An adjustable head pumped compressed air energy storage system and method of operation

Abstract

The present application relates to the technical field of physical energy storage, and particularly relates to a pumped compressed air energy storage system with adjustable water head and a running method. The technical scheme of the present application comprises a pumped storage power generation system, an adjustable pressure compressed air system and a heat storage system. The pumped storage power generation system comprises a lower reservoir, a reversible hydraulic generator unit and at least one gas-liquid co-container. The gas-liquid co-container is internally divided into a variable-volume water chamber and a gas chamber by a movable piston sealing device. The lower reservoir is connected with the reversible hydraulic generator unit and the water chamber of the gas-liquid co-container in sequence through a pipeline and a valve. During energy storage, the reversible hydraulic generator unit pressurizes and delivers the water in the lower reservoir to the water chamber. During energy release and power generation, the high-pressure water in the water chamber enters the reversible hydraulic generator unit to generate power and is discharged into the lower reservoir.

Description

Technical Field

[0001] This invention relates to the field of physical energy storage technology, and in particular to an adjustable head pumped compressed air energy storage system and its operation method. Background Technology

[0002] The installed capacity of new energy power generation such as wind power and photovoltaics has experienced explosive growth. However, as the proportion of wind power and photovoltaics in the overall power supply increases, the intermittency, randomness, and volatility of wind and photovoltaic power generation will bring huge impacts to the power grid, seriously affecting its safe and stable operation. Large-scale energy storage is an important way to establish a new power system and ensure the safe operation of the power grid. Pumped storage and compressed air energy storage technologies are relatively mature large-scale energy storage technologies. Pumped storage power stations may cause damage to natural resources, ecological environment, and landscape environment during construction and operation. Compressed air energy storage technology requires underground gas storage caverns and is limited by geographical conditions. To overcome geographical limitations, some scholars at home and abroad have proposed combining pumped storage and compressed air energy storage technologies to propose a pumped compressed air energy storage technology, but it has problems such as fluctuations in water pressure, fluctuations in gas pressure, large variations in turbine head, and the inability to adjust the unit output during energy release.

[0003] To address the aforementioned issues, this application proposes a pumped compressed air energy storage system with adjustable head, which enables continuous and stable unit output, controllable output, and solves the problem of head variation, providing a new approach for the promotion and application of pumped compressed air energy storage technology. Summary of the Invention

[0004] The purpose of this invention is to provide a novel energy storage technology that combines compressed air energy storage and pumped hydro storage power generation technology. This technology solves the problem of geographical limitations on pumped hydro storage and compressed air storage, and addresses the issue of pressure fluctuations in stored water and gas during energy storage. During energy release, it ensures that the water head at the turbine inlet is adjustable and controllable, thereby ensuring that the turbine generator set has peak shaving and frequency regulation functions, and achieving stable and adjustable power output.

[0005] The technical solution adopted in this invention is as follows: an adjustable head pumped compressed air energy storage system, comprising a pumped storage power generation system, an adjustable pressure compressed air system, and a thermal storage system;

[0006] The pumped-storage power generation system includes a lower reservoir, a reversible turbine generator set, and at least one gas-liquid co-containment tank. The gas-liquid co-containment tank is divided into a variable-volume water chamber and a gas chamber by a movable piston sealing device. The bottom of the lower reservoir is connected to the reversible turbine generator set and the water chamber of the gas-liquid co-containment tank in sequence through pipes and valves. During energy storage, the reversible turbine generator set pressurizes the water in the lower reservoir and delivers it to the water chamber. During energy release and power generation, the high-pressure water in the water chamber enters the reversible turbine generator set to generate electricity and is discharged into the lower reservoir.

[0007] The adjustable pressure compressed air system includes at least one gas-liquid co-containment tank, at least one air storage tank, and an air intake unit; the air chamber of the gas-liquid co-containment tank is connected to the air storage tank through a connecting pipe; during energy release and power generation, compressed air is discharged from the air storage tank to the gas-liquid co-containment tank; when the reversible hydro-turbine generator set needs to adjust its output, air is supplied to the air chamber through the air intake unit to adjust the air pressure inside the air chamber;

[0008] The aforementioned thermal storage system includes a cold water tank, a first circulating water pump, an air cooler, a hot water tank, a second circulating water pump, and an air heater, all connected in a circulating loop via pipes and valves. The air cooler and air heater are respectively connected to two branch pipes of the connecting pipe. During energy storage, air in the air chamber is compressed into the air storage tank, and the heat generated during the air compression process is transferred to the circulating water through the air cooler and stored in the hot water tank. During energy release and power generation, compressed air in the air storage tank enters the air chamber, and the heat from the hot water tank is transferred to the compressed air through the air heater.

