High-efficiency magnetocaloric generator
The magnetocaloric generator with superimposed magnetic rotors and optimized heat transfer system addresses efficiency and size constraints, enabling efficient and compact energy conversion for diverse applications.
Patent Information
- Authority / Receiving Office
- FR · FR
- Patent Type
- Patents
- Current Assignee / Owner
- Filing Date
- 2021-12-15
- Publication Date
- 2026-03-27
AI Technical Summary
Existing magnetocaloric generators face limitations in energy efficiency, heating capacity, and size constraints, making them unsuitable for commercial applications with space constraints and requiring improvements in performance, energy consumption, and customization for various applications.
A magnetocaloric generator design featuring two superimposed magnetic rotors with a stator in the air gap, a mechanical and magnetic coupling system, and a modular construction with a heat transfer circuit for axial fluid circulation, optimized by magnetic field uniformization and efficient rotational guidance, allowing for reversible energy conversion.
Enhances energy efficiency, reduces energy consumption, and achieves compact size suitable for commercial integration by optimizing thermodynamic cycles and reducing frictional losses, thus improving performance and adaptability across heating, cooling, and energy conversion applications.
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Abstract
Description
Title of the invention: Increased efficiency magnetocaloric generator. Technical field
[0001] The present invention relates to a magnetocaloric generator with increased efficiency comprising at least one set of active elements based on magnetocaloric material, and a magnetic arrangement designed to be mobile relative to the set of active elements. Previous technique
[0002] The technology of ambient temperature magnetic refrigeration has been known for over forty years, and its advantages in terms of energy efficiency and reduced environmental impact compared to conventional technologies based on the compression and expansion of a refrigerant gas are well known. Its limitations regarding its heating capacity or energy conversion are also known. Therefore, research in this field is all aimed at improving the performance of magnetocaloric generators by manipulating various parameters, such as the intensity and quality of the magnetic field, the performance of the magnetocaloric material, the heat exchange surface area between the heat transfer fluid and the magnetocaloric elements, the performance of the heat exchangers, etc.
[0003] Today, developments focus on optimizing these generators with a view, on the one hand, to enabling their mass production and, on the other hand, to guaranteeing them a long service life. In addition to achieving usable energy efficiency, these generators must have a relatively small size or footprint to be integrated into commercial applications with space constraints.
[0004] Publications WO2009 / 087310 and WO2015 / 079313 belonging to the Manderesse provides an overview of the technical developments already made to magnetocaloric generators, which can be further improved. Description of the invention
[0005] The present invention aims to provide a new generation of magnetocaloric generators designed to optimize generator performance, reduce energy consumption, customize the generator's technical characteristics to achieve the intended objectives, and thus meet a wide range of applications: heating, cooling, air conditioning, reversible heat pumps, and reversible converters enabling the conversion of electrical and / or mechanical energy into thermal energy and, conversely, the conversion of thermal energy into mechanical energy. and / or electric.
[0006] To this end, the invention relates to a generator of the type indicated in the preamble, characterized in that said magnetic arrangement comprises two superimposed magnetic rotors, of which an external magnetic rotor and an internal magnetic rotor delimiting between them an air gap, in that said external magnetic rotor and said internal magnetic rotor have the same number of magnetic poles, in that said set of active elements comprises a stator disposed in said air gap, in that said active elements extend axially in said stator between a hot end and a cold end of said generator, and in that one of said external or internal magnetic rotors is coupled on the one hand to an electrical machine by a mechanical coupling, and on the other hand to the other of said internal or external magnetic rotors by a magnetic coupling.
[0007] In a preferred embodiment of the invention, said generator has a cylindrical configuration, the external and internal magnetic rotors are concentric around an axis of rotation, and said stator has an annular shape, concentric with said external and internal magnetic rotors.
[0008] Said external magnetic rotor is preferably coupled to said electrical machine. In this case, it comprises a toothed ring, and said mechanical coupling between said external magnetic rotor and said electrical machine comprises a toothed belt transmission engaging said toothed ring.
[0009] In the preferred embodiment of the invention, said generator comprises at least means for guiding the rotation of said external magnetic rotor and of said internal magnetic rotor carried by a housing, and said means for guiding the rotation of said external magnetic rotor comprise peripheral guiding elements, mounted in the ends of said external magnetic rotor and arranged to travel on a guide path belonging to said housing.
[0010] Said guiding elements are advantageously mounted on said external magnetic rotor in peripheral sectors located outside said magnetic poles. And said guiding path is advantageously provided on a guide ring attached to said housing, said guide ring being able to be made of a material with a hardness greater than that of the material of said housing.
