Abstract:
Magnetic refrigerating device improves refrigerating capacity and efficiency by improving the heat exchanging method between a magnetic material and a heat exchanging fluid and devising a magnetic field applying method. The magnetic refrigerating device comprises: a cylindrical active magnetic regenerator (AMR) bed accommodating refrigerant therein; two magnetic materials disposed in the AMR bed in the axial direction, configured to be movable in the axial direction of the AMR bed, and made of material having a magnetocaloric effect; at least two permanent magnets positioned to face the two magnetic materials; a rotary shaft positioned between the two magnetic materials in the AMR bed and positioned between the at least two permanent magnets; and a magnetic rotary movement unit that rotationally moves the permanent magnets about the rotary shaft and that repeatedly moves the permanent magnets and the two magnetic materials closer together and farther apart in association with the rotational movement.

Description:
TECHNICAL FIELD 
       [0001]    The present invention relates to magnetic refrigerating devices suitable for use in air conditioners, car air conditioners, refrigerators, and other devices for heating and cooling in buildings and air conditioning in rooms, particularly to magnetic refrigerating devices using a refrigerant permitted for use in refrigerant substitutes for chlorofluorocarbon and fluorine-based greenhouse effect gases which are effective for protection of the ozone layer of the earth&#39;s atmosphere. 
       BACKGROUND ART 
       [0002]    In Japan, heating and cooling systems currently use refrigerants which are substitutes for chlorofluorocarbon, such as HFC-134a (CH 2 F—CF 3 ), in order to stop serious destruction of the ozone layer due to chlorofluorocarbon. However, since these substitutes for chlorofluorocarbon give greenhouse effect 1300 times greater than that by CO 2 , which is defined as a greenhouse effect gas, the leakage of the currently used refrigerants to the global environment have a profound effect thereon. Hence, in EU, where hydrofluorocarbon (HFC), perfluorocarbon (PFC), and sulfur hexafluoride (SF 6 ) in the Kyoto Protocol are called “F gases”, the EU car air conditioner refrigerant directive has already banned HFC-134a for use in new-model cars. Likewise, North America is considering future prohibition of this substance (see Non Patent Literatures 1 and 2). 
         [0003]    Meanwhile, magnetic refrigeration systems which do not use substitutes for chlorofluorocarbon have attracted attention as heating and cooling systems. Magnetic refrigeration systems, which do not use substitutes for chlorofluorocarbon, are expected to contribute to protection of the ozone layer of the earth&#39;s atmosphere and restrain global warming due to greenhouse effect gases. 
         [0004]    In a magnetic refrigeration system here, a magnetocaloric effect given by a magnetic material is effectively propagated by a heat exchanging fluid to drive a predetermined refrigeration cycle, thereby providing a range of refrigerant temperature and refrigerating capacity. This is typically called an active magnetic regenerator (AMR) refrigeration method and is widely recognized as an essential method at high temperatures, particularly for magnetic refrigeration at room temperature (see Patent Literatures 1 to 3). 
         [0005]    As shown in  FIG. 1 , a known AMR includes a bed  10  which is, for example, a cylinder filled with a granulated magnetic material  12  and a refrigerant  11  acting as a heat exchanging fluid (water or ethylene glycol) introduced thereinto (the bed is hereinafter referred to as “AMR bed”). Pistons  14   a  and  14   b  are provided at both ends of the AMR bed  10  in order to drive the refrigerant  11 . These two pistons  14   a  and  14   b  move in the direction of the arrow C to make a flow of the refrigerant  11  in the magnetic material  12 . One end of the AMR bed  10  is at a low temperature, and the other is at a high temperature. 
         [0006]    As shown in  FIG. 2 , in a typical AMR, a permanent magnet  24 , for example, gives a magnetic field to a magnetic material  22  held in an AMR bed  20 , and pistons (not shown in the drawing) at both ends of the bed, for example, generate a flow of the heat exchanging fluid. 
         [0007]    To be specific, in the initial state, the magnetic material  22  is positioned in the middle of the AMR bed  20  ( FIG. 2 , (A)). The temperature in the magnetic material  22  is uniform. In the next state, magnetic field generating devices  24  outside the AMR bed  10  apply a magnetic field to the magnetic material  22  in the AMR bed  20  ( FIG. 2 , (B)). The temperature in the magnetic material  22  is uniform but higher than in the initial state. In the next state, the magnetic material  22  moves in the AMR bed  20  in the direction of the arrow and reaches one end of the AMR bed  20  at a low temperature ( FIG. 2(C) ). Since heat exchange occurs between a refrigerant  21  and the magnetic material  22 , a temperature gradient occurs in the magnetic material  22 , so that, in the drawing, the right end is at the lowest temperature and the left end is at the highest temperature. 
