US20130017386A1

US20130017386A1 - Magnetocaloric material structure

Info

Publication number: US20130017386A1
Application number: US13/546,457
Authority: US
Inventors: Tiao-Yuan WU; Sheng-Fan HSIEH; Chieh-Shih CHANG; Ming-Han Lin; Chung-Jung Kuo
Original assignee: Delta Electronics Inc
Current assignee: Delta Electronics Inc
Priority date: 2011-07-12
Filing date: 2012-07-11
Publication date: 2013-01-17
Also published as: CN102878720A; DE102012106252A1

Abstract

A magnetocaloric material structure is disclosed. The magnetocaloric material structure includes a magnetocaloric material body and a plurality of channels. The channels are located in the magnetocaloric material body. The cross-section of the channels has a center disposed according to the following formula: L₃ ²≠L₁ ²+L₂ ². Wherein, L₁is the minimum value of the length of the lines between the adjacent centers parallel or perpendicular to a direction; L₂is the maximum value of the length of the lines between the adjacent centers parallel or perpendicular to the direction; L₃is the minimum value of the length of the lines between the adjacent centers not parallel or perpendicular to the direction. Another magnetocaloric material structure, which includes a magnetocaloric material body and a plurality of channels, is disclosed. The cross-section of each channel is in a non-circular and non-rectangular shape, which is a symmetric or asymmetric shape.

Description

CROSS REFERENCE TO RELATED APPLICATIONS

The non-provisional patent application claims priority to U.S. provisional patent application with Ser. No. 61/506,943 filed on Jul. 12, 2011. This and all other extrinsic materials discussed herein are incorporated by reference in their entirety.

BACKGROUND OF THE INVENTION

1. Field of Invention
The invention relates to a magnetocaloric material structure.
2. Related Art
The materials with the magnetocaloric property are called the magnetocaloric materials (MCM). Under the affect of an external magnetic field, the temperature of the magnetocaloric material can be increased or decreased due to the intensity of the magnetic field. Thus, the magnetocaloric material can be used to manufacture the magnetocaloric heater or cooler.
FIG. 1A shows a conventional magnetocaloric material structure 1. As shown in FIG. 1A, a magnetocaloric material body 10 is accommodated in a magnetocaloric material container 11. A plurality of channels 12 are configured in the magnetocaloric material body 10 and make it through the body. The configuration of the channels 12 is used for flowing the working fluid, so that the heat exchange between the magnetocaloric material body 10 and the working fluid can be performed. The cross-section and arrangement of the conventional channels 12 are shown in FIG. 1A. In more details, the cross-section of the channels 12 is in a circular shape, and they are arranged in an array. An external magnetic field, which passes the magnetocaloric material structure 1 along the direction B, is applied.
To be noted, the definition of the term “array” will be described hereinafter with reference to FIG. 1B. The cross-section of each channel 12 has a center, and the centers of the channels are arranged based on the following formula of: L₃ ²=L₁ ²+L₂ ². Wherein, L₁is the minimum value of the length of the lines between the adjacent centers parallel or perpendicular to a direction B; L₂is the maximum value of the length of the lines between the adjacent centers parallel or perpendicular to the direction B; L₃is the minimum value of the length of the lines between the adjacent centers not parallel or perpendicular to the direction B.
The conventional magnetocaloric material structure and its size are designed based on the properties of the heat transfer ability, power loss, mechanical strength, and processing ability. However, the other factors such as the magnetic resistance of the magnetic field, the part of the volume that is not affected by the magnetic field, and the structural strength are not considered. For example, in the conventional magnetocaloric material structure 1, the magnetic flux lines Lm₁(see FIG. 1A) of the magnetic field do not pass through the areas A₁of the magnetocaloric material body 10, each of which is located between adjacent channels 12 along the direction B. In other words, the magnetocaloric material body 10 within the areas A₁is not affected by the magnetic field, so that the magnetocaloric effect does not occur in these areas A₁. Besides, the magnetic resistance of the magnetic field passing through the circular channels 12 is larger, so that the magnetocaloric material structure 1 can not reach the maximum performance.
Therefore, it is an important subject of the invention to provide a magnetocaloric material structure that can enhance the magnetocaloric transform capability and increase the structural strength.

