Method for thermal energy storage and thermal energy store

Abstract

The present invention relates to a method for thermal energy storage, involving at least three containers which are each filled with a solid bulk material, wherein a heat transfer medium for charging or discharging thermal energy is introduced into a first container, wherein, prior to charging, a second container is at least partially pre-filled with cold heat transfer medium from the first container, or, prior to discharging, is at least partially pre-filled with hot heat transfer medium from the first container, wherein, during charging, the first container is supplied with hot heat transfer medium from a third container or, during discharging, is supplied with cold heat transfer medium from a third container, wherein a heat transfer zone passes through the first container during charging or discharging and, after complete charging or discharging of the first container, is propagated into the second container, thereby enabling a continuous charging mass flow or discharging mass flow. The invention also relates to a corresponding thermal energy store.

Description

[0001] Methods for thermal energy storage and thermal energy storage rather

[0002] The present invention relates to a method for thermal energy storage with at least three containers, each filled with a solid. Furthermore, the invention relates to a thermal energy storage device, in particular for carrying out a method according to the invention.

[0003] TECHNICAL BACKGROUND

[0004] Energy storage is advantageous for compensating for fluctuating electricity generation and consumption. Especially when using different renewable energy sources, energy storage and reserve capacity represent a crucial component of the energy transition in the context of climate change.

[0005] Energy can be stored in energy storage devices, of which mechanical, chemical, or electrical storage devices are known, for example. Thermal energy storage devices are also known, which offer advantages over chemical or electrical storage devices, particularly with regard to the cost per unit of energy and the amount of energy stored.

[0006] In the case of thermal energy storage systems, solid-state and liquid storage systems are known from the prior art. For a temperature range of 90°C to 400°C, temperature-stratified energy storage systems with a thermal oil-based heat transfer medium are also advantageous. In contrast to water-based energy storage systems, the internal pressure caused by saturated steam does not need to be taken into account. Temperature stratification, in particular, prevents mixing losses or "exergy losses." Furthermore, a comparatively long extraction period at a high temperature level can be ensured if the energy storage system is appropriately charged or discharged.

[0007] To supply energy to the energy storage device, it is charged. It is known from the prior art to introduce a thermal oil into the energy storage device from the top, allowing a flow of hot thermal oil from top to bottom. To extract energy from the energy storage device, it is discharged. For example, cool thermal oil can be introduced into the container from bottom to top.

[0008] Since thermal oil is expensive, a cost-effective solid fill, such as gravel, can be introduced into the storage tank to reduce costs. This allows a portion of the expensive thermal oil to be replaced. In particular, storage tanks are known from the prior art in which the solid fill occupies 60% to 70% of the volume and can provide approximately 60% to 80% of the heat capacity.

[0009] A disadvantage is that the cost of thermal oil is many times higher than the cost of solid fill, for example, 10 to 20 times higher, especially when considering the same heat capacity. Therefore, it is desirable to further reduce the thermal energy requirement. In particular, temperature stratification within the energy storage system should still be possible.

[0010] SUMMARY OF THE INVENTION

[0011] Against this background, the present invention aims to provide a method for thermal energy storage and a thermal energy storage device, wherein the amount of heat transfer medium can be further reduced.

[0012] According to the invention, this problem is solved by a method with the features of claim 1 and / or by a thermal energy storage device with the features of claim 13.

[0013] Accordingly, the following is planned:

[0014] - A method for thermal energy storage with at least three containers, each filled with a solid, wherein a heat transfer medium for storing or withdrawing thermal energy is introduced into a first container, wherein a second container is at least partially pre-filled with cold heat transfer medium from the first container before storage or at least partially pre-filled with hot heat transfer medium from the first container before withdrawal, wherein hot heat transfer medium is supplied to the first container during storage or cold heat transfer medium during withdrawal from a third container, wherein a heat transfer zone is passed through the first container during storage or withdrawal and is transferred from the first container to the second container after complete storage or withdrawal.enabling a continuous loading mass flow or unloading mass flow.

