A solid-state magnetic refrigeration device operating in a single magnetic field and its application.

Abstract

This invention provides an all-solid-state magnetic refrigeration device, comprising an all-solid-state magnetic refrigeration device and a continuous magnetic field. The magnetic refrigeration device includes a refrigeration unit comprising a parallel-arranged refrigeration layer and a heat-conducting layer. The refrigeration layer includes multiple magnetic refrigeration plates embedded in an insulating material; the heat-conducting layer includes heat-conducting plates embedded in the insulating material. The refrigeration layer and the heat-conducting layer undergo reciprocating translational motion, allowing the heat-conducting plates to sequentially conduct heat to each of the multiple magnetic refrigeration plates. In one terminal state, the multiple magnetic refrigeration plates are within the continuous magnetic field, and in another terminal state, they are outside the continuous magnetic field. This invention achieves heat exchange directly between adjacent refrigeration and heat-conducting layers, eliminating the need for an external heat recovery module, thus eliminating irreversible heat recovery losses, increasing cooling power density, and requiring only a simple continuous magnetic field generated by a single magnet. This significantly reduces the requirements for the magnet, lowers costs, and simplifies device design.

Description

Technical Field

[0001] This invention belongs to the field of magnetic refrigeration technology, specifically relating to a high-efficiency reciprocating all-solid-state magnetic refrigeration device that utilizes a single magnetic field without the aid of a regenerator and its application. Background Technology

[0002] Magnetic refrigeration technology is a refrigeration technique that achieves cooling by causing entropy and temperature changes due to phase transitions in magnetic refrigeration materials during the application and demagnetization of a magnetic field. Traditional gas compression refrigeration processes require the use of large amounts of ozone-depleting and greenhouse-evolving refrigerants such as Freon; however, refrigeration machines utilizing magnetic refrigeration technology do not produce or use environmentally damaging chemicals, making magnetic refrigeration a green and environmentally friendly technology.

[0003] On the other hand, compared to gas compression refrigeration, magnetic refrigeration is more efficient and energy-saving, can be miniaturized, and produces no noise pollution. These advantages make magnetic refrigeration technology one of the ideal alternatives to traditional gas compression refrigeration.

[0004] Regenerators used in room temperature magnetic refrigerators can be divided into three types: external regenerators, internal regenerators, and active regenerators. In active regenerative cycles (AMR), the magnetic material serves as both the magnetic working fluid and the regenerating material. By reducing heat loss during the regeneration process, it has become the magnetic refrigeration cycle method with the highest energy utilization efficiency at present, and has been applied to many refrigeration cycles.

[0005] The initial traditional AMR cycle achieved heat exchange through fluid. However, to meet requirements such as non-conductivity or non-magnetism, the heat exchange fluid often sacrificed its high thermal conductivity, limiting the heat exchange rate and restricting the operating frequency of practical refrigeration devices to below 1 Hz. Pursuing higher operating frequencies would lead to insufficient heat conduction, thereby reducing the system's cooling capacity and efficiency. Furthermore, irreversible heat loss due to the temperature difference between the heat transfer fluid and the container wall, as well as the relatively coarse mechanical control devices, all have a significant impact on the device's cooling efficiency. In addition, the corrosion of the magnet and refrigerant by the heat exchange fluid also complicates the design of magnetic refrigeration devices, thus increasing their manufacturing costs.

[0006] To address a series of problems inherent in traditional AMR (Automatic Refrigerant Regulator) systems based on fluid heat transfer, novel all-solid-state magnetic refrigeration models utilizing high thermal conductivity solid heat transfer media for regeneration have attracted significant attention. Currently reported all-solid-state refrigeration models mainly fall into two categories: those based on thermal diodes (electrically controlled thermal diodes and magnetically controlled thermal diodes) and those based on high thermal conductivity materials. Among these, the all-solid-state magnetic refrigeration model based on thermal diodes, using Peltier elements (electrically controlled thermal diodes) as the solid heat transfer medium, requires a large operating current to accelerate heat transfer. This increases the overall power loss (i.e., external work) of the system, leading to a decrease in the COP (coefficient of performance) and cooling efficiency. While reducing the operating current can indeed reduce power loss, it also reduces heat transfer speed, cooling capacity, and operating frequency, contradicting the initial purpose of introducing the thermal diode. Therefore, while introducing Peltier elements can improve the operating frequency and cooling power of the all-solid-state magnetic refrigeration system, it inevitably introduces power loss, negatively impacting cooling efficiency. On the other hand, although the all-solid-state refrigeration model based on magnetron-controlled thermal diodes can achieve significant improvements in power density, COP, and refrigeration temperature range, it is difficult to obtain magnetron-controlled thermal diode materials that meet the requirements of practical applications.