         [0008]    The magnetic field generating devices  24  are then demagnetized ( FIG. 2 , (D)). The temperature in the magnetic material  22  uniformly decreases while the temperature gradient generated in the step shown in  FIG. 2 , (C) is held. Subsequently, the magnetic material  22  moves in the AMR bed  20  in the opposite direction indicated by the arrow by the aid of the resilience given by a spring or the like and reaches the other end of the AMR bed  20  at a high temperature ( FIG. 2 , (E)). The movement of the magnetic material  22  generates heat exchange between the refrigerant  21  and the magnetic material  22 , further increasing the temperature gradient. Repetition of the process from  FIG. 2 , (B) to  FIG. 2 , (E) generates such a temperature gradient in the AMR bed  20  that the right end is at the lowest temperature and the left end is at the highest temperature. Providing heat exchangers at both ends produces a refrigerating effect. 
         [0009]    When the heat exchanging fluid is caused to flow in the magnetic material  22  in sync with the reciprocating motion of the magnetic material  22  along the axis and the refrigeration cycle is driven in the above-described manner, a temperature difference is generated between both ends of the AMR. A rotation AMR, in which an AMR bed is disposed on part of a circular plate and an AMR cycle is operated using a rotating magnetic material or magnetic field, is known to give an equivalent effect to that given by a reciprocation type. 
         [0010]    In another typical AMR shown in  FIG. 3 , the magnetic material  12  in the AMR bed  10  is driven by a piston  14   c  in the direction of the arrow D to cause the heat exchanging fluid  11  to flow in the magnetic material. This structure also gives an equivalent effect to that given by the device in  FIG. 2 . 
         [0011]    However, the conventional AMR systems have the following problems:
   (i) A mechanism for driving the magnetic material and the heat exchanging fluid is required, which requires high energy input;   (ii) A rotation AMR needs the switching of the high- and low-heat exchanging fluids, causing a heat loss due to the mixture of the fluids during the switching, and   (iii) This complex driving mechanism hinders an increase in the frequency of the refrigeration cycle.   
 
       CITATION LIST 
     Patent Literature 
       [0000]    
       
         PATENT LITERATURE 1: JP-A-2012-37112 
         PATENT LITERATURE2: U.S. Pat. No. 5,743,095 
         PATENT LITERATURE3: U.S. Pat. No. 6,502,404 
       
     
       Non Patent Literature 
       [0000]    
       
         NON PATENT LITERATURE 1: EU niokeru F gasu kisei no doukou to gyokai no taio ni tsuite (Movement and counteraction of the EU industry for F-gas control), Feb. 1, 2013, Japan Association of Refrigeration and Air-Conditioning Contractors, Susumu Ishii, http://www.kikonet.org/event/doc/130201-4.pdf 
         NON PATENT LITERATURE 2: Oubei deno kah-eakon reibai kisei doukou to kokunai kaisei furon hou eno taioukentou (Movement of car air conditioner refrigerant control in Europe and America and discussion of action to the revised CFC control law in Japan), Apr. 24, 2014, Japan Automobile Manufacturers Association, Inc., car air conditioner refrigerant WG, http://www.meti.go.jp/committee/sankoushin/seizou/kagaku/freon_wg2/pdf/004_02_01.pdf 
       
     
       SUMMARY OF INVENTION 
     Technical Problem 
       [0020]    An object of the present invention is to provide a magnetic refrigerating device using an improved method for heat exchange between a magnetic material and a heat exchanging fluid and a devised method for magnetic field application, thereby increasing refrigerating capacity and refrigerating efficiency. 
       Solution to Problem 
       [0021]    As shown in  FIG. 4 , for example, a magnetic refrigerating device of the invention includes: a cylindrical AMR bed  30  that contains refrigerants  31   a  and  31   b;  two magnetic materials  32   a  and  32   b  arranged in a direction of an axis of the AMR bed  30 , the magnetic materials being movable in the direction of the axis of the AMR bed  30  and made of magnetocaloric effect materials; at least two permanent magnets  34   a   1 ,  34   a   2 ,  34   b   1 , and  34   b   2  facing the two magnetic materials in the AMR bed  30 ; a rotary shaft  35  between the two magnetic materials in the AMR bed  30  and between the at least two permanent magnets; and a rotator (not shown in the drawing) that rotates the permanent magnets or the AMR bed  30  about the rotary shaft  35  such that the permanent magnets and the two magnetic materials repeatedly get close to and away from each other due to the rotation, wherein heat exchange occurs between the magnetic materials and the refrigerants in the AMR bed  30  and generates a temperature difference in the AMR bed. 
         [0022]    In a magnetic refrigerating device of the invention, it is preferable that the magnet rotator includes two magnet-mounting plates positioned above and below the AMR bed  30  so as to face each other, the two magnet-mounting plates each including at least two permanent magnets facing the two magnetic materials. 
         [0023]    A magnetic refrigerating device of the invention preferably further includes a magnetic material reciprocating unit  36  that causes the two magnetic materials to reciprocate in the direction of the axis such that when one of the magnetic materials moves toward an outside in the direction of the axis of the AMR bed, the other magnetic material also moves toward the outside. 
