Carnot battery turbine thermal management system and method

Abstract

The invention relates to a system comprising a Carnot battery comprising a module for transforming electricity into heat, a module for thermal storage of the produced heat and a module for transforming the heat, the module for transforming the destored heat comprising a steam cycle and a turbine arranged on the steam cycle. The system comprises an additional thermal storage unit fluidically 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 - a thermal storage device, - a fluid connection for supplying steam to the turbine and a return fluid connection, - a load fluid connection and a discharge fluid connection.

Description

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 applies to all systems comprising a heat production unit coupled to a thermodynamic cycle for electrogenic purposes, for example nuclear power plants. The invention will find a particular application for the reuse of steam cycles in coal-fired power plants. STATE OF THE ART

[0002] The growing use of uncontrollable intermittent renewable energy sources is leading to a growing need to compensate for sudden fluctuations in production. In this area, thermal storage allows electricity to be stored in thermal form during periods of low demand, in order to release it during peaks in electricity consumption, with the aim of limiting the use of fossil fuel backup sources.

[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 that converts electricity into heat, then stores that heat, and finally converts that heat into electricity as needed.

[0005] At the same time, coal-fired electricity production is among the activities with the highest carbon footprint. According to ADEME, a coal-fired power plant emits around 1050 tCO2eq / kWh of electricity produced. To this end, European countries are aiming to phase out coal in the coming years as part of the fight against climate change.

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

[0007] The GIZ report "Repurposing existing coal-fired power plants into thermal storage plants for renewable power in Chile" presents the technical modifications required to use the water / steam cycle of a coal-fired power plant in a Carnot battery, as well as an economic analysis for the Chilean case.

[0008] However, this solution has the disadvantage of being less responsive. When the electricity grid operator requests a supply of electricity, 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] We know the document "Preheating procedure for fast start-up of a steam turbine from a cold state" which describes a preheating procedure to quickly start the cycle of a steam turbine. For this, several heat sources are identified: steam from an external source, electrical tracing or hot air. Steam as a heat source comes from an existing steam cycle, particularly based on the principle 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 to both supply steam and receive it, which multiplies the 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 involve maintaining a stable load on a turbine in operation throughout the preheating period, which is not necessarily compatible with network requirements.

[0010] There is therefore a need to propose a solution ensuring rapid and easy-to-implement 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 comprising a module for transforming electricity into heat, a module for thermal storage of the heat produced by the module for transforming electricity into heat, and a module for transforming the heat, destored from the storage module, into electricity, the module for transforming the heat destored from the storage module into electricity comprising a steam cycle and a turbine arranged on the steam cycle to expand the steam for the production of electricity, characterized in that the system comprises an additional thermal storage unit fluidically 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 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 making it possible to ensure the fluid connection of the thermal storage device to the steam cycle so as to ensure preheating and / or maintaining the temperature of all or part of the steam cycle and preferably at least of the turbine, and a return fluid connection arranged between the steam cycle downstream of the turbine and the thermal storage device making it possible to ensure the fluid connection of the steam cycle to the thermal storage device so as to ensure the return of the expanded steam and / or water at the turbine outlet to the thermal storage device, a pair of load fluid connections comprising a load fluid connection arranged between the steam cycle,preferably downstream of the turbine, and preferably the thermal storage device making it possible to ensure the fluidic connection of the steam cycle to the thermal storage device so as to charge the thermal storage device with thermal energy by the steam from the steam cycle, and a fluidic evacuation connection preferably arranged between the storage device and the steam cycle downstream of the turbine, so as to ensure the circulation of water from the storage device to the steam cycle.

[0012] The proposed invention makes it possible to overcome the constraints of the state of the art by using a thermal storage unit independent of the storage of the Carnot battery and dedicated to the function of preheating and / or maintaining the temperature of at least part of the steam cycle and in particular of 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 stopped in order to limit losses. In addition, the heat used comes from the Carnot battery which has been charged from the electricity of the network, when the latter is not under tension. This makes it possible to benefit from low, or negative, tariffs, or even surplus electricity, generally of renewable origin, and to avoid the use of fossil fuels.

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

[0014] According to one possibility, the system comprises a load heat exchanger arranged on the thermal storage module of the Carnot battery and on the load fluid line advantageously originating from the steam cycle indirectly fluidically connecting the steam cycle upstream of the turbine to the thermal storage device through the load heat exchanger.

[0015] According to this first embodiment, the indirect connection of the steam cycle to the storage unit via a load exchanger makes it possible to recover the thermal energy produced and stored in the Carnot battery to store it in the additional thermal storage unit which 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 makes it easier to implement the system in the case of reuse, or retrofit, of a steam cycle and a turbine. Indeed, this configuration does not require adding withdrawals to the turbine, the pressure, temperature and flow conditions of which must be compatible with the needs of the additional thermal storage unit.

[0016] According to another possibility, the fluidic charge line from the steam cycle fluidly connects the steam cycle directly to the thermal storage device, preferably by withdrawal at the turbine 302. According to this second embodiment, the direct connection of the steam cycle to the storage unit makes it possible to recover the thermal energy produced by the Carnot battery directly at the steam cycle. This configuration makes it possible to avoid the addition of a second exchanger, salt / water-steam, the steam being directly taken from the steam cycle and preferably from a turbine withdrawal.

[0017] According to another aspect, the system comprises a buffer tank arranged between the steam cycle and the additional thermal storage unit, and a buffer tank supply fluid connection arranged between the steam cycle, downstream of the turbine, and the buffer tank, the load fluid connection, the return fluid connection and the discharge fluid connection being fluidically connected to the buffer tank.

