A phase change energy storage aggregate, its preparation method and application

Abstract

This invention discloses a phase change energy storage aggregate, its preparation method, and its application, relating to the field of building materials technology. The phase change energy storage aggregate includes a phase change material, a carrier, and an encapsulation material. The phase change material is obtained by sequentially adding n-octanoic acid, n-tetradecane, and nano-graphite powder to n-decanoic acid. The carrier has a porous structure and is spherical or near-spherical, with the phase change material at least partially disposed within the pores or on the surface of the carrier. The encapsulation material is used to encapsulate the phase change material and the carrier. The phase change energy storage aggregate of this invention has a phase change temperature of 0–1°C, which can be used to delay and reduce snow accumulation and icing on concrete bridge decks during cooling, achieving anti-icing properties for concrete bridge decks. This invention reduces the flow of the phase change material by adsorbing it on the carrier, alleviating leakage, and uses a spherical or near-spherical carrier to improve the tightness of the encapsulation. Finally, the adhesive effect of the encapsulation material further improves the encapsulation effect and reduces leakage of the phase change material.

Description

Technical Field

[0001] This invention relates to the field of building materials technology, and in particular to a phase change energy storage aggregate, its preparation method, and its application. Background Technology

[0002] In my country's winters, the dramatic temperature differences and frequent rain and snow make concrete bridge surfaces highly susceptible to frost and ice formation. This significantly reduces the bridge's friction coefficient and increases the incidence of traffic accidents. Currently, the main methods for removing snow and ice from concrete bridges are sweeping, chemical de-icing, and heating de-icing. Sweeping requires manpower, closes roads, causes traffic disruptions, and is time-consuming. Chemical de-icing uses inorganic salts and other de-icing agents, which can corrode the concrete pavement. Heating de-icing involves installing geothermal pipes, heating wires, or infrared tubes inside or on the sides of the concrete bridge surface. When the bridge surface cools and freezes, these pipes are heated to melt the ice and snow. However, this method is relatively expensive in terms of pipe installation and electricity consumption.

[0003] Phase change materials (PCMs), also known as phase change energy storage materials, are materials that change their phase state (e.g., from solid to liquid or from liquid to solid) within a certain temperature range, i.e., the phase change temperature range, absorbing, storing, or releasing a large amount of heat in the form of latent heat while maintaining their own temperature. In recent years, some research has applied PCMs to concrete bridge decks, aiming to delay and reduce snow accumulation and icing on the concrete deck during cooling by incorporating PCMs into it. However, directly incorporating PCMs would cause direct contact between the PCMs and the concrete matrix, leading to leakage problems. Summary of the Invention

[0004] The main objective of this invention is to provide a phase change energy storage aggregate, its preparation method, and its application, aiming to solve the problem of easy leakage of phase change materials during the use of phase change energy storage aggregate.

[0005] To achieve the above objectives, the present invention provides a phase change energy storage aggregate for anti-icing of concrete bridge decks, comprising:

[0006] Phase change materials;

[0007] The carrier includes a porous structure, wherein the phase change material is at least partially disposed in the pores or on the surface of the carrier;

[0008] An encapsulation material, wherein the encapsulation material is used to encapsulate the phase change material and the carrier;

[0009] The phase change material is obtained by sequentially adding n-octanoic acid, n-tetradecane, and nano-graphite powder to n-decanoic acid;

[0010] The carrier is spherical or near-spherical.

[0011] Optionally, the mass ratio of the n-decanoic acid, n-octanoic acid, n-tetradecane and nano-graphite powder is (10-12):(21-23):(13-15):(2-4).

[0012] Optionally, the compressive strength of the carrier is 7–9 MPa; and / or,

[0013] The carrier includes fly ash ceramsite.

[0014] Optionally, the encapsulation material includes at least one of polyvinyl alcohol solution and cement slurry, wherein,

[0015] The polyvinyl alcohol solution is obtained by mixing polyvinyl alcohol powder and water in a mass ratio of (0.1–0.12):(0.88–0.9); and / or,

[0016] The cement slurry is obtained by mixing cement and water in a mass ratio of (0.5 to 0.55):1.

[0017] This invention provides a method for preparing phase change energy storage aggregate, comprising the following steps:

[0018] The carrier and phase change material are mixed so that the phase change material is adsorbed into at least part of the pores or surface of the carrier to obtain unencapsulated phase change aggregate.

