Magnetic refrigerating apparatus

Abstract

To provide a magnetic refrigerating device capable of realizing synchronization between rotation of a magnet and switching of a flow passage of a heat exchange fluid by a simple structure, and easy in adjustment in manufacturing.SOLUTION: The magnetic refrigeration device 1 is disposed between a first magnet 10A, a second magnet 10A disposed opposite to the first magnet 10B, a rotation mechanism 12 for rotating the first magnet 10A and the second magnet 10B, and the first magnet 10A and the second magnet 10B. And a magnetic valve 16 that switches the flow passage 15 by approaching the magneto-caloric element filling portion 14 by being attracted by the leakage magnetic flux when the leakage magnetic flux from the magneto-caloric element filling portion 14 is larger than a predetermined value and by separating from the magneto-caloric element filling portion 14 when the leakage magnetic flux is smaller than the predetermined value.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a magnetic refrigeration device. [Background technology]

[0002] Toward the realization of a sustainable society, highly efficient cooling devices with a small environmental impact are needed. Cooling devices are used in a variety of fields, such as air conditioning, refrigeration equipment for food, and cooling of various machine tools and equipment, and reducing their environmental impact is therefore important. Currently, cooling devices generally use a compression-expansion cycle of alternative fluorocarbon gases for cooling. Alternative fluorocarbon gases have a high global warming potential, raising concerns about their environmental impact. Magnetic refrigeration devices, which use the magnetocaloric effect of magnetic materials for cooling, are a type of device that can achieve cooling with a smaller environmental impact than cooling devices that use alternative fluorocarbon gases.

[0003] Prior art documents relating to magnetic refrigeration devices include, for example, Patent Documents 1 and 2.

[0004] 5 and 7 of Patent Document 1 show a magnetic refrigeration device (200) in which an upper magnetic field generating member (10) and a lower magnetic field generating member (20) are rotated around a rotation axis (60) by a rotation mechanism, and a magnetic working material having a magnetocaloric effect, which is filled in a filling container (80) placed in a spatial gap (50) between the upper magnetic field generating member (10) and the lower magnetic field generating member (20), is repeatedly excited and demagnetized at a constant cycle in accordance with the rotational movement.

[0005] Furthermore, FIG. 7 of Patent Document 1 describes that the flow path of the heat exchange fluid that exchanges heat with the magnetic working material is controlled by rotary valves (81 to 84) that are linked to the movement of the rotation mechanism.

[0006] The abstract of Patent Document 2 describes a magnetic refrigerator comprising: a housing; a plurality of heat exchangers fixed within the housing and filled with magnetic particles having a magnetocaloric effect; a rotary drive unit; a rotating shaft rotated by the rotary drive unit; a magnetic field generating means attached to the rotating shaft and applying or removing a magnetic field to the magnetic particles in the plurality of heat exchangers as the rotating shaft rotates; a refrigerant pump circulating a refrigerant as the rotating shaft rotates; a rotary refrigerant control valve controlling the supply and discharge of refrigerant between the plurality of heat exchangers as the rotating shaft rotates; and a refrigerant circuit formed by connecting the refrigerant pump, the rotary refrigerant control valve, the plurality of heat exchangers, a cooling unit, and a heat dissipation unit, wherein the application or removal of the magnetic field to the magnetic particles by the magnetic field generating means and the control of the supply and discharge of refrigerant between the plurality of heat exchangers by the rotary refrigerant control valve are configured to be synchronized.

[0007] Furthermore, in FIG. 2 and paragraph 0020 of Patent Document 2, it is described that a rotary refrigerant control valve (12) is provided in the housing (1), and that a square rotor (13) attached to a rotary shaft (4) is accommodated inside the housing (1) as shown in FIGS. 2(b) and 2(d), that the rotor (13) has sliding portions at each vertex of the square so as to slide in contact with the inner surface of the case of the rotary refrigerant control valve (12), and that the introduction and discharge of the refrigerant are controlled by the rotation of the rotor (13).

[0008] Furthermore, Figures 1 and 2 and paragraph 0026 of Patent Document 2 state that, by using one motor (2) and rotating the same rotating shaft (4), the application and removal of a magnetic field to the magnetic particles (6) by the permanent magnet (8) and the supply and discharge of refrigerant between the heat exchangers (5a to 5d) by the rotary refrigerant control valve (12) and the discharge of the refrigerant to the heat dissipation section or cooling section can be synchronized, thereby reducing the power consumption of the motor (2). [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Japanese Patent Application Laid-Open No. 2024-47959 [Patent Document 2] Japanese Patent Application Laid-Open No. 2006-283987 Summary of the Invention [Problem to be solved by the invention]

[0010] However, in the technique described in Patent Document 1, the rotation mechanism and the rotary valves (81-84) are provided separately, which poses a problem in that it is difficult to synchronize them.

