FR3109986A1 - COOLING SYSTEM, AIR CONDITIONING SYSTEM, ENGINE ASSEMBLY AND ASSOCIATED PROCESSES - Google Patents

Abstract

- Cooling system, air conditioning system, engine assembly and associated methods - The invention relates to a cooling system (1) comprising at least:- a Stirling heat pump (2) adapted to cool an inlet gas (Ge) down to a cryogenic temperature in order to form a cryogenic liquid (L),- a primary electric motor (3), intended to operate the said Stirling heat pump (2),- a primary pump (4) intended to circulate the said cryogenic liquid (L) under pressure, and- cooling means (5), intended to cool said primary electric motor (3) using cryogenic liquid (L) from said primary pump (4). - The invention is particularly suitable for the production of a cryogenic liquid and its applications. - Figure for the abstract: Figure 1.

Description

COOLING SYSTEM, AIR CONDITIONING SYSTEM, ENGINE ASSEMBLY AND ASSOCIATED PROCESSES

The present invention relates to the general field of the cooling of an initially gaseous component until liquefaction, more precisely at a very low temperature and in particular cryogenic.

The invention thus relates to a cooling system.

The invention further relates to an air conditioning system, an engine assembly, an adaptation method, a cooling method and an associated oxycombustion method.

Traditionally, the regulated use, transport or storage of a gaseous component requires carrying out an operation to concentrate this gaseous component, for example by means of a compressor. The concentration operation can also be carried out by liquefaction of the initially gaseous component.

To achieve the liquefaction of a gaseous component, it is thus known to implement cooling systems and compression systems.

These systems dedicated to the liquefaction of a gas, although generally satisfactory in their use, nevertheless have certain drawbacks.

Thus, the known cooling systems dedicated to the liquefaction of a gas have a high energy cost, a mediocre efficiency at best, a complex implementation and a consequent dimensioning with regard to the relatively low quantity of liquefied gas produced per unit of time.

Known compression systems, in particular those dedicated to the liquefaction of a gas, also have a high energy cost, especially since they also have significant heat losses due to the very fact of the compression of the gas and the inherent friction. to the movement of their compression member, for example a piston in the case of a piston compressor. Such a configuration limits in practice the compression ratio of each stage, in particular when it is necessary to reach high pressures. Compressors may therefore need to be cooled at each of their stages, which consumes even more energy. Finally, the known compression systems present significant safety risks linked to the storage of compressed gas, and are generally not suitable, alone, for the liquefaction of certain gases, in particular for the liquefaction of the gaseous components of air.

Thus, even if gas liquefaction systems are known and feasible as such, the drawbacks mentioned above demonstrate that they are not suitable for a simple, efficient and safe implementation of the concentration of a gas and all the more so the liquefaction of a gas.

Ultimately, known gas liquefaction systems, in particular of the cooling or compression liquefaction type, are particularly expensive, energy-intensive and bulky, and present a high risk in terms of the safety of property and people. They are difficult to use outside of an industrial installation that is not very modular and relatively inefficient.

The objects assigned to the present invention therefore aim to remedy the various drawbacks listed above and to propose a new cooling system which, while being particularly efficient, is particularly simple to implement, inexpensive and compact.

Another object of the invention aims to provide a new cooling system whose operation is particularly easy to adapt to different uses.

Another object of the invention aims to provide a new cooling system of robust design whose implementation is easy and carried out with excellent energy efficiency.

Another object of the invention aims to provide a new cooling system that is both reliable and economically competitive.

Another object of the invention aims to provide a new cooling system whose maintenance cost is reduced.

Another object of the invention aims to provide a new cooling system which is particularly resistant to wear and whose efficiency is substantially constant over time, even if it is subjected to prolonged use and/or successive.

Another object of the invention is to provide a new cooling system with optimized efficiency, thus allowing the use of a more accurate dimensioning according to its use.

Another object of the invention aims to provide a new cooling system that is particularly efficient, space-saving and which can be easily adapted for use on different scales.

Another object of the invention aims to provide a new cooling system which is particularly useful in the field of motor vehicles, in particular as regards energy efficiency and pollution control.

Another object of the invention aims to provide a new cooling system which operates under optimal safety conditions.

Another object of the invention aims to provide a new air conditioning system having in particular high energy efficiency as well as excellent air conditioning capacity.

Another object of the invention aims to provide a new engine assembly that is particularly low in pollution, easy to produce and has high energy efficiency.

Another object of the invention aims to provide a new method for adapting an internal combustion engine that is easy to implement, making it possible to obtain an improvement in the overall performance of the engine, in particular in the fields of energy efficiency and the limitation of polluting discharges.

Another object of the invention aims to provide a new cooling process which is particularly inexpensive in terms of energy, easy to implement and to adapt to a large number of applications.

Another object of the invention aims to provide a new oxycombustion process that is particularly efficient, controlled, very low in pollution, and has excellent overall energy efficiency.

The objects assigned to the invention are achieved using a cooling system comprising at least:
- a Stirling heat pump designed to cool an inlet gas to a cryogenic temperature in order to form a cryogenic liquid,
- a primary electric motor, intended to operate said Stirling heat pump,
- a primary pump intended to circulate said cryogenic liquid under pressure, and
- A cooling means, intended to cool said primary electric motor using the cryogenic liquid from said primary pump.

The objects assigned to the invention are also achieved with the aid of a high power air conditioning system, characterized in that it comprises the cooling system described above and below, the cooling energy of the system high power air conditioning being supplied via the evaporator.

The objects assigned to the invention are also achieved with the aid of a motor assembly characterized in that it comprises at least:
- the cooling system as described above and below, said cooling system being designed to produce liquefied oxygen, and
- an internal combustion engine, downstream of said cooling system and comprising a combustion chamber,
the cooling system being connected to said internal combustion engine so as to be able to inject said liquefied oxygen into said combustion chamber.

