HK1099801B - Heat generator comprising a magneto-caloric material and thermie generating method - Google Patents

Description

Thermal generator of magnetocaloric material and method for generating heat

Technical Field

[01] The invention relates to a heat generator of magnetocaloric material, having at least one thermal element, at least one magnetic element for generating a magnetic field, said thermal element being arranged facing said magnetic element so as to be able to withstand at least part of the magnetic field, said heat generator further having magnetic modulation means arranged to modify the magnetic field received by said thermal element, and recovery means to recover at least part of the heat generated by the thermal element subjected to the variable magnetic field.

[02] The invention also relates to a method for generating heat, during which at least one thermal element is subjected to at least one portion of a magnetic field generated by at least one magnetic element, the magnetic field received by said thermal element is modulated by magnetic modulation means, and at least one portion of the heat generated by said thermal element subjected to the variable magnetic field is recovered.

Background

[03] Known thermal generators of magnetocaloric material use the magnetocaloric properties of certain materials, such as gadolinium or certain alloys, which are characterized by heating under the action of a magnetic field and by cooling at a temperature lower than their initial temperature after the disappearance of said magnetic field or as the latter weakens. In fact, when passing before the magnetic field, the magnetic moments of the magnetocaloric material align, which causes an atomic rearrangement effect, causing the magnetocaloric material to heat up. Outside the magnetic field or in the case of weakening of the magnetic field, the process is reversed and the magnetocaloric material cools down until reaching a temperature less than its initial temperature.

[04] A prototype of a magnetocaloric material heat generator having a disc shaped member formed of thermal segments containing a gadolinium alloy magnetocaloric material has been developed by a team of researchers in the united states. The disc is guided for continuous rotation about its axis so that its hot section is advanced into and out of a magnetic field generated by a stationary permanent magnet straddling a portion of the disc. Facing the permanent magnets, the disc enters a heat transfer assembly having two heat transfer fluid circuits, one for the delivery of calories and the other for the delivery of negative calories, the calories and the negative calories being generated by hot zones alternately subjected and not to the magnetic field. The heat transfer assembly has holes that open onto the rotating disc and allow contact between the heat transfer fluid and the rotating hot section. Despite the provision of rotary joints, it is difficult to ensure tightness between the thermal section and the heat transfer assembly without compromising the overall efficiency of the heat generator. Furthermore, each time a hot section is subjected or not to the magnetic field, and thus generates heat or cooling, the respective inlet and outlet must be switched to the hot or cold circuit. Therefore, the device is complex in structure, less safe and reliable, limited in efficiency, and unsatisfactory.

[05] The heat generator proposed in WO-A-03/050456 is substantially similar to the previously described generator and uses two permanent magnets. The heat generator has an integral annular chamber defining twelve thermal compartments separated by joints, each thermal compartment receiving gadolinium in a porous form. Each hot compartment is provided with at least four apertures, wherein an inlet aperture and an outlet aperture are connected to a hot circuit and an inlet aperture and an outlet aperture are connected to a cold circuit. The two permanent magnets are subjected to a continuous rotary motion so that they pass through the different thermal compartments, subjecting them to a magnetic field one after the other. The calories and/or the negative calories emitted by the hot compartment are directed to the heat exchanger by a hot and cold circuit of the heat transfer fluid, the hot compartment is connected in succession to the hot and cold circuits by means of a plurality of rotary joints, the rotation of which is linked by means of one or more belts to a drive shaft that drives the two magnets in continuous rotation. The heat generator thus simulates the operation of a liquid loop.

[06] In order to work, the heat generator requires continuous, synchronous and precise rotation of the various rotary joints and permanent magnets. The requisite commutation and tightness associated with said rotation makes the heat generator technically difficult to implement and costly. Furthermore, the continuous working principle makes the technical development prospects of the heat generator very limited.

Disclosure of Invention

[07] The present invention aims to remedy these drawbacks by proposing a thermal generator of magnetocaloric material that is efficient, safe, reliable, simple in design, less expensive, energy-saving, has good efficiency, does not require synchronization means between the movements of the magnetocaloric elements, does not require means for switching alternately to the hot circuit and to the cold circuit, such as in the above mentioned american researchers' prototype, can greatly limit the inertial mass movements to implement the magnetic field variations necessary to obtain the magnetocaloric effect, and can be used in large industrial and domestic apparatuses.

[08] To this end, the invention relates to a heat generator of the type stated in the preamble, characterised in that the magnetic modulating means have at least one magnetic modulating element which is magnetically conductive and is connected to moving means arranged to be moved alternately with respect to the magnetic element and the thermal element between an operating position, in which the magnetic modulating element is close to the magnetic element and the thermal element and is arranged to direct at least the portion of the magnetic field intended to be received by the thermal element, and an inactive position, in which the magnetic modulating element is remote from the magnetic element and/or the thermal element and is arranged to have no effect on this portion of the magnetic field.

[09] The magnetic modulating element may be a magnetic concentrating element made of a material having a magnetic permeability greater than that present in the ambient medium separating the magnetic element and the thermal element, the magnetic concentrating element being arranged in the operative position to facilitate passage of the magnetic field in the direction of the thermal element, the effect of which is to intensify the magnetic field passing through it.