[0009] Preferably, the air intake unit includes an air intake filter, an air compressor, and a pressure stabilizing tank connected in sequence, with the outlet of the pressure stabilizing tank connected to the connecting pipe via a valve.

[0010] Preferably, the at least one gas-liquid co-containment tank and the at least one gas storage tank have a maximum pressure tolerance of 4 MPa or greater.

[0011] Preferably, when the number of gas-liquid co-containment tanks and gas storage tanks is greater than or equal to two, the gas-liquid co-containment tanks are arranged at intervals with each other, and the gas storage tanks are arranged with each other, and all gas-liquid co-containment tanks and gas storage tanks are on the same horizontal plane.

[0012] Preferably, an exhaust valve is provided at the lowest water level of the gas-liquid co-containment tank.

[0013] The present invention also provides an operation method for an adjustable head pumped compressed air energy storage system, characterized by comprising the following steps:

[0014] (1) Preparations:

[0015] Before the system starts operating, water from the lower reservoir is injected into the water chamber of the gas-liquid co-containment tank through a reversible hydro-turbine generator set. Once the minimum water level is reached, water injection stops. Then, compressed air is injected into the air storage tank and the air chamber of the gas-liquid co-containment tank through the air intake unit, so that the air pressure in the air storage tank and the air chamber reaches the set value. At the same time, the first circulating water pump is started to transport cold water from the cold water storage tank to the hot water storage tank, and the compressed air is absorbed by the air cooler.

[0016] (2) Energy storage process:

[0017] During system energy storage, water from the lower reservoir is continuously injected into the water chamber via a reversible hydro-turbine generator set. As the piston sealing device moves upward within the gas-liquid co-containment tank, it continuously compresses the compressed air in the gas chamber. Compressed air is then injected into the gas storage tank through a connecting pipe. When the piston sealing device reaches the highest water level, water injection stops, and the air intake unit fine-tunes the gas storage pressure until the designed gas storage pressure value is reached. During the process of the compressed air flowing from the gas chamber to the gas storage tank, the first circulating water pump transports cold water from the cold water storage tank to the hot water storage tank, and the air cooler absorbs the heat from the compressed air.

[0018] (3) Energy release process:

[0019] When the system releases energy, the reversible hydro-turbine generator set is started. The high-pressure water stored in the water chamber drives the reversible hydro-turbine generator set to generate electricity, which is then discharged into the lower reservoir. At the same time, compressed air in the air storage tank continuously enters the air chamber. When the piston sealing device reaches the lowest water level, the energy release process ends.

[0020] (4) Adjusting the water head process:

[0021] When the system releases energy, the high-pressure water stored in the water chamber drives the reversible hydro-turbine generator unit to generate electricity, and then discharges into the lower reservoir. At the same time, compressed air in the air storage tank continuously enters the air chamber. As the piston sealing device continues to descend, the air pressure in the air chamber also continuously decreases, and the head of the water entering the reversible hydro-turbine generator unit continuously decreases. When the reversible hydro-turbine generator unit needs to increase or stabilize its output, compressed air is injected into the air chamber through the air intake unit to maintain or increase the air pressure in the air chamber, thereby adjusting the head.

[0022] Repeat steps (2), (3), and (4) above to achieve the cyclic storage and release of electrical energy and heat;

[0023] (5) Exhaust process:

[0024] When the piston sealing device is at the lowest water level in the gas-liquid co-containment tank, open the vent valve periodically to release the air accumulated in the water chamber.

[0025] The beneficial effects of this invention are:

[0026] 1. This energy storage system has an energy storage efficiency of over 70%;

[0027] 2. It can stabilize gas storage pressure and water storage pressure during energy storage and release processes;

[0028] 3. It can ensure stable and adjustable power output of the unit during the energy release process, and can provide peak shaving, frequency regulation and other services for the power grid;

[0029] 4. This energy storage system does not consume fossil fuels, does not cause environmental pollution, and is not limited by geographical conditions;

[0030] 5. The excess heat generated during system operation can be used to provide comprehensive energy supply, and industrial waste heat can be recovered and reused. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of an adjustable head pumped compressed air energy storage system according to Embodiment 1 of the present invention.