The objects assigned to the invention are also achieved with the aid of a method for adapting an internal combustion engine comprising at least one intake manifold and one combustion chamber, said method for adapting being characterized in what it includes at least:
- a step of closing or removing said engine intake manifold,
- an installation step in which the cooling system as described above and below is connected to said internal combustion engine, at the level of said closed or removed intake manifold and therefore upstream of said combustion chamber , so as to be able to inject into the latter liquefied oxygen produced by said cooling system.

The objects assigned to the invention are also achieved using a cooling process comprising at least:
- a step of cooling an inlet gas using at least one Stirling heat pump, so as to form a cryogenic liquid, said Stirling heat pump being powered by a primary electric motor,
- a pumping step for circulating said cryogenic liquid under pressure, and
- A cooling step during which said primary electric motor is cooled using the cryogenic liquid from said pumping step.

The objects assigned to the invention are also achieved using an oxycombustion process comprising the cooling process as described above, the oxycombustion process further comprising a step of injecting liquefied oxygen during of the cooling process within a combustion chamber of an internal combustion engine.

Other features and advantages of the invention will appear and emerge in more detail on reading the description given below, with reference to the appended drawings, given solely by way of illustrative and non-limiting examples, in which:

is a simplified schematic illustration of the general principle of a cooling system of the invention.

is a schematic illustration of a particular embodiment of the cooling system of the invention, with helium cooling.

is a schematic illustration of another particular mode of the cooling system of the invention, with a separation device, all integrated within an example of an engine assembly of the invention.

is a schematic illustration of yet another particular mode of the cooling system of the invention, with water electrolysis and methanization, all integrated within another example of an engine assembly of the invention.

is a schematic illustration of the separation device of Figure 3.

is a schematic illustration of an enlarged detail of Figure 5.

is a schematic illustration of part of the separation device of Figure 3.

is a section along a plane B of the separation device of Figure 7.

is a detailed schematic illustration of an example of the principle of operation of a magnetic separation device according to the invention.

is a schematic illustration of the engine in Figure 3.

As illustrated in the figures, the invention relates, according to a first aspect illustrated in the figures, to a cooling system 1 comprising at least:
- a Stirling 2 heat pump designed to cool an inlet gas G _e down to a cryogenic temperature in order to form a cryogenic liquid L ,
- a primary electric motor 3, intended to operate said Stirling heat pump 2.

Thus, the cooling system 1 of the invention is advantageously designed to cool said inlet gas G _e until the latter liquefies and more precisely so that it reaches a cryogenic temperature (also called cryotemperature) for constitute said cryogenic liquid L. Obviously, said inlet gas G _e is preferably formed of at least one compound which can reach a cryogenic temperature in liquid form, that is to say quite low. Said cryogenic liquid L , and the statements relating to cryogenics in general, preferably relate(s) to temperatures below -50° C., more preferably -100° C., even more preferably -150° C. or even -153° C. .15°C (i.e. 120 K). In other words, said cryogenic temperature is advantageously below -50°C, more preferably -100°C, even more preferably -150°C or even more preferably -153.15°C (i.e. say 120K). For example, the cryogenic temperature, to which the cryogenic liquid L is therefore advantageously brought by means of said Stirling heat pump 2, is between -150° C. and -270° C., more preferably between -170 and -250° C., and more preferably still between -196 and -210°C.

Said Stirling heat pump 2 is preferably a cold machine, and therefore advantageously designed to generate cold (sometimes called " Stirling cold ") according to the Stirling cycle but in the opposite direction of operation of a Stirling engine, since the cycle of Stirling is reversible. Preferably, said Stirling heat pump 2 thus requires, in order to generate cold, a mechanical drive provided by said primary electric motor 3. Said Stirling heat pump 2 is therefore advantageously designed for, alone or in combination with d any other cooling devices, cooling said inlet gas G _e , at least until it liquefies, and preferably before it solidifies, and more precisely at said cryogenic temperature.

The invention also relates as such, according to a second aspect illustrated in the figures, to a cooling method comprising at least one step of cooling an inlet gas G _e using at least one heat pump Stirling 2, so as to form a cryogenic liquid L , said Stirling heat pump 2 being powered by a primary electric motor 3. The cooling process is obviously preferably implemented by means of the cooling system 1 mentioned above, and described in more detail below. Thus, preferably, the description which follows and which precedes concerning the cooling system 1 therefore also applies to the cooling method of the invention, and vice versa.

According to the invention, the cooling system 1 further comprises at least:
- a primary pump 4 intended to circulate said cryogenic liquid L under pressure, and
- a cooling means 5, intended to cool said primary electric motor 3 using the cryogenic liquid L from said primary pump 4.

According to the invention, the cooling method further comprises:
- a pumping step for circulating said cryogenic liquid L under pressure, and
- A cooling step during which said primary electric motor 3 is cooled using the cryogenic liquid L from said pumping step.

Naturally, said pumping step is preferably implemented using said primary pump 4. Of course, said cooling step is preferably implemented using said cooling means 5, which may for example comprise a heat exchanger (not shown) surrounding the primary electric motor 3. Said cooling means 5 also advantageously comprises a recirculation means, for example a pipe, designed to recover the cryogenic liquid L at an outlet of the heat pump. Stirling heat 2 and inject it into said heat exchanger. Said primary pump 4 is preferably a high pressure pump, capable of putting said cryogenic liquid L under a pressure greater than 40 bars, preferably greater than 70 bars, more advantageously greater than 100 bars, and for example between 100 and 3000 bars . Said pumping step is therefore advantageously a high pressure pumping step, to bring the cryogenic liquid L to one of the aforementioned pressure ranges. Optionally, the cooling means 5 is designed so as to also cool said Stirling heat pump 2 itself using said cryogenic liquid L coming from said primary pump 4, thereby accelerating the condensation of the cryogenic liquid L at the within said Stirling heat pump 2 and allowing the latter to minimize losses (by heating for example).

