JP2008249175A - Magnetic refrigerating device and method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a magnetic refrigerating device capable of reducing load to environment as it is free from chlorofluorocarbon, and having high efficiency though it is compact, and to provide a magnetic refrigerating method using the magnetic refrigerating device. <P>SOLUTION: This magnetic refrigerating device comprises magnetic fluid placed to be kept into contact with a magnetic body, a magnetic field applying means for applying magnetic field to the magnetic body, and a magnetic field applying/removing means for repeatedly applying and removing magnetic field to the magnetic body by reciprocating the magnetic field applying means in the prescribed direction. The magnetic fluid is heated and cooled by heat absorption and heat generation of the magnetic body caused by application and removal of magnetic field, and moved by magnetic attraction force caused by movement of the magnetic field applying means to form a high-temperature portion and a low-temperature portion at both ends of the magnetic body. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a magnetic refrigeration device and a magnetic refrigeration method capable of realizing refrigeration from a room temperature range to about −100 ° C. with a relatively low magnetic field using a magnetic material having a magnetocaloric effect.

Currently, most of refrigeration technologies in the room temperature range, which are closely related to human daily life; for example, refrigerators, freezers, indoor air conditioning, etc., use gas compression / expansion cycles. However, with regard to the refrigeration technology based on the gas compression / expansion cycle, environmental destruction due to the environmental discharge of specific chlorofluorocarbon gas becomes a serious problem, and there is a concern about the influence of alternative chlorofluorocarbon gas on the environment. Recently, improvements have been made using natural refrigerants (CO ₂ etc.) and isobutane.

  Against this background, there is a demand for practical use of a clean and highly efficient refrigeration technique that does not have the problem of environmental destruction associated with the disposal of working gas.

  In recent years, as one of such environmentally friendly and highly efficient refrigeration technologies, expectations for magnetic refrigeration have increased, and research and development of magnetic refrigeration technologies for room temperature regions have been activated. In 1881, Warburg discovered the magnetocaloric effect in iron (Fe). The magnetocaloric effect is a phenomenon in which, when an externally applied magnetic field is changed with respect to a magnetic substance in an adiabatic state, the temperature of the magnetic substance changes. In magnetic refrigeration, a low temperature is generated as follows using the magnetocaloric effect.

  In a magnetic substance, entropy changes due to the difference in the degree of freedom of the electron magnetic spin system between a state when a magnetic field is applied and a state when a magnetic field is removed. With such entropy change, entropy shift occurs between the electron magnetic spin system and the lattice system. Magnetic refrigeration uses a magnetic material with a large electron magnetic spin, and transfers entropy between the electron magnetic spin system and the lattice system by using a large entropy change between when the magnetic field is applied and when the magnetic field is removed. This produces a low temperature.

The magnetic refrigeration system is a paramagnetic salt such as Gd ₂ (SO ₄ ) ₃ / 8H ₂ O and Gd ₃ Ga ₅ O ₁₂ (gadolinium gallium garnet; GGG). A refrigeration system using paramagnetic compounds represented by) was developed. The refrigeration system that achieves magnetic refrigeration using paramagnetic substances is mainly applied to the cryogenic region below 20K, and uses a magnetic field of about 10 Tesla that can be obtained using a superconducting magnet. Yes.

In contrast, since the 1970s, magnetic refrigeration using a magnetic phase transition between a paramagnetic state and a ferromagnetic state in a ferromagnetic material has been actively conducted in order to achieve magnetic refrigeration at a higher temperature. Lanthanum rare earth elements such as Nd, Dy, Er, Tm, and Gd and two or more rare earth alloy materials such as Gd-Y and Gd-Dy, RAl ₂ (R represents a rare earth element, The same), and many magnetic materials containing rare earths having a large electron magnetic spin per unit volume, such as rare earth intermetallic compounds such as RNi ₂ and GdPd.