[0032] Figure 2 This is a schematic diagram of an adjustable head pumped compressed air energy storage system according to Embodiment 2 of the present invention.

[0033] Reference numerals: 1. Lower reservoir; 2. Reversible hydro-turbine generator set; 3. Gas-liquid co-containment tank; 4. Piston sealing device; 5. Air cooler; 6. Air storage tank; 7. Air heater; 8. Air intake filter device; 9. Air compressor; 10. Pressure stabilizing tank; 11. Cold water storage tank; 12. Hot water storage tank; 13. First circulating water pump; 14. Second circulating water pump; 15. First isolation valve; 16. Second isolation valve; 17. Third isolation valve; 18. First check valve; 19. Fourth isolation valve; 20. Pneumatic regulating valve; 21. Fifth isolation valve; 22. Sixth isolation valve; 23. Second check valve; 24. Seventh isolation valve; 25. Third check valve; 26. Exhaust valve. Detailed Implementation

[0034] To enable those skilled in the art to more clearly understand the purpose, technical solution and advantages of the present invention, the present invention will be further described below in conjunction with the accompanying drawings and embodiments, but the present invention is not limited to the following embodiments.

[0035] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "upper", "lower", "inner", "outer", "front end", "rear end", "both ends", "one end", "the other end", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation.

[0036] It should also be noted that, unless otherwise explicitly specified and limited, the terms "setup" and "connection" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to the internal connection of two components. Furthermore, the terms "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0037] Example 1

[0038] like Figure 1As shown, this embodiment 1 provides an adjustable head pumped compressed air energy storage system, including a pumped storage power generation system, an adjustable pressure compressed air system, and a thermal storage system.

[0039] like Figure 1 As shown, the pumped-storage power generation system includes a lower reservoir 1, a reversible turbine generator set 2, and a gas-liquid co-containment tank 3. The gas-liquid co-containment tank 3 is internally divided into a variable-volume water chamber and a gas chamber by a vertically movable piston sealing device 4. An exhaust valve 26 is installed at the lowest water level of the gas-liquid co-containment tank 3. The bottom of the lower reservoir 1 is connected to the water chambers of the reversible turbine generator set 2 and the gas-liquid co-containment tank 3 via pipelines. A first isolation valve 15 is installed at both the front and rear of the reversible turbine generator set 2. During energy storage, the reversible turbine generator set 2 pressurizes and transports water from the lower reservoir 1 to the water chamber of the gas-liquid co-containment tank 3; during energy release and power generation, the high-pressure water in the water chamber enters the reversible turbine generator set 2 to generate electricity and is discharged back into the lower reservoir 1.

[0040] like Figure 1 As shown, the adjustable pressure compressed air system includes the gas-liquid co-containment tank 3, the air storage tank 6, and the air intake unit. The maximum pressure withstand value of the gas-liquid co-containment tank 3 and the air storage tank 6 should be greater than or equal to 4 MPa. The air chamber of the gas-liquid co-containment tank 3 and the air storage tank 6 are connected by a connecting pipe at the top. A second isolation valve 16 is provided at the outlet of the air chamber on the connecting pipe. The air intake unit includes an air intake filter device 8, an air compressor 9, a pressure stabilizing tank 10, a first check valve 18, a fourth isolation valve 19, a pneumatic regulating valve 20, and the fourth isolation valve 19 connected in sequence through a pipe. The fourth isolation valve 19 on the rear side of the pneumatic regulating valve 20 is connected to the connecting pipe on the rear side of the second isolation valve 16. The air storage tank 6 is used to store compressed air. When the pumped-storage power generation system releases energy to generate electricity, the compressed air is discharged from the air storage tank 6 to the air chamber of the gas-liquid co-containment tank 3. When the output of the reversible hydro-turbine generator unit 2 needs to be adjusted, air is supplied to the air chamber of the gas-liquid co-containment tank 3 through the pressure stabilizing tank 10 and the air compressor 9 to adjust the air pressure in the air chamber, thereby realizing the function of adjusting the head of the reversible hydro-turbine generator unit. The piston sealing device 4 isolates compressed air and high-pressure water, reducing air loss and air moisture content.