[0019] Unencapsulated phase change aggregate is mixed with encapsulation material, so that the unencapsulated phase change aggregate is encapsulated by the encapsulation material to obtain phase change energy storage aggregate.

[0020] Optionally, in the step of mixing the carrier and the phase change material to obtain unencapsulated phase change aggregate, the mixing of the carrier and the phase change material includes mixing the carrier and the phase change material under water bath heating conditions, water bath heating and stirring conditions, or vacuum impregnation conditions.

[0021] Optionally, the mass ratio of the phase change material to the carrier is (2-3):5.

[0022] Optionally, in the step of mixing unencapsulated phase change aggregate and encapsulation material to encapsulate the unencapsulated phase change aggregate and obtain phase change energy storage aggregate, the mass ratio of the unencapsulated phase change aggregate to the encapsulation material is (13:50) to (9:25).

[0023] Optionally, the mixing of the unencapsulated phase change aggregate and the encapsulating material includes one of the following methods:

[0024] (a) Mixing unencapsulated phase change aggregate with a polyvinyl alcohol solution;

[0025] (b) Mix the unencapsulated phase change aggregate with cement slurry;

[0026] (c) The unencapsulated phase change aggregate is mixed sequentially with polyvinyl alcohol solution and cement slurry.

[0027] The present invention provides a concrete comprising aggregate, wherein the aggregate comprises the phase change energy storage aggregate described above, or phase change energy storage aggregate prepared by the method of preparing the phase change energy storage aggregate described above.

[0028] The beneficial effects of this invention are as follows:

[0029] (1) The phase change energy storage aggregate of the present invention has a phase change temperature of 0 to 1°C. When the phase change energy storage aggregate is used in concrete, when the air temperature drops to near 0°C, the phase change material in the phase change energy storage aggregate solidifies from a liquid state to a solid state, releasing a large amount of heat at the same time, which greatly slows down the temperature drop of the concrete bridge deck and achieves an anti-icing effect. Since the phase change material only undergoes a rapid phase change near 0°C to raise the ambient temperature to the phase change temperature, it can also reduce the problem of premature heat loss.

[0030] (2) By adsorbing phase change material (PCM) onto a carrier with a porous structure, the fluidity of PCM is reduced, mitigating PCM leakage. Furthermore, spherical or near-spherical carriers are selected. When a regular carrier and encapsulation material are mixed, the carrier can be fully encapsulated by the encapsulation material, improving encapsulation tightness and reducing PCM leakage. Finally, the encapsulation material is used to encapsulate both the PCM and the carrier, utilizing its adhesive properties to further improve the encapsulation effect and reduce PCM leakage. The PCM energy storage aggregate provided by this invention exhibits excellent encapsulation performance, with minimal mass change after phase change cycling, thus improving the PCM leakage problem. Attached Figure Description

[0031] Figure 1 The graph shows the adsorption rate test results of phase change energy storage aggregates in Examples 2, 5, and 6 of this invention.

[0032] Figure 2 These are the mass loss test results of phase change energy storage aggregates in Examples 2-4 and Comparative Example 2 of the present invention;

[0033] Figure 3 These are the compressive strength test results of phase change energy storage aggregates in Examples 2-4 and Comparative Examples 1-2 of the present invention.

[0034] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0035] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Where the manufacturers of reagents or instruments are not specified, they are all conventional products that can be purchased commercially. Furthermore, the meaning of "and / or" throughout the text includes three parallel solutions; for example, "A and / or B" includes solution A, or solution B, or a solution where both A and B are satisfied simultaneously. In addition, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0036] Concrete bridge decks are an important component of my country's road and bridge structures, accounting for a significant proportion of existing bridge decks. Their normal use and operation affect our economic development and the speed of personnel and material transportation. However, under the influence of severe temperature differences and rain and snow in my country's winters, concrete bridge decks exposed to the actual environment are prone to frost and ice formation. This significantly reduces the friction coefficient of the bridge deck, increasing the incidence of traffic accidents. Once a traffic accident occurs, it not only reduces the bridge's transportation efficiency and affects the travel of people and the delivery of goods, but also poses a great threat to people's lives, causing incalculable losses.