[10] The magnetic modulating element may also be a magnetic dispersion element made of a material having a magnetic permeability greater than that of the thermal element, the magnetic dispersion element having at least one shape adapted to surround the thermal element and being arranged to deflect at least a portion of the magnetic field away from the thermal element in the operative position, the effect of which is to attenuate the magnetic field passing through it.

[11] The magnetic modulating element is preferably made of at least one of the following materials: soft iron, ferrites (ferriites), iron alloys, chromium alloys, vanadium alloys, composites (composites), nano-composites, permalloy (permaHoys).

[12] According to a preferred embodiment, the heat generator has at least one magnetic converging element, also called "magnet iron (loupe)", and at least one magnetic diverging element, also called "heat spreader or shunt", arranged to alternately facilitate the passage of the magnetic field in the direction of the thermal element and to deviate the magnetic field from the thermal element.

[13] In the operating position, the magnetic modulating element is preferably interposed between the magnetic element and the thermal element.

[14] The magnetic element preferably has at least one positive magnetic terminal and at least one negative magnetic terminal, the thermal element being arranged between the positive magnetic terminal and the negative magnetic terminal, and the magnetic modulation element being interposed at least between the positive magnetic terminal and the negative magnetic terminal at least in the operating position.

[15] Preferably:

[16] the magnetic convergence element may have two convergence plates arranged between the thermal element and the positive and negative magnetic terminals on either side of the thermal element in the operating position, and/or

[17] The magnetic radiating element may be U-shaped or C-shaped for straddling the thermal element between the thermal element and the positive and negative magnetic terminals, at least in the working position.

[18] According to another advantageous embodiment, the magnetically divergent element mj has at least one thrust block for being arranged in the operating position tangentially to the thermal element Ti and tangentially to the magnetic terminals, the magnetic pole gap separating the thermal element Ti and the magnetic terminals 40, 41 remaining clear. The pole gap may be 0mm to 50mm, preferably less than 1 mm.

[19] The magnetic element may be U-shaped or C-shaped, the shape being for straddling the magnetic modulating element.

[20] The moving part may be arranged to drive the magnetic modulating element in at least one of the following movements: continuous rotation, stepwise rotation, alternating pivoting, continuous translation, stepwise translation, alternating translation, combinations of these movements.

[21] The moving part is preferably connected to an operating part selected from the group consisting of: an electric motor, a power cylinder, a spring mechanism, a pneumatic generator, an electromagnet, a hydraulic generator and a muscle force type mechanism.

[22] The magnetic modulation element is preferably supported by a support which is connected to the moving part and is made of a magnetically insulating material, which comprises in particular synthetic materials, brass, bronze, aluminum, ceramics.

[23] The heat generator preferably has at least one set of magnetic elements, a set of thermal elements, each for being subjected to the magnetic field of at least one of the magnetic elements, a set of magnetic modulation elements, supported by a support, connected to the moving part and arranged to simultaneously move the magnetic modulation elements each alternately into the active and inactive positions with respect to a certain thermal element and with respect to a certain magnetic element.

[24] According to a first embodiment, the support has at least one substantially circular platform rotating about its central axis, the thermal elements are arranged in a ring and the magnetic elements form at least one pair of annular elements defining the positive and negative magnetic terminals.

[25] In this configuration, the platform is preferably provided with a slot defining a gap separating the converging sheets of the magnetic converging elements from each other and/or a U-shaped or C-shaped opening of the magnetic diverging elements. The slot portion may be axially disposed and substantially parallel to the central axis of the platform or radially disposed and substantially perpendicular to the central axis of the platform.

[26] According to a second embodiment, the support has at least one substantially straight, translationally movable rod, the thermal elements are arranged in at least one row of thermal elements supported by a cross-beam, and the magnetic elements form at least two rows of magnetic elements defining the positive and negative magnetic terminals.

[27] In this configuration, the thermal elements may be arranged in two substantially parallel rows, supported by cross beams, which are connected to define a frame.

[28] Preferably, the magnetic element may form a single component.

[29] The magnetic element is preferably selected from a magnetic assembly, a permanent magnet, an electromagnet.

[30] According to a particular embodiment, the magnetic elements and the thermal elements are fixed, only the magnetic modulating elements being movable.

[31] Preferably, the recovery part has at least one of the following components: a conveying loop containing heat-carrying fluid, a circulating component of said heat-carrying fluid and a heat exchanger.

[32] The invention also relates to a method of generating heat of the type described in the preamble, characterised in that for varying the magnetic field received by the thermal element, at least one magnetically conductive magnetic modulation element is used, which is moved between at least an operating position, in which it is close to the magnetic element and the thermal element and is arranged to guide at least part of the magnetic field for reception by the thermal element, and an inoperative position, in which it is remote from the magnetic element and/or the thermal element and is arranged to have no effect on this part of the magnetic field.

[33] Preferably, at least one magnetic element is used to define at least a positive terminal and a negative terminal, the thermal element being disposed between the positive and negative terminals, and the magnetic modulating element being interposed between at least the magnetic terminals of the magnetic element in the operative position.

