an intermediate.

[0049] Step A2: Take the intermediate, thioglycolic acid, photoinitiator and acetone, mix them, pass nitrogen protection, apply 200W / m 2 The reaction was carried out under ultraviolet irradiation and stirred at 150 rpm for 6 hours, wherein the photoinitiator was photoinitiator 1173, and the feed ratio of the intermediate, thioglycolic acid, photoinitiator and acetone was 10 g:40 mmol:10 mg:45 mL. After the reaction was completed, the acetone was evaporated under reduced pressure to obtain a modifier.

[0050] Step A3: paraffin wax and modifier are preheated to 40°C for miscibility, deionized water is added and sheared and dispersed at 1200 rpm for 5 minutes, the water bath temperature is controlled at 50°C, stirring is applied at 240 rpm, isophorone diisocyanate is slowly added and reacted for 1.2 hours, and calcium oxide is added and stirring is continued for 3 hours. The feed ratio of paraffin wax, modifier, isophorone diisocyanate, calcium oxide and deionized water is 50g:5g:2.4g:15g:150mL. After the reaction is completed, the mixture is cooled and filtered to remove the aqueous phase. The substrate is washed with water and then vacuum dried to obtain paraffin microcapsules.

[0051] (2) Preparation of PCM-based energy storage building materials

[0052] Ingredients are prepared in parts by weight: 60 parts of ordinary Portland cement, using P.O42.5 type cement raw material; 18 parts of aluminate cement, using A600 type cement raw material; 12 parts of gypsum, industrial-grade building gypsum raw material; 155 parts of fine aggregate, compounded by machine-made sand with fineness moduli of 1.7, 1.9, 2.2 and 2.5 in a weight ratio of 1:2:2:1; 20 parts of mineral powder, using industrial-grade limestone powder and fly ash in a weight ratio of 2:1; 24 parts of paraffin microcapsules, prepared in this embodiment; 6 parts of redispersible rubber powder, using VINNAPAS®5044N type raw material; 0.9 parts of water reducer, using GK-3000 type polycarboxylate water reducer; and 78 parts of water.

[0053] Blending: Add ordinary Portland cement, aluminate cement, gypsum, mineral powder, paraffin microcapsules and redispersible rubber powder into a blender and stir at 30 rpm for 10 minutes. Disperse the water reducer into water and then add it to the mixture to mix well to obtain PCM-based energy storage building materials.

[0054] In a comparative example, a polyurea-coated paraffin-type phase change material was prepared with reference to the prior art and applied to energy storage building materials, as follows:

[0055] Isophorone diisocyanate, paraffin and emulsifier OP-10 were preheated to 40°C for miscibility, surfactant SDBS was dispersed in deionized water, heated to 60°C, added to the mixture, and shear emulsified at 1200 rpm for 5 minutes. After that, the stirring rate was reduced to 150 rpm, and tetraethylene pentamine was slowly added to react for 1 hour. The feed ratio of paraffin, isophorone diisocyanate, tetraethylene pentamine, emulsifier OP-10, surfactant SDBS and deionized water was 50 g: 2.5 g: 1.9 g: 0.8 g: 0.3 g: 150 mL. After the reaction was completed, the mixture was cooled and filtered to remove the aqueous phase. The substrate was washed with water and then vacuum dried to obtain a polyurea-coated paraffin-type phase change material.

[0056] Referring to Example 4, the paraffin microcapsules were replaced by an equal amount of polyurea-coated paraffin-type phase change material, and the rest of the implementation process was exactly the same.

[0057] Samples were taken from the paraffin microcapsules prepared in the above examples and the polyurea-coated paraffin phase change material prepared in the comparative example, and the latent heat of melting was measured by differential scanning calorimetry. The test temperature was 0-80°C and the temperature change rate was 5°C / min.

[0058] Samples were taken from the energy storage building materials prepared in the above examples and comparative examples, and block specimens were prepared according to the GB / T 17671-2021 standard. The samples were cured for 28 days and the compressive strength was tested.

