Patent Publication Number: US-2013232993-A1

Title: Heat exchanger and magnetic refrigeration system

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This is a continuation application of International Application PCT/JP2010/069376, filed on Oct. 29, 2010; the entire contents of which are incorporated herein by reference. 
    
    
     FIELD 
     Embodiments described herein relate generally to a heat exchanger and a magnetic refrigeration system. 
     BACKGROUND 
     Recently, as an environment-conscious and efficient refrigeration technology, the magnetic refrigeration technology using the magnetocaloric effect has been raising expectations and activating research and development. In the magnetic refrigeration technology, a magnetic refrigeration cycle is configured using the magnetocaloric effect to produce a high temperature section and a low temperature section. 
     As one of such magnetic refrigeration technologies, the refrigeration technology called the AMR (active magnetic regenerative refrigeration) technique is proposed. In the AMR technique, the magnetic refrigeration operation using the magnetocaloric effect is performed by a heat exchange component including a magnetocaloric effect material. Simultaneously, the cold heat generated by this magnetic refrigeration operation is stored in that component. 
     The AMR technique can achieve a higher heat exchange efficiency than the gas refrigeration technology using the gas compression-expansion cycle. 
     However, from the viewpoint of energy saving and the like, further improvement in heat exchange efficiency has been desired. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIGS. 1A and 1B  are schematic sectional views for illustrating a heat exchanger according to a first embodiment; 
         FIGS. 2A to 2C  are schematic sectional views for illustrating heat exchangers according to comparative examples; 
         FIGS. 3A to 3C  are schematic sectional views for illustrating the arrangement of heat exchange components; 
         FIGS. 4A to 4E  are schematic sectional views for illustrating the cross-sectional shape in the plane parallel to the xy plane of the heat exchange component; 
         FIGS. 5A and 5B  are schematic views for illustrating the turbulent state occurring in the flow of the heat transport medium  20 ; 
         FIGS. 6A and 6B  are schematic views for illustrating the arrangement configuration of the heat exchange components; 
         FIGS. 7A and 7B  are graphs for illustrating the comparison between the amount of heat exchange of the practical example and the amount of heat exchange of the comparative example; 
         FIGS. 8A to 8D  are schematic views for illustrating a method for arranging the heat exchange components; 
         FIGS. 9A to 9D  are also schematic views for illustrating a method for arranging the heat exchange components; 
         FIGS. 10A and 10B  are also schematic views for illustrating a method for arranging the heat exchange components; 
         FIGS. 11A and 11B  are schematic sectional views for illustrating cases of arranging heat exchange components formed from different magnetocaloric effect materials; 
         FIG. 12  is a schematic configuration view for illustrating a magnetic refrigeration system according to a second embodiment; and 
         FIG. 13  is a schematic line diagram of the magnetic refrigeration system according to the second embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     In general, according to one embodiment, a heat exchanger includes a container, and a plurality of heat exchange components. 
     The container is fed with a heat transport medium. 
     The plurality of heat exchange components is provided with a prescribed spacing inside the container. 
     The plurality of heat exchange components is provided along a flowing direction of the heat transport medium so as not to overlap at least partly as viewed in the flowing direction of the heat transport medium. 
     Embodiments will now be illustrated with reference to the drawings. In the drawings, similar components are labeled with like reference numerals, and the detailed description thereof is omitted appropriately. 
     In the drawings, arrows x, y, and z indicate three directions (axes) orthogonal to each other. The z direction is taken as the direction of magnetic field. 
     The flowing direction of the heat transport medium  20  may be directed in the y direction or the direction opposite to the y direction during the operation of the magnetic refrigeration system. As an example, the case of the heat transport medium  20  flowing in the y direction will be illustrated. 
     First Embodiment  
       FIGS. 1A and 1B  are schematic sectional views for illustrating a heat exchanger according to a first embodiment.  FIGS. 2A to 2C  are schematic sectional views for illustrating heat exchangers according to comparative examples. Here,  FIG. 2A  is a schematic sectional view of a heat exchanger provided with spherical heat exchange components including a magnetocaloric effect material.  FIGS. 2B and 2C  are schematic sectional views of a heat exchanger provided with plate-like heat exchange components including a magnetocaloric effect material. 
       FIGS. 3A to 3C  are schematic sectional views for illustrating the arrangement of heat exchange components. 
     First, heat exchangers according to comparative examples are illustrated. 
       FIG. 2A  is a schematic sectional view for illustrating a heat exchanger according to a first comparative example. 
     As shown in  FIG. 2A , the heat exchanger (ARM bed)  50  includes a container  51 , heat exchange components  52 , and a partition  53 . 
     The container  51  is configured as a tube having a rectangular cross-sectional shape as viewed in the y direction. 
     The heat exchange component  52  has a spherical shape and is configured to include a magnetocaloric effect material such as Gd (gadolinium). The heat exchange components  52  are packed inside the container  51  with a packing ratio of 60% or more. 
