Constant voltage energy storage system

Abstract

This invention discloses a constant-pressure energy storage system, belonging to the field of energy storage and power generation technology. It solves the problems of inconsistent internal pressure in existing energy storage power plants' gas storage tanks, repeated cyclic loading, which are detrimental to maintaining stable operation of the air compressor, power generation equipment, and gas storage tank, resulting in poor safety performance and the inability to provide effective maintenance conditions. The system includes: a gas storage tank with a sealing piston that divides the tank's interior into a first chamber and a second chamber, the sealing piston being movable within the tank's interior; a water reservoir located above the gas storage tank and connected to the first chamber via a water pipe; air compressor and power generation equipment, both located above the gas storage tank and connected to the second chamber via air supply pipes; the air compressor supplying compressed air to the second chamber, and the power generation equipment using the compressed air output from the second chamber to generate electricity. This invention is applicable to energy storage power plants.

Description

Technical Field

[0001] This invention relates to a constant-pressure energy storage system, belonging to the field of energy storage and power generation technology. Background Technology

[0002] Among new energy storage technologies, electrochemical energy storage and compressed air energy storage are the most mature. However, electrochemical energy storage has disadvantages such as high cost, short lifespan, and significant safety risks. In contrast, compressed air energy storage offers higher safety and advantages such as large storage capacity, long discharge time, long service life, and wide applicability of heat, cold, and electricity.

[0003] As a key component of compressed air energy storage power stations, gas storage facilities are currently mainly classified into two types: variable pressure and constant pressure. Variable pressure gas storage facilities suffer from inconsistent internal pressure and repeated cyclic loading, which is detrimental to maintaining stable operation of the air compressor, power generation equipment, and the gas storage facility itself. Currently, compressed air energy storage power station technologies that use water head pressure to provide constant pressure to the gas storage facility often cannot effectively isolate pressurized water from the gas storage facility, posing safety hazards and failing to provide effective maintenance conditions. Summary of the Invention

[0004] This invention provides a constant pressure energy storage system that can solve the problems of inconsistent internal pressure in the gas storage tank of existing compressed air energy storage power stations, repeated cyclic loading, which is not conducive to maintaining the stable operation of air compressor equipment, power generation equipment, and gas storage tank, has poor safety performance, and cannot provide effective maintenance conditions.

[0005] This invention provides a constant-pressure energy storage system, the system comprising:

[0006] A gas storage tank is provided with a sealing piston inside, which divides the inner cavity of the gas storage tank into a first chamber and a second chamber, and the sealing piston can move within the inner cavity of the gas storage tank.

[0007] A water storage tank is located above the gas storage tank and is connected to the first chamber via a water pipe.

[0008] Both the air compressor and the power generation equipment are located on the upper side of the gas storage tank and are connected to the second chamber via gas pipelines. The air compressor is used to supply compressed air to the second chamber, and the power generation equipment is used to generate electricity using the compressed air output from the second chamber.

[0009] Optionally, a sealing layer is provided on the inner wall of the gas storage tank, and the sealing piston is sealed to the sealing layer.

[0010] Optionally, the gas storage facility is a horizontal tunnel with a circular cross-section.

[0011] Optionally, the diameter of the connecting water pipe is less than or equal to half the diameter of the gas storage tank.

[0012] Optionally, the top elevation of the connecting water pipe is determined based on the difference between the normal design water level of the reservoir and the extreme water level of the gas storage tank.

[0013] Optionally, the extreme water level difference of the gas storage tank is determined based on the volume of the connecting water pipe, the volume of the gas storage tank, the water surface area at the normal water level, and the water surface area when the water level is at the top of the connecting water pipe.

[0014] Optionally, the burial depth of the gas storage tank is determined based on the top elevation of the connecting water pipe and the design pressure value inside the gas storage tank.

[0015] Optionally, the burial depth of the gas storage tank is the difference between the top elevation of the connecting water pipe and the set head difference;

[0016] The set head difference is the ratio of the design pressure value in the gas storage tank to the density of water.

[0017] Optionally, both the sealing piston and the sealing layer are made of rubber.

[0018] Optionally, the top elevation of the connecting water pipe can be calculated using the first formula;

[0019] The first formula is:

[0020] Among them, H L H is the elevation (m) of the top of the connecting water pipe. s The design normal water level of the reservoir (m); r is the radius of the connecting water pipe (m); L L R is the length of the connecting water pipe (m); R is the radius of the gas storage tank (m); L C A is the length of the gas storage facility (m); L1 The area of ​​the water surface at the normal storage level (㎡); A L2 The water surface area (m²) is when the water level is at the top of the communicating vessel.

