Magnetic Refrigeration Device

Abstract

The thermal insulation of the magnetic refrigerator will be improved to enhance the cooling effect. The structure will also be able to accommodate the thermal expansion and contraction of the piping that accompanies cooling. [Solution] The magnetic refrigeration device comprises a magnetic refrigeration unit with a magnetocaloric material enclosed section, and a heat medium circulation flow path that supplies the liquid heat medium cooled by the magnetic refrigeration unit to an object to be cooled and returns the liquid heat medium that has exchanged heat with the object to be cooled to the liquid heat medium cooling section, and the magnetocaloric material enclosed section is formed in the inner pipe section of a double pipe structure with a spatial insulation layer formed around it.

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 a reversible phenomenon (magnetocaloric effect) in which the temperature of a magnetocaloric material changes when an externally applied magnetic field is changed in an adiabatic state. For example, Patent Document 1 discloses a technology in which the magnetic field is changed to demagnetize the magnetocaloric material, and a low-temperature circulating fluid is generated by an endothermic reaction accompanying the demagnetization, thereby cooling a specimen (a target to be cooled) (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, even if the liquid heat medium is cooled by the magnetocaloric effect, there was a problem in that the cooling effect was deteriorated due to heat absorption in the circulation path of the liquid heat medium, particularly in the magnetocaloric material encapsulation section in which the magnetocaloric material is encapsulated.

[0006] Furthermore, in the conventional technology, no special measures were taken to prevent the expansion and contraction of the pipes through which the liquid heat transfer medium flows due to cooling, so in environments where temperatures are -20°C or even lower, there is a risk of damage to the pipes through which the liquid heat transfer medium flows due to thermal stress or thermal distortion.This has led to the problem that the technology cannot be used as is.

[0007] Furthermore, while magnetocaloric materials effectively exhibit the magnetocaloric effect below a certain temperature, conventional technologies have had the problem that the magnetocaloric effect cannot be effectively exhibited because it takes time for the magnetocaloric material to cool to the specified temperature. In particular, in the case of magnetocaloric materials that exhibit performance in the negative temperature range, it is necessary to place the entire system 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 a great deal of cost for continued operation.

[0008] The present invention has been proposed to address these problems. Specifically, the objectives of the present invention are to improve the cooling effect of a magnetic refrigerator, ensure the cooling capacity to cool an object to cryogenic temperatures, enable operation in low-temperature environments such as -20°C, and shorten the time it takes for a magnetocaloric material to cool to a predetermined temperature, thereby enabling the magnetocaloric effect to be effectively exerted. [Means for solving the problem]

[0009] In order to solve such problems, the present invention has the following configuration. A magnetic refrigeration device that cools an object by utilizing the magnetocaloric effect, comprising: a magnetic refrigeration unit having a magnetocaloric material enclosed portion; and a heat medium circulation flow path that supplies a liquid heat medium cooled by the magnetic refrigeration unit to the object to be cooled and returns the liquid heat medium that has undergone heat exchange with the object to be cooled to a chiller, wherein the magnetocaloric material enclosed portion is formed in the inner pipe portion of a double pipe structure with a spatial insulation layer formed around it. [Effects of the Invention]

[0010] In a magnetic refrigeration device having such characteristics, the magnetocaloric material enclosed section is formed in the inner pipe section of a double pipe structure with a space insulation layer formed around it, so the insulation effect of the magnetocaloric material enclosed section is enhanced and cooling efficiency can be improved. Also, since the liquid heat transfer medium cooled by the chiller is sent to the magnetocaloric material enclosed section, the time required for the magnetocaloric material to be cooled to a predetermined temperature is shortened and the magnetocaloric effect can be effectively exerted. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is an explanatory diagram showing the overall configuration of a magnetic refrigeration device according to a first embodiment. [Figure 2] FIG. 2 is an explanatory diagram showing the configuration of a chiller. [Figure 3] FIG. 2 is an explanatory diagram (cross-sectional view) showing the double-pipe structure of the magnetic refrigeration unit. [Figure 4] FIG. 1 is an explanatory diagram (cross-sectional view) showing a configuration example (1) of a double-pipe structure. [Figure 5] FIG. 10 is an explanatory diagram (cross-sectional view) showing a configuration example (2) of a double-pipe structure. [Figure 6] FIG. 10 is an explanatory diagram (cross-sectional view) showing a configuration example (3) of a double-pipe structure. [Figure 7] FIG. 1 is an explanatory diagram (cross-sectional view) showing an example of a bellows structure (1) at a bent portion of a closed flow path. [Figure 8] FIG. 10 is an explanatory diagram (cross-sectional view) showing an example of a bellows structure (2) at a bent portion of a closed flow path. [Figure 9] FIG. 10 is an explanatory diagram (cross-sectional view) showing an example of a bellows structure (3) at a bent portion of a closed flow path. [Figure 10] FIG. 2 is an explanatory diagram showing the positions of sensors in the magnetic refrigeration device. [Figure 11] FIG. 4 is an explanatory diagram showing the control timing of a flow regulation valve. [Figure 12] FIG. 2 is an explanatory diagram showing an example of the configuration of a flow rate control unit. [Figure 13] FIG. 2 is an explanatory diagram showing a control system of a magnetic refrigeration device. [Figure 14] FIG. 10 is an explanatory diagram showing the overall configuration of a magnetic refrigeration device according to a second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0012] 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.