[0018] In one aspect, the invention relates to the use of the system as described below to reuse a steam cycle and a turbine of a coal-fired power plant.

[0019] 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 comprising the circulation of steam to the thermal storage device from the steam cycle, and alternatively a step of preheating and / or maintaining the temperature of the turbine comprising the circulation of steam from the thermal storage device to the steam cycle.

[0020] The method according to the invention makes it possible to use part of the heat from the operation of the Carnot battery to be stored in preparation for preheating and / or maintaining the temperature of all or part of the steam cycle, in particular when the release of the heat stored in the heat storage module is stopped. BRIEF DESCRIPTION OF THE FIGURES

[0021] The aims, objects, as well as the characteristics and advantages of the invention will emerge more clearly from the detailed description of an embodiment thereof which is illustrated by the following accompanying drawings in which: There Figure 1 represents a diagram of a first variant of the invention. The Figure 2 represents a diagram of a second variant of the invention in which the additional storage unit comprises two thermal storage devices: a thermal storage system by MCP and a steam accumulator. The Figure 3 represents a diagram of a third variant of the invention in which the additional storage unit comprises three thermal storage devices: a thermal storage system by MCP, a steam accumulator and a sensitive storage and the fluidic connection of charge 403 passes through the heat exchanger of charge 405. The Figure 4represents a diagram of a fourth variant of the invention in which the fluid supply connection 401 is connected upstream of the exchanger 304 on the steam cycle 301.

[0022] 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 to the scale of practical applications. DETAILED DESCRIPTION

[0023] Before commencing a detailed review of embodiments of the invention, optional features which may optionally be used in combination or alternatively are set out below: According to one example, the Carnot battery comprises an interface heat exchanger 304 arranged between the module for storing the produced heat 200 and the steam cycle 301 so as to ensure the 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 downstream of the interface heat exchanger 304;According to one example, the Carnot battery comprises an interface heat exchanger 304 arranged between the heat storage module 200 for the produced heat 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 power 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 comprises a thermal storage system (TSS) using a phase change material (PCM); According to one example, the thermal storage device comprises a steam accumulator; According to one example, the thermal storage device comprises 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 a coal-fired power plant, 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 comprises a fluid circuit 201 intended to receive at least one molten salt and ensuring the fluid connection between a cold reservoir 202 intended to store the cold molten salt, a hot reservoir 203 intended to store the hot molten salt, a pump 204, the electricity-to-heat transformation module 100, and an interface heat exchanger 304 through which the steam cycle 301 circulates;According to one example, the method comprises a step of producing electricity by the turbine, the step of charging the thermal storage device being carried out during this step of producing electricity; According to one example, the step of preheating and / or maintaining the temperature of the turbine is carried out alternately with the step of producing electricity.

[0024] For the remainder of the description, `top' and `bottom', or their derivatives, mean a quality of relative positioning of an element of the system or when it is functionally installed, the `top' being oriented away from the ground and the `bottom' being oriented towards the ground. The upper end is at the top and the lower end is at the bottom.

[0025] Vertical means that which is parallel to the direction of gravity given in particular by the plumb line and horizontal that which is perpendicular to the vertical. The top and the bottom being vertically opposed.

[0026] Transverse means a direction perpendicular to a longitudinal direction. A cross section is a section perpendicular to the longitudinal axis.

[0027] A parameter "substantially equal / greater / less than" or "of the order of" a given value means that this parameter is equal / greater / less than the given value, to within plus or minus 10%, or even plus or minus 5%, of this value.

[0028] 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).

[0029] Upstream and downstream, inlet, outlet, at a given point are taken in reference to the direction of circulation of the fluid.

[0030] "Fluidly connected" or "fluidically connected" means when a line provides a connection through or in which a fluid circulates.

[0031] 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 member between A and B. Thus these expressions are understood to mean a fluidic connection between two elements, this connection may or may not be direct. This means that it is possible that between a first element and a second element which are fluidically connected, a path of a fluid exists via one or more conduits, possibly an additional member.

[0032] Conversely, the term "fluidically connected directly" means a direct fluid 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.

[0033] The expressions "arranged on" or "on" are synonyms for "fluidically connected to".

[0034] Hot, cold, cooled means a temperature relative to another point in the system.

[0035] The system according to the invention consists of adding an additional thermal storage unit 400 in addition to a Carnot battery.

[0036] The principle of a Carnot battery is to ensure the storage of electricity in the form of heat and then to restore it in the form of electricity.

[0037] Carnot batteries were developed for storing electricity produced by intermittent energy sources, such as solar or wind energy, where electricity production is delayed compared to electricity needs.

[0038] The Carnot battery comprises an electricity-to-heat conversion module 100, a heat-to-heat storage module 200, and a heat-to-electricity conversion module 300.

[0039] The electricity-to-heat transformation module 100 includes any type of system allowing this transformation, such as, for example, an electrical resistance or a heat pump or a combination of systems.

[0040] The thermal storage module 200 of the heat makes it possible to store the heat produced by the transformation module 100 while waiting for its transformation into electricity according to needs. The thermal storage module 200 is in thermal conduction with the electricity transformation module into heat 100. The thermal conduction is done for example directly by the heating of the fluid circuit 201 by an electrical resistance or by a heat exchanger ensuring the thermal transfer between the two modules.