[0015] - A thermal energy storage device, particularly for carrying out a method according to the invention, comprising at least three containers, each filled with a solid material, wherein the containers are connected to one another in such a way that a heat transfer medium for storing and / or discharging thermal energy can be successively introduced into and / or discharged from the containers, such that a heat transfer zone can be sequentially routed through the containers and a continuous loading or discharging mass flow can be established. The underlying principle of the present invention is to divide a thermal energy storage system into several containers, wherein a heat transfer zone can be routed through the containers, particularly sequentially.In this way, a large storage volume can be achieved as a single container, while at the same time the amount of heat transfer medium can be reduced by the partial volumes of the individual containers.

[0016] The underlying idea of ​​the present invention is to use a heat transfer medium primarily for heat transport during storage and discharge, wherein three containers are connected in a functional arrangement. According to the invention, at least three, in particular relatively small, containers are used, which can be charged and discharged sequentially. A small quantity of heat transfer medium is sufficient for energy storage, in particular sufficient to fill only a subset of the containers, for example, one or two containers. This allows the storage volume for the charging and discharging process of a container to be kept small, thereby reducing the volume fraction of the required heat transfer medium, such as, in particular, thermal oil or a salt.

[0017] The entire thermal energy storage system is divided into at least three containers, which can be filled sequentially with the heat transfer medium. This results in a small volume for each container compared to the total energy storage capacity. Consequently, less heat transfer medium is required to charge or discharge a smaller container, a so-called sub-container, of the overall thermal energy storage system. According to the invention, this significantly reduces costs, particularly the cost of the heat transfer medium, due to the small volume fraction of the container sub-containers. A container can be understood as a separate volume fraction in which a solid material is arranged.The at least three containers can be provided within a single container, whereby the containers can share common partitions, allowing for the separation of different volumes within a larger container into sub-containers. Furthermore, the containers can be arranged side by side, particularly separately from one another, to form an energy storage system.

[0018] A solid fill can fill a large portion of the volume of any container. In particular, the respective container is completely filled with the solid fill. Gravel, for example, can be used as the solid fill.

[0019] Furthermore, different storage materials can be used, which, for example, are porous and / or contain cavities. In particular, the solid packing is formed from bodies arranged at intervals, so that the heat transfer medium can reach the surface of the individual elements of the solid packing.

[0020] Suitable heat transfer media include thermal oil or a thermal oil-based heat transfer medium. Other fluid media capable of storing energy are also conceivable. For example, all liquid heat transfer media, such as salts, can be used.

[0021] A continuous loading or unloading mass flow means, in particular, that a heat transfer zone can be passed through the containers sequentially. The heat transfer zone can, for example, be guided through the container from bottom to top or from top to bottom. Once the heat transfer zone has passed through the container, it can be transferred to the next container by initiating a loading or unloading process there. Advantageously, this allows for continuous operation through several containers, eliminating the need for an expansion tank.

[0022] The flow direction of the heat transfer medium is, in particular, opposite to the flow direction during loading during unloading. However, both processes can be carried out in the same system with the same components.

[0023] The second container is at least partially pre-filled with medium, whereby in one possible embodiment the second container can also be completely or almost completely filled when it is pre-filled with medium.

[0024] Advantageous designs and further developments result from the further sub-claims as well as from the description with reference to the figures in the drawing.

[0025] According to an advantageous embodiment, only the container in which the heat transfer zone is located can be completely filled with heat transfer medium. This can be achieved, for example, by allowing each container to be controlled separately and therefore filled independently from another container. Once one container is filled, the next container to be loaded or unloaded can then be filled with the medium. For continuous operation, at least three containers are necessary.

[0026] In a preferred embodiment, the hot heat transfer medium can be supplied uniformly and with minimal turbulence during storage. The supply is particularly effective from the top of the container. During storage, pre-filling with cold heat transfer medium from below can be continued, particularly until a suitable and turbulence-free inflow of hot heat transfer medium from above is possible. In particular, the container can initially be completely pre-filled with cold heat transfer medium. During storage, especially when hot medium is supplied from the top, the interior of the container initially has a higher temperature in the upper region than in the lower region, whereby the heat transfer zone can be directed downwards through the container and subsequently into the next container.During emptying, the heat transfer zone moves through the container, especially from bottom to top, with a pre-filling with hot medium followed by the addition of cold medium, especially from below.