[0011] Most advantageously, said magnetic arrangement is of modular construction and comprises an assembly of at least two superimposed elementary modules, each elementary module comprising a slice of said external magnetic rotor and a slice of said internal magnetic rotor and the number of elementary modules of said magnetic arrangement is determined according to the power and / or the target temperature difference for said generator.
[0012] Said elementary modules preferentially comprise shapes complementary interlocking mechanisms arranged to center the said elementary modules with respect to the axis of rotation and to index the angular position of the said elementary modules with respect to each other.
[0013] According to variant embodiments of the invention, said magnetic arrangement may further comprise a magnetic field uniformization device superimposed on said magnetic poles of said external magnetic rotor and / or said internal magnetic rotor.
[0014] In the preferred embodiment of the invention, said active elements are porous and each traversed by a heat transfer circuit allowing alternating axial circulation of a heat transfer fluid from said hot end to said cold end in a first operating cycle and vice versa from said cold end to said hot end in a second operating cycle of said generator. In this case, the axial orientation of the heat transfer fluid circulation is advantageously perpendicular to the radial orientation of the magnetic field lines generated by said magnetic poles of said magnetic arrangement.
[0015] Preferably, the number of active elements of said assembly is a multiple of the number of magnetic poles of said magnetic arrangement, and said active elements are arranged side by side on the circumference of said stator.
[0016] Each active element may include a longitudinal material carrier housed within the stator. In this case, the material carriers may have a cross-section chosen from a square, a rectangle, or a trapezoid. Furthermore, the length of the material carriers is advantageously determined according to the power and / or the target temperature difference for the generator.
[0017] In the preferred embodiment of the invention, the material holder of each active element comprises an internal housing arranged to receive at least one MMC material, and at least one fluidic connection at each of its ends, arranged to connect said active element to said heat transfer circuit. It may further comprise at least one distributor in each end zone between said fluidic connection and said internal housing.
[0018] Said active elements may comprise at least one porous MMC block of at least one MMC material in the form of blades or regular material structures oriented parallel to the longitudinal axis of said material carrier, extending radially, and spaced apart from each other by an interval, the intervals constituting a set of channels allowing the bidirectional axial circulation of said heat carrier.
[0019] Said active elements may comprise several porous MMC blocks of the same MMC material or of different MMC materials separated from each other by joining spacers, the different MMC materials being arranged preferentially according to an increasing or decreasing Curie temperature evolving continuously. Brief description of the drawings
[0020] The present invention and its advantages will become more apparent from the following description of several embodiments given by way of non-limiting examples, with reference to the accompanying drawings, in which:
[0021] [Fig-1] is a perspective view of a magnetocaloric generator according to the invention, represented by its magnetic arrangement and its rotational drive system,
[0022] [Fig.2] is a perspective view of part of a magnetic arrangement and a support for active elements belonging to a generator according to the invention,
[0023] [Fig.3] is a side view of a generator according to the invention, represented by its magnetic arrangement and its active elements,
[0024] [Fig.4] is a perspective view of a magnetic arrangement of a generator according to the invention, consisting of an assembly of two elementary modules,
[0025] [Fig.5] is an exploded perspective view of an elementary module of [Fig.4],
[0026] [Fig.6] is a simplified side view of a generator according to a variant of the invention, and similar to [Fig.3],
[0027] [Fig.7] is an exploded view of an active element of a generator according to the invention,
[0028] [Fig.8] is a longitudinal cross-sectional view of the active element of [Fig.7], and
[0029] [Fig.9] is a perspective view of a generator according to the invention, faired and seen from an axial end comprising a control system for the heat transfer circuit. Description of the implementation methods
[0030] In the illustrated embodiments, identical elements or parts bear the same reference numbers. Furthermore, terms with a relative meaning, such as vertical, horizontal, right, left, front, back, above, below, etc., should be interpreted under normal conditions of use of the invention, as shown in the figures. The X, Y, and Z axes are defined by an orthonormal coordinate system illustrated in [Fig. 1]. Moreover, the geometric positions indicated in the description and claims, such as "perpendicular," "parallel," and "symmetrical," are not limited to the strict geometric sense but extend to geometric positions that are close, i.e., that allow a certain tolerance within the technical field considered, without affecting the result obtained.This tolerance is notably introduced by the adverb "sensible", without this term necessarily being repeated before each adjective.
