EP3438422A1 - Device for regulating the fluid load circulating in a system based on a rankine cycle - Google Patents

Abstract

The system comprises a device for regulating the fluidic charge circulating in the fluid circuit configured to operate in a closed circuit with the fluid circuit and maintain saturation conditions in the reservoir (105) so that the reservoir (105) contains the fluid working simultaneously in the liquid state (3) and in the gaseous state (4), the regulating device comprising thermal energy supply elements in the reservoir (105) intended to increase the reservoir pressure and to induce injecting the working fluid from the reservoir into the fluid circuit and reservoir energy-removing elements (105) for decreasing the pressure of the reservoir and inducing the suction to the reservoir (105) of the working fluid out of the reservoir; fluidic circuit.

Description

TECHNICAL FIELD OF THE INVENTION

The present invention relates to systems for producing electrical or mechanical energy.

It finds for advantageous application the systems of production of energy of small power, calling on a thermodynamic cycle of Rankine. It will apply, for example, to the production of energy from low-temperature heat discharges produced by factories, particularly in the processing industry (metallurgy, chemistry, paper mills), by thermal engines of vehicles or from heat from systems recovering solar energy or from biomass.

The present invention will find an application particularly for the thermal management of embedded systems, small power or having significant power variations over time.

STATE OF THE ART

There are many solutions for producing electricity or mechanical energy from a heat source.

Known solutions include generation machines based on a Rankine cycle. The Rankine cycles are all based on transformations successively comprising: the pumping of a working fluid in liquid form, the creation of steam and its possible overheating, the relaxation of the steam to generate a movement and the condensation of the vapor. The working fluid may be selected from water, carbon dioxide, ammonia or an organic fluid or a mixture of these components. In the latter case, we speak of organic Rankine cycle. The majority of thermal power generation systems are based on the use of such cycles.

• une pompe permettant la mise en circulation du fluide et la remontée de sa pression ;
• un échangeur chaud exploitant la source de chaleur disponible à valoriser ;
• un expanseur ou organe de détente transformant la variation d'enthalpie du fluide en énergie mécanique, puis en énergie électrique en présence d'une génératrice également désignée alternateur ;
• un échangeur froid permettant la condensation de la vapeur restante après détente.

A machine based on a Rankine cycle is, in known manner, made up of four main organs, namely:

• a pump for circulating the fluid and raising its pressure;
• a hot heat exchanger exploiting the available heat source to be upgraded;
• an expander or expansion device transforming the enthalpy change of the fluid into mechanical energy, then into electrical energy in the presence of a generator also designated alternator;
• a cold exchanger allowing the condensation of the remaining vapor after expansion.

It is on this type of thermodynamic cycle that the majority of nuclear power plants, coal-fired power plants, or heavy-fuel thermal power plants are based in order to produce high power. For these applications, the hot springs have a very high power and temperature.

The processing industries, for example metallurgy, chemistry or paper mills, generate low-temperature thermal discharges, that is to say thermal discharges whose temperature is most often less than 200 ° C, or even lower at 150 ° C. Systems based on a Rankine cycle would theoretically produce electrical or mechanical energy from these heat discharges. However, the powers that could be produced would then be relatively low, typically of the order of a few kilowatts to a hundred kilowatts for thermal discharges below one megawatt, because of the low thermodynamic efficiency.

At these levels of temperature and power, there is currently no truly satisfactory valuation solution, because of the necessary investments and conversion efficiencies that are not considered sufficient.

These low temperature thermal discharges are then in practice little exploited and valued. It is the same for the heat produced by the thermal engines of land or water vehicles.

In order to maximize the net power and efficiency of a Rankine machine, it is useful to lower the condensing pressure as much as possible. However, to ensure the proper functioning of the pumping member, the fluid must enter the pump in a sub-cooled liquid state.

Subcooling, which is the difference between the pump inlet temperature and the fluid saturation temperature, is called subcooling. Too much subcooling indicates that there is too much liquid in the condenser, which leads to a degradation of the performance of the Rankine machine by increasing the condensing pressure. Inversely, insufficient subcooling leads to a risk of cavitation at the pump inlet and therefore a degradation of the performances of the Rankine machine as well as accelerated wear of the pump.

Cavitation occurs when the pumped liquid vaporizes at low pressure. This occurs because of insufficient pressure at the pump inlet relative to the fluid saturation pressure, in other words, when there is an NPSHa (positive net Suction Head available), or margin of cavitation, insufficient. When cavitation appears, vapor bubbles are created at low pressure. While the liquid flows from the suction of the pump to its outlet, the bubbles implode, creating shock waves that attack the pump and cause vibrations in the pump, a decline in performance and mechanical damage that can lead to premature wear or even the complete destruction of the pump at different levels

However, the temperature at the pump inlet is determined and limited by the cold source and the heat exchange at the condenser. The cavitation margin or the subcooling are therefore directly related to the condensation pressure.

One solution is to regulate the subcooling at the pump inlet as well as the condensing pressure by managing the circulating fluid load in the plant. In the document EP 2,933,444 A1 , the closed circuit operating in a Rankine cycle comprises a closed reservoir containing the fluid in the liquid state stitched on the pump line connecting the condenser to the pump. The tank is connected to a pressure regulator device for pressurizing the tank by a regulator regulator injecting a gas type air or nitrogen and a depressurization of the tank by a valve for discharging a portion of the gaseous fluid out of the tank. The control device therefore uses an external gas and a control unit receiving the information from various sensors to control the expander and the valve.

In this way, at each instant, the fluid at the pump inlet has a sufficient level of subcooling with the absence of fluid in the vapor phase thus limiting the risk of cavitation.

This type of device still requires improvements to allow including implementation in embedded systems.

There is therefore a need to push the simplification of electrical or mechanical power generation devices to facilitate their use in various applications.

SUMMARY OF THE INVENTION

• au moins un premier échangeur de chaleur configuré pour être couplé thermiquement à au moins une première source de chaleur, également dénommé évaporateur,
• un expanseur dont une entrée est fluidiquement raccordée à une sortie du premier échangeur,
• un deuxième échangeur de chaleur configuré pour être couplé thermiquement à une deuxième source de chaleur plus froide que la première source de chaleur, également dénommé condenseur,
• au moins une pompe configurée pour mettre en mouvement le fluide de travail dans le circuit fluidique,
• au moins un réservoir, recevant avantageusement le fluide de travail, et agencé entre le deuxième échangeur et la pompe sur une conduite de piquage.

To achieve this objective, one aspect of the present invention relates to an electrical or mechanical power generation system comprising a fluid circuit configured to receive a circulating working fluid and comprising a plurality of members to be traversed by the working fluid. and among which:

• at least one first heat exchanger configured to be thermally coupled to at least one first heat source, also referred to as an evaporator,
• an expander whose input is fluidly connected to an output of the first exchanger,
• a second heat exchanger configured to be thermally coupled to a second heat source cooler than the first heat source, also referred to as a condenser,
• at least one pump configured to move the working fluid in the fluid circuit,
• at least one reservoir, advantageously receiving the working fluid, and arranged between the second exchanger and the pump on a branch pipe.

The fluid circuit of the system being configured so that the working fluid passes successively through at least the pump, the first exchanger, the expander and the second heat exchanger, then again the pump. The system typically comprises a device for regulating the fluidic charge circulating in the fluidic circuit comprising advantageously thermal energy supply elements in the reservoir, advantageously intended to increase the pressure of the reservoir and inject working fluid from the reservoir into the fluidic circuit, and energy removal elements of the reservoir, advantageously intended to reduce the tank pressure and draw working fluid from the fluid circuit to the tank. The regulating device is advantageously configured to operate in a closed circuit with the fluid circuit and advantageously to maintain saturation conditions in the reservoir so that the reservoir contains the working fluid simultaneously in the liquid state and in the gaseous state.

The device for regulating the fluidic charge makes it possible, by an energy supply in the reservoir, to expand the working fluid (liquid and vapor phase) present in the reservoir, which has the consequence of pressurizing the reservoir and injecting a fraction of the present fluid. in the tank in the fluid circuit. Conversely, a decrease in reservoir energy tends to increase the average density in the tank, reduce its pressure and suck up a fraction of the circulating fluid in the fluidic circuit.

The system according to the invention makes it possible not to use an external gas source to control the pressure in the tank. Only the working fluid is used thus limiting the risk of contamination of the working fluid. The compactness of the system is improved by limiting the necessary components, the system does not need compressor or pressure bottle. The cost of implementation and maintenance is also reduced.

Advantageously, the reservoir is connected directly, continuously, by the tapping pipe to the fluid circuit. Preferably, the reservoir does not comprise a mechanical element, in particular arranged on the tapping pipe, controlling the injection or suction of the working fluid in the fluid circuit.

The system according to the invention thus has a low energy consumption and increased operational simplicity.

Advantageously, the system according to the invention comprises, as elements for supplying thermal energy, at least one heating rod. immersed in the reservoir, or a partial coupling with the first heat source, or an injection module, in the reservoir, working fluid taken at the outlet of the first exchanger.

Advantageously, the system according to the invention comprises, as energy-removal elements, a module for ejecting the fluid in the gaseous state, out of the tank, towards the inlet of the second exchanger or an injection module, in the reservoir, working fluid taken at the outlet of the pump, or a partial coupling with the second heat source.

According to an independent variant, the invention relates to a self-regulating module for the fluidic charge circulating in a fluid circuit of an electrical or mechanical energy production system operating according to a Rankine cycle. The self-regulation module is configured to regulate the pressure of a tank stitched on the fluid circuit and receiving the working fluid. The self-regulation module is preferably mechanically operated, intended to regulate the pressurization and the depressurization of the reservoir. The self-regulation module makes it possible to automatically and preferably mechanically manage only the pressurization and depressurization of the reservoir, that is to say the injection or removal of working fluid in the fluid circuit.

The present invention thus makes it possible to control the subcooling and limit the risks of cavitation by a closed circuit system, that is to say not requiring external fluid and advantageously self-regulating by a purely mechanical operation simplifying the system and its operation.

The system is thus efficient and easily transposable into embedded systems.

