FR2930679A1 - Thermal flow generating device, has electric coils supplied with electric current for generating variation of magnetic field to displace mobile assembly carrying magnetic arrangement, and thermal unit placed between coils and arrangement - Google Patents

Abstract

The device (10) has an electric drive e.g. linear motor, for displacing a magnetic arrangement with respect to magnetocaloric elements (13) for subjecting the arrangement to magnetic field variation and provoking variation of temperature of the arrangement. The drive has electric coils (14) supplied with the electric current for generating variation of the magnetic field to displace a mobile assembly carrying the arrangement. A thermal unit containing the magnetocaloric elements is placed between the electric coils and the arrangement. Each coil has a winding carried by an armature (16).

Description

DEVICE FOR GENERATING THERMAL FLOW WITH MAGNETOCALORIC MATERIAL

Technical Field: The present invention relates to a thermal flux generation device magnetocaloric material having at least one thermal flow generation unit provided with at least one thermal member containing at least one magnetocaloric element, at least one magnetic arrangement arranged to generate a magnetic field, at least one electrical drive arranged to ensure the displacement of said magnetic arrangement with respect to said magnetocaloric element in order to subject it to a magnetic field variation and cause a variation of its temperature, means for capturing calories and / or frigories emitted by said magnetocaloric element due to said variation of the magnetic field.

Prior Art: The publication WO-A-03/050456 describes a magnetic refrigeration device magnetocaloric material using two permanent magnets and having a monobloc annular enclosure delimiting compartments magnetocaloric material, for example gadolinium in porous form, these compartments being: separated by joints. Each compartment is provided with at least four orifices, one inlet port and one outlet port connected to a hot circuit and one inlet port and one outlet port connected to a circuit cold. The two permanent magnets are animated by a continuous rotation movement so that they successively scan the different compartments with fixed magnetocaloric materials and subject them to variations in the magnetic field. The calories and / or frigories emitted by the magnetocaloric material are captured by the hot and cold heat transfer fluid circuits and directed towards heat exchangers. The permanent magnets are rotated by an electric motor which also drives rotary joints so that the coolant conduit passing through the fixed magnetocaloric material compartments is successively connected to the hot and cold circuits. This device, which thus simulates the operation of a liquid ring, requires precise and synchronous continuous rotation of the different rotary joints and permanent magnets.

The displacement, in particular the linear drive or the rotary drive, of the magnets which generate the magnetic field whose variation, due to the linear or rotary displacement, causes the temperature cycles of the magnetocaloric materials, requires motor means which are usually constituted of a conventional electric motor. It will be noted that conventional magnetocaloric materials have the effect of heating up almost instantaneously when they enter a magnetic field. The so-called inverse magnetocaloric materials have the particularity to cool as they enter a magnetic field. The generation of calories or of negative calories called frigories has different interests depending on the applications envisaged. The motor that causes the magnets to move has a certain bulk which adds to the size of the device and increases its cost, weight and volume and reduces its efficiency, which is a set of disadvantages that penalize the development of this technology, especially to generate cold, despite the indisputable ecological interest of the solution.

SUMMARY OF THE INVENTION The present invention proposes to overcome these drawbacks by producing a heat flux generating device of magnetocaloric material, which is economical and compact, all components of which are arranged in order to obtain an optimized construction in a minimum volume with optimum energy efficiency. This object is achieved by the device of the invention, as defined in the preamble, characterized in that said electric drive is integrated with the thermal flux generation device magnetocaloric material and comprises at least two electrical windings powered by electrical current so generating a magnetic field variation which causes displacement of a movable assembly carrying said magnetic arrangement and in that said thermal member containing said magnetocaloric element is disposed between said electrical windings and said magnetic arrangement. This solution makes it possible, by a direct control of these electric windings, to ensure the displacement of said magnetic arrangement and, in particular when the magnetic field is obtained by permanent magnets, to cooperate with these. permanent magnets to optimize the energy efficiency of the magnetocaloric material in the magnetic field by means of these electric windings. According to a first embodiment, when said electric drive is a rotary motor, the device comprises a peripheral carcass, a stator housed in this carcass and a rotor mounted inside said carcass coaxially with said stator, said rotor carrying said magnetic arrangement and said magnetocaloric element being disposed in the air gap between said rotor and said stator. According to another embodiment, when said electric drive is a linear motor, the device comprises an elongate carcass, a fixed linear stator and a carriage movable alternately with respect to said stator and carrying said magnetic arrangement iet said magnetocaloric element being disposed in the air gap between said linear stator and said movable carriage.