[0031] With reference to the figures, the magnetocaloric generator 1 according to the invention, also referred to hereafter as "generator 1", comprises a set of active elements 2 based on magnetocaloric material and a magnetic arrangement 3, movable rela tively relative to each other. In the preferred embodiment of the invention shown, the magnetic arrangement 3 is movable relative to the set of active elements 2, which is fixed, thus greatly simplifying the heat transfer system. The generator 1 further includes a heat transfer circuit for thermally coupling the active elements to at least one external device or application (not shown) via at least one heat exchanger (not shown), as described, for example, in the publications cited above. The heat transfer circuit may include a heat transfer fluid or a solid heat transfer fluid (not shown).The invention relates particularly to the production of heat and / or cold from mechanical or electrical energy, using the magnetic phase transition properties of magnetocaloric materials, hereafter referred to as MMC materials, under the effect of a magnetic field variation near their transition temperature, known as the Curie temperature (Te). It also relates to the conversion of thermal energy into mechanical or electrical energy, using the same properties of MMC materials under the effect of a temperature variation. Thus, the generator 1 of the invention constitutes an energy conversion machine that can be reversible, that is to say, that can operate in two opposite modes depending on the input energy.
[0032] In the example shown, the generator 1 is depicted in a cylindrical configuration, and the magnetic arrangement 3 comprises or is formed of two superimposed and concentric magnetic rotors about an axis of rotation A along X, including an external magnetic rotor 4 and an internal magnetic rotor 5 defining between them an annular interval, called an air gap E. The external magnetic rotor 4 and the internal magnetic rotor 5 have the same number of magnetic poles PM, including at least two magnetic poles PM (Figures 3 and 6), four magnetic poles PM (Figures 1, 4, 5), or more than four magnetic poles PM as required. The magnetic poles PM of each rotor 4, 5 are evenly distributed around the circumference of each of the rotors 4, 5, each extending over an angular sector of the same value, and occupying approximately half the circumference of the rotor 4, 5.The remaining half of the circumference of the rotor 4, 5 is occupied by empty areas (outside the magnetic field) (Figures 1 and 6) or by magnetically and electrically insulating material ([Fig. 3]). Furthermore, the magnetic poles PM of the two rotors 4, 5 are aligned in pairs to generate continuity of the magnetic field lines in each pair of magnetic poles PM of the outer magnetic rotor 4 and the inner magnetic rotor 5. Thus, the magnetic field lines are concentrated in the air gap E between each pair of magnetic poles PM. Each magnetic pole PM comprises or is formed from one or more magnetic generators 6, 7, such as permanent magnets, electric currents, etc. tromagnets, superconductors, or any other compatible magnetic generator. If they comprise or are formed of several magnetic generators 6, 7, as shown in figures 1, 3, 6, then they are joined together to create a continuous and unbroken PM magnetic pole.
[0033] In an embodiment illustrated in [Fig. 6], the magnetic arrangement 3 further comprises a magnetic field uniforming device 8 arranged to uniformize and regulate the magnetic field produced by the magnetic poles PM, and consequently to increase the magnetic performance of the magnetic poles PM and thus the efficiency and power of the generator 1. For example, the magnetic performance of the magnetic poles PM can be increased by at least 30%, without this value being limiting. In the example shown, the magnetic field uniforming device 8 is in the form of a sheet or plate, arranged to cover the end of each of the magnetic poles PM of the external magnetic rotor 4 and / or the internal magnetic rotor 5 opposite the air gap E.The magnetic field uniforming device 8 may have any other shape favorable to uniforming the magnetic field in the magnetic field zone of the air gap E, without any shape limitations, such as a prismatic shape, etc. The uniforming device 8 is profiled to approximate the shape of the profile of the magnetic poles PM and / or the active elements 4. It may be attached to the ends of the magnetic poles PM by bonding or any other equivalent permanent fixing method. The uniforming device 8 may be made of low-carbon steel, pure iron, and any other ferromagnetic material. By way of example, it may have a thickness from 2 mm to 5 mm, constant or variable, and this range of values is not limiting.
[0034] The external magnetic rotor 4 and the internal magnetic rotor 5 are coupled to rotate synchronously around the axis of rotation A. They can be coupled by a mechanical transmission, such as a gear train, a belt and pulley system, a chain and sprocket system, or similar. They can be coupled by an electronic transmission if each rotor is coupled to a motor. They can also be coupled magnetically, i.e., without contact, thus avoiding efficiency losses due to friction.