[0027] According to an advantageous embodiment, during the charging process, cold heat transfer medium can be fed from the first container to a heat exchanger, and hot heat transfer medium can be fed from the heat exchanger to the first container, while the heat transfer zone moves through the first container. In other words, the heat transfer medium can be fed from a cold side of the container, particularly via at least one line, especially to a pump, and to the heat exchanger. This can be referred to as a heat transfer circuit. The heat exchanger can, in this case, be called a charging heat exchanger, wherein hot heat transfer medium can be fed from the heat exchanger to a hot side of the container, particularly via at least one line.The heat transfer zone can move within the container from the hot side towards the cold side, especially until the entire container is loaded.

[0028] According to an advantageous embodiment, during discharge, hot heat transfer medium from the first vessel can be fed to a heat exchanger, and cold heat transfer medium from the heat exchanger can be fed back to the first vessel, while the heat transfer zone moves through the first vessel. In other words, the heat transfer medium can be fed from a hot side of the vessel, particularly via at least one line, to the heat exchanger, and especially to a pump. This can be referred to as a heat transfer circuit. The heat exchanger can, in this case, be called a discharge heat exchanger, wherein cold heat transfer medium can be fed from the heat exchanger to a cold side of the vessel, particularly via at least one line.The heat transfer zone can move within the container from the cold side towards the hot side, especially until the entire container is unloaded.

[0029] In both cases, the same components and thus the same energy storage system can be used, whereby the flow direction during discharge can be aligned opposite to the flow direction during charging.

[0030] According to an advantageous embodiment, the at least three containers can be connected to the heat exchanger sequentially during storage or discharge. For example, each container can be controlled via lines that have at least one valve. In particular, each container is connected at its bottom and top to at least one line, which can be configured as an inlet and an outlet. The lines can be configured as at least one piping system that can have valves which allow or prevent the flow of fluid to or from the respective container. Furthermore, at least one pump can be provided to enable the flow of the heat transfer medium between the containers and the heat exchanger.

[0031] According to an advantageous embodiment, the at least three containers can be connected to the heat exchanger via valves, with at least one valve being arranged on opposite sides of each container. By opening two valves, the heat transfer medium can be directed from the container to the heat exchanger and back to the container. This allows the containers to be loaded and unloaded sequentially. According to an advantageous embodiment, pressure equalization can occur between the containers during loading and / or unloading. This pressure equalization is achieved, in particular, by connecting the containers to one another.For example, pressure equalization can be achieved by means of a heat transfer medium that can be conveyed directly from one container to at least one next container during storage or discharge, without passing through the heat exchanger, in particular to the second container.

[0032] According to an advantageous embodiment, the containers can be interconnected via at least one transfer system, whereby pressure equalization is achieved in particular by the transfer system. Preferably, pressure equalization between three containers is possible, wherein heat transfer medium is simultaneously taken from a further container, the third container, and supplied to a further container, the second container, in the container to be unloaded or loaded, in particular called the first container. Thus, at least two circuits can be formed, wherein a first circuit can be designed for transporting hot heat transfer medium, and a second circuit for transporting cold heat transfer medium.

[0033] According to an advantageous embodiment, the containers can therefore be interconnected via two transfer systems, a first transfer system being filled with cold heat transfer medium and a second transfer system being filled with hot heat transfer medium. Each transfer system can form a circuit and, in particular, include a pump. During storage, the flow direction can be opposite to the flow direction during discharge.

[0034] According to an advantageous embodiment, during the filling of the first container, hot heat transfer medium can be introduced from the bottom of the third container into the top of the first container, and simultaneously, cold heat transfer medium can be introduced from the bottom of the first container into the second container, with the heat transfer zone flowing from top to bottom through the first container. Advantageously, the three containers are connected in such a way that the volume of heat storage medium can be equalized between the containers. This connection can be established by at least one, and in particular two, transfer pump systems.

[0035] In other words, during a loading process, the next container to be loaded can be pre-filled with cold medium, whereby the medium can be supplied from another container.

