Combined underwater energy storage system with air ejector

Abstract

The invention discloses a combined underwater energy storage system with an air ejector. The combined underwater energy storage system comprises an underwater compressed air energy storage subsystem, a deep sea concrete ball battery subsystem, a one-way valve and the air ejector. A working fluid inlet of the air ejector is connected with a gas outlet of an expansion machine of the underwater compressed air energy storage subsystem, and an outlet of the air ejector is directly connected with the external atmospheric environment; an outlet of the one-way valve is connected with an injection fluid inlet of the air injector through an exhaust pipeline, and an inlet of the one-way valve is connected with an exhaust port of the deep sea concrete ball battery subsystem. High-pressure air which is not used when an expansion machine of the underwater compressed air energy storage subsystem operates is used as working fluid of an air ejector to eject residual gas in a cabin of the deep sea concrete ball battery subsystem to form a vacuum environment, so that the deep sea concrete ball battery system obtains a higher vacuum degree in an energy storage stage; and the energy utilization efficiency and the energy storage efficiency are improved.

Description

Technical Field

[0001] This invention belongs to the field of underwater energy storage technology, specifically relating to a combined energy storage system that combines an underwater compressed air energy storage system with a deep-sea concrete sphere battery system. Background Technology

[0002] Energy storage technology refers to the technical means of storing energy through specific devices when there is a surplus of energy and releasing it when energy demand is high. This technology can solve the problem of mismatch between energy supply and demand in terms of time and intensity, and realize intertemporal energy dispatch and stable grid operation. Currently, there are two main large-scale energy storage technologies with application potential in underwater energy storage: underwater compressed air energy storage systems and deep-sea concrete sphere battery systems. Underwater compressed air energy storage systems achieve efficient energy storage and release by utilizing the constant pressure and temperature environment of the seabed; deep-sea concrete sphere battery systems are large-scale energy storage devices that utilize the pressure difference in the deep sea to store and release electrical energy. Its core principle is to use a pumped-storage mechanism to pump water to store energy when there is a surplus of power from the grid, and release energy through seawater pressure when there is a peak in electricity demand. However, in underwater compressed air energy storage systems, the potential energy of the air pressure at the expander outlet is not fully utilized, resulting in energy waste; in addition, due to the limitation of the vacuum level sucked in by the mechanical pump, deep-sea concrete sphere battery systems cannot achieve higher vacuum levels. Summary of the Invention

[0003] To address the aforementioned problems in existing technologies, this invention designs a combined underwater energy storage system with an air ejector. This system utilizes the high-pressure air that is not used during the operation of the expander in the underwater compressed air energy storage system to increase the vacuum level inside the deep-sea concrete sphere battery system, thereby improving energy storage efficiency.

[0004] To achieve the above objectives, the technical solution of the present invention is as follows: a combined underwater energy storage system with an air ejector, comprising an underwater compressed air energy storage subsystem, a deep-sea concrete sphere battery subsystem, a one-way valve, and an air ejector; The working fluid inlet of the air ejector is connected to the gas outlet of the expander of the underwater compressed air energy storage subsystem, and the outlet of the air ejector is directly connected to the external atmospheric environment; the outlet of the one-way valve is connected to the ejector fluid inlet of the air ejector via an exhaust pipe, and the inlet of the one-way valve is connected to the exhaust port of the deep-sea concrete sphere battery subsystem.

[0005] Further, the air ejector includes a working fluid channel, a nozzle, an ejector fluid channel, an intake chamber, a mixing chamber, a constant cross-section section, a diffuser chamber, and an outlet section; the outlet of the working fluid channel is connected to the nozzle inlet; the nozzle is a tapered and diffuser type nozzle, including a tapered section and a diffuser section, made of ceramic matrix composite material with a surface roughness of <0.1μm and a throat diameter of 0.5~1mm; the tapered section of the nozzle integrates a spiral guide groove with an angle of 4°~8°; the outlet of the ejector fluid channel is connected to the intake chamber; the outlet of the intake chamber is coaxially connected to the inlet of the mixing chamber; the diameter of the mixing chamber gradually decreases from the inlet to the outlet, and the outlet is connected to the inlet of the constant cross-section section; the ratio of the cross-sectional area of ​​the constant cross-section section to the cross-sectional area of ​​the nozzle throat is set to 3.5~6.5, and the outlet is connected to the inlet of the diffuser chamber; the diameter of the diffuser gradually increases from the inlet to the outlet, and the outlet is connected to the air ejector outlet section; the outlet section is directly connected to the atmospheric environment.