• une étape de montée en pression du fluide de travail au travers de la pompe,
• une étape de chauffage du fluide de travail au travers du premier échangeur de chaleur,
• une étape de détente du fluide de travail issu du premier échangeur au travers de l'expanseur,
• une étape de refroidissement du fluide de travail au travers du deuxième échangeur de chaleur,

caractérisé en ce qu'il comprend une étape de maintien de conditions saturantes dans le réservoir pour maintenir le fluide de travail simultanément sous deux états gazeux et liquide dans le réservoir par une étape d'apport d'énergie thermique dans le réservoir comprenant l'augmentation de la pression dans le réservoir et l'ajout de fluide de travail dans le circuit fluidique par injection depuis le réservoir, ou alternativement une étape de retrait d'énergie hors du réservoir comprenant la diminution de la pression dans le réservoir et le retrait de fluide de travail du circuit fluidique par aspiration vers le réservoir.Another aspect of the present invention relates to the method of regulating the fluidic charge circulating in the fluid circuit of a power generation system according to any one of the preceding claims comprising the following steps:

• a step of increasing the pressure of the working fluid through the pump,
• a step of heating the working fluid through the first heat exchanger,
• a step of relaxing the working fluid from the first exchanger through the expander,
• a step of cooling the working fluid through the second heat exchanger,

characterized in that it comprises a step of maintaining saturating conditions in the reservoir to maintain the working fluid simultaneously in two gaseous and liquid states in the reservoir by a step of supplying thermal energy into the reservoir comprising the increase of the pressure in the reservoir and the addition of working fluid in the fluidic circuit by injection from the reservoir, or alternatively a step of withdrawing energy from the reservoir comprising the reduction of the pressure in the reservoir and the withdrawal of fluid working fluidic circuit by suction to the tank.

In a particularly advantageous manner, the invention makes it possible to make the use of heat rejects at low temperature profitable, while requiring little energetic means. In addition, the present invention provides a simplified system, inexpensive, low energy consumption, while having improved energy efficiency without overburdening the pump or increase the cost and complexity of the system.

BRIEF DESCRIPTION OF THE FIGURES

• La FIGURE 1 illustre un système selon l'invention fonctionnant suivant un cycle de Rankine.
• Les FIGURES 2 à 4 sont des schémas illustrant le réservoir dans un système selon l'invention. La FIGURE 2 correspond à une situation à l'équilibre, la FIGURE 3 correspond à l'injection de fluide de travail dans le circuit fluidique,
• La FIGURE 4 correspond à l'aspiration de fluide de travail du circuit fluidique vers le réservoir.
• Les FIGURES 5 à 10 illustrent différents modes de réalisations du dispositif de régulation de la charge fluidique en circulation dans le circuit fluidique. Les FIGURES 5 à 7 correspondent à des modes de réalisation d'éléments d'apport d'énergie thermique dans le réservoir tandis que les FIGURES 8 à 10 correspondent à des modes de réalisation d'éléments de retrait d'énergie du réservoir.
• Les FIGURES 11 et 12 illustrent une partie du système selon un mode de réalisation intégrant un module d'autorégulation. La FIGURE 11 correspond à un premier mode de réalisation, la FIGURE 12 correspond à un deuxième mode de réalisation.
• La FIGURE 13 est une vue en coupe d'un boitier du module d'autorégulation comprenant une soupape et un détendeur.
• La FIGURE 14 représente les différents cas d'autorégulation de la charge fluidique en circulation dans le circuit fluidique.

The objects, objects, as well as the features and advantages of the invention will become more apparent from the detailed description of an embodiment thereof which is illustrated by the following accompanying drawings in which:

• The FIGURE 1 illustrates a system according to the invention operating according to a Rankine cycle.
• The FIGURES 2-4 are diagrams illustrating the reservoir in a system according to the invention. The FIGURE 2 corresponds to a situation at equilibrium, the FIGURE 3 corresponds to the injection of working fluid into the fluid circuit,
• The FIGURE 4 corresponds to the suction of working fluid from the fluid circuit to the reservoir.
• The FIGURES 5 to 10 illustrate different embodiments of the device for regulating the fluidic charge circulating in the fluidic circuit. The FIGURES 5-7 corresponding to embodiments of thermal energy supply elements in the reservoir while the FIGURES 8 to 10 correspond to embodiments of energy removal elements of the reservoir.
• The FIGURES 11 and 12 illustrate a part of the system according to an embodiment integrating a self-regulation module. The FIGURE 11 corresponds to a first embodiment, the FIGURE 12 corresponds to a second embodiment.
• The FIGURE 13 is a sectional view of a housing of the self-regulating module comprising a valve and a pressure reducer.
• The FIGURE 14 represents the different cases of self-regulation of the fluidic charge circulating in the fluidic circuit.

The drawings are given by way of example and are not limiting of the invention. They constitute schematic representations of principle intended to facilitate the understanding of the invention and are not necessarily at the scale of practical applications.

