Heat storage apparatus, heat storage system having one or more heat storage apparatuses, and solar power plant having a plurality of heat storage apparatuses

Abstract

A heat storage apparatus (1) for sensible heat storage, having bulk material (3) composed of heat storage material, having thermal insulation at least laterally surrounding the bulk material (3) composed of heat storage material, and having at least one fluid outlet apparatus (17), which is positioned above the bulk material (3), for outputting heat transfer medium, wherein guiding structures (13) are arranged in the bulk material (3) and / or at edge regions of the bulk material (3), the guiding structures having laterally protruding support regions (19) for the bulk material (3), the support regions extending into the bulk material (3), wherein, in the state filled with bulk material (3), bulk material (3) rests on the support regions (19) and, below the support regions (19), cavities (3a) are formed in the bulk material (3).

Description

[0001] Heat storage device, heat storage system with one or more heat storage devices and solar power plant with several heat storage devices

[0002] The present invention relates to a heat storage device for sensible heat storage, a heat storage system with one or more such heat storage devices and a solar power plant with at least one such heat storage device.

[0003] Thermal energy storage or heat storage systems are known for various modes of operation. In addition to so-called sensible heat storage, there are latent heat storage and thermochemical heat storage systems.

[0004] Sensible heat storage systems, for example, are operated with molten salt. Molten salt heat storage systems are used in solar thermal power plants, for example, and typically have two tanks containing molten salt. The cold tank stores the unheated salt, and a hot tank stores the solar-thermally heated salt. When the heat storage system is loaded and unloaded, the fill levels in the tanks change, while the temperature in each tank remains virtually constant.

[0005] Such heat storage systems typically use so-called solar salt (a mixture of 60 wt% sodium nitrate and 40 wt% potassium nitrate). Since the thermal energy is stored in the volume of the solar salt, the known system requires a considerable amount of solar salt, which contributes significantly to the cost of the liquid salt heat storage system. Furthermore, there is always unused salt volume in the two tanks, as the tanks cannot be completely emptied during operation for technical reasons. Furthermore, the tanks must be hydrostatically stable in order to maintain the fluid pressure of the salt and must also withstand high temperatures of the heated salt. The so-called hot tank, for example, has a temperature of approximately 560°C, so stainless steel must be used for the tank walls. This results in comparatively high material costs.

[0006] Thermal stresses in the tank wall can also lead to cracks, requiring costly repairs. This makes previously known heat storage systems for sensible heat storage using solar salt very costly.

[0007] The heat storage device described above is part of the applicant's general knowledge and does not refer to a specific state of the art.

[0008] It is therefore an object of the present invention to provide an improved heat storage device for sensible heat storage that is more cost-effective than prior art heat storage devices and, moreover, is less susceptible to damage due to thermal stress. It is also an object of the present invention to provide a heat storage system with a heat storage device and a solar power plant with a heat storage device.

[0009] The heat storage device according to the invention is defined by the features of claim 1.

[0010] The heat storage system according to the invention is defined by the features of claim 16.

[0011] The solar power plant according to the invention is defined by the features of claim 19.

[0012] The heat storage device according to the invention for sensible heat storage comprises bulk material made of heat storage material, for example, basalt rubble, thermal insulation surrounding the bulk material made of heat storage material at least laterally, and at least one fluid outlet device arranged above the bulk material for discharging heat transfer medium. Guide structures are arranged in the bulk material and / or at the edge region of the bulk material, which have laterally projecting support areas for the bulk material that extend into the bulk material. When filled with bulk material, the bulk material rests on the support areas, and cavities are formed in the bulk material beneath the support areas.

[0013] Unlike the heat storage device known from the prior art, in the heat storage device according to the invention the heat is not stored in the heat transfer medium, for example in solar salt, but essentially in a bulk material made of heat storage material. The heat transfer medium is released in a heated state, for example, through a fluid outlet device and can trickle or flow through the bulk material from above. This allows heat to be released to the bulk material and stored there. To discharge the heat storage device, cold heat transfer medium can be released from above through the fluid outlet device onto the heated bulk material, so that heat is transferred from the bulk material to the heat transfer medium.

