PVC pipeline based on phase change energy storage and preparation method
By designing a multi-layer structure within the PVC pipe and using composite phase change materials and thermally conductive reinforcing materials, the problem of insufficient thermal energy storage capacity of traditional PVC pipes is solved, achieving efficient integration of thermal energy storage and fluid transportation, and improving the stability and efficiency of the system.
Patent Information
- Application Number
- CN202512030495.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-30
- Publication Date
- 2026-03-20
AI Technical Summary
Traditional PVC pipes lack thermal energy storage capacity, resulting in low energy utilization efficiency and unstable system performance. Furthermore, existing methods of introducing phase change materials suffer from problems such as leakage, poor interfacial compatibility, low thermal conductivity, and difficulty in filling.
Employing a multi-layer structure design, MAH-g-PE grafts are added to the PVC matrix. Using composite phase change materials, nanoporous silica powder, and graphene, a phase change energy storage layer is formed inside the PVC pipe through vacuum encapsulation technology, which improves the interfacial bonding strength and thermal conductivity, and simplifies the filling process.
It integrates fluid transport and thermal energy storage, improves energy storage efficiency and structural stability, reduces system complexity and cost, avoids leakage and interface delamination of phase change materials, and improves heat transfer efficiency.
Smart Images
Figure CN121701710A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of pipe manufacturing technology, and more specifically, to a PVC pipe based on phase change energy storage and its preparation method. Background Technology
[0002] PVC pipes are widely used in fluid transportation due to their advantages such as lightweight, low cost and strong corrosion resistance. However, traditional PVC pipes lack thermal energy storage capacity: they can only passively transport fluids and cannot store thermal energy (such as solar thermal, geothermal thermal or waste heat), resulting in low energy utilization efficiency and large fluctuations in system performance when the heat source is unstable. To address this issue, some approaches currently employ additional, independent energy storage devices, but these increase system complexity, cost, and space requirements. Other attempts involve introducing phase change materials (PCMs) into PVC pipes, but this method currently has several drawbacks and cannot be used on a large scale. Firstly, PCM is liquid during the phase change process, exhibiting high fluidity and a tendency to leak. Secondly, PCM has poor interfacial compatibility with the PVC matrix, resulting in weak intermolecular forces and a tendency for interfacial delamination under long-term thermal cycling, reducing pipe structural integrity and heat transfer efficiency. Thirdly, PCM's low thermal conductivity leads to slow heat storage / release rates, failing to meet real-time heat supply and demand balance. Fourthly, due to the narrow and elongated hollow structure of PVC pipes, PCM struggles to fill the PVC cavities, thus requiring urgent improvement. Summary of the Invention
[0003] The purpose of this invention is to overcome the shortcomings of the prior art and provide a PVC pipe based on phase change energy storage and its preparation method. The PVC pipe achieves the integration of fluid transportation and thermal energy storage through multi-layer structural design, material modification and special process, thereby improving energy storage efficiency and structural stability, simplifying system design and reducing costs.
[0004] To achieve the above objectives, the present invention adopts the following technical solution: a PVC pipe based on phase change energy storage, comprising a pipe body, the pipe body comprising a PVC matrix, an energy storage filler and an insulation layer, the PVC matrix comprising an extruded inner matrix layer, an outer matrix layer and connecting ribs, the inner matrix layer and the outer matrix layer being connected by multiple connecting ribs, multiple cavities being provided between the inner matrix layer and the outer matrix layer, adjacent cavities being separated by connecting ribs, the energy storage filler filling the cavities to form a phase change energy storage layer, and the insulation layer being fixed to the outside of the outer matrix layer; The PVC matrix raw material contains 3wt% MAH-g-PE graft material; The energy storage filler includes composite phase change material, shaping material, and thermally conductive reinforcing material. Furthermore, the composite phase change material is a mixture of paraffin and butyl stearate, with a mass ratio of paraffin to butyl stearate of 7:3; the shaping material is nanoporous silica powder with a porosity of 82%-85%, and the amount added is 5 wt% of the mass of the composite phase change material; the thermal conductivity enhancement material is graphene, and the amount added is 10 wt% of the total mass of the composite phase change material.
[0005] Furthermore, the particle size of the shaping material is 10μm-50μm, and the pore size is 20nm-50nm.
