WO2024258747A2

WO2024258747A2 - Thermal energy storage tank

Info

Publication number: WO2024258747A2
Application number: PCT/US2024/033115
Authority: WO
Inventors: Andrea Pedretti; William Tod GROSS
Original assignee: Energy Vault Inc
Current assignee: Energy Vault Inc
Priority date: 2023-06-15
Filing date: 2024-06-07
Publication date: 2024-12-19
Anticipated expiration: 2025-12-15
Also published as: WO2024258747A3

Abstract

A thermal energy storage tank may include an outer shell, a main chamber positioned within the outer shell, and a secondary chamber surrounding the main chamber and positioned within the outer shell. The main chamber may also be filled with a heat storing material and the secondary chamber may be filled with an insulating material. Additionally, the thermal energy storage tank may include one or more pipes extending through the outer shell and into the main chamber and the one or more pipes may receive a flow of heated air to heat the heat storing material.

Description

ENVLT.028WO PCT

THERMAL ENERGY STORAGE TANK

INCORPORATION BY REFERENCE TO ANY PRIORITY APPLICATIONS

[0001] Any and all applications for which a foreign or domestic priority claim is identified in the Application Data Sheet as filed with the present application are hereby incorporated by reference under 37 CFR 1.57.

BACKGROUND

Field of the Invention

[0002] The present disclosure is directed to systems and methods for storing thermal energy and more particularly to a thermal energy storage tank containing two volumes of material for thermal energy storage.

Description of the Related Art

[0003] A thermal energy storage tank can play a crucial role in a thermal energy storage system, such as a Brayton Cycle, by providing a way to store excess heat that is generated during off-peak periods that can be used later during peak demand. This helps to optimize energy consumption, reduce waste, and increase efficiency. In addition, thermal energy storage tanks can also help to mitigate the effect of power generation from renewable energy sources (e.g., solar power, wind power, hydroelectric power, biomass, etc.). Since many of these renewable energy sources can be intermittent and/or unpredictable, storing excess energy for later use in thermal energy storage tanks can improve electrical grid stability and reduce the need for backup power sources, which can reduce carbon emissions and environmental impact.

SUMMARY OF THE INVENTION

[0004] There is a need for thermal energy storage tanks that can be used to store thermal energy (e.g., generated from heated air, generated from renewable energy sources). In some examples, it can be beneficial to store energy thermal energy during the day that can be used to generate electricity at a later period (e.g., nighttime, low energy generation periods, high energy usage periods).

[0005] In accordance with one aspect of the disclosure, a thermal energy storage tank is provided with a main chamber configured to hold a heat storing material and a secondary chamber disposed about the main chamber and configured to hold an insulating material, the secondary chamber configured to insulate the main chamber to inhibit heat loss via a circumferential wall of the main chamber. The insulating material can optionally be sand, gravel or pebbles and advantageously insulates the main chamber at low cost.

[0006] In accordance with another aspect of the disclosure, a thermal energy storage tank is provided. The tank includes an outer shell and a main chamber positioned within the outer shell, wherein the main chamber is filled with a heat storing material. The tank also includes a secondary chamber surrounding the main chamber and positioned within the outer shell, wherein the secondary chamber is filled with an insulating material. The tank also includes one or more pipes extending through the outer shell and into the main chamber and can receive a flow of air, the one or more pipes being in fluid communication with the main chamber. The one or more pipes have a plurality of openings with a diameter smaller than a size of the heat storing material. The heat storing material can also be a plurality of rocks and the insulating material can be sand. Additionally, the one or more pipes extend across the main chamber and can receive a fluid. The fluid can be a liquid or a gas.

[0007] In accordance with another aspect of the disclosure, the one or more pipes can include a first pipe and a second pipe. The first pipe is vertically spaced apart from the second pipe. The first pipe is configured to receive a flow of heated air and the second pipe is configured to exhaust a flow of cooled air. The heated air can heat the heat storing material in the main chamber. The first pipe and the second pipe can be vertically space apart and laterally intersect.

[0008] In accordance with another aspect of the disclosure, the second pipe can receive a flow of ambient air and the first pipe can exhaust a flow of heated air. The heat storing material can heat the ambient air flowing through the main chamber. Additionally, the insulating material can store thermal energy.