[0014] Particularly at high temperature differences between heated and cold heat transfer medium, for example of more than 200K, thermal expansion phenomena can occur in the heat storage material, which can lead to tension and abrasion or breakage of the bulk material made of heat storage material. The invention provides that guide structures are arranged in the volume of the bulk material or at edge regions of the bulk material, which have laterally protruding support areas for the bulk material that extend into the bulk material. These support areas allow the bulk material to partially arrange itself on the support areas, with cavities being formed in the bulk material beneath the support areas. The cavities create free spaces in the bulk material in which the bulk material can expand when heated by the heat transfer medium, so that tensions between grains of the bulk material cannot occur or occur to a lesser extent.When heated, the cavities can be completely or partially filled with the bulk material.

[0015] The bulk material can, for example, be granular or lumpy heat storage material. For example, grains of the bulk material can range in size from several millimeters to several centimeters.

[0016] The guide structures can also prevent the bulk material from excessively shifting during the arrangement of the bulk material during construction of the heat storage device or during operation due to temperature differences during loading and unloading of the heat storage device, so that the guide structures can hold the bulk material in position. The guide structures can also guide the heat transfer medium as it flows through the bulk material, ensuring that the heat transfer medium trickles or flows through the desired areas of the bulk material. Furthermore, areas where no molten salt should be present can be kept free of molten salt by the guide structures for thermal insulation purposes.

[0017] In contrast to the prior art, in the present invention, the heat transfer medium in the form of a fluid is not used for storing heat, but essentially as a heat transfer medium, so that the necessary volumes of the heat transfer medium are significantly reduced compared to the prior art and thus the costs of the storage system can be reduced.

[0018] Preferably, the support areas are designed as downwardly sloping plate sections. For example, the support areas can extend at an angle of between 10 and 80 degrees to the horizontal. The downward sloping design of the plate sections ensures that any heat transfer medium impinging on the plate sections can flow away, allowing further flow through the bulk material. At the same time, this allows the bulk material to rest on the plate sections of the support areas, while simultaneously creating cavities beneath the plate sections in the bulk material for its expansion.

[0019] In the heat storage device according to the invention, the heat transfer medium flows through the bulk material, preferably driven by gravity, during loading and unloading of the heat storage device. This avoids complex pump designs, for example, with an additional pump sump volume containing unused molten salt, which is necessary for pumping heat transfer medium from a tank, as is the case with the previously described salt storage tanks, thus reducing the technical complexity of the heat storage device according to the invention.

[0020] The guide structures can have wall sections extending preferably vertically through the bulk material. In this case, it can be provided in particular that wall sections at least partially surround bulk material regions and are designed to be impermeable to the heat transfer medium. In this way, it can be achieved in particular that the heat transfer medium is advantageously guided in the bulk material. For example, it can also be provided that wall sections completely surround individual bulk material regions at the sides, so that a type of channel without an edge region is formed. This has the advantage that individual bulk material regions are arranged parallel with regard to the flow of the heat transfer medium, so that the heat transfer medium only flows through specific individual bulk material regions for loading and unloading. This also makes it possible to partially load or unload the heat storage device according to the invention.Preferably at least 5, particularly preferably at least 10 to, for example, 20 bulk material areas are formed.

[0021] The invention can thus, in particular, provide for the wall sections of the guide structures to laterally enclose several bulk material regions, forming several channels, with at least one fluid outlet device arranged above each channel. In this way, individual regions can be created in the heat storage device according to the invention, which can be individually loaded or unloaded, thus also enabling partial loading or unloading of the heat storage device.

[0022] In a preferred embodiment of the invention, the guide structures have one or more end wall sections that enclose the bulk material, with insulation material being arranged on the side of the end wall section or sections facing away from the bulk material to form the thermal insulation. In other words, the guide structures can laterally enclose the bulk material by means of the end wall sections and thus hold it in position and simultaneously separate it from the insulation material. The end wall sections can have support areas for the bulk material on the side facing the bulk material. The end wall section or sections can also be impermeable to the heat transfer medium. This can prevent the heat transfer medium from penetrating the insulation material. The end wall sections can have support areas on the side facing away from the bulk material.These can be provided for the insulation material so that it is arranged partially on the support areas in a similar form to the bulk material and cavities for thermal expansion of the insulation material are formed below the support areas.

