Compressed air energy storage system

Abstract

The invention discloses a compressed air energy storage system which comprises an air storage component, a compressed air energy storage component, a compressed air energy storage component and a compressed air energy storage component. The compressed air assembly is arranged on the first connecting pipeline and comprises a plurality of compressors and a refrigerating and heating heat exchanger, and the compressors comprise a low-pressure compressor, a medium-pressure compressor and a high-pressure compressor which are sequentially connected in series from the air inlet; the expansion acting assembly is arranged on the second connecting pipeline and comprises a plurality of air turbines and a heat supply heat exchanger; the heat exchange assembly is connected with the refrigerating and heating heat exchanger and the heat supply heat exchanger; wherein the high-pressure compressor close to the air storage component comprises a reciprocating compressor, and the gas displacement of the reciprocating compressor is controlled by adjusting the opening and closing time of an air inlet valve of the reciprocating compressor through a stepless air volume adjusting actuator of the reciprocating compressor. The problem that a compressed air energy storage system in the prior art cannot achieve reliable, economical and efficient variable backpressure compression energy storage is solved.

Description

Technical Field

[0001] The present application relates to the technical field of compressed air energy storage, and in particular to a compressed air energy storage system. Background Art

[0002] Compressed air energy storage (CAES) is a key method for large-scale, long-duration energy storage. With the rapid growth of installed photovoltaic and wind power capacity, the grid's demand for large-scale, long-duration energy storage (especially CAES) exceeding one million megawatts is also rapidly increasing. Reliability, cost-effectiveness, and efficiency are key requirements for CAES systems.

[0003] During the standard atmospheric compression process of the gas stored in the air storage component, the pressure in the air storage component gradually increases from the minimum storage pressure to the maximum storage pressure, at which point the standard atmospheric compression process ends. During this process, the compressor outlet pressure equals the pressure in the air storage component, so the compressor is in a state of variable backpressure during operation.

[0004] Currently, a multi-stage compression system is commonly used to transform the pressure of gas storage components. This system consists of n stages connected in series, with the first n-1 stages representing stable conditions, and the final stage (n) representing variable conditions. This variable-condition compression process primarily relies on variable-frequency motors to vary the compressor speed. This requires additional variable-frequency equipment, resulting in significant operating losses and making it difficult to achieve high compression and system efficiency.

[0005] Therefore, how to achieve reliable, economical and efficient variable back pressure compression energy storage is one of the important issues that need to be solved in compressed air energy storage systems. Summary of the Invention

[0006] The main purpose of this application is to provide a compressed air energy storage system to solve the problem that the compressed air energy storage system in the prior art cannot achieve reliable, economical and efficient variable back pressure compressed energy storage.

[0007] To achieve the above objectives, according to one aspect of the present application, a compressed air energy storage system is provided, comprising: an air storage component, a first connecting pipeline, and a second connecting pipeline, wherein the air storage inlet of the air storage component is connected to the first connecting pipeline, and the air storage outlet of the air storage component is connected to the second connecting pipeline; a compressed air assembly, wherein the compressed air assembly is disposed on the first connecting pipeline and includes multiple compressors and a refrigeration and heat exchanger, wherein the multiple compressors include a low-pressure compressor, a medium-pressure compressor, and a high-pressure compressor connected in series from the air inlet; an expansion work assembly, wherein the expansion work assembly is disposed on the second connecting pipeline and includes multiple air turbines and a heat supply heat exchanger; and a heat exchange assembly, wherein the heat exchange assembly is connected to the refrigeration and heat supply heat exchanger and the heat supply heat exchanger to provide heat extracted from cooling the compressed air in the first connecting pipeline to the compressed air in the second connecting pipeline; wherein the high-pressure compressor located near the air storage component includes a reciprocating compressor, wherein the exhaust volume of the reciprocating compressor is controlled by adjusting the opening and closing time of the reciprocating compressor's intake valve by a stepless air volume adjustment actuator of the reciprocating compressor.

[0008] Furthermore, the pressure of the air at the gas outlet of the low-pressure compressor is greater than the pressure of the air at the gas inlet of the low-pressure compressor; the low-pressure compressor includes: an integrally geared centrifugal compressor; or multiple integrally geared centrifugal compressors, and the multiple integrally geared centrifugal compressors are arranged in series or in parallel with each other.

[0009] Furthermore, the pressure of the air at the gas inlet of the high-pressure compressor is greater than the pressure of the air at the gas inlet of the medium-pressure compressor, and the pressure of the air at the gas outlet of the high-pressure compressor is greater than the pressure of the air at the gas inlet of the high-pressure compressor; the high-pressure compressor includes: a reciprocating compressor; or multiple reciprocating compressors, and the multiple reciprocating compressors are arranged in series or in parallel.

[0010] Furthermore, the pressure of the air at the gas inlet of the medium-pressure compressor is greater than the pressure of the air at the gas inlet of the low-pressure compressor, and the pressure of the air at the gas outlet of the medium-pressure compressor is greater than the pressure of the air at the gas inlet of the medium-pressure compressor; the medium-pressure compressor includes: an integrally geared centrifugal compressor; or multiple integrally geared centrifugal compressors, and the multiple integrally geared centrifugal compressors are arranged in series or in parallel.

[0011] Furthermore, the expansion work component includes: a generator, and the air turbine is mechanically driven to the generator.

[0012] Furthermore, the expansion work component includes: a high-pressure air turbine, the gas inlet of the high-pressure air turbine is connected to the gas storage outlet; a low-pressure air turbine, the gas inlet of the low-pressure air turbine is connected to the gas outlet of the high-pressure air turbine; wherein, the high-pressure air turbine and the low-pressure air turbine are mechanically driven and connected, and the low-pressure air turbine and the generator are mechanically driven and connected.

[0013] Furthermore, the heat exchange assembly includes: a heat storage component and a cold storage component; a refrigeration pipeline, the outlet of the refrigeration pipeline is connected to the inlet of the heat storage component, and the inlet of the refrigeration pipeline is connected to the outlet of the cold storage component; a heating pipeline, the inlet of the heating pipeline is connected to the outlet of the heat storage component, and the outlet of the heating pipeline is connected to the inlet of the cold storage component; wherein, the first heat exchange pipeline of the refrigeration heat exchanger is connected to the refrigeration pipeline, and the second heat exchange pipeline of the refrigeration heat exchanger is connected to the first connecting pipeline; the third heat exchange pipeline of the heating heat exchanger is connected to the heating pipeline, and the fourth heat exchange pipeline of the heating heat exchanger is connected to the second connecting pipeline.

[0014] Furthermore, the refrigeration heat exchanger includes: a first refrigeration heat exchanger, which is arranged between a compressor adjacent to the air storage component among the multiple compressors and the air storage component; and / or a second refrigeration heat exchanger, which is arranged between two adjacent compressors among the multiple compressors.

[0015] Furthermore, the heat supply heat exchanger includes: a first heat supply heat exchanger, which is arranged between an air turbine adjacent to the air storage component among the multiple air turbines and the air storage component; and / or a second heat supply heat exchanger, which is arranged between two adjacent air turbines among the multiple air turbines.

[0016] Furthermore, the compressed air energy storage system includes: a first control valve, which is arranged at the gas storage outlet to control the opening and closing of the gas storage outlet; and / or a second control valve, which is arranged at the gas storage inlet to control the opening and closing of the gas storage inlet.

