Thermal management system for the turbine of a Carnot battery with buffer tank and associated process

Abstract

Thermal management system for the turbine of a Carnot battery with buffer tank and associated method. The invention is a system comprising a Carnot battery including a power-to-heat conversion module, a thermal storage module, and a heat conversion module, comprising a steam cycle and a turbine arranged on the steam cycle for the production of electricity. The system includes an additional thermal storage unit fluidly connected to the steam cycle and intended for storing steam from the steam cycle and separate from the thermal storage module of the Carnot battery. The additional thermal storage unit includes at least one thermal storage device, a buffer tank and a fluid connection for supplying the buffer tank, a fluid connection for supplying steam to the turbine, a fluid connection for returning steam, a fluid connection for charging steam, and a fluid connection for draining steam.Figure for the abridged version: Fig.1.

Description

Title of the invention: Thermal management system for the turbine of a Carnot battery with buffer tank and associated process. Technical field

[0001] The present invention relates to a thermal management system for the turbine of a Carnot battery and its associated method. The invention is applicable to all systems comprising a heat production unit coupled to a thermodynamic cycle for power generation purposes, for example, nuclear power plants. The invention will find particular application in the reuse of steam cycles from coal-fired power plants. STATE OF THE ART

[0002] The increasing use of intermittent, uncontrollable renewable energies leads to a growing need to compensate for sudden variations in production. In this area, thermal storage makes it possible to store electricity in thermal form during periods of low demand, in order to release it during peak electricity consumption, with the aim of limiting the use of fossil fuel backup systems.

[0003] The concept of storing electricity as heat and releasing it as electricity is called a "Carnot battery".

[0004] A Carnot battery is a system consisting of transforming electricity into heat, then storing this heat and finally transforming this heat into electricity as needed.

[0005] In parallel, electricity production from coal is among the activities with the highest carbon footprint. According to ADEME, a coal-fired power plant emits approximately 1050 tCO2eq / kWh of electricity produced. Therefore, in the coming years and within the framework of the fight against climate change, European countries aim to phase out coal.

[0006] One possibility for recycling coal-fired power plants that is currently being studied is the reuse of the water / steam cycles of existing coal-fired power plants in Carnot batteries. Coal-fired power plants have a coal-fired boiler that supplies, via a water / steam cycle, a turbine which generates electricity.

[0007] The GIZ report: “Repurposing of existing coal-fired power plants into Thermal Storage Plants for renewable power in Chile” presents the technical modifications necessary to use the water / steam cycle of a coal-fired power plant in a Carnot battery as well as an economic analysis for the case of Chile.

[0008] However, this solution has the disadvantage of lacking responsiveness. When The electricity grid operator requests a supply of electricity, and responsiveness is essential. However, starting up a turbine, particularly in a coal-fired power plant, does not allow for rapid start-up and electricity production.

[0009] The document "Preheating procedure for fast start-up of a steam turbine from a cold state" is known, describing a preheating procedure to quickly start the cycle of a steam turbine. Several heat sources are identified for this purpose: steam from an external source, electrical tracing, or hot air. Steam as a heat source comes from an existing steam cycle, particularly given that most power plants have several turbines, at least one of which is always in operation. This implies that the steam cycles of each turbine must be adapted both to supply and receive steam, thus multiplying the number of networks. Operational constraints are also present: preheating requires stable steam parameters, whereas in this case, these are highly dependent on the turbine load.This solution would therefore imply maintaining a stable load on a turbine in operation throughout the preheating period, which is not necessarily compatible with the network requirements.

[0010] There is therefore a need to propose a solution ensuring a quick and easy start-up of turbines used or reused in Carnot batteries. SUMMARY

[0011] To achieve this objective, according to one embodiment, a system is provided comprising a Carnot battery including an electricity-to-heat conversion module, a thermal storage module for the heat produced by the electricity-to-heat conversion module, and a module for converting the heat released from the storage module into electricity, the heat-to-electricity conversion module comprising a steam cycle and a turbine arranged on the steam cycle for expanding the steam for the purpose of electricity production, characterized in that the system includes an additional thermal storage unit fluidly connected to the steam cycle and intended for storing steam from the steam cycle and separate from the thermal storage module of the Carnot battery, the additional thermal storage unit comprising at least one thermal storage device, a buffer tank and a fluid connection for supplying the buffer tank arranged between the steam cycle, downstream of the turbine, and the buffer tank, ensuring the circulation of steam and / or water from the steam cycle to the buffer tank, a pair of preheating fluid connections comprising • a fluid connection for supplying steam to the turbine arranged between the thermal storage device and the steam cycle upstream of the turbine, ensuring the fluid connection from the thermal storage device to the steam cycle so as to provide preheating and / or temperature maintenance of all or part of the steam cycle, and preferably at least of the turbine, and • a return fluid connection arranged between the buffer tank and the thermal storage device to ensure the fluid connection from the buffer tank to the thermal storage device so as to ensure the return of the expanded steam and / or water from the buffer tank to the thermal storage device, a pair of charging fluid connections comprising • a fluidic charging connection arranged between the buffer tank and the thermal storage device to ensure the fluidic connection from the buffer tank to the thermal storage device so as to charge the thermal storage device with thermal energy, and • a fluidic evacuation connection arranged between the storage device and the buffer tank 500 so as to ensure the circulation of water from the storage device to the buffer tank 500.

[0012] The proposed invention overcomes the constraints of the prior art by using a thermal storage unit independent of the Carnot battery storage and dedicated to the function of preheating and / or maintaining the temperature of at least part of the steam cycle, and in particular the turbine and possibly other components of the steam cycle. The invention makes it possible to produce steam directly, without operating the Carnot battery, and with faster steam production; the Carnot battery can be shut down to limit losses. Furthermore, the heat used comes from the Carnot battery, which has been charged from grid electricity when the grid is not under load. This makes it possible to take advantage of low, negative, or even surplus electricity rates, generally from renewable sources, and to avoid the use of fossil fuels.

[0013] The additional storage unit makes it possible to deliver a low thermal power over a long period so as to either maintain at least the turbine and possibly other components of the steam cycle at temperature, or to ensure preheating of it or possibly these.

[0014] According to one possibility, the system comprises a heat exchanger for charging arranged on the thermal storage module of the Carnot battery and on the fluidic charging line preferably originating from the buffer tank 500, indirectly fluidly connecting the buffer tank 500 to the thermal storage device. through the heat exchanger charge 405.