[0041] like Figure 1As shown, the thermal storage system includes a cold water tank 11, a sixth isolation valve 22, a first circulating water pump 13, a second check valve 23, a sixth isolation valve 22, an air cooler 5, a sixth isolation valve 22, a hot water tank 12, a seventh isolation valve 24, a second circulating water pump 14, a third check valve 25, a seventh isolation valve 24, an air heater 7, and a seventh isolation valve 24, all connected in a circulating loop via pipes. The middle section of the connecting pipe splits into two branch pipes, with the air cooler 5 and air heater 7 connected to these branch pipes respectively. The air cooler 5 has a third isolation valve 17 at both ends, and the air heater 7 has a fifth isolation valve 21 at both ends. It should also be noted that both the air cooler 5 and the air heater 7 have internal and external pipes. Generally, the circulating water of the thermal storage system flows through one pipe, while the compressed air of the adjustable pressure compressed air system flows through the other pipe. During energy storage in the pumped compressed air energy storage system, air in the air chamber is compressed into the air storage tank 6. The heat from the air compression process is exchanged with the circulating water through the air cooler 5 and stored in the hot water storage tank 12. During energy release in the pumped compressed air energy storage system, compressed air in the air storage tank 6 enters the air chamber, and the heat from the hot water storage tank 12 is transferred to the compressed air through the air heater 7.

[0042] This embodiment 1 also provides an operation method for an adjustable head pumped compressed air energy storage system. Based on the above-mentioned adjustable head pumped compressed air energy storage system, the operation method includes the following steps:

[0043] (1) Preparations:

[0044] Before the system starts operating, water from the lower reservoir 1 is first injected into the water chamber of the gas-liquid co-containment tank 3 via the reversible hydro-turbine generator set 2 by opening the first isolation valve 15. After reaching the minimum water level, the water injection is stopped. Then, compressed air is injected into the air chambers of the air storage tank 6 and the gas-liquid co-containment tank 3 by opening the air compressor 9, the fourth isolation valve 19, the pneumatic regulating valve 20, the second isolation valve 16, and the third isolation valve 17, so that the air pressure in the air storage tank 6 and the air chamber reaches the set value of 2MPa. At the same time, the first circulating water pump 13 is started to transport the cold water in the cold water storage tank 11 to the hot water storage tank 12, and the compressed air absorbs heat through the air cooler 5.

[0045] (2) Energy storage process:

[0046] During system energy storage, water from the lower reservoir 1 is continuously injected into the water chamber of the gas-liquid co-containment tank 3 via the reversible hydro-turbine generator set 2. Water injection stops when the piston sealing device 4 reaches the highest water level. Simultaneously, as the piston sealing device 4 moves upward within the gas-liquid co-containment tank 3, compressed air from the gas chamber is continuously injected into the gas storage tank 6 through the top connecting pipe. The final gas pressure in the gas storage tank 6 reaches approximately 4 MPa. The final gas storage pressure can be fine-tuned by the air compressor 9 and the pressure stabilizing tank 10 to achieve the designed gas storage pressure value. During the flow of compressed air from the gas chamber to the gas storage tank 6, the sixth isolation valve 22 and the second check valve 23 are opened. The first circulating water pump 13 then transports cold water from the cold water storage tank 11 to the hot water storage tank 12, and the air cooler 5 absorbs the heat from the compressed air.

[0047] (3) Energy release process:

[0048] When the system releases energy, isolation valve 17 is first closed and isolation valve 21 is opened. Then, the reversible hydro-turbine generator set 2 is started. Compressed air from the air storage tank 6 continuously enters the air chamber of the gas-liquid co-containment tank 3. The approximately 4MPa high-pressure water stored in the water chamber drives the reversible hydro-turbine generator set 2 to generate electricity, which is then discharged into the lower reservoir 1. During the process of compressed air from the air storage tank 6 entering the air chamber, the seventh isolation valve 24 and the third check valve 25 are opened. The second circulating water pump 14 transports the hot water from the hot water storage tank 12 to the cold water storage tank 11. The heat is transferred to the compressed air through the air heater 7. Finally, when the piston sealing device 4 reaches the lowest water level, the energy release process ends. At this time, the air pressure in the gas-liquid co-containment tank 3 and the air storage tank 6 is approximately 2MPa.