  In 1974, Brown in the United States realized magnetic refrigeration at room temperature for the first time using a ferromagnetic material Gd having a ferromagnetic phase transition temperature (Tc) of about 294K. However, in Brown's experiment, although the refrigeration cycle was operated continuously, it did not reach a steady state. In 1982, Barclay of the United States devised the active use of lattice entropy, which has been positioned as an impediment to magnetic refrigeration at room temperature, so that it can be used in magnetic refrigeration work using magnetocaloric effects. In addition, we proposed a refrigeration system that simultaneously bears the heat storage effect of storing the cold generated by this magnetic refrigeration operation (US-Pat. 4332135). This magnetic refrigeration method is called the AMR method ("Active Magnetic Refrigeration"). Both of these refrigeration systems operate under a strong magnetic field using a superconducting magnet.

  In 1997, Zimm, Gschneidner, Pecharsky et al. Of the United States made a prototype AMR magnetic refrigerator using a filled cylinder filled with fine spherical Gd, and succeeded in continuous steady operation of the magnetic refrigeration cycle at room temperature. . According to this, by changing the magnetic field from 0 Tesla to 5 Tesla by using a superconducting magnet in the room temperature range, when the freezing temperature difference (ΔT) is 13 ° C. It has been reported that very high refrigeration efficiency (COP = 15; except for the input power to the magnetic field generating means) was obtained. Incidentally, the refrigeration efficiency (COP) of a household refrigerator or the like in a compression cycle using conventional chlorofluorocarbon is about 1 to 3.

In 2000, there was a report using permanent magnets at Bohigas et al. In Spain. This is a structure in which a magnetic refrigeration working material with a rotational drive system is inserted into a gap between fixed opposing permanent magnets. Gd is used as the magnetic refrigeration material, and cooling at 1.5 ° C. is demonstrated in a room temperature environment under the conditions of magnetic field strength: 0 T, refrigerant: olive oil, and rotation speed: 4-50 rpm, but the refrigerant is used in the rotational drive system. The problem is a complicated structure with built-in circulation and insufficient cooling capacity.
USP4,332,135

  The present invention is a problem of the above-mentioned magnetic refrigeration technology, such as the use of ultra-low temperature regions and superconducting magnets to increase the size and use of large electric power or the use of permanent magnets in recent years. There are many, and it has been devised as a solution to these problems. An object of the present invention is to provide a magnetic refrigeration device that is small in size and high in efficiency, such as chlorofluorocarbon-free, and a magnetic refrigeration method using such a magnetic refrigeration device.

In order to achieve the above object, one embodiment of the present invention provides:
A magnetic material having a magnetocaloric effect;
A magnetic fluid configured to be in contact with the magnetic body;
A magnetic field applying means for applying a magnetic field to the magnetic body;
Magnetic field application removing means that repeats application and removal of the magnetic field to and from the magnetic body by reciprocating the magnetic field application means in a predetermined direction,
The magnetic fluid is heated and cooled by heat absorption and heat generation of the magnetic body resulting from application and removal of the magnetic field, and is moved by a magnetic attraction force resulting from movement of the magnetic field application means, whereby the magnetic body The present invention relates to a magnetic refrigeration device characterized in that a high-temperature part and a low-temperature part are generated at both ends.

  In the conventional AMR system as described above, in order to sequentially apply and remove the magnetic field to and from the magnetic body constituting the magnetic refrigeration device, a control device for driving the magnetic field generating means, for example, an actuator, and the magnetic body It was necessary to separately provide a refrigerant driving device for flowing a refrigerant and generating a high temperature part and a low temperature part in the flow direction of the magnetic material. That is, in order to realize an AMR magnetic refrigeration device, it is necessary to provide at least both a driving device for the magnetic field generating means and a driving device for the refrigerant and drive them.

  On the other hand, in the above aspect of the present invention, a magnetic fluid is used as the refrigerant, and a single driving device that is a magnetic field application removing unit provided with a magnetic field generating unit for applying a magnetic field to the magnetic material is used to drive this. By moving the apparatus in the length direction of the magnetic body, the magnetic body is moved by utilizing the magnetic attraction force with respect to the magnetic fluid caused by the magnetic field applied to and removed from the magnetic body. It moves in the direction. Therefore, as in the conventional AMR method, the refrigerant (magnetic fluid) is sequentially heated and cooled by utilizing the sequential heat absorption and heat generation of the magnetic material, so that the high temperature portion and the low temperature in the flow direction of the magnetic material. Part can be produced and a magnetic refrigeration device can be constructed.

