Application method of graphene paper-cut configuration in solid-state refrigeration

Abstract

The application discloses an application method of a graphene paper-cutting configuration in solid-state refrigeration, the graphene paper-cutting configuration can be used as a refrigeration working medium in the solid-state refrigeration, and generates a thermal effect to perform solid-state refrigeration under the drive of uniaxial stress; the graphene paper-cuting configuration is obtained by cutting the graphene, and can generate a configuration capable of being flipped out of a plane after being stretched. The graphene paper-cutting configuration can generate 60 J·kg ‑1 ·K ‑1 isothermal entropy change, adiabatic temperature change of 25K. And the refrigeration interval of the material is large, and is not dependent on the phase transition point of the material, and the stretching and compression can generate temperature change in any temperature zone, which is far superior to other solid-state refrigeration material systems. Meanwhile, the thermal conductivity of the material is high, and can reach 62 W·m ‑1 ·K ‑1 Although the paper-cutting structure weakens the heat conduction of the graphene, the thermal conductivity is still far greater than that of traditional solid-state refrigeration materials.

Description

TECHNICAL FIELD

[0001] The application relates to the field of solid-state refrigeration technology, and particularly relates to an application method of a graphene paper-cut configuration in solid-state refrigeration. BACKGROUND

[0002] Solid-state refrigeration technology is widely considered as one of the most promising technologies to replace traditional gas compression refrigeration due to its many advantages, especially the refrigeration scheme based on solid-state phase change heat effect (such as magnetic caloric effect, electric caloric effect, elastic caloric effect and pressure caloric effect). By applying an external field to induce reversible thermal change of the material, high-efficiency energy conversion can be achieved. This kind of technology has the characteristics of low energy consumption, low noise, low maintenance cost and zero carbon emission, and has broad application prospects in the fields of aerospace and space exploration, electronic equipment cooling, medical and biotechnology, household appliance industry and the like. From the aspects of environmental protection, economy, feasibility and foresight, solid-state refrigeration technology has become an important research direction of the next generation of green refrigeration technology.

[0003] However, the existing solid-state refrigeration material usually needs a driving field of hundreds of megapascals or more, and the refrigeration region is limited near the phase change point. At the same time, the low thermal conductivity limits the heat transfer, making it difficult to realize large-scale application. Therefore, how to fundamentally improve the comprehensive performance of solid-state refrigeration material has become the forefront and core problem in this field. In recent years, the rapid development of two-dimensional materials has provided a new way out for this problem. Since 2004, graphene was first peeled off from graphite, and people found that two-dimensional materials can exist stably at room temperature and pressure. As a two-dimensional carbon material with excellent electrical conductivity, thermal conductivity, mechanical strength and chemical stability, graphene has shown wide application prospects in new energy, environmental protection, medical treatment, electronics and other fields due to its unique physical and chemical properties. In 2024, researchers discovered a huge elastic caloric effect on paper-cut graphene, which provided a new idea and understanding for the field of solid-state refrigeration. By applying the paper-cut configuration to thermoplastic polyurethane elastomer, the effectiveness of the paper-cut strategy was confirmed. Compared with traditional refrigeration materials relying on phase change temperature, this material can realize refrigeration application in a wide temperature range of 100-600K, but the adiabatic temperature change is 14K, which still has room for improvement.

[0004] The thermal conductivity of graphene can reach thousands, which is the required property of solid-state refrigeration material, but its high stress and high cost limit large-scale application. Therefore, researchers use paper-cut technology to modify graphene to form a graphene paper-cut configuration. This technology introduces an out-of-plane flipping region during stretching, greatly reducing the driving force of graphene. Introducing this new material into the field of solid-state refrigeration will be helpful to promote the practical process of solid-state refrigeration technology. SUMMARY

[0005] Invention purposes: In order to overcome the above shortcomings, the purpose of the present application is to provide a method for applying graphene paper-cut configuration in solid-state refrigeration, which can design graphene paper-cut configuration based on molecular dynamics simulation, calculate the key performance parameters of solid-state refrigeration materials and introduce this new material into the field of solid-state refrigeration.