[0036] According to an advantageous embodiment, during the emptying of the first container, cold heat transfer medium can be introduced from the bottom of the second container into the first container, and simultaneously hot heat transfer medium can be introduced from the top of the first container into the third container, with the heat transfer zone passing through the first container from bottom to top. In other words, during an emptying process, the next container to be emptied can be pre-filled with hot medium, which can be supplied from another container.

[0037] According to an advantageous embodiment, the second container can be loaded or unloaded analogously to the first container, whereby heat transfer medium is supplied to or removed from the first and a fourth container, and subsequently, the fourth container can be loaded. The process can thus be carried out continuously for a large number of containers, whereby any number of containers can be loaded or unloaded.

[0038] Advantageously, a method according to the invention allows the required amount of heat transfer medium to be reduced to the volume of two containers. The remaining containers are preferably filled only with the solid material in both the loaded and unloaded states. This allows for a significantly lower requirement of heat transfer medium, depending on the number of containers.

[0039] According to an advantageous embodiment, a volume of heat transfer medium equivalent to two containers can be stored. This is particularly possible with a driving mode as described above, where only one container is completely filled with heat transfer medium. It is also conceivable to store a quantity of three or four containers of heat transfer medium, whereby, for example, two containers can be loaded or unloaded simultaneously.

[0040] According to an advantageous embodiment, three to fifteen containers, in particular five to ten containers, are included, with the heat transfer zone being routed through all containers. In particular, in an example where ten containers are used, only the amount of heat transfer medium required for two containers is needed, resulting in a saving of approximately 80% compared to a prior art thermal energy storage system.

[0041] The number of containers can be adjusted as needed, depending on the desired or possible capacity, and is not limited to the numbers specified here. For example, up to one hundred or several hundred containers can be used; there is no limit to the number.

[0042] For further ventilation and / or volume equalization, a protective gas can be used. Nitrogen, in particular, can be used to prevent oxidative effects on the heat transfer medium or other structural components. Alternatively or additionally, a gas phase can be formed by a portion of the evaporated heat transfer medium. This gas phase can be discharged from the respective container. In one embodiment, volume equalization can occur between the containers, for example, by connecting them via a compensating line. In another embodiment, an equalization tank or a storage tank can be provided to temporarily store the protective gas.For example, an overpressure or underpressure of a protective gas, which exists depending on the state of the energy storage device, can be compensated for. Advantageously, a closed system can be in a charged or discharged state, whereby the protective gas is either under overpressure or under pressure.

[0043] The containers preferably have thermal insulation to limit heat loss.

[0044] The invention further relates to a thermal energy storage device. The thermal energy storage device can be used, in particular, to implement the method according to the invention. Accordingly, the same features and advantages apply to the thermal energy storage device as described with respect to the method.

[0045] According to an advantageous embodiment of the energy storage system, the at least three containers can each be connected to a heat exchanger via at least two valves, so that cold heat transfer medium can be drawn from one side of each container and hot heat transfer medium can be introduced into the opposite side, or vice versa. This allows, in particular, continuous operation with a continuous charging flow, and eliminates the need for a buffer tank for the heat transfer medium. The above embodiments and further developments can be combined with one another as appropriate. Further possible embodiments, further developments, and implementations of the invention also include combinations of features of the invention described above or below with regard to the exemplary embodiments, even if not explicitly mentioned.In particular, the person skilled in the art will also add individual aspects as improvements or additions to the respective basic form of the present invention.

[0046] CONTENT OF THE DRAWING

[0047] The present invention is explained in more detail below with reference to the exemplary embodiments shown in the schematic figures of the drawings. These show:

[0048] Fig. 1 shows a thermal energy storage device in one possible design form during a charging process;

[0049] Fig. 2 shows a thermal energy storage device in one possible design form during a discharge process;

[0050] Fig. 3 shows a temperature profile in a container as a binary storage medium.

[0051] The accompanying drawings are intended to provide a further understanding of the embodiments of the invention. They illustrate embodiments and, in conjunction with the description, serve to explain the principles and concepts of the invention. Other embodiments and many of the advantages mentioned become apparent with reference to the drawings.

[0052] The elements of the drawings are not necessarily shown to scale with each other.