     The partition  53  is shaped like a mesh and provided near both end portions of the container  51 . The mesh size of the partition  53  is made smaller than the size of the heat exchange component  52  so as to prevent the heat exchange component  52  from dropping out of the container  51 . The heat exchanger  50  is configured so that a heat transport medium  20  is fed into the container  51  through one partition  53 , and the fed heat transport medium  20  is ejected out of the container  51  through the other partition  53 . The feed and ejection of the heat transport medium  20  to the container  51  from one direction, and the feed and ejection of the heat transport medium  20  to the container  51  from the opposite direction, constitute one magnetic refrigeration cycle. 
     Here, if the particle diameter of the heat exchange component  52  is made small, the heat exchange components  52  can be packed inside the container  51  with a high packing ratio and a large surface area. In this case, as the packing ratio becomes higher, the amount of heat generated by the magnetic refrigeration work becomes larger. As the surface area becomes larger, the generated heat can be passed (heat-exchanged) more efficiently to the heat transport medium  20 . 
     However, in the case where the frequency of the magnetic refrigeration cycle is made higher (the number of magnetic refrigeration cycles per unit time is increased) to increase the refrigeration power, the pressure loss of the heat transport medium  20  is increased with the increase of the frequency. This may decrease the refrigeration performance, or hamper the operation of the magnetic refrigeration system including the heat exchanger  50 . 
     More specifically, in the heat exchanger  50  packed with spherical heat exchange components  52 , in the case where the particle diameter is small, the pressure loss is increased with the increase of the frequency. This may make difficult the operation of the magnetic refrigeration system including the heat exchanger  50 . On the other hand, in the case where the particle diameter is large, the pressure loss can be reduced. However, due to the decrease of the surface area, the heat exchange efficiency decreases and may incur the decrease of the refrigeration performance. 
       FIGS. 2B and 2C  are schematic sectional views for illustrating a heat exchanger according to a second comparative example. 
     As shown in  FIGS. 2B and 2C , the heat exchanger (ARM bed)  60  includes a container  51  and heat exchange components  62 . 
     The heat exchange component  62  has a plate-like shape and is configured to include a magnetocaloric effect material such as Gd (gadolinium). The heat exchange components  62  are provided in a plurality inside the container  51 . The space between the heat exchange components  62  and between the heat exchange component  62  and the inner wall of the container  51  constitutes the channel of the heat transport medium  20 . 
     Thus, the plate-like heat exchange components  62  are provided parallel to the flow of the heat transport medium  20 . This can reduce the pressure loss of the heat transport medium  20 . Accordingly, the frequency of the magnetic refrigeration cycle can be increased. 
     However, the heat transport medium  20  fed into the container  51  flows at high speed in a portion having low flow resistance between the heat exchange components  62  and between the heat exchange component  62  and the inner wall of the container  51 . Thus, if the frequency of the magnetic refrigeration cycle is increased, the heat exchange efficiency between the heat exchange component  62  and the heat transport medium  20  is decreased. This may decrease the refrigeration performance. 
     Furthermore, the magnetic refrigeration system based on the AMR technique is operated with a temperature gradient formed between both ends (high temperature end and low temperature end) of the heat exchanger. More specifically, a temperature gradient is formed by the heat storage effect of the heat exchange component including the magnetocaloric effect material. In the state in which the temperature gradient is formed, the operation is performed. Thus, heat generation at the high temperature end and heat absorption at the low temperature end are utilized. Accordingly, it is necessary to produce a large temperature difference between the high temperature end and the low temperature end and to stably maintain the temperature gradient formed between both ends. The temperature gradient formed can be stably maintained by decreasing the thermal conductivity between the portion of the heat exchange component  62  located on the high temperature end side and the portion of the heat exchange component  62  located on the low temperature end side. 
     However, in the plate-like heat exchange component  62 , the portion located on the high temperature end side and the portion located on the low temperature end side are integrated. This results in high thermal conductivity. Next, returning to  FIGS. 1A and 1B  and  FIGS. 3A to 3C , the heat exchanger according to the first embodiment is illustrated. 
     As shown in  FIGS. 1A and 1B , the heat exchanger (ARM bed)  1  includes a container  11  to be fed with a heat transport medium  20 , and heat exchange components  12 . 
     The container  11  can be configured as a tube having a rectangular cross-sectional shape as viewed in the y direction. However, the cross-sectional shape as viewed in the y direction is not limited to a rectangle, but can be appropriately modified. 
     For instance, by using a cylindrical container having a circular cross-sectional shape as viewed in the y direction, the pressure in the container can be isotropically distributed. Furthermore, a cylindrical container is preferable also from the viewpoint of the heat exchange efficiency between the heat exchange component  12  in contact with the container inner wall and the heat transport medium  20 . In the case of a tube having a rectangular cross-sectional shape, the heat exchange efficiency between the heat transport medium  20  and the heat exchange component  12  is made lower at the corners than at the tube center portion. However, a cylindrical container can improve this situation. 
     The heat exchange component  12  is configured to include a magnetocaloric effect material. Examples of the magnetocaloric effect material can include Gd (gadolinium), Gd compounds of Gd (gadolinium) mixed with some elements, intermetallic compounds made of some rare earth elements and transition metal elements, Ni 2 MnGa alloys, GdGeSi compounds, LaFe 13 -based compounds, and LaFe 13 H. However, the magnetocaloric effect material is not limited to those illustrated. Any material developing the magnetocaloric effect can be appropriately selected. 
