JP2020008247A - Magneto-caloric element and thermomagnetic cycle device - Google Patents

Abstract

To provide a magneto-caloric element that can improve heat exchange efficiency, and to provide a thermomagnetic cycle device using the same.SOLUTION: A magneto-caloric element includes: a plurality of particles 81 made of a magneto-caloric effect material providing magneto-caloric effect; and a binder 82 for agglomerating and holding the particles. The magneto-caloric element is formed with a medium flow passage 1211 through which a heat transport medium can circulate. At a surface facing the medium flow passage 1211, the particle 81 has an exposure area that is larger than an exposure area of the binder 82.SELECTED DRAWING: Figure 5

Description

  The technology disclosed herein relates to a magnetocaloric element and a thermomagnetic cycle device using the magnetocaloric element.

  2. Description of the Related Art Conventionally, a thermomagnetic cycle device utilizing a magnetocaloric effect has been known. Such a device uses a magnetocaloric element in which a plurality of particles made of a magnetocaloric material exhibiting a magnetocaloric effect are aggregated and held by a resin binder. An apparatus using such an element is disclosed in, for example, Patent Document 1 below.

JP 2017-26305 A

  However, in the above-described conventional magnetocaloric element, a skin layer is generally formed on the element surface by a material constituting a binder at the time of molding. The skin layer made of the binder material has a problem that the heat exchange between the magnetocaloric element and the heat transport medium causes a large thermal resistance, thereby lowering the heat exchange efficiency.

  The technology disclosed herein has been made in view of the above points, and has as its object to provide a magnetocaloric element capable of improving heat exchange efficiency and a thermomagnetic cycle device using the same.

In order to achieve the above object, in the disclosed magnetocaloric element,
A plurality of particles (81) of a magnetocaloric material exhibiting a magnetocaloric effect;
A binder (82) for aggregating and holding a plurality of particles,
A magnetocaloric element in which a medium flow path (1211) through which a heat transport medium can flow is formed,
On the surface facing the medium flow path, the exposed area of the particles is larger than the exposed area of the binder.

  According to this, the particles made of the magnetocaloric effect material are exposed on the surface facing the medium flow path, and the exposed area of the particles is larger than the exposed area of the binder. Therefore, the thermal resistance on the surface facing the medium flow path can be reduced. Thus, the heat exchange efficiency between the magnetocaloric element and the heat transport medium can be improved.

  It should be noted that the reference numerals in parentheses described in the claims and this section indicate a correspondence relationship with specific means described in the embodiment described below as one aspect, and limit the scope of the disclosed technology. Not something.

It is a block diagram of a thermal appliance concerning a 1st embodiment. FIG. 2 is a sectional view taken along line II-II of FIG. 1. It is a perspective view showing a container containing a magnetocaloric element of a 1st embodiment. It is sectional drawing of the element plate which is a part of magneto-caloric element of 1st Embodiment. FIG. 5 is an enlarged view of a portion V in FIG. 4. 3 is a flowchart illustrating a manufacturing process of the magnetocaloric device according to the first embodiment. It is a model figure of a part of magnetocaloric element of a 1st embodiment. It is a model figure of a part of magnetocaloric element of a comparative example. It is sectional drawing of the element plate which is a part of magnetocaloric element of another embodiment. It is sectional drawing of the element plate which is a part of magnetocaloric element of another embodiment. It is a top view of an element plate which is a part of magnetocaloric element of other embodiments. It is sectional drawing of the element plate which is a part of magnetocaloric element of another embodiment. It is sectional drawing of the element plate which is a part of magnetocaloric element of another embodiment.

  Hereinafter, a plurality of modes for carrying out the disclosed technology will be described with reference to the drawings. In each embodiment, portions corresponding to the items described in the preceding embodiment are denoted by the same reference numerals, and redundant description may be omitted. When only a part of the configuration is described in each embodiment, the other parts of the configuration are the same as in the previously described embodiment. Not only the combinations of the parts specifically described in the respective embodiments but also the embodiments can be partially combined with each other as long as the combination is not particularly hindered.

(1st Embodiment)
A first embodiment to which the disclosed technology is applied will be described with reference to FIGS. FIG. 1 is a block diagram showing a vehicle air conditioner 1 to which the disclosed technology is applied. As shown in FIG. 1, the vehicle air conditioner 1 includes a magnetocaloric effect type heat pump device 10. The magnetocaloric effect heat pump device 10 is also called an MHP (Magneto-caloric effect Heat Pump) device 10. The MHP device 10 is also called a magnetic heat pump device 10. The MHP device 10 provides a thermomagnetic cycle device.

  In this specification, the term heat pump device is used in a broad sense. That is, the term “heat pump device” includes both a device using cold heat obtained by the heat pump device and a device using warm heat obtained by the heat pump device. An apparatus utilizing cold heat is sometimes called a refrigeration cycle apparatus. Therefore, in this specification, the term heat pump device is used as a concept including a refrigeration cycle device.

  The MHP device 10 includes a magnetocaloric element 12. The magnetocaloric element 12 is made of a magnetic work material having a magnetocaloric effect, and is also called an MCE (Magneto-CaloricEffect) element 12. Hereinafter, the magnetocaloric element 12 may be referred to as an MCE element 12 or a magnetic work material 12.

  The MHP device 10 includes a container 21 in which a working chamber 11 is formed. The container 21 is disposed in the housing 20 and defines at least one working chamber 11. In the present embodiment, the cylindrical container 21 defines a plurality of working chambers 11 arranged at equal intervals. In this example, one container 21 partitions and defines six working chambers 11, and each of the six working chambers 11 is filled with the MCE element 12. The container 21 may be called an element bed or a material bed. The container 21 is formed of a nonmagnetic material, for example, a resin.

  The MCE element 12 generates heat and absorbs heat depending on the strength of the external magnetic field. The MCE element 12 generates heat when an external magnetic field is applied, and absorbs heat when the external magnetic field is removed. In the MCE element 12, when the external magnetic field is applied and the electron spins are aligned in the magnetic field direction, the magnetic entropy decreases and the temperature rises by releasing heat. Further, in the MCE element 12, when the electron spin is disordered due to the removal of the external magnetic field, the magnetic entropy increases, and the temperature decreases by absorbing heat. The MCE element 12 is made of a magnetic material exhibiting a high magnetocaloric effect in a normal temperature range.