[0007] Therefore, the limitations of heat exchange medium have greatly hindered the research, application and development of all-solid-state magnetic refrigeration models, and there is a need to develop new magnetic refrigeration devices that adopt more efficient heat recovery methods.

[0008] As a significant research advancement in this field, the applicant has proposed a reciprocating all-solid-state magnetic refrigeration device in another prior application, CN202110906753.9, which is currently unpublished. This magnetic refrigeration device includes at least one refrigeration unit comprising a parallel-arranged refrigeration layer and a heat-conducting layer. The refrigeration layer includes multiple magnetic refrigerant sheets spaced apart and embedded in an insulating material, while the heat-conducting layer includes multiple heat-conducting sheets spaced apart and embedded in an insulating material. The refrigeration and heat-conducting layers are capable of reciprocating translational motion in opposite directions, and there is thermal conduction between the magnetic refrigerant sheets and the heat-conducting sheets. While this device design achieves rapid heat recovery and improves heat exchange efficiency, it requires multiple heat-conducting sheets, roughly the same number as the magnetic refrigerant sheets, and its operation requires discontinuous segmented magnetic fields (i.e., multiple continuous magnetic fields generated by multiple magnets). Therefore, the device structure is relatively complex, and its production and operating costs are high, making industrialization difficult. Summary of the Invention

[0009] The purpose of this invention is to develop a high-efficiency all-solid-state magnetic refrigeration device that operates under a single magnetic field. By using a single magnet to generate a simple and continuous single magnetic field, the amount of heat-conducting working fluid used is reduced, and the device can operate at high frequency while having advantages such as simple device design, low processing and production costs, and a heat recovery factor greater than 1.

[0010] Among them, the heat recovery factor refers to the ratio of the temperature span between the hot and cold ends of the device when it reaches equilibrium (equilibrium temperature span) to the temperature change (adiabatic temperature change) when the magnetic refrigerant enters and exits the magnetic field.

[0011] Through long-term literature review and in-depth research, the inventors of this invention discovered that materials with high thermal conductivity, such as copper, silver, gold, aluminum, platinum, iron, graphene, diamond-aluminum alloys, or carbon nanotubes, can absorb or release heat in a relatively short time, making them ideal heat-conducting media. On the other hand, insulating materials such as glass fiber, asbestos, rock wool, silicates, aerogel felt, and vacuum plates can effectively prevent irrelevant heat exchange between the magnetic refrigerant / heat-conducting medium and the external environment, thereby reducing heat loss. Therefore, the inventors combined high thermal conductivity materials as heat-conducting media with magnetic refrigerant and insulating materials, achieving highly efficient all-solid-state magnetic refrigeration through rational device design. Furthermore, since the magnetic refrigerant, heat-conducting medium, and insulating material are all solid, they are easy to design and process into different shapes and sizes, and also facilitate precise control of mechanical devices. Therefore, all-solid-state refrigeration devices based on high thermal conductivity materials can achieve refrigeration of devices at different scales (e.g., submicron to meter).

[0012] The objective of this invention is achieved through the following technical solution.

[0013] This invention provides an all-solid-state magnetic refrigeration device, the device comprising an all-solid-state magnetic refrigeration component and a continuous magnetic field.

[0014] The magnetic refrigeration device includes at least one refrigeration unit, which includes a refrigeration layer and a heat-conducting layer arranged in parallel, wherein:

[0015] - The cooling layer includes a plurality of magnetic cooling working fluid sheets (or "magnetic cooling sheets") that are spaced apart and embedded in the first thermal insulation material;

[0016] - The thermally conductive layer includes a thermally conductive working fluid sheet (or "thermal conductive sheet") embedded in the second thermal insulation material.

[0017] The cooling unit is configured such that the cooling layer and the heat-conducting layer undergo reciprocating translational motion, allowing the heat-conducting working fluid sheet to sequentially conduct heat with each of the plurality of magnetic cooling working fluid sheets.

[0018] The continuous magnetic field is configured such that, in one terminal state of the reciprocating translational motion, the plurality of magnetic refrigerant plates are within the continuous magnetic field, while in another terminal state, the plurality of magnetic refrigerant plates are outside the continuous magnetic field.

[0019] According to the all-solid-state magnetic refrigeration device provided by the present invention, the regenerative factor of the magnetic refrigeration device is greater than 1.