[0009] In accordance with another aspect of the disclosure, the thermal energy storage tank includes a base portion be fixed to a ground surface. The base portion can include a plurality of supporting structures to inhibit the thermal energy storage tank from bending at a bottom portion. Additionally, the thermal energy storage tank can include a cap. The cap can cover an opening at a top end of the outer shell, where the opening at the top end of the outer shell can receive the insulating material therethrough. The thermal energy storage tank can be buried underneath a ground surface. The one or more pipes can receive a flow of heated air from a compressor. The one or more pipes can deliver a flow of heated air to a turbine to generate electricity.

[0010] In accordance with another aspect of the disclosure, the top end of the thermal energy storage tank can be hotter than a bottom end. Additionally, the second pipe can deliver the flow of ambient air to the main chamber through a plurality of openings along the second pipe. The first pipe can receive the heated air through a second plurality of openings positioned along the first pipe.

BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 is a schematic perspective view of a thermal energy storage tank.

[0012] Figure 2 is a schematic side view of a thermal energy storage tank.

[0013] Figure 3 is a schematic top view of a thermal energy storage tank.

[0014] Figure 4 is a schematic cross-sectional view of a thermal energy storage tank.

DETAILED DESCRIPTION

[0015] In accordance with one aspect of the disclosure, a thermal energy storage tank operable to store heat for thermal energy use is provided. The systems disclosed herein can describe a tank which can be used in a Brayton-based cycle which is operable to store electricity as thermal energy. The thermal energy storage tank in connection with the Braytonbased cycle can be used to store electricity as thermal energy when the system is operated in a charging mode (e.g., heated air flows through the tank to store thermal energy in the tank) and operable to generate electricity from thermal energy when the system is operated in a discharging mode (e.g., heated air flows out of the tank and used to generate electricity). Heated air can flow into the tank or out of the tank through one or more pipes positioned within the thermal energy storage tank. The thermal energy storage tank can be filled with an insulating material (e.g., sand, gravel) in an annulus that surrounds a chamber with a heat storing material (e.g., rocks, gravel, pebbles) for storing thermal energy. Advantageously, the insulating material insulates the chamber at lower cost due to the low cost of the insulating material. [0016] FIGS. 1-3 show a schematic perspective view of a thermal energy storage tank 100 for use in a thermal energy system (e.g., a Brayton based thermal energy storage system). The tank 100 can include an outer shell 102 (e.g., outer wall) which can be made of steel. Alternatively, the outer shell 102 can be made of another suitable steel alloy (e.g., carbon steel, brass, tungsten) or concrete. The interior portion of the tank 100 can have an insulating material (e.g., sand, gravel) and a heat storing or conductive material (e.g., rocks, gravel, pebbles). The outer shell 102 of the tank 100 can be cylindrically shaped and the top of the tank 100 can be dome shaped. Advantageously, designing the tank 100 to be cylindrical reduces the amount of material consumption necessary for building the tank 100 and can allow heat to distribute more uniformly throughout the tank 100. Additionally, the outer shell 102 can have one or more pipes (e.g., first pipe 110A, second pipe 110B) which can extend from outside of the outer shell 102 and into a space within the thermal energy storage tank 100. In one implementation, the first pipe 110A can be located directly above and parallel to the second pipe 110B (e.g., the first pipe 110A is above and aligned with the second pipe 110B). However, in some implementations, the one or more pipes (e.g., first pipe 110A, second pipe 110B) can be vertically spaced from each other and laterally intersect each other (e.g., the first pipe 110A is located above and extends at an angle relative to the second pipe 110B so that the first pipe 110A crosses over the second pipe 110B, for example when viewed from above). The one or more pipes (e.g., first pipe 110A, second pipe HOB) can receive a flow of air therethrough. Said air can enter the tank 100 via one of the pipes and flow out of the tank 100 and be exhausted from the tank 100 via another one of the pipes (e.g., to a compressor or turbine). For example, a flow of air (e.g., ambient air) can enter the tank 100 via the first pipe 110A and a flow of air (e.g., heated air) can exit the tank 100 via the second pipe 110B (e.g., and flow to a turbine for energy generation). In one implementation, the one or more pipes (e.g., first pipe 110A, second pipe 110B) can receive a flow of any fluid (e.g., a liquid such as water, oil, etc., a gas such as air etc.). For example, a flow of water (e.g., ambient fluid) can enter the tank 100 via the first pipe 110A and a flow of water (e.g., ambient fluid) can exit the tank 100 via the second pipe HOB.