         [0024]    A magnetic refrigerating device of the invention preferably further includes high-temperature-side heat exchangers  40   a  and  40   b  at both ends of the AMR bed  30 ; and low-temperature-side heat exchangers  38   a  and  38   b  adjacent to the rotary shaft of the AMR bed  30 . 
         [0025]    In a magnetic refrigerating device of the invention, it is preferable that the AMR bed includes a plurality of AMR beds  30  arranged in the same layer having the rotary shaft  35  as a center, two magnet-mounting plates are included above and below the layer in which the plurality of AMR beds is arranged, the two magnet-mounting plates each including at least two permanent magnets facing the AMR beds  30 , the number of the permanent magnets is two or more and is less than the doubled number of the arranged AMR beds  30 . 
         [0026]    A magnetic refrigerating device of the invention includes: a cylindrical AMR bed that contains refrigerants; two magnetic materials arranged in a direction of an axis of the AMR bed, the magnetic materials being movable in the direction of the axis of the AMR bed and made of magnetocaloric effect materials; a magnetic material reciprocating unit that causes the two magnetic materials to reciprocate in the direction of the axis such that when one of the magnetic materials moves toward an outside in the direction of the axis of the AMR bed, the other magnetic material also moves toward the outside; and a magnetic field applying-removing mechanism that applies and removes a magnetic field to generate a magnetic force and drives the magnetic materials by the generated magnetic force, wherein heat exchange occurs between the magnetic materials and the refrigerants in the AMR bed and generates a temperature difference in the AMR bed. 
         [0027]    In a magnetic refrigerating device of the invention, it is preferable that the magnetic field applying-removing mechanism includes at least two permanent magnets facing the two magnetic materials in the AMR bed. 
         [0028]    In a magnetic refrigerating device of the invention, it is preferable that the magnetic material reciprocating unit is an elastic material provided between the two magnetic materials. 
         [0029]    In a magnetic refrigerating device of the invention, it is preferable that the magnetic material reciprocating unit is an actuator that is provided between the two magnetic materials and expands and contracts in the direction of the axis. 
         [0030]    As shown in  FIGS. 9 , (A) and (B), for example, a magnetic refrigerating device of the invention includes: first and second cylindrical AMR beds  91  and  92  each containing refrigerants, the AMR beds  91  and  92  being joined at the center in the axis direction such that they intersect and the refrigerants are movable between the AMR beds  91  and  92  via the joint; two magnetic materials that are arranged in each of the AMR beds  91  and  92  in a direction of the axis so as to sandwich the joint, the magnetic materials being made of magnetocaloric effect materials; driving devices disposed at both ends of each of the AMR beds  91  and  92 , the driving devices expanding and contracting for compression and suction while keeping the volumes of the refrigerants at fixed levels; low-temperature-side heat exchangers disposed at the joint; high-temperature-side heat exchangers disposed at both ends of the AMR beds  91  and  92 ; at least two permanent magnets facing the respective two magnetic materials in the AMR beds  91  and  92 ; a rotary shaft that is vertical to the AMR beds  91  and  92  provided at the joint; and a rotator that rotates the permanent magnets or the AMR beds  91  and  92  about the rotary shaft such that the permanent magnets and the magnetic materials repeatedly get close to and away from each other due to the rotation, wherein when the AMR bed  91  is close to the permanent magnets, the driving devices at both ends of the AMR bed  92  performs compression and the driving devices at both ends of the AMR bed  91  performs suction at the same time, and when the AMR bed  92  is close to the permanent magnets, the driving devices at both ends of the AMR bed  91  performs compression and the driving devices at both ends of the AMR bed  92  performs suction at the same time; through this operation, heat exchange occurs between the magnetic materials and the refrigerants when the refrigerants move in the AMR beds, thus generating a temperature difference between the joint of the AMR beds and each of both ends; and the low-temperature-side heat exchangers and the high-temperature-side heat exchangers respectively take absorbed heat and generated heat outside. 
         [0031]    In a magnetic refrigerating device of the invention, it is preferable that the rotator includes two magnet-mounting plates positioned above and below the first or second AMR bed so as to face each other, the two magnet-mounting plates each including at least two permanent magnets facing the two magnetic materials. 
         [0032]    In a magnetic refrigerating device of the invention, it is preferable that the driving devices at both ends of the first or second AMR bed each correspond to a piston in contact with the refrigerant and an actuator that expands and contracts the piston in the direction of the axis, or the resilience of a spring. 
       Advantageous Effects of Invention 
       [0033]    A magnetic refrigerating device of the invention provides the following effects:
   1) An AMR cycle consisting of two magnetic materials can be driven by one-time magnetic field control;   2) Each magnetic material is driven by a magnetic force and the resilience of the elastic material joining the magnetic materials, eliminating a need for an external mechanism for driving the magnetic materials;   3) The heat exchanging fluid is stopped in the AMR bed with respect to the magnetic materials and does not need to be driven by an external factor, thereby simplifying the structure; and   4) Rotating a component on which an AMR bed or permanent magnets are mounted easily increases the cycle rate.   