[0011] On the other hand, in Patent Document 2, the permanent magnets 8 and the rotor 13 are rotated synchronously by the same rotating shaft 4. However, as can be seen from Figure 2 of Patent Document 2, the technique described in Patent Document 2 requires precise adjustment of the positional relationship (angle) between the rotor 13 and the permanent magnets 8 and the position of the flow path of the refrigerant 20, which poses a problem of difficulty in adjustment during manufacturing.

[0012] The problem to be solved by the present invention is to provide a magnetic refrigeration device that can achieve synchronization between the rotation of the magnet and the switching of the flow path of the heat exchange fluid with a simple structure and that can be easily adjusted during manufacturing. [Means for solving the problem]

[0013] In order to solve the above-mentioned problems, the magnetic refrigeration device of the present invention is characterized by having a first magnet, a second magnet arranged opposite the first magnet, a rotating mechanism for rotating the first magnet and the second magnet, a magnetocaloric element-filled section arranged between the first magnet and the second magnet and filled with a magnetic material having a magnetocaloric effect, a flow path for passing a fluid that exchanges heat with the magnetocaloric element-filled section, and a magnetic valve that switches the flow path by being attracted by the leakage magnetic flux and approaching the magnetocaloric element-filled section when the leakage magnetic flux from the magnetocaloric element-filled section is greater than a predetermined value, and by moving away from the magnetocaloric element-filled section when the leakage magnetic flux is less than the predetermined value. [Effects of the Invention]

[0014] According to the present invention, it is possible to realize a magnetic refrigeration device that can be easily adjusted during manufacture by using a simple structure to synchronize the rotation of the magnet with the switching of the flow path of the heat exchange fluid. [Brief explanation of the drawings]

[0015] [Figure 1] FIG. 3 is a cross-sectional view showing the magnetic valves in an approaching state in the magnetic refrigeration device according to the embodiment. [Figure 2] FIG. 3 is a cross-sectional view showing the magnetic valve in a separated state in the magnetic refrigeration device of the embodiment. [Figure 3] FIG. 2 is a top view of a magnetocaloric element container in the magnetic refrigeration apparatus according to the embodiment. [Figure 4] FIG. 2 is a top view showing the positional relationship of the main parts of the magnetic refrigeration device according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0016] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In each drawing and embodiment, the same or similar components are designated by the same reference numerals, and redundant explanations will be omitted.

[0017] FIG. 1 is a cross-sectional view showing the magnetic valves in an approaching state in a magnetic refrigeration apparatus according to an embodiment of the present invention.

[0018] The magnetic refrigeration device 1 of this embodiment includes a magnet 10, a magnetic yoke 11, a rotation mechanism 12, and a magnetocaloric element container 13.

[0019] The magnet 10 includes a first magnet 10A and a second magnet 10B disposed opposite the first magnet 10A. The magnet 10 is, for example, a permanent magnet, and generates a magnetic field in the gap between the first magnet 10A and the second magnet 10B. In this embodiment, there are two pairs of first magnets 10A and second magnets 10B, and the two first magnets 10A are connected by a magnetic yoke 11, and the two second magnets 10B are connected by another magnetic yoke 11, thereby forming a magnetic circuit. However, this is not limited to this, and there may be at least one pair of first magnets 10A and second magnets 10B.

[0020] The rotation mechanism 12 rotates the first magnet 10A and the second magnet 10B. In this embodiment, an example is shown in which the rotation mechanism 12 has a drive unit 12A and a rotation shaft 12B, and the rotation shaft 12B is connected to the magnetic yoke 11. In the rotation mechanism 12 of this embodiment, the drive unit 12A, which has, for example, a motor, rotates the rotation shaft 12B, thereby rotating the first magnet 10A and the second magnet 10B about the rotation shaft 12B via the magnetic yoke 11.

[0021] The magnetocaloric element container 13 has a magnetocaloric element-filled portion 14 , a flow path 15 , and a magnetic valve 16 .

