Inorganic phase change gel state energy storage material with high phase change precision
By introducing sodium polypropionate/polyN-isopropyl acrylamide composite into inorganic phase change materials, a three-dimensional network structure is formed, which improves the phase change accuracy and stability of inorganic phase change materials, and solves the application of inorganic materials in medium and high temperatures The accuracy and environmental problems in the process have achieved efficient and low-cost energy storage materials.
Patent Information
- Application Number
- CN202411199933.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-08-29
- Publication Date
- 2025-01-10
AI Technical Summary
The inorganic phase change materials have low phase change accuracy, large supercooling degree, poor stability, high cost and difficult recycling and processing, resulting in limited in medium and high temperature applications, affecting environmental and economic benefits.
Use polysodium propionate/polyN-isopropyl acrylamide (PNIPAM) composite material as phase change accuracy adjustment material to form a three-dimensional network structure, improve the phase change accuracy of inorganic phase change materials, inhibit salt precipitation and stratification, and reduce the phenomenon of over-the-counter. and accelerate the phase transition process by temperature-sensitive PNIPAM.
The phase change accuracy of inorganic phase change materials is achieved with a low subcooling degree, good stability, low cost, easy recycling and treatment, and non-toxic to the environment.
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Figure CN119286473A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of inorganic phase change material production, and in particular to an inorganic phase change gel-state energy storage material with high phase change accuracy. Background Art
[0002] Phase change materials mainly include inorganic phase change materials and organic phase change materials. Among them, inorganic phase change materials mainly include crystalline hydrated salts, molten salts, metals or alloys, etc.; organic phase change materials mainly include paraffin, acetic acid and other organic substances. Among the four most important technical indicators of phase change materials, the most difficult technical indicator to break through is phase change accuracy. The higher the accuracy of the phase change temperature, the higher the effective energy utilization rate in engineering applications. It is not difficult for phase change materials to undergo phase change, but it is very challenging to control high phase change accuracy (≤1°C) and have high enthalpy value and stability. This is the core of the performance of phase change materials.
[0003] At present, the phase change accuracy of organic phase change materials is relatively good, which can generally be controlled within the range of 1~2℃. For example, for a material with a phase change temperature requirement of 32℃, the actual phase change temperature is 33~34℃, and the phase change temperature accuracy is generally above 1℃. The phase change accuracy of inorganic phase change materials is even lower, generally within the range of 2~3℃.
[0004] The most effective way to obtain phase change materials with high precision and high enthalpy value is to improve the purity of raw materials and reduce the influence of impurities in raw materials on phase change temperature. However, due to the limitations of purification process in raw material industry chain, it is difficult to make substantial breakthroughs.
[0005] In addition, inorganic phase change materials also use other inorganic salts to improve the phase change accuracy, which will increase the concentration of the solution inside, causing more salt precipitation, and affecting the enthalpy and stability of the material.
[0006] At present, medium and high temperature phase change materials are mainly organic materials, because inorganic materials have low phase change precision, large supercooling, and poor stability. However, organic phase change materials are not only expensive, but also very troublesome to recycle after use, and improper handling will pollute the environment. How to improve the phase change performance of inorganic materials to meet the requirements of medium and high temperature phase change materials, reduce costs, and reduce environmental pollution has become an urgent problem to be solved. Summary of the invention
[0007] The purpose of the present invention is to provide an inorganic phase change gel energy storage material with high phase change accuracy, low supercooling, good stability, low cost, easy recycling and no toxicity to the environment.
[0008] The technical solution adopted by the present invention to solve its technical problem is: An inorganic phase change gel energy storage material with high phase change accuracy, comprising 80-90wt% of inorganic phase change material and 10-20wt% of phase change accuracy adjustment material; The phase change precision adjustment material is a sodium polypropionate / poly-N-isopropylacrylamide composite material.
[0009] The phase change accuracy of the material of the present invention is ≤1°C. In order to improve the phase change accuracy, supercooling and stability, the present invention innovatively introduces a phase change accuracy adjustment material that can effectively improve the phase change accuracy - sodium polyacrylate / poly N-isopropylacrylamide (PNIPAM) composite material in the inorganic phase change material. Sodium polyacrylate and PNIPAM are compounded to form a three-dimensional network composite structure. The sodium polyacrylate in the material has high water absorption and can absorb the inorganic phase change material into the material, solving the stability problem of the coexistence of PNIPAM and inorganic salts, while effectively inhibiting the stratification phenomenon caused by the salt precipitation of inorganic materials, improving the stability of the material, and reducing the supercooling of the material; PNIPAM in the material is particularly sensitive to temperature, and will rapidly undergo a volume phase change at 33°C and absorb heat, thereby accelerating the phase change of the inorganic phase change material and improving the phase change accuracy.
[0010] The addition of phase change precision regulating materials enables the final material to form a gel morphology that can effectively inhibit the stratification phenomenon caused by the salt precipitation of inorganic materials, improve the stability of the material, and reduce the supercooling of the material.