[0017] The first pipe 110A and the second pipe 110B can have a plurality of small holes or openings (e.g., openings 112B, 114B shown in FIG. 4). The openings 112B, 114B can permit air or a fluid to flow in and out of the one or more pipes (e.g., first pipe 110A, second pipe HOB) and through the tank 100. Advantageously, the openings 112B, 114B can be sized such that air can flow in and out of the one or more pipes (e.g., first pipe 110A, second pipe HOB) while inhibiting (e.g., preventing) the heat storing material (e.g., rocks, gravel, pebbles) within the tank 100 from entering the one or more pipes (e.g., first pipe 110A, second pipe 110B) via the openings 112B, 114B, thereby inhibiting (e.g., preventing) the heat storing material from obstructing the flow of air and/or clogging the one or more pipes (e.g., first pipe 110A, second pipe 110B). For example, the size of the holes or openings 112B, 114B can be smaller than a diameter of the heat storing material (e.g., rocks, pebbles, gravel). Additionally, since the openings 112B, 114B are located within the main chamber 104 (see FIG. 4) the insulating materials in the secondary chamber 106 (see FIG. 4) will not obstruct the one or more pipes. Therefore, the insulating materials will not prevent air from flowing in and out of the tank 100.

[0018] With continued reference to FIGS. 1-3, the thermal energy storage tank 100 can have a base portion 130 or skirt fixed (e.g., bolted, adhered to) to a ground surface G. Additionally, the base portion 130 or skirt can have a plurality of supporting structures 132 or flanges which can provide structural support to base portion 130 or skirt and which can inhibit (e.g., prevent) the outer shell 102 from bending, warping, or flexing around the bottom of the thermal energy storage tank 100. The tank 100 can have a cap 108 located at or proximate a top end of the tank 100. The cap 108 can cover an opening at or proximate the top end of the tank 100. The cap 108 can be removed from the thermal energy storage tank 100 to allow a user or operator to access an interior portion of the tank 100. In one implementation, the insulating material can be delivered into the tank 100 via the opening under the cap 108 (e.g., once the cap 108 is removed).

[0019] FIG. 4 shows a cross-sectional view of the thermal energy storage tank 100 for use in a thermal energy system. The thermal energy storage tank 100 can include a main chamber 104 (e.g., heat storing chamber) and a secondary chamber 106 (e.g., insulating chamber). The main chamber 104 and the secondary chamber 106 are located within the outer shell 102. In one implementation, the secondary chamber 106 is annular and surrounds the main chamber 104. Additionally, the secondary chamber 106 can have a curved or domed top portion and bottom portion which can allow for the insulating material to surround the main chamber 104 (e.g., so that the insulating material extends circumferentially around, above and below the main chamber 104), thereby providing more uniform and efficient insulation. The main chamber 104 can be filled with a heat storing material (e.g., rocks, pebbles, gravel). In one implementation, the rocks can be rounded and approximately 30-40 mm in size (e.g., diameter, width). The insulating material in the secondary chamber 106 can be sand or another suitable low cost insulating material (e.g., gravel). The insulating material located inside the secondary chamber 106 completely surrounds the main chamber 104 so heat does not freely escape the main chamber 104 when the heat storing material (e.g., rocks) is heated. Advantageously, the use of the insulating material between the outer shell 102 and the main chamber 104 allows the outer shell 102 to be made of steel (e.g., because the steel outer shell is thermally insulated by the secondary chamber 106 relative to the main chamber 104). In one implementation the insulating material located in the secondary chamber 106 can store thermal energy in addition to the heat storing material in the main chamber 104. The insulating material retains heat in the secondary chamber 106 which heats the main chamber 104. The energy from the heat from the main chamber 104 and the secondary chamber 106 can advantageously be used for thermal energy storage.