[0041] The thermal storage module 200 may comprise any type of thermal storage, sensible or latent, in particular by MCP. Preferably, the thermal storage module 200 comprises a fluid circuit 201 intended to receive a heat transfer fluid. The heat transfer fluids most used in Carnot batteries are molten salts. For example, the molten salts are 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 operating with molten salts operates at pressures very slightly above atmospheric pressure in order to ensure the inerting of the roofs of the reservoirs 202, 203. The electricity-to-heat transformation module 100 thus allows the heating of the molten salts circulating in the fluid circuit 201.The thermal storage module 200 comprises a cold reservoir 202 intended to store the cold molten salts and a hot reservoir 203 intended to store the hot molten salts. The thermal storage module 200 also comprises a pump 204 and possibly a second pump 205 to ensure the circulation of the molten salts throughout the fluid circuit 201.

[0042] The Carnot battery also comprises an interface exchanger 304 arranged at the interface between the thermal storage module 200 and the heat-to-electricity conversion module 300. The interface exchanger 304 is a heat exchanger ensuring the transfer of thermal energy from the thermal storage module 200 to the heat-to-electricity conversion module 300. The interface exchanger 304 is thus crossed by the fluid circuit 201 and the steam cycle 301 of the heat-to-electricity conversion module 300 described below. The interface exchanger 304 is for example a salt / water-steam exchanger. The interface exchanger 304 is thus called a steam generator since its purpose is to produce steam in the steam cycle 301.

[0043] The interface exchanger 304 is advantageously arranged downstream of the hot reservoir 203. The interface exchanger 304 is advantageously arranged upstream of the cold reservoir 202. Preferably in the case where the system comprises a load exchanger 405, the interface exchanger 304 is arranged upstream of the load exchanger 405 on the fluid circuit 201.

[0044] Conventionally, the charging of the Carnot battery is carried out, when electricity prices are low, by pumping “cold” salt into the cold reservoir 202, heating it using the electricity-to-heat transformation module 100, then sending it to the hot reservoir 203. The cold reservoir 202 and the hot reservoir 203 are insulated so as to limit losses and thus retain the heat for many hours.

[0045] Conventionally, the discharge is carried out on demand depending on a need of the electricity network and / or high resale prices by pumping salt into the hot reservoir 203, circulating it in the interface exchanger 304 then returning it to the cold reservoir 202. This makes it possible to produce steam in order to power a turbine 302 and thus produce electricity.

[0046] The fluid circuit 201 ensures the fluid connection between the different components of the thermal storage module 200. More preferably, the fluid circuit ensures the fluid connection from the cold reservoir 202 to the electricity-to-heat transformation module 100, then to the hot reservoir 203, then to the interface exchanger 304 and then to the cold reservoir 202. Advantageously, the fluid circuit 200 comprises a pump 204 and possibly 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 of the figures, the pump 204 is arranged between the outlet of the cold reservoir 202 and the electricity-to-heat transformation module 100 and the pump 205 is arranged between the outlet of the hot reservoir 203 and the interface exchanger 304.

[0047] From a fluid connection point of view, the cold reservoir 202 is fluidically connected, preferably directly, to the pump 204 by the fluid connection 2001 ensuring the circulation of the cold molten salts from the cold reservoir 202 to the pump 204. The pump 204 is fluidically connected, preferably directly, to the electricity-to-heat transformation module 100 by the fluid connection 2002 ensuring the circulation of the cold molten salts from the pump 204 to the electricity-to-heat transformation module 100. The electricity-to-heat transformation module 100 is fluidically connected, preferably directly, to the hot reservoir 203 by the fluid connection 2003 ensuring the circulation of the hot molten salts from the electricity-to-heat transformation module 100 to the hot reservoir 203.The hot reservoir 203 is fluidically connected, preferably directly, to the pump 205 by the fluid connection 2004 ensuring the circulation of the hot molten salts from the hot reservoir 203 to the pump 205. The pump 205 is fluidically connected, preferably directly, to the interface exchanger 304 by the fluid connection 2005 ensuring the circulation of the hot molten salts from the pump 205 to the interface exchanger 304. The interface exchanger 304 is fluidically connected to the cold reservoir 202 by the fluid connection 2006 ensuring the circulation of the cold molten salts from the interface exchanger 304 to the cold reservoir 202, either directly or indirectly through a load exchanger 405 described below according to the embodiment.

[0048] 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 intended to receive water and steam. The steam cycle 301 advantageously comprises 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 by the interface exchanger 304. Conventionally, the steam cycle comprises a condenser 306 arranged downstream of the turbine 302. The condenser 306 is intended to condense the expanded steam at the outlet of the turbine 302.

[0049] The steam cycle 301 is intended for the circulation of steam to supply the turbine 302 in which the steam will be expanded ensuring, thanks to an associated generator 303, the production of electricity from the heat stored in the thermal storage module 200.

[0050] 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 depending on its design. For example, the pressure of the steam cycle is between 100 and 200 bars.

[0051] In the steam cycle 301, the interface exchanger 304 is fluidically connected, preferably directly, to the turbine 302 by a fluid connection A ensuring the circulation of the steam produced in the interface exchanger 304 to the turbine 302 to supply it with steam. The turbine 302 is fluidically connected, preferably directly, to the condenser 306 by a fluid connection B ensuring the circulation of the expanded steam at the outlet of the turbine 302 to the condenser 306 for the purpose of condensing this expanded steam. The condenser 306 is fluidically connected, for example as illustrated in the figures directly, to a pump 305 by a fluid connection C ensuring the circulation of the condensed water at 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 fluid 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 to the interface exchanger 304.

[0052] 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 include any fluid communication. Similarly, in the case where the electricity-to-heat conversion module 100 includes a fluid circuit, then the latter is also fluidically distinct from the fluid circuit 101 and the steam cycle 301.

[0053] Preferably, the fluid circuit 201 is a closed circuit.