DETAILED DESCRIPTION OF THE INVENTION

• ∘ Suivant un mode de réalisation, le réservoir 105 est directement raccordé fluidiquement à la conduite de piquage 114 qui est elle-même directement fluidiquement raccordée au circuit fluidique entre le deuxième échangeur 102 et la pompe 104.
• ∘ Suivant un mode de réalisation, le système ne comprend pas d'élément de régulation entre le réservoir 105 et le circuit fluidique.
  Ces dispositions présentent l'avantage d'avoir un circuit simplifié et une réactivité de régulation améliorée.
• ∘ Suivant un mode de réalisation, le fluide de travail est un fluide organique.
• ∘ Suivant un mode de réalisation, le fluide de travail est un fluide inorganique.
• ∘ Suivant un mode de réalisation, le dispositif de régulation ne comprend pas de fluide autre que le fluide de travail. Le dispositif de régulation ne fait appel qu'au fluide de travail présent dans le circuit fluidique et dans le réservoir 105.
• ∘ Suivant un mode de réalisation, les éléments d'apport d'énergie thermique comprennent au moins une canne chauffante 5 plongeant dans le réservoir 105.
  La présence de canne de chauffage 5 est une solution qui, malgré une forte consommation d'énergie, permet une bonne régulation et un faible coût d'installation.
• ∘ Suivant un mode de réalisation, les éléments d'apport d'énergie thermique comprennent un module d'injection, dans le réservoir 105, de fluide de travail prélevé à la sortie 11 du premier échangeur 101.
  Le fluide de travail prélevé à la sortie 11 du premier échangeur 101, qui est avantageusement un évaporateur, est à haute température et haute pression. Son injection dans le réservoir 105 augmente la pression du réservoir Pr et pousse le fluide de travail stocké dans le réservoir 105 vers le circuit fluidique. Cette solution a l'avantage d'une grande simplicité sans risque de contamination par un autre fluide et une faible consommation énergétique.
• ∘ Suivant un mode de réalisation, les éléments d'apport d'énergie thermique comprennent un couplage, au moins partiel, du réservoir 105 avec la première source de chaleur 1.
  La première source de chaleur 1 permet de réchauffer le fluide de travail contenu dans le réservoir 105 augmentant ainsi la pression du réservoir Pr et pousse le fluide de travail stocké dans le réservoir 105 vers le circuit fluidique.
• ∘ Suivant un mode de réalisation, les éléments de retrait d'énergie comprennent un module d'éjection, hors du réservoir 105, du fluide de travail à l'état gazeux 4 en direction de l'entrée 21 du deuxième échangeur 102.
  Le fluide de travail à l'état gazeux 4 est éjecté dans le circuit fluidique au niveau de l'entrée 21 du deuxième échangeur 102, qui est avantageusement un condenseur. L'évacuation du fluide à l'état gazeux 4 du réservoir 105 diminue la pression du réservoir Pr et aspire le fluide de travail du circuit fluidique vers le réservoir 105.
  Avantageusement, le deuxième échangeur 102 est agencé à une hauteur supérieure du réservoir 105 de sorte que le déplacement de fluide gazeux ne se fasse qu'en direction du deuxième échangeur 102 par différence de pression hydrostatique. Cette solution présente un fort potentiel de refroidissement.
• ∘ Suivant un mode de réalisation, les éléments de retrait d'énergie comprennent un module d'injection, dans le réservoir 105, de fluide de travail prélevé à la sortie 42 de la pompe 104.
  Le fluide de travail prélevé à la sortie 42 de la pompe 104, c'est-à-dire après la sortie 22 du deuxième échangeur 102, qui est avantageusement un condenseur, est à basse température et basse pression. Son injection dans le réservoir 105 diminue la pression du réservoir et aspire le fluide de travail du circuit fluidique vers le réservoir 105.
• ∘ Suivant un mode de réalisation, les éléments de retrait d'énergie comprennent un couplage au moins partiel du réservoir 105 avec la deuxième source de chaleur 2.
  La deuxième source de chaleur 2 permet de refroidir le fluide de travail contenu dans le réservoir 105 diminuant ainsi la pression du réservoir Pr et aspirant le fluide de travail du circuit fluidique vers le réservoir 105.
• ∘ Suivant un mode de réalisation, les éléments d'apport d'énergie thermique comprennent un module d'injection, dans le réservoir 105, de fluide de travail prélevé à la sortie 12 du premier échangeur 101 et les éléments de retrait d'énergie comprennent un module d'éjection du fluide à l'état gazeux 4, hors du réservoir 105, en direction de l'entrée du deuxième échangeur 21 ou un module d'injection, dans le réservoir 105, de fluide de travail prélevé à la sortie de la pompe 104.
• ∘ Suivant un mode de réalisation, le système comprend un module d'autorégulation 200 à fonctionnement mécanique destiné à réguler la pressurisation et la dépressurisation du réservoir 105.
  Le système régule automatiquement la pression dans le réservoir 105 de sorte à réguler la charge fluidique du circuit. Ces régulations se font de manière mécanique, c'est-à-dire que le module d'autorégulation 200 ne comprend que des éléments mécaniques.
• ∘ Suivant un mode de réalisation, le module d'autorégulation 200 comprend un détendeur 201 compensé couplé à une soupape 203 compensée.
• ∘ Suivant un mode de réalisation, le module d'autorégulation 200 comprend un boitier 205 recevant un détendeur 201 associé à un ressort de détendeur 202 et une soupape 203 associée à un ressort de soupape 204.
  Ce module d'autorégulation 200 est un élément avantageusement unitaire, monobloc, avec une compacité permettant son intégration dans de nombreuses installations et notamment dans les systèmes embarqués.
• ∘ Suivant un mode de réalisation, le boitier 205 comprend une première ouverture 206 en liaison fluidique avec le réservoir 105 de sorte à être soumise à la pression du réservoir Pr.
  La première ouverture 206 est en communication fluidique avec le réservoir 105, avantageusement raccordée directement c'est-à-dire sans élément autre qu'une conduite.
• ∘ Suivant un mode de réalisation, le boitier 205 comprend une deuxième ouverture 207 en liaison fluidique avec un module de production de pression de contrôle de sorte à être soumise à une pression contrôlée Pc.
  La deuxième ouverture 207 est en communication fluidique avec un module gérant une pression contrôlée, avantageusement raccordée directement c'est-à-dire sans élément autre qu'une conduite.
• ∘ Suivant un mode de réalisation, le boitier 205 comprend une troisième ouverture 208 d'injection de fluide de travail, dans le réservoir 105, en provenance de la sortie 12 du premier échangeur 101.
  La troisième ouverture 208 est en communication fluidique avec la sortie 12 du premier échangeur 101, avantageusement raccordée directement c'est-à-dire sans élément autre qu'une conduite.
• ∘ Suivant un mode de réalisation, le boitier 205 comprend une quatrième ouverture 209 d'injection, dans le réservoir 105, de fluide de travail en provenance de la sortie 42 de la pompe 104 ou d'éjection de fluide de travail à l'état gazeux 4, hors du réservoir 105, vers l'entrée 21 du deuxième échangeur 102.
  La quatrième ouverture 208 est en communication fluidique avec la sortie 42 de la pompe 104 ou l'entrée 21 du deuxième échangeur 102, avantageusement directe c'est-à-dire sans élément autre qu'une conduite.
• ∘ Suivant un mode de réalisation, la pression de contrôle Pc est égale à la pression de saturation du fluide en entrée 41 de pompe 104, avantageusement pendant l'opération, le fonctionnement, du système.
• ∘ Suivant un mode de réalisation, le ressort de soupape 204 présente une raideur Ks supérieure à celle Kd du ressort de détendeur 202.
• ∘ Suivant un mode de réalisation, le module d'autorégulation 200 est configuré pour être à l'équilibre, avec le détendeur 201 fermé et la soupape 203 fermée, lorsque la pression du réservoir Pr est à la fois supérieure à la somme de la pression de contrôle Pc et de la raideur Kd du ressort du détendeur 202 et inférieure à la somme de la pression de contrôle Pc et de la raideur Ks du ressort de la soupape 204. De cette manière, la cavitation en entrée de pompe est quasi nulle et le sous-refroidissement non excessif.
• ∘ Suivant un mode de réalisation, le module d'autorégulation 200 est configuré pour que l'ouverture de la soupape 203 mette en connexion fluidique le réservoir 105 et l'entrée 21 du deuxième échangeur 102 ou la sortie 42 de la pompe 104 par la quatrième ouverture 209.
• ∘ Suivant un mode de réalisation, le module d'autorégulation 200 est configuré pour que l'ouverture du détendeur 201 mette en connexion fluidique le réservoir 105 et la sortie 12 du premier échangeur 101 par la troisième ouverture 208.
• ∘ Suivant un mode de réalisation, le module de production de pression de contrôle comprend un ballon 210 rempli de fluide de travail connecté fluidiquement à la deuxième ouverture 207 du boitier 205, le ballon 210 étant agencé pour plonger dans le fluide de travail du circuit fluidique en sortie 22 du deuxième échangeur 102 de sorte que la température du fluide contenu dans le ballon 210 soit identique à celle du fluide de travail du circuit fluidique en entrée 41 de pompe 104. De cette manière, la pression du fluide contenu dans le ballon 210, à saturation, est identique à la pression de saturation du fluide de travail du circuit fluidique en entrée 41 de pompe 104.
• ∘ Suivant un mode de réalisation, le module de production de pression de contrôle comprend une source de gaz à pression régulée en connexion fluidique avec la deuxième ouverture 207 du boitier 205, des capteurs de pression et/ou de température entrée 41 de pompe 104 et des moyens de régulations de la pression de la source de gaz de sorte à définir une pression de contrôle Pc.
• ∘ Suivant un mode de réalisation, le procédé comprend une étape d'autorégulation destinée à réguler la pressurisation et la dépressurisation du réservoir 105 de sorte qu'à l'équilibre le détendeur 201 et la soupape 203 soient fermés lorsque la pression du réservoir Pr est à la fois supérieure à la somme de la pression de contrôle Pc et de la raideur Kd du ressort du détendeur 202 et inférieure à la somme de la pression de contrôle Pc et de la raideur Ks du ressort de la soupape 204.
• ∘ Suivant un mode de réalisation, le procédé est tel qu'il comprend lorsque la pression du réservoir Pr est supérieure à la somme de la pression de contrôle Pc et de la raideur Ks du ressort de la soupape 204, l'ouverture de la soupape 203 mettant en connexion fluidique le réservoir 105 et l'entrée 21 du deuxième échangeur 102 ou la sortie 42 de la pompe 104 par la quatrième ouverture 209 de sorte à diminuer la pression du réservoir Pr et retirer par aspiration vers le réservoir 105, du fluide de travail du circuit fluidique.
• ∘ Suivant un mode de réalisation, le procédé est tel qu'il comprend lorsque la pression du réservoir Pr est inférieure à la pression de contrôle Pc additionnée à la raideur Kd du ressort du détendeur 202, l'ouverture du détendeur mettant en connexion fluidique le réservoir 105 et la sortie 12 du premier échangeur 101 par la troisième ouverture 208 de sorte à augmenter la pression du réservoir Pr, et ajouter par injection depuis le réservoir 105 du fluide de travail dans le circuit fluidique.
• ∘ La sortie 42 de pompe 104 est directement raccordée à l'entrée 11 du premier échangeur 101.
• ∘ La sortie 12 du premier échangeur 101 est directement raccordée à l'entrée 31 de l'expanseur 103.
• ∘ La sortie 32 de l'expanseur 103 est directement raccordée à entrée 21 du deuxième échangeur 102.
• ∘ La sortie 22 du deuxième échangeur 102 est directement raccordée à la pompe 104.
• ∘ Le réservoir 105 est directement raccordé au circuit fluidique entre la sortie 22 du deuxième échangeur 102 et l'entrée 41 de pompe 104.
• ∘ Le circuit fluidique est hermétique, préférentiellement le système est hermétique. Ceci permet avantageusement de limiter les risques pour l'environnement et pour l'homme lorsqu'ils sont toxiques.

Before starting a detailed review of embodiments of the invention, are set forth below optional features that may optionally be used in combination or alternatively:

