FR3050517A1 - PROCESS FOR COOLING OR HEATING A FLUID IN A THERMAL ENCLOSURE USING A MAGNETOCALORIC THERMAL GENERATOR AND THERMAL INSTALLATION USING SAID METHOD - Google Patents

Abstract

The invention relates to a thermal installation (10) used for cooling a secondary fluid (FS) by means of a magnetocaloric heat generator (1) connected to a thermal chamber (11) by a heat exchanger (2) in which a heat exchange between a primary fluid (FP) circulating in said generator (1) and the secondary fluid (FS) circulating in said chamber (11) between an injection port (12) where the secondary fluid (FS) enters the thermal enclosure (11) at a first temperature T1, and a suction mouth (13) where the secondary fluid (FS) leaves the thermal chamber (11) at a second temperature T2, different from the first temperature T1. The suction mouth (13) is disposed inside the thermal chamber (11) in a sampling zone (ZP) in which the temperature of the secondary fluid (FS) is the coldest in order to limit the temperature difference between the primary (FP) and secondary (FS) fluids entering said heat exchanger (2).

Description

PROCESS FOR COOLING OR HEATING A FLUID IN A THERMAL ENCLOSURE USING A MAGNETOCALORIATION THERMAL GENERATOR AND THERMAL INSTALLATION USING THE SAME

Technical area :

The present invention relates to a method for cooling or heating a fluid, said secondary fluid, in a thermal chamber by means of a magnetocaloric heat generator connected to said thermal enclosure by at least one heat exchanger in which a heat exchange takes place between a primary fluid circulating in said magnetocaloric heat generator and a secondary fluid circulating in said thermal chamber, the secondary fluid flowing in said thermal chamber between at least one injection port located in the thermal chamber and through which the secondary fluid leaves the the heat exchanger through a secondary outlet to enter the thermal chamber at a first temperature, and at least one suction mouth located in the thermal chamber and through which the secondary fluid out of said thermal chamber to a second temperature, different from the first temper ature, to enter the heat exchanger through a secondary entrance.

The present invention also relates to a thermal installation implementing the method as defined above.

Prior art:

To heat or cool a secondary fluid in a thermal chamber, heat generators are traditionally used, in the form of heat pumps, compressors, or the like, which mainly use a primary phase-change fluid subjected to compression cycles. relaxation. The boiling and condensing temperature of the primary fluid is solely dependent on the working pressure, and totally independent of the ambient temperature or the temperature of the secondary fluid. Thus, the temperatures of the primary fluid of the hot side of the generator (after compression) and the cold side of the generator (after expansion) in this type of application are constant and independent of the temperature of the secondary fluid to be heated or cooled. This property leads to configuring the heat exchanger between the primary circuit and the secondary circuit so as to have the highest possible temperature difference between the inlet temperature of the primary and secondary fluids in said heat exchanger in order to maximize the exchange thermal.

For this reason, when it is desired to cool a secondary fluid in a thermal chamber, the secondary fluid is commonly extracted in the zone of the thermal chamber where the temperature of the secondary fluid is the hottest. Conversely, when it is desired to heat a secondary fluid in a thermal enclosure, the secondary fluid is commonly extracted in the zone of the thermal enclosure where the temperature of the secondary fluid is the coldest.

However, in the case of a magnetocaloric effect heat generator, as illustrated in publications FR 2 861 455 and US Pat. No. 6,453,677, this configuration is not advantageous and even counterproductive.

Indeed, in a magnetocaloric thermal generator, the temperature difference between the primary fluid leaving said generator to enter the heat exchanger and the primary fluid leaving the heat exchanger to enter said generator after exchanging with a secondary fluid in said heat exchanger has a significant impact on the efficiency of said generator and for the following two reasons: 1) At each magnetic cycle, the magnetocaloric material undergoes a temperature variation (adiabatic AT temperature delta) which allows the fluid to cool primary input into said generator on the warm side of the generator and to heat the primary fluid entering the cold side of the generator. If the temperature difference between the incoming primary fluid and the primary fluid leaving said generator is substantially equal to or greater than the magnetocaloric effect of said material (adiabatic ΔΤ), the magnetocaloric heat generator no longer has the capacity to reset the temperature of the fluid. primary exiting at the same level as the previous magnetic cycle, resulting in degradation of the temperature gradient generated by the magnetocaloric heat generator. 2) In addition, the magnetocaloric effect being maximum at the Curie temperature of the magnetocaloric materials, the temperature of the primary fluid leaving the generator is generally equal to the Curie temperature. If the temperature of the primary fluid entering said generator is significantly different from that of the primary fluid leaving said generator, the incoming primary fluid will place the active magnetocaloric material at a temperature away from its Curie temperature thus decreasing the magnetocaloric effect that can generate said material . As a result, the cooling or heating dynamics, intrinsically associated with the magnetocaloric effect, will be slower as the temperature difference between the primary fluid leaving and the primary fluid entering said magnetocaloric heat generator will be high. This phenomenon is particularly noticeable at the start of a thermal installation when a large temperature differential exists between the primary fluid of the magnetocaloric heat generator and the secondary fluid to be cooled or heated contained in a thermal enclosure. This large difference in temperature induces a return temperature of the primary fluid to the magnetocaloric heat generator significantly different from its outlet temperature.

Indeed, the temperature of the primary fluid entering the magnetocaloric heat generator is closely dependent on the temperature of the secondary fluid leaving the thermal chamber and entering the heat exchanger in which it will transfer its calories or frigories to the primary fluid by conduction. Therefore, if it is desired to minimize the temperature difference between the primary fluid entering the generator and the primary fluid leaving the generator, it is imperative to minimize the temperature difference between the secondary fluid leaving the thermal chamber and the secondary fluid entering the thermal chamber, which amounts to limiting the temperature difference between the primary and secondary fluids entering the heat exchanger.

Presentation of the invention

The present invention aims to overcome these drawbacks by proposing a method and a thermal installation using a magnetocaloric heat generator to achieve satisfactory thermal performance to cool or heat the fluid of a thermal chamber, whatever the secondary fluid used in said thermal enclosure and the type of thermal enclosure concerned, minimizing the temperature difference between the secondary fluid leaving the thermal chamber and the secondary fluid entering the thermal chamber to minimize the temperature difference between the fluid primary input into the generator and the primary fluid exiting said generator, thereby reducing the time of establishment of the temperature gradient of said magnetocaloric heat generator at startup and maintain this temperature gradient at an optimum level throughout its operation, said method and said i installation requiring few modifications to achieve this result, simply, efficiently, reliably and cheaply.