[0037] Currently, the main methods for removing snow and ice from concrete bridges are sweeping, chemical de-icing, and heating de-icing. Sweeping requires manpower, closes roads, causes traffic congestion, and takes a long time. Chemical de-icing uses inorganic salts and other de-icing agents to melt snow, which can corrode the concrete pavement. Heating de-icing involves installing geothermal pipes, heating wires, or infrared tubes inside or on both sides of the concrete bridge deck. When the bridge deck cools and freezes, these pipes are heated to melt the ice and snow. However, this method has relatively high pipe installation and electricity costs.

[0038] Phase change materials (PCMs), also known as phase change energy storage materials, are materials that change their phase state (e.g., from solid to liquid or from liquid to solid) within a certain temperature range, i.e., the phase change temperature range, absorbing, storing, or releasing a large amount of heat in the form of latent heat while maintaining a constant temperature themselves. In recent years, research has focused on applying PCMs to cement concrete, aiming to achieve snow and ice melting effects by incorporating PCMs into the concrete. However, the application of PCMs in concrete also presents other problems, such as the ease of leakage of PCMs, a significant decline in quality after multiple phase change cycles, and a decrease in the compressive strength of concrete as the amount of PCM added increases.

[0039] In view of this, the present invention provides a phase change energy storage aggregate for anti-icing of concrete bridge decks, comprising:

[0040] Phase change materials;

[0041] The carrier includes a porous structure, wherein the phase change material is at least partially disposed in the pores or on the surface of the carrier;

[0042] An encapsulation material, wherein the encapsulation material is used to encapsulate the phase change material and the carrier;

[0043] The phase change material is obtained by sequentially adding n-octanoic acid, n-tetradecane, and nano-graphite powder to n-decanoic acid;

[0044] The carrier is spherical or near-spherical.

[0045] The phase change material in this invention's phase change energy storage aggregate is obtained by sequentially adding n-octanoic acid, n-tetradecane, and nano-graphite powder to n-decanoic acid. The phase change temperature is between 0 and 1°C. When this phase change energy storage aggregate is used in concrete, as the air temperature drops close to 0°C, the phase change material in the aggregate solidifies from a liquid state to a solid state, releasing a large amount of heat. This significantly slows down the temperature drop of the concrete bridge deck, achieving an anti-icing effect. Because the phase change material rapidly undergoes a phase change near 0°C, raising the ambient temperature to the phase change temperature, it also reduces the problem of premature heat loss.

[0046] This invention uses a carrier with a porous structure to adsorb phase change materials, which can reduce the fluidity of phase change materials and alleviate the leakage problem. Furthermore, by using an encapsulation material, the adhesive effect of the encapsulation material is utilized to further reduce the leakage of phase change materials. Moreover, the carrier selected in this invention is spherical or near-spherical. When the carrier and the encapsulation material are mixed, the carrier is fully encapsulated by the encapsulation material, which can improve the encapsulation effect of the phase change material.

[0047] In any embodiment of the present invention, the compressive strength of the carrier is 7–9 MPa. Generally, as the amount of phase change energy storage aggregate increases, the compressive strength of concrete decreases significantly, and the strength of the carrier affects the compressive strength of the concrete. When the compressive strength is between 7 and 9 MPa, the carrier exhibits good adsorption and compressive strength properties.

[0048] In any embodiment of the present invention, the carrier comprises fly ash ceramsite. Fly ash ceramsite has relatively few interconnected pores and a dense, honeycomb-like internal structure, exhibiting advantages such as low density, high strength, and good frost resistance. In the technical solution of the present invention, spherical fly ash ceramsite with a particle size of 5–20 mm is selected as the carrier for adsorbing phase change material, resulting in good adsorption effect, and the prepared phase change energy storage aggregate exhibits good compressive strength after being applied to concrete.

[0049] In any embodiment of the present invention, the encapsulation material includes at least one of polyvinyl alcohol solution and cement slurry.

[0050] The encapsulation material includes at least one of polyvinyl alcohol solution and cement slurry. That is, the encapsulation material includes any one of polyvinyl alcohol solution and cement slurry, or may contain both polyvinyl alcohol solution and cement slurry, all of which fall within the scope of protection of this invention. Encapsulation can prevent liquid phase change material from leaking from the pores of the aggregate, thus affecting the use of phase change energy storage aggregate.