One of the advantages of the cooling configuration established by the invention is that cryogenic liquids very often have a very low viscosity, that of liquefied air (forming for example said cryogenic liquid L ) being for example approximately 20 times lower to the viscosity of water in the liquid state. Thus, it is possible, thanks to the cooling system 1 and to the cooling method of the invention, to easily pressurize said cryogenic liquid L with said primary pump 4, and this at a controlled energy cost not only because of the low viscosity cryogenic liquids implemented, but also because of the operating temperatures of the primary pump 4, which are advantageously very low and allow the implementation of said primary pump 4 under conditions at the limits of superconductivity, thanks to the cooling of said primary pump 4 itself by said cryogenic liquid L.

Another advantage of the cooling configuration established by the invention is that the pressurization (preferably high pressure) of the cryogenic liquid L , which can therefore be carried out almost without loss (of electrical energy in particular) by said primary pump 4, makes it possible to maximize the efficiency of the use of said cryogenic liquid L in a wide variety of applications. One of the advantages of this pressurization of the cryogenic liquid L is that it allows the latter to cool said primary electric motor 3 sufficiently quickly.

Said primary pump 4 comprises for example a pumping means which may in particular be centrifugal, volumetric, or even vacuum. In a particularly advantageous manner, the primary pump 4 comprises a secondary electric motor (not shown), and the cooling system 1 is designed to cool said secondary electric motor using the cryogenic liquid L coming from said Stirling heat pump 2 Thus, preferably during the cooling step, the cryogenic liquid L coming from said Stirling heat pump 2 cools said secondary electric motor.

According to this configuration, within the cooling system 1, the cryogenic liquid L advantageously makes it possible to operate the primary electric motor 3, and preferably also the secondary electric motor, at cryogenic temperatures. Said electric motor(s) therefore advantageously operating under conditions close to superconductivity due to their low operating temperature, this configuration significantly reducing the losses in the magnetic circuit (known as “ iron ” losses) and the losses by Joules effect (known as “ copper ” losses, due to electrical resistance) of the electric motor(s) 3. Thus, from an energy point of view, the cooling system 1 operates almost without losses other than friction losses, which are moreover very low within the primary pump 4 and even within the Stirling heat pump 2 when said cryogenic liquid L has a low viscosity. The cooling system 1 and the cooling method can therefore be implemented with a minimum of electrical energy, without substantial loss of the latter.

Said primary 3 and secondary electric motors are preferably separate, to allow better control of the cooling system and of the cooling process, but alternatively, they can be formed by the same single electric motor, which performs the two functions of switching on the said Stirling heat pump 2 and starting up said primary pump 4 or more precisely its pumping means.

Particularly advantageously, the cooling system 1 further comprises an evaporator 6 intended to evaporate at least part of said pressurized cryogenic liquid L coming from said primary electric motor 3, so as to form an outlet gas G _s and to recover cooling energy. Said evaporator 6 can be formed by one unit or a plurality of units, each unit advantageously forming a specific heat exchanger. Said evaporator 6 can be considered as being a global heat exchanger, one of the main functions of which is to heat up said cryogenic liquid L so as to cause it to evaporate in the form of said outlet gas G _s . Said evaporator 6 can also be designed to heat and transfer cooling energy from said output gas G _s (which remains relatively cold in evaporator 6, for example around -10 to -120° C.) to another compound , or in other words, to transfer heat from this other compound to said outlet gas G _s .

According to certain particular embodiments, examples of which are illustrated in particular in FIGS. 1 to 4, said evaporator 6 comprises at least one primary heat exchanger 7 intended to collect on the one hand said inlet gas G _e to cool it before its entry in said Stirling heat pump 2, and secondly at least a portion of said cryogenic liquid L , from said primary electric motor 3, to heat it. Advantageously, said evaporator 6 further comprises at least one secondary heat exchanger 8 intended to heat said outlet gas G _s or at least part of said cryogenic liquid L coming from said primary heat exchanger 7 using a heat source of heat Q.

According to the embodiment illustrated in FIG. 1, the cooling system 1 comprises a supply module 9 for said heat source Q . Particularly advantageously, said supply module 9 is formed by a device for producing solar energy 10, a device for recovering combustion heat 51, for example from an internal combustion engine 50, or a device for recovering waste heat from cooling system 1 or another system.

According to an embodiment illustrated in FIG. 2, the cooling system 1 comprises a helium liquefaction device 30, which comprises at least:
- a heat exchanger 31 intended to collect on the one hand gaseous helium He to cool it to a cryotemperature, for example 120 K or below (or any other cryogenic temperature already mentioned), and on the other hand the cryogenic liquid L under pressure coming from the primary electric motor 3 to heat it,
- an isenthalpic expansion module 32, intended to carry out the isenthalpic expansion of the cooled helium He gas coming from the heat exchanger 31, in order to liquefy said helium He gas.

Particularly advantageously, said heat exchanger 31 therefore forms part of said evaporator 6, and can be formed for example by said primary heat exchanger 7 or said secondary heat exchanger 8 or even constitute a separate unit. In other words, said evaporator 6 comprises said heat exchanger 31.

Preferably, said helium liquefaction device 30 further comprises at least one or more of:
- a circuit 33 for cooling a magnetic element 34, such as a medical imaging magnet, using liquefied helium He from said isenthalpic expansion module, so that the liquefied helium He is sufficiently heated to be vaporized into helium He gas,
- a secondary compressor 36, intended to compress the helium He gas coming from said cooling circuit 33 and to send it to said heat exchanger 31, and
- a secondary turbine 35, positioned upstream of said isenthalpic expansion module 32 and intended to recover mechanical energy from the cooled gaseous helium He coming from the heat exchanger 31, said secondary turbine 35 supplying (at least partly ) said secondary compressor 36 in energy (mechanical, directly, or electrical, indirectly for example via an electrical generating unit).