[0013] (Embodiment 1) 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 the temperature of a magnetic material changes 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.

[0014] The main component of the magnetic refrigeration device 1 is a magnetic refrigeration unit 10. The magnetic refrigeration unit 10 includes a magnetocaloric material enclosure 11 in which the above-mentioned magnetocaloric material M is enclosed, and by utilizing the magnetocaloric effect, a temperature gradient is generated in which one end of the magnetocaloric material enclosure 11 is a low-temperature end and the other end is a high-temperature end.

[0015] That is, the magnetocaloric material M enclosed in the magnetocaloric material encapsulation section 11 is repeatedly magnetized (applied with a magnetic field) and demagnetized (removed from the magnetic field), and when the magnetocaloric material generates heat due to the excitation, the flow of the liquid heat medium is stopped, and when the magnetocaloric material M absorbs heat due to the demagnetization, the liquid heat medium in the magnetocaloric material encapsulation section 11 is moved to the low temperature end side.

[0016] In order to perform such operations, the magnetic refrigeration device 1 is equipped with a closed flow path 12 which is a heat medium circulation path through which the liquid heat medium circulates, including the inside of the magnetocaloric material enclosing portion 11, a chiller 2 which cools the liquid heat medium, a magnetic field generator 14 which magnetizes and demagnetizes the magnetocaloric material M, a flow regulating valve 4 which regulates the movement of the liquid heat medium into the magnetocaloric material enclosing portion 11, a flow rate control portion 3 which adjusts the flow rate of the liquid heat medium, and a control device 100 which controls the flow regulating valve 4 and the flow rate control portion 3 based on data acquired by various sensors. The liquid heat medium which flows through 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).

[0017] The chiller 2 has a built-in pump 2B, which will be described later, and the pump 2B causes the liquid heat transfer medium to flow in the direction of the arrow L1 in the closed flow path 12. In addition, a flow regulation valve 4 is provided downstream of the chiller 2 and near the inlet of the magnetocaloric material sealing part 11, which controls the passage / stop of the liquid heat transfer medium.

[0018] The magnetic field generator 14 may be a magnet rotary 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 magnetizes the magnetocaloric material M, the flow of the liquid heat medium is stopped by closing the flow regulating valve 4, and when the magnetic field generator 14 demagnetizes the magnetocaloric material M, the flow regulating valve 4 is opened so that only the cooled liquid heat medium flows to the low temperature end. The control of the flow regulating valve 4 will be described in detail later.

[0019] The magnetocaloric material enclosing part 11 is a tubular member enclosing a magnetocaloric material, and filters 11A and 11B through which the liquid heat transfer medium passes are provided at both ends of the tubular member. The filters 11A and 11B, together with the magnetocaloric material enclosing part 11, constitute the magnetic refrigeration unit 10.

[0020] The filter 11A is a deoxidizing filter that removes oxygen dissolved in the liquid heat medium, preventing oxidation of the magnetocaloric material M. The deoxidizing filter may be any filter that functions in an environment of -20°C, and examples include a method using a nitrogen-substituted hollow fiber membrane and a method using hydrogen plasma. The liquid heat medium that has passed through the flow regulating valve 4 passes through the filter 11A and is moved to the magnetocaloric material sealing part 11. The filter 11B is a filter for preventing the magnetocaloric material M from flowing out from the magnetocaloric material sealing portion 11, and is disposed at the delivery portion (low temperature end side) of the magnetocaloric material sealing portion 11.

[0021] The liquid heat transfer medium sent out from the low-temperature end of the magnetocaloric material confinement portion 11 passes through the flow rate control portion 3, and then exchanges heat (absorbs heat) with the object to be cooled Co. Then, it is returned to the chiller 2 through the return port 2P. Then, after being cooled in the chiller 2, it is discharged again from the discharge port 2Q into the magnetocaloric material confinement portion 11. All of these flows are carried out via the closed flow path 12.

[0022] As shown in Fig. 2, the chiller 2 circulates the liquid heat medium stored in the cooling tank 2A ​​through a closed flow path 12 using a pump 2B and returns it 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 aforementioned evaporator 20A, compressor 20B, condenser (heat radiator) 20C, and expansion valve 20D.

[0023] 3, the specific structure of the magnetic refrigeration unit 10 can be a double-pipe structure including an inner pipe portion 10A through which the above-mentioned liquid heat transfer medium 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 a vacuum insulation layer 10V to enhance the heat insulation effect.