[0054] Preferably, the steam cycle 301 is a closed circuit in the sense that it does not include an external water or steam supply for preheating and / or maintaining the temperature of the turbine 302. A water supply may be made only as a supplement to compensate for any possible purges.

[0055] 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 power plant or others.

[0056] The system comprises an additional thermal storage unit 400. The additional thermal storage unit 400 is fluidically connected to the steam cycle 301. The additional thermal storage unit 400 comprises at least one thermal storage device and a set of fluidic connections intended to receive water in the liquid state and / or in the vapor state to ensure the fluidic connection of the thermal storage device to the steam cycle 301.

[0057] The additional thermal storage unit 400 is separate from the thermal storage module 200 of the Carnot battery.

[0058] The additional thermal storage unit 400 makes it possible to use part of the thermal energy stored in the Carnot battery to produce steam and store its thermal energy in the additional thermal storage unit 400 then release it to restore thermal energy to the steam cycle 301 and more particularly to the turbine 302.

[0059] The additional thermal storage unit 400 makes it possible to ensure preheating and / or temperature maintenance of all or part of the steam cycle 301 and more particularly of the turbine 302 by using the thermal energy stored in the Carnot battery. Advantageously, the system according to the invention does not include a steam supply external to the Carnot battery. The additional thermal storage unit 400 makes it possible to restore a low thermal power over a long period, thus ensuring satisfactory preheating and / or temperature maintenance.

[0060] The discharge of the thermal storage module 200 of the Carnot battery is carried out in order to produce electricity when the electricity network is live. This makes it possible to benefit from advantageous electricity buyback tariffs, but implies discontinuous operation. The thermal storage module 200, in particular by molten salt, is not sized for low power, it is therefore shut down during the phases of electricity production shutdown and the steam cycle drops back down in temperature. However, the requirements of the electricity network require that electricity production starts quickly after the signal has been given, which is not possible if the steam cycle is cold. 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.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.

[0061] According to one aspect, the system comprises a buffer tank intended for storing the thermal energy of the steam from the steam cycle 301. The buffer tank is fluidically connected to the steam cycle 301 by a fluidic supply connection of the buffer tank. The fluidic supply connection is advantageously connected downstream of the turbine 302, preferably directly downstream.

[0062] The buffer tank is fluidically connected to the additional thermal storage unit 400 by the return fluid connection 402 ensuring the filling of water into the additional thermal storage unit 400 from the buffer tank 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.

[0063] The buffer tank is fluidically connected to the additional thermal storage unit 400 by the discharge fluid connection 404 ensuring the discharge of water from the additional thermal storage unit 400 to the buffer tank when the thermal storage unit 400 is charged.

[0064] The buffer tank 50 is fluidically connected to the additional thermal storage unit 400 by the load fluid connection 403 ensuring the supply of water from the buffer tank 00 to the load exchanger 405 by a first part 403a then the supply of the thermal storage unit by the steam produced by the load exchanger 405 through a second part 403b of the load fluid connection.

[0065] According to a preferred possibility, the buffer tank is a thermocline thermal storage tank allowing the storage of hot fluid and cold fluid in the same tank, but separated by a temperature gradient (stratification). Advantageously, the buffer tank 50 can store the expanded steam from the turbine 302 for use in charging the thermal storage device of the additional thermal storage unit 400 and it can also store water from the thermal storage device of the additional thermal storage unit 400 when the latter is charging and the steam supplied to the device is transformed into water following the storage of its thermal energy in the thermal storage device. The buffer tank also makes it possible to supply water to the thermal storage device when the latter is in the discharge phase and transmits heat to the steam cycle.

[0066] The buffer tank thus has the advantage of allowing greater independence between the steam cycle and the thermal storage device, in particular for the charging step 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 of the storage device.

[0067] The additional thermal storage unit 400 comprises a fluid supply connection 401 for the turbine 302. The fluid supply connection 401 comes 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, in particular when the thermal storage module of the Carnot battery is charging or stopped. The fluid supply connection 401 ensures the fluid connection of the thermal storage device to the steam cycle 301. The fluid supply connection 401 is either connected directly upstream of the turbine 302 to supply only the turbine 302, as illustrated in the figures 1 to 3, either 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 fluid circuit 201 as illustrated in Figure 4 .

[0068] The additional thermal storage unit 400 comprises 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.

[0069] According to a possibility not illustrated, the return fluid connection 402 is connected to the steam cycle 301 indirectly downstream of the turbine 302. According to this possibility, the system may comprise a buffer tank arranged on the return fluid connection 402 between the steam cycle 301 and the additional thermal storage unit 400.

[0070] According to a preferred possibility illustrated in figures 1 to 4 , the return fluid connection 402 is connected to the steam cycle 301, preferably directly, downstream of the pump 305, and possibly downstream of the condenser 306 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 high exchange coefficient during the evaporation of the water.

[0071] 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.

[0072] The additional thermal storage unit 400 comprises a load fluid connection 403. The load fluid connection 403 provides the fluid connection from the steam cycle 301 to the thermal storage device. The load fluid connection 403 comes from the steam cycle 301 downstream of the turbine 302.

[0073] According to a non-illustrated embodiment, the load fluid connection 403 comes 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 exchanger 304. The load fluid connection 403 comprises a tapping on the steam cycle 301 which is preferably made on the fluid connection D of the steam cycle 301. Preferably, the tapping is arranged downstream of the pump 305 and upstream of the interface exchanger 304. According to this embodiment, the load fluid connection 403 ensures an indirect fluid connection between the steam cycle 301 and the thermal storage device, preferably via the load heat exchanger 405 described below.