  The MCE element 12 includes a plurality of particles of a magnetic material and a binder that aggregates and holds the plurality of particles. As the particles of the magnetic substance, for example, particles of a lanthanum-iron-silicon compound can be used. Instead of part or all of silicon of the compound, one or more of manganese, iron, phosphorus, and germanium can be mixed and used. For the binder, for example, an epoxy resin can be used. The materials of the particles and the binder are not limited to those described above. The magnetic body may be, for example, a gadolinium-based material. The binder may be a thermosetting resin other than the epoxy resin. Further, it may be a thermoplastic resin. As the binder, for example, a material containing at least one of an epoxy resin, a melamine resin, a phenol resin, a fluorine resin, a polyethylene resin, and a polypropylene resin can be adopted. The configuration of the MCE element 12 will be described later in detail.

  The group of MCE elements 12 has a plurality of portions arranged along the longitudinal direction of the MCE elements 12, that is, along the flow direction of the primary medium. The plurality of parts are a plurality of element blocks described later. The material constituting each of the plurality of portions has a different Curie temperature. The plurality of portions exhibit a high magnetocaloric effect (ΔS (J / kgK)) in different temperature zones. The portion near the high-temperature end has a material composition that exhibits a high magnetocaloric effect near the temperature that appears at the high-temperature end in a steady operation state. The portion close to the middle temperature portion has a material composition that exhibits a high magnetocaloric effect near the temperature that appears in the middle temperature portion in a steady operation state. The portion near the low-temperature end has a material composition that exhibits a high magnetocaloric effect near the temperature that appears at the low-temperature end in a steady operation state.

  The temperature zone in which each part of the MCE element 12 exhibits a high magnetocaloric effect is called a high efficiency temperature zone. The upper limit temperature and the lower limit temperature of the high efficiency temperature zone depend on the material composition of the MCE element 12 and the like. The plurality of portions are arranged in series such that high-efficiency temperature zones are arranged between the high-temperature end and the low-temperature end. In other words, the high-efficiency temperature zones of the plurality of portions exhibit a distribution that gradually decreases from the high-temperature end between the high-temperature end and the low-temperature end. The distribution of the high efficiency temperature zone substantially corresponds to the temperature distribution between the high temperature end and the low temperature end in the steady state.

  In this embodiment, a plurality of portions share a steady-state temperature difference created between the high-temperature end and the low-temperature end in the steady operation. Thereby, high efficiency is obtained in each part. In other words, the MCE elements 12 are adjusted such that each element block exhibits a magnetocaloric effect exceeding a predetermined threshold when a steady temperature difference is obtained. The plurality of element blocks are arranged in a so-called cascade in the work room 11.

  The MHP device 10 utilizes the magnetocaloric effect of the MCE element 12. The MHP device 10 includes a magnetic field modulation device 13 and a heat transport device 14 for causing the MCE element 12 to function as an AMR (Active Magnetic Refrigeration) cycle.

  The magnetic field modulator 13 applies an external magnetic field to the MCE element 12 and increases or decreases the strength of the external magnetic field. The magnetic field modulator 13 periodically switches between an excited state in which the MCE element 12 is placed in a strong magnetic field and a demagnetized state in which the MCE element 12 is placed in a weak magnetic field or a zero magnetic field. The magnetic field modulator 13 modulates the external magnetic field such that the excitation period in which the MCE element 12 is placed in a strong external magnetic field and the demagnetization period in which the MCE element 12 is placed in an external magnetic field weaker than the excitation period are periodically repeated. I do. The magnetic field modulation device 13 includes a magnetic force source for generating an external magnetic field, for example, a permanent magnet or an electromagnet. In this example, the magnetic force source is a permanent magnet.

  The heat transport device 14 includes a fluid device for flowing a heat transport medium for transporting heat that the MCE element 12 releases or absorbs heat. The heat transport device 14 is a device that causes a heat transport medium that exchanges heat with the MCE element 12 to flow along the MCE element 12. The heat transport device 14 flows the heat transport medium so as to generate a high temperature end and a low temperature end in the MCE element 12. The heat transport device 14 generates the reciprocating flows FM and FN of the heat transport medium in synchronization with the change of the external magnetic field by the magnetic field modulator 13. Hereinafter, the flow FM from one end to the other end of the MCE element 12 may be referred to as an outward flow, and the flow FN from the other end to one end may be referred to as a return flow. In this example, the outward flow FM is a heat transport medium flow from the high-temperature end 11E1 to the low-temperature end 11E2. The return flow FN is a heat transport medium flow from the low temperature end 11E2 to the high temperature end 11E1. Hereinafter, the high temperature end 11E1 may be referred to as an end 11E1. Further, the low temperature end 11E2 may be referred to as an end 11E2.

  In this embodiment, the heat transport medium that exchanges heat with the MCE element 12 is called a primary medium. The primary medium can be provided by a fluid such as antifreeze, water, oil, and the like. The heat transport device 14 reciprocates the heat transport medium in synchronization with the increase and decrease of the magnetic field by the magnetic field modulator 13. The heat transport device 14 can include a pump for flowing the heat transport medium. The heat transport device 14 includes pumps 62 and 72 for flowing the primary medium. The heat transport device 14 includes a suction valve 111 and a discharge valve 112 provided at both ends of each working chamber 11. The pumps 62 and 72 cooperate with the suction valve 111 and the discharge valve 112 to supply a reciprocating flow of the primary medium to one MCE element 12 filled in each of the working chambers 11. One MCE element 12 is provided by combining a plurality of element blocks.