[0051] In any embodiment of the present invention, the polyvinyl alcohol solution is obtained by mixing polyvinyl alcohol powder and water at a mass ratio of (0.1-0.12):(0.88-0.9). Using a polyvinyl alcohol solution within the above range provides good adhesion, effectively encapsulating the phase change aggregate and sealing pores, forming a barrier to prevent leakage of the phase change material.

[0052] In any embodiment of the present invention, the cement slurry is obtained by mixing cement and water in a mass ratio of (0.5 to 0.55):1. The cement slurry obtained by mixing cement and water in a mass ratio of (0.5 to 0.55):1 exhibits good bonding properties, forming a barrier to prevent leakage of the phase change material. Simultaneously, the encapsulation layer using the cement slurry as the encapsulation material has good material compatibility with the external substrate, ensuring the strength of the phase change concrete.

[0053] This invention provides a method for preparing phase change energy storage aggregate, comprising the following steps:

[0054] The carrier and phase change material are mixed so that the phase change material is adsorbed into at least part of the pores or surface of the carrier to obtain unencapsulated phase change aggregate.

[0055] Unencapsulated phase change aggregate is mixed with encapsulation material, so that the unencapsulated phase change aggregate is encapsulated by the encapsulation material to obtain phase change energy storage aggregate.

[0056] By mixing the carrier and the phase change material, the phase change material is allowed to penetrate into the pores of the carrier, reducing its fluidity and thus minimizing leakage. Furthermore, encapsulation with a sealing material prevents the phase change material from flowing out of the carrier's pores, further reducing leakage and allowing the phase change energy storage aggregate to better fulfill its phase change energy storage function.

[0057] In any embodiment of the present invention, before the step of mixing the carrier and the phase change material to allow the phase change material to be adsorbed into at least a portion of the pores or surface of the carrier to obtain unencapsulated phase change aggregate, the carrier is dried at a constant temperature of 95–105°C for 24 hours.

[0058] In any embodiment of the present invention, the step of mixing the carrier and the phase change material to obtain unencapsulated phase change aggregate by adsorbing the phase change material into at least a portion of the pores or surface of the carrier is further described as mixing the carrier and the phase change material under water bath heating conditions, water bath heating and stirring conditions, or vacuum impregnation conditions.

[0059] The adsorption method determines the final adsorption amount of the phase change material. The more phase change material the aggregate absorbs, the greater the latent heat of phase change and the better the temperature control effect. In some embodiments of the present invention, water bath heating is performed at 40°C, water bath heating and stirring is performed at 40°C and 30 r / min, and vacuum impregnation is performed in a vacuum impregnation machine.

[0060] In any embodiment of the present invention, the mass ratio of the phase change material to the carrier is (2-3):5. Setting the mass ratio of the phase change material to the carrier at (2-3):5 allows the carrier to fully adsorb the phase change material while avoiding material waste.

[0061] In any embodiment of the present invention, in the step of mixing unencapsulated phase change aggregate and encapsulation material to encapsulate the unencapsulated phase change aggregate and obtain phase change energy storage aggregate, the mass ratio of the unencapsulated phase change aggregate to the encapsulation material is (13:50) to (9:25). When the mass ratio of the unencapsulated phase change aggregate to the encapsulation material is (13:50) to (9:25), the encapsulation material can fully encapsulate the unencapsulated phase change aggregate, resulting in a better encapsulation effect while avoiding material waste.

[0062] In any embodiment of the present invention, the mixing of the unencapsulated phase change aggregate and the encapsulating material includes one of the following methods:

[0063] (a) Mixing unencapsulated phase change aggregate with a polyvinyl alcohol solution;

[0064] (b) Mix the unencapsulated phase change aggregate with cement slurry;

[0065] (c) The unencapsulated phase change aggregate is mixed sequentially with polyvinyl alcohol solution and cement slurry.

[0066] It should be noted that when mixing in methods (b) and (c), cement slurry is used. After the unencapsulated phase change aggregate is wrapped with the encapsulating material, water curing is required. During the water curing period, the aggregate needs to be continuously moved to prevent sticking. The curing method is to place it in a curing box, where the curing temperature is 20-25℃, the curing humidity is 90-95%, and the curing period is 7 days.

[0067] This invention provides a concrete comprising aggregate, wherein the aggregate includes the aforementioned phase change energy storage aggregate, or phase change energy storage aggregate prepared by the aforementioned phase change energy storage aggregate preparation method. The concrete incorporates all the technical solutions of phase change energy storage aggregate, and therefore possesses all the beneficial effects of phase change energy storage aggregate, which will not be elaborated upon here.

