Phase change energy storage ink, preparation method and application thereof

Abstract

The present application relates to the technical field of phase change energy storage ink, solves the technical problems that the current phase change energy storage coupling solar interface evaporation structure has the difficulty in accurate structure manufacturing and the phase change material is easy to leak in the evaporation process, especially relates to a kind of phase change energy storage ink, preparation method and application thereof, comprising: under stirring condition, phase change energy storage material, sodium alginate, emulsifier, carbon nanotube, polyethylene glycol, water are uniformly mixed according to ratio, and mixture A is obtained;After sealing and heat preservation of mixture A, mixture B is obtained by constant temperature stirring;Mixture B is naturally cooled to room temperature, and phase change energy storage ink for 3D printing is obtained.The phase change energy storage ink provided by the present application has higher heat storage density, the phase change temperature is located at 4 DEG C-280 DEG C, and has better printing performance at the same time, can be applied to the phase change energy storage coupling utilization of solar energy and the field of phase change heat and mass transfer, and can be directly used for 3D printing forming of solar interface evaporation structure.

Description

Technical Field

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

[0002] Evaporation is a ubiquitous phase change and heat transfer phenomenon in nature, playing a vital role in energy production, environmental protection, food processing, and chemical production. Solar evaporators are key carriers for zero-carbon emission seawater desalination and wastewater purification using solar energy. Compared to traditional bulk heating methods, solar interfacial evaporation technology confines the phase change heat and mass transfer process to the water-air interface through photothermal conversion materials, achieving localized heat concentration at the gas-liquid phase change interface. This effectively reduces heat loss in the bulk water phase, significantly improving evaporation efficiency and rate. Currently, solar evaporators often use polymers, semiconductors, metals, and carbon-based materials as the photothermal conversion layer, combined with porous support structures to construct water transport channels, thereby enhancing light absorption and evaporation rates.

[0003] The aforementioned evaporation systems generally rely on real-time photothermal drive, and their heat source is significantly intermittent. When solar irradiance weakens or at night, the evaporation interface temperature drops rapidly, and the evaporation rate decreases significantly, making continuous and stable operation difficult. Furthermore, in environments with fluctuating light levels, such as day-night and cloudy / sunny conditions, frequent changes in interface temperature also affect evaporation efficiency and structural stability. Phase change energy storage materials can absorb or release a large amount of latent heat through a phase change process, thereby achieving the storage and regulation of environmental thermal energy with fluctuating characteristics. Therefore, by setting phase change energy storage units below or inside the evaporation layer, and introducing phase change energy storage materials into the solar evaporator, photothermal energy and environmental thermal energy can be stored when there is sufficient sunlight or the ambient temperature is high, and the internally stored thermal energy can be released when sunlight weakens or the ambient temperature decreases. This enhances evaporation performance under conditions of no sunlight or low ambient temperature, and improves the utilization efficiency of solar interface evaporators or phase change energy storage systems for all-weather solar and environmental thermal energy.

[0004] Currently, most phase change materials used for thermal energy storage are high-purity paraffin-based organic phase change materials, with a latent heat of fusion generally ranging from 200 to 240 J / g, exhibiting high heat storage density and good chemical stability. To improve their structural stability, some studies have also employed inorganic particles and polymer materials to encapsulate or microencapsulate paraffin to suppress melt leakage. Besides organic phase change materials, liquid metals and low-melting-point alloys have also been proposed in recent years as novel phase change energy storage materials to improve thermal conductivity and thermal storage efficiency. Low-melting-point metal materials and alloys, due to their high thermal conductivity, high volumetric latent heat, and wide phase change temperature range, can overcome the shortcomings of traditional organic phase change materials, such as low thermal conductivity, making them potential high-performance thermal energy storage media. However, the current application of phase change energy storage materials in solar evaporators usually relies on methods such as melt blending, impregnation filling, or encapsulation and curing to introduce them into the evaporation structure. The preparation process is relatively complex and requires high temperature and process control. At the same time, the distribution of existing phase change energy storage materials in the evaporation structure is difficult to control precisely, making it difficult to achieve fine coupling and integrated construction of the evaporation layer and the energy storage layer. In addition, phase change materials have strong fluidity in the molten state, and long-term thermal cycling can lead to local migration or structural deformation, which limits their application in solar evaporators. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a phase change energy storage ink, its preparation method, and its application, solving the technical problems of difficulty in precisely manufacturing the solar interface evaporation structure coupled with current phase change energy storage and the easy leakage of phase change materials during the evaporation process.