Drawings

[34] The invention and its advantages will be better understood in the following description of several embodiments, given as non-limiting examples, with reference to the accompanying drawings, in which:

[35] FIG. 1 is a perspective view of a partially assembled heat generator according to a first embodiment of the present invention;

[36] 2A-2C are perspective views substantially similar to the previous figures, showing the heat generator in different stages of assembly;

[37] FIG. 3A is a top view of the heat generator of FIG. 2A, and FIGS. 3B and 3C are cross-sectional views taken along section AA in FIG. 3A;

[38] FIGS. 4A and 4B are bottom and perspective views, respectively, of the magnetic modulating element of FIG. 3A, and FIG. 4C is a cross-sectional view taken along section BB in FIG. 4A;

[39] fig. 5A is a view similar to fig. 3A showing a heat generator according to the present invention according to a second embodiment, and fig. 5B and 5C are sectional views taken along section CC in fig. 5A;

[40] FIGS. 6A and 6B are bottom and perspective views, respectively, of the magnetic modulating element of FIG. 5A, and FIG. 6C is a cross-sectional view taken along section DD in FIG. 6A;

[41] FIGS. 7A-7D are perspective, top plan and cross-sectional views, respectively, of a heat generator of the present invention according to another embodiment, and FIG. 7D is a perspective view of the magnetic modulating element of FIG. 7C;

[42] FIGS. 8A and 8B are a cross-sectional view and a perspective view, respectively, of another embodiment of the magnetic modulating element;

[43] FIGS. 9A and 9B are top and perspective views, respectively, of a third embodiment of the heat generator of the present invention; and

[44] FIGS. 9C and 9D are cross-sectional views of the device shown in the drawings taken along the respective sections EE and FF in FIG. 9A; and

[45] fig. 10 is a cross-sectional view of a fourth embodiment of the heat generator of the present invention.

Detailed Description

[46] In a known manner, a heat generator of magnetocaloric material has a thermal element Ti subjected to a magnetic field generated by magnetic elements Gi. The thermal element Ti contains magnetocaloric materials, such as: gadolinium (Gd), gadolinium alloys containing, for example, silicon (Si), germanium (Ge), iron (Fe), magnesium (Mg), phosphorus (P), arsenic (As) or any other material, or equivalent magnetocaloric alloys. Generally, the magnetocaloric materials may be in the form of blocks, flakes, powders, clusters, or any other suitable shape, and may be based on only one material or a combination of magnetocaloric materials.

[47] The magnetic element Gi may have one or more solid, sintered or laminated permanent magnets, which are connected to one or more magnetizable materials, which gather and guide the magnetic field lines of the permanent magnets. The magnetizable material may contain iron (Fe), cobalt (Co), vanadium (V), soft iron, combinations of these materials, or any equivalent material. Obviously, any other type of equivalent magnet may be used, such as a magnetic element, an electromagnet, a superconducting magnet, a superconducting electromagnet, a superconductor.

[48] For the sake of simplicity, hereinafter "generator" refers to a heat generator of the magnetocaloric material type according to the invention.

[49] Before explaining the constructional details of the different embodiments of the generator of the invention, its general working principle will be explained below with reference to the device shown in the accompanying drawings.

[50] The generators 10-14 have magnetic modulating elements Mj, Mj made of magnetically permeable material, such as soft iron, ferrite, iron alloy, chromium alloy, vanadium alloy, hybrid, ultramicroelement, permalloy or any other material with similar characteristics. Each magnetic modulating element Mj, Mj is connected to moving means (not shown) so as to be alternately movable between an operating position and a non-operating position with respect to said thermal element Ti and with respect to said magnetic element Gi, so as to create variations in the magnetic field received by said thermal element Ti.

[51] In the operating position, each magnetic modulation element Mj, Mj is close to a magnetic element Gi and a thermal element Ti, so as to pass the magnetic field emitted by said magnetic element Gi, passing through said magnetic modulation element Mj, Mj in the direction of said thermal element Ti, intensifying the magnetic field admitted by said thermal element Ti.

[52] In the inactive position, the magnetic modulation elements Mj, Mj are distanced from the magnetic elements Gi and/or the thermal elements Ti, so as to no longer have a significant influence on the magnetic field emitted by the magnetic elements Gi, weakening or modifying the magnetic field admitted by the thermal elements Ti.

[53] Obviously, the operative position of the magnetic modulation elements Mj, Mj with respect to a pair of magnetic elements Gi and thermal element Ti corresponds to the inoperative position of the same magnetic modulation elements Mj, Mj with respect to a pair of magnetic elements Gi +1 and thermal element Ti +1, for example adjacent to the magnetic elements Gi and thermal element Ti.

[54] The magnetic modulating element may be a magnetic converging element Mj made of a material having a magnetic permeability greater than the magnetic permeability existing between the magnetic element Gi and the thermal element Ti, for example greater than the magnetic permeability of air. In the operating position, the magnetic convergence elements Mj facilitate the passage of the magnetic field, first through the magnetic convergence elements Mj and then through the thermal elements Ti arranged facing each other. Thus, when said magnetic converging element Mj is close to a pair of magnetic elements Gi and thermal element Ti in the operating position, said thermal element Ti is subjected to a magnetic field stronger than the magnetic field to which said magnetic converging element Mj is subjected when it is far from said pair of magnetic elements Gi and thermal element Ti in the non-operating position.

