EP3256701A1

EP3256701A1 - Thermodynamic system

Info

Publication number: EP3256701A1
Application number: EP16705088.9A
Authority: EP
Inventors: Pierre CONVERT
Original assignee: Aqylon
Current assignee: Aqylon
Priority date: 2015-02-11
Filing date: 2016-02-11
Publication date: 2017-12-20
Also published as: CA2974154A1; US20170373562A1; WO2016128527A1

Abstract

The invention relates to a thermodynamic system (10), notably a system (10) implementing a thermodynamic Rankine cycle, comprising a circulation loop (31-36) for the circulation of a working fluid, said loop (31-36) comprising an energy production means (20), said system (10) also comprising a device for cooling said energy production means (20) and a channel (37, 38) designed to supply said cooling device with working fluid from said loop (31-36) and to return said working fluid into said loop (31-36), said cooling device being designed so as to cool said energy production means (20) by vaporisation of the working fluid inside said production means (20), said working fluid entering said energy production means (20) in the liquid phase.

Description

Thermodynamic system

The invention relates to a thermodynamic system, in particular a system implementing a thermodynamic Rankine cycle.

It is known to provide systems implementing a Rankine thermodynamic cycle in the form of circuits that allow the circulation of a working fluid. By being circulated in such circuits, the working fluid changes phase, in particular passes from the gaseous state to the liquid state, and vice versa.

These circuits usually comprise a turbine coupled to a generator, in particular an electromagnetic generator. In such circuits, the turbine is driven by the expansion of the working fluid in the gaseous state. The turbine, thus driven, transmits mechanical energy to the generator which transforms it into electrical energy, in particular via a rotating element such as a shaft.

Given the heat generated by the generator, it is appropriate to provide a cooling device. However, the known cooling devices are complex; they require in particular to provide a specific circuit for a cooling fluid.

An object of the present invention is to provide a simple cooling of the generator of a thermodynamic system, in particular of a system implementing a thermodynamic Rankine cycle. Thus, the invention relates to a thermodynamic system, in particular a system implementing a thermodynamic Rankine cycle, comprising a circulating loop of a working fluid, said loop comprising means for producing energy.

Said system further comprises a cooling device of said power generating means and a branch configured to supply said cooling device with working fluid from said loop and returning said working fluid in said loop, said cooling device being configured to cool said energy producing means by vaporization of said working fluid within said production means, said working fluid entering the liquid phase in said energy producing means.

According to the invention, said power generation means comprises a turbine, forming part of said loop, and an electric energy generator coupled to said turbine, said turbine being intended to be driven by the expansion of said working fluid in phase gaseous, said cooling device being configured to cool said generator, said generator being an electromagnetic generator comprising a stator and a rotor, said cooling device comprising a cavity formed in a body intended to form part of said rotor, said cavity being intended to receive the working fluid, said device being adapted to create a film of said working fluid in its liquid state, in said cavity, under the effect of an existing centrifugal force when the rotor is rotated relative to said stator, said device being further adapted to allow evacuation of said fluid in its gaseous state towards the outside of the cavity.

The thermodynamic system of the invention comprises a cooling device that utilizes the working fluid of the system to cool the energy producing means of said system. This allows a simple cooling of said power generation means because this cooling does not use an external circuit for circulating a cooling fluid.

On the other hand, cooling by liquid fluid requires a high flow rate; while here, it is the enthalpy of the change of state of the working fluid which is used for the cooling of the means of production of energy. This makes it possible to advantageously provide a flow rate of liquid working fluid which remains low, in particular at the inlet of the cooling device of the energy production means.

In addition, the working fluid thus evaporated can advantageously be released into the thermodynamic system, at any point where said fluid is in gaseous form.