[0020] With continued reference to FIG. 4, the heat storing material in the main chamber 104 can be heated when heated air flows into the one or more pipes (e.g., first pipe 110A, second pipe HOB). The one or more pipes can be in fluid communication with the main chamber 104. The first pipe 110A can have an inlet 112A located externally to the outer shell 102. The first pipe 110A can extend through a portion (e.g., first portion) of the secondary chamber 106 and into the main chamber 104. The first pipe 110A can extend across an entire width or diameter of the main chamber 104. The openings 112B in the first pipe 110A can be located along the length (e.g., entire length) of the first pipe 110A that extends in the main chamber 104. The second pipe HOB can have an inlet 114A located externally to the outer shell 102. The second pipe HOB can extend through a portion (e.g., first portion) of the secondary chamber 106 and into the main chamber 104. The second pipe 110B can extend across an entire width or diameter of the main chamber 104. The openings 114B in the second pipe 110B can be located along the length (e.g., the entire length) of the second pipe 110B that extends in the main chamber 104. Advantageously, the openings 112B can allow heated air to flow into the main chamber 104 via the first pipe 110A and heat the heat storing material located in the main chamber 104, and the openings 114B can allow said heated air (e.g., air at a temperature higher than a temperature of the heat storing material) to flow out of the main chamber 104 via the second pipe HOB once it has passed through the heat storing material. Alternatively, having the openings 112B of the first pipe 110A and the openings 114B of the second pipe HOB in the main chamber 104 can allow warm air (e.g., ambient air or air at a temperature lower than a temperature of the heat storing material) to directly flow through the main chamber 104 and be heated by the heat storing material. The secondary chamber 106 can insulate the heat storing material and facilitate maintaining the temperature of the heat storing material (e.g., at an elevated temperature after charging the tank 100) by inhibiting (e.g., preventing) the heat within the main chamber 104 from escaping the tank 100 (e.g., through the walls of the main chamber 104). Advantageously, any effects of thermal expansion in the one or more pipes will not affect the flow of heated air in and out of the tank 100 since the pipes are vertically spaced apart.

[0021] When used in a thermal energy system in a charging mode, (e.g., to use electricity to store thermal energy in the tank 100) heated air (e.g., in a hot state, for example about 650°C) enters the thermal energy storage tank 100 through the first pipe 110A. The heated air then exits the first pipe 110A through the openings 112B and enters the main chamber 104 (e.g., at a top end 122 of the tank 100). Heat is transferred from the heated air to the heat storing material (e.g., rocks, such as a packed rock bed) in the main chamber 104. The heated air flows through the main chamber 104 from the top end 122, through the middle portion 124, and then enters the second pipe HOB via the openings 114B and exits the tank 100 (e.g., via the bottom end 126 of the tank 100) through the inlet 114A of the second pipe 110B. The heated air exits (e.g., exhausts from) the second pipe 110B at a lower temperature (e.g., warm or cooled air) than the temperature the heated air entered the first pipe 110A. Though not shown, the heated air that enters the first pipe 110A can come from a compressor which sends the heated air to the first pipe 110A, for example at a pressure of about 3 bar and a temperature of about 650°C.

[0022] When used in a thermal energy system in a discharging mode (e.g., to use thermal energy to generate electricity and, for example, transfer it to the electric grid) air flow enters the tank 100, for example through the inlet 114A of the second pipe 110B and passes through the openings 114B in the second pipe 110B into the main chamber 104 (e.g., at the bottom end 126 of the tank 100). Said air flows through the main chamber 104 from the bottom end 126, through the middle portion 124, and to the top end 122 and is heated by heat from the heat storing material (e.g., rocks, gravel, pebbles) located in the main chamber 104. The heated air flow then exits the thermal energy storage tank 100 by first passing through the openings 112B of the first pipe 110A and exiting the first pipe 110A at the inlet 112A at the top end 122 of the main chamber 104. In the discharging mode, the hottest portion of the tank 100 is the top end 122. In some implementations, the first pipe 110A is connected to a turbine and the heated air flow flows from the first pipe 110A to the turbine, which can generate electricity using the heated airflow (e.g., to rotate the turbine blades) and deliver said electricity to an energy grid.