According to the embodiments illustrated in FIGS. 1 to 4, the cooling system 1 comprises a mechanical energy recovery device 12 for recovering the mechanical energy produced by a displacement of said outlet gas G _s . Preferably, the cooling method thus comprises, downstream of said cooling step, a step for recovering mechanical energy produced by a displacement of said outlet gas G _s . Preferably, said displacement of outlet gas G _s is caused by the passage of at least part of said cryogenic liquid L in the gaseous state in the form of said outlet gas G _s and/or by heating and/or expansion of said second output gas component G _s . The displacement of said outlet gas G _s is thus advantageously the source of mechanical work exploited by said mechanical energy recovery device 12.

Such a configuration makes it possible to obtain a particularly favorable energy balance, i.e. with little waste and losses and maximum energy efficiency. For example, said primary pump 4 is at least partly actuated using said mechanical energy recovery device 12. Thus, according to this last example, said pumping step is less partly carried out using the energy recovered during said mechanical energy recovery step.

According to the embodiment illustrated in FIG. 4, said mechanical energy recovery device 12 comprises at least one electric generator 13. Said mechanical energy recovery device 12 further comprises, for example, a primary turbine 14, linked to said generator electric 13, said primary turbine 14 being rotated by said outlet gas G _s . Alternatively, the mechanical energy recovered by said mechanical energy recovery device 12 is reused in mechanical form. Said mechanical energy recovery device 12, and more specifically said electrical generator 13, is thus advantageously designed to produce electrical energy produced E _ep from the recovered mechanical energy.

Advantageously, the cooling system 1 comprises, upstream of said Stirling heat pump 2, a primary compressor 15 designed to compress said inlet gas G _e , as illustrated in FIGS. 1 to 4. This compressor 35 advantageously makes it possible to facilitate the entry of the inlet gas G _e , for example air, within the cooling system 1, with a view to producing said cryogenic liquid L. Preferably, said primary compressor 15 is at least partly actuated using said mechanical energy recovery device 12, for example by transmission of mechanical and/or electrical energy E _m/e . Thus, advantageously, the cooling process comprises, upstream of said cooling step, a compression step during which said inlet gas G _e is compressed, said compression step being more preferably at least partly carried out using the energy recovered during said mechanical energy recovery step. The energy balance and the overall efficiency of the cooling system 1 are thereby further improved.

According to the embodiment illustrated in FIG. 4, the cooling system further comprises a module 16 for the electrolysis of water H ₂ O into dihydrogen H ₂ and dioxygen O ₂ supplied with electricity at least by said electric generator 13 Thus, said electrical generator 13 supplies the electrical energy produced E _ep , to the electrolysis module 16 advantageously continuously, which makes it possible to save significant amounts of energy since there is no longer any need to supply completely independently of said electrolysis module 16. Such a configuration is particularly advantageous because the electrolysis of water is very costly in terms of electrical energy.

According to the embodiment illustrated in Figure 4, the cooling system 1 advantageously further comprises a heat exchange module 17 designed to:
- cooling at least until liquefaction the oxygen O ₂ from the electrolysis module 16 so as to form liquefied oxygen O ₂ , and
- heating the output gas G _s coming from the mechanical energy recovery device 12.

Still according to the embodiment of Figure 4, the cooling system 1 also comprises a methane reforming unit 18, designed to react carbon dioxide CO ₂ with dihydrogen H ₂ from said electrolysis module of the water 16 to form methane CH ₄ and water H ₂ O . The methane CH ₄ thus formed can advantageously be injected into an internal combustion engine 50 as fuel, while the liquefied oxygen O ₂ can be injected into said internal combustion engine 50 as oxidizer.

The invention also relates as such, according to a third aspect illustrated by the examples in FIGS. 3 and 4, to an engine assembly 60 comprising at least:
- the cooling system 1, as described previously and optionally below, said cooling system 1 being designed to produce liquefied oxygen O ₂ , and
- an internal combustion engine 50, downstream of said cooling system 1 and comprising a combustion chamber 25.

The motor assembly 60 is obviously preferably implemented by means of the cooling system 1 mentioned above, and described in more detail below. Thus, preferably, the foregoing (and optionally following) description concerning the cooling system 1 and the cooling method therefore also applies to the motor assembly 60 of the invention, and vice versa.

According to this third aspect of the invention, the cooling system 1 is connected to said internal combustion engine 50 so as to be able to inject said liquefied oxygen O ₂ into said combustion chamber 25 .

According to the embodiment illustrated in FIG. 3, said liquefied oxygen O ₂ comes from said water electrolysis module 16.

Advantageously, the cooling system 1 is also designed to be able to also inject said methane CH ₄ within said combustion chamber 25.

For example, the internal combustion engine 50 is a four-stroke engine, a two-stroke engine, a rotary piston engine (as shown), a gas turbine engine, or a Stirling engine. Said internal combustion engine 50 is thus advantageously intended to be powered by an oxidant and a fuel, one and/or the other possibly coming from said cooling system 1.

According to a particular embodiment, an example of which is illustrated in FIG. 3, compatible in particular with the third aspect of the invention and/or with the first and second aspects alone, said cryogenic liquid L coming from said primary electric motor 3 is formed of at least a first component C ₁ and a second component C ₂ which are distinct and in the liquid state.

According to the embodiment illustrated in FIG. 3, the cooling system 1 further comprises a separation device 19 designed to separate said first and second components C ₁ , C ₂ in the liquid state by magnetism, one of said first and second components C ₁ , C ₂ in the liquid state having a much greater paramagnetic character than the other of said first and second components C ₁ , C ₂ . Thus, according to this last embodiment, the cooling method further comprises a step of separating said first and second components C ₁ , C ₂ in the liquid state by magnetism. Of course, said separation step is preferably implemented by means of said separation device 19.

