Underwater air storage device for compressed air gravity hybrid energy storage

Abstract

The invention relates to an underwater air storage device for compressed air gravity mixed energy storage, and belongs to the technical field of mixed energy storage devices, the underwater air storage device comprises a compressed air energy storage system, the compressed air energy storage system comprises an air conveying pipeline extending in the vertical direction, and the air conveying pipeline is connected with an air storage bag; the gravity energy storage system comprises a first mooring rope and a heavy object, and the heavy object is connected to the exterior of the air storage bag through the first mooring rope; wherein the gravity energy storage system is installed on the bearing frame, a pile foundation is arranged at the bottom of the bearing frame, the pile foundation is fixed to the underwater plane, the gravity energy storage system is arranged underwater, an air conveying pipeline of the compressed air energy storage system extends into water, and an air storage bag of the compressed air energy storage system is arranged underwater. The hybrid energy storage device is designed, the hybrid energy storage effect is generated by effectively utilizing underwater buoyancy changes, and an innovative technical route of compressed air and gravity hybrid energy storage is provided.

Description

Technical Field

[0001] The present invention belongs to the technical field of hybrid energy storage devices, and in particular relates to an underwater air storage device for compressed air gravity hybrid energy storage. Background Art

[0002] Compressed air energy storage is a physical energy storage technology with the characteristics of large-scale, low-cost, high safety, clean and pollution-free. It is mainly composed of a compressor, an expander, and a gas storage system. The technical principle is that when electricity consumption is low, the compressor is driven by an electric motor to compress the air and store it in the gas storage system; when electricity consumption is high, the high-pressure air is released into the expander to do work and drive the generator to generate electricity. The gas storage methods mainly include pressure vessels such as gas storage tanks, underground caves such as natural salt caves, artificial underground gas storage reservoirs, and underwater gas storage bags. Among them, the underwater gas storage bag has flexible site selection, high gas storage volume utilization, and better air safety. Canada's Hydrostor has built a 2.2MW demonstration system. The underwater gas storage bag is located 80 meters underwater and can effectively store gas for 3 hours. The American Brayton Company has also built a 6.6MW demonstration system. However, the existing underwater gas storage bag technology is relatively simple, and the underwater gas storage bag is fixed or semi-fixed in a certain position. The buoyancy changes caused by the periodic inflation and deflation of the underwater air storage bag are not fully used to store energy, and the periodic buoyancy changes also affect the fixation stability and durability of the air bag.

[0003] Gravity energy storage is a physical energy storage that is competitive in both environmental protection and economy. The weight is raised and lowered based on the height difference to realize the storage and release of gravitational potential energy, and then the electric generator and transmission system are coordinated to realize charging and discharging. Compressed air energy storage and gravity energy storage can be combined in the gas storage device to form a hybrid energy storage system. The existing technical route is to set a sealed piston that can move up and down on the top of the gas storage chamber, and place a heavy object on the piston, so as to realize the linkage between charging and discharging of air and the up and down movement of the heavy object, forming the synchronous charging and release of compressed air energy storage and gravity energy storage. However, the existing gravity energy storage technology adopts three forms, namely mountain drop system, underground shaft, and ground structure, which all need to occupy land and do not make full use of underwater space. Moreover, underwater gravity energy storage is safer, and it is more convenient to link with pumped storage and water-light complementarity.