According to various embodiments of the invention, which may be taken together or separately: the working fluid intended to be vaporized in said cooling device is fed into said energy production means, in particular in said generator, via a valve, called expansion valve,

the working fluid intended to be vaporized in said cooling device is injected into said energy production means, in particular into said generator, via a nozzle, called an injection nozzle,

said loop further comprises a condenser,

said condenser is configured to condense the working fluid when it is in the gaseous phase,

said loop further comprises a pump,

said pump is capable of increasing the pressure of said working fluid when it is in the liquid phase,

said pump is positioned downstream of said condenser,

the working fluid intended to be vaporized in the cooling device is stitched in the loop downstream of said pump,

said loop further comprises a regenerator,

said regenerator is configured to exchange thermal energy between said working fluid when it is in the gaseous phase and said working fluid when it is in the liquid phase,

said regenerator is positioned downstream of said turbine in a part of the loop configured for the circulation of the working fluid in the gaseous phase and downstream of said pump in a part of the loop configured for the circulation of the fluid in the liquid phase,

said loop further comprises an evaporator,

said evaporator is configured to evaporate the working fluid when it is in the liquid phase,

said evaporator is positioned between said pump and said turbine,

the working fluid vaporized inside said energy generating means, in particular inside said generator, by said cooling device is released in the loop upstream of said condenser,

the system according to the invention further comprises a sealing device arranged so as to ensure a seal between said turbine and said generator, said sealing device is positioned between said turbine and said generator,

said sealing device comprises a seal configured to prevent said working fluid, when in the gas phase, from circulating from said turbine to said generator,

said cavity comprises a pair of walls arranged to retain the fluid film in the liquid state,

said cooling device comprises means for injecting said fluid in the liquid state at said cavity and an evacuation channel;

said means for injecting said fluid in the liquid state at said cavity is opposed to the evacuation channel, with respect to said cavity,

the rotor comprises a shaft formed of said body and on which is mounted an electromagnetic element, said shaft having a principal direction of longitudinal extension, said main axis,

the electromagnetic element is an electromagnetic winding,

the cavity of the cooling device is positioned between said electromagnetic winding and said shaft,

said cavity extends longitudinally along said electromagnetic winding, in the direction of said main axis,

a bottom of said cavity is in contact with at least a part of said electromagnetic winding.

The invention will be better understood, and other objects, details, features and advantages thereof will become more clearly apparent in the following detailed explanatory description of at least one embodiment of the invention given to As a purely illustrative and non-limiting example, with reference to the following appended schematic drawings:

FIG. 1 is a schematic representation of an embodiment of a system according to the invention,

- Figure 2 is a schematic partial sectional view of an exemplary embodiment of a generator of a system according to the invention. As illustrated in FIG. 1, the invention relates to a thermodynamic system 10, in particular a system 10 implementing a thermodynamic Rankine cycle. This system 10 comprises a circulation loop 31 -36 of a working fluid. Said loop 31 -36 comprises a means for producing energy 20.

Said energy production means 20 advantageously comprises a turbine 22 and an electric energy generator 21 coupled to said turbine 22. Said turbine 22 is intended to be driven by the expansion of said working fluid in the gas phase.

According to the invention, said system 10 further comprises a cooling device of said generator 21. Said system 10 comprises a branch 37 configured to supply said cooling device with working fluid from the loop 31 -36 and to return said working fluid in said loop 31 -36, after cooling said generator 21. The return of said working fluid in said loop 31 -36 is via part of the branch referenced 38 in FIG.

Said cooling device is configured to cool said generator 21 by vaporizing said working fluid inside said generator 21. It should be noted that said working fluid enters the liquid phase in said generator 21.

In order to locate the elements comprised by the circulation loop 31 -36 of the fluid, we will describe the elements that it comprises and the sections 31-36 which connect said elements to each other.

Thus, said loop comprises a first section 31 in which circulates the working fluid in the vapor state, high temperature and high pressure. This section 31 conducts the working fluid to the turbine 22, through which it expands, while driving the turbine in a rotational movement, movement advantageously transmitted to the generator 21 via a transmission shaft.