[0006] To solve the above technical problems, the application provides a method for applying graphene paper-cut configuration in solid-state refrigeration, comprising:

[0007] Step S1: design the graphene paper-cut configuration;

[0008] Step S2: simulate the refrigeration cycle process: use molecular dynamics calculation to simulate the refrigeration cycle process of different graphene paper-cut configurations, and generate materials that can stably perform reversible refrigeration cycle;

[0009] Step S3: adiabatic temperature change test: count the adiabatic temperature change of the graphene paper-cut configuration during stretching and shrinking, and obtain the adiabatic temperature change data of the material;

[0010] Step S4: isothermal entropy change test: heat the material and calculate the specific heat capacity, and then calculate the isothermal entropy change in the refrigeration process through the Clausius-Clapeyron equation;

[0011] Step S5: refrigeration performance test: count the total energy change of the graphene paper-cut configuration during stretching and shrinking, obtain the input work data, and calculate the heat according to the temperature change and specific heat capacity through the definition of heat, and calculate the refrigeration performance according to the work and heat;

[0012] Step S6: driving pressure test: output the stress and strain curve by stretching at both ends, and obtain the driving pressure under different strains;

[0013] Step S7: calculate the thermal conductivity through the temperature gradient of heat conduction according to the method of non-equilibrium molecular dynamics.

[0014] In one aspect of the present application, in step S1, the application further comprises:

[0015] Step S11: design the cut graphene paper-cut configuration to reduce the driving force by paper-cut technology;

[0016] Step S12: construct a structure model and perform hydrogenation operation on the structure model;

[0017] Step S13: design multiple configurations using modeling software and compare the refrigeration performance parameters to screen and generate the optimal graphene paper-cut configuration.

[0018] In one aspect of the present application, in step S12, the hydrogenation operation comprises: adsorbing one hydrogen atom on the edge carbon atom to ensure that adjacent edge carbon atoms do not form a covalent bond during the stretching process.

[0019] In one aspect of the present application, in step S2, the application further comprises:

[0020] Step S21: selecting a preset potential function;

[0021] Step S22: setting the simulation box to apply periodic boundary conditions in the y and z directions, setting the x direction as the stretching direction and setting the x direction as the fixed boundary.

[0022] In one aspect of the present application, in step S2, the simulation process further comprises:

[0023] Step S23: giving each atom a velocity according to a Gaussian distribution to achieve a preset room temperature, and then using an isothermal-isobaric ensemble to relax the material at room temperature and normal pressure for a first preset time to stabilize the structure and converge energy, force and other parameters to a minimum value;

[0024] Step S24: performing a stretching process: using an isobaric-isenthalpic ensemble to stretch the graphene paper cutting configuration in the x direction;

[0025] Step S25: performing a heat release process: fixing the material position, using an isothermal-isobaric ensemble to return the material to a preset room temperature to simulate the release of heat generated by the material contacting a heat source;

[0026] Step S26: performing a shrinking process: using an isobaric-isenthalpic ensemble to shrink the graphene paper cutting configuration in the x direction;

[0027] Step S27: performing a heat absorption process: fixing the material position, using an isothermal-isobaric ensemble to return the material to a preset room temperature to simulate the absorption of heat generated by the material contacting a heat source.

[0028] In one aspect of the present application, in step S3, the application further comprises:

[0029] Step S31: counting the temperature change in the stretching process and the shrinking process and calculating the average value of the temperature change;

[0030] Step S32: counting the temperature in the interval at a second preset time interval to generate temperature change curves of different processes;

[0031] Step S33: calculating the actual adiabatic temperature change of the material according to the heat capacity correction.

[0032] In one aspect of the present application, in step S4, the application further comprises:

[0033] Step S41: simulate the temperature rising process: raise the temperature from the first preset temperature to the second preset temperature, count the change of the total energy of the material with the temperature rising, and set the slope as the specific heat capacity of the graphene paper-cut configuration;

[0034] Step S42: calculate the isothermal entropy change according to the Clapeyron equation C p is the specific heat capacity, ΔT is the adiabatic temperature change, T is the temperature.