• According to one embodiment, the reservoir 105 is directly fluidly connected to the sewing pipe 114 which is itself directly fluidically connected to the fluid circuit between the second exchanger 102 and the pump 104.
• According to one embodiment, the system does not comprise a regulating element between the reservoir 105 and the fluid circuit.
  These provisions have the advantage of having a simplified circuit and an improved control reactivity.
• According to one embodiment, the working fluid is an organic fluid.
• According to one embodiment, the working fluid is an inorganic fluid.
• According to one embodiment, the regulating device does not comprise any fluid other than the working fluid. The regulating device uses only the working fluid present in the fluid circuit and in the tank 105.
• According to one embodiment, the elements for supplying thermal energy comprise at least one heating rod 5 immersed in the reservoir 105.
  The presence of heating rod 5 is a solution which, despite high energy consumption, allows good regulation and low installation cost.
• According to one embodiment, the thermal energy input elements comprise an injection module, in the reservoir 105, of working fluid taken at the outlet 11 of the first exchanger 101.
  The working fluid taken at the outlet 11 of the first exchanger 101, which is advantageously an evaporator, is at high temperature and high pressure. Its injection into the reservoir 105 increases the pressure of the reservoir Pr and pushes the working fluid stored in the reservoir 105 to the fluid circuit. This solution has the advantage of great simplicity without risk of contamination by another fluid and low energy consumption.
• According to one embodiment, the thermal energy supply elements comprise a coupling, at least partially, of the tank 105 with the first heat source 1.
  The first source of heat 1 makes it possible to heat up the working fluid contained in the tank 105, thus increasing the pressure of the tank Pr and pushing the working fluid stored in the tank 105 towards the fluidic circuit.
• According to one embodiment, the energy removal elements comprise an ejection module, out of the tank 105, of the working fluid in the gaseous state 4 towards the inlet 21 of the second exchanger 102.
  The working fluid in the gaseous state 4 is ejected into the fluid circuit at the inlet 21 of the second exchanger 102, which is advantageously a condenser. The evacuation of the fluid in the gaseous state 4 of the tank 105 decreases the pressure of the tank Pr and draws the working fluid from the fluidic circuit towards the tank 105.
  Advantageously, the second exchanger 102 is arranged at an upper height of the reservoir 105 so that the gaseous fluid displacement is only in the direction of the second exchanger 102 by hydrostatic pressure difference. This solution has a high cooling potential.
• According to one embodiment, the energy removal elements comprise an injection module, in the reservoir 105, of working fluid taken at the outlet 42 of the pump 104.
  The working fluid taken at the outlet 42 of the pump 104, that is to say after the outlet 22 of the second exchanger 102, which is advantageously a condenser, is at low temperature and low pressure. Its injection into the reservoir 105 decreases the reservoir pressure and draws the working fluid from the fluid circuit to the reservoir 105.
• According to one embodiment, the energy removal elements comprise at least partial coupling of the tank 105 with the second heat source 2.
  The second source of heat 2 makes it possible to cool the working fluid contained in the tank 105 thus reducing the pressure of the reservoir Pr and sucking the working fluid from the fluid circuit to the reservoir 105.
• According to one embodiment, the thermal energy input elements comprise an injection module, in the reservoir 105, working fluid taken at the outlet 12 of the first exchanger 101 and the energy removal elements comprise a module for ejecting the fluid in the gaseous state 4, out of the tank 105, in the direction of the inlet of the second exchanger 21 or an injection module, into the reservoir 105, working fluid taken at the outlet of the pump 104.
• According to one embodiment, the system comprises a self-regulating module 200 with mechanical operation intended to regulate the pressurization and the depressurization of the reservoir 105.
  The system automatically regulates the pressure in the reservoir 105 so as to regulate the fluidic load of the circuit. These regulations are made mechanically, that is to say that the self-regulation module 200 comprises only mechanical elements.
• According to one embodiment, the self-regulation module 200 comprises a compensated pressure reducer 201 coupled to a compensated valve 203.
• According to one embodiment, the self-regulation module 200 comprises a housing 205 receiving a pressure reducer 201 associated with an expansion spring 202 and a valve 203 associated with a valve spring 204.
  This self-regulation module 200 is an advantageously unitary element, monobloc, with compactness for its integration in many facilities and in particular in embedded systems.
• According to one embodiment, the housing 205 comprises a first opening 206 in fluid connection with the reservoir 105 so as to be subjected to the pressure of the reservoir Pr.
  The first opening 206 is in fluid communication with the reservoir 105, advantageously connected directly, that is to say without any element other than a pipe.
• According to one embodiment, the housing 205 comprises a second opening 207 in fluid connection with a control pressure production module so as to be subjected to a controlled pressure Pc.
  The second opening 207 is in fluid communication with a module managing a controlled pressure, advantageously connected directly, that is to say without any element other than a pipe.
• According to one embodiment, the housing 205 comprises a third working fluid injection opening 208, in the tank 105, from the outlet 12 of the first exchanger 101.
  The third opening 208 is in fluid communication with the outlet 12 of the first exchanger 101, advantageously directly connected, that is to say without any element other than a pipe.
• According to one embodiment, the housing 205 comprises a fourth opening 209 for injection into the reservoir 105 of working fluid from the outlet 42 of the pump 104 or ejection of working fluid in the state. gas 4, out of the tank 105, to the inlet 21 of the second exchanger 102.
  The fourth opening 208 is in fluid communication with the outlet 42 of the pump 104 or the inlet 21 of the second exchanger 102, advantageously direct, that is to say without any element other than a pipe.
• According to one embodiment, the control pressure Pc is equal to the saturation pressure of the pump inlet fluid 41, advantageously during the operation, the operation, of the system.
• According to one embodiment, the valve spring 204 has a stiffness Ks greater than that Kd of the expander spring 202.
• According to one embodiment, the self-regulation module 200 is configured to be in equilibrium, with the regulator 201 closed and the valve 203 closed, when the pressure of the reservoir Pr is both greater than the sum of the pressure. Pc control and stiffness Kd of the spring of the expander 202 and less than the sum of the pressure of Pc control and stiffness Ks of the spring of the valve 204. In this way, the cavitation at the pump inlet is almost zero and the sub-cooling not excessive.
• According to one embodiment, the self-regulation module 200 is configured so that the opening of the valve 203 puts in fluid connection the reservoir 105 and the inlet 21 of the second exchanger 102 or the outlet 42 of the pump 104 by the fourth opening 209.
• According to one embodiment, the self-regulation module 200 is configured so that the opening of the expander 201 puts in fluid connection the reservoir 105 and the outlet 12 of the first exchanger 101 through the third opening 208.
• According to one embodiment, the control pressure production module comprises a balloon 210 filled with working fluid fluidly connected to the second opening 207 of the housing 205, the balloon 210 being arranged to dive into the working fluid of the fluidic circuit. at the outlet 22 of the second exchanger 102 so that the temperature of the fluid contained in the balloon 210 is identical to that of the working fluid of the fluidic circuit at the pump inlet 104. In this way, the pressure of the fluid contained in the balloon 210 , at saturation, is identical to the saturation pressure of the working fluid of the fluidic circuit at pump inlet 104.
• According to one embodiment, the control pressure generation module comprises a source of controlled pressure gas in fluid connection with the second opening 207 of the housing 205, pressure and / or temperature sensors input 41 of pump 104 and means for regulating the pressure of the gas source so as to define a control pressure Pc.
• According to one embodiment, the method comprises a self-regulation step intended to regulate the pressurization and the depressurization of the reservoir 105 so that in equilibrium the expander 201 and the valve 203 are closed when the pressure of the reservoir Pr is both greater than the sum of the control pressure Pc and the stiffness Kd of the spring of the expander 202 and less than the sum of the control pressure Pc and the stiffness Ks of the spring of the valve 204.
• According to one embodiment, the method is such that it comprises when the pressure of the reservoir Pr is greater than the sum of the control pressure Pc and the stiffness Ks of the spring of the valve 204, the opening of the valve 203 putting in fluid connection the reservoir 105 and the inlet 21 of the second exchanger 102 or the outlet 42 of the pump 104 through the fourth opening 209 so as to reduce the pressure of the reservoir Pr and withdraw by suction towards the reservoir 105, fluid of the fluidic circuit.
• According to one embodiment, the method is such that it comprises when the pressure of the reservoir Pr is less than the control pressure Pc added to the stiffness Kd of the spring of the expander 202, the opening of the expander putting in fluid connection the reservoir 105 and the outlet 12 of the first exchanger 101 through the third opening 208 so as to increase the pressure of the reservoir Pr, and add by injection from the reservoir 105 of the working fluid into the fluid circuit.
• ∘ The output 42 of the pump 104 is directly connected to the inlet 11 of the first exchanger 101.
• ∘ The output 12 of the first exchanger 101 is directly connected to the input 31 of the expander 103.
• ∘ The outlet 32 of the expander 103 is directly connected to the inlet 21 of the second exchanger 102.
• The outlet 22 of the second heat exchanger 102 is directly connected to the pump 104.
• The reservoir 105 is directly connected to the fluid circuit between the outlet 22 of the second exchanger 102 and the pump inlet 104.
• ∘ The fluidic circuit is hermetic, preferentially the system is hermetic. This advantageously makes it possible to limit the risks for the environment and for the man when they are toxic.

The invention also makes it possible to minimize the load required by the confinement of the working fluid. However, the working fluid can represent up to more than 20% of the total cost of a Rankine machine. The invention thus minimizes the capital and operating cost of such a system.

An advantage of the invention is to be able to control the fluid load and thus the subcooling, so that it is neither too small (risk of cavitation) nor too large (degradation of the overall performance of the cycle)

• Selon un mode de réalisation avantageux, mais non limitatif, le fluide de travail est un fluide organique. Ce type de fluide permet d'atteindre un régime supercritique, régime pour autant non limitatif de l'invention, même à des températures relativement basses en sortie d'échangeur chaud. On entend par fluide organique, un fluide composé de molécules ou d'un mélange de molécules constituées d'atomes de carbone, d'hydrogène et éventuellement d'autres atomes tels que par exemple l'oxygène, le fluor, l'azote, le chlore, le brome.
• Dans un autre mode de réalisation, le fluide de travail n'est pas un fluide organique.
• Selon un mode de réalisation, le premier échangeur est configuré pour amener à sa sortie le fluide de travail à une température inférieure à 200°C et de préférence inférieure à 150°C.
• Selon un mode de réalisation, le circuit est configuré de manière à ce que la température du fluide de travail en sortie 12 du premier échangeur 101 soit comprise entre la température ambiante et 200°C et de préférence entre la température ambiante et 150°C.
• Selon un mode de réalisation, le système comprend la source chaude 1. La source chaude 1 et le premier échangeur 101 sont configurés pour fournir à la sortie du premier échangeur une température pour le fluide de travail inférieure à 200°C et de préférence inférieure à 150°C. Selon un mode de réalisation, le fluide de travail est frigorigène et choisi parmi le R410a, le R134a, le R227ea, ou le R245fa. Ces fluides permettent d'atteindre un régime supercritique avec des sources chaudes aux températures inférieures à 200°C.Ils sont donc particulièrement avantageux pour produire de l'énergie à partir de rejets thermiques d'usines ou de moteurs thermiques.
• Selon un mode de réalisation, le deuxième échangeur 102 est configuré pour amener à sa sortie 22 le fluide de travail à une température comprise entre la température ambiante et 150°C, la température du fluide de travail en sortie 22 du deuxième échangeur 102 étant inférieure à la température du fluide de travail en sortie 12 du premier échangeur 101.
• Selon un mode de réalisation, le système comprend la première source de chaleur 1, la première source de chaleur 1 étant couplée thermiquement avec un circuit de rejet thermique d'une usine ou d'un moteur.
• Selon un mode de réalisation, le premier échangeur 101 de chaleur est configuré de sorte à chauffer le fluide de travail ; l'expanseur 103 est configuré de sorte à diminuer la pression du fluide de travail et le deuxième échangeur 102 de chaleur est configuré de sorte à refroidir le fluide de travail. La pompe 104 est configurée de sorte à augmenter la pression du fluide de travail.
• Selon un mode de réalisation, le système comprend un dispositif de conversion d'énergie configuré pour convertir un mouvement mécanique produit par l'expanseur 103 en une énergie électrique ou mécanique et configuré de manière à ce que la puissance fournie par le dispositif de conversion d'énergie soit inférieure à 100 kW.
• Selon un mode de réalisation, l'expanseur 103 est une turbine, de préférence cinétique.
• Selon un mode de réalisation, l'expanseur 103 est une machine volumétrique.
• Selon un mode de réalisation, l'expanseur 103 est une machine volumétrique, du type suivant : un compresseur volumétrique fonctionnant en expanseur.
• Selon un mode de réalisation, l'expanseur 103 est une machine hermétique ; ladite machine comprenant l'expanseur, un arbre et l'alternateur; l'expanseur étant raccordé à l'arbre et l'arbre étant raccordé à l'alternateur.

The invention thus provides an effective solution for valuing thermal discharges with relatively low temperatures.

• According to an advantageous embodiment, but not limiting, the working fluid is an organic fluid. This type of fluid makes it possible to reach a supercritical regime, a non-limiting regime of the invention, even at relatively low temperatures at the outlet of the hot exchanger. By organic fluid is meant a fluid composed of molecules or a mixture of molecules consisting of carbon atoms, hydrogen and possibly other atoms such as, for example, oxygen, fluorine, nitrogen, chlorine, bromine.
• In another embodiment, the working fluid is not an organic fluid.
• According to one embodiment, the first heat exchanger is configured to bring the working fluid to its outlet at a temperature below 200 ° C. and preferably below 150 ° C.
• According to one embodiment, the circuit is configured so that the temperature of the output working fluid 12 of the first exchanger 101 is between room temperature and 200 ° C and preferably between room temperature and 150 ° C.
• According to one embodiment, the system comprises the hot source 1. The hot source 1 and the first exchanger 101 are configured to provide at the outlet of the first heat exchanger a temperature for the working fluid of less than 200 ° C. and preferably less than 200 ° C. 150 ° C. According to one embodiment, the working fluid is refrigerant and selected from R410a, R134a, the R227ea, or the R245fa. These fluids make it possible to reach a supercritical regime with hot springs at temperatures below 200 ° C. They are therefore particularly advantageous for producing energy from thermal discharges from factories or thermal engines.
• According to one embodiment, the second heat exchanger 102 is configured to bring the working fluid to its outlet 22 at a temperature between ambient temperature and 150 ° C., the temperature of the working fluid at the outlet 22 of the second heat exchanger 102 being less than at the temperature of the working fluid at the outlet 12 of the first exchanger 101.
• According to one embodiment, the system comprises the first heat source 1, the first heat source 1 being thermally coupled with a heat rejection circuit of a plant or a motor.
• According to one embodiment, the first heat exchanger 101 is configured to heat the working fluid; the expander 103 is configured to decrease the pressure of the working fluid and the second heat exchanger 102 is configured to cool the working fluid. The pump 104 is configured to increase the pressure of the working fluid.
• According to one embodiment, the system comprises an energy conversion device configured to convert a mechanical movement produced by the expander 103 into electrical or mechanical energy and configured so that the power provided by the conversion device energy is less than 100 kW.
• According to one embodiment, the expander 103 is a turbine, preferably kinetic.
• According to one embodiment, the expander 103 is a volumetric machine.
• According to one embodiment, the expander 103 is a volumetric machine, of the following type: a volumetric compressor operating as an expander.
• According to one embodiment, the expander 103 is a hermetic machine; said machine comprising the expander, a shaft and the alternator; the expander being connected to the shaft and the shaft being connected to the alternator.