[0023] It can also be provided that the insulation material is arranged on or above the bulk material. This allows thermal insulation of the bulk material from above as well.

[0024] The insulation material can, for example, consist of a second bulk material. This can be made of the same material as the bulk material or of a different material that is particularly advantageous for the insulation function. The second bulk material can have a grain size comparable to that of the bulk material or a grain size that differs from it, for example, a finer grain size. The insulation material can be, for example, lightweight refractory bricks, glass foam, sheets with stagnant air layers, rock wool, or ceramic fiber insulation.

[0025] When arranging the second bulk material as insulation material on the bulk material, it is advantageous if the second bulk material has a similar or even larger grain size distribution than the bulk material in order to prevent the second bulk material from penetrating the bulk material.

[0026] When arranging the second bulk material as insulation material on the bulk material, it has proven particularly advantageous if the second bulk material is made of the same material as the bulk material, since then the penetration of the second bulk material into the bulk material is unproblematic.

[0027] In an embodiment of the heat storage device according to the invention, in which insulation material is arranged on or above the bulk material, it can further be provided that the at least one fluid outlet device is arranged between the insulation material and the bulk material. In other words, the insulation material is located at least partially above the at least one fluid outlet device. This prevents the heat transfer medium from penetrating the insulation material arranged above the bulk material during loading and unloading of the heat storage device.

[0028] In principle, however, a separating layer or separating device, for example a plate or a grid, can also be provided between the insulation material and the bulk material.

[0029] The heat storage device according to the invention can have a base on which the bulk material rests, wherein the base is designed to slope downwards toward a fluid extraction device. The inclination can be between 2° and 40°. This ensures that the heat transfer medium introduced into the bulk material during loading and unloading of the heat storage device flows along the base toward the fluid extraction device and can flow out of the heat storage device through the fluid extraction device.

[0030] The soil can fulfil different functions: absorption of the static load of the fill, minimisation of heat losses into the soil, whereby the soil can, for example, have a thermal insulation layer, collection of the molten salt for the fluid extraction device, which for example flows into a pipe system, as well as absorption and filtering of any abrasion of the fill, whereby the soil can, for example, have sieve structures.

[0031] The invention can advantageously provide for the heat storage device to have a tank in which at least the bulk material, the conductive structures, and the insulation material are arranged. The base can form parts of the tank.

[0032] In the heat storage device according to the invention, the base can be formed by several overlapping base plates. Thus, at least two overlapping base plates are provided, whereby thermal expansion of the base plates can be compensated for by the base plates shifting against each other in the overlapping area. In particular, it can be provided that the base plate arranged towards the fluid extraction device is arranged below a base plate arranged further up, so that heat transfer medium flowing off the base plates cannot get under one of the base plates. Alternatively, other constructions for expansion can also be used, e.g. expansion joints with channels for collecting the molten salt.

[0033] The floor panels are preferably made of steel

[0034] The tank can have a surrounding tank wall and a tank roof, with external thermal insulation arranged on the outside of the tank wall and / or the tank roof. The tank can thus protect the bulk material, the conductive structures, and the insulation material from external influences. Furthermore, the tank can have external thermal insulation, which provides additional thermal insulation. The external thermal insulation can be made of rock wool, for example. A so-called "cladding" can be provided surrounding the external thermal insulation as weather protection.

[0035] In the heat storage device according to the invention with a tank, it can basically be provided that the tank is designed to be "wide", ie that the diameter D in the horizontal direction is greater than the height H. For example, D / H > 2 can apply. In this case, it is advantageous if the guide structures have wall sections that are arranged in the bulk material and partially surround bulk material areas, as well as end wall sections that surround the bulk material.