[0004] At present, compressed air energy storage and gravity energy storage technologies are relatively mature and have been widely used in engineering. The underwater air storage bag technology in the compressed air energy storage system is still in the stage of technical improvement and preliminary application. There are about 10 related Chinese patents, and the applicants include Shenzhen Sino Verne Energy Co., Ltd. (CN110332462B), Zhejiang University (CN111911389A), Harbin Institute of Technology (CN113482889A), Xi'an Jiaotong University (CN107893735B), South China University of Technology (CN214464803U), etc. The existing patents use fixed underwater air storage bags, or semi-fixed underwater air storage bags such as cables and springs. The existing patents have not fully utilized the energy changes brought about by the buoyancy changes of underwater air storage bags. Patent CN107893735B uses wave energy to assist compressed air for underwater air storage bags, but has not yet achieved the effect of hybrid energy storage. The hybrid energy storage of compressed air and gravity is still in the research and development stage, and there is no mature engineering application. The existing technologies are all experimentally studied around the route of setting weights on the piston of the rigid air storage chamber. The existing hybrid energy storage of compressed air and gravity is relatively limited, mostly using weights and rigid wall spaces with pistons to form hybrid energy storage devices. There is no hybrid energy storage design for flexible wall air storage devices without pistons such as air storage bags, nor is there a hybrid energy storage design that utilizes changes in underwater buoyancy. Summary of the invention

[0005] In response to the above problems, the present invention improves the adjustment flexibility of the position parameters of the underwater air storage bag, thereby improving the comprehensive efficiency and variable operating conditions of the compressed air energy storage system, and is expected to promote the application of underwater gravity energy storage devices, improve safety and save land; the buoyancy change of the underwater air storage bag is used to drive the movement of heavy objects, thereby realizing a new hybrid energy storage route of compressed air and gravity.

[0006] In order to overcome the problems existing in the prior art, the present invention provides the following technical solutions:

[0007] An underwater air storage device for compressed air gravity mixed energy storage, comprising:

[0008] A compressed air energy storage system, the compressed air energy storage system comprising a gas pipeline extending in a vertical direction, the gas pipeline being connected to a gas storage bag;

[0009] A gravity energy storage system, the gravity energy storage system comprising a first cable and a weight, the weight being connected to the outside of the gas storage bag via the first cable;

[0010] Among them, the gravity energy storage system is installed on a load-bearing frame, a pile foundation is provided at the bottom of the load-bearing frame, the pile foundation is fixed on the bottom plane of the water, the gravity energy storage system is arranged underwater, the air transmission pipeline of the compressed air energy storage system extends into the water, and the air storage bag of the compressed air energy storage system is arranged underwater.

[0011] Furthermore, the compressed air energy storage system includes an electric motor, a compressor, and an air storage buffer chamber, wherein the electric motor is connected to the compressor, the compressor is connected to the air storage buffer chamber, and the air storage buffer chamber is connected to a gas pipeline.

[0012] Furthermore, the compressed air energy storage system includes an expander and a first generator, the air storage buffer chamber is connected to the expander, and the expander is connected to the first generator.

[0013] Furthermore, a valve is installed on the connecting pipeline between the compressor and the gas storage buffer chamber, and a valve is also installed on the connecting pipeline between the gas storage buffer chamber and the expander.

[0014] Furthermore, the gas transmission pipeline is made of a flexible material, and the gas storage bag is made of a flexible material.

[0015] Furthermore, the gravity energy storage system includes a pulley block and a pulley rope winding machine fixed on the load-bearing frame, the pulley rope winding machine is provided with a second cable, and the second cable is connected to the weight through the pulley block.

[0016] Furthermore, the gravity energy storage system also includes an upper limit device and a lower limit device, the upper limit device is installed at the upper end of the load-bearing frame, the lower limit device is installed at the lower end of the load-bearing frame, and the first cable and the second cable pass through the upper limit device.

[0017] Furthermore, the weight is limited between the upper limit device and the lower limit device, and is configured to be able to move linearly by being pulled by the first cable and the second cable.

[0018] Furthermore, a second generator and a gearbox are fixed on the pile foundation, and the second generator is connected to the gearbox.

[0019] Furthermore, a transmission belt is installed on the pulley rope winding machine, and the transmission belt connects the pulley shaft and the gearbox of the pulley rope winding machine.

