Magnetic Refrigeration Device

Abstract

To shorten the start-up time of a magnetic refrigeration device and to exert an effective magnetocaloric effect by proper temperature control. [Solution] The magnetic refrigeration device has a magnetocaloric material enclosed section and an AMR unit with one end being a low-temperature end and the other end being a high-temperature end due to the AMR cycle; a low-temperature side heat exchanger disposed at the low-temperature end of the AMR unit; a first circulation flow path that flows a liquid heat medium from the low-temperature end to the high-temperature end of the AMR unit, and cools the liquid heat medium flowing out from the high-temperature end in a chiller and flows it into the low-temperature end, thereby controlling the temperature of the magnetocaloric material in the magnetocaloric material enclosed section; and a second circulation flow path that further cools the liquid heat medium cooled in the chiller in the low-temperature side heat exchanger and sends it to the object to be cooled, and returns the liquid heat medium that has exchanged heat in the object to be cooled to the chiller.

Description

[Technical Field]

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

[0002] Until now, vapor compression refrigeration, which utilizes the state change of refrigerants such as fluorocarbons and their alternatives, has been widely used in general-purpose refrigeration technology. However, as global environmental awareness grows, refrigeration technologies that do not use gases that have a negative impact on the global environment, such as fluorocarbons, are attracting attention. Natural refrigerants such as carbon dioxide are examples of refrigerants with a low environmental impact, but natural refrigerants have disadvantages such as the need for high-pressure design and high power consumption. Therefore, great expectations are placed on magnetic refrigeration as a refrigeration technology that has a low environmental impact and can eliminate the disadvantages of natural refrigerants.

[0003] Magnetic refrigeration utilizes the reversible phenomenon (magnetocaloric effect) in which magnetocaloric materials generate and absorb heat by changing the externally applied magnetic field in an adiabatic state. As a prior art, a refrigeration device that executes an AMR (Active Magnetic Refrigeration) cycle has been proposed (see Patent Document 1 below). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-204234 Summary of the Invention [Problem to be solved by the invention]

[0005] In the above-mentioned conventional technology, a certain time is required from the start of the AMR cycle until an effective low temperature edge is generated in the magnetocaloric material bed, which results in the problem of a time-consuming start-up time for the magnetic refrigerator to perform effective cooling.

[0006] Furthermore, in conventional technologies, the temperature of magnetocaloric materials is not properly controlled, which means that the magnetocaloric effect cannot be effectively achieved. In particular, in the case of magnetocaloric materials that perform well in the negative temperature range, the entire system must be placed in a cooled environment such as a freezer, which makes maintenance such as maintaining the operation of electronic devices including the control system difficult and requires significant costs for continued operation. Furthermore, in conventional technologies where temperature management is not properly performed, it is difficult to improve cooling efficiency and the cooling capacity sufficient to cool the object to be cooled to extremely low temperatures cannot be ensured.

[0007] The present invention was proposed to address these problems. Specifically, the objectives of the present invention are to shorten the start-up time of a magnetic refrigeration device, to achieve an effective magnetocaloric effect through appropriate temperature management, to enable continuous operation at low cost and with easy maintenance, and to ensure the cooling capacity to cool an object to cryogenic temperatures by increasing the cooling efficiency. [Means for solving the problem]

[0008] In order to solve such problems, the present invention has the following configuration. a first circulation flow path that allows a liquid heat medium to flow from the low-temperature end to the high-temperature end of the AMR unit, and that cools the liquid heat medium flowing out from the high-temperature end in a chiller and then flows into the low-temperature end, thereby controlling the temperature of the magnetocaloric material in the magnetocaloric material enclosing portion; and a second circulation flow path that further cools the liquid heat medium cooled in the chiller in the low-temperature side heat exchanger and sends it to the object to be cooled, and that returns the liquid heat medium that has exchanged heat with the object to be cooled to the chiller. [Effects of the Invention]

[0009] With a magnetic refrigeration device having these characteristics, the startup time for cooling can be shortened by using a chiller in combination. Furthermore, by properly managing the temperature of the magnetocaloric material using the liquid heat medium cooled by the chiller, an effective magnetocaloric effect can be achieved, facilitating maintenance and reducing operating costs. Furthermore, by adding magnetocaloric effect cooling to the chiller-assisted cooling of the liquid heat medium, cooling efficiency and capacity can be improved, allowing the object to be cooled to an even lower temperature. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is an explanatory diagram showing the overall configuration of a magnetic refrigeration device. [Figure 2] FIG. 2 is an explanatory diagram showing the configuration of a chiller. [Figure 3] FIG. 3 is an explanatory diagram showing the configuration of a low-temperature side heat exchanger. [Figure 4] An explanatory diagram (cross-sectional view) showing the double-pipe structure of the AMR unit. [Figure 5] An explanatory diagram (cross-sectional view) showing the triple-tube structure of the AMR unit. [Figure 6] An explanatory diagram (partial end view) showing the end structure of an AMR unit with a triple-tube structure. [Figure 7] FIG. 2 is an explanatory diagram showing the positions of sensors in the magnetic refrigeration device. [Figure 8] FIG. 2 is an explanatory diagram showing an example of the configuration of a flow rate control unit. [Figure 9] FIG. 2 is an explanatory diagram showing a control system of a magnetic refrigeration device. DETAILED DESCRIPTION OF THE INVENTION