For the remainder of the description, the term "high" and "low", or their derivatives, a relative positioning quality of an element of the system according to the invention when it is installed in a functional manner, the "high" 'being oriented away from the ground and the bottom facing towards the ground. The upper end is at the top and the lower end is at the bottom.

The upstream and the downstream at a given point are taken with reference to the direction of circulation of the fluid in the circuit.

In the present description, the expression "A fluidically connected to B" does not necessarily mean that there is no organ between A and B.

• Un fluide de travail. Ce fluide de travail est avantageusement frigorigène. Le fluide de travail est de préférence organique ce qui permet éventuellement d'atteindre un régime supercritique (également désigné supercritique) tout en conservant des niveaux de pression et de température relativement limités. Le fluide de travail est de préférence choisi parmi le R410a, le R134a, le R227a, le R245fa. On entend par fluide supercritique, un fluide ayant atteint un régime supercritique.
• Un premier échangeur. 101 Ce premier échangeur 101 est thermiquement couplé à une première source de chaleur 1, dénommée source chaude, par exemple chauffée par les rejets thermiques. De préférence, il permet au fluide d'atteindre un régime supercritique. Le premier échangeur peut ainsi être qualifié d'évaporateur en cas de fonctionnement en régime sous-critique. Le fluide de travail entre par l'entrée 11 dans le premier échangeur 101 à l'état liquide comprimé et ressort à la sortie 12 du premier échangeur 101 à l'état de vapeur comprimée. La température critique du fluide de travail est, par exemple de l'ordre de 70°C, pour un fluide de travail de type gaz réfrigérant R410a. Le R410a est l'un des fluides frigorigènes les plus fréquemment utilisés pour faire fonctionner une pompe à chaleur. Le R410a présente l'avantage de ne pas être nocif pour la couche d'ozone, tout en présentant un bon rendement énergétique. Il a notamment une capacité de compression et une puissance frigorifique plus élevées que beaucoup d'autres fluides frigorigènes. Il augmente donc non seulement les possibilités de chauffage (même à basse température), mais également de refroidissement. La température critique est, par exemple, de l'ordre de : 101°C pour le fluide R134a, 103°C pour le fluide R227a et 154°C pour le fluide R245fa.
• Un expanseur 103 tel que par exemple un compresseur volumétrique. Cet expanseur 103 permet de détendre le fluide et de produire une énergie mécanique à partir de cette détente. Le fluide entre par une entrée 31 de l'expanseur 103 sous forme de vapeur comprimée haute pression et ressort à la sortie 32 de l'expanseur 103 sous forme de vapeur détendue basse pression. Dans un mode de réalisation, cette énergie est récupérée sur un arbre tournant. Cette énergie mécanique peut ensuite être récupérée sous forme électrique au niveau d'un l'alternateur situé sur ledit arbre tournant. L'expanseur 103 est avantageusement dérivé d'un compresseur volumétrique conventionnel de l'industrie frigorifique.
• un deuxième échangeur de chaleur 102 thermiquement couplé à une deuxième source de chaleur 2, plus froide que la première source de chaleur 1 et permettant de refroidir le fluide de travail. Lors de ce refroidissement, la température de saturation est atteinte. Le refroidissement s'accompagne dès lors du phénomène de condensation. Le fluide pénètre dans le deuxième échangeur 102 par l'entrée 21 à l'état de vapeur détendue basse pression et ressort à la sortie 22 à l'état liquide.
• une pompe. De préférence, elle permet au fluide de travail d'être comprimé. Le fluide de travail pénètre au niveau de l'entrée 41 de pompe 104 à l'état liquide et ressort à la sortie 42 à l'état liquide comprimée haute pression.

The figure 1 illustrates an exemplary system according to the present invention. This system is particularly advantageous for a small power production (for example from a few kilowatts to a hundred kilowatts). It is configured to implement a Rankine thermodynamic cycle. It includes commonly used components:

• A working fluid. This working fluid is advantageously refrigerant. The working fluid is preferably organic, which can optionally achieve a supercritical regime (also called supercritical) while maintaining relatively low pressure and temperature levels. The working fluid is preferably selected from R410a, R134a, R227a, R245fa. By supercritical fluid is meant a fluid having reached a supercritical regime.
• A first exchanger. 101 This first heat exchanger 101 is thermally coupled to a first heat source 1, called hot source, for example heated by heat discharges. Preferably, it allows the fluid to reach a supercritical regime. The first exchanger can thus be qualified as an evaporator in the case of subcritical operation. The working fluid enters the inlet 11 into the first exchanger 101 in the compressed liquid state and exits at the outlet 12 of the first exchanger 101 in the compressed vapor state. The critical temperature of the working fluid is, for example of the order of 70 ° C, for a refrigerant gas working fluid R410a. R410a is one of the most frequently used refrigerants to operate a heat pump. R410a has the advantage of not being harmful to the ozone layer, while being energy efficient. In particular, it has a higher compression capacity and cooling capacity than many other refrigerants. It thus increases not only the possibilities of heating (even at low temperature), but also of cooling. The critical temperature is, for example, of the order of: 101 ° C for the fluid R134a, 103 ° C for the fluid R227a and 154 ° C for the fluid R245fa.
• An expander 103 such as for example a volumetric compressor. This expander 103 makes it possible to relax the fluid and to produce mechanical energy from this trigger. The fluid enters through an inlet 31 of the expander 103 in the form of high pressure compressed vapor and exits at the outlet 32 of the expander 103 in the form of a low-pressure expanded vapor. In one embodiment, this energy is recovered on a rotating shaft. This mechanical energy can then be recovered in electrical form at an alternator located on said rotating shaft. The expander 103 is advantageously derived from a conventional volumetric compressor of the refrigeration industry.
• a second heat exchanger 102 thermally coupled to a second heat source 2, cooler than the first heat source 1 and for cooling the working fluid. During this cooling, the saturation temperature is reached. The cooling is then accompanied by the phenomenon of condensation. The fluid enters the second exchanger 102 through the inlet 21 in the state of low-pressure expanded vapor and leaves the outlet 22 in the liquid state.
• a pump. Preferably, it allows the working fluid to be compressed. The working fluid enters the pump inlet 104 in the liquid state and exits at the outlet 42 in the compressed high pressure liquid state.

The outlet 42 of the pump 104 is in fluid communication with the inlet 11 of the first exchanger 101, advantageously by a first exchanger pipe 110. The outlet 12 of the first exchanger 101 is in fluid communication with the inlet 31 of the expander 103, advantageously by an expander line 111. The outlet 32 of the expander 103 is in fluid communication with the inlet 21 of the second exchanger 102, advantageously by a second exchanger line 112. The outlet 22 of the second exchanger 102 is in fluid communication with the pump inlet 104, advantageously by a pump line 113.

The fluidic circuit is advantageously a closed circuit.

Typically, the system according to the invention comprises a reservoir 105 configured to receive and advantageously store the working fluid. The reservoir 105 is arranged between the second heat exchanger 102 and the pump 104, more precisely between the outlet 22 of the second heat exchanger 102 and the pump inlet 104. The reservoir 105 is connected to the fluid circuit via a piping pipe 114. The tank 105 is said to be offline.

The reservoir 105 is connected directly via the tapping pipe 114 to the fluid circuit. The reservoir 105 is said to be continuously connected to the fluid circuit. The tapping pipe 114 does not include a pump or valve type organ.

The reservoir 105 advantageously receives the working fluid simultaneously in two states, liquid 3 and gas 4. The reservoir is subjected to saturation conditions of the working fluid allowing the fluid to be simultaneously in the liquid state 3 and the gaseous state 4 in the reservoir 105. The fluid in the liquid state 3 is located in the lower part of the reservoir 105 while the fluid in the gaseous state 4 is located in the upper part of the reservoir 105.

The arrangement of the reservoir 105 is configured so that the pressure of the reservoir Pr is uniform with the inlet pressure 41 of the pump 104. As a result, the reservoir 105, and in particular the tapping pipe 114, is arranged in close proximity to and sufficient in the The inlet pipe 104 is preferably of reduced length and horizontal. In the immediate vicinity, for example: at least one meter, preferably less than 0.5 meter, or even less than 0.2 meter; this proximity of the reservoir 105 and the inlet 41 of the pump 104 also allows a rapid restoration of the pressure at the inlet 41 of the pump 104 to limit the risk of cavitation.

According to the invention, the system comprises a device for regulating the fluidic charge circulating in the fluidic circuit. This control device is configured to operate in a closed circuit with the fluid circuit. That is, the self-regulating device uses only the working fluid present in the fluid circuit and in the tank 105. The regulating device is configured to maintain saturation conditions in the tank 105.

The control device is configured so that at the pump inlet 104 the working fluid temperature is equal to the fluid saturation temperature minus the sub-cooling temperature difference. Likewise, the inlet pressure of pump 104 is uniform with the pressure of reservoir 105.