[0068] The technical solution of the present invention will be further described in detail below with reference to specific embodiments. It should be understood that the following embodiments are only used to explain the present invention and are not intended to limit the present invention.

[0069] In the following embodiments, the phase change material is composed of n-decanoic acid, n-octanoic acid, n-tetradecane and nano-graphite powder, and the mass ratio of n-decanoic acid, n-octanoic acid, n-tetradecane and nano-graphite powder is 11:22:14:3.

[0070] The carrier is spherical fly ash ceramsite;

[0071] In the polyvinyl alcohol solution, the mass ratio of polyvinyl alcohol to water is 3:22;

[0072] In cement slurry, the mass ratio of cement to water is 11:20;

[0073] The mass ratio of phase change material to carrier is 2:5;

[0074] The mass ratio of unencapsulated phase change aggregate to encapsulating material is 30:16;

[0075] The fly ash ceramsite used is spherical fly ash ceramsite produced by Henan Deheng Renewable Resources Co., Ltd.

[0076] The polyvinyl alcohol powder used is AR grade 1788 polyvinyl alcohol powder produced by Wuxi Yatai United Chemical Co., Ltd.

[0077] The cement used is PO 42.5 type ordinary Portland cement produced by Liquan Conch Cement Co., Ltd.

[0078] Example 1

[0079] A phase change energy storage aggregate includes a phase change material, a carrier, and an encapsulation material. The phase change material includes n-decanoic acid, n-octanoic acid, n-tetradecane, and nano-graphite powder, wherein the mass ratio of n-decanoic acid, n-octanoic acid, n-tetradecane, and nano-graphite powder is 11:22:14:3. The carrier is spherical fly ash ceramsite, and the encapsulation material is polyvinyl alcohol (PVA) solution and cement slurry.

[0080] Example 2

[0081] A method for preparing phase change energy storage aggregate, the specific steps of which are as follows:

[0082] (1) The fly ash ceramsite was dried at a constant temperature of 95-105℃ for 24 hours; in this embodiment, the compressive strength of the fly ash ceramsite was 7.2MPa, and the fly ash ceramsite was spherical.

[0083] (2) 88g of octanoic acid, 56.5g of n-tetradecane and 12g of nano-graphite powder were added sequentially to 43.5g of n-decanoic acid to obtain a phase change material;

[0084] (3) Mix 500g of fly ash ceramsite and 200g of phase change material in a water bath at 40℃ and 30r / min, so that the fly ash ceramsite can adsorb the phase change material and obtain 600g of unencapsulated phase change aggregate. After completion, place it at room temperature and pressure for 24h.

[0085] (4) Use 160g of PVA solution (PVA to water mass ratio of 3:22) to encapsulate 600g of unencapsulated phase change aggregate and dry it at room temperature for 12h;

[0086] (5) Use 160g of cement slurry (the mass ratio of cement to water is 11:20) to encapsulate the material obtained in step (4);

[0087] (6) Place the material obtained in step (5) in a curing box at 25°C and 95% humidity for 7 days to obtain phase change energy storage aggregate.

[0088] Example 3

[0089] This embodiment uses a preparation method similar to that of Example 2, except that steps (5) and (6) are not performed.

[0090] Example 4

[0091] This embodiment uses a preparation method similar to that of Example 2, except that step (4) is not performed.

[0092] Example 5

[0093] This embodiment uses a preparation method similar to that of Example 2, except that the mixing method of fly ash ceramsite and phase change material in step (3) is a water bath heating at 40°C.

[0094] Example 6

[0095] This embodiment uses a preparation method similar to that of Example 2, except that the mixing method of fly ash ceramsite and phase change material in step (3) is vacuum impregnation.

[0096] Comparative Example 1

[0097] This comparative example uses a preparation method similar to that of Example 2, except that step (1) is not performed and fly ash ceramsite is not added when step (3) is performed.

[0098] Comparative Example 2

[0099] This comparative example uses a preparation method similar to that of Example 2, except that steps (4) to (6) are not performed.

