Enclosure for heat storage and corresponding set of construction elements of enclosures for heat storage

Abstract

A thermal storage enclosure (1), and a corresponding set of construction elements (2, 4, 6, 11, 12, 19, 21) for thermal storage enclosures, comprising a thermally insulated (9) cylindrical outer wall (6) fixed to a base (2) anchored to foundations (8), and closed by a lid (4), suitable for connection via heat transfer gas outlets (3, 5) to a renewable electricity generation storage system. An inner part (7), comprising a liner (21) not connected to the outer wall (6), forms a floating structure made up of several layers of a thermal storage material (10) separated by metal grids (11, 19) supported without fixed connection by interlocking tubular segments (12). All the constituent elements (2, 4, 6, 11, 12, 19, 21) are factory-made and easily transportable as a kit for simplified assembly without specific equipment or manpower.

Description

TECHNICAL FIELD OF THE INVENTION.

[0001] The present invention relates to a thermal storage enclosure, and a set of corresponding storage enclosure construction elements. TECHNOLOGICAL BACKGROUND OF THE INVENTION.

[0002] Electricity storage represents a major challenge for the energy transition because it allows surplus renewable production to be stored and used when needed.

[0003] The reversible conversion of electricity into heat is an attractive solution for storing large amounts of energy. The advantage of this approach is its high energy density (storage capacity per unit volume or mass), and the fact that storage capacity can be easily increased by increasing the mass of material used. Since storage materials meeting the technical requirements of this technology are readily available, inexpensive, and non-polluting, this principle is particularly well-suited to high energy capacities or is more efficient than other existing solutions (electrochemical batteries, flywheels, hydrogen, etc.).

[0004] Excess electricity is therefore converted into heat and stored in a material as a temperature increase. This energy is then released by lowering the average temperature of the materials. Heat input and recovery are achieved through the forced circulation of a gas (typically air) set in motion by a set of turbomachinery (turbines, compressors), which serves as the heat transfer fluid for heat exchange.

[0005] The material is placed in enclosures for thermal insulation from the environment. The storage materials that can be used are either natural (e.g., basalt rocks) or industrially produced from minerals (e.g., ceramics or refractory materials). Inside each enclosure, the material is heated from above and cooled from below. Considering the natural stratification between the hot and cold gases, this leads to the formation of a "thermal front," that is, a transition zone between the "high" temperature at the top of the enclosure and the "low" temperature at the bottom. For the process to function correctly, this front must be as narrow as possible and remain as horizontal as possible.For this, it is advantageous to have several separate layers of storage material, each separated from the next by an air gap allowing the front not to become unstable.

[0006] A thermal energy storage system is described, for example, in US patent US4405010. In this system, the thermal storage unit is a single unit in the form of a cylindrical housing with an inlet and outlet for airflow. This housing is filled with a refractory material forming layers separated, for example, by metal rods supported by the walls of the housing.

[0007] This monolithic structure is simple; however, it is not suitable for enclosures with a large energy capacity because this would necessitate the design of reinforced walls to withstand the lateral and vertical forces exerted by the rods and the corresponding large volume of material. US 2012 / 279679 A1 discloses a thermal storage enclosure according to the preamble of claim 1.

[0008] The areas most suitable for deploying large-scale energy storage capacity are often isolated. These areas frequently have weak electrical grids and rely heavily on electricity generated from fossil fuels (particularly fuel oil). The deployment of renewable energy sources therefore follows a logic of reducing energy dependence on fossil fuels, lowering energy bills, and decreasing the carbon footprint of the electricity sector. However, the penetration of low-carbon energy is limited because it is necessary to ensure electricity supply regardless of weather conditions. These areas are thus well-suited to the development of energy storage as a replacement for thermal power generation.

[0009] However, it can be problematic to transport installations including monobloc thermal storage enclosures of the type described in US patent 4405010 to isolated locations, as they may be difficult to access.

[0010] To overcome these drawbacks, there is therefore a primary need for a thermal storage enclosure with a lightweight and optimized structure to facilitate its transport.

[0011] Furthermore, finding specific equipment or labor in these remote locations can be difficult if the assembly is complex. Therefore, there is also a secondary need for a set of specific storage enclosure construction components to simplify their construction and assembly. GENERAL DESCRIPTION OF THE INVENTION.

[0012] The aim of the present invention is therefore to satisfy these needs by producing a thermal storage enclosure of the type extending substantially vertically and having an external part comprising a lower part provided with at least one first intake of a heat transfer fluid, an upper part provided with at least one second intake of this fluid and an intermediate part of substantially cylindrical shape enveloping an internal part comprising one or more substantially horizontal layers of a thermal storage material supported by separation means extending substantially horizontally.