The regulating device comprises elements of preferential thermal energy supply in the tank 105 intended to increase the pressure of the reservoir and inject the working fluid from the reservoir 105 to the fluid circuit. The energy supply elements increase the enthalpy of the reservoir, the temperature of the fluid in the reservoir 105 as well as the pressure increases while the density decreases which induces the displacement of the working fluid from the reservoir 105 to the fluid circuit and more specifically the pump pipe 113. The displacement is done passively, that is to say without mechanical action at the branch pipe 114. The working fluid injected into the fluid circuit is at the liquid state.

The energy supply elements can be diverse as illustrated in FIGS. Figures 5 to 7 .

According to a first embodiment illustrated in figure 5 they comprise one or two or more heating rods 5 dipping into the tank 105. The heating rods 5 heat the working fluid thereby increasing its temperature.

According to a second embodiment illustrated in figure 6 , they comprise a working fluid injection module, in the tank 105, taken at the outlet 12 of the first exchanger 101. The injection module comprises a working fluid injection pipe 116 fluidly connected to a first end at the exit 12 of the first interchange 101 and at a second end to the reservoir 105. The working fluid withdrawn and injected into the reservoir 105 is in the high pressure compressed vapor state. Preferably, the module comprises an injector 6 and / or a valve, or any other injection control means for controlling the injection of working fluid.

According to a third embodiment illustrated in figure 7 they comprise at least partial coupling 7 of the first heat source 1 thus making it possible to increase the enthalpy of the fluid in the tank 105.

The regulating device comprises elements of preferentially thermal energy withdrawal from the tank 105 intended to reduce the pressure of the reservoir and draw the working fluid from the fluid circuit to the reservoir. The energy removal elements reduce the enthalpy of the tank 105, the temperature of the fluid in the tank 105 and the pressure decreases while the density increases which induces the displacement of the working fluid of the fluidic circuit and more specifically the pipe pump 113 to the reservoir 105. The withdrawal of the working fluid from the fluidic circuit is passively by suction without mechanical action at the tapping line 114. The working fluid sucked from the fluid circuit is the liquid state.

The energy removal elements can be various as illustrated in FIGS. Figures 8 to 10 .

According to a first embodiment illustrated in figure 8 they comprise a gaseous working fluid rejection module contained in the reservoir 105 in the direction of the inlet 21 of the second exchanger 102. The rejection module comprises a working medium rejection conduit 115 fluidly connected to the a first end to the reservoir 105 and a second end to the inlet 21 of the second exchanger 102. The fluid discharged from the reservoir and injected at the inlet 21 of the second exchanger 102 is in the gaseous state. Preferably, the module comprises an injector or ejector 9 and / or a pump and / or a valve, for controlling the rejection of the working fluid.

According to a second embodiment illustrated in figure 9 , they comprise a working fluid injection module, in the tank 105, taken at the outlet 42 of the pump 104. The injection module comprises a working fluid injection pipe 117 fluidly connected to a first end at the outlet 41 of the pump 104 and at a second end to the reservoir 105. The working fluid withdrawn and injected into the reservoir is in the relaxed state of liquid. Preferably, the module comprises an injector 8 and / or a valve, intended to control the injection of working fluid.

According to a third embodiment illustrated in figure 10 , they comprise at least partial coupling 10 of the second heat source 2 thus making it possible to reduce the enthalpy of the fluid in the tank 105.

The variations of the circulating fluidic charge due to the samples and rejections due to the elements of contribution and of energy withdrawal are minimal, punctual and do not have a synergistic influence with the suction or the injection of fluid of work to and from the tank 105.

According to a particular embodiment, the temperature of the hot source 1 is less than 200 ° C and preferably less than 150 ° C and the temperature of the cold source 2 is less than 50 ° C and preferably of the order of 20 ° C. Preferably, the temperature of the cold source 2 is greater than the ambient temperature and more generally of the order of the ambient temperature.

For the first exchanger 101, that is to say the hot exchanger, the maximum temperature is that of the outlet 32 of the expander 103, that is to say a little less than 150 ° C. The minimum temperature is that of the output 42 of the pump 104, that is to say a little higher than the ambient temperature.

For the second exchanger 102, that is to say the cold exchanger, the maximum temperature is that of the outlet of the turbine or other expander 103, that is to say intermediate, between the temperatures of the hot springs. (150 ° C) and cold (20 ° C). The minimum temperature of the second exchanger 102 is that of the temperature of the cold source, that is to say, in general the ambient temperature.

According to a variant that can be used independently, the invention relates to a self-regulation module 200 illustrated in FIGS. Figures 11 to 13 intended to regulate the pressurization and depressurization of the tank 105 to control the fluidic charge in circulation in the fluidic circuit. The self-regulating module 200 is advantageously mechanically operating allowing fully automatic and mechanical regulation.

The self-regulation module 200 illustrated in figure 13 comprises a compensated pressure reducer 201 coupled to a compensated valve 203.

The self-regulating module 200 is configured to prevent the valve 203 and the expander 201 from being in the open position simultaneously.

Preferably, the expander 201 and the valve 203 are arranged in a housing 205. The expander 201 is associated with a spring 202 having stiffness Kd while the valve 203 is associated with a spring 204 having a stiffness Ks. Advantageously, the stiffness Kd of the spring 202 of the regulator 201 is smaller than the stiffness Ks of the valve spring 204 203.

The housing 205 is configured to handle the pressure differentials to regulate the fluidic load circulating in the fluidic circuit. The casing 205 is fluidly connected to the elements whose pressure must be controlled. According to the embodiment in which the self-regulation module 200 is associated with the device for regulating the fluidic charge circulating in the fluidic circuit, the casing 205 is connected to the device for regulating the fluidic load and more specifically to the elements for energy supply and energy withdrawal. In particular according to the embodiment in which the energy supply element comprises a working fluid injection module taken at the outlet 12 of the first exchanger 101 and the energy removal element comprises a rejection module working fluid in the gaseous state 4 out of the tank 105 to the inlet 21 of the second exchanger 102 or a working fluid injection module taken at the inlet 41 of the pump 104.

The housing 205 is fluidly connected to the tank 105, preferably it is connected directly by a pipe so as to be The pressure of the reservoir Pr is exerted on the pressure reducer 201 and the valve 203. The housing 205 comprises a first opening 206 allowing the fluid connection of the reservoir 105 with the self-regulation module 200.

The housing 205 is fluidly connected to a means for producing a control pressure Pc preferably corresponding to the saturation pressure of the working fluid at the inlet 41 of the pump 104. The control pressure Pc is exerted on the regulator 201 and the valve 203. The housing 205 comprises a second opening 207 allowing the fluidic connection of the control pressure with the self-regulation module 200.

The control pressure Pc and the pressure of the reservoir Pr are relatively opposed to each other with respect to the valve 203 and the expander 201. That is, the control pressure Pc and the reservoir pressure Pr exert opposing forces on the valve 203 and the expander 201.

The housing 205 is fluidly connected to the fluidic circuit, precisely at the outlet 12 of the first exchanger 101, preferably it is connected directly by a pipe 116. A first end of the pipe 116 is stitched on the outlet 12. The housing 205 comprises a third opening 208 allowing the fluidic connection of the second end of the pipe 116 with the self-regulation module 200.

The housing 205 is fluidly connected to the fluid circuit, precisely at the inlet 41 of the pump 104, preferably it is connected directly by a pipe 117. A first end of the pipe 117 is stitched on the pump inlet 104. Case 205 includes a fourth opening 209 for fluidically connecting the second end of line 117 with self-regulating module 200.

Alternatively, the housing 205 is fluidly connected to the fluidic circuit, precisely at the inlet 21 of the second exchanger 102, preferably it is connected directly via a pipe 115. A first end of the pipe 115 is stitched on the inlet 21. The housing 205 comprises a fourth opening 209 allowing the fluidic connection of the second end of the pipe 117 with the self-regulation module 200.

The figure 14 illustrates different cases of self-regulation of the fluidic charge circulating in the fluidic circuit.

Advantageously, the stiffness of the expansion valve spring Kd is lower than the stiffness of the valve spring Ks. First case (301), when the pressure of the tank Pr is greater than the sum of the control pressure Pc and the stiffness of the spring. In this case, the tank pressure Pr is also greater than the sum of the control pressure Pc and the expansion valve stiffness Kd. Thus, the force exerted by the pressure of the reservoir Pr by the first opening 206 of the housing 205 on the expander 201 and the valve 203 is greater than the force of the control pressure Pc exerted by the second opening 207 of the housing 205 on the expander 201 and the valve 203. The stiffness of the expansion and valve springs Kd and Ks do not compensate for this differential inducing the opening of the valve 203 (304) and now the expander 201 closed.

The opening of the valve 203 means that the fourth opening 209 of the housing 205 is open leaving, according to the embodiment, either to enter, into the reservoir, the working fluid taken at the inlet 41 of the pump 104, or to leave the reservoir 105 the working fluid in the gaseous state towards the inlet 21 of the second exchanger 102.

This displacement of fluid causes a drop in the pressure (307) in the reservoir 105 generating a suction 120 of working fluid to the reservoir from the fluid circuit. The reduction of the amount of working fluid in the fluid circuit makes it possible to reduce the pump inlet pressure and thus the subcooling, which limits the performance degradation of the Rankine machine.

Since the pressure of the reservoir Pr has decreased, it is now in the second case (302), ie less than the sum of the control pressure Pc and the stiffness of the valve spring Ks, and remains greater than the sum of the control pressure Pc and the regulator stiffness Kd.

Thus, the force exerted by the pressure of the reservoir Pr by the first opening 206 of the housing 205 on the expander 201 and the valve 203 is greater than the force of the control pressure Pc exerted by the second opening 207 of the housing 205 on the expander 201 and the valve 203. The stiffness expansion and valve springs Kd and Ks compensate for this differential now closed valve 203 and expander 201 (305).

Since the expander 201 and the valve 203 are closed, there is no fluid circulation whatsoever in the self-regulation module 200 or between the reservoir 105 and the fluid circuit.

When the tank pressure decreases, the tank pressure Pr is less than the sum of the control pressure Pc and the stiffness of the valve spring Ks and the sum of the control pressure Pc and the stiffness of the expansion spring Kd (303).

The force exerted by the pressure of the reservoir Pr by the first opening 206 of the housing 205 on the expander 201 and the valve 203 is greater than the force of the control pressure Pc exerted by the second opening 207 of the housing 205 on the expander 201 and the valve 203 .. The stiffness of the expansion spring and valve Kd and Ks do not compensate for this differential inducing the opening of the expander 201 (306) and now the valve 203 closed.