According to a first example, such as that illustrated in FIG. 3, said inlet gas G _e is formed by air, said first component C ₁ being mainly formed by dioxygen O ₂ , while said second component C ₂ is very predominantly formed by dinitrogen N ₂ . Preferably, said second C ₂ component thus further comprises argon Ar and/or carbon dioxide CO ₂ , each of which is found in the air in a much lower proportion than that of dinitrogen N ₂ . According to a second example, said inlet gas G _e is formed mainly by natural gas or bio-methane (that is to say resulting from an essentially biological process for producing methane), said first component C ₁ being mainly formed from methane CH ₄ while said second component C ₂ , in particular in the liquid state, is formed from the effluents of natural gas or bio-methane, said effluents being in the present case preferentially formed from the liquid fraction of the gas natural or bio-methane discharged following treatment of the input gas G _e (cooling until liquefaction) stripped of its main recoverable product, namely here methane CH ₄ . Indeed, natural gas and biomethane are usually each formed by a mixture of several chemical species, among which methane CH ₄ is normally predominant.

Said separation device 19 preferably further comprises an induction pump 20, for example single-phase or three-phase, designed to expel said most paramagnetic component, among said first and second components C ₁ , C ₂ , out of separation device 19, preferably while pressurizing it. Advantageously, said separation device 19 comprises a magnetic trap 21 designed to emit a magnetic field 100 so as to retain the most paramagnetic component, among said first and second components C ₁ , C ₂ , substantially within a trapping portion 22 of said separation device 19. Advantageously, said separation step thus comprises a magnetic trapping step in which a magnetic field 100 is emitted so as to retain the most paramagnetic component, among said first and second components C ₁ , C ₂ , substantially within a trapping zone 23, which is preferably formed by or surrounded by said trapping portion 22. Naturally, said magnetic trapping step is advantageously implemented using said magnetic trap 21. Preferably, said separation device 19 comprises a settling means 24 of said cryogenic liquid L , at least a portion of said settling means 24 forming said trapping portion 22. The cooling method therefore advantageously comprises a step of settling said cryogenic liquid L , said settling step being preferably implemented by means of said settling means 24, which comprises for example a settling vessel. Advantageously, said settling and trapping steps are at least partly concomitant. Advantageously, said magnetic trap 21 and said induction pump 20 are used in combination, said induction pump 20 being downstream of magnetic trap 21 and making it possible to complete the step of separating said first and second components C ₁ , C ₂ . According to an example of operation given by way of illustration only and not limiting, to finalize this separation, the first component C ₁ in the liquid state (liquid oxygen O ₂ in the case where the inlet gas G _e is air) is sucked into the magnetic trap 21 by the induction pump 20 whose magnetic field, thanks to a phase shift, generates a magnetic wave which travels along an evacuation pipe forming an outlet of said first component C ₁ at the liquid state, thus attracting the first component C ₁ in the liquid state (formed for example of liquid dioxygen O ₂ ) out of the settling means 24 while putting it under pressure. The speed of movement of the first component C ₁ in the liquid state is preferably proportional to the frequency of the current supplying the induction pump 20 and to the Lorentz forces.

As illustrated in Figure 9, the magnetic trap 21, and more precisely said trapping portion 22, advantageously comprises a magnetic network formed of small magnets 26 which constitute small cells in three dimensions, and which make it possible to emit said magnetic field 100 The set of said magnets 17 can form a cube, a cylinder, or a cone, and the cells are smaller and smaller as you approach the bottom. Such a configuration is similar to a magnetic filter with increasingly fine meshes. In FIG. 9, the indices P+ and P- advantageously represent partial pressure gradients due to the concentration respectively of liquid oxygen O ₂ (or more generally of the first component C ₁ ) and of nitrogen N ₂ (or more generally of said second component C ₂ ) liquid within the magnetic trap 21, while the horizontal arrows resulting from the signs O ₂ and N ₂ represent the respective hydraulic velocities of the liquid dioxygen O ₂ and the liquid dinitrogen N ₂ , respectively, the waveform at left representing the distribution of the velocities of the first and second components C ₁ , C ₂ mixed in the liquid state just before their magnetic separation. Advantageously, under the effect of magnetic field 100, said liquid oxygen O ₂ (or more generally said first component C ₁ ) approaches a first wall 27 of magnetic trap 21 behind which said magnets 26 are located, while the dinitrogen N ₂ (or more generally the second component C ₂ ) approaches a second wall 28 of the magnetic trap 21 opposite the first wall 27 and devoid of magnet, the magnetic field 100 exerting a magnetic force F _m on the paramagnetic molecules of dioxygen O ₂ (or more generally on the most paramagnetic of said first and second components C ₁ , C ₂ , preferably said first component C ₁ ) only, and not on the molecules of dinitrogen N ₂ . Thus, according to this variant with a magnetic separation device 19, the separation step and/or the separation device 19 of the invention uses(s) the paramagnetic capacity of the liquid dioxygen O ₂ (and more generally of said first component C ₁ in the liquid state), which is thus retained between magnet poles and/or is attracted by a magnetic field 11, to separate it from the dinitrogen N ₂ and from the argon Ar (and more generally from said second component C ₂ in liquid state). Indeed, the liquid argon Ar and the liquid nitrogen N ₂ being mainly non-magnetic, they are advantageously not retained by the magnetic field 100.

Said induction pump 20 comprises, according to an advantageous example illustrated in FIG. 7, a three-phase wire winding 70 for collecting said first component C ₁ within settling means 6, and downstream of this winding 70 one or more three-phase coils 71, as illustrated in FIG. 6. Such a configuration preferably makes it possible both to improve the final separation of said first and second components C ₁ , C ₂ , and to pressurize, that is to say at a significant rate, said first liquid component C ₁ finally separated from said second liquid component C ₂ .