[0011] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the same reference numerals in different drawings denote parts with the same functions, and duplicated descriptions in each drawing will be omitted as appropriate.

[0012] The magnetic refrigeration device 1 shown in Figure 1 cools an object (hereinafter referred to as the object to be cooled Co) by utilizing the magnetocaloric effect. The magnetocaloric effect (MCE) is a phenomenon in which a magnetic material generates or absorbs heat when a magnetic field is applied to or removed from the magnetic material, and special materials that cause a significant temperature change are called magnetocaloric materials. Typical magnetocaloric materials that exhibit the magnetocaloric effect in the negative temperature range include gadolinium (Gd) and paramagnetic salts (Ce2Mg3(NO3) 12 ) are examples of paramagnetic materials. These materials are said to have high cooling efficiency because the magnetic entropy changes significantly with changes in the magnetic field at low temperatures.

[0013] The main component of the magnetic refrigeration device 1 is the AMR unit 10. The AMR unit 10 includes a magnetocaloric material enclosure 11 in which the above-mentioned magnetocaloric material is enclosed, and by executing the AMR cycle, a temperature gradient is generated in which one end of the magnetocaloric material enclosure 11 becomes a low-temperature end and the other end becomes a high-temperature end.

[0014] The AMR cycle is an operating cycle in which magnetization (application of a magnetic field) and demagnetization (removal of the magnetic field) of the magnetocaloric material are synchronized with the reciprocating movement of the working fluid passing through the inside of the magnetocaloric material enclosing portion 11. According to the AMR cycle, the working fluid in the magnetocaloric material enclosing portion 11 is moved to the high temperature end at the timing when the magnetocaloric material generates heat due to excitation of the magnetocaloric material, and the working fluid in the magnetocaloric material enclosing portion 11 is moved to the low temperature end at the timing when the magnetocaloric material absorbs heat due to demagnetization of the magnetocaloric material, and this operation is repeated.

[0015] In order for the AMR unit 10 to execute the AMR cycle, it is equipped with a closed flow path 12 for flowing a working fluid inside the magnetocaloric material confinement portion 11, a flow direction changer 13 for reciprocating the working fluid inside the magnetocaloric material confinement portion 11, a magnetic field generator 14 for magnetizing and demagnetizing the magnetocaloric material, and a control device 100 for synchronously operating the flow direction changer 13 and the magnetic field generator 14. The working fluid flowing through the magnetocaloric material confinement portion 11 and the closed flow path 12 is a liquid with a large heat capacity and high thermal conductivity (for example, water or an ethylene glycol aqueous solution). The working fluid may be a single type of liquid, or different liquids may be used for the high-temperature end, intermediate end, and low-temperature end of the magnetocaloric material confinement portion 11.

[0016] A piston pump, a double piston pump, a diaphragm pump, etc. can be used as the flow direction changer 13. The flow direction changer 13 causes the working fluid flowing through the magnetocaloric material enclosing portion 11 and the closed flow path 12 to move back and forth as shown by arrows L0 in the figure.

[0017] The magnetic field generator 14, which is driven in synchronization with the operation of the flow direction changer 13, can be a magnet rotation type that rotates a rotatable permanent magnet, or an electromagnet type that turns on / off the current to a coil wound around a magnetic body. When the magnetic field generator 14 excites the magnetocaloric material, the flow direction changer 13 switches the flow of the working fluid to the high temperature end, and when the magnetic field generator 14 demagnetizes the magnetocaloric material, the flow direction changer 13 switches the flow of the working fluid to the low temperature end.

[0018] The AMR unit 10 is provided with a low-temperature side heat exchanger 16 at the low-temperature end of a magnetocaloric material confinement section 11 generated by the AMR cycle, and a heat dissipation section (high-temperature side heat exchanger) 17 at the high-temperature end of the magnetocaloric material confinement section 11. The magnetocaloric material confinement section 11 is a tubular member in which a magnetocaloric material is confined, and filters 11A and 11B through which the working fluid described above passes are provided at both ends. The low-temperature side heat exchanger 16 is provided in contact with the outside of filter 11A, and the heat dissipation section 17 is provided in contact with the outside of filter 11B.