[0013] According to the invention, this internal part remarkably forms a floating structure.

[0014] The separation means are formed, according to the invention, of one or more perforated plates supported by at least three vertical supports resting on foundations external to the external part.

[0015] The lower part of the thermal storage enclosure also rests on these foundations.

[0016] According to the invention, the plates and supports are advantageously provided respectively with first and second complementary inclined surfaces in contact.

[0017] According to the invention further, the supports are very advantageously made up of one or more segments of a tubular element, each having a lower end with an external dimension substantially smaller than an internal dimension of said tubular element.

[0018] Preferably, the second surfaces are formed of collars arranged at an upper end of each of the segments having a radial section inclined at an angle between 0° and 45° with respect to a horizontal plane.

[0019] In the thermal storage enclosure according to the invention, the supports are regularly distributed in tangential and radial directions of a cross-section of the floating structure and, remarkably, a vertical projection of the plates forms a tiling of the cross-section between traces of these supports.

[0020] According to the invention, each of the plates adjacent to the intermediate part is advantageously provided with a peripheral fin opposite this intermediate part cooperating internally with a lower edge of a cylindrical envelope surrounding each of the layers of the thermal storage material.

[0021] Preferably, the external part is lined internally with thermal insulation in contact with this envelope.

[0022] To more specifically satisfy the second need, a set of construction elements for thermal storage enclosures according to the invention will be used, comprising: first metal tubes having a first flared end and a second reduced end, this second end being intended to fit into the first end; a metal base substantially in the shape of a hemisphere comprising second through metal tubes each having on a concave side of this hemisphere a third end adapted to receive the second end of one of the first tubes and on a side opposite the concave side, a fourth end having a flange adapted to be fixed to an anchor, and further comprising a first opening adapted to be connected to a thermal storage system; a substantially hemispherical metal cover comprising a second opening adapted to be connected to this thermal storage system; one or more elements of metal cylinders intended to form an outer wall of these enclosures;first metal grid elements, each comprising first tabs intended to cooperate with the first end of each of the first tubes; second metal grid elements, each comprising second tabs intended to cooperate with the first end of each of the first tubes and each also comprising, in part, a peripheral rim; metal liner elements intended to cooperate with this peripheral rim; a heat storage material; a thermal insulation material intended to internally line the base, the lid and the wall of the enclosures.

[0023] These few essential specifications will have made evident to the person skilled in the art the advantages provided by the thermal storage enclosure, and the corresponding set of construction elements for storage enclosures, described above, in relation to the prior art, in terms of ease of transport, construction and assembly.

[0024] The detailed specifications of the invention are given in the following description in conjunction with the attached drawings.

[0025] It should be noted that these drawings have no other purpose than to illustrate the text of the description and do not in any way constitute a limitation of the scope of the invention. BRIEF DESCRIPTION OF THE DRAWINGS.

[0026] There Figure 1 is an axial cross-section of the thermal storage enclosure according to the invention. Figure 2 is a detailed view of zone A of the thermal storage enclosure according to the invention shown on the Figure 1 .There Figure 3 is a detailed view of zone B of the thermal storage enclosure according to the invention shown on the Figure 1 . There Figure 4 is a detailed view of zone C of the thermal storage enclosure according to the invention shown on the Figure 1 . There Figure 5 is a detailed view of zone D of the thermal storage enclosure according to the invention shown on the Figure 1 . There Figure 6 is a detailed view of zone E of the thermal storage enclosure according to the invention shown on the Figure 1 . There Figure 7 is a cross-section along FF of the thermal storage enclosure according to the invention shown on the Figure 1 . There Figure 8 schematically represents a first phase of assembly of the thermal storage enclosure according to the invention. Figure 9schematically represents a second phase of assembly of the thermal storage enclosure according to the invention. Figure 10 schematically represents a third phase of assembly of the thermal storage enclosure according to the invention. Figure 11 schematically represents a fourth phase of an assembly of the thermal storage enclosure according to the invention. DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION.

[0027] The thermal storage enclosure 1 according to the invention, generally in the shape of a cylinder extending substantially vertically, is shown in the Figure 1 in axial section.

[0028] The outer part is distinguished, comprising: the lower part 2, equipped with the first intake 3 of the heat transfer fluid, preferably air; the upper part 4, equipped with the second intake 5 of the heat transfer fluid, the intermediate part 6 of substantially cylindrical shape enveloping the internal part 7.

[0029] The lower part 2 of the enclosure 1 serves as a base and transfers the mechanical forces exerted by the internal part 7 onto the foundations 8. The first outlet 3 is suitable for connection to a pipeline of the thermal storage system.