[0011] The inorganic phase change material is composed of 20-50wt% of inorganic salt and 50-80wt% of water.
[0012] The inorganic salt is selected from one or more of calcium chloride, sodium chloride, potassium chloride, magnesium chloride, ammonium chloride, sodium sulfate, sodium carbonate, disodium hydrogen phosphate, and potassium carbonate.
[0013] The preparation method of the phase change precision adjustment material is as follows: (1) 100 parts by weight of acrylic acid, 30-50 parts by weight of N-isopropylacrylamide, and 150-200 parts by weight of water are mixed, the temperature is raised to 50-55°C, and the mixture is stirred and mixed; (2) Maintaining the temperature, continue to add NaOH solution, stir and mix, then add N,N-methylenebisacrylamide, stir and mix, then raise the temperature to 60-65°C, slowly add potassium persulfate aqueous solution, and react for 120-180 minutes after the addition is complete to obtain a crude phase change precision adjustment material; (3) Drying, crushing and sieving the crude phase change precision adjustment material to obtain the phase change precision adjustment material. N,N-methylenebisacrylamide is a crosslinking agent and potassium persulfate is an initiator.
[0014] Preferably, the amount of potassium persulfate used is 1-2% by weight of acrylic acid.
[0015] Preferably, the mass concentration of the potassium persulfate aqueous solution is 20-25%.
[0016] Preferably, the amount of NaOH used is 15-20% by weight of acrylic acid.
[0017] Preferably, the mass concentration of the NaOH solution is 30-40%.
[0018] Preferably, the amount of N,N-methylenebisacrylamide used is 0.5-1% by weight of acrylic acid.
[0019] The beneficial effects of the present invention are as follows: the phase change accuracy of the material of the present invention is ≤1°C, the phase change accuracy is high, the supercooling degree is low, the stability is good, the cost is low, the recycling process is easy, and the material is non-toxic to the environment. BRIEF DESCRIPTION OF THE DRAWINGS
[0020] Figure 1 It is the enthalpy value and melting point test diagram of Example 1; Figure 2 It is the enthalpy value and melting point test diagram of Example 2; Figure 3 It is the enthalpy value and melting point test diagram of Example 3; Figure 4 This is the enthalpy value and melting point test diagram of comparative example 1; Figure 5 This is the enthalpy value and melting point test diagram of Comparative Example 2. DETAILED DESCRIPTION
[0021] The technical solution of the present invention is further described in detail below through specific embodiments.
[0022] In the present invention, unless otherwise specified, the raw materials and equipment used can be purchased from the market or are commonly used in the art. The methods in the following embodiments, unless otherwise specified, are all conventional methods in the art.
[0023] Embodiment 1: An inorganic phase change gel energy storage material with high phase change accuracy: 1. Preparation of Inorganic Phase Change Materials Take 5 grams of sodium chloride and 26 grams of sodium sulfate, add 69 grams of water, heat to 50°C, stir for 30 minutes and set aside.
[0024] 2. Sodium polyacrylate / poly (N-isopropylacrylamide) composite materials (1) Add 100 g of acrylic acid and 40 g of N-isopropylacrylamide to 180 g of water, heat to 50°C, and stir to mix; (2) Maintaining the temperature, continue to add 60 g of 30% NaOH solution, stir and mix, then add 0.7 g of N,N-methylenebisacrylamide, stir and mix, then raise the temperature to 60°C, slowly add 7.5 g of 20% potassium persulfate aqueous solution, drip it for 1 hour, and react for 120 minutes after the dripping is completed to obtain a yellow-brown composite crude product; (3) The crude composite material is dried at 90° C., crushed, and sieved to obtain a sodium polyacrylate / poly (N-isopropylacrylamide) composite material.
[0025] 3. Preparation of Inorganic Phase Change Gel Energy Storage Materials 15 g of sodium polyacrylate / poly (N-isopropylacrylamide) composite material was added to 85 g of the prepared inorganic phase change material, and the mixture was stirred at 25° C. for 30 min to obtain a phase change material.
[0026] Embodiment 2: An inorganic phase change gel energy storage material with high phase change accuracy: 1. Preparation of Inorganic Phase Change Materials Take 50 grams of potassium carbonate, add 50 grams of water, heat to 50°C, stir for 30 minutes and set aside.
[0027] 2. Sodium polyacrylate / poly (N-isopropylacrylamide) composite materials (1) Mix 100 g of acrylic acid and 50 g of N-isopropylacrylamide with 200 g of water, heat to 55°C, and stir to mix; (2) Maintaining the temperature, continue to add 50 g of 40% NaOH solution, stir and mix, then add 1 g of N,N-methylenebisacrylamide, stir and mix, then raise the temperature to 65°C, slowly add 8 g of 25% potassium persulfate aqueous solution dropwise, and drip it for 1 hour. After the dripping is completed, react for 180 minutes to obtain a crude composite material; (3) The crude composite material is dried at 90° C., crushed, and sieved to obtain a sodium polyacrylate / poly (N-isopropylacrylamide) composite material.