[0015] According to this first embodiment, the indirect connection of the steam cycle to the storage unit via a heat exchanger allows the thermal energy produced and stored in the Carnot battery to be recovered and stored in the additional thermal storage unit. This additional storage unit can then be used to preheat and / or maintain the temperature of all or part of the steam cycle, and in particular the turbine. This configuration facilitates the implementation of the system in the case of a reuse, or retrofit, of a steam cycle and a turbine. Indeed, this configuration does not require adding turbine draw-offs whose pressure, temperature, and flow conditions must be compatible with the needs of the additional thermal storage unit.

[0016] According to one aspect, the invention relates to the use of the system as described below to reuse a steam cycle and a turbine from a coal-fired power plant.

[0017] According to one aspect, the invention relates to a method for preheating and / or maintaining the temperature of a turbine of a system comprising a step of charging the thermal storage device of the additional thermal storage unit including the circulation of steam to the thermal storage device from the buffer tank, and alternatively a step of preheating and / or maintaining the temperature of the turbine including the circulation of steam from the thermal storage device to the steam cycle.

[0018] The method according to the invention makes it possible to use some of the heat generated by the operation of the Carnot battery for storage in anticipation of preheating and / or maintaining the temperature of all or part of the steam cycle, in particular when the release of heat stored in the heat storage module is stopped. BRIEF DESCRIPTION OF THE FIGURES

[0019] The aims, objects, features and advantages of the invention will become clearer from the detailed description of an embodiment thereof, which is illustrated by the following accompanying drawings in which:

[0020] [Fig.1] Fig.1 represents a diagram of a first variant of the invention in which the thermal storage device of the additional storage unit is a PCM thermal storage system and is indirectly connected to the steam cycle for charging.

[0021] [Fig.2] Fig.2 represents a diagram of a second variant of the invention in which the thermal storage device is a vapor accumulator.

[0022] [Fig.3] Fig.3 represents a diagram of a third variant of the invention in which the thermal storage device is a sensitive storage.

[0023] [Fig.4] Fig.4 represents a diagram of a fourth variant of the invention in of which the additional storage unit comprises two thermal storage devices: a PCM thermal storage system and a vapor accumulator.

[0024] [Fig. 5] Figure 5 shows a diagram of a fifth embodiment of the invention in which the additional storage unit includes three thermal storage devices: a PCM thermal storage system, a vapor accumulator and a sensitive storage.

[0025] The drawings are given by way of example and are not limiting of the invention. They constitute schematic representations of principle intended to facilitate understanding of the invention and are not necessarily to scale with practical applications. DETAILED DESCRIPTION

[0026] Before proceeding with a detailed review of embodiments of the invention, optional features that may be used in combination or alternatively are listed below: - According to one example, the Carnot battery includes an interface heat exchanger 304 arranged between the heat storage module 200 and the steam cycle 301 so as to ensure heat transfer from the heat storage module 200 to the steam cycle 301, the interface heat exchanger 304 being arranged on the steam cycle 301 upstream of the turbine 302, the supply connection 401 of the turbine 301 being connected to the steam cycle 301 downstream of the interface heat exchanger 304; - According to one example, the Carnot battery includes an interface heat exchanger 304 arranged between the produced heat storage module 200 and the steam cycle 301 so as to ensure heat transfer from the thermal storage module 200 to the steam cycle 301, the interface heat exchanger 304 being arranged on the steam cycle 301 upstream of the turbine 302, the supply connection 401 of the turbine 301 being connected to the steam cycle 301 upstream of the interface heat exchanger 304; - According to one example, the thermal storage device includes a phase change material (PCM) thermal storage system (TSS); - According to one example, the thermal storage device includes a steam accumulator; - According to one example, the thermal storage device includes sensitive storage; - According to one example, the system does not include an external heat source other than the Carnot battery for steam production in the steam cycle; - According to one example, the steam cycle and the turbine are part of, more precisely are thermally connected to or powered by a coal-fired power plant; - According to one example, the thermal storage module 200 for heat produced from the Carnot battery includes a fluidic circuit 201 intended to receive at least one molten salt and ensuring the fluidic connection between a cold tank 202 intended to store the cold molten salt, a hot tank 203 intended to store the hot molten salt, a pump 204, the electricity-to-heat conversion module 100, and an interface heat exchanger 304 through which the steam cycle 301 circulates; - According to one example, the process includes a stage of electricity production by the turbine, the stage of charging the thermal storage device being carried out during this electricity production stage; - According to one example, the preheating and / or temperature maintenance stage of the turbine is carried out alternately with the electricity production stage.

[0027] For the remainder of this description, 'top' and 'bottom', or their derivatives, refer to a relative positioning quality of an element of the system or when it is functionally installed, with 'top' being oriented away from the ground and 'bottom' being oriented towards the ground. The upper end is located at the top and the lower end is located at the bottom.

[0028] Vertical means that which is parallel to the direction of gravity given in particular by the plumb line, and horizontal means that which is perpendicular to the vertical. The top and bottom are vertically opposite.

[0029] Transverse means a direction perpendicular to a longitudinal direction. A transverse section is a section perpendicular to the longitudinal axis.

[0030] A parameter "approximately equal to / greater than / less than" or "of the order of" a given value means that this parameter is equal to / greater than / less than the given value, to within 10% or even 5% of that value.

[0031] For the purposes of this disclosure, the expression "A and / or B" means (A), (B) or (A and B). For the purposes of this disclosure, the expression "A, B and / or C" means (A), (B), (C), (A and B), (A and C), (B and C), or (A, B and C).

[0032] The upstream and downstream, the inlet, the outlet, at a given point are taken in reference to the direction of fluid flow.

[0033] The term "fluidically connected" or "in fluidic connection" means when a line provides a connection through or in which a fluid flows.

[0034] In the present description, the expression "A fluidically connected to B" is synonymous with "A is in fluidic connection with B" and does not necessarily mean that there is no component between A and B. Thus, these expressions refer to a fluidic connection between two elements, this connection being either direct or indirect. This means that it is possible that between a first element and a second element that are fluidically connected, a fluid path exists through one or more conduits, possibly an additional organ.

[0035] Conversely, the term "fluidically connected directly" refers to a direct fluidic connection between two elements. This means that between a first element and a second element that are fluidically connected directly, no other element is present, other than a conduit or several conduits.

[0036] The expressions "arranged on" or "on" are synonymous with "fluidly connected to".

[0037] Hot, cold, cooled means a relative temperature with respect to another point in the system.

[0038] The system according to the invention consists of adding an additional thermal storage unit 400 in addition to a Carnot battery.

[0039] The principle of a Carnot battery is to ensure the storage of electricity in the form of heat and then to release it in the form of electricity.