[0053] In the figures of the drawing, identical, functionally equivalent, and similarly acting elements, features, and components are—unless otherwise stated—each designated with the same reference symbols. DESCRIPTION OF EXAMPLES OF EXECUTION

[0054] Figures 1 and 2 show a thermal energy storage device 10 in one possible embodiment. In this embodiment, the thermal energy storage device 10 has five containers 1a, 1b, 1c, 1d, 1le, although a different number is possible. Each of the containers 1a, 1b, 1c, 1d, 1le is filled with a solid bed 2. The containers 1 are connected via several lines 8 such that a heat transfer medium for storing and / or releasing thermal energy can be successively introduced into or removed from the containers 1a, 1b, 1c, 1d, 1le in such a way that a heat transfer zone 4 is sequentially guided through the containers 1a, 1b, 1c, 1d, 1le and thus through the solid bed 2, thereby creating a continuous charging mass flow.

[0055] The designation of the containers from a to d is arbitrary, and the arrangement can be in any order.

[0056] In the illustrated embodiment of a loading process in Fig. 1, the heat transfer zone 4 is located in the first container 1a and can be transferred to the second container 1b in a subsequent loading step. Advantageously, only container 1a, in which the heat transfer zone 4 is located, is completely filled with heat transfer medium 3.

[0057] In this embodiment, the containers 1a, 1b, 1c, 1d, and 1le are each connected to the heat transfer circuit 13 via two lines 8, one line in the upper region of each container 1a, 1b, 1c, 1d, and the other line 8 in the lower region of each container 1a, 1b, 1c, 1d, and 1le connecting the respective container 1a, 1b, 1c, 1d, and 1le to the heat transfer circuit 13. A valve 6 is provided in each line 8, allowing the containers 1a, 1b, 1c, 1d, and 1le to be controlled sequentially and / or in parallel.

[0058] The heat transfer medium 3 can be extracted from the thermally charged containers 1 and fed into a heat transfer circuit 13. Simultaneously, the next container 1 to be loaded can be pre-filled with cold heat transfer medium 12, see Fig. 1. The heat transfer zone 4 can be passed through the containers 1a, 1b, 1c, 1d, 1le sequentially, in any order, in particular from left to right in the illustration. The order in which the containers 1a, 1b, 1c, 1d, 1le are loaded or unloaded is arbitrary, provided that at least three of the containers 1a, 1b, 1c, 1d, 1le are used simultaneously.

[0059] Advantageously, this operating mode eliminates the need for an expansion tank for the heat transfer medium 3. Furthermore, it advantageously enables a continuous loading mass flow.

[0060] In the case of large-scale dual-fuel storage systems, the use of the costly heat transfer medium 3 can be further reduced by using several containers 1a, 1b, 1c, 1d, le, ... if only container 1, which contains the heat transfer zone 4, is completely filled with the medium. This corresponds to the first container 1a in Fig. 1. For continuous operation, at least three containers 1a, 1c, 1b are required.

[0061] Fig. 1 shows a possible embodiment, in which in particular the number of containers 1 can be adapted to a desired capacity.

[0062] A loading process for storage can proceed as follows: The heat transfer zone 4 is located in container 1a in the state shown. The heat transfer medium 3 flows from the cold side of container 1a (lower region of container 1a) via lines 8, in particular pipes, a pump 9, through a heat exchanger 5, which is designed as a loading and unloading heat exchanger, and is returned to the hot side of container 1a (upper region of container 1a). The heat transfer zone 3 moves from top to bottom through container 1a or through the solid bed 2, which can be, for example, granules or similar. Heat is transferred from the heat transfer medium 3 to the solid bed 2. Advantageously, only one container is used for the flow of the heat transfer medium 3.

[0063] Once the first container 1a is thermally charged, the heat transfer medium 3 is supplied to another container 1, in the illustration, the second container 1b. The second container 1b, which is subsequently to be thermally charged, is pre-filled via the pumping system 7a with cold heat transfer medium 3, 12, which is taken from the cold side of the first container 1a. The second container 1b can be partially or completely pre-filled.