     The heat exchange components  12  are provided in a plurality with a prescribed spacing inside the container  11 . The heat exchange components  12  are arranged parallel to each other inside the container  11 . The longest side  12   a  of the heat exchange component  12  is directed parallel to the direction of the magnetic field (z direction). One side  12   b  in the plane perpendicular to the longest side  12   a  is directed parallel to the y direction. As illustrated in  FIG. 1A  and  FIGS. 3A to 3C , the plurality of heat exchange components  12  are provided along the flowing direction of the heat transport medium  20  so as not to overlap at least partly as viewed in the flowing direction (y direction) of the heat transport medium  20 . 
     In this description, the flowing direction of the heat transport medium  20  refers to the streamline of the heat transport medium  20  in the container  11 , and not to the feeding direction of the heat transport medium  20  into the container  11 . 
     Here, the streamline is defined as follows. The y-direction center point is denoted by (Y0, x). The y-direction end points (the points in contact with the wall surface of the container  11 ) at the same x position as (Y0, x) are denoted by (Yr, x) and (Y-r, x). The trajectory of the point at which the distance to (Y0, x) and the distance to (Yr, x) are equal is denoted by line L 1 . The trajectory of the point at which the distance to (Y0, x) and the distance to (Y-r, x) are equal is denoted by line L 2 . Then, the streamline is defined as lines L 1  and L 2 . For instance, in the case where the container  11  has a rectangular cross section as shown in  FIGS. 1A and 1B , then L 1  and L 2  are parallel to the x-axis direction. 
     In this case, as illustrated in  FIG. 1A  and  FIGS. 3A to 3C , the heat exchange components  12  can be arranged in a staggered lattice in the plane parallel to the xy plane. However, the embodiment is not limited to the arrangement in a staggered lattice. The arrangement pitch of the heat exchange components  12  may be made different for each column, or the arrangement pitch of the heat exchange components  12  may be changed in one column. 
     Furthermore, as shown in  FIGS. 1A and 3B , the heat exchange components  12  can be arranged so that the dimension d between the heat exchange components  12  in the x direction is related to the dimension a of the heat exchange component  12  in the same direction as d≦a. 
     Furthermore, a plurality of columns having such a dimensional relation can be arranged in the y direction with a gap between the columns. 
     Furthermore, the columns adjacent in the y direction can be configured so that the heat exchange components  12  in the respective columns have a complementary relation to the gap  12   c  between the heat exchange components  12 . More specifically, as viewed in the y direction, the gap  12   c  between the heat exchange components  12  located in the forward column can be obstructed by a heat exchange component  12  located in the backward column. Furthermore, as viewed in the y direction, the gap  12   c  between the heat exchange components  12  located in the backward column can be obstructed by a heat exchange component  12  located in the forward column. 
     That is, the gap  12   c  between the heat exchange components  12  provided on the front side in the flowing direction of the heat transport medium  20  is obstructed by a heat exchange component  12  provided on the back side in the flowing direction of the heat transport medium  20 . 
     In this description, being parallel includes not only being completely parallel, but also an error range in which the function and effect described later can be substantially achieved. Furthermore, being perpendicular includes not only being completely perpendicular, but also an error range in which the function and effect described later can be substantially achieved. 
     The arrangement configuration of the heat exchange components  12  as described above can form many turbulent portions when the heat transport medium  20  flows inside the container  11 . This can increase the heat transport medium  20  contributing to heat exchange near the heat exchange components  12 . As a result, the heat exchange efficiency between the heat exchange component  12  and the heat transport medium  20  can be improved. The details on the turbulent state occurring in the flow of the heat transport medium  20  will be described later. 
     The heat exchange components  12  are arranged parallel to the y direction. This can suppress the pressure loss of the heat transport medium  20  during the operation of the magnetic refrigeration system. 
     The longest side  12   a  of the heat exchange component  12  is directed parallel to the direction of the magnetic field (z direction). This can suppress the influence of the demagnetizing field when a magnetic field is applied to the heat exchange component  12 . Thus, the effective magnetic field can be enhanced. Accordingly, a magnetic refrigeration system with high refrigeration performance can be provided. 
     In this case, in order to enhance the effective magnetic field, a higher aspect ratio of the heat exchange component  12  is more favorable. For instance, in the case where the heat exchange component  12  is shaped like a strip, the ratio of the shortest side to the longest side (the side in the z direction) can be set to 1:4 or more, and more preferably 1:7 or more. 
     Next, the cross-sectional shape in the plane parallel to the xy plane of the heat exchange component is illustrated.  FIGS. 4A to 4E  are schematic sectional views for illustrating the cross-sectional shape in the plane parallel to the xy plane of the heat exchange component. 
     The cross-sectional shape in the plane parallel to the xy plane of the heat exchange component  12  illustrated in  FIG. 1A  and  FIGS. 3A to 3C  is a rectangle, but is not limited thereto. 
     For instance, as illustrated in  FIG. 4A , the cross-sectional shape in the plane parallel to the xy plane of a heat exchange component  22  can be a square. 