The working fluid leaves said turbine 22 and circulates in a section 32 in the vapor state, high temperature and low pressure. This section 32 conducts the fluid to a condenser 50 whose function is to completely condense said fluid. It should be noted, as an option, that said fluid first passes through a regenerator 70 before being passed through an intermediate section 33 to said condenser 50.

Once fully condensed, said working fluid flows from the condenser 50 to a pump 60, in particular via a section 34. Said working fluid is then in the liquid state, low temperature and low pressure. After passing through said pump 60, the working fluid is still in the state of liquid, low temperature but at high pressure.

It is circulated via a section 35 towards an evaporator 80 from which it leaves in the form of steam, high temperature and high pressure, then to be directed to the turbine 22, in particular via the section 31 already mentioned.

In the case where said loop 31 -36 comprises a regenerator 70, said working fluid passes firstly through said regenerator 70 before being circulated to said evaporator 80 via an intermediate section 36.

According to the embodiment shown here, it is the branch 37 which is configured to supply the cooling device with working fluid from said loop 31 -36. It should however be noted that said cooling device may be supplied by a stitching at other points of the loop 31 -36, as long as the working fluid is in the liquid state and at a pressure slightly greater than that which prevails at the level of the condenser 50. Indeed, the purpose is to allow said working fluid thus stitched, to circulate inside said generator 21.

According to the same embodiment, it is via the portion of the branch 38 that said working fluid is returned in said loop 31 -36, after cooling. Cooling being, according to the invention, by vaporization of said working fluid inside said generator 21, said working fluid comes out in the gaseous state, in the form of steam, and can be reinjected at any point of the loop 31 -36 where the fluid flows in the gaseous state, in particular at low pressure, as here upstream of said condenser 50, that is to say in section 32, or 33 in the event of the presence of a regenerator 70 .

Any other nozzle configuration of the fluid in the liquid state is conceivable, like any other return configuration of the same fluid, in the gaseous state, to said loop 31 -36, without departing from the scope of the invention. It should be noted that the working fluid intended to be vaporized in said cooling device is advantageously brought into said generator 21 via a valve 40, called the expansion valve 40. This expansion valve 40 is here positioned in the branch 37, which is actually a bypass branch of a portion of the working fluid, between the output of the pump 60 and said generator 21. The working fluid to be vaporized in said cooling device may be injected into said generator 22 via a nozzle 41, called the injection nozzle 41, shown in FIG. 2.

In the illustrated example, the condenser 50 allows the evacuation of the heat accumulated inside the generator 21. Thus, in addition to its function inside the thermodynamic loop 31-36, the condenser 50 controls the cooling of the generator 21.

It should be noted, again, that the pump 60 is able to increase the pressure of said working fluid when it is in the liquid phase, and that it is advantageously positioned downstream of said condenser 50. To avoid any cavitation problem of said pump 60, all the fluid must pass from the gaseous state to the liquid state at the condenser 50, in particular at the pressure of the condenser 50. To do this, the condenser 50 is in connection with a cooling circuit which comprises a cold source 91 dimensioned accordingly, in particular taking into account the double function of the condenser 50. Said cooling circuit is a circuit external to the loop 31 -36.

It should also be noted that the regenerator 70, optional, makes it possible to exchange thermal energy between said working fluid when it is in the gaseous phase and said working fluid when it is in the liquid phase. Said regenerator 70 is here positioned downstream of the turbine 22 in a portion of the loop 31 -36 configured for the circulation of the working fluid in the gas phase, in particular between the section 32 and the intermediate section 33 and downstream of said pump 60 in a portion of the loop 31 -36 configured for the circulation of fluid in the liquid phase, in particular between the section 35 and the intermediate section 36. It should also be noted that the evaporator 80 is configured to evaporate the working fluid when it is in the liquid phase. Said evaporator 80 is positioned between said pump 60 and said turbine 22. To do this, the evaporator 80 is connected to a heating circuit which comprises a hot source 92. Said heating circuit is a circuit external to the loop 31. 36.