This specific configuration with a separation device 19 operating using magnetism is particularly advantageous, since the operating temperatures of the magnetic separation device 19, and in particular of said magnetic trap 21 and of said induction pump 20, are very low (cryotemperatures). Thus, the conductive parts of the separation device 19, in particular in the case of magnets and more particularly of electromagnets, are at the limits of the natural superconductivity of copper or aluminum, and electric currents of all magnitudes can therefore be used and generate large magnetic forces with little heating and therefore little electrical and thermal losses.

According to the embodiment illustrated in FIG. 3, the engine assembly 60 is designed so that the cooling system 1 can inject, within said combustion chamber 25, the first component C ₁ in the state coming from of the separation device 19, said first component C ₁ in the liquid state advantageously forming said liquefied oxygen O ₂ Advantageously, said injected first component C ₁ is therefore intended to serve as oxidizer within the internal combustion engine 50.

In a particularly advantageous manner, said separation device 19 is therefore designed to inject said second component C ₂ in the liquid state into said evaporator 6 and not to inject said first component C ₁ in the liquid state into said evaporator 6. For example , the motor assembly 60 is designed so that the second component C ₂ is formed (mainly) by said liquid nitrogen N ₂ and that it is introduced into the evaporator 6, while the first component C ₁ is formed by said dioxygen O ₂ liquid and injected directly into said internal combustion engine 50, to achieve oxycombustion, as illustrated in Figure 3.

Thus, a specific alternative of the third aspect of the invention relates to an engine assembly 60 comprising:
- the cooling system 1, and
- an internal combustion engine 50, downstream of said cooling system 1 and comprising a combustion chamber 25
the cooling system 1 being connected to said engine 26 so as to be able to inject said first component C ₁ into said combustion chamber 25 . The latter is obviously preferentially formed by dioxygen O ₂ .

Advantageously, said engine 50 comprises an exhaust outlet 42 designed to evacuate at least one exhaust component C _e in the gaseous state out of said combustion chamber 25. Even more advantageously, downstream of said exhaust outlet exhaust 42, said evaporator 6 is designed to cool said exhaust component C _e from said exhaust outlet 42 and heat said second component C ₂ from said separation device 19. Said exhaust outlet 42 thus advantageously forms part of said combustion heat recovery device 51.

The fuel of the internal combustion engine 50 may in particular be a hydrocarbon, for example methane CH ₄ , or dihydrogen H _{2 .} When the fuel is a hydrocarbon and in particular methane CH ₄ , the exhaust component C _e in the gaseous state, which contains the combustion products of the engine 26, will mainly be formed of water and carbon dioxide CO ₂ . When the fuel is dihydrogen H ₂ , the exhaust component C _e in the gaseous state will be formed mainly or almost exclusively of water. The absence of dinitrogen N ₂ in the combustion chamber, thanks to the direct injection of pure liquid (or possibly gaseous) dioxygen O ₂ is one of the advantages of the engine assembly 60 of the invention (of which two specific variants are illustrated in Figures 3 and 4), particularly with regard to the reduction in pollution relating to nitrogen oxides, also called " NO _x ". Indeed, the internal combustion engine 50 of the engine assembly 60, in the absence of nitrogen in the combustion chamber 25, produces no or almost no NOx.

Advantageously, the engine assembly 60 comprises a combustion heat recovery device 51, preferably that described above, to recover the combustion heat of the exhaust component C _e coming from said combustion chamber 25.

Preferably, the engine assembly 60 is designed so that the evaporator 6 cools said exhaust component C _e at least until liquefaction of a primary portion of the latter, as illustrated in FIGS. 3 and 4. Preferably , the engine assembly 60 is designed to use said liquefied primary portion in order to liquefy a secondary portion of said exhaust component C _e , said primary and secondary portions being distinct. Said primary portion is advantageously mainly formed of carbon dioxide CO ₂ , while said secondary portion is mainly formed of water, as illustrated in FIGS. 3 and 4. Even more advantageously, said combustion heat recovery device 51 comprises a reinjection device (not shown) designed to sweep said combustion chamber 25 with said primary portion and/or said secondary portion (in liquid or alternatively gaseous state) in order to expel said exhaust component C _e from said chamber combustion engine 25. Such a configuration makes it possible to improve the operation of the internal combustion engine 50 by effectively expelling the latter the exhaust component C _e . For example, in particular when the fuel is a hydrocarbon, said reinjection device is designed to inject the liquid primary portion formed of carbon dioxide, within said combustion chamber 25, to optimize the scanning of the latter, that is that is, to expel all of the gases burned by the combustion and which form the exhaust component C _e in the gaseous state.

The invention also relates as such, according to a fourth aspect, to a method for adapting an internal combustion engine 50 comprising at least one intake manifold and one combustion chamber 25, said method for adapting at least less :
- a step of closing or removing said engine intake manifold 26,
- an installation step in which the cooling system 1 as previously described is connected to said internal combustion engine 50, at the level of said closed or removed intake manifold and therefore upstream of said combustion chamber 25, so to be able to inject into the latter liquefied oxygen O ₂ produced by said cooling system 1.

Advantageously, at the end of said installation step, said internal combustion engine 50 and the cooling system 1 form an engine assembly 60 as described above.

For example, said liquefied oxygen O ₂ can be formed by said first component C ₁ coming from the separation device 19, as illustrated in FIG. 3, or else by the oxygen O ₂ formed by the water electrolysis module 16 and liquefied by said heat exchange module 17, or a combination of both. Obviously, the description which follows and which precedes concerning the cooling system 1, the motor assembly 60 and the cooling method therefore also applies to the adaptation method of the invention, and vice versa.

The invention also relates as such, according to a fifth aspect, to an oxycombustion process comprising the cooling process as described above, the oxycombustion process further comprising a step of injecting liquefied dioxygen O ₂ during the cooling process within a combustion chamber 25 of an internal combustion engine 50. Of course, the following and preceding description concerning the cooling system 1, the engine assembly 60, the cooling process and even the adaptation method therefore also applies to the oxycombustion method of the invention, and vice versa. For example, said inlet gas G _e being formed by air, said first component C ₁ being mainly formed by oxygen O ₂ , and during said injection step, said first component C ₁ is injected into said combustion chamber 25.

