Phase change temperature adjusting wall and preparation method

Abstract

The invention provides a phase-change temperature-regulating wall and a preparation method, relates to the field of phase-change materials, and aims to solve the problem of complex construction caused by the fact that a thermal insulation layer made of a current phase-change material still needs to be combined with an existing building structure. The problem that the phase-change lightweight aggregate is prone to leakage is solved, the prepared small-particle-size phase-change lightweight aggregate can be used for preparing phase-change concrete, can be directly used as a structural layer, has good heat storage and heat preservation performance, forms wallboards in combination with an anti-cracking layer, a steel mesh connecting layer, a foam heat preservation layer and the like, and then is subjected to wallboard combination construction to obtain a phase-change temperature adjustment wall. And the construction efficiency requirement of prefabricated modular construction is met.

Description

Technical Field

[0001] The present invention relates to the field of phase change materials, and in particular to a phase change temperature regulating wall and a preparation method thereof. Background Art

[0002] At present, there are two main ways to apply phase change materials in building insulation. One is to use porous metal materials and lightweight porous materials as carriers to carry and adsorb composite phase change materials, which are then directly used as building materials to prepare phase change insulation wall materials. However, this type of use often has a great impact on the performance of building materials. The direct introduction of porous lightweight materials reduces the mechanical properties of building materials, while the large-scale introduction of porous metal materials will cause serious thermal bridge effects. Therefore, this type of use can mostly only use phase change insulation wall materials as an additional insulation layer, which increases the overall construction complexity of the exterior wall. At the same time, this type of application cannot effectively prevent the leakage of phase change materials. The second is to use phase change microcapsules in building materials. Compared with the first method, it has less impact on strength and can be purchased and applied directly, eliminating the steps of preparing composite phase change materials and simplifying the construction process, but the cost is high and it is difficult to promote on a large scale.

[0003] The existing technology provides some methods for preparing phase-change lightweight aggregates, and the prepared phase-change lightweight aggregates are applied to thermal insulation building materials. The phase-change lightweight aggregates have phase-change heat storage function, high strength and leakage prevention. The phase-change thermal insulation building materials for thermal bridges provided are suitable for on-site casting in thermal bridge environments, which can effectively eliminate the thermal bridge phenomenon and improve the thermal comfort of the building; but they are still used as insulation layers. The phase-change thermal insulation building materials for thermal bridges are covered on the outside of the building structure and need to be cast on-site. The construction is relatively complicated, which extends the project construction period and is difficult to meet the current needs of prefabricated modular rapid construction. Summary of the Invention

[0004] The present invention aims to address the defects of the prior art and provide a phase change temperature control wall and preparation method. The invention uses expanded perlite to absorb paraffin, and then uses a cementitious material to seal the pores of the expanded perlite to prepare a phase change lightweight aggregate with a particle size of 2.35mm-5mm. The density of the concrete is improved by grading optimization, the leakage prevention performance is enhanced by the advantage of specific surface area, and the fluidity is adapted to the prefabrication process for optimization from multiple angles. The problem of the phase change lightweight aggregate being prone to leakage is solved, and the functional leap from an auxiliary insulation material to a main structural material is achieved. The prepared small-particle phase change lightweight aggregate can be used to prepare phase change concrete. The phase change concrete also uses a sulphoaluminate cementitious material. The crystal-colloid composite system provides the dual functions of aggregate strength, efficient encapsulation, and prevention of phase change material leakage, so that the phase change concrete can be directly used as a structural layer such as a phase change insulation wall. It has good heat storage and thermal insulation properties. It is combined with an anti-cracking layer, a steel mesh connecting layer, a foam insulation layer, etc. to form a wall panel, and then the wall panel is combined to obtain a phase change temperature control wall, meeting the construction efficiency requirements of prefabricated modular construction.

[0005] The first object of the present invention is to provide a phase change temperature control wall, which adopts the following scheme: Including phase change concrete, the phase change concrete is composed of the following components in parts by mass: 30-50 parts of phase change lightweight aggregate, 20-30 parts of gravel, 15-20 parts of sulphoaluminate cementitious material, 10-20 parts of water; The phase change lightweight aggregate is prepared by combining expanded perlite with phase change material paraffin, and the particle size of the phase change lightweight aggregate is 2.35mm-5mm; The sulphoaluminate cementitious material comprises: 40-50 parts of sulphoaluminate cement, 10-20 parts of ordinary Portland cement, 5-10 parts of desulfurized building gypsum, 20-35 parts of mineral powder, and 0.1-0.5 parts of water reducing agent.