[0017] Applying the technical solution of the present application, the compressed air energy storage system of the present application includes: an air storage component, a first connecting pipeline, and a second connecting pipeline, wherein the air storage inlet of the air storage component is connected to the first connecting pipeline, and the air storage outlet of the air storage component is connected to the second connecting pipeline; a compressed air assembly, wherein the compressed air assembly is arranged on the first connecting pipeline, and the compressed air assembly includes multiple compressors and a refrigeration and heat exchanger, wherein the multiple compressors include a low-pressure compressor, a medium-pressure compressor, and a high-pressure compressor connected in series from the air inlet; an expansion work assembly, wherein the expansion work assembly is arranged on the second connecting pipeline, and the expansion work assembly includes multiple air turbines and a heat supply heat exchanger; a heat exchange assembly, wherein the heat exchange assembly is connected to the refrigeration and heat supply heat exchanger and the heat supply heat exchanger to provide heat extracted from refrigerating the compressed air in the first connecting pipeline to the compressed air in the second connecting pipeline; wherein the high-pressure compressor located near the air storage component includes a reciprocating compressor, and the exhaust volume of the reciprocating compressor is controlled by adjusting the opening and closing time of the reciprocating compressor's intake valve through the reciprocating compressor's stepless air volume adjustment actuator. In this way, the present application sets up the above-mentioned compressed air energy storage system, sets the high-pressure compressor in the compressed air component to a reciprocating compressor, so as to achieve high-efficiency air compression and storage in the fully variable back pressure working condition through the precise stepless air volume adjustment characteristics of the reciprocating compressor, and uses the heat exchange component to recover and utilize heat energy during the compression and expansion of the air, thereby significantly improving the energy conversion efficiency of the compressed air energy storage system, and solving the problem that the compressed air energy storage system in the prior art cannot achieve reliable, economical and efficient variable back pressure compression energy storage. It can not only store and release energy efficiently, but also flexibly adjust the output power according to the actual needs of the power grid. It is suitable for scenarios with large fluctuations in electricity demand, such as grid-connected energy storage of renewable energy such as wind power and solar energy, reducing electricity waste, improving the utilization rate of renewable energy, and providing important guarantees for the stability of the power grid. Especially in emergency situations where rapid adjustment of power supply is required, it can respond quickly to meet electricity demand, reduce dependence on fossil fuels, reduce carbon emissions, and have significant environmental benefits. In addition, the reciprocating compressor is driven by a constant-speed motor, which eliminates the need to use a frequency converter during variable operating conditions, thereby saving frequency conversion power loss and further improving the economy and work efficiency of the compressed air energy storage system. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The features and advantages of one or more embodiments of the present application will become more easily understood through the following description with reference to the accompanying drawings. The drawings described herein are for illustrative purposes only and are not intended to limit the scope of the present application in any way. The drawings are not drawn to scale and may exaggerate or reduce some features to show details of specific components. In the drawings:

[0019] Figure 1 A schematic structural diagram of an embodiment of a compressed air energy storage system according to the present application is shown;

[0020] Figure 2 Shows the gas passing through Figure 1 A schematic diagram of the state changes of various components in the compressed air energy storage system shown; and

[0021] Figure 3 Shown Figure 1 The figure shows a flow chart of the control of the opening and closing time of the intake valve by the stepless air volume regulation actuator of the high-pressure compressor of the compressed air energy storage system.

[0022] Description of Figure Numbers:

[0023] 100, first connecting pipeline 200, second connecting pipeline

[0024] 1. Air storage components 2. Compressed air components

[0025] 20. Refrigeration and heat exchanger 201. First refrigeration and heat exchanger

[0026] 202, second cooling and heat exchanger 203, first heat exchange pipeline

[0027] 204, second heat exchange pipeline 21, low-pressure compressor

[0028] 22. High-pressure compressor 23. Medium-pressure compressor

[0029] 3. Expansion work component 30. Heat exchanger

[0030] 301, first heat supply heat exchanger 302, second heat supply heat exchanger

[0031] 303, third heat exchange pipeline 304, fourth heat exchange pipeline

[0032] 31. Air Turbine 311. High-Pressure Air Turbine

[0033] 312. Low-pressure air turbine 32. Generator

[0034] 4. Heat exchange component 41. Heat storage component

[0035] 42. Cold storage components 43. Refrigeration pipelines

[0036] 431, refrigeration heat exchange branch 432, refrigeration heat exchange liquid delivery section

[0037] 433, refrigeration heat exchange return section 44, heating pipeline

[0038] 441. Heating branch 442. Heating liquid delivery section

[0039] 443, Heating return liquid section 5, first control valve

[0040] 6. Second control valve DETAILED DESCRIPTION

[0041] The following will be combined with the accompanying drawings in the embodiments of the present application to describe the technical solutions in the embodiments of the present application in detail. It should be noted that the embodiments of the present application and the features in the embodiments can be combined with each other if there is no conflict.

[0042] In the following detailed description, reference is made to the accompanying drawings that form a part of this specification, in which specific embodiments in which the application may be implemented are shown by way of illustration. With respect to the drawings, directional terms such as "top," "bottom," "inside," "outside," "up," "down," "front," "back," and the like are used with reference to the orientation of the drawings being described. Because the components of the embodiments of the present application can be placed in many different orientations, the directional terms are used for illustration only and are not intended to be limiting. It should be understood that other embodiments may be used and that structural or logical changes may be made without departing from the scope of the present application. Therefore, the following detailed description should not be construed in a limiting sense, and the application is defined by the appended claims.

[0043] like Figure 1 As shown, the present application provides a compressed air energy storage system, comprising: an air storage component 1, a first connecting pipeline 100 and a second connecting pipeline 200, wherein the air storage inlet of the air storage component 1 is connected to the first connecting pipeline 100, and the air storage outlet of the air storage component 1 is connected to the second connecting pipeline 200; a compressed air component 2, wherein the compressed air component 2 is arranged on the first connecting pipeline 100, and the compressed air component 2 includes a plurality of compressors and a refrigeration heat exchanger 20, wherein the plurality of compressors include a low-pressure compressor 21, a medium-pressure compressor 23 and a high-pressure compressor 22 connected in series from the air inlet; an expansion work component 3, wherein the expansion work component Component 3 is arranged on the second connecting pipeline 200, and the expansion working component 3 includes multiple air turbines 31 and a heat supply heat exchanger 30; the heat exchange component 4 is connected to the refrigeration heat exchanger 20 and the heat supply heat exchanger 30 to provide the heat extracted from the refrigeration of the compressed air in the first connecting pipeline 100 to the compressed air in the second connecting pipeline 200; wherein, the high-pressure compressor 22 at a position close to the air storage component 1 includes a reciprocating compressor to control the exhaust volume of the reciprocating compressor by adjusting the opening and closing time of the intake valve of the reciprocating compressor through the stepless air volume adjustment actuator of the reciprocating compressor.

