Machines that convert heat energy into electrical energy or electrical energy into heat energy.

Abstract

This invention relates to a machine (1) for converting thermal energy from free thermal deposition into electrical energy. The machine utilizes the magnetic phase transition properties of a specific material under temperature variations relative to its Curie temperature (Tc). The machine includes a magnetocaloric converter (2) having a fixed stator (S) and a movable rotor (R). The fixed stator (S) has an actuating element (4) made of the material, and the movable rotor has magnetic poles (5) and non-magnetic poles (5'). The machine includes a closed fluid loop (6) for heat transfer fluid connected via heat exchangers (E1, E2) to two heat sources (S1, S2) at different temperatures (T1, T2) and to the stator (S) to transfer the collected thermal energy to the actuating element (4). A synchronization system allows the actuating element (4) to undergo alternating thermal cycles to create a permanent magnetic imbalance between the rotor (R) and the stator (S), and to generate motion of the rotor (R) that produces mechanical energy that can be converted into electrical energy. The converter (1) can also be operated in reverse, i.e., as a magnetic cooling generator.

Description

Technical Field

[0001] The present invention relates to a machine that converts thermal energy into electrical energy or vice versa, the converter including at least one magnetothermal converter configured to convert temperature changes into mechanical energy or magnetic field changes into thermal energy.

[0002] This invention is particularly concerned with converting heat (including waste heat) into electrical energy. "Heat" refers to all heat sources (i.e., temperatures above absolute zero (>0 Kelvin)). This invention relates even more specifically to heat with temperatures between -100°C and +100°C.

[0003] This invention also focuses on using technologies developed for converting waste heat to generate heat energy from mechanical or electrical energy. Therefore, this invention relates to a reversible converter, specifically a reversible converter capable of operating in two reverse operating modes. Background Technology

[0004] Waste heat (also known as fleeting energy) refers to thermal energy generated through methods that are not the primary purpose, and in which the heat generated is not recovered but released into the atmosphere or any other environment. According to a study conducted by ADEME (the French Agency for Ecological Transition) in September 2017, French industry has a waste heat potential of 109.5 TWh (watt-hours), representing 36% of French industrial fuel consumption, of which 56.6 TWh is lost below 100°C. In addition, wastewater treatment plants, household waste incineration plants, data centers, hospitals, and other tertiary sites also release 8.4 TWh of heat.

[0005] In industry, we can cite the combustion process of combustibles in a furnace as an example, where only 20% to 40% of the energy is usable. Therefore, if not recovered, the remaining 60% to 80% of the heat generated by this furnace is waste heat. This example extends to all other heat sources, including thermal power plants, nuclear power plants, cement plants, solar thermal power plants, and gas liquefaction processing (this list is not exhaustive).

[0006] Depending on the industrial process, waste heat can take several forms: gaseous emissions (e.g., flue gas), liquid emissions (e.g., boiler emissions), or diffuse emissions (e.g., insulation leaks in thermal systems). Waste heat temperatures range widely, from -100°C to over +500°C.

[0007] For waste heat with temperatures above 150°C, there are many technologies for generating electricity through heat conversion (Rankin cycle, reverse thermoelectric conversion based on the Seebeck effect, molten salt, etc.). These technologies are particularly expensive and complex, and are not cost-effective or efficient enough to recycle waste heat with temperatures below 100°C (also known as “low-level heat emissions”).

[0008] For low-grade heat emissions, existing technologies offer only a low conversion rate of less than 30% compared to the Carnot cycle yield. Publications US 2015 / 0295469 A1 and US 9,998,036 B2 propose a technique based on magnetic phase change of certain metallic materials, but it is limited to using waste heat in the form of liquid emissions. This technique is difficult to implement, cumbersome, and very inefficient, thus limiting its application. In fact, for conversion rates of less than 20% compared to the Carnot cycle yield, this technique requires high liquid emission consumption. To date, it has not been developed industrially.

[0009] In the face of the challenges of energy transition, waste heat recovery and recycling from all sectors (industrial, service, and residential) represent significant energy-saving potential, thus substantially reducing the impact on global warming by drastically reducing heat loss into the atmosphere. Furthermore, waste heat is a widely available heat energy source worldwide.

[0010] Furthermore, there is currently no technology based on magnetic phase transitions of certain metallic materials that is reversible and capable of generating electrical energy from thermal energy in a first operating mode and generating thermal energy from electrical energy in a second operating mode, particularly for applications such as air conditioning, refrigeration, heating, tempering, drying, or similar applications. Summary of the Invention

[0011] The purpose of this invention is to overcome these drawbacks by proposing a reversible, industrializable, compact, reliable, and safe converter that meets standards in terms of magnetic field and pressure, implements a low-constraint, low-maintenance mechanism using a material-based magnetic phase change technique, and thus provides a long service life, offers a high conversion rate of over 60% compared to the Carnot cycle, without any negative impact on the environment or landscape, can utilize different forms of thermal energy deposits to generate green and renewable electricity, and can also generate magnetic cooling by means of a modular reversible technique that can be easily configured according to the target output and the temperature or cooling temperature of the energy deposit and / or the heating to be achieved.

[0012] Therefore, the present invention relates to a converter as defined in technical solution 1.

[0013] The compact design of the magnetocalor converter, in which the alternating configuration of the first and second sets of active elements distributed in the stator corresponds to the alternating configuration of the magnetic and non-magnetic poles of the rotor, allows for maximum utilization of all active elements and magnetic poles of the rotor and significantly improves the performance and thermal efficiency of the magnetocalor converter.

[0014] In a first embodiment, the magnetocaloric converter may include a fixed magnetic frame superimposed on the rotor to define an air gap between the rotor and the magnetic frame where the stator is located. The magnetic frame is configured to guide magnetic flux and close the field lines of the rotor's magnetic poles through the stator and the active element.

[0015] In a second embodiment, the magnetocaloric converter may include two stacked rotors to define an air gap between the two stacked rotors where the stator is located. The two rotors have the same number of magnetic and non-magnetic poles and are configured to guide magnetic flux and close the field lines of the magnetic poles of both rotors through the stator and the operating element. In this case, the two rotors may be connected by a mechanical connection or by magnetic coupling.

