Formula and preparation process of medium-temperature phase-change heat storage material
By optimizing the formulation and preparation process of phase change heat storage materials, the problems of supercooling, phase separation and low thermal conductivity of materials are solved, which significantly improves the performance and life of materials and reduces production costs and energy consumption.
Patent Information
- Application Number
- CN202510323681.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-19
- Publication Date
- 2025-06-20
AI Technical Summary
Existing phase-change heat storage materials have problems such as supercooling, phase separation and low thermal conductivity, which leads to the inability to release latent heat, the number of thermal cycles, and the effective period of materials, which increases the difficulty of system integration and initial investment costs.
By optimizing the material formula, adding bio-based compatible materials to mix multi-composite formulas, the supercooling, phase separation and low thermal conductivity of the materials are solved by using three-dimensional mixer gradient mixing, dynamic press molding, high-density polyethylene plus polypropylene canning, aluminum foil heat sealing and ultrasonic cavitation treatment.
It significantly reduces the supercooling degree, improves the controllability and stability of the phase change process, extends the material cycle life, improves the thermal conductivity, significantly accelerates the storage/heat release rate, and reduces production energy consumption and costs.
Smart Images
Figure CN120173566A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of phase change heat storage materials, and specifically to a medium-temperature phase change heat storage material formula and preparation process. Background Art
[0002] Phase change heat storage materials are an effective way to reduce the dependence on fossil energy and aim to solve the energy supply-demand mismatch caused by the uncertainty and volatility of clean energy. They are defined in the heat storage sub-field of new energy storage and are an effective supplementary means in addition to short-term energy storage such as electrochemical energy storage. Currently, they are an essential link to balance the power grid stability and local consumption of clean energy, and are also an indispensable part of the future transformation of distributed energy to an off-grid operation mode.
[0003] The main disadvantages of current market products are mainly the high supercooling degree, phase separation, and low thermal conductivity caused by the physical properties of the materials. These defects directly affect the application of phase change materials in heating systems, resulting in problems such as latent heat being unable to be released, reducing the number of heat cycles, and shortening the effective cycle of the materials, thereby increasing the system integration difficulty and initial investment cost.
[0004] The existing production system process of phase change materials is relatively complex, especially the front-end melting link. Based on the characteristics of phase change materials, the overall temperature of all production links must be maintained above the melting temperature of the phase change materials to ensure the fluidity of the materials to complete the subsequent canning process. This process has always restricted the development of the entire industry due to complex temperature control, inability to weigh accurately, and huge energy consumption. Summary of the Invention
[0005] (1) Technical Problems to be Solved
[0006] In view of the deficiencies of the prior art, the present invention provides a medium-temperature phase change heat storage material formula and preparation process. By synergistically optimizing and modifying different materials in proportion and adding bio-based compatible materials to prepare a multi-component composite formula, the three major technical bottlenecks and core defects of supercooling, phase separation, and low thermal conductivity of phase change materials are solved, thereby reducing the use cost and increasing the material life. The preparation process solves the problems of inability to fill and accurately weigh during production due to the need to maintain high temperature, and can complete production with relatively low energy consumption, reducing the body feeling temperature and improving the production environment.
[0007] (2) Technical Solutions
[0008] To achieve the above objectives, the present invention is realized through the following technical solutions: A medium-temperature phase change heat storage material formula, the raw materials of which include, by weight: 87%-93% of sodium acetate trihydrate, 0.5%-1.5% of xanthan gum, 4%-6% of nucleating agent, and 3%-4.5% of thermal conductivity enhancer.
[0009] Preferably, the raw materials by weight include: 89.5% of sodium acetate trihydrate, 1.2% of xanthan gum, 5.5% of nucleating agent, and 3.8% of heat conductive agent.
[0010] Preferably, the raw materials by weight include: 88% of sodium acetate trihydrate, 1.5% of xanthan gum, 6% of nucleating agent, and 4.5% of heat conductive agent.
[0011] Preferably, the raw materials by weight include: 92.5% of sodium acetate trihydrate, 0.5% of xanthan gum, 4% of nucleating agent, and 3% of heat conductive agent.
[0012] Preferably, the raw materials by weight include: 90% of sodium acetate trihydrate, 1% of xanthan gum, 5% of nucleating agent, and 4% of heat conductive agent.
[0013] Preferably, the nucleating agent is disodium hydrogen phosphate dodecahydrate.
[0014] Preferably, the heat conductive agent is expanded graphite.