  The MHP device 10 includes a motor 15 as a power source. The motor 15 is a power source of the magnetic field modulator 13. The motor 15 is a power source of the heat transport device 14. The motor 15 provided as a power source of the MHP device 10 is driven by, for example, a vehicle-mounted battery. Further, the motor 15 rotationally drives a rotor core 31 that provides the magnetic field modulation device 13. As a result, the motor 15 and the magnetic field modulation device 13 cause periodic switching between a state where an external magnetic field is applied to the MCE element 12 and a state where the external magnetic field is removed from the MCE element 12. The motor 15 drives the pumps 62 and 72 of the heat transport device 14. Thus, the motor 15 and the pumps 62 and 72 cause a reciprocating flow of the primary medium in one MCE element 12. The MHP device 10 includes a transmission mechanism 18 on the output shaft of the motor 15 so that the increase and decrease of the magnetic field by the magnetic field modulation device 13 and the reciprocal movement of the heat transport medium by the heat transport device 14 are synchronized.

  The pumps 62 and 72 generate a reciprocating flow FM and FN of the primary medium in the working chamber 11 so that the MCE element 12 functions as an AMR cycle. The pumps 62 and 72 are, for example, positive displacement pumps. The pumps 62 and 72 are, for example, piston pumps. The pumps 62 and 72 are, for example, multi-cylinder radial piston pumps. One cylinder of the pump 62 and one cylinder of the pump 72 are associated with one MCE element 12. The two cylinders associated with one MCE element 12 operate synchronously. The functions of the pumps 62 and 72, the suction valve 111 and the discharge valve 112 provide reciprocating flows FM and FN of the primary medium flowing along the longitudinal direction of one MCE element 12. In this embodiment, the MHP device 10 includes a plurality of MCE elements 12 that are thermally connected in parallel. The MHP device 10 of this example has six MCE elements 12 that are thermally connected in parallel. The pumps 62 and 72 are six cylinders.

  The housing 20 is an outer cylindrical housing having a cylindrical portion and an end plate portion. The housing 20 rotatably supports the rotation shaft 22 on its central axis. The rotation shaft 22 is connected to an output shaft of the motor 15. The housing 20 accommodates the magnetic field modulator 13 around the rotation shaft 22. As shown in FIG. 2, the magnetic field modulation device 13 includes a rotor core 31, a yoke 32, a bearing 33, and magnets 34 and 35.

  The rotor core 31 is fixed to the rotating shaft 22. The rotor core 31 provides an inner yoke for the magnetic field modulator 13. The rotor core 31 is configured to form a range along which the magnetic flux can easily pass and a range where the magnetic flux does not easily pass along the circumferential direction. The rotor core 31 includes, for example, a pair of members having a fan-shaped cross section. A magnet 34 is fixed to the rotor core 31. The magnet 34 is partially cylindrical and has a fan-shaped cross section. The magnet 34 is fixed to the outer peripheral surface of the rotor core 31.

  The yoke part 32 has a cylindrical shape. The yoke part 32 is arranged along the inner peripheral surface of the housing 20. The yoke part 32 is rotatably held on the inner peripheral surface of the housing 20 by a bearing 33 as a holding mechanism. The bearing 33 is, for example, a ball bearing. The yoke part 32 provides an outer yoke. The magnet 35 is fixed to the yoke part 32.

  In the magnetic field modulation device 13, the rotor core 31 and the magnet 34 are arranged on the inner peripheral side of the container 21. In the magnetic field modulation device 13, the yoke 32, the bearing 33, and the magnet 35 are arranged on the outer peripheral side of the container 21. The magnet 34 is a first magnet arranged on one side of the container 21. The magnet 35 is a second magnet arranged on the other side of the container 21. The magnet 34 and the magnet 35 are arranged so that mutually different poles face each other on both the inner and outer sides of the container 21. The magnet 34 and the magnet 35 are arranged on the inner side and the outer side in the radial direction to supply a strong magnetic field to the MCE element 12 positioned therebetween. Rare earth magnets such as a ferrite magnet and a neodymium magnet can be used as the magnets 34 and 35.

  When the rotation shaft 22 is rotated by the motor 15, in the magnetic field modulation device 13, the magnet 34 rotates together with the rotor core 31. Further, with the rotational movement of the magnet 34, the magnet 35 facing the magnet 34 moves following the attraction force acting between the magnets, and the yoke 32 rotates. Accordingly, the configuration including the rotor core 31, the yoke portion 32, the magnet 34, and the magnet 35 becomes the magnetic field modulation device 13 that periodically provides strong excitation and demagnetization to the MCE element 12. The configuration including the rotor core 31, the yoke portion 32, the magnet 34, and the magnet 35 is the magnetic circuit portion 13A in the present embodiment. The magnetic circuit unit 13A is a relative moving body that moves relatively to the container 21. The magnetic field modulator 13 modulates the magnetic field applied to the MCE element 12 by relatively moving the container 21 and the magnetic circuit unit 13A in a direction along the outer surface of the container 21.

  The yoke portion 32 is held on the inner peripheral surface of the housing 20 by the bearing 33, but is not limited to this. For example, it may be held via a lubricating oil layer or an air layer.

  The container 21 and the magnet 34 are spaced apart from each other, so that the container 21 does not interfere with the magnet 34 even when the magnet 34 rotates together with the rotor core 31. A gap 23 is formed between the inner peripheral surface on the inner peripheral side of the outer surface of the container 21 and the outer peripheral surface on the outer peripheral side of the outer surface of the magnet 34. On the other hand, the container 21 and the magnet 35 are also spaced apart from each other, and do not interfere with the container 21 even if the magnet 35 and the yoke 32 rotate following the magnet 34. A gap 24 is formed between the outer peripheral surface on the outer peripheral side of the outer surface of the container 21 and the inner peripheral surface on the inner peripheral side of the outer surface of the magnet 35.

  The MHP device 10 includes a high-temperature system 16 that transports the high-temperature heat obtained by the MHP device 10. The high-temperature system 16 is also a thermal device that uses the heat obtained by the MHP device 10. The MHP device 10 includes a low-temperature system 17 that transports low-temperature cold heat obtained by the MHP device 10. The low-temperature system 17 is also a thermal device that uses the cold heat obtained by the MHP device 10.