The opening of the expander 201 means that the third opening 208 of the housing 205 is open allowing the working fluid withdrawn from the outlet 12 of the first exchanger 101 to enter the reservoir. This displacement of the fluid causes an increase in the pressure (309). in the reservoir Pr generating an injection 121 of working fluid to the fluid circuit from the tank 105. The increase of the amount of working fluid in the fluid circuit makes it possible to increase the pump inlet pressure 104 and thus the subcooling, limiting the risk of cavitation.

The control pressure Pc is transmitted to the self-regulation module 200 at the second opening 207 by a control pressure production module.

Several variants are possible for the module for producing a control pressure. Two of them are illustrated in Figures 11 and 12 .

The figure 12 indicates that the control pressure is transmitted by a production module of the gas source type whose pressure is regulated. To regulate the cavitation margin at pump inlet 104, the module comprises means for measuring measurements of input variable variables 41 of pump 104 such as temperature and pressure and means for controlling the control pressure Pc according to these variables. In this case, the self-regulating module 200 is configured to ensure that the separation between the second opening 207 and the rest of the module 200 is hermetic so as to ensure that there is no contamination of the working fluid. not the gas from the control pressure production module.

The figure 12 illustrates, moreover, a part of the fluidic circuit of the system according to the invention with the pump 104, the first heat exchanger 101, the second heat exchanger 102, the tank 105, the self-regulation module 200. Between the outlet 22 of the second heat exchanger 102 and the outlet 12 of the first exchanger 101, are arranged in the direction of circulation of the working fluid, the tapping pipe 114 of the reservoir 105, the pump 104, the injection pipe 117 of the energy removal element, the first exchanger 101 and the injection pipe 116 of the energy supply element.

• au réservoir 105 par la première ouverture 206,
• à l'élément d'apport d'énergie du dispositif de régulation de la charge fluidique, étant dans ce cas-là un module d'injection de fluide dans le réservoir 105 prélevé en sortie 12 du premier échangeur 101, la sortie 12 étant directement raccordée à la troisième ouverture 208 du module d'autorégulation 200 par la conduite 116,
• à l'élément de retrait d'énergie du dispositif de régulation de la charge fluidique, étant dans ce cas-là un module d'injection de fluide dans le réservoir prélevé en entrée 41 de la pompe 104, l'entrée 41 étant directement raccordée à la quatrième ouverture 209 du module d'autorégulation 200 par la conduite 117.

The self-regulation module 200 being fluidly connected by these different openings:

• at the reservoir 105 by the first opening 206,
• the fluid supply element of the fluidic pressure regulating device, being in this case a fluid injection module in the reservoir 105 taken at the outlet 12 of the first exchanger 101, the outlet 12 being directly connected to the third opening 208 of the self-regulating module 200 via line 116,
• to the energy removal element of the device for regulating the fluidic load, being in this case a fluid injection module in the tank taken at the inlet 41 of the pump 104, the inlet 41 being directly connected at the fourth opening 209 of the self-regulating module 200 through line 117.

The figure 11 indicates that the control pressure is transmitted by a particular production module. The production module comprises a balloon 210 filled with working fluid thus limiting the risk of contamination, fluidly connected to the second opening 207 of the self-regulation module 200. Preferably, the balloon 210 is maintained at saturation temperature of the fluid at the inlet 41 of the pump 104. For this purpose, the balloon 210 is advantageously immersed in the working fluid circulating in the fluid circuit. Preferably, the balloon 210 is arranged at the outlet 22 of the second heat exchanger 102. In this way, the control pressure Pc is equal to the pressure of the fluid in the balloon 201, itself equal to the saturation pressure of the fluid circulating in the the pump line 113, that is to say the saturation pressure at the inlet 41 of the pump 104.

The figure 11 illustrates, moreover, a part of the fluidic circuit of the system according to the invention with the pump 104, the first heat exchanger 101, the second heat exchanger 102, the tank 105, the self-regulation module 200. Between the outlet 22 of the second heat exchanger 102 and the inlet 21 of the second exchanger 101, are arranged in the direction of circulation of the working fluid, the balloon 210 immersed in the pipe 113 of the pump, the tapping pipe 114 of the reservoir 105, the pump 104, the first exchanger 101, the injection line 116 of the energy supply element, the expander (not shown) and the rejection line 115 of the energy removal element.

• au réservoir 105 par la première ouverture 206,
• à l'élément d'apport d'énergie du dispositif de régulation de la charge fluidique, étant dans ce cas-là un module d'injection de fluide dans le réservoir prélevé en sortie 12 du premier échangeur 101, la sortie 12 étant directement raccordée à la troisième ouverture 208 du module d'autorégulation 200 par la conduite 116,
• à l'élément de retrait d'énergie du dispositif de régulation de la charge fluidique, étant dans ce cas-là un module de réjection de fluide à l'état gazeux du réservoir vers l'entrée 21 du deuxième échangeur 102, l'entrée 21 étant directement raccordée à la quatrième ouverture 209 du module d'autorégulation 200 par la conduite 115.

The self-regulation module being fluidly connected by these different openings:

• at the reservoir 105 by the first opening 206,
• the fluid supply element of the device for regulating the fluidic load, being in this case a fluid injection module in the reservoir taken at the outlet 12 of the first exchanger 101, the outlet 12 being directly connected at the third opening 208 of the self-regulation module 200 via the pipe 116,
• to the energy removal element of the device for regulating the fluidic load, being in this case a fluid rejection module in the gaseous state of the reservoir towards the inlet 21 of the second exchanger 102, the inlet 21 being directly connected to the fourth opening 209 of the self-regulating module 200 via line 115.

The basic principle of the invention provides numerous advantages and in particular that of being able to better control the charge of the fluid and therefore the subcooling, so that it is neither too small (risk of cavitation) nor too large (degradation of the overall performance of the cycle).

A further advantage of the invention is also to reduce the risk of cavitation in the pump. The inlet pressure in the pump is regulated in the case of the invention. Indeed, the cavitation margin for a given installation is expressed by the difference between the inlet pressure minus the saturation vapor pressure and a characteristic value of the pump (NPSH: net positive suction head).

Processes of electric energy generation in the electrical industry or in the transformation industry (metallurgy, chemistry, paper mill, cement plant, food industry) with heat rejection even at low temperature, transport with thermal engine (truck, automobile , boat, train), solar concentrating, geothermal or biomass.

• Fluide de travail : R134a
• Température de sortie condenseur 102 : 20 °C
• Température de sortie évaporateur 101 : 100 °C
• NPSH requis à la pompe 104 : 0.5 bar
• Pression de sortie pompe 104 : 35 bars

As a non-limitative example
For an ORC cycle with the following characteristics:

• Work fluid: R134a
• Condenser outlet temperature 102: 20 ° C
• Evaporator outlet temperature 101: 100 ° C.
• NPSH required at pump 104: 0.5 bar
• Pump output pressure 104: 35 bar

• Température en entrée pompe, et dans le ballon : 20°C soit une pression de saturation de 5.71 bars. Donc Pc = 5.71 bars.
• Pression en entrée pompe correspondant à un NPSH de 0.5 bar, donc Pr = 5.71+0.5 = 6.21 bars
• Température dans le réservoir (saturation) = 22.7°C

Cas d'une augmentation de température en sortie condenseur 102 de 20°C à 22°C :

• Température en entrée 41 de pompe 104 et dans le ballon 210 : 22°C, soit une pression de saturation de 6.08 bars. Donc Pc = 6.08 bars.
• Comme Pr (6.21 bars) < Pc (6.08 bars) + Kd (0.5 bar), le détendeur 201 s'ouvre et permet l'injection de fluide haute température dans le réservoir 105.
• Du fluide est injecté dans le circuit fluidique de l'ORC, la pression dans la conduite d'entrée pompe 113 et dans le réservoir augmente jusqu'à Pr = Pc + Kd = 6.58 bars.
• Les conditions en entrée 41 de pompe 104 donnent un NPSH de 0.5 bar.
• Température dans le réservoir 105 (saturation) = 24.7°C

Cas d'une baisse de température en sortie condenseur 102 de 22°C à 18°C :

• Température en entrée 41 de pompe 104 et dans le ballon 210 : 18°C, soit une pression de saturation de 5.37 bars. Donc Pc = 5.37 bars.
• Comme Pr (6.58 bars) < Pc (5.37 bars) + Ks (1 bar), la soupape 203 s'ouvre et permet la réjection de vapeur du réservoir 105 vers le condenseur 102.
• Du fluide est aspiré à la sortie du condenseur 102 et entre dans le réservoir 105. La pression dans la conduite entrée 41 de pompe 104 et dans le réservoir 105 baisse jusqu'à Pr = Pc + Ks = 6.37 bars.
• Les conditions en entrée 41 de pompe 104 donnent un NPSH de 1 bar.
• Température dans le réservoir 105 (saturation) = 23.7°C

In the case of Figure 11 with depressurization by vapor rejection. The control pressure Pc is equal to the saturation pressure at the inlet 41 of the pump 104. Therefore, a spring stiffener of the pressure reducer Kd corresponding to a pressure equal to the required NPSH of 0.5 bar is chosen. If a hysteresis of 0.5 bar is desired, a valve spring stiffness Ks is chosen with an equivalent pressure 0.5 bar greater than Kd, ie 1 bar.
Equilibrium :

• Temperature at the pump inlet, and in the flask: 20 ° C is a saturation pressure of 5.71 bar. So Pc = 5.71 bars.
• Pressure at the pump inlet corresponding to an NPSH of 0.5 bar, therefore Pr = 5.71 + 0.5 = 6.21 bar
• Temperature in the tank (saturation) = 22.7 ° C

Case of a temperature increase at the condenser outlet 102 from 20 ° C. to 22 ° C.

• Temperature at the inlet 41 of the pump 104 and in the tank 210: 22 ° C., ie a saturation pressure of 6.08 bar. So Pc = 6.08 bars.
• As Pr (6.21 bar) <Pc (6.08 bar) + Kd (0.5 bar), the expander 201 opens and allows the injection of high temperature fluid into the reservoir 105.
• Fluid is injected into the fluidic circuit of the ORC, the pressure in the pump inlet pipe 113 and in the reservoir increases to Pr = Pc + Kd = 6.58 bar.
• The inlet conditions 41 of pump 104 give an NPSH of 0.5 bar.
• Temperature in the tank 105 (saturation) = 24.7 ° C.