[0030] The intermediate part 6 is preferably in one piece, or, alternatively, made up of several assembled metal cylinder elements.

[0031] The upper part 4 serves as a cover and the second socket 5 is also suitable for connection to the piping of the thermal storage system.

[0032] The intermediate part 6 is assembled with the lower part 2 and upper part 4 by bolting.

[0033] Thermal insulation 9 is fixed to the inside of the external part 2, 4, 6 in order to limit heat loss. Lightweight refractory insulation materials, such as those used in the steel, glass, and industrial furnace industries, of the calcium silicate or ceramic fiber type, are suitable for this purpose.

[0034] These refractory insulators are in particular calcium silicate bricks joined with refractory cement or flexible and glued fibrous or microporous insulating materials.

[0035] Since the thermal storage enclosure 1 is a pressurized tank, the external part 2, 4, 6 is made of steel, such as the P265GH alloy, which is standard in this use.

[0036] The thermal storage enclosures 1 according to the invention have dimensions determined according to the energy capacity sought.

[0037] In preferred embodiments of the invention, two enclosures 1, operating in a complementary manner, known per se, for a thermal storage capacity of the equivalent of approximately 4 MWh of electricity, have a volume of approximately 60 m3, a height of approximately 5 m and a diameter of approximately 4 m (i.e. a height / diameter ratio substantially equal to 1.25).

[0038] The internal part 7 preferably comprises about ten layers 10 of the thermal storage material such as alumina-rich refractory ceramics or natural materials such as basaltic rocks.

[0039] These layers 10 are separated by horizontal plates 11 supported by vertical supports 12 resting on foundations 8.

[0040] As the cross-section clearly shows ( Figure 1 )of the thermal storage enclosure 1 according to the invention, each of the vertical supports 12 is made up of segments of a tubular element.

[0041] A detailed view of area A ( Figure 2 ) shows that the lower end 13 of one of the segments 12 has a smaller cross-section so as to fit into the upper end 14 of another of the segments 12.

[0042] This upper end 14 has a collar 15 inclined at 45° to the horizontal on which the horizontal plates 11 rest by means of the complementary inclined surfaces 16 with which they are provided.

[0043] Each of the segments 12 preferably has a height of between approximately 50 and 60 cm in order to limit the weight of storage material per layer 10 and to limit the required thickness of the horizontal plates. A maximum thickness of these plates is set at 10 mm (preferably 5 mm), as these dimensions are more widely available from suppliers of semi-finished steel products (sheets in the form of plates or coils), and also because it is possible to punch steel plates of this thickness.

[0044] The flared part 14 and the reduced part 13 of the segments 12 are produced by stamping operations or, alternatively, by cold forming of cylindrical tubes.

[0045] A detailed view of area B ( Figure 3 )shows that the upper end 14 of each of the segments 12 supporting a final layer 17 of thermal storage material (10) is closed by a plug 18 preventing the storage material from entering the inside of the tubes.

[0046] The 19 examples of the plates 11 adjacent to the intermediate part 6 of the outer part of the enclosure 1 are fitted with a peripheral fin 20 opposite the thermal insulation 9 and support the liner 21 as clearly shown in the detail view of area C ( Figure 4 ).

[0047] The vertical supports 12 fit at their bases into other tubular segments 22 passing through a hemispherical part of the base 2 of the enclosure 1, as shown in the detail view of area D ( Figure 5 ), so as to transfer all the vertical forces exerted by the internal part 7 onto the foundations 8, as shown in the detailed view of area E ( Figure 6 ).

[0048] It should be noted that these other tubular segments 22 are filled with the same thermal insulation 9 as that covering the inside of the entire external part 2, 4, 6 during the assembly operation.

[0049] The base 2 is fixed to the foundations 8 by anchoring to a metal support previously poured in the concrete, chemical anchors 23 or others.

[0050] Neither the plates 19 nor the liner 21 resting on them are fixed to the intermediate part 6, but simply in contact with the thermal insulation 9: in this way the structure formed by the internal part 7 is said to be "floating".

[0051] The horizontal plates 11, 19, supported by the vertical supports 12, which retain the storage material 10, 17, cover the cross-section of the enclosure 1 in a regular pattern (hexagonal, square, triangular plates, etc.) or an irregular pattern, as shown in the Figure 7 .

[0052] Any other set of shapes covering the section of enclosure 1 is optimized according to technical constraints such as: diameter of enclosure 1, weight of storage material 10, 17, material and thickness of plates 11, 19, number of vertical supports 12...