[0040] Carnot batteries were developed for the storage of electricity produced by intermittent energy sources, for example solar or wind energy, and for which electricity production is out of sync with electricity needs.

[0041] The Carnot battery includes an electricity-to-heat conversion module 100, a thermal heat storage module 200, and a heat-to-electricity conversion module 300.

[0042] The electricity-to-heat conversion module 100 includes any type of system enabling this conversion, such as, for example, an electric resistance or a heat pump or a combination of systems.

[0043] The thermal storage module 200 stores the heat produced by the conversion module 100 until it is converted into electricity as needed. The thermal storage module 200 is in thermal conduction with the electricity-to-heat conversion module 100. Thermal conduction occurs, for example, directly by heating the fluid circuit 201 with an electric resistance or by a heat exchanger ensuring heat transfer between the two modules.

[0044] The thermal storage module 200 can include any type of thermal storage, sensible or latent, particularly by PCM. Preferably, the thermal storage module 200 includes a fluidic circuit 201 for receiving a heat transfer fluid. The most commonly used heat transfer fluids in Carnot batteries are molten salts. For example, molten salts include HITEC (53% KNO3, 40% NaNO2, 7% NaNO3) or Solar Sait (40% KNO3, 60% NaNO3) for operating temperatures between 200 °C and 550 °C. Preferably, the thermal storage module 200 operates with molten salts. It operates at pressures very slightly above atmospheric pressure to ensure the inerting of the tank heads 202 and 203. The electricity-to-heat conversion module 100 thus heats the molten salts circulating in the fluid circuit 201. The thermal storage module 200 includes a cold tank 202 for storing cold molten salts and a hot tank 203 for storing hot molten salts. The thermal storage module 200 also includes a pump 204, and optionally a second pump 205, to ensure the circulation of the molten salts throughout the fluid circuit 201.

[0045] The Carnot battery also includes an interface heat exchanger 304 arranged at the interface between the thermal storage module 200 and the heat-to-electricity conversion module 300. The interface heat exchanger 304 is a heat exchanger that transfers thermal energy from the thermal storage module 200 to the heat-to-electricity conversion module 300. The interface heat exchanger 304 is thus traversed by the fluid circuit 201 and the steam cycle 301 of the heat-to-electricity conversion module 300 described below. The interface heat exchanger 304 is, for example, a salt / water-steam heat exchanger. The interface heat exchanger 304 is therefore called a steam generator since its purpose is to produce steam in the steam cycle 301.

[0046] The interface exchanger 304 is advantageously arranged downstream of the hot tank 203. The interface exchanger 304 is advantageously arranged upstream of the cold tank 202. Preferably, in the case where the system includes a charge exchanger 405, the interface exchanger 304 is arranged upstream of the charge exchanger 405 on the fluid circuit 201.

[0047] Conventionally, the Carnot battery is charged, when electricity prices are low, by pumping "cold" salt into the cold tank 202, heating it with the help of the electricity-to-heat conversion module 100, and then sending it into the hot tank 203. The cold tank 202 and the hot tank 203 are insulated so as to limit losses and thus retain the heat for many hours.

[0048] Conventionally, the discharge is carried out on demand according to a need of the electrical network and / or high resale tariffs by pumping salt into the hot tank 203, circulating it in the interface exchanger 304 and then sending it back into the cold tank 202. This makes it possible to produce steam to power a turbine 302 and thus produce electricity.

[0049] The fluidic circuit 201 provides the fluidic connection between the various components of the thermal storage module 200. More preferably, the fluidic circuit provides the fluidic connection from the cold tank 202 to the electricity-to-heat conversion module 100, then to the hot tank 203, and then to the heat exchanger. interface 304 then to the cold tank 202. Advantageously, the fluid circuit 200 includes a pump 204 and optionally a pump 205, the pumps being arranged so as to ensure the circulation of the molten salts throughout the fluid circuit 201. By way of example, as illustrated in all the figures, the pump 204 is arranged between the outlet of the cold tank 202 and the electricity-to-heat conversion module 100 and the pump 205 is arranged between the outlet of the hot tank 203 and the interface exchanger 304.

[0050] From a fluid connection point of view, the cold tank 202 is fluidically connected, preferably directly, to the pump 204 by the fluid connection 2001, ensuring the circulation of cold molten salts from the cold tank 202 to the pump 204. The pump 204 is fluidly connected, preferably directly, to the electricity-to-heat conversion module 100 by the fluid connection 2002, ensuring the circulation of cold molten salts from the pump 204 to the electricity-to-heat conversion module 100. The electricity-to-heat conversion module 100 is fluidly connected, preferably directly, to the hot tank 203 by the fluid connection 2003, ensuring the circulation of hot molten salts from the electricity-to-heat conversion module 100 to the hot tank 203.The hot tank 203 is fluidly connected, preferably directly, to the pump 205 via the fluid connection 2004, ensuring the circulation of hot molten salts from the hot tank 203 to the pump 205. The pump 205 is fluidly connected, preferably directly, to the interface heat exchanger 304 via the fluid connection 2005, ensuring the circulation of hot molten salts from the pump 205 to the interface heat exchanger 304. The interface heat exchanger 304 is fluidly connected to the cold tank 202 via the fluid connection 2006, ensuring the circulation of cold molten salts from the interface heat exchanger 304 to the cold tank 202, either directly or indirectly through a charge exchanger 405 described below, depending on the embodiment.

[0051] The heat-to-electricity conversion module 300 comprises a steam cycle 301 and at least one turbine 302 arranged on the steam cycle 301. The steam cycle 301 is designed to receive water and steam. The steam cycle 301 advantageously includes a pump 305 ensuring the circulation of the water and steam as well as the pressurization of the water in the steam cycle 301. The steam cycle 301 is arranged in thermal connection with the fluid circuit 201 of the thermal storage module 200 via the interface heat exchanger 304. Conventionally, the steam cycle includes a condenser 306 arranged downstream of the turbine 302. The condenser 306 is designed to condense the expanded steam exiting the turbine 302.

[0052] The steam cycle 301 is intended for the circulation of steam to supply the turbine 302 in which the steam will be expanded, ensuring, by means of a generator 303 associated, the production of electricity from the heat stored in the thermal storage module 200.

[0053] The working pressure of the steam cycle 301 depends on the temperature of the hot salt, but also on the conditions imposed by the turbine 302 according to its design. For example, the pressure of the steam cycle is between 100 and 200 bar.