For this purpose, the invention relates to a method of the kind indicated in the preamble, characterized in that it identifies a sampling zone inside the thermal chamber in which the temperature of the secondary fluid is coldest when it is desired to cool said secondary fluid, or in which the temperature of the secondary fluid is the hottest when it is desired to heat said secondary fluid, and said at least one suction mouth is positioned in said sampling zone to withdraw said fluid secondary to a second temperature as close as possible to the first temperature of the secondary fluid in order to limit the difference in temperature between the secondary fluid entering the heat exchanger with respect to the secondary fluid leaving said heat exchanger, and consequently limiting the temperature difference between the primary fluid entering the magneto heat generator caloric and the primary fluid exiting said magnetocaloric heat generator.

Thus, the process according to the invention goes against a prejudice according to which, in order to achieve the most optimal thermal exchange possible, preference is given to the largest possible temperature difference between a primary fluid circulating in a heat generator and a fluid. secondary circulating in a thermal chamber, necessarily involving taking the secondary fluid inside the thermal chamber in a sampling zone where the secondary fluid temperature is hottest when you want to cool the secondary fluid, or the most cold when you want to heat the secondary fluid.

At least in a start-up phase of said method, the sampling zone can be identified inside said thermal enclosure by using the natural phenomenon of thermal stratification in which the temperature of the secondary fluid is the coldest in the lower part. the thermal enclosure and the hottest in the upper part of the thermal enclosure.

At least in a development phase of said method, it is possible to identify the sampling zone inside said thermal enclosure by instrumenting said thermal chamber with temperature sensors. In this development phase of said method, it is also possible to determine the position of said at least one injection port and said at least one suction port in the thermal chamber to optimize the circulation of the secondary fluid to the inside said thermal enclosure. It is possible to define said temperature difference of the secondary fluid (FS) between said second temperature and said first temperature so that it is less than or equal to 30% of the magnetocaloric effect of said magnetocaloric heat generator.

According to the embodiment of the invention, it is possible to deviate a part of the incoming flow of the secondary fluid at the first temperature to reinject it at the secondary inlet of said heat exchanger. This part of the deflected flow may be between 5 and 40%, and preferably between 5 and 20%, of the incoming flow of the secondary fluid at the first temperature. The portion of the incoming flow of the secondary fluid can be deflected to the first temperature and fed back to the secondary inlet of said heat exchanger in a direct manner by means of at least one bypass duct extending between the secondary outlet and the secondary outlet. secondary inlet of said heat exchanger. It is also possible to deflect the portion of the incoming flow of the secondary fluid to the first temperature to reinject it at the secondary inlet of said heat exchanger indirectly by means of at least one bypass orifice disposed in the thermal chamber at the first temperature. secondary outlet of said heat exchanger.

For this purpose also, the invention relates to an installation of the kind indicated in the preamble, characterized in that the suction mouth is disposed inside said thermal chamber in a sampling zone in which the temperature of the secondary fluid is the colder when said thermal plant is used to cool a said secondary fluid, or in which the temperature of the secondary fluid is the hottest when said thermal plant is used to heat a said secondary fluid, to withdraw the secondary fluid at a second temperature the as close as possible to the first temperature of the secondary fluid, in order to limit the temperature difference between the secondary fluid entering the heat exchanger and the secondary fluid leaving said heat exchanger, and consequently to limit the difference in temperature between the primary fluid entering into said generator magnetocaloric thermal source and the primary fluid exiting said magnetocaloric heat generator.

When said thermal installation is used to cool a secondary fluid, then said at least one suction mouth is disposed in a lower part of said thermal chamber given the natural phenomenon of thermal stratification.

Conversely, when said thermal installation is used to heat a secondary fluid, said at least one suction mouth is disposed in an upper part of said thermal chamber given the natural phenomenon of thermal stratification.

According to the variant embodiments, the thermal enclosure may comprise at least one bypass duct extending between said secondary outlet and said secondary inlet of said heat exchanger and arranged to directly deflect a portion of the incoming flow of the secondary fluid at the first temperature and reinject it at the secondary inlet of said heat exchanger. The thermal enclosure may alternatively comprise at least one bypass orifice disposed in the thermal enclosure at the secondary outlet of said heat exchanger and arranged to indirectly deflect a portion of the incoming flow of the secondary fluid at the first temperature and reinject it at the inlet secondary of said heat exchanger.

Said at least one bypass duct or said at least one bypass orifice may be arranged to deflect a portion of between 5 and 40%, and preferably between 5 and 20%, of the incoming flow of the secondary fluid at the first temperature.

Brief description of the drawings:

The present invention and its advantages will appear better in the following description of several embodiments given as non-limiting examples, with reference to the appended drawings, in which: FIGS. 1A and 1B are schematic axial sectional views of a first thermal installation according to the invention for an application for cooling a secondary fluid gas in a thermal chamber, using thermal gravity and a direct bypass respectively, and the thermal gravity alone, the heat exchanger being located in the upper part of the 2A, 2B and 2C are diagrammatic axial sectional views of a second thermal installation for an application for heating a secondary fluid gas in a thermal enclosure, respectively using thermal gravity and a bypass direct, thermal gravity and indirect bypass, and thermal gravity Since only the heat exchanger is situated in the upper part of the thermal enclosure to be heated, FIGS. 3A and 3B are schematic axial sectional views of a third thermal installation according to the invention for a heating application of a gaseous secondary fluid in a thermal chamber, respectively using the thermal gravity and a direct bypass, and the thermal gravity alone, the heat exchanger being located in the lower part of the thermal enclosure to be heated, FIGS. 4A, 4B and 4C are schematic axial section views of a fourth thermal installation for a cooling application of a secondary gaseous fluid in a thermal chamber, using thermal gravity and a direct bypass respectively, thermal gravity and indirect bypass, and thermal gravity alone , the heat exchanger being located in the lower part of the thermal enclosure to be cooled, the FIGS. 5A and 5B are diagrammatic axial sectional views of a fifth thermal installation according to the invention for an application for cooling a secondary fluid gas in a thermal enclosure, using thermal gravity and a direct bypass respectively, and thermal gravity alone, the heat exchanger being located on one side of the thermal enclosure to be cooled, Figures 6A and 6B are schematic axial sectional views of a sixth thermal installation according to the invention for a heating application of a gaseous secondary fluid in a thermal chamber, using the thermal gravity and a direct bypass respectively, and the thermal gravity alone, the heat exchanger being located on one side of the thermal chamber to be heated, FIGS. 7A and 7B are schematic axial section views of a seventh thermal installation according to the invention for an applicatio n cooling a liquid secondary fluid in a thermal chamber, using thermal gravity and a direct bypass respectively, and the thermal gravity alone, the heat exchanger being located laterally to the thermal enclosure to be cooled, and FIGS. 8B are views in schematic axial section of an eighth thermal installation according to the invention for an application for heating a secondary fluid gas in a thermal chamber, using thermal gravity and a direct bypass respectively, and the thermal gravity alone, the heat exchanger being located laterally to the heating chamber to be heated.