[0053] The plates 11, 19 are placed side by side on the vertical supports 12 and are held in place by means of the inclined supports 16 cooperating with the collars 15 and the weight of the storage material 10, 17 placed on top of them.

[0054] The shape of the plates 11, 19 and the position of the vertical supports 12 under these plates 11, 19 are designed so that the center of gravity of the plates 11, 19, alone or supporting the storage material 10, 17, is always contained within their respective support surface, without having to resort to a structural link between the plates 11, 19, or between the plates 19 and the intermediate part 6.

[0055] The plates 11, 19 preferably have a thickness of about 5 mm in order to resist mechanical and thermal stresses depending on the storage material 10 used and the alloy used for their manufacture, while remaining in types of semi-finished products widely available and easily worked in the factory.

[0056] Regular perforations in the plates 11, 19 ensure airflow while retaining the storage material 10, 17, which is preferably in granular and unstructured form. The hole size is set at 80-90% of a minimum grain size of the storage material 10, 17, with a grain size between 10 and 30 mm. The surface density of the holes is set to within a few percent of the porosity of the storage material 10, 17, to facilitate airflow.

[0057] The liner 21, a thin metal casing (preferably less than 1 mm), protects the thermal insulation 9 against damage caused by contact with the storage material 10, 17 (deformation, crushing or puncture caused by the movement of the grains of the storage material 10, 17 caused by their expansion, if they were in direct contact with the thermal insulation 9)

[0058] The liner 21 also prevents the grains of the storage material 10, 17 from seeping into a space between the horizontal plates 19 and the thermal insulation 9, as clearly shown by the Figure 4 . This liner 21 has no structural function (no vertical load transfer).

[0059] All the components of the thermal storage enclosure 1 according to the invention are manufactured off-site, in a factory, using simple processes: cutting, bending, stamping, cold forming, punching, and welding for the minimum number of parts. High-precision or overly complex operations such as forging, casting, molding, or machining are not used. This simplifies the manufacturing process and therefore reduces costs.

[0060] Furthermore, these parts are advantageously manufactured in large quantities in the factory from readily available standard semi-finished products (plates, tubes, bars) in order to achieve economies of scale, and are then transported and assembled on site, thus reducing the construction time of the thermal storage enclosure 1 on site.

[0061] With the same objective of simplifying and accelerating construction, the internal and external parts do not require complex assembly during the construction of the thermal storage system installation.

[0062] The components of thermal storage enclosure 1 are easily handled using simple and widely available lifting equipment. Furthermore, these components are primarily positioned, fitted together, or screwed in manually.

[0063] The internal part 7 and external parts 2, 4, 6 are self-supporting and independent. Some connections are not rigid, which has the advantage of allowing these internal part 7 and external parts 2, 4, 6 to expand with temperature variations.

[0064] Such a modular (prefabricated parts) and simplified (simple assembly) design makes deployment of facilities faster (advance manufacturing and easy transport of complete kits), but also the deployment of these facilities without specific equipment or manpower, which is important in isolated areas, conducive to the implementation of electricity storage systems.

[0065] According to the invention, a complete kit necessary for assembling the thermal storage enclosure 1 described above, according to the procedure shown schematically on the Figures 8 to 11 , includes all of the following building elements: the first metallic tubes 24 in a number depending on the nominal thermal capacity of the enclosure 1, and having a first flared end 25 and a reduced second end 26, this second end 26 being intended to fit into the first end 25; the metallic base 2 substantially in the shape of a hemisphere, of diameter depending on the model of enclosure chosen, comprising second metallic tubes 22 through each having on a concave side of this hemisphere a third end 27 suitable for receiving the second end 26 of one of the first tubes 24 and on a side opposite the concave side, a fourth end 28 having a flange suitable for being fixed to an anchorage 23, and further comprising a first opening 3 suitable for being connected to a thermal storage system;the metal cover 4 substantially hemispherical, of diameter corresponding to that of the base 2, having a second opening 5 suitable for being connected to this thermal storage system; the metal cylinder or elements of metal cylinders intended to form the outer wall 6 of the enclosure provided 1 by bolting onto the base 2; the first metal grid elements 29, in a number corresponding to the nominal characteristics of the enclosure 1 provided, each having the first tabs 30 intended to cooperate with the first end 25 of each of the first tubes 24, by simple placement during the first assembly phase, as shown in the; Figure 8 ;the second metal grid elements, intended to be arranged opposite the outer wall 6 of the planned enclosure 1, each comprising second legs capable of cooperating with the first end of each of the first tubes 24 and each also comprising in part a peripheral rim;

[0066] The kit includes all the construction elements to iterate through the second assembly phase, up to the completion of enclosure 1, the first assembly phase being shown schematically on the Figure 8 : laying another level of first tubes 24 on the previous level of first tubes 24 and first 29 and second grid elements, as illustrated by the Figure 9 .