[0054] In the steam cycle 301, the interface heat exchanger 304 is fluidically connected, preferably directly, to the turbine 302 by a fluidic connection A, ensuring the circulation of the steam produced in the interface heat exchanger 304 to the turbine 302 to supply it with steam. The turbine 302 is fluidly connected, preferably directly, to the condenser 306 by a fluidic connection B, ensuring the circulation of the expanded steam exiting the turbine 302 to the condenser 306 for the condensation of this expanded steam. The condenser 306 is fluidically connected, for example as illustrated in the figures directly, to a pump 305 by a fluidic connection C ensuring the circulation of the condensed water from the outlet of the condenser 306 to the pump 305. According to another possibility not illustrated, a degasser type tank can be arranged between the condenser 306 and the pump 305 on the fluidic connection C.The pump 305 is fluidically connected, preferably directly, to the interface exchanger 304 by a fluidic connection D ensuring the circulation of pressurized water towards the interface exchanger 304.

[0055] Preferably, the fluid circuit 201 of the thermal storage module 200 and the steam cycle 301 of the heat-to-electricity conversion module 300 are fluidically distinct. This means that the fluid circuit 201 and the steam cycle 301 do not have any fluidic communication. Similarly, if the heat-to-electricity conversion module 100 includes a fluid circuit, then this circuit is also fluidically distinct from the fluid circuit 101 and the steam cycle 301.

[0056] Preferably, the fluidic circuit 201 is a closed circuit.

[0057] Preferably, the steam cycle 301 is a closed circuit in the sense that it does not does not include external water or steam supply for preheating and / or maintaining the temperature of the 302 turbine. A water supply may only be provided as a supplement to compensate for any blowdowns.

[0058] In a particular application of the invention, the steam cycle 301 and the turbine 302 are part of a power plant which uses heat to generate steam and then power a turbine such as, for example, a coal-fired power plant, a nuclear power plant, an incineration plant or others.

[0059] The system includes an additional thermal storage unit 400. The additional thermal storage unit 400 is fluidly connected to the cycle steam 301. The additional thermal storage unit 400 includes at least one thermal storage device and a set of fluid connections intended to receive water in the liquid state and / or in the vapor state to ensure the fluid connection of the thermal storage device on the steam cycle 301.

[0060] The additional thermal storage unit 400 is separate from the thermal storage module 200 of the Carnot battery.

[0061] The additional thermal storage unit 400 allows a portion of the thermal energy stored in the Carnot battery to be used to produce steam and store its thermal energy in the additional thermal storage unit 400 and then release it to return thermal energy to the steam cycle 301 and more particularly to the turbine 302.

[0062] The additional thermal storage unit 400 makes it possible to preheat and / or maintain the temperature of all or part of the steam cycle 301, and more particularly of the turbine 302, using the thermal energy stored in the Carnot battery. Advantageously, the system according to the invention does not include an external steam supply to the Carnot battery. The additional thermal storage unit 400 makes it possible to release a low thermal power over a long period, thus ensuring satisfactory preheating and / or temperature maintenance.

[0063] The discharge of the Carnot battery's thermal storage module 200 is carried out to produce electricity when the power grid is energized. This allows the system to take advantage of favorable electricity buyback rates, but implies discontinuous operation. The thermal storage module 200, particularly the molten salt storage module, is not designed for low power output; therefore, it is shut down during periods of electricity production shutdown, and the steam cycle cools down. However, the requirements of the power grid necessitate that electricity production start quickly after the signal is given, which is not possible if the steam cycle is cold. The additional thermal storage unit 400 allows the system to preheat and / or maintain the temperature of all or part of the steam cycle 301.For example, starting a cold turbine can take up to 6 hours, while starting a heated turbine takes less than 2 hours. For example, the turbine is maintained at a temperature between 300°C and 500°C.

[0064] According to one possibility, the system includes a buffer tank 500 for storing steam from the steam cycle 301. The buffer tank 500 is fluidically connected to the steam cycle 301 by a fluid supply connection 501 from the buffer tank. The fluid supply connection 501 is advantageously connected downstream of the turbine 302, preferably directly downstream.

[0065] The buffer tank 500 is fluidically connected to the additional thermal storage unit 400 via the return fluid connection 402, ensuring filling water in the additional thermal storage unit 400 from the buffer tank 500 when there is a discharge of thermal energy through the fluid connection 401 for the benefit of the steam cycle 301. According to one possibility, a pump 406 is arranged on the return fluid connection 402 to ensure the circulation of the fluid in the connection.

[0066] The buffer tank 500 is fluidically connected to the additional thermal storage unit 400 by the evacuation fluid connection 404 ensuring the evacuation of water from the additional thermal storage unit 400 to the buffer tank 500 when the thermal storage unit 400 is being charged.

[0067] The buffer tank 500 is fluidically connected to the additional thermal storage unit 400 by the fluidic charging connection 403 ensuring the supply of water from the buffer tank 500 to the charge exchanger 405 by a first part 403a and then the supply of the thermal storage unit by the steam produced by the charge exchanger 405 through a second part 403b of the fluidic charging connection.

[0068] According to a preferred embodiment, the buffer tank 500 is a thermocline thermal storage tank that allows for the storage of hot and cold fluids in the same tank, but separated by a temperature gradient (stratification). Advantageously, the buffer tank 500 can store the expanded steam from the turbine 302 for use in charging the thermal storage device of the supplementary thermal storage unit 400. It can also store water from the thermal storage device of the supplementary thermal storage unit 400 when the latter is under load and the steam supplied to the device is converted into water following the storage of its thermal energy in the thermal storage device. The buffer tank 500 also provides water to the thermal storage device when it is in discharge mode and transfers heat to the steam cycle.

[0069] The buffer tank 500 thus has the advantage of allowing greater independence between the steam cycle and the thermal storage device, particularly for the charging stage, during which it is not necessary for the steam cycle 301 to be in operation, or conversely, when the steam cycle 301 is in operation, there is necessarily a charge on the storage device.

[0070] The additional thermal storage unit 400 includes a fluidic feed connection 401 to the turbine 302. The fluidic feed connection 401 originates from the thermal storage device and is fluidically connected to the steam cycle 301, advantageously upstream of the turbine 302 so as to supply the steam cycle 301 with steam, particularly when the thermal storage module of the Carnot battery is charging or stopped. The fluidic feed connection 401 ensures the fluidic connection of the thermal storage device to the steam cycle 301. The supply fluidic connection 401 is either connected directly upstream of the turbine 302 to supply only the turbine 302, as illustrated in the figures, or upstream of the interface exchanger 304 so as to also maintain the temperature of the interface exchanger 304 and prevent the solidification of the molten salts in the exchanger when the thermal storage module of the Carnot battery is stopped and the molten salts are not circulating in the fluidic circuit 201.