[0020] According to the all-solid-state magnetic refrigeration device provided by the present invention, the magnetic refrigeration device further includes a cold end and a hot end, respectively, at two moving ends (both ends along the moving direction) of the heat-conducting layer, which conduct heat to the heat-conducting working fluid sheet. In a preferred embodiment of the present invention, the distance between the center of the continuous magnetic field and the hot end is less than the distance between the center and the cold end. That is, the position of the continuous magnetic field is closer to the hot end.

[0021] In some embodiments of the present invention, the thermally conductive layer may include a plurality of thermally conductive working fluid sheets. In this case, each of the plurality of thermally conductive working fluid sheets sequentially conducts heat with each of the plurality of magnetically refrigerated working fluid sheets; and each of the plurality of thermally conductive working fluid sheets sequentially conducts heat with the cold end and the hot end.

[0022] According to the all-solid-state magnetic refrigeration device provided by the present invention, during operation, a portion of the magnetic refrigeration device is placed in a continuous magnetic field. Preferably, 40% to 70% of the projected area of ​​the magnetic refrigeration device is placed in the magnetic field, more preferably 45% to 55% of the projected area of ​​the magnetic refrigeration device is placed in the magnetic field. In a most preferred embodiment, half (i.e., 50%) of the projected area of ​​the magnetic refrigeration device is placed in the magnetic field.

[0023] The continuous magnetic field is a common, simple magnetic field. Through reciprocating translational motion, each of the multiple magnetic refrigerant sheets in the cooling layer alternates between the magnetic field region and the non-magnetic field region. Furthermore, each magnetic refrigerant sheet interacts with the heat-conducting sheet of the heat-conducting layer, conducting heat. The heat-conducting sheet transfers heat absorbed from the cold end to the magnetic refrigerant sheet and, in turn, transfers heat from the magnetic refrigerant sheet to the hot end, forming a temperature gap and achieving cooling.

[0024] The magnetic field is preferably a uniform magnetic field with a strength of 0.1–60 T, preferably 1–2 T. The reciprocating frequency of the cooling layer is 0.01–1000 Hz, preferably 1–20 Hz, and the reciprocating frequency of the heat-conducting layer is also 0.01–1000 Hz, preferably 1–20 Hz. The reciprocating frequencies of the cooling layer and the heat-conducting layer are the same.

[0025] According to the all-solid-state magnetic refrigeration device provided by the present invention, the magnetic refrigeration working fluid sheet can be made of any magnetocaloric material, such as one or more selected from Gd, FeRh, LaFeSi, GdSiGe, MnAs, MnPSiGe and NiMnX, preferably Gd, Gd5(Si,Ge)4, or La(Fe,Si). 13 One or more of MnCoGe and NiMnSn.

[0026] According to the all-solid-state magnetic refrigeration device provided by the present invention, the heat-conducting working fluid sheet can be made of any heat-conducting material, such as copper, silver, gold, aluminum, platinum, iron, graphene, diamond aluminum alloy and carbon nanotubes, etc., preferably inexpensive and readily available materials such as copper and graphene.

[0027] According to the all-solid-state magnetic refrigeration device provided by the present invention, the first insulation material and the second insulation material may be the same or different, and may be independently selected from one or more of glass fiber, asbestos, rock wool, silicate, aerogel felt and vacuum plate.

[0028] The magnetic refrigerant sheet can be embedded in the first insulating material of the cooling layer or the thermally conductive sheet can be embedded in the second insulating material of the thermally conductive layer using any known method, such as bonding with epoxy resin adhesive. One or more cooling layers and one or more thermally conductive layers can be assembled together using any known method, as long as the cooling and thermally conductive layers can be independently translated; for example, each thermally conductive layer or each cooling layer can be individually controlled by a linear stepper motor.

[0029] In a preferred embodiment of the present invention, to achieve optimal thermal conductivity between the cooling layer and the thermally conductive layer and reduce additional losses due to frictional work, graphite powder or other thermally conductive material powder may be disposed between the cooling layer and the thermally conductive layer. Preferably, the distance between the cooling layer and the thermally conductive layer is 0–10 nm.

[0030] In some preferred embodiments of the present invention, the magnetic refrigerant sheet, the thermally conductive sheet, the first insulating material located between two adjacent magnetic refrigerant sheets, and the second insulating material located between two adjacent thermally conductive sheets have the same order of magnitude in size.

[0031] According to the reciprocating all-solid-state magnetic refrigeration device provided by the present invention, the number of refrigeration units can be selected from 1 to 100, preferably 2 to 25, depending on the actual refrigeration requirements.