[0006] Furthermore, the underwater compressed air energy storage subsystem includes an electric motor, a compressor, an underwater air storage device, a regulating valve, an expander, and a generator a; the electric motor is driven by surplus electricity from the offshore power station; the compressor inlet is directly connected to the atmosphere, and the outlet is connected to the inlet of the underwater air storage device via an air transmission pipeline; the outlet of the underwater air storage device is connected to the inlet of the regulating valve via an air transmission pipeline; the outlet of the regulating valve is connected to the inlet of the expander via an air transmission pipeline; the output shaft of the expander is coaxially connected to the input shaft of the generator a; and the electricity generated by the generator a is connected to the power grid via a transmission line.

[0007] Furthermore, the offshore power station includes offshore wind power stations and photovoltaic power stations.

[0008] Furthermore, the deep-sea concrete sphere battery subsystem includes a concrete sphere, an internal chamber, a water pump, a drain valve, an inlet valve, a turbine, and a generator b. The concrete sphere is located on the seabed and is equipped with a drain outlet, an vent outlet, an inlet, and a wiring port. The drain outlet is connected to the outlet of the drain valve via a drain pipe, the vent outlet is connected to the inlet of a one-way valve via an vent pipe, the inlet is connected to the inlet of the inlet valve via an inlet pipe, and the wiring port is connected to the generator b via a power transmission line. The compartment is a cavity located inside a concrete sphere. Its inlet is connected to the inlet of the water inlet valve, and its outlet is connected to the inlet of the water pump and the inlet of the one-way valve, respectively. The outlet of the water pump is connected to the inlet of the drain valve. The drain valve is located on the outlet pipeline of the water pump, and its outlet is connected to the external seawater environment via a drain pipeline and a drain outlet. The outlet of the water inlet valve is connected to the inlet of the water turbine via a water inlet pipeline. The output shaft of the water turbine is coaxially connected to the input shaft of generator b. The electricity generated by generator b is connected to the power grid via transmission lines.

[0009] Furthermore, the water pump, drain valve, inlet valve, turbine, and generator b are directly installed inside the concrete sphere.

[0010] Compared with the prior art, the present invention has the following beneficial effects: This invention utilizes the high-pressure air that is not used during the operation of the expander of the underwater compressed air energy storage subsystem as the working fluid of the air ejector, which ejects the residual gas in the chamber of the deep-sea concrete sphere battery subsystem to form a vacuum environment. This allows the deep-sea concrete sphere battery system to obtain a higher vacuum degree during the energy storage phase, thereby improving its energy utilization efficiency and energy storage efficiency. Attached Figure Description

[0011] Figure 1 This is a schematic diagram of the system of the present invention.

[0012] Figure 2 This is a three-dimensional perspective view of the air ejector of the present invention.

[0013] Figure 3 for Figure 2 A magnified view of the nozzle at point I.

[0014] Figure 4 This is a front view of the air ejector of the present invention.

[0015] Figure 5 for Figure 4 AA cross-section view.

[0016] Figure 6 for Figure 5 A magnified sectional view of the nozzle at point II.