     Furthermore, as illustrated in  FIG. 4B , the cross-sectional shape in the plane parallel to the xy plane of a heat exchange component  23  can be a triangle. In this case, in view of possible change in the flowing direction of the heat transport medium  20  during the operation of the magnetic refrigeration system, the orientations of the heat exchange component  23   a  and the heat exchange component  23   b  can be made different. For instance, as illustrated in  FIG. 4B , the heat exchange component  23   a  can be arranged so that its vertex is directed to the direction opposite to the y direction, and the heat exchange component  23   b  can be arranged so that its vertex is directed to the y direction. 
     Furthermore, as illustrated in  FIG. 4C , the cross-sectional shape in the plane parallel to the xy plane of a heat exchange component  24  can be a hexagon. 
     Furthermore, as illustrated in  FIG. 4D , the cross-sectional shape in the plane parallel to the xy plane of a heat exchange component  25  can be a circle. 
     The cross-sectional shape in the plane parallel to the xy plane of the heat exchange component is not limited to those illustrated, but can be appropriately modified. For instance, other polygons such as pentagon can also be used, and an ellipse and the like can also be used. Furthermore, for instance, a shape formed from an arbitrary curve, or a shape formed from an arbitrary curve and an arbitrary straight line can also be used. 
     In this case, in the case of having a quadrangular cross-sectional shape like the heat exchange components  12 ,  22 , the pressure loss of the heat transport medium  20  can be suppressed at a low level. Furthermore, many turbulent portions can be formed when the heat transport medium  20  flows inside the container  11 . This can increase the heat transport medium  20  contributing to heat exchange near the heat exchange components  12 ,  22 . As a result, the heat exchange efficiency between the heat exchange component  12 ,  22  and the heat transport medium  20  can be improved. 
     Furthermore, the shape processing of the heat exchange component  12 ,  22  is simplified. This enables manufacturing of the heat exchange component  12 ,  22  with high accuracy. Furthermore, the workability of arranging the heat exchange components  12 ,  22  inside the container  11  can be improved. 
     Furthermore, a cross-sectional shape having a smoother outline, such as a hexagonal cross-sectional shape like the heat exchange component  24  and a circular cross-sectional shape like the heat exchange component  25 , can suppress the pressure loss of the heat transport medium  20  at a lower level. For instance, a cross-sectional shape having a smoother outline can be selected for a heat transport medium  20  having a higher viscosity. 
     Furthermore, as described later, a stable turbulent state can be formed between the heat exchange components. This can increase the heat transport medium  20  contributing to heat exchange near the heat exchange components. Furthermore, heat exchange components having a smooth cross-sectional shape with an angle of 90 degrees or more or a rounded outline can smooth the flow line of the heat transport medium  20 . This can suppress the dead volume (the volume of the heat transport medium  20  contributing less to heat exchange) at a lower level. As a result, the heat exchange efficiency between the heat exchange component and the heat transport medium  20  can be improved. 
     Furthermore, it is also possible to arrange heat exchange components different in cross-sectional shape, cross-sectional area, and arrangement pitch. 
     For instance, as illustrated in  FIG. 4E , heat exchange components  12  and heat exchange components  22  different in cross-sectional shape, cross-sectional area, and arrangement pitch can be arranged. 
     In this case, the arrangement pitch of the heat exchange components  22  provided on the inflow side of the heat transport medium  20  in the container  11  can be made smaller than the arrangement pitch of the heat exchange components  12 . Then, the pressure loss in the region provided with the heat exchange components  22  can be made higher than the pressure loss in the region provided with the heat exchange components  12 . This can rectify the flow of the heat transport medium  20 , which is made uneven upon flowing from the piping into the container  11 . After the inflow, the pressure loss can be reduced by the heat exchange components  12  having a larger arrangement pitch. In this case, in view of possible change in the flowing direction of the heat transport medium  20  during the operation of the magnetic refrigeration system, the heat exchange components  22  having a small arrangement pitch can be provided on both end sides of the container  11 . 
     The shape, dimension, arrangement configuration (such as arrangement pitch and position), number and the like of the heat exchange components can be appropriately modified depending on e.g. the viscosity of the heat transport medium  20  and the operating temperature of the magnetic refrigeration system. 
     Next, the turbulent state occurring in the flow of the heat transport medium  20  is further illustrated. 
       FIGS. 5A and 5B  are schematic views for illustrating the turbulent state occurring in the flow of the heat transport medium  20 . 
       FIG. 5A  shows the case where the heat exchange components  25  having a circular cross-sectional shape are arranged in a regular lattice.  FIG. 5B  shows the case where the heat exchange components  25  having a circular cross-sectional shape are arranged in a staggered lattice. 
     It is assumed that the heat transport medium  20  flows at the same flow rate in a space of the same volume. The flow velocity distribution is shown with monotone shading. In the gap  201 , the flow velocity v is faster than a threshold vc. The gap  201  is represented by a dark shade. In the gap  202 , the flow velocity v is slower than the threshold vc. The gap  202  is represented by a light shade. In  FIG. 5A , the heat exchange components  25  are arranged in a regular lattice. In this case, the gaps  201  having a fast flow velocity are aligned in the direction parallel to the y direction to form a region having a fast flow velocity continuing from the feed to the ejection of the heat transport medium  20 . That is, it is found that the heat transport medium  20  flows selectively and rapidly in the portion having a low channel resistance. 