[0006] To address the aforementioned technical problems, this invention provides a method for preparing phase change energy storage ink, comprising the following steps:

[0007] S1. Under stirring conditions, phase change energy storage material, sodium alginate, emulsifier, carbon nanotubes, polyethylene glycol and water are mixed uniformly according to the ratio to obtain mixture A;

[0008] S2. After sealing and keeping the mixture A at a constant temperature, stir it to obtain mixture B.

[0009] S3. Allow mixture B to cool naturally to room temperature to obtain phase change energy storage ink for 3D printing.

[0010] Furthermore, the mass ratio of the phase change energy storage material, emulsifier, carbon nanotubes, polyethylene glycol, water, and sodium alginate is between 12:10:1:20:120:15 and 12:10:1:20:120:25.

[0011] Furthermore, the phase change energy storage material includes a single component or a mixture of multiple components such as paraffin, liquid metal, and low-melting-point alloy.

[0012] Furthermore, the melting point of the liquid metal is between 4°C and 30°C; the melting point of the low-melting-point alloy is between 30°C and 280°C.

[0013] Furthermore, the emulsifier is gum arabic powder.

[0014] Furthermore, the molecular weight of the polyethylene glycol includes 400 to 2000.

[0015] Furthermore, the temperature of the sealing and insulation is controlled at 60℃~90℃, and the insulation time is controlled at 5min~125min.

[0016] Furthermore, the temperature of the constant-temperature stirring is controlled at 60℃~90℃, and the stirring time is controlled at 15min~145min.

[0017] This invention also provides a phase change energy storage ink, prepared using the aforementioned method. Based on the prepared phase change energy storage ink, a solar energy interface evaporation structure is fabricated using 3D printing, achieving integrated construction of the evaporation structure and the energy storage structure. Furthermore, it also includes applications in the coupling utilization of solar energy in phase change energy storage and in the fields of phase change heat and mass transfer.

[0018] By employing the above technical solution, the present invention provides a phase change energy storage ink, a preparation method thereof, and its application, which has at least the following beneficial effects:

[0019] 1. The phase change energy storage ink provided by this invention has a high heat storage density and a phase change temperature ranging from 4℃ to 280℃. It also has good printing performance and can be applied to the field of phase change energy storage coupling utilization and phase change heat and mass transfer of solar energy. It can be directly used for 3D printing of solar interface evaporation structures.

[0020] 2. The phase change energy storage ink provided by this invention has good shear thinning characteristics and can be directly used for 3D printing to realize the integrated construction of evaporation structure and energy storage structure, thereby improving the controllability of structural design.

[0021] 3. This invention enhances the compatibility between phase change energy storage materials and sodium alginate by using gum arabic powder, effectively inhibiting the migration and leakage of paraffin in the molten state, and improving the structural stability and operational reliability of the material during repeated thermal cycling.

[0022] 4. While maintaining a high content of phase change energy storage material and a high heat storage density, the present invention achieves stable ink molding and enhances the continuous operation capability of the solar evaporation device under intermittent light or ambient temperature fluctuations. Attached Figure Description

[0023] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings:

[0024] Figure 1 This is a differential calorimetry (DSC) graph from Embodiment 1 of the present invention;

[0025] Figure 2 This is a differential calorimetry (DSC) graph from Embodiment 2 of the present invention;

[0026] Figure 3 This is a printing effect diagram of Embodiment 1 of the present invention;

[0027] Figure 4 This is a printing effect diagram of Embodiment 2 of the present invention;

[0028] Figure 5 This is a comparison diagram of shear thinning in Embodiment 1, Embodiment 2, and the control example of the present invention;

[0029] Figure 6 This is a comparison chart of the modulus of Embodiment 1, Embodiment 2, and the control example of the present invention. Detailed Implementation

[0030] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. This will allow for a full understanding of how the present application uses technical means to solve technical problems and achieve technical effects, and to facilitate its implementation.

