FR3032520A1 - THERMODYNAMIC SYSTEM - Google Patents

Abstract

The invention relates to a 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 power generating means (20), said system (10) further comprising a cooling device of said power generating means (20) and a leg (37, 38) configured to supply said fluid cooler working from said loop (31-36) and returning said working fluid in said loop (31-36), said cooling device being configured to cool said energy producing means (20) by vaporizing said fluid of said working within said means of production (20), said working fluid entering the liquid phase in said energy producing means (20).

Description

The invention relates to a thermodynamic system, especially a system 5 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 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 using a Rankine thermodynamic cycle, comprising a circulating loop of a working fluid, said loop comprising means for producing energy. According to the invention, 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 vaporizing said working fluid within said production means, said working fluid entering the liquid phase in said production means of energy. 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: said power generation means comprises a turbine forming part of said loop, and an electric energy generator coupled to said turbine; said turbine is intended to be driven by the expansion of said working fluid in the gas phase, said cooling device is configured to cool said generator, said generator is an electromagnetic generator, the working fluid intended to be vaporized in said cooling device is fed into said energy generating means, in particular in said generator, via a valve, called expansion valve, - the working fluid to be vaporized in said cooling device is injected into said cooling means; production of energy, in particular in said generator, via a nozzle, called an injection nozzle, 3032520 3 - said loop further comprises a condenser, - said condenser is configured to condense the working fluid when it is in the gas phase, - said loop further comprises a pump, - said pump is able to increase the pressure of said working fluid when in the liquid phase, - said pump is positioned downstream of said condenser, - the working fluid 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 gas phase and said working fluid when it is in the liquid phase, - said regenerator is positioned downstream of said turbine in a portion 15 of the loop configured for the circulation of the working fluid in the gas phase and downstream of said pump in a portion of the loop configured for the liquid-phase fluid recovery, - 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 fluid vaporized within 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 to provide 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 fluid when in the gaseous phase, to flow from said turbine to said generator, 3032520 4 - said generator is an electromagnetic generator comprising a stator and a rotor, said cooling device comprises 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 designed 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 said fluid in its gaseous state to the outside of the cavity. 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 discharge channel with respect to said cavity. The invention will be better understood, and other objects, details, features, and advantages thereof will become more clearly apparent from the following detailed explanatory description of at least one embodiment of the given invention. by way of a purely illustrative and nonlimiting 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, FIG. schematic section, partial, 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 power generation means 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 fluid working in said loop 31-36, after cooling said generator 21. The return of said working fluid in said loop 31-36 is via a portion of the branch referenced 38 in Figure 1. Said cooling device is configured from in order 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 relaxes, 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 is circulated through 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 exits in the form of steam, high temperature and high pressure, and then is directed towards 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 feed the cooling device with working fluid from said loop 31-36. It should be noted, however, that said cooling device can 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 part of the branch 38 said working fluid is returned to said loop 31-36, after cooling. According to the invention, the cooling is carried out by vaporizing 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 in the process. the loop 31-36 where the fluid circulates 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 case of presence of a 25 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 in fact a bypass branch of a part of the working fluid, between the outlet of the pump 60 and said generator 21. The working fluid intended to be vaporized in said cooling device can be injected into said generator 22 via a nozzle 41, called injection nozzle 41, shown in Figure 2.

In the example illustrated, 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 level of the condenser 50, in particular at the pressure of the condenser 50. To do this, the condenser 50 is connected 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 the 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 fluid when 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 exemplary 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 rotated relative 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 The cavity 26 includes 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 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 element making protrusion 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 herein 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. Said device further comprises an injection means, or injection nozzle 41, of said fluid in the liquid state at said cavity 26. Said injection nozzle 41 is positioned with respect to said cavity 26, on the side opposite to said discharge channels 25.

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 sealing gasket 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 from the state of vapor, high temperature and low pressure, towards the condenser 50 is located between the turbine 22 and the generator 21.

It should also be noted that the cooling device advantageously comprises a ring 27 positioned on the side of the injection nozzle 41, said ring 27 being configured to block any gas evolution, in particular by blocking any gas leakage towards said nozzle. injection 41.

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 in The inlet 24 'and the outlet 24 "are made directly into a housing of the stator 24. It should also be noted that the fluid used to cool the generator is in the gaseous state (outlet 24" in FIG. electromagnetic 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 alternative embodiments are of course possible. As already stated, it is also conceivable, in an exemplary embodiment not illustrated here, that the stitching of working fluid in the liquid state to feed the cooling device of the generator 21 can be done at other points of the 30 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 which compose it are different from those which have just been described here, or even arranged differently between them.

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

Claims (15)

REVENDICATIONS1. A thermodynamic system (10), in particular a system (10) employing a Rankine thermodynamic cycle, comprising a circulating loop (31-36) of a working fluid, said loop (31-36) comprising a production means 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 energy generating means (20). Thermodynamic system (10) according to the preceding claim, wherein said energy generating means (20) comprises 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 intended to be driven by the expansion of said working fluid in the gas phase, said cooling device being configured to cool said generator (21). The system (10) according to any one of the preceding claims, wherein the working fluid to be vaporized in said cooling device is fed into said power generating means (20) via a valve, called relaxation (40). 4. System (10) according to any one of the preceding claims, wherein the working fluid to be vaporized in said cooling device is injected into the power generation means (20) via a nozzle, called nozzle d injection (41). 3032520 12 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 5 in the gas phase. 6. System (10) according to the preceding claim, wherein said loop (3136) further comprises a pump (60), said pump (60) being adapted to increase the pressure of said working fluid when in the liquid phase, Said pump (60) being positioned downstream of said condenser (50). 7. 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). 15 The system (10) according to any one of claims 6 or 7, 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 the circulation of the working fluid in the gas phase and downstream of said pump (60) in a portion of the loop (31-36) configured for the circulation of the fluid in the liquid phase. 25 The system (10) according to any one of claims 6 to 8, 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 5 to 9, 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). 11. System (10) according to claim 2, further comprising a sealing device 5 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). 12. System (10) according to the preceding claim, wherein said sealing device 10 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 claim 2, wherein said generator (21) is 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 adapted to receive 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 rotated relative to said stator (24), said device being further adapted to allow evacuation of said fluid in its gaseous state to the outside the cavity (26). 25 14. System (10) according to the preceding claim, wherein said cavity (26) comprises a pair of walls (28, 29) arranged to retain the fluid film in the liquid state. 15. System (10) according to any one of claims 13 or 14, wherein said cooling device comprises means (41) for injecting said fluid in the liquid state at said cavity (26) and a discharge channel (25), said injection means (41) of said fluid in the liquid state at said cavity (26) being opposite the discharge channel (25), with respect to said cavity (26) .