MAGNETIC REFRIGERATION DEVICE

• US 20100071383A1
• Filed: 09/24/2008
• Published: 03/25/2010
• Est. Priority Date: 09/24/2008
• Status: Active Grant

• Current Assignee: Hussmann Corporation (Panasonic Holdings Corporation)
• Original Assignee: Hussmann Corporation (Panasonic Holdings Corporation)
• Inventors: Madireddi, Sesha, Zhang, Ming
• Granted Patent: US 8,209,988 B2
• Time in Patent Office: Days
• US Class Current: 62/3.100
• CPC Class Codes: F25B 21/00 Machines, plants or systems, using electric or magnetic effects
• CPC Class Codes: F25B 2321/0021 with a static fixed magnet
• CPC Class Codes: Y02B 30/00 Energy efficient heating, ventilation or air conditioning [HVAC]

Abstract

A magnetic refrigeration device for transferring heat including a shaft rotatable about an axis, an inner magnet disposed at one of the axis and a radial distance from the axis, an outer magnet disposed a radial distance from the axis outside of the inner magnet defining a magnetic gap between the inner and outer magnets, and magnetocaloric material disposed at a radial distance from the axis between the radial distances of the inner and outer magnets. The magnetocaloric material is coupled to the shaft for rotation with the shaft about the axis such that during rotation of the shaft a portion of the magnetocaloric material alternates between a magnetized position disposed within the magnetic gap and a demagnetized position outside of the magnetic gap.

Claims

1. A magnetic refrigeration device for transferring heat, the magnetic refrigeration device comprising:

a shaft rotatable about an axis;

an inner magnet disposed at one of the axis and a radial distance from the axis;

an outer magnet disposed a radial distance from the axis outside of the inner magnet defining a magnetic gap between the inner and outer magnets; and

magnetocaloric material disposed at a radial distance from the axis between the radial distances of the inner and outer magnets, wherein the magnetocaloric material is coupled to the shaft for rotation with the shaft about the axis such that during rotation of the shaft a portion of the magnetocaloric material alternates between a magnetized position disposed within the magnetic gap and a demagnetized position outside of the magnetic gap.

2. The magnetic refrigeration device of claim 1, further comprising a fluid circuit that transfers fluid from a cold heat exchanger to the magnetocaloric material in the magnetized position, from the magnetocaloric material in the magnetized position to a hot heat exchanger, from the hot heat exchanger to the magnetocaloric material in the demagnetized position, and from the magnetocaloric material in the demagnetized position to the cold heat exchanger, wherein the cold heat exchanger is configured to absorb heat from a medium to be cooled, and wherein the hot heat exchanger is configured to reject heat.

3. The magnetic refrigeration device of claim 1, wherein the magnetocaloric material is contained in an annular container.

4. The magnetic refrigeration device of claim 3, wherein the annular container is divided into a plurality of channels extending axially, and wherein the annular container is coupled to the shaft for rotation with the shaft about the axis such that during rotation of the shaft at least a portion of each of the plurality of channels alternates between the magnetized position and the demagnetized position.

5. The magnetic refrigeration device of claim 4, wherein the plurality of channels is configured for bi-directional axial fluid flow therethrough.

6. The magnetic refrigeration device of claim 5, wherein one of the plurality of channels is configured for fluid flow therethrough in a first direction when the one of the plurality of channels is in the magnetized position, and wherein the one of the plurality of channels is configured for fluid flow therethrough in a second direction when the one of the plurality of channels is in the demagnetized position, wherein the first direction is opposite to the second direction.

7. The magnetic refrigeration device of claim 6, further comprising a rotary seal coupled to the annular container for rotation with the annular container, wherein the rotary seal includes a plurality of apertures, and wherein each one of the plurality of apertures is fluidly connected to a corresponding one of the plurality of channels.

8. The magnetic refrigeration device of claim 7, further comprising a stationary seal adjacent to the rotary seal, wherein the stationary seal is configured to be stationary and includes a plurality of slots in fluid communication with the plurality of apertures.

9. The magnetic refrigeration device of claim 8, wherein the plurality of slots includes a first slot in fluid communication with the portion of the plurality of channels in the magnetized position, and a second slot in fluid communication with the portion of the plurality of channels in the demagnetized position.

10. The magnetic refrigeration device of claim 9, wherein fluid flows through the first slot in the first direction, and wherein fluid flows through the second slot in the second direction.