[0100] Table 1. Parameters of Examples 2-6 and Comparative Examples 1-2

[0101]

[0102] In Table 1, “-” in Comparative Example 1 means that no fly ash ceramsite was added, that is, no mixing of fly ash ceramsite and phase change material was carried out; “-” in Comparative Example 2 means that no encapsulation material was used, that is, no polyvinyl alcohol solution or cement slurry was used.

[0103] Performance testing

[0104] The adsorption effect, encapsulation effect, and compressive strength of the phase change energy storage aggregates in Examples 2-6 and Comparative Examples 1-2 were tested, and the test results are as follows: Figures 1-3 As shown in Table 2.

[0105] The test methods for adsorption effect, encapsulation effect, and compressive strength are as follows:

[0106] Adsorption effect evaluation: The adsorption rate of the phase change material adsorbed on the carrier after 24 hours is used as the measure. The higher the adsorption rate, the better the adsorption effect, the greater the latent heat of phase change of the phase change material, and the better the temperature control effect. Adsorption rate = (mass of carrier after adsorption - mass of carrier before adsorption) / (mass of carrier before adsorption) × 100%. The vacuum adsorption test was conducted using a DZF-6210AB vacuum drying oven manufactured by Shanghai Lichen Bangxi Instrument Technology Co., Ltd.

[0107] Encapsulation effect evaluation: The mass loss rate of the phase change energy storage aggregate after 200 phase change cycles is used as the evaluation metric. The smaller the mass loss rate of the phase change energy storage aggregate, the better the encapsulation effect of the phase change material. Mass loss rate = (mass before 200 phase change cycles - mass after 200 phase change cycles) / (mass before 200 phase change cycles) × 100%. The phase change cycle experiment was conducted using a TDR-28 rapid freeze-thaw tester manufactured by Tianjin Gangyuan Instrument Experiment Factory. The aggregate was frozen at -18℃ for 4 hours and then thawed at 5℃ for 4 hours, which constituted one phase change cycle. After every 50 cycles, the phase change energy storage aggregate was removed, the surface of any leaked phase change material was wiped dry with filter paper, and the mass was weighed to observe the mass change of the phase change energy storage aggregate after multiple phase change cycles.

[0108] Compressive strength assessment: Cement mortar was prepared according to GB / T17671-1999, using a cement:sand:water mass ratio of 2:6:1. Phase change energy storage aggregate was added at 10% of the cement mass. After curing for 28 days, the compressive strength was tested to observe the effect of different encapsulation methods on the strength. The compressive strength test was conducted using an E64.206 electro-hydraulic servo universal testing machine manufactured by Mester Industrial Systems Co., Ltd.

[0109] Table 2 Performance test results of phase change energy storage aggregates in Examples 2-6 and Comparative Examples 1-2

[0110] Example 2 19.8 1.0 36 Example 3 19.8 1.9 38 Example 4 19.8 3.2 33.5 Example 5 6.9 - - Example 6 14.7 - - Comparative Example 1 - - 42 Comparative Example 2 19.8 12.2 29.5 Conventional phase change energy storage aggregate 10.5 21.3 26.3

[0111] In Table 2, "-" indicates that the test was not performed.

[0112] Figure 1 The graph shows the adsorption rate test results of phase change energy storage aggregates in Examples 2, 5, and 6 of this invention. Example 2 was conducted under water bath heating and stirring conditions, Example 5 under water bath heating conditions, and Example 6 under vacuum impregnation conditions. (See Table 2 for details.) Figure 1 It can be seen that the final adsorption rate is highest under water bath heating and stirring conditions. This is because the water bath heating and stirring method can rely on the eddy currents generated by the rotor to fully mix the phase change material with the carrier, enhancing the self-adsorption effect of the carrier. Figure 1 It can also be seen that the carriers in Examples 2, 5, and 6 reached their final adsorption rates in 24 hours.