[0071] The additional thermal storage unit 400 includes a return fluid connection 402. The return fluid connection 402 ensures the fluid connection of the steam cycle 301, advantageously downstream of the turbine 302, to the additional thermal storage unit 400.

[0072] According to one possibility illustrated in the figures, the return fluid connection 402 is connected to the steam cycle 301 indirectly downstream of the turbine 302. According to this possibility, the system includes a buffer tank 500 arranged on the return fluid connection 402 between the steam cycle 301 and the additional thermal storage unit 400.

[0073] According to another possibility not illustrated, the return fluid connection 402 is connected directly to the steam cycle 301 downstream of the condenser 306, and possibly preferably downstream of the pump 305, so as to allow the return of the condensed water, rather than the expanded steam to the thermal storage device in order to take advantage of the large exchange coefficient during the evaporation of the water.

[0074] The supply fluid connection 401 and the return fluid connection 402 form a pair of preheating fluid connections; these are the connections in operation during a preheating and / or temperature maintenance step of all or part of the steam cycle 301, more precisely of the turbine 302.

[0075] The additional thermal storage unit 400 includes a charging fluid connection 403. The charging fluid connection 403 provides the fluid connection from the steam cycle 301 to the thermal storage device. The charging fluid connection 403 originates from the steam cycle 301 downstream of the turbine 302.

[0076] According to an embodiment not illustrated, the fluidic load connection 403 originates from the steam cycle downstream of the turbine 302, preferably downstream of the condenser 306, and even more preferably downstream of the pump 305, preferably upstream of the interface heat exchanger 304. The fluidic load connection 403 includes a branch connection to the steam cycle 301, which is preferably made to the fluidic connection D of the steam cycle 301. Preferably, the branch connection is arranged downstream of the pump 305 and upstream of the interface heat exchanger 304. According to this embodiment, the fluidic load connection 403 ensures a fluidic connection indirect between the steam cycle 301 and the thermal storage device, preferably via the charge heat exchanger 405 described below.

[0077] According to an embodiment illustrated in the figures, the fluidic load connection 403 is indirectly derived from the steam cycle 301 by being connected to the buffer tank 500, which is itself fluidically connected to the steam cycle 301 by the fluidic connection 501. The fluidic load connection 403 allows the additional thermal storage unit 400 to be supplied via the load heat exchanger 405 from the buffer tank 500.

[0078] According to an aspect not illustrated, the fluidic load connection 403 originates from the steam cycle 301 downstream of the turbine 302, preferably by drawing from the turbine 302. The connection of the fluidic load connection 403 to the steam cycle 301 is made at the turbine 302. According to this aspect, the fluidic load connection 403 ensures a direct fluidic connection between the steam cycle 301 and the additional thermal storage unit 400.

[0079] The additional thermal storage unit 400 includes a fluidic discharge connection 404.

[0080] According to an illustrated possibility, the discharge fluid connection 404 provides the fluid connection from the additional thermal storage unit 400 to the buffer tank 500. This discharge fluid connection 404 allows the discharge of water from the thermal storage device to the buffer tank 500 when the thermal storage device receives steam from the steam cycle 301 via the charge fluid connection 403.

[0081] According to an aspect not shown, the discharge fluid connection 404 provides the fluid connection from the additional thermal storage unit 400 to the steam cycle 301. This discharge fluid connection 404 allows water to be discharged from the thermal storage device to the steam cycle 301 when the thermal storage device receives steam from the steam cycle 301 via the feed fluid connection 403. By way of example, the discharge fluid connection 404 is fluidically connected to the steam cycle 301 downstream of the turbine 302 so as not to affect the operation of the turbine 302. Preferably, the discharge fluid connection 404 is fluidly connected to the steam cycle 301 downstream of the condenser 306. Preferably, the discharge fluid connection 404 is fluidly connected to the fluid connection D of the steam cycle 301.The charging fluid connection 403 and the discharge fluid connection 404 form a pair of charging fluid connections. These are the connections in operation during a charging stage of the thermal storage device of the supplementary thermal storage unit 400.

[0082] Advantageously, the fluidic supply connection 402, the fluidic connection The return 401, the charging fluid connection 403, and the discharge fluid connection 404 are separate fluid connections. The system comprises at least four, and possibly at least five, fluid connections, ensuring fluid circulation between the thermal storage device of the supplementary thermal storage unit 400 and the steam cycle 301 of the heat-to-electricity conversion module, and possibly the buffer tank 500.

[0083] At least one thermal storage device of the additional thermal storage unit 400 may be a latent and / or sensible storage device. The at least one thermal storage device is selected from a phase change material (PCM) thermal storage system 4001, a vapor accumulator 4002, a solid air sensitive storage system 4003, or a thermocline system.

[0084] A thermal storage system by MCP 4001 that can be used as a thermal storage device for the additional thermal storage unit 400 is illustrated in [Fig.1], and in Figures 4 and 5.

[0085] Preferably, the thermal storage system (TSS) by PCM is a shell-and-tube heat exchanger in which a tank, the shell, receives a phase change material (PCM). The tank is traversed by a bundle of tubes through which water flows in the liquid state and / or in the vapor state in fluidic connection with the steam cycle 301 and more specifically by the fluidic connections 401, 402, 403, 404 in fluidic connection with the tube bundle.

[0086] The phase change material is chosen according to the desired operating temperature. For example, sodium nitrate (NaNO3) can be used for a temperature around 300°C.

[0087] The use of a PCM thermal storage system (TSS) comprising a shell and tube heat exchanger offers the advantage of having the water in its liquid and / or vapor state separated from the PCM by the tube bundle. The pressurized elements thus consist solely of the tube bundle and two distributors at each end of the tubes. The shell containing the PCM operates at a pressure close to atmospheric pressure. Exploiting the latent heat of the PCM's phase change, preferably a solid / liquid PCM, makes it possible to store and release the steam with a small temperature variation. Thus, during release, the pressure and temperature of the produced steam remain very stable.

[0088] According to another alternative or cumulative possibility, the thermal storage device is a vapor accumulator 4002 as illustrated in [Fig.2], and in Figures 4 and 5.

[0089] A 4002 steam accumulator exhibits very good responsiveness, enabling the steam to be discharged quickly after the instruction is transmitted. With a steam accumulator 2002, steam is delivered in a few seconds, or even instantaneously, into the fluidic supply connection 401.