[0021] The beneficial effects that this invention can produce include:

[0022] The constant-pressure energy storage system provided by this invention controls the head difference between the gas storage tank and the reservoir according to the required design pressure, effectively providing a constant pressure state within the gas storage tank. Furthermore, the sealing piston effectively isolates the pressure supply measurement and the gas storage measurement, thus providing an efficient operating method. Compared to existing variable-pressure gas storage tanks, the constant-pressure gas storage tank of this invention, except during maintenance, does not require repeated cyclic loading throughout its operational lifespan, maintaining a constant pressure state within the gas storage tank. This is beneficial for the stress on the chamber and the stability of the air compressor and power generation equipment, thereby significantly reducing costs. Moreover, the constant-pressure energy storage system of this invention provides effective maintenance conditions, greatly improving the working efficiency of the gas storage tank, connecting water pipes, and gas transmission pipelines. Additionally, the constant-pressure energy storage system of this invention can be co-constructed with pumped-storage power stations, hydropower stations, or reservoirs, further reducing costs. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of a constant-pressure energy storage system provided in an embodiment of the present invention;

[0024] Figure 2 This is a schematic cross-sectional view of a gas storage facility provided in an embodiment of the present invention;

[0025] Figure 3 This is a schematic cross-sectional view of a gas storage facility provided in an embodiment of the present invention.

[0026] List of components and reference numerals:

[0027] 11. Gas storage tank; 12. Sealing piston; 13. Water reservoir; 14. Connecting water pipe; 15. Air compressor equipment; 16. Power generation equipment; 17. Gas transmission pipeline; 18. Sealing layer. Detailed Implementation

[0028] The present invention will now be described in detail with reference to the embodiments, but the present invention is not limited to these embodiments.

[0029] This invention provides a constant-pressure energy storage system, such as... Figure 1 As shown, the system includes:

[0030] The gas storage chamber 11 is equipped with a sealing piston 12, which divides the inner cavity of the gas storage chamber 11 into a first chamber and a second chamber. The sealing piston 12 can move within the inner cavity of the gas storage chamber 11.

[0031] The water storage reservoir 13 is located above the gas storage reservoir 11 and is connected to the first chamber via a connecting water pipe 14.

[0032] The air compressor 15 and the power generation equipment 16 are both located on the upper side of the air storage tank 11 and are both connected to the second chamber through the air supply pipeline 17. The air compressor 15 is used to supply compressed air to the second chamber, and the power generation equipment 16 is used to generate electricity using the compressed air output from the second chamber.

[0033] refer to Figure 1 As shown, one side of the gas storage tank 11 is connected to the water storage tank 13 via a small-diameter connecting water pipe 14, and the other side of the gas storage tank 11 is connected to the air compressor equipment 15 and the power generation equipment 16 via a gas transmission pipeline 17. The elevation of the water storage tank 13 is greater than the elevation of the gas storage tank 11. Specifically, the diameter of the connecting water pipe 14 can be set to be less than or equal to half the diameter of the gas storage tank 11.

[0034] In practical applications, the gas storage 11 is a horizontal tunnel with a circular cross-section, and a sealing piston 12 is installed inside.

[0035] During peak-shaving energy storage, the air compressor 15 pressurizes the air and delivers it to the second chamber of the gas storage tank 11 through the gas pipeline 17. The gas storage tank 11 stores and stores energy by pushing the sealing piston 12 under constant air pressure. During power generation, the gas valve in the power generation equipment 16 is controlled, and the gas storage tank 11 discharges constant-pressure gas from the gas storage tank 11 to the power generation equipment 16 by pushing the sealing piston 12 under constant water pressure in the first chamber.

[0036] refer to Figure 2 and Figure 3 As shown, a sealing layer 18 is provided on the inner wall of the gas storage tank 11, and the sealing piston 12 is sealed to the sealing layer 18.

[0037] The surface of the sealing layer 18 of the gas storage tank 11 should have a certain degree of smoothness to ensure the smooth operation of the sealing piston 12 during energy storage and power generation. The sealing piston 12 and the sealing layer 18 of the gas storage tank 11 should have certain compressive strength and sealing performance, and the connection between them and the gas storage tank 11 should also be airtight. The strength of the sealing piston 12 and the sealing layer 18 of the gas storage tank 11 must meet the load design requirements of the gas storage tank 11.

[0038] The materials used for the sealing piston 12 and the sealing layer 18 are not limited to materials that are resistant to deformation, wear, and high temperatures, such as polymer materials. In practical applications, rubber materials can be used for the sealing piston 12 and the sealing layer 18.

[0039] In this embodiment of the invention, the top elevation of the connecting water pipe 14, the burial depth of the gas storage tank 11, the internal pressure value of the gas storage tank 11, and the specific cross-sectional dimensions and length of the gas storage tank 11 can be determined through design calculations. Specifically, the top elevation of the connecting water pipe 14 is determined based on the difference between the designed normal water level of the reservoir 13 and the ultimate water level of the gas storage tank 11. The ultimate water level difference of the gas storage tank 11 is determined based on the volume of the connecting water pipe 14, the volume of the gas storage tank 11, the surface area at the normal water level, and the surface area when the water level is the top of the connecting water pipe 14.