[0044] In this way, the present application sets up the above-mentioned compressed air energy storage system, sets the high-pressure compressor 22 in the compressed air component 2 as a reciprocating compressor, and realizes high-efficiency air compression and storage in the full-variable back pressure working condition through the precise stepless air volume regulation characteristics of the reciprocating compressor, and utilizes the heat exchange component 4 to recover and utilize heat energy during the compression and expansion of the air, thereby significantly improving the energy conversion efficiency of the compressed air energy storage system, and solving the problem that the compressed air energy storage system in the prior art cannot achieve reliable, economical and efficient variable back pressure compression energy storage. It can not only store and release energy efficiently, but also flexibly adjust the output power according to the actual needs of the power grid. It is suitable for scenarios with large fluctuations in electricity demand, such as grid-connected energy storage of renewable energy such as wind power and solar energy, reducing electricity waste, improving the utilization rate of renewable energy, and providing important guarantees for the stability of the power grid. Especially in emergency situations where rapid adjustment of power supply is required, it can respond quickly to meet electricity demand, reduce dependence on fossil fuels, reduce carbon emissions, and have significant environmental benefits. In addition, the reciprocating compressor is driven by a constant-speed motor, which eliminates the need to use a frequency converter during variable operating conditions, thereby saving frequency conversion power loss and further improving the economy and work efficiency of the compressed air energy storage system.

[0045] In the compressed air energy storage system, the internal pressure of the gas storage component 1 (such as a gas tank) is low when it starts to inflate, close to the standard atmospheric pressure. As the high-pressure compressor 22 continues to pressurize the gas into the gas storage component 1, the gas pressure inside the gas storage component 1 will gradually increase until it reaches the pre-set maximum storage pressure. This process of increasing pressure means that the back pressure encountered by the high-pressure compressor 22 during the inflation process (i.e., the pressure inside the gas storage component) is also constantly increasing. The efficiency and energy consumption of the compressor are related to its outlet pressure. Under low back pressure conditions, the compressor does not need to run at full load, because at this time it does not need to overcome a very high outlet pressure to compress the gas. If the compressor runs at full load at this time, this may increase unnecessary energy consumption; as the back pressure increases, the compressor needs to gradually run at full load to compress the gas to a higher pressure.

[0046] The key effect of the reciprocating compressor used in the high-pressure compressor 22 of this application in the compressed air energy storage system is that its unique stepless air volume adjustment function solves the problem that the compressed air energy storage system in the prior art cannot achieve efficient and economical operation under variable back pressure conditions. Specifically, the relationship between the reciprocating compressor's exhaust volume adjustment and the problem solved by the system is reflected as follows:

[0047] (1) In the compressed air energy storage system, as the gas pressure in the gas storage component 1 gradually increases, the reciprocating compressor needs to work under a constantly changing back pressure condition. The ordinary compressor used in the high-pressure compressor 22 in the prior art often cannot guarantee high efficiency and economy under variable back pressure conditions, especially the compressor controlled by a variable frequency motor. Although it can cope with back pressure changes by adjusting the speed, its variable frequency operation will bring additional energy loss and structural complexity cost. The reciprocating compressor used in the high-pressure compressor 22 of the present application can accurately control the opening and closing time of its own intake valve through a built-in stepless air volume adjustment actuator, so as to flexibly adjust the exhaust volume during the compression process to adapt to the variable back pressure condition. The reciprocating compressor is located near the gas storage component 1. This feature allows it to automatically adjust the delayed closing time of its own intake valve according to the current gas pressure in the gas storage component 1, so that the actual compression time of the reciprocating compressor is less than the time required for the predetermined compression process when the intake valve is not delayed to close, thereby reducing the actual exhaust pressure of the reciprocating compressor and ensuring that the outlet pressure of the reciprocating compressor matches the gas pressure in the gas storage component 1.

[0048] (2) In the initial inflation stage of the compressed air energy storage system, the gas storage component 1 is like a container waiting to be filled, with its interior in a hollow state and a relatively low pressure. At this time, the reciprocating compressor faces a relatively small exhaust back pressure, that is, it encounters little resistance when delivering compressed gas to the gas storage component 1. At the same time, the medium-pressure compressor 23 continues to supply gas to the reciprocating compressor, which ensures that the total amount of gas to be compressed in the reciprocating compressor will not be reduced due to the delayed closing of its own intake valve, thereby ensuring the continuous flow of gas in the reciprocating compressor and the smooth progress of the compression process.

[0049] In order to optimize the energy utilization in this process, the compressed air energy storage system uses a stepless air volume adjustment actuator for the reciprocating compressor, which cleverly delays the closing time of the intake valve. This strategy shortens the time it takes for the piston of the reciprocating compressor to move upward to compress the gas, so that the compressed gas pressure is lower than the predetermined pressure that can be achieved under the above-mentioned predetermined compression process, thereby perfectly adapting to the current low back pressure environment. In other words, in the starting stage when the gas pressure inside the gas storage component 1 is relatively low, by reducing the actual compression time of the reciprocating compressor, the reciprocating compressor avoids unnecessary energy consumption, thereby improving the operating efficiency of the entire compressed air energy storage system.

[0050] like Figure 3As shown, the compression process of the compressed air energy storage system of the present application includes: S11, starting the compressed air energy storage system; S12, detecting the outlet pressure P1 at the gas outlet of the reciprocating compressor once at a predetermined time interval; S13, calculating the pressure difference ΔP=P1-P0 between the outlet pressure P1 and the predetermined pressure P0 corresponding to the predetermined compression process; S14, judging whether ΔP is zero; S15, when ΔP is not zero, calculating the delayed closing time of the intake valve of the reciprocating compressor according to the size of ΔP, and then controlling the delayed closing of the intake valve according to the delayed closing time; when ΔP is zero, controlling the intake valve to close on time.

[0051] As the compression process continues, the gas storage component 1 is gradually filled, and the gas pressure therein also increases, thereby increasing the exhaust back pressure of the reciprocating compressor. In this case, in order to maintain the efficient operation of the compressor, the stepless gas volume control actuator will gradually shorten the delayed closing time of the intake valve. In this way, the actual compression time of the reciprocating compressor gradually approaches the time required for the predetermined compression process, so that the pressure of the compressed gas gradually increases, ensuring that the reciprocating compressor can seamlessly adapt to the gradually increasing gas pressure inside the gas storage component 1 to maintain an energy-saving, stable and efficient inflation process.

[0052] The compressed air energy storage system of this application utilizes an innovative method to dynamically adjust the closing time of the reciprocating compressor's intake valve, enabling the high-pressure compressor 22 to not only accurately match changing backpressure conditions but also significantly reduce energy consumption throughout the entire charging cycle. In compressed air energy storage systems, this strategy not only demonstrates the wisdom of structural design but, more importantly, achieves maximum energy conservation while meeting energy storage requirements, which is particularly important in today's pursuit of economic efficiency, sustainable development, and energy efficiency.

[0053] (3) During operation under variable back pressure conditions, the stepless air volume regulation characteristics of the reciprocating compressor enable it to accurately adapt to variable back pressure conditions, and automatically adjust the exhaust pressure to match the gas pressure changes in the gas storage component 1. There is no need to adjust the speed by using a frequency converter, which avoids the efficiency loss and equipment complexity caused by variable frequency regulation in the existing technology, reduces additional energy loss, and improves compression efficiency. The fixed speed motor drive method adopted by the reciprocating compressor also reduces the investment cost of the variable frequency equipment and the power loss during operation, and realizes the efficient, stable and economical operation of the compressed air energy storage system in the full range of operating conditions. It not only improves the overall thermodynamic efficiency of the compressed air energy storage system, but also improves the flexibility and response speed of the compressed air energy storage system, so that it can better adapt to the fluctuations in grid demand, especially when dealing with power fluctuations when renewable energy is connected to the grid, thereby improving the economic benefits and environmental performance of the compressed air energy storage system. In short, as the gas pressure inside the gas storage component 1 gradually accumulates from low to high, the reciprocating compressor effectively achieves a dynamic balance between the compressed gas volume and pressure by progressively adjusting the delayed closing time of its own intake valve, ensuring that even when the back pressure changes, the gas can be compressed and stored with minimal energy consumption, demonstrating the economy and efficiency of the compressed air energy storage system in energy management.