For example, as illustrated in FIG. 10, the internal combustion engine 50 has a rotary piston 44 (in the shape of a Reuleaux triangle). The internal combustion engine 50 with rotary piston 44 of the variant illustrated in FIG. 10 comprises two spark plugs 39 in opposition, two common injections of fuel and oxidizer 40, 41 also in opposition, and two exhaust outlets 42 also in opposition and designed to evacuate the exhaust component C _e in the gaseous state, as previously described. Said oxidant is preferably formed by liquid dioxygen O ₂ , formed for example by said first component C ₁ . Oxycombustion makes it possible here to overcome the recurring low compression problems of conventional rotary piston engines, in particular by adapting the speed of rotation of the rotary piston 44.

The cooling system 1 is also suitable for the production of small quantities of said liquefied first component C ₁ , or, after the latter has returned to the gaseous state, for the production of small quantities of said first component C ₁ in the gaseous state but compressed (i.e. under relatively high pressure).

The invention also relates as such, according to a fifth aspect not illustrated here, to a high power air conditioning system comprising the cooling system previously described, the cooling energy of the high power air conditioning system being supplied via said evaporator 6.

By convention, in a purely indicative and non-limiting manner, the signs (g) and (liq) are indicated in the figures to indicate respectively the gaseous and liquid states of the various components. In the figures, the arrows positioned on either side of the continuous lines preferably indicate the direction of a flow, for example a flow of He( _g ), that is to say a flow of helium He at the gaseous state.

The terms of the first, second, third, fourth, fifth, primary, secondary, tertiary type of the preceding description are preferably used for distinctive purposes only, and not to designate a rank or an ordinal numbering. A second element can for example be introduced without necessarily a first element of the same nature being also introduced or even implicitly present.

In summary, the invention is related to the problems of liquefied gas production, pollution control and energy efficiency of combustion engines, and more generally energy saving.

Claims (30)