SUMMARY OF THE INVENTION

In view of the foregoing, an objective of the present invention is to provide a magnetocaloric material structure that can enhance the magnetocaloric transform efficiency and increase the structural strength.
To achieve the above objective, the present invention discloses a magnetocaloric material structure, which includes a magnetocaloric material body and a plurality of channels. The channels are configured inside the magnetocaloric material body. The cross-section of each channel has a center, and the centers of the channels are arranged based on the following formula of: L₃ ²≠L₁ ²+L₂ ². Wherein, L₁is a minimum distance between adjacent two of the centers while a line passes through the two adjacent centers is parallel to or perpendicular to a direction, L₂is a maximum distance between adjacent two of the centers while a line passes through the two adjacent centers is parallel to or perpendicular to the direction, and L₃is a minimum distance between adjacent two of the centers while a line passes through the two adjacent centers is not parallel to or perpendicular to the direction.
In one embodiment, the direction is a magnetic direction passing through the magnetocaloric material body.
In one embodiment, the center is a geometrical center or a gravity center.
In one embodiment, the channels are arranged in misalignment.
In one embodiment, a working fluid flows through the channels. The working fluid includes an anti-corrosion additive, an anti-freeze additive, an additive for reducing a resistance between the working fluid and walls of the channels, or their combination.
In one embodiment, L₁is equal to 0.
To achieve the above objective, the present invention also discloses a magnetocaloric material structure, which includes a magnetocaloric material body and a plurality of channels. The channels are configured inside the magnetocaloric material body. A cross-section of each channel is in a non-circular and non-rectangular shape, which is a symmetric shape or an asymmetric shape.
In one embodiment, the symmetric shape is a triangle, a rhombus, a kite, a trapezoid, a polygon (pentagon, hexagon or more), an ellipse, a drop shape, a shuttle shape, a sector, or their combinations.
In one embodiment, the asymmetric shape is any shape except the symmetric shapes mentioned in the previous embodiments.
In one embodiment, a corner of the cross-section of the non-circular and non-rectangular shape is a round corner, a non-sharp corner, or their combination.
In one embodiment, the channels are arranged in misalignment.
In one embodiment, the non-circular and non-rectangular shape has a corner with an acute angle.
In one embodiment, a working fluid flows through the channels. The working fluid includes an anti-corrosion additive, an anti-freeze additive, an additive for reducing a resistance between the working fluid and walls of the channels, or their combination.
As mentioned above, the magnetocaloric material structure of the invention has a specific arrangement or cross-section of the channels, so that the magnetic resistance of the magnetocaloric material structure can be decreased, and/or the part of the volume of the magnetocaloric material body that is affected by the magnetic field can be enlarged. Besides, the tight arrangement of the magnetocaloric material structure can enhance the heat transfer efficiency and ability. This can also sufficiently increase the performance of the magnetocaloric material structure. The specific shape of the cross-section of the channels can further increase the structural strength. Moreover, when the magnetocaloric material structure is applied with the proper working fluid, which may include the anti-corrosion additive, anti-freeze additive, and an additive for reducing resistance, the magnetocaloric material structure can be applied to the severe working environments or situations. Besides, this can also decrease the power lose while the working fluid is flowing in the channels.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become more fully understood from the subsequent detailed description and accompanying drawings, which are given by way of illustration only, and thus are not limitative of the present invention, and wherein:

FIG. 1A and FIG. 1B are schematic diagrams showing the conventional magnetocaloric material structure;

FIG. 2A is a cross-sectional view of a magnetocaloric material structure according to a first embodiment of the invention;

FIG. 2B is a schematic diagram showing a portion of the magnetocaloric material structure of FIG. 2A;

FIG. 3A is a cross-sectional view of a magnetocaloric material structure according to a second embodiment of the invention;

FIG. 3B is a schematic diagram showing a portion of the magnetocaloric material structure of FIG. 3A;

FIGS. 4A to 4F are schematic diagrams showing different aspects of the cross-section of the channels; and

FIGS. 5A to 5C are schematic diagrams showing different aspects of the cross-section of the channels.