[0035] In the preferred embodiment of the invention, the external magnetic rotor 4 is driven in rotation by an electric machine 9 and in turn drives the internal magnetic rotor 5 by magnetic coupling, as shown in [Fig. 1]. Of course, the reverse configuration can be used, i.e., the internal magnetic rotor 5 is driven by the electric machine 9 and in turn drives the external magnetic rotor 4 by magnetic coupling. However, the efficiency of the magnetic coupling is significantly greater in the example shown because the mechanical inertia of the rotor external genetic 4 is more important than that of the internal magnetic rotor 5. Thus, an external mechanical drive makes it possible to limit oscillatory phenomena in the case of drive by magnetic coupling of the internal magnetic rotor 5.
[0036] The electric machine 9 can be any type of motor or alternator, depending on the operating mode of the magnetocaloric generator. In the example shown, the electric machine 9 is coupled to the external magnetic rotor 4 by a mechanical transmission. Also in the example shown, this mechanical transmission preferably comprises a toothed belt 10 that meshes with a toothed ring 11 located on the periphery of the external magnetic rotor 4. Of course, any other type of mechanical transmission can be used, but the toothed belt 10 transmission has the advantage of being precise, reliable, stable, and quiet. Furthermore, the reduction ratio between the toothed pulley 12 at the output of the electric machine 9 and the toothed ring 11 of the external magnetic rotor 4 is significant and eliminates the need for a gearbox between the electric machine 9 and the external magnetic rotor 4, further improving the energy efficiency of the generator 1.The electrical machine 9 can thus be dimensioned optimally to achieve the optimal operating point of the generator 1.
[0037] The two rotors 4, 5 are guided in rotation about their axis A by guiding means carried by a housing C ([Fig. 9]). They are also blocked in translation along X by any suitable locking means (not shown). The internal magnetic rotor 5 can be guided in rotation by any known means, and for example by means of two bearings 13 provided in its end zones ([Fig. 1]). The external magnetic rotor 4 is preferably guided in rotation by a series of small guiding elements 14, relative to the average diameter of said rotor, arranged peripherally and fixed in the ends of said rotor. In the example shown, the guiding elements 14 are in the form of rotating rollers arranged to run on a guide track belonging to the housing C ([Fig. 9]).This solution is particularly advantageous because it allows for frictionless, efficient, and reliable rotary guidance of the external magnetic rotor 4, which does not generate heat and therefore does not consume energy. Furthermore, this solution is economical given the low cost of this type of guide element 14, which are commercially available parts, and universal because it is suitable for all sizes of the generator 1, and therefore for all diameters of the external magnetic rotor 4. However, this example is not exhaustive, and any other type of equivalent or suitable guide element, such as low-friction pads, may be suitable. In addition, the peripheral arrangement of the guide elements 14 frees up the entire central part of the generator 1, particularly its hot end EC and cold end EF, to accommodate the heat transfer circuit ([Fig. 9]). This arrangement allows for greater compactness of the generator. nerator 1.
[0038] The guide elements 14 can be arranged regularly around the periphery of the external magnetic rotor 4 ([Fig. 1]), or preferably outside the magnetic poles PM (Figures 2 and 3), which facilitates their mounting and ensures frictionless operation. The guide elements 14 can be mounted on flanges 16 attached to the ends of the external magnetic rotor 4. The guide path can be provided directly on the housing C or in a guide ring 15 attached to the housing C. The guide ring 15 can thus be made of a material different from that of the housing C, and in particular a material with a greater hardness than that of the housing C, such as a stainless steel guide ring for an aluminum housing C, without this example being limiting, allowing for optimization of the choice and costs of raw materials according to their function.The arrangement of the guide elements 14 also allows for the balancing of axial forces. The guide path or guide ring 15 can further be configured to form means for blocking the translation along X of the external magnetic rotor 4, with or without friction.
[0039] The magnetic arrangement 3 can be of monobloc construction or, preferably, of modular construction, in accordance with the illustrated embodiment. The modular construction facilitates and streamlines the manufacture of the generator 1 to meet the specifications and intended applications, allowing the generator 1 to be lengthened without increasing its diameter. With reference to Figures 1, 2, 4, and 5, the magnetic arrangement 3 comprises an assembly of at least two axially superimposed elementary modules 17. The number of elementary modules 17 in the magnetic arrangement 3 determines its length, which is itself determined based, in particular, on the power and / or the target temperature difference for the generator 1.
[0040] Each elementary module 17 comprises a slice of the external magnetic rotor 4 and a slice of the internal magnetic rotor 5. Naturally, the elementary modules 17 of each rotor are handled separately, since the two rotors are physically independent parts. More specifically, [Fig. 4] illustrates an assembly of two superimposed elementary modules 17 of the two rotors 4, 5 shown without the magnetic generators 6, 7.