[0016] In a preferred embodiment of the invention, the stator includes or forms thermally insulating supports for fixing the actuating elements and fluid connections to allow communication between the fluid circuit and the actuating elements. The stator advantageously includes a plurality of actuating elements, which is several times the number of magnetic and non-magnetic poles of the at least one rotor, such that an equal number or equivalent quantity of actuating elements are opposite each magnetic and non-magnetic pole.

[0017] The fluid circuit may include a heat transfer fluid selected from the group consisting of aqueous solutions with or without additives, gaseous media, liquefied gas, and petroleum products. The fluid circuit may also include a pump, two heat exchangers, and two circulation loops for the heat transfer fluid connected in parallel via a synchronization system. In this case, the synchronization system is configured to alternately connect the operating elements from the first group and the second group, respectively, in series with the heat exchangers in one and the other circulation loops.

[0018] The synchronization system advantageously includes a fluid distributor that is controlled according to a switching frequency determined by an actuator selected from mechanical, hydraulic, electric, and / or electronic actuators. Alternatively, the fluid distributor may be controlled by at least one rotor of the magnetocaloric converter and a mechanical cam drive, by a variable-speed auxiliary motor and a mechanical cam drive, or by a programmable electric or electronic cam.

[0019] The fluid circuit may further include a heat transfer fluid buffer tank connected in series with each of the circulation loops. More preferably, the fluid circuit further includes a control unit for the circulation direction of the heat transfer fluid, the control unit being configured to circulate the heat transfer fluid in a single circulation direction in each of the heat exchangers.

[0020] The functional element may include at least one material selected from the group consisting of gadolinium (Gd), gadolinium (Gd) alloys, iron (Fe) alloys, manganese (Mn) alloys, and lanthanum (La), wherein the alloys include at least one material selected from the group consisting of silicon (Si), germanium (Ge), iron (Fe), magnesium (Mg), phosphorus (P), manganese (Mn), hydrogen (H), and arsenic (As), or a combination of some of the said materials. Furthermore, the material may be in the form of a sheet, porous block, sheet block, pellet, powder, or agglomerate.

[0021] In a preferred embodiment of the invention, the magnetocaloric converter has an annular configuration, with the stator and the at least one rotor radially stacked and extending axially. In this case, at least a portion of the fluid channel in the actuating element has an axial opening, and the fluid connector is disposed at at least one axial end of the stator.

[0022] In this annular configuration, the actuating elements are advantageously in the form of rods, extending axially in the stator, and each actuating element may comprise a porous material block or a layered sheet of material, defining the fluid channels between the actuating elements.

[0023] The magnetic poles of the at least one rotor can be obtained by magnetic components selected from the group consisting of one or more permanent magnets, ferrites, electromagnets, superconducting magnets, superconducting electromagnets, superconductors, and combinations thereof, while the non-magnetic poles of the at least one rotor can be obtained by non-magnetic components.

[0024] As a variant implementation, at least one of the magnetic poles of the stator or the at least one rotor may be offset relative to other symmetrical magnetic poles of the stator or the at least one rotor to introduce a permanent magnetic imbalance between the stator and the at least one rotor.

[0025] The converter may include several magnetocaloric converters connected in series, in parallel, or in a combination of series and parallel to increase the conversion power.

[0026] When the converter is designed to convert electrical energy into heat energy, it further includes an actuator connected to at least one rotor of the magnetothermal converter to subject the active element to a variable magnetic field and alternately generate magnetothermal heating and cooling cycles within the active element. In this case, the fluid loop is connected, on the one hand, to the stator to collect the heat energy generated by the active element, and on the other hand, to an external device via at least one heat exchanger to transfer the generated heat energy while simultaneously isolating the converter from the at least one external device. The magnetic modulation unit includes the at least one rotor and a synchronization system configured to synchronize the circulation of the heat transfer fluid in the active element with the magnetothermal cycle.

[0027] In this mode of operation, the active element can advantageously have an assembly of magnetothermal materials with different Curie temperatures organized in ascending or descending order.

[0028] When the converter is designed to convert thermal energy from a first heat source at a first temperature and a second heat source at a second temperature different from the first temperature into electrical energy, the converter further includes an electromechanical converter coupled to at least one rotor of the magnetocaloric converter to convert mechanical energy into electrical energy. In this case, the fluid circuit is coupled to the first heat source via a first heat exchanger and to the second heat source via a second heat exchanger to collect thermal energy while isolating the converter from the heat sources, and is coupled to the stator to transfer the collected thermal energy to the action element. The thermal modulation unit has a synchronization system configured to subject the action element to temperature changes, generating a permanent magnetic imbalance between the at least one rotor and the stator, and generating displacement of the at least one rotor to produce the mechanical energy.

[0029] In this operating mode, the electromechanical converter is a generator, the rotor of which is directly or by means of a reducer or multiplier connected to at least one rotor of the magnetocaloric converter to accommodate the speed of the rotor.

[0030] In this mode of operation, the invention also relates to the use of the above-defined machine for converting thermal energy into electrical energy to recover thermal energy generated from waste heat lost in a temperature range of -100°C to +100°C. Preferably, the temperature difference between the first heat source and the second heat source is at least 10°C. Furthermore, the converter is configured to achieve a conversion rate higher than 60% compared to the yield of a Carnot cycle. Attached Figure Description

[0031] The invention and its advantages will become more apparent from the following description of several embodiments provided as non-limiting examples, with reference to the accompanying drawings, in which:

[0032] - Figure 1 This diagram illustrates the principle used in this invention to convert thermal energy into mechanical energy that can be converted into electrical energy, based on the magnetic phase transition of metallic materials.

[0033] - Figure 2 This is an operation diagram of the converter according to the present invention.

[0034] - Figure 3 yes Figure 2 A plan view of the magnetocaloric converter of the machine.

[0035] - Figure 4 yes Figure 3 A three-dimensional view of the rotor of the magnetocaloric converter.

[0036] - Figure 5 A perspective view of the converter according to the invention, as seen from the fluid control side, is shown.

[0037] - Figure 6 This shows the view from the electromechanical converter side. Figure 5 A 3D diagram of the converter.