[0054] Specifically, the compressed air energy storage system of the present application also includes a control module, which is connected to components such as the compressed air assembly 2. Through integrated control, a stable and efficient variable back pressure compression process and high working efficiency are achieved. No manual operation or start and stop are required to achieve a smooth variable back pressure process, which greatly improves the intelligence, automation, stability and reliability of the compressed air energy storage system.

[0055] The "cooling and heating" in the cooling and heating heat exchanger 20 means that during the operation of the compressed air energy storage system, the air flowing through the first connecting pipe 100 will heat up when it is compressed. The heat generated in this process can be extracted and stored (i.e., heat extraction) through the cooling and heating heat exchanger 20, while cooling the air in the first connecting pipe 100 (i.e., cooling) so as to more effectively store the compressed air. During the air compression stage, the cooling and heating heat exchanger 20 absorbs heat from the compressed air to prevent the compressed air temperature from being too high and improve the compression efficiency; during the compressed air expansion and power generation stage, the heating heat exchanger 30 releases the stored heat back to the compressed air flowing through the second connecting pipe 200, thereby improving the expansion efficiency and energy recovery rate of the compressed air. The entire process utilizes the recovery and reuse of heat energy, which not only improves the thermodynamic efficiency of the compressed air energy storage system and reduces energy waste, but also improves the economic benefits and environmental performance of the compressed air energy storage system.

[0056] The low-pressure compressor 21 is the first stage in the entire standard atmospheric compression process, responsible for initially raising the standard atmospheric pressure of air (approximately 1 standard atmosphere, or 101,325 Pascals) to a lower intermediate pressure, resulting in the first stage of compressed gas. Typically, the low-pressure compressor 21 is designed to process large volumes of air, but due to its smaller compression ratio, the required compression force is also smaller.

[0057] The intermediate-pressure compressor 23, following the low-pressure compressor, is the second stage of the compression process. It continues to raise the lower intermediate pressure of the first-stage compressed gas to a higher intermediate pressure. Its function is to further compress the already initially compressed first-stage compressed gas to reach the final intermediate pressure within the high-pressure range required, producing the second-stage compressed gas. Compared to the low-pressure compressor 21, the intermediate-pressure compressor 23 processes a smaller volume of air but exerts greater compression force.

[0058] The high-pressure compressor 22 is the last stage of the compression process, responsible for further compressing the secondary compressed gas after being compressed step by step by the low-pressure compressor 21 and the medium-pressure compressor 23 to the final required high-pressure state to obtain the tertiary compressed gas, whose pressure is sufficient to meet the energy storage requirements, usually higher than 100 standard atmospheric pressures. The high-pressure compressor 22 of this application adopts a reciprocating compressor, which can withstand higher working pressures to more efficiently process high-pressure gas, and can accurately control the outlet pressure at the gas outlet of the high-pressure compressor 22 through the stepless gas volume adjustment actuator, meet the requirements of variable back pressure compression energy storage, and have good air tightness.

[0059] The hierarchical use of the above-mentioned low-pressure compressor 21, medium-pressure compressor 23 and high-pressure compressor 22 is to improve the efficiency and reliability of the entire compressed air energy storage system. By dividing the compression process of the air before entering the air storage component 1 into three stages, the compressor of each stage only needs to deal with a relatively small pressure difference, reducing the risk of a single-stage compressor having to bear an excessive pressure burden, thereby improving the efficiency and life of the compressor. At the same time, multi-stage compression can also allow for better thermal management during the compression process. By using a refrigeration heat exchanger 20 to cool the air after each compression stage, the energy loss during the air compression process is reduced and the overall thermodynamic efficiency of the compressed air energy storage system is improved.

[0060] Optionally, the pressure of the air at the gas outlet of the low-pressure compressor 21 is greater than the pressure of the air at the gas inlet of the low-pressure compressor 21; the low-pressure compressor 21 includes: an integrally geared centrifugal compressor; or multiple integrally geared centrifugal compressors, and the multiple integrally geared centrifugal compressors are arranged in series or in parallel with each other.

[0061] Due to the efficient compression characteristics of the integrally geared centrifugal compressor, the energy conversion efficiency of the low-pressure compression stage of the compressed air component 2 is further improved, so that the air can be compressed with lower energy loss in the low-pressure compression stage, achieving efficient energy storage, and overall improving the economy and environmental protection of the compressed air energy storage system.

[0062] When the pressure range of the air storage component 1 is relatively wide, multiple integrally geared centrifugal compressors can be connected in series to achieve high-efficiency compression over the entire pressure range; when the flow rate in the compressed air energy storage system is large, multiple integrally geared centrifugal compressors can be connected in parallel to achieve the goals of large flow rate and high power.

[0063] Optionally, the pressure of the air at the gas inlet of the medium-pressure compressor 23 is greater than the pressure of the air at the gas inlet of the low-pressure compressor 21, the pressure of the air at the gas outlet of the medium-pressure compressor 23 is equal to the pressure of the air at the gas outlet of the low-pressure compressor 21, and the pressure of the air at the gas outlet of the medium-pressure compressor 23 is greater than the pressure of the air at the gas inlet of the medium-pressure compressor 23; the medium-pressure compressor 23 includes an integrally geared centrifugal compressor; or multiple integrally geared centrifugal compressors, and the multiple integrally geared centrifugal compressors are arranged in series or in parallel with each other.

[0064] Due to the efficient compression characteristics of the integrally geared centrifugal compressor, the energy conversion efficiency of the medium-pressure compression stage of the compressed air component 2 is further improved, so that the compressed air can be further compressed with lower energy loss in the medium-pressure compression stage, achieving efficient energy storage and improving the overall economy and environmental protection of the compressed air energy storage system.

[0065] When the pressure range of the air storage component 1 is relatively wide, multiple integrally geared centrifugal compressors can be connected in series to achieve high-efficiency compression over the entire pressure range; when the flow rate in the compressed air energy storage system is large, multiple integrally geared centrifugal compressors can be connected in parallel to achieve the goals of large flow rate and high power.

[0066] Optionally, the pressure of the air at the gas inlet of the high-pressure compressor 22 is greater than the pressure of the air at the gas inlet of the medium-pressure compressor 23, the pressure of the air at the gas outlet of the high-pressure compressor 22 is equal to the pressure of the air at the gas outlet of the medium-pressure compressor 23, and the pressure of the air at the gas outlet of the high-pressure compressor 22 is greater than the pressure of the air at the gas inlet of the high-pressure compressor 22; the high-pressure compressor 22 includes a reciprocating compressor; or multiple reciprocating compressors, and the multiple reciprocating compressors are arranged in series or in parallel with each other.

[0067] Due to the stepless air volume regulation characteristics of the reciprocating compressor, it can quickly adjust its working state when facing different load demands, improving the response speed and adaptability of the compressed air energy storage system, and is suitable for power peak-shaving scenarios that require rapid response. Therefore, through the flexible adjustment of the reciprocating compressor, the compressed air energy storage system can maintain efficient operation under different power demands, and is suitable for scenarios with rapidly changing power demand, such as power supply in commercial areas and peak-shaving demands of smart grids, effectively improving the flexibility and stability of the power system, and providing strong support for the balance of power supply and demand.