[0040] Specifically, the top elevation of the connecting water pipe 14 can be calculated using the first formula;

[0041] The first formula is:

[0042] Among them, H L The elevation (m) of the top of the connecting water pipe 14; H s The design normal water level (m) for reservoir 13; r is the radius (m) of the connecting water pipe 14; L L R is the length (m) of the connecting water pipe 14; R is the radius (m) of the gas storage tank 11; L C Length (m) of gas storage 11; A L1 The area of ​​the water surface at the normal storage level (㎡); A L2 The water surface area (m²) is when the water level is at the top of the communicating vessel.

[0043] The burial depth of the gas storage 11 can be determined based on the top elevation of the connecting water pipe 14 and the design pressure value inside the gas storage 11.

[0044] Specifically, the burial depth of gas storage cell 11 can be calculated using the second formula.

[0045] The second formula is:

[0046] In the formula: H C Elevation (m) of axis 11 of the gas storage facility; H L The elevation of the top of the connecting water pipe 14 (m); P is the design pressure value inside the gas storage tank 11 (kPa); γ w The specific weight of water (kN / m³) 3 ).

[0047] The design pressure value and specific dimensions of gas storage 11 can be determined based on power generation needs.

[0048] When the gas storage 11 needs maintenance, the water level in the reservoir 13 is lowered to below the top opening of the connecting water pipe 14, and then the water in the connecting water pipe 14 and the water-facing side of the sealing piston 12 inside the gas storage 11 is drained. At the same time, the pressure on both sides of the sealing piston 12 inside the gas storage 11 is equalized and moved to an appropriate position by controlling the power generation equipment 16 and the air compressor equipment 15. When the pressure on both sides of the sealing piston 12 drops to atmospheric pressure, the corresponding maintenance can be carried out.

[0049] The constant-pressure energy storage system provided by this invention controls the head difference between the gas storage tank 11 and the reservoir according to the required design pressure, effectively providing a constant pressure state within the gas storage tank 11. Furthermore, the sealing piston 12 effectively isolates the pressure supply measurement and the gas storage measurement, thus providing an efficient operating method. Compared to existing variable-pressure gas storage tanks, the constant-pressure gas storage tank 11 of this invention, except during maintenance, does not require repeated cyclic loading throughout its operational lifespan, maintaining a constant pressure state within the gas storage tank 11. This is beneficial for the stability of the chamber stress and the air compressor equipment 15 and the power generation equipment 16, thereby significantly reducing costs. Moreover, the constant-pressure energy storage system of this invention provides effective maintenance conditions, greatly improving the working efficiency of the gas storage tank 11, the connecting water pipe 14, and the gas transmission pipeline 17. Additionally, the constant-pressure energy storage system of this invention can be co-constructed with pumped-storage power stations, hydropower stations, or reservoirs, further reducing costs.

[0050] The above description is merely a few embodiments of this application and is not intended to limit this application in any way. Although this application discloses preferred embodiments as described above, it is not intended to limit this application. Any changes or modifications made by those skilled in the art without departing from the scope of the technical solution of this application using the disclosed technical content are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. A constant pressure energy storage system, characterized by, The system includes: A gas storage tank is equipped with a sealing piston that divides the inner cavity of the gas storage tank into a first chamber and a second chamber. The sealing piston can move within the inner cavity of the gas storage tank. The gas storage tank is a horizontal tunnel with a circular cross-section. A water storage tank is located above the gas storage tank and is connected to the first chamber via a connecting water pipe; the diameter of the connecting water pipe is less than or equal to half the diameter of the gas storage tank. Both the air compressor and the power generation equipment are installed on the upper side of the gas storage tank and are connected to the second chamber through gas pipelines; the air compressor is used to supply compressed air to the second chamber, and the power generation equipment is used to generate electricity using the compressed air output from the second chamber. The top elevation of the connecting water pipe is calculated using the first formula; The first formula is: ; in, The elevation of the top of the connecting water pipe; The reservoir is designed with a normal water level. The radius of the connecting water pipe; This refers to the length of the connecting water pipe; The radius of the gas storage facility; The length of the gas storage facility; This represents the surface area of ​​the water at the normal storage level. The water surface area when the water level is at the top of the communicating vessel; The burial depth of the gas storage facility is calculated using the second formula; The second formula is: ; in, This refers to the elevation of the gas storage facility's axis. The elevation of the top of the connecting water pipe; Design pressure value for the gas storage facility; This is the specific gravity of water.

2. The constant pressure energy storage system of claim 1, wherein, The gas storage tank has a sealing layer on its inner wall, and the sealing piston is sealed to the sealing layer.

3. The constant pressure energy storage system of claim 2, wherein, Both the sealing piston and the sealing layer are made of rubber.

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