[0031] Example 1:

[0032] A phase change energy storage ink suitable for 3D printing is obtained by uniformly mixing silica-coated paraffin, emulsifier, carbon nanotubes, polyethylene glycol, water, and sodium alginate in a mass fraction ratio of 12:10:1:20:120:25. The mixture is sealed and kept at 80°C for 15 minutes, and then stirred at a constant temperature of 85°C for 35 minutes. After natural cooling to room temperature and solidification, a phase change energy storage ink suitable for 3D printing is obtained.

[0033] Example 2:

[0034] Paraffin wax, emulsifier, carbon nanotubes, polyethylene glycol, water, and sodium alginate were mixed evenly in a mass fraction ratio of 12:10:1:20:120:17. The mixture was then sealed and kept at 80°C for 15 minutes, and stirred at a constant temperature of 85°C for 35 minutes. After naturally cooling to room temperature and solidification, a phase change energy storage ink suitable for 3D printing was obtained.

[0035] Example 3:

[0036] A phase change energy storage ink suitable for 3D printing is obtained by uniformly mixing Ga-In alloy, emulsifier, carbon nanotubes, polyethylene glycol, water, and sodium alginate in a mass fraction ratio of 12:10:1:20:120:15. The mixture is sealed and kept at 85°C for 20 minutes, and then stirred at a constant temperature of 85°C for 40 minutes. After natural cooling to room temperature and solidification, a phase change energy storage ink suitable for 3D printing is obtained.

[0037] Example 4:

[0038] A phase change energy storage ink suitable for 3D printing is obtained by uniformly mixing Ga metal, emulsifier, carbon nanotubes, polyethylene glycol, water, and sodium alginate in a mass fraction ratio of 12:10:1:20:120:25. The mixture is sealed and kept at 90°C for 25 minutes, and then stirred at a constant temperature of 85°C for 45 minutes. After natural cooling to room temperature and solidification, a phase change energy storage ink suitable for 3D printing is obtained.

[0039] Example for comparison:

[0040] Emulsifier, carbon nanotubes, polyethylene glycol, water, and sodium alginate were mixed uniformly in a mass ratio of 10:1:20:120:17. The mixture was then sealed and kept at 80°C for 15 minutes. The mixture was stirred at a constant temperature of 85°C for 35 minutes. After naturally cooling to room temperature and solidifying, a reference ink suitable for 3D printing was obtained.

[0041] The printing instruments used in Examples 1 and 2 were Bio-Architect printers manufactured by Hangzhou Genofi Co., Ltd., with a printing speed of 20 mm / s, a printing air pressure of 0.3 MPa, and an ink printing temperature of room temperature.

[0042] The latent heat of phase change and phase change temperature of the phase change energy storage inks prepared in Examples 1 and 2 were measured using a Netzsch DSC214 differential scanning calorimeter (DSC) from Germany. 10 mg of sample was placed in a pure aluminum sealed dish, and nitrogen was used as the test gas atmosphere. The test temperature range was 20–70 °C. Under the nitrogen atmosphere, the initial equilibrium temperature was 20 °C, and the temperature was increased to 70 °C at a rate of 5 °C / min, held at 70 °C for 3 min, and then decreased to 20 °C at a rate of 5 °C / min. The measurement results are as follows: Figure 1 and Figure 2 As shown, the thermophysical data of Examples 1-2 are shown in Table 1.

[0043] Table 1. Thermal property data of Examples 1-2 Example 1 82.98 64.51 33 20.3 12.7 Example 2 48.65 30.37 30.6 20.8 9.8

[0044] As can be seen from Table 1, both Example 1 and Example 2 possess phase change energy storage capabilities, and their melting and solidification temperatures are highly suitable for solar energy utilization and phase change heat and mass transfer applications. Figure 3 and Figure 4 As can be seen, it has good printing performance, capable of printing structures with controllable gaps on a flat surface, and also has good printing performance for three-dimensional structures, with good shape retention performance.