[0036] In principle, it is also possible for the tank to be "high", i.e., the diameter D is less than the height H. For example, H / D > 2 may apply. In this case, it is advantageous if the guide structures essentially comprise end wall sections that laterally enclose the bulk material, with insulation material preferably being arranged between the end wall sections and the surrounding tank wall.

[0037] The tank wall can be formed from several sections, each having a different wall thickness, with the wall thicknesses of the sections decreasing from the bottom towards the tank roof. In other words, the section on the bottom has the greatest wall thickness and the sections arranged on it each have a smaller wall thickness than the section below it. Since the static load is lower in the upper region than near the bottom, the necessary stability can be provided in a structurally advantageous way, while at the same time material savings can be achieved on the tank wall because smaller wall thicknesses are used in the upper regions where the static load is lower. It is preferably provided that the at least one fluid outlet device has an outlet valve and fluid distribution device.By means of the fluid distribution device, the heat transfer medium exiting the outlet valve can be distributed across the cross-section of the bulk material, so that it can flow essentially evenly through the bulk material. The provision of an outlet valve in combination with the fluid distribution device has the advantage that, unlike, for example, when using a nozzle, heat losses can be kept to a minimum. If there are multiple fluid outlet devices, these can be advantageously controlled when using outlet valves. Since very hot heat transfer medium can also exit through the fluid outlet device, the use of outlet valves also offers a structurally advantageous solution for such a high-temperature application. Alternatively, the fluid outlet device can be connected to a pipeline with an external valve and have a salt distributor.

[0038] The tank walls, tank lid, and base plates can be made of metal. The conductive structures can also be made of metal, for example, as sheets or plates.

[0039] As an alternative to using a tank, the bulk material can be contained in a single volume with guide structures arranged therein. This has the advantage that expensive tank constructions are unnecessary and the bulk material is easily accessible (e.g. for repairs). A slope of the bed can be used at the side. Support structures (e.g. metal grids) can also be used to keep the slope steep and thus the amount of bulk material used to a minimum. The guide structures within the single volume ensure that no molten salt escapes from the side of the bulk material. The single volume of the bed can be covered with simple, non-pressure-resistant thermal insulation (e.g. rock wool). Suitable weather protection can be provided outside the thermal insulation, e.g. cladding or a self-supporting hall.

[0040] The invention further relates to a heat storage system with one or more heat storage devices according to the present invention.

[0041] In a heat storage system with multiple heat storage devices, at least some of the heat storage devices can be arranged in parallel with respect to the flow of the heat transfer medium. Such a heat storage system is particularly advantageous when using heat storage devices with highly designed tanks, i.e., where H / D > 2.

[0042] For example, the heat storage system according to the invention can be used for heat storage in conventional power plants, with thermal energy being introduced via a heat exchanger to heat the heat transfer medium or an electric heater, and discharged via a heat exchanger to transfer thermal energy from the heat transfer medium. For example, the heat storage system according to the invention can be used to convert electricity into heat to be stored and, after discharge, to convert it back into electricity, for example, via a conventional steam cycle. The stored heat can also be used as industrial heat after discharge.

[0043] The invention further relates to a solar power plant with at least one heat storage device. It can be provided that at least one solar radiation receiver heats the heat transfer medium and at least one heat exchanger is provided for transferring thermal energy from the heat transfer medium.

[0044] The heat storage system or solar power plant can also be provided with a buffer storage for heated heat transfer medium and a buffer storage for cold heat transfer medium. The heat exchangers can advantageously be used to charge and discharge the heat storage device. The buffer storage for heated heat transfer medium and cold heat transfer medium ensure that there is sufficient heat transfer medium for the circuit during charging and discharging of the heat storage device. Furthermore, charging and discharging can be decoupled from the storage operation (e.g. for start-up processes, shut-down processes, partial loads), since the buffer storage provides molten salt at the required temperature without any time delay. Furthermore, due to the thermocline storage process, the temperature of the escaping salt can rise at the end of the charging process and fall at the end of the discharging process.The buffer storage tanks can be designed to be suitably large in order to minimize impacts on the other parts of the heat storage system or the solar power plant.

[0045] The invention is explained in more detail below with reference to the following figures.