  The high-temperature system 16 includes a passage 61 through which the primary medium is circulated. The high-temperature system 16 includes a heat exchanger 63 that provides heat exchange between the primary medium and another medium. For example, heat exchanger 63 provides heat exchange between the primary medium and air. The high-temperature system 16 uses the thermal output from the high-temperature end 11E1 of the MHP device 10 to radiate heat from the heat exchanger 63 and heat the external medium. The high-temperature system 16 releases the thermal output from the high-temperature end 11E1 of the MHP device 10 to the external medium by the heat exchanger 63.

  The low-temperature system 17 includes a passage 71 through which the primary medium is circulated. The low temperature system 17 includes a heat exchanger 73 that provides heat exchange between the primary medium and another medium. For example, the heat exchanger 73 provides heat exchange between the primary medium and air. The high-temperature system 16 uses the cold output from the low-temperature end 11E2 of the MHP device 10 to absorb heat in the heat exchanger 63 to cool the external medium. It can be said that the low-temperature system 17 discharges the cold output from the low-temperature end 11E2 of the MHP device 10 to the external medium by the heat exchanger 73.

  As shown in FIG. 3, an MCE element 12 composed of a block group in which a plurality of element blocks are arranged is arranged in a work room 11 in a container 21. FIG. 3 illustrates a portion of the container 21 corresponding to one working chamber 11. In the drawing, the element blocks 12A and 12B of the block group and the spacer 124 are illustrated. The number of element blocks arranged in one work chamber 11 is not limited to two. The number of element blocks arranged in one work room 11 may be three or more.

  Each of the element blocks 12A and 12B is configured by stacking element plates as element pieces. As shown in FIG. 3, the plurality of element blocks are arranged in the XX direction which is the reciprocating direction of the heat transport medium. The element plates of each element block are stacked in the YY direction orthogonal to the reciprocating direction of the heat transport medium. Hereinafter, the arrangement direction of the element blocks, which is also the reciprocating direction of the heat transport medium, may be simply referred to as the XX direction. Further, the direction in which the element plates are stacked may be simply referred to as a YY direction. An orthogonal direction orthogonal to both the XX direction and the YY direction may be referred to as a ZZ direction. The ZZ direction is also the direction in which the magnetic field modulator 13 passes the lines of magnetic force. The ZZ direction can also be said to be the direction in which the magnetic field modulator 13 applies an external magnetic field. The direction in which the external magnetic field is applied may be the YY direction.

  Each of the element blocks 12A and 12B has a plurality of element plates 121. The element plate 121 is formed in a thin rectangular parallelepiped shape. The element plate 121 has a large number of flow grooves 121a formed in a concave shape on one wide surface. As shown in FIG. 4, the flow channel groove 121 a is a groove having a rectangular cross section and extends along the XX direction. The channel groove 121a is formed so that the same cross-sectional shape is continuous in the XX direction. The element blocks 12A and 12B define a plurality of medium channels 1211 between the stacked plates. In the element blocks 12A and 12B formed by the element plate lamination, the flow channel 121a provides the medium flow channel 1211. Due to the flow channel 121a, the medium flow channel 1211 is open at both end surfaces of the element block in the XX direction.

  In the element blocks 12A and 12B, a plurality of element plates 121 are stacked in the same direction, and the element plates 121 are arranged in the opposite direction at the upper end of the stacked structure in the drawing. The uppermost element plate 121 in the figure and the lower element plate 121 are arranged such that the surfaces on which the flow channel grooves 121a are formed face each other and come into contact with each other. A spacer can be provided between element blocks adjacent to each other in the XX direction. The spacer is provided for reliably communicating the flow paths of the element blocks adjacent to each other in the XX direction.

  The thickness of the element plate 121 shown in FIG. 4 is, for example, 1 mm. The channel height dimension of the channel groove 121a is, for example, 0.8 mm. The channel height dimension is the dimension of the channel groove 121a in the YY direction. The channel width dimension of the channel groove 121a is, for example, 0.05 mm. The channel width dimension is a dimension of the channel groove 121a in the ZZ direction. In the element plate 121, a large number of flow grooves 121a are formed at the same pitch. In this example, the pitch for forming the flow channel is 0.25 mm. Therefore, the wall-shaped element portion sandwiched between the adjacent flow channel grooves 121a has a thickness of 0.2 mm.

  The plurality of flow grooves 121a are not limited to those formed at the same pitch. Further, the flow channel width of the flow channel 121a can be set to, for example, 0.025 to 0.25 mm. The flow channel 121a can be set to occupy about 15% in the width direction of the element plate 121, that is, in the ZZ direction.

  The flow channel 121a can be formed by removing a part of a rectangular parallelepiped element plate. As the removing process, dicing, wire cutting, cutting, grinding, etching, heat treatment, and the like can be employed. In this example, the flow channel 121a is formed by grooving using at least one of a dicing saw and a multi-wire saw.

  As described above, each of the element plates constituting the MCE element 12 includes a plurality of particles of the magnetic material and a binder that aggregates and holds the plurality of particles. As shown in FIG. 5, the MCE element 12, which is a magnetocaloric element, includes a plurality of particles 81 made of a magnetocaloric effect material exhibiting a magnetocaloric effect, and a resin binder 82 for aggregating and holding the plurality of particles 81. It has. The particles 81 can be particles of a lanthanum-iron-manganese-silicon compound as described above. The particles 81 preferably have an average particle size of 100 to 300 μm. Here, the average particle diameter is a central particle diameter also called a median diameter. In the present example, from the viewpoint of the magnetocaloric effect, a group of particles having a relatively large average particle diameter and a majority of particles having a diameter of 200 μm or more is adopted.

  On the other hand, the binder 82 can be an epoxy resin as described above. The binder 82 is preferably made of a material having a lower thermal conductivity than the magnetocaloric material forming the particles 81. When the heat transport medium is water or a fluid containing water, the binder 82 is preferably made of a resin material having a water absorption of 1% or less. Epoxy resin is a resin that can provide this heat conduction property and water absorption property.