[0068] When the pressure range of the air storage component 1 is relatively wide, multiple reciprocating compressors can be connected in series to achieve high-efficiency compression over the entire pressure range; when the flow rate in the compressed air energy storage system is large, multiple reciprocating compressors can be connected in parallel to achieve the goals of large flow rate and high power.

[0069] The above-mentioned multi-stage compression setting can effectively reduce the load of a single-stage compressor, improve the compression efficiency and stability of the overall system, and reduce energy loss. It is suitable for scenarios that require long-term, large-capacity energy storage, such as backup power systems for industrial electricity. It ensures stable and reliable power support during peak power demand, reduces the operating costs of industrial production, improves production efficiency, and also reduces the impact of industry on the environment, promoting the green transformation of industry.

[0070] The compressed air energy storage system of this application utilizes an integrally geared centrifugal compressor as the front-end and middle-stage compression equipment, and a reciprocating compressor as the final-stage boosting equipment. This achieves a smoothly variable backpressure function in the compressed air assembly 2, enabling a reliable and efficient compression and energy storage process. Furthermore, the reciprocating compressor's stepless air volume control actuator can be used to automatically balance and match airflow and outlet pressure, maximizing energy savings while maintaining smooth and reliable operation.

[0071] An air turbine 31 , also known as an air turbine or expander, is a device that uses the expansion of high-pressure gas (usually compressed air) to generate mechanical work. Its working principle is similar to that of a steam turbine, but it uses compressed air as the working fluid instead of steam.

[0072] like Figure 1 As shown, the expansion work component 3 of the compressed air energy storage system of the present application includes: a generator 32, and an air turbine 31 and the generator 32 are mechanically driven and connected.

[0073] In this way, the mechanical drive connection between the air turbine 31 and the generator can directly drive the generator to generate power, simplifying the energy conversion process, improving the energy conversion efficiency, and realizing a scenario of rapid response and high-efficiency energy release. It can provide emergency power support for the power grid, effectively improve the stability and reliability of electricity, reduce the risk of power supply interruption, and provide a strong guarantee for the balance of power supply and demand.

[0074] like Figure 1 As shown, the expansion working component 3 of the compressed air energy storage system of the present application includes a high-pressure air turbine 311, the gas inlet of the high-pressure air turbine 311 is connected to the gas storage outlet; and a low-pressure air turbine 312, the gas inlet of the low-pressure air turbine 312 is connected to the gas outlet of the high-pressure air turbine 311; wherein, the high-pressure air turbine 311 and the low-pressure air turbine 312 are mechanically driven and connected, and the low-pressure air turbine 312 and the generator 32 are mechanically driven and connected.

[0075] The combination of the above-mentioned high-pressure air turbine 311 and the low-pressure air turbine 312 enables the compressed air energy storage system to fully utilize the compressed air flowing out of the air storage component 1, thereby improving the flexibility and efficiency of energy release and the energy efficiency of the compressed air energy storage system. It is particularly suitable for scenarios that require stable output under different load conditions, such as the power supply in commercial areas. It effectively responds to fluctuations in power demand, improves the adaptability and stability of the power system, provides stable and reliable power support for commercial areas, reduces the cost of power supply, and improves the efficiency of commercial operations.

[0076] like Figure 1 As shown, the heat exchange assembly 4 of the compressed air energy storage system of the present application includes a heat storage component 41 and a cold storage component 42; a refrigeration pipeline 43, the outlet of the refrigeration pipeline 43 is connected to the inlet of the heat storage component 41, and the inlet of the refrigeration pipeline 43 is connected to the outlet of the cold storage component 42; a heating pipeline 44, the inlet of the heating pipeline 44 is connected to the outlet of the heat storage component 41, and the outlet of the heating pipeline 44 is connected to the inlet of the cold storage component 42; wherein, the first heat exchange pipeline 203 of the refrigeration heat exchanger 20 is connected to the refrigeration pipeline 43, and the second heat exchange pipeline 204 of the refrigeration heat exchanger 20 is connected to the first connecting pipeline 100; the third heat exchange pipeline 303 of the heating heat exchanger 30 is connected to the heating pipeline 44, and the fourth heat exchange pipeline 304 of the heating heat exchanger 30 is connected to the second connecting pipeline 200.

[0077] In this way, the heat energy recovery and reuse of the air flow during the compression and expansion process is realized, which significantly improves the overall energy efficiency of the compressed air energy storage system, achieves high energy efficiency and environmental protection effects, reduces the waste of heat energy, reduces energy consumption, and reduces the impact on the environment, providing strong support for the sustainable development of energy. At the same time, it also provides users with a more stable and reliable power supply, improving the quality of urban life.

[0078] like Figure 1 As shown, the specific structure of the refrigeration and heat exchanger 20 used in the compressed air energy storage system of the present application includes a first heat exchange shell and a first fluid pipeline arranged through the first heat exchange shell. The first annular space formed between the first heat exchange shell and the first fluid pipeline is the first heat exchange pipeline 203, and the first fluid pipeline is the second heat exchange pipeline 204. The refrigerant flowing into the first annular space from the refrigeration pipeline 43 and the compressed air flowing into the first fluid pipeline from the first connecting pipeline 100 are heat exchanged through the first fluid pipeline.

[0079] like Figure 1 As shown, the specific structure of the heat supply heat exchanger 30 adopted in the compressed air energy storage system of the present application includes a second heat exchange shell and a second fluid pipeline arranged through the second heat exchange shell. The second annular space formed between the second heat exchange shell and the second fluid pipeline is the third heat exchange pipeline 303, and the second fluid pipeline is the fourth heat exchange pipeline 304. The refrigerant flowing into the second annular space from the heating pipeline 44 and the compressed air flowing into the second fluid pipeline from the second connecting pipeline 200 are heat exchanged through the second fluid pipeline.

[0080] Specifically, when the low-temperature refrigerant from the cold storage component 42 in the cooling pipeline 43 enters the first heat exchange pipeline 203 of the refrigeration heat exchanger 20, it will cool the compressed air from the front-end compressor and enter the corresponding second heat exchange pipeline 204 of the refrigeration heat exchanger 20 through the first connecting pipeline 100, and then become high-temperature refrigerant and finally enter the heat storage component 41, and the cooled compressed air will eventually flow into the gas storage component 1; when the high-temperature refrigerant from the heat storage component 41 in the heating pipeline 44 enters the third heat exchange pipeline 303 of the heating heat exchanger 30, it will heat the compressed air from the gas storage component 1 or the front-end air turbine and enter the fourth heat exchange pipeline 304 of the heating heat exchanger 30 through the second connecting pipeline 200, and then become low-temperature refrigerant and finally enter the cold storage component 42, and the heated compressed air will eventually flow into the external air environment.

[0081] like Figure 1As shown, in the compressed air energy storage system of the present application, the refrigeration and heat exchanger 20 includes: a first refrigeration and heat exchanger 201, which is arranged between a compressor adjacent to the air storage component 1 among the multiple compressors and the air storage component 1; and / or a second refrigeration and heat exchanger 202, which is arranged between two adjacent compressors among the multiple compressors.