Illustrations of the invention and different ways of making it:

With reference to the figures, the invention relates to a method and a thermal installation 10-80 for cooling or heating a fluid in a thermal chamber 11-81, called secondary fluid FS. The thermal installation 10-80 according to the invention implements a magnetocaloric thermal generator 1 arranged to produce thermal energy, such as for example that described in the publication WO 2015/079313 A1. This example is of course not limiting. and any other magnetocaloric heat generator 1 may be suitable. This is why the magnetocaloric heat generator 1 will not be described in detail in the present application. Nevertheless, it comprises in known manner at least one thermal stage comprising magnetocaloric materials arranged on a support, a magnetic arrangement arranged to subject said magnetocaloric materials to a magnetic field variation, and at least one coolant circuit, called primary fluid. FP, forced into circulation relative to said magnetocaloric materials to collect the thermal energy they produce when subjected to magnetic cycles. The primary fluid FP is preferably a liquid such as water, mixed or not with one or more additives depending on the applications and the working temperature.

As a reminder, the magnetocaloric effect (EMC) of magnetocaloric materials consists of a variation of their temperature when they are subjected to a magnetic field variation. This magnetocaloric effect therefore depends on the magnetocaloric material and therefore on its Curie temperature, the magnetic field applied to said material and the working temperature of said material. It is thus sufficient to subject these magnetocaloric materials to a succession of magnetic cycles comprising alternating phases. magnetization and demagnetization phases, and to achieve a heat exchange with a heat transfer fluid passing through said materials from one side to achieve the widest possible temperature variation between the hot and cold ends of said materials. The temperature difference between the cold end and the hot end of the magnetocaloric materials, or between the cold side and the hot side of the generator, is commonly referred to as the "temperature gradient" of the magnetocaloric heat generator. The magnetic cycle is repeated up to frequencies of several Hertz. The efficiency of such a cycle of refrigeration or magnetic heating surpasses by about 30% that of a conventional refrigeration or heating cycle. The thermal installation 10-80 according to the invention implements two heat exchangers 2, 3, one connected to the cold side and the other connected to the hot side of the magnetocaloric heat generator 1. Depending on the application considered, one of the heat exchangers 2 is a cold or hot exchanger connecting the cold or hot side of the magnetocaloric heat generator 1 to the thermal enclosure 11-81 to cool or heat it, and the other heat exchanger 3 is a hot or cold heat exchanger connecting the Another hot or cold side of the magnetocaloric heat generator 1 to the atmosphere or other environment. These heat exchangers 2, 3 allow a thermal exchange between a primary fluid FP on the one hand flowing in the magnetocaloric heat generator 1, and a secondary fluid FS on the other hand flowing in the thermal chamber 11-81 to heat or cool the interior volume of said enclosure or to exchange with the atmosphere. The heat exchanger 2, 3 can be a liquid / liquid exchanger when the two fluids FP, FS in the presence are liquids or a liquid / gas exchanger when the primary fluid FP is a liquid and the secondary fluid FS is a gaseous medium. This type of heat exchanger 2, 3 is well known and will not be described in detail in the present application. However, they each comprise at least one primary circuit CP in which the primary fluid FP flows between at least one primary input EP and one primary output SP, a secondary circuit CS in which the secondary fluid FS flows between at least one secondary input ES and a secondary output SS, and a heat exchange zone between the two fluids FP, FS in which they generally circulate in opposite direction, said countercurrent, for the liquid / liquid exchangers, or in cross flows for the liquid / liquid exchangers air, this heat exchange zone may be plates, tubular, tube and shell, coil, fin or a combination of these means. The two primary fluids FP and secondary FS are preferably circulated forcibly inside the heat exchanger 2, 3. The primary fluid FP can be forced to circulation in the primary circuit CP of the heat exchanger 2. via a pump (not shown) disposed in the magnetocaloric heat generator 1, or any other device allowing the movement of the primary fluid such as pistons, membranes or the like. And the secondary fluid FS can be forced into the secondary circuit CS of the heat exchanger 2, 3 by any suitable drive means, such as a fan 4 when the secondary fluid is a gaseous medium, a pump 5 when the secondary fluid is a liquid.

In the thermal system 10-80 of the invention, the thermal enclosure 11-81 contains a secondary fluid FS in a volume that can be sealed or not, open totally or partially, depending on the purpose of the thermal enclosure 11 -81 and the nature of the secondary fluid FS. The secondary fluid FS is intended to be cooled or heated, depending on whether it is a cooling or heating application. This secondary fluid FS may be different depending on the application considered. Π may consist of a gaseous medium, such as for example air, when the thermal enclosure 11-61 is a living room, a vehicle, a pushing chamber, a cold room such as a refrigerator, a refrigerated cabinet, a food distributor, a wine cellar, etc. or any other gas used in an industrial process, for example in the case of a storage application in a tank at a temperature different from the ambient temperature. It may also consist of a liquid, such as water when the thermal enclosure 71-81 is a water heater, a tank or a tank of liquid food such as milk, beer, etc. It may finally consist of a completely different fluid used in an industrial process for example, requiring a storage temperature different from the ambient temperature, such as liquid nitrogen, oil, etc. when the thermal enclosure is a tank. These examples of secondary fluids FS and thermal chambers 11-81 are given for information only and are not limiting.