[0035] In one aspect of the present application, in step S5, the application further comprises:

[0036] Step S51: count the total energy change of the graphene paper-cut configuration in the stretching and shrinking process and subtract the two to obtain the input work W ;

[0037] Step S52: obtain the heat by the heat definition , wherein, m is the mass, C p is the specific heat capacity ΔT is the adiabatic temperature change.

[0038] Step S53: calculate the refrigeration performance according to the work and heat .

[0039] In one aspect of the present application, in step S7, the application further comprises:

[0040] Step S71: according to the method of non-equilibrium molecular dynamics, count the heat transferred after the formation of a stable temperature gradient: ;

[0041] Step S72: calculate the thermal conductivity.

[0042] The present application also provides a graphene paper-cut configuration-based solid-state refrigeration application system, which adopts the above-mentioned graphene paper-cut configuration-based solid-state refrigeration application method, comprising:

[0043] A model design module for designing a graphene paper-cut configuration;

[0044] A refrigeration cycle module for simulating a refrigeration cycle process: using molecular dynamics calculation to simulate the refrigeration cycle process of different graphene paper-cut configurations, to generate materials capable of stably performing reversible refrigeration cycles;

[0045] An adiabatic temperature change module for adiabatic temperature change testing: counting the adiabatic temperature change of the graphene paper-cut configuration in the stretching and shrinking process to obtain the adiabatic temperature change data of the material.​

[0046] Isothermal entropy change module for isothermal entropy change test: the material is subjected to a heating process and the specific heat capacity is calculated, and then the isothermal entropy change in the refrigeration process is calculated through the Clausius Clapeyron equation;

[0047] Refrigeration test module for refrigeration performance test: the total energy change of the graphene paper cutting configuration in the stretching and shrinking process is counted to obtain the input work data, and the heat is calculated according to the temperature change and the specific heat capacity through the heat definition, and the refrigeration performance is calculated according to the work and heat;

[0048] Pressure test module for driving pressure test: the stress and strain curve is output by two-end stretching to obtain the driving pressure under different strain;

[0049] Thermal conductivity calculation module for calculating thermal conductivity according to the method of non-equilibrium molecular dynamics through the temperature gradient of heat conduction.

[0050] The above technical solutions of the present application have the following advantages compared with the prior art:

[0051] 1、The graphene paper cutting configuration of the present application can be used as a refrigeration working medium in solid-state refrigeration, which produces a thermal effect under single-axis stress driving to perform solid-state refrigeration; the graphene paper cutting configuration is a configuration obtained by cutting graphene, which can produce out-of-plane flipping after stretching.

[0052] 2、The graphene paper cutting configuration can produce an isothermal entropy change of 60 J·kg-1·K-1 under a pressure of less than 50 MPa, an adiabatic temperature change of 25 K, which is greater than the adiabatic temperature change value of 14 K obtained by existing paper folding configuration experiments, and the refrigeration interval of such material is large and does not depend on the phase transition point of the material, which can produce temperature change by stretching and compression in any temperature range, which is superior to other solid-state refrigeration material systems. At the same time, the thermal conductivity of such material is high, which can reach 62 W·m -1 ·K -1 Although the paper cutting structure weakens the thermal conductivity of graphene, it is still much higher than that of traditional solid-state refrigeration materials. The present application provides a powerful solution to replace traditional vapor compression technology, which makes the industrial application of solid-state refrigeration show broad prospects. It has broad application potential in many fields such as aerospace, space exploration, electronic equipment cooling, medical and biotechnology, and home appliance industry. BRIEF DESCRIPTION OF DRAWINGS

[0053] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or prior art description will be briefly introduced. Obviously, the drawings in the following description only constitute the embodiments of the present application, and for those skilled in the art, other drawings can be obtained without creative labor on the basis of the provided drawings.

[0054] Figure 1 is the first flowchart of the application method of the graphene paper-cutting configuration in solid-state refrigeration provided by the embodiment of the present application.