[0038] - Figure 7 This is an exploded view of a converter according to the present invention, which has two thermal stages, and...

[0039] - Figure 8 According to another implementation Figure 2 A plan view of the magnetothermal converter of the machine. Detailed Implementation

[0040] In the examples of the illustrated embodiments, the same elements or components have the same reference numerals. Furthermore, terms with relative meanings, such as vertical, horizontal, right, left, front, back, above, below, etc., must be interpreted under the normal conditions of use of the invention, as shown in the figures.

[0041] The converters 1 and 100 according to the present invention, capable of converting thermal energy into electrical energy, utilize a technique based on the magnetic phase transition of certain materials when subjected to a temperature change relative to their transition temperature Tc. The transition temperature Tc is the Curie temperature or Curie point at which a ferromagnetic (FM) material loses its magnetization. The material then becomes a paramagnetic (PM) material. Figure 1 The principle used in this invention is schematically illustrated. The magnetic phase change material M is schematically represented by a material rod, hereinafter referred to as the acting element 4, and is supported by or integrated into the fixed stator S. The magnetic phase change material M cooperates with a magnet A, such as a permanent magnet, to form the magnetic poles 5 of a movable rotor R that shifts or rotates relative to the stator S. Figure 1In the middle, the rotor R shifts according to arrow D. When material M is subjected to a temperature Tl higher than the transformation temperature Tc (in Figure 1 (on the left side), it changes from a ferromagnetic state to a paramagnetic state PM that has no effect on the two magnets A or the rotor R. Then, when the material M is subjected to a temperature T2 below the transition temperature Tc (in Figure 1 (On the right side), material M returns to the ferromagnetic state FM, where material M facilitates the flow of magnetic current between the two magnets A and creates magnetic imbalance with rotor R. Rotor R moves in the direction of arrow D to find a position of magnetic equilibrium. By repeating this thermal cycle at a defined frequency, rotor R will follow material M in the ferromagnetic state by following the thermal zone created by temperature changes. Then, the displacement of rotor R generates mechanical energy that can be converted into electrical energy. If rotor R as Figure 1 The diagram shows a linear relationship, meaning the displacement of rotor R can be alternating, or if rotor R is like other... Figures 2 to 8 If the rotor is rotating, then the displacement of the rotor R can be continuous.

[0042] The mechanical energy generated will depend on the properties of the material and its transition temperature Tc, the strength of the magnetic field of the rotor R, the number of magnetic poles 5, the frequency of the thermal cycle, and the difference between temperatures T1 and T2.

[0043] Materials exhibiting magnetic phase transitions can be selected from the group consisting of gadolinium (Gd), gadolinium (Gd) alloys, iron (Fe) alloys, manganese (Mn) alloys, and lanthanum (La), wherein the alloys include at least one material selected from the group consisting of at least silicon (Si), germanium (Ge), iron (Fe), magnesium (Mg), phosphorus (P), manganese (Mn), hydrogen (H), and arsenic (As). Furthermore, materials exhibiting magnetic phase transitions can be in various forms, such as those selected from the group consisting of planar or non-planar sheets, porous blocks, layered sheet blocks, granules, powders, and agglomerates.

[0044] The transition temperature (Tc) range of these materials allows for the efficient use of low-grade thermal deposits within a temperature range, for example, -100°C to +100°C. Furthermore, the difference between temperatures T1 and T2 can be small, and at least equal to 10°C.

[0045] Figure 2 The operation of a converter 1 according to the present invention is illustrated schematically. The converter 1 includes a magnetocaloric converter 2 and an electromechanical converter 3 connected to the magnetocaloric converter 2. The magnetocaloric converter 2 is configured to convert temperature changes into mechanical energy, and the electromechanical converter 3 is configured to convert mechanical energy into electrical energy E. The converter 1 also includes a thermal modulation unit configured to collect thermal energy from a first heat source S1 at a first temperature T1 and a second heat source S2 at a second temperature T2 different from the first temperature T1, and transfer the thermal energy to the magnetocaloric converter 2.

[0046] The magnetocalor 2 has a fixed stator S and a movable rotor R that rotates around an axis X. The fixed stator S is provided with a magnetic phase change material M constituting the active element 4, and the movable rotor R is provided with a magnet A constituting the magnetic pole 5. Figure 2 For the purpose of explaining the operation of machine 1, only two active elements 4 and two magnetic poles 5 are shown.

[0047] The heat modulation unit includes a closed and independent fluid loop 6 within the magnetocaloric converter 2. In practice, the fluid loop 6 is connected to the first heat source S1 via a first heat exchanger E1 and to the second heat source S2 via a second heat exchanger E2 to collect heat energy. Therefore, heat exchangers E1 and E2 have the advantage of isolating the fluid loop 6, as well as the magnetocaloric converter 2 and the entire converter 1, from the heat sources S1 and S2. The heat exchangers E1 and E2 can also be liquid / liquid, gas / gas, or liquid / gas exchangers, depending on the nature of the heat source and the heat transfer fluid. Thus, the converter 1 operates in a closed loop, i.e., in a dry environment, which allows for the full utilization of the available heat sources S1 and S2 without loss or waste, particularly in prior art solutions operating in humid environments.

[0048] Fluid circuit 6 is also connected to stator S to transfer the collected heat energy to operating element 4, stator S being placed in series with heat exchangers E1 and E2. For this purpose, fluid circuit 6 includes pump 7, which is configured to circulate the heat transfer fluid through heat exchangers E1 and E2 and operating element 4. The heat transfer fluid can include any fluid, liquid, or gas capable of transferring heat energy from one point to another without loss, such as aqueous solutions with or without additives, gaseous media, liquefied gases, etc., selected according to the machine's operating temperature. Depending on the operating conditions of the heat transfer fluid, the aqueous solution can be pure water or contain antifreeze additives (such as ethylene glycol) and / or corrosion inhibitors (such as soda ash) and / or any other additives.

[0049] The fluid circuit 6 includes two heat transfer fluid circulation loops 61 and 62 connected in parallel by a synchronization system. The synchronization system is configured to alternately connect the active element 4 in series with the heat exchangers E1 and E2 in one circulation loop 61 and the other circulation loop 62 to generate alternating thermal cycles at a defined frequency, thereby creating permanent magnetic imbalance between the rotor R and the stator S and causing displacement of the rotor R.