[0113] Figure 2 The figures show the mass loss test results of phase change energy storage aggregates in Examples 2-4 and Comparative Example 2 of this invention. Example 2 involved encapsulation using PVA solution and cement slurry sequentially; Example 3 involved encapsulation using PVA solution; Example 4 involved encapsulation using cement slurry; and Comparative Example 2 involved no encapsulation. (Table 2 and...) Figure 2It can be seen that after multiple phase change cycles, the mass of the phase change energy storage aggregates in Examples 2-4 and Comparative Example 2 continuously decreases with the increase of the number of cycles. Furthermore, the mass loss rate of the phase change energy storage aggregates in Examples 2-4 is less than 4%, significantly lower than that of the phase change energy storage aggregate in Comparative Example 2, indicating that encapsulation of the phase change energy storage aggregate can reduce its mass loss. In addition, the mass loss rate of Example 2 is lower than that of Examples 3 and 4, indicating that encapsulation using PVA solution and cement slurry sequentially is more effective than encapsulation using only PVA or only cement slurry. Moreover, as shown in Table 2, compared with conventional phase change energy storage aggregates, the encapsulation effect of the phase change energy storage aggregate provided by this invention is superior, and the mass loss of the phase change energy storage aggregate is even smaller after multiple phase change cycles.

[0114] Figure 3 Table 2 shows the compressive strength test results of phase change energy storage aggregates in Examples 2-4 and Comparative Examples 1-2 of this invention. Example 2 involved encapsulation using PVA solution and cement slurry sequentially; Example 3 involved encapsulation using PVA solution; Example 4 involved encapsulation using cement slurry; Comparative Example 1 did not use fly ash ceramsite; and Comparative Example 2 did not involve encapsulation. (From Table 2 and...) Figure 3 It can be seen that when the phase change material is adsorbed by the carrier fly ash ceramsite, the compressive strength of the material will decrease, as shown in Table 2 and... Figure 3 It can also be seen that, compared with Comparative Example 2, the phase change energy storage aggregates of Examples 1-2 have greater compressive strength, indicating that encapsulation can improve the compressive strength of phase change energy storage aggregates. Furthermore, as shown in Table 2, compared with conventional phase change energy storage aggregates, the compressive strength of the phase change energy storage aggregates provided by this invention is superior.

[0115] The above are merely preferred embodiments of the present invention and do not limit the patent scope of the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the patent protection scope of the present invention.

Claims

1. A method for preparing phase change energy storage aggregate, characterized in that, Includes the following steps: A carrier and a phase change material are mixed, so that the phase change material is adsorbed into at least a portion of the pores or surface of the carrier to obtain unencapsulated phase change aggregate; the carrier includes spherical fly ash ceramsite. Unencapsulated phase change aggregate is mixed with encapsulation material, so that the unencapsulated phase change aggregate is encapsulated by the encapsulation material to obtain phase change energy storage aggregate. The carrier and phase change material are mixed under water bath heating and stirring conditions; The phase change material is obtained by sequentially adding n-octanoic acid, n-tetradecane, and nano-graphite powder to n-decanoic acid; The mass ratio of n-decanoic acid, n-octanoic acid, n-tetradecane and nano-graphite powder is (10~12):(21~23):(13~15):(2~4). The encapsulation material includes at least one of a polyvinyl alcohol solution and a cement slurry, wherein the polyvinyl alcohol solution is obtained by mixing polyvinyl alcohol powder and water in a mass ratio of (0.1~0.12):(0.88~0.9); The cement slurry is obtained by mixing cement and water in a mass ratio of (0.5~0.55):

1.

2. The method for preparing phase change energy storage aggregate as described in claim 1, characterized in that, The carrier includes a porous structure; The carrier is spherical or near-spherical; The compressive strength of the carrier is 7~9 MPa.

3. The method for preparing phase change energy storage aggregate as described in claim 1, characterized in that, The mass ratio of the phase change material to the carrier is (2~3):

5.

4. The method for preparing phase change energy storage aggregate as described in claim 1, characterized in that, In the step of mixing unencapsulated phase change aggregate and encapsulation material to encapsulate the unencapsulated phase change aggregate and obtain phase change energy storage aggregate, the mass ratio of the unencapsulated phase change aggregate to the encapsulation material is (13:50) to (9:25).

5. The method for preparing phase change energy storage aggregate as described in claim 1, characterized in that, The mixing of unencapsulated phase change aggregate and encapsulating material includes one of the following methods: (a) Mixing unencapsulated phase change aggregate with a polyvinyl alcohol solution; (b) Mix the unencapsulated phase change aggregate with cement slurry; (c) The unencapsulated phase change aggregate is mixed sequentially with polyvinyl alcohol solution and cement slurry.

6. A type of concrete, characterized in that, The concrete includes aggregates, wherein the aggregates include phase change energy storage aggregates prepared by the method for preparing phase change energy storage aggregates as described in any one of claims 1-5.

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