  However, in the above-described aspect of the present invention, only a single driving device that is a magnetic field application removing unit including a magnetic field generating unit for applying a magnetic field to the magnetic body is used, and a separate refrigerant driving unit ( There is no need to provide a device. Therefore, since the number of drive devices can be reduced as compared with the above-described conventional magnetic refrigeration device, a small and highly efficient magnetic refrigeration device can be provided.

  In the present invention, the “longitudinal direction of the magnetic material” means the long axis direction of the magnetic material, and coincides with the driving direction of the magnetic field application removing means with respect to the magnetic material. For example, when the magnetic substance is magnetic particles and is filled in a predetermined container, and the magnetic field application / removal means is driven along the outer peripheral surface length direction of the container, the outer periphery of the container It means the surface length direction.

  In another aspect of the present invention, the magnetic fluid may be a temperature sensitive magnetic fluid. In this thermosensitive magnetic fluid, the magnetism (magnetization) changes depending on the temperature, and generally the magnetization tends to decrease as the temperature rises. Therefore, as described above, after the magnetic field is applied to the magnetic material from the magnetic field generating means, the magnetic material generates heat due to the magnetocaloric effect due to the application of the magnetic field, and the temperature of the magnetic fluid rises. Becomes smaller. Therefore, the movement of the magnetic fluid is delayed as compared with the application of the magnetic field from the magnetic field generating means. By generating such a delay time, the heat separation between the high temperature part and the low temperature part can be performed efficiently, so that a highly efficient magnetic refrigeration device can be provided.

  In another aspect of the invention, the magnetic field generating means may be a permanent magnet circuit. In this case, the magnetic field generating means can be reduced in size, and the overall size of the magnetic refrigeration device can be reduced.

  Furthermore, in another aspect of the present invention, a valve and a valve opening / closing mechanism for moving the magnetic fluid in the length direction of the magnetic body using a pressure difference can be provided. In this case, since the movement of the magnetic fluid can be moved not only in the magnetic attraction force as described above but also in the length direction of the magnetic body using the pressure difference, the magnetic fluid (refrigerant) is more efficiently used. Can be moved. Therefore, a more efficient magnetic refrigeration device can be provided.

  In another aspect of the present invention, the valve opening / closing mechanism is configured to open and close the valve in synchronization with the magnetic field application removing means. As a result, the magnetic attractive force and the pressure due to opening and closing of the valve are simultaneously applied to the magnetic fluid, so that the magnetic fluid (refrigerant) can be moved more efficiently. Therefore, a more efficient magnetic refrigeration device can be provided.

  Further, in the above aspect, the magnetic field application removing means includes a spring member, and the opening and closing of the valve can be performed with a mechanical delay accompanying expansion and contraction of the spring member. In this case, since the magnetic attractive force and the pressure due to opening and closing of the valve are applied to the magnetic fluid with the delay, the magnetic fluid (refrigerant) can be moved more effectively. For example, even after the magnetic attractive force is removed, the magnetic fluid (refrigerant) can be moved at the remaining pressure because the pressure remains. Even when the pressure is not generated, only the magnetic attractive force can be applied first to move the magnetic fluid (refrigerant).

  As described above, according to the above-described aspects of the present invention, a magnetic refrigeration device having a small size and high efficiency, such as a freonless, and a magnetic refrigeration method using such a magnetic refrigeration device are provided. Can do.

  Below, the magnetic refrigeration device and the magnetic refrigeration method concerning this invention are demonstrated based on specific embodiment.

