FLOW-SYNCHRONOUS FIELD MOTION REFRIGERATION

• US 20120222427A1
• Filed: 09/17/2010
• Published: 09/06/2012
• Est. Priority Date: 09/17/2009
• Status: Active Grant

• Current Assignee: Charles N Hassen
• Original Assignee: Materials and Electrochemical Research Corporation
• Inventors: Hassen, Charles N.
• Granted Patent: US 9,739,510 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 2321/001 by using electro-caloric effects
• CPC Class Codes: F25B 2321/002 by using magneto-caloric effects
• CPC Class Codes: F25B 30/00 Heat pumps F25B1/00-F25B25/00, F25B29/00 take precedence
• CPC Class Codes: Y02B 30/00 Energy efficient heating, ventilation or air conditioning [HVAC]
• CPC Class Codes: Y02B 30/52 Heat recovery pumps, i.e. heat pump based systems or units able to transfer the thermal energy from one area of the premises or part of the facilities to a different one, improving the overall efficiency

Abstract

An improved method to manage the flow of heat in an active regenerator in magnetocaloric or an electrocaloric heat-pump refrigeration system, in which heat exchange fluid moves synchronously with the motion of a magnetic or electric field. Only a portion of the length of the active regenerator bed is introduced to or removed from the field at one time, and the heat exchange fluid flows from the cold side toward the hot side while the magnetic or electric field moves along the active regenerator bed.

Claims

1. In a method for operating a heat pump comprising pumping heat exchange fluid through an active magnetocaloric or electrocaloric regenerator from a cold end to a hot end of said regenerator, said regenerator comprising magnetocaloric or electrocaloric regenerator material encased within a housing and having at least one magnetic or electric field source positioned exterior of said housing so as to act upon said regenerator material and thereby increase the temperature thereof and, in turn, the temperature of said heat exchange fluid passing therethrough, the improvement wherein:

(a) said field source of a length less than or equal to the length of said regenerator moves lengthwise relative to said regenerator, or vice versa, with said field source acting upon only a portion of said regenerator material at one time, so as to subject said regenerator material to changing fields and thereby produce corresponding changes in the temperature of said regenerator material and said heat exchange fluid passing therethrough; and

(b) said heat exchange fluid is pumped through said regenerator in synchronous flow with said relative motion of said field source;

the combination of said relative motion of said field source and said synchronous flow of said heat exchange fluid enabling improved management of heat flow through said regenerator.

2. The method of claim 1 in which said heat exchange fluid is pumped at a rate providing a non-zero fluid velocity that exceeds the moving field source translational velocity, and thereby providing a forward bias to said synchronous flow, so that changes in temperature of the heat exchange fluid accumulate hot heat exchange fluid in front of the moving field source, and cold heat exchange fluid on the trailing edge of the moving field source.

3. The method of claim 1, in which said heat exchange fluid is pumped at a rate providing a non-zero fluid velocity that is approximately equal to the moving field source translational velocity, and thereby providing a neutral bias to said synchronous flow, so that changes in temperature of the heat exchange fluid accumulate hot heat exchange fluid near the leading edge of the moving field source, and cold heat exchange fluid behind the trailing edge of the moving field source.

4. The method of claim 1, in which said heat exchange fluid is pumped at a rate providing a non-zero fluid velocity that is slower than the moving field source translational velocity, and thereby providing a negative bias to said synchronous flow, so that changes in temperature of the heat exchange fluid accumulate hot heat exchange fluid in a zone trailing the leading edge of the moving field source, and accumulate cold heat exchange fluid in a zone on the trailing edge of the moving field source.

5. The method of claim 1, in which said field source is of a length less than the length of said regenerator.

6. The method of claim 1, in which the heat exchange fluid moves in small incremental steps executed sequentially in between small incremental steps in the position of the field source along the regenerator.

7. The method of claim 1, in which the heat exchange fluid is water, or a combination of water and another material, such as alcohol or antifreeze, introduced to extend the useful range of temperatures over which said heat pump may be applied.

8. The method of claim 1, in which said regenerator is a magnetocaloric regenerator, said regenerator material is magnetocaloric material, and said field source is a permanent magnet or an electromagnet providing a magnetic field.

9. The method of claim 8, in which the magnetocaloric material is gadolinium.

10. The method of claim 8, in which the magnet moves in rotary motion relative to a circularly configured regenerator comprising at least one segment arranged as a partial ring with a center of curvature coincident with the axis about which the relative rotary motion occurs, or in which the regenerator moves in rotary motion relative to the magnet.

11. The method of claim 8, in which said magnet moves in linear motion relative to a linearly configured regenerator comprising at least one segment, or in which the regenerator moves in linear motion relative to the magnet.

12. The method of claim 1, in which said regenerator is an electrocaloric regenerator, said regenerator material is electrocaloric material, and said field source is an electrode or a series of electrodes providing an electric field.

13. The method of claim 12, in which the electrocaloric material is a ferroelectric polymer.

14. The method of claim 12, in which said electric field is established by means of a multiplicity of electrically and physically isolated electrodes, each of which is independently switchable.

15. The method of claim 1, in which said heat pump includes a cold-side heat exchanger adjacent the cold end of said regenerator and a hot-side heat exchanger adjacent the hot end of said regenerator;

said heat exchange fluid is pumped through said regenerator cyclically and reversibly in a forward stage from said cold end to said hot end and a reverse stage from said hot end to said cold end of said regenerator;

said relative motion of said field source and said synchronous flow of said heat exchange fluid are applied to the system during the forward stage only of each cycle;

the forward stage of each cycle delivers a heated volume of heat exchange fluid to said hot-side heat exchanger; and

the reverse stage of each cycle delivers a cooled volume of heat exchange fluid to said cold-side heat exchanger.

16. The method of claim 15, in which the heat pump operates as a refrigerator by pumping heat from a load on the cold side to a heat sink on the hot side of the heat pump.

17. The method of claim 15, in which the heat pump operates as a heater by pumping heat from a cold side heat source to a load on the hot side of the heat pump.

18. The method of claim 1, in which said regenerator has a fluid input end and a fluid output end;

said heat pump includes a fluid control valve at said fluid output end of said regenerator; and

said heat exchange fluid is pumped through said regenerator continuously from the fluid input end to the fluid output end of said regenerator;

whereby the combination of said relative motion of said field source and said synchronous flow of said heat exchange fluid develops a mass of hot heat exchange fluid moving near the front end of said field source and a mass of cold heat exchange fluid moving near the trailing end of said field source as said field source progresses from the input side toward the output side of said regenerator, such that when said field source reaches the output end of said regenerator, the synchronously moving heat exchange fluid carries first a hot pulse and then a cold pulse of fluid, with the centroids of said hot and cold pulses physically separated from one another in the stream of heat exchange fluid emerging from the output end of said regenerator;

such that said fluid control valve may direct the flow of fluid in the hot pulse to a different location from the flow of fluid in the cold pulse;

thereby allowing said heat pump to act as a refrigerator or as a heater depending on the application requirements.