[0006] Furthermore, the preparation method of the phase change lightweight aggregate includes: Expanded pearlite absorbs phase change material paraffin to obtain a composite phase change material; The composite phase change material and the cementitious material are mixed and granulated to obtain a phase change lightweight aggregate with a particle size of 2.35 mm to 5 mm.

[0007] Furthermore, the expanded perlite adsorbing phase change material paraffin comprises: 25-33.3 parts by mass of expanded perlite and 66.7-75 parts by mass of paraffin are mixed and impregnated.

[0008] Furthermore, vacuum impregnation is performed under negative pressure at 40° C.-60° C. for 3 h-8 h.

[0009] Furthermore, the particle size of the expanded perlite is 1.18 mm to 2.35 mm, and the gelling material is sulphoaluminate gelling material.

[0010] Furthermore, the granulation comprises: Screening the composite phase change material with a particle size distribution of 1.18 mm to 2.35 mm and adding it to the granulator; Phase change lightweight aggregate is obtained through a granulator.

[0011] Furthermore, when the composite phase change material is added into the granulator, 20% to 30% of the mass of the composite phase change material is added for pre-wetting.

[0012] Furthermore, the phase change concrete is combined with an anti-cracking layer, a steel mesh connection layer, and a foam insulation layer to form a wall panel.

[0013] The second object of the present invention is to provide a method for preparing a phase change temperature control wall, which comprises the following steps: soaking the phase change lightweight aggregate, removing the water after saturation and draining it to obtain pre-wetted phase change lightweight aggregate; Sulphoaluminate cement, ordinary Portland cement, desulfurized building gypsum, mineral powder and water reducing agent are mixed in proportion to obtain a mixed powder; Add water to the mixed powder and stir to form a slurry. Add stones and pre-wetted phase change lightweight aggregate into the slurry, continue stirring until evenly mixed, and then pour it into the mold; After initial setting, the anti-cracking layer, steel mesh connection layer and foam insulation layer are filled to form wall panels, and the phase change temperature control wall is obtained by combining the wall panels.

[0014] Furthermore, the prepared phase change lightweight aggregate is soaked in water for 2 hours, the mixed powder is added with water and stirred for 2 minutes to 3 minutes, and the slurry is added with gravel and pre-wetted phase change lightweight aggregate and stirred for another 2 minutes to 3 minutes.

[0015] Compared with the prior art, the present invention has the following advantages and positive effects: In view of the problem that the insulation layer made of current phase change materials still needs to be combined with the existing building structure, which leads to complicated construction, expanded perlite is used to absorb paraffin, and then the pores of the expanded perlite are sealed with cementitious materials, which solves the problem that phase change lightweight aggregate is prone to leakage. The small-particle phase change lightweight aggregate produced can be used to prepare phase change concrete, which can be used directly as a structural layer and has good heat storage and thermal insulation properties. It is combined with an anti-cracking layer, a steel mesh connecting layer, a foam insulation layer, etc. to form a wall panel, and then the wall panel combination is used to obtain a phase change temperature-regulating wall, which meets the construction efficiency requirements of prefabricated modular construction.

[0016] Phase change concrete was prepared using 2.35mm-5mm phase change lightweight aggregate and then formed into phase change temperature control wall. The obtained test block had a 28d compressive strength of up to 48MPa, a flexural strength of 8MPa, and an overall density of 1432kg / , and can be used directly as an exterior wall structural layer. Compared to the prior art phase-change insulation building materials for thermal bridges, which have a 28-day compressive strength exceeding 5MPa, the phase-change lightweight aggregate in this invention performs even better in optimizing mechanical properties, better meeting the load-bearing requirements of the exterior wall as a structural layer.

[0017] The particle size of phase-change lightweight aggregate is limited to 2.35mm-5mm. It is a systematic design based on the function of the structural layer. It improves the density of concrete through grading optimization, enhances the anti-leakage performance through the advantage of specific surface area, and optimizes the prefabrication process from multiple angles through fluidity adaptation. This enables phase-change lightweight aggregate to meet the needs of structural main materials and ultimately achieve a functional leap from auxiliary insulation material to structural main material.