FIG. 2 illustrates an example of a cooling device which is configured to cool said generator 21. It should be noted that said generator 21 is advantageously an electromagnetic generator. It comprises a stator 24 and a rotor 23, in particular electromagnetic.

Said cooling device comprises a cavity 26 formed in a body intended to form part of said rotor 23, said cavity 26 being intended to receive the working fluid, in particular in the liquid state. Said device is designed to create a film of said working fluid in its liquid state, in said cavity 26, under the effect of an existing centrifugal force when the rotor 23 is driven in a rotational movement with respect to said stator 24.

Said device is also designed to allow evacuation of said fluid, in its gaseous state, towards the outside of the cavity 26, in particular via channels 25 regularly distributed around a longitudinal extension axis of the rotor 23, said axis of the rotor and referenced X in Figure 2. Said cavity 26 comprises in particular a pair of walls 28, 29 arranged to retain the fluid film in the liquid state. In other words, said walls 28, 29 allow the retention of a fluid blade in the liquid state, at the rotor 23 of said generator 21. Said fluid blade is intended to be vaporized and it is the use of the enthalpy of change of state of said fluid which allows the cooling of said generator 21, in particular at the level of said rotor 23.

The walls 28, 29 forming the cavity 26 are flanges formed in the body of the rotor 23, protrusions of material of said rotor, or elements cantilevered on said rotor 23. It should be noted that any protruding element from the surface, particularly smooth, of the rotor 23 and allowing the retention of a fluid film in the liquid state is included in the invention. Thus, the example illustrated and described here is not limiting.

In addition, said walls 28, 29 are advantageously configured so as to allow said fluid portion to escape from said cavity 26 thus delimited only by vaporization, or even overflow. The rotor 23 comprises a body, forming a shaft 23 ', which is primarily represented by its useful part. By "useful part" is meant the part able to participate in the generation of electric current of the electromagnetic generator 21; in other words, the part that carries an electromagnetic element 23. In other words, the portion of the shaft 23 bearing the bearing assemblies which allow the rotational mobility of the rotor 23 is only partially illustrated here.

The electromagnetic generator 21 comprises an electromagnetic element 23 "mounted on the shaft 23 'of the rotor 23. Said electromagnetic element 23" may be a permanent magnet. Said electromagnetic element 23 "is here an electromagnetic winding It may be of any other form, such as a cage rotor, without departing from the scope of the invention.

Moreover, as can be seen in FIG. 2, the cavity 26 is here positioned between the electromagnetic winding 23 "and the shaft 23. It should be noted that said shaft 23 'has a principal direction of longitudinal extension, said main axis, which is referenced X in Figure 2.

In this regard, said cavity 26 extends longitudinally along the electromagnetic winding 23 ", in the direction of said main axis X. More specifically, a bottom 26 'of said cavity 26 is in contact with at least a portion of said winding electromagnetic 23 ". However, the cavity 26 is not constituted here by the single zone provided with the bottom 26 'in contact with the electromagnetic winding 23 "since it also comprises the pair of said walls 28, 29 arranged laterally.

The walls 28, 29 forming the cavity 26 are flanges formed in said shaft 23 ', material protrusions of said shaft 23', or even elements cantilevered on said shaft 23 '. It should be noted that any element protruding from the surface, particularly smooth, of the shaft 23 'and allowing the retention of a fluid film in the liquid state is included in the invention. Thus, the example illustrated and described here is not limiting.