[0022] The magnetocaloric element-filled section 14 is disposed between the first magnet 10A and the second magnet 10B and is filled with a magnetocaloric element, which is a magnetic material having a magnetocaloric effect. The magnetic material having a magnetocaloric effect can be, for example, a ferromagnetic material made of gadolinium or a metal compound containing gadolinium. It is also desirable that the magnetocaloric element-filled section 14 be filled with a granular magnetic material. It is also desirable that the magnetocaloric element-filled section 14 have a concave-convex structure 14A in a position facing the magnetic valve 16, which will be described later. The reasons and effects of these will be described later.

[0023] The flow path 15 passes a fluid that exchanges heat with the magnetocaloric element-filled portion 14. The flow path 15 has a first flow path 15A and a second flow path 15B, and the flow paths 15 are switched by a magnetic valve 16.

[0024] The magnetic valve 16 of this embodiment operates by utilizing leakage magnetic flux from the magnetocaloric element-filled portion 14. Specifically, when the leakage magnetic flux from the magnetocaloric element-filled portion 14 is greater than a predetermined value, the magnetic valve 16 is attracted by the leakage magnetic flux and approaches the magnetocaloric element-filled portion 14, and when the leakage magnetic flux is smaller than the predetermined value, the magnetic valve 16 moves away from the magnetocaloric element-filled portion 14, thereby switching the flow path 15.

[0025] More specifically, the magnetic valve 16 of this embodiment has, for example, a valve portion 16A that blocks the flow path 15, a valve portion magnetic body 16B that is attracted by leakage magnetic flux to bring the valve portion 16A closer to the magnetocaloric element-filled portion 14, and a spring 16C that moves the valve portion 16A away from the magnetocaloric element-filled portion 14. The valve portion magnetic body 16B is made of a magnetic body. The valve portion 16A is made of a material that is unlikely to chemically react with the heat exchange fluid.

[0026] 1, when a magnetic field is applied to the magnetocaloric element-filled portion 14 by the first magnet 10A and the second magnet 10B, leakage magnetic flux is generated from the magnetocaloric element-filled portion 14. This leakage magnetic flux attracts the valve portion magnetic body 16B, causing the valve portion 16A to approach the magnetocaloric element-filled portion 14, and the valve portion 16A opens the first flow path 15A and closes the second flow path 15B. This allows the flow path 15 to be switched.

[0027] Furthermore, when a magnetic field is applied to the magnetocaloric element-filled portion 14, ideally all of the magnetic field lines that arise from the magnet 10 toward the magnetocaloric element-filled portion 14 pass through the magnetocaloric element-filled portion 14, so there is a risk that a magnetic force sufficient to move the solenoid valve 16 will not be generated in the valve portion magnetic body 16B. In this case, by providing the magnetocaloric element-filled portion 14 with an uneven structure 14A, a structure that intentionally generates leakage magnetic flux can be created, making it possible to obtain a magnetic force sufficient to operate the solenoid valve 16.

[0028] Furthermore, when the magnetocaloric element-filled portion 14 is filled with a granular magnetic material, the surface is uneven, which generates leakage magnetic flux. Therefore, if the magnetic material filled in the magnetocaloric element-filled portion 14 is granular, the uneven structure 14A is not necessarily required. Even if the magnetic material filled in the magnetocaloric element-filled portion 14 is not granular, providing the uneven structure 14A as described above can generate leakage magnetic flux. Furthermore, if the magnetic material filled in the magnetocaloric element-filled portion 14 is granular but the leakage magnetic flux is weak, providing the uneven structure 14A can further strengthen the leakage magnetic flux.

[0029] FIG. 2 is a cross-sectional view showing the magnetic valve in the separated state in the magnetic refrigeration apparatus of the embodiment.

[0030] 2, when the first magnet 10A and the second magnet 10B are rotated by the rotation mechanism 12 and a magnetic field is no longer applied to the magnetocaloric element-filled portion 14, no leakage magnetic flux is generated from the magnetocaloric element-filled portion 14. Therefore, the spring 16C separates the valve portion 16A from the magnetocaloric element-filled portion 14, and the valve portion 16A closes the first flow path 15A and opens the second flow path 15B. This allows the flow path 15 to be switched.

[0031] As described above, according to the magnetic refrigeration device 1 of this embodiment, the strength of the leakage magnetic flux from the magnetocaloric element filled section 14 changes in synchronization with the rotation of the first magnet 10A and the second magnet 10B by the rotation mechanism 12, and the solenoid valve 16 operates in synchronization with the strength of the leakage magnetic flux, thereby switching the flow path 15. Therefore, according to this embodiment, synchronization between the rotation of the magnet 10 and the switching of the flow path 15 for the heat exchange fluid can be achieved with a simple structure, and a magnetic refrigeration device 1 that is easy to adjust during manufacture can be achieved.