[0050] The synchronization system includes a fluid distributor 10 controlled according to a switching frequency determined by actuator 11. Fluid distributor 10 may include a two-way ball valve or a spool valve. Actuator 11 may be selected from mechanical actuators, hydraulic actuators, electric actuators, and / or electronic actuators. For example, actuator 11 may be separate from the magnetocaloric converter 2 and may include an auxiliary or dedicated variable-speed motor, and is coupled to fluid distributor 10 via a mechanical actuator. Actuator 11 may be integrated into the converter and may include the rotor R of the magnetocaloric converter 2, coupled to fluid distributor 10 via a mechanical actuator. In both examples, the mechanical actuator may advantageously be a cam actuator 26 (see...). Figure 5 The actuator 11 may also include an electric or electronic cam controlled by a programmable electronic card. These examples are, of course, non-limiting.

[0051] Fluid circuit 6 includes a buffer tank 8 for the heat transfer fluid connected in series with each of circulation loops 61 and 62. Fluid circuit 6 also includes a control unit 9 for the circulation direction of the heat transfer fluid in circulation loops 61 and 62, to apply a single circulation direction of the heat transfer fluid in heat exchangers E1 and E2, as indicated by arrow F. Control unit 9 may include a one-way valve, such as a ball valve, that allows fluid to pass through only in one circulation direction.

[0052] refer to Figure 2 This explains the function of converter 1. In the first thermal cycle, fluid distributor 10 is in the first position, as shown... Figure 2 As shown, the heat transfer fluid circulates from the buffer tank 8 via the pump 7 in the first circulation loop 61, shown as a solid line. The heat transfer fluid passes through the first heat exchanger E1 to recover thermal energy at a temperature T1 from the first heat source S1 and above the transition temperature Tc, and passes through the... Figure 2 The top-operating element 4 (which becomes paramagnetic, having no effect on magnet A (the unshaded magnet) of rotor R) recovers heat energy from the second heat source S2 at a temperature T2 below the transition temperature Tc via the second heat exchanger E2. Figure 2 The bottom element 4 becomes ferromagnetic, which facilitates the conduction of magnetic flux between the magnets A (shaded magnets) of the rotor R and causes the rotor R to rotate around the axis X, and then returns to the buffer tank 8.

[0053] In the second thermal cycle, the fluid distributor 10 is in Figure 2 The second location is not shown, and the heat transfer fluid circulates from the buffer tank 8 via the pump 7 in the second circulation loop 62, shown as a dashed line. The heat transfer fluid passes through the first heat exchanger E1 to recover thermal energy at a temperature T1 from the first heat source S1 and above the transition temperature Tc, and passes through the location... Figure 2The bottom element 4 (which becomes paramagnetic and has no effect on the magnet A of the rotor R) recovers heat energy from the second heat source S2 at a temperature T2 below the transition temperature Tc via the second heat exchanger E2. Figure 2 The top actuating element 4 becomes ferromagnetic, which facilitates the conduction of magnetic flux between the magnets A of the rotor R and causes the rotor R to rotate around the axis X, and then returns to the buffer tank 8.

[0054] The first and second thermal cycles repeat at a certain frequency by means of a synchronization system, which controls the switching of the fluid distributor 10 by generating alternation of paramagnetic and ferromagnetic phases in the action element 4 and by generating torque on the rotor R. The heat transfer fluid circulates in one direction in the action element 4 in the first circulation loop 61 and in the opposite direction in the second circulation loop 62, but always circulates in the same direction according to arrow F in the heat exchangers EL and E2.

[0055] Figure 2 The magnetocalor 2 in Figure 3 and Figure 4 The example shown is a rotary configuration, but it is still non-limiting. A linear configuration with the stator S and rotor R lying flat is quite feasible. Figures 5 to 7 As shown, the magnetocaloric converter 2 enters the converter 1. The active element 4 is supported by a ring-shaped or disc-shaped support 12 centered on the axis X. Figure 7 Support. The support member 12 forms an integral part of the fixed stator S or is an integral part of the fixed stator S. The rotor R is also annular or disc-shaped around the axis X, complementing the stator S. Figure 3 and Figure 4 In the example, rotor R comprises two radially stacked rotors 13 and 14 (an inner rotor 13 and an outer rotor 14, coaxial and centered on axis X), separated from each other by an air gap 15 housing the stator S. This configuration is not limiting, as the two rotors can also be axially stacked (see [reference]). Figure 7 This configuration allows for enhancement of the magnetic field in the air gap 15 and improves the magnetic drive efficiency of the rotor R through the alternating paramagnetic and ferromagnetic action elements 4. Because the action elements 4 are alternately opposed to the magnetic poles 5 (when they are in the paramagnetic phase) and to the non-magnetic poles 5' (when they are in the ferromagnetic phase), a permanent magnetic imbalance is generated in the rotor R. In this configuration where the stator S is housed in the air gap 15 between the two rotors 13 and 14, the magnetic effects of the rotors 13 and 14 and the magnetic effects of the action elements 4 have the advantage of combination and amplification, resulting in increased mechanical energy generation.

[0056] The inner rotor 13 and the outer rotor 14 have the same number of magnetic poles 5 and non-magnetic poles 5'. "Non-magnetic poles" are those that do not generate a magnetic field and do not actually contain magnets or ferrites or any other means of generating a magnetic field. Furthermore, for each rotor 13, 14, the number of magnetic poles 5 is equal to the number of non-magnetic poles 5'. The inner rotor 13 and the outer rotor 14 are coupled together to rotate synchronously. They can be coupled by mechanical transmissions, such as gear trains, belt and pulley systems, chain and sprocket systems, or the like. They can also be magnetically coupled together, thus not in contact. Figure 3 and Figure 4 In the example, the rotor R comprises four magnetic poles 5 and four non-magnetic poles 5' distributed alternately and regularly. Therefore, they extend in angular sectors of equal value. Of course, the number of magnetic poles 5 is not limited to four and can be equal to two (see [reference needed]). Figure 7 (or more than four.)