In other words, the walls 28, 29 are advantageously configured so as to allow a fluid portion to remain in the liquid state in the cavity 26 they delimit, in particular under the action of the centrifugal force that the part undergoes. rotating electromagnetic generator 21. Said walls 28, 29 are advantageously configured so as to allow said fluid portion to escape from said cavity 26 thus delimited only by vaporization. Here, the cavity 26 is formed by the zone provided with the bottom 26 'in contact with the electromagnetic winding 23 ", but also by another zone located at an intake block 43 of the liquid in said cavity 26.

Said intake block 43 comprises means for injecting said fluid in the liquid state, called intake rod 41 in the following. This intake rod 41 is fixedly mounted with respect to the stator 24, in particular with respect to the casing 24 "'of said stator 24, it is a pipe for supplying liquid into the cavity 26. The block of emission 40 is therefore composed of a fixed part relative to the stator 24 - said intake rod 41, and a fixed part relative to the rotor 23. Said fixed part relative to the rotor 23 is an annular ring fixed to the rotor 23 and marked 42 In the figure, said annular ring 42 is made of a material that is impervious to liquids, it being this annular ring 42 that forms, here, one of said walls 28 of the cavity 26.

Thus, the cavity 26 is intended to receive a fluid in the liquid state.

As illustrated in FIG. 2, the cooling device is designed to create a film of said fluid in said cavity 26, in particular at the zone provided with said bottom 26 ', in particular under the effect of an existing centrifugal force when the rotor 23 is driven in a rotational movement with respect to the stator 24. Said device further comprises one or more channels for discharging said fluid towards the outside of the cavity 26, said fluid being discharged via the channel (s) In the gaseous state.

In contrast to said discharge channels 25, the cooling device comprises one or more liquid supply channels 25 ', in the liquid state, between said inlet block 43 and the part of the cavity 26 which is formed in the inside of the shaft 23 ', namely the zone provided with the bottom 26' in contact with the electromagnetic winding 23 ".

These supply channels 25 'of fluid in the liquid state are here considered as belonging to the cavity 26 as situated between the two walls 28, 29. Said channels 25, 25 'of fluid supply and discharge are, for example, distributed angularly around the main axis X.

The fluid film created in the cavity 26, as illustrated in FIG. 2, participates in the absorption of the heat produced by the rotation of the rotor 23 inside the stator 24. In fact, its vaporization allows the cooling said generator, in particular at the mobile part 23 of said generator 21. In addition, the small fluid thickness in the liquid state, due to its film configuration, facilitates its rise in temperature and therefore the achievement of its vaporization point.

The film of the fluid in the liquid state remains plated, or stagnant, inside the cavity 26. Said zone provided with the bottom 26 'is configured so that said film has a free surface through which the fluid vaporizes.

The fluid, once vaporized, is discharged through the discharge channels 25 which are gas evacuation channels (see arrows 25 "in Figure 2).

It should be noted that said evacuation channels 25 'are provided closer to the main axis X than the supply channels 25'.

It should also be noted that the fluid, once vaporized, has a density approximately 100 times lower than the density of the same fluid in the liquid state. This advantageously participates in the mechanical evacuation of the vaporized fluid, without external assistance, except for a simple difference in pressure, that is to say without internal means dedicated to the circulation of said fluid.

It should be noted, again, that the heat absorbed by this vaporization is greater than the heat absorbed by the heating of a gas which would circulate in the same place. This also means that the flow of liquid fluid at the intake block 43 may be low, which contributes to increasing the overall efficiency of the electromagnetic generator 21.

Thus, the intake rod 41 is a liquid supply pipe which is not oversized. In addition, it is not necessary to provide a pump for supplying fluid in the liquid state in said intake rod because the flow to be delivered to the cavity 26 remains low.

On the other hand, the injection of liquid fluid by the intake rod 41 may advantageously be enslaved, for example by an overflow sensor located at the level of liquid purges positioned close to the bearings (details not shown here).

Thus, the device of the invention proposes a cooling of the electromagnetic generator 21, this with the aid of a simple arrangement, in particular an arrangement of supply channels 25 'and discharge 25 of a fluid, said channels being carried by the rotor 23 of said generator 21.