[0032] This invention does not impose any particular limitation on the shape of the cooling layer, the heat-conducting layer, the magnetic refrigeration working fluid sheet, and the heat-conducting working fluid sheet. In a preferred embodiment, for ease of manufacturing and control of heat transfer, the cooling layer, the heat-conducting layer, the magnetic refrigeration working fluid sheet, and the heat-conducting working fluid sheet are all rectangular of the same size. Preferably, the plurality of magnetic refrigeration working fluid sheets are embedded at equal intervals in the first insulating material of the cooling layer. Preferably, the cooling layer includes 2 to 100 magnetic refrigeration working fluid sheets, more preferably 4 to 25. When the heat-conducting layer includes multiple heat-conducting working fluid sheets, the multiple heat-conducting working fluid sheets can be embedded at equal or non-equal intervals in the second insulating material of the heat-conducting layer. In a preferred embodiment of this invention, the heat-conducting layer includes one heat-conducting working fluid sheet.

[0033] On the other hand, the present invention also provides the application of the above-mentioned all-solid-state magnetic refrigeration device in refrigerators, air conditioners, liquefied gases and microelectronic device refrigeration.

[0034] Compared to the applicant's earlier application 202110906753.9, which required multiple magnets to generate multiple continuous magnetic fields, this invention only requires one magnet, achieving efficient operation with a heat recovery factor greater than 1 under a simple continuous magnetic field. This significantly reduces the requirements for the magnet and lowers production costs. Furthermore, the earlier application's thermal conductive layer requires multiple thermally conductive sheets to achieve the heat recovery function; while the thermal conductive layer of this invention can use only one thermally conductive sheet, greatly simplifying device design, reducing material requirements, and being more environmentally friendly. Attached Figure Description

[0035] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings, wherein:

[0036] Figure 1 , Figure 2 , Figure 3 and Figure 4 This is a schematic diagram illustrating the working principle of the all-solid-state magnetic refrigeration device of the present invention;

[0037] Figure 5 This is a schematic diagram of the mesh generation model of a single-magnet all-solid-state magnetic refrigeration device using rectangular cooling plates and heat-conducting plates in the finite element simulation of the embodiment.

[0038] Figure 6 This is a temperature diagram showing the temperature when the refrigeration modules and the hot and cold end modules of the single magnet magnetic refrigeration device in the embodiment reach equilibrium.

[0039] Figure 7 This is a data graph showing the effect of Cu thickness on the equilibrium temperature span of Gd in the magnetic refrigeration device of the present invention;

[0040] Figure 8 This is a data graph showing the influence of the operating frequency on the equilibrium temperature span of Gd in the magnetic refrigeration device of the present invention;

[0041] Figure 9 This is a data graph showing the effect of Ag thickness on the equilibrium temperature span of Gd in the magnetic refrigeration device of the present invention;

[0042] Figure 10 The effect of Cu thickness on La(Fe,Si) in the magnetic refrigeration device of this invention. 13 Data graph showing the effect of temperature span equilibrium. Detailed Implementation

[0043] The present invention will be further described in detail below with reference to specific embodiments. The embodiments given are only for illustrating the present invention and are not intended to limit the scope of the present invention.

[0044] For simplicity, let's take a magnetic refrigeration device with one cooling layer and one heat-conducting layer as an example, combined with... Figure 1 , Figure 2 , Figure 3 and Figure 4 The preferred operating mode and operating principle of the magnetic refrigeration device of the present invention will be described.

[0045] 1) Before the all-solid-state magnetic refrigeration device is put into operation, both the refrigeration layer and the heat-conducting layer are stationary at the moving end outside the magnetic field. At this time, the heat-conducting sheet of the heat-conducting layer is in full contact with the cold end, and the heat-conducting sheet is not in contact with the magnetic refrigeration sheet in the refrigeration layer. The multiple magnetic refrigeration sheets are separated by insulating material to maintain insulation. During operation, the refrigeration layer and the heat-conducting layer move back and forth independently in a certain order.

[0046] 2) A single continuous magnetic field is applied by a common permanent magnet or an electromagnet. The magnetic field region is constant and is set on one side near the hot end. The magnetic field region is preferably the length that can just accommodate all the magnetic cooling chips at the same time. In one terminal state, multiple magnetic cooling chips are in the magnetic field, while in another terminal state, multiple magnetic cooling chips are outside the magnetic field.

[0047] 3) Since the multiple magnetic cooling sheets in the cooling layer are separated by insulating material, there is no heat transfer between the multiple magnetic cooling sheets; heat transfer only exists between the cooling layer and the heat-conducting layer.

