REFRIGERATION DEVICE AND A METHOD OF REFRIGERATING

• US 20110239662A1
• Filed: 07/15/2008
• Published: 10/06/2011
• Est. Priority Date: 08/17/2007
• Status: Active Grant

• Current Assignee: Technical University of Denmark
• Original Assignee: Technical University of Denmark
• Inventors: Kuhn, Luise T., Bahl, Christian R.H., Smith, Anders, Pryds, Nini, Linderoth, Soren
• Granted Patent: US 8,448,453 B2
• Time in Patent Office: Days
• US Class Current: 62/3.1
• CPC Class Codes: F25B 21/00 Machines, plants or systems, using electric or magnetic effects
• CPC Class Codes: F25B 2321/002 by using magneto-caloric effects
• CPC Class Codes: F25B 2321/0023 with modulation, influencing or enhancing an existing magnetic field
• CPC Class Codes: Y02B 30/00 Energy efficient heating, ventilation or air conditioning [HVAC]

Abstract

The invention provides a refrigeration device, comprising: a magnetic field source; a magnetocaloric bed, one of the magnetocaloric bed and the magnetic field source being arranged to substantially surround the other, the magnetocaloric bed being arranged for relative rotation with respect to the magnetic field source such that during said relative rotation, the magnetic field experienced by parts of the magnetocaloric bed varies; plural pathways formed within the magnetocaloric bed for the flow of a working fluid during the relative rotation between the magnetocaloric bed and the permanent magnet; and a flow distributor placed at each end of the magnetocaloric bed, for controlling the part of the magnetocaloric bed able to receive working fluid during a cycle of operation.

Claims

1. A refrigeration device, comprising:

a magnetic field source;

a magnetocaloric bed, one of the magnetocaloric bed and the magnetic field source being arranged to substantially surround the other, the magnetocaloric bed being arranged for relative rotation with respect to the magnetic field source such that during said relative rotation, the magnetic field experienced by parts of the magnetocaloric bed varies;

plural pathways formed within the magnetocaloric bed for the flow of a working fluid during the relative rotation between the magnetocaloric bed and the permanent magnet; and

a flow distributor placed at each end of the magnetocaloric bed, for controlling the part of the magnetocaloric bed able to receive working fluid during a cycle of operation.

2. A refrigeration device according to claim 1, in which each flow distributor has at least two openings and is fixed with respect to the magnetic field source such that as the magnetocaloric component moves relative to the flow distributors, the part of the magnetocaloric bed exposed to the openings changes.

3. A refrigeration device according to claim 1 or 2, in which the magnetocaloric bed is cylindrical in form.

4. A refrigeration device according to any of claims 1 to 3, in which the magnetic field source includes at least one permanent magnet.

5. A refrigeration device according to any of claims 1 to 4, in which the magnetic field source is arranged within the magnetocaloric bed such that the magnetocaloric bed rotates around the magnetic field source.

6. A refrigeration device according to any of claims 1 to 5, in which the magnetic field source has a shape such as to cause the variation in magnetic field during the relative rotation between the magnetic field source and the magnetocaloric bed.

7. A refrigeration device according to any of claims 1 to 6, in which the pathways within the magnetocaloric bed are substantially parallel to the longitudinal axis of the magnetocaloric bed.

8. A refrigeration device according to claim 7, in which the magnetocaloric bed is made up of plural radially spaced plates of magnetocaloric material such that the pathways are defined by gaps between adjacent pairs of plates.

9. A refrigeration device according to any of claims 1 to 8, in which the magnetic ordering temperature of the magnetocaloric bed varies along the length of device.

10. A refrigeration device according to claim 9, further comprising flowguides fixedly mounted to the magnetocaloric bed between the magnetocaloric bed and the flow distributors to ensure steady laminar flow of working fluid into the bed through the openings in the flow distributors.

11. A refrigeration device according to any of claims 1 to 10, in which the magnetic field source is made up of plural long permanent magnet segments each covering an arc on the inner surface of the cylindrical magnetocaloric bed.

12. A refrigeration device according to any of claims 1 to 11, comprising a yoke arranged with respect to the magnetocaloric component to act as a return path for magnetic flux.

13. A refrigeration device according to claim 12, in which the yoke contains at least one permanent magnet.

14. A refrigeration device according to any of claims 1 to 13, in which the angular size of the openings is selected to define the AMR cycle characteristics.

15. A refrigeration device according to any of claims 1 to 14, in which the width of the plural pathways of the magnetocaloric bed varies along the radial direction.

16. A refrigeration device according to any of claims 1 to 15, in which the surface of the plural pathways is uneven.

17. A refrigeration device according to claim 16, in which the surface of the plural pathways is corrugated or knobbed.

18. A refrigeration device according to any of claims 1 to 17, comprising a hot side heat exchanger and a cold side heat exchanger connected to respective ends of the device.

19. A refrigeration device according to claim 18, in which the heat exchangers are arranged such that the cold end is kept in contact with the surroundings and the hot end is used to heat whereby the device operates as heat pump.

20. A refrigeration device according to claim 18, in which at least one of the heat exchangers is integrated in one of the flow distributors.

21. A refrigeration device according to any of claims 1 to 20, in which the magnetocaloric bed and the magnetic field source are arranged substantially coaxially, the magnetic field source being arranged within the cylinder of the magnetocaloric bed.

22. A refrigeration device according to any of claims 1 to 21, in which the magnetocaloric bed and the magnetic field source are arranged substantially coaxially, the magnetocaloric bed being arranged within the magnetic field source.

26. A method according to any of claims 23 to 25, in which the method is executed using a refrigeration device according to any of claims 1 to 22.

23. A method of refrigeration, the method comprising:

providing a magnetic field source and a magnetocaloric bed, one surrounding the other and being arranged for relative rotation;

providing a flow distributor at each end of the magnetocaloric bed for controlling the part of the magnetocaloric bed able to receive working fluid during a cycle of operation;

forcing a liquid refrigerant to flow through the flow distributors and the magnetocaloric bed as the magnetic field source and the magnetocaloric bed rotate relative to each other to thereby cause the fluid to be heated or cooled.

24. A method according to claim 23, comprising:

providing in communication with one end of the magnetocaloric bed a hot side heat exchanger to remove heat from the heated fluid, and

providing in communication with the other end of the magnetocaloric bed a cold side heat exchanger to absorb heat from the environment.

25. A method according to claim 23 or 24, in which the fluid is forced into or out of the magnetocaloric bed in the same direction with respect to the common axis, irrespective of the stage of the AMR cycle at which the fluid is actually moving.