  The filling rate of the plurality of particles 81 is, for example, 50% or more. That is, the volume ratio of the plurality of particles 81 in the element plate 121 can be 50% or more. In each element plate 121, the sum of the volumes of the plurality of particles 81 is set to be larger than the volume of the binder 82. In this example, the filling rate of the plurality of particles 81 is about 60%. In the element plate 121, the particles 81 are exposed on three sides of the channel groove 121a. The exposed area of the particles 81 is larger than the exposed area of the binder 82. In this example, the exposed area of the particles 81 occupies 55 to 70% on the surface inside the channel groove 121a.

  The medium channel 1211 in which the element blocks 12A and 12B are formed by the channel groove 121a can be referred to as an internal channel of the element block. As described above, the medium channel 1211 formed by the channel groove 121a is a fine channel having a relatively small channel cross-sectional area. In each of the element blocks 12A and 12B, a plurality of medium flow paths 1211 as fine flow paths are formed in a dispersed manner.

  Each medium flow channel 1211 is preferably a fine flow channel having an equivalent diameter of the flow channel cross section of 0.01 to 0.2 mm. When the equivalent diameter is less than 0.01 mm, the pressure loss of the heat transport medium is increased, and the production becomes difficult. On the other hand, when the equivalent diameter exceeds 0.2 mm, the heat exchange performance between the element and the heat transport medium is reduced, which is not preferable. From the viewpoint of suppression of pressure loss, easiness of production, and heat exchange performance, the medium flow channel 1211 preferably has an equivalent diameter of a flow channel cross section of 0.01 to 0.2 mm. The medium flow path 1211 is more preferably a fine flow path having an equivalent diameter of a flow path cross section of 0.03 to 0.15 mm. The medium flow path 1211 is more preferably a fine flow path having an equivalent diameter of a flow path cross section of 0.08 to 0.13 mm.

  The equivalent diameter here may be called an equivalent hydraulic diameter, a hydraulic equivalent diameter, or simply a hydraulic diameter. The equivalent diameter is sometimes called an equivalent diameter.

  In addition, since a large number of medium flow paths 1211 are dispersedly formed in each of the element blocks 12A and 12B, the distance to the medium flow path 1211 in any part of the element is extremely small. In any part of the element, the distance to the medium flow path 1211 is preferably 0.01 to 1.0 mm. It is not preferable to form the element such that the distance to the medium flow path 1211 is less than 0.01 mm at any of the portions, because manufacturing becomes difficult. On the other hand, it is not preferable to form an element in which the distance to the medium flow path 1211 of any part exceeds 1.0 mm, because the heat transfer distance to the heat transport medium increases. From the viewpoint of manufacturability and heat exchange performance, it is preferable that the distance to the medium flow path 1211 be 0.01 to 1.0 mm at any part of the element. Further, it is more preferable that the distance to the medium flow path 1211 is 0.03 to 0.5 mm at any part of the element. Furthermore, it is more preferable that the distance to the medium flow path 1211 is 0.05 to 0.1 mm at any part of the element.

  Of the element blocks 12A and 12B adjacent in the XX direction shown in FIG. 3, one element block 12A can be called a first element block 12A and the other element block 12B can be called a second element block 12B. In the first element block 12A, a plurality of medium flow paths 1211 extending in the XX direction are formed by flow path grooves 121a. In the second element block 12B, a plurality of medium channels 1211 extending in the XX direction are formed by the channel grooves 121a.

  The spacer 124 is disposed between two adjacent element blocks 12A and 12B in the XX direction. The spacer 124 is a frame-shaped body in this example, and has a large through hole including a plurality of openings opened at the ends of the element blocks 12A and 12B. The through holes allow communication between the plurality of medium channels 1211 provided in the element block 12A and the plurality of medium channels 1211 provided in the element block 12B. The spacer 124 can be formed of, for example, a rubber material, a resin material, or a metal material having relatively low hardness. The spacer 124 is an elastic member made of an elastic material. The spacer 124 also functions as a buffer between the element blocks 12A and 12B. The spacer 124 preferably has a heat insulating property.

  The constituent material of the spacer 124 preferably has a lower thermal conductivity than the magnetocaloric effect material forming the particles 81. The spacer can be provided integrally with the element block by, for example, projecting a binder from the element block.

  By providing the spacer 124, the element blocks 12A and 12B adjacent to each other in the XX direction are separated from each other. The portion of the through hole of the spacer 124 provides a communication gap between the element blocks 12A and 12B for communicating the medium flow paths 1211 with each other. The spacer 124 is a gap forming part that forms a communication gap between the adjacent element blocks 12A and 12B. The dimension of the communication gap in the XX direction is set to be relatively smaller than twice the heat penetration distance based on the heat penetration distance from the element block to the heat transport medium. The dimension of the communication gap in the XX direction can be, for example, 50 μm.

  In the element blocks 12A and 12B, the particles 81 are also exposed on the end faces in the XX directions facing the communication gap. Also on this surface, the exposed area of the particles 81 is larger than the exposed area of the binder 82.

  Returning to FIG. 1, the vehicle air conditioner 1 is mounted on a vehicle and adjusts the temperature of the passenger compartment of the vehicle. The two heat exchangers 63 and 73 provide a part of the vehicle air conditioner 1. The heat exchanger 63 is a high-temperature side heat exchanger that becomes higher in temperature than the heat exchanger 73. The heat exchanger 73 is a low-temperature side heat exchanger whose temperature is lower than that of the heat exchanger 63. The vehicle air conditioner 1 includes air-related equipment such as an air-conditioning duct and a blower for using the high-temperature side heat exchanger 63 and / or the low-temperature side heat exchanger 73 for indoor air conditioning.

  The vehicle air conditioner 1 is used as a cooling device or a heating device. The vehicle air conditioner 1 can include a cooler that cools the air supplied into the room, and a heater that reheats the air cooled by the cooler. The MHP device 10 is used as a cold heat source or a hot heat source in the vehicle air conditioner 1. That is, the heat exchanger 63 can be used as the heater. Further, the heat exchanger 73 can be used as the cooler.