[0041] Figure 5 illustrates an elementary module 17 showing only the external magnetic rotor 4 depicted without the magnetic generators 6. Each elementary module 17 comprises the magnetic frame 18 of the external magnetic rotor 4, which can be made in one piece or in several pieces, such as cut and electrically insulated sheets to prevent the formation of eddy currents resulting from the variation in magnetic flux caused by the active elements 2. In the example As shown, the magnetic frame 18 is made up of a plurality of elementary magnetic sheets 19, ranging in size from a few millimeters to a few centimeters, for example, between 0.5 mm and 10 mm, although these values are not limiting. The elementary magnetic sheets 19 are cut or stamped, stacked axially, and assembled together by fasteners (not shown) through holes 20 provided in corresponding tabs 21. Of course, any other equivalent fastening method may be suitable. The manufacturing method of stacking elementary magnetic sheets 19 optimizes production tools and the amount of raw material used, resulting in greater flexibility in the design of the magnetic assembly 3 and a lower overall production cost. The length of the elementary modules 17 can thus be adjusted according to requirements.
[0042] The elementary modules 17 of each rotor further comprise complementary interlocking forms arranged to center the elementary modules 17 with respect to the axis of rotation A and to index the angular position of the elementary modules 17 relative to each other. In the example illustrated in Figures 4 and 5, each elementary module 17 of the external magnetic rotor 4 is framed by two end magnetic plates 22, which may have a thickness greater than that of the elementary magnetic plates 19, and which comprise the complementary interlocking forms. These complementary interlocking forms comprise, in one of the end magnetic plates 22 of each elementary module 17, a male interlocking form, in the form of a projecting rib 23 axially facing outwards from said module, divided into four angular sectors regularly distributed between the magnetic poles PM of the external magnetic rotor 4.Correspondingly, in the opposite end magnetic sheet 22 of each elementary module 17, the complementary interlocking forms comprise a female interlocking form, in the form of a groove 24 projecting axially facing inwards said module, divided into four angular sectors regularly distributed between the magnetic poles PM of the external magnetic rotor 4. Of course, any other equivalent complementary interlocking form may be suitable, including any other means of centering and indexing.
[0043] The elementary modules 17 forming all or part of the magnetic arrangement 3 are further assembled together by means of fasteners (not shown) such as threaded rods, bolts, tie rods, screws, through holes 25 provided in corresponding lugs 26 ([Fig. 4]). Of course, any other equivalent fastening means may be suitable. To simplify assembly, the elementary modules 17 may be assembled together in groups of two, and then the groups of two may in turn be assembled together by means of intermediate flanges, as shown in [Fig. 1]. Any other assembly method may also be suitable.
[0044] The elementary modules of the internal magnetic rotor 5 are not shown, but also include complementary interlocking, centering, and indexing features, as well as fastening means. By way of example, indexing pins and through holes for screws may be mentioned, enabling both the fastening and the relative positioning of the elementary modules relative to each other. Any other equivalent complementary interlocking feature and any other equivalent fastening means may be suitable.
[0045] With particular reference to Figures 2, 3 and 6, the set of active elements 2 of the generator 1 of the invention comprises or is formed of a fixed annular stator 30, centered on the axis of rotation A along X, disposed in the air gap E between the external magnetic rotor 4 and the internal magnetic rotor 5. The active elements 2 extend axially within the stator 30 between a hot end EC and a cold end EF of the generator 1, symbolically represented in Figures 2 and 7. The active elements 2 are porous and each is traversed by a passive magnetocaloric heat transfer fluid via a heat transfer fluid circuit, which allows axial and alternating circulation along X of said heat transfer fluid from said hot end EC to said cold end EF and vice versa so as to carry out the magneto-thermodynamic cycles within the generator 1.
[0046] The axial circulation along X of the heat transfer fluid is therefore perpendicular to the radial orientation of the magnetic field lines generated by the magnetic poles PM of the magnetic arrangement 3. This arrangement is particularly advantageous because it allows the active elements 2 to carry out the magneto-thermodynamic cycles by the alternating movement synchronous with the variations of the magnetic field.
[0047] The active elements 2 are preferably arranged side by side on the circumference of the stator 30 to maximize the amount of MMC material present in the volume of the air gap E. For this purpose, the space between two consecutive active elements 2 is chosen to be as narrow as possible in order to minimize the volume of non-magnetocaloric material in the magnetic circuit arranged in the air gap E, promote the smoothest and most continuous possible rotational movement of the magnetic arrangement 3, requiring the most uniform possible rotational torque, and inducing a reduction in energy consumption.