 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0038]      FIG. 1  is a structural diagram of a known reciprocating AMR; 
           [0039]      FIG. 2  is a diagram for explaining the operation of an AMR having the structure shown in  FIG. 1 ; 
           [0040]      FIG. 3  is a structural diagram of another known typical AMR; 
           [0041]      FIG. 4  shows the main structure of a horizontally opposed-type AMR according to a first embodiment of the invention; 
           [0042]      FIG. 5  shows the main structure of a device consisting of two horizontally opposed-type AMRs combined according to a second embodiment of the invention; 
           [0043]      FIG. 6  shows the main structure of a device consisting of four horizontally opposed-type AMRs combined according to a third embodiment of the invention, in which AMR beds rotate; 
           [0044]      FIG. 7  shows the main structure of a device consisting of four horizontally opposed-type AMRs combined according to a modification of the third embodiment of the invention, in which permanent magnets rotate; 
           [0045]      FIG. 8  shows the main structure of a device consisting of two horizontally opposed-type AMRs stacked according to a fourth embodiment of the invention; and 
           [0046]      FIG. 9  shows the main structure of a device consisting of two horizontally opposed-type AMRs stacked according to a fifth embodiment of the invention, in which the refrigerant moves, in which  FIG. 9 , (A) shows a state where the permanent magnets are adjacent to one AMR bed and  FIG. 9 , (B) shows the permanent magnets are adjacent to the other AMR bed. 
       
    
    
     DESCRIPTION OF EMBODIMENTS 
       [0047]    Embodiments of the present invention will now be described in detail with reference to the drawings. 
         [0048]      FIG. 4  is a structural cross-sectional view of a horizontally opposed-type two-cylinder AMR according to an embodiment of the present invention, in which  FIG. 4 , (A) shows an excited state and  FIG. 4 , (B) shows a demagnetized state. In the horizontally opposed-type two-cylinder AMR, the movements of magnetic materials  32   a  and  32   b,  corresponding to the two cylinders, disposed respectively on the right and left sides are opposite on the same axis, and the magnetic materials cancel out the primary vibration and the secondary vibration each other. This also cancels out precession (couple vibration) due to a couple of force. The horizontally opposed-type two-cylinder AMR includes a combination of series-connected cylindrical magnetic materials which are disposed respectively on the right and left sides and 180° out of phase with each other. In other words, the horizontally opposed-type two-cylinder AMR has excellent vibration characteristics which balance the primary vibration, the secondary vibration, and the couple vibration like a series-connected two-cylinder AMR, which has a large total length, and is an ideal AMR which is compact, lightweight, and low vibration. 
         [0049]    To be specific, in  FIG. 4 , the AMR bed  30  is filled with the magnetic materials  32   a  and  32   b,  which are disposed respectively on the right and left sides, and refrigerants  31   a  and  31   b  and made of, for example, a nonmagnetic material. Examples of the nonmagnetic material include metals, such as aluminum, and resins, such as plastic. The refrigerants  31   a  and  31   b  transport heat generated by the magnetocaloric effect and are, for example, an antifreeze, such as water or an ethylene glycol solution. In the AMR bed  30 , chambers containing the magnetic materials are defined by low-temperature-side heat exchangers  38   a  and  38   b  positioned between the magnetic materials  32   a  and  32   b  on the right and left sides. 
         [0050]    The magnetic materials  32   a  and  32   b  are, for example, magnetic beds charged with magnetic particles providing the magnetocaloric effect, and the movements of the magnetic materials disposed respectively on the right and left sides are opposite on the same axis. The magnetic particles are of, for example, gadolinium (Gd). The magnetic materials  32   a  and  32   b  are movable in the AMR bed  30  and alternate between a state where they get closer to each other ( FIG. 4 , (A)) and a state where they get away from each other ( FIG. 4 , (B)). As shown in  FIGS. 4 , (A) and (B), the magnetic materials  32   a  and  32   b  move in the AMR bed  30  in the directions of the white arrows A and B, respectively. When close to permanent magnets  34   a   1 ,  34   a   2 ,  34   b   1 , and  34   b   2 , the magnetic materials  32   a  and  32   b  are adjacent to a rotary shaft  35 . When away from the permanent magnets  34   a   1 ,  34   a   2 ,  34   b   1 , and  34   b   2 , the magnetic materials  32   a  and  32   b  are adjacent to end portions  40   a  and  40   b.  The end portions of the magnetic materials  32   a  and  32   b  have a mesh partition plate that allows the magnetic particles to be held inside the bed and the refrigerants  31   a  and  31   b  and the magnetic particles to move relatively to each other. The magnetic beds corresponding to the magnetic materials  32   a  and  32   b  are made of, for example, a nonmagnetic material. Examples of the nonmagnetic material include metals, such as aluminum, and resins, such as plastic. 