[0074] According to a non-illustrated aspect, the load fluid connection 403 may come indirectly from the steam cycle 301 by being connected to the buffer tank, itself fluidically connected to the steam cycle 301 by a fluid connection. The load fluid connection 403 makes it possible to supply the additional thermal storage unit 400 via the load heat exchanger 405 from the buffer tank.

[0075] According to the invention illustrated in figures 1 to 4 , the fluidic charge connection 403 comes from the steam cycle 301 downstream of the turbine 302, preferably by drawing off the turbine 302. The tapping of the fluidic charge connection 403 on the steam cycle 301 is done on the turbine 302. The fluidic charge connection 403 ensures a direct fluidic connection between the steam cycle 301 and the additional thermal storage unit 400.

[0076] The additional thermal storage unit 400 includes a fluid exhaust connection 404.

[0077] The discharge fluid connection 404 provides the fluid connection of the additional thermal storage unit 400 to the steam cycle 301. This discharge fluid connection 404 allows the discharge of water from the thermal storage device to the steam cycle 301 when the thermal storage device receives steam from the steam cycle 301 via the load fluid connection 403. As a preferred example, the discharge fluid connection 404 is fluidly connected to the steam cycle 301 downstream of the turbine 302 so as not to impact 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.

[0078] According to another aspect not illustrated, the discharge fluid connection 404 provides the fluid connection of the additional thermal storage unit 400 to the buffer tank. This discharge fluid connection 404 allows the discharge of water from the thermal storage device to the buffer tank when the thermal storage device receives steam from the steam cycle 301 via the load fluid connection 403.

[0079] 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 step of the thermal storage device of the additional thermal storage unit 400.

[0080] Advantageously, the supply fluid connection 402, the return fluid connection 401, the load fluid connection 403 and the discharge fluid connection 404 are separate fluid connections. The system comprises at least four fluid connections, and possibly at least five fluid connections, ensuring fluid circulation between the thermal storage device of the additional thermal storage unit 400 and the steam cycle 301 of the heat-to-electricity transformation module and possibly the buffer tank.

[0081] The at least one thermal storage device of the additional thermal storage unit 400 may be latent and / or sensitive storage. The at least one thermal storage device is chosen from a thermal storage system using a phase change material (PCM) 4001, a steam accumulator 4002, a sensitive air-solid storage system 4003 or even a thermocline system.

[0082] A thermal storage system by MCP 4001 that can be used as a thermal storage device of the additional thermal storage unit 400 is illustrated in figures 1 to 4 .

[0083] Preferably, the thermal storage system (TSS) by MCP is a shell-and-tube exchanger in which a tank, the shell, receives a phase change material (MCP). The tank is traversed by a bundle of tubes through which water circulates in the liquid state and / or in the vapor state in fluidic connection with the vapor cycle 301 and more precisely by the fluidic connections 401, 402, 403, 404 in fluidic connection with the bundle of tubes.

[0084] The phase change material is chosen based on the desired working temperature. For example, sodium nitrate (NaNos) can be used for a temperature around 300°C.

[0085] The use of a thermal storage system (TSS) by PCM comprising a shell and tube exchanger has the advantage of having the water in the liquid state and / or in the vapor state separated from the PCM by the tube bundle. The pressure elements are thus only composed of the tube bundle and two distributors at each end of the tubes. The shell which contains the PCM operates under a pressure close to atmospheric pressure. Exploiting the latent heat of the change of state of the PCM, preferably a solid / liquid PCM, allows the storage and release of steam with a low temperature variation. Thus during release, the pressure and temperature of the steam produced remain very stable.

[0086] According to another alternative or cumulative possibility, the thermal storage device is a steam accumulator 4002 as illustrated in figures 2 And 3 .

[0087] A 4002 steam accumulator has a very good responsiveness allowing the steam to be discharged quickly after the instruction is transmitted. With a 2002 steam accumulator, steam is delivered in a few seconds, or even instantaneously, to the fluid supply connection 401.

[0088] According to a non-illustrated embodiment where the accumulator 4002 is the only thermal storage device, the steam accumulator 4002 is in fluid connection with the steam cycle 301, more precisely by the fluid connections 401, 402, 403, 404.

[0089] According to another alternative or cumulative possibility to the two previous 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 Figure 3. This type of storage by sensible heat in a solid material comprises a solid material enclosure and a steam / air heat exchanger. The air circulates in the heat exchanger and recovers the thermal energy therefrom. 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, involving no risks (chemical, fire, etc.) and capable of reaching very high temperatures, in particular up to 1000°C. According to an embodiment not illustrated where the accumulator 4002 is the only thermal storage device, the sensible heat storage system 4003 is in fluid connection with the steam cycle 301, more precisely by the fluid connections 401, 402, 403, 404 and a water-steam / air heat exchanger 4003a.

[0090] According to another example not shown, 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.

[0091] The additional thermal storage unit 400 comprises one or more thermal storage devices. Several combinations of the thermal storage devices described above may be envisaged. Some examples of combinations of thermal storage devices are illustrated in figures 2 And 3 . A combination of an SST by MCP 4001 and a steam accumulator 4002, at the Figure 2 , a combination of an SST by MCP 4001, a steam accumulator 4002 and a solid sensible heat storage system 4003 at the Figure 3 .

[0092] Advantageously, the SST by MCP 4001 and the steam accumulator 4002 are arranged in parallel for the load 403 and supply 401 fluid connections and in series for the return 402 and exhaust 404 fluid connections as illustrated in figures 2 And 3 .