Said rotor is advantageously composed of at least one magnetic arrangement which may, for example comprise permanent magnets.

According to a particularly advantageous embodiment, said magnetic arrangement of said movable carriage comprises a set of permanent magnets.

Said permanent magnets of said magnetic arrangement of said rotor advantageously comprise at least one magnetically permeable element.

Said permanent magnets of the magnetic arrangement of said movable carriage advantageously comprise at least one magnetically permeable element.

When said motor is of the rotary type, the device preferably comprises at least one ring of magnetocaloric elements surrounding said rotor and disposed in the gap between said stator and said rotor. When said motor is of the linear type, the device preferably comprises at least one row of magnetocaloric elements aligned along at least a portion of the fixed linear stator in the gap between said linear stator and said moving carriage. When said motor is of the rotary type, said stator advantageously comprises a set of electric windings each having an axis disposed in a substantially radial direction.

When said motor is of linear type, said fixed linear stator advantageously comprises a set of electric windings having axes parallel and substantially perpendicular to the direction of movement of said movable carriage.

According to a particularly advantageous embodiment, each of said electrical windings comprises a winding carried by a T-shaped frame and comprising a base piece and a branch perpendicular to the base piece.

Said armature may be made of one of the materials selected from the group consisting of soft iron, an alloy of iron and cobalt (FeCo), an alloy of iron and silicon (FeSi). Said magnetic arrangement preferably comprises at least one magnetic flux concentrator. Said magnetic flux concentrator is preferably made of one of the materials selected from the group consisting of soft iron, an alloy of iron and cobalt (FeCo), an alloy of iron and silicon (FeSi). According to another embodiment, said magnetic flux concentrator is made of stacked sheets.

Advantageously, said set of electric windings has a geometrical asymmetry with respect to the flux lines generated by said magnetic arrangement to impose a preferred direction of rotation on said rotor.

Advantageously, said set of electric windings has a geometrical asymmetry with respect to the flux lines generated by said magnetic arrangement to impose a preferred direction of linear motion to said movable carriage.

The device may comprise means for driving said electric windings, these means comprising at least one electronic circuit arranged for sequentially switching said electric windings.

Brief description of the drawings: The present invention and its advantages will appear better in the following description of several embodiments, given by way of non-limiting example with reference to the accompanying drawings, in which:

FIG. 1 is a perspective view of a first embodiment of the device of the invention,

FIG. 2 is a plan view of the device of FIG. 1,

FIGS. 3A and 3B are sectional views along lines A-A and B-B, respectively, of FIG. 2;

FIG. 4 is a perspective view of a second embodiment of the device of the invention, FIG. 5 is a partial perspective view of the device of FIG. 4, FIG. 6 is a plan view of FIG. an alternative embodiment of the device according to the invention,

FIGS. 7A, 7B and 7C show a first embodiment of the device of the invention in which the motor is of the linear type, and

FIGS. 8A, 8B and 8C show a second embodiment of the device of the invention in which the motor is linear. Different ways of carrying out the invention:

With reference to FIGS. 1 to 3, the device 10 shown, which corresponds to a particular embodiment variant of substantially cylindrical geometry, comprises a cylindrical external carcass 11, made of metal or any other suitable material, which delimits the internal space of the device 10. Inside this carcass 11 are mounted a rotor 12 which consists of a rotating magnetic arrangement which will be described in more detail later, at least one thermal member constituted in this case of a ring substantially circular element 13 comprising at least one magnetocaloric material, this ring being arranged coaxially around said rotor 12 and a set of electric windings 14, radial axes, regularly arranged around said rotor 12 and constituting a stator 15. The elements 13 comprising at least one magnetocaloric material are arranged in the circular air gap separating the rotor 12 from the stator 15.