[0055] Figure 2 is the second flowchart of the application method of the graphene paper-cutting configuration in solid-state refrigeration provided by the embodiment of the present application.

[0056] Figure 3 is the model diagram of the graphene paper-cutting configuration provided by the embodiment of the present application.

[0057] Figure 4 is the refrigeration cycle diagram of the solid-state refrigeration technology provided by the embodiment of the present application.

[0058] Figure 5 is the adiabatic temperature change diagram of the graphene paper-cutting configuration stretching and compression process provided by the embodiment of the present application.

[0059] Figure 6 is the specific heat capacity diagram of the graphene paper-cutting configuration heating process provided by the embodiment of the present application.

[0060] Figure 7 is the energy change diagram of the graphene paper-cutting configuration stretching and compression process provided by the embodiment of the present application.

[0061] Figure 8 is the module connection diagram of the application system of the graphene paper-cutting configuration in solid-state refrigeration provided by the embodiment of the present application.

[0062] Description of the drawings:

[0063] 101, model design module, 102, refrigeration cycle module, 103, adiabatic temperature change module, 104, isothermal entropy change module, 105, refrigeration test module, 106, pressure test module, 107, thermal conductivity calculation module. DETAILED DESCRIPTION

[0064] Embodiments of the present application are described below in detail with reference to the accompanying drawings, examples of which are shown in the drawings, wherein the same or similar numerals represent the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by reference to the drawings are exemplary and are intended to explain the present application, and cannot be understood as a limitation of the present application.

[0065] The present application proposes an application method of graphene paper-cutting configuration in solid-state refrigeration, in order to obtain excellent comprehensive refrigeration performance in configuration materials. The described embodiments are only a part of the present application, not all. It should be noted that in the specific embodiments, the software calculation part involved is based on molecular dynamics, and the LAMMPS program commonly used in the industry is used for calculation, so as to obtain the data in each step of the present application efficiently and accurately.

[0066] Therefore, referring to Figure 1 and Figure 2 It is shown that in some embodiments, the application method of graphene paper-cutting configuration in solid-state refrigeration includes:

[0067] Step 1: Because the driving force during stretching of graphene is large, the designed cut graphene configuration can reduce the driving force through traditional paper-cutting technology.

[0068] Specifically, a variety of configurations are designed by using modeling software, and the refrigeration performance parameters are compared to obtain the optimal graphene configuration. That is, first, a graphene model with a length of 100 Å and a width of 48 Å is established, and a region with a length of 68 Å and a width of 4.8 Å is cut in the middle of the graphene. The cell is expanded by 721 to obtain the graphene configuration as shown in Figure 3 This configuration can ensure that the system produces out-of-plane deflection during the stretching process, reduces the driving force, and the small cutting area ensures the integrity of the graphene material to a certain extent, so that the material maintains a high thermal conductivity.

[0069] Step 2: Based on the configuration designed in step 1, a structure model is constructed using Materials Studio software and a hydrogenation operation is performed on the paper-cutting structure.

[0070] Specifically, one hydrogen atom is adsorbed on the edge carbon atom to ensure that adjacent edge carbon atoms will not form covalent bonds during the stretching process, which will affect the stretching process. A variety of materials designed by paper-cutting technology are exported as cif files, converted to data file format by ovito software, and molecular dynamics calculation is performed on the basis of the configuration to simulate the refrigeration process.

[0071] Step 3: Based on the structure model constructed by Materials Studio software in step 2, LAMMPS software is used to simulate the refrigeration cycle process of the graphene paper-cutting configuration.

[0072] Specifically, the in file, the potential function file and the structure data file are input files, the potential function uses the airebo potential function, which is more accurate for simulating carbon and hydrogen atoms, and the long-range van der Waals force and the Coulomb interaction are calculated by the particle-particle-particle grid k-space solver; the input file uses the isothermal-isobaric ensemble in the simulation, and the temperature and pressure are controlled by using the pressure regulation and temperature regulation techniques.