[0015] The present invention also provides a preparation process for a medium-temperature phase change heat storage material, specifically including the following steps:
[0016] S1. Gradient mixing by a three-dimensional mixer: Dry mixing is achieved by using a three-dimensional mixer. Through the combined action of multi-directional throwing, convective shearing, and diffusion movement, the nano-scale phase change material and auxiliary materials of other particle sizes are fully dispersed and mixed, and the mixing uniformity can reach over 98%. This process fundamentally solves the drawbacks of traditional melting processes, such as full-process heat preservation, difficult canning, and high energy consumption.
[0017] S2. Dynamic compression molding: Based on a servo closed-loop control pressure molding device of a hydraulic system, combined with automatic weighing feedback control for compression molding, the density of the phase change material is controlled at 1.8 - 2.2 g / cm 3 , solving the problem of difficult canning in traditional processes;
[0018] S3. High-density polyethylene plus polypropylene canning and aluminum foil heat sealing: Using an HDPE or PP co-extrusion blow molding container and aluminum foil hot melt sealing technology, under the combined double encapsulation, the sealing performance and durability are enhanced, preventing material leakage and air oxidation;
[0019] S4. Ultrasonic cavitation treatment: In the latter stage of the process, 40 kHz high-frequency ultrasonic waves are introduced to trigger the cavitation effect under the condition of maintaining the phase change temperature, inducing the phase change material to transform from a metastable structure to a homogeneous state, ultimately achieving the purpose of increasing the phase change latent heat, reducing the supercooling degree, and reducing the risk of phase separation.
[0020] Preferably, the wall thickness of the blow molding container in step S3 is 1.2 ± 0.05 mm.
[0021] Preferably, the power density of the high-frequency ultrasonic wave in the step S4 is 2.5W / cm 2 .
[0022] (III) Beneficial effects
[0023] The present invention provides a medium-temperature phase change heat storage material formula and a preparation process. Compared with the prior art, the following beneficial effects are achieved:
[0024] (1) For the medium-temperature phase change heat storage material formula and the preparation process, sodium acetate trihydrate is used as the main phase change material, and there is a significant supercooling phenomenon. By adding disodium hydrogen phosphate dodecahydrate as a nucleating agent to reduce the supercooling degree, during the heat storage process, since the phase change temperature of disodium hydrogen phosphate dodecahydrate is lower than that of sodium acetate trihydrate, sodium acetate trihydrate will seize its free water when the phase change of disodium hydrogen phosphate dodecahydrate is completed to make it anhydrous disodium hydrogen phosphate. These anhydrous disodium hydrogen phosphates can be used as crystal nuclei to promote the crystallization and heat release of sodium acetate trihydrate in the ideal temperature range when sodium acetate trihydrate releases heat. The optimization of this material component can significantly reduce the supercooling degree to within 5°C, and improve the controllability and stability of the phase change process.
[0025] (2) For the medium-temperature phase change heat storage material formula and the preparation process, xanthan gum is used as a thickening agent. By forming a three-dimensional network structure, the phase change material solution is effectively fixed, avoiding the problem of solid-liquid stratification caused by density differences during the phase change process, and prolonging the cycle life of the material.
[0026] (3) For the medium-temperature phase change heat storage material formula and the preparation process, expanded graphite makes up for the low thermal conductivity defect of the phase change material with a high thermal conductivity network structure, so that the effective thermal conductivity of the composite material is increased to 3 - 5W / m·K, significantly accelerating the heat storage / release rate. At the same time, the nano-porous structure and high specific surface area of expanded graphite will form a capillary effect and porous adsorption, which can inhibit the macroscopic fluidity of the phase change material solution and also play a role in inhibiting phase separation. Description of the drawings
[0027] Figure 1 is a flow chart of the preparation process of the present invention. Detailed implementation manners
[0028] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.
[0029] Please refer to Figure 1 , the embodiments of the present invention provide four technical solutions: a medium-temperature phase change heat storage material formula and a preparation process, which specifically include the following embodiments:
[0030] Example 1: A formulation of a medium-temperature phase change heat storage material, the raw materials of which by weight include: 89.5% of sodium acetate trihydrate, 1.2% of xanthan gum, 5.5% of nucleating agent, and 3.8% of heat conductive agent. The nucleating agent is disodium hydrogen phosphate dodecahydrate, and the heat conductive agent is expanded graphite.