  FIG. 1 is a basic configuration diagram relating to an example of a magnetic refrigeration device of the present invention. In FIG. 1, reference numeral 1 denotes a magnetic body (magnetic material) having a magnetocaloric effect, which is used by being partitioned and filled with a separator 4 in a container 7. The magnetic circuit 2 is a magnetic field generating means, and is operated by a moving mechanism that applies and removes a magnetic field to and from the magnetic material 1 described below. This moving mechanism will be described in detail with reference to a drive system diagram (an explanatory diagram) of the magnetic refrigeration device shown later.

  The container 7 is filled with the refrigerant 3, and a refrigerant moving unit (not shown) is attached thereto. Normally, the refrigerant is moved by a pump, a piston, or the like, but in this embodiment, the refrigerant is moved by using a magnetic field generation unit as described in detail below. Generally, various oil-based refrigerants, solvent-based refrigerants including ethanol, water, and a mixture thereof are used as the refrigerant. In this embodiment, a magnetic fluid, preferably a temperature-sensitive magnetic fluid is used.

  The refrigeration cycle in the magnetic refrigeration device will be described. First, when the magnetic circuit 2 is opposed to the magnetic material 1, a magnetic field is applied to change the magnetization of the magnetic material 1, and the temperature of the magnetic material 1 increases due to the entropy change associated therewith. Next, the refrigerant is moved in either the left or right refrigerant flow direction. Next, the magnetic circuit 2 is moved away from the magnetic material 1, and the temperature of the magnetic material 1 is lowered by the same magnetocaloric effect. Next, the refrigerant is moved in the refrigerant flow direction different from the previous one. By repeating these series of refrigeration cycles, a temperature difference occurs between the low temperature end and the high temperature end. This method is called an AMR method (“Active Magnetic Refrigeration”), and utilizes both the temperature change of the magnetic material itself due to the magnetocaloric effect of the magnetic material and the effect of the magnetic material itself storing heat.

  The low end obtained here can supply a low temperature, for example in a freezer, with a heat exchanger (not shown). Moreover, the high temperature end can be used for the purpose of radiating heat to the outside air with a heat exchanger (not shown) or heating an object.

  FIG. 2 and FIG. 3 show drive system diagrams (descriptions) of the magnetic refrigeration device in the present embodiment with respect to the basic configuration of the magnetic refrigeration device of FIG. FIG. 2 shows an operation state when a magnetic field is applied, and FIG. 3 shows an operation state when the magnetic field is removed. The magnetic material 1 is a Gd sphere and is filled in a container 7 having a structure held by a separator 4. The refrigerant 3 is a magnetic fluid.

  When the magnetic circuit 2 fixed to the linear drive actuator 11 moves in the direction of the magnetic material 1, the magnetic material 1 and the magnetic circuit 2 come to the same position, thereby applying a magnetic field (magnetic field ON), and the magnetic material 1 has a magnetocaloric effect. Generates heat and the temperature of the magnetic fluid (refrigerant) 3 rises. The magnetic fluid (refrigerant) 3 receives a magnetic torque (magnetic attractive force) due to the magnetic field of the magnetic circuit 2 and moves to the right so as to come into contact with the magnetic material 1. In this way, the temperature on the high temperature end 6 side increases.

  Next, as shown in FIG. 3, the magnetic circuit 2 fixed to the linear drive actuator 11 is moved away from the magnetic material 1. When the magnetic material 1 and the magnetic circuit 2 are separated, the magnetic field is removed (magnetic field OFF), the magnetic material 1 is cooled by the magnetocaloric effect, and the temperature of the magnetic fluid (refrigerant) 3 is also lowered. The magnetic fluid (refrigerant) 3 receives the magnetic torque generated by the magnetic field of the magnetic circuit 2 and moves in the moving direction of the magnetic circuit 2. In this way, the temperature on the low temperature end 5 side is lowered.

  As described above, in the magnetic refrigeration device of this embodiment, when the refrigerant 3 is moved, it is not necessary to provide a moving means for the refrigerant 3 in addition to the linear drive actuator for driving the magnetic circuit 2. The magnetic refrigeration device can be miniaturized and its efficiency can be increased.