[0057] The inner rotor 13 is cylindrical and includes a central core 16, which is preferably non-magnetic or not very magnetic. The central core 16 can be hollow, open, permeable, or solid, and is made of a material such as aluminum, stainless steel, or the like. The inner rotor 13 includes magnets A, such as permanent magnets or ferrite, which are divided into four pairs of magnets A. The four pairs of magnets A are connected together by magnetic components 17 to form four magnetic poles 5 distributed at right angles to each other around the central core 16. The magnetic components 17 can be made of soft iron, soft steel, or the like. The magnetic components 17 can be supplemented by deflectors 18, which are preferably magnetizable, ferromagnetic, or magnetic. The deflectors 18 are disposed on the outer periphery of the inner rotor 13, aligned with the non-magnetic poles 5' and between two magnetic components 17, to guide and concentrate the magnetic flux Lc only in the magnetic poles 5 and the corresponding air gaps 15, thus limiting or even eliminating any field line leakage.

[0058] The outer rotor 14 includes a magnetic frame 19. The magnetic frame 19 may be made of soft iron, soft steel, or the like. The magnetic frame 19 supports magnets A or ferrite, divided into four groups of six magnets A each, to form four magnetic poles 5 distributed at right angles to each other. The non-magnetic poles 5' without magnets A may include preferably magnetizable, ferromagnetic, or magnetic deflectors 20, which are positioned on the inner periphery of the outer rotor 14 to guide and concentrate the magnetic flux Lc only in the magnetic poles 5 and the corresponding air gaps 15, thus limiting or even eliminating any field line leakage. Figure 3 The magnetic vector Vm and field line Lc are schematically shown. When passing through the air gap 15, stator S, magnetic poles 5 corresponding to the outer rotor 14, and magnetic frame 19, the magnetic flux generated by each magnetic pole 5 of the inner rotor 13 closes itself.

[0059] The magnetic poles 5 of the rotor R can advantageously comprise permanent magnets or ferrites, and each pole can be formed by one or more permanent magnets. Magnet A is selected to generate a magnetic flux density of at least 0.2 to 2 Tesla. The magnetic poles 5 may also include other magnetic field generators, such as those selected from the group consisting of magnetic components (a combination of permanent magnets and / or ferrites and magnetic parts), electromagnets, superconducting magnets, superconducting electromagnets, and superconductors. Therefore, the term "magnet A" as used in this specification extends to all embodiments of the magnetic field generator.

[0060] Figure 4 Only shown Figure 3 A perspective view of the rotor R (without the stator S). The frame 19 can be made of one or more parts, and for example, of four identical parts 19a, 19b, 19c, and 19d assembled in a complementary interlocking manner. Of course, any other construction is also suitable.

[0061] In a variant embodiment not shown, the rotor R may consist of only a single rotor. In this case, the converter 1 includes a fixed magnetic frame arranged opposite to the stator S and the rotor R to create an air gap for accommodating the stator S. The magnetic frame may be connected to the stator S. The magnetic frame may be made of soft iron, soft steel, or the like to guide the magnetic flux generated by the magnet A of the rotor R and close the field lines Lc on the magnetic poles 5 of the rotor R through the stator S.

[0062] In another variant embodiment, not shown, for the purpose of introducing permanent magnet imbalance between the stator S and the rotor R, at least one magnetic pole 5 of the stator S or the rotor R may be angularly offset relative to other magnetic poles 5, which are symmetrical about the axis X. This angular offset is performed during the construction of the rotor R or the stator S. In the case of a linear machine, the offset is introduced at the level of the spacing between the magnetic poles.

[0063] The stator S includes a plurality of active elements 4, determined according to the number of poles 5 and 5' of the magnetocaloric converter 2. More preferably, the number of active elements 4 is a multiple of the number of magnetic poles 5 and non-magnetic poles 5' of the rotor R, and this multiple can be equal to one. Figure 3 and Figure 4In the example shown, the number of active elements 4 is equal to twenty-four, and for the eight poles 5 and 5', the multiple is three. In this way, a distribution of three active elements 4 for each magnetic pole 5 and three active elements 4 for each non-magnetic pole 5' is obtained. The active elements 4 are distributed around the periphery of the stator S and are separated from each other by a spacing P, which is preferably regular and as small as possible to maximize the number of active elements 4 in the stator S. The active elements 4 are further assembled into a first group G1 and a second group G2. The active elements 4 of the first group G1 and the active elements 4 of the second group G2 alternate to create a magnetic alternation in the stator S between active elements 4 in a ferromagnetic state that favors the passage of magnetic flux and active elements 4 in a paramagnetic state that prevents the passage of magnetic flux. This alternating configuration corresponds to the alternating configuration of magnetic poles 5 and non-magnetic poles 5', as shown below. Figure 3 As shown. Furthermore, the magnetic alternation generated within the stator S varies according to the thermal cycle generated by the thermal modulation unit to create a permanent magnetic imbalance between the stator S and the rotor R, and to generate displacement of the rotor R to produce mechanical energy.

[0064] The support 12 for the stator S or the actuating element 4 is preferably made of a thermally insulating and magnetically neutral material, such as a polymer-based synthetic material, a carbon fiber-based composite material, stainless steel, a natural resin, or a silicone-based material or the like. The support 12 also includes a fluid connector 21 (see...). Figure 5 and Figure 6 The fluid circuit 6 is connected to the actuating element 4. The actuating element 4 is fixed, and the fluid connector 21 is a simple non-rotating connector. The fluid connector 21 forms a fluid inlet and a fluid outlet in or near each actuating element 4, and allows connection of pipes (not shown) forming fluid loops 61, 62. For this purpose, the actuating element 4 includes a fluid channel (not shown), which can be defined by a form selected from the group including holes, perforations, grooves, slits, voids, and combinations of these shapes. These forms can also be obtained by means of rolling, extrusion, machining, 3D printing, chemical, ionic or mechanical etching, forming, spacers between plates or sheets, spaces between particles, cavities in porous blocks, or combinations of these means. The fluid channel preferably has a small size between 0.01 mm and 5 mm, and preferably equal to 0.15 mm (capable of generating a heat transfer fluid flow through the actuating element 4), these values ​​are still non-limiting. A generally laminar flow is preferred.