[0019] One end of the closed flow path 12 through which the working fluid flows is connected to the low-temperature end of the magnetocaloric material enclosing portion 11 via a low-temperature side heat exchanger 16. The other end of the closed flow path 12 is connected to the high-temperature end of the magnetocaloric material enclosing portion 11 via a heat dissipation portion 17. The working fluid that flows to the low-temperature end of the magnetocaloric material enclosing portion 11 passes through a filter 11A and the low-temperature side heat exchanger 16 and flows into the closed flow path 12, and the working fluid that flows to the high-temperature end of the magnetocaloric material enclosing portion 11 passes through a filter 11B and the heat dissipation portion 17 and flows into the closed flow path 12.

[0020] On the other hand, the magnetic refrigeration device 1 is equipped with a circulation flow path that circulates a liquid heat medium (circulating liquid). The liquid heat medium in the magnetic refrigeration device 1 has two functions. One is to control the temperature of the magnetocaloric material in the magnetocaloric material enclosing portion 11 at an appropriate temperature, and the other is to cool the object to be cooled Co by the liquid heat medium cooled in the low-temperature side heat exchanger 16. The liquid heat medium is cooled by the chiller 2 and circulates through the first circulation flow path 21 and the second circulation flow path 22.

[0021] The liquid heat medium that controls the temperature of the magnetocaloric material in the magnetocaloric material confinement portion 11 is cooled to an appropriate temperature by the chiller 2 and returns to the chiller 2 via a first circulation flow path 21 that passes around the outer periphery of the magnetocaloric material confinement portion 11 in the AMR unit 10. The flow of the liquid heat medium in the first circulation flow path 21 is indicated by arrow L1 in the figure. The first circulation flow path 21 allows the liquid heat medium to flow from the low-temperature end to the high-temperature end of the AMR unit 10, and also allows the liquid heat medium that flows out from the high-temperature end of the AMR unit 10 to be cooled by the chiller 2 and then flows into the low-temperature end of the AMR unit 10.

[0022] On the other hand, the liquid heat medium for cooling the object to be cooled Co is cooled in the chiller 2, passes through the second circulation flow path 22 and passes through the low-temperature side heat exchanger 16 to be further cooled and sent to the object to be cooled Co. The liquid heat medium that has exchanged heat with the object to be cooled Co flows back to the chiller 2 through the second circulation flow path 22. The flow of the liquid heat medium in the second circulation flow path 22 is indicated by arrow L2 in the figure.

[0023] In the illustrated example, the first circulation flow path 21 and the second circulation flow path 22 merge to form a single flow path before the return port 2P of the chiller 2, and then branch off to form separate flow paths after the discharge port 2Q of the chiller 2. However, the first circulation flow path 21 and the second circulation flow path 22 may be provided separately for the chiller 2, or a separate chiller 2 may be provided for each of the individual first circulation flow path 21 and second circulation flow path 22.

[0024] As shown in Fig. 2, the chiller 2 circulates the liquid heat medium stored in the cooling tank 2A ​​through the first circulation flow path 21 and the second circulation flow path 22 using a pump 2B to return the liquid heat medium to the cooling tank 2A. The liquid heat medium is returned to the chiller 2 from a return port 2P and discharged from a discharge port 2Q. The liquid heat medium stored in the cooling tank 2A ​​is maintained at an appropriate temperature (for example, -20°C) by an evaporator (heat absorber) 20A of the refrigerant circuit 20. The refrigerant circuit 20 constitutes a well-known refrigeration cycle equipped with the above-mentioned evaporator 20A, compressor 20B, condenser (heat radiator) 20C, and expansion valve 20D.

[0025] As shown in Fig. 3, the low-temperature side heat exchanger 16 described above has a separate flow path 16A through which the working fluid flows and a flow path 16B through which the liquid heat transfer medium of the second circulation flow path 22 flows. In the illustrated example, the flow path 16A through which the working fluid flows and the flow path 16B through which the liquid heat transfer medium flows intersect and are arranged in layers with a heat transfer plate 16C interposed therebetween. The low-temperature side heat exchanger 16 performs heat exchange with the low-temperature end of the magnetocaloric material enclosing portion 11, and the cooled working fluid moving toward the low-temperature end passes through the flow path 16A, thereby exhibiting a high heat absorption function. Furthermore, the low-temperature side heat exchanger 16 has the flow path 16A through which the working fluid passes intersect with the flow path 16B through which the liquid heat transfer medium passes, thereby increasing the heat exchange capacity for cooling the liquid heat transfer medium.