[0059] Take the block sample as above and weigh it as M0. Place the sample in petroleum ether with a distillation range of 60-80℃ and cycle the temperature from 0-60℃ at a temperature change rate of 10℃ / min. The cycle periods are 100, 300 and 500 cycles respectively. After the cycle, take out the sample and dry it with hot air at 60℃ for 5 hours. Weigh it again and record it as M1. The leakage rate is calculated as (M0-M1) / M0×100%;

[0060] The specific test results are shown in Table 1:

[0061]

[0062] As can be seen from the test results in Table 1, the paraffin microcapsules prepared in the example and the polyurea-coated paraffin-type phase change material in the comparative example have similar latent heat of fusion, both reaching 100 J / g, which meets the application of building energy storage materials. The compressive strength of the energy storage building material using paraffin microcapsules in the example is slightly higher than that of the comparative example, and the leakage rate in the cycle test is much lower than that of the comparative example, showing excellent stability.

[0063] Throughout the specification, references to terms such as "one embodiment," "example," or "specific example" indicate that the specific features, structures, materials, or characteristics described in conjunction with that embodiment or example are included in at least one embodiment or example of the present invention. In this specification, schematic representations of these terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0064] The above contents are merely examples and explanations of the present invention. Those skilled in the art may make various modifications or additions to the described specific embodiments or replace them in similar ways. As long as they do not deviate from the invention or exceed the scope defined by the claims, they should all fall within the scope of protection of the present invention.

Claims

1. A PCM-based energy storage building material, characterized in that: The material comprises, by weight: 55-70 parts of ordinary Portland cement, 10-20 parts of aluminate cement, 10-15 parts of gypsum, 140-170 parts of fine aggregate, 15-25 parts of mineral powder, 18-26 parts of paraffin microcapsules, 5-7 parts of redispersible rubber powder, 0.8-1 part of water reducer and 75-83 parts of water; The paraffin microcapsules are prepared by the following method: Step A1: Premix pentamethylene glycol, triethylamine, and anhydrous tetrahydrofuran, dry under nitrogen protection, and control the temperature in a water bath at 10-20°C. Slowly add methylvinyldichlorosilane and stir to react for 1.5-2 hours. Then add propylene diamine, raise the temperature to 45-55°C, and stir to react for 30-40 minutes. After the reaction, remove tetrahydrofuran by rotary evaporation to obtain an intermediate; Step A2: Mix the intermediate, thioglycolic acid, photoinitiator and acetone, protect with nitrogen, and apply 150-200W / m 2 UV irradiation, stirring and reacting for 5-7 hours, after the reaction is completed, acetone is evaporated under reduced pressure to obtain a modifier; Step A3: preheating the paraffin wax and the modifier to dissolve them, adding deionized water to disperse them by shearing, controlling the temperature in a water bath at 50-60°C, stirring and slowly adding isophorone diisocyanate to react for 1-1.5 hours, then adding calcium oxide and continuing stirring for 2-3 hours. After the reaction is completed, cooling and filtering to remove the aqueous phase, washing the substrate with water and vacuum drying to obtain paraffin microcapsules; The feed ratio of methylvinyldichlorosilane, pentamethylene glycol, propylenediamine, triethylamine and anhydrous tetrahydrofuran is 0.1 mol: 80-90 mmol: 15-30 mmol: 6-10 mL: 45-55 mL; The feed ratio of the intermediate, thioglycolic acid, photoinitiator and acetone is 10 g: 35-50 mmol: 10-15 mg: 40-50 mL; The feeding ratio of paraffin wax, modifier, isophorone diisocyanate, calcium oxide and deionized water is 50g:4.5-6g:2.2-2.8g:12-16g:130-160mL.

2. The PCM-based energy storage building material according to claim 1, characterized in that: The fine aggregate is manufactured sand with a fineness modulus of 1.7-2.

5.

3. The PCM-based energy storage building material according to claim 1, characterized in that: Mineral powder is a mixture of limestone powder and fly ash.

4. The PCM-based energy storage building material according to claim 1, characterized in that: The water reducer is a polycarboxylic acid water reducer.

5. A method for preparing a PCM-based energy storage building material according to any one of claims 1 to 4, characterized in that: Specifically, ordinary Portland cement, aluminate cement, gypsum, mineral powder, paraffin microcapsules and redispersible rubber powder are premixed, fine aggregate is added and mixed evenly, and then a water reducer is dispersed in water and added to the mixture and mixed evenly to obtain a PCM-based energy storage building material.

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