  When the MHP device 10 is used as a heat supply source, the air that has passed through the heat exchanger 63 is supplied to the interior of the vehicle and used for heating. The air that has passed through the heat exchanger 73 is discharged outside the vehicle. At this time, the heat exchanger 63 is also called an indoor heat exchanger. The heat exchanger 73 is also called an outdoor heat exchanger.

  When the MHP device 10 is used as a cold heat supply source, the air that has passed through the heat exchanger 73 is supplied to the interior of the vehicle and used for cooling. The air that has passed through the heat exchanger 63 is discharged outside the vehicle. At this time, the heat exchanger 63 is also called an outdoor heat exchanger. The heat exchanger 73 is also called an indoor heat exchanger.

  Further, the MHP device 10 may be used as a dehumidifying device. In this case, the air that has passed through the heat exchanger 73 then passes through the heat exchanger 63 and is supplied indoors. The MHP device 10 is used as a heat source in both winter and summer.

  Next, a method for manufacturing the magnetocaloric element having the above-described configuration will be described. When manufacturing the MCE element 12, as shown in FIG. 6, a mixing step 110, a molding step 120, a particle exposure step 130, a lamination step 140, and an arrangement step 150 are performed.

  In the mixing step 110, a large number of the supplied particles 81 are mixed with the uncured epoxy resin serving as the resin binder 82 to obtain a mixture. The uncured epoxy resin serving as the resin binder 82 is a fluid resin exhibiting fluidity. For mixing the particles 81 and the fluid resin, for example, a mixer having a rotating blade can be used. In the mixing step 110, various mixers, mixers, and the like can be used. In the mixing step 110, a mixture in which many particles 81 are randomly dispersed in a fluid resin is obtained.

  The mixing step 110 corresponds to a preparation step of preparing a mixture in which a plurality of particles 81 made of a magnetocaloric material exhibiting a magnetocaloric effect and a fluid resin exhibiting fluidity are mixed. Note that the preparation step is not limited to the mixing step 110, and may be a step of preparing a mixture and supplying the mixture to a subsequent step.

  In the molding step 120, the mixture created in the mixing step 110 is molded by a compression molding machine or the like. The forming process in the forming step 120 is not limited to compression molding, but may be transfer molding or injection molding. A heating device including, for example, a heater is provided in the molding die. The mixture filled in the cavity of the mold in the molding step 120 is heated by the heating device and rises in temperature due to self-heating during curing, whereby the fluid resin is cured to become the resin binder 82.

  As described above, in the molding step 120, the fluid resin in the mixture is solidified by curing, and the mixture is molded such that the plurality of particles 81 are held by the resin binder 82 obtained by solidifying the fluid resin. Here, in the molding step 120, it is preferable that the temperature of the mixture be maintained lower than the Curie temperature of the magnetocaloric effect material constituting the particles 81. Thereby, the particles 81 can maintain the ferromagnetic property.

  A surface layer, also called a skin layer, is formed on the surface of the molded body obtained in the molding step 120. This surface layer does not include, for example, the particles 81 and is formed only by the resin binder 82. In the cavity of the molding die, the flowable resin forms a thin film layer along the inner surface of the cavity, and the inside thereof is easily filled with the mixture of the particles 81 and the flowable resin. Thereby, a skin layer is easily formed on the molded body.

  In the particle exposing step 130, a process of exposing the particles 81 by removing the skin layer formed on the molded body in the molding step 120 is performed. Therefore, the particle exposing step 130 can be called a removing step. In the particle exposing step 130, as described above, the channel groove 121a without a skin layer is formed by grooving using at least one of a dicing saw and a multi-wire saw. In the particle exposing step 130, it is preferable that the skin layer is also removed from the surface of the element plate 121 opposite to the channel groove forming surface. The surface is a surface facing the medium flow channel 1211 together with the inner surface of the flow channel 121a. A part of the surface is a surface portion surrounding the medium flow path 1211 together with the inner surface of the flow path groove 121a. Also on this surface, the particles 81 are exposed, and the exposed area of the particles 81 is made larger than the exposed area of the binder 82.

  Further, in the particle exposing step 130, the particles 81 are exposed on the surfaces that become the end surfaces in the XX direction in each of the element blocks 12A and 12B. Also on this surface, the exposed area of the particles 81 is made larger than the exposed area of the binder 82. As described above, in the particle exposing step 130, at least a part or all of the surface that comes into contact with the heat transport medium is subjected to a process of exposing the particles 81. Then, the exposed area of the particles 81 is made larger than the exposed area of the binder 82.

  In the laminating step 140, the element plates 121 that have been subjected to the particle exposing step 130 are laminated to form the element blocks 12A and 12B as shown in FIG. Then, in the arrangement step 150, the element blocks 12A and 12B, which are the laminates formed in the lamination step 140, are arranged in the XX direction together with the spacers 124, thereby completing the MCE element 12.

  According to the disclosed embodiment, the following effects can be obtained.

  The MCE element 12 includes a plurality of particles 81 made of a magnetocaloric material exhibiting a magnetocaloric effect, and a binder 82 for aggregating and holding the plurality of particles, and a medium flow path 1211 through which a heat transport medium can flow. Is an element formed with. Then, on the surface facing the medium flow path 1211, the exposed area of the particles 81 is larger than the exposed area of the binder 82.

  According to this, the particles 81 made of the magnetocaloric material are exposed on the surface facing the medium flow path 1211, and the exposed area of the particles 81 is larger than the exposed area of the binder 82. Therefore, the thermal resistance on the surface facing the medium flow path 1211 can be reduced. Thus, the heat exchange efficiency between the magnetocaloric element 12 and the heat transport medium can be improved.

  FIG. 8 is a model diagram of a comparative example in which a skin layer 91 consisting of only the binder 82 is formed on the surface of the element core portion containing 60% by volume of the particles 81 and 40% by volume of the binder 82. On the other hand, FIG. 7 is a model diagram of a disclosed example in which a portion having the same thickness is formed only of an element core portion containing 60% by volume of particles 81 and 40% by volume of binder 82. In each model diagram, the illustrated left-right direction is the heat transfer direction.