[0082] like Figure 1 As shown, the heat supply heat exchanger 30 includes: a first heat supply heat exchanger 301, which is arranged between an air turbine 31 adjacent to the air storage component 1 among the multiple air turbines 31 and the air storage component 1; and / or a second heat supply heat exchanger 302, which is arranged between two adjacent air turbines 31 among the multiple air turbines 31.

[0083] The above-mentioned multi-point heat exchange setting further optimizes the thermal energy management efficiency of the compressed air energy storage system, makes the recovery and utilization of the heat energy of the air during the compression and expansion process more sufficient, and improves the stability and reliability of the compressed air energy storage system.

[0084] In one embodiment of the present application, the number of first refrigeration heat exchangers 201 is one, and one first refrigeration heat exchanger 201 is arranged between the compressed air component 2 and the air storage component 1, that is, between the high-pressure compressor 22 and the air storage component 1; the number of second refrigeration heat exchangers 202 is two, one second refrigeration heat exchanger 202 is arranged between the low-pressure compressor 21 and the medium-pressure compressor 23, and the other second refrigeration heat exchanger 202 is arranged between the medium-pressure compressor 23 and the high-pressure compressor 22; the number of first heat supply heat exchangers 301 is one, and one first heat supply heat exchanger 301 is arranged between the expansion work component 3 and the air storage component 1, that is, between the high-pressure air turbine 311 and the air storage component 1; the number of second heat supply heat exchangers 302 is one, and one second heat supply heat exchanger 302 is arranged between the high-pressure air turbine 311 and the low-pressure air turbine 312.

[0085] like Figure 1As shown, the refrigeration pipeline 43 includes three refrigeration heat exchange branches 431, which are connected one by one to a first refrigeration heat exchanger 201 and two refrigeration heat exchanger branches 431 on the second refrigeration heat exchanger 202 in parallel, and each refrigeration heat exchange branch 431 includes a refrigeration heat exchange liquid supply section 432 and a refrigeration heat exchange return liquid section 433; wherein, the inlet of the refrigeration heat exchange liquid supply section 432 is connected to the outlet of the cold storage component 42, the outlet of the refrigeration heat exchange liquid supply section 432 is connected to the inlet of the first heat exchange pipeline 203 of the corresponding refrigeration heat exchanger 20, the inlet of the refrigeration heat exchange return liquid section 433 is connected to the outlet of the first heat exchange pipeline 203 of the corresponding refrigeration heat exchanger 20, and the outlet of the refrigeration heat exchange return liquid section 433 is connected to the inlet of the heat storage component 41.

[0086] like Figure 1 As shown, the heating pipeline 44 includes two heating branches 441, which are respectively connected to a first heating heat exchanger 301 and a second heating heat exchanger 302 in parallel, and each heating branch 441 includes a heating liquid supply section 442 and a heating liquid return section 443; wherein, the inlet of the heating liquid supply section 442 is connected to the outlet of the heat storage component 41, the outlet of the heating liquid supply section 442 is connected to the inlet of the third heat exchange pipeline 303 of the corresponding heating heat exchanger 30, the inlet of the heating liquid return section 443 is connected to the outlet of the third heat exchange pipeline 303 of the corresponding heating heat exchanger 30, and the outlet of the heating liquid return section 443 is connected to the inlet of the cold storage component 42.

[0087] It should be noted that the total heat exchange capacity of the cooling heat exchanger and the total heat exchange capacity of the heating heat exchanger must be kept the same, which depends on the configuration requirements of the compressed air energy storage system and the specific models of the compressor and air turbine.

[0088] like Figure 1 As shown, the compressed air energy storage system of the present application includes a first control valve 5, which is arranged at the gas storage outlet to control the opening and closing of the gas storage outlet; and / or a second control valve 6, which is arranged at the gas storage inlet to control the opening and closing of the gas storage inlet.

[0089] The first control valve 5 and the second control valve 6 have nothing to do with the control of the high-pressure compressor 22 and the like, and are only used to control when the gas storage component 1 is inflated or deflated.

[0090] The compressed air energy storage system of the present application not only improves the operational flexibility of the compressed air energy storage system by setting the first control valve 5 and the second control valve 6, but also enhances the safety of the compressed air energy storage system, so that the compressed air energy storage system can quickly adjust the working state according to actual needs. It is particularly suitable for scenarios that require high automation and remote control, such as the energy storage system of the smart grid. It effectively improves the intelligence level of the power system and provides a strong guarantee for the stable operation of the power grid. At the same time, it also reduces the cost of power supply, improves the efficiency of power utilization, and promotes the green transformation of the power industry.

[0091] The working process of the reciprocating compressor of the compressed air energy storage system of this application is as follows:

[0092] (1) When the reciprocating compressor (i.e., the high-pressure compressor 22) starts to deliver air to the air storage component 1, the back pressure of the reciprocating compressor is the minimum pressure in the air storage component 1; at this time, the actual exhaust pressure of the reciprocating compressor is smaller than the predetermined pressure corresponding to the predetermined compression process. By delaying the closing of the valve plate of the intake valve of the reciprocating compressor through the stepless air volume adjustment actuator of the reciprocating compressor, the final exhaust pressure of the reciprocating compressor can be reduced while ensuring the constant pressure at the inlet of the reciprocating compressor, so as to provide a stable back pressure to the integral gear centrifugal compressor (i.e., the low-pressure compressor 21 or the medium-pressure compressor 23) in the front section.

[0093] (2) During the gradual pressure increase, the stepless air volume control actuator of the reciprocating compressor can automatically calculate and reduce the delayed closing time of the intake valve to adjust the actual exhaust pressure of the reciprocating compressor until the pressure in the air storage component 1 reaches the maximum. During the pressure increase, since the actual exhaust pressure of the reciprocating compressor is adjusted by controlling the intake volume of the reciprocating compressor, the shaft power of the reciprocating compressor increases linearly to reach the final rated value. Therefore, under the premise of ensuring the stable and reliable operation of the reciprocating compressor, energy consumption is maximized. In addition, the reciprocating compressor is driven by a fixed speed motor and does not have a frequency conversion device, which reduces the corresponding production cost and power loss.

[0094] like Figure 2 As shown in Figure 1, in a compressed air energy storage system, the state of the gas (usually air) will change significantly at each component. These changes run through the two main processes of the compressed air energy storage system: charging energy storage and discharging power generation:

[0095] S21: Gas filling and energy storage process:

[0096] S211 : The air in the external environment is initially at a standard atmospheric pressure and temperature state, and enters the first connecting pipeline 100 through the air inlet of the first connecting pipeline 100 .

[0097] S212: The air enters the low-pressure compressor 21 and is initially compressed in the low-pressure compressor 21. The pressure and temperature of the air increase, and the volume of the air decreases. However, the increased pressure and temperature increase the energy of the air to form a first-stage high-temperature compressed gas.

[0098] S213: The first-stage high-temperature compressed gas flowing out of the low-pressure compressor 21 will be cooled by the second refrigeration and heat exchanger 202 located between the low-pressure compressor 21 and the medium-pressure compressor 23. The low-temperature refrigerant flowing through the second refrigeration and heat exchanger 202 takes away the heat generated during the first compression process when forming the first-stage high-temperature compressed gas, so as to form a high-temperature refrigerant and recover it and store it in the heat storage component 41 of the heat exchange assembly 4, and form a first-stage low-temperature compressed gas.