[0048] 4) The cold end and the hot end are respectively located at the two moving ends of the heat-conducting layer. Figure 1 The image shows the first state during device operation. At this time, the cooling layer moves from outside the magnetic field into the magnetic field, and the temperature of the magnetic cooling chip rises. The heat-conducting layer remains stationary, allowing sufficient heat conduction between the heat-conducting chip and the cold end. Figure 2 The image shows the second state during device operation. At this state, the cooling layer moves to the hot end and remains stationary; the heat-conducting layer moves from the cold end to the hot end, and during the movement, it sequentially contacts each magnetic cooling element of the cooling layer to absorb heat. Figure 3This is the third state in the device's operation. At this time, the heat-conducting layer moves to the hot end and remains stationary, making full contact with the hot end to conduct heat to it; the cooling layer moves to the cold end and leaves the magnetic field, and the temperature of the magnetic cooling chip decreases. Figure 4 The diagram shows the fourth state during device operation: the cooling layer moves to the cold end and remains stationary; the heat-conducting layer moves from the hot end to the cold end, contacting each magnetic cooling element in turn and transferring heat to it, thus lowering its own temperature. When it reaches the cold end, it makes full contact with the cold end and absorbs heat from it. This cycle repeats, causing the cold end temperature to decrease and the hot end temperature to increase, creating a temperature gap and achieving cooling.

[0049] 5) The hot end and cold end are connected to the outside world by a heat-conducting medium under the high thermal conductivity material to exchange heat, absorb heat from the cold source (i.e., cool the cold end) and release heat from the hot end to the surrounding environment.

[0050] In the all-solid-state magnetic refrigeration device of this invention, during the reciprocating motion of the heat-conducting layer, heat from the cold end is transferred to the hot end through a heat-conducting sheet with high thermal conductivity. Under no-load conditions, due to the mutual insulation between multiple cooling sheets in a single layer, a temperature gradient is formed between the cooling sheets. By increasing the number of cooling sheets, a cascade-like effect can be achieved, increasing the temperature range. Utilizing the high thermal conductivity of the heat-conducting layer, rapid heat recovery is achieved and heat exchange efficiency is improved, thus realizing highly efficient all-solid-state magnetic refrigeration under high-frequency operating conditions.

[0051] The specific all-solid-state magnetic refrigeration device in the embodiment is described below:

[0052] The all-solid-state magnetic refrigeration device comprises one or more rectangular cooling layers and one or more rectangular heat-conducting layers arranged in alternating layers. Each rectangular cooling layer includes multiple rectangular cooling plates and insulating material connecting them together. Each rectangular heat-conducting layer includes a rectangular heat-conducting plate and insulating material connecting them together. The rectangular cooling and heat-conducting layers can be sequentially translated along a certain direction. Half of the projected area of ​​this all-solid-state magnetic refrigeration device is placed in a magnetic field. If the shape is other irregular planar shapes, the rectangles can be replaced with corresponding shapes.

[0053] In this embodiment, finite element simulation is used to calculate the cooling temperature range and cooling efficiency of the single-magnet all-solid-state magnetic refrigeration device of the present invention during operation. The specific parameters are described below:

[0054] 1) Both the cooling layer and the heat-conducting layer are rectangular, and the total length of the device is 0.5mm to 10000mm, preferably 5 to 200mm. The side length of the cooling plate and the heat-conducting plate is 0.1mm to 100mm, preferably 1mm to 10mm. The thickness of each layer is selected according to actual needs, and can be 0.01mm to 50mm, preferably 0.1mm to 5mm.

[0055] 2) The cooling and heat-conducting layers are arranged alternately from top to bottom. Each cooling unit consists of two layers (one cooling layer and one heat-conducting layer). The number of cooling units stacked vertically can be selected from 1 to 100, or 2 to 200 layers, depending on the actual cooling requirements. Preferably, the number of cooling units stacked vertically is 2 to 25, or 4 to 50 layers. To achieve the alternating stacking arrangement, the number of rectangular cooling layers is within the range of ±1 of the number of rectangular heat-conducting layers. Preferably, the number of rectangular cooling layers is equal to the number of rectangular heat-conducting layers.

[0056] 3) Each heat-conducting layer has 1 heat-conducting module; each cooling layer preferably has 4 to 20 cooling modules, and the number can reach 100 depending on actual needs.

[0057] 4) The adiabatic module is replaced by an adiabatic boundary in the simulation.

[0058] 5) The adiabatic temperature change generated when the magnetic cooling element enters and leaves the magnetic field is selected to be 0.1 to 20 K.

[0059] 6) The software used for the finite element simulation was the solid heat transfer module in COMSOL Multiphysics 5.6.

[0060] 7) Depending on the actual cooling requirements, the initial temperature of the cooling layer and the heat-conducting layer is set to 0.1K to 1000K.