The rotating magnetic arrangement of said rotor 12 as shown, comprises a plurality of permanent magnets 17, in this case eight in number, separated by elements 18 of soft iron or the like, in this case also eight in number, which is. The assembly is mounted in a radial geometry, the permanent magnets 17 all having the same shape and the elements 18 of soft iron or the like, such as for example an iron-cobalt alloy (FeCo) or a iron-silicon alloy (FeSi), having two by two the same geometrical shape and being regularly interposed between the permanent magnets 17. This provision is not binding and it is possible to modify both the shape and the number and arrangement of the components of the magnetic arrangement. The purpose of this magnetic arrangement is to achieve the most intense magnetic field, in a relatively small space and at the lowest possible construction cost. The magnetic field generates field lines which pass through the magnetocaloric elements 13 and is variable as a function of the rotation of the rotor 12, so as to generate, in a manner known per se, thermal variations in said magnetocaloric elements 13. Magnetocaloric elements 13 are shown schematically in the form of cylindrical bars, but their shape and their structure may be different. The magnetocaloric material (s) used may for example be composed of a porous structure, structured elements, peripheral coating of tubular parts or the like. It is essential that the contact surface of the magnetocaloric elements with a heat transfer fluid is as large as possible so that heat exchange can be carried out under the best conditions with the greatest efficiency.

In known magnetocaloric effect heat flux generating devices of this type, the rotor 12 is driven by an independent, external electric motor coupled to the rotor. In the present embodiment, the motorized movement or drive is generated by means of available components, by using the existing permanent magnets 17 and by associating them, for example as in the variant illustrated, with eight electric windings 14 each comprising an electric winding 14a. each armature 16 has substantially the shape of a T and comprises a circular sector-shaped base piece 16a and a branch 16b perpendicular to the base piece 16a. The interaction of the electromagnetic field created by the selectively energized electric windings 14 produces, on the permanent magnets 17, a torque which produces the displacement, in this case the rotation of the rotor 12. Consequently, the addition of the electric windings 14 makes it possible to combining the driving function of the rotor 12 with the basic function of the thermal flux generation device 10 of magnetocaloric material, consisting in creating alternating variations of the magnetic field in order to cause temperature fluctuations within the elements 13 of material magnetocaloric.

As shown in FIG. 2, in the example represented by eight electric windings 141, 142, 143, 144, 145, 146, 147, and 148, means are used for driving said electric windings, for example an electronic circuit 30, schematically illustrated, and connecting elements 31. Sequential power is supplied to said electric windings in order to create positive magnetic poles (+) in the first place at base parts 161a and 165a of the armatures 161 and 165 corresponding respectively to the electrical windings 141 and 145, and negative magnetic poles (-) at the base parts 163a and 167a of the armatures 163 and 167 respectively corresponding to the electric windings 143 and 147. In a second step, the power supply of the windings in such a way that positive (+) magnetic poles are created at the base parts 162a and 166a of the armatures 162 and 166 respectively corresponding to the bob electrical inages 142 and 146 and negative magnetic poles (-) at the base parts 164a and 168a of the armatures 164 and 168 respectively corresponding to the electric windings 144 and 148. This process makes it possible to produce a rotating field necessary to drive the rotor 12 Advantageously, a slight asymmetry in the radial arrangement of the coils will initiate a preferred direction of rotation.

FIGS. 3A and 3B respectively represent views of the device of FIGS. 1 and 2 cut along the lines A-A and B-B illustrating the arrangement of the windings of the electric windings 14 and of the components of the armature 16 in particular of the radially arranged arm 16b.