[0026] 4, the specific structure of the AMR unit 10 can be a double-pipe structure including an inner pipe portion 10A through which the aforementioned working fluid flows, and an outer pipe portion 10B that fits around the outer periphery of the inner pipe portion 10A. The inner pipe portion 10A forms a magnetocaloric material confinement portion 11 in which particles of the magnetocaloric material M are confined within the pipe. The gap between the inner pipe portion 10A and the outer pipe portion 10B forms part of a first circulation flow path 21 that circulates the liquid heat transfer medium.

[0027] The material of the inner pipe portion 10A is required to have high thermal conductivity in order to efficiently transfer the heat of the liquid heat medium flowing outside it to the magnetocaloric material M. Furthermore, since the magnetic field generator (magnet, etc.) 14A of the magnetic field generator 14 is arranged outside the outer pipe portion 10B, the inner pipe portion 10A is required to be a non-magnetic, low-magnetic permeability material that does not interfere with the magnetization and demagnetization of the magnetocaloric material M. Taking these factors into consideration, aluminum or copper is suitable as the material for the inner pipe portion 10A.

[0028] On the other hand, the material for the outer tube portion 10B is required to be a non-magnetic, low-magnetic permeability material that does not block the magnetic field of the magnetic field generator 14A, just like the inner tube portion 10A, but it is required to have strength characteristics as a housing member rather than thermoelectric conductivity. For this reason, the material for the outer tube portion 10B is preferably aluminum of a specified thickness or austenitic (non-magnetic) stainless steel (such as SUS304).

[0029] As shown in Fig. 5, the AMR unit 10 may have a triple-pipe structure. Similar to the example shown in Fig. 4, the example shown in Fig. 5 includes an inner pipe portion 10A in which a magnetocaloric material M is sealed and through which a working fluid flows, and an intermediate pipe portion 10C for forming a first circulation flow path 21 for circulating the liquid heat transfer medium on the outer periphery of the inner pipe portion 10A. An outermost pipe portion 10D for forming a vacuum insulation layer 10V is then provided on the outer periphery of the intermediate pipe portion 10C, resulting in a triple-pipe structure.

[0030] In the case of such a triple-tube structure, the material for the inner tube portion 10A is required to be a non-magnetic, low-magnetic permeability material that does not interfere with the magnetization and demagnetization of the magnetocaloric material M by the magnetic field generator 14A, as in the double-tube structure described above, and therefore aluminum or copper is suitable. On the other hand, the intermediate tube portion 10C and the outermost tube portion 10D are required to be a non-magnetic, low-magnetic permeability material with sufficient strength, as in the outer tube portion 10B in the double-tube structure, and therefore aluminum of a specified thickness or austenitic (non-magnetic) stainless steel (such as SUS304) is suitable.

[0031] When the AMR unit 10 has a triple-pipe structure, it is preferable to make the distance between the inner pipe portion 10A and the intermediate pipe portion 10C and the distance between the intermediate pipe portion 10C and the outermost pipe portion 10D as short as possible in order to efficiently magnetize and demagnetize the magnetocaloric material M sealed inside the inner pipe portion 10A. The distance between the inner pipe portion 10A and the intermediate pipe portion 10C is a gap for forming the first circulation flow path 21, so it is preferable to make it as short as possible without interfering with the smooth circulation of the heat liquid medium. Furthermore, the distance between the intermediate pipe portion 10C and the outermost pipe portion 10D is a space for forming the vacuum insulation layer 10V, so it is preferable to make it as short as possible within a range that allows the vacuum insulation layer 10V to effectively retain the low temperature generated in the AMR unit 10.

[0032] FIG. 6 shows a configuration example of an AMR unit 10 with a triple-pipe structure. In the illustrated example, when connecting the end of the intermediate pipe section 10C to the inner pipe section 10A, a bellows structure B1 is added near the connection end to disperse thermal stress generated by the temperature gradient of the AMR unit 10. When the end of the intermediate pipe section 10C is connected to the inner pipe section 10A via the bellows structure B1, a connecting pipe 21A is provided to penetrate the intermediate pipe section 10C and the outermost pipe section 10D to form a first circulation flow path 21 for flowing a liquid heat transfer medium inside the intermediate pipe section 10C. When the end of the outermost pipe section 10D is connected to the intermediate pipe section 10C via the bellows structure B2, connecting pipes 22A and 22B are provided to the low-temperature side heat exchanger 16 by penetrating the inner pipe section 10A, the intermediate pipe section 10C, and the outermost pipe section 10D to pass the liquid heat transfer medium of the second circulation flow path 22 to the low-temperature side heat exchanger 16. Incidentally, the inner pipe portion 10A has a filter 11A side sandwiching the low-temperature side heat exchanger 16, which serves as the magnetocaloric material enclosed portion 11, and a closed flow path 12 on the opposite side of the filter 11A.