[0023] In some implementations , the thermal energy storage tank 100 can be buried in the ground, thereby providing additional insulation to the main chamber 104 and the heat storing material therein. Additionally, the thermal energy storage tank 100 can be a hot thermal storage tank (e.g., operates at temperatures between approximately 393°C to 650°C) that operates under pressure (e.g., at 3 bar). The thermal energy storage tank 100 can be a warm thermal storage tank (e.g., operates at temperatures between approximately 57°C and 393°C). In some examples, the thermal energy storage tank 100 can have a height between 10 m to 20 m, such as about 11 m. Additionally, in some examples the thermal energy storage tank 100 can have a diameter of about 6 m. In some examples, the thermal energy storage tank 100 can have an outer diameter of about 30 m and have a height of about 20 m. The main chamber 104 can have a height of approximately 8 m and a diameter of approximately 4 m. The secondary chamber 106, which as noted above can be an annular chamber, can have an inner diameter of approximately 4 m and an outer diameter of approximately 6 m. Additionally, when the tank 100 is empty (e.g., does not have any insulating material or heat storing material), the thermal energy storage tank 100 can weigh approximately 70 tons. The one or more pipes can be designated DN300 - PN10. Furthermore, the one or more pipes can be vertically spaced apart by approximately 6 m. The distance between the bottom of the main chamber 104 and the ground portion G can be approximately 2 m.

Additional Embodiments

[0024] In embodiments of the present invention, a mooring system may be in accordance with any of the following clauses: [0025] Clause 1. A thermal energy storage tank, comprising: an outer shell; a main chamber positioned within the outer shell, wherein the main chamber is filled with a heat storing material; a secondary chamber surrounding the main chamber and positioned within the outer shell, wherein the secondary chamber is filled with an insulating material; and one or more pipes extending through the outer shell and into the main chamber and configured to receive a flow of air, the one or more pipes being in fluid communication with the main chamber.

[0026] Clause 2. The thermal energy storage tank of clause 1, wherein the heat storing material is a plurality of rocks.

[0027] Clause 3. The thermal energy storage tank of clause 1, wherein the one or more pipes have a plurality of openings, each opening having a diameter smaller than a size of the heat storing material.

[0028] Clause 4. The thermal energy storage tank of clause 1, wherein the insulating material is sand.

[0029] Clause 5. The thermal energy storage tank of clause 1, wherein the one or more pipes include a first pipe and a second pipe, wherein the first pipe is vertically spaced apart from the second pipe.

[0030] Clause 6. The thermal energy storage tank of clause 1, wherein the one or more pipes are configured to extend across the main chamber.

[0031] Clause 7. The thermal energy storage tank of clause 5, wherein the first pipe is configured to receive a flow of heated air and the second pipe is configured to exhaust a flow of cooled air, the heated air configured to heat the heat storing material in the main chamber.

[0032] Clause 8. The thermal energy storage tank of clause 5, wherein the second pipe is configured to receive a flow of ambient air and the first pipe is configured to exhaust a flow of heated air, the heat storing material configured to heat the ambient air flowing through the main chamber.

[0033] Clause 9. The thermal energy storage tank of clause 1, wherein the one or more pipes are configured to receive and exhaust a fluid.

[0034] Clause 10. The thermal energy storage tank of clause 9, wherein the fluid is a liquid. [0035] Clause 11. The thermal energy storage tank of clause 9, wherein the fluid is a gas.

[0036] Clause 12. The thermal energy storage tank of clause 1, wherein the insulating material is configured to store thermal energy.

[0037] Clause 13. The thermal energy storage tank of clause 1, further comprising a base portion configured to be fixed to a ground surface, the base portion including a plurality of supporting structures to inhibit the thermal energy storage tank from bending at a bottom portion.

[0038] Clause 14. The thermal energy storage tank of clause 1, further comprising a cap, the cap configured to cover an opening at a top end of the outer shell, the opening at the top end of the outer shell being configured to receive the insulating material therethrough.

[0039] Clause 15. The thermal energy storage tank of clause 1, wherein the one or more pipes are configured to receive a flow of heated air from a compressor.

[0040] Clause 16. The thermal energy storage tank of clause 1, wherein the one or more pipes are configured to deliver a flow of heated air to a turbine to generate electricity.

[0041] Clause 17. The thermal energy storage tank of clause 8, wherein a top end of the thermal energy storage tank is hotter than a bottom end.

[0042] Clause 18. The thermal energy storage tank of clause 8, wherein the second pipe is configured deliver the flow of ambient air to the main chamber through a plurality of openings along the second pipe, wherein the first pipe is configured to receive the heated air through a second plurality of openings positioned along the first pipe.