[0006] Furthermore, sealing elements are fixed at both ends of the pipe body. Each sealing element includes a base, an annular rib, a plug, and multiple slits. The base abuts against the end of the pipe body. The annular rib is located at one end of the base and is sleeved on the outside of the pipe body. The inner wall of the annular rib is in a sealing fit with the outer wall of the pipe body. The plug is located at one end of the base and is inserted into the inner wall of the base layer. The plug is in a sealing fit with the inner wall of the base layer. The slits are located inside the base. Each slit corresponds to a cavity and can communicate with the cavity.
[0007] Furthermore, the annular rib is externally fixed with a clamp, and the end of the plug is provided with a groove.
[0008] A method for preparing a PVC pipe based on phase change energy storage includes the following steps: S1. Preparation of PVC matrix: PVC resin, 3wt% MAH-g-PE graft, calcium-zinc stabilizer and lubricant are mixed evenly, put into screw extruder to melt, extruded through extrusion die, sized, cooled and cut to form PVC matrix; S2. Insulation layer coating: A polyurethane insulation coating is applied to the outer wall of the PVC substrate, and after curing, an insulation layer is formed on the surface of the PVC substrate; S3. Preparation of energy storage filler: ① Inject nanoporous silica powder into a vacuum impregnation device, draw a vacuum, and inject molten composite phase change material. Impregnation time is 30-60 minutes. ② Inject 10wt% graphene into a vacuum impregnation device, stir evenly, and obtain the energy storage filler; S4. Assemble the PVC substrate: Fix the two silicone seals to both ends of the PVC substrate respectively, and fix the seals to the PVC substrate with clamps. The cuts of the seals correspond one-to-one with the cavities. S5, Vacuum extraction of PVC substrate: ① Connect the connector in the packaging device that is connected to the vacuum equipment to one end of the PVC substrate. Insert the inserts of the connector into the cutouts of the seal to make the connector communicate with the cavity. ② Use a vacuum pump to evacuate the cavity. After evacuation, separate the connector between the PVC substrate and the vacuum pump, close the opening, and the cavity will be in a vacuum state. S6, Vacuum Packaging: ① Connect the connector in the packaging device that is connected to the vacuum impregnation equipment to one end of the PVC substrate. Insert the inserts of the connector into the cutouts of the seal to make the connector communicate with the cavity in the vacuum state. ② Heat the energy storage packing to 60℃ to melt it. The energy storage packing in the vacuum impregnation equipment is injected into the annular cavity in a vacuum environment through the insert of the connector until it is completely filled. ③ Separate the connectors connecting the PVC substrate to the vacuum impregnation equipment, close the cut, and place the energy storage filler inside the cavity to complete the encapsulation of the energy storage filler; S7. Gradient cooling treatment: The encapsulated pipe body is placed in a temperature control device and cooled from 60°C to 25°C at a rate of 5°C / min to solidify the energy storage filler and eliminate internal stress. S8. Complete the preparation of the main pipe body. Furthermore, in step S3, the nanoporous silica powder needs to be vacuum dried at 105°C for 2 hours before use.
[0009] Furthermore, in step S5, the pressure inside the cavity is pumped down to 0.09MPa-0.095MPa.
[0010] Furthermore, the packaging device also includes a fixing frame. In use, the pipe body passes through the fixing frame and is clamped by the clamp at the upper end of the fixing frame so that the pipe body is in an inclined state. The connectors that connect to the vacuum pumping equipment can be connected to the highest end of the pipe body, and the connectors that connect to the vacuum impregnation equipment can be connected to the lowest end of the pipe body.
[0011] Furthermore, the connector includes a connector head, a joint is connected to the side of the connector head, a limiting groove is provided at the end of the connector head, the sealing element can be inserted into the limiting groove, an insert is provided at the bottom of the limiting groove, the insert corresponds one-to-one with the cut, the insert can be inserted into the cut and open the cut, and a through hole is provided inside the insert, the through hole communicates with the joint.