[0065] In such Figures 3 to 6 as well as Figure 8In the case of the annular magnetocalor 2 shown, the stator S and rotors R, 13, 14 are radially stacked and extend axially parallel to axis X. Therefore, the actuating element 4 can take the form of a rod that also extends axially. The rod of the actuating element 4 can be obtained in various ways from a stack of porous blocks, perforated blocks, sheets, or plates that are separated from each other by spacers or any other similar means for creating fluid channels. The rod of the actuating element 4 advantageously has a parallelepiped geometry, comprising rectangular, thin sheets of the same material that are radially or axially stacked, parallel to each other, and separated by spacers forming the fluid channels. As an example, the material sheets can have a length between 10 mm and 150 mm, a height or width between 10 mm and 48 mm, and a thickness between 0.1 mm and 4 mm; these values ​​are still non-limiting. The material sheets are grouped together in a package of N sheets to form the rod of the actuating element 4, where N can be, for example, between 10 and 150; these values ​​are still non-limiting. Sheets of material from the same package can be held together by any suitable means, such as by local deformation of their thickness to create support points, spacers, U-shaped or L-shaped profiles, or dividing pieces made of adhesive with calibrated thickness. Thus, each actuating element 4 is formed as a single piece, which can be placed in an independent rectangular housing disposed in the stator S or support 12. This configuration allows for the independent disassembly of each actuating element 4 of the stator S without disassembling all actuating elements 4, which greatly simplifies the manufacture and implementation of the actuating elements 4.

[0066] The flat and narrow fluid channel has the advantage of facilitating laminar flow of the heat transfer fluid parallel to the axis X. Furthermore, the fluid channel allows the actuating element 4 to be axially open, enabling the fluid connector 21 to be positioned at at least one axial end of the stator S. The fluid connector 21 is located near the fluid distributor 10, minimizing the length of the fluid loop pipes 61 and 62. Therefore, this annular machine and rod-shaped actuating element construction offers several advantages: it facilitates the manufacture of the actuating element 4 as an independent rod, simplifies the overall assembly and disassembly of the actuating element 4 and the magnetothermal converter 2 in the stator S, standardizes components and reduces production costs, simplifies the fluid loop, and reduces pressure loss by shortening the pipes. This annular machine and rod-shaped actuating element construction also allows for easy increases in machine power by increasing the length of the rod of the actuating element 4 (and thus the length of the machine) without increasing its radial dimension, which is advantageous in terms of machine compactness and size. Of course, in the case of a linear and non-rotating machine, the annular construction of the magnetothermal converter 2 can be laid flat.

[0067] Figure 5 and Figure 6An example of a converter 1 according to the invention is shown, which is without a cover and provided with a base 22 that allows the machine to be fixed on any receiving surface. The electromechanical converter 3 coupled to the magnetocaloric converter 2 is preferably a generator configured to produce electrical energy E from the mechanical energy transferred by the rotor R of the magnetocaloric converter 2 (see [link to documentation]). Figure 2 Therefore, the generator rotor 23 is directly (see...) Figure 2 Alternatively, it can be connected to rotor R via a reducer or multiplier 24, allowing for the adaptation of two rotors 23 and R (see...). Figure 6 The speed of these. Figure 5 and Figure 6 The rotational guidance of the outer rotor 14 by means of rollers 25 on bearings is shown; this example is still non-limiting. Figure 5 A fluid synchronization and distribution system is further illustrated. The fluid synchronization and distribution system includes a fluid distributor 10 located at the axial end of the stator S and radially distributed around the axis X. In this example, the fluid distributor 10 is controlled by the rotor R of the magnetocaloric converter 2 via a cam drive 26, which allows the slide valves 27 of the fluid distributor 10 to be operated alternately. The switching frequency is automatically synchronized with the rotational speed of the rotor R. This example, as previously described, is non-limiting.

[0068] Figure 8 It is similar to Figure 3 The figure shows a magnetothermal converter 200 according to another variant embodiment of rotor R. In this example, rotor R also includes radially stacked inner rotor 13 and outer rotor 14, separated by an air gap 15, in which stator S and active elements 4 are housed. In this example, inner rotor 13 and outer rotor 14 are designed very simply because the magnetic poles 5 of each of rotors 13, 14 comprise magnets A or ferrite, and the non-magnetic poles 5' are empty. As in the previous example, the number of active elements 4 is a multiple of the number of magnetic poles 5 and non-magnetic poles 5', and for example equals 32, or 4 times the number of 8 magnetic poles.

[0069] Figure 7An exploded view of another example of a converter 100 according to the invention is shown, which is designed in a modular manner so that its structure can be adapted to the desired power output. The converter 100 includes two magnetocaloric converters 2 axially superimposed on axis X; this example is still non-limiting. In this case, two stators S are provided: one stator S in each magnetocaloric converter 2. This example is also non-limiting because the number of stators S or support members 12 can be greater than one. In this example, the construction of the rotor R and the stator S differs from the previous example. It is no longer annular but disc-shaped, which can also be suitable in some cases. The rotor R is disc-shaped, and each rotor includes two radially opposing magnetic poles 5 supported by magnetic plates 28. The two magnetic poles 5 alternate with two non-magnetic poles 5' that remain empty. The number of magnetic poles 5 is, of course, non-limiting and can be greater than two. Each magnetic pole 5 is formed by radially oriented magnetic components A. Each magnetocalor 2 has two identical rotors R, 130 and 140, which are axially stacked and mirror-arranged with respect to a plane perpendicular to axis X, defining an air gap 15 between them to house the stator S. Each stator S is also in the form of a disk and includes radially oriented magnetic poles 5 and non-magnetic poles 5', acting elements 4 (not shown). This modular assembly is assembled in a preferably non-magnetic housing 29, forming a cover, and supported by a base 22. Figure 5 and Figure 6 In the example, the fluid distributor 10 is located at the axial end of the stator S and is radially distributed around the axis X. In contrast to the previous example, the fluid channels in the actuating element 4 are radially open and require a larger diameter than the reference. Figures 3 to 6 as well as Figure 8 The illustrated annular structure includes a longer pipe connected to the fluid distributor 10. The fluid distributor 10 is controlled by the rotor R of the magnetothermal converter 2 via a cam actuator 26, which allows the slide valves 27 of the fluid distributor 10 to be actuated alternately. In this modular construction, the actuating elements 4 in the fluid circuit 6 can, of course, be connected in series, in parallel, or in a combination of series and parallel.