[0033] As shown in Fig. 7, the magnetic refrigeration device 1 is equipped with sensors in various parts, allowing it to monitor the operating status and appropriately control the operation of the parts to be controlled. In Fig. 7, a temperature sensor S1 measures the temperature of the object to be cooled Co, and the operation of the magnetic refrigeration device 1 is controlled so that the detection result of the temperature sensor S1 approaches the target cooling temperature.

[0034] The temperature sensor S2 is installed upstream of the object to be cooled Co in the second circulation flow path 22, and detects the temperature of the liquid heat medium sent to the object to be cooled Co. The temperature sensor S2 can detect changes in the temperature of the liquid heat medium sent to the object to be cooled Co, and the start-up state of the magnetic refrigeration device 1 can be grasped.

[0035] The flow rate sensor S3 is provided upstream of the low-temperature side heat exchanger 16 in the second circulation flow path 22, and detects the flow rate of the liquid heat medium sent to the low-temperature side heat exchanger 16. The flow rate of the liquid heat medium sent to the low-temperature side heat exchanger 16 can be controlled by a flow rate control unit 3 provided upstream of the flow rate sensor S3.

[0036] The temperature sensor S4 detects the temperature of the liquid heat medium coming out of the cooling tank 2A ​​of the chiller 2. The liquid heat medium coming out of the chiller 2 and sent to the outer periphery of the magnetocaloric material enclosing portion 11 through the first circulation flow path 21 is controlled to a temperature necessary to maintain the magnetocaloric material in the magnetocaloric material enclosing portion 11 at an appropriate temperature. The temperature of the cooling tank 2A ​​can be adjusted by controlling the compressor 20B of the refrigerant circuit 20.

[0037] The magnetic sensor S5 detects the magnetized or demagnetized state of the magnetocaloric material in the magnetocaloric material enclosure 11. To detect the demagnetization (heat absorption) timing of the magnetocaloric material using the magnetic sensor S5, it is necessary to capture the moment when the magnetocaloric material transitions from a magnetized state to a non-magnetized state with high sensitivity and in real time. Suitable magnetic sensors S5 for this purpose include magnetoresistive sensors (MR sensors), Hall sensors, and fluxgate sensors. Based on the detection results of the magnetic sensor S5, the flow direction changer 13 and the flow restriction valve 4 are controlled. The flow restriction valve 4 is installed in the closed flow path 12 and restricts the flow of the working fluid so that it flows to the low-temperature end only when the magnetocaloric material is demagnetized (heat absorption).

[0038] The flow rate control unit 3 described above is provided in the second circulation flow path 22 to control the cooling efficiency of the magnetic refrigeration device 1. There is a close relationship between the flow rate of the liquid heat medium and the cooling effect, and if the heat exchange capacity of the low-temperature side heat exchanger 16 is sufficient, the faster the flow rate of the liquid heat medium flowing through the second circulation flow path 22, the higher the cooling efficiency of the object to be cooled Co. The basic flow rate of the circulation flow rate through the second circulation flow path 22 is determined by the pump capacity of the chiller 2, but by increasing the flow rate of the liquid heat medium using the flow rate control unit 3, the liquid heat medium cooled via the low-temperature side heat exchanger 16 can be efficiently supplied to the object to be cooled Co.

[0039] As shown in FIG. 8, the configuration of the flow rate control unit 3 is such that by providing one or both of a Venturi tube structure 3A and an orifice structure 3B in the second circulation flow path 22, the flow rate on the downstream side thereof can be increased. As shown in the drawing, in the flow rate control unit 3, when both the Venturi tube structure 3A and the orifice structure 3B are provided, the flow rate V1 on the upstream side of the flow rate control unit 3 is increased to a flow rate V2 (V1 < V2) by the Venturi tube structure 3A, and further increased to a flow rate V3 (V2 < V3) by the orifice structure 3B. In particular, the orifice structure 3B can variably control the flow rate by continuously changing the opening diameter through which the liquid heat medium passes by means of a shutter member 3S. By providing such a flow rate control unit 3 at a plurality of locations with respect to the second circulation flow path 22, multi-stage flow rate adjustment becomes possible, and the flow rate of the liquid heat medium can be appropriately adjusted so as to quickly converge to the target cooling temperature with respect to the object to be cooled Co.

[0040] The control system of the magnetic refrigeration apparatus 1 will be described with reference to FIG. 9. The magnetic refrigeration apparatus 1 can improve the startup characteristics, improve the cooling efficiency, and enhance the cooling capacity by performing operation control based on the detection values of the sensors described above. Here, the central management control by the control device 100 will be described. The control device 100 is a so-called computer, and as basic elements, includes a processor 101, a memory 102, an input unit 103, and an output unit 104, and these are connected to each other so as to be communicable via a bus 110.