11. The magnetic refrigeration device of claim 10, further comprising a fluid circuit configured to transfer fluid from a cold heat exchanger to the magnetocaloric material in the magnetized position, from the magnetocaloric material in the magnetized position to a hot heat exchanger, from the hot heat exchanger to the magnetocaloric material in the demagnetized position, and from the magnetocaloric material in the demagnetized position to the cold heat exchanger, wherein the cold heat exchanger is configured to absorb heat from a medium to be cooled, and wherein the hot heat exchanger is configured to reject heat.

12. The magnetic refrigeration device of claim 11, wherein the fluid circuit includes a pump configured to circulate a working fluid through the fluid circuit.

13. The magnetic refrigeration device of claim 1, further comprising an inner yoke coupled to the inner permanent magnet.

14. The magnetic refrigeration device of claim 13, wherein the inner yoke is coupled to the shaft by way of a bearing that allows the inner yoke to remain stationary as the shaft rotates.

15. The magnetic refrigeration device of claim 14, further comprising a stationary cylindrical outer yoke including a magnetic permeable material coupled to the outer permanent magnet

16. The magnetic refrigeration device of claim 1, wherein the outer magnet is configured to be stationary, wherein the inner magnet is coupled to the outer magnet by way of magnetic force, and wherein the inner magnet is substantially fixed relative to the outer magnet.

17. The magnetic refrigeration device of claim 1, wherein the magnetocaloric material is contained in a container configured for bi-directional fluid flow therethrough.

18. The magnetic refrigeration device of claim 17, wherein the container is configured for fluid flow in a first direction when the container is located in the magnetized position, and wherein the container is configured for fluid flow in a second direction when the container is located in the demagnetized position.

19. The magnetic refrigeration device of claim 1, wherein the magnetocaloric material is contained in a container configured for axial fluid flow therethrough.

20. A method of operating a magnetic refrigeration device to transfer heat, the method comprising:

rotating a shaft and a magnetocaloric material with the shaft about an axis; and

alternating a portion of the magnetocaloric material between a magnetized position disposed in a magnetic gap defined between an inner magnet disposed at one of the axis and a radial distance from the axis and an outer magnet disposed at a radial distance from the axis outside of the inner magnet, and a demagnetized position disposed outside of the magnetic gap.

21. The method of claim 20, further comprising moving a fluid through the magnetocaloric material in a first direction when the magnetocaloric material is in the magnetic gap and in a second direction when the magnetocaloric material is outside of the magnetic gap.

22. The method of claim 20, further comprising circulating a working fluid uni-directionally through a stationary portion including a hot heat exchanger configured to reject heat and a cold heat exchanger configured to absorb heat from a medium to be cooled, and circulating a working fluid bi-directionally through a rotary portion including the magnetocaloric material.

23. The method of claim 22, further comprising continuously circulating the working fluid through the hot heat exchanger and the cold heat exchanger during operation of the magnetic refrigeration device.

24. The method of claim 20, further comprising cooling a medium by circulating a working fluid from the portion of the magnetocaloric material outside of the magnetic gap to the cold heat exchanger and absorbing heat from the medium by way of the cold heat exchanger.

25. The method of transferring heat of claim 20, further comprising circulating a working fluid through the magnetocaloric material in a direction substantially parallel to the axis.

26. The method of transferring heat of claim 20, further comprising dividing the magnetocaloric material into a plurality of sections extending parallel to the axis.

27. The method of claim 20, further comprising continuously circulating a working fluid through the magnetocaloric material, through a hot heat exchanger configured to reject heat and through a cold heat exchanger configured to absorb heat from a medium to be cooled, during operation of the magnetic refrigeration device.

28. A method of operating a magnetic refrigeration device to transfer heat, the method comprising:

rotating a shaft about an axis;

coupling a first magnet to the shaft, allowing relative rotation therebetween;

magnetically coupling the first magnet with a stationary second magnet such that the first magnet substantially resists rotating with the shaft during rotation of the shaft;

rotating a magnetocaloric material with the shaft about the axis;

alternating a portion of the magnetocaloric material between a magnetized position disposed within a magnetic gap defined between the first magnet disposed at one of the axis and a radial distance from the axis and the second magnet disposed at a radial distance from the axis outside of the first magnet, and a demagnetized position outside of the magnetic gap; and

circulating a working fluid of a fluid circuit through the magnetocaloric material to cool a medium to be cooled.