[0017] In the diagram: 1. Offshore power station; 2. Electric motor; 3. Compressor; 4. Underwater gas storage device; 5. Regulating valve; 6. Expander; 7. Generator a; 8. Power grid; 9. Check valve; 10. Air ejector; 11. Concrete sphere; 12. Inner chamber of the sphere; 13. Water pump; 14. Drain valve; 15. Inlet valve; 16. Water turbine; 17. Generator b; 18. Working fluid channel; 19. Nozzle; 20. Suction chamber; 21. Mixing chamber; 22. Constant cross section; 23. Diffuser chamber; 24. Outlet section; 25. Ejector fluid channel; 26. Nozzle converging section; 27. Nozzle diverging section; 28. Spiral guide channel. Detailed Implementation

[0018] The present invention will be further described below with reference to the accompanying drawings and embodiments. Figure 1-6 As shown, a combined underwater energy storage system with an air ejector includes an underwater compressed air energy storage subsystem, a deep-sea concrete sphere battery subsystem, a one-way valve 9, and an air ejector 10. The working fluid inlet of the air ejector 10 is connected to the gas outlet of the expander 6 of the underwater compressed air energy storage subsystem, and the outlet of the air ejector 10 is directly connected to the external atmospheric environment; the outlet of the one-way valve 9 is connected to the ejector fluid inlet of the air ejector 10 via an exhaust pipe, and the inlet of the one-way valve 9 is connected to the exhaust port of the deep-sea concrete ball battery subsystem.

[0019] Further, the air ejector 10 includes a working fluid channel 18, a nozzle 19, an ejector fluid channel 25, an intake chamber 20, a mixing chamber 21, a constant cross-section section 22, a diffuser chamber 23, and an outlet section 24; the outlet of the working fluid channel 18 is connected to the inlet of the nozzle 19; the nozzle 19 is a tapered and diffuser nozzle, including a tapered section 26 and a diffuser section 27, made of ceramic matrix composite material, with a surface roughness <0.1μm, and a throat diameter set to 0.5~1mm; the diffuser section 27 integrates a spiral guide groove 28, the angle of which is... The angle is set to 4°~8°; the outlet of the ejector fluid channel 25 is connected to the suction chamber 20; the outlet of the suction chamber 20 is coaxially connected to the inlet of the mixing chamber 21; the diameter of the mixing chamber 21 gradually decreases from the inlet to the outlet, and the outlet is connected to the inlet of the constant cross-section section 22; the ratio of the cross-sectional area of ​​the constant cross-section section 22 to the cross-sectional area of ​​the throat of the nozzle 19 is set to 3.5~6.5, and the outlet is connected to the inlet of the diffuser chamber 23; the diameter of the diffuser chamber 23 gradually increases from the inlet to the outlet, and the outlet is connected to the outlet section 24 of the air ejector 10; the outlet section 24 is directly connected to the atmospheric environment.

[0020] Furthermore, the underwater compressed air energy storage subsystem includes an electric motor 2, a compressor 3, an underwater air storage device 4, a regulating valve 5, an expander 6, and a generator a7; the electric motor 2 is driven by surplus electricity from the offshore power station 1; the compressor 3 has its inlet directly connected to the atmosphere and its outlet connected to the inlet of the underwater air storage device 4 via an air transmission pipeline; the outlet of the underwater air storage device 4 is connected to the inlet of the regulating valve 5 via an air transmission pipeline; the outlet of the regulating valve 5 is connected to the inlet of the expander 6 via an air transmission pipeline; the output shaft of the expander 6 is coaxially connected to the input shaft of the generator a7; and the electricity generated by the generator a7 is connected to the power grid 8 via a transmission line.

[0021] Furthermore, the offshore power station 1 includes an offshore wind power station and a photovoltaic power station.

[0022] Furthermore, the deep-sea concrete sphere battery subsystem includes a concrete sphere 11, an internal chamber 12, a water pump 13, a drain valve 14, an inlet valve 15, a turbine 16, and a generator b17. The concrete sphere 11 is located on the seabed and is equipped with a drain outlet, an vent outlet, an inlet, and a wiring port. The drain outlet is connected to the outlet of the drain valve 14 via a drain pipe, the vent outlet is connected to the inlet of the one-way valve 9 via an vent pipe, the inlet is connected to the inlet of the inlet valve 15 via an inlet pipe, and the wiring port is connected to the generator b17 via a power transmission line. The internal chamber... 12 is a cavity located inside the concrete sphere 11. Its inlet is connected to the inlet of the water inlet valve 15, and its outlet is connected to the inlet of the water pump 13 and the inlet of the one-way valve 9, respectively. The outlet of the water pump 13 is connected to the inlet of the drain valve 14. The drain valve 14 is located in the outlet pipeline of the water pump 13, and its outlet is connected to the external seawater environment via a drain pipeline and a drain outlet. The outlet of the water inlet valve 15 is connected to the inlet of the water turbine 16 via a water inlet pipeline. The output shaft of the water turbine 16 is coaxially connected to the input shaft of the generator b17. The electricity generated by the generator b17 is connected to the power grid 8 via a transmission line.