[0012] In summary, the present invention has the following beneficial effects: 1. The PVC matrix raw material contains 3wt% maleic anhydride-grafted polyethylene MAH-g-PE. The maleic anhydride groups in the MAH-g-PE molecule can form hydrogen bonds with the ester groups of butyl stearate in the energy storage filler, which significantly improves the interfacial bonding strength between the PVC matrix and the energy storage filler, avoids interfacial peeling under long-term thermal cycling, and thus improves the integrity of the pipeline structure and heat transfer efficiency. 2. Nanoporous silica powder forms a "support skeleton" in the energy storage filler. Its three-dimensional network porous structure physically traps and shapes the molten composite phase change material through capillary adsorption, reducing the fluidity of the composite phase change material in the molten state. This effectively reduces leakage of the molten composite phase change material. After solidification, it forms a solid-like structure with high compressive strength, providing a stable carrier for the bonding of the composite phase change material with the PVC matrix, thereby further improving the interfacial bonding strength between the PVC matrix and the energy storage filler. 3. Graphene forms a continuous thermally conductive network in the energy storage filler, effectively improving the thermal conductivity of the energy storage filler, thereby increasing its heat storage and release rate. 4. By using a vacuum sealing process, the air pressure resistance in the cavity is eliminated in a vacuum environment, allowing the molten energy storage filler to fill rapidly under the action of pressure difference. The main body of the pipeline is set at a 30° angle and the filler is injected from the lowest end. Gravity is used to achieve the filling of the energy storage filler from bottom to top, which effectively avoids the generation of air bubbles, resulting in a high filling rate and improved energy storage efficiency. After filling is completed, the cut closes naturally without the need for additional sealing operations. This simplifies the process and, by utilizing the elastic sealing properties of silicone parts, prevents leakage of the energy storage filler during the transportation of the pipeline. Attached Figure Description
[0013] Figure 1 This is a cross-sectional view of the main body of the pipeline; Figure 2 This is a cross-sectional view of the assembled pipe body and sealing components. Figure 3 This is a schematic diagram of the assembled pipe body and sealing components. Figure 4 for Figure 3 A partial sectional view; Figure 5 This is a schematic diagram of the packaging device. Figure 6 This is a structural schematic diagram of the connector; Figure 7 This is a sectional view of the connector.
[0014] Reference numerals: 1. PVC substrate; 11. Inner layer of substrate; 12. Outer layer of substrate; 13. Connecting rib; 14. Cavity; 2. Energy storage filler; 3. Insulation layer; 4. Sealing element; 41. Circular rib; 42. Plug; 43. Groove; 44. Cutout; 45. Base; 5. Clamp; 6. Vacuum impregnation equipment; 61. Mounting base; 7. Vacuum pumping equipment; 71. Solenoid valve; 8. Connector; 81. Connector head; 82. Limiting groove; 83. Insert; 84. Through hole; 85. Joint; 9. Fixing bracket; 91. Clamping plate; 100. Pipe body. Detailed Implementation
[0015] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. 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.
[0016] like Figures 1 to 7 As shown, this embodiment discloses a PVC pipe based on phase change energy storage, including a pipe body 100, which includes a PVC matrix 1, an energy storage filler 2, and an insulation layer 3.
[0017] like Figure 1 As shown, the PVC matrix 1 includes an extruded inner matrix layer 11, an outer matrix layer 12, and connecting ribs 13. The inner matrix layer 11 and the outer matrix layer 12 are connected by multiple connecting ribs 13. Multiple cavities 14 are provided between the inner matrix layer 11 and the outer matrix layer 12. Adjacent cavities 14 are separated by connecting ribs 13. By setting connecting ribs 13, the structural strength of the entire PVC matrix 1 can be improved. Four connecting ribs 13 are arranged axially, thus forming four cavities 14. The cavities 14 are arranged in a fan shape. The energy storage filler 2 fills the cavities 14 and contacts the PVC matrix 1 to form a phase change energy storage layer.
[0018] The PVC matrix 1 contains 3 wt% maleic anhydride-grafted polyethylene (MAH-g-PE). The maleic anhydride groups in the MAH-g-PE molecules can form hydrogen bonds with the ester groups of butyl stearate in the energy storage filler 2, which significantly improves the interfacial bonding strength between the PVC matrix 1 and the energy storage filler 2, avoids interfacial peeling under long-term thermal cycling, and thus improves the integrity of the pipeline structure and the heat transfer efficiency.
[0019] Energy storage filler 2 includes composite phase change material, shaping material and thermally conductive reinforcing material; The composite phase change material is a mixture of paraffin wax and butyl stearate, with a mass ratio of 7:3. The melting point range of paraffin wax is 47℃-68℃, and the melting point range of butyl stearate is 20℃-28℃. When the two are mixed in a 7:3 ratio, the melting point range of the mixture is 28℃-42℃. This melting point range is suitable for energy storage of solar thermal, geothermal, or waste heat.