     On the other hand, in  FIG. 5B , the heat exchange components  25  are arranged in a staggered lattice. In this case, the region having a fast flow velocity continuing from the feed to the ejection of the heat transport medium  20  is not formed. The gaps  202  having a relatively slow flow velocity predominate. 
     Furthermore, as shown in  FIG. 5B , turbulence is observed at many sites  203 . 
     More specifically, in the case where the heat exchange components  25  are arranged in a regular lattice, the heat transport medium  20  flows selectively and rapidly in the portion having a low channel resistance. Furthermore, many portions  27  constitute a dead volume (the volume of the heat transport medium  20  contributing less to heat exchange). This decreases the heat exchange efficiency between the heat exchange component  25  and the heat transport medium  20 . 
     In contrast, in the case where the heat exchange components  25  are arranged in a staggered lattice, the flow velocity can be made generally slower than in the case where the heat exchange components  25  are arranged in a regular lattice. Furthermore, turbulence can be caused at many sites  203  between the heat exchange components  25 . This turbulence occurs in a large gap between the adjacent heat exchange components  25 . Thus, the portions  27  constituting a dead volume can be reduced. This also facilitates heat exchange between the heat exchange components  25 . As a result, the effective heat exchange efficiency can be increased. 
     As shown in  FIG. 5A , in the case where the heat exchange components  25  are arranged in a regular lattice, the turbulence only forms a small vortex slightly at the end portion of the heat exchange components  25 . It is found that this does not contribute to heat exchange between the adjacent heat exchange components  25 . 
     Next, the relationship between the arrangement configuration of the heat exchange components and the amount of heat exchange is illustrated. 
       FIGS. 6A and 6B  are schematic views for illustrating the arrangement configuration of the heat exchange components. Here,  FIG. 6A  is a schematic view for illustrating an example (Practical example 1) of the arrangement configuration of the heat exchange components according to this embodiment.  FIG. 6B  is a schematic view for illustrating an arrangement configuration of the heat exchange components according to Comparative example 1. 
     As shown in  FIG. 6A , in the arrangement configuration of the heat exchange components according to Practical example 1, the heat exchange components  22  were periodically arrayed in a staggered lattice. The heat exchange components  22  were arranged parallel to the y direction and parallel to each other. The dimension d 1  between the heat exchange components  22  in the x direction, the dimension d 2  between the heat exchange components  22  in the y direction, and the dimension a 1  of the heat exchange component  22  were set so that d 1 =0.7×a 1  and d 2 =0.5×a 1 . Then, the adjacent columns were displaced by half phase in the x direction so that the heat exchange components  22  were periodically arrayed in a staggered lattice. 
     As shown in  FIG. 6B , in the arrangement configuration of the heat exchange components according to Comparative example 1, the heat exchange components  22  were periodically arrayed in a regular lattice. The heat exchange components  22  were arranged parallel to the y direction and parallel to each other. The dimension d 1  between the heat exchange components  22  in the x direction, the dimension d 2  between the heat exchange components  22  in the y direction, and the dimension a 1  of the heat exchange component  22  were set so that d 1 =0.7×a 1  and d 2 =0.5×a 1 . 
     Then, it was assumed that the heat transport medium  20  was fed to fill the space other than the heat exchange components  22  and caused to flow therein. In this assumption, the amount of heat exchange between the heat exchange component  22  and the heat transport medium  20  was determined by simulation. 
     In this case, it was assumed that the heat transport medium  20  was water, the ambient temperature was 25° C., the frequency of the magnetic refrigeration cycle was 1 Hz, and the flow distance of the heat transport medium  20  was 10×a 1 . Then, the amount of heat exchange between the heat exchange component  22  and the heat transport medium  20  per unit time was calculated. 
     The amount of heat exchange was calculated under the assumption that the periodic structure illustrated in  FIGS. 6A and 6B  were infinitely repeated. In this case, in those illustrated in  FIGS. 6A and 6B , the volume of the heat exchange components  22  in the same capacity is equal. 
     Furthermore, as Practical example 2, the dimensional relation in Practical example 1 was changed to d 1 =0.8×a 1  and d 2 =0.2×a 1 . 
     As Comparative example 2, the dimensional relation in Comparative example 1 was changed to d 1 =0.8×a 1  and d 2 =0.2×a 1 . 
     The other conditions in Practical example 2 and Comparative example 2 were made the same as those in Practical example 1 and Comparative example 1. 
       FIGS. 7A and 7B  are graphs for illustrating the comparison between the amount of heat exchange of the practical example and the amount of heat exchange of the comparative example. Here,  FIG. 7A  is a graph for illustrating the comparison between the amount of heat exchange of Practical example 1 and the amount of heat exchange of Comparative example 1.  FIG. 7B  is a graph for illustrating the comparison between the amount of heat exchange of Practical example 2 and the amount of heat exchange of Comparative example 2. 