In addition, the secondary fluid FS contained in the thermal chamber 11-81 naturally organizes itself in vertically superposed layers according to its temperature ranging between a lower layer in which its lowest temperature is located in the lower part of the chamber. the thermal enclosure 11-81 and an upper layer in which its temperature is the highest located in the upper part of the thermal chamber 11-81. This natural phenomenon is due to the density of a fluid which varies with its temperature and which generates a thermal stratification corresponding to a vertical distribution of the temperature in a fluid, implying because of the gravity that the hot fluid is found elsewhere. above the cold fluid. The method and thermal installation 10-80 according to the invention will exploit at least in part this natural phenomenon. Nevertheless, there are complex thermal chambers (not shown) in which the thermal stratification is not applicable since these thermal enclosures comprise internal brewing or ventilation means and / or obstacles in the useful volume such as drawers, shelves , or the charges themselves, etc. The method and the thermal installation according to the invention remain however applicable in these complex installations as explained below.

With reference more particularly to FIGS. 1A and 1B, the thermal installation 10 according to the invention is intended for a cooling application. It comprises for this purpose a closed thermal enclosure 11 containing a secondary fluid FS to be cooled, which in this example is a gas mixture such as air. In this embodiment, the magnetocaloric heat generator 1 and the heat exchanger 2 are arranged in the upper part of the thermal enclosure 11. The heat exchanger 2 is a liquid / gas exchanger and is located inside the heat exchanger. thermal enclosure 11 while the magnetocaloric generator 1 is disposed outside the thermal enclosure 11. Of course, any other configuration may be suitable, in which the magnetocaloric generator 1 and the heat exchanger 2 are both arranged at the outside or inside the thermal enclosure 11. The fluidic connections provided respectively between the magnetocaloric heat generator 1 and the heat exchanger 2, and between the heat exchanger 2 and the thermal enclosure 11 are carried out either by pipes and fittings, either by direct connections without pipe depending on the configuration of the thermal installation 10.

The primary circuit CP, in which the primary fluid FP is circulated, is represented in the form of a fluid loop which leaves the magnetocaloric heat generator 1, to enter the heat exchanger 2 via a primary inlet EP, then into is output by a primary output SP to return to the magnetocaloric heat generator 1. The secondary circuit CS, in which the secondary fluid FS is circulated by a fan 4, is represented in the form of a fluidic loop, illustrated by FIG. arrows, which leaves the heat exchanger 2 by a secondary outlet SS, to return to a first temperature Tl in the thermal chamber 11 by an injection port 12, then leaves at a second temperature T2 by a mouth of suction 13 to enter the heat exchanger 2 again via a secondary inlet ES. For this cooling application, the first temperature T1 is necessarily lower than the second temperature T2. The thermal enclosure 11 has internal walls 14 arranged to delimit the useful volume of the thermal enclosure 11 relative to the secondary circuit CS. The inner walls 14 have for this purpose openings for placing this useful volume in communication with the secondary circuit CS, namely the injection port 12 in the thermal chamber 11 and the secondary outlet SS of the heat exchanger 2 which are in this example combined and located in the upper part of the thermal chamber 11, and the suction mouth 13 located in the lower part of the thermal chamber 11 and the secondary inlet ES of the heat exchanger 2 located in the upper part of the thermal enclosure 11 which are in this example connected by a suction pipe 15 substantially vertical delimited by a portion of the inner walls 14.

In the embodiment of FIG. 1A, the thermal enclosure 11 further comprises a branch duct 16 situated at the top of the thermal enclosure 11, delimited by another part of the internal walls 14, extending substantially horizontally between the secondary output SS and the secondary input ES of the heat exchanger 2 to deflect part of the incoming flow of the secondary fluid FS to reinject it directly into the heat exchanger 2. The section of the bypass duct 16 is defined to deflect a portion of the incoming flow of the secondary fluid FS of the order of 5 to 40% and preferably 5 to 20%. These values are given for information only and are not limiting. In the example of FIG. 1B, the thermal enclosure 11 has no bypass duct 16.

The operation of the thermal installation 10 according to FIGS. 1A and 1B consists in cooling the secondary fluid FS contained in the thermal enclosure 11 by circulating it through the heat exchanger 2 so that it exchanges thermally with the primary fluid FP circulating in the magnetocaloric heat generator 1, between the secondary inlet ES through which it enters the heat exchanger 2 at a second temperature T2, and the secondary outlet SS through which it leaves the heat exchanger 2 after have been cooled to a first temperature T1, lower than the second temperature T2. To optimize this heat exchange and to accelerate the cooling of the secondary fluid FS, natural thermal stratification is used and the secondary fluid FS contained in the thermal chamber 11 is sampled in a sampling zone ZP where the temperature of the secondary fluid FS is the colder, at a second temperature T2 higher but close to the first temperature T1, according to Figure IB, and in contrast to the state of the art methods. This sampling zone ZP is in this example located in the lower part of the thermal enclosure 11 in which is positioned the suction mouth 13 which communicates with the secondary inlet ES of the heat exchanger 2 by the suction duct 15. It is also possible to use the natural thermal stratification combined with a bypass of a part of the incoming flow, making it possible to reinject into the secondary inlet ES of the heat exchanger 2, a secondary fluid mixture at the first temperature T 1 by the bypass duct 16 and the second temperature T2 by the suction port 13, according to Figure IA.

