JP5711755B2 - Thermal energy storage device for adiabatic compressed air energy storage system and corresponding method for forming the system - Google Patents

Description

  Embodiments of the present invention generally relate to a compressed air energy storage (CAES) system, and more specifically to a thermal energy storage (TES) system within an adiabatic CAES system.

  A CAES system allows for the storage of electrical energy without producing large amounts of emissions and / or without consuming large amounts of natural resources. A CAES system typically includes a compression system having one or more compressors. One or more compressors compress the intake air during the compression stage for storage in cavities, porous rock formations, depleted natural gas / oil fields, or other compressed air storage elements. The compressed air is then used to drive a turbine that generates electrical energy in an energy generation stage, which can then provide electrical energy to the power system. When power energy is used to power the compression system during the compression phase, the compression system often operates during off-peak hours of the power plant. The energy generation phase of CAES then typically operates during high power demand times. Alternatively, energy from renewable resources, such as energy from a wind turbine or solar panel array, compresses the air to power the compression system during the compression phase and compresses the air into a compressed air storage location (cavity Etc.) can be used. In this way, the compression system can be operated during times other than off-peak hours, and the existing power energy can be preserved.

  One type of CAES system is known as a non-insulated CAES system. In a non-adiabatic CAES system, the heat generated by the compression system typically disappears into the surrounding environment. That is, the heat of compression may disappear around the interior of the intercooler, and the heat left when entering the cavity or other compressed air storage element is further mixed during storage as the compressed air is mixed with the air of the cavity. When cooled to ambient temperature, it drops. Thus, when compressed air stored in a cavity or compressed air storage element is used to drive one or more turbines to generate electrical energy, the compressed air typically enters the turbine. Reheated before. This reheating step is typically performed using a natural gas soot combustor and a recuperated heat exchanger located between the compressed air storage element and one or more turbines. Because of this reheating step, the overall efficiency of the non-adiabatic CAES system is reduced, and the use of natural gas injected into the combustor leads to carbon emissions and consumption of natural resources.

  An adiabatic CAES or ACAES system can improve system efficiency by capturing and storing compression heat for later use. In such a system, one or more thermal energy storage (TES) units are placed between the compressor and the cavity. Typically, a TES unit includes therein a medium for heat storage, such as concrete, stone, fluid (such as oil), molten salt, or phase change material. Hot air from the compression stage passes through the TES unit, thereby transferring its heat of compression to the media during the process. Thus, unlike non-adiabatic CAES systems, ACAES systems do not lose all of the heat generated by the compression system, but instead store some heat in a TES unit or multiple TES units. The compressed air then enters the cavity at or near ambient temperature.

  When drawing compressed air stored in a cavity or other compressed air storage unit to drive one or more turbines to generate electrical energy, the compressed air returns through the TES unit, Thereby, the compressed air is reheated before entering the turbine or turbines. Thus, the ACAES system does not require additional natural gas to reheat the compressed air present in the cavities or other compressed air storage elements. Thus, the ACAES system provides improved efficiency over non-adiabatic CAES systems, has low carbon emissions (if any), and little or no natural resource consumption.

  TES units built to effectively store heat generated during the compression cycle of the compression system are built to withstand high thermal fluctuations and high pressures associated with ACAES systems. For example, the temperature of the compressed air present in the compression system can vary from 250 ° C. to 750 ° C., but the temperature of the compressed air entering the TES unit from the cavity is close to the outside air temperature. Similarly, the TES unit is designed to withstand a pressure of 65 to 85 bar. In order to withstand such high temperatures and pressures, current proposals for TES units include the construction of large concrete cylinders filled with a medium for heat storage. Due to the large diameter of the cylinders, these TES units are formed to have thick, pre-stressed reinforced concrete walls, by which the TES units are formed by internal pressure, Can withstand high tensile force. However, the construction of such thick concrete walls leads to significant engineering problems and high costs, thereby reducing the feasibility of implementing ACAES systems as opposed to inefficient non-insulated CAES systems. Furthermore, high operating temperatures and temperature cycles lead to destructive thermal stresses on the concrete walls, which are amplified as the concrete walls become thicker.