[0018] Sulphoaluminate cementitious material adopts a composite formula of 40-50 parts of sulphoaluminate cement and 10-20 parts of ordinary Portland cement. Through the synergistic effect of the two cements, it not only retains the characteristics of fast hardening and early strength of sulphoaluminate cement, but also optimizes the later strength stability through ordinary Portland cement, while reducing the leakage risk of phase change material.

[0019] Sulphoaluminate cement is a solid waste-based sulphoaluminate cement, formed in conjunction with Portland cement, by-product desulfurized building gypsum, and mineral powder to form a composite system. It encapsulates phase-change lightweight aggregate and serves as the aggregate shell. The large amount of needle-shaped ettringite produced by the hydration of sulphoaluminate cement forms a strong skeleton structure, providing excellent mechanical properties. The hydrated calcium silicate colloid formed by the hydration of ordinary Portland cement fills the pores of the skeleton, making the structure more compact. This crystal-colloid composite system provides aggregate strength and efficient encapsulation, preventing leakage of the phase-change material. The addition of by-product desulfurized building gypsum, mineral powder, and other materials not only consumes accumulated solid waste and improves environmental benefits, but also works synergistically to further enhance early strength and rapid setting properties, improving construction and production efficiency and shortening the production cycle. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The accompanying drawings, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0021] Figure 1 Schematic diagram of the process for preparing phase change lightweight aggregate in Example 1 of the present invention.

[0022] Figure 2 This is a SEM image of the aggregate shell formed by the sulphoaluminate cementitious material in Example 1 of the present invention. Figure 2 (a) is a SEM image of the aggregate shell formed by the sulphoaluminate cementitious material in Example 1 of the present invention, Figure 2 (b) is a SEM image of another area of ​​the aggregate shell formed by the sulphoaluminate cementitious material in Example 1 of the present invention.

[0023] Figure 3 Schematic diagram of the microstructure of expanded perlite and cementitious material in Example 1 of the present invention, Figure 3 (a) is a schematic diagram of the microstructure of the shell formed by the expanded perlite of the aggregate core and the cementitious material in Example 1 of the present invention, Figure 3 (b) is a schematic diagram of the microstructure of another region of the shell formed by the expanded perlite and cementitious material in the aggregate core in Example 1 of the present invention, Figure 3 (c) is a line scan result of the shell formed by the expanded perlite in the aggregate core and the cementitious material in Example 1 of the present invention. DETAILED DESCRIPTION

[0024] The components used in the following examples and comparative examples are all conventional commercial products unless otherwise specified. The water reducer is a polycarboxylate water reducer, the particle size of the expanded perlite is 1.18 mm to 2.35 mm, and the bulk density is 65 kg / m2. .

[0025] Example 1 A phase change temperature regulating wall includes phase change concrete, wherein the phase change concrete is composed of the following components in parts by mass: 30-50 parts of phase change lightweight aggregate, 20-30 parts of gravel, 15-20 parts of sulphoaluminate cementitious material, 10-20 parts of water; The phase change lightweight aggregate is prepared by combining expanded perlite with phase change material paraffin, and the particle size of the phase change lightweight aggregate is 2.35mm-5mm; The sulphoaluminate cementitious material comprises: 40-50 parts of sulphoaluminate cement, 10-20 parts of ordinary Portland cement, 5-10 parts of desulfurized building gypsum, 20-35 parts of mineral powder, and 0.1-0.5 parts of water reducing agent.

[0026] like Figure 1 As shown in the figure, a method for preparing phase change lightweight aggregate is given.

[0027] The method for preparing phase change lightweight aggregate comprises the following steps: 1) Sieve the expanded perlite with a particle size distribution of 1.18mm-2.35mm, mix 25-33.3 parts by mass of the expanded perlite with 66.7-75 parts by mass of paraffin wax, and place it in a vacuum oven at a vacuum degree of 10 -4 Vacuum impregnation for 3 h to 8 h under the conditions of Pa and 40 ° C to 60 ° C to prepare a composite phase change material; 2) Screen the composite phase change material with a particle size distribution of 1.18mm-2.35mm, add it into the granulator in proportion, and add 20%-30% of the mass of the composite phase change material into water for pre-wetting; 3) Add sulphoaluminate cementitious material and water in proportion to form a phase change lightweight aggregate with a particle size distribution of 2.35mm-5mm.