[0028] 3. Preparation of Inorganic Phase Change Gel Energy Storage Materials 10 g of sodium polyacrylate / poly (N-isopropylacrylamide) composite material was added to 90 g of the prepared inorganic phase change material, and the mixture was stirred at 25° C. for 30 min to obtain a phase change material.
[0029] Embodiment 3: An inorganic phase change gel energy storage material with high phase change accuracy: 1. Preparation of Inorganic Phase Change Materials Take 20 grams of disodium hydrogen phosphate, add 80 grams of water, heat to 40°C, stir for 30 minutes and set aside.
[0030] 2. Sodium polyacrylate / poly (N-isopropylacrylamide) composite materials (1) Add 100 g of acrylic acid and 30 g of N-isopropylacrylamide to 150 g of water, heat to 50°C, and stir to mix; (2) Maintaining the temperature, continue to add 50 g of 30% NaOH solution, stir and mix, then add 0.5 g of N,N-methylenebisacrylamide, stir and mix, then raise the temperature to 60°C, slowly add 5 g of 20% potassium persulfate aqueous solution dropwise, and drip it for 1 hour. After the dripping is completed, react for 120 minutes to obtain a crude composite material; (3) The crude composite material is dried at 90° C., crushed, and sieved to obtain a sodium polyacrylate / poly (N-isopropylacrylamide) composite material.
[0031] 3. Preparation of Inorganic Phase Change Gel Energy Storage Materials 20 grams of sodium polyacrylate / poly (N-isopropylacrylamide) composite material was added to 80 grams of prepared inorganic phase change material, and the mixture was stirred at 25° C. for 30 minutes to obtain a phase change material.
[0032] Comparative Example 1 5 g of sodium chloride and 26 g of sodium sulfate were added to 69 g of water, and the mixture was heated to 50° C. and stirred for 30 minutes to obtain an inorganic phase change material.
[0033] Comparative Example 2 An inorganic phase change energy storage material: 1. Preparation of Inorganic Phase Change Materials Take 5 grams of sodium chloride and 26 grams of sodium sulfate, add 69 grams of water, heat to 50°C, stir for 30 minutes and set aside.
[0034] 2. Preparation of Inorganic Phase Change Energy Storage Materials 15 g of poly (N-isopropylacrylamide) was added to 85 g of the prepared inorganic phase change material, and the mixture was stirred at 25° C. for 30 min.
[0035] The above-described embodiment is only a preferred solution of the present invention and does not limit the present invention in any form. There are other variations and modifications without exceeding the technical solution described in the claims.
Claims
1. An inorganic phase change gel energy storage material with high phase change accuracy, characterized in that: It is composed of 80-90wt% of inorganic phase change material and 10-20wt% of phase change precision adjustment material; The phase change precision adjustment material is a sodium polyacrylate / poly-N-isopropylacrylamide composite material.
2. The inorganic phase change gel energy storage material with high phase change accuracy according to claim 1, characterized in that: The inorganic phase change material is composed of 20-50wt% of inorganic salt and 50-80wt% of water.
3. The inorganic phase change gel energy storage material with high phase change accuracy according to claim 2, characterized in that: The inorganic salt is selected from one or more of calcium chloride, sodium chloride, potassium chloride, magnesium chloride, ammonium chloride, sodium sulfate, sodium carbonate, disodium hydrogen phosphate, and potassium carbonate.
4. The inorganic phase change gel energy storage material with high phase change accuracy according to claim 1, characterized in that: The preparation method of the phase change precision adjustment material is as follows: (1) 100 parts by weight of acrylic acid, 30-50 parts by weight of N-isopropylacrylamide, and 150-200 parts by weight of water are mixed, the temperature is raised to 50-55°C, and the mixture is stirred and mixed; (2) Maintaining the temperature, continue to add NaOH solution, stir and mix, then add N,N-methylenebisacrylamide, stir and mix, then raise the temperature to 60-65°C, slowly add potassium persulfate aqueous solution, and react for 120-180 minutes after the addition is complete to obtain a crude phase change precision adjustment material; (3) Drying, crushing and sieving the crude phase change precision adjustment material to obtain the phase change precision adjustment material.
5. The inorganic phase change gel energy storage material with high phase change accuracy according to claim 4, characterized in that: The dosage of potassium persulfate is 1-2% of the weight of acrylic acid.
6. The inorganic phase change gel energy storage material with high phase change accuracy according to claim 5, characterized in that: The mass concentration of the potassium persulfate aqueous solution is 20-25%.
7. The inorganic phase change gel energy storage material with high phase change accuracy according to claim 4, characterized in that: The amount of NaOH used is 15-20% by weight of acrylic acid.
8. The inorganic phase change gel energy storage material with high phase change accuracy according to claim 7, characterized in that: The mass concentration of NaOH solution is 30-40%.
9. The inorganic phase change gel energy storage material with high phase change accuracy according to claim 4, characterized in that: The amount of N,N-methylenebisacrylamide used is 0.5-1% of the weight of acrylic acid.