In this cooling application, the interest of taking the secondary fluid FS has a second temperature T2 as cold as possible in the thermal chamber 11 and therefore as close as possible to the first temperature T1 to which it is injected into said thermal chamber 11, lies in limiting the temperature difference between the secondary fluid FS entering the heat exchanger 2 at the second temperature T2 and the secondary fluid FS leaving said heat exchanger at the first temperature Tl, and consequently to limit the temperature difference between the primary fluid FP entering the magnetocaloric heat generator 1 and the primary fluid FP exiting said generator. For example, it is sought to ensure that the temperature difference between the secondary fluid FS entering the heat exchanger 2 relative to the secondary fluid leaving said heat exchanger jmi is less than or equal to about 30% of the magnetocaloric effect of the magnetocaloric heat generator 1, which makes, by way of example, for a magnetocaloric effect of 2.5K a maximum temperature difference of 0.75K at the level of the secondary fluid FS. As a result, a temperature difference is obtained between the primary fluid FP entering the magnetocaloric heat generator 1 with respect to the primary fluid FP coming out of said magnetocaloric heat generator of the order of 30 to 60% of the magnetocaloric effect of the magnetocaloric heat generator. 1, which makes, by way of example, for a magnetocaloric effect of 2.5K a maximum temperature difference of 0.75 K to 1.5K between the two fluids FP and FS entering said heat exchanger 2. Thus, the primary fluid FP which enters the magnetocaloric heat generator 1, after having exchanged with the secondary fluid FS in said heat exchanger 2, has a temperature difference with the primary fluid FP coming from said thermal generator lower than a value of about 30 at 60% of the magnetocaloric effect and a temperature remaining close to the Curie temperature of the material at the temperature of The coldest curie so that the magnetocaloric heat generator 1 has the capacity to return this primary fluid FP, emerging in the next half cycle, at the same temperature as the previous cycle. As a result, the magnetocaloric materials can thus work at their optimum Curie temperature, making it possible to preserve the temperature gradient of the magnetocaloric heat generator 1 and to accelerate the cooling of the secondary fluid FS. The advantage of this method is all the more important in the starting phase of the thermal installation 10 when the secondary fluid FS contained in the thermal chamber 11 may be at an initial temperature T2 much greater than its temperature T2 in steady state .

In FIGS. 2A, 2B and 2C, the thermal installation 20 according to the invention is intended for a heating application and comprises a closed thermal enclosure 21 containing a secondary fluid FS to be heated, which is, as in the previous example, a mixture gas such as air. Parts and components identical to the previous example have the same reference number. The positioning of the magnetocaloric heat generator 1 and the heat exchangers 2, 3 with respect to the thermal enclosure 21 is identical to the thermal installation 10 of FIGS. 1A and 1B. The thermal enclosure 21 has internal walls 24 which delimit the useful volume of the thermal enclosure 21 relative to the secondary circuit CS. The inner walls 24 have for this purpose openings for communicating this useful volume with the secondary circuit CS, namely several injection ports 22 located at different levels in the thermal chamber 21 and the secondary outlet SS of the exchanger thermal 2 located in the upper part of the thermal chamber 21 which are in this example connected by a substantially vertical injection conduit 27 defined by a portion of the inner walls 24, and a suction mouth 23 and the secondary entrance ES of the heat exchanger 2 located in the upper part of the thermal enclosure 11 which are in this example combined.

In the embodiment of FIG. 2A, the thermal enclosure 21 further comprises a branch duct 26 situated at the top of the thermal enclosure 21, delimited by another part of the internal walls 24, extending substantially horizontally between the secondary output SS and the secondary input ES of the heat exchanger 2 to deflect part of the incoming flow of the secondary fluid FS to reinject it directly into the heat exchanger 2. As before, the section of the bypass duct 26 is defined according to the percentage of the secondary fluid FS to be deflected. In the example of FIG. 2B, the thermal enclosure 21 comprises not a bypass duct 26 but at least one bypass orifice 28 located at the secondary outlet SS of the heat exchanger 2 and associated with a deflector 29 for diverting a part of the incoming flow of the secondary fluid FS so that it is sucked and reinjected indirectly in the heat exchanger 2. In the example of Figure 2C, the thermal enclosure 21 does not include bypass conduit 26, or d bypass port 28.

The operation of the thermal installation 20 according to FIGS. 2A to 2C consists in heating the secondary fluid FS contained in the thermal enclosure 21 by circulating it through the heat exchanger 2 so that it exchanges thermally with the primary fluid FP circulating in the magnetocaloric heat generator 1, between the secondary inlet ES through which it enters the heat exchanger 2 at a second temperature T2, and the secondary outlet SS through which it leaves the heat exchanger 2 after have been heated to a first temperature T1, higher than the second temperature T2. To optimize this heat exchange and to accelerate the heating of the secondary fluid FS, natural thermal stratification is used and the secondary fluid FS contained in the thermal chamber 21 is sampled in a sampling zone ZP where the temperature of the secondary fluid FS is the more hot at a second temperature T2 lower but close to the first temperature Tl, according to Figure 2B, and in contrast to the methods of the state of the art. This sampling zone ZP is in this example located in the upper part of the thermal enclosure 21 in which is positioned the suction mouth 23 which communicates with the secondary inlet ES of the heat exchanger 2. It can also be used. natural thermal stratification combined with a direct or indirect derivation of a part of the incoming flow, for injecting into the secondary inlet ES of the heat exchanger 2, a mixture of secondary fluid at the first temperature T1 through the bypass duct 26 or the bypass orifice 28 and the second temperature T2 by the suction mouth 23, in accordance with Figures 2A and 2B, respectively.

In this heating application, the objective is the same as that mentioned above, namely to limit the temperature difference between the secondary fluid FS entering the heat exchanger 2 at the second temperature T2 and the secondary fluid FS leaving said heat exchanger at the first temperature T1, and consequently to limit the temperature difference between the primary fluid FP entering the magnetocaloric heat generator 1 and the primary fluid FP coming out of said generator, to preserve the temperature gradient of the magnetocaloric heat generator. 1 and accelerate the heating of the secondary fluid FS.

The other examples of thermal installation 30-80, with reference to FIGS. 3 to 8, have different configurations but use the same method making it possible to optimize the thermal variation of a secondary fluid FS in a thermal enclosure 31-81, which it is a gaseous mixture or a liquid, by means of a magnetocaloric heat generator 1. The operation of these various thermal systems 30-80 will therefore not be re-explained. Parts and components identical to the preceding examples bear the same reference number.

In FIGS. 3A and 3B, the thermal installation 30 according to the invention is intended for a heating application. In this example, the magnetocaloric heat generator 1 and the heat exchangers 2, 3 are arranged in the lower part of the thermal enclosure 31, one of the heat exchangers 2 being located inside the thermal enclosure 31 and the magnetocaloric generator 1 and the other heat exchanger 3 being located outside. The thermal enclosure 31 has internal walls 34 provided with openings to put its useful volume in communication with the secondary circuit CS, namely an injection port 32 and the secondary outlet SS of the heat exchanger 2 located at the bottom of the thermal enclosure 31 which are in this example combined, and a suction mouth 33 located in the upper part of the thermal chamber 31, in a sampling zone ZP where the temperature of the secondary fluid is the hottest, and the secondary inlet ES of the heat exchanger 2 located in the lower part of the thermal enclosure 11, which are in this example connected a substantially vertical suction duct 35 delimited by a part of the inner walls 34.