         [0051]    The permanent magnets  34   a   1 ,  34   a   2 ,  34   b   1 , and  34   b   2 , which are included in a magnetic field applying-removing mechanism, are disposed outside the AMR bed  30  and the permanent magnets  34   a   1 ,  34   a   2 ,  34   b   1 , and  34   b   2  are provided in pairs for the respective magnetic materials  32   a  and  32   b  on the right and left sides so as to sandwich them, thereby forming a magnetic circuit. The permanent magnets  34   a   1  and  34   b   1  are disposed, for example, on a circular plate (not shown in the drawing) above the AMR bed  30 . The permanent magnets  34   a   2  and  34   b   2  are disposed on a circular plate (not shown in the drawing) below the AMR bed  30 . A rotation mechanism, not shown in the drawing, rotates the AMR bed  30  about the rotary shaft  35  and alternately generates the excited state and the demagnetized state. In this case, the positions of the two circular plates on which the permanent magnets  34   a   1 ,  34   a   2 ,  34   b   1 , and  34   b   2  are placed are fixed. The rotary shaft  35  is coaxial with the AMR bed  30  and the pair of circular plates. 
         [0052]    It should be noted that the rotation mechanism may rotate the pair of circular plates on which the permanent magnets  34   a   1 ,  34   a   2 ,  34   b   1 , and  34   b   2  are placed while fixing the AMR bed  30  and may rotate the AMR bed  30  in the direction opposite to the direction in which the pair of circular plates is rotated. Moreover, the mechanism may move the permanent magnets  34   a   1 ,  34   a   2 ,  34   b   1 , and  34   b   2  in the thickness direction of the AMR bed  30  and alternately generate the excited state and the demagnetized state. The movements of the permanent magnets  34   a   1 ,  34   a   2 ,  34   b   1 , and  34   b   2  allow a magnetic field to be applied to or removed from the magnetic materials  32   a  and  32   b.  This also generates a magnetic torque, acting on the magnetic materials  32   a  and  32   b,  in the same direction as the direction of the movements of the permanent magnets  34   a   1 ,  34   a   2 ,  34   b   1 , and  34   b   2  and the magnetic materials  32   a  and  32   b.    
         [0053]    A magnetic material reciprocating unit  36  is provided between the low-temperature-side heat exchangers  38   a  and  38   b  on the right and left sides. The drive force of the magnetic material reciprocating unit  36  and the magnetic torque given by the permanent magnets  34   a   1 ,  34   a   2 ,  34   b   1 , and  34   b   2  cause the magnetic materials  32   a  and  32   b  to be opposed on the same axis and expand and contract in the axis direction. The magnetic material reciprocating unit  36  may be a driving device, such as an actuator, or an elastic material, such as a coil spring (spring coil). When the magnetic material reciprocating unit  36  is an elastic material, the resilience (elastic force) of the spring works as a drive force. 
         [0054]    The low-temperature-side heat exchangers  38   a  and  38   b  and high-temperature-side heat exchangers  40   a  and  40   b  are made of, for example, Cu (copper), which has high thermal conductivity, and may be made of aluminum or a stainless steel fin or a stainless steel mesh instead. A magnetic refrigeration cycle propagates hot heat and cold heat generated in the refrigerants  31   a  and  31   b  to the low-temperature-side heat exchangers  38   a  and  38   b  and the high-temperature-side heat exchangers  40   a  and  40   b,  respectively. As described later, in a magnetic refrigerating device to which the magnetic refrigerating device according to this embodiment is applied, hot heat is transported from the low-temperature-side heat exchangers  38   a  and  38   b  to a hot heat outlet, and cold heat is transported from the high-temperature-side heat exchangers  40   a  and  40   b  to a cooling unit. 
         [0055]    The behavior of a device having this structure will now be described. 
         [0056]    Two magnetic materials  32   a  and  32   b  joined by the magnetic material reciprocating unit  36 , such as a spring, are disposed in the AMR bed  30 . The AMR bed  30  is charged with the heat exchange refrigerants  31   a  and  31   b,  such as water. Two magnetic materials (magnetocaloric materials)  32   a  and  32   b  are provided symmetrically. The end portions  38   a  and  38   b  of the magnetic materials  32   a  and  32   b  on the rotary shaft side are joined by an elastic material, such as a spring, serving as the magnetic material reciprocating unit  36 . 
         [0057]    The AMR bed  30  is rotated with respect to the fixed external magnets  34   a   1 ,  34   a   2 ,  34   b   1 , and  34   b   2  so that magnetic fields are applied to and removed from the two magnetic materials  32   a  and  32   b.  When the magnetic materials are provided in appropriate positions with respect to the two magnetic materials  32   a  and  32   b,  the rotation of the AMR bed  30  generates a magnetic force that allows the two magnetic materials  32   a  and  32   b  to move in the magnetic bed  30  symmetrically. At this time, heat exchange with the heat exchanging fluids  31   a  and  31   b  in the AMR bed  30  occurs, thereby driving a cycle corresponding to the AMR refrigeration process which has been described with reference to  FIG. 2 . Therefore, in the horizontally opposed-type two-cylinder AMR having the structure shown in  FIG. 4 , low-temperature cold occurs in the portions  38   a  and  38   b  positioned in the center of the rotation, and high-temperature exhaust heat occurs in the end portions  40   a  and  40   b.    