[0020] The shaping material is nanoporous silica powder with a porosity of 82%-85%, a particle size of 10μm-50μm, and a pore size of 20nm-50nm. The addition amount is 5wt% of the composite phase change material. The nanoporous silica powder forms a "support skeleton" in the energy storage filler 2. Its three-dimensional network porous structure physically traps and shapes the molten composite phase change material through the principle of capillary adsorption, reducing the fluidity of the composite phase change material in the molten state, thereby effectively reducing the leakage of the composite phase change material after melting. After solidification, it forms a solid-like structure with high compressive strength, providing a stable carrier for the bonding of the composite phase change material and the PVC matrix 1, thereby further improving the interfacial bonding strength between the PVC matrix 1 and the energy storage filler 2.
[0021] The thermal conductivity enhancement material is graphene, which is added at 10 wt% of the total mass of the composite phase change material. Graphene forms a continuous thermally conductive network in the energy storage filler 2, which effectively improves the thermal conductivity of the energy storage filler 2, thereby increasing its heat storage and heat release rate.
[0022] The insulation layer 3 is fixed to the outside of the outer layer 12 of the substrate. The polyurethane insulation coating is sprayed onto the surface of the PVC substrate 1 by a spraying device. After curing, the insulation layer 3 is formed. The thickness of the insulation layer 3 is 2mm-3mm. The insulation layer 3 can not only insulate the inside of the pipe body 100, but also protect the pipe body 100 and improve the weather resistance of the pipe body 100.
[0023] The energy storage filler 2 needs to be injected into the cavity 14 through vacuum sealing, so the two ends of the PVC matrix need to be blocked by the sealing element 4.
[0024] like Figures 2 to 4 As shown, sealing elements 4 are fixed at both ends of the pipe body 100. The sealing elements 4 are silicone parts. The sealing elements 4 include a base 45, an annular rib 41, a plug 42, and multiple cuts 44. The base 45 abuts against the end of the pipe body 100. The annular rib 41 is located at one end of the base 45 and is sleeved on the outside of the pipe body 100. The inner wall of the annular rib 41 is sealed to the outer wall of the pipe body 100. The plug 42 is located at one end of the base 45 and is inserted into the inner wall of the inner layer 11 of the base. The plug 42 is sealed to the inner wall of the inner layer 11 of the base. The end of the plug 42 is provided with a groove 43. The groove 43 facilitates the deformation of the end of the plug 42, thereby facilitating the insertion of the plug 42 into the inner wall of the inner layer 11 of the base. Furthermore, the plug 42 is a solid structure and is not easily deformed, resulting in good sealing reliability between the plug 42 and the inner wall of the inner layer 11 of the base.
[0025] The cut 44 is located inside the base 45. The cut 44 corresponds one-to-one with the cavity 14 and can communicate with the cavity 14. The cut 44 closes naturally without external force to ensure the airtightness after vacuum sealing. The height of the cut 44 is 1cm. When the cut 44 is closed, it can withstand greater pressure to prevent the cut 44 from deforming and causing the vacuum inside the cavity 14 to fail when the internal pressure of the cavity 14 is inconsistent with the external pressure, and to prevent the energy storage filler 2 from leaking during transportation.
[0026] The annular rib 41 is externally fixed with a clamp 5. By setting the clamp 5, it can be ensured that the inner wall of the annular rib 41 is tightly fitted with the outer wall of the pipe body 100.
[0027] like Figures 5 to 7 As shown, the energy storage filler 2 and the PVC matrix 1 are encapsulated by an encapsulation device. The encapsulation device includes a vacuum impregnation device 6, a vacuum pumping device 7, a connector 8, and a fixing frame 9. The vacuum impregnation device 6 and the vacuum pumping device 7 are existing technologies. There are two connectors 8. The vacuum impregnation device 6 is connected to one connector 8 through a pipeline, and the connector 8 is fixed to the ground at an angle by a mounting base 61. The vacuum pumping device 7 is connected to another connector 8 via a pipeline. The pipeline is also equipped with a solenoid valve 71 for cutting off or connecting the pipeline. The vacuum pumping device 7 is equipped with a pressure gauge that can display the vacuuming pressure value.
