Phase change energy storage-radiation refrigeration composite material for dynamic thermal management and preparation method of phase change energy storage-radiation refrigeration composite material

Abstract

The invention discloses a phase change energy storage-radiation refrigeration composite material for dynamic heat management and a preparation method thereof, and belongs to the technical field of building and human skin heat management. The method comprises the following steps: 1, fully melting liquid metal Ga; 2, doping metal particles into the liquid metal Ga; 3, preparing a Ga-based phase change energy storage material; and 4, combining the Ga-based phase change energy storage material with a radiation refrigeration film by adopting a heat-conducting double-faced adhesive tape to obtain the phase change energy storage-radiation refrigeration composite material for dynamic heat management. The phase change energy storage-radiation refrigeration composite material for dynamic heat management prepared by the invention can realize a refrigeration effect lower than room temperature when being used in buildings, and can also realize the effects of daytime heat buffering and night heat release, so that the temperature is dynamically adjusted; the thermoelectric power generation device has good thermoelectric power generation potential, can generate an output voltage greater than 100mV in a phase change stage, and also can continuously generate an output voltage of 20mV-40mV in a non-phase change stage.

Description

Technical Field

[0001] The present invention belongs to the technical field of thermal management of buildings and human skin, and in particular relates to a phase-change energy storage-radiation refrigeration composite material for dynamic thermal management and a preparation method thereof. Background Art

[0002] The frequent occurrence of extreme high temperature weather has led to an increasing demand for refrigeration. Traditional refrigeration technologies, such as air conditioning, will produce a large amount of greenhouse gases and waste heat due to excessive use of electricity and refrigerants, exacerbating the greenhouse effect and urban heat island effect. Therefore, in the face of the challenges of energy shortage and environmental pollution, it is of great significance to find an efficient, environmentally friendly and energy-saving refrigeration method. Spectrally modulated passive radiation cooling technology can emit thermal radiation to the cold universe (≈3K) through the atmospheric transparent window (8-13μm), thereby reducing the temperature of objects to below the ambient temperature. This technology has become a refrigeration strategy that has attracted much attention.

[0003] However, these static radiative coolers can only cool objects and continue to radiate cooling on cold nights or in winter, resulting in undesirable "overcooling" at low temperatures, thereby increasing heating costs, which may offset the cooling energy saved on hot days. This single function limits its application in certain scenarios. Therefore, it is very important to develop a dynamic radiative cooling technology that adapts to changing environmental conditions.

[0004] Phase change materials are a special type of material that undergoes a reversible phase change under the action of heat and can store and release a large amount of latent heat within a specified temperature range. They have the advantages of high energy density and small temperature fluctuations. The patent document with publication number CN118342857A discloses a composite material that is resistant to thermal shock and coupled with phase change heat storage and radiation refrigeration; the melting point of liquid metal Ga is 29.8°C, close to room temperature, making it easy to switch between solid and liquid phases, accompanied by rapid performance changes, and the thermal conductivity of Ga is much higher than that of organic phase change materials.

[0005] At present, the inventions combining radiative cooling with phase change energy storage materials mainly involve combining radiative cooling films with organic phase change energy storage materials. However, traditional organic phase change materials have low thermal conductivity and cannot dissipate heat in a timely manner. In addition, they cannot exhibit the function of heating at night in low temperatures. Summary of the invention

[0006] One of the purposes of the present invention is to solve the problem that the existing static radiation refrigeration materials cannot change the refrigeration performance at low temperatures, and the organic phase change heat storage materials have low thermal conductivity;

[0007] The second purpose of the present invention is to solve the problem that existing methods are unable to prepare temperature-responsive composite materials that can achieve dual-function thermal management of cooling and heating, and have dynamic thermal management capabilities of daytime heat buffering and nighttime heat release while performing radiative cooling and cooling. A phase change energy storage-radiative cooling composite material with dynamic thermal management and a preparation method thereof are provided.

[0008] The present invention prepares Ga-based phase change energy storage materials and couples them with radiation cooling materials to develop temperature-responsive composite materials, which is expected to achieve dual-function thermal management of cooling and heating, and significantly improve the functionality and application scenarios of existing materials. The present invention not only helps to deepen the understanding of the interaction mechanism between Ga-based phase change energy storage materials and radiation cooling materials, but also promotes the development of new composite materials and opens up a new direction for the combination of phase change heat storage and radiation cooling.