         [0058]    Further details of heat transfer in the magnetic refrigerating device will now be described. 
         [0059]    Upon application of magnetic fields by the magnets  34   a   1 ,  34   a   2 ,  34   b   1 , and  34   b   2  positioned relatively close to the rotary shaft, the two magnetic materials  32   a  and  32   b  are attracted toward the rotary shafts  38   a  and  38   b,  respectively, by the magnetic force. At this time, the magnetic material for the magnetic materials  32   a  and  32   b  generates heat due to the magnetocaloric effect and exchange heat with the refrigerant due to the movement of the magnetic material, so that a relatively high-temperature refrigerant stagnates in the end portions  40   a  and  40   b  of the AMR bed  30 . 
         [0060]    When further rotation gets the AMR bed  30  out of the magnetic field, the resilience of the spring  36  causes the magnetic material in the two magnetic materials  32   a  and  32   b  to move to the end portions  40   a  and  40   b  while absorbing heat. In this process, the heat exchange with the refrigerant occurs, generating coldness in the central portions around the rotary shaft  35 . When it is repeated, the temperatures in the central portions of the AMR bed  30  decrease, and the temperatures at the end portions increase. The heat exchangers  38   a  and  38   b , which are disposed in the central portion, receive an external refrigerant from a different system, so that the coldness can be taken to the outside. The heat exchangers  40   a  and  40   b  at both ends are cooled by an external fan or other means, thereby exhausting heat. 
         [0061]    An embodiment of the invention, which uses a horizontally opposed-type two-cylinder AMR, provides the following effects.
   (i) One-time magnetic field control drives magnetic refrigeration cycles in two magnetocaloric effect materials. This generates the refrigerating effect twice as much as that in a conventional single-cylinder AMR.   (ii) Movement of the refrigerants is unnecessary, so that a need of an external pump for driving the refrigerants is eliminated unlike a conventional single-cylinder AMR, thereby dramatically simplifying the device. This reduces a heat loss and increases the rate of the refrigeration cycles.   (iii) Two or more AMR beds are disposed in appropriate positions with respect to the magnets, so that the magnetic torque entering the magnets and the magnetic torque from the magnets cancel out each other, which largely contributes to a reduction in drive force. This means that the refrigerating efficiency is increased.   
 
         [0065]      FIG. 5  is a structural diagram of a second embodiment of the invention, showing the main structure of a device in which two horizontally opposed-type AMRs are combined.  FIG. 5  shows a magnetic refrigerating device in which the horizontally opposed-type two-cylinder AMRs, which are the same as in  FIG. 1  but out of phase, are combined. 
         [0066]    In  FIG. 5 , AMR beds  50 A and  50 B each have two magnetic materials joined by a magnetic material reciprocating unit, such as a spring, and its inner structure is similar to  FIG. 1  and thus is omitted in the drawing. The AMR bed  50 A, which is depicted in a horizontal state in  FIG. 5 , is in a position overlapping permanent magnets  54   a  and  54   b.  The AMR bed  50 B, which is disposed in a position intersecting the AMR bed  50 A, is away from the permanent magnets  54   a  and  54   b.  The rotary shaft  55  is provided along the rotation axis of a pair of circular plates (not shown in the drawing) on which the AMR beds  50 A and  50 B and the magnets  54   a  and  54   b  are mounted. 
         [0067]    Since a magnetic refrigerating device with this structure includes two horizontally opposed-type AMRs combined, the AMR beds  50 A and  50 B pass by the fixed magnets  54   a  and  54   b  when rotating in the direction of the arrow. When they pass by these, the AMR beds  50 A and  50 B cancel out the magnetic forces each other. 
         [0068]      FIG. 6  is a structural diagram of the third embodiment of the invention, showing the main structure in which four horizontally opposed-type AMRs are combined.  FIG. 6 , (A) is a plan view, and  FIG. 6 , (B) is a cross-sectional view along line A-A in  FIG. 6 , (A). Here, four horizontally opposed-type AMRs are combined and cold heat is further transported from low-temperature-side heat exchangers for the AMRs to coolers  68  and  70 . In addition, hot heat is further transported from high-temperature-side heat exchangers for the AMRs to heat outlets  69  and  72 . Rotary shaft central portions  65  and  68  of the AMRs are common components for convenience of heat exchange and drive. When viewed from the rotary shaft central portions of the AMRs, eight single-cylinder AMRs look like hub and spokes. Note that the arrow indicates the direction of the rotation of the AMR bed. 