[0049] (4) Adjusting the water head process:

[0050] When the system releases energy, the approximately 4MPa high-pressure water stored in the gas-liquid co-containment tank 3 drives the reversible hydro-turbine generator unit 2 to generate electricity, and then discharges into the lower reservoir 1. Simultaneously, compressed air from the air storage tank 6 continuously enters the air chamber of the gas-liquid co-containment tank 3. As the piston sealing device 4 moves downward, the air pressure in the air chamber continuously decreases, causing the head of the water entering the reversible hydro-turbine generator unit 2 to also continuously decrease. When the reversible hydro-turbine generator unit 2 needs to increase or stabilize its output, compressed air can be injected into the air chamber of the gas-liquid co-containment tank 3 through the pressure stabilizing tank 10 and the pneumatic regulating valve 20, or by further opening the air compressor 9, to maintain or increase the air pressure in the air chamber, thereby adjusting the head.

[0051] Repeating steps (2), (3), and (4) above will allow for the cyclical storage and release of electrical energy and heat.

[0052] (5) Exhaust process:

[0053] After prolonged system operation, air may accumulate in the water chamber of the gas-liquid co-containment tank, potentially causing cavitation in the reversible hydro-generator unit 2 and reducing the water storage capacity of the gas-liquid co-containment tank 3. To promptly remove this air, an air vent valve 26 is installed at the lowest water level of the gas-liquid co-containment tank 3. When the piston sealing device 4 is at the lowest water level of the gas-liquid co-containment tank 3, the air vent valve 26 is periodically opened to release the accumulated air.

[0054] Example 2

[0055] like Figure 2 As shown, the difference between this embodiment 2 and embodiment 1 is that this embodiment 2 is provided with two gas-liquid co-containment tanks 3 and two gas storage tanks 6. The gas-liquid co-containment tanks 3 and the gas storage tanks 6 are arranged at intervals, and all gas-liquid co-containment tanks 3 and gas storage tanks 6 are on the same horizontal plane.

[0056] Appropriately increasing the number of gas-liquid co-containment tanks 3 and gas storage tanks 6 can improve the overall energy storage, heat storage and system efficiency of the system.

[0057] Based on the description and accompanying drawings of this invention, those skilled in the art can easily manufacture or use the adjustable head pumped compressed air energy storage system and its operating method as described in this invention, and can achieve the positive effects described in this invention.

[0058] The above description is merely a preferred embodiment of the present invention. For those skilled in the art, the present invention can have various modifications and variations. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A pumped compressed air energy storage system with adjustable water head, characterized in that: The system comprises a pumped storage power generation system, an adjustable pressure compressed air system, and a heat storage system. The pumped storage power generation system comprises a lower reservoir (1), a reversible hydraulic generator set (2), and at least one gas-liquid co-container (3). The gas-liquid co-container (3) is divided into a variable-volume water chamber and a gas chamber by a movable piston sealing device (4). The lower reservoir (1) is connected to the reversible hydraulic generator set (2) and the water chamber of the gas-liquid co-container (3) in sequence through a pipeline and a valve. During energy storage, the reversible hydraulic generator set (2) pressurizes and delivers the water in the lower reservoir (1) to the water chamber. During energy release and power generation, the high-pressure water in the water chamber enters the reversible hydraulic generator set (2) to generate electricity and is discharged into the lower reservoir (1). The adjustable pressure compressed air system comprises the at least one gas-liquid co-container (3), at least one gas storage tank (6), and an air intake unit. The gas chamber of the gas-liquid co-container (3) is connected to the gas storage tank (6) through a communication pipe. During energy release and power generation, compressed air is discharged from the gas storage tank (6) to the gas-liquid co-container (3). When the reversible hydraulic generator set (2) needs to adjust the output, the air chamber is inflated through the air intake unit to adjust the air pressure in the air chamber. The heat storage system comprises a cold water storage tank (11), a first circulating water pump (13), an air cooler (5), a heat storage water tank (12), a second circulating water pump (14), and an air heater (7), which are connected in sequence through a pipeline and a valve to form a circulating loop. The air cooler (5) and the air heater (7) are connected to two branches of the communication pipe, respectively. During energy storage, the air in the gas chamber is compressed into the gas storage tank (6), and the heat generated during the air compression is exchanged to the circulating water through the air cooler (5) and stored in the heat storage water tank (12). During energy release and power generation, the compressed air in the gas storage tank (6) enters the gas chamber, and the heat in the heat storage water tank (12) is transferred to the compressed air through the air heater (7). An exhaust valve (26) is arranged at the lowest water level of the gas-liquid co-container (3).