[0090] The steam accumulator 4002 is in fluidic connection with the steam cycle 301, more precisely through the fluidic connections 401, 402, 403, 404.

[0091] According to another alternative or cumulative possibility to the two preceding ones, the thermal storage device of a sensible heat storage system. As a preferred example, the sensible heat storage system 4003 is made in a solid material such as high-temperature concrete or ceramics. This possibility is illustrated in [Fig. 3]. This type of sensible heat storage in a solid material comprises a solid material enclosure and a steam / air heat exchanger. Air circulates in the heat exchanger and recovers its thermal energy. The heated air then circulates in contact with the solid material so as to store the heat in the solid material. This type of storage has the advantage of using inexpensive storage materials, posing no risks (chemical, fire, etc.) and capable of reaching very high temperatures, up to 1000 °C.The sensible heat storage system 4003 is in fluidic connection with the steam cycle 301, more specifically through fluidic connections 401, 402, 403, 404 and a water-steam / air heat exchanger 4003a.

[0092] According to another example not illustrated, the sensible heat storage system is done in a liquid material such as water, thermal oil or molten salt, the storage is called thermocline thermal storage.

[0093] The additional thermal storage unit 400 comprises one or more thermal storage devices. Several combinations of the thermal storage devices described above can be envisaged. Some examples of combinations of thermal storage devices are illustrated in Figures 4 and 5. A combination of a PCM SST 4001 and a vapor accumulator 4002, in [Fig. 4], a combination of a PCM SST 4001, a vapor accumulator 4002 and a solid sensible heat storage system 4003 in [Fig. 5].

[0094] Advantageously, the SST by MCP 4001 and the steam accumulator 4002 are arranged in parallel for the charging fluid connections 403 and supply 401 and in series for the return fluid connections 402 and discharge 404 as illustrated in figures 4 and 5.

[0095] In [Fig. 5], advantageously, the SST by MCP 4001 and the steam accumulator 4002 are arranged in parallel for the charging fluid connections 403 and the supply fluid connections 401 and in series for the return fluid connections 402 and the discharge fluid connections 404, and the solid sensible heat storage system 4003 is arranged in series with the two other thermal storage devices, the SST by MCP 4001 and the steam accumulator 4002. A derivative of this heat storage system The 4003 solid sensitive sensor can be used. In this case, we return to an operation identical to that of [Fig.4].

[0096] According to the invention, at least one thermal storage device is fluidically connected indirectly to the steam cycle to ensure its charge. More specifically, the fluidic charge connection 403 supplies steam to the storage device of the additional thermal storage unit 400 through the heat exchanger 405. This embodiment can be combined with the presence of a buffer tank 500 as detailed below or may be provided without the buffer tank 500 with a fluidic charge connection 403 connected to the steam cycle 301.

[0097] The thermal storage device of the additional thermal storage unit 400 is connected to the steam cycle 301 via the feed fluid connection 403, which passes through a feed heat exchanger 405. The feed heat exchanger 405 is arranged on the molten salt fluid circuit 201 and on the feed fluid connection 403 so as to ensure the exchange of thermal energy from the thermal storage module 200 of the Carnot battery to the additional thermal storage unit 400, and more specifically to the feed fluid connection 403. The feed heat exchanger 405 has a lower capacity than the interface heat exchanger 304. According to this first embodiment, the feed fluid connection 403 originates from the buffer tank 500, which is itself connected for its supply to the steam cycle 301 downstream of the turbine 302 via the fluid connection 501.In this embodiment, the fluid connection for the load 403 comprises a first part 403a and a second part 403b. The first part of the load connection 403a extends between the buffer tank 500 and the load exchanger 405. This first part of the fluid connection for the load 403a ensures the circulation of water from the buffer tank 500 to the load heat exchanger 405. The load heat exchanger 405 transforms the water supplied by the first part of the fluid connection for the load 403a into steam. The second part of the fluid connection for the load 403b extends between the load heat exchanger 405 and the thermal storage device. This second part of the fluid connection for the load 403b ensures the circulation of steam from the load heat exchanger 405 to the thermal storage device.The steam produced in the heat exchanger 405 is transported to the thermal storage device by the second part of the fluidic load connection 403b. The connection between the steam cycle and the thermal storage device is indirect with respect to the load.

[0098] According to a second embodiment that can be combined with the first embodiment, the fluidic supply connection 401 originates from the device of The thermal storage unit is fluidically connected to the steam cycle 301, advantageously upstream of the turbine 302 and preferably downstream of the interface heat exchanger 304, so as to supply steam to the steam cycle 301. The supply fluid connection 401 extends between the storage unit and the branch connection 4011 on the steam cycle, arranged according to a possibility on the fluid connection A.

[0099] According to a third alternative embodiment to the second embodiment, and which can also be combined with the first embodiment, the supply fluid connection 401 originates from the thermal storage device and is fluidically connected to the steam cycle 301, advantageously upstream of the turbine 302 and preferably upstream of the interface heat exchanger 304 so as to supply the steam cycle 301 with steam. The supply fluid connection 401 extends between the storage device and the branch 4011 on the steam cycle arranged on the fluid connection D. The branch 4011 of the supply fluid connection is arranged downstream of a possible branch of the charge fluid connection 403 on the fluid connection D of the steam cycle.In this fourth embodiment, the supply fluid connection 401 allows steam to circulate through the interface heat exchanger 304 when the molten salt fluid circuit is stopped. This arrangement thus limits the risk of molten salts crystallizing in the interface heat exchanger and damaging it, while ensuring a steam supply to the turbine 302.

[0100] Figure 4 is detailed below with regard to the arrangement of the devices Thermal storage. The charging fluid connection 403 provides the steam supply fluid connection to the two thermal storage devices 4001 and 4002 of the additional thermal storage unit 400. The fluid connection 403 includes a bypass fluid connection 403d for supplying a second storage device in parallel, as illustrated in the example in [Fig. 4]. The fluid connection 403 supplies the thermal storage system via MCP 4001, and the bypass fluid connection 403d provides the bypass from the fluid connection 403 to the second storage device, i.e., the steam accumulator 4002. The supply fluid connection 401 also includes a bypass fluid connection 40Id providing the bypass from the second storage device, the steam accumulator 4002, to the fluid connection 401.Advantageously, the MCP 4001 thermal storage system is fluidically connected to the steam accumulator 4002 by an additional return fluid connection 402a and an additional discharge fluid connection 404a. More specifically, the additional return fluid connection 402a provides the fluid connection from the MCP 4001 thermal storage system to the steam accumulator 4002. The steam accumulator 4002. The additional discharge fluid connection 404a provides the fluid connection from the steam accumulator 4002 to the thermal storage system via MCP 4001. The thermal storage system via MCP 4001 is not directly connected to the steam cycle 301 with respect to the return fluid connection and the discharge fluid connection, but indirectly through the steam accumulator 4002. The steam accumulator 4002 is fluidically connected to the steam cycle via the buffer tank 500 by the return fluid connection 402 and the discharge fluid connection 404. The steam accumulator 4002 is fluidly connected to the steam cycle by the bypass feed fluid connection 401d and the bypass charge fluid connection 403d.