FIG. 4 is a view similar to that of FIG. 1 showing a construction in which the device 20 is equipped with sixteen electric windings 24 housed inside a cylindrical carcass 21 and constituting the stator 25. The motorized drive is similar to the previous one and the rotor 22 is substantially identical to the rotor 12. The same is true of the ring of elements 23 comprising at least one magnetocaloric material which is disposed in the air gap which separates the rotor 22 from the stator 25. increasing the number of electrical windings makes it possible to drive the rotating field more progressively and to better control the rotational drive of the rotor 22.

Figure 5 is a view similar to that of Figure 4, but the peripheral cylindrical housing 21 has been removed. FIG. 6 shows another embodiment in which the carcass has been removed, which differs from that of FIG. 2, principally in that the permanent magnets 17 of the magnetic arrangement are replaced by electromagnets 120 which equip the rotor 12. The device 100 comprises in this case a set of seventeen electrical coils 14, radial axes, regularly placed around said rotor 12 and constituting a stator 15. The number of electromagnets 120 is in this case eighteen, so that the electric windings 14 have compared with the electromagnets 120 a geometrical asymmetry, in this case an axial offset of a few degrees with respect to the corresponding electric windings 14 to impose the rotor a preferred direction of rotation.

FIGS. 7A, 7B and 7C correspond to a first embodiment of the device of the invention in which the drive of the magnetic arrangement is effected by linear displacement. The device 50 comprises an elongate carcass not shown, a fixed linear stator 51 and a carriage 52 movable alternately with respect to said fixed linear stator 51 and carrying said magnetic arrangement, in this case composed of a series of permanent magnets 53, each associated with to a magnetically permeable element 54. The fixed linear stator 51 consists of a set of electric windings 55 with axes parallel and perpendicular to the direction of movement of the carriage 52. A series of magnetocaloric elements 56 is aligned along at least a portion of the linear stator. fixed, in the gap between said fixed linear stator 51 and said magnetic arrangement, or more exactly the line of magnetically permeable elements 54.

The three figures 7A, 7B and 7C correspond to three successive positions of the carriage 52 moving linearly during its displacement. The field lines which pass through the electric windings 55 and the permanent magnets 53 as a function of the supply of said windings cause the linear displacement of said carriage 52.

Figures 8A, 8B and 8C show views similar to those of previous figures 7A, 7B and 7C. The device 60 comprises, as before, an elongated carcass, not shown, a fixed linear stator 61 and a carriage 62 movable alternately with respect to said fixed linear stator 61 and carrying said magnetic arrangement, in this case composed of a series of associated electromagnets 63 each has a magnetically permeable element 64. The fixed linear stator 61 comprises a set of electric windings 65 with axes parallel and perpendicular to the direction of movement of the carriage 62. A series of magnetocaloric elements 66 is aligned in the gap, along at least part of the fixed linear stator between said fixed linear stator 61 and said magnetic arrangement.

The three figures 8A, 8B and 8C correspond to three successive positions of the carriage 62 mobile linearly during its movement. The operating mode of the device 60 is identical to that of the previous device 50 of Figures 7A, 7B and 7C.

POSSIBILITIES OF INDUSTRIAL APPLICATION: The present invention is not limited to the embodiments described, but extends to any modification and variant obvious to a person skilled in the art while remaining within the scope of the protection defined in the appended claims. . The number of magnets that make up the magnetic arrangement, their shape and their arrangement can be modified according to the desired objectives in terms of efficiency, size, rotational speed of the rotor, etc. The number of electrical windings can also vary according to the objectives to be achieved. The nature of the materials, especially magnetocaloric materials, that of magnetically permeable elements and that of other components such as the carcass of the device can be modified as needed.