         [0069]    In  FIG. 6 , AMR beds  60 A,  60 B,  60 C, and  60 D each includes two magnetic materials joined by a magnetic material reciprocating unit, such as a spring, and their inner structures are similar to  FIG. 4  and thus are omitted in the drawing. The AMR bed  60 A, which is depicted in a horizontal state in  FIG. 6 , is in a position overlapping permanent magnets  64 Aa and  64 Ab. The AMR bed  60 B, which is disposed in a position intersecting the AMR bed  60 A, is in a position overlapping permanent magnets  64 Ba and  64 Bb. The AMR beds  60 C and  60 D, which are disposed at  45 ° to the AMR beds  60 A and  60 B, are away from the permanent magnets  64 Aa,  64 Ab,  64 Ba, and  64 Bb. A rotary shaft  65  is provided along the rotation axis of a pair of circular plates (not shown in the drawing) on which the AMR beds  60 A,  60 B,  60 C, and  60 D and the magnets  64 Aa,  64 Ab,  64 Ba, and  64 Bb are mounted. The pair of circular plates each faces the tops or bottoms of the AMR beds  60 A,  60 B,  60 C, and  60 D. 
         [0070]    A low-temperature-side heat exchanger  68  is mounted to the rotary shaft  65  at its center and one ends of the eight single-cylinder AMRs are mounted to the outer periphery of the exchanger. The high-temperature-side heat exchanger  69  has a ring shape having an inner periphery to which the other ends of the eight single-cylinder AMRs are mounted. A cooling-side heat exchanger  70  is used to perform cooling by introducing a refrigerant to the low-temperature-side heat exchanger  68 . A heat-exhausting-side heat exchanger  72  is used to conduct exhaust heat by introducing a refrigerant to the high-temperature-side heat exchanger  69 . 
         [0071]    Since a magnetic refrigerating device with this structure includes four horizontally opposed-type AMRs combined, the AMR beds  60 A,  60 B,  60 C, and  60 D pass by the fixed permanent magnet  64 Aa,  64 Ab,  64 Ba, and  64 Bb when rotating in the direction of the arrow. When they pass by these, the AMR beds  60 A,  60 B,  60 C, and  60 D cancel out the magnetic forces each other. 
         [0072]      FIG. 7  is a structural diagram of a modification of a third embodiment of the invention, showing the main structure in which four horizontally opposed-type AMRs are combined. In  FIG. 7 , the arrow indicates the direction of the rotation of the permanent magnets, and the AMR beds are fixed. In other words, the fixation and rotation relationship between the AMR beds and the permanent magnets is opposite to that in the third embodiment shown in  FIG. 6 . Here, in both of the embodiments in  FIGS. 6 and 7  in which the magnetic materials can reciprocate, rotating the magnets and rotating the AMR beds are different merely in relative movements and result in the same refrigeration cycles to be conducted. These, however, require different structures of the magnetic refrigerating device: one is a type in which the rotary shaft is in cooperation with the magnets (or a structure including the permanent magnets), and the other is a type in which the rotary shaft is in cooperation with the AMR beds. 
         [0073]    According to the third embodiment of the invention in  FIGS. 6 and 7 , a magnetic refrigeration device consisting of four AMR beds can cancel out the magnetic force when passing by the fixed magnets and has two or more AMR beds disposed symmetrically, thereby reducing the drive force. 
         [0074]      FIG. 8  is a structural diagram of a fourth embodiment of the invention, showing the main structure of a device in which two horizontally opposed-type AMRs are stacked. In  FIG. 8 , AMR beds  82  and  83  each include two magnetic materials joined by a magnetic material reciprocating unit, such as a spring, and their inner structures are similar to  FIG. 4  and thus are omitted in the drawing. Low-temperature-side heat exchangers  88  and  89  are provided in the central portions, and high-temperature-side heat exchangers  86  and  87  are provided at both ends. 
         [0075]    The AMR bed  82 , which is depicted upward in  FIG. 8 , is in a position overlapping permanent magnet  84   a   1 ,  84   a   2 ,  84   b   1 , and  84   b   2 . The AMR bed  83 , which is disposed lower than the AMR bed  82 , are away from the permanent magnets  85   a   1 ,  85   a   2 ,  85   b   1 , and  85   b   2 . Rotary shafts  80  and  81  are provided along the rotation axis of a pair of circular plates (not shown in the drawing) on which the AMR beds  82  and  83  or the permanent magnets  84   a   1 ,  84   a   2 ,  84   b   1 ,  84   b   2 ,  85   a   1 ,  85   a   2 ,  85   b   1 , and  85   b   2  are mounted. The rotary shaft  80  and the rotary shaft  81 , which have the same rotation axis, are joined. 
         [0076]    A low-temperature-side heat exchanger  88  is mounted to the rotary shaft  80  at its center and its outer periphery is mounted to the central portion of the AMR bed  82 . A high-temperature-side heat exchanger  86  has, for example, a ring shape having an inner periphery to which both ends of the AMR bed  82  are mounted. A low-temperature-side heat exchanger  89  is mounted to the rotary shaft  81  at its center and its outer periphery is mounted to the central portion of the AMR bed  83 . A high-temperature-side heat exchanger  87  has, for example, a ring shape having an inner periphery to which both ends of the AMR bed  83  are mounted. A cooling-side heat exchanger  100  is used to perform cooling by introducing a refrigerant to the low-temperature-side heat exchangers  88  and  89 . A heat-exhausting-side heat exchanger  102  is used to conduct exhaust heat by introducing a refrigerant to the high-temperature-side heat exchangers  86  and  87 . 