[0041] Specifically, the processor 101 may be a CPU (Central Processing Unit), MPU (Micro Processing Unit), GPU (Graphics Processing Unit), DSP (Digital Signal Processor), SoC (System on a Chip), or the like, and may be configured with multiple processors of the same or different types. The memory 102 includes a ROM (Read Only Memory), a RAM (Random Access Memory), and storage. The ROM and storage store programs and various data, and the RAM serves as a working area for the processor 101 and temporarily stores programs, data, and arithmetic processing results. The processor 101 executes arithmetic processing for various controls. That is, the processor 101 reads the programs and data stored in the memory 102, and, based on the programs and data, determines control signals corresponding to the detection results of various sensors input to the input unit 103, and outputs the control signals from the output unit 104 to each control target.

[0042] 7, and includes a temperature sensor S1 for detecting the temperature of the object to be cooled Co, a temperature sensor S2 for detecting the temperature of the liquid heat medium sent to the object to be cooled Co, a flow rate sensor S3 for detecting the flow rate of the liquid heat medium sent to the low-temperature side heat exchanger 16, a temperature sensor S4 for detecting the temperature of the liquid heat medium exiting the chiller 2, and a magnetic sensor S5 for detecting the magnetized / demagnetized state of the magnetocaloric material in the magnetocaloric material sealing portion 11. In contrast, the controlled objects of the magnetic refrigeration apparatus 1 for which a control signal is output from the output portion 104 include the flow direction changer 13, the magnetic field generator 14, the chiller 2 (compressor 20B), the flow rate control portion 3, the flow regulating valve 4, etc.

[0043] The control device 100 (processor 101) first controls the chiller 2 to control the temperature of the liquid heat medium coming out of the chiller 2, thereby adjusting the temperature of the liquid heat medium passing through the first circulation flow path 21 and the outer periphery of the magnetocaloric material enclosing portion 11 to an appropriate temperature, and performs temperature management so that the magnetocaloric material in the magnetocaloric material enclosing portion 11 effectively exerts its magnetocaloric effect. As an example, if a material that exerts its effect in a low-temperature environment is selected as the magnetocaloric material, the liquid heat medium coming out of the chiller 2 is cooled to about -20°C.

[0044] The control device 100 (processor 101) then executes the AMR cycle to steadily operate the magnetic refrigeration device 1. At this time, the control device 100 (processor 101) synchronously drives the flow direction changer 13 and the magnetic field generator 14 to move the working fluid in the AMR unit 10 toward the high temperature end at the timing of magnetizing the magnetocaloric material, and to move the working fluid in the AMR unit 10 toward the low temperature end at the timing of demagnetizing the magnetocaloric material. In addition to this control, by operating the flow restriction valve 4 at the demagnetization timing detected by the magnetic sensor S5, the working fluid can be reliably moved toward the low temperature end at the demagnetization timing, and the rise time required to generate the low temperature end can be further shortened.

[0045] When the operation of the AMR unit 10 reaches a steady state, the liquid heat medium cooled in the chiller 2 passes through the second circulation flow path 22 and passes through the low-temperature side heat exchanger 16, where it is further cooled to an extremely low temperature state and sent to the object to be cooled Co. As an example, the liquid heat medium cooled to about -20°C in the chiller 2 can be cooled to about -40°C by heat exchange in the low-temperature side heat exchanger 16.

[0046] The control device 100 (processor 101) controls the operation of the magnetic refrigeration device 1 until the temperature of the object to be cooled Co detected by the temperature sensor S1 reaches the set target cooling temperature. At this time, the liquid heat transfer medium supplied to the object to be cooled Co is assisted by cooling from the chiller 2, and by adding cooling by the magnetocaloric effect due to the operation of the AMR unit 10, the object to be cooled Co can be quickly cooled to the target cooling temperature. This shortens the start-up time until the magnetic refrigeration device 1 can perform its effective cooling function.

[0047] In addition, when cooling the liquid heat transfer medium sent to the object to be cooled Co through the second circulation flow path 22, the control device 100 (processor 101) can appropriately improve the cooling efficiency and cooling capacity by combining the combination of cooling by the chiller 2 and cooling by the magnetocaloric effect by the AMR unit 10 with flow rate control by the flow rate control unit 3.

[0048] Specifically, when the target cooling temperature is relatively high, in order to reduce energy consumption and improve cooling efficiency, cooling efficiency is improved by suppressing cooling by the magnetocaloric effect, which has a high energy load, and increasing the proportion of cooling by chiller 2, while effectively employing flow rate control.On the other hand, when the target cooling temperature is extremely low, cooling efficiency is improved by effectively employing flow rate control, while increasing cooling capacity by making full use of cooling by chiller 2 and cooling by the magnetocaloric effect.