  Generally, a relationship of thermal resistance = thickness / (thermal conductivity × area) is known. In the configuration exemplified in the present embodiment, the thermal conductivity of the mixed material including the particles 81 and the binder 82 is 2 (W / m ° C.), and the thermal conductivity of the constituent material of the binder 82 is 0.2 (W / m ° C.). W / m ° C).

  In the model of the disclosed example configuration shown in FIG. 7, the thermal resistance is 0.21 / 2 A = 0.105 A (° C./W). On the other hand, in the model of the comparative example configuration shown in FIG. 8, the thermal resistance is 0.2 / 2A + 0.01 / 0.2A = 0.15A (° C./W). Here, A is an area. As is clear from this relationship, by employing the configuration of the disclosed example in which the particles 81 are exposed, the thermal resistance can be significantly reduced.

  In the MCE element 12 of the present embodiment, the binder 82 is made of a material having a lower thermal conductivity than the magnetocaloric material. According to this, in the magnetocaloric element that easily suppresses heat transfer in the flow direction of the heat transport medium, the heat exchange efficiency between the magnetocaloric element and the heat transport medium can be reliably improved.

  The medium flow path 1211 is a fine flow path having an equivalent diameter of 0.01 to 0.2 mm. According to this, it is possible to provide a medium flow path that achieves both high heat exchange performance and suppression of pressure loss of the heat transport medium and easy production of the element.

  The medium flow path 1211 is preferably a fine flow path as described above. In order to improve the heat exchange performance, the higher the heat transfer coefficient between the element and the medium, the better. The heat transfer coefficient h is defined by the following equation.

h = Nu · k / L
Here, h is the heat transfer coefficient (= heat flow velocity density / (element surface temperature−medium temperature)), Nu is the Nusselt number, k is the heat transfer coefficient of the medium, and L is the equivalent diameter.

  Nu changes depending on the shape, but hardly changes because the heat transport medium flow is laminar. In order to increase the heat transfer coefficient as much as possible, it is desirable to reduce the equivalent diameter L as much as possible, but there is a trade-off with the pressure loss. Therefore, it is preferable to set 0.01 to 0.2 mm as an equivalent diameter capable of achieving both a pressure loss and a heat transfer coefficient.

  In the MCE element 12, a plurality of fine channels are formed in a dispersed manner. According to this, the heat exchange performance can be reliably improved, and the output density can be improved.

  In addition, in any of the MCE elements 12, the distance to the microchannel is 0.01 to 1.0 mm. According to this, the heat transfer between the particles 81 inside the element and the heat transport medium can be efficiently performed, and the heat exchange performance can be more reliably improved.

  The MCE element 12 is configured by arranging a plurality of element blocks 12A and 12B each having a medium flow path 1211 formed therein. Medium flow paths 1211 are opened at both end surfaces in the arrangement direction of the element blocks, and adjacent element blocks in the arrangement direction are separated from each other. In the element block, the exposed area of the particles 81 is larger than the exposed area of the binder 82 even at the end face in the arrangement direction. According to this, the heat exchange efficiency between the magnetocaloric element 12 and the heat transport medium can be improved even at the end face facing the gap between the element blocks.

  The MHP device 10 according to the present embodiment includes a magnetocaloric element 12 and a heat transport device 14 that reciprocates a heat transport medium in a medium flow path 1211 so as to generate a high-temperature end and a low-temperature end in the magnetocaloric element 12. And According to this, the output density at the high temperature end and the low temperature end of the magnetocaloric element 12 can be reliably improved.

(Other embodiments)
The technology disclosed in this specification can be implemented in various modifications without being limited to the embodiments for implementing the disclosed technology. The disclosed technology can be implemented by various combinations without being limited to the combinations shown in the embodiments. Embodiments can have additional parts. Parts of the embodiments may be omitted. A part of the embodiment can be replaced with or combined with a part of another embodiment. The structure, operation, and effect of the embodiment are merely examples. The technical scope of the disclosed technology is not limited to the description of the embodiments. Some technical ranges of the disclosed technology are indicated by the description of the claims, and should be understood to include meanings equivalent to the description of the claims and all modifications within the scope. .

  In the above embodiment, each element block of the MCE element 12 is configured by laminating only the element plate 121 on which the flow channel 121a is formed, but the invention is not limited to this. Each element block can be configured by combining various element plates and element pieces, or an integrated element block can be adopted.

  For example, instead of the flow channel groove 121a having a rectangular cross section, an element block 121 having a flow channel groove 121b having a triangular cross section as shown in FIG. Good. Further, an element block having a fine channel may be formed by stacking element plates 121 provided with a channel groove 121c having a trapezoidal cross section as shown in FIG. In addition, as shown in FIG. 11, a large number of through holes 121d serving as fine channels may be formed in the element plate 121 to form an element block.

  The number of fine channels as the medium channel is not limited to those having the same shape, and for example, a plurality of types of micro channels having different cross-sectional shapes may be employed. Further, as long as a large number of fine channels are formed in a dispersed manner in the element, the invention is not limited to those formed in a uniformly dispersed manner.

  Further, the medium flow path is not limited to a fine flow path having an equivalent diameter of 0.01 to 0.2 mm. It is sufficient that the exposed area of the particles made of the magnetocaloric material is larger than the exposed area of the binder on the surface surrounding the medium flow path. For example, an element block having a medium flow path may be formed by stacking element plates provided with triangular flow grooves 121e having a relatively large cross-sectional area as shown in FIG. Further, an element block provided with one relatively shallow rectangular channel groove 121f as shown in FIG. 13 may be laminated to form an element block.

  Further, in each of the above embodiments, a plurality of medium flow paths extending in the XX direction are formed in each element block, but the invention is not limited to this. The number of medium flow paths is not limited to those exemplified in the above embodiment. The number of medium flow paths may be smaller than the number illustrated in the figure. Further, the number may be larger than the number illustrated in the figure. Furthermore, the medium flow path is not limited to the one that linearly extends in the XX direction as in the above embodiments. For example, as long as a reciprocating flow of the heat transport medium can be formed in the working room in the XX direction, the medium flow path may be slightly bent.