[0031] The embodiment of the present invention also provides a preparation process of a medium-temperature phase change heat storage material, which specifically includes the following steps:
[0032] S1. Gradient mixing by a three-dimensional mixer: Use a three-dimensional mixer to achieve dry mixing. Through the combined action of multi-directional sprinkling, convective shearing, and diffusion movement, the nano-level phase change material and auxiliary materials of other particle sizes are fully dispersed and mixed, and the mixing uniformity can reach more than 98%. This process fundamentally solves the disadvantages of the traditional melting process, such as full-course heat preservation, difficult canning, and high energy consumption.
[0033] S2. Dynamic compression molding: Based on a servo closed-loop control pressure forming device of a hydraulic system, combined with automatic weighing feedback control for compression molding, the density of the phase change material is controlled at 1.8 - 2.2 g / cm 3 , solving the problem of difficult canning in the traditional process;
[0034] S3. Canning with high-density polyethylene plus polypropylene and heat-sealing with aluminum foil: Use an HDPE or PP co-extrusion blow molding container and aluminum foil hot melt sealing technology. Under the combined double encapsulation, the sealing performance and durability are enhanced, preventing material leakage and air oxidation. The wall thickness of the blow molding container is 1.2 ± 0.05 mm;
[0035] S4. Ultrasonic cavitation treatment: Introduce 40 kHz high-frequency ultrasonic waves in the latter stage of the process to trigger the cavitation effect under the condition of maintaining the phase change temperature above, inducing the phase change material to transform from a metastable structure to a homogeneous state, ultimately achieving the purpose of increasing the phase change latent heat, reducing the supercooling degree, and reducing the risk of phase separation. The power density of the high-frequency ultrasonic wave is 2.5 W / cm 2 .
[0036] Example 2: A formulation of a medium-temperature phase change heat storage material, the raw materials of which by weight include: 88% of sodium acetate trihydrate, 1.5% of xanthan gum, 6% of nucleating agent, and 4.5% of heat conductive agent. The nucleating agent is disodium hydrogen phosphate dodecahydrate, and the heat conductive agent is expanded graphite.
[0037] The embodiment of the present invention also provides a preparation process of a medium-temperature phase change heat storage material, which specifically includes the following steps:
[0038] S1. Gradient mixing by three-dimensional mixer: The dry mixing is achieved by a three-dimensional mixer. Through the combined action of multi-directional spraying, convective shearing, and diffusion movement, the nano-phase change material and auxiliary materials of other particle sizes are fully dispersed and mixed, and the mixing uniformity can reach over 98%. This process fundamentally solves the disadvantages of traditional melting processes, such as full-course heat preservation, difficult canning, and high energy consumption.
[0039] S2. Dynamic compression molding: Based on a servo closed-loop control pressure molding device of a hydraulic system, combined with automatic weighing feedback control for compression molding, the density of the phase change material is controlled at 1.8 - 2.2 g / cm 3 , solving the problem of difficult canning in traditional processes.
[0040] S3. Canning with high-density polyethylene plus polypropylene and heat-sealing with aluminum foil: Using an HDPE or PP co-extruded blow-molded container and aluminum foil hot-melt sealing technology, under the combined double packaging, the sealing performance and durability are enhanced, preventing material leakage and air oxidation. The wall thickness of the blow-molded container is 1.2 ± 0.05 mm.
[0041] S4. Ultrasonic cavitation treatment: In the latter stage of the process, 40 kHz high-frequency ultrasonic waves are introduced to trigger the cavitation effect under the condition of maintaining the phase change temperature above, inducing the phase change material to transform from a metastable structure to a homogeneous state, ultimately achieving the purpose of increasing the phase change latent heat, reducing the supercooling degree, and lowering the risk of phase separation. The power density of the high-frequency ultrasonic waves is 2.5 W / cm 2 .
[0042] Example 3: A formula for a medium-temperature phase change heat storage material, the raw materials of which include, by weight: 92.5% of sodium acetate trihydrate, 0.5% of xanthan gum, 4% of nucleating agent, and 3% of heat-conducting agent. The nucleating agent is disodium hydrogen phosphate dodecahydrate, and the heat-conducting agent is expanded graphite.
[0043] The embodiment of the present invention also provides a preparation process for a medium-temperature phase change heat storage material, which specifically includes the following steps:
[0044] S1. Gradient mixing by three-dimensional mixer: The dry mixing is achieved by a three-dimensional mixer. Through the combined action of multi-directional spraying, convective shearing, and diffusion movement, the nano-phase change material and auxiliary materials of other particle sizes are fully dispersed and mixed, and the mixing uniformity can reach over 98%. This process fundamentally solves the disadvantages of traditional melting processes, such as full-course heat preservation, difficult canning, and high energy consumption.