[0049] The features of the magnetic refrigeration device 1 can be summarized as follows. The magnetic refrigeration device 1 is equipped with a low-temperature side heat exchanger 16 disposed at the low-temperature end of the AMR unit 10, a first circulation flow path 21 that allows a liquid heat medium to flow from the low-temperature end to the high-temperature end of the AMR unit 10, and that cools the liquid heat medium flowing out from the high-temperature end in a chiller 2 and allows it to flow into the low-temperature end, thereby controlling the temperature of the magnetocaloric material in the magnetocaloric material enclosure 11, and a second circulation flow path 22 that further cools the liquid heat medium cooled in the chiller 2 in the low-temperature side heat exchanger 16 and sends it to the object to be cooled Co, and returns the liquid heat medium that has exchanged heat with the object to be cooled Co to the chiller 2.

[0050] According to this, by providing the first circulation flow path 21, the temperature of the magnetocaloric material can be appropriately controlled by the liquid heat medium cooled in the chiller 2, and an effective magnetocaloric effect can be exhibited. Furthermore, by providing the second circulation flow path 22, the liquid heat medium cooled in the chiller 2 is further cooled in the low-temperature side heat exchanger 16, and therefore high cooling capacity can be exhibited. Furthermore, since both the liquid heat medium flowing through the first circulation flow path 21 and the second circulation flow path 22 are returned to the chiller 2, cooling in the chiller 2 is always added, and cooling efficiency is improved. Furthermore, since the temperature of the magnetocaloric material is controlled by the liquid heat medium cooled in the chiller 2, there is no need to place the entire system in a cooled environment, which facilitates maintenance and reduces operating costs.

[0051] In order to perform the AMR cycle, the magnetic refrigeration device 1 is equipped with a closed flow path 12 that causes the working fluid to flow inside the magnetocaloric material sealing section 11, and a flow direction changer 13 that causes the working fluid to move back and forth within the closed flow path 12, and one end of the closed flow path 12 is connected to the low-temperature end side of the magnetocaloric material sealing section 11 via a low-temperature side heat exchanger 16.

[0052] According to this, the working fluid reciprocating in the flow direction changer 13 flows at a low temperature in the low-temperature side heat exchanger 16, which has been cooled by heat conduction from the low-temperature end of the magnetocaloric material enclosing portion 11, so that the low-temperature side heat exchanger 16 can cool the liquid heat medium flowing therethrough with its high heat absorption function. In the low-temperature side heat exchanger 16, the flow path 16B through which the liquid heat medium of the second circulation flow path 22 flows and the flow path 16A through which the working fluid flows are arranged separately, so that the working fluid and the liquid heat medium exchange heat with each other without being mixed, and can each perform their own unique functions.

[0053] In the magnetic refrigeration device 1, the AMR unit 10 has a double-pipe structure, and an outer pipe 10B is formed along the outer periphery of the inner pipe 10A that constitutes the magnetocaloric material confinement portion 11, forming a part of the first circulation flow path 21. This allows the liquid-separated heat transfer medium to flow over an extended distance of the inner pipe 10A, enabling efficient temperature control of the magnetocaloric material M in the magnetocaloric material confinement portion 11.

[0054] In the magnetic refrigeration device 1, by making the AMR unit 10 a triple-pipe structure, an intermediate pipe section 10C that forms part of the first circulation flow path 21 and an outermost pipe section 10D that forms a vacuum insulation layer 10V are formed along the outer periphery of the inner pipe section 10A that constitutes the magnetocaloric material confinement section 11. This allows a liquid-separated heat transfer medium to flow over the extended distance of the inner pipe section 10A, enabling efficient temperature control of the magnetocaloric material M in the magnetocaloric material confinement section 11, and also allows the vacuum insulation layer 10V to be formed over the extended distance of the inner pipe section 10A, effectively insulating the periphery of the magnetocaloric material confinement section 11.

[0055] In the magnetic refrigeration device 1, the first circulation flow path 21 and the second circulation flow path 22 join together to form a single flow path before the return port 2P of the chiller 2, and then branch off to form separate flow paths after the discharge port 2Q of the chiller 2. This allows a single chiller 2 to cool the liquid heat medium flowing through the first circulation flow path 21 and the liquid heat medium flowing through the second circulation flow path. Therefore, a single chiller 2 can efficiently manage the temperature of the magnetocaloric material M by the liquid heat medium flowing through the first circulation flow path 21, and assist-cool the object to be cooled Co by the liquid heat medium flowing through the second circulation flow path 22.

