Thermal generator with magnetocaloric material and incorporated heat transfer fluid circulation means

• US 8,869,541 B2
• Filed: 10/17/2008
• Issued: 10/28/2014
• Est. Priority Date: 10/30/2007
• Status: Active Grant

• Current Assignee: Magnoric
• Original Assignee: Cooltech Applications S.A.S.
• Inventors: Heitzler, Jean-Claude, Muller, Christian
• Primary Examiner(s): Tyler, Cheryl J
• Assistant Examiner(s): ARANT, HARRY E
• Application Number:
  US12/682,899
• Publication Number:
  US 20100236258A1
• Time in Patent Office: 2,202 Days
• Field of Search: 62/31, 626/30, 623/35, 624/42, 62/33, 62/6, 92/71, 605/17, 165/104.19, 219/623, 219/618, 417/415, 417/269
• 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 2321/0022 with a rotating or otherwise moving magnet
• CPC Class Codes: Y02B 30/00 Energy efficient heating, ventilation or air conditioning [HVAC]

Abstract

A heat generator (1) having at least one thermal module (10) that has N adjacent magnetocaloric elements (2) arranged in a circle around a central axis (A) and is subjected to a varying magnetic field caused by magnetic devices (3). The magnetocaloric elements (2) are associated with N pistons (40) subjected to a reciprocating translation movement by an actuating cam (70) to circulate the heat transfer fluid, contained in the thermal module (10), in two opposite directions, at the same time, so that a first fraction of the heat transfer fluid circulates towards a hot exchange chamber (5), through the magnetocaloric elements (2) and is subjected to a heating cycle, and a second fraction of the heat transfer fluid circulates towards a cold exchange chamber (6), through the magnetocaloric elements (2), and is subjected to a cooling cycle, and inversely. The exchange chambers (5, 6) are coupled with external circuits that use calories and frigories for heating, air-conditioning, tempering systems, etc.

Claims

1. A heat generator (1, 100) comprising magnetocaloric elements (2) and magnetic devices (3) arranged to alternately subject the magnetocaloric elements (2) to a variation in a magnetic field and alternately create, in each magnetocaloric element (2), a heating cycle and a cooling cycle,

at least one heat transfer fluid arranged to collect at least one of heat energy (calories) and cold energy (frigories) produced by the magnetocaloric elements (2) during the heating and cooling cycles,

at least one hot exchange chamber (5) and one cold exchange chamber (6) respectively placed at hot and cold ends of the heat generator (1, 100),

means for circulating (4) the heat transfer fluid between the magnetocaloric elements (2) and the hot and cold exchange chambers (5, 6),

the heat generator comprising at least one thermal module (10-13) comprising at least one set of a number of adjacently arranged magnetocaloric elements (2), and

the means for circulating (4) being synchronized with the variation in magnetic field and being arranged to alternately circulate the heat transfer fluid inside the thermal module (10-13) in two opposite directions at the same time, between the hot (5) and cold (6) exchange chambers through the magnetocaloric elements (2), so that a first fraction of the heat transfer fluid circulates towards the hot exchange chamber (5), through the magnetocaloric elements (2) subjected to a heating cycle, and a second fraction of the heat transfer fluid circulates towards the cold exchange chamber (6) through the magnetocaloric elements (2) subjected to a cooling cycle, and inversely,

wherein the means for circulating (4) are arranged to displace the heat transfer fluid between the hot (5) and cold (6) exchange chambers in a reciprocating movement, and comprise

at least a same number of pistons (40) as the number of adjacently arranged magnetocaloric elements (2),

the pistons (40) are positioned opposite the magnetocaloric elements (2), and

the pistons (40) are subjected to a reciprocating translation movement by a driving mechanism (7) that comprises at least one actuating cam (70) driven by an actuator.

2. The heat generator according to claim 1, wherein an actuating cam (70) comprises a cam profile (71) which has a sinusoidal shape, an amplitude of which determines a stroke of the pistons (40) and a sinusoidal phase of which corresponds to a heating cycle and a cooling cycle of the magnetocaloric elements (2).

3. The heat generator according to claim 2, wherein each couple formed by a magnetized zone (ZA) and a non magnetized zone (ZN) extends over a distance that corresponds to a sinusoid of the cam profile (71).

4. The heat generator according to claim 1, wherein the means for circulating (4) comprise at least twice the number of pistons (40), positioned on each side of the magnetocaloric elements (2), as the number of adjacently arranged magnetocaloric elements (2).

5. The heat generator according to claim 1, wherein the magnetocaloric elements (2) comprise emerging fluid passages, which are formed from one of pores, channels, and grooves.

6. The heat generator according to claim 1, wherein the magnetic devices (3) comprise at least one magnetic arrangement (30), formed of alternate magnetized zones (ZA), and non magnetized zones (ZN), in a vicinity of the magnetocaloric elements (2), the magnetic arrangement (30) is coupled with the actuator so as to be mobile in relation to the magnetocaloric elements (2).

7. The heat generator according to claim 6, wherein the magnetic devices (3) comprise a field closing device (31), positioned opposite the magnetic arrangement (30), for closing the magnetic flux generated by the magnetized zones (ZA) through the magnetocaloric elements (2).

8. The heat generator according to claim 6, wherein each magnetized zone (ZA) comprises at least two permanent magnets (32), which have opposite polarities, assembled on a core (33) with high magnetic permeability so as to concentrate the magnetic flux of the magnets towards the magnetocaloric elements (2).

9. The heat generator according to claim 6, wherein the thermal module (10-13) has a circular structure in which the magnetocaloric elements (2) are arranged in a circle around a central axis (A), and the actuating cam (70) and the magnetic arrangement (30) are concentric with this central axis (A) and for rotation around the axis (A).

10. The heat generator according to claim 1, wherein

the heat generator comprises X number of thermal modules (10-13) stacked to form the heat generator with a same X number of thermal stages, and

the thermal modules (10-13) are assembled in pairs using intermediate chambers (8).

11. The heat generator according to claim 10, wherein the intermediate chambers (8) communicate with the pistons (40) and form heat transfer fluid mixing chambers between two consecutive thermal modules (10-13).

12. The heat generator according to claim 10, wherein the intermediate chambers (8) do not communicate with the pistons (40), as the heat transfer fluid passes from one thermal module (10-13) to another via the magnetocaloric elements (2).

13. The heat generator according to claim 10, wherein the pistons (40) of two consecutive thermal modules (10-13) are shared.

14. The heat generator according to claim 1, wherein the hot exchange chamber and the cold exchange chamber are each connected to an external circuit fitted with a device that allows heat exchange only after reaching a predefined temperature inside the exchange chamber in question.

15. The heat generator according to claim 1, wherein the heat transfer fluid is monophasic fluid.