It should be noted that the cooling device advantageously comprises a ring 27, positioned on the side of said intake rod 41, said ring 27 being configured to block any gas evolution. Thus, said ring 27 blocks any gas leaks on the side of the intake block 43, especially in case of gas leakage through the supply channel 25 'of fluid in the liquid state. On the other hand, it should be noted that the intake block 43 is advantageously opposed to the exhaust channel 25 of the cooling device, along said main axis X, with respect to said cavity 26.

Spraying said fluid participates in cooling said generator. In addition, the fluid, once vaporized, can be easily evacuated. Said cooling device thus has the advantage of being particularly effective because based on a phase change cooling, which is more with simple structure. It should be noted that the system 10 according to the invention advantageously comprises a sealing device (not shown here) arranged to ensure a seal between said turbine 22 and said generator 21. Said sealing device is positioned between said turbine 22 and said generator 21; it comprises in particular a seal configured to prevent said working fluid, when in the gaseous phase, from circulating from said turbine 22 to said generator 21.

In this case, the extraction of the working fluid in the vapor state, high temperature and low pressure, towards the condenser 50 is between the turbine 22 and the generator 21. It should also be noted that the generator 21 will also comprise a circuit configured to cool the stator 24 by fluid circulation, said fluid entering the liquid state (inlet marked 24 'in FIG. 2) in said cooling circuit and leaving it in the gaseous state (outlet 24 "in FIG. 2), the inlet 24 'and the outlet 24" are made directly in the housing 24 "' of the stator 24.

It should also be noted that the fluid used to cool the electromagnetic generator 21 - at the rotor 23 and / or at the stator 24 - is the same working fluid that circulates within the system 10 according to the invention.

It should also be noted that variant embodiments are of course possible. As already stated, it is also conceivable, in an embodiment not illustrated here, that the quilting of working fluid in the liquid state to supply the cooling device of the generator 21 can be done at other points of the loop 31-36, as its return to the gaseous state in said loop 31 -36. This is all the more appropriate for loops 31-36 implementing the Rankine thermodynamic cycle and in which the elements that compose it are different from those just described here, or arranged differently between them.

The quenching of working fluid in the liquid state will still occur in a part of the loop in which the fluid circulates in the liquid state, at low temperature and at relatively high pressure, while the reinjection of said fluid to the fluid The gaseous state will be in the loop, in a part in which said fluid circulates in the gaseous state and, preferably, at low pressure.

The system 10 of the invention therefore requires a low liquid flow rate to cool the generator 21 of the loop 31 -36 that it includes, especially when this flow rate is compared to that usually used by a cooling loop by heating a liquid, even though this liquid is the same as the working fluid of the thermodynamic system in which it is positioned.

It should also be noted that other embodiments are still possible. In particular, it is also conceivable, in an embodiment not illustrated here, that the rotor rotates around the stator, this without departing from the scope of the invention.

It is also conceivable, in embodiments not illustrated here, that the rotor 23 is driven by any motive force resulting from a transformation of solar, wind, tidal or even nuclear energy, providing a driving torque, either directly or through a turbine.

Claims

claims

1. Thermodynamic system (10), in particular a system (10) implementing a Rankine thermodynamic cycle, comprising a circulation loop (31-36) of a working fluid, said loop (31-36) comprising a means for producing a energy (20), said system (10) further comprising a cooling device of said power generating means (20) and a leg (37,38) configured to supply said cooling device with working fluid from said loop (31-36) and returning said working fluid in said loop (31-36), said cooling device being configured to cool said energy generating means (20) by vaporizing said working fluid therein said production means (20), said working fluid entering the liquid phase in said power generation means

(20), said power generating means (20) comprising a turbine (22) forming part of said loop (31-36), and an electric power generator