     As seen from  FIG. 7A , in Practical example 1, the amount of heat exchange can be made larger than in Comparative example 1. 
     As seen from  FIG. 7B , in Practical example 2, the amount of heat exchange can be made larger by 20% or more than in Comparative example 2. 
     Thus, even in the case of heat exchange components having an equal volume in the same capacity and also placed with an equal spacing between the heat exchange components, it was confirmed that the amount of heat exchange between the heat exchange component and water can be made larger for a periodic array in a staggered lattice than for a periodic array in a regular lattice. 
     That is, a plurality of heat exchange components are regularly arrayed in the container. Furthermore, the heat transport medium  20  such as water is fed to fill the container. While causing the heat transport medium  20  to flow therein, heat exchange is performed between the heat exchange component and the heat transport medium  20 . In this case, the arrangement configuration of the heat exchange components according to this embodiment can increase the amount of heat exchange. 
     Next, methods for arranging the heat exchange components are illustrated. 
     As illustrated in  FIG. 1B , the heat exchange components can be fixed at the end portion in the z direction. 
     In this case, a group of heat exchange components can be formed outside the container  11  and placed inside the container  11 . This can improve the productivity. 
       FIGS. 8A to 8D  are schematic views for illustrating a method for arranging the heat exchange components. 
     As shown in  FIG. 8A , a group of heat exchange components  22   a  with one end portion in the z direction fixed, and a group of heat exchange components  22   b  with the other end portion in the z direction fixed, can be formed and alternately placed inside the container  11 . Here,  FIGS. 8A to 8D  show the case of forming the groups of heat exchange components along the y direction. 
     For instance, groups of heat exchange components  22   a ,  22   b  as illustrated in  FIGS. 8B ,  8 C, and  8 D can be formed and alternately placed inside the container  11 . 
     In this case, one end portions of the plurality of heat exchange components  22   a  are connected to each other via a plate-like member. One end portions of the plurality of heat exchange components  22   b  are connected to each other via a plate-like member. 
       FIGS. 9A to 9D  are also schematic views for illustrating a method for arranging the heat exchange components. 
     As shown in  FIG. 9A , a group of heat exchange components  22   a  with one end portion in the z direction fixed, and a group of heat exchange components  22   b  with the other end portion in the z direction fixed, can be formed and alternately placed inside the container  11 . Here,  FIGS. 9A to 9D  show the case of forming the groups of heat exchange components along the x direction. 
     For instance, groups of heat exchange components  22   a ,  22   b  as illustrated in  FIGS. 9B ,  9 C, and  9 D can be formed and alternately placed inside the container  11 . 
       FIGS. 10A and 10B  are also schematic views for illustrating a method for arranging the heat exchange components. 
     As shown in  FIG. 10A , a group of heat exchange components  22   a ,  22   b  with one end portion in the z direction fixed can be formed and placed inside the container  11 . 
     For instance, a group of heat exchange components  22   a ,  22   b  as illustrated in  FIG. 10B  can be formed and placed inside the container  11 . 
     The heat exchange components according to the above embodiment are integrated in the z direction. However, the heat exchange components can also be divided in the z direction. 
     The foregoing relates to the case of arranging heat exchange components formed from the same magnetocaloric effect material. However, the embodiment is not limited thereto. 
     The characteristics of the magnetocaloric effect material are maximized near the Curie temperature Tc. In the temperature region too distant from the Curie temperature Tc, the characteristics may be significantly degraded, or the magnetocaloric effect may fail to be developed. 
     As described above, the magnetic refrigeration system based on the AMR technique is operated with a temperature gradient formed between both ends (high temperature end and low temperature end) of the heat exchanger. Thus, arranging heat exchange components formed from the same magnetocaloric effect material may partly produce a portion with degraded characteristics. 
       FIGS. 11A and 11B  are schematic sectional views for illustrating cases of arranging heat exchange components formed from different magnetocaloric effect materials. 
       FIG. 11A  shows the case of arranging groups of heat exchange components formed from different magnetocaloric effect materials along the y direction. More specifically, the heat exchange components are formed from a different magnetocaloric effect material for each region provided along the flowing direction of the heat transport medium  20 . 
     For instance,  FIG. 11A  shows the case of selecting magnetocaloric effect materials having Curie temperatures Tc suited to the temperature gradient, and providing groups of heat exchange components formed from the selected magnetocaloric effect materials. 
     For instance, in  FIG. 11A , the inflow side of the heat transport medium  20  is the low temperature end, and the outflow side is the high temperature end. Then, a magnetocaloric effect material having the Curie temperature Tca suited to the temperature of the low temperature end is selected, and heat exchange components  32   a  are formed from the selected magnetocaloric effect material. A magnetocaloric effect material having the Curie temperature Tcc suited to the temperature of the high temperature end is selected, and heat exchange components  32   c  are formed from the selected magnetocaloric effect material. For the region between the low temperature end and the high temperature end, a magnetocaloric effect material having the Curie temperature Tcb suited to the temperature of that region is selected, and heat exchange components  32   b  are formed from the selected magnetocaloric effect material. 