[0028] The fixing frame 9 is used to clamp the pipe body 100. The upper end of the fixing frame 9 is fixed with a clamping plate 91, which is a clamp. Through the clamping plate 91, the pipe body 100 can be tilted and fixed on the fixing frame 9, and the tilt angle is consistent with the tilt angle of the mounting base 61, which is 30°. The connector 8 connected to the vacuum pumping equipment 7 can be connected to the highest end of the pipe body 100, and the connector 8 connected to the vacuum impregnation equipment 6 can be connected to the lowest end of the pipe body 100. By tilting the material from bottom to top, gravity can be used to ensure that the energy storage filler 2 is fully filled and there are no air bubbles.
[0029] The connector 8 includes a connector 81, with a joint 85 connected to its side. The end of the connector 81 is provided with a limiting groove 82, and the sealing member 4 can be inserted into the limiting groove 82 for positioning. The bottom of the limiting groove 82 is provided with a insert 83, which corresponds one-to-one with the cut 44. The insert 83 can be inserted into the cut 44 and open the cut 44, thereby establishing a fluid channel. The insert 83 is provided with a through hole 84 inside, which communicates with the joint 85. The joint 85 of the connector 8 can be connected to the pipeline of the vacuum impregnation equipment 6 or the vacuum pumping equipment 7.
[0030] A method for preparing a PVC pipe based on phase change energy storage includes the following steps: S1, Preparation of PVC matrix 1: PVC resin, 3wt% MAH-g-PE graft, calcium zinc stabilizer and lubricant are mixed evenly, put into screw extruder to melt, extruded through extrusion die, sized, cooled and cut to form PVC matrix 1. During the extrusion process, connecting rib 13, inner layer 11 of matrix and outer layer 12 of matrix are formed simultaneously. S2, Insulation layer 3 coating: The outer wall of the PVC substrate 1 is coated with a polyurethane insulation coating. After curing, the insulation layer 3 is formed on the surface of the PVC substrate 1. The coating thickness is controlled at 2mm-3mm. S3, Preparation of energy storage filler 2: ① Before use, the nanoporous silica powder is vacuum dried at 105℃ for 2 hours to remove moisture and impurities from the pores and ensure adsorption performance. ② Vacuum impregnation: The pretreated nanoporous silica powder is injected into the vacuum impregnation equipment 6, and a vacuum is drawn to remove the air from the pores; ③ Inject the molten composite phase change material at a temperature range of 60℃-70℃ for 30-60 minutes to ensure that the composite phase change material fully fills the silica pores. ④ Inject 10wt% graphene into the vacuum impregnation equipment 6, stir evenly to make the graphene uniformly dispersed and form a continuous heat-conducting network, and obtain the energy storage filler 2. S4. Assemble the PVC substrate 1: Fix the two silicone seals 4 to both ends of the PVC substrate 1 respectively. The base 45 of the seal 4 abuts against the end of the PVC substrate 1. The annular rib 41 is sleeved on the outer wall of the PVC substrate 1. The plug 42 is inserted into the inner wall of the inner layer 11 of the substrate. Rotate the seal 4 to adjust its position to ensure that the cut 44 of the seal 4 corresponds one-to-one with the cavity 14 of the PVC substrate 1. Then fix the seal 4 and the PVC substrate 1 with the clamp 5 to achieve sealing. S5, Vacuuming of PVC substrate 1: ① Pass the pipe body 100 through the clamp 91 at the upper end of the fixing frame 9, and fix it by clamping it with the clamp 91; ② The connector 8 connected to the vacuum equipment 7 in the packaging device is connected to the highest end of the PVC substrate 1, so that the seal 4 is inserted into the limiting groove 82 of the connector 8, and the insert 83 is inserted into the cut 44 of the seal 4 and the cut 44 is opened to establish a communication channel between the connector 8 and the cavity 14. ③ Start the vacuum pumping device 7 and pump the pressure in the cavity 14 to 0.09MPa-0.095MPa, maintain it for 1 minute, and completely remove the air from the cavity 14. After the vacuum is completed, separate the connector 8 from the PVC substrate 1. The cut 44 of the seal 4 will close naturally under the action of elasticity, and the cavity 14 will remain in a vacuum state. S6, Vacuum Packaging: ① Connect the connector 8, which is connected to the vacuum impregnation equipment 6 in the packaging device, to the lowest end of the PVC substrate 1. Insert the insert 83 of the connector 8 into the cut 44 of the seal 4 and open the cut 44 so that the connector 8 is connected to the cavity 14 in the vacuum state, and establish a communication channel between the vacuum impregnation equipment 6 and the cavity 14. ② Heat the energy storage filler 2 to 60°C to melt it. Through the conveying system