  The magnetic fluid (refrigerant) 3 is moved to the right (high temperature end side) so as to be in contact with the magnetic material 1 due to the influence of the pressure due to the pressure difference in addition to the magnetic torque (magnetic attraction force) described above. It is possible.

  The magnetic field sensitive on / off valve 8 is opened by the magnetic field of the magnetic circuit 2, and the linear moving on / off valve 9 is closed by the piston 10 fixed to the linear drive actuator 11. By opening and closing such a valve, a pressure difference (the low temperature end 5 is high pressure and the high temperature end 6 is low pressure) occurs in the length direction of the magnetic material 1, that is, between the high temperature end 6 and the low temperature end 5. In other words, in the present embodiment, the magnetic fluid (refrigerant 3) moves to the right (high temperature end side) under the influence of magnetic torque (magnetic attraction force) and pressure. As a result, the magnetic fluid (refrigerant) 3 can be moved more efficiently, and a magnetic refrigeration device with higher efficiency can be provided.

  Further, when the piston 10 fixed to the linear drive actuator 11 is separated from the linear moving on-off valve 9, the valve is opened, and further, the magnetic field of the magnetic circuit 2 is weakened, and the magnetic field sensitive on-off valve 8 is closed, so that the high temperature end. A pressure difference (low temperature end 5 is low pressure and high temperature end 6 is high pressure) is generated between 6 and the low temperature end 5. Therefore, the magnetic fluid (refrigerant) 3 is in the left direction (low temperature end side) so as to come into contact with the magnetic material 1 due to the influence of the pressure caused by the pressure difference in addition to the magnetic torque (magnetic attraction force) described above. To move on. In other words, in the present embodiment, the magnetic fluid (refrigerant) 3 moves to the right (low temperature end side) under the influence of magnetic torque (magnetic attraction) and pressure. As a result, the magnetic fluid (refrigerant) 3 can be moved more efficiently, and a magnetic refrigeration device with higher efficiency can be provided.

  2 and 3, that is, by repeating the magnetic field ON-OFF cycle, the heated magnetic fluid (refrigerant) 3 moves to the right (high temperature end), and the cooled magnetic fluid ( Since the refrigerant 3) moves in the left direction (low temperature end), the temperature difference between the low temperature end 5 and the high temperature end 6 opens, and finally becomes a steady state in a heat balanced state. Thus, it is possible to provide a magnetic refrigeration device.

  4 and 5 are configuration diagrams showing modifications of the above embodiment. In these drawings, only the characteristic part is enlarged and the same reference numerals are used for similar or identical components.

  As shown in FIGS. 4 and 5, in this embodiment, the linear movement type on-off valve 9 is accommodated in the spring device 12. A spring member 12a is provided on the front side (left side) of the spring device 12, and a spring member 12b is provided on the rear side (right side). Note that there is a relationship of (spring constant of the spring member 12a) <(spring constant of the spring member 12b). Further, above and below the spring device 12, the magnetic fluid (refrigerant) 3 circulates so as to communicate with the flow hole 9 a of the magnetic fluid (refrigerant) 3 formed therein as the valve 9 moves. Holes 12c and 12d are provided.

  As shown in FIG. 4, when the linear drive actuator 11 moves in the direction of the magnetic material 1, the spring members 12 a and 12 b in the spring device 12 are compressed by the piston 10. Then, the valve 9 in the spring device 12 is driven in a state mechanically delayed from the drive of the linear drive actuator 11 (piston 10) by the expansion and contraction force of the spring members 12a and 12b, and the spring device 12 in the flow hole 9a. The communication with the flow holes 12c and 12d is released. As a result, the valve 9 is closed.

  On the other hand, since the magnetic field sensitive on-off valve 8 is opened by the magnetic field of the magnetic circuit 2, the pressure difference between the length direction of the magnetic material 1, that is, between the high temperature end 6 and the low temperature end 5 (the low temperature end 5 is high pressure). The high temperature end 6 has a low pressure). Therefore, the magnetic fluid (refrigerant) 3 comes into contact with the magnetic material 1 not only by the magnetic torque (magnetic attractive force) caused by the magnetic field from the magnetic circuit 2 but also by the pressure caused by the pressure difference. And move to the right (high temperature end side).