[0043] Clause 19. The thermal energy storage tank of clause 1, wherein the thermal energy storage tank is configured to be buried underneath a ground surface.

[0044] Clause 20. The thermal energy storage tank of clause 5, wherein the first pipe and the second pipe can be vertically spaced apart and laterally intersect.

[0045] While certain embodiments of the inventions have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the disclosure. Indeed, the novel methods and systems described herein may be embodied in a variety of other forms. Furthermore, various omissions, substitutions and changes in the systems and methods described herein may be made without departing from the spirit of the disclosure. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the disclosure. Accordingly, the scope of the present inventions is defined only by reference to the appended claims.

[0046] Features, materials, characteristics, or groups described in conjunction with a particular aspect, embodiment, or example are to be understood to be applicable to any other aspect, embodiment or example described in this section or elsewhere in this specification unless incompatible therewith. All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive. The protection is not restricted to the details of any foregoing embodiments. The protection extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

[0047] Furthermore, certain features that are described in this disclosure in the context of separate implementations can also be implemented in combination in a single implementation. Conversely, various features that are described in the context of a single implementation can also be implemented in multiple implementations separately or in any suitable subcombination. Moreover, although features may be described above as acting in certain combinations, one or more features from a claimed combination can, in some cases, be excised from the combination, and the combination may be claimed as a subcombination or variation of a subcombination.

[0048] Moreover, while operations may be depicted in the drawings or described in the specification in a particular order, such operations need not be performed in the particular order shown or in sequential order, or that all operations be performed, to achieve desirable results. Other operations that are not depicted or described can be incorporated in the example methods and processes. For example, one or more additional operations can be performed before, after, simultaneously, or between any of the described operations. Further, the operations may be rearranged or reordered in other implementations. Those skilled in the art will appreciate that in some embodiments, the actual steps taken in the processes illustrated and/or disclosed may differ from those shown in the figures. Depending on the embodiment, certain of the steps described above may be removed, others may be added. Furthermore, the features and attributes of the specific embodiments disclosed above may be combined in different ways to form additional embodiments, all of which fall within the scope of the present disclosure. Also, the separation of various system components in the implementations described above should not be understood as requiring such separation in all implementations, and it should be understood that the described components and systems can generally be integrated together in a single product or packaged into multiple products.

[0049] For purposes of this disclosure, certain aspects, advantages, and novel features are described herein. Not necessarily all such advantages may be achieved in accordance with any particular embodiment. Thus, for example, those skilled in the art will recognize that the disclosure may be embodied or carried out in a manner that achieves one advantage or a group of advantages as taught herein without necessarily achieving other advantages as may be taught or suggested herein.

[0050] Conditional language, such as “can,” “could,” “might,” or “may,” unless specifically stated otherwise, or otherwise understood within the context as used, is generally intended to convey that certain embodiments include, while other embodiments do not include, certain features, elements, and/or steps. Thus, such conditional language is not generally intended to imply that features, elements, and/or steps are in any way required for one or more embodiments or that one or more embodiments necessarily include logic for deciding, with or without user input or prompting, whether these features, elements, and/or steps are included or are to be performed in any particular embodiment.

[0051] Conjunctive language such as the phrase “at least one of X, Y, and Z,” unless specifically stated otherwise, is otherwise understood with the context as used in general to convey that an item, term, etc. may be either X, Y, or Z. Thus, such conjunctive language is not generally intended to imply that certain embodiments require the presence of at least one of X, at least one of Y, and at least one of Z.

[0052] Language of degree used herein, such as the terms “approximately,” “about,” “generally,” and “substantially” as used herein represent a value, amount, or characteristic close to the stated value, amount, or characteristic that still performs a desired function or achieves a desired result. For example, the terms “approximately”, “about”, “generally,” and “substantially” may refer to an amount that is within less than 10% of, within less than 5% of, within less than 1% of, within less than 0.1% of, and within less than 0.01% of the stated amount. As another example, in certain embodiments, the terms “generally parallel” and “substantially parallel” refer to a value, amount, or characteristic that departs from exactly parallel by less than or equal to 15 degrees, 10 degrees, 5 degrees, 3 degrees, 1 degree, or 0.1 degree.