  Therefore, it is desirable to design an apparatus and method that overcomes the above-mentioned drawbacks associated with TES unit construction.

U.S. Pat. No. 4,147,204

  Aspects of the invention provide a system having at least one TES unit configured to withstand high temperatures and pressures, and a method for a TES system. At least one TES unit is constructed and configured such that its wall has a minimum thickness.

  According to one aspect of the present invention, a thermal energy storage system is disclosed, the thermal energy storage system comprising a plurality of pressure vessels disposed in close proximity to each other, each of these pressure vessels comprising an outer surface; A wall having a respective wall thickness spaced from the outer surface and an inner surface surrounding the inner volume of the pressure vessel. The internal volume includes a first end in fluid communication with the one or more compressors and the one or more turbines, one or more additional compressors, one or more additional turbines, and at least A second end in fluid communication with at least one of the compressed air storage elements. The thermal energy storage system further comprises a heat storage medium disposed within each internal volume of the plurality of pressure vessels.

  In accordance with another aspect of the present invention, a method of forming a thermal energy storage system is disclosed, the method comprising a wall constructed to have a predetermined height and thickness, the inner surface of the wall Forming a first pressure vessel defining an internal volume therein and having a wall of a predetermined height and thickness, the inner surface of the wall defining the internal volume therein. Forming a second pressure vessel. The method includes disposing a porous heat storage medium within the internal volume of each of the first and second pressure vessels, and disposing the first and second pressure vessels in close proximity to each other. Further included. Further, the method can include each of the first and second pressure vessels such that each of the first and second pressure vessels is in fluid communication with the one or more compressors and the one or more turbines. Connecting the first end to one or more compressors and one or more turbines, and each of the first and second pressure vessels includes one or more additional compressors, 1 One or more second ends of each of the first and second pressure vessels are in fluid communication with one or more additional turbines and at least one of the one or more compressed air storage elements. And connecting to at least one of one or more additional compressors, one or more additional turbines, and one or more compressed air storage elements.

  In accordance with yet another aspect of the present invention, a thermal energy storage device is disclosed, the thermal energy storage device defining a first concrete cylindrical wall defining a first internal volume and a second internal volume. A second concrete cylindrical wall, wherein the second concrete cylindrical wall has a first internal volume of the first concrete cylindrical wall such that the first concrete cylindrical wall and the second concrete cylindrical wall are coaxial. Placed inside. The thermal energy storage device further comprises a porous thermal matrix material disposed within the first internal volume of the first concrete cylindrical wall and within the second internal volume of the second concrete cylindrical wall.

  Various other features and advantages will be made apparent from the following detailed description and the drawings.

  The drawings illustrate preferred embodiments presently contemplated for carrying out the invention.

1 is a schematic configuration diagram of an ACAES system according to an embodiment of the present invention. 1 is a cross-sectional view of a TES system according to an embodiment of the present invention. FIG. 6 is a cross-sectional view of a TES system according to another embodiment of the present invention. FIG. 4 is a plan view of a TES system according to the embodiment of FIG. 3. FIG. 6 is a cross-sectional view of a TES system according to another embodiment of the present invention. FIG. 3 is a cross-sectional view of a TES system positioned in a hollow shaft according to another embodiment of the present invention.

  In accordance with an embodiment of the present invention, a system is provided comprising at least one TES unit configured to withstand high pressure and temperature fluctuations while maintaining a minimum wall thickness.