[0064] Simultaneously, the quantity taken from the first container 1a is drawn from the previously fully thermally charged container 1c below and fed to the first container 1a currently in operation at the top. This is done via the transfer pumping system 7b.

[0065] In all further containers 1, there is preferably only the solid fill 2 and no heat transfer medium 3. The solid fill 2 of the further containers 1 is either thermally charged, as in container I1, or discharged, as in container Id.

[0066] The described procedure allows for continuous loading and unloading without interruption, while minimizing the required amount of heat transfer medium 3. The required amount corresponds in particular to the volume of two containers 1, minus the volume of the solid material.

[0067] The order in which the existing containers 1, or container segments, are loaded can be chosen arbitrarily.

[0068] For storage, the flow direction of the heat transfer circuit 13 is preferably reversed. Accordingly, the flow direction of the pumping systems 7a, 7b can also change.

[0069] Fig. 1b shows an energy storage device 10 during discharge in one possible embodiment. A discharge process for storing energy can proceed as follows:

[0070] In the depicted situation, the heat transfer zone 4 is located in the first container 1a. The heat transfer medium 3 flows from the hot side (upper region of container 1a) of the first container 1a via lines 8, in particular pipes, to the pump 9, through the heat exchanger 5, which is designed as a charging and discharging heat exchanger, and is returned to the cold side of the first container 1a (lower region of container 1a). The heat transfer zone 3c moves from bottom to top through container 1a, or rather through the solid bed 2. In this process, heat is transferred from the solid bed 2 to the heat transfer medium 3.

[0071] Advantageously, during discharge only one container 1 is permeated with the heat storage medium 3, namely the container that is currently being discharged.

[0072] If the first container 1a in Fig. 2 is thermally discharged, the heat transfer medium 2 is supplied to another container 1, in Fig. 2 the second container 1b. The container 1b, which is subsequently to be thermally discharged, is pre-filled from below with hot heat transfer medium 3, 11 via the transfer system 7b. This hot medium is taken from the hot side (upper region of container 1a) of the container 1a currently engaged, via the hot pumping system 7a. Simultaneously, the quantity taken from the container 1a currently engaged is drawn from the bottom of the previously completely thermally discharged container 1c and supplied to the bottom of the container 1a currently engaged. This is done via the transfer system 7a.

[0073] During unloading, all other containers 1 preferably contain only the solid bulk material 2 and no heat transfer medium 3. The solid bulk material 2 is either thermally loaded (container Id.) or unloaded (container Id.).

[0074] For ventilation and / or venting, in one embodiment a volume equalization can take place, for example, between the containers, wherein the containers are in particular connected by an equalization line 14, Fig. 1.

[0075] Fig. 3 shows a temperature profile in a container 1, which is designed as a two-component storage tank. A solid bed is arranged in the container (not shown). The cold medium 12 is located in the lower part of the container 1, and the hot medium 11 in the upper part. The heat transfer zone 4 is located between them. The right-hand side of the illustration shows an example of a temperature distribution T over a height H.

[0076] Although the present invention has been fully described above with reference to preferred embodiments, it is not limited thereto, but can be modified in a variety of ways. In particular, the number of containers 1 can vary, and in particular, three to one hundred containers 1 can be used. Other numbers are also conceivable. Furthermore, the piping system or the pipes 8 and / or the heat transfer circuit and / or the pumping systems can be configured differently from the representations in Figures 1 and 2.

Claims

Patent claims 1. A method for thermal energy storage with at least three containers (1a, 1b, 1c), each filled with a bed of solids (2), wherein a heat transfer medium (3) is introduced into a first container (1a) for storing or withdrawing thermal energy, wherein a second container (1b) is at least partially pre-filled with cold heat transfer medium (3) from the first container (1a) before storage or at least partially pre-filled with hot heat transfer medium (3) from the first container (1a) before withdrawal, wherein hot heat transfer medium (3) is supplied to the first container (1a) during storage or cold heat transfer medium (3) is supplied from a third container (1c) during withdrawal, wherein a heat transfer zone (4) is passed through the first container (1a) during storage or withdrawal.and, after complete loading or unloading from the first container (1a), is transferred to the second container (1b), thus enabling a continuous loading or unloading mass flow.