[0093] In Figure 3 , advantageously, the SST by MCP 4001 and the steam accumulator 4002 are arranged in parallel for the load 403 and supply 401 fluid connections and in series for the return 402 and discharge 404 fluid connections 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 bypass of this solid sensible heat storage system 4003 can be provided. In this case, we fall back on an operation identical to that of the Figure 3 .

[0094] According to a first embodiment, the at least one thermal storage device is fluidically connected to the steam cycle indirectly to ensure its charging. More specifically, the charging fluid connection 403 ensures the supply of steam to the storage device of the additional thermal storage unit 400 through the charging heat exchanger 405. This embodiment can be combined with the presence of a buffer tank or be provided without it with a charging fluid connection 403 connected to the steam cycle 301.

[0095] Following this first embodiment illustrated in the Figure 3, the thermal storage device of the additional thermal storage unit 400 is connected to the steam cycle 301 by the load fluid connection 403 passing through a load heat exchanger 405. The load heat exchanger 405 is arranged on the molten salt fluid circuit 201 and on the load 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 precisely to the load fluid connection 403. The load heat exchanger 405 has a lower power than the interface heat exchanger 304. According to one aspect of this first embodiment, the load fluid connection 403 can come from the buffer tank, itself connected for its supply to the steam cycle 301 downstream of the turbine 302 by a fluid connection.In this embodiment, the load fluid connection 403 comprises a first portion 403a and a second portion 403b. The first portion of the load connection 403a extends between the steam cycle 301 and the load exchanger 405. This first portion of the load fluid connection 403a ensures the circulation of water from the steam cycle 301 to the load heat exchanger 405. The load heat exchanger 405 ensures the transformation of the water brought by the first portion of the load fluid connection 403a into steam. The second portion of the load fluid connection 403b extends between the load heat exchanger 405 and the thermal storage device. This second portion of the load fluid connection 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 load fluid connection part 403b. The connection of the steam cycle and the thermal storage device is indirect with respect to the load.

[0096] According to a second embodiment illustrated in figures 1 to 3 , the at least one thermal storage device is fluidically connected to the steam cycle directly to ensure its charging. More specifically, the charging fluid connection 403 ensures the supply of steam to the storage device of the additional thermal storage unit 400 without passing through the charging heat exchanger 405. The connection of the steam cycle and the thermal storage device is direct with regard to the charging.

[0097] According to this second embodiment, the thermal storage device of the additional thermal storage unit 400 is connected to the steam cycle 301 by the load fluid connection 403 directly. According to this second embodiment, the load fluid connection 403 comes from the steam cycle 301 downstream of the turbine 302, preferably by drawing off the turbine 302. The tapping of the load fluid connection 403 on the steam cycle 301 is done on the turbine 302. Steam comes directly from the steam cycle 301 and more precisely from the turbine 302 by the load fluid connection 403 which ensures its circulation directly to the thermal storage device.

[0098] Preferably, the first embodiment and the second embodiment are alternatives.

[0099] According to a third embodiment that can be combined with the first embodiment or the second embodiment, the fluid supply connection 401 comes from the thermal storage device and 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 the steam cycle 301 with steam. The fluid supply connection 401 extends between the storage device and the tapping 4011 on the steam cycle arranged according to a possibility on the fluid connection A.According to a fourth embodiment alternative to the third embodiment and which can also be combined with the first embodiment or the second embodiment, the fluid supply connection 401 comes 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 fluid supply connection 401 extends between the storage device and the tapping 4011 on the steam cycle arranged on the fluid connection D as illustrated in . Figure 4. The tapping 4011 of the supply fluid connection is arranged downstream of a possible tapping of the load fluid connection 403 on the fluid connection D of the steam cycle. In this fourth embodiment, the supply fluid connection 401 makes it possible to circulate steam in the interface heat exchanger 304 when the molten salt fluid circuit is stopped. This arrangement thus makes it possible to limit the risks of the molten salts crystallizing in the interface heat exchanger and damaging it while ensuring a supply of steam to the turbine 302.

[0100] There Figure 2is detailed below with regard to the arrangement of the thermal storage devices. The load 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 comprises a bypass fluid connection 403d for supplying a second storage device in parallel as illustrated in the example of figures 2 And 3The fluid connection 403 supplies the MCP thermal storage system 4001 and the bypass fluid connection 403d ensures the bypass of the fluid connection 403 to the second storage device, i.e. the steam accumulator 4002. The supply fluid connection 401 also comprises a bypass fluid connection 401d ensuring the bypass from the second storage device, the steam accumulator 4002, to the fluid connection 401. Advantageously, the MCP thermal storage system 4001 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 thermal storage system by MCP 4001 to the steam accumulator 4002.The additional exhaust fluid connection 404a provides the fluid connection from the steam accumulator 4002 to the MCP thermal storage system 4001. The MCP thermal storage system 4001 is not connected directly to the steam cycle 301 with respect to the return fluid connection and the exhaust fluid connection, but indirectly through the steam accumulator 4002. The steam accumulator 4002 is fluidly connected to the steam cycle by the return fluid connection 402 and by the exhaust fluid connection 404. The steam accumulator 4002 is fluidly connected to the steam cycle by the bypass supply fluid connection 401d and the bypass charge fluid connection 403d.