  First, referring to FIG. 1, a schematic block diagram of the main elements of an ACAES system is shown. The ACAES system 100 includes an electric motor 102 that couples to a low pressure compressor 104. The electric motor 102 can be supplied with electricity through conventional means, i.e., the power system, during off-peak power supply time. Alternatively, the electric motor 102 can be powered by electricity supplied through windmills, solar cells, or other renewable resources. The electric motor 102 provides power to the low pressure compressor 104 such that the low pressure compressor 104 compresses the intake air 106. The compressed air 108 from the low pressure compressor 104 is then supplied to the high pressure compressor 112 so that the air is further compressed. Similar to the low pressure compressor 104, the high pressure compressor 112 is powered by an electric motor 110. The electric motor 110 can also be powered by a power system or by renewable resources such as windmills and solar cells. Although the ACAES system 100 is shown as using two compressors in a “compression system”, it should be understood that more or fewer compressors may be used.

  As the air passes through the low pressure compressor 104 and the high pressure compressor 112, respectively, the air is compressed to a level of 65-85 bar and subsequently heated to a temperature of 650 ° C. This compressed heated air 114 then enters at least one thermal energy storage (TES) unit 116. The at least one TES unit 116 typically includes a porous heat storage medium disposed therein, which is released by the air 114 as the air 114 passes through the at least one TES unit 116. Can store a sufficient amount of heat. The porous heat storage medium can be a variety of solid materials such as natural stone (such as cracked rock and / or gravel), ceramic, concrete, cast iron, or a composite of ceramic and salt. Alternatively, the porous heat storage medium can be a liquid material such as a composite of nitrate and mineral oil. However, the advantage of using natural heat storage media materials such as cracked rocks and / or gravel is that if such natural materials are readily available, material costs can be significantly reduced and manufacturing / transport energy can be saved. It is. When using natural stone as the porous heat storage medium, the cracked rock and / or gravel should be sized appropriately to have a high surface area to volume ratio and temperature resistance.

  After the heated air 114 has passed through the at least one TES unit 116, the compressed air 118 exits the at least one TES unit 116 at a reduced temperature, causing the compressed air 118 to enter the cavity 122 or other compressed air storage element. Can be stored. However, before entering the cavity 122, the compressed air 118 may need to be further cooled by an optional intercooler 120 such that the compressed air 118 enters the cavity 122, for example at a maximum temperature of about 50 ° C. There is. The cavity 122 can compress air to a level of about 60-80 bar and stores it for a long time without significant compression loss.

  Still referring to FIG. 1, the compressed air 124 can be released from the cavity 122 when it is desired to use stored air for power generation. Compressed air 124 exits cavity 122 and reenters at least one TES unit 116 at a temperature of about 20-50 ° C. As the compressed air passes through the porous thermal storage medium of at least one TES unit 116, it is reheated to a temperature of 600 ° C., which is close to the temperature of the heated air 114 previously released from the high pressure compressor 112. This reheated compressed air 126, compressed to a level of about 55-75 bar at this stage, then enters turbine 128, which is powered by reheated compressed air 126. More than one turbine 128 may be used, forming an “expansion system”. Unlike the non-adiabatic CAES system, the compressed air 126 is reheated in at least one TES unit 116, so there is no need for additional heat regeneration or gas combustion in the steam turbine to reheat the compressed air. When the steam turbine 128 operates, the exhaust 130 is then released and the turbine 128 powers the generator 132. The electrical energy generated by the generator 132 can then be supplied to the power system for consumption. As will be readily appreciated, the ACAES system 100 represents a power generation method that, if not omitted, can significantly reduce natural resource consumption and / or carbon emissions in the production of electrical energy.

  Alternatively, what is known as a multi-stage ACAES system, only one TES unit is fluidly connected to a cavity or other compressed air storage element, while fluidly connected to the compression and / or expansion system and the compressed air storage element. Two or more TES units 116 can be used such that one or more intermediate TES units are arranged between the TES units connected to the. These intermediate TES units are not fluidly connected to one or more compressors and one or more turbines at one end and to a compressed air storage element at the other end, but at each end thereof. In fluid connection to one or more compressors and one or more turbines.