[0023] Furthermore, the water pump 13, drain valve 14, inlet valve 15, water turbine 16, and generator b17 are directly installed inside the concrete sphere 11.

[0024] The working process of this invention is as follows: The working process of this invention is mainly divided into an energy storage stage and an energy release stage.

[0025] In the energy storage phase of the underwater compressed air energy storage subsystem, surplus electricity from the offshore power station 1 supplies power to the electric motor 2, which drives the compressor 3 to draw in air from the atmosphere and compress it to generate high-pressure air. This high-pressure air is then stored in the underwater air storage device 4. During the inflation process, the underwater air storage device 4 expands, converting electrical energy into the pressure potential energy of the air.

[0026] During the energy release phase of the underwater compressed air energy storage subsystem, high-pressure air is discharged from the exhaust port of the underwater air storage device 4, and drives the expander 6 to do work through the regulating valve 5, which in turn drives the generator a7 to generate electricity, ultimately converting the pressure energy of the air into electrical energy and transmitting the generated electrical energy to the power grid 8.

[0027] During the energy storage phase of the deep-sea concrete sphere battery subsystem, surplus electricity from the offshore wind and solar power station 1 drives the water pump 13 to discharge seawater from the inner chamber 12 of the sphere into the external seawater environment through the drain valve 14. Subsequently, the one-way valve 9 is opened, using high-pressure air discharged from the expander 6 in the underwater compressed air energy storage subsystem as the driving air source. The residual gas in the inner chamber 12 is extracted through the air ejector 10. Specifically, the high-pressure air is accelerated to supersonic speed after passing through the Laval nozzle. After passing through the spiral guide channel of the expansion section, the airflow is forced to form a vortex, separating the core airflow from the boundary layer through centrifugal force, further increasing the central velocity, and forming a local low-pressure area at the nozzle expansion section outlet. This ejects the low-pressure residual gas, achieving a higher vacuum state within the inner chamber of the sphere. The ejected mixed gas is then pressurized and discharged into the atmosphere. In this process, electrical energy is converted into vacuum potential energy. During the energy release phase of the deep-sea concrete sphere battery subsystem, the inlet valve 15 is opened. Due to the huge pressure difference between the inner chamber 12 of the sphere and the external seawater environment, the external seawater is rapidly injected into the inner chamber 12 of the sphere through the inlet, which drives the water turbine 16 to rotate, thereby driving the generator b17 to generate electricity, and finally converting the vacuum potential energy into electrical energy, and transmitting the generated electrical energy to the power grid 8.

[0028] This invention is not limited to this embodiment. Any equivalent concept or modification within the technical scope disclosed in this invention shall be included within the protection scope of this invention.

Claims

1. A combined underwater energy storage system with air ejector, characterized by: The underwater compressed air energy storage subsystem, the deep-sea concrete ball battery subsystem, a one-way valve (9) and an air ejector (10); The working fluid inlet of the air ejector (10) is connected with the gas outlet of the expander (6) of the underwater compressed air energy storage subsystem, and the outlet of the air ejector (10) is directly connected with the external atmosphere; the outlet of the one-way valve (9) is connected with the ejecting fluid inlet of the air ejector (10) through an exhaust pipeline, and the inlet of the one-way valve (9) is connected with the exhaust port of the deep-sea concrete ball battery subsystem.