[0048] The active elements 2 are further distributed regularly, separated from each other by a fixed spacing, and the number of active elements 2 is preferably a multiple of the number of magnetic poles PM of the magnetic arrangement 3. Thus, at each moment of each thermodynamic work cycle, the active elements 2 are divided into two equal groups: one group of active elements 2 located in the areas under the magnetic field of the magnetic poles PM and one group of active elements 2 located in areas outside the magnetic field, outside the PM magnetic poles. This particular arrangement within generator 1 allows for a good distribution between areas under the field and areas outside the field, and thus to optimize the thermodynamic cycle.
[0049] With particular reference to Figures 7 and 8, each active element 2 is in the form of an independent bar and includes a longitudinal material holder 32 along X, arranged to be housed axially in the stator 30 and more particularly in a support 33 included in or forming said stator 30. An example of a support 33 is shown in [Fig. 2] and includes mounting rails 34 extending axially along X and regularly distributed around the circumference of the stator 30. The mounting rails 34 are each defined by a U-shaped wall, although this shape is not limiting. They are thus separated from each other to thermally insulate the active elements 2 from one another while remaining contiguous with respect to each other.The support 33 is preferably made of a thermally insulating, magnetically neutral, and electrically non-conductive material, such as, by way of non-limiting example, a synthetic polymer-based material, a carbon fiber-based composite material, stainless steel, a natural silica-based or resin-based material, or similar. In the example shown in [Fig. 2], the support 33 is formed from a single annular piece. This example is not limiting, as the support 33 can be formed from several pieces assembled side by side, each piece extending over an annular sector, which may correspond to the annular sector of the magnetic poles PM.
[0050] In the example shown, the support 33 of the stator 30 has a length greater than that of the rotors 4, 5 to provide at least one fixing zone ZF located outside the magnetic arrangement 3, at least at one end of said stator 30. Thus the material holders 32 can be easily inserted into and removed from the stator 30, and can also be fixed by screws or any other removable fixing device, in fixing holes 36 provided for this purpose in the material holders 32 and the support 33. Quick fixing means by clip or similar may also be suitable.
[0051] The material holders 32 have a cross-section chosen from a square, a rectangle, or a trapezoid. In the example shown, the cross-section of the material holders 32 is trapezoidal to optimize the usable volume of the stator 30. The length of the material holders 32 depends on the length of the magnetic arrangement 3, which is determined according to the power and / or the target temperature range for the generator 1. The longitudinal design along X of the magnetic arrangement 3 and the active elements 2 is advantageous since it facilitates and streamlines the manufacturing of the generator 1 to meet the specifications and intended applications, in varying temperature ranges, without increasing its diameter. playing on the number of elementary modules 17 of the magnetic arrangement 3 assembled in series.
[0052] The material carrier 32 of each active element 2 has an internal housing 35 arranged to receive at least one porous MMC material forming a set of channels 31 allowing the bidirectional axial circulation of the heat transfer fluid through said at least one MMC material. In the example shown, the heat transfer fluid is a fluid. The material carrier 32 then further includes at least one fluid connection 37, 38 at each of its ends to connect the active element 2 to the heat transfer circuit (not shown). In the example shown, the material carrier 32 has two fluid connections 37, 38 at each of its ends, corresponding respectively to a fluid inlet 37 and a fluid outlet 38. Since the active elements 2 are fixed, the fluid connections 37, 38 are advantageously simple, non-rotating, and therefore leak-proof connections, as they are not susceptible to generating leaks.The material carrier 32 also includes a distributor 39 in each end zone between the fluid connection(s) 37, 38 and the inner housing 35 to distribute the heat transfer fluid in the channel assembly 31.
[0053] In the example shown, the MMC material contained in each material holder 32 is in the form of one or more porous MMC blocks 40. Each porous MMC block 40 consists of material strips or other regular material structures. In each porous MMC block 40, the material structures 41 are preferably oriented axially along X parallel to the longitudinal axis B of the material holder 32 and extend radially parallel to the magnetic field lines in the air gap E. The axial orientation along X of the material structures 41 allows the alternating circulation of the heat transfer fluid between the cold end EF and the hot end EC of the generator 1. The radial orientation of the material structures 41 allows the eddy currents to be cut off and the local demagnetizing field to be reduced.
[0054] Furthermore, the material structures 41 are spaced apart by an interval (not visible), the intervals forming the set of channels 31 allowing the bidirectional axial circulation of the heat transfer fluid along X. The intervals between the material structures 41 form flat and narrow fluid passages that promote the laminar flow of the heat transfer fluid along X through the generator 1.