  As described above with respect to FIG. 1, at least one TES unit 116 may be exposed to high pressure (65-85 bar) and temperature (up to 650 ° C.) during operation of the ACAES system 100. As a result, at least one TES unit 116 should be constructed to withstand such high pressure and temperature levels. Referring to FIG. 2, a TES system 216 according to one embodiment of the present invention is shown. It is understood that the TES system 216 can be used as at least one TES unit 116 shown in FIG. 1, whereby the TES system 216 can withstand the high pressures and temperatures associated with the operation of the ACAES system. I want.

  FIG. 2 shows a cross-sectional view of the TES system 216. The TES system 216 includes two separate coaxial cylindrical pressure vessels 218, 220. The pressure vessel 218 includes a wall 222 having a predetermined length and diameter, and the length of the wall 222 can range from 10 to 30 m, but the diameter can range from 3 to 6 m. There is sex. However, the pressure vessel 218 is not limited to such a length and diameter range, and can be larger or smaller in both length and diameter. On the other hand, the pressure vessel 220 includes a wall 224 having a predetermined length and diameter, and the length of the wall 224 may be in the range of 10-30 m, but the diameter is in the range of 5-12 m. There is a possibility. However, like the pressure vessel 218, the length and diameter of the pressure vessel 220 are not limited to the above ranges. The pressure vessels 218, 220 are typically formed using reinforced concrete, but can be formed using any suitable material, including steel. Furthermore, the pressure vessels 218 and 220 are not limited to a cylindrical shape, and can be formed to have any appropriate shape.

  As clearly shown in FIG. 2, the pressure vessel 218 is disposed within the boundary of the internal volume of the pressure vessel 220. The internal volume of the pressure vessel 218 includes a porous heat storage medium 226 therein, while the internal volume of the pressure vessel 220 includes a porous heat storage medium 228 therein. The porous heat storage media 226, 228 can be composed of the same heat storage medium, or alternatively can be composed of various heat storage materials.

  Similar to that described above with respect to FIG. 1, the TES system 216 is configured to receive compressed air from at least one compressor so that the compressed air is at the first end 230 at each end. Enter the pressure vessels 218, 220 and exit the respective pressure vessels 218, 220 at the second end 232 to allow compressed air to be stored in the compressed air storage unit, or alternatively (multistage ACAES In the case of a system) it is possible to supply additional compressors and / or turbines. Heat from compressed air received from at least one compressor can be stored in respective porous heat storage media 226,228. When the stored compressed air is used for power generation, the stored compressed air re-enters the respective pressure vessels 218, 220 at the second end 232, and the compressed air is in the respective porous heat storage medium 226. When it passes through 228, it is reheated. The reheated air then exits each pressure vessel 218, 220 at the first end 230 and is supplied to one or more steam turbines to power the generator.

  Unlike conventional TES systems having a single pressure vessel, the TES system 216 allows the pressure vessels 218, 220 to receive compressed air, each having varying pressure levels. That is, pressure vessel 218 can be configured to receive high pressure compressed air input from both one or more compressors and compressed air storage units, while pressure vessel 220 can be configured to receive one or more compressions. And low pressure compressed air input from the compressor and compressed air storage unit. In one embodiment, pressure vessel 218 is configured to receive (and withstand) a pressure of 40-80 bar, while pressure vessel 220 is configured to receive (and withstand) a pressure of 5-20 bar. Composed. Since the pressure vessel 218 has a smaller diameter (and hence lower tensile force) than the pressure vessel 220, the pressure vessel 218 is higher even if the thickness of the wall 222 is less than the thickness of the wall 224. Can withstand pressure. Further, since the pressure vessel 218 is disposed within the internal volume of the pressure vessel 220, the low pressure compressed air that passes through the porous heat storage medium 228 is compressed between the compressed air that passes through the pressure vessel 218 and the outside of the pressure vessel 218. It works to reduce the differential pressure with air. The wall of a typical single pressure vessel is surrounded by ambient air pressure, but since the pressure vessel 218 is surrounded by low pressure compressed air passing through the pressure vessel 220, the tensile force in the wall 222 is reduced, and thus the wall 222 can be constructed to have a significantly reduced thickness when compared to pressure vessels used in conventional TES systems. Further, since the pressure vessel 220 is exposed to low pressure compressed air, the thickness of the wall 224 can also be significantly smaller than the thickness of a conventional TES pressure vessel.