[0056] In the magnetic refrigeration device 1, a flow rate control unit 3 is provided in the second circulation flow path 22, and the flow rate control unit 3 controls the flow rate of the liquid heat medium sent to the object to be cooled Co via the low-temperature side heat exchanger 16. This makes it possible to effectively improve the cooling efficiency and cooling capacity by controlling the flow rate of the liquid heat medium.

[0057] Although the embodiments of the present invention have been described in detail above with reference to the drawings, the specific configurations are not limited to these embodiments, and the present invention also includes design changes within the scope of the present invention. Furthermore, the above-described embodiments can be combined by utilizing each other's technologies as long as there are no particular contradictions or problems in their purposes, configurations, etc. [Explanation of symbols]

[0058] 1: Magnetic refrigeration device 10: AMR unit 10A: Inner pipe section 10B: Outer pipe section 10C: Middle tube section 10D: Outermost tube section 10V: Vacuum insulation layer 11: Magnetocaloric material sealing section 11A, 11B: Filter 12: Closed flow path 13: Flow direction converter 14: Magnetic field generator 14A: Magnetic field generator 16: Low temperature side heat exchanger 16A, 16B: Flow path 16C: Heat transfer plate 17: Heat radiation part (high temperature side heat exchanger) 2: Chiller 2A: Cooling tank 2B: Pump 20: Refrigerant circuit 20A: Evaporator 20B: Compressor 20C: Condenser 20D: Expansion valve 21: First circulation flow path 22: Second circulation flow path 22A, 22B: Connection pipes 3: Flow velocity control section 3A: Venturi tube structure 3B: Orifice structure 3S: Shutter member 4: Flow control valve M: Magnetocaloric material B1, B2: Bellows structure S1, S2, S4: Temperature sensors S3: Flow rate sensor S5: Magnetic sensor 100: Control device 101: Processor 102: Memory 103: Input section 104: Output section 110: Bus

Claims

1. A magnetic refrigeration device that cools an object using the magnetocaloric effect, an AMR unit including a magnetocaloric material enclosure, one end of which becomes a low temperature end and the other end of which becomes a high temperature end through an AMR cycle; a low-temperature side heat exchanger disposed at a low-temperature end of the AMR unit; a first circulation flow path for flowing a liquid heat transfer medium from the low temperature end to the high temperature end of the AMR unit, and for cooling the liquid heat transfer medium flowing out from the high temperature end with a chiller and for flowing the liquid heat transfer medium into the low temperature end, thereby controlling the temperature of the magnetocaloric material in the magnetocaloric material sealing portion; A magnetic refrigeration apparatus comprising a second circulation flow path that further cools the liquid heat medium cooled in the chiller in the low-temperature side heat exchanger and sends it to an object to be cooled, and returns the liquid heat medium that has exchanged heat in the object to be cooled to the chiller.

2. a closed flow path for causing a working fluid to flow inside the magnetocaloric material confinement portion, and a flow direction changer for causing the working fluid to reciprocate within the closed flow path, in order to perform the AMR cycle; One end of the closed flow path is connected to the low-temperature end side of the magnetocaloric material sealing portion via the low-temperature side heat exchanger.

2. The magnetic refrigeration device according to claim 1.

3. In the low-temperature side heat exchanger, a flow path through which the liquid heat medium flows and a flow path through which the working fluid flows are arranged separately from each other in the second circulation flow path.

3. The magnetic refrigeration device according to claim 2.

4. the AMR unit has a double-pipe structure including an inner pipe portion constituting the magnetocaloric material confinement portion and an outer pipe portion along the outer periphery of the inner pipe portion, and a portion between the inner pipe portion and the outer pipe portion forms part of the first circulation flow path; 2. The magnetic refrigeration device according to claim 1.

5. the AMR unit has a triple-tube structure including an inner tube portion constituting the magnetocaloric material confinement portion, an intermediate tube portion along the outer periphery of the inner tube portion, and an outermost tube portion along the outer periphery of the intermediate tube portion, The space between the inner pipe portion and the intermediate pipe portion forms part of the first circulation flow path, A vacuum insulation layer is formed between the intermediate pipe portion and the outermost pipe portion.

2. The magnetic refrigeration device according to claim 1.

6. The first circulation flow path and the second circulation flow path merge to form one flow path before a liquid heat medium return port of the chiller, and branch to form respective flow paths after a liquid heat medium discharge port of the chiller.

2. The magnetic refrigeration device according to claim 1.

7. a flow rate control unit provided in the second circulation flow path, the flow rate of the liquid heat transfer medium being sent to the object to be cooled via the low-temperature side heat exchanger being controlled by the flow rate control unit; 2. The magnetic refrigeration device according to claim 1.

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