[0024] Because the magnetic field generator (e.g., magnet) 14A of the magnetic field generator 14 is disposed outside the outer tube 10B, the material for the inner tube 10A must be nonmagnetic and low-permeability so as not to interfere with the magnetization and demagnetization of the magnetocaloric material M. Furthermore, to enhance the insulating effect of the vacuum insulation layer 10V formed by the inner tube 10A and the outer tube 10B, it is preferable to give the outer surface of the inner tube 10A a mirror finish. Considering these factors, austenitic (nonmagnetic) stainless steel (e.g., SUS304), aluminum, or copper are suitable materials for the inner tube 10A. To further enhance the insulating effect, it is even more preferable to use MLI (aluminum-deposited polyester film) on the outer surface of the inner tube 10A.

[0025] 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 thermal 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 (SUS304), etc. Furthermore, it is preferable to form the inner pipe portion 10A from a material with higher thermal conductivity than the material of the outer pipe portion 10B in order to improve the heat insulating effect of the magnetic refrigeration unit 10. Specifically, the inner pipe portion 10A is formed from aluminum, and the outer pipe portion 10B is formed from another material with lower thermal conductivity than aluminum.

[0026] When the magnetic refrigeration unit 10 has a double-pipe structure, it is preferable to make the distance between the inner pipe portion 10A and the outer pipe portion 10B as short as possible in order to efficiently magnetize and demagnetize the magnetocaloric material M sealed inside the inner pipe portion 10A. Because the distance between the inner pipe portion 10A and the outer pipe portion 10B is a space for forming the vacuum insulation layer 10V, it is preferable to make the distance as short as possible within a range that allows the vacuum insulation layer 10V to effectively maintain the low temperature generated in the magnetic refrigeration unit 10.

[0027] Furthermore, the double-pipe structure in which the magnetocaloric material enclosing part 11 is formed may itself be housed in a vacuum chamber to enhance thermal insulation. Note that it is sufficient that at least the magnetocaloric material enclosing part 11 is housed in the vacuum chamber, but the flow rate control part 3 and part of the piping to the object to be cooled Co may also be housed in addition to the magnetocaloric material enclosing part 11. Furthermore, when the magnetocaloric material enclosing part 11 is housed in a vacuum chamber, it is not necessary to use a double-pipe structure provided with the above-mentioned vacuum insulation layer 10V.

[0028] In the magnetic refrigeration unit 10, a temperature difference occurs at the boundary between the inner pipe portion 10A and the outer pipe portion 10B and at the boundary between the outer pipe portion 10B and the room (atmospheric side). If this temperature difference causes a difference in thermal expansion and contraction between the inner pipe portion 10A and the outer pipe portion 10B, it can lead to damage to the magnetic refrigeration device 1. Therefore, in the present invention, a bellows structure is provided in the double pipe structure of the magnetic refrigeration unit 10 to prevent such damage from occurring.

[0029] 4 shows a first example (1) of the double-pipe structure of the magnetic refrigeration unit 10. In the example shown, when connecting the end of the outer pipe part 10B to the inner pipe part 10A, a bellows structure B1 is added near the connecting end to disperse thermal stress generated by the temperature gradient of the magnetic refrigeration unit 10. Note that in order to improve the thermal insulation of the magnetocaloric material confinement part 11, the bellows structure B1 is preferably made of a thermally insulating material.

[0030] 5 shows a second configuration example (2) of the double-pipe structure of the magnetic refrigeration unit 10. In the illustrated example, when connecting the end of the inner pipe portion 10A to the closed flow path 12, a bellows structure B2 is added near the connecting end to disperse thermal stress generated by the temperature gradient of the magnetic refrigeration unit 10.

[0031] Furthermore, a disk-shaped support portion 13A that protrudes outward is provided near the closed flow path 12 to which the bellows structure B2 is connected. The support portion 13A is made of a material or shape that is robust against stress (for example, a thickness that provides sufficient strength). The support portion 13A is then connected to a bellows structure B3 that is provided near the connection end of the outer tube portion 10B. This structure disperses thermal stress generated by the temperature gradient in the magnetic refrigeration unit 10. At least one of the support portion 13A and the bellows structure B3 is preferably made of a heat-insulating material.

[0032] 6 shows a third configuration example (3) of the double-pipe structure of the magnetic refrigeration unit 10. In the illustrated example, when connecting the end of the inner pipe portion 10A to the closed flow path 12, a bellows structure B4 is added near the connection end to disperse thermal stress generated by the temperature gradient of the magnetic refrigeration unit 10. In addition, a disk-shaped support portion 13B that protrudes outward is provided near the closed flow path 12 to which the bellows structure B4 is connected, and this support portion 13B is directly connected to the outer pipe portion 10B. The support portion 13B is made of a heat-insulating material and is made of a material or shape that is robust against stress (for example, has a thickness that is sufficiently strong).