[0061] The following is a representative example to illustrate the simulation method of the "single magnet all-solid-state magnetic refrigeration device" of the present invention:

[0062] 1) Half of the model is located in a simple continuous magnetic field generated by a single magnet, and each cooling unit has one rectangular heat-conducting sheet in the heat-conducting layer.

[0063] 2) In the model, a refrigeration unit is simply composed of a layer of refrigerant and a layer of high thermal conductivity material. Each layer of the rectangular refrigeration module consists of 4 rectangular heat-conducting modules, and each layer consists of 1 rectangular heat-conducting module. Its geometric model is as follows: Figure 1 Two motion terminals and four motion steps, as follows Figure 1-4As shown. The initial temperature of all cooling and heat-conducting layers is set to 295K. The cold source and heat source are located at the two moving ends of the heat-conducting layer. When the cooling module moves to the right end, it enters a simple continuous magnetic field, and the temperature rises by 4K. Similarly, when the cooling module moves to the left end, it leaves the continuous magnetic field, and the temperature drops by 4K.

[0064] 3) Heat exchange occurs only when the magnetic cooling plate and the heat-conducting plate are in contact, and when the heat-conducting plate is in contact with the hot and cold ends; the remaining boundaries are adiabatic boundaries. To describe the translational reciprocating motion of the upper magnetic cooling medium and the lower heat-conducting medium, a dynamic mesh boundary condition is defined in the model. The upper cooling layer and the lower heat-conducting layer are set to reciprocate with a period of 10 seconds (frequency of 0.1 Hz), for a total of 100 cycles, and the total computation time domain is 1000 seconds.

[0065] 4) This model uses tetrahedral elements for free mesh generation, and the mesh model is as follows: Figure 5 As shown.

[0066] 5) This model adopts transient solution, with a calculation time domain of 10s as a cycle period, a time step of no more than 0.02s, and a total time of 1000s. It is solved by a direct strongly coupled solver combined with the nonlinear Newton iteration method, and the convergence factor is 0.01.

[0067] 6) Based on the finite element simulation model established above, and through initial parameter setting calculations, the temperature difference distribution of the refrigerant gradually stabilizes with continuous cycling. To more clearly show the temperature change of this all-solid-state magnetic refrigeration device over time, the temperature change curves of the hot and cold ends and each magnetic refrigeration element after stabilization are shown in the figure. Figure 6 In the diagram, the top and bottom horizontal lines represent the hot and cold ends, respectively. The four undulating curves in the middle correspond to the four magnetic cooling elements from right to left. The figure shows the results when the thickness of the magnetic cooling element Gd is 1 mm and the thickness of the heat-conducting element Cu is 0.6 mm. The hot end temperature stabilizes at approximately 298.3 K, and the cold end temperature stabilizes at approximately 293.3 K. The resulting 5 K temperature span corresponds to the four magnetic cooling elements. This represents the maximum no-load temperature span of the device when the adiabatic temperature of the magnetic cooling elements changes to 4 K.

[0068] 7) Based on the finite element simulation model established above, the heat recovery factor of the device was calculated for different thicknesses of the high thermal conductivity Cu material (0.1-1 mm). The heat recovery factor is defined as the ratio of the equilibrium temperature span to the adiabatic temperature change of the refrigerant. For example... Figure 7As shown, the thickness of Cu has a significant impact on the regenerative factor. When the copper thickness is very thin, the heat carrying capacity of Cu is low, limiting the heat transport efficiency and causing the regenerative factor to decrease. Similarly, when the copper thickness is relatively thick, the higher motion frequency leads to incomplete regeneration, resulting in a decrease in the regenerative factor. Therefore, there is an optimal thickness, which is 0.2 mm in this case, yielding a maximum regenerative factor of approximately 3.

[0069] 8) Based on the finite element simulation model established above, the thermal recovery factor of the device at different operating frequencies was calculated, such as... Figure 8 As shown, with a fixed Cu thickness of 0.2 mm, the heat recovery process becomes increasingly incomplete as the frequency increases, causing the heat recovery factor to continuously decrease. Therefore, if a higher heat recovery factor is desired, the operating frequency of the device can be appropriately reduced.

[0070] 9) Based on the finite element simulation model established above, change the types of secondary refrigerant and heat transfer fluid to further verify the influence of the device's cooling capacity and the thickness of the heat transfer layer on the heat recovery factor, such as... Figure 9 and Figure 10 As shown in the figure, it can be seen that the device does indeed have a high heat recovery factor, achieving high cooling efficiency.

[0071] The composition of the refrigerant and heat transfer medium used in each embodiment, the operating frequency, and the size of the all-solid-state refrigeration device model are described in detail in Table 1 below.