[0009] A dynamic thermal management phase change energy storage-radiative refrigeration composite material has good radiative refrigeration ability during the day, and the sample temperature is lower than the ambient temperature; it has good thermal buffering ability during the day, and can produce a temperature difference of 12°C with the environment when melting and maintain it for 1 hour; it has good heat release ability at night, and can release the stored latent heat when solidifying, raising the temperature to 30°C and maintaining it for 1 hour; it has good temperature difference power generation potential, and can generate an output voltage greater than 100mV in the phase change stage, and will continue to generate an output voltage of 20mV to 40mV in the non-phase change stage.

[0010] A method for preparing a phase-change energy storage-radiative refrigeration composite material for dynamic thermal management is specifically completed in the following steps:

[0011] 1. Put the liquid metal Ga into the oven for a period of time to obtain fully melted liquid metal Ga;

[0012] 2. Add fully melted liquid metal Ga and metal particles into dilute hydrochloric acid, stir for a period of time, freeze and solidify, wash with anhydrous ethanol until neutral, and dry to obtain liquid metal Ga mixed with metal particles;

[0013] 3. Encapsulating the liquid metal Ga doped with metal particles to obtain Ga-based phase change energy storage materials;

[0014] 4. Use thermal conductive double-sided tape to combine Ga-based phase change energy storage material with radiation refrigeration film to obtain a phase change energy storage-radiation refrigeration composite material with dynamic thermal management.

[0015] Principle of the present invention:

[0016] The present invention combines a radiation cooling film with a phase change energy storage material. On the basis of the high solar reflectivity of the radiation cooling material and the infrared emissivity of the atmospheric window, the high phase change latent heat of the phase change energy storage material and the temperature rise and heat release during the solidification process caused by the supercooling of the liquid metal Ga are combined to obtain a composite material that can cool during the day and heat at night.

[0017] Compared with the prior art, the present invention has the following advantages:

[0018] 1. The preparation process of the present invention is simple and the daytime cooling effect is obvious;

[0019] Second, the phase-change energy storage-radiation refrigeration composite material for dynamic thermal management prepared by the present invention has good thermal buffering capacity during the day, and can produce a temperature difference of 12°C with the environment when melting and maintain it for 1 hour; it has good heat release capacity at night, and can release the stored latent heat when solidifying, raising the temperature to 30°C and maintaining it for 1 hour;

[0020] 3. The present invention has good potential for thermoelectric power generation, and can generate an output voltage greater than 100mV in the phase change stage, and can also continuously generate an output voltage of 20mV to 40mV in the non-phase change stage;

[0021] 4. The phase-change energy storage-radiation refrigeration composite material for dynamic thermal management prepared by the present invention makes up for the shortcoming that static radiation refrigeration materials cannot be dynamically adjusted. Due to the existence of the radiation refrigeration layer, buildings and human bodies can achieve a cooling effect below room temperature; and due to the existence of the phase-change energy storage layer, buildings and human bodies can achieve the effects of heat buffering during the day and heat release at night, thereby dynamically adjusting the temperature. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a comparison diagram of the external field temperature test and the cavity environment temperature of the phase change energy storage-radiative refrigeration composite material for dynamic thermal management prepared in Example 1 and the phase change energy storage material prepared in Comparative Example 1;

[0023] Figure 2 This is a test diagram of the outdoor temperature difference power generation performance of the dynamic thermal management phase change energy storage-radiative refrigeration composite material prepared in Example 1. DETAILED DESCRIPTION

[0024] Specific implementation method one: This implementation method is a phase change energy storage-radiation refrigeration composite material with dynamic thermal management. It has good radiation refrigeration ability during the day, and the sample temperature is lower than the ambient temperature; it has good thermal buffering ability during the day, and can produce a temperature difference of 12°C with the environment when melting, and maintain it for 1 hour; it has good heat release ability at night, and can release the stored latent heat when solidifying, raising the temperature to 30°C, and maintain it for 1 hour; it has good temperature difference power generation potential, and can generate an output voltage greater than 100mV in the phase change stage, and will continue to generate an output voltage of 20mV to 40mV in the non-phase change stage.