  Next, as shown in FIG. 5, when the linear drive actuator 11 moves away from the magnetic material 1, the pressure of the spring members 12 a and 12 b in the spring device 12 by the piston 10 is released, and the valve 9 is moved to the spring device 12. It will return to its original position. Therefore, the valve 9 is opened. On the other hand, when the magnetic field of the magnetic circuit 2 is weakened and the magnetic field sensitive on-off valve 8 is closed, a pressure difference (the low temperature end 5 is low pressure and the high temperature end 6 is high pressure) is generated between the high temperature end 6 and the low temperature end 5. Therefore, the magnetic fluid (refrigerant) 3 is in the left direction (low temperature end side) so as to come into contact with the magnetic material 1 due to the influence of the pressure caused by the pressure difference in addition to the magnetic torque (magnetic attraction force) described above. To move on.

  In this embodiment, since the valve 9 is opened and closed using the spring members 12a and 12b, the magnetic torque (magnetic attractive force) and the pressure due to opening and closing of the magnetic fluid (refrigerant) 3 cause the delay. Along with this, it is applied. Therefore, the magnetic fluid (refrigerant) 3 can be moved more effectively. In fact, even after the magnetic torque (magnetic attractive force) is removed, the magnetic fluid (refrigerant) 3 can be moved by the remaining pressure difference because the pressure difference remains. Even when the pressure difference does not occur, the magnetic fluid (refrigerant) can be moved by applying only the magnetic torque (magnetic attractive force) first.

  FIG. 6 shows the time dependence of the temperature change of the low temperature end 5 and the high temperature end 6 in the magnetic refrigeration device of this embodiment. As can be seen from FIG. 6, when a predetermined time elapses, a temperature difference is gradually generated between the low temperature end 5 and the high temperature end 6 due to the refrigerant transfer cycle by the magnetic field ON-OF, and heat separation occurs.

  The magnetic circuit 2 uses an NdFeB magnet, an SmCo magnet, a ferrite magnet, or the like. The magnetic circuit 2 is preferably an efficient closed magnetic circuit using a magnetic yoke. Furthermore, a Halbach magnetic circuit may be used that generates a large magnetic field having a structure in which the easy magnetization axis of the magnet circulates in the direction of the magnetic flux.

  The magnetic material 1 is a material that exhibits a magnetocaloric effect, and a Gd (gadolinium) sphere can be used as described above. The sphere size can be, for example, in the range of 0.1 mm diameter to 2 mm diameter, or the particle diameter (major axis) is 0.1 mm or more and 2 mm or less, and 80 wt% or more of the particles have an aspect ratio of 2 or less. It can be. By setting such a size, it is possible to optimize the pressure loss and heat exchange efficiency associated with the refrigerant movement. That is, the heat exchange rate can be increased by exchanging heat with the refrigerant by increasing the specific surface area of the magnetic material 1, and the pressure loss of the refrigerant due to the decrease in the particle diameter can be suppressed to achieve the above optimization. be able to.

  In addition, the preferable particle diameter of the magnetic material 1 shall be about 0.3-0.9 mm.

The magnetic material 1 may be a magnetic material such as a Gd compound, a Ni ₂ MnGa alloy, a GdGeSi compound, a LaFe ₁₃ compound, or a LaFe ₁₃ H compound in which various elements are mixed. Gd alone has a Curie temperature to 294K, and the amount of change in magnetic entropy is maximized, but the amount of change in magnetic entropy is reduced from 294K to a low temperature or a high temperature, and refrigeration efficiency is reduced. Therefore, the refrigeration efficiency can be increased even in a wide temperature range by adopting a hybrid structure using magnetic materials having different Curie temperatures. Therefore, it is preferable to use a plurality of magnetic materials in this magnetic refrigeration technique.