[0046] They show:

[0047] Figure 1 is a schematic sectional view of a first embodiment of a heat storage device according to the invention,

[0048] Figure 2 is a sectional view in plan view of the heat storage device according to Figure 1,

[0049] Figure 3 is a schematic sectional view of a second embodiment of a heat storage device according to the invention, and

[0050] Figure 4 is a schematic diagram of a heat storage system according to the invention.

[0051] Figures 1 and 2 show schematic sectional views of a first embodiment of a heat storage device 1 according to the invention. The heat storage device 1 according to the invention for sensible heat storage comprises a bulk material 3 made of heat storage material, which may, for example, be basalt rubble. The heat storage device 1 comprises a tank 5 with a surrounding tank wall 7 and a tank roof 9. Furthermore, a base 11 is provided, on which the bulk material 3 rests. Guide structures 13 are arranged in the bulk material 3 and surrounding the bulk material. The guide structures 13 have wall sections 13a extending vertically through the bulk material and end wall sections 13b. The end wall sections 13b surround the bulk material 3 laterally. On the side facing away from the bulk material 3, insulation material 15 is arranged, which forms thermal insulation.The insulation material 15 can be designed as a second bulk material and, for example, consist of the same material as the first bulk material 3.

[0052] Above the bulk material 3, several fluid outlet devices 17 for discharging heat transfer medium are arranged, via which heat transfer medium can be discharged, which can flow through the bulk material 3 made of heat storage material.

[0053] The guide structures 13 have support areas 19 on which the bulk material 3 can rest. The support areas 19 are designed as plate sections that slope downwards. When filled with bulk material 3, cavities 3a are formed beneath the support areas 19, creating space for thermal expansion of the bulk material 3.

[0054] The floor 11 is formed by several overlapping floor plates 11a, whereby the floor plates 11a can slide into the overlapping area upon thermal expansion of the floor plates 11a.

[0055] A pressure-resistant thermal insulation and sliding layer 20 is formed beneath the base plates 11a, which can absorb the weight of the bulk material 3 and simultaneously provide thermal insulation downwards. The base 11 slopes downwards toward a fluid extraction device 21 and is designed in a quasi-funnel shape. The fluid extraction device 21 ends in a collecting trough for the heat transfer medium. The heat transfer medium, which flows through the bulk material 3, reaches the base 11, flows toward the fluid extraction device 21, and is collected in the collecting trough.

[0056] To charge the heat storage device 1 according to the invention, heated heat transfer medium is discharged through the fluid outlet devices 17 and flows through the bulk material 3 before flowing through the fluid removal device 21 into the collecting trough. The thermal energy contained in the heat transfer medium is transferred to the bulk material and stored therein. To remove the thermal energy, cold heat transfer medium is discharged in the same way through the fluid outlet devices 17 and flows through the bulk material 3, absorbing thermal energy from the bulk material 3.

[0057] The wall sections 13a and the end wall sections 13b of the guide structures 13 are designed to be impermeable to the heat transfer medium, so that channels are formed in the bulk material 3 through which the heat transfer medium can flow. A fluid outlet device 17 is arranged above each of the channels. By introducing heat transfer medium through only some of the fluid outlet devices 17, the bulk material 3 is heated or cooled only in the corresponding channels, thus enabling partial loading or unloading of the heat storage device 1 according to the invention.

[0058] The tank wall 7 is formed from several sections 7a, which have a decreasing wall thickness from the bottom 11 toward the tank roof 9. This allows the static load to be advantageously absorbed by the bulk material 3 and the insulation material 15, while simultaneously achieving material savings. Since the static load is lower in the upper region of the tank wall 7, the sections can be designed with a thinner wall thickness. Arranged outside the tank wall 7 are thermal outer insulation 23, made of rock wool, for example, and a cladding 25 for weather protection.

[0059] The fluid outlet devices 17 each comprise an outlet valve 17a and a fluid distribution device 17b. The outlet valve 17a can be advantageously controlled, and the heat transfer medium exiting the outlet valve 17a is distributed by the fluid distribution device 17b so that it can enter the bulk material 3 in a distributed manner over a large area. The fluid distribution device 17b can, for example, be a type of grid.