         [0077]    Since a magnetic refrigerating device with this structure includes two horizontally opposed-type AMRs stacked, the AMR beds  82  and  83  pass by the fixed permanent magnets  84   a   1  to  85   b   2  when rotating. Alternatively, the permanent magnets  84   a   1  to  85   b   2  pass by the fixed AMR beds  82  and  83  when rotating. When they pass by these, heat exchange occurs. The fourth embodiment, in which two horizontally opposed-type AMRs are stacked, easily increases the refrigerating capacity. 
         [0078]      FIGS. 9 , (A) and (B) are structural diagrams showing a fifth embodiment of the invention. Two beds  91  and  92  filled with magnetic materials  90  and a heat exchanging fluid are joined in the middle, the heat exchanging fluid is movable between two beds. Here, each magnetic material  90  is fixed to the corresponding bed, and pistons  93  and  94  at both ends of the beds  91  and  92  make the heat exchanging fluid movable in the bed and the magnetic material  90 . The pistons  93  and  94  are driven at opposite phases. When the ends of the pistons  94  at both ends of the bed  92  are pushed, the pistons  93  at both ends of the bed  91  concurrently move toward the outside, thereby keeping the volume of the heat exchanging fluid inside at a fixed level. The pistons are driven by use of the resilience of a spring or a driving device, such as an actuator. 
         [0079]    In this embodiment, the beds  91  and  92  are stopped, and magnets  97  are rotated.  FIG. 9 , (A) indicates a situation where the magnets  97  overlap the magnetic materials  90  in the bed  91 . The magnets  97  magnetize the magnetic materials  90  in the bed  91 , cause the pistons  94  in the bed  92  to move toward the center, and cause the pistons  93  in the bed  91  to move toward the outside at the same time. This makes the heat exchanging fluid flow in the bed  92  in the directions of arrows  95  and move toward both ends of the bed  91  through the joint in the directions of arrows  96 . At this time, coldness generates at the joint and heat generated in the magnetic materials in the bed  91  moves toward both ends of the bed  91 . 
         [0080]      FIG. 9 , (B) shows a situation after the magnets  97  rotated about a drive shaft  99  have moved from the bed  91  to the bed  92 . The pistons are driven at the phrase opposite to that in the situation shown in  FIG. 9 , (A), so that coldness accumulates at the joint in the middle and generated heat accumulates at both ends of the beds  91  and  92  in the same manner. Low-temperature-side heat exchangers are provided at the joint in the middle and high-temperature-side heat exchangers are provided at both ends, allowing absorbed heat and generated heat to be taken outside. This system is characterized in that the magnetic materials are fixed to the beds, the volume of the heat exchanging fluid is kept at a fixed level, the pistons installed in the two beds are driven at the opposite phases, and this driving operation is in sync with the rotation of the magnets. This provides the same results as and similar AMR effects to those of the system for driving the magnetic materials in the previous embodiment. 
         [0081]    It should be noted that the invention should not be limited to the above embodiments, which illustrate magnetic refrigerating devices including various horizontally opposed-type AMRs, and various design modifications can be made without departing from the scope obvious to those skilled in the art and should be interpretatively included in the scope of the invention. 
       INDUSTRIAL APPLICABILITY 
       [0082]    The magnetic refrigerating device of the invention is suitable for use in refrigerating and cooling devices within the range from room temperature to cryogenic temperature. In particular, the magnetic refrigerating device of the invention is suitable for use in air conditioners, refrigerators, freezers, and cryogenic refrigerators, for example. 
       REFERENCE SIGNS LIST 
       [0000]    
       
           10 ,  20 ,  30 : AMR bed 
           11 ,  21 ,  31   a,    31   b : Refrigerant 
           12 ,  22 ,  32   a,    32   b : Magnetic material 
           14   a,    14   b,    14   c : Piston 
           24 ,  34   a   1 ,  34   a   2 ,  34   b   1 ,  34   b   2 ,  54 ,  64 ,  84   a   1 ,  84   a   2 ,  84   b   1 ,  84   b   2 ,  94   a   1 ,  85   a   2 ,  85   b   1 ,  85   b   2 : Magnets 
           35 ,  55 ,  65 ,  80 ,  81 ,  99 : Rotary shaft 
           36 : Magnetic material reciprocating unit 
           50 A,  50 B,  60 A,  60 B,  60 C,  60 D,  82 ,  83 : AMR bed 
           38   a,    38   b,    68 ,  88 ,  89 : Low-temperature-side heat exchanger 
           40   a,    40   b,    69 ,  86 ,  87 : High-temperature-side heat exchanger 
           70 ,  100 : Cooling-side heat exchanger 
           72 ,  102 : Heat-exhausting-side heat exchanger