[0055] The porous MMC blocks 40 can be made from the same MMC material, or from different MMC materials. In this case, if the heat transfer fluid is a fluid, the porous MMC blocks 40 made of different MMC materials are preferably separated from each other by joining spacers 42. Similarly, the different MMC materials will preferably be arranged according to an increasing Curie temperature (Te) from a cold source located at the cold end EF to a hot source located at the hot end EC, to allow the Te to match the temperature gradient (difference) of the tem. pérature, formed in the volumes of MMC material of generator 1.
[0056] In an unrepresented variant, the MMC material contained in each material carrier 32 can also be in the form of one or more porous MMC blocks, obtained by sintering, for example, the pores constituting the fluidic passages for the heat transfer fluid.
[0057] The material holders 32 further include a cover 43 for sealing the inner housing 35. The material holders 32 and the mounting rails 34 provided in the support 33 may have axial translational guiding means (not shown) in their corresponding walls, such as grooves, ribs, or the like. The material holders 32 may also have axial translational assembly and / or guiding means (not shown) in their corresponding walls if they are mounted without the support 33.
[0058] The longitudinal configuration of the active elements 2 along X is particularly advantageous because it allows the fluid connections 37, 38, or any other thermal connection with the hot and cold sources, to be placed in one or both axial ends of the stator 30, as required. The fluid connections 37, 38 are then located near the distributors 44 ([Fig. 9]) provided in one or both axial ends of the generator 1, thus minimizing the length of the heat transfer circuit piping.
[0059] In the case of a heat transfer fluid, taken as an example and without limitation, the distributors 44 are controlled according to a switching frequency determined as a function of the frequency of the work cycles, synchronously with the magnetic field zones and the zones outside the magnetic field, by an actuator selected from among mechanical, hydraulic, electrical, and / or electronic actuators. The distributors 44 can be directly controlled by the rotation of the magnetic arrangement 3 by means, for example, of a cam 45 integral with the internal magnetic rotor 5, which allows the distributors 44 to be actuated by means of spools 46, as shown in [Fig. 9]. Any other equivalent means of controlling the distributors 44 may be suitable.
[0060] The longitudinal design along X of the active elements 2 therefore offers several advantages: facilitating the manufacture of the active elements 2 in the form of independent bars, simplifying the assembly and disassembly of the active elements 2 in the stator 30, standardizing components such as the porous MMC blocks 40, and reducing production costs, simplifying the heat transfer circuit and reducing pressure losses by shortening the piping.
[0061] In general, the longitudinal design along X of the magnetic arrangement 3 and the active elements 2 also makes it easy to increase the power and / or the operating temperature range of the generator by increasing the length of the magnetic arrangement 3 and the length of the active elements 2, therefore the total length of the generator 1, without increasing its radial dimension, which is advantageous in terms of compactness and size of the generator 1.
[0062] The generator 1 according to the invention is represented in a cylindrical configuration provided with a rotating magnetic arrangement 3, although this example is not limiting. A linear configuration is entirely conceivable, in which the stator 30 and the rotors 4, 5 are laid flat and the rotors 4, 5 are moved linearly, in reciprocating translation relative to the stator 30. Of course, the cylindrical configuration allows the rotors 4, 5 to be moved in a continuous rotational motion, which is much more energy-efficient, simpler, and less expensive to implement.
[0063] 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, within the limits of the appended claims. Furthermore, the technical features of the various embodiments and variants mentioned above may be combined, in whole or in part.
Claims
Demands
1. Magnetocaloric generator (1), comprising a set of active elements (2) based on MMC material, and a magnetic arrangement (3) arranged to be mobile relative to said set of active elements ^.characterized in that said magnetic arrangement (3) comprises two superimposed magnetic rotors, of which an external magnetic rotor (4) and an internal magnetic rotor (5) delimiting between them an air gap (E), in that said external magnetic rotor (4) and said internal magnetic rotor (5) have the same number of magnetic poles (PM), in that said set of active elements (2) comprises a stator (30) disposed in said air gap (E), in that said active elements (2) extend in said stator (30) between a hot end (EC) and a cold end (EF) of said generator, and in that one of said external magnetic rotors (4) or internal magnetic rotors (5) is coupled on the one hand to an electrical machine (9) by a mechanical coupling, and on the other hand to the other of said internal magnetic rotors (5) or external magnetic rotors (4) by a magnetic coupling.
2. Magnetocaloric generator (1) according to claim 1, characterized in that said generator has a cylindrical configuration, in that the external magnetic rotors (4) and internal magnetic rotors (5) are concentric around an axis of rotation (A), and in that said stator (30) has an annular shape, concentric with said external magnetic rotors (4) and internal magnetic rotors (5).