[0025] Specific implementation method 2: This implementation method is a preparation method of a phase change energy storage-radiation refrigeration composite material for dynamic thermal management, which is specifically completed in the following steps:

[0026] 1. Put the liquid metal Ga into the oven for a period of time to obtain fully melted liquid metal Ga;

[0027] 2. Add fully melted liquid metal Ga and metal particles into dilute hydrochloric acid, stir for a period of time, freeze and solidify, wash with anhydrous ethanol until neutral, and dry to obtain liquid metal Ga mixed with metal particles;

[0028] 3. Encapsulating the liquid metal Ga doped with metal particles to obtain Ga-based phase change energy storage materials;

[0029] 4. Use thermal conductive double-sided tape to combine Ga-based phase change energy storage material with radiation refrigeration film to obtain a phase change energy storage-radiation refrigeration composite material with dynamic thermal management.

[0030] Specific implementation method 3: This implementation method is different from specific implementation method 1 or 2 in that: the temperature of the oven in step 1 is 50°C to 70°C; the time for placing the liquid metal Ga in the oven in step 1 is 1h to 2h. The other steps are the same as those in specific implementation method 1 or 2.

[0031] Specific embodiment 4: This embodiment differs from specific embodiments 1 to 3 in that: the concentration of the dilute hydrochloric acid in step 2 is 0.15 mol / L to 0.25 mol / L; the volume ratio of the total mass of the fully melted liquid metal Ga and the metal particles to the dilute hydrochloric acid in step 2 is (10 g to 15 g): 50 mL; the stirring time in step 2 is 2 min to 5 min. The other steps are the same as those in specific embodiments 1 to 3.

[0032] Specific implementation method 5: This implementation method is different from specific implementation methods 1 to 4 in that: the freezing and solidification temperature in step 2 is -15°C to -10°C, and the freezing and solidification time is 0.5h to 1h; the drying temperature in step 2 is 50°C to 70°C, and the drying time is 1h to 3h; the metal particles in step 2 are copper particles; the particle size of the copper particles is 60μm to 80μm; the mass fraction of the metal particles in the liquid metal Ga after the metal particles are added in step 2 is 1% to 10%. The other steps are the same as those in specific implementation methods 1 to 4.

[0033] Specific implementation method 6: This implementation method is different from specific implementation methods 1 to 5 in that: in step 3, a polymer film is used to encapsulate the liquid metal Ga after the metal particles are added; the polymer film is a PE film. The other steps are the same as those of specific implementation methods 1 to 5.

[0034] Specific embodiment 7: This embodiment differs from specific embodiments 1 to 6 in that the thickness of the polymer film in step 3 is 0.06 mm to 0.1 mm; the thickness of the Ga-based phase change energy storage material in step 3 is 3 mm to 5 mm. The other steps are the same as those in specific embodiments 1 to 6.

[0035] Specific implementation eight: This implementation differs from specific implementations one to seven in that: in step four, the Ga-based phase change energy storage material and the radiation cooling film are combined using a thermally conductive double-sided adhesive, and the specific method is: the Ga-based phase change energy storage material is attached to one side of the thermally conductive double-sided adhesive, and the radiation cooling film is attached to the other side of the thermally conductive double-sided adhesive. The other steps are the same as those of specific implementations one to seven.

[0036] Specific embodiment 9: This embodiment differs from specific embodiments 1 to 8 in that the radiation cooling film in step 4 is a TPU nanofiber film, which is prepared by electrospinning using a TPU solution as a raw material. The other steps are the same as those of specific embodiments 1 to 8.

[0037] Specific embodiment 10: The difference between this embodiment and specific embodiments 1 to 9 is that the preparation method of the TPU nanofiber membrane is completed in the following steps: TPU is added to N, N-dimethylformamide, and magnetically stirred at 40℃ to 50℃ for 10h to 12h to obtain a TPU solution with a mass fraction of 15% to 20%; the TPU solution with a mass fraction of 15% to 20% is added to a 5mL disposable syringe, and a NO.22 metal needle is attached, and the receiving distance is kept at 20cm under the conditions of an ambient temperature of 40℃ and a relative humidity of 25%, and the push injection speed is maintained at 2mm / min for spinning, and then vacuum dried at 70℃ for 12h to obtain a TPU nanofiber membrane; the thickness of the TPU nanofiber membrane is 0.2mm to 0.4mm. The other steps are the same as those of specific embodiments 1 to 9.