[55] The magnetic modulating elements can also be magnetically diverging elements mj made of a material having a magnetic permeability greater than that of the thermal element Ti, the magnetically diverging elements mj each having a shape adapted to surround the thermal element Ti. In the operating position, these magnetically divergent elements mj contribute to the passage of the magnetic field through them, which surrounds the hot element Ti arranged facing it. Thus, when the magnetic dispersion element mj is close to a pair of magnetic elements Gi and thermal element Ti in the operating position, the thermal element Ti is subjected to a magnetic field that is zero or at least weaker than the magnetic field to which the magnetic dispersion element mj is subjected when it is far from the pair of magnetic elements Gi and thermal element Ti in the non-operating position.

[56] As will be described in detail below, it is clear that for each pair of magnetic elements Gi and thermal elements Ti, a magnetic diverging element Mj and a magnetic converging element Mj can be used alternately, exploiting the efficiency of both magnetic modulating elements Mj, Mj.

[57] As shown in fig. 1 to 6, and according to a first embodiment, the generator 10-11 has a set of twelve thermal elements Ti arranged in a circle with a centre a on an annular interface plate 20 to form a thermal ring. Each thermal element Ti has a block 30 of magnetocaloric material and is crossed by two channels (not shown) which are provided with hot and cold inlet holes and with hot and cold outlet holes. These ducts are intended to receive the heat transfer fluid to be heated and the heat transfer fluid to be cooled, respectively.

[58] The interface plate 20 is made of a mechanically rigid, thermally insulating material, for example a composite material, a composite material or any other equivalent material. The tightness is ensured by a sealing plate 22, said sealing plate 22 being made of a mechanically rigid insulating material, for example of a composite material, a synthetic material or any other equivalent material. The seal plate 22 has at least four holes: a cold circuit inlet aperture, a cold circuit outlet aperture, a hot circuit inlet aperture, and a hot circuit outlet aperture. These holes 21 are intended to be connected to an external hot circuit and to an external cold circuit (not shown) by conventional connecting and distributing means (not shown). The hot element Ti is fixed and the connection of the external cold and hot circuits to the inlet and outlet holes 21 is made with or without simple quick hydraulic connections.

[59] The external hot and cold circuits are formed, for example, by rigid, semi-rigid or flexible conduits in which the heat-carrying fluid circulates, and are each connected to one or more heat exchangers (not shown) or any other equivalent member capable of recovering calories and negative calories. As described below, this heat exchanger 10-11 can thus recover both the calories given off by the heating element Ti of the thermal ring and the negative calories.

[60] The circulation of the heat transfer fluid is ensured, for example, by strong or free-flow means (not shown), such as a pump or any other equivalent. The heat transfer fluid used is selected in particular according to the desired temperature range. For example, clean water is used at positive temperatures and anti-freeze make-up water is used at negative temperatures. For very low temperatures, a gas such as helium may be used as the heat-carrying fluid.

[61] The inlet and outlet holes 21 of each hot and cold circuit are connected to each other by hot and cold ducts (not shown) located inside said interface plate 20 and associated with the inlet and outlet holes, respectively, of the heating element Ti, relatively unblocked. The heat conducting duct thus connects the inlet and outlet apertures of the thermal circuit to the hot inlet and outlet apertures. Also, the cold guide channel connects the inlet and outlet ports of the cold circuit to the cold inlet and outlet ports. These channels can be used to connect the thermal elements Ti in parallel or in series. The guide channel can be made, for example, by machining or molding.

[62] The generator 10-11 has twelve magnetic elements Gi, each of which is U-shaped or C-shaped, defining a positive magnetic terminal 40 and a negative magnetic terminal 41. These magnetic elements Gi are arranged concentrically and circularly at a distance from the centre a to straddle the thermal elements Ti of the thermal ring. It is obvious that the magnetic element Gi may have any other suitable shape.

[63] As shown in fig. 1 to 4C, the U-shaped or C-shaped opening of the magnetic elements Gi is axially oriented substantially parallel to the axis of the circle passing through the centre a and defined by the magnetic elements Gi, so as to define, with respect to the thermal ring, an outer magnetic ring, for example a negative magnetic ring, and an inner magnetic ring, for example a positive magnetic ring — or vice versa, or a combination of pairs of positive and negative terminals in no particular order. Thus, each thermal element Ti is disposed between a positive magnetic terminal 40 and a negative magnetic terminal 41.

[64] The magnetic modulating component has six magnetic converging elements Mj and six magnetic diverging elements Mj arranged in a circle having a centre a, arranged alternately and supported by a support 52 a. The magnetic convergence element Mj has two convergence plates 50, the convergence plates 50 being arranged opposite each other and separated by a gap sufficient to receive a thermal element Ti without contact between these thermal elements Ti and the magnetic terminals 40, 41 surrounding them. The magnetic radiating elements mj each define a U-or C-shape 51, straddling some of the thermal elements Ti and the magnetic terminals 40, 41 surrounding them.