[0033] 4 to 6 show an example of a bellows structure that accommodates thermal expansion and contraction of the double pipe in the magnetic refrigeration unit 10, but as the liquid heat transfer medium flows, the pipes that make up the closed flow path 12 (which are equivalent to the inner pipe portion 10A) also expand and contract due to heat. In particular, thermal stress is concentrated at the bent portions of the piping. Therefore, in the present invention, the effects of this thermal stress are absorbed at or near the bent portions of the closed flow path 12. 7 shows an example of a bellows structure (1) at a bend in the closed flow path 12 of the magnetic refrigeration device 1. In the example shown, a bellows structure B5 is provided in the inner pipe portion 10A located at the bend, thereby dispersing thermal stress generated by temperature changes in the liquid heat transfer medium flowing inside the pipe.

[0034] 8 shows an example (2) of a bellows structure at a bent portion of the closed flow path 12 of the magnetic refrigeration device 1. In the example shown, two bellows structures B6 are provided at adjacent positions sandwiching one bent portion. The two bellows structures B6 are provided at the ends of the straight portions of the inner pipe portion 10A, respectively. Since it is only necessary to form a straight bellows structure B6, the workload can be reduced.

[0035] FIG. 9 shows a bellows structure example (3) at a bend in the closed flow path 12 of the magnetic refrigeration device 1. Structure example (3) provides a bellows structure B7 only at the end of a pipe having a piping length equal to or greater than a predetermined straight length. In the illustrated example, one bellows structure B7 is provided for each bend. However, if the piping length does not meet the predetermined length, no bellows structure B7 may be provided. The predetermined length is determined by the piping material, thickness, temperature of the liquid heat transfer medium, temperature change range, etc. In FIG. 9, only the piping length in the horizontal direction is equal to or greater than the predetermined length. On the other hand, the bellows structure B7 is not added to the piping in the vertical direction because the piping length is less than the predetermined length.

[0036] Furthermore, the bellows structure B7 is provided around half the circumference of the cylindrical piping, rather than the entire circumference. By providing an optimal bellows structure B7 that corresponds to the piping characteristics of the closed flow path 12 in this way, it is possible to reduce the workload and costs. It also allows for greater flexibility in the placement of various structures and piping in the magnetic refrigeration device 1, where various structures are arranged in a complex manner. In the illustrated example, the bellows structure B7 is provided on the outer periphery of the piping (the lower side in the figure), but the position at which the bellows structure B7 is formed is not limited to this. It may be on the inner periphery of the piping (the upper side in the figure), on a side, or in any other position. The bellows structure B7 may be formed around less than or more than half the circumference, as long as it can accommodate thermal expansion and contraction of the piping.

[0037] Furthermore, among the bent portions of the closed flow path 12, the inner pipe portion 10A is cooled most near the output portion of the magnetic refrigeration unit 10, and the inner pipe portion 10A is heated most near the output portion of the object to be cooled Co. Therefore, it is preferable to make the length of the bellows structure provided at these bent portions of the closed flow path 12 longer than at other portions.

[0038] As shown in Fig. 10, by equipping each part with sensors, the magnetic refrigeration device 1 can appropriately control the operation of the parts to be controlled while monitoring the operating status. In Fig. 10, 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.

[0039] The temperature sensor S2 is installed between the magnetic refrigeration unit 10 and the flow rate control unit 3 in the closed flow path 12, 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 state of the magnetic refrigeration device 1 can be grasped.

[0040] The flow rate sensor S3 is installed upstream of the object to be cooled Co in the closed flow path 12 and detects the flow rate of the liquid heat transfer medium sent to the object to be cooled Co. The flow rate control unit 3, which is installed upstream of the flow rate sensor S3, controls the flow rate of the liquid heat transfer medium sent to the object to be cooled Co based on the flow rate detected by the flow rate sensor S3.

[0041] Temperature sensor S4 detects the temperature of the liquid heat medium exiting cooling tank 2A ​​of chiller 2. Because the liquid heat medium cooled by chiller 2 is used in magnetic refrigeration unit 10, the time required for magnetocaloric material M to be cooled to a predetermined temperature can be shortened, enabling the magnetocaloric effect to be effectively exerted. Therefore, the temperature of the liquid heat medium output from chiller 2 is appropriately controlled based on the measurement value of temperature sensor S4. The temperature of cooling tank 2A ​​can be adjusted by controlling compressor 20B of refrigerant circuit 20.

[0042] The magnetic sensor S5 detects the magnetized or demagnetized state of the magnetocaloric material in the magnetocaloric material enclosure 11. In order for the magnetic sensor S5 to detect the timing of demagnetization (heat absorption) of the magnetocaloric material M, it is necessary to capture with high sensitivity and in real time the moment when the magnetocaloric material M transitions from a magnetized state to a non-magnetized state. Suitable magnetic sensors S5 for this purpose include a magnetoresistive sensor (MR sensor), a Hall sensor, and a fluxgate sensor.