[0038] The following examples are used to verify the beneficial effects of the present invention:

[0039] Example 1: A method for preparing a phase-change energy storage-radiative refrigeration composite material for dynamic thermal management, which is specifically completed by the following steps:

[0040] 1. Put the liquid metal Ga into an oven at 60°C for 1 hour to obtain fully melted liquid metal Ga;

[0041] 2. Add the fully melted liquid metal Ga and metal particles into dilute hydrochloric acid with a concentration of 0.2 mol / L, stir for 2 minutes, and then freeze and solidify at -15°C for 0.5 hours, then wash with anhydrous ethanol until neutral, and dry in an oven at a temperature of 60°C for 1 hour to obtain liquid metal Ga doped with metal particles;

[0042] The volume ratio of the total mass of the fully melted liquid metal Ga and the metal particles to the dilute hydrochloric acid in step 2 is 12.6 g:50 mL;

[0043] The metal particles described in step 2 are copper particles; the particle size of the copper particles is 70 μm;

[0044] The mass fraction of the metal particles in the liquid metal Ga after the metal particles are doped in step 2 is 5%;

[0045] 3. Using a PE film with a thickness of 0.08 mm to encapsulate the liquid metal Ga mixed with metal particles to obtain a Ga-based phase change energy storage material;

[0046] The thickness of the Ga-based phase change energy storage material described in step 3 is 4 mm;

[0047] Fourth, a Ga-based phase change energy storage material is attached to one side of the thermally conductive double-sided adhesive, and a radiation cooling film is attached to the other side of the thermally conductive double-sided adhesive to obtain a phase change energy storage-radiation cooling composite material for dynamic thermal management;

[0048] The radiation cooling film in step 4 is a TPU nanofiber film, which is prepared by electrospinning using a TPU solution as a raw material;

[0049] The preparation method of the TPU nanofiber membrane is specifically completed according to the following steps: adding TPU (thermoplastic polyurethane) to N,N-dimethylformamide (DMF), stirring with magnetic stirring at 40°C for 12 hours to obtain a TPU solution with a mass fraction of 18%; adding the TPU solution with a mass fraction of 18% to a 5mL disposable syringe, and attaching a NO.22 metal needle, maintaining a receiving distance of 20cm under an ambient temperature of 40°C and a relative humidity of 25%, maintaining a push injection speed of 2mm / min for spinning, and then vacuum drying at 70°C for 12 hours to obtain a TPU nanofiber membrane; the thickness of the TPU nanofiber membrane is 0.3mm.

[0050] Comparative Example 1: A method for preparing a phase change energy storage material, which is specifically completed by the following steps:

[0051] 1. Put the liquid metal Ga into an oven at 60°C for 1 hour to obtain fully melted liquid metal Ga;

[0052] 2. Use a 0.08mm thick PE film to encapsulate the fully melted liquid metal Ga to obtain a phase change energy storage material.

[0053] Figure 1 It is a comparison diagram of the external field temperature test and the cavity environment temperature of the phase change energy storage-radiative refrigeration composite material for dynamic thermal management prepared in Example 1 and the phase change energy storage material prepared in Comparative Example 1;

[0054] from Figure 1 It can be seen that the phase change energy storage-radiation refrigeration composite material with dynamic thermal management prepared in Example 1 has a daytime temperature lower than the ambient temperature, while the temperature of the phase change energy storage material prepared in Comparative Example 1 is higher than the ambient temperature; and the phase change energy storage-radiation refrigeration composite material with dynamic thermal management prepared in Example 1 exhibits good dynamic thermal management performance, which can produce a temperature difference of about 12°C with the environment when melted and maintain it for about 1 hour, has good heat release ability at night, and can release stored latent heat when solidified, raising the temperature to 30°C and maintaining it for about 1 hour.

[0055] Figure 2 This is a test diagram of the outdoor temperature difference power generation performance of the dynamic thermal management phase change energy storage-radiative refrigeration composite material prepared in Example 1;

[0056] from Figure 2 It can be seen that the dynamic thermal management phase change energy storage-radiative refrigeration composite material prepared in Example 1 can produce a large temperature difference between the two ends of the thermoelectric power generation sheet in the phase change stage, and can generate an output voltage greater than 100mV; and it will also continue to generate an output voltage of 20mV to 40mV in the non-phase change stage.

Claims

1. A dynamic thermal management phase change energy storage-radiation refrigeration composite material, characterized in that The dynamic thermal management phase change energy storage-radiative cooling composite material has good radiative cooling capability during the day, and the sample temperature is lower than the ambient temperature; It has good heat buffering capacity during the day, and can produce a temperature difference of 12°C with the environment when melting, and maintain it for 1 hour; It has good heat release ability at night, and can release stored latent heat when solidifying, raising the temperature to 30°C and maintaining it for 1 hour; it has good temperature difference power generation potential, and can generate an output voltage greater than 100mV in the phase change stage, and will continue to generate an output voltage of 20mV to 40mV in the non-phase change stage.