[0101] There Figure 3is detailed below with regard to the arrangement of the thermal storage devices. The load fluid connection 403 comprises the first part of the fluid connection 403a connecting the steam cycle 301 to the load heat exchanger 405, the second part of the fluid connection 403b connecting the load heat exchanger 405 to the thermal storage device and more particularly to the MCP thermal storage system 4001. The system comprises, arranged on this fluid connection 403b, a heat exchanger 4003a ensuring the heat exchange between the steam circulating in the fluid connection 403b and air intended to circulate in the sensitive storage device 4003. The load fluid connection 403b comprises a bypass fluid connection 403d ensuring the fluid connection between the load fluid connection 403 and the steam accumulator 4002.The supply 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 supply fluid connection 401 to ensure the recovery of the thermal energy stored in the sensitive storage device 4003. A bypass supply fluid connection 401d provides the connection between the steam accumulator 4002 and the supply fluid connection 401. The return 402 and exhaust 404 fluid connections are similar to what is described with regard to the . Figure 2 .

[0102] According to another aspect, the invention relates to a method for heating and / or maintaining heat in 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 method comprises a step of charging the thermal storage device of the additional thermal storage unit 400. This charging step makes it possible to store thermal energy in the thermal storage device of the additional thermal storage unit 400 for use during preheating and temperature maintenance.

[0104] The charging step comprises circulating steam from the steam cycle 301 to the thermal storage device. The charging step comprises circulating steam in a closed circuit from the steam cycle 301 to the thermal storage device.

[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] According to a non-illustrated embodiment, the expanded water after the outlet of the turbine 302 and advantageously after the condenser 306 and even more advantageously after the pump 305 is taken from the steam cycle by the load fluid connection 403 and more precisely by the first part of the load fluid connection 403a. The expanded water is vaporized in the load exchanger 405. The steam produced in the load exchanger 405 is conducted to the thermal storage device by the second part of the load fluid connection 403b. This embodiment makes it possible to adapt the system according to the invention to different types of steam cycle 301 even if the turbine 302 does not have a draw-off.

[0107] During the charging step, steam, including the thermal energy of the steam, is supplied from the steam cycle 301 to the thermal storage device. During this step, water is discharged from the thermal storage device through the fluid connection 404. The discharged water is returned to the steam cycle 301.

[0108] According to a non-illustrated aspect, the steam leaving the turbine 302 is taken, for example at the fluid connection B, by a fluid connection to be stored in a buffer tank. When it is necessary to charge the additional storage unit 400, the steam present in the buffer tank 500 is transmitted by the load fluid connection 403, more precisely the first part 403a, to the load heat exchanger 405. The heat exchanger 405 will make it possible to produce the steam which is transmitted to the additional thermal storage unit 400 by the fluid connection 403, more precisely the second part of the fluid connection 403b.

[0109] According to the invention illustrated in figures 1 to 4, a portion of the steam produced in the steam cycle 301 by the interface heat exchanger 304 is taken for the benefit of the thermal storage device of the additional thermal storage unit 400. Preferably, the portion of steam taken is less than 100% and preferably less than 50%, for example of the order of 5 to 30%. According to the invention, the steam is taken from the steam cycle preferably directly by a withdrawal on the turbine 302. This embodiment is possible when the turbine is configured to allow such withdrawal. This embodiment makes it possible to avoid the use of an additional load heat exchanger.

[0110] The method according to the invention comprises a step of preheating and / or maintaining the temperature of all or part of the steam cycle 301 and more precisely of the turbine 302. Advantageously, the preheating and / or maintaining the temperature step takes place when the thermal storage module 200 of the Carnot battery is not releasing thermal energy to the electricity production module. It is therefore when there is no release of thermal energy from the thermal storage module 200 of the Carnot battery that the preheating and / or maintaining the temperature step takes place. This preheating and / or maintaining the temperature step makes it possible to release the thermal energy in the form of steam from the thermal storage device of the additional thermal storage unit 400 to the steam cycle 301 and in particular the turbine 302 when the latter is not used for the production of electricity.The circulation of steam from the storage device to the steam cycle 301 is done via the supply fluid connection 401.

[0111] During the preheating and / or temperature maintenance step, expanded water is brought from the steam cycle 301 to the thermal storage device via the fluid connection 402.

[0112] According to the third embodiment, the preheating and / or temperature maintenance step makes it possible to supply steam to the turbine 301, the fluid supply connection 401 opening upstream of the turbine 302 and preferably downstream of the interface heat exchanger 304.

[0113] According to a fourth embodiment, the preheating and / or temperature maintenance step makes it possible to supply steam to the turbine 301 and the interface heat exchanger 304, the fluid supply connection 401 opening upstream of the turbine 302 and upstream of the interface heat exchanger 304.

[0114] According to the invention, the method comprises a step of transforming electricity into heat by the electricity into heat transformation module 100. This step of transforming electricity into heat is carried out when the electricity produced in particular by an intermittent source for example which is not used immediately or which is inexpensive, it is therefore transformed into the form of heat.

[0115] The method comprises a step of storing the heat produced by the electricity-to-heat transformation module 100. The heat storage step is carried out by the thermal storage module 200 in thermal connection with the electricity-to-heat transformation module 100. The heat produced by the electricity-to-heat transformation module 100 is transmitted to the thermal storage module 200. The heat is then stored as described above with reference to the thermal storage module 200.