[0020] Beneficial effects of the present invention: The present invention makes full use of the volume changes and buoyancy changes of the underwater air storage bag, flexibly adjusts the position, volume, pressure and other parameters of the air storage bag, promotes the durability of the air storage bag, and better serves compressed air energy storage; effectively utilizes underwater space to deploy gravity energy storage, improves safety and the feasibility of hybrid energy storage; designs a hybrid energy storage device for flexible wall air storage devices such as air storage bags that are difficult to design pistons, and effectively utilizes underwater buoyancy changes to produce a hybrid energy storage effect, providing an innovative technical route for compressed air-gravity hybrid energy storage.

[0021] Other features and advantages of the present invention will be described in the following description, and partly become obvious from the description, or be understood by implementing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures pointed out in the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0023] Figure 1 A schematic structural diagram of the gas release and energy generation process of an underwater gas storage device for compressed air gravity hybrid energy storage according to an embodiment of the present invention is shown;

[0024] Figure 2 A schematic diagram of the charging and energy storage process of an underwater air storage device for compressed air gravity hybrid energy storage according to an embodiment of the present invention is shown;

[0025] Figure 3 A schematic structural diagram of a compressed air energy storage system according to an embodiment of the present invention is shown.

[0026] In the picture

[0027] 1-motor, 101-valve, 2-compressor, 201-pile foundation, 202-load-bearing frame, 3-expander, 4-first generator, 5-gas storage buffer chamber, 6-gas storage bag, 7-gas transmission pipeline, 8-weight, 9-lower limit device, 10-pulley block, 11-first cable, 12-second cable, 13-pulley winder, 14-transmission belt, 15-gearbox, 16-second generator, 17-upper limit device. DETAILED DESCRIPTION

[0028] In the following, only some exemplary embodiments are briefly described. As those skilled in the art will appreciate, the described embodiments may be modified in various ways without departing from the spirit or scope of the present invention. Therefore, the drawings and descriptions are considered to be exemplary and non-restrictive in nature.

[0029] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] It should be noted that the terms "first", "second" etc. in the present application are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequential order. It should be understood that the data used in this way can be interchanged in appropriate circumstances, so that the embodiments of the present application described here. In the present application, the orientation or positional relationship indicated by the terms "upper", "lower", "left", "right", "front", "back", "top", "bottom", "inside", "outside", "middle", "vertical", "horizontal", "lateral", "longitudinal" etc. are based on the orientation or positional relationship shown in the accompanying drawings.

[0031] The embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0032] The embodiment of the present application is an underwater gas storage device for compressed air gravity hybrid energy storage. The entire device is fixed to the bottom of the water by pile foundation 201, and a protruding load-bearing frame 202 provides support for the device. Conventional operation includes two processes: (A) deflation, energy release, and power generation, and (B) inflation, energy storage, and power storage, realizing the charging and discharging of the hybrid energy storage system. The device includes a compressed air energy storage system, which includes a gas pipeline 7 extending in a vertical direction, and the gas pipeline 7 is connected to a gas storage bag 6; a gravity energy storage system, which includes a first cable 11 and a weight 8, and the weight 8 is connected to the outside of the gas storage bag 6 through the first cable 11; the gravity energy storage system is installed on a load-bearing frame 202, and a pile foundation 201 is provided at the bottom of the load-bearing frame 202, and the pile foundation 201 is fixed on the bottom plane of the water, the gravity energy storage system is arranged underwater, the gas pipeline 7 of the compressed air energy storage system extends into the water, and the gas storage bag 6 of the compressed air energy storage system is arranged underwater.

[0033] like Figure 3, compressed air energy storage system, the compressed air energy storage system includes a motor 1, a compressor 2, and a gas storage buffer chamber 5, the motor 1 is connected to the compressor 2, the compressor 2 is connected to the gas storage buffer chamber 5, and the gas storage buffer chamber 5 is connected to the gas pipeline 7. The compressed air energy storage system includes an expander 3 and a first generator 4, the gas storage buffer chamber 5 is connected to the expander 3, and the expander 3 is connected to the first generator 4. A valve 101 is installed on the connecting pipeline between the compressor 2 and the gas storage buffer chamber 5, and a valve 101 is also installed on the connecting pipeline between the gas storage buffer chamber 5 and the expander 3. During the A gas release and energy generation process, the valve 101 on the connecting pipeline between the motor 1, the compressor 2 and the gas storage buffer chamber 5 is closed, and the valve 101 on the connecting pipeline between the gas storage buffer chamber 5 and the expander 3 is opened; during the B gas charging and energy storage process, the valve 101 on the connecting pipeline between the motor 1, the compressor 2 and the gas storage buffer chamber 5 is opened, and the valve 101 on the connecting pipeline between the gas storage buffer chamber 5 and the expander 3 is closed.