2. The adjustable head hydro-pumped compressed air energy storage system of claim 1, wherein: The air intake unit comprises an air intake filter device (8), an air compressor (9), and a pressure stabilizing tank (10) connected in sequence. The outlet of the pressure stabilizing tank (10) is connected to the communication pipe through a valve.

3. The adjustable head hydro-pumped compressed air energy storage system of claim 2, wherein: The maximum pressure bearing value of the at least one gas-liquid co-container (3) and the at least one gas storage tank (6) is greater than or equal to 4 MPa.

4. The adjustable head hydro-pumped compressed air energy storage system of claim 3, wherein: When the number of the gas-liquid co-containers (3) and the gas storage tanks (6) is greater than or equal to two, the gas-liquid co-containers (3) and the gas-liquid co-containers (3), and the gas storage tanks (6) and the gas-liquid co-containers (3) are arranged at intervals, and all the gas-liquid co-containers (3) and the gas storage tanks (6) are at the same level.

5. A method of operating a pumped hydro compressed air energy storage system of variable head as claimed in any one of claims 1 to 4, characterised in that, The method comprises the following steps: (1) Preparation work: Before the system runs, the water in the lower reservoir (1) is injected into the water chamber of the gas-liquid co-container (3) through the reversible hydraulic generator set (2), and the injection is stopped when the water reaches the lowest water level; then compressed air is injected into the air chamber in the gas-liquid co-container (3) and the gas storage tank (6) through the air inlet unit, so that the gas pressure in the gas storage tank (6) and the air chamber reaches the set value; at the same time, the first circulating water pump (13) is started to deliver the cold water in the cold water storage tank (11) to the hot water storage tank (12), and the air cooler (5) absorbs the heat of the compressed air. (2) Energy storage process: When the system stores energy, the water in the lower reservoir (1) is continuously injected into the water chamber through the reversible hydraulic generator set (2), and the piston sealing device (4) is continuously compressed in the gas-liquid co-container (3) when it moves upwards, and the compressed air in the air chamber is injected into the gas storage tank (6) through the connecting pipe, and when the piston sealing device (4) reaches the highest water level point, the water injection is stopped, and the air pressure is adjusted by the air inlet unit, and finally the design gas storage pressure value is reached; during the process of the compressed air in the air chamber flowing to the gas storage tank (6), the first circulating water pump (13) delivers the cold water in the cold water storage tank (11) to the hot water storage tank (12), and the air cooler (5) absorbs the heat of the compressed air. (3) Energy release process: When the system releases energy, the reversible hydraulic generator set (2) is started, and the high-pressure water stored in the water chamber drives the reversible hydraulic generator set (2) to generate electricity and then is discharged into the lower reservoir (1); at the same time, the compressed air in the gas storage tank (6) continuously enters the air chamber, and when the piston sealing device (4) reaches the lowest water level, the energy release process is completed. (4) Adjusting the water head process: When the system releases energy, the high-pressure water stored in the water chamber drives the reversible hydraulic generator set (2) to generate electricity and then is discharged into the lower reservoir (1); at the same time, the compressed air in the gas storage tank (6) continuously enters the air chamber, and as the piston sealing device (4) continuously descends, the air pressure in the air chamber also continuously decreases, and the water head entering the reversible hydraulic generator set (2) continuously decreases; when the reversible hydraulic generator set (2) needs to increase power or stabilize power, compressed air is injected into the air chamber through the air inlet unit to maintain or increase the air pressure in the air chamber, thereby adjusting the water head. Repeat steps (2), (3), and (4) above to achieve the cyclic storage and release of electrical energy and heat.

6. The method of operating of claim 5, wherein, It also includes the following steps: (5) Exhaust process: When the piston sealing device (4) is at the lowest water level of the gas-liquid co-container (3), the exhaust valve (26) is opened periodically to exhaust the air accumulated in the water chamber.

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