[0067] The kit also includes: metallic liner elements designed to cooperate with the peripheral edge of the second grid elements; a heat storage material 31 in sufficient volume to uniformly fill each level, while maintaining an air gap 32, by iterating the third and fourth phases of the planned enclosure assembly procedure 1, schematically shown respectively on the Figures 10 and 11 . a thermal insulation material intended to internally coat the base, lid and wall of the planned enclosure 1, during an initial phase of assembly.

[0068] Thus, this set of construction elements for a thermal storage enclosure 1 meets the needs of a lightweight and optimized structure to facilitate its transport, as well as a specific set to simplify its construction and assembly.

[0069] As can be expected, the invention is not limited to the preferred embodiments described above.

[0070] The thermal capacity, volume, and dimensions of storage enclosure 1 are indicative. The same applies to the dimensions of the components of storage enclosure 1 and the materials cited as examples.

[0071] The invention therefore, on the contrary, encompasses all possible embodiments within the limits of the subject matter of the following claims.

Claims

1. Thermal storage chamber(1) of the type extending substantially vertically and having an outer part (2, 4, 6) comprising a lower part (2) provided with at least one first tapping (3) for a heat-transfer fluid, an upper part (4) provided with at least one second tapping (5) for said fluid and an intermediate part (6) of substantially cylindrical shape enveloping an inner part (7) comprising one or more substantially horizontal layers of a thermal storage material (10) supported by separation means (11, 19,) extending substantially horizontally, said inner part (7) forming a floating structure, characterised in that said separation means (11, 19) are formed of one or more perforated plates supported by at least three vertical supports (12) bearing on foundations (8) external to said outer part (2, 4, 6), and in that said lower part (2) rests on said foundations (8).

2. Thermal storage chamber(1) according to the preceding claim 1, characterised in that said plates (11, 19) and said supports (12) are provided respectively with first (16) and second (15) complementary inclined surfaces in contact.

3. Thermal storage chamber(1) according to either one of the preceding claims 1 to 2, characterised in that said supports (12) consist of one or more segments of a tubular element each having a lower end (13) with an outer dimension substantially smaller than an inner dimension of said tubular element.

4. Thermal storage chamber (1) according to the preceding claim 3, characterised in that said second surfaces (15) are formed of collars (15) arranged at an upper end (14) of each of said segments having a radial section inclined by an angle of between 0° and 45° relative to a horizontal plane.

5. Thermal storage chamber(1) according to any one of the preceding claims 1 to 4, characterised in that said supports (12) are evenly distributed in tangential and radial directions of a cross-section of said floating structure (7) and in that a vertical projection of said plates (11, 19) forms a paving of said cross-section between tracks of said supports (12).

6. Thermal storage chamber(1) according to any one of the preceding claims 1 to 5, characterised in that each of said plates (19) adjacent to said intermediate part (6) is provided with a peripheral fin (20) facing said intermediate part (6) cooperating internally with a lower edge of a cylindrical envelope (21) surrounding each of said layers (10).

7. Thermal storage chamber(1) according to claim 6, characterised in that said outer part (2, 4, 6) is internally clad with a thermal insulator (9) in contact with said envelope (21).

8. Set of elements for building thermal storage chambers (1) according to any one of the preceding claims 1 to 7, comprising: - first metal tubes (24) having a first flared end (25) and a second reduced end (26), said second end (26) being intended to fit into said first end (25); - a substantially hemisphere-shaped metal base (2) comprising second through metal tubes (22) each having, on a concave side of said hemisphere, a third end (27) adapted to receive said second end (26) of an item of said first tubes (24) and, on a side opposite to said concave side, a fourth end (28) having a flange adapted to be fastened to an anchor (23), and further comprising a first opening (3) adapted to be connected to a thermal storage system; - a substantially hemispherical metal cover (4) comprising a second opening (5) adapted to be connected to said thermal storage system; - one or more metal cylinder element(s) intended to form an external wall (6) of said chambers (1); - first metal grid elements (29) each comprising first tabs (30) intended to cooperate with said first end (25) of each of said first tubes (24); - second metal grid elements each comprising second tabs intended to cooperate with said first end (25) of each of said first tubes (24) and each further comprising in part a peripheral rim (20); - metal liner elements each intended to cooperate with said peripheral rim (20); - a heat storage material (31); - a thermal insulation material (9) intended to internally line said base (2), said cover (4) and said wall (6).

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