[0034] The gas pipeline 7 is made of flexible material, and the gas storage bag 6 is made of flexible material. The design of the gas storage bag 6 and the gas pipeline 7 uses existing materials, and the gas storage bag 6 is a flexible, expandable or foldable balloon, and the specific material selection of this part is not repeated.

[0035] The gravity energy storage system includes a pulley block 10 and a pulley rope reel 13 fixed on the load-bearing frame 202, and the pulley rope reel 13 is provided with a second cable 12, and the second cable 12 is connected to the weight 8 through the pulley block 10. The gravity energy storage system also includes an upper limit device 17 and a lower limit device 9, the upper limit device 17 is installed at the upper end of the load-bearing frame 202, and the lower limit device 9 is installed at the lower end of the load-bearing frame 202, and the first cable 11 and the second cable 12 pass through the upper limit device 17.

[0036] The weight 8 is limited between the upper limit device 17 and the lower limit device 9 , and is configured to be able to move linearly by being pulled by the first cable 11 and the second cable 12 .

[0037] The second generator 16 and the gearbox 15 are fixed on the pile foundation 201. The second generator 16 is connected to the gearbox 15. The pulley winding machine 13 is provided with a transmission belt 14. The transmission belt 14 connects the pulley shaft of the pulley winding machine 13 and the gearbox 15.

[0038] like Figure 1 , is the A gas release and energy generation process of the underwater gas storage device with compressed air gravity mixed energy storage:

[0039] The underwater air storage bag 6 releases gas, which is transported to the air storage buffer chamber 5 through the flexible air transmission pipeline 7 and then to the expander 3 of the compressed air energy storage system, driving the expander 3 to work and driving the first generator 4 to generate electricity. Due to the deflation, the underwater air storage bag 6 shrinks in volume and reduces its buoyancy under the action of water pressure, and is dragged downward by the weight 8 and sinks until the weight 8 reaches the lower limit device 9;

[0040] At the same time, the weight 8 drags the first cable 11, drives the pulley block 10 and the second cable 12, and drives the pulley winder 13 to move. The pulley shaft of the pulley winder 13 drives the gearbox 15 to rotate through the transmission belt 14, and drives the underwater second generator 16 to generate electricity, thereby converting the gravitational potential energy into electrical energy. The power generation of compressed air energy storage and the power generation of gravity energy storage can be mixed and complemented to provide electricity for peak power consumption.

[0041] like Figure 2 , is the B inflation energy storage process of the underwater gas storage device with compressed air gravity mixed energy storage:

[0042] During the low electricity consumption period, the excess electric energy is transmitted to the motor 1, and the motor 1 drives the compressor 2 of the compressed air energy storage system, compressing the high-pressure air into the air storage buffer chamber 5, and then filling it into the underwater air storage bag 6 through the flexible air transmission pipeline 7. As the underwater air storage bag 6 is inflated, its volume expands and its buoyancy increases, dragging the weight 8 upward until the weight 8 reaches the upper limit device 17;

[0043] When the weight 8 rises, it drives the first cable 11, the second cable 12 and the pulley block 10 to move, and the second cable 12 is retracted by the pulley winding machine 13 with a clockwork device. At this time, the gearbox 15 is switched to neutral, so the transmission belt 14 is idling, and the gearbox 15 and the second generator 16 are not working. In this process, the excess electrical energy during the low electricity consumption period is converted into the potential energy of high-pressure air and the potential energy of the weight, which is effectively stored to achieve hybrid energy storage.