2. Method according to claim 1, characterized in that only the container (1a) is completely filled with heat transfer medium (3) in which the heat transfer zone (4) is currently located.

3. Method according to one of the preceding claims, characterized by the fact that a cold heat transfer medium is used during storage. (3) from the first container (1a) to a heat exchanger (5) hot heat transfer medium (3) is supplied from the heat exchanger (5) to the first container (1a) while the heat transfer zone (4) moves through the first container (1a), or that during discharge hot heat transfer medium (3) is supplied from the first container (1a) to the heat exchanger (5) and cold heat transfer medium (3) is supplied from the heat exchanger (5) to the first container (1a) while the heat transfer zone (4) moves through the first container (1a).

4. Method according to claim 3, characterized in that the at least three containers (1a, 1b, 1c) are successively connected to the heat exchanger (5) during storage or discharge.

5. Method according to one of claims 3 or 4, characterized by the fact that the at least three containers (1a, 1b, 1c) are connected via valves (6) are connected to the heat exchanger (5), wherein at least one valve (6) is arranged on opposite sides of each container (1a, 1b, 1c), wherein by opening two valves (6) the heat transfer medium (3) can be directed from the container (1a, 1b, 1c) to the heat exchanger (5) and back to the container (1a, 1b, 1c).

6. Method according to one of the preceding claims, characterized in that pressure equalization takes place between the containers (1a, 1b, 1c) during storage and / or storage.

7. Method according to one of the preceding claims, characterized in that the containers (1a, 1b, 1c) are connected to each other via at least one transfer pumping system (7).

8. Method according to claim 6 or 7, characterized in that the containers (1a, 1b, 1c) are connected to each other via two transfer systems (7a, 7b), wherein a first transfer system (7a) is filled with cold heat transfer medium (3) and a second transfer system (7b) is filled with hot heat transfer medium (3).

9. Method according to one of the preceding claims, characterized in that during the storage of the first container (1a), hot heat transfer medium (3) is introduced from below from the third container (1c) into the top of the first container (1a), and simultaneously cold heat transfer medium (3) is introduced from below from the first container (1a) into the bottom of the second container (1b), wherein the heat transfer zone (4) is guided from top to bottom through the first container (1a).

10. Method according to one of the preceding claims, characterized in that during the emptying of the first container (1a), cold heat transfer medium (3) is introduced from below from the second container (1b) into the first container (1a), and simultaneously hot heat transfer medium (3) is introduced from above from the first container (1a) into the third container (1c), wherein the heat transfer zone (4) is guided from bottom to top through the first container (1a).

11. Method according to one of claims 9 or 10, characterized in that the second container (1b) is loaded or unloaded analogously to the first container (1a), wherein heat transfer medium (3) is supplied to or removed from the first container (1a) and a fourth container (1d), and subsequently, loading into the fourth container (1d) can take place.

12. Method according to one of the preceding claims, characterized in that a volume of two containers (1) of heat transfer medium (3) is provided.

13. Method according to one of the preceding claims, characterized by the fact that three to 15 containers (1), in particular 5 to 10 containers (1), preferably ten containers (1) are included, wherein the heat transfer zone (4) is passed through all containers (1).

14. Thermal energy storage device (10), in particular for carrying out a method according to one of the preceding claims, comprising at least three containers (1a, 1b, 1c) each filled with a solid bulk (2), wherein the containers (1a, 1b, 1c) are connected to each other in such a way that a heat transfer medium (3) for storing and / or discharging thermal energy can be successively introduced into and / or discharged from the containers (1a, 1b, 1c) such that a heat transfer zone (4) can be sequentially passed through the containers (1a, 1b, 1c) and a continuous charging mass flow or discharging mass flow can be formed.

15. Energy storage device according to claim 14, characterized in that the at least three containers (1a, 1b, 1c) are each connected to a heat exchanger (5) via at least two valves (6), such that cold heat transfer medium (3) can be withdrawn from one side of each container (1a, 1b, 1c) and hot heat transfer medium (3) can be introduced into each container (1a, 1b, 1c) successively, or vice versa.

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