[0072] Table 1

[0073]

[0074] The number of plates refers to the number of magnetic cooling plates in each cooling layer or the number of heat-conducting plates in each heat-conducting layer; the adiabatic temperature change refers to the adiabatic temperature change generated when the cooling layer enters the magnetic field; CNT: carbon nanotubes; DA: diamond aluminum composite material, also known as diamond aluminum alloy.

[0075] Refrigeration performance simulation results

[0076] The magnetic refrigeration devices prepared in Examples 1-19 all exhibited good cooling effects. The simulation results of Examples 1-3 are given below as examples.

[0077] 1) No-load cooling temperature range

[0078] In Examples 1-3, the simple continuous magnetic field generated by a single magnet occupies half of the device area, there is one rectangular heat-conducting module and four rectangular cooling modules, and their geometric models are as follows: Figure 1As shown, the initial temperature of all cooling and heat-conducting layers is set to 295K. The cold and hot ends are located at the two moving ends of the heat-conducting layer. The temperature of the cooling module increases by 4K when it enters the magnetic field region and decreases by 4K when it leaves. As the cooling and heat-conducting layers reciprocate sequentially, the cooling module contacts the heat transfer material of the regenerating module for heat exchange, causing the temperature of each cooling and regenerating module to continuously change. With the cycle continuing, the temperature eventually stabilizes. The temperature difference between the hot and cold ends at steady state represents the maximum temperature range of the all-solid-state magnetic refrigeration model device under no-load conditions. Based on the established finite element simulation model, through initial parameter setting calculations, the temperature distribution of the refrigerant gradually stabilizes with continuous cycling.

[0079] To more clearly illustrate the temperature changes at steady state for the hot and cold ends and each refrigeration module, the temperature change curve over time at steady state in Example 1 is shown below. Figure 6 In the figure, the top and bottom horizontal lines represent the hot and cold ends, respectively. The four undulating curves in the middle correspond to the four cooling chips from right to left. As can be seen from the figure, the temperature of the hot end is stable at approximately 298.3K, and the temperature of the cold end is stable at approximately 293.3K. The resulting 5K temperature span corresponds to the four cooling chips. The maximum unloaded temperature span of the device is when the adiabatic temperature of the cooling chip changes to 4K, thus proving that the all-solid-state magnetic refrigeration device of the present invention can form a large refrigeration temperature span under limited adiabatic temperature changes.

[0080] 2) The effect of thermally conductive layer thickness on the heat recovery factor

[0081] The regenerative factor is defined as the ratio of the equilibrium temperature span to the adiabatic temperature change. To investigate the effect of the thermally conductive layer thickness on the regenerative factor, based on the established finite element simulation model, the maximum temperature span of the device in Example 1 was calculated for different Cu heat transfer layer thicknesses (0.1–1.0 mm). Figure 7 As shown, the thickness of Cu significantly affects the maximum temperature span at equilibrium. When the copper layer is very thin, Cu has a low heat carrying capacity and poor heat transport efficiency, leading to a decrease in the regeneration factor. Similarly, when the copper layer is relatively thick, the higher motion frequency causes incomplete regeneration, resulting in a lower equilibrium temperature span. Therefore, with a Gd layer thickness of 1.0 mm, we obtain the optimal Cu layer thickness as 0.2 mm, with a maximum regeneration factor of approximately 3.

[0082] To further verify that the device can achieve a relatively large heat recovery factor under a simple continuous magnetic field generated by a single magnet, based on the finite element simulation model established above, the heat recovery factors of the device in Examples 2 and 3 were further calculated under different thermally conductive layer thicknesses of 0.1–1.0 mm, as shown below. Figure 9 and Figure 10 As shown, it can be seen that when the thermally conductive layer is relatively thick, the heat recovery factor decreases due to the incomplete heat recovery process. Due to the influence of the material's heat transfer properties, there is no inflection point for the optimal thickness between 0.1mm and 1.0mm; the optimal thickness of the thermally conductive layer should be between 0 and 0.1mm. If processing costs are not a concern, the influence of the thermally conductive layer thickness between 0 and 0.1mm on the equilibrium temperature range can be further explored. From... Figure 9 As can be seen, the heat recovery factor of Example 2 can reach 3.5; from Figure 10 As can be seen from the data, the heat recovery factor of Example 3 can reach 4.