In the embodiment of FIG. 3A, the thermal enclosure 31 further comprises a bypass duct 36 located in the lower part of the thermal enclosure 31 delimited by another part of the internal walls 34 extending substantially horizontally between the secondary output SS and the secondary input ES of the heat exchanger 2 in order to deflect part of the inflow of the secondary fluid FS to the first temperature Tl to reinject it directly into the heat exchanger 2 mixed with the flow out of the secondary fluid FS at the second temperature T2. In the example of FIG. 3B, the thermal enclosure 31 has no bypass duct 36 and uses only the thermal stratification that makes it possible to inject into the heat exchanger 2 the flow exiting the secondary fluid FS at the second temperature T2. close to the first temperature T1 of the incoming flow.

In FIGS. 4A, 4B and 4C, the thermal installation 40 according to the invention is intended for a cooling application. The positioning of the magnetocaloric heat generator 1 and the heat exchangers 2, 3 with respect to the thermal enclosure 41 is identical to the thermal installation 30 of FIGS. 3A and 3B. The thermal enclosure 41 has inner walls 44 provided with openings for communicating its useful volume with the secondary circuit CS, namely several injection ports 42 located at different levels in the thermal chamber 41 and the secondary outlet SS the heat exchanger 2 located in the lower part of the thermal chamber 41 which are in this example connected by a substantially vertical injection conduit 47 delimited by a portion of the inner walls 44, and a suction mouth 43 and the secondary inlet ES of the heat exchanger 2 combined and located in the lower part of the thermal enclosure 41, in a sampling zone ZP where the temperature of the secondary fluid is the coldest.

In the embodiment of FIG. 4A, the thermal enclosure 41 further comprises a bypass duct 46 situated in the lower part of the thermal enclosure 41, delimited by another part of the interior walls 44, extending substantially horizontally between the secondary output SS and the secondary input ES of the heat exchanger 2 to deflect part of the incoming flow of the secondary fluid FS to the first temperature Tl to reinject it directly into the heat exchanger 2, mixed with the outgoing flow secondary fluid FS at the second temperature T2. In the example of FIG. 4B, the thermal enclosure 41 comprises not a bypass duct 46 but at least one bypass orifice 48 located at the secondary outlet SS of the heat exchanger 2 and associated with a deflector 49 to divert a part of the incoming flow of the secondary fluid FS at the first temperature T1, so that it is sucked and reinjected indirectly into the heat exchanger 2, mixed with the flow leaving the secondary fluid FS at the second temperature T2. In the example of FIG. 4C, the thermal enclosure 41 has no bypass duct 46 or bypass orifice 48, and uses only the thermal stratification for injecting into the heat exchanger 2 the outgoing flow. secondary fluid FS at the second temperature T2 close to the first temperature T1 of the incoming flow.

FIGS. 5A, 5B and 6A, 6B illustrate thermal installations 50 and 60 in which the magnetocaloric heat generator 1 and the heat exchangers 2, 3 are arranged laterally on one side of the thermal enclosure 51, 61, one of the heat exchangers 2 being located inside the thermal chamber 51, 61, and the other heat exchanger 3 with the magnetocaloric heat generator 1 being located outside. The thermal plant 50 of Figures 5A and 5B is for a cooling application. The thermal chamber 51 has internal walls 54 provided with openings for communicating its useful volume with the secondary circuit CS, namely an injection port 52 situated in the upper part of the thermal enclosure 51 and the secondary outlet SS of the heat exchanger 2 located in the middle part which are in this example connected by an injection conduit 57, and a suction mouth 53 located in the lower part of the thermal enclosure 51, in a sampling zone ZP where the temperature of the secondary fluid is the coldest, and the secondary inlet ES of the heat exchanger 2 located in the middle part which are in this example connected to a suction duct 55. The injection lines 57 and suction 55 are substantially vertical, in the extension of one another and delimited by a portion of the inner walls 54.

In the embodiment of FIG. 5A, the thermal enclosure 51 further comprises a bypass duct 56 located in the middle part of the thermal enclosure 51, delimited by another part of the inner walls 54, extending substantially vertically between the secondary output SS and the secondary input ES of the heat exchanger 2 in order to deflect part of the incoming flow of the secondary fluid FS to the first temperature T1 to reinject it directly into the heat exchanger 2, mixed with the outgoing flow secondary fluid FS at the second temperature T2. In the example of FIG. 5B, the thermal enclosure 51 has no bypass duct 56 and uses only the thermal stratification for injecting into the heat exchanger 2 the flow leaving the secondary fluid FS at the second temperature T2 close to the first temperature T1 of the incoming flow. The thermal plant 60 of Figures 6A and 6B is for a heating application. The thermal chamber 61 has internal walls 64 provided with openings for communicating its useful volume with the secondary circuit CS, namely an injection port 62 situated in the lower part of the thermal chamber 61 and the secondary outlet SS of the heat exchanger 2 located in the middle part which are in this example connected by an injection conduit 67, and a suction mouth 63 located in the upper part of the thermal chamber 61, in a sampling zone ZP where the temperature of the secondary fluid is the hottest, and the secondary inlet ES of the heat exchanger 2 located in the middle part which are in this example connected to a suction duct 65. The injection lines 67 and suction 65 are substantially vertical, in the extension of one another and delimited by a part of the inner walls 64.

In the exemplary embodiment of FIG. 6A, the thermal enclosure 61 further comprises a bypass duct 66, located in the middle part of the thermal enclosure 61, delimited by another part of the internal walls 64, extending substantially vertically between the secondary output SS and the secondary input ES of the heat exchanger 2 in order to deflect part of the incoming flow of the secondary fluid FS to the first temperature T1 to reinject it directly into the heat exchanger 2, mixed with the outgoing flow secondary fluid FS at the second temperature T2. In the example of FIG. 6B, the thermal enclosure 61 has no bypass duct 66 and uses only the thermal stratification for injecting into the heat exchanger 2 the flow leaving the secondary fluid FS at the second temperature T2 close to the first temperature T1 of the incoming flow.