[0032] FIG. 3 is a top view of the magnetocaloric element container in the magnetic refrigeration apparatus of the embodiment.

[0033] An example of the positional relationship between the magnetocaloric element-filled portion 14 and the heat exchange fluid flow path 15 in the magnetocaloric element container 13 will be described using FIG. 3. In this embodiment, the magnetocaloric element-filled portion 14 has a shape obtained by dividing a circle into four parts, and is provided in the magnetocaloric element container 13. Two first flow paths 15A and two second flow paths 15B are connected to each of the four magnetocaloric element-filled portions 14. The magnetic valve 16 shown in FIG. 1 is provided midway along the path leading to the magnetocaloric element-filled portion 14 for each of the first flow paths 15A and the second flow paths 15B. Note that the magnetocaloric element-filled portion 14 in this embodiment has a shape obtained by dividing a circle into four parts, but it may also be divided into eight or sixteen parts.

[0034] FIG. 4 is a top view showing the positional relationship of the main parts of the magnetic refrigeration device of the embodiment.

[0035] The positional relationship between the first magnet 10A and the magnetocaloric element-filled portion 14 will be explained using Figure 4. The magnetic yoke 11 connected to the rotation shaft 12B and the first magnet 10A rotate on the top surface of the magnetocaloric element container 13. The magnetocaloric element-filled portion 14 is provided in the area through which the first magnet 10A connected to the magnetic yoke 11 passes as it rotates.

[0036] Next, a heat exchange cycle for performing cooling using the magnetocaloric effect of the magnetic refrigeration device 1 of this embodiment will be specifically described.

[0037] The magnetocaloric element filled portion 14 is filled with a magnetic material having a magnetocaloric effect. This magnetic material is preferably a ferromagnetic material capable of generating a large magnetocaloric effect. It is also desirable that the Curie temperature of the magnetic material be near the temperature range that is the primary target of the magnetic refrigeration device 1. For example, when used near room temperature, using gadolinium, which has a Curie temperature of approximately 19°C, can generate a relatively large temperature change due to the magnetocaloric effect. Alternatively, a compound of gadolinium and another metal with an appropriate Curie temperature, or a lanthanum-silicon-iron compound, or any metal or metal compound or mixture thereof that has a large magnetocaloric effect near room temperature, can be used as the compound filled in the magnetocaloric element filled portion 14.

[0038] In the magnetic refrigeration device 1, a cooling cycle is realized by flowing a heat exchange fluid to perform heat exchange in accordance with temperature changes that occur when a magnetic field is applied to and removed from the magnetocaloric element-filled portion 14. This magnetic field is applied and removed by utilizing a magnetic field generated by a magnetic circuit composed of a magnetic yoke 11 connected to the rotating shaft 12B and a magnet 10 connected to the magnetic yoke 11, and the magnetic field is applied and removed by the rotation of the magnet 10. Here, the magnetic yoke 11 is made of iron or low-carbon steel with few impurities. To achieve high cooling performance, the magnet 10 must generate as strong a magnetic field as possible. Therefore, it is desirable to use a neodymium-based magnet or the like. Furthermore, to concentrate the magnetic flux as much as possible in the magnetocaloric element-filled portion 14, a magnetic circuit using, for example, a Halbach array may be configured.

[0039] Next, the heat exchange procedure during the magnetic refrigeration cycle will be described. When a magnetic field is applied to the magnetocaloric element-filled section 14 using the magnetic circuit described above, heat is generated due to the magnetocaloric effect. A first heat exchange fluid is then introduced into the magnetocaloric element-filled section 14 through the first flow path 15A, and the generated heat is exchanged with the first heat exchange fluid. Next, the magnetic circuit consisting of the magnetic yoke 11 and magnet 10 is rotated by the rotating shaft 12B. When the magnetic field applied to the magnetocaloric element-filled section 14 is removed, heat is absorbed due to the magnetocaloric effect. A second heat exchange fluid is then introduced into the magnetocaloric element-filled section 14 through the second flow path 15B, and heat exchange is performed. By repeatedly applying and removing the magnetic field and switching the flow path 15 in synchronization with this, the temperature of the first heat exchange fluid increases and the temperature of the second heat exchange fluid decreases, i.e., a magnetic refrigeration cycle is completed in which heat is transferred from the second heat exchange fluid to the first heat exchange fluid. The first heat exchange fluid is introduced into a heat exchanger for exhaust heat (not shown), and the second heat exchange fluid is introduced into a cold head (not shown).