[0083] 3) The effect of operating frequency on regenerative factor

[0084] To investigate the influence of the operating frequency of the single-magnet all-solid-state magnetic refrigeration device of the present invention on the equilibrium temperature range, the number of refrigeration modules N established in Embodiment 1 above was used as a basis. S =4 (very easy to manufacture), ΔT MCE A finite element simulation model was created at 4K (easily obtainable through permanent magnets), with the thickness of the Cu heat-conducting layer set to 0.2mm, and the operating frequency varied. From... Figure 8 It can be seen that as the operating frequency increases, the regeneration process becomes increasingly incomplete, causing the regeneration factor to continuously decrease. Therefore, if only a large regeneration factor is desired, low-frequency operation can be adopted.

Claims

1. A solid-state magnetic refrigeration device, comprising a solid-state magnetic refrigeration component and a continuous magnetic field, in, The all-solid-state magnetic refrigeration device includes at least one refrigeration unit, which includes a refrigeration layer and a heat-conducting layer arranged in parallel, wherein: -The cooling layer includes a plurality of magnetic refrigerant sheets spaced apart and embedded in a first thermal insulation material; -The thermally conductive layer includes a thermally conductive working fluid sheet embedded in the second thermal insulation material; The all-solid-state magnetic refrigeration device further includes a cold end and a hot end, which conduct heat to the heat-conducting working fluid sheet at two moving ends of the heat-conducting layer, respectively. The refrigeration unit is configured such that the refrigeration layer and the heat-conducting layer undergo reciprocating translational motion, allowing the heat-conducting working fluid sheet to exchange heat sequentially with each of the plurality of magnetic refrigeration working fluid sheets. The continuous magnetic field is configured such that, in one terminal state of the reciprocating translational motion, the plurality of magnetic refrigerant plates are within the continuous magnetic field, while in another terminal state, the plurality of magnetic refrigerant plates are outside the continuous magnetic field.

2. The all-solid-state magnetic refrigeration device according to claim 1, wherein, The regenerative factor of the all-solid-state magnetic refrigeration device is greater than 1.

3. The all-solid-state magnetic refrigeration device according to claim 1, wherein, The distance between the center of the continuous magnetic field and the hot end is less than the distance between the center and the cold end.

4. The all-solid-state magnetic refrigeration device according to any one of claims 1, wherein, The thermally conductive layer includes one or more thermally conductive working fluid sheets, each of which sequentially conducts heat with each of the plurality of magnetic refrigeration working fluid sheets.

5. The all-solid-state magnetic refrigeration device according to claim 4, wherein the thermally conductive layer comprises a thermally conductive working fluid sheet.

6. The all-solid-state magnetic refrigeration device according to claim 1, wherein, The thermally conductive layer includes one or more thermally conductive working fluid sheets, each of which sequentially conducts heat to the cold end and the hot end.

7. The all-solid-state magnetic refrigeration device according to claim 1, wherein, The material of the magnetic refrigerant sheet is one or more of Gd, FeRh, LaFeSi, GdSiGe, MnAs, MnPSiGe and NiMnSn; The material of the thermally conductive working medium is one or more of copper, silver, gold, aluminum, platinum, iron, graphene, carbon nanotubes, and diamond-aluminum alloy. The first insulation material and the second insulation material may be the same or different, and each is independently selected from one or more of glass fiber, asbestos, rock wool, silicate, aerogel felt and vacuum plate.

8. The all-solid-state magnetic refrigeration device according to claim 1, wherein the material of the magnetic refrigeration working fluid is Gd, Gd5(Si,Ge)4, or La(Fe,Si). 13 One or more of MnCoGe and NiMnSn.

9. The all-solid-state magnetic refrigeration device according to claim 7, wherein the material of the thermally conductive working fluid sheet is copper or graphene.

10. The all-solid-state magnetic refrigeration device according to any one of claims 1 to 9, wherein, The distance between the cooling layer and the heat-conducting layer is 0~10nm.

11. The all-solid-state magnetic refrigeration device according to claim 10, wherein graphite powder is disposed between the refrigeration layer and the heat-conducting layer.

12. The all-solid-state magnetic refrigeration device according to any one of claims 1 to 9, wherein, The magnetic refrigeration device includes 1 to 100 refrigeration units.

13. The all-solid-state magnetic refrigeration device according to claim 12, wherein, The magnetic refrigeration device includes 2 to 25 refrigeration units.

14. The all-solid-state magnetic refrigeration device according to any one of claims 1 to 9, wherein, The cooling layer comprises 2 to 100 magnetic refrigerant sheets.

15. The all-solid-state magnetic refrigeration device according to claim 14, wherein, The cooling layer comprises 4 to 25 magnetic refrigerant sheets.

16. The application of the all-solid-state magnetic refrigeration device according to any one of claims 1 to 15 in the refrigeration of refrigerators, air conditioners, liquefied gases and microelectronic devices.

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