[0045] The shear thinning and modulus of the phase change energy storage inks prepared in Examples 1 and 2 were measured. The rheological properties of the samples were tested using a Haake Mars 60 rotational rheometer (Germany). A parallel plate clamp with a plate diameter of 25 mm and a test gap of 1 mm was used, and the test temperature was 25 °C. An appropriate amount of sample was placed between the upper and lower plates, excess sample was removed, and the sample was allowed to stand for 3 minutes to reach a stable state. The steady-state shear mode was used for testing, with shear rates set from 0.01 to 1000 s⁻¹. -1 The measurement results are as follows Figure 5 As shown. The test was conducted using a parallel plate fixture at 25℃. A suitable amount of sample was placed between the upper and lower plates, excess sample was removed, and the sample was allowed to stabilize. An oscillating stress scan (or oscillating strain scan) mode was used, with the test frequency set to 1Hz (angular frequency ω=6.283rad / s). The storage modulus (G') and loss modulus (G'') were recorded as curves of stress variation. The measurement results are shown below. Figure 6 As shown.

[0046] from Figure 5 and Figure 6 It can be seen that Examples 1, 2, and the comparative example all possess printability. Figure 5 The sodium alginate-based phase change energy storage ink demonstrates excellent shear thinning properties, ensuring smooth material extrusion during the printing process. Figure 6 The results show that the storage modulus (G') and loss modulus (G'') of the sodium alginate-based phase change energy storage ink gradually change with increasing oscillating stress in each embodiment. In the low stress range, all samples exhibit G' greater than G'', indicating that the system primarily exhibits elastic behavior and possesses a stable three-dimensional network structure. As stress further increases, G' gradually decreases, and when G' intersects with G'', it indicates that the internal network structure of the material begins to break down. Among these, Example 1 shows the highest maximum stress corresponding to G' greater than G'', indicating that Example 1 has a wider linear viscoelastic region and a stronger ability to maintain network structure stability under external shear stress, exhibiting better resistance to shear failure. In summary, Example 1 demonstrates superior overall performance and can be considered a preferred embodiment of the present invention.

[0047] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. Since the above embodiments are substantially similar to the method embodiments, their descriptions are relatively simple; relevant parts can be referred to the descriptions of the method embodiments.

[0048] The above embodiments provide a detailed description of the present invention. Specific examples have been used to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A method for preparing a phase change energy storage ink, characterized in that, The method includes the following steps: S1. Under stirring conditions, phase change energy storage material, sodium alginate, emulsifier, carbon nanotubes, polyethylene glycol and water are mixed uniformly according to the ratio to obtain mixture A; S2. After sealing and keeping the mixture A at a constant temperature, stir it to obtain mixture B. S3. Allow mixture B to cool naturally to room temperature to obtain phase change energy storage ink for 3D printing.

2. The method for preparing phase change energy storage ink according to claim 1, characterized in that, The mass ratio of the phase change energy storage material, emulsifier, carbon nanotubes, polyethylene glycol, water, and sodium alginate is between 12:10:1:20:120:15 and 12:10:1:20:120:

25.

3. The method for preparing phase change energy storage ink according to claim 1, characterized in that, The phase change energy storage material includes a single component or a mixture of multiple components such as paraffin, liquid metal, and low-melting-point alloy.

4. The method for preparing phase change energy storage ink according to claim 3, characterized in that, The melting point of the liquid metal is between 4°C and 30°C; the melting point of the low-melting-point alloy is between 30°C and 280°C.

5. The method for preparing phase change energy storage ink according to claim 1, characterized in that, The emulsifier is gum arabic powder.

6. The method for preparing phase change energy storage ink according to claim 1, characterized in that, The molecular weight of the polyethylene glycol ranges from 400 to 2000.

7. The method for preparing phase change energy storage ink according to claim 1, characterized in that, The temperature for sealing and heat preservation is controlled between 60℃ and 90℃, and the heat preservation time is controlled between 5min and 125min.

8. The method for preparing phase change energy storage ink according to claim 1, characterized in that, The temperature of the constant temperature stirring is controlled between 60℃ and 90℃, and the stirring time is controlled between 15 min and 145 min.

9. A phase change energy storage ink, characterized in that, The phase change energy storage ink is prepared by any one of the preparation methods of claims 1 to 8.

10. The application of the phase change energy storage ink as described in claim 9 in 3D printing solar interface evaporation structures realizes the integrated construction of evaporation structure and energy storage structure, and also includes applications in the fields of phase change energy storage coupling utilization of solar energy and phase change heat and mass transfer.

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