  In addition, the temperature difference between the compressed air passing through the pressure vessel 218 and the compressed air passing through the pressure vessel 220 results in a temperature difference between the compressed air passing through the conventional TES unit and the ambient outside air. The heat loss from the pressure vessel 218 is also reduced when compared to conventional TES systems. Thus, even though the wall 222 is thinner than a conventional pressure vessel wall, heat loss is reduced due to the coaxial integral configuration of the pressure vessels 218, 220 of the TES system 216.

  As shown in FIG. 2, the TES system 216 is formed from a combination of a pressure vessel 218 and a pressure vessel 220 so that each pressure vessel 218, 220 is generally high, even at a reduced wall thickness. It can be constructed to withstand pressure and temperature. Thus, the cost and complexity of building and transporting the TES system 216 is significantly less than that of a typical TES system because the advantage of a smaller pressure vessel is added, and thus the overall footprint of the TES system is small.

  Referring now to FIG. 3, another embodiment according to the present invention is shown. FIG. 3 schematically shows a TES system 316 comprising three separate pressure vessels 318, 320, 322 arranged in fluid parallel. The first pressure vessel 318 has a wall 324 surrounding the heat storage medium 334, the second pressure vessel 320 has a wall 326 surrounding the heat storage medium 336, and the third pressure vessel 322 is a heat storage There is a wall 328 surrounding the media 338. Although each pressure vessel 318, 320, 322 can be similarly constructed, it is envisioned that embodiments of the present invention are not limited as such.

  The pressure vessels 318, 320, 322 are arranged in close proximity so that compressed air from at least one compressor can enter each pressure vessel at the first end 330 of the pressure vessel 318, 320, 322. Is done. The compressed air passes through the pressure vessels 318, 320, 322, whereby heat from the compressed air is captured and stored in the respective heat storage media 334, 336, 338. The compressed air then exits the respective pressure vessel at the second end 332 of the pressure vessel 318, 320, 322, and the compressed air is similar to that described above with respect to FIG. It is stored in an air storage device or alternatively supplied to an additional compressor and / or turbine. When the stored compressed air is used for power generation, the stored compressed air reenters the respective pressure vessels 318, 320, 322 at the second end 332, and the compressed air is stored in the respective porous heat storage. As it passes through the media 334, 336, 338, it is reheated. The reheated air then exits the respective pressure vessels 318, 320, 322 at the first end 330 and is supplied to one or more steam turbines to power the generator.

  Although FIG. 3 shows three separate pressure vessels 318, 320, 322, the present invention is not limited to a specific number of pressure vessels, and may comprise any number of closely spaced or filled pressure vessels. Can do. As shown in FIG. 4, the pressure vessels 318, 320, 322 are arranged such that their respective walls 324, 326, 328 are in close proximity to each other (eg, in centimeters, at most 1 meter apart). Are preferably arranged in a triangular array. When there are more or fewer pressure vessels, other geometrical arrangements such as a hexagonal arrangement can be used to ensure that the pressure vessels are placed in close proximity. Using such an arrangement, the thermal insulation layer 340 can only be placed around the periphery of the pressure vessels 318, 320, 322 that are filled in close proximity, and thus, within the respective walls 324, 326, 328, Heat loss, thermal stress, and / or thermal gradient can be minimized. In this way, the design and construction of the TES system 316 is simplified because separate thermal insulation layers disposed around each of the pressure vessels 318, 320, 322 are avoided.