[0070] The converters 1, 100 according to the invention are advantageously reversible and can be operated in reverse to convert electrical energy into thermal energy. In this case, the converter utilizes the magnetothermal effect of certain materials, which involves the temperature change of a magnetic material subjected to an external magnetic field. This technique for generating magnetic cooling has been known for over thirty years, and we know the advantages it offers in terms of ecology and sustainability. It can use the same magnetic phase change materials as those described above, but utilize their magnetothermal effect. An example is specifically described in publication WO 2008 / 012411.

[0071] Furthermore, the magnetocaloric converters 2 and 200 are constructed and designed to utilize waste heat as efficiently as possible and have the highest possible output, making them particularly suitable for generating magnetic cooling. Therefore, Figures 2 to 8 The converters 1 and 100 shown can operate in a magnetically cooled mode, except that the generator 3 is replaced by an actuator (such as an electric motor or the like) connected to the rotor R to subject the acting element 4 to a variable magnetic field and alternately generate magnetothermal heating and cooling cycles within the acting element 4. The fluid circuit 6 remains the same, and the heat exchangers S1 and S2 become the heat exchanger and cooling exchanger of the magnetic cooler, respectively. All other components of the magnetothermal converters 2 and 200 are identical.

[0072] Furthermore, the active element 4 can comprise several types of magnetothermal materials that react at different temperatures, creating a thermal gradient along the active element 4. Therefore, the magnetothermal materials constituting the active element 4 can have different Curie temperatures organized in ascending or descending order, resulting in a larger temperature gradient. When the active element 4 is in the form of a rod, the rod can comprise continuous segments or blocks of different magnetothermal materials having ascending or descending Curie temperatures.

[0073] Of course, the present invention is not limited to the illustrated embodiments, but extends to any modifications and variations that are obvious to those skilled in the art, within the scope of the appended claims. Naturally, variations of one example of the embodiments are also applicable to other examples of the embodiments.

Claims

1. A converter (1) for converting thermal energy into electrical energy or vice versa, the converter comprising at least one magnetocaloric converter (2, 200) configured to convert temperature changes into mechanical energy or magnetic field changes into thermal energy, and at least one closed fluid loop (6) within the magnetocaloric converter (2, 200), the magnetocaloric converter (2, 200) comprising an action element (4) having a magnetic phase change or a thermal phase change, and a thermal modulation unit or a magnetic modulation unit configured to subject the action element (4) to temperature changes or magnetic field changes, the temperature... The change or magnetic field change has the effect of altering the magnetic state of the active element (4) or the temperature of the active element (4), respectively, wherein the heat transfer fluid circulates in a closed loop through the active element (4) and at least one heat exchanger, the closed fluid loop being configured to thermally connect the active element (4) to at least one external device by means of the at least one heat exchanger (E1, E2), the magnetothermal converter (2, 200) comprising a fixed stator (S) on which the active element (4) is disposed, the active element (4) being distributed in the stator (S) in a first magnetic state The magnetothermal converter (2, 200) comprises a first group (G1) of active elements (4) in a magnetic or thermal state and a second group (G2) of active elements (4) in a second magnetic or thermal state different from the first magnetic or thermal state. The first group (G1) of active elements and the second group (G2) of active elements alternate to create an alternation between active elements (4) in the first magnetic or thermal state and active elements (4) in the second magnetic or thermal state. The magnetothermal converter (2, 200) also includes at least one movable rotor (R, 13, 14) that is displaced or rotated relative to the stator (S). The rotors (R, 13, 14) are similarly provided with alternating and regularly distributed magnetic poles (5) and non-magnetic poles (5'), such that the magnetic poles (5) and non-magnetic poles (5') both extend on the same angular sector. The alternating configuration of the magnetic poles (5) and the non-magnetic poles (5') corresponds to the alternating configuration of the first group (G1) action element (4) and the second group (G2) action element (4), such that when the first group (G1) action element (4) faces the magnetic pole (5), the second group (G2) action element (4) faces the non-magnetic pole (5'), and vice versa.

2. The converter according to claim 1, characterized in that, The magnetocalor (2, 200) includes a fixed magnetic frame superimposed on the rotor (R) to define an air gap between the magnetic frame and the rotor (R) in which the stator (S) is disposed. The magnetic frame is configured to guide magnetic flux and close the field lines (Lc) of the magnetic poles (5) of the rotor (R) through the stator (S) and the action element (4).

3. The converter according to claim 1, characterized in that, The magnetocalor (2, 200) includes two rotors (13, 14) stacked to define an air gap (15) between them in which the stator (S) is configured. The two rotors (13, 14) have the same number of magnetic poles (5) and non-magnetic poles (5'). The two rotors (13, 14) are configured to guide magnetic flux and close the field lines (Lc) of the magnetic poles (5) of the two rotors (13, 14) through the stator (S) and the action element (4). The two rotors (13, 14) are connected together by mechanical connection or by magnetic coupling.

4. The converter according to any one of the preceding claims, characterized in that, The stator (S) includes or forms a thermal insulation support (12), the actuating element (4) and the fluid connector (21) are fixed on the thermal insulation support (12) to allow the fluid circuit (6) to communicate with the actuating element (4), and the actuating element (4) is distributed on the stator (S) and spaced apart from each other by a distance (P).

5. The converter according to claim 4, characterized in that, The spacing (P) is regular and as small as possible to maximize the number of active elements (4) in the stator (S).

6. The converter according to any one of claims 1 to 3, characterized in that, The stator (S) includes a plurality of action elements (4), the number of which is a multiple of the number of magnetic poles (5) and non-magnetic poles (5') of the at least one rotor (R, 13, 14).

7. The converter according to any one of claims 1 to 3, characterized in that, The fluid circuit (6) includes the heat transfer fluid selected from the group consisting of aqueous solutions with or without additives, gaseous media, liquefied gases, and petroleum products, and the actuating element (4) includes a fluid passage to allow the heat transfer fluid to circulate through the actuating element (4).