(21) coupled to said turbine (22), said turbine (22) being adapted to be driven by the expansion of said working fluid in the gas phase, said cooling device being configured to cool said generator (21), said generator (21 ) being an electromagnetic generator comprising a stator (24) and a rotor (23), said cooling device comprising a cavity (26) formed in a body intended to form part of said rotor (23), said cavity (26) being intended for receiving the working fluid, said device being adapted to create a film of said working fluid in its liquid state, in said cavity (26), under the effect of an existing centrifugal force when the rotor (23) is driven by a rotational movement with respect to said stator (24), said device being further adapted to allow evacuation of said fluid in its gaseous state outwardly of the cavity (26).

2. System (10) according to the preceding claim, wherein the working fluid to be vaporized in said cooling device is fed into said power generation means (20) via a valve, said expansion valve (40) .

3. System (10) according to any one of claims 1 or 2, wherein the working fluid to be vaporized in said cooling device is injected into the power generation means (20) via a nozzle, said injection nozzle (41).

The system (10) of any preceding claim, wherein said loop (31-36) further comprises a condenser (50), said condenser (50) being configured to condense the working fluid when it is in the gas phase.

5. System (10) according to the preceding claim, wherein said loop (31-36) further comprises a pump (60), said pump (60) being adapted to increase the pressure of said working fluid when it is in phase liquid, said pump (60) being positioned downstream of said condenser (50).

6. System (10) according to the preceding claim, wherein the working fluid to be vaporized in the cooling device is stitched in the loop (31-36) downstream of said pump (60).

The system (10) according to any one of claims 5 or 6, wherein said loop (31-36) further comprises a regenerator (70), said regenerator (70) being configured to exchange thermal energy between said working fluid when in the gas phase and said working fluid when in the liquid phase, said regenerator (70) being positioned downstream of said turbine (22) in a portion of the loop (31-36) configured for circulating the working fluid in the gas phase and downstream of said pump (60) in a portion of the loop (31-36) configured for fluid flow in the liquid phase.

The system (10) according to any one of claims 5 to 7, wherein said loop (31-36) further comprises an evaporator (80), said evaporator (80) being configured to evaporate the working fluid when it is in the liquid phase, said evaporator (80) being positioned between said pump (60) and said turbine (22).

The system (10) according to any one of claims 4 to 8, wherein the working fluid vaporized within said energy generating means (20) by said cooling device is released into the loop (31). 36) upstream of said condenser (50).

10. System (10) according to any one of the preceding claims, further comprising a sealing device arranged to ensure a seal between said turbine (22) and said generator (21), said sealing device being positioned between said turbine (22) and said generator (21).

1 1. System (10) according to the preceding claim, wherein said sealing device comprises a seal configured to prevent said working fluid, when in the gaseous phase, from circulating from said turbine (22) to said generator ( 21).

The system (10) of any one of the preceding claims, wherein said cavity (26) comprises a pair of walls (28, 29) arranged to retain the fluid film in the liquid state.

The system (10) according to any one of the preceding claims, wherein said cooling device comprises injection means (41) for said fluid in the liquid state at said cavity (26) and a channel for discharge (25), said injection means (41) of said fluid in the liquid state at said cavity (26) being opposed to the discharge channel (25) relative to said cavity (26).

14. System (10) according to any one of the preceding claims, wherein the rotor (23) comprises a shaft (23 '), formed of said body, and on which is mounted an electromagnetic element (23 "), said shaft ( 23 ') having a main direction of longitudinal extension, said main axis (X), the electromagnetic element (23 ") being an electromagnetic coil, the cavity (26) of the cooling device being positioned between said electromagnetic coil (23" ) and said shaft (23 ').

15. System (10) according to the preceding claim, wherein said cavity (26) extends longitudinally along said electromagnetic coil (23 "), in the direction of said main axis (X), a bottom (26 ') of said cavity (26) being in contact with at least a portion of said electromagnetic coil (23 ").