in the vacuum impregnation equipment 6, the energy storage filler 2 is injected into the cavity 14 through the insert 83 of the connector 8 in a vacuum environment until it is completely filled. With the help of gravity, the energy storage filler 2 fills from the lowest end of the PVC matrix 1 to the highest end until the cavity is filled. During the filling process, the energy storage filler will not overflow from the cut 44 of the highest end seal 4. ③ Turn off the conveying system of the vacuum impregnation equipment 6, separate the connector 8 connecting the PVC matrix 1 and the vacuum impregnation equipment 6, the cut 44 closes naturally, and the energy storage filler 2 is sealed in the cavity 14, thus completing the vacuum sealing of the energy storage filler 2. By using a vacuum sealing process, the air pressure resistance in the cavity 14 is eliminated in a vacuum environment, allowing the molten energy storage filler 2 to be filled rapidly under the action of pressure difference. The pipeline body 100 is set at a 30° angle and the filler is injected from the lowest end. Gravity is used to achieve the filling of the energy storage filler 2 from bottom to top, which effectively avoids the generation of air bubbles, resulting in a high filling rate and improved energy storage efficiency. After filling is completed, the cut 44 closes naturally without the need for additional sealing operations. This simplifies the process and, by utilizing the elastic sealing properties of silicone parts, prevents leakage of the energy storage filler 2 during transportation of the pipeline body 100.
[0031] S7. Gradient cooling treatment: The encapsulated pipe body 100 is placed in a temperature control device and cooled from 60°C to 25°C at a rate of 5°C / min. The gradient cooling eliminates the thermal stress between the energy storage filler 2 and the PVC matrix 1, prevents interface cracking, and allows the energy storage filler 2 to fully cure, ensuring structural stability. S8. Complete the preparation of the main body of the pipeline 100.
[0032] The above description is merely a preferred embodiment of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principles of the present invention should also be considered within the scope of protection of the present invention.
Claims
1. A PVC pipe based on phase change energy storage, characterized in that, The system includes a pipe body (100), which includes a PVC matrix (1), an energy storage filler (2), and an insulation layer (3). The PVC matrix (1) includes an extruded inner matrix layer (11), an outer matrix layer (12), and connecting ribs (13). The inner matrix layer (11) and the outer matrix layer (12) are connected by multiple connecting ribs (13). Multiple cavities (14) are provided between the inner matrix layer (11) and the outer matrix layer (12). Adjacent cavities (14) are separated by connecting ribs (13). The energy storage filler (2) is filled in the cavities (14) to form a phase change energy storage layer. The insulation layer (3) is fixed to the outside of the outer matrix layer (12). The PVC matrix (1) raw material contains 3wt% MAH-g-PE graft material; The energy storage filler (2) includes composite phase change material, shaping material and thermally conductive reinforcing material.
2. A PVC pipe based on phase change energy storage according to claim 1, characterized in that, The composite phase change material is a mixture of paraffin wax and butyl stearate, with a mass ratio of paraffin wax to butyl stearate of 7:
3. The shaping material is nanoporous silica powder with a porosity of 82%-85%, and its addition amount is 5 wt% of the mass of the composite phase change material. The thermal conductivity enhancement material is graphene, and its addition amount is 10 wt% of the total mass of the composite phase change material.
3. A PVC pipe based on phase change energy storage according to claim 2, characterized in that, The particle size of the shaping material is 10μm-50μm, and the pore size is 20nm-50nm.
4. A PVC pipe based on phase change energy storage according to claim 1, characterized in that, The pipe body (100) is fixed with sealing elements (4) at both ends. The sealing element (4) includes a base (45), an annular rib (41), a plug (42) and multiple cuts (44). The base (45) abuts against the end of the pipe body (100). The annular rib (41) is located at one end of the base (45) and is sleeved on the outside of the pipe body (100). The inner wall of the annular rib (41) is sealed to the outer wall of the pipe body (100). The plug (42) is located at one end of the base (45) and is inserted into the inner wall of the inner layer (11) of the base. The plug (42) is sealed to the inner wall of the inner layer (11) of the base. The cuts (44) are located inside the base (45). The cuts (44) correspond one-to-one with the cavities (14) and can communicate with the cavities (14).