FIGS. 7A, 7B and 8A, 8B illustrate thermal installations 70 and 80 in which the thermal enclosure 71, 81 is hermetically sealed and contains a secondary fluid FS in the form of a liquid to be cooled in the thermal installation 70 of the FIGS. 7A, 7B or to be heated in the thermal installation 80 of FIGS. 8A, 8B. The magnetocaloric heat generator 1 and the heat exchangers 2, 3 are, in these examples, arranged laterally outside the thermal enclosure 71, 81. The heat exchanger 2 communicating with the thermal chamber 71, 81 is this time a liquid / liquid exchanger, the secondary circuit CS comprises a pump 5 circulating the secondary fluid FS through ducts 6 opening into the thermal chamber 71,81 through an injection port 72, 82 and a mouth suction 73, 83.

With reference to FIGS. 7A and 7B, and as in the previous examples, to optimize the heat exchange within the heat exchanger 2 between the primary fluid FP and the secondary fluid FS and to accelerate the cooling of the secondary fluid FS, it is possible to use only the natural thermal stratification and the secondary fluid FS contained in the thermal chamber 71 will be taken from a sampling zone ZP where the temperature of the secondary fluid FS is the coldest to inject it into the secondary inlet ES of the heat exchanger 2 at a second temperature T2 higher but close to the first temperature T1, in accordance with Figure 7B, and in contrast to the state of the art methods. This sampling zone ZP is, in this cooling application, located in the lower part of the thermal enclosure 71 in which is positioned the suction port 73 which communicates with the secondary inlet ES of the heat exchanger 2. In this example, the injection port 72, which communicates with the secondary outlet SS of the heat exchanger 2, is located in the upper part of the thermal chamber 71, from which the secondary fluid FS leaves the heat exchanger 2 at the first temperature T1 lower than the second temperature T2. The incoming flow of the secondary fluid FS then moves naturally inside the thermal enclosure 71 from top to bottom. It is also possible to use the natural thermal stratification combined with a direct bypass of a part of the incoming flow, making it possible to reinject into the secondary inlet ES of the heat exchanger 2 a mixture of secondary fluid FS at the first temperature T 1 by a bypass line 76 and at the second temperature T2 by the suction port 73. In this case and according to FIG. 7A, the bypass duct 76 is outside the thermal enclosure 81 and extends between the secondary outlet SS and the secondary inlet ES of the heat exchanger 2, and its section is defined according to the percentage of the secondary fluid FS to be deflected.

Similarly, and with reference to FIGS. 8A and 8B, to optimize the heat exchange within the heat exchanger 2 between the primary fluid FP and the secondary fluid FS and to accelerate the heating of the secondary fluid FS, it is possible to use only the natural thermal stratification and we will take the secondary fluid FS contained in the thermal chamber 71 in a sampling zone ZP where the secondary fluid temperature FS is the hottest to inject it into the secondary inlet ES of the heat exchanger 2 at a second temperature T2 lower but close to the first temperature Tl, according to Figure 8B, and in contrast to the methods of the state of the art. This sampling zone ZP is, in this cooling application, located in the upper part of the thermal chamber 81 in which is positioned the suction mouth 83 which communicates with the secondary inlet ES of the heat exchanger 2. In this example, the injection port 82, which communicates with the secondary outlet SS of the heat exchanger 2, is located in the lower part of the thermal chamber 81, from which the secondary fluid FS leaves the heat exchanger 2 at the first temperature Tl greater than the second temperature T2. Fe incoming flow of the secondary fluid FS then moves naturally inside the thermal enclosure 71 from bottom to top. It is also possible to use the natural thermal stratification combined with a direct bypass of a part of the incoming flow, making it possible to reinject into the secondary inlet ES of the heat exchanger 2 a mixture of secondary fluid FS at the first temperature T 1 by a bypass duct 86 and at the second temperature T2 through the suction port 83. In this case and according to FIG. 8A, the bypass duct 86 is outside the thermal enclosure 81 and extends between the secondary outlet SS and the secondary inlet ES of the heat exchanger 2, and its section is defined according to the percentage of the secondary fluid FS to be deflected.

In the non-illustrated case of complex thermal enclosures where the thermal stratification can not be exploited, the ZP sampling zone is identified inside the thermal enclosure by instrumenting the thermal chamber with temperature sensors in one phase. process development. In this development phase, it is also possible to determine the position of the injection port and the suction mouth in the thermal chamber to optimize the circulation of the secondary fluid inside the thermal chamber.

The examples of embodiment detailed above are not exhaustive, but allow to illustrate the different cases that can be encountered in heating or cooling applications, and in which it is possible to always apply the same process for modifying the temperature of a secondary fluid FS in a thermal chamber 11-81 by maximizing the performance of a magnetocaloric heat generator 1.

The present invention is not limited to the embodiments described but extends to any modification and variation obvious to a person skilled in the art.

Claims (17)