  By using multiple, closely packed pressure vessels, the TES system 316 is capable of high temperature and pressure without the need for a single TES unit that has both large diameter and large wall thickness requirements. Can withstand effectively. Thus, the TES system 316 reduces the system size and weight, thereby effectively removing thermal energy into the ACAES system that eliminates many of the building and transportation problems that may be associated with conventional TES systems. Allows storage.

  FIG. 5 shows another embodiment according to the present invention. The TES unit 416 includes a pressure vessel having a cylindrical wall 418 that includes a heat storage medium 420 disposed therein. The TES unit 416 operates similarly to the TES systems 216 and 316 described above with respect to FIGS. 2 and 3 so that compressed air from at least one compressor is directed to the TES unit 416 at the first end 422. enter. The compressed air passes through the heat storage medium 420 and can take heat from the compressed air into the TES unit 416 and store it. The compressed air then exits the TES unit 416 at the second end 424 and the compressed air is stored in a cavity or other compressed air storage unit for later use in power generation.

  The cylindrical wall 418 is preferably constructed to have a high length-to-diameter ratio using a strong material (such as steel) having a thin thickness. Using such a small diameter, the thickness of the cylindrical wall 418 can be made smaller than the reinforced concrete wall of a conventional TES unit, but effectively captures the heat required for use in an ACAES system, To store heat, the increased length cylindrical wall 418 can again have a sufficient amount of heat storage medium 420 disposed therein. Further, FIG. 5 shows only a single TES unit 416, but in a manner similar to that shown and described with respect to FIGS. 3-4, a plurality of such TES units are paralleled to form a close-packed group of TES units. It is envisaged that it can be arranged in Thus, while increased compressed air volume can be handled by multiple TES units 416, the reduced system size and weight of each individual TES unit 416 can be associated with many Further eliminate construction and transportation problems.

  Referring now to FIG. 6, another embodiment according to the present invention is shown. While the conventional TES unit is constructed to be a ground heat storage unit that is fluidly connected to a cavity or other compressed air storage unit via a conduit / pipe network, the TES system 516 shown in FIG. A TES unit 518 configured to be disposed below the ground surface is provided. Specifically, the TES unit 518 includes a wall 520 that includes a porous heat storage medium 522 therein. The operation of the TES unit 518 is similar to the operation of the TES unit described above with respect to FIGS. 2-5, and therefore details of the operation will not be repeated. Although TES unit 518 is shown as a single unit, it should be understood that TES unit 518 can be configured in a variety of ways, including the configurations described above with respect to FIGS.

  The TES unit 518 is incorporated into the shaft 524 of the cavity 526 so that it surrounds the wall 520 of the TES unit 518 within the rock / soil 528 such that the TES unit 518 is positioned below the ground surface 530. Compressed air from at least one compressor enters the TES unit 518 at the first end 532 and exits the TES unit 518 at the second end 534. The compressed air is then stored in the cavity 526 for final power generation as described above.

  Since the TES unit 518 of the TES system 516 is located below the ground surface 530, the wall 520 is surrounded by rock / soil 528 and the thickness of the wall 520 (and any insulation surrounding the wall 520 (not shown)). ) Can be greatly reduced. The rock / soil 528 provides a natural reaction to the high tensile forces in the wall 520 caused by the high pressure inside, and the rock / soil 528 also provides natural insulation that reduces heat loss in the system. In addition, the incorporation of the TES unit 518 into the shaft 524 of the cavity 526 can reduce the ground footprint of the ACAES plant. Furthermore, the TES system 516 overcomes the manufacturing and transportation issues associated with some conventional TES systems, thereby reducing costs and simplifying the implementation of TES units within the ACAES system.