[0043] The temperature sensor S6 detects the temperature inside the magnetocaloric material sealing portion 11. The temperature sensor S6 detects that the magnetocaloric material M inside the magnetocaloric material sealing portion 11 has transitioned to a heat absorption process due to demagnetization.

[0044] Next, a method for controlling the flow regulating valve 4 will be described with reference to FIG. While the magnetic refrigeration unit 10 is magnetized, the temperature of the object to be cooled Co (detected by temperature sensor S1) gradually rises. When the temperature detected by temperature sensor S1 exceeds a preset threshold temperature T1, the magnetic refrigeration unit 10 transitions to the demagnetization process. The transition to the demagnetization process is detected by magnetic sensor S5. Furthermore, the transition of the magnetocaloric material M to the heat absorption process is detected by temperature sensor S6. Then, when the transition to the demagnetization process and the heat absorption process is detected, the flow regulating valve 4 is opened, and the cooled liquid heat medium from the chiller 2 is sent to the magnetic refrigeration unit 10 and output to the object to be cooled Co.

[0045] The temperature of the liquid heat medium output to the object to be cooled Co can be made lower than the temperature of the liquid heat medium sent out from the chiller 2 due to the cooling effects of both the chiller 2 and the magnetic refrigeration unit 10 .

[0046] When the object Co is sufficiently cooled and the temperature sensor S1 confirms that the temperature of the object Co has fallen below a preset threshold temperature T2, the magnetic refrigeration unit transitions to the excitation process. After that, the flow control valve 4 is closed through a process similar to that after transition to the demagnetization process described above. Thereafter, this process of switching the open / closed state of the flow control valve 4 is repeated.

[0047] In this way, by automatically controlling the flow regulating valve 4 using the detection values ​​of each sensor, it is possible to automatically control the liquid heat transfer medium to flow to the low temperature end only when the magnetocaloric material M is demagnetized (when absorbing heat). In addition, by adjusting the detection certification conditions and threshold values, it is possible to perform detailed automatic control in accordance with the object to be cooled Co.

[0048] In the above example, the flow restriction valve 4 is opened after detecting that the process has shifted to the demagnetization process and that the process has shifted to the heat absorption process, but the flow restriction valve 4 may be opened after confirming either one of these. All of these controls are controlled by the control device 100.

[0049] Next, the flow rate control unit 3 will be described. The flow rate control unit 3 is provided in the closed flow path 12 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 the faster the flow rate of the liquid heat medium flowing through the closed flow path 12, the higher the cooling efficiency of the object to be cooled Co. The basic flow rate of the circulation flow rate through the closed flow path 12 is determined by the pump capacity of the chiller 2, but by increasing the flow rate of the liquid heat medium with the flow rate control unit 3, the cooled liquid heat medium can be efficiently supplied to the object to be cooled Co.

[0050] As shown in Fig. 12, 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 closed flow path 12, the flow rate on the downstream side thereof can be increased. As shown in the figure, 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.

[0051] 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 closed flow path 12, 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 cooling object Co.

[0052] For example, a Venturi tube structure 3A is provided as the first-stage flow rate control unit 3 on the upstream side of the magnetic refrigeration unit 10 and adjusted to a flow rate of 70% of the target inflow rate to the cooling object Co, and an orifice structure 3B is provided as the second-stage flow rate control unit 3 on the upstream side of the cooling object Co (between the magnetic refrigeration unit 10) to adjust the flow rate of the liquid heat medium to the target inflow rate to the cooling object Co.

[0053] When the liquid heat medium passes through the magnetic heat material encapsulation part 11 in which the magnetic heat material M is encapsulated, variations occur in the flow rate of the liquid heat medium. However, based on the flow rate detected by the flow rate sensor S3, by automatically controlling the opening diameter (i.e., the flow path cross-sectional area) of the shutter member 3S of the orifice structure 3B, it becomes possible to adjust to the accurate target inflow rate.

[0054] The control system of the magnetic refrigeration device 1 will be described with reference to Figure 13. The magnetic refrigeration device 1 performs operational control based on the detection values ​​of the above-mentioned sensors, thereby improving start-up characteristics, cooling efficiency, and cooling capacity. Here, central management control by the control device 100 will be described. The control device 100 is a so-called computer, and includes, as basic elements, a processor 101, a memory 102, an input unit 103, and an output unit 104, which are connected to each other via a bus 110 so as to be able to communicate with each other.

[0055] 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.

[0056] The various sensors that input detection results to the input unit 103 are shown in Figure 10 and include a temperature sensor S1 that detects the temperature of the object to be cooled Co, a temperature sensor S2 that detects the temperature of the liquid heat medium sent to the object to be cooled Co, a flow rate sensor S3 that detects the flow rate of the liquid heat medium sent to the object to be cooled Co, a temperature sensor S4 that detects the temperature of the liquid heat medium coming out of the chiller 2, a magnetic sensor S5 that detects the magnetized / demagnetized state of the magnetocaloric material M in the magnetocaloric material sealing portion 11, and a temperature sensor S6 that detects the temperature inside the magnetocaloric material sealing portion 11.