[65] In this embodiment, the magnetic converging elements Mj and the magnetic diverging elements Mj are arranged alternately on the support 52 a. Thus, in a certain position, the magnetic converging element Mj is in the direct environment of one of the two thermal elements Ti, Ti +2, while the magnetic diverging element Mj is in the direct environment of one of the two thermal elements Ti +1, Ti + 3. The support has a substantially circular platform 52a coaxial with the magnetic and thermal rings. The converging blades 50 and the diverging U-or C-shaped profile 51 are arranged on the platform 52, for which purpose the platform 52 has a housing 53a (see fig. 4B, 4C) receiving them and a recess 54A (see fig. 4A, 4B), the recess 54A defining a gap in which the thermal element Ti is free to move without contact. The platform 52a is made of a magnetically insulating material such as synthetic material, brass, bronze, aluminum, ceramic, or the like. The platform 52a is connected to a moving part (not shown) for rotation about its axis passing through the centre a.

[66] The moving part is for example connected to an operating part such as an electric motor, a power cylinder, a spring mechanism, a pneumatic generator, an electromagnet, a hydraulic force generator or any other suitable actuator. The manipulating member drives the platform 52a to move, such as to rotate continuously, to rotate stepwise, to pivot alternately, or to any combination of these movements.

[67] The operation of the generator 10 can be divided into two phases, carried out in succession, stepwise or alternately, according to the moving parts used. As an example, the two stages are described in order below. Obviously, the passage from one stage to another may be gradual. It is optionally contemplated that the magnetic element Gi permanently emits its magnetic field.

[68] In a first phase and simultaneously:

[69]1) a magnetic convergence element Mj arranged between each thermal element Ti, Ti +2 and the corresponding magnetic element Gi, concentrating the magnetic field lines generated by these magnetic elements Gi, so that said magnetic field lines pass through said magnetic convergence element Mj and said thermal element Ti, Ti + 2. Thus, the magnetic concentration elements Mj are in the operating position with respect to the thermal elements Ti, Ti +2, the thermal elements Ti, Ti +2 receiving a greater amount of magnetic field than they would have received without the magnetic concentration elements Mj. Furthermore, these same magnetic concentration elements Mj are in a non-operating position with respect to the adjacent thermal elements Ti +1 and Ti +3, for which thermal elements Ti +1 and Ti +3 they have no influence with respect to the magnetic field to which they are subjected. The thermal elements Ti, Ti +2 subjected to magnetic field enhancement become hot. They transfer their calories towards the calorie exchanger to the hot carrier fluid of the hot circuit.

[70]2) a magnetic dispersion element mj arranged between each thermal element Ti +1, Ti +3 and the corresponding magnetic element Gi, which disperses and varies the magnetic field lines generated by these magnetic elements Gi along their U-or C-shape, said magnetic elements Gi surrounding said thermal elements Ti +1, Ti + 3. The magnetic dissipation elements mj are therefore in the operating position with respect to the thermal elements Ti +1 and Ti +3, the thermal elements Ti +1 and Ti +3 receiving a quantity of magnetic field that is practically absent and, in any case, significantly weaker than the magnetic field received by the thermal elements Ti +1 and Ti +3 in the absence of the magnetic dissipation elements mj. Furthermore, these same magnetically divergent elements mj are in a non-operating position with respect to the adjacent hot elements Ti, Ti +2, for which the hot elements Ti, Ti +2 have no influence with respect to the magnetic field they are subjected to. The thermal elements Ti, Ti +2 subjected to the field weakening cool and transfer their negative large cards towards the heat exchanger to the cold heat carrying fluid of the cold circuit.

[71] Thus, at the same time:

[72] -magnetic convergence towards said thermal elements Ti, Ti +2, said thermal elements Ti, Ti +2 being heated by said magnetic convergence elements Mj, and

[73] -the heating elements Ti +1, Ti +3 cool with respect to the magnetic divergence of the heating elements Ti +1, Ti + 3.

[74] To enter the second phase from the first phase, the moving means drives the stage 52a to move by a lead corresponding to the center distance separating two adjacent heat elements Ti, Ti +1, so as to:

[75] -having said magnetic converging elements Mj between said thermal elements Ti +1, Ti +3 and the respective magnetic elements Gi, and

[76] -bringing said magnetic dispersion element mj between said thermal elements Ti, Ti +2 and the respective magnetic elements Gi.

[77] The thermal elements Ti +1, Ti +3 subjected to the magnetic field enhancement heat up and transfer their calories, and the thermal elements Ti, Ti +2 subjected to the magnetic field reduction cool down and transfer their negative calories.

[78] Then, by rotation of the platform 52a, a new phase is entered from the second phase, and so on, so that each thermal element Ti, Ti +1, Ti +2, Ti +3 is alternately subjected to a magnetic field enhancement and a magnetic field attenuation, causing a magnetic field variation that favours the production of negative big cards and/or calories.

[79] As shown in fig. 5 and 6, the generator 11 differs from the aforementioned generators in that the magnetic modulating means have six magnetic converging elements Mj, but do not have magnetic diverging elements. The magnetic convergence elements Mj are arranged substantially the same as in the previous embodiment, the lands 52b being solid between the magnetic convergence elements Mj.

[80] The operation of this generator 11 is substantially similar to that of the generator 10 described above. One of the two thermal elements Ti, Ti +2 is subjected to a magnetic field enhancement by a magnetic convergence element Mj. The other thermal elements (not shown) are subjected to a weakening by a magnetic field that is diffuse and constrained by the U-shape of the platform 52B, the arms 55 (see fig. 6A, 6B, 6C) of the platform 52B, made of magnetically insulating material or neutral material, being between the magnetic elements Gi and the thermal elements Ti.