[0099] S214: The first-stage low-temperature compressed gas coming out of a first refrigeration heat exchanger 201 enters the intermediate-pressure compressor 23, and is further compressed to a higher pressure in the intermediate-pressure compressor 23, undergoing pressure and temperature increase again, and the air volume is further reduced to form a second-stage high-temperature compressed gas.

[0100] S215: The secondary high-temperature compressed gas flowing out of the medium-pressure compressor 23 will be cooled by the second refrigeration and heat exchanger 202 located between the medium-pressure compressor 23 and the high-pressure compressor 22. The low-temperature refrigerant flowing through the second refrigeration and heat exchanger 202 takes away the heat generated during the second compression process when forming the secondary high-temperature compressed gas, so as to form a high-temperature refrigerant and recover it and store it in the heat storage component 41 of the heat exchange assembly 4, and form a secondary low-temperature compressed gas.

[0101] S216: The secondary low-temperature compressed gas coming out of another first refrigeration and heat exchanger 201 enters the high-pressure compressor 22, and is finally compressed to the highest target pressure by the high-pressure compressor 22 to form a three-stage high-temperature compressed gas; the high-pressure compressor 22 controls the compression ratio by adjusting the opening and closing time of the intake valve to ensure that the lifting and lowering pressures of the formed three-stage high-temperature compressed gas match the gas pressure inside the gas storage component 1.

[0102] S217: The three-stage high-temperature compressed gas flowing out of the high-pressure compressor 22 will be cooled by the first refrigeration and heat exchanger 201 located between the high-pressure compressor 22 and the gas storage component 1. The low-temperature refrigerant flowing through the first refrigeration and heat exchanger 201 takes away the heat generated during the third compression process when forming the three-stage high-temperature compressed gas, so as to form a high-temperature refrigerant and recover it and store it in the heat storage component 41 of the heat exchange component 4, and form a three-stage low-temperature compressed gas.

[0103] S218: The tertiary low-temperature compressed gas coming out of the first refrigeration and heat exchanger 201 is stored in the gas storage component 1, waiting for subsequent energy release.

[0104] S22: Degassing power generation process:

[0105] S221 : The high-pressure and low-temperature gas in the gas storage component 1 begins to be released into the second connecting pipeline 200 . The initial state of the air pressure and temperature depends on the current gas storage condition of the gas storage component 1 .

[0106] Step S222: The gas first passes through the first heat supply heat exchanger 301 to be heated by the high-temperature refrigerant flowing through the first heat supply heat exchanger 301 to form a low-temperature refrigerant and is recovered and stored in the cold storage component 42 of the heat exchange assembly 4 to form a high-pressure and high-temperature gas.

[0107] S223: The high-pressure air coming out of the first heat supply heat exchanger 301 passes through the high-pressure air turbine 311, expands in the high-pressure air turbine 311 to drive the high-pressure air turbine 311 to rotate, so that the high-pressure air turbine 311 drives the generator 32 to rotate through the low-pressure air turbine 312 to generate electricity. At this time, the pressure and temperature of the air decrease, but the volume increases to form a first-level low-temperature expanded gas.

[0108] S224: The first-stage low-temperature expansion gas coming out of the high-pressure air turbine 311 passes through the second heat supply heat exchanger 302 to be heated by the high-temperature refrigerant flowing through the second heat supply heat exchanger 302 to form a low-temperature refrigerant and is recovered and stored in the cold storage component 42 of the heat exchange component 4 to form a first-stage high-temperature expansion gas.

[0109] S225: The first-stage high-temperature expanded gas coming out of the second heat supply heat exchanger 302 enters the low-pressure air turbine 312, and further expands in the low-pressure air turbine 312 to drive the low-pressure air turbine 312 to rotate, so that the low-pressure air turbine 312 drives the generator 32 to rotate and generate electricity. At this time, the pressure and temperature of the first-stage high-temperature expanded gas are further reduced, and the volume continues to increase to form a second-stage low-temperature expanded gas.

[0110] S226 : The secondary low-temperature expanded gas eventually expands to air at a pressure and temperature close to standard atmospheric pressure, and is discharged through the air outlet of the second connecting pipeline 200 .

[0111] During the entire process of inflation and energy storage and deflation for power generation, the compressed air energy storage system achieves efficient storage and release of energy through multi-stage compression and expansion technology of air, as well as recovery and reuse of heat energy. Multi-stage compression reduces the efficiency loss of single-stage compression, and the recovered heat energy can be used to improve the expansion efficiency of compressed air during the expansion phase, reducing energy waste. The system is designed to use a reciprocating compressor as the high-pressure compressor 22, and through the stepless air volume adjustment method, it ensures that the compressed air energy storage system can operate stably under variable back pressure conditions, thereby improving compression efficiency and economy.

[0112] From the above description, it can be seen that the above embodiments of the present application achieve the following technical effects:

[0113] The compressed air energy storage system of the present application includes: an air storage component 1, a first connecting pipeline 100 and a second connecting pipeline 200, the air storage inlet of the air storage component 1 is connected to the first connecting pipeline 100, and the air storage outlet of the air storage component 1 is connected to the second connecting pipeline 200; a compressed air component 2, the compressed air component 2 is arranged on the first connecting pipeline 100, and the compressed air component 2 includes a plurality of compressors and a refrigeration and heat exchanger 20, the plurality of compressors include a low-pressure compressor 21, a medium-pressure compressor 23 and a high-pressure compressor 22 connected in series from the air inlet; an expansion work component 3, the expansion work component 3 is provided Located on the second connecting pipeline 200, the expansion working component 3 includes multiple air turbines 31 and a heat supply heat exchanger 30; the heat exchange component 4 is connected to the refrigeration heat exchanger 20 and the heat supply heat exchanger 30 to provide the heat extracted by refrigerating the compressed air in the first connecting pipeline 100 to the compressed air in the second connecting pipeline 200; wherein, the high-pressure compressor 22 at a position close to the air storage component 1 includes a reciprocating compressor to control the exhaust volume of the reciprocating compressor by adjusting the opening and closing time of the intake valve of the reciprocating compressor through the stepless air volume adjustment actuator of the reciprocating compressor. In this way, the present application sets up the above-mentioned compressed air energy storage system, sets the high-pressure compressor 22 in the compressed air component 2 as a reciprocating compressor, and realizes high-efficiency air compression and storage in the full-variable back pressure working condition through the precise stepless air volume regulation characteristics of the reciprocating compressor, and utilizes the heat exchange component 4 to recover and utilize heat energy during the compression and expansion of the air, thereby significantly improving the energy conversion efficiency of the compressed air energy storage system, and solving the problem that the compressed air energy storage system in the prior art cannot achieve reliable, economical and efficient variable back pressure compression energy storage. It can not only store and release energy efficiently, but also flexibly adjust the output power according to the actual needs of the power grid. It is suitable for scenarios with large fluctuations in electricity demand, such as grid-connected energy storage of renewable energy such as wind power and solar energy, reducing electricity waste, improving the utilization rate of renewable energy, and providing important guarantees for the stability of the power grid. Especially in emergency situations where rapid adjustment of power supply is required, it can respond quickly to meet electricity demand, reduce dependence on fossil fuels, reduce carbon emissions, and have significant environmental benefits. In addition, the reciprocating compressor is driven by a constant-speed motor, which eliminates the need to use a frequency converter during variable operating conditions, thereby saving frequency conversion power loss and further improving the economy and work efficiency of the compressed air energy storage system.