     This can suppress partial characteristics degradation, and thus can improve the heat exchange efficiency. 
     The number of regions provided with the groups of heat exchange components is not limited to those illustrated, but can be appropriately modified. 
       FIG. 11B  shows the case of arranging heat exchange components formed from magnetocaloric effect materials having different Curie temperatures Tc in a mixed manner. 
     This can expand the operating temperature region of the magnetic refrigeration system. 
     Here, for instance, also in the case of forming groups of heat exchange components as illustrated in  FIGS. 10A to 11B , it is preferable to provide a magnetic field generating section so that the application direction of the magnetic field is directed in the z direction (parallel to the longest side of each heat exchange component). 
     Second Embodiment  
       FIG. 12  is a schematic configuration view for illustrating a magnetic refrigeration system according to a second embodiment. 
       FIG. 13  is a schematic line diagram of the magnetic refrigeration system according to the second embodiment. 
     Here,  FIGS. 12 and 13  illustrate, as an example, the case where a heat transport medium  20  subjected to heat absorption in a heat exchange section  1  is sent to a low temperature side heat exchange section  125  and caused to perform heat exchange with a heat exchange target, not shown, in the low temperature side heat exchange section  125 . 
     As shown in  FIGS. 12 and 13 , the magnetic refrigeration system  100  includes heat exchangers  1 , a feed piping  103 , an ejection piping  104 , a magnetic field generating section  105   a , a magnetic field generating section  105   b , a rotary board  106   a , a rotary board  106   b , a low temperature side heat exchange section  125 , and a heat dissipating section  126 . 
     As shown in  FIG. 12 , a pair of rotary boards  106   a ,  106   b  are provided so as to sandwich two heat exchange sections  1  therebetween. The rotary boards  106   a ,  106   b  are supported by a common shaft  107 . This shaft  107  is located at the center of the two heat exchange sections  1 . The magnetic field generating sections  105   a ,  105   b  are held inside the neighborhood of the periphery of the rotary boards  106   a ,  106   b , respectively. The magnetic field generating sections  105   a ,  105   b  are opposed to each other, and coupled via a yoke (not shown) to each other. Thus, a magnetic field space is formed in the gap between the magnetic field generating sections  105   a ,  105   b  paired with each other. 
     The magnetic field generating section  105   a ,  105   b  can be e.g. a permanent magnet. The permanent magnet can be e.g. a NdFeB (neodymium-iron-boron) magnet, SmCo (samarium-cobalt) magnet, or ferrite magnet. Each time the rotary boards  106   a ,  106   b  are rotated 90 degrees, the magnetic field generating section  105   a ,  105   b  repeat approach and separation with respect to the heat exchange sections  1 . In the state in which a pair of magnetic field generating sections  105   a ,  105   b  come closest to the respective heat exchange sections  1 , the heat exchange section  1  is located in the magnetic field space formed between the magnetic field generating sections  105   a ,  105   b . Thus, a magnetic field is applied to the heat exchange component provided inside the container  11 . When the state of the magnetic field being applied to the heat exchange component is switched to the state of the magnetic field being removed, the entropy of the electron magnetic spin system increases. This causes migration of entropy between the lattice system and the electron magnetic spin system. Accordingly, the temperature of the heat exchange component decreases. This is transferred to the heat transport medium  20  and decreases the temperature of the heat transport medium  20 . The heat transport medium  20  with the temperature thus decreased is ejected from the heat exchange section  1  through the ejection piping  104  and supplied as a coolant to the low temperature side heat exchange section  125 . 
     The heat transport medium  20  can be e.g. a gas such as air and nitrogen gas, water, an oil-based medium such as mineral oil and silicone, or a solvent-based medium such as alcohols (e.g., ethylene glycol). 
     In this case, water has the highest specific heat and is inexpensive. However, water may freeze in the temperature region of 0° C. or less. Thus, it is possible to use e.g. an oil-based medium, a solvent-based medium, a mixed liquid of water and an oil-based medium, or a mixed liquid of water and a solvent-based medium. Depending on the operating temperature region of the magnetic refrigeration system  100 , the liquid can be appropriately modified in kind and mixing ratio. 
     In the case illustrated in  FIG. 12 , the magnetic field generating sections  105   a ,  105   b , the rotary boards  106   a ,  106   b , the shaft  107  and the like constitute a magnetic field changing section for changing the magnetic field to the heat exchanger  1 . 
     In the case illustrated in  FIG. 12 , mechanical variation is applied to the magnetic field generating section  105   a ,  105   b  side. However, mechanical variation may be applied to the heat exchanger  1  side. 
     In the foregoing, as the magnetic field generating section  105   a ,  105   b , a permanent magnet is illustrated. However, for instance, an electromagnet can also be used as the magnetic field generating section  105   a ,  105   b . In the case of using an electromagnet as the magnetic field generating section  105   a ,  105   b , means for applying mechanical variation can be connected to the magnetic field generating section  105   a ,  105   b . However, alternatively, it is also possible to provide e.g. a switch for switching between energization and deenergization of the electromagnet. 
