PARALLEL MAGNETIC REFRIGERATOR ASSEMBLY AND A METHOD OF REFRIGERATING

• US 20110308258A1
• Filed: 01/29/2010
• Published: 12/22/2011
• Est. Priority Date: 01/30/2009
• Status: Active Grant

• Current Assignee: Technical University of Denmark
• Original Assignee: Technical University of Denmark
• Inventors: Smith, Anders, Bahl, Christian R.H., Pryds, Nini
• Granted Patent: US 9,528,728 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 2321/0021 with a static fixed magnet
• CPC Class Codes: Y02B 30/00 Energy efficient heating, ventilation or air conditioning [HVAC]

Abstract

A parallel magnetic refrigerator assembly, includes at least: a first magnetocaloric stage having in use a cold side and a hot side; a second magnetocaloric stage having in use a cold side and a hot side, arranged in parallel connection with the first magnetocaloric stage; the first and second magnetocaloric stages each including a hot side heat exchange circuit for carrying a heat exchange fluid to receive heat from the magnetocaloric stages and a cold side heat exchange circuit for carrying a heat exchange fluid to transfer heat to the magnetocaloric stages; wherein the hot side heat exchange circuit is configured such that in use a heat exchange fluid passes in thermal contact with the hot side of both the first and second magnetocaloric stages and the cold side heat exchange circuit is configured such that in use a heat exchange fluid passes in thermal contact with the cold side of both the first and second magnetocaloric stages. The first and second AMR stages have substantially the same temperature span but different cold end and hot end temperatures. In this way the device temperature span may be substantially larger than the individual temperature span of each AMR stage.

Claims

1. A magnetic refrigerator assembly, comprising:

a first magnetocaloric stage having a first temperature span arranged to receive a first heat transfer fluid for flow therein;

a second magnetocaloric stage having a second temperature span arranged to receive a second heat transfer fluid for flow therein arranged in parallel relationship to the first magnetocaloric stage;

wherein the first and second temperature spans are substantially the same but the absolute temperatures of the cold ends of the first and second magnetocaloric stages are different and/or the absolute temperatures of the hot ends of the first and second magnetocaloric stages are different.

2. A magnetic refrigerator assembly according to claim 1, in which, in use, each of the first and second magnetocaloric stages have a respective cold side and hot side;

each of the first and second magnetocaloric stages including a hot side heat exchange circuit.

3. An assembly according to claim 2, in which the hot side heat exchange circuit is configured such that in use a heat exchange fluid passes first in thermal contact with the hot side of the first magnetocaloric stage and then in thermal contact with the hot side of the second magnetocaloric stage, wherein, in use, the temperature of the hot side of the first magnetocaloric stage is lower than that of the hot side of the second magnetocaloric stage.

4. An assembly according to claim 1, further comprising, a hot side heat exchanger for connection to the hot side heat exchange circuit and a cold side heat exchanger for connection to the cold side heat exchange circuit.

5. An assembly according to claim 1, in which the cold side heat exchange circuit is configured such that the heat exchange fluid passes in thermal contact with the cold side of both the first and second magnetocaloric stages.

6. An assembly according to claim 1, in which more than two parallel magnetocaloric stages are provided.

7. An assembly according to claim 6, in which each of the magnetocaloric stages comprises a magnetocaloric unit and a magnetic field source to selectively magnetise and demagnetise the magnetocaloric unit.

8. An assembly according to claim 1, comprising one or more pumps to pump heat transfer fluid through the magnetocaloric units in cycle with the magnetising and demagnetising thereof to achieve an active magnetic regeneration cycle.

9. An assembly according to claim 1, in which each of the magnetocaloric units comprises a magnetocaloric element having therein plural discrete paths for the flow of heat transfer fluid in reciprocating or rotating motion between a hot end and cold end in use.

10. An assembly according to claim 1, in which the temperature span of each of the first and second magnetocaloric stages is between 10 and 60°

C.

11. An assembly according to claim 1, in which the temperature offset between each stage is between 0.5 and 5°

C.

12. An assembly according to claim 1, in which the total span of the hot side and the total span of the cold side are different.

13. A parallel magnetic refrigerator assembly, comprising:

a first magnetocaloric stage having in use a cold side and a hot side;

a second magnetocaloric stage having in use a cold side and a hot side, arranged in parallel connection with the first magnetocaloric stage;

the first and second magnetocaloric stages each including a hot side heat exchange circuit for carrying a heat exchange fluid to receive heat from the magnetocaloric stages and a cold side heat exchange circuit for carrying a heat exchange fluid to transfer heat to the magnetocaloric stages;

wherein the hot side heat exchange circuit is configured such that in use a heat exchange fluid passes successively in thermal contact with the hot side of both the first and second magnetocaloric stages.

14. An assembly according to claim 13, in which the hot side heat exchange circuit is configured such that in use a heat exchange fluid passes first in thermal contact with the hot side of the first magnetocaloric stage and then in thermal contact with the hot side of the second magnetocaloric stage, wherein, in use, the temperature of the hot side of the first magnetocaloric stage is lower than that of the hot side of the second magnetocaloric stage.

15. An assembly according to claim 13 further comprising, a hot side heat exchanger for connection to the hot side heat exchange circuit and a cold side heat exchanger for connection to the cold side heat exchange circuit.

16. An assembly according to claim 13, in which the operating temperatures of the cold side of each of the first and second magnetocaloric stages are different and the operating temperatures of the hot side of each of the first and second magnetocaloric stages are also different such that the temperature span of each of the first and second magnetocaloric stages is substantially the same.

17. An assembly according to claim 13, in which each of the magnetocaloric units comprises a magnetocaloric element having therein plural discrete paths for the flow of heat transfer fluid in reciprocating motion between a hot end and cold end in use.

18. A method of refrigeration or heat pumping, the method comprising in a magnetic refrigerator assembly having first and second magnetocaloric stages arranged in parallel with repsective first and second temperature spans:

providing a first heat transfer fluid and causing said first heat transfer fluid to flow in the first magnetocaloric stage;

providing a second heat transfer fluid and causing said second heat transfer fluid to flow in the second magnetocaloric stage;

wherein the first and second temperature spans are substantially the same but the absolute temperatures of the cold ends of the first and second magnetocaloric stages are different and/or the absolute temperatures of the hot ends of the first and second magnetocaloric stages are different.