DETAILED DESCRIPTION OF THE INVENTION

The present invention will be apparent from the following detailed description, which proceeds with reference to the accompanying drawings, wherein the same references relate to the same elements.
FIG. 2A is a cross-sectional view of a magnetocaloric material structure 2 according to a first embodiment of the invention, and FIG. 2B is a schematic diagram showing a portion of the magnetocaloric material structure 2 of FIG. 2A. Referring to FIG. 2A and FIG. 2B, the magnetocaloric material structure 2 includes a magnetocaloric material body 20 and a plurality of channels 22. In more details, the magnetocaloric material body 20 is accommodated in a magnetocaloric material container 21, and the channels 22 are configured in the magnetocaloric material body 20 and pass through it. The configuration of the channels 22 is used for performing heat exchange so as to achieve fast cooling and heating. If the magnetocaloric material structure 2 is applied to a heater or a cooler, a magnetic field with magnetic flux lines passing through the magnetocaloric material structure 2 is needed. Under the effect of the magnetic field, the temperature of the magnetocaloric material body 20 can be increased or decreased based on the intensity of the magnetic field.
The channels 22 are configured in a specific arrangement as illustrated hereinafter. The cross-section of each channel 22 has a center, and adjacent two centers, while a line passes through the two adjacent centers is parallel to or perpendicular to a direction, are connected. The centers of the channels 22 are arranged based on the following formula of: L₃ ²≠L₁ ²+L₂ ². Wherein, L₁is a minimum distance between adjacent two of the centers while a line passes through the two adjacent centers is parallel to or perpendicular to a direction, L₂is a maximum distance between adjacent two of the centers while a line passes through the two adjacent centers is parallel to or perpendicular to the direction, and L₃is a minimum distance between adjacent two of the centers while a line passes through the two adjacent centers is not parallel to or perpendicular to the direction. In this case, the center of the channel 22 is a geometrical center or a gravity center, and the direction is a magnetic direction B passing through the magnetocaloric material body 20. In practice, the channels 22 are arranged in misalignment, which is different from the conventional arrangement (as shown in FIG. 1B, wherein L₃ ²=L₁ ²+L₂ ²).
FIG. 2A shows the magnetic flux lines Lm₂of the magnetic field applied to the magnetocaloric material body 20. Although there still have some areas A₂, through which the magnetic flux lines Lm₂do not pass, the dimension of the areas A₂is obviously smaller than that of the areas A₁of the magnetocaloric material structure 1 shown in FIG. 1A. This means that the magnetocaloric material body 20 that is affected by the magnetic field is enlarged. Thus, more percentage of the magnetocaloric material body 20 is used for enhancing the magnetocaloric effect of the magnetocaloric material structure 2. This is the purpose for arranging the channels 22 in misalignment.
In addition, the channels 22 may be arranged in other aspects different from that shown in FIGS. 2A and 2B. To be noted, any aspect of the arrangement of the channels 22 must follow the equation of L₃ ²≠L₁ ²+L₂ ², wherein L₁is equal to 0. In more detailed, it is not exist that a line passing through two adjacent centers of the channels 22 in this arrangement is parallel to (or perpendicular to) the direction.
In this embodiment, the working fluid (not shown) can flow through the channels 22, so that the heat exchange between the magnetocaloric material body 20 and the working fluid can be carried out. In order to allow the magnetocaloric material structure 2 to be used in more severe working environments or situations, the working fluid may further include an anti-corrosion additive for protecting the magnetocaloric material body 20 and the magnetocaloric material container 21 from the corrosion of the working fluid, an anti-freeze additive for preventing the frozen of the working fluid and increasing the working temperature range, or an additive for reducing a resistance between the working fluid and walls of the channels so as to decrease the power lose caused by the resistance therebetween. Of course, it is also possible to add any combination of the above additives in the working fluid.
Regardless the arrangement of the channels 22 and regarding only to the cross-section of the channels, it is possible to design various aspects of the shape of the cross-section of channel. The following describes some examples of the aspects of the shape of the cross-section of the channels with reference to FIGS. 4A to 4F and FIGS. 5A to 5C, but these examples are for illustrations only and are not to limit the scope of the invention.
To be noted, the various designs of the cross-section of the channel are for the purpose of decreasing the magnetic resistance of the magnetocaloric material structure or increasing the dimensions of the areas that are affected by the magnetic field. Typically, if the shape of the cross-section of the channel is closer to the streamline shape, the magnetic resistance of the magnetocaloric material structure is smaller. In addition, if one end of the cross-section of the channel passed by the magnetic field has smaller acute angle or larger curvature, the percentage of the magnetocaloric material body affected by the magnetic field is greater. Besides, if the shape of the cross-section of the channels allows the channels to be arranged more tightly, the heat exchange ability, efficiency and structural strength of the magnetocaloric material structure can be further enhanced.
FIGS. 4A to 4F are schematic diagrams showing the shapes of the cross-section of channels 22 a, 22 b, 22 c, 22 d, 22 e, and 22 f. These six aspects are all symmetric and basic geometry structures. The shape of the cross-section of the channel 22 a as shown in FIG. 4A is an ellipse. It has the advantages of smaller magnetic resistance and more percentage of the magnetocaloric material body that is affected by the magnetic field. The shape of the cross-section of the channel 22 b as shown in FIG. 4B is a triangle. It has the advantage of high arrangement density of the channels 22 b. Besides, the triangle has at least one acute angle, and a portion of the magnetocaloric material body in front of the acute angle that is not affected by the magnetic field is smaller. The shape of the cross-section of the channel 22 c as shown in FIG. 4C is a rhombus. It has the advantage of high arrangement density of the channels 22 c. Besides, the rhombus has two acute angles, and the portions of the magnetocaloric material body in front of the acute angles that are not affected by the magnetic field are smaller. The shape of the cross-section of the channel 22 d as shown in FIG. 4D is a trapezoid. It has the advantage of high arrangement density of the channels 22 d. The shape of the cross-section of the channel 22 e as shown in FIG. 4E is a hexagon. It has the advantages of high arrangement density of the channels 22 e and higher structural strength. The shape of the cross-section of the channel 22 f as shown in FIG. 4F is a sector. It has the advantage of high arrangement density of the channels 22 f. Besides, the sector has one acute angle, and the portion of the magnetocaloric material body in front of the acute angle that is not affected by the magnetic field is smaller.