[0028] After testing, the leakage of phase change lightweight aggregate is less than 0.5%.

[0029] In step 1), the expanded perlite is added to the blender, the liquid paraffin is poured in, and the mixture is slowly stirred at a speed of 140 r / min for 40 seconds to achieve uniform mixing.

[0030] Expanded perlite and paraffin were mixed in a mass ratio of 1:2 to prepare a composite phase change material. The bulk density of the composite phase change material was 217.8 kg / , water absorption rate 113.3%, phase change latent heat 122J / g; 1:3 composite phase change material bulk density 307kg / , water absorption rate 44%, phase change latent heat 143J / g.

[0031] In step 2), composite phase change materials of different particle sizes will affect the granulation effect. When there is a large amount of fine powder below 1.18 mm in the composite phase change material, the powder will agglomerate into large lumps during the granulation process, affecting the uniformity of the aggregate and the coating effect of the cementitious material. Therefore, composite phase change materials with similar particle sizes and the same gradation are selected for preparation.

[0032] The primary goal of this embodiment is to produce fine aggregates smaller than 5 mm, so a composite phase change material with a particle size distribution of 1.18 mm to 2.35 mm is selected. In other optional embodiments, if the goal is to produce coarse aggregates with a particle size distribution greater than 5 mm, expanded perlite with a particle size greater than 5 mm can also be used to prepare a composite phase change material with a particle size greater than 5 mm, and then to prepare a phase change lightweight aggregate.

[0033] In this embodiment, limiting the particle size of the phase-change lightweight aggregate to 2.35mm-5mm is a key feature in achieving the structural layer's functionality. When applied to phase-change concrete, the smaller particle size allows for more even dispersion in the concrete, forming a dense structure with the gravel and cementitious materials. This results in higher compressive strength after curing, allowing for direct use as an exterior wall structural layer.

[0034] In addition, 2.35mm-5mm phase-change lightweight aggregate is selected to form a complementary gradation with the coarse aggregate when preparing phase-change concrete. Small-size aggregate can fill the gaps between coarse aggregates such as gravel, and then through the bonding effect of cementitious materials, the internal pores of the concrete are reduced, forming a dense structure of coarse aggregate skeleton, fine aggregate filling and cementitious material bonding. Grading design is one of the core reasons to ensure the high compressive strength of phase-change concrete.

[0035] It should be pointed out that the use of 2.35mm-5mm phase change lightweight aggregate has a larger specific surface area and more complete contact with the cementitious material. The cementitious material can evenly wrap the surface of the phase change lightweight aggregate and penetrate to the edge of the pores to form a dense sealed shell.

[0036] The use of phase-change lightweight aggregate with a diameter of 2.35mm-5mm ensures optimal compatibility with the subsequent construction process of the resulting phase-change concrete, making it suitable for prefabricated modular structural layers. The 2.35mm-5mm phase-change lightweight aggregate has improved fluidity, allowing it to evenly fill the mold during the casting of prefabricated wall panels, avoiding the uneven casting and air bubbles caused by oversized particles. Furthermore, the uniform particle size ensures consistent performance across all wall panels, ensuring balanced stress distribution throughout the assembled phase-change thermostatic wall.

[0037] In step 3), the leakage amount is detected by wrapping the phase-change lightweight aggregate with filter paper, baking it in a high-temperature oven at 45 degrees Celsius for 24 hours, and then taking it out. The mass change of the filter paper is weighed to determine the amount of paraffin seeping from the aggregate and calculate it.

[0038] Phase change lightweight aggregate was prepared according to the ratio of 17 parts by mass of composite phase change material, 65 parts by mass of sulphoaluminate cementitious material and 18 parts by mass of water. The leakage of the obtained phase change lightweight aggregate was only 0.36%.

[0039] The composite phase change material has a phase change latent heat of 100J / g-160J / g and excellent heat storage performance. The obtained phase change lightweight aggregate has a phase change latent heat of 20J / g-30J / g.