8. The converter according to any one of claims 1 to 3, characterized in that, The fluid circuit (6) includes a pump (7), two heat exchangers (E1, E2) and two circulation loops (61, 62) for the heat transfer fluid connected in parallel by a synchronization system, and the synchronization system is configured to alternately connect the active element (4) from the first group (G1) and the second group (G2) to the heat exchangers (E1, E2) in one circulation loop and the other circulation loop (61, 62) in series, and to generate alternation of thermal cycling or magnetothermal cycling at a determined switching frequency.

9. The converter according to claim 8, characterized in that, The synchronization system includes a fluid distributor (10) that is controlled according to the switching frequency determined by an actuator (11), the actuator (11) being selected from mechanical actuators, hydraulic actuators, electric actuators and / or electronic actuators, and the fluid distributor is configured to circulate the heat transfer fluid alternately in one direction in one circulation loop (61) and in the opposite direction in another circulation loop (62) in the actuating element (4).

10. The converter according to claim 9, characterized in that, The fluid distributor (10) is controlled by at least one rotor (R, 13, 14) of the magnetothermal converter (2) and a mechanical cam drive (26), by a variable speed auxiliary motor and a mechanical cam drive (26), or by a programmable electric or electronic cam.

11. The converter according to claim 8, characterized in that, The fluid loop (6) includes a buffer tank (8) for heat transfer fluid connected in series with each of the circulation loops (61, 62).

12. The converter according to claim 8, characterized in that, The fluid circuit (6) further includes a control unit (9) for the circulation direction of the heat transfer fluid, the control unit (9) being configured to circulate the heat transfer fluid in a single circulation direction in each of the heat exchangers (E1, E2).

13. The converter according to any one of claims 1 to 3, characterized in that, The active element (4) includes at least one of a magnetothermal material selected from the group consisting of gadolinium (Gd), gadolinium (Gd) alloys, iron (Fe) alloys, manganese (Mn) alloys, and lanthanum (La) alloys, wherein the alloy includes at least one of a material selected from the group consisting of silicon (Si), germanium (Ge), iron (Fe), magnesium (Mg), phosphorus (P), manganese (Mn), hydrogen (H), and arsenic (As), or a combination of some of the materials.

14. The converter according to claim 13, characterized in that, The magnetothermal material has a form selected from the group consisting of sheets, porous blocks, flakes, pellets, powders, and lumps.

15. The converter according to claim 4, characterized in that, The magnetothermal converter (2) has an annular structure, the stator (S) and the at least one rotor (R, 13, 14) are radially stacked and axially extended, at least a portion of the fluid channel in the actuating element (4) has an axial opening, and the fluid connector (21) is disposed at at least one axial end of the stator (S).

16. The converter according to claim 15, characterized in that, The actuating element (4) is in the form of a rod, extending axially into the stator (S), and each actuating element (4) comprises a porous material block or a material block stacked and defining the fluid channel between material sheets.

17. The converter according to any one of claims 1 to 3, characterized in that, The magnetic poles (5) of the at least one rotor (R, 13, 14) are obtained by magnetic components selected from the group consisting of one or more permanent magnets, ferrites, electromagnets, superconducting magnets, superconducting electromagnets, superconductors, and combinations thereof, and the non-magnetic poles (5') of the at least one rotor (R, 13, 14) are obtained by non-magnetic components.

18. The converter according to any one of claims 1 to 3, characterized in that, The converter includes several magnetocaloric converters (2) connected in series, in parallel, or in a combination of series and parallel.

19. The converter according to any one of claims 1 to 3, characterized in that, The active element (4) comprises a group of magnetothermal materials of different Curie temperatures arranged in ascending or descending order.

20. The converter (1) according to any one of claims 1 to 3, designed to convert electrical energy into heat energy, characterized in that, The converter (1) further includes an actuator connected to at least one rotor (R, 13, 14) of the magnetothermal converter (2, 200) to subject the action element (4) to a variable magnetic field and alternately generate a magnetothermal heating cycle and a magnetothermal cooling cycle in the action element (4). The fluid circuit (6) is connected to the stator (S) on one hand to collect the heat energy generated by the action element (4), and on the other hand to an external device by means of at least one heat exchanger (E1, E2) to transfer the generated heat energy and simultaneously isolate the converter (1) from the at least one external device. The magnetic modulation unit includes the at least one rotor (R, 13, 14) and a synchronization system configured to synchronize the circulation of the heat transfer fluid from the fluid circuit (6) in the action element (4) with the magnetothermal cycle.

21. The converter (1) according to any one of claims 1 to 3, designed to convert thermal energy from a first heat source (S1) at a first temperature (T1) and a second heat source (S2) at a second temperature (T2) different from the first temperature (T1) into electrical energy, characterized in that, The converter (1) further includes an electromechanical converter (3) connected to at least one rotor (R, 13, 14) of the magnetocaloric converter (2, 200) to convert mechanical energy into electrical energy. The fluid circuit (6) is connected to the first heat source (S1) via a first heat exchanger (E1) and to the second heat source (S2) via a second heat exchanger (E2) to collect thermal energy and simultaneously isolate the converter (1) from the heat source. On the other hand, it is connected to the stator (S) to transfer the collected thermal energy to the action element (4). The thermal modulation unit includes a synchronization system configured to subject the action element (4) to temperature changes, generating a permanent magnetic imbalance between the at least one rotor (R, 13, 14) and the stator (S), and causing displacement of the at least one rotor (R, 13, 14) to generate the mechanical energy.

22. The converter according to claim 21, characterized in that, The electromechanical converter (3) is a generator, the rotor (23) of which is directly or by means of a reducer or multiplier (24) connected to at least one rotor (R, 13, 14) of the magnetothermal converter (2) to accommodate the speed of the rotor (R, 13, 14; 23).

23. Use of the converter (1) for converting thermal energy into electrical energy according to claim 21, for recovering waste heat lost in a temperature range from -100°C to +100°C.

24. The use of the converter according to claim 23, wherein, The temperature difference between the first heat source (S1) and the second heat source (S2) is at least 10°C.

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