FIGS. 5A to 5C are schematic diagrams showing the shapes of the cross-section of channels 22 g, 22 h, and 22 i. The first two aspects show the symmetric combinations of the previous mentioned basic geometry structures. The shape of the cross-section of the channel 22 g as shown in FIG. 5A is a drop shape. It has the advantage of high arrangement density of the channels 22 g. Besides, the drop shape also has one acute angle, and the portion of the magnetocaloric material body in front of the acute angle that is not affected by the magnetic field is smaller. The shape of the cross-section of the channel 22 h as shown in FIG. 5B is a shuttle shape. It has the advantage of high arrangement density of the channels 22 h. Besides, the shuttle shape has two acute angles, and the portions of the magnetocaloric material body in front of the acute angles that are not affected by the magnetic field are smaller. The third aspect is to modify one of the basic geometry structures, for example, to modify the sharp angle into a round angle or a non-sharp angle. As shown in FIG. 5C, the shape of the cross-section of the channel 22 i is a shape by modifying the corners of a rectangle. It has the advantage that the portions of the magnetocaloric material body around the round corners that are not affected by the magnetic field are smaller.
Besides, the shape of the cross-section of the channel can also be a kite, a polygon (pentagon, hexagon or more), or the combinations of any of the above-mentioned shapes. Of course, the cross-section of the channel may have an asymmetric shape which is not the symmetric shapes mentioned in previous embodiments or aspects, such as a non-isosceles triangle or a non-isosceles trapezoid. The shape of the cross-section of the channel can have various designs based on the magnetocaloric effect, heat transfer efficiency and ability, and the structural strength.
Besides, FIG. 3A is a cross-sectional view of a magnetocaloric material structure 3 according to a second embodiment of the invention, and FIG. 3B is a schematic diagram showing a portion of the magnetocaloric material structure 3 of FIG. 3A. Reference to FIGS. 3A and 3B, this embodiment combines the structures as shown in FIG. 4C and FIG. 2A. Similarly, the magnetocaloric material structure 3 includes a magnetocaloric material body 30 and a plurality of channels 32. The magnetocaloric material body 30 is accommodated in a magnetocaloric material container 31, and the channels 32 are configured in the magnetocaloric material body 30. In the magnetocaloric material structure 3, the arrangement of the channels 32 is the same as that described in the first embodiment, so that the centers of the channels 32 are arranged according to the following formula of: L₃ ²≠L₁ ²+L₂ ². Wherein, L₁is a minimum distance between adjacent two of the centers while a line passes through the two adjacent centers is parallel to or perpendicular to a direction B, L₂is a maximum distance between adjacent two of the centers while a line passes through the two adjacent centers is parallel to or perpendicular to the direction B, and L₃is a minimum distance between adjacent two of the centers while a line passes through the two adjacent centers is not parallel to or perpendicular to the direction B. In other words, the channels 32 can be arranged in misalignment. FIG. 3A shows the magnetic flux lines Lm₃of the magnetic field applied to the magnetocaloric material body 30. The dimension of the areas A₃, through which the magnetic flux lines Lm₃do not pass, is obviously smaller than that of the above-mentioned areas A₁.
The cross-section of each channel 32 is in a non-circular and non-rectangular shape, and this non-circular and non-rectangular shape can be a symmetric shape or an asymmetric shape. The various aspects of the shape of the cross-section of the channel 32 are similar to those disclosed in FIGS. 4A to 4F and 5A to 5C, so the detailed description thereof will be omitted. To be noted, the shape of the cross-section of the channels 32 in this embodiment is a triangle for example. When some of the triangles are rotated in 180 degrees, the original triangles and the reversed triangles can be arranged more tightly. Any other shape that has this feature can also be used. The advantages for this structure feature are to provide better structural strength, higher heat transfer efficiency and ability, and larger percentage of the magnetocaloric material body that can be affected by the magnetic field.
In addition, as described in the first embodiment, the working fluid used in the magnetocaloric material structure 3 of this embodiment may also further include an anti-corrosion additive, an anti-freeze additive, an additive for reducing a resistance between the working fluid and walls of the channels, or their combination.
In summary, the magnetocaloric material structure of the invention has a specific arrangement or cross-section of the channels, so that the magnetic resistance of the magnetocaloric material structure can be decreased, and/or the volume of part of the magnetocaloric material body that is not affected by the magnetic field can be reduced. Besides, the tight arrangement of the magnetocaloric material structure can enhance the heat transfer efficiency and ability. This can also sufficiently increase the performance of the magnetocaloric material structure. The specific shape of the cross-section of the channels can further increase the structural strength. Moreover, when the magnetocaloric material structure is applied with the proper working fluid, which may include the anti-corrosion additive, anti-freeze additive, and an additive for reducing resistance, the magnetocaloric material structure can be applied to the severe working environments or situations. Besides, this can also decrease the power lose while the working fluid is flowing in the channels.
Although the present invention has been described with reference to specific embodiments, this description is not meant to be construed in a limiting sense. Various modifications of the disclosed embodiments, as well as alternative embodiments, will be apparent to persons skilled in the art. It is, therefore, contemplated that the appended claims will cover all modifications that fall within the true scope of the present invention.