3. Magnetocaloric generator (1) according to claim 2, characterized in that said external magnetic rotor (4) is coupled to said electrical machine (9), in that it comprises a toothed ring (11), and in that said mechanical coupling between said external magnetic rotor (4) and said electrical machine (9) comprises a toothed belt transmission (10) engaging said toothed ring (11).
4. Magnetocaloric generator (1) according to claim 3, characterized in that said generator comprises at least means for guiding the rotation of said external magnetic rotor (4) and of said internal magnetic rotor (5) carried by a housing (C), and in that said means for guiding the rotation of said external magnetic rotor (4) comprise peripheral guide elements (14), mounted in the ends of said external magnetic rotor (4), and arranged to travel on a guide path belonging to said housing (C).
5. Magnetocaloric generator (1) according to claim 4, characterized in that said guiding members (14) are mounted on said external magnetic rotor (4) in peripheral sectors located outside said magnetic poles (PM).
6. Magnetocaloric generator (1) according to claim 4, characterized in that said guide path is provided on a guide ring (15) attached to said housing (C), said guide ring (15) being made of a material of greater hardness than that of the material of said housing (C).
7. Magnetocaloric generator (1) according to any one of the preceding claims, characterized in that said magnetic arrangement (3) is of modular construction and comprises an assembly of at least two superimposed elementary modules (17), in that each elementary module (17) comprises a slice of said external magnetic rotor (4) and a slice of said internal magnetic rotor (5), and in that the number of elementary modules (17) of said magnetic arrangement (3) is determined as a function of the power and / or temperature difference targeted for said generator (1).
8. Magnetocaloric generator (1) according to claim 7, characterized in that said elementary modules (17) have complementary interlocking forms arranged to center said elementary modules (17) with respect to said axis of rotation (A) and to index the angular position of said elementary modules (17) with respect to each other.
9. Magnetocaloric generator (1) according to any one of the preceding claims, characterized in that said magnetic arrangement (3) further comprises a magnetic field uniformization device (8) superimposed on said magnetic poles (PM) of said external magnetic rotor (4) and / or said internal magnetic rotor (5) and opposite said air gap (E).
10. Magnetocaloric generator (1) according to any one of the preceding claims, characterized in that said active elements (2) are porous and each traversed by a heat transfer circuit allowing alternating axial circulation of a heat transfer fluid from said hot end (EC) to said cold end (EF) in a first work cycle and conversely from said cold end (EF) to said hot end (EC) in a second work cycle of said generator, and in that the axial orientation of the heat transfer fluid circulation is perpendicular- dicular to the radial orientation of the magnetic field lines generated by said magnetic poles (PM) of said magnetic arrangement (3).
11. Magnetocaloric generator (1) according to claim 10, characterized in that the number of active elements (2) of said assembly is a multiple of the number of magnetic poles (PM) of said magnetic arrangement (3), and in that said active elements (2) are arranged side by side on the circumference of said stator (30).
12. Magnetocaloric generator (1) according to any one of claims 10 and 11, characterized in that each active element (2) comprises a longitudinal material carrier (32) housed in said stator (30), in that the material carriers (32) have a cross-section selected from a square, a rectangle, a trapezoid, and in that the length of said material carriers (32) is determined as a function of the power and / or the target temperature difference for said generator.
13. Magnetocaloric generator (1) according to claim 12, characterized in that the material carrier (32) of each active element (2) has an internal housing (35) arranged to receive at least one MMC material, and at least one fluidic connection (37, 38) at each of its ends, arranged to connect said active element (2) in said heat transfer circuit.
14. Magnetocaloric generator (1) according to claim 13, characterized in that said material carrier (32) further comprises at least one distributor (39) in each end zone between said fluidic fitting (37, 38) and said inner housing (35).
15. Magnetocaloric generator (1) according to any one of claims 10 to 14, characterized in that said active elements (2) comprise at least one porous MMC block (40) of at least one MMC material in the form of regular material blades or structures (41) oriented parallel to the longitudinal axis (B) of said material carrier (32), extending radially, and spaced apart from each other by an interval, the intervals forming a set of channels (31) allowing the bidirectional axial circulation of said heat transfer fluid.
16. Magnetocaloric generator (1) according to claim 15, characterized in that said active elements (2) comprise several porous MMC blocks (40) of the same MMC material or of different MMC materials separated from each other by joining spacers (42), the different MMC materials being arranged according to a Curie temperature (Te) increasing or decreasing, evolving continuously.