[0040] The first and second heat exchange fluids are fluids capable of efficiently exchanging heat with the magnetocaloric element. While various liquids commonly used as refrigerants can be used, water, which has a low environmental impact, is desirable for the magnetic refrigeration device 1, which is intended for use at temperatures near room temperature. Furthermore, if the device is likely to be used at temperatures below 0°C, a mixture of ethylene glycol or the like may be used. Furthermore, if contact with a magnetic material having a magnetocaloric effect could result in the generation of reaction products such as rust, a rust inhibitor or the like may be added. The first and second heat exchange fluids are introduced and circulated into the magnetocaloric element-filled section 14 using a circulation pump or the like. Alternatively, the same heat exchange fluid may be circulated to function as the first heat exchange fluid in one region and as the second heat exchange fluid in another region.

[0041] In this way, in accordance with the application and removal of the magnetic field, it is necessary to switch the flow paths of the first heat exchange fluid and the second heat exchange fluid and introduce them into the magnetocaloric element-filled section 14. This switching can be performed at the timing when a sufficient magnetic field is applied to the magnetocaloric element-filled section 14 or when the magnetic field is sufficiently removed, thereby efficiently realizing the magnetic refrigeration cycle described above. To achieve this, the magnetic valve 16 described using Figures 1 and 2 is used. The operation of the magnetic valve 16 has already been explained, so a detailed description is omitted.

[0042] As in this embodiment, by configuring the magnetic refrigeration device 1 so that the magnetocaloric element container 13 has a built-in structure for switching the flow path 15 using the magnetic valve 16, heat exchange can be performed in accordance with the application and removal of a magnetic field, making it possible to approach a more ideal magnetic refrigeration cycle. Furthermore, the flow path 15 switching, which tends to have a complex structure because two systems of heat exchange fluid must be supplied to multiple magnetocaloric element-filled sections 14, can be realized in a simplified form with a relatively short flow path 15. As a result, a compact magnetic refrigeration device 1 with high cooling performance can be provided.

[0043] Although the embodiments of the present invention have been described above, the present invention is not limited to the configurations described in the embodiments, and various modifications are possible within the scope of the technical concept of the present invention. In addition, some or all of the configurations described in the embodiments may be combined and applied. [Explanation of symbols]

[0044] 1: Magnetic refrigeration device 10: Magnet 10A: First magnet 10B: Second magnet 11: Magnetic yoke 12: Rotation mechanism 12A: Drive unit 12B: Rotation axis 13: Magnetocaloric element container 14: Magnetocaloric element filling section 14A: Uneven structure 15: Flow path 15A: First flow path 15B: Second flow path 16: Magnetic valve 16A: Valve part 16B: Valve magnetic material 16C: Spring

Claims

1. A first magnet; a second magnet disposed opposite the first magnet; a rotation mechanism that rotates the first magnet and the second magnet; A magnetocaloric element filled portion disposed between the first magnet and the second magnet and filled with a magnetic material having a magnetocaloric effect; a flow path for passing a fluid that exchanges heat with the magnetocaloric element-filled portion; a magnetic valve that switches the flow path by being attracted by the leakage magnetic flux and approaching the magnetocaloric element-filled portion when the leakage magnetic flux from the magnetocaloric element-filled portion is greater than a predetermined value, and by moving away from the magnetocaloric element-filled portion when the leakage magnetic flux is less than the predetermined value.

2. In claim 1, The magnetic valve is characterized in that it has a valve portion that blocks the flow path, a valve portion magnetic body that is attracted by the leakage magnetic flux to bring the valve portion closer to the magnetocaloric element filled portion, and a spring that moves the valve portion away from the magnetocaloric element filled portion.

3. In claim 1, The magnetic refrigeration device is characterized in that the magnetocaloric element filled portion is filled with the magnetic material in granular form.

4. In claim 1, The magnetic refrigeration apparatus is characterized in that the magnetocaloric element filling portion is filled with a ferromagnetic material made of gadolinium or a metal compound containing gadolinium.

5. In claim 1, The magnetic refrigeration apparatus is characterized in that the magnetocaloric element-packed portion has an uneven structure at a position facing the magnetic valve.

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