Claims

1. A magnetocaloric material structure, comprising:

a magnetocaloric material body; and

a plurality of channels configured inside the magnetocaloric material body, wherein a cross-section of each of the channels has a center, and the centers of the channels are arranged based on the following formula of:

L ₃ ² ≠L ₁ ² +L ² 2

wherein, L₁is a minimum distance between adjacent two of the centers while a line passes through the two adjacent centers is parallel to or perpendicular to a direction, L₂is a maximum distance between adjacent two of the centers while a line passes through the two adjacent centers is parallel to or perpendicular to the direction, and L₃is a minimum distance between adjacent two of the centers while a line passes through the two adjacent centers is not parallel to or perpendicular to the direction.

2. The magnetocaloric material structure of claim 1, wherein the direction is a magnetic direction passing through the magnetocaloric material body.

3. The magnetocaloric material structure of claim 1, wherein the center is a geometrical center or a gravity center.

4. The magnetocaloric material structure of claim 1, wherein the channels are arranged in misalignment.

5. The magnetocaloric material structure of claim 1, wherein a working fluid flows through the channels.

6. The magnetocaloric material structure of claim 5, wherein the working fluid comprises an anti-corrosion additive, an anti-freeze additive, an additive for reducing a resistance between the working fluid and walls of the channels, or their combination.

7. The magnetocaloric material structure of claim 1, wherein L₁is equal to 0.

8. A magnetocaloric material structure, comprising:

a magnetocaloric material body; and

a plurality of channels configured inside the magnetocaloric material body, wherein a cross-section of each of the channels is in a non-circular and non-rectangular shape, and the non-circular and non-rectangular shape is a symmetric shape or an asymmetric shape.

9. The magnetocaloric material structure of claim 8, wherein the symmetric shape is a triangle, a rhombus, a kite, a trapezoid, a polygon (pentagon, hexagon or more), an ellipse, a drop shape, a shuttle shape, a sector, or their combinations.

10. The magnetocaloric material structure of claim 8, wherein a corner of the cross-section in the non-circular and non-rectangular shape is a round corner, a non-sharp corner, or their combination.

11. The magnetocaloric material structure of claim 8, wherein the channels are arranged in misalignment.

12. The magnetocaloric material structure of claim 8, wherein the non-circular and non-rectangular shape has a corner with an acute angle.

13. The magnetocaloric material structure of claim 8, wherein a working fluid flows through the channels.

14. The magnetocaloric material structure of claim 13, wherein the working fluid comprises an anti-corrosion additive, an anti-freeze additive, an additive for reducing a resistance between the working fluid and walls of the channels, or their combination.