  In each of the above embodiments, the particles 81 and the binder 82 are each formed of a single material. However, the present invention is not limited to this. The plurality of particles 81 may be a mixture of particles of different materials. Further, the binder 82 may be, for example, a mixture of plural kinds of resin materials.

  Further, in each of the above embodiments, the magnetic field modulation device of the magnetic heat pump device is configured such that the first magnet and the yoke arranged on one side of the container and the different poles facing the first magnet on the other side of the container. A second magnet and a yoke arranged. Then, a driving device connected to the first magnet and the yoke, and a holding mechanism for holding the second magnet and the yoke so as to rotate following the first magnet and the yoke are provided. However, it is not limited to this.

  For example, an external drive mechanism for externally driving the yoke to which the second magnet is attached may be provided, and the second magnet and the yoke may be rotated following the first magnet and the yoke. The drive source of the external drive mechanism may be a drive device for rotating the yoke to which the first magnet is attached, or a drive device different from the drive device for rotating the yoke to which the first magnet is attached. You may.

  Further, in each of the above embodiments, the magnetic circuit portion has the magnet 34 as the first magnet and the magnet 35 as the second magnet facing each other with the container interposed therebetween, but is not limited thereto. Not something. For example, the magnetic circuit unit may include only one of the first magnet and the second magnet.

  In each of the above embodiments, the configuration in which the container 21 as the element bed is kept stationary and the magnets 34 and 35 are rotated is adopted. Alternatively, various configurations for providing relative rotation between the container 21 which is an element bed and the magnetic field modulation device 13 can be adopted. For example, the container, which is an element bed having the working room 11 and the MCE element 12, may be rotated relative to a magnetic field modulator including a permanent magnet. Thus, the magnetic field applied to one MCE element 12 can be changed. In other words, the magnetic field modulation device may move the container in a direction along the outer surface of the container with respect to the relative moving body having the magnet. That is, it is only necessary to move the container and the relative moving body relatively in the direction along the outer surface of the container and change the magnitude of the magnetic field applied to the magnetic work material.

  Further, in each of the above embodiments, the pumps as the heat transporting medium moving devices are provided on both sides of the container having the high temperature end and the low temperature end, but the present invention is not limited to this. For example, a container having a high-temperature end and a container having a low-temperature end may be arranged on both sides of the pump. Further, the form of the pump is not limited to the type described above.

  In each of the above embodiments, the magnetic field modulation device includes a magnetic circuit unit having a permanent magnet as a magnetic force source, and modulates an external magnetic field applied to the magnetic work material by relatively moving the magnetic circuit unit and the container. I was Further, it has been described that the magnetic force source is not limited to the permanent magnet, but may be an electromagnet. When an electromagnet is used as the magnetic force source, the magnetic field modulator does not have to perform the relative movement between the magnetic circuit unit and the container. When an electromagnet is used, the magnetic field can be modulated without any relative movement between the magnetic circuit unit and the container.

  In each of the above embodiments, the heat transport medium is supplied to the heat exchangers 63 and 73 outside the MHP device. Instead, a heat exchanger for exchanging heat between the primary medium, the heat transport medium, and the secondary medium may be provided in the MHP device, and the secondary medium may be supplied to the low-temperature system and the high-temperature system.

  In the above embodiments, the disclosed technology is applied to the vehicle air conditioner. Instead, the disclosed technology may be applied to an air conditioner for a moving body such as a ship or an aircraft other than a vehicle. Further, the disclosed technology may be applied to a stationary air conditioner for a house or the like. Further, it may be used as a water heater for heating water or a water cooler for cooling water. In the above-described embodiment, the MHP apparatus using outdoor air as a main heat source has been described. Alternatively, another heat source, such as water or soil, may be used as the main heat source.

  Further, in each of the above embodiments, an MHP device which is an embodiment of a thermomagnetic cycle device is provided. Alternatively, a thermomagnetic engine device which is an embodiment of a thermomagnetic cycle device may be provided. For example, a thermomagnetic engine device can be provided by adjusting the phase of the magnetic field change and the flow of the heat transport medium of the MHP device of the above embodiment.

10 Magnetocaloric effect type heat pump device (MHP device, magnetic heat pump device)
11 working room 12 magnetocaloric element (MCE element, magnetic working material)
12A, 12B Element block 13 Magnetic field modulator 14 Heat transport device 21 Container 81 Particles 82 Binder 121 Element plate 121a Channel groove 1211 Medium channel

Claims (7)

A plurality of particles (81) of a magnetocaloric material exhibiting a magnetocaloric effect;
A binder (82) for aggregating and holding the plurality of particles,
A magnetocaloric element in which a medium flow path (1211) through which a heat transport medium can flow is formed,
A magnetocaloric element, wherein an exposed area of the particles is larger than an exposed area of the binder on a surface facing the medium flow path.   The magnetocaloric element according to claim 1, wherein the binder is made of a material having a lower thermal conductivity than the magnetocaloric effect material.   The magnetocaloric element according to claim 1, wherein the medium flow path is a fine flow path having an equivalent diameter of 0.01 to 0.2 mm.   The magnetocaloric element according to claim 3, wherein the plurality of fine channels are formed in a dispersed manner.   The magnetocaloric element according to claim 4, wherein the distance to the microchannel is 0.01 to 1.0 mm at any part. A plurality of element blocks (12A, 12B) each having the medium flow path formed therein,
The medium flow path is opened at both end faces in the arrangement direction of the element blocks, and the element blocks adjacent in the arrangement direction are separated from each other,
The magnetocaloric element according to any one of claims 1 to 5, wherein the element block has an exposed area of the particles larger than an exposed area of the binder even at an end face in the arrangement direction. A magnetocaloric element (12) according to any one of the preceding claims,
A heat transport device (14) for reciprocating the heat transport medium in the medium flow path so as to generate a high-temperature end and a low-temperature end in the magnetocaloric element.

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