Cooling system (1) comprising at least:
- a Stirling heat pump (2) designed to cool an inlet gas (G _e ) to a cryogenic temperature in order to form a cryogenic liquid (L),
- a primary electric motor (3), intended to operate said Stirling heat pump (2),
- a primary pump intended to circulate said cryogenic liquid (L) under pressure, and
- a cooling means (5), intended to cool said primary electric motor (3) using the cryogenic liquid (L) from said primary pump (4). Cooling system (1) according to the preceding claim, characterized in that the primary pump (4) comprises a secondary electric motor, the cooling system (1) being designed to cool said secondary electric motor using the cryogenic liquid (L ) from said Stirling heat pump (2). Cooling system (1) according to claim 1 or 2, characterized in that it comprises a helium liquefaction device (30), which comprises at least:
- a heat exchanger (31) intended to collect on the one hand gaseous helium to cool it to a cryotemperature, for example 120 K or below, and on the other hand the cryogenic liquid (L) under pressure in coming from the primary electric motor (3) to heat it,
- an isenthalpic expansion module (32), intended to carry out the isenthalpic expansion of the cooled helium (He) gas coming from the heat exchanger (31), in order to liquefy said helium (He) gas. Cooling system (1) according to the preceding claim, characterized in that said helium liquefaction device (30) further comprises:
- a circuit (33) for cooling a magnetic element (34), such as a medical imaging magnet, using liquefied helium (He) from said isenthalpic expansion module (32), so that the liquefied helium (He) is sufficiently heated to be vaporized into gaseous helium (He),
- a secondary compressor (36), intended to compress the gaseous helium (He) coming from said cooling circuit (30) and to send it to said heat exchanger (31), and
- a secondary turbine (35), positioned upstream of said isenthalpic expansion module (32) and intended to recover mechanical energy from the cooled helium (He) gas coming from the heat exchanger (31), said turbine secondary (35) supplying said secondary compressor (36) with energy. Cooling system (1) according to any one of the preceding claims, characterized in that it comprises an evaporator (6) intended to evaporate at least part of the said cryogenic liquid (L) under pressure coming from the said primary electric motor (3 ), so as to form an exit gas (G _s ) and recover cooling energy. Cooling system (1) according to the preceding claim, characterized in that said evaporator (6) comprises at least one primary heat exchanger (7) intended to collect on the one hand said inlet gas (G _e ) to cool it before its entry into said Stirling heat pump (2), and on the other hand at least a part of said cryogenic liquid (L), coming from said primary electric motor (3), to heat it. Cooling system (1) according to the preceding claim, characterized in that the said evaporator (6) further comprises at least one secondary heat exchanger (8) intended to heat the said outlet gas (G _s ) or at least part of the said liquid cryogen (L) from said primary heat exchanger (7) using a heat source (Q). Cooling system (1) according to the preceding claim, characterized in that it comprises a supply module (9) of said heat source (Q), said supply module (9) being formed by a device for producing solar energy (10), a combustion heat recovery device (51), or a device for recovering waste heat from the cooling system (1) or from another system. Cooling system (1) according to any one of Claims 5 to 8, characterized in that it comprises a mechanical energy recovery device (12) for recovering the mechanical energy produced by a displacement of said outlet gas ( _Gs ). Cooling system (1) according to the preceding claim, characterized in that it comprises, upstream of the said Stirling heat pump (2), a primary compressor (15) designed to compress the said inlet gas (G _e ), said primary compressor (15) being at least partly actuated by means of said mechanical energy recovery device (12). Cooling system (1) according to Claim 9 or 10, characterized in that the said mechanical energy recovery device (34) comprises at least one electrical generator (13), the cooling system (1) further comprising a module electrolysis (16) of water into dihydrogen (H ₂ ) and dioxygen (O ₂ ) supplied with electricity at least by said electric generator (13). Cooling system (1) according to the preceding claim, characterized in that it further comprises a heat exchange module (17) designed to:
- cooling at least until liquefaction the oxygen (O ₂ ) from the electrolysis module (16) so as to form liquefied oxygen (O ₂ ), and
- heating the outlet gas (G _s ) coming from the mechanical energy recovery device (12). Cooling system (1) according to claim 11 or 12, characterized in that it further comprises a methane reforming unit (18), designed to react carbon dioxide (CO ₂ ) with dihydrogen (H ₂ ) from said water electrolysis module (16) to form methane (CH ₄ ) and water (H ₂ O). Cooling system (1) according to any one of the preceding claims, characterized in that the said cryogenic liquid (L) coming from the said primary electric motor (3) is formed of at least a first component (C ₁ ) and a second component (C ₂ ) distinct and in the liquid state, the cooling system (1) further comprising a separation device (19) adapted to separate the said first and second components (C ₁ , C ₂ ) in the liquid state by magnetism, one of said first and second components (C ₁ , C ₂ ) in the liquid state having a much greater paramagnetic character than the other of said first and second components (C ₁ , C ₂ ). Cooling system (1) according to Claims 5 and 14, characterized in that the said separation device (19) is designed to inject the said second component (C ₂ ) in the liquid state into the said evaporator (6) and not to inject the said first component (C ₁ ) in the liquid state in said evaporator (6). Cooling system (1) according to claim 14 or 15, characterized in that said separation device (19) further comprises an induction pump (20), for example single-phase or three-phase, designed to expel said most paramagnetic component, among said first and second components (C ₁ , C ₂ ), out of the separation device (19), preferably while pressurizing it. Cooling system (1) according to any one of claims 14 to 16, characterized in that said separation device (19) comprises a magnetic trap (21) designed to emit a magnetic field (100) so as to retain the component the most paramagnetic, among said first and second components (C ₁ , C ₂ ), substantially within a trapping portion (22) of said separation device (19). Cooling system (1) according to the preceding claim, characterized in that said separation device (19) comprises means (24) for settling said cryogenic liquid (L), at least a portion of said settling means (24) forming said trapping portion (22). Cooling system (1) according to any one of Claims 14 to 18, characterized in that the said inlet gas (G _e ) is formed by air, the said first component (C ₁ ) being mainly formed by dioxygen ( O ₂ ), while said second component (C ₂ ) is very predominantly formed by dinitrogen (N ₂ ). Cooling system (1) according to any one of Claims 14 to 19, characterized in that it is connected to an internal combustion engine (50) comprising a combustion chamber (25), the cooling system (1) being designed to inject, within said combustion chamber (25), the first component (C ₁ ) coming from the separation device (19). Cooling system (1) according to the preceding claim, characterized in that the said injected first component (C ₁ ) is intended to serve as oxidant within the internal combustion engine (50). High power air conditioning system, characterized in that it comprises the cooling system according to claim 5 and optionally any of the other preceding claims, the cooling energy of the high power air conditioning system being supplied via said evaporator (6 ). Engine assembly (60) characterized in that it comprises at least:
- the cooling system (1) according to any one of claims 1 to 21, said cooling system (1) being designed to produce liquefied oxygen (O ₂ ), and
- an internal combustion engine (50), downstream of said cooling system (1) and comprising a combustion chamber (25),
the cooling system (1) being connected to said internal combustion engine (50) so as to be able to inject said liquefied oxygen (O ₂ ) into said combustion chamber (25). Engine assembly (60) according to the preceding claim when the latter depends on any one of claims 14 to 21, characterized in that it is designed so that the cooling system (1) can inject, within said combustion chamber (25), the first component (C ₁ ) in the liquid state coming from the separation device (19), the said first component (C ₁ ) in the liquid state advantageously forming the said oxygen (O ₂ ) liquefied. Engine assembly (60) according to Claim 23 or 24 when it depends on any one of Claims 11 to 13, characterized in that the said liquefied oxygen (O ₂ ) comes from the said electrolysis module (16) of the water. Method for adapting an internal combustion engine (50) comprising at least one intake manifold and one combustion chamber (25), said adaptation method being characterized in that it comprises at least:
- a step of closing or removing said engine intake manifold (26),
- an installation step in which the cooling system (1) according to any one of claims 1 to 21 is connected to said internal combustion engine (50), at the level of said closed or removed intake manifold and therefore in upstream of said combustion chamber (25), so as to be able to inject into the latter liquefied oxygen (O ₂ ) produced by said cooling system (1). Adaptation method according to the preceding claim, characterized in that at the end of the said installation step, the said internal combustion engine (50) and the cooling system (1) form an engine assembly (60) according to the claim 24 or 25. Cooling method comprising at least:
- a step of cooling an inlet gas (G _e ) using at least one Stirling heat pump (2), so as to form a cryogenic liquid (L), said Stirling heat pump ( 2) being powered by a primary electric motor (3),
- a pumping step for circulating said cryogenic liquid (L) under pressure, and
- a cooling step during which said primary electric motor (3) is cooled using the cryogenic liquid (L) from said pumping step. Cooling method according to the preceding claim, characterized in that said cryogenic liquid (L) coming from said primary electric motor (3) is formed of at least a first component (C ₁ ) and a second component (C ₂ ) which are distinct and in the liquid state, the cooling method further comprising a step of separating said first and second components (C1, C2) in the liquid state by magnetism, one of said first and second components (C ₁ , C ₂ ) in the liquid state having a much greater paramagnetic character than the other of said first and second components (C ₁ , C2). Oxycombustion process characterized in that it comprises the cooling process according to claim 28 or 29, the oxycombustion process further comprising a step of injecting liquefied oxygen (O ₂ ) during the cooling process within a combustion chamber (25) of an internal combustion engine (50).