[0060] The heat storage device 1 shown in Figs. 1 and 2 has a tank 5 which is wide, that is to say that it has a diameter D which is substantially larger than a height H.

[0061] Fig. 3 shows a schematic sectional view of a second embodiment of a heat storage device 1 according to the invention. The heat storage device 1 shown in Fig. 3 is constructed similarly to the heat storage device 1 shown in Figs. 1 and 2. However, the heat storage device 1 shown in Fig. 3 has a tank 5 that is "high," i.e., the height H is significantly greater than the diameter D. The bulk material 3 is arranged within the tank 5, with the guide structures 13 having only end wall sections 13b that surround the bulk material 3. On the side of the guide structures 13 facing the bulk material 3, the support areas 19 for the bulk material 3 are arranged, which protrude obliquely downward from the end wall sections 13b. The bulk material can partially rest on the support areas 19, so that cavities 3a are formed in the bulk material below the support areas 19.On the side of the end wall sections 13b facing away from the bulk material, insulating material 15 is arranged to form the thermal insulation, which is thus located between the end wall sections 13b and the tank wall 7. The embodiment of a heat storage device 1 according to the invention shown in Fig. 3 can be provided in a plurality of heat storage systems 100 according to the invention. A schematic diagram of the heat storage system according to the invention is shown in Fig. 4. Several heat storage devices 1 according to the invention are connected in parallel in a circuit for the heat transfer medium.

[0062] The heat transfer medium is heated via a heat exchanger 110 for heating the heat transfer medium and fed to the heat storage devices 1 to charge them. The cooled heat transfer medium is returned and circulates again.

[0063] To discharge the heat storage devices 1, cold heat transfer medium is supplied to them. The heat transfer medium heated by the heat storage devices 1 is supplied to a heat exchanger 120 for transferring thermal energy from the heat transfer medium. For example, the heat exchanger 120 for transferring thermal energy from the heat transfer medium can be an evaporator to which a water-steam circuit is connected. After the heat transfer medium has cooled in the heat exchanger 120 for transferring thermal energy from the heat transfer medium, the heat transfer medium is again supplied to the heat storage devices 1.

[0064] Valves 115 can regulate the flow to the heat storage devices 1, so that only individual ones of the heat storage devices 1 can be used.

[0065] The heat exchanger 110 for heating the heat transfer medium and the heat exchanger 120 for transferring thermal energy from the heat transfer medium are arranged parallel to each other. Furthermore, a buffer storage 140 for heated heat transfer medium is arranged between the heat storage devices 1 and the heat exchanger 120 for transferring thermal energy, and a buffer storage 130 for cold heat transfer medium is arranged between the heat storage devices 1 and the heat exchanger 110 for heating the heat transfer medium. The buffer storages 130, 140 ensure that sufficient heat transfer medium is available for the circuit during the loading and unloading of the heat storage device, and in particular for the heat exchangers 110, 120.

[0066] One or more heat storage devices 1 according to the invention can also be part of a solar power plant, so that the heat transfer medium can be heated in one or more solar radiation receivers instead of in the heat exchanger 110 for heating the heat transfer medium.

[0067] The heat storage device 1 according to the invention does not necessarily have to have a tank. In principle, a design without a closed tank is also possible, in which case support structures (e.g., metal grids), walls, or the guide structures hold the bulk material and / or the thermal insulation.

[0068] Reference symbol list

[0069] Heat storage device bulk material a cavities

[0070] tank

[0071] Tank wall a shots

[0072] Tank roof 1 Floor 1a Floor plates 3 Guide structures 3a Wall sections 3b End wall sections 5 Insulation material 7 Fluid outlet device 7a Outlet valve 7b Fluid distribution device 9 Support areas 0 Sliding layer 1 Fluid extraction device 3 Thermal external insulation 5 Cladding 00 Heat storage system 10 Heat exchanger 15 Valves 20 Heat exchanger 30 Buffer storage 40 Buffer storage

Claims

Patent claims 1. Heat storage device (1) for sensible heat storage with bulk material (3) made of heat storage material, with thermal insulation surrounding the bulk material (3) made of heat storage material at least laterally and with at least one fluid outlet device (17) arranged above the bulk material (3) for dispensing heat transfer medium, wherein guide structures (13) are arranged in the bulk material (3) and / or at edge regions of the bulk material (3), which guide structures have laterally projecting support regions (19) for the bulk material (3) extending into the bulk material (3), wherein when filled with bulk material (3), the bulk material (3) rests on the support regions (19) and cavities (3a) are formed in the bulk material (3) beneath the support regions (19).