[0040] The phase-change lightweight aggregate is prepared by the phase-change lightweight aggregate preparation method as described above.

[0041] In this embodiment, the obtained lightweight aggregate is composed of the following components by mass: 15 parts of composite phase change material, 70 parts of sulphoaluminate cementitious material, and 15 parts of water. After testing, the leakage of the obtained phase change lightweight aggregate is only 0.1%; the bulk density is 960kg / , the 28d cylinder pressure strength can reach 8.3MPa.

[0042] A phase change temperature regulating wall utilizes the phase change lightweight aggregate prepared above.

[0043] A phase change temperature regulating wall adopts phase change concrete, wherein the phase change concrete is composed of the following components in parts by mass: 30-50 parts of the phase change lightweight aggregate prepared in Example 1, 20-30 parts of gravel, 15-20 parts of sulphoaluminate cementitious material, and 10-20 parts of water are used; The sulphoaluminate cementitious material includes: 40-50 parts of sulphoaluminate cement, 10-20 parts of ordinary Portland cement, 5-10 parts of desulfurized building gypsum, 20-35 parts of mineral powder, and 0.1-0.5 parts of water reducing agent.

[0044] In addition, phase change concrete is combined with an anti-cracking layer, a steel mesh connection layer, and a foam insulation layer to form a wall panel. Through the combined construction of the wall panels, a phase change temperature-regulating wall is obtained, which can cause the internal phase change lightweight aggregate to undergo phase change under the action of solar energy to resist temperature changes.

[0045] The preparation method of the phase change temperature regulating wall comprises the following steps: soaking the phase change lightweight aggregate, removing the water after saturation and draining it to obtain pre-wetted phase change lightweight aggregate; Sulphoaluminate cement, ordinary Portland cement, desulfurized building gypsum, mineral powder and water reducing agent are mixed in proportion to obtain a mixed powder; Add water to the mixed powder and stir to form a slurry. Add stones and pre-wetted phase change lightweight aggregate into the slurry, continue stirring until evenly mixed, and then pour it into the mold; After initial setting, the anti-cracking layer, steel mesh connection layer and foam insulation layer are filled to form wall panels, and the phase change temperature control wall is obtained by combining the wall panels.

[0046] Specifically, they include: 1) Soak the prepared phase change lightweight aggregate in water for 2 hours to make it saturated with water, then drain the surface water for later use; 2) Mix the powder materials except phase change lightweight aggregate and gravel in the above formula evenly and add them into the mixer; 3) Add water and stir for 2-3 minutes to form a slurry; 4) Add gravel and pre-wetted phase change lightweight aggregate, continue stirring for 2-3 minutes, and pour into the mold; 5) After initial setting, fill in the anti-cracking layer, steel mesh connection layer, foam insulation layer, etc. to form a wall panel for phase change temperature control wall.

[0047] Among them, the sulphoaluminate cementitious material in this embodiment adopts a composite formula of 40-50 parts of sulphoaluminate cement and 10-20 parts of ordinary Portland cement. Through the synergistic effect of the two cements, it not only retains the characteristics of rapid hardening and early strength of sulphoaluminate cement, but also optimizes the later strength stability through ordinary Portland cement, while reducing the leakage risk of phase change material.

[0048] The sulphoaluminate cement in this embodiment is solid waste-based sulphoaluminate cement, which forms a composite system with silicate cement, by-product desulfurized building gypsum, and mineral powder. Figure 2 As shown, Figure 2 (a) and Figure 2 (b) Both structures show that the large amount of needle-shaped ettringite (Etrringite) produced by the hydration of sulfoaluminate cement forms a strong skeleton structure, providing excellent mechanical properties. Meanwhile, the calcium silicate hydrate (CSH) colloid formed by the hydration of ordinary Portland cement fills the pores of the skeleton, further compacting the structure. This crystal-colloid composite system provides aggregate strength and efficient encapsulation, preventing leakage of the phase change material. The addition of by-products such as desulfurized building gypsum and mineral powder not only consumes accumulated solid waste and improves environmental benefits, but also synergistically enhances the early strength and rapid setting properties, improving construction and production efficiency and shortening the production cycle.