2. The hybrid underwater energy storage system with air ejector of claim 1, wherein: The air ejector (10) comprises a working fluid channel (18), a nozzle (19), an ejecting fluid channel (25), a suction chamber (20), a mixing chamber (21), an equal cross-section section (22), a diffuser chamber (23) and an outlet section (24); the outlet of the working fluid channel (18) is connected with the inlet of the nozzle (19); the nozzle (19) is a converging-diverging nozzle, comprising a nozzle converging section (26) and a nozzle diverging section (27), is made of ceramic matrix composite material, has a surface roughness of less than 0.1 μm, and has a throat diameter of 0.5-1 mm; the nozzle diverging section (27) is integrated with a spiral flow guide groove (28) having an angle of 4°-8°; the outlet of the ejecting fluid channel (25) is connected with the suction chamber (20); the outlet of the suction chamber (20) is coaxially connected with the inlet of the mixing chamber (21); the pipe diameter of the mixing chamber (21) gradually decreases from the inlet to the outlet, and the outlet is connected with the inlet of the equal cross-section section (22); the ratio of the cross-sectional area of the equal cross-section section (22) to the cross-sectional area of the throat of the nozzle (19) is set to be 3.5-6.5, and the outlet is connected with the inlet of the diffuser chamber (23); the pipe diameter of the diffuser chamber (23) gradually increases from the inlet to the outlet, and the outlet is connected with the outlet section (24) of the air ejector (10); and the outlet section (24) is directly connected with the atmosphere.

3. The hybrid underwater energy storage system with air ejector of claim 1, wherein: The underwater compressed air energy storage subsystem comprises an electric motor (2), a compressor (3), an underwater gas storage device (4), a regulating valve (5), an expander (6) and a generator a (7); the electric motor (2) is driven by the surplus power of a sea-based power station (1); the inlet of the compressor (3) is directly connected with the atmosphere, and the outlet is connected with the inlet of the underwater gas storage device (4) through a gas conveying pipeline; the outlet of the underwater gas storage device (4) is connected with the inlet of the regulating valve (5) through a gas conveying pipeline; the outlet of the regulating valve (5) is connected with the inlet of the expander (6) through a gas conveying pipeline; the output shaft of the expander (6) is coaxially connected with the input shaft of the generator a (7); and the electricity generated by the generator a (7) is fed into the power grid (8) through a power transmission line.

4. The hybrid underwater energy storage system with air ejector of claim 1, wherein: The sea-based power station (1) comprises a sea-based wind power station and a photovoltaic power station.

5. The hybrid underwater energy storage system with air ejector of claim 1, wherein: The deep-sea concrete ball battery subsystem comprises a concrete ball (11), an in-ball cabin (12), a water pumping pump (13), a water draining valve (14), a water inlet valve (15), a water turbine (16) and a generator b (17); the concrete ball (11) is located on the seabed and is provided with a water draining port, a gas exhausting port, a water inlet port and a wiring port; the water draining port is connected with the outlet of the water draining valve (14) through a water draining pipeline, the gas exhausting port is connected with the inlet of the one-way valve (9) through a gas exhausting pipeline, the water inlet port is connected with the inlet of the water inlet valve (15) through a water inlet pipeline, and the wiring port is connected with the generator b (17) through a power transmission line; the in-ball cabin (12) is a cavity inside the concrete ball (11), the inlet is connected with the inlet of the water inlet valve (15), and the outlet is connected with the inlet of the one-way valve (9) and the inlet of the water pumping pump (13) respectively; the outlet of the water pumping pump (13) is connected with the inlet of the water draining valve (14); the water draining valve (14) is arranged on the outlet pipeline of the water pumping pump (13), and the outlet is connected with the external seawater environment through the water draining pipeline and the water draining port; the outlet of the water inlet valve (15) is connected with the inlet of the water turbine (16) through the water inlet pipeline; the output shaft of the water turbine (16) is coaxially connected with the input shaft of the generator b (17); and the electricity generated by the generator b (17) is transmitted to the power grid (8) through the power transmission line.

6. The hybrid underwater energy storage system with air ejector of claim 1, wherein: The water pumping pump (13), the water draining valve (14), the water inlet valve (15), the water turbine (16) and the generator b (17) are directly installed inside the concrete ball (11).

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