[81] As shown in fig. 7 and 8, the generator 12 is substantially identical to the previously described generators. They differ in particular in that they have eight magnetic elements Gi and eight thermal elements Ti. Furthermore, the U-shaped or C-shaped opening of the magnetic element Gi is oriented radially substantially perpendicular to an axis passing through the centre a and defines two magnetic rings of substantially equal diameter having a centre a. Likewise, the grooves 54e-d of the plates 52c-d are radially disposed. The operation of these generators 12 is substantially similar to that of the aforementioned generators.

[82] In the embodiment shown in fig. 7A-7D, the magnetic modulating component has four magnetic converging elements Mj and four magnetic diverging elements Mj, which are arranged alternately and supported by the platform 52 c.

[83] In the embodiment shown in fig. 8A and 8B, the magnetic modulating component has four magnetic converging elements Mj, but no magnetic diverging elements. Said magnetic convergence elements Mj have a U-or C-shape, the arms of which define convergence tabs 51, said convergence tabs 51 being arranged substantially as in the previous embodiment, said platform 52d being solid between these magnetic convergence elements Mj for insertion into the magnetic field.

[84] Fig. 9A-9D illustrate another embodiment of the generator 14 of the present invention. The generator 14 has ten thermal elements Ti arranged in two rows, supported by cross beams 70, said cross beams 70 being connected to form a frame 72. The frame 72 has inlet and outlet openings 71 of the cold and hot circuits, said inlet and outlet openings 71 being connected by a not shown duct as described before.

[85] The generator 14 has three magnetic modulating elements Mj supported by a support having a substantially straight bar 52e disposed between the rows of thermal elements Ti. The rod 52e is made of a mechanically rigid, thermally insulating material, such as a composite material, or any other equivalent material. The magnetic modulating elements Mj are arranged on both sides on the rod 52e so as to straddle one pair of the thermal elements Ti, Ti +2 or Ti +1, Ti +3 of the two pairs.

[86] In this embodiment, the magnetic modulating element is a magnetic converging element Mj. It is clear that a substantially similar generator can be provided, also with magnetically divergent elements.

[87] The rod 52e is connected to a moving member so as to be movable in translation, so as to move the magnetic convergence element Mj with respect to the thermal element Ti. This translation may be continuous, stepwise, alternating. The generator 14 has ten magnetic elements Gi in U, C or similar shape, arranged in columns, each defining a positive 40 and a negative 41 magnetic terminal (see fig. 9C and 9D), straddling the thermal element Ti or not straddling the magnetic convergence element Mj.

[88] The operation of this generator 14 is substantially similar to that of the generator 11 shown in figures 6 and 8. The difference is that between the two magnetic converging elements Mj the magnetic field is not stopped or limited by the rod 52e, for example the platforms 52b, 52d, but only by air and/or the ambient medium between the magnetic element Gi and the thermal element Ti. The magnetic field variation is thus obtained by the magnetic conduction difference between the air and/or said ambient medium and the magnetically conductive material of said magnetic concentrator element Mj.

[89] In the described embodiment, the magnetic element Gi and the thermal element Ti are fixed. Obviously, some and/or others may be configured to be active if required for general operation of a device.

[90] According to another embodiment, not shown, the magnetic element may be formed from a single component. In the case of a circular generator, the single member may be solid inner and outer rings and/or an inner hub.

[91] According to another embodiment, shown in fig. 10, the magnetic modulating element is arranged tangentially to the magnetic element and the thermal element, without being arranged therebetween. In this embodiment, the generator 13 has magnetically divergent elements mj supported by a rotationally movable platform 52f having an axis a and alternating with the solid areas of the platform 52 f. Each magnetically divergent element mj has at least one thrust block 500, said thrust block 500 having a shape complementary to the shape of said thermal element Ti and of said magnetic terminals 40, 41, so as to be able to be between said magnetic terminals 40, 41 and not between said magnetic terminals 40, 41 and said thermal element Ti in the operating position. In the operating position, the thermal element Ti is arranged tangentially to the thermal element Ti and to the magnetic terminals 40, 41. The thermal element is separated from the magnetic terminations 40, 41 by a pole gap E of 0mm to 50mm, preferably less than 1 mm. The pole gap E remains open in the active position and in the inactive position and allows the magnetic field to enter between the magnetic terminals 40, 41 and the thermal element Ti.

[92] The operation of this generator 13 is substantially similar to that of the generator 11 described previously, with the difference that the magnetic diverging elements mj are involved here, and not the magnetic convergence. In the inactive position, the magnetic radiating element mj is distanced from the thermal element Ti and from the magnetic terminals 40, 41. Thus, the magnetic field is free to pass through the thermal element Ti, which generates heat. In the operating position, the magnetic radiating element mj is tangent to the thermal element Ti and to the magnetic terminals 40, 41. Since the magnetic dispersion element mj is more magnetically permeable than air or the surrounding medium of the pole gap E, the magnetic field deviates and avoids the thermal element Ti, which cools.

[93] The heat generators 10-14 can be connected to other similar or dissimilar generators, in series and/or in parallel and/or in series/parallel combinations, to enhance the thermal power of a plant, without complicating the operation and without complicating the structure, the movement of the magnetic modulating element being easily implemented. Each generator 10-14 may have a different number of thermal, magnetic and/or magnetic modulating elements than the generators described, without limitation.