2. Heat storage device according to claim 1, characterized in that the support areas (19) are designed as plate sections running obliquely downwards.

3. Heat storage device according to claim 1 or 2, characterized in that the guide structures (13) have wall sections (13a) extending preferably in a vertical direction through the bulk material (3).

4. Heat storage device according to claim 3, characterized in that the wall sections (13a) at least partially surround bulk material areas and are impermeable to the heat transfer medium.

5. Heat storage device according to one of claims 1 to 4, characterized in that the guide structures (13) have one or more end wall sections (13b) which enclose the bulk material (3) at least laterally, wherein at the side of the bulk material (3) Insulating material (15) is arranged on the side facing away from the end wall section (13b) or the end wall sections (13b) to form the thermal insulation.

6. Heat storage device according to one of claims 1 to 5, characterized in that insulation material (15) is arranged above or on the bulk material (3).

7. Heat storage device according to one of claims 5 or 6, characterized in that the insulating material (15) consists of a second bulk material.

8. Heat storage device according to one of claims 1 to 7, characterized by a base (11) on which the bulk material (3) rests, wherein the base (11) is designed to slope down towards a fluid removal device (21).

9. Heat storage device according to claim 8, characterized in that the base (11) is formed by several overlapping base plates (11a).

10. Heat storage device according to one of claims 1 to 9, characterized by a tank (5) in which at least the bulk material (3), the conductive structures (13) and the insulating material (15) are arranged.

11. Heat storage device according to claim 10, characterized in that the tank (5) has a surrounding tank wall (7) and a tank roof (9), wherein a thermal external insulation (23) is arranged on the outside of the tank wall (7) and the tank roof (9).

12. Heat storage device according to one of the preceding claims, characterized in that the circumferential tank wall (7) is formed from several sections (7a), each having a different wall thickness, wherein the wall thicknesses of the sections (7a) decrease from the bottom (11) towards the tank roof (9).

13. Heat storage device according to one of claims 6 to 12, characterized in that the at least one fluid outlet device (17) is arranged between the insulation material (15) and the bulk material (3).

14. Heat storage device according to one of claims 1 to 13, characterized in that the at least one fluid outlet device (17) has an outlet valve (17a) and a fluid distribution device (17b).

15. Heat storage device according to one of the preceding claims, characterized in that the wall sections (13a) of the guide structures (13) laterally enclose a plurality of bulk material regions, wherein a plurality of channels are formed, wherein in each case at least one fluid outlet device (17) is arranged above one of the channels.

16. Heat storage system (100) with one heat storage device (1) or several heat storage devices (1) according to one of claims 1 to 15.

17. Heat storage system according to claim 16, characterized in that at least some of the plurality of heat storage devices (1) are arranged in parallel with respect to a flow of the heat transfer medium 18. Heat storage system according to claim 16 or, characterized by at least one heat exchanger (110) for heating the heat transfer medium, and at least one heat exchanger (120) for transferring heat energy from the heat transfer medium and / or by a buffer storage (140) for heated heat transfer medium and a buffer storage (130) for cold heat transfer medium.

19. Solar power plant with at least one heat storage device (1) according to one of claims 1 to 15.

20. Solar power plant according to claim 19, characterized by at least one solar radiation receiver for heating the heat transfer medium, and at least one heat exchanger (120) for transferring thermal energy from the heat transfer medium.

21. Solar power plant according to claim 19 or 20, characterized by a buffer storage (140) for heated heat transfer medium and a buffer storage (130) for cold heat transfer medium.

Images