[0073] Among them, the simulation box is subjected to periodic boundary conditions in the y and z directions, and the x direction is set as a fixed boundary as the stretching direction; the integral uses the Verlet algorithm, and the time step is 1 fs.

[0074] Step 4: Based on the calculation details of step 3, an input file is written, which includes the relaxation process and the refrigeration cycle process, and the refrigeration cycle includes two adiabatic processes and two isothermal processes.

[0075] Specifically, after reading the structure file, the relaxation process assigns a velocity to each atom according to the Gaussian distribution, so that the whole reaches room temperature of 300K, and then uses the isothermal-isobaric ensemble to make the material relax at room temperature and normal pressure for 100 picoseconds, so that the structure is stable, and the energy, force and other parameters converge to the minimum value.

[0076] Step 5: According to the structure relaxed in step 4, the refrigeration cycle process is carried out, as shown in Figures 4-7 .

[0077] Specifically, the first cycle process is the stretching process, which is an adiabatic process, and uses the isobaric-isenthalpic ensemble to stretch the graphene paper cut configuration along the x direction. That is, the velocity command is used to give the atoms on the right side of the material a rightward velocity, so that the whole achieves the effect of left-end fixation and right-end stretching to the right, which does work on the material and makes the material temperature rise.

[0078] Specifically, the second cycle process is the heat release process, which is an isothermal process. The material position is fixed, and the isothermal-isobaric ensemble is used to make the material return to room temperature of 300K, which is the process of releasing the heat of the material in the simulation experiment in contact with the heat source, that is, the process of the air conditioner outdoor unit discharging heat in reality.

[0079] Specifically, the third cycle process is the contraction process, which is an adiabatic process, and uses the isobaric-isenthalpic ensemble to contract the graphene paper cut configuration along the-x direction, that is, the velocity command is used to give the atoms on the right side of the material a leftward velocity, so that the whole achieves the effect of the material on the right end shrinking to the left, which does work on the outside of the material and makes the material temperature decrease.

[0080] Specifically, the fourth cycle is the heat absorption process, which is an isothermal process. The material position is fixed, and the isothermal-isobaric ensemble is used to make the material return to room temperature of 300 K, which is in contact with the heat source in the experiment, and absorbs the heat of the relatively high temperature heat source, that is, the indoor refrigeration process of the air conditioner in reality.

[0081] The above four processes constitute the refrigeration cycle process of the solid-state refrigeration material, which reciprocates to achieve the effect of refrigeration.

[0082] Step 6: Simulate the temperature rising process of the material from 200 K to 400 K, and count the change of the total energy of the material with the increase of temperature, wherein the slope is approximately the specific heat capacity of the graphene paper cutting configuration. According to the shrinkage process, the temperature change of the graphene paper cutting technique is 7.94 K, that is, the adiabatic temperature change, and the specific heat capacity of the model is calculated to be 2266 J·kg -1 ·K -1 , and the specific heat capacity obtained by experiment is 700 J·kg -1 ·K -1 ; according to the proportional relationship, the adiabatic temperature change of the material can be corrected to 25 K. Through the Clausius-Clapeyron equation, the specific heat capacity, temperature change and other data of the system can be obtained. The isothermal entropy change of the material is 60 J·kg -1 ·K -1 , which are the key parameters for judging the performance of the solid-state refrigeration material.

[0083] Step 7: Count the total energy change in the stretching and shrinking processes, and subtract the input work W , and get the heat through the heat definition , wherein, m is the mass, C p is the specific heat capacity ΔT is the adiabatic temperature change; the refrigeration performance is calculated according to the work and heat. Thus, the COP of the graphene paper cutting configuration can reach 2.38.

[0084] Step 8: Use the deform command to stretch the material to both sides, and count the stress and strain data. Due to the existence of out-of-plane flipping, the strain is less than 30% of the stretching amount, and the strain of the material is much smaller than that of graphene itself, which fluctuates below 50 Mpa.

[0085] Step 9: Calculate the thermal conductivity according to the non-equilibrium molecular dynamics.