[94] Thus, the generators 10-14 may simply generate negative calories and/or calories because only the magnetic modulating element must be moved. These negative calories and calories can be used for heating, cooling, air conditioning of rooms, appliances, sites, for industrial applications and for household use. The particular structure of the generators 10-14 does not present any tightness problems in the thermal circuit and greatly limits the inertial mass movement so that the magnetic field generates the magnetic field variations necessary to obtain the magnetocaloric effect.

[95] In the described embodiment, the ambient medium is air. It will be apparent that the generators 10-14 may be used in any other type of suitable environmental medium. It is also possible to use generators 10-14 with a dedicated internal ambient medium, for example a gas, which generators 10-14 are arranged in a different external ambient medium, for example another gas or any other fluid ambient medium. In this case, the two ambient media can be separated from one another, for example, by a housing.

[96] The description shows that the generator 10-14 of the present invention achieves the intended purposes, since it is effective, simple in design, simple in operation, simple in follower means and therefore less expensive to implement and use than conventional generators. Furthermore, the generator of the invention greatly limits the inertial mass movement to make the magnetic field undergo the changes necessary to obtain the magnetocaloric effect.

[97] The invention is not limited to the described embodiments but comprises any modifications and other embodiments obvious to a person skilled in the art within the scope of protection defined by the appended claims.

Claims (29)

1. -a heat generator (10-14) of magnetocaloric material having at least one thermal element (Ti), at least one magnetic element (Gi) for generating a magnetic field, said thermal element (Ti) being arranged facing said magnetic element (Gi) so as to be able to withstand at least a portion of said magnetic field, said heat generator (10-14) further having: a magnetic modulating component arranged to modify the magnetic field received by the thermal element (Ti); and a recovery means that recovers at least a portion of the heat generated by the thermal element (Ti) subjected to the variable magnetic field,

characterized in that said magnetic modulating means have at least one magnetically conductive magnetic modulating element (Mj, Mj) connected to moving means arranged to move said magnetic modulating element (Mj, Mj) alternately with respect to said magnetic element (Gi) and said thermal element (Ti) between an operating position, in which said magnetic modulating element (Mj, Mj) is close to said magnetic element (Gi) and said thermal element (Ti) and arranged to guide at least said portion of said magnetic field to be received by said thermal element (Ti), and an inoperative position, in which said magnetic modulating element (Mj, Mj) is far from said magnetic element (Gi) and/or said thermal element (Ti) and arranged to be inactive to this portion of the magnetic field.

2. Heat generator (10, 11, 12, 14) according to claim 1, characterized in that said magnetic modulating element is a magnetic converging element (Mj) made of a material having a magnetic permeability greater than the magnetic permeability present in the ambient medium separating said magnetic element (Gi) and said thermal element (Ti); and said magnetic convergence element (Mj) is arranged to facilitate, in the operating position, the passage of said magnetic field in the direction of said thermal element (Ti), the effect of which is to intensify the magnetic field passing through it.

3. Heat generator (10, 12, 13) according to claim 1, characterized in that said magnetic modulating element is a magnetic diffusing element (mj) made of a material having a magnetic permeability greater than that of said thermal element (Ti); the magnetically divergent element (mj) has at least one shape suitable for surrounding the thermal element (Ti) and is arranged to deviate, in the operating position, at least a portion of the magnetic field from the thermal element (Ti) with the effect of attenuating the magnetic field passing through it.

4. Heat generator (10-14) according to claim 1, characterized in that the magnetic modulation elements (Mj, Mj) are made of one of the materials from the group: soft iron, ferrites, iron alloys, chromium alloys, vanadium alloys, permalloy.

5. Heat generator (10, 12) according to claim 1, characterized in that it has at least one magnetic converging element (Mj) and at least one magnetic diverging element (Mj) arranged to alternately facilitate the passage of a magnetic field in the direction of the thermal element (Ti) and to deviate the magnetic field from the thermal element (Ti).

6. Heat generator (10, 11, 12, 14) according to claim 1, characterized in that in the operating position the magnetic modulating element (Mj, Mj) is interposed between the magnetic element (Gi) and the thermal element (Ti).

7. The heat generator (10-14) according to claim 6, characterized in that said magnetic element (Gi) has a positive magnetic terminal (40) and a negative magnetic terminal (41); the thermal element (Ti) is arranged between the positive magnetic terminal (40) and the negative magnetic terminal (41); and in the operating position, the magnetic modulation element (Mj, Mj) is interposed between the positive magnetic terminal (40) and the negative magnetic terminal (41).

8. Heat generator (10, 11, 12, 14) according to claim 7, characterized in that said magnetic modulating element (Mj) has two convergence slices (50), said convergence slices (50) being arranged between said thermal element (Ti) and said positive and negative magnetic terminals on both sides of said thermal element (Ti) in the operating position.

9. Heat generator (10, 12, 14) according to claim 7, characterized in that said magnetic modulating element (mj) has a U-or C-shaped shape (51) for straddling said thermal element (Ti) between said thermal element (Ti) and said positive and negative magnetic terminals, at least in the working position.