[0053] The scope of the present disclosure is not intended to be limited by the specific disclosures of preferred embodiments in this section or elsewhere in this specification, and may be defined by claims as presented in this section or elsewhere in this specification or as presented in the future. The language of the claims is to be interpreted broadly based on the language employed in the claims and not limited to the examples described in the present specification or during the prosecution of the application, which examples are to be construed as non-exclusive.

[0054] Of course, the foregoing description is that of certain features, aspects and advantages of the present invention, to which various changes and modifications can be made without departing from the spirit and scope of the present invention. Moreover, the devices described herein need not feature all of the objects, advantages, features and aspects discussed above. Thus, for example, those of skill in the art will recognize that the invention can be embodied or carried out in a manner that achieves or optimizes one advantage or a group of advantages as taught herein without necessarily achieving other objects or advantages as may be taught or suggested herein. In addition, while a number of variations of the invention have been shown and described in detail, other modifications and methods of use, which are within the scope of this invention, will be readily apparent to those of skill in the art based upon this disclosure. It is contemplated that various combinations or subcombinations of these specific features and aspects of embodiments may be made and still fall within the scope of the invention. Accordingly, it should be understood that various features and aspects of the disclosed embodiments can be combined with or substituted for one another in order to form varying modes of the discussed devices.

Claims

WHAT IS CLAIMED IS:

1. A thermal energy storage tank, comprising: an outer shell; a main chamber positioned within the outer shell, wherein the main chamber is filled with a heat storing material; a secondary chamber surrounding the main chamber and positioned within the outer shell, wherein the secondary chamber is filled with an insulating material; and one or more pipes extending through the outer shell and into the main chamber and configured to receive a flow of air, the one or more pipes being in fluid communication with the main chamber.

2. The thermal energy storage tank of claim 1, wherein the heat storing material is a plurality of rocks.

3. The thermal energy storage tank of claim 1, wherein the one or more pipes have a plurality of openings, each opening having a diameter smaller than a size of the heat storing material.

4. The thermal energy storage tank of claim 1, wherein the insulating material is sand.

5. The thermal energy storage tank of claim 1, wherein the one or more pipes include a first pipe and a second pipe, wherein the first pipe is vertically spaced apart from the second pipe.

6. The thermal energy storage tank of claim 1, wherein the one or more pipes are configured to extend across the main chamber.

7. The thermal energy storage tank of claim 5, wherein the first pipe is configured to receive a flow of heated air and the second pipe is configured to exhaust a flow of cooled air, the heated air configured to heat the heat storing material in the main chamber.

8. The thermal energy storage tank of claim 5, wherein the second pipe is configured to receive a flow of ambient air and the first pipe is configured to exhaust a flow of heated air, the heat storing material configured to heat the ambient air flowing through the main chamber.

9. The thermal energy storage tank of claim 1, wherein the one or more pipes are configured to receive and exhaust a fluid.

10. The thermal energy storage tank of claim 9, wherein the fluid is a liquid.

11. The thermal energy storage tank of claim 9, wherein the fluid is a gas.

12. The thermal energy storage tank of claim 1 , wherein the insulating material is configured to store thermal energy.

13. The thermal energy storage tank of claim 1, further comprising a base portion configured to be fixed to a ground surface, the base portion including a plurality of supporting structures to inhibit the thermal energy storage tank from bending at a bottom portion.

14. The thermal energy storage tank of claim 1, further comprising a cap, the cap configured to cover an opening at a top end of the outer shell, the opening at the top end of the outer shell being configured to receive the insulating material therethrough.

15. The thermal energy storage tank of claim 1, wherein the one or more pipes are configured to receive a flow of heated air from a compressor.

16. The thermal energy storage tank of claim 1, wherein the one or more pipes are configured to deliver a flow of heated air to a turbine to generate electricity.

17. The thermal energy storage tank of claim 8, wherein a top end of the thermal energy storage tank is hotter than a bottom end.

18. The thermal energy storage tank of claim 8, wherein the second pipe is configured deliver the flow of ambient air to the main chamber through a plurality of openings along the second pipe, wherein the first pipe is configured to receive the heated air through a second plurality of openings positioned along the first pipe.

19. The thermal energy storage tank of claim 1, wherein the thermal energy storage tank is configured to be buried underneath a ground surface.

20. The thermal energy storage tank of claim 5, wherein the first pipe and the second pipe can be vertically spaced apart and laterally intersect.