[0049] In addition, the BSE diagram and energy spectrum line scan results of the aggregate formed by the sulphoaluminate cementitious material are as follows: Figure 3 As shown. Figure 3 As shown, Figure 3 (a) and Figure 3 (b) shows the microstructure of the expanded perlite and cementitious shell of the aggregate core captured by BSE. Figure 3 (c) shows the energy spectrum line scan results. Near the interface transition zone between expanded perlite and the aggregate shell, the CO element curve near the expanded perlite side shows a high fit, indicating that the paraffin is concentrated in this area. However, after entering the aggregate shell, the CO element curve fit gradually decreases until there is no significant fit. This indicates that the shell structure formed by the hydration of the sulphoaluminate cementitious material intercepts the paraffin, providing a good anti-leakage effect.

[0050] Comparative Example 1: A phase change temperature regulating wall is different from Example 1 in that the phase change lightweight aggregate is not encapsulated and granulated using sulphoaluminate gelling material.

[0051] If the composite phase change material is not wrapped, the composite phase change material prepared by mixing 33.3 parts by mass of expanded perlite and 66.7 parts by mass of paraffin is baked for 24 hours. After testing, the leakage of the phase change lightweight aggregate can reach 43.9%.

[0052] Example 2 A phase change temperature regulating wall is made of the phase change lightweight aggregate obtained in Example 1, and the weight of each component thereof is as follows: 2.8kg phase change lightweight aggregate, 1.8kg gravel, 2.8kg sulphoaluminate cement, 1kg ordinary Portland cement, 0.7kg desulfurized building gypsum, 1.2kg mineral powder, 30g water reducer.

[0053] In this embodiment, the preparation method of the phase change temperature regulating wall is as follows: 1) Soak 2.8 kg of the prepared phase change lightweight aggregate in water for 2 hours to make it saturated with water. Drain the surface water after taking it out and set aside; 2) Mix 2.8kg of sulphoaluminate cement, 1kg of ordinary Portland cement, 0.7kg of desulfurized building gypsum, 1.2kg of mineral powder, and 30g of water reducer evenly, and add to the mixer; 3) Add water and stir for 2-3 minutes to form a slurry; 4) Add 1.8kg of gravel and pre-wetted phase-change lightweight aggregate, continue stirring for 2-3 minutes, and pour into the mold; 5) After the initial setting, fill the anti-cracking layer, steel mesh connection layer, foam insulation layer, etc. to form the phase change solar temperature control wall exterior panel.

[0054] After the mold is assembled, the test block is made. The compressive strength of the test block can reach 48MPa at 28 days, the flexural strength is 8MPa, and the overall density is 1432kg / , can be used as the exterior wall structural layer.

[0055] The resulting wall panels were combined to form a phase-change temperature-regulating wall. A sample room constructed using this wall exhibited reduced temperature fluctuations compared to a standard room, with the maximum temperature reduced by 1.3°C and the minimum temperature increased by 2.5°C, even without the air conditioning system. With the air conditioning system active, the temperature remained stable throughout the day, fluctuating by less than 1%. Despite fluctuations in ambient temperature, the indoor temperature and humidity fluctuated by less than 2% throughout the day, with a minimum of 25.7°C and a maximum of 26.1°C. This maintained a stable temperature within a comfortable range, further improving indoor thermal comfort and helping to maintain a constant temperature.

[0056] Unlike the phase-change insulation materials used for thermal bridges in existing technologies, this material is added to foam concrete as an insulation layer. As an insulation layer, foam concrete itself does not have high mechanical properties, but it still has certain strength requirements. A moderate increase in strength also helps stabilize the thermal bridge connection nodes. Therefore, considering insulation and phase-change heat storage, it is also considered to increase the strength of the aggregate to improve its strength as an insulation layer. Furthermore, its application scenario is thermal bridges, that is, the nodes where metal connectors such as rebar and steel mesh are located in buildings. The thermal conductivity of these parts is significantly higher than that of building materials such as cement and mortar, resulting in concentrated heat loss. There is a significant difference in thermal bridge losses between winter and summer. Existing technologies focus on areas in North China, such as Shandong. In these areas, the temperature difference between indoors and outdoors can reach as much as 30°C in winter due to the presence of heating, while in summer the temperature difference is only around 10°C. Therefore, thermal bridge losses are more severe in winter. According to research, the temperature of the thermal bridge area is mostly around 10°C in winter. Therefore, in the existing technology, octanoic acid with a phase change temperature of around 10°C is selected as the phase change material to reduce the loss of the thermal bridge.