[0116] The method comprises a step of transforming the stored heat into electricity. This step of transforming the stored heat into electricity takes place when the need for electricity arises. This step of transforming the stored heat into electricity comprises the release of the heat stored in the thermal storage module 200 to the module for transforming the stored heat into electricity 300 and more particularly its steam cycle 301. LIST OF REFERENCES

[0117] 100. Electricity-to-heat conversion module 200. Thermal storage module for the heat produced 201. Molten salt fluid circuit 202. Cold reservoir 203. Hot reservoir 204. First Pump 205. Second Pump 2001. Fluid connection between the outlet of the cold salt reservoir 202 and the inlet of the pump 204. 2002. Fluid connection between the outlet of the pump 204 and the electricity-to-heat conversion module 100 2003. Fluid connection between the electricity-to-heat conversion module 100 and the inlet of the hot salt reservoir 203. 2004. Fluid connection between the outlet of the hot salt reservoir 203 and the inlet of the pump 205 2005. Fluid connection between the outlet of the pump 205 and the inlet of the interface heat exchanger 304 2006. Fluid connection between the outlet of the interface heat exchanger 304 and the inlet of the cold salt tank 202. 2006a.Fluid connection between the outlet of the interface heat exchanger 304 and the inlet of the load heat exchanger 405 2006b. Fluid connection between the outlet of the load 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 exchanger thermal storage module and steam cycle 305. Pump 306. Condenser 400. Additional thermal storage unit 4001. SST by MCP 4002. Steam accumulator 4003. Solid Sensible Storage System 4003a. Air / steam exchanger 401. Turbine feed fluid connection 401d. Turbine feed fluid connection branch 4011. Feed fluid connection branch 402. Return fluid connection 402a. Return fluid connection between steam accumulator and SST via MCP 403. Load fluid connection 403a.First part of the load fluid connection between the steam cycle and the interface exchanger 403b. Second part of the load fluid connection between the interface exchanger and a thermal storage device 403d. Branch of the load fluid connection 404. Discharge fluid connection 404a. Discharge fluid connection between steam accumulator and SST by MCP 405. Load heat exchanger 406. Pump 407. Pump A. Fluid connection between interface heat exchanger outlet 304 and turbine inlet 302 B. Fluid connection between turbine outlet 302 and condenser inlet 306 C. Fluid connection between condenser outlet 300 and pump inlet 305 D. Fluid connection between pump outlet 305 and interface heat exchanger inlet 304.

Claims

1. System comprising a Carnot battery comprising a module for transforming electricity into heat (100), a module for thermal storage of the heat produced (200) by the module for transforming electricity into heat (100), and a module for transforming the heat (300), destored from the storage module, into electricity, the module for transforming the heat destored (300) from the storage module into electricity comprising a steam cycle (301) and a turbine (302) arranged on the steam cycle (301) to expand the steam for the production of electricity, Characterized in thatthe system comprises an additional thermal storage unit (400) fluidically 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) comprising • at least one thermal storage device, • a pair of preheating fluid connections comprising ∘ a fluid connection (401) for supplying steam to the turbine arranged between the thermal storage device and the steam cycle (301) upstream of the turbine (302) making it possible to ensure the fluidic connection of the thermal storage device to the steam cycle (301) so as to ensure preheating and / or maintaining the temperature of all or part of the steam cycle (301) and preferably at least the turbine (302),and ∘ a return fluid connection (402) arranged between the steam cycle (301) downstream of the turbine (302) and the thermal storage device making it possible to ensure the fluid connection of the steam cycle (301) to the thermal storage device so as to ensure the return of the expanded steam and / or water at the outlet of the turbine (302) to the thermal storage device, • a pair of charge fluid connections comprising ∘ a charge fluid connection (403) arranged between the steam cycle (301), downstream of the turbine (302), and the thermal storage device making it possible to ensure the fluid connection of the steam cycle (301) to the thermal storage device so as to charge the thermal storage device with thermal energy by the steam from the steam cycle (301), and ∘ an evacuation fluid connection (404) arranged between the storage device and the steam cycle (301) downstream of the turbine (302),so as to ensure the circulation of water from the storage device to the steam cycle (301)., 2. System according to claim 1 comprising a charge heat exchanger (405) arranged on the thermal storage module (200) of the Carnot battery and on the charge fluid line (403).

3. System according to claim 1 in which the fluidic charge line (403) coming from the steam cycle (301) fluidically connects the steam cycle (301) directly to the thermal storage device, by withdrawal at the level of the turbine (302).

4. System according to any one of the preceding claims in which the Carnot battery comprises an interface heat exchanger (304) arranged between the module for storing the heat produced (200) and the steam cycle (301) so as to ensure the 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) downstream of the interface heat exchanger (304).

5. System according to any one of claims 1 to 3 wherein the Carnot battery comprises an interface heat exchanger (304) arranged between the module for storing the heat produced (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).

6. System according to any one of the preceding claims wherein the thermal storage device comprises a thermal storage system (TSS) by phase change material (PCM).

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

8. A system according to any preceding claim wherein the thermal storage device comprises a sensitive storage.

9. 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).

10. System according to any one of the preceding claims in which the steam cycle (301) and the turbine (302) are part of a coal-fired power station.

11. 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 fluid circuit (201) intended to receive at least one molten salt and ensuring the fluid connection between a cold reservoir (202) intended to store the cold molten salt, a hot reservoir (203) intended to store the hot molten salt, a pump (204), the module for transforming electricity into heat (100), and an interface heat exchanger (304) through which the steam cycle (301) circulates.

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

13. Method for preheating and / or maintaining the temperature of a turbine (302) of a system according to any one of claims 1 to 11 comprising a step of charging the thermal storage device of the additional thermal storage unit comprising the circulation of steam to the thermal storage device from the steam cycle (301), and alternatively a step of preheating and / or maintaining the temperature of the turbine (302) comprising the circulation of steam from the thermal storage device to the steam cycle (301).

14. Method according to the preceding claim comprising a step of producing electricity by the turbine (302), the step of charging the thermal storage device being carried out during this step of producing electricity.

15. Method according to the preceding claim in which the step of preheating and / or maintaining the temperature of the turbine (302) is carried out alternately with the step of producing electricity.

Images