Claims (19)

Revendications1. Thermal flux generation device with magnetocaloric material (10, 20, 100, 50, 60) comprising at least one thermal flux generation unit provided with at least one heat element containing at least one magnetocaloric element, at least one magnetic arrangement arranged to generate a magnetic field, at least one electric drive arranged to move said magnetic arrangement with respect to said magnetocaloric element (13, 23, 56, 66) in order to subject it to a magnetic field variation and to cause a variation of its magnetic field temperature, means for sensing calories and / or frigories emitted by said magnetocaloric element due to said variation of the magnetic field, characterized in that said electric drive is integrated with the magnetothermal material heat flow generating device (10, 20, 100, 50, 60) and comprises at least two electrical windings (14, 24, 55, 65) characterized by electrical current so as to generate a magnetic field variation which causes displacement of a movable assembly carrying said magnetic arrangement and in that said thermal member containing said magnetocaloric element is disposed between said electric windings and said magnetic arrangement. 2. Device according to claim 1, wherein said electric drive is a rotary motor, characterized in that it comprises a peripheral carcass (11, 21), a stator (15, 25) housed in this carcass and a rotor (12). , 22) mounted inside said carcass coaxially with said stator, said rotor carrying said magnetic arrangement, and said magnetocaloric element (13, 23) is disposed in the gap between said rotor and said stator. 13 3. Device according to claim 1, wherein said electric drive is a linear motor, characterized in that it comprises an elongate carcass, a fixed linear stator (51, 61) and a movable carriage (52, 62) alternatively with respect to said stator and carrying said magnetic arrangement, and in that said magnetocaloric element (56, 66) is disposed in the air gap between said linear stator and said movable carriage. 4. Device according to claim 2, characterized in that said rotor carrying said magnetic arrangement comprises a set of permanent magnets (17). 5. Device according to claim 3, characterized in that said magnetic arrangement of said movable carriage (52) comprises a set of permanent magnets (53). 15 6. Device according to claim 4, characterized in that said permanent magnets (17) of said magnetic arrangement of said rotor comprise at least one magnetically permeable element (18). 7. Device according to claim 5, characterized in that said permanent magnets (53) of the magnetic arrangement of said movable carriage (52) comprise at least one magnetically permeable element (54). 8. Device according to claim 2, characterized in that it comprises at least one ring of magnetocaloric elements (13, 23) surrounding said rotor (12, 22) and disposed in the air gap between said stator and said rotor. 9. Device according to claim 3, characterized in that it comprises at least one row of magnetocaloric elements (56, 66) aligned along at least a portion of the fixed linear stator (51, 61), in the air gap between said linear stator and said movable carriage. 10. Device according to claim 2, characterized in that said stator (15, 25) comprises a set of electric windings (14, 24) each having an axis disposed in a substantially radial direction. 11. Device according to claim 3, characterized in that said fixed linear stator (51, 61) comprises a set of electric windings (55, 65) having axes parallel and substantially perpendicular to the direction of movement of said movable carriage (52). , 62). 12. Device according to claim 1, characterized in that each of said electrical windings comprises a winding carried by a frame (16) T-shaped and comprising a base piece (16a) and a branch (16b) perpendicular to the base piece (16a). 13. Device according to claim 12, characterized in that said armature (16) is made of one of the materials selected from the group consisting of soft iron, an alloy of iron and cobalt (FeCo), an alloy of iron and silicon (FeSi). 14. Device according to claim 1, characterized in that said magnetic arrangement comprises at least one magnetic flux concentrator. 25 15. Device according to claim 14, characterized in that said magnetic flux concentrator is made of one of the materials selected from the group consisting of soft iron, an alloy of iron and cobalt (FeCo), an alloy of iron and silicon (FeSi). 10 15 20 30 16. Device according to claim 14, characterized in that saidconcentrateur magnetic flux is made of stacked sheets. 17. Device according to claims 10, characterized in that said set of electric windings (14, 24) has a geometrical asymmetry with respect to the flux lines generated by said magnetic arrangement to impose a preferred direction of rotation to said rotor (12, 22). ). 18. Device according to claims 11, characterized in that said set of electric windings (55, 65) has a geometrical asymmetry with respect to the flux lines generated by said magnetic arrangement to impose a preferred direction of linear motion to said movable carriage (52). , 62). 19. Device according to claim 1, characterized in that it comprises means (30) for driving said electric windings, these means comprising at least one electronic circuit arranged to switch sequentially said electric windings.