[0101] The [Fig.5] is detailed below with regard to the arrangement of the thermal storage devices. The fluid connection 403 comprises the first part of the fluid connection 403a, which connects the steam cycle 301 through the buffer tank 500 to the heat exchanger 405, and the second part of the fluid connection 403b, which connects the heat exchanger 405 to the thermal storage device, and more specifically to the PCM thermal storage system 4001. The system includes, arranged on this fluid connection 403b, a heat exchanger 4003a that provides heat exchange between the steam circulating in the fluid connection 403b and air intended to circulate in the sensitive storage device 4003. The fluid connection 403b includes a bypass fluid connection 403d that provides the fluid connection between the fluid connection 403 and the steam accumulator 4002.The feed fluid connection 401 extends from the MCP thermal storage system 4001 to the steam cycle 301. The heat exchanger 4003a is also arranged on this feed fluid connection 401 to ensure the recovery of thermal energy stored in the sensitive storage device 4003. A bypass feed fluid connection 401d provides the connection between the steam accumulator 4002 and the feed fluid connection 401. The return 402 and discharge 404 fluid connections are similar to those described with reference to [Fig. 4].

[0102] According to another aspect, the invention relates to a method of heating and / or maintaining the heat of all or part of the steam cycle 301 specifically of the turbine of a system as described below.

[0103] The heating and / or temperature maintenance process includes a charging step for the thermal storage device of the additional thermal storage unit 400. This charging step allows thermal energy to be stored in the thermal storage device of the additional thermal storage unit 400. for use in preheating and maintaining temperature.

[0104] The charging stage includes the circulation of steam from the steam cycle 301 through the buffer tank 500 to the thermal storage device. The charging stage includes a closed-loop steam circulation from the steam cycle 301 to the thermal storage device via the buffer tank 500.

[0105] Advantageously, the charging step takes place when the thermal storage module 200 of the Carnot battery supplies thermal energy to the heat-to-electricity transformation module 300 and more particularly to the steam cycle 301. The charging step is therefore advantageously carried out simultaneously with the production of electricity and with the thermal energy stored in the Carnot battery.

[0106] During the charging stage, steam, in particular the thermal energy of the steam, is supplied from the buffer tank 500 to the thermal storage device. During this stage, water is discharged from the thermal storage device through the fluid connection 404. The discharged water is returned to the buffer tank 500.

[0107] According to a first embodiment illustrated in Figures 1 to 5, the steam exiting the turbine 302 is collected, for example at the fluidic connection B, by a fluidic connection 501 to be stored in a buffer tank 500. When it is necessary to charge the additional storage unit 400, the steam present in the buffer tank 500 is transferred via the charging fluidic connection 403, more specifically the first part 403a, to the charging heat exchanger 405. The heat exchanger 405 produces the steam which is then transferred to the additional thermal storage unit 400 via the fluidic connection 403, more specifically the second part of the fluidic connection 403b. This embodiment allows the system according to the invention to be adapted to different types of steam cycle 301 even if the turbine 302 does not have a withdrawal point.

[0108] The method according to the invention includes a preheating and / or temperature maintenance step for all or part of the steam cycle 301, and more specifically for the turbine 302. Advantageously, the preheating and / or temperature maintenance step takes place when the thermal storage module 200 of the Carnot battery is not releasing thermal energy to the electricity generation module. Therefore, the preheating and / or temperature maintenance step occurs when there is no thermal energy being released from the thermal storage module 200 of the Carnot battery. This preheating and / or temperature maintenance step allows the thermal energy in the form of steam from the thermal storage device of the additional thermal storage unit 400 to be released to the steam cycle 301, and in particular to the turbine 302, when the latter is not being used for electricity generation.The circulation of steam from the storage device to the steam cycle 301 is done via the fluidic feed connection. 401.

[0109] During the preheating and / or temperature maintenance stage, expanded water is brought from the buffer tank 500 to the thermal storage device via the fluid connection 402.

[0110] According to the second embodiment, the preheating and / or temperature maintenance step allows steam to be supplied to the turbine 301, the supply fluid connection 401 opening upstream of the turbine 302 and preferably downstream of the interface heat exchanger 304.

[0111] According to the third embodiment, the preheating and / or temperature maintenance step allows steam to be supplied to the turbine 301 and the interface heat exchanger 304, the supply fluid connection 401 opening upstream of the turbine 302 and upstream of the interface heat exchanger 304.

[0112] According to the invention, the process includes a step of converting electricity into heat by the electricity-to-heat conversion module 100. This electricity-to-heat conversion step is carried out when the electricity produced, in particular by an intermittent source for example which is not used immediately or which is cheap, is therefore converted into heat.

[0113] The process includes a heat storage step using the heat produced by the electricity-to-heat conversion module 100. The heat storage step is carried out by the thermal storage module 200 in thermal connection with the electricity-to-heat conversion module 100. The heat produced by the electricity-to-heat conversion module 100 is transferred to the thermal storage module 200. The heat is then stored as described above with reference to the thermal storage module 200.

[0114] The process includes a step of converting stored heat into electricity. This step of converting stored heat into electricity takes place when there is a demand for electricity. This step of converting stored heat into electricity includes releasing the heat stored in the thermal storage module 200 to the stored heat-to-electricity conversion module 300, and more specifically to its steam cycle 301.