[0086] Specifically, the graphene paper-cut configuration is divided into 30 regions, the slowest atoms in the middle two regions are exchanged with the fastest atoms in the two end regions, so that the atoms in the middle region are fast and the atoms in the two side regions are slow, which is macroscopically represented as high temperature in the middle region and low temperature in the two side regions, forming a temperature gradient for heat transfer. After the stable temperature gradient is formed, the heat transferred is counted, The thermal conductivity of the material is calculated as 62 W·m -1 ·K -1 .

[0087] Therefore, by adopting the technical scheme, based on molecular dynamics simulation, the graphene paper-cut configuration is designed, the key performance parameters of solid-state refrigeration of the material, adiabatic temperature change, isothermal entropy change, refrigeration efficiency, driving force and thermal conductivity are calculated. A configuration with excellent comprehensive refrigeration performance is obtained, and the new material is introduced into the field of solid-state refrigeration, which is helpful for promoting the practical process of solid-state refrigeration technology.

[0088] Therefore, referring to Figure 8 , in some embodiments of the present application, a graphene paper-cut configuration based application system in solid-state refrigeration is also provided, which adopts the graphene paper-cut configuration based application method in solid-state refrigeration described above, including:

[0089] The model design module 101 is used for designing the graphene paper-cut configuration, and is also used for reducing the driving force by designing the cut graphene paper-cut configuration through the paper-cut technology, constructing a structure model and performing a hydrogenation operation on the structure model. The hydrogenation operation includes: adsorbing one hydrogen atom on the edge carbon atom to ensure that adjacent edge carbon atoms will not form a covalent bond during the stretching process; using modeling software to design multiple configurations and compare the refrigeration performance parameters to screen and generate the optimal graphene paper-cut configuration.

[0090] The refrigeration cycle module 102 is used for simulating a refrigeration cycle process: simulating the refrigeration cycle process of different graphene paper-cut configurations by using molecular dynamics calculation, generating materials capable of stably performing reversible refrigeration cycles; also used for selecting a preset potential function; setting a simulation box to apply periodic boundary conditions in the y and z directions, setting the x direction as the stretching direction and setting the x direction as a fixed boundary; step S23: giving each atom a velocity according to a Gaussian distribution, making the whole reach a preset room temperature, and then using an isothermal-isobaric ensemble to make the material relax at room temperature and normal pressure for a first preset time, making the structure stable, and the energy, force and other parameters converging to a minimum value; step S24: performing a stretching process: using an isobaric-isenthalpic ensemble to stretch the graphene paper-cut configuration along the x direction; step S25: performing a heat release process: fixing the material position unchanged, using an isothermal-isobaric ensemble to make the material return to the preset room temperature, to simulate the contact with the heat source in the experiment, and release the heat of warming the material; step S26: performing a shrinking process: using an isobaric-isenthalpic ensemble to shrink the graphene paper-cut configuration along the x direction; step S27: performing a heat absorption process: fixing the material position unchanged, using an isothermal-isobaric ensemble to make the material return to the preset room temperature, to simulate the contact with the heat source in the experiment, and absorb the heat of the relatively high-temperature heat source.

[0091] The adiabatic temperature change module 103 is used for adiabatic temperature change testing: statistically analyzing the adiabatic temperature change of the graphene paper-cut configuration in the stretching and shrinking processes, and obtaining the adiabatic temperature change data of the material; also used for statistically analyzing the temperature change in the stretching and shrinking processes and calculating the average value of the temperature change; statistically analyzing the temperature in the interval at intervals of a second preset time, generating the temperature change curve of different processes; according to the heat capacity correction, calculating the actual adiabatic temperature change of the material.

[0092] The isothermal entropy change module 104 is used for isothermal entropy change testing: performing a warming process on the material and calculating the specific heat capacity, and then calculating the isothermal entropy change in the refrigeration process through the Clausius-Clapeyron equation; also used for simulating a warming process: warming the temperature from a first preset temperature to a second preset temperature, statistically analyzing the change of the total energy of the material with the increase of the temperature, and setting the slope as the specific heat capacity of the graphene paper-cut configuration; according to the Clausius-Clapeyron equation calculating the isothermal entropy change, wherein C p is the specific heat capacity, ΔT is the adiabatic temperature change, T is the temperature.