     On the upstream side of the feed piping  103 , a tank  121  storing the heat transport medium  20  is provided. In the midstream of the feed piping  103 , a transport section  122  is provided. The transport section  122  feeds the heat exchange section  1  with the heat transport medium  20 . The ejection piping  104  is divided into two lines after exiting the heat exchange section  1  to constitute two circulation lines. In the midstream of one circulation line (cooling line  123 ), a valve  131 , the low temperature side heat exchange section  125 , and a valve  133  are provided. The tail end of the cooling line  123  is connected to the tank  121 . In the midstream of the other circulation line (precooling line  124 ), a valve  132 , the heat dissipating section  126 , and a valve  134  are provided. The tail end of the precooling line  124  is connected to the tank  121 . 
     Furthermore, a control section, not shown, for controlling e.g. the operation of the rotary boards  106   a ,  106   b  and the opening/closing operation of the valves  131 - 134  is provided. 
     Next, the operation of the magnetic refrigeration system  100  is illustrated. 
     The magnetic refrigeration system  100  is operated by alternately repeating a precooling step and a cooling step. 
     First, in the precooling step, with the valve  131  and the valve  133  closed, the valves  132  and  134  are opened to circulate the heat transport medium  20  in the precooling line  124 . In this state, the magnetic field generating sections  105   a ,  105   b  are made close to the heat exchange sections  1 . When a magnetic field is applied to the heat exchange components provided inside the container  11 , the temperature of the heat exchange components increases. This is transferred to the heat transport medium  20  and increases the temperature of the heat transport medium  20 . The heat transport medium  20  thus warmed is ejected from the heat exchange section  1  through the ejection piping  104  and fed through the valve  132  into the heat dissipating section  126 , where it is cooled. The cooled heat transport medium  20  returns into the tank  121  through the valve  134 . 
     When the temperature of the heat exchange components provided inside the container  11  has decreased close to the temperature of the heat transport medium  20  supplied through the feed piping  103  to the heat exchange sections  1 , the valves  132 ,  134  are closed. Thus, the precooling step is terminated and passed to the cooling step. 
     In the cooling step, first, the magnetic field generating sections  105   a ,  105   b  are distanced from the heat exchange sections  1 . Next, the valve  131  and the valve  133  are opened to circulate the heat transport medium  20  in the cooling line  123 . When the magnetic field is removed from the heat exchange components, the temperature of the heat exchange components decreases. This is transferred to the heat transport medium  20  and decreases the temperature of the heat transport medium  20 . The heat transport medium  20  thus cooled is ejected from the heat exchange section  1  through the ejection piping  104  and fed through the valve  131  into the low temperature side heat exchange section  125 . In the low temperature side heat exchange section  125 , heat exchange is performed between the heat transport medium  20  subjected to heat absorption in the heat exchanger  1  and a heat exchange target, not shown. The low temperature side heat exchange section  125  can be e.g. a section for cooling air by performing heat exchange between the heat transport medium  20  at low temperature and air. 
     The heat transport medium  20  is subjected to heat exchange in the low temperature side heat exchange section  125 , and its temperature is increased. Then, the heat transport medium  20  returns into the tank  121  through the valve  133 . 
     When the temperature of the heat exchange components provided inside the container  11  has increased close to the temperature of the heat transport medium  20  supplied through the feed piping  103  to the heat exchange sections  1 , the valves  131 ,  133  are closed. Thus, the cooling step is terminated and passed again to the precooling step. 
     In this case, the control section, not shown, controls e.g. the operation of the rotary boards  106   a ,  106   b  and the opening/closing operation of the valves  131 - 134 , and alternately repeats the precooling step and the cooling step described above. 
     In the foregoing, as an example, the magnetic refrigeration system using the heat absorption effect in the heat exchange sections  1  is illustrated. However, the embodiment is not limited thereto. For instance, the magnetic refrigeration system can also be configured to use the heat generation effect in the heat exchange sections  1 . Alternatively, the magnetic refrigeration system can also be configured to use the heat absorption effect and the heat generation effect in the heat exchange sections  1 . For instance, the heat dissipating section  126  provided in the magnetic refrigeration system  100  can be used as a high temperature side heat exchange section to perform heat exchange between the heat transport medium  20  at high temperature and air. Thus, in this example, air can be heated. 
     The heat transport medium  20  transports cool heat or warm heat to the low temperature side heat exchange section or the high temperature side heat exchange section. The heat transport from the low temperature side heat exchange section or the high temperature side heat exchange section to the cooled section or the heat dissipating section is preferably performed by a gas such as air, helium, and carbon dioxide. 
     The embodiments described above can realize a heat exchanger and a magnetic refrigeration system capable of improving the heat transport efficiency. 
     While certain embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the inventions. Indeed, the novel embodiments described herein may be embodied in a variety of other forms; furthermore, various omissions, substitutions and changes in the form of the embodiments described herein may be made without departing from the spirit of the inventions. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the inventions. Moreover, above-mentioned embodiments can be combined mutually and can be carried out. 
     For instance, the shape, dimension, material, layout, number and the like of various components in the heat exchanger  1 , the magnetic refrigeration system  100  and the like are not limited to those illustrated above, but can be appropriately modified.