[0045] S2. Dynamic compression molding: Based on a servo closed-loop control pressure molding device of a hydraulic system, combined with automatic weighing feedback control for compression molding, the density of the phase change material is controlled at 1.8 - 2.2 g / cm 3 , solving the problem of difficult canning in traditional processes.
[0046] S3. High-density polyethylene plus polypropylene canning and aluminum foil heat sealing: Using HDPE or PP co-extruded blow molding containers in combination with aluminum foil hot melt sealing technology, under the dual combination packaging, the sealing performance and durability are enhanced to prevent material leakage and air oxidation. The wall thickness of the blow molding container is 1.2 ± 0.05 mm;
[0047] S4. Ultrasonic cavitation treatment: In the latter stage of the process, 40 kHz high-frequency ultrasonic waves are introduced to trigger the cavitation effect under the condition of maintaining the phase change temperature, inducing the phase change material to transform from a metastable structure to a homogeneous state, ultimately achieving the purpose of increasing the latent heat of phase change, reducing the supercooling degree, and reducing the risk of phase separation. The power density of the high-frequency ultrasonic waves is 2.5 W / cm 2 .
[0048] Example 4: A formula for medium-temperature phase change heat storage material, the raw materials of which include, by weight: 90% of sodium acetate trihydrate, 1% of xanthan gum, 5% of nucleating agent, and 4% of heat conducting agent. The nucleating agent is disodium hydrogen phosphate dodecahydrate, and the heat conducting agent is expanded graphite.
[0049] The embodiment of the present invention also provides a preparation process for the medium-temperature phase change heat storage material, which specifically includes the following steps:
[0050] S1. Three-dimensional mixer gradient mixing: Using a three-dimensional mixer to achieve dry mixing. Through the combined action of multi-directional sprinkling, convective shearing, and diffusion movement, the nano-scale phase change material and auxiliary materials of other particle sizes are fully dispersed and mixed, and the mixing uniformity can reach more than 98%. This process fundamentally solves the disadvantages of the traditional melting process, such as full-process heat preservation, difficult canning, and high energy consumption;
[0051] S2. Dynamic compression molding: Based on a servo closed-loop control pressure molding device of a hydraulic system, combined with automatic weighing feedback control for compression molding, the density of the phase change material is controlled at 1.8 - 2.2 g / cm 3 , solving the problem of difficult canning in the traditional process;
[0052] S3. High-density polyethylene plus polypropylene canning and aluminum foil heat sealing: Using HDPE or PP co-extruded blow molding containers in combination with aluminum foil hot melt sealing technology, under the dual combination packaging, the sealing performance and durability are enhanced to prevent material leakage and air oxidation. The wall thickness of the blow molding container is 1.2 ± 0.05 mm;
[0053] S4. Ultrasonic cavitation treatment: In the latter stage of the process, 40 kHz high-frequency ultrasonic waves are introduced to trigger the cavitation effect under the condition of maintaining the phase change temperature, inducing the phase change material to transform from a metastable structure to a homogeneous state, ultimately achieving the purpose of increasing the latent heat of phase change, reducing the supercooling degree, and reducing the risk of phase separation. The power density of the high-frequency ultrasonic waves is 2.5 W / cm 2 .
[0054] Purpose of Component Matching and Optimization Principle:
[0055] Supercooling Suppression: Sodium acetate trihydrate (phase change temperature is about 58 °C) is used as the main phase change material (mass ratio 88.5%), and there is a significant supercooling phenomenon (usually requires a supercooling degree of 20 °C - 30 °C to crystallize). By adding disodium hydrogen phosphate dodecahydrate as a nucleating agent (mass ratio 5.5%), the supercooling degree is reduced. During the heat storage process, since the phase change temperature of disodium hydrogen phosphate dodecahydrate is lower than that of sodium acetate trihydrate, sodium acetate trihydrate will seize its free water when the phase change of disodium hydrogen phosphate dodecahydrate is completed to make it anhydrous disodium hydrogen phosphate. These anhydrous disodium hydrogen phosphate can act as crystal nuclei during the heat release of sodium acetate trihydrate to promote the crystallization and heat release of sodium acetate trihydrate in the ideal temperature range. This optimization of the material components can significantly reduce the supercooling degree to within 5 °C, improving the controllability and stability of the phase change process.