claims 1. Method for cooling or heating a fluid, said secondary fluid, in a thermal chamber (11-81) by means of a magnetocaloric heat generator (1) connected to said thermal chamber (11-81) by at least one heat exchanger (2) wherein a heat exchange occurs between a primary fluid (PF) flowing in said magnetocaloric heat generator (1) and a secondary fluid (FS) circulating in said thermal chamber (11-81), the secondary fluid (FS). circulating in the thermal chamber (11-81) between at least one injection port (12-82) located in the thermal chamber (11-81) and through which the secondary fluid (FS) exits the heat exchanger (2) through a secondary outlet (SS) to enter the thermal chamber (11-81) at a first temperature T1, and at least one suction mouth (13-83) located in the thermal chamber (11-81) and through which the secondary fluid (FS) exits said thermal enclosure (11-81) at a second temperature T2 different from the first temperature T1 to enter the heat exchanger (2) by a secondary inlet (ES), said method being characterized in that a zone of sampling (ZP) inside said thermal chamber (11-81) in which the temperature of the secondary fluid (FS) is coldest when it is desired to cool said secondary fluid (FS), or in which the fluid temperature secondary (FS) is the hottest when one wishes to heat said secondary fluid (FS), and one positions said at least one suction mouth (13-83) in said sampling zone (ZP) to collect said fluid secondary (FS) at a second temperature T2 as close as possible to the first temperature Tl of the secondary fluid (FS) in order to limit the temperature difference between the secondary fluid (FS) entering the heat exchanger (2) by means of rt to the secondary fluid (FS) leaving said heat exchanger, and consequently to limit the temperature difference between the primary fluid (FP) entering in said magnetocaloric heat generator (1) and the primary fluid (FP) leaving said generator thermal magnetocaloric. 2. Method according to claim 1, characterized in that said sampling zone (ZP) is identified inside said thermal chamber (11-81) using the natural phenomenon of thermal stratification in which the temperature of the fluid secondary (FS) is the coldest in the lower part of the thermal enclosure (11-81) and the hottest in the upper part of the thermal enclosure (11-81), at least in a starting phase of said process . 3. Method according to claim 1, characterized in that said sampling zone (ZP) is identified inside said thermal chamber (11-81) by instrumenting said thermal chamber (11-81) with sensors of temperature at least in a development phase of said process. 4. Method according to claim 3, characterized in that, in said development phase of said method, also determines the position of said at least one injection port (12-82) and said at least one mouth of suction (13-83) in said thermal chamber (11-81) for optimizing the circulation of the secondary fluid (FS) inside said thermal chamber (11-81). 5. Method according to any one of the preceding claims, characterized in that said temperature difference of the secondary fluid (FS) is defined between the second temperature T2 and the first temperature T1 to be less than or equal to 30. % of the magnetocaloric effect of said magnetocaloric heat generator (1). 6. Method according to any one of the preceding claims, characterized in that one deflects a portion of the incoming flow of the secondary fluid (FS) to the first temperature T1 to reinject it to the secondary inlet (ES) of said heat exchanger (2). 7. The method of claim 6, characterized in that the portion of the deflected flow is between 5 and 40% of the incoming flow of the secondary fluid (FS) at the first temperature Tl. 8. The method of claim 7, characterized in that the portion of the deflected flow is preferably between 5 and 20% of the incoming flow of the secondary fluid (FS) at the first temperature Tl. 9. Method according to any one of claims 6 to 8, characterized in that Ton deviates said portion of the incoming flow of the secondary fluid (FS) to the first temperature T1 to reinject it to the secondary inlet (ES) of said heat exchanger (2). ) directly by means of at least one bypass duct (16-86) extending between the secondary outlet (SS) and the secondary inlet (ES) of said heat exchanger (2). 10. A method according to any one of claims 6 to 8, characterized in that Ton deviates said portion of the incoming flow of the secondary fluid (FS) to the first temperature T1 to reinject it to the secondary inlet (ES) of said heat exchanger (2). ) indirectly by means of at least one bypass orifice (28, 48) disposed in the thermal chamber (21, 41) at the secondary outlet (SS) of said heat exchanger (2). 11. Thermal plant (10-80) implementing the method according to any preceding claim for cooling or heating a fluid said secondary fluid in a thermal chamber (11-81), said thermal installation (10-80) comprising at least a magnetocaloric heat generator (1) connected to said thermal enclosure (11-81) by at least one heat exchanger (2) in which a heat exchange takes place between a primary fluid (FP) flowing in said magnetocaloric heat generator (1) and a secondary fluid (FS) flowing in said thermal chamber (11-81), the secondary fluid (FS) flowing in the thermal chamber (11-81) between at least one injection port (12-82) located in the thermal enclosure (11-81) and through which the secondary fluid (FS) leaves the heat exchanger (2) through a secondary outlet (SS) to enter the thermal chamber (11-81) at a first temperature Tl, and u a suction mouth (13-83) located in the thermal chamber (11-81) and through which the secondary fluid (FS) leaves said thermal chamber (11-81) at a second temperature T2 different from the first temperature T1 to enter the heat exchanger (2) through a secondary inlet (ES), said thermal installation being characterized in that said suction mouth (13-83) is disposed inside said thermal enclosure ( 11-81) in a sampling zone (ZP) in which the temperature of the secondary fluid (FS) is the coldest when said thermal installation is used for cooling said secondary fluid (FS), or in which the temperature of the secondary fluid ( FS) is the hottest when said thermal plant is used to heat said secondary fluid (FS), to withdraw the secondary fluid (FS) at a second temperature T2 as close as possible to the first temperature rature T1 of the secondary fluid (FS), in order to limit the temperature difference between the secondary fluid (FS) entering the heat exchanger (2) relative to the secondary fluid leaving said heat exchanger, and consequently to limit the temperature difference between the primary fluid (FP) entering said magnetocaloric heat generator (1) relative to the primary fluid (FP) leaving said magnetocaloric heat generator. 12. Installation according to claim 11, characterized in that, when said thermal installation is used to cool a secondary fluid (FS), said at least one suction mouth (13, 43, 53, 73) is arranged in a part of said thermal enclosure (11, 43, 53, 73) taking into account the natural phenomenon of thermal stratification. 13. Installation according to claim 11, characterized in that, when said thermal installation is used to heat a secondary fluid (FS), said at least one suction mouth (23, 33, 63, 83) is arranged in a part high of said thermal enclosure (21, 31, 61, 81) taking into account the natural phenomenon of thermal stratification. 14. Installation according to any one of claims 11 to 13, characterized in that said thermal enclosure (11-81) comprises at least one bypass duct (16-86) extending between said secondary outlet (SS) and said secondary inlet (ES) of said heat exchanger (2) and arranged to directly deflect a portion of the incoming flow of the secondary fluid (FS) to the first temperature T1 and reinject it to the secondary inlet (ES) of said heat exchanger (2). 15. Installation according to any one of claims 11 to 13, characterized in that said thermal enclosure (21, 41) comprises at least one bypass orifice (28, 48) disposed in the thermal chamber (21, 41) to the secondary output (SS) of said heat exchanger (2) and arranged to indirectly deflect a portion of the incoming flow of the secondary fluid (FS) to the first temperature T1 and reinject it to the secondary inlet (ES) of said heat exchanger (2) . 16. Installation according to any one of claims 14 and 15, characterized in that said at least one bypass duct (16-86) or said at least one bypass orifice (28, 48) is arranged to deflect a part included between 5 and 40% of the incoming flow of the secondary fluid (FS) at the first temperature T1. 17. Installation according to claim 16, characterized in that said at least one bypass duct (16-86) or said at least one bypass orifice (28, 48) is arranged to deflect a portion preferably between 5 and 20 % of the incoming flow of the secondary fluid (FS) at the first temperature T1.