  Thus, according to one embodiment of the present invention, a thermal energy storage system is disclosed, the thermal energy storage system comprising a plurality of pressure vessels arranged in close proximity to each other, each of these pressure vessels A wall having a surface and an inner surface spaced from the outer surface by a respective wall thickness and surrounding the inner volume of the pressure vessel. The internal volume includes a first end in fluid communication with the one or more compressors and the one or more turbines, one or more additional compressors, one or more additional turbines, and at least A second end in fluid communication with at least one of the compressed air storage elements. The thermal energy storage system further comprises a heat storage medium disposed within each internal volume of the plurality of pressure vessels.

  In accordance with another embodiment of the present invention, a method of forming a thermal energy storage system is disclosed, the method comprising a wall constructed to have a predetermined height and thickness, the interior of the wall Constructed to form a first pressure vessel with a surface defining an interior volume therein and having a wall of a predetermined height and thickness, the inner surface of the wall defining the interior volume therein Forming a second pressure vessel. The method includes disposing a porous heat storage medium within the internal volume of each of the first and second pressure vessels, and disposing the first and second pressure vessels in close proximity to each other. Further included. Further, the method can include each of the first and second pressure vessels such that each of the first and second pressure vessels is in fluid communication with the one or more compressors and the one or more turbines. Connecting the first end to one or more compressors and one or more turbines, and each of the first and second pressure vessels includes one or more additional compressors, 1 One or more second ends of each of the first and second pressure vessels are in fluid communication with one or more additional turbines and at least one of the one or more compressed air storage elements. And connecting to at least one of one or more additional compressors, one or more additional turbines, and one or more compressed air storage elements.

  In accordance with yet another embodiment of the present invention, a thermal energy storage device is disclosed, the thermal energy storage device defining a first concrete cylindrical wall defining a first internal volume and a second internal volume. A second concrete cylindrical wall, wherein the second concrete cylindrical wall has a first interior of the first concrete cylindrical wall such that the first concrete cylindrical wall and the second concrete cylindrical wall are coaxial. Located in the volume. The thermal energy storage device further comprises a porous thermal matrix material disposed within the first internal volume of the first concrete cylindrical wall and within the second internal volume of the second concrete cylindrical wall.

  The description provided herein is intended to enable the person of ordinary skill in the art to disclose the invention and includes making and using any device or system and implementing any embodied method. An example including the best mode is used so that the invention can be practiced. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples include structural elements that do not differ from the language of the claims, or that include equivalent structural elements that do not substantially differ from the language of the claims. It shall be within the range.

DESCRIPTION OF SYMBOLS 100 ACAES system 102 Electric motor 104 Low pressure compressor 106 Intake 108 Compressed air 110 Electric motor 112 High pressure compressor 114 Compressed heating air 116 TES unit 118 Compressed air 120 Intercooler 122 Cavity 124 Compressed air 126 Reheated compressed air 128 Steam turbine 130 Exhaust 132 Generator 216 TES system 218 Pressure vessel 220 Pressure vessel 222 Wall 224 Wall 226 Porous heat storage medium 228 Porous heat storage medium 230 First end 232 Second end 316 TES system 318 First pressure vessel 320 Second pressure vessel 322 Third pressure vessel 324 Wall 326 Wall 328 Wall 330 First end 332 Second end 334 Heat storage medium 336 Heat storage medium 338 Heat storage medium 340 Thermal insulation layer 416 TES Knit 418 Cylindrical wall 420 Heat storage medium 422 First end 424 Second end 516 TES system 518 TES unit 520 Wall 522 Porous heat storage medium 524 Shaft 526 Cavity 528 Rock / soil 530 Ground surface 532 First end Part 534 second end

Claims (13)