Case of a temperature drop at the condenser outlet 102 from 22 ° C to 18 ° C:

• Temperature at the inlet 41 of the pump 104 and in the balloon 210: 18 ° C., ie a saturation pressure of 5.37 bar. So Pc = 5.37 bars.
• As Pr (6.58 bar) <Pc (5.37 bar) + Ks (1 bar), the valve 203 opens and allows the vapor rejection of the tank 105 to the condenser 102.
• Fluid is sucked at the outlet of the condenser 102 and enters the tank 105. The pressure in the inlet line 41 of the pump 104 and in the tank 105 drops to Pr = Pc + Ks = 6.37 bars.
• The conditions at pump inlet 104 give a NPSH of 1 bar.
• Temperature in the tank 105 (saturation) = 23.7 ° C.

REFERENCES

1. 1. First source of heat
2. 2. Second source of heat colder than first
3. 3. Fluid working in the liquid state
4. 4. Work fluid in the gaseous state
5. 5. Hot rods
6. 6. High temperature fluid injector
7. 7. Bypass of the first source of heat
8. 8. Low temperature fluid injector
9. 9. Fluid ejector in the gaseous state
10. 10. Bypass of the second heat source
11. 11. Entry first exchanger
12. 12. First exchanger outlet

• 21. Second heat exchanger inlet
• 22. Second heat exchanger outlet

• 31. Expander entry
• 32. Expander outlet

• 41. Pump inlet
• 42. Pump outlet

• 100. Rankine Cycle
• 101. First exchanger
• 102. Second exchanger
• 103. Expander
• 104. Pump
• 105. Tank

• 110. Driving first interchange
• 111. Driving expander
• 112. Driving second interchange
• 113. Driving pump
• 114. Conducting tank quilting
• 115. Conduct fluid rejection in the gaseous state
• 116. High temperature fluid injection line
• 117. Low temperature fluid injection line

• 120. Fluid suction
• 121. Fluid Injection

• 200. Self-regulation module
• 201. Regulator
• 202. Regulator spring
• 203. Valve
• 204. Valve spring
• 205. Case
• 206. First opening
• 207. Second opening
• 208. Third opening
• 209. Fourth opening
• 210. Balloon

• 300. Tank pressure
• 301. Tank pressure greater than the sum of the control pressure and the stiffness of the valve spring
• 302. Tank pressure greater than the sum of the control pressure and the stiffness of the expansion valve spring, but less than the sum of the control pressure and the stiffness of the valve spring.
• 303. Tank pressure less than the sum of the control pressure and the stiffness of the expansion valve spring
• 304. Opening valve
• 305. Valve and regulator closure
• 306. Opening regulator
• 307. Tank pressure decreases
• 308. Constant tank pressure
• 309. Tank pressure increases

• Pr. Pressure tank
• Pc. Pressure control
• Kd. Stiffness spring regulator
• Ks. Stiffness spring valve

Claims (20)

An electric or mechanical power generation system comprising a fluid circuit in which a working fluid circulates and comprising a plurality of members traversed by the working fluid and from which: at least one first heat exchanger (101) configured to be thermally coupled to at least one first heat source (1), an expander (103) whose inlet (31) is fluidly connected to an outlet (12) of the first exchanger (101), a second heat exchanger (102) configured to be thermally coupled to a second heat source (2) colder than the first heat source (1) at least one pump (104) configured to move the working fluid in the fluid circuit, at least one reservoir (105) receiving the working fluid and arranged between the second heat exchanger (102) and the pump (104) on a quilting pipe (114), the fluidic circuit being configured so that the working fluid passes successively through at least the pump (104), the first exchanger (101), the expander (103) and the second exchanger (102), then again the pump (104)
characterized in that the system comprises a device for regulating the fluidic charge circulating in the fluid circuit configured to operate in a closed circuit with the fluid circuit and maintain saturation conditions in the reservoir (105) so that the reservoir (105) ) contains the working fluid simultaneously in the liquid state (3) and in the gaseous state (4), the regulating device comprising thermal energy supply elements (5, 6, 7) in the reservoir ( 105) for increasing the pressure of the reservoir (Pr) and inducing the injection of the working fluid from the reservoir into the fluid circuit and the energy removal elements (8, 9, 10) of the reservoir (105) intended to reduce the pressure of the reservoir (Pr) and induce the suction to the reservoir (105) of the working fluid out of the fluid circuit. System according to the preceding claim wherein the reservoir (105) is directly connected to the branch pipe (114) which is itself directly connected to the fluid circuit between the second exchanger (102) and the pump (104), advantageously the system does not include any fluid other than the working fluid. System according to any one of the preceding claims, in which the thermal energy supply elements comprise at least one heating rod (5) immersed in the reservoir (105), and / or an injection module, in the reservoir ( 105), working fluid withdrawn at the outlet (12) of the first exchanger (101), and / or at least a partial coupling (7) of the reservoir (105) with the first heat source (1). System according to any one of the preceding claims, in which the energy removal elements comprise an ejection module, out of the tank (105), of the working fluid in the gaseous state (4) towards the inlet (21) of the second exchanger (102) and / or an injection module, in the reservoir (105), working fluid taken at the outlet (42) of the pump (104), and / or a coupling (10). ) at least partially of the tank (105) with the second heat source (2). The system of any one of claims 1 or 2 including a mechanically operating self-regulating module for regulating the pressurization and depressurization of the reservoir (105). System according to the preceding claim wherein the self-regulation module comprises a compensated expander (201) coupled to a compensated valve (203). System according to any one of the two preceding claims, in which the self-regulation module (200) comprises a housing (205) receiving a pressure reducer (201) associated with a pressure regulator spring (202) and a valve (203) associated with a pressure regulator (202). valve spring (204). System according to any of the three preceding claims wherein the thermal energy supply elements comprise a injection module, in the reservoir (105), working fluid taken at the outlet (12) of the first exchanger (101) and the energy removal elements comprise a gas ejection module in the gaseous state (4), out of the tank (105), in the direction of the inlet (21) of the second exchanger (102) or an injection module, in the reservoir (105), working fluid taken at the outlet (42). ) of the pump (104). System according to the preceding claim wherein the housing (205) comprises a first opening (206) in fluid connection with the reservoir (105) so as to be subjected to the pressure of the reservoir Pr, a second opening (207) in fluid connection with a control pressure production module so as to be subjected to a controlled pressure Pc, a third opening (208) of injection into the reservoir (105) of working fluid taken at the outlet (12) of the first exchanger (101), a fourth opening (209) for injection, into the reservoir (105), of working fluid taken at the outlet (42) of the pump (104) or ejection, out of the reservoir (105), working fluid in the gaseous state (4) to the inlet (21) of the second exchanger (102). System according to the preceding claim wherein the control pressure Pc is equal to the saturation pressure of the pump inlet fluid (41) during the operation of the system. A system as claimed in any one of the preceding claims wherein the valve spring (204) has a stiffness Ks greater than that of the expander spring (202). System according to the preceding claim wherein the self-regulating module (200) is configured to be in equilibrium, with the pressure regulator (201) closed and the valve (203) closed, when the pressure of the reservoir Pr is both greater to the sum of the control pressure Pc and the stiffness Kd of the spring of the expander (202). and less than the sum of the control pressure Pc and the stiffness Ks of the spring of the valve (204). A system as claimed in any one of the preceding two claims wherein the self-regulating module (200) is configured for the opening of the valve (203) to fluidically connect the tank (105) and the inlet (21) of the second heat exchanger (102) or the outlet (42) of the pump (104) through the fourth opening (209). System according to any one of the three preceding claims, in which the self-regulation module (200) is configured so that the opening of the expander (201) puts in fluid connection the reservoir (105) and the outlet (12) of the first exchanger (101) through the third opening (208). A system as claimed in any one of the preceding claims wherein the control pressure producing module comprises a flask (210) filled with working fluid fluidically connected to the second opening (207) of the housing (205), the balloon (210) ) being arranged to dive into the working fluid of the fluidic circuit at the outlet (22) of the second exchanger (102) so that the temperature of the fluid contained in the tank (210) is identical to that of the working fluid of the fluidic circuit in pump inlet (41) (104). A system according to any one of claims 9 to 14 wherein the control pressure generation module comprises a source of controlled pressure gas in fluid connection with the second opening (207) of the housing (205), pressure sensors and and / or at the inlet temperature (41) of the pump (104) and means for regulating the pressure of the source of gas so as to define a control pressure Pc. A method of regulating the fluidic charge circulating in the fluidic circuit of a power generation system according to any one of the preceding claims comprising the steps of: a step of increasing the pressure of the working fluid through the pump (104), a step of heating the working fluid through the first heat exchanger (101), a step of expansion of the working fluid from the first exchanger (101) through the expander (103), a step of cooling the working fluid through the second heat exchanger (102), characterized in that it comprises a step of maintaining saturating conditions in the reservoir (105) to maintain the working fluid simultaneously in two gaseous (4) and liquid (3) states in the reservoir (105) by a step of supplying thermal energy into the reservoir (105) comprising increasing the pressure in the reservoir (105) and adding working fluid into the fluidic circuit by injection from the reservoir (105), or alternatively a step of removing energy from the reservoir (105) comprising decreasing the pressure in the reservoir (105) and withdrawing working fluid from the fluid circuit by suction to the reservoir (105). A method according to the preceding claim in combination with claims 9 and 11 including a self-regulation step for regulating the pressurization and depressurization of the reservoir (105) so that in equilibrium the expander (201) and the valve (203) ) are closed when the pressure of the reservoir Pr is both greater than the sum of the control pressure Pc and the stiffness Kd of the spring of the expander (202) and less than the sum of the control pressure Pc and the stiffness Ks of the spring of the valve (204). Method according to one of the two preceding claims in combination with claims 9 and 11 comprising when the pressure of the reservoir Pr is greater than the sum of the control pressure Pc and the stiffness Ks of the spring (204) of the valve ( 203), the opening of the valve (203) fluidically connecting the reservoir (105) and the inlet (21) of the second heat exchanger (102) or the outlet (42) of the pump (104) through the fourth opening (209) so as to reduce the pressure of the reservoir Pr. Method according to any one of the three preceding claims in combination with claims 9 and 11 comprising when the pressure of the tank Pr is lower than the control pressure Pc added to the stiffness Kd of the expander spring (202), the opening of the expander putting in fluid connection the reservoir (105) and the outlet (12) of the first exchanger (101) through the third opening (208) so as to increase the pressure of the tank Pr.

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