2. A method for preparing a dynamic thermal management phase change energy storage-radiation refrigeration composite material according to claim 1, characterized in that The preparation method is specifically completed according to the following steps:

1. Put the liquid metal Ga into the oven for a period of time to obtain fully melted liquid metal Ga; 2. Add fully melted liquid metal Ga and metal particles into dilute hydrochloric acid, stir for a period of time, freeze and solidify, wash with anhydrous ethanol until neutral, and dry to obtain liquid metal Ga mixed with metal particles; 3. Encapsulating the liquid metal Ga doped with metal particles to obtain Ga-based phase change energy storage materials; 4. Use thermal conductive double-sided tape to combine Ga-based phase change energy storage material with radiation refrigeration film to obtain a phase change energy storage-radiation refrigeration composite material with dynamic thermal management.

3. The method for preparing a dynamic thermal management phase change energy storage-radiative refrigeration composite material according to claim 2, characterized in that The temperature of the oven described in step 1 is 50° C. to 70° C.; the time for placing the liquid metal Ga in the oven in step 1 is 1 h to 2 h.

4. The method for preparing a dynamic thermal management phase change energy storage-radiative refrigeration composite material according to claim 2, characterized in that The concentration of the dilute hydrochloric acid described in step 2 is 0.15 mol / L to 0.25 mol / L; the volume ratio of the total mass of the fully melted liquid metal Ga and the metal particles described in step 2 to the dilute hydrochloric acid is (10 g to 15 g): 50 mL; the stirring time described in step 2 is 2 min to 5 min.

5. The method for preparing a dynamic thermal management phase change energy storage-radiative refrigeration composite material according to claim 2, characterized in that The freezing and solidification temperature described in step 2 is -15°C to -10°C, and the freezing and solidification time is 0.5h to 1h; the drying temperature described in step 2 is 50°C to 70°C, and the drying time is 1h to 3h; the metal particles described in step 2 are copper particles; the particle size of the copper particles is 60μm to 80μm; the mass fraction of the metal particles in the liquid metal Ga after the metal particles are doped in step 2 is 1% to 10%.

6. The method for preparing a dynamic thermal management phase change energy storage-radiative refrigeration composite material according to claim 2, characterized in that In step three, a polymer film is used to encapsulate the liquid metal Ga after being doped with metal particles; the polymer film is a PE film.

7. The method for preparing a dynamic thermal management phase change energy storage-radiative refrigeration composite material according to claim 6, characterized in that The thickness of the polymer film described in step three is 0.06 mm to 0.1 mm; the thickness of the Ga-based phase change energy storage material described in step three is 3 mm to 5 mm.

8. The method for preparing a dynamic thermal management phase change energy storage-radiative refrigeration composite material according to claim 2, characterized in that In step 4, the Ga-based phase change energy storage material and the radiation cooling film are combined using a thermally conductive double-sided adhesive. The specific method is: the Ga-based phase change energy storage material is attached to one side of the thermally conductive double-sided adhesive, and the radiation cooling film is attached to the other side of the thermally conductive double-sided adhesive.

9. The method for preparing a dynamic thermal management phase change energy storage-radiative refrigeration composite material according to claim 2, characterized in that The radiation cooling film described in step 4 is a TPU nanofiber film, and the TPU nanofiber film is prepared by using a TPU solution as a raw material and an electrospinning method.

10. The method for preparing a dynamic thermal management phase change energy storage-radiative refrigeration composite material according to claim 9, characterized in that The preparation method of the TPU nanofiber membrane is specifically completed according to the following steps: adding TPU to N,N-dimethylformamide, magnetically stirring at 40°C to 50°C for 10h to 12h to obtain a TPU solution with a mass fraction of 15% to 20%; adding the TPU solution with a mass fraction of 15% to 20% to a 5mL disposable syringe, and attaching a NO.22 metal needle, keeping the receiving distance at 20cm and the injection speed at 2mm / min for spinning under the conditions of an ambient temperature of 40°C and a relative humidity of 25%, and then vacuum drying at 70°C for 12h to obtain a TPU nanofiber membrane; the thickness of the TPU nanofiber membrane is 0.2mm to 0.4mm.

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