[0056] Phase Separation Suppression: Xanthan gum (mass ratio 1.2%) is used as a thickening agent. By forming a three-dimensional network structure, it effectively fixes the phase change material solution, avoiding the problem of solid-liquid stratification caused by density differences during the phase change process and extending the cycle life of the material.
[0057] Enhanced Thermal Conductivity: Expanded graphite (3.8%) makes up for the low thermal conductivity defect of the phase change material (the thermal conductivity of sodium acetate trihydrate is about 0.5 W / m·K) with a high thermal conductivity network structure (thermal conductivity > 20 W / m·K), increasing the effective thermal conductivity of the composite material to 3 - 5 W / m·K and significantly accelerating the heat storage / release rate. At the same time, the nanoporous structure and high specific surface area of expanded graphite will form a capillary effect and porous adsorption, which can inhibit the macroscopic fluidity of the phase change material solution and also play a role in suppressing phase separation.
[0058] Meanwhile, the content not described in detail in this specification belongs to the prior art well-known to those skilled in the art.
[0059] It should be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variant thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not expressly listed, or also includes elements inherent to such process, method, article or device.
[0060] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principle and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.
Claims
1. A medium-temperature phase change heat storage material formula, characterized in that: The raw materials include, by weight: 87%-93% sodium acetate trihydrate, 0.5%-1.5% xanthan gum, 4%-6% nucleating agent and 3%-4.5% thermal conductive agent.
2. A medium-temperature phase change heat storage material formulation according to claim 1, characterized in that: The raw materials include, by weight: 89.5% sodium acetate trihydrate, 1.2% xanthan gum, 5.5% nucleating agent and 3.8% thermal conductive agent.
3. A medium-temperature phase change heat storage material formulation according to claim 1, characterized in that: The raw materials include, by weight: 88% sodium acetate trihydrate, 1.5% xanthan gum, 6% nucleating agent and 4.5% thermal conductive agent.
4. The medium-temperature phase change heat storage material formulation according to claim 1, characterized in that: The raw materials include, by weight: 92.5% sodium acetate trihydrate, 0.5% xanthan gum, 4% nucleating agent and 3% thermal conductive agent.
5. The medium-temperature phase change heat storage material formulation according to claim 1, characterized in that: The raw materials include, by weight: 90% sodium acetate trihydrate, 1% xanthan gum, 5% nucleating agent and 4% thermal conductive agent.
6. A medium-temperature phase change heat storage material formulation according to any one of claims 1 to 5, characterized in that: The nucleating agent is disodium hydrogen phosphate dodecahydrate.
7. A medium-temperature phase change heat storage material formulation according to any one of claims 1 to 5, characterized in that: The thermal conductor is expanded graphite.
8. A process for preparing the medium-temperature phase change thermal storage material according to any one of claims 1 to 5, characterized in that: The specific steps include: S1. Gradient mixing by three-dimensional mixer: A three-dimensional mixer is used to achieve dry mixing. Through the combined effects of multi-directional throwing, convection shearing and diffusion movement, the nano-scale phase change material and auxiliary materials of other particle sizes are fully dispersed and mixed; S2. Dynamic pressing: Based on the servo closed-loop control pressure forming equipment of the hydraulic system, combined with automatic weighing feedback control pressing forming, the density of the phase change material can be controlled at 1.8-2.2g / cm 3 ; S3, High-density polyethylene plus polypropylene canning and aluminum foil heat sealing: HDPE or PP co-extrusion blow molding containers are used with aluminum foil hot melt sealing technology. Under the double combination packaging, the sealing and durability are enhanced to prevent material leakage and air oxidation; S4. Ultrasonic cavitation treatment: In the latter stage of the process, 40kHz high-frequency ultrasonic waves are introduced to trigger the cavitation effect while maintaining the temperature above the phase change temperature, inducing the phase change material to transform from a metastable structure to a homogenized structure, ultimately achieving the purpose of increasing the latent heat of phase change, reducing supercooling and reducing the risk of phase separation.
9. The process for preparing a medium-temperature phase change thermal storage material according to claim 8, characterized in that: The wall thickness of the blow-molded container in step S3 is 1.2±0.05 mm.
10. The process for preparing a medium-temperature phase change thermal storage material according to claim 8, characterized in that: The power density of the high-frequency ultrasound in step S4 is 2.5 W / cm 2 .