The magnetic fluid (refrigerant) 3 is generally made of an oxide magnetic material. For example, the surface of particles of 10 nm to several 100 nm such as magnetite and ferrite are covered with surfactant molecules, and oil-based, water-based, organic solvents are used. Suspended in a system or fluorine system. As the temperature-sensitive magnetic fluid, an M-Zn ferrite material having a large magnetization temperature change is used among oxide magnetic materials. For example, in the case of Ni _1-z Zn _z Fe ₂ O ₄ or Mn _1-Z Zn _z Fe ₂ O ₄ , the Curie temperature can be lowered by increasing z. In the present magnetic refrigeration device, it is preferable to control the Curie temperature according to the operating temperature range.

  The magnetic fluid (refrigerant) 3 is preferably a temperature-sensitive magnetic fluid. In this case, a change in magnetization due to the temperature characteristics of the temperature-sensitive magnetic fluid occurs due to a temperature change of the magnetic material itself accompanying the magnetic field ON-OFF cycle, and the magnitude of the generated magnetic torque changes. Here, a change in the magnitude of the magnetic torque can cause a delay in refrigerant movement when the magnetic field is turned on and off.

  For example, in FIG. 2, when the magnetic circuit 2 fixed to the linear drive actuator 11 moves in the direction of the magnetic material 1, the magnetic fluid (refrigerant) 3 moves by receiving magnetic torque due to the magnetic field of the magnetic circuit 2. At the same time, the magnetic material 1 generates heat due to the magnetocaloric effect, the temperature of the (magnetic fluid) refrigerant 3 increases, the magnetic torque decreases due to the temperature characteristics of the temperature-sensitive magnetic fluid, and is slower than the moving speed of the linear drive actuator 11. Become. This delay time is an indispensable parameter for efficiently performing heat separation between the high temperature portion and the low temperature portion and realizing a highly efficient magnetic refrigeration device.

  Similarly, in FIG. 3, when the magnetic circuit 2 fixed to the linear drive actuator 11 moves in a direction away from the magnetic material 1, the magnetic material 1 and the magnetic circuit 2 are separated and the magnetic field is removed (magnetic field OFF). It cools by the magnetocaloric effect, and the temperature of the magnetic fluid (refrigerant) 3 also decreases. The temperature-sensitive magnetic fluid of the magnetic fluid (refrigerant) 3 moves by receiving the magnetic torque generated by the magnetic field of the magnetic circuit 2, and at the same time, the magnetic torque increases due to the temperature characteristics of the temperature-sensitive magnetic fluid, and the moving speed increases. However, since the magnetic field sensitive on / off valve 8 is closed, the magnetic fluid (refrigerant) 3 stays without moving, and when the magnetic field of the magnetic circuit 2 exceeds the threshold of the magnetic field sensitive on / off valve 8. It opens, the magnetic fluid (refrigerant) 3 moves, and the cold end 5 can store cold heat. In this way, a delay time can be provided for magnetic field removal and refrigerant movement.

  In the AMR type refrigeration cycle, the steps of magnetic field ON → refrigerant movement → magnetic field OFF → refrigerant movement are basic cycles, and if the magnetic field ON (OFF) and the refrigerant movement are performed simultaneously without any delay, a temperature difference occurs. It becomes difficult. In contrast, by using the temperature-sensitive magnetic fluid as described above, a delay can be formed between the magnetic field ON (OFF) and the refrigerant movement, and a highly efficient magnetic refrigeration device can be realized.

  FIG. 7 is a graph showing the temperature dependence of magnetization of an Mn—Zn temperature-sensitive magnetic fluid which is an example of the above-described temperature-sensitive magnetic fluid. As shown in FIG. 7, in such a temperature-sensitive magnetic fluid, it can be seen that the magnetization decreases as the temperature rises. Therefore, by utilizing such a property, it is possible to cause a delay in refrigerant movement when the magnetic field is turned on and off as described above.

  The magnetic field sensitive open / close valve 8 is composed of a spring and a sealing member for airtightness, a flow path, and a magnetic body, and opens and closes the flow path with an arbitrary balance between the magnetic force attracted by the magnetic body by the magnetic field and the spring force. Is. The linear movement type on-off valve 9 includes a spring, a sealing member for airtightness, a flow path, and a push rod, and moves the push rod to open and close the flow passage simultaneously with pushing the spring. The opening / closing timing can be delayed by arbitrarily setting the spring force and the deformation amount.