[0044] In addition, the device can also switch promptly and flexibly between (A) deflation, energy release, power generation process and (B) inflation, energy storage, electricity storage process according to other adjustment needs such as adjusting gas storage pressure, adjusting air bag position, adjusting energy storage distribution, etc., so as to give full play to the hybrid energy storage and adjustment capabilities of the device.

[0045] Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent substitutions for some of the technical features therein; and these modifications or substitutions do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An underwater gas storage device for compressed air gravity mixed energy storage, characterized in that: include: A compressed air energy storage system, the compressed air energy storage system comprising a gas pipeline (7) extending in a vertical direction, the gas pipeline (7) being connected to a gas storage bag (6); A gravity energy storage system, the gravity energy storage system comprising a first cable (11) and a weight (8), the weight (8) being connected to the outside of an air storage bag (6) via the first cable (11); The gravity energy storage system is installed on a load-bearing frame (202), a pile foundation (201) is provided at the bottom of the load-bearing frame (202), the pile foundation (201) is fixed on the bottom plane of the water, the gravity energy storage system is arranged underwater, the air transmission pipeline (7) of the compressed air energy storage system extends into the water, and the air storage bag (6) of the compressed air energy storage system is arranged underwater.

2. The underwater gas storage device for compressed air gravity hybrid energy storage according to claim 1, characterized in that: The compressed air energy storage system comprises an electric motor (1), a compressor (2), and an air storage buffer chamber (5), wherein the electric motor (1) is connected to the compressor (2), the compressor (2) is connected to the air storage buffer chamber (5), and the air storage buffer chamber (5) is connected to a gas transmission pipeline (7).

3. The underwater gas storage device for compressed air gravity hybrid energy storage according to claim 2, characterized in that: The compressed air energy storage system comprises an expander (3) and a first generator (4); the air storage buffer chamber (5) is connected to the expander (3), and the expander (3) is connected to the first generator (4).

4. The underwater gas storage device for compressed air gravity hybrid energy storage according to claim 2, characterized in that: A valve (101) is installed on the connecting pipeline between the compressor (2) and the gas storage buffer chamber (5), and a valve (101) is also installed on the connecting pipeline between the gas storage buffer chamber (5) and the expander (3).

5. The underwater gas storage device for compressed air gravity hybrid energy storage according to claim 1, characterized in that: The gas transmission pipeline (7) is made of a flexible material, and the gas storage bag (6) is made of a flexible material.

6. The underwater gas storage device for compressed air gravity hybrid energy storage according to claim 1, characterized in that: The gravity energy storage system comprises a pulley block (10) and a pulley rope winding machine (13) fixed on a load-bearing frame (202); the pulley rope winding machine (13) is provided with a second cable (12); the second cable (12) is connected to a weight (8) through the pulley block (10).

7. The underwater gas storage device for compressed air gravity hybrid energy storage according to claim 6, characterized in that: The gravity energy storage system further comprises an upper limit device (17) and a lower limit device (9), wherein the upper limit device (17) is mounted on the upper end of the load-bearing frame (202), and the lower limit device (9) is mounted on the lower end of the load-bearing frame (202), and the first cable (11) and the second cable (12) pass through the upper limit device (17).

8. The underwater gas storage device for compressed air gravity hybrid energy storage according to claim 7, characterized in that: The weight (8) is limited between an upper limit device (17) and a lower limit device (9), and is configured to be able to move linearly through the pulling of a first cable (11) and a second cable (12).

9. The underwater gas storage device for compressed air gravity hybrid energy storage according to claim 6, characterized in that: A second generator (16) and a gearbox (15) are fixed on the pile foundation (201), and the second generator (16) is connected to the gearbox (15).

10. The underwater gas storage device for compressed air gravity hybrid energy storage according to claim 9, characterized in that: The pulley rope winding machine (13) is provided with a transmission belt (14), and the transmission belt (14) connects the pulley shaft of the pulley rope winding machine (13) and the gearbox (15).

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