[0057] In this embodiment, the application scenario of phase-change lightweight aggregate is the structural layer concrete as a phase-change temperature-regulating wall, in which the main strength of the concrete comes from the gravel. When the concrete strength itself is sufficiently high, the phase-change lightweight aggregate is considered to have a higher heat storage capacity in the phase-change temperature-regulating wall, so that the structural layer also has a certain degree of thermal insulation capacity, achieving the functions of thermal insulation, protection, and structural integration. Therefore, in this embodiment, the prepared phase-change lightweight aggregate does not focus on strength, but instead increases the dosage of phase-change material to improve the heat storage performance of concrete.

[0058] In addition, the scenario that can be used in this embodiment is the wall, so that the structural layer is different from the insulation layer. The location of the structural layer is inside the insulation layer, closer to the room, and closer to the indoor temperature. Therefore, adding more phase change lightweight aggregate to the phase change temperature control wall can play a role in regulating the indoor temperature and improving indoor comfort. The indoor human comfort temperature is 25°C. Therefore, in this embodiment, 25-degree paraffin is selected as the phase change material to slow down the indoor temperature fluctuations so that the indoor temperature can be stabilized at around 25°C. At the same time, in winter and summer, it can also reduce the HVAC energy consumption to maintain the indoor temperature within a comfortable range.

[0059] Example 3 A phase change temperature control wall, the components of which are of the following quality: 3.2 kg phase-change lightweight aggregate, 1.2 kg gravel, 2.45 kg sulphoaluminate cement, 0.8 kg ordinary Portland cement, 0.6 kg desulfurized building gypsum, 1.4 kg mineral powder, 30 g water reducer. The phase-change lightweight aggregate obtained in Example 1 was used.

[0060] In this embodiment, the preparation method of the phase change temperature regulating wall is as follows: 1) Soak 3.2 kg of the prepared phase change lightweight aggregate in water for 2 hours to make it saturated with water. Drain the surface water after taking it out and set aside; 2) Mix 2.45kg of sulphoaluminate cement, 0.8kg of ordinary Portland cement, 0.6kg of desulfurized building gypsum, 1.4kg of mineral powder, and 30g of water reducer, and add them to the mixer; 3) Add water and stir for 2-3 minutes to form a slurry; 4) Add 1.8kg of gravel and pre-wetted phase-change lightweight aggregate, continue stirring for 2-3 minutes, and pour into the mold; 5) After initial setting, fill in the anti-cracking layer, steel mesh connection layer, foam insulation layer, etc. to form wall panels, and use the combination of wall panels to obtain a phase change temperature control wall.

[0061] After the mold is assembled, the test block is made. The obtained test block has a 28d compressive strength of 33MPa, a flexural strength of 6.2MPa, and an overall density of 1382kg / , can be used as the exterior wall structural layer.

[0062] Example 4 A phase change temperature control wall, the components of which are of the following quality: 2kg phase-change lightweight aggregate, 2.2kg gravel, 2.8kg sulphoaluminate cement, 1kg ordinary Portland cement, 0.7kg desulfurized building gypsum, 1.2kg mineral powder, 30g water reducer. The phase-change lightweight aggregate obtained in Example 1 was used.

[0063] In this embodiment, the preparation method of the phase change temperature regulating wall is as follows: 1) Soak 2 kg of the prepared phase change lightweight aggregate in water for 2 hours to make it saturated with water. Drain the surface water and set aside; 2) Mix 2.8kg of sulphoaluminate cement, 1kg of ordinary Portland cement, 0.7kg of desulfurized building gypsum, 1.2kg of mineral powder, and 30g of water reducer evenly, and add to the mixer; 3) Add water and stir for 2-3 minutes to form a slurry; 4) Add 2.2kg of gravel and pre-wetted phase-change lightweight aggregate, continue stirring for 2-3 minutes, and pour into the mold; 5) After initial setting, fill in the anti-cracking layer, steel mesh connection layer, foam insulation layer, etc. to form wall panels, and use the combination of wall panels to obtain a phase change temperature control wall.