  The present invention has been described in detail based on the above specific examples. However, the present invention is not limited to the above specific examples, and various modifications and changes can be made without departing from the scope of the present invention.

  For example, in the above embodiment, the magnetic fluid (refrigerant) 3 is moved using not only the magnetic torque (magnetic attractive force) from the magnetic circuit 2 but also the pressure using the on-off valves 8 and 9. However, the use of the pressure is not an essential constituent element in the present invention, and can be appropriately deleted.

  The magnetic refrigeration device and the magnetic refrigeration method of the present invention may be applied to a refrigeration system such as a household refrigeration refrigerator and air conditioner, an industrial refrigeration refrigerator, a large-sized refrigerated refrigerator, a liquefied gas storage / transport refrigerator. Although the refrigeration capacity and the control temperature range differ depending on the application location, the refrigeration capacity can be varied depending on the amount of magnetic material used. Furthermore, the operating temperature range can be adjusted to a specific temperature range by controlling the material of the magnetic material. Further, the present invention can be applied to an air conditioning system such as a home air conditioner or an industrial air conditioner that uses the exhaust heat of the magnetic refrigeration device as heating. You may apply to the plant using both cooling and heat_generation | fever.

It is a basic composition figure concerning an example of the magnetic refrigeration device of the present invention. It is a figure which shows the drive system figure (at the time of a magnetic field application) of the said magnetic refrigeration device. It is a figure which shows the drive system figure (at the time of magnetic field removal) of the said magnetic refrigeration device. It is a block diagram which shows the modification of the magnetic refrigeration device shown in FIG. Similarly, it is a block diagram which shows the modification of the magnetic refrigeration device shown in FIG. It is a graph which shows the time dependence of the temperature change of the low temperature end and high temperature end in the said magnetic refrigeration device. It is a graph which shows the temperature dependence of magnetization of a Mn-Zn type thermosensitive magnetic fluid.

Explanation of symbols

1 ... Magnetic material (magnetic material)
2. Magnetic circuit 3. Magnetic fluid (refrigerant)
DESCRIPTION OF SYMBOLS 4 ... Separator 5 ... Low temperature end 6 ... High temperature end 7 ... Container 8 ... Magnetic field sensitive on-off valve 9 ... Linear movement type on-off valve 10 ... Piston 11 ... Linear drive actuator 12 ... Spring apparatus

Claims (6)

A magnetic material having a magnetocaloric effect;
A magnetic fluid disposed in contact with the magnetic body;
A magnetic field applying means for applying a magnetic field to the magnetic body;
Magnetic field application removing means that repeats application and removal of the magnetic field to and from the magnetic body by reciprocating the magnetic field application means in a predetermined direction,
The magnetic fluid is heated and cooled by heat absorption and heat generation of the magnetic body resulting from application and removal of the magnetic field, and is moved by a magnetic attraction force resulting from movement of the magnetic field application means, whereby the magnetic body A magnetic refrigeration device, characterized in that a high-temperature part and a low-temperature part are generated at both ends of the magnetic refrigeration device.   The magnetic refrigeration device according to claim 1, wherein the magnetic fluid is a temperature-sensitive magnetic fluid.   The magnetic refrigeration device according to claim 1, wherein the magnetic field generation unit is a permanent magnet circuit.   The magnetism according to any one of claims 1 to 3, further comprising a valve and a valve opening / closing mechanism for moving the magnetic fluid in a length direction of the magnetic body using a pressure difference. Refrigeration device.   5. The magnetic refrigeration device according to claim 4, wherein the valve opening / closing mechanism is configured to open and close the valve in synchronization with driving of the magnetic field application removing unit.   6. The magnetic refrigeration device according to claim 5, wherein the magnetic field application removing means includes a spring member, and the valve is opened and closed with a mechanical delay accompanying expansion and contraction of the spring member.

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