10. The heat generator (13) according to claim 7, characterized in that the magnetic modulating element (mj) has at least one thrust block (500), the thrust block (500) being intended to be arranged tangentially to the thermal element (Ti) and to the positive and negative magnetic terminals in the operating position, the magnetic pole gap (E) separating the thermal element (Ti) from the positive and negative magnetic terminals remaining clear.

11. A heat generator (13) according to claim 10, characterized in that the pole gap (E) is 0 to 50 mm.

12. Heat generator (13) according to claim 11, characterized in that the pole gap (E) is smaller than 1 mm.

13. Heat generator (10-14) according to claim 1, characterized in that the magnetic element (Gi) has a U-or C-shape for straddling the magnetic modulating element (Mj, Mj).

14. Heat generator (10-14) according to claim 1, characterized in that the moving means are arranged to drive the magnetic modulating element (Mj, Mj) according to at least one of the movements in the following group: continuous rotation, stepwise rotation, alternating pivoting, continuous translation, stepwise translation, alternating translation, combinations of these movements.

15. Heat generator (10-14) according to claim 2, characterized in that said moving means are connected to an operating member selected from the group: an electric motor, a power cylinder, a spring mechanism and an electromagnet.

16. The heat generator (10-14) according to any of claims 1 to 5, characterized in that the magnetic modulation element (Mj, Mj) is supported by a support (52a-f), said support (52a-f) being connected to the moving part and being made of a magnetically insulating material.

17. Heat generator (10-14) according to claim 15, characterized in that it has at least one set of magnetic elements (Gi), one set of thermal elements (Ti), each for being subjected to the magnetic field of at least one of said magnetic elements (Gi), one set of magnetic modulation elements (Mj, Mj), supported by a support (52a-f), said support (52a-f) being connected to said moving part and being arranged to move said magnetic modulation elements (Mj, Mj) simultaneously, for which each magnetic modulation element (Mj, Mj) is alternately in the active position and in the inactive position with respect to a given thermal element (Ti) and a given magnetic element (Gi).

18. A heat generator (10-13) according to claim 17, wherein said support has at least one substantially circular movable platform (52a-d, 52f) rotating about its central axis; the thermal elements (Ti) are arranged in a ring; and the magnetic element (Gi) forms at least one pair of annular members defining the positive magnetic terminal (40) and the negative magnetic terminal (41).

19. Heat generator (10-12) according to claim 18, characterized in that the platform (52a-d) is provided with a slot (54a-d), said slot (54a-d) forming a gap separating the converging sheets (50) of the magnetic converging elements (Mj) from each other and/or an opening of the magnetic diverging elements (Mj) in the shape of the U or C (51).

20. The heat generator (10, 11) according to claim 19 wherein said trough portion (54a, 54b) is axially disposed substantially parallel to a central axis of said platform (52a, 52 b).

21. The heat generator (12) according to claim 19 wherein the slots (54c, 54d) are radially disposed substantially perpendicular to a central axis of the platform (52c, 52 d).

22. The heat generator (14) according to claim 17, wherein the support has at least one substantially straight, translationally movable rod (52 e); said thermal elements (Ti) being arranged in at least one row, supported by a cross-member (70); the magnetic elements (Gi) form at least one pair defined as an array of rows of the positive magnetic terminals (40) and negative magnetic terminals (41).

23. Heat generator (14) according to claim 22, characterized in that said thermal elements (Ti) are arranged in two substantially parallel rows, supported by two cross-beams (70), said cross-beams (70) being mutually connected and forming a frame (72).

24. A heat generator according to claim 17, wherein the magnetic element is formed from a single piece.

25. Heat generator (10-14) according to claim 1, characterized in that the magnetic elements are selected in the group: a magnetic component, a permanent magnet and an electromagnet.

26. Heat generator (10-14) according to claim 1, characterized in that the magnetic elements (Gi) and the thermal elements (Ti) are fixed, whereas only the magnetic modulating elements (Mj, Mj) are movable.

27. Heat generator (10-14) according to claim 1, characterized in that the recovery means have at least one of the members in the group: a conveying circuit containing a heat-carrying fluid, circulating means of the heat-carrying fluid, and a heat exchanger.

28. Method for generating heat, in which at least one magnetic element (Gi) is used to generate a magnetic field, at least one thermal element (Ti) made of magnetocaloric material is subjected to at least one portion of said magnetic field, the magnetic field received by said thermal element (Ti) is modulated by magnetic modulation means, and at least one portion of the heat generated by said thermal element (Ti) subjected to the variable magnetic field is recovered,

characterized in that, in order to modify the magnetic field received by the thermal element (Ti), at least one magnetically conductive magnetic modulating element (Mj, Mj) is used, which is moved between at least an operating position, in which it is close to the magnetic element (Gi) and the thermal element (Ti) and is arranged to direct at least the portion of the magnetic field for reception by the thermal element (Ti), and an inactive position, in which it is remote from the magnetic element (Gi) and/or the thermal element (Ti) and is arranged not to direct this portion of the magnetic field.

29. Method according to claim 28, characterized in that at least one magnetic element (Gi) is used to define at least one positive terminal (40) and one negative terminal (41), the thermal element (Ti) being provided between the positive terminal (40) and the negative terminal (41); in the operating position, the magnetic modulation element (Mj, Mj) is interposed between at least the magnetic terminals (40, 41) of the magnetic element (Gi).