5. A PVC pipe based on phase change energy storage according to claim 4, characterized in that, The annular rib (41) is externally fixed with a clamp (5), and the end of the plug (42) is provided with a groove (43).
6. A method for preparing a PVC pipe based on phase change energy storage, used to prepare a PVC pipe based on phase change energy storage as described in any one of claims 1-5, characterized in that, Includes the following steps: S1, PVC matrix (1) preparation: PVC resin, 3wt% MAH-g-PE graft, calcium zinc stabilizer and lubricant are mixed evenly, put into screw extruder to melt, extruded through extrusion die, sized, cooled and cut to form PVC matrix (1); S2, Insulation layer (3) coating: The outer wall of the PVC substrate (1) is coated with a polyurethane insulation coating, and after curing, an insulation layer (3) is formed on the surface of the PVC substrate (1); S3. Preparation of energy storage filler (2): ① Inject nanoporous silica powder into a vacuum impregnation device (6), evacuate, and inject molten composite phase change material for 30-60 minutes. ② Inject 10wt% graphene into the vacuum impregnation equipment (6), stir evenly, and obtain the energy storage filler (2); S4. Assemble the PVC substrate (1): Fix the two silicone seals (4) to both ends of the PVC substrate (1) respectively, and fix the seals (4) and the PVC substrate (1) with clamps (5). The cuts (44) of the seals (4) correspond one-to-one with the cavities (14). S5, PVC substrate (1) Vacuuming; S6, vacuum packaging; S7. Gradient cooling treatment: Place the encapsulated pipe body (100) in a temperature control device and cool it from 60°C to 25°C at a rate of 5°C / min to solidify the energy storage filler (2) and eliminate internal stress. S8. Complete the preparation of the main body of the pipeline (100).
7. The method for preparing a PVC pipe based on phase change energy storage according to claim 6, characterized in that, In step S3, the nanoporous silica powder needs to be vacuum dried at 105°C for 2 hours before use.
8. A method for preparing a PVC pipe based on phase change energy storage according to claim 6, characterized in that, Step S5 also includes: ① Connect the connector (8) in the packaging device that is connected to the vacuum equipment (7) to one end of the PVC substrate (1). Insert the insert (83) of the connector (8) into the cut (44) of the seal (4) so that the connector (8) communicates with the cavity (14). ② The cavity (14) is evacuated by the vacuum equipment (7). After the vacuum is completed, the connector (8) connecting the PVC substrate (1) and the vacuum equipment (7) is separated, the cut (44) is closed, the cavity (14) is in a vacuum state, and the pressure inside the cavity (14) is reduced to 0.09MPa-0.095MPa. Step S6 also includes: ① Connect the connector (8) in the packaging device that is connected to the vacuum impregnation equipment (6) to one end of the PVC substrate (1). Insert the insert (83) of the connector (8) into the cut (44) of the seal (4) so that the connector (8) communicates with the cavity (14) in the vacuum state. ② Heat the energy storage filler (2) to 60°C to melt it, and inject the energy storage filler (2) in the vacuum impregnation equipment (6) into the annular cavity (14) in a vacuum environment through the insert (83) of the connector (8) until it is completely filled; ③ Separate the connector (8) connecting the PVC substrate (1) and the vacuum impregnation equipment (6), close the cut (44), and place the energy storage filler (2) in the cavity (14) to complete the encapsulation of the energy storage filler (2).
9. A method for preparing a PVC pipe based on phase change energy storage according to claim 6, characterized in that, The encapsulation device also includes a fixing frame (9). In use, the pipe body (100) passes through the fixing frame (9) and is clamped by the clamp (91) at the upper end of the fixing frame (9) so that the pipe body (100) is tilted. The connector (8) connected to the vacuum pumping device (7) can be connected to the highest end of the pipe body (100), and the connector (8) connected to the vacuum impregnation device (6) can be connected to the lowest end of the pipe body (100).
10. A method for preparing a PVC pipe based on phase change energy storage according to claim 6, characterized in that, The connector (8) includes a connector (81), a joint (85) is connected to the side of the connector (81), a limiting groove (82) is provided at the end of the connector (81), the sealing element (4) can be inserted into the limiting groove (82), a insert (83) is provided at the bottom of the limiting groove (82), the insert (83) corresponds one-to-one with the cut (44), the insert (83) can be inserted into the cut (44) and open the cut (44), the insert (83) is provided with a through hole (84) inside, and the through hole (84) communicates with the joint (85).