[0093] The refrigeration testing module 105 is used for refrigeration performance testing: statistically analyzing the total energy change of the graphene paper-cut configuration in the stretching and shrinking processes, generating input work, and calculating the refrigeration performance according to the heat change, the specific heat capacity, the work done and the heat; also used for statistically analyzing the total energy change of the graphene paper-cut configuration in the stretching and shrinking processes and subtracting the two to obtain the input work W; heat definition get heat, where, m is mass, C p is specific heat capacity ΔT is adiabatic temperature change; calculate refrigeration performance according to work and heat .

[0094] Pressure test module 106, for driving pressure test: by two-end stretching, output stress and strain curve, get driving pressure at different strain.

[0095] Thermal conductivity calculation module 107, for calculating thermal conductivity according to the method of non-equilibrium molecular dynamics through the temperature gradient of heat conduction; also for calculating the heat transferred after forming a stable temperature gradient according to the method of non-equilibrium molecular dynamics: ; calculate thermal conductivity.

[0096] In the description of the present specification, the description of the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" and the like means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any appropriate manner in any one or more embodiments or examples. In addition, different embodiments or examples described in the present specification and the features of different embodiments or examples can be combined and combined by those skilled in the art without contradiction.

[0097] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limiting the present application, and those skilled in the art can make changes, modifications, replacements and variations to the above embodiments within the scope of the present application.

Claims

1. A method for application of graphene kirigami configuration in solid state refrigeration, characterized in that, The application comprises the following steps: Step S1: designing a graphene paper-cut configuration; Step S2: simulating a refrigeration cycle process: using molecular dynamics calculation to simulate the refrigeration cycle process of different graphene paper-cut configurations, and generating materials capable of stably performing reversible refrigeration cycles; Step S3: adiabatic temperature change test: statistically analyzing the adiabatic temperature change of the graphene paper-cut configuration during the stretching and shrinking processes, and obtaining the adiabatic temperature change data of the material; Step S4: isothermal entropy change test: performing a temperature rising process on the material and calculating the specific heat capacity, and then calculating the isothermal entropy change in the refrigeration process through the Clausius-Clapeyron equation; Step S5: refrigeration performance test: statistically analyzing the total energy change of the graphene paper-cut configuration during the stretching and shrinking processes, obtaining the input work data, and calculating the heat according to the temperature change and the specific heat capacity, and calculating the refrigeration performance according to the work and the heat; Step S6: driving pressure test: outputting the stress and strain curves through two-end stretching, and obtaining the driving pressure under different strains; Step S7: calculating the thermal conductivity through the temperature gradient of heat conduction according to the method of non-equilibrium molecular dynamics.

2. The method according to claim 1, wherein, In step S1, the application further comprises: Step S11: designing a cut graphene paper-cut configuration to reduce the driving force through the paper-cut technology; Step S12: constructing a structure model and performing a hydrogenation operation on the structure model; Step S13: designing multiple configurations using modeling software and comparing the refrigeration performance parameters to screen and generate an optimal graphene paper-cut configuration.

3. The method of claim 2, wherein the graphene kirigami configuration is used in solid-state refrigeration. In step S12, the hydrogenation operation comprises: adsorbing one hydrogen atom on the edge carbon atom to ensure that adjacent edge carbon atoms do not form covalent bonds during the stretching process.

4. The method of claim 1 or 2, wherein the graphene kirigami configuration is used in solid-state refrigeration. In step S2, the application further comprises: Step S21: selecting a preset potential function; Step S22: setting a simulation box to apply periodic boundary conditions in the y and z directions, setting the x direction as the stretching direction, and setting the x direction as a fixed boundary.