[0057] On the other hand, the control targets of the magnetic refrigeration apparatus 1, to which the output unit 104 outputs a control signal, are the magnetic field generator 14, the chiller 2 (compressor 20B), the flow rate control unit 3, the flow regulation valve 4, and the like.

[0058] 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 to be sent to the magnetocaloric material enclosing part 11 through the closed flow path 12 to an appropriate temperature. As an example, when a material that is effective in a low-temperature environment is selected as the magnetocaloric material M, the liquid heat medium coming out of the chiller 2 is cooled to about -20°C.

[0059] Then, the control device 100 (processor 101) operates the magnetic refrigeration device 1 in a steady state. At that time, the control device 100 (processor 101) synchronously drives the flow regulating valve 4 and the magnetic field generator 14, and opens the flow regulating valve 4 only at the timing of demagnetizing the magnetocaloric material M, causing the liquid heat medium to move to the magnetocaloric material sealing portion 11. During this control, by using the detection values ​​of the magnetic sensor S5 and the temperature sensor S6, it is possible to reliably move the liquid heat medium to the magnetocaloric material sealing portion 11 at the timing of transition to the demagnetization / heat absorption process, thereby shortening the time required for the magnetocaloric effect to occur.

[0060] In addition, when cooling the liquid heat transfer medium sent to the object to be cooled Co through the closed flow path 12, the control device 100 (processor 101) can appropriately improve the cooling efficiency and cooling capacity by combining the cooling by the chiller 2 and the cooling by the magnetocaloric effect by the magnetic refrigeration unit 10 with flow rate control by the flow rate control unit 3.

[0061] Specifically, when the target cooling temperature is relatively high, in order to reduce energy consumption and improve cooling efficiency, cooling by the magnetocaloric effect, which has a high energy load, is suppressed and the proportion of cooling by chiller 2 is increased, thereby improving cooling efficiency. On the other hand, when the target cooling temperature is extremely low, cooling by chiller 2 and cooling by the magnetocaloric effect are fully utilized to increase cooling capacity, while flow rate control is effectively employed to improve cooling efficiency.

[0062] (Embodiment 2) In the first embodiment, a configuration was shown in which the liquid heat transfer medium cooled in the magnetocaloric material enclosing section 11 is sent to the object to be cooled Co through the closed flow path 12, but the second embodiment differs from the first embodiment in that the liquid heat transfer medium cooled by heat exchange with the working fluid cooled in the magnetocaloric material enclosing section 11 is sent to the object to be cooled Co. In the magnetic refrigeration apparatus 201 according to the second embodiment, as shown in FIG. 14, a magnetic refrigeration unit 210 includes a low-temperature side heat exchanger 232 in addition to the magnetocaloric material enclosing portion 11, a filter 11A, and a filter 11B.

[0063] The magnetic refrigeration device 201 is also provided with a flow direction changer 230, and a working fluid flow path 238, which is a closed flow path through which working fluid can circulate in both directions, is formed between the magnetic refrigeration unit 210 and the flow direction changer 230. The working fluid in the second embodiment refers to a medium that flows inside the magnetocaloric material enclosing portion 11, and a liquid with a large heat capacity and high thermal conductivity (for example, water or an ethylene glycol aqueous solution) is used.

[0064] A piston pump, a double piston pump, a diaphragm pump, etc. can be used as the flow direction changer 230. The flow direction changer 230 causes the working fluid flowing through the magnetocaloric material enclosing portion 11 and the working fluid flow path 238 to move back and forth as shown by the arrow L2 in the figure.

[0065] The flow direction changer 230 is controlled in synchronization with the operation of the magnetic field generator 14. That is, at the timing when the magnetic field generator 14 magnetizes the magnetocaloric material M, the flow direction changer 230 switches the flow of the working fluid from the low-temperature side heat exchanger 232 side to the high-temperature side heat exchanger 234 side (counterclockwise in the figure), and at the timing when the magnetic field generator 14 demagnetizes the magnetocaloric material M, the flow direction changer 230 switches the flow of the working fluid from the high-temperature side heat exchanger 234 side to the low-temperature side heat exchanger 232 side (clockwise in the figure).

[0066] By controlling the flow direction changer 230 and the magnetic field generator 14 in this manner in synchronization, low-temperature working fluid flows to the low-temperature side heat exchanger 232 and high-temperature working fluid flows to the high-temperature side heat exchanger 234.