[0064] After the mold is assembled, the test block is made. The obtained test block has a 28d compressive strength of 54MPa, a flexural strength of 8.7MPa, and an overall density of 1638kg / , can be used as the exterior wall structural layer.

[0065] Comparative Example 2: A phase change temperature control wall is provided, which differs from Example 2 in that the same volume of expanded perlite / composite phase change material (200g expanded perlite / 600g composite phase change material) is used to replace the phase change lightweight aggregate in the components of the phase change temperature control wall.

[0066] A phase change temperature control wall was prepared according to the preparation method of the phase change temperature control wall. The obtained test blocks had a 28d compressive strength of 18 MPa and 21 MPa, and a flexural strength of 1.3 MPa and 1.8 MPa.

[0067] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A phase change temperature control wall, characterized in that: Including phase change concrete, the phase change concrete is composed of the following components in parts by mass: 30-50 parts of phase change lightweight aggregate, 20-30 parts of gravel, 15-20 parts of sulphoaluminate cementitious material, 10-20 parts of water; The phase change lightweight aggregate is prepared by combining expanded perlite with phase change material paraffin, and the particle size of the phase change lightweight aggregate is 2.35mm-5mm; The sulphoaluminate cementitious material comprises: 40-50 parts of sulphoaluminate cement, 10-20 parts of ordinary Portland cement, 5-10 parts of desulfurized building gypsum, 20-35 parts of mineral powder, and 0.1-0.5 parts of water reducing agent.

2. The phase change temperature control wall according to claim 1, characterized in that: The preparation method of the phase change lightweight aggregate comprises: Expanded perlite absorbs phase change material paraffin to obtain a composite phase change material; The composite phase change material and the cementitious material are mixed and granulated to obtain a phase change lightweight aggregate with a particle size of 2.35 mm to 5 mm.

3. The phase change temperature control wall according to claim 2, characterized in that: The expanded pearlite adsorbing phase change material paraffin comprises: 25-33.3 parts by mass of expanded perlite and 66.7-75 parts by mass of paraffin are mixed and impregnated.

4. The phase change temperature control wall according to claim 3, characterized in that: The impregnation is performed by vacuum impregnation for 3 hours to 8 hours under negative pressure and 40° C. to 60° C.

5. The phase change temperature regulating wall according to any one of claims 2 to 4, characterized in that: The particle size of the expanded perlite is 1.18 mm to 2.35 mm, and the gelling material is sulphoaluminate gelling material.

6. The phase change temperature control wall according to claim 5, characterized in that: The granulation comprises: Screening the composite phase change material with a particle size distribution of 1.18 mm to 2.35 mm and adding it to the granulator; Phase change lightweight aggregate is obtained through a granulator.

7. The phase change temperature control wall according to claim 6, characterized in that: When adding the composite phase change material into the granulator, 20%-30% of the mass of the composite phase change material is added for pre-wetting.

8. The phase change temperature control wall according to claim 1, characterized in that: The phase change concrete is combined with an anti-cracking layer, a steel mesh connection layer, and a foam insulation layer to form a wall panel.

9. A method for preparing a phase change temperature regulating wall according to any one of claims 1 to 8, characterized in that: The following steps are involved: soaking the phase change lightweight aggregate, removing the water after saturation and draining it to obtain pre-wetted phase change lightweight aggregate; Sulphoaluminate cement, ordinary Portland cement, desulfurized building gypsum, mineral powder and water reducing agent are mixed in proportion to obtain a mixed powder; Add water to the mixed powder and stir to form a slurry. Add stones and pre-wetted phase change lightweight aggregate into the slurry, continue stirring until evenly mixed, and then pour it into the mold; After initial setting, the anti-cracking layer, steel mesh connection layer and foam insulation layer are filled to form wall panels, and the phase change temperature control wall is obtained by combining the wall panels.

10. The method for preparing a phase change temperature regulating wall according to claim 9, wherein: The prepared phase change lightweight aggregate is soaked in water for 2 hours, the mixed powder is added with water and stirred for 2 minutes to 3 minutes, and the slurry is added with gravel and pre-wetted phase change lightweight aggregate and stirred for another 2 minutes to 3 minutes.

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