5. The method of claim 4, wherein the graphene kirigami configuration is used in solid-state refrigeration. In step S2, the simulation process further comprises: Step S23: giving each atom a velocity according to a Gaussian distribution to make the whole body reach a preset room temperature, and then using an isothermal-isobaric ensemble to make the material relax for a first preset time at room temperature and normal pressure, so that the structure is stable and the energy and force parameters converge to a minimum value; Step S24: performing a stretching process: using an isobaric-isenthalpic ensemble to stretch the graphene paper-cut configuration along the x direction; Step S25: performing a heat release process: fixing the material position unchanged, using an isothermal-isobaric ensemble to make the material return to the preset room temperature, to simulate the heat release when the material is in contact with a heat source during the experiment; Step S26: performing a shrinking process: using an isobaric-isenthalpic ensemble to shrink the graphene paper-cut configuration along the x direction; Step S27: performing a heat absorption process: fixing the material position unchanged, using an isothermal-isobaric ensemble to make the material return to the preset room temperature, to simulate the heat absorption when the material is in contact with a heat source during the experiment.

6. The method of claim 5, wherein the graphene kirigami configuration is used in solid-state refrigeration. In step S3, the application further comprises: Step S31: statistically analyzing the temperature change during the stretching and shrinking processes and calculating the average value of the temperature change; Step S32: statistically analyzing the temperature in the interval at intervals of a second preset time to generate temperature change curves of different processes; Step S33: Calculate the actual adiabatic temperature change of the material according to the heat capacity correction.

7. The method of claim 1 or 6, wherein the graphene kirigami configuration is used in solid-state refrigeration. In step S4, the application further comprises: Step S41: Simulate the temperature rising process: raise the temperature from the first preset temperature to the second preset temperature, count the change of the total energy of the material with the temperature rising, and set the slope as the specific heat capacity of the graphene paper-cut configuration; Step S42: Calculate the isothermal entropy change according to the Clausius-Clapeyron equation Calculate the isothermal entropy change, where C p is the specific heat capacity, ΔT is the adiabatic temperature change, T is the temperature.

8. The method of claim 7, wherein the graphene kirigami configuration is used in solid-state refrigeration. In step S5, the application further comprises: Step S51: Calculate the total energy change of the graphene kirigami configuration during the stretching and shrinking processes and subtract the two to obtain the input work W ; Step S52: Defining heat by temperature The heat is obtained, where, m is the mass, C p is the specific heat capacity ΔT is the adiabatic temperature change; Step S53: Calculate the refrigeration performance according to the work and heat .

9. The method of claim 1, wherein the graphene kirigami configuration is used in solid-state refrigeration. In step S7, the application further comprises: Step S71: According to the method of non-equilibrium molecular dynamics, the heat transferred after the stable temperature gradient is formed is counted: ; Step S72: Calculate the thermal conductivity.

10. A system for solid-state refrigeration based on graphene kirigami configuration, using the method for solid-state refrigeration based on graphene kirigami configuration according to any one of claims 1-9, characterized in that, Comprise: A model design module for designing a graphene paper-cut configuration; A refrigeration cycle module for simulating a refrigeration cycle process: using molecular dynamics calculation to simulate the refrigeration cycle process of different graphene paper-cut configurations, and generating materials capable of stably performing reversible refrigeration cycles; An adiabatic temperature change module for adiabatic temperature change test: counting the adiabatic temperature change of the graphene paper-cut configuration during stretching and shrinking, and obtaining the adiabatic temperature change data of the material; An isothermal entropy change module for isothermal entropy change test: performing a temperature rising process on the material and calculating the specific heat capacity, and then calculating the isothermal entropy change in the refrigeration process through the Clapeyron equation; A refrigeration test module for refrigeration performance test: counting the total energy change of the graphene paper-cut configuration during stretching and shrinking, obtaining the input work data, and calculating the heat according to the temperature change and the specific heat capacity through the heat definition, and calculating the refrigeration performance according to the work and the heat; A pressure test module for driving pressure test: outputting the stress and strain curve by stretching at both ends, and obtaining the driving pressure under different strains; A thermal conductivity calculation module for calculating the thermal conductivity through the temperature gradient of heat conduction according to the method of non-equilibrium molecular dynamics.

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