[0067] The liquid heat medium circulating through the closed flow path 12 exchanges heat with the low-temperature working fluid in the low-temperature side heat exchanger 232, where it is cooled, and is then sent to the object to be cooled Co. The liquid heat medium, whose temperature has risen in the object to be cooled Co, passes through the closed flow path 12, is cooled in the chiller 2, and is then further cooled again by heat exchange with the low-temperature side heat exchanger 232, and is then sent to the object to be cooled Co. This circulation is repeated. Meanwhile, the high-temperature side heat exchanger 234 cools the working fluid moving through the working fluid flow path 238 by dissipating heat using a well-known method. By using such embodiment 2, it is possible to efficiently cool the object to be cooled Co.

[0068] Also in the second embodiment, similarly to the first embodiment, by forming a vacuum insulating layer 10V around the magnetocaloric material sealing portion 11, it is possible to improve the insulating effect.

[0069] Furthermore, by forming a bellows structure in the vacuum insulation layer 10V, it is possible to protect the magnetic refrigeration device 201 from thermal stress and thermal distortion of the piping, etc., as in the first embodiment. For the same reason, it is also effective to provide a bellows structure at or adjacent to a bent portion of the closed flow path 12 through which the liquid heat transfer medium flows or the working fluid flow path 238 through which the working fluid flows.

[0070] In this second embodiment, a configuration has been described that includes two flow paths, a closed flow path 12 through which the liquid heat transfer medium flows and a working fluid flow path 238 through which the working fluid moves back and forth. However, the same effect can be achieved by applying the configuration of the present invention, such as a double-pipe structure or a chiller 2, to a configuration in which the liquid heat transfer medium sent to the object to be cooled Co moves back and forth in both directions within the magnetocaloric material enclosed section 11 (for example, the configuration of Figure 2 of Patent Document 1).

[0071] The features of the magnetic refrigeration device 1 can be summarized as follows. The magnetic refrigeration device 1 comprises a magnetic refrigeration unit 10 having a magnetic calorific material containing section 11 in which an inner pipe section 10A of a double pipe structure around which a vacuum insulation layer 10V is formed, and a closed flow path 12 that supplies the liquid heat medium cooled by the magnetic refrigeration unit 10 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.

[0072] According to this, the magnetocaloric material confinement section 11 is provided with an inner pipe section 10A of a double pipe structure surrounded by a vacuum insulation layer 10V, which enhances the heat insulating effect of the magnetocaloric material confinement section 11 and makes it possible to improve the cooling efficiency. Also, a chiller is provided on the closed flow path 12, and the liquid heat medium cooled by the chiller is sent to the magnetic refrigeration unit 10, thereby shortening the time required for the magnetocaloric effect to be exhibited.

[0073] The magnetic refrigeration apparatus 1 has an inner pipe portion 10A with a higher thermal conductivity than the outer pipe portion 10B of the double pipe structure, which allows the heat insulating effect of the magnetic refrigeration apparatus 1 to be improved.

[0074] In the magnetic refrigeration device 1, at least one of the outer pipe portion 10B and the inner pipe portion 10A of the double pipe structure is joined to the other via a bellows structure. In addition, a bellows structure is provided at or adjacent to a bent portion of the closed flow path 12 and / or the working fluid flow path 238. This allows for the expansion and contraction of the pipes that accompany temperature changes due to the magnetic refrigeration effect, and protects the magnetic refrigeration device 1 from damage due to thermal stress and thermal distortion.

[0075] The magnetic refrigeration device 1 is provided with one or more flow rate control units 3 that increase the flow rate by narrowing the cross-sectional area of ​​the flow path, thereby effectively improving the cooling efficiency and cooling capacity by controlling the flow rate of the liquid heat transfer medium.

[0076] The magnetic refrigeration device 1 is provided with a flow velocity control section 3 having a venturi structure, an orifice structure, or a combination thereof. This allows the flow velocity control section 3 to be configured to be suitable for the magnetic refrigeration device 1.

[0077] The magnetic refrigeration device 1 is equipped with a flow rate control unit 3 that detects the flow rate and can variably control the flow path cross-sectional area in response to an external signal. This makes it possible to control the flow rate to a value suitable for the object Co to be cooled.

[0078] The magnetic refrigeration device 1 is provided with a chiller 2 on a closed flow path 12 that cools the liquid heat transfer medium that has undergone heat exchange with the object to be cooled Co and returns it to the magnetic refrigeration unit 10, and is also provided with flow rate control units 3 both upstream of the object to be cooled Co and upstream of the magnetic refrigeration unit 10.

[0079] By arranging the chiller 2 in this manner, it is possible to lower the temperature of the liquid heat medium sent to the magnetic refrigeration unit 10, thereby shortening the time during which the magnetocaloric effect is exerted. In addition, by configuring the flow rate control unit 3 in multiple stages, it is possible to appropriately adjust the flow rate of the liquid heat medium so that the temperature quickly converges to the target cooling temperature for the object Co to be cooled.