A thermal energy storage system comprising a plurality of pressure vessels arranged in close proximity to each other,
Each of the pressure vessels is
An outer surface;
An inner surface spaced from the outer surface by a respective wall thickness and enclosing the internal volume of the pressure vessel;
A wall comprising
The internal volume is
A first end in fluid communication with the one or more compressors and the one or more turbines;
A second end in fluid communication with at least one of the one or more additional compressors, the one or more additional turbines, and the at least one compressed air storage element;
Have
A heat storage medium disposed within the internal volume of each of the plurality of pressure vessels;
The plurality of pressure vessels include a first pressure vessel and a second pressure vessel having a height equal to that of the first pressure vessel, and the first pressure vessel is the inside of the second pressure vessel. Placed in the volume,
Thermal energy storage system.   The wall of the first pressure vessel has a first wall thickness and a first diameter, and the wall of the second pressure vessel includes a second wall thickness and a second diameter. The thermal energy storage system of claim 1, wherein the first diameter is smaller than the second diameter.   The thermal energy storage system according to claim 1 or 2, wherein the first pressure vessel is configured to withstand a higher pressure level than the second pressure vessel.   The thermal energy storage system according to any one of claims 1 to 3, wherein each of the walls of the plurality of pressure vessels is formed of either steel or concrete.   5. The thermal energy storage system according to claim 1, wherein the heat storage medium is a porous heat storage medium disposed in the internal volume of each of the plurality of pressure vessels.   The thermal energy storage system of claim 5, wherein the porous heat storage medium comprises at least one natural stone material.   The plurality of pressure vessels are disposed within a hollow shaft, the hollow shaft being in fluid communication with the at least one compressed air storage element and disposed below the ground surface. Thermal energy storage system.   The thermal energy storage system according to any one of claims 1 to 7, wherein each of the plurality of pressure vessels has a cylindrical shape. A method of forming a thermal energy storage system comprising:
Forming a first pressure vessel having a wall constructed to have a predetermined height and thickness, the inner surface of the wall defining an internal volume therein;
Forming a second pressure vessel constructed to have the same height as the first pressure vessel and a wall thicker than the first pressure vessel, the inner surface of the wall defining an internal volume therein; When,
Disposing a porous heat storage medium within the internal volume of each of the first and second pressure vessels;
Disposing the first pressure vessel within the internal volume of the second pressure vessel;
A first end of each of the first and second pressure vessels such that each of the first and second pressure vessels is in fluid communication with one or more compressors and one or more turbines. Connecting a section to the one or more compressors and the one or more turbines;
Each of the first and second pressure vessels is in fluid communication with at least one of one or more additional compressors, one or more additional turbines, and one or more compressed air storage elements. A second end of each of the first and second pressure vessels, the one or more additional compressors, the one or more additional turbines, and the one or more compressions Connecting to at least one of the air storage elements;
Including a method. A first concrete cylindrical wall defining a first internal volume;
A second internal volume is defined and disposed within the first internal volume of the first concrete cylindrical wall such that the first concrete cylindrical wall and the second concrete cylindrical wall are coaxial. A second concrete cylindrical wall;
A porous thermal matrix material disposed within the first internal volume of the first concrete cylindrical wall and within the second internal volume of the second concrete cylindrical wall;
Both the first concrete cylindrical wall and the second concrete cylindrical wall have a first end and a second end, the first end comprising one or more compressors and In fluid communication with one or more turbines, the second end is at least one of one or more compressed air storage elements, one or more additional compressors, and one or more additional turbines. In fluid communication with one
Thermal energy storage device.   The thermal energy storage device according to claim 10, wherein a diameter of the second concrete cylindrical wall is smaller than a diameter of the first concrete cylindrical wall.   The first end of the second concrete cylindrical wall receives a pressure input from the one or more compressors that is higher than the first end of the first concrete cylindrical wall; The second end of the second concrete cylindrical wall receives a pressure input from the at least one compressed air storage element that is higher than the second end of the first concrete cylindrical wall; The thermal energy storage device according to claim 10 or 11. 13. A thermal energy storage device according to any of claims 10 to 12, wherein the porous thermal matrix material comprises at least one natural stone material.

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