[0114] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or combinations thereof.

[0115] Unless otherwise specifically stated, the relative arrangement of the parts and steps, numerical expressions and numerical values set forth in these embodiments do not limit the scope of the present application. At the same time, it should be understood that, for ease of description, the sizes of the various parts shown in the drawings are not drawn according to actual proportional relationships. The techniques, methods and equipment known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, the techniques, methods and equipment should be considered as part of the authorization specification. In all examples shown and discussed here, any specific values should be interpreted as being merely exemplary and not as limitations. Therefore, other examples of the exemplary embodiments may have different values. It should be noted that similar numbers and letters represent similar items in the following figures, and therefore, once an item is defined in one figure, it does not need to be further discussed in subsequent figures.

[0116] In the description of this application, it should be understood that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "horizontal, vertical, vertical, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the device or element referred to must have a specific direction or be constructed and operated in a specific direction. Therefore, they cannot be understood as limiting the scope of protection of this application; the directional words "inside and outside" refer to the inside and outside relative to the outline of each component itself.

[0117] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used herein to describe the spatial positional relationship of a device or feature to other devices or features as shown in the figures. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figures. For example, if the device in the drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0118] In addition, it should be noted that the use of terms such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore cannot be understood as limiting the scope of protection of this application.

[0119] The foregoing description is merely a preferred embodiment of the present application and is not intended to limit the present application. Various modifications and variations are readily apparent to those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present application shall be included within the scope of protection of the present application.

Claims

1. A compressed air energy storage system, characterized in that: include: An air storage component (1), a first connecting pipeline (100) and a second connecting pipeline (200), wherein the air storage inlet of the air storage component (1) is connected to the first connecting pipeline (100), and the air storage outlet of the air storage component (1) is connected to the second connecting pipeline (200); A compressed air component (2), the compressed air component (2) being arranged on the first connecting pipeline (100), the compressed air component (2) comprising a plurality of compressors and a refrigeration and heat exchanger (20), the plurality of compressors comprising a low-pressure compressor (21), a medium-pressure compressor (23) and a high-pressure compressor (22) connected in series from an air inlet; an expansion work assembly (3), the expansion work assembly (3) being arranged on the second connecting pipeline (200), the expansion work assembly (3) comprising a plurality of air turbines (31) and a heat supply heat exchanger (30); a heat exchange component (4), the heat exchange component (4) being connected to the cooling heat exchanger (20) and the heating heat exchanger (30) to provide heat extracted from cooling the compressed air in the first connecting pipeline (100) to the compressed air in the second connecting pipeline (200); The high-pressure compressor (22) located near the air storage component (1) includes a reciprocating compressor, and the exhaust volume of the reciprocating compressor is controlled by adjusting the opening and closing time of the intake valve of the reciprocating compressor through the stepless air volume adjustment actuator of the reciprocating compressor.

2. The compressed air energy storage system according to claim 1, characterized in that: The pressure of the air at the gas outlet of the low-pressure compressor (21) is greater than the pressure of the air at the gas inlet of the low-pressure compressor (21); the low-pressure compressor (21) comprises: an integrally geared centrifugal compressor; or A plurality of integrally geared centrifugal compressors are provided, wherein the plurality of integrally geared centrifugal compressors are arranged in series or in parallel with each other.

3. The compressed air energy storage system according to claim 1, characterized in that: The pressure of the air at the gas inlet of the high-pressure compressor (22) is greater than the pressure of the air at the gas inlet of the medium-pressure compressor (23), and the pressure of the air at the gas outlet of the high-pressure compressor (22) is greater than the pressure of the air at the gas inlet of the high-pressure compressor (22); The high-pressure compressor (22) comprises: a said reciprocating compressor; or The plurality of reciprocating compressors are arranged in series or in parallel with each other.

4. The compressed air energy storage system according to claim 1, characterized in that: The pressure of the air at the gas inlet of the medium-pressure compressor (23) is greater than the pressure of the air at the gas inlet of the low-pressure compressor (21), and the pressure of the air at the gas outlet of the medium-pressure compressor (23) is greater than the pressure of the air at the gas inlet of the medium-pressure compressor (23); the medium-pressure compressor (23) comprises: an integrally geared centrifugal compressor; or A plurality of integrally geared centrifugal compressors are provided, wherein the plurality of integrally geared centrifugal compressors are arranged in series or in parallel with each other.

5. The compressed air energy storage system according to any one of claims 1 to 4, characterized in that: The expansion work component (3) includes a generator (32), and the air turbine (31) is mechanically driven to the generator (32).

6. The compressed air energy storage system according to claim 5, characterized in that: The plurality of air turbines (31) include: a high-pressure air turbine (311), wherein a gas inlet of the high-pressure air turbine (311) is connected to the gas storage outlet; a low-pressure air turbine (312), wherein a gas inlet of the low-pressure air turbine (312) is connected to a gas outlet of the high-pressure air turbine (311); The high-pressure air turbine (311) is mechanically driven to connect with the low-pressure air turbine (312), and the low-pressure air turbine (312) is mechanically driven to connect with the generator (32).

7. The compressed air energy storage system according to any one of claims 1 to 4, characterized in that: The heat exchange component (4) comprises: A heat storage component (41) and a cold storage component (42); A refrigeration pipeline (43), wherein the outlet of the refrigeration pipeline (43) is connected to the inlet of the heat storage component (41), and the inlet of the refrigeration pipeline (43) is connected to the outlet of the cold storage component (42); A heating pipeline (44), wherein the inlet of the heating pipeline (44) is connected to the outlet of the heat storage component (41), and the outlet of the heating pipeline (44) is connected to the inlet of the cold storage component (42); in, The first heat exchange pipeline (203) of the refrigeration heat exchanger (20) is connected to the refrigeration pipeline (43), and the second heat exchange pipeline (204) of the refrigeration heat exchanger (20) is connected to the first connecting pipeline (100); The third heat exchange pipeline (303) of the heat supply heat exchanger (30) is connected to the heating pipeline (44), and the fourth heat exchange pipeline (304) of the heat supply heat exchanger (30) is connected to the second connecting pipeline (200).

8. The compressed air energy storage system according to claim 7, characterized in that: The refrigeration and heat exchanger (20) comprises: a first refrigeration heat exchanger (201), the first refrigeration heat exchanger (201) being arranged between the compressor adjacent to the gas storage component (1) among the plurality of compressors and the gas storage component (1); and / or A second refrigeration heat exchanger (202) is provided between two adjacent compressors among the plurality of compressors.

9. The compressed air energy storage system according to any one of claims 1 to 4, characterized in that: The heat supply heat exchanger (30) comprises: a first heat supply heat exchanger (301), the first heat supply heat exchanger (301) being arranged between the air turbine (31) adjacent to the air storage component (1) among the plurality of air turbines (31) and the air storage component (1); and / or A second heat supply heat exchanger (302), wherein the second heat supply heat exchanger (302) is arranged between two adjacent air turbines (31) among the plurality of air turbines (31).

10. The compressed air energy storage system according to any one of claims 1 to 4, characterized in that: The compressed air energy storage system comprises: a first control valve (5), the first control valve (5) being arranged at the gas storage outlet to control the opening and closing of the gas storage outlet; and / or A second control valve (6) is provided at the gas storage inlet to control the opening and closing of the gas storage inlet.

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