[0115] List of references 100. Electricity-to-heat conversion module 200. Thermal storage module for the heat produced 201. Fluid circuit of molten salts 202. Cold tank 203. Hot tank 204. First Pump 205. Second Pump 2001. Fluidic connection between the outlet of the cold salt tank 202 and the inlet of the pump 204. 2002. Fluidic connection between the outlet of pump 204 and the electricity-to-heat conversion module 100 2003. Fluidic connection between the electricity-to-heat transformation module 100 and the inlet of the hot salt tank 203. 2004. Fluid connection between the outlet of the hot salt tank 203 and the inlet of the pump 205 2005. Fluid connection between the outlet of pump 205 and the inlet of the interface heat exchanger 304 2006. Fluidic connection between the outlet of the interface heat exchanger 304 and the inlet of the cold salt tank 202. 2006a. Fluidic connection between the outlet of the interface heat exchanger 304 and the inlet of the load heat exchanger 405 2006b. Fluidic connection between the outlet of the charge heat exchanger 405 and the inlet of the cold salt tank 202. 300. Heat-to-electricity conversion module 301. Steam Cycle 302. Turbine 303. Electric Generator 304. Interface heat exchanger for thermal storage module and steam cycle 305. Pump 306. Condenser 400. Additional thermal storage unit 4001. SST by MCP 4002. Steam accumulator 4003. Solid Sensitive Storage System 4003a. Air / steam exchanger 401. Turbine feed fluid connection 40Id. Bypass of the turbine feed fluid connection 4011. Fluidic supply connection tap 402. Fluid return connection 402a. Fluid return connection between the steam accumulator and the SST via MCP 403. Fluidic charging connection 403a. First part of the fluidic charging connection between the buffer tank and the interface exchanger 403b. Second part of the fluidic charge connection between the interface exchanger and a thermal storage device 403d. Derivation of the fluidic charge connection 404. Fluidic drainage connection 404a. Fluidic discharge connection between the steam accumulator and the SST by MCP 405. Charge heat exchanger 406. Pump 407. Pump 500. Buffer tank 501. Fluid connection for supplying the buffer tank A. Fluidic connection between the outlet of the interface heat exchanger 304 and the inlet of the turbine 302 B. Fluidic connection between the outlet of turbine 302 and the inlet of condenser 306 C. Fluid connection between the outlet of condenser 300 and the inlet of pump 305 D. Fluid connection between the outlet of pump 305 and the inlet of interface heat exchanger 304

Claims

Demands

1. A system comprising a Carnot battery including an electricity-to-heat conversion module (100), a thermal storage module for the heat produced (200) by the electricity-to-heat conversion module (100), and a heat conversion module (300) for converting the heat (300) from the storage module into electricity, the heat conversion module (300) from the storage module into electricity including a steam cycle (301) and a turbine (302) arranged on the steam cycle (301) for expanding the steam for the purpose of electricity production, characterized in that the system includes an additional thermal storage unit (400) fluidly connected to the steam cycle (301) and intended for storing steam from the steam cycle (301) and separate from the thermal storage module (200) of the Carnot battery, the additional thermal storage unit (400) including • at least one thermal storage device, • a buffer tank (500) and a fluid connection (501) for supplying the buffer tank (500) arranged between the steam cycle (301), downstream of the turbine (302), and the buffer tank (500) allowing the circulation of steam and / or water from the steam cycle (301) to the buffer tank (500), • a pair of preheating fluid connections comprising • a fluid connection (401) for supplying steam to the turbine (302) arranged between the thermal storage device and the steam cycle (301) upstream of the turbine (302) to ensure the fluid connection from the thermal storage device to the steam cycle (301) so as to provide preheating and / or temperature maintenance of all or part of the steam cycle (301) and preferably at least of the turbine (302), and • a return fluid connection (402) arranged between the buffer tank (500) and the thermal storage device to ensure the fluid connection from the buffer tank (500) to the thermal storage device so as to ensure the return of the expanded steam and / or water at the outlet of the buffer tank (500) to the thermal storage device, • a pair of charging fluid connections comprising • a charging fluid connection (403) arranged between the buffer tank (500) and the thermal storage device to ensure the fluid connection from the buffer tank (500) to the thermal storage device so as to charge the thermal storage device with thermal energy, and • an evacuation fluid connection (404) arranged between the storage device and the buffer tank (500) so as to ensure the circulation of water from the storage device to the buffer tank (500).

2. System according to claim 1 comprising a heat exchanger for charging (405) arranged on the thermal storage module (200) of the Carnot battery and on the fluidic charging conduit (403).

3. System according to any one of the preceding claims wherein the Carnot battery comprises an interface heat exchanger (304) arranged between the produced heat storage module (200) and the steam cycle (301) so as to ensure heat transfer from the heat storage module (200) to the steam cycle (301), the interface heat exchanger (304) being arranged on the steam cycle (301) upstream of the turbine (302), the turbine (301) supply connection (401) being connected to the steam cycle (301) downstream of the interface heat exchanger (304).

4. System according to any one of claims 1 to 3 wherein the Carnot battery comprises an interface heat exchanger (304) arranged between the produced heat storage module (200) and the steam cycle (301) so as to ensure heat transfer from the heat storage module (200) to the steam cycle (301), the interface heat exchanger (304) being arranged on the steam cycle (301) upstream of the turbine (302), the turbine (301) supply connection (401) being connected to the steam cycle (301) upstream of the interface heat exchanger (304).

5. System according to any one of the preceding claims in which the thermal storage device includes a phase change material (PCM) thermal storage system (TSS).

6. System according to any one of the preceding claims wherein the thermal storage device comprises a vapor accumulator (4002).

7. System according to any one of the preceding claims wherein the thermal storage device comprises a sensitive storage.

8. System according to any one of the preceding claims not comprising an external heat source other than the Carnot battery for the production of steam in the steam cycle (301).

9. System according to any one of the preceding claims wherein the steam cycle (301) and the turbine (302) are part of a coal-fired power plant.

10. System according to any one of the preceding claims in which the thermal storage module (200) for heat produced from the Carnot battery comprises a fluidic circuit (201) for receiving at least one molten salt and ensuring the fluidic connection between a cold tank (202) for storing the cold molten salt, a hot tank (203) for storing the hot molten salt, a pump (204), the electricity-to-heat conversion module (100), and an interface heat exchanger (304) through which the steam cycle (301) circulates.

11. Use of the system according to any one of the preceding claims to reuse a steam cycle (301) and a turbine (302) from a coal-fired power station.

12. A method for preheating and / or maintaining the temperature of a turbine of a system according to any one of claims 1 to 10 comprising a step of charging the thermal storage device of the additional thermal storage unit (400) comprising circulating steam to the thermal storage device from the buffer tank (500), and alternatively a step of preheating and / or maintaining the temperature of the turbine comprising circulating steam from the thermal storage device to the steam cycle (301).

13. A method according to the preceding claim comprising a stage of electricity production by the turbine (302), the charging stage of the

14. thermal storage device being carried out during this electricity production step. Method according to the preceding claim wherein the preheating and / or temperature maintenance step of the turbine (302) is carried out alternately with the electricity production step.

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