[0080] The magnetic refrigeration device 1 has a magnetocaloric material enclosing section 11 disposed in a vacuum chamber surrounding the double-pipe structure. This allows a high thermal insulation effect to be obtained by the vacuum chamber in addition to the vacuum insulation layer 10V of the double-pipe structure.

[0081] The magnetic refrigeration device 1 is equipped with a flow restriction valve 4 that restricts the timing of the flow of the liquid heat transfer medium passing through the magnetocaloric material confinement portion 11, and the flow restriction valve 4 allows the flow of the liquid heat transfer medium based on one or both of the detection of a demagnetized state and the detection of transition to a heat absorption process in the magnetocaloric material confinement portion 11. This allows the flow restriction valve 4 to be automatically controlled based on the detection values ​​of each sensor, allowing the magnetic refrigeration device 1 to operate automatically. Moreover, because the control is based on the detection values ​​of each sensor, it is possible to perform objective and finely adjustable operation.

[0082] 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]

[0083] 1,201: Magnetic refrigeration equipment 2: Chiller 2A: Cooling tank 2B: Pump 2P: Return port 2Q: Discharge port 3: Flow velocity control section 3A: Venturi tube structure 3B: Orifice structure 3S: Shutter member 4: Flow control valve 10, 210: Magnetic refrigeration unit 10A: Inner pipe part 10B: Outer pipe part 10V: Vacuum insulation layer 11: Magnetocaloric material sealing portion 11A, 11B: Filter 12: Closed flow path 13A, 13B: Supporting portion 14: Magnetic field generating device 14A: Magnetic field generator 20: Refrigerant circuit 20A: Evaporator 20B: Compressor 20C: Condenser 20D: Expansion valve 100: Control device 101: Processor 102: Memory 103: Input section 104: Output section 110: Bus 230: Flow direction changer 232: Low temperature side heat exchanger 234: High temperature side heat exchanger 238: Hydraulic fluid flow path S1, S2, S4, S6: Temperature sensors S3: Flow rate sensor S5: Magnetic sensor T1, T2: Threshold temperature Co: cooling object M: magnetocaloric material B1, B2, B3, B4, B5, B6, B7: Bellows structure

Claims

1. A magnetic refrigeration device that cools an object using the magnetocaloric effect, a magnetic refrigeration unit including a magnetocaloric material enclosed portion; and a heat medium circulation flow path that supplies a liquid heat medium cooled by the magnetic refrigeration unit to an object to be cooled and returns the liquid heat medium that has exchanged heat with the object to be cooled to a chiller, The magnetocaloric material confinement portion is formed in an inner pipe portion of a double pipe structure having a space heat insulating layer formed around it, At least one of the outer pipe portion and the inner pipe portion of the double pipe structure is joined to the other via a bellows structure. Magnetic refrigeration equipment.

2. The liquid heat transfer medium in the heat transfer medium circulation flow path is Cooled by the magnetocaloric material enclosure, Alternatively, the magnetocaloric material is cooled by a low-temperature side heat exchanger provided at the low-temperature end formed by the working fluid reciprocating through the magnetocaloric material enclosed portion.

2. The magnetic refrigeration system according to claim 1.

3. The inner pipe portion is formed of a material having a higher thermal conductivity than the outer pipe portion of the double pipe structure. The magnetic refrigeration device according to claim 1 .

4. a bellows structure is provided at or adjacent to a bent portion in the heat transfer medium circulation flow path; 2. The magnetic refrigeration device according to claim 1.

5. A bellows structure is provided in the flow path through which the hydraulic fluid flows at or adjacent to the bent portion.

3. The magnetic refrigeration device according to claim 2.

6. The heat medium circulation flow path is provided with one or more flow rate control units that increase the flow rate by narrowing the cross-sectional area of ​​the flow path.

2. The magnetic refrigeration device according to claim 1.

7. The flow rate control section has one or a combination of a venturi structure and an orifice structure.

7. The magnetic refrigeration device according to claim 6.

8. The flow rate control unit detects a flow rate and variably controls the flow path cross-sectional area in response to an external signal.

7. The magnetic refrigeration device according to claim 6.

9. the chiller disposed in the heat medium circulation flow path cools the liquid heat medium that has undergone heat exchange with the object to be cooled and returns the liquid heat medium to the magnetic refrigeration unit; the flow rate control unit is provided on both the upstream side of the object to be cooled and the upstream side of the magnetic refrigeration unit; 7. The magnetic refrigeration device according to claim 6.

10. The magnetocaloric material confinement section is disposed in a vacuum chamber surrounding the double-tube structure.

2. The magnetic refrigeration device according to claim 1.

11. the magnetic refrigeration device includes a flow regulation valve that regulates the timing of flow of the liquid heat transfer medium passing through the magnetocaloric material enclosing portion, the flow regulating valve allows the liquid heat transfer medium to flow based on one or both of detection of a demagnetized state and detection of transition to a heat absorption process in the magnetocaloric material enclosing portion; 2. The magnetic refrigeration device according to claim 1.

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