Hydraulic compressed air hybrid energy storage power generation system and method of operation thereof

Abstract

The present application relates to a kind of water pressure type compressed air hybrid energy storage power generation system and its operating method, belong to physical energy storage technical field.The compressed expansion mechanical module includes: for compressing gas, and compressed gas is delivered to storage module;Storage module: for receiving the gas of compressed expansion mechanical module to store energy, and then the energy stored in energy storage is delivered to power generation module;Power generation module: the energy generated by the high-pressure gas stored in air storage module is converted into electric energy.The present application improves the problem that the site selection of pumped storage technology is limited by adopting the way of gas storage tank and water storage, and the site selection is more flexible.The present application reduces the operating water head amplitude of hydraulic machinery by adopting the way of gas supplement of gas storage tank, improves the operating efficiency and stability of hydraulic machinery.

Description

TECHNICAL FIELD

[0001] The present application relates to a hybrid energy storage power generation system and a method thereof, and belongs to the technical field of physical energy storage. BACKGROUND

[0002] With the continuous consumption of fossil energy, environmental pollution problems are increasingly serious, and green transformation of energy structure is imperative. In recent years, the installed capacity of wind and solar energy has continued to increase rapidly; as of June 2024, the installed capacity of wind power is 467 million kW, and the installed capacity of photovoltaic power generation is 714 million kW. With the continuous and rapid increase of intermittent and uncertain wind and solar grid-connected capacity, the balance between supply and demand of the power grid is further highlighted. Therefore, the power grid urgently needs energy storage equipment to enhance its regulation and accommodation capacity. Based on pumped storage and compressed air energy storage technology, scholars have proposed pumped air hybrid energy storage technology. For example: the patent with the publication number CN117267035A and the invention name of a constant pressure non-combustion type pumped air coupled compressed air energy storage system based on water pressure compensation, the technical scheme of which, compared with the conventional pumped storage power station, stores energy by compressing air to the upstream reservoir through the compressed air energy storage system, and generates electricity by the work of the expander and the water turbine during power generation, but the site selection of the scheme is limited; the patent with the publication number CN112134363B and the invention name of an internal temperature control liquid piston device for isothermal compressed air energy storage, the technical scheme of which compresses air to store energy by injecting water into the tank, but the air pressure amplitude in the tank in the scheme does not match the water head amplitude of the water power machinery.

[0003] Therefore, it is urgent to propose a water pressure type compressed air hybrid energy storage power generation system and its operation method to solve the above technical problems. SUMMARY

[0004] To solve the above problems, a water pressure type compressed air hybrid energy storage power generation system and its operation method are provided, and a brief summary of the present application is given below to provide a basic understanding of some aspects of the present application. It should be understood that this summary is not an exhaustive summary of the present application. It is not intended to determine the key or important parts of the present application, nor to limit the scope of the present application.

[0005] The technical scheme of the present application:

[0006] A water pressure type compressed air hybrid energy storage power generation system, comprising a compression and expansion mechanical module, an air storage module and a power generation module;

[0007] The compression and expansion mechanical module is used for compressing gas and delivering the compressed gas to the air storage module;

[0008] The air storage module is used for receiving the gas from the compression and expansion mechanical module to store energy, and delivering the stored energy to the power generation module;

[0009] Power generation module: converting the energy generated by the high-pressure gas stored in the air storage module into electric energy.

[0010] Preferably: the compression expansion mechanical module comprises a piston compressor and an expander, the piston compressor comprises a piston cavity and a piston, the piston cavity is provided with a piston which can slide up and down, the piston compressor is connected with the air storage module, and the expander is connected with the power generation module.

[0011] Preferably: the air storage module comprises a first gas storage tank, a second gas storage tank and a heat exchange device, the piston cavity outlet of the piston compressor is connected with the first gas storage tank inlet, the first gas storage tank outlet is connected with the second gas storage tank inlet and outlet, the first gas storage tank outlet and the second gas storage tank inlet and outlet are connected with the power generation module, and the first gas storage tank and the second gas storage tank are connected with the heat exchange device.

[0012] The heat exchange device is a reinforced heat exchange device, which comprises a water tank, a first lower water pump, a first upper water pump, a second lower water pump, a second upper water pump, a first lower spiral pipe, a first upper spiral pipe, a second lower spiral pipe and a second upper spiral pipe, the first upper spiral pipe and the first lower spiral pipe arranged in an up-down manner are installed in the first gas storage tank, one end of the first upper spiral pipe is connected with the output end of the first upper water pump, the other end of the first upper spiral pipe is connected with the upper part of the water tank, the input end of the first upper water pump is connected with the upper part of the water tank through a long pipe, one end of the first lower spiral pipe is connected with the output end of the first lower water pump, the other end of the first lower spiral pipe is connected with the lower part of the water tank, the second upper spiral pipe and the second lower spiral pipe arranged in an up-down manner are installed in the second gas storage tank, one end of the second upper spiral pipe is connected with the output end of the second upper water pump, the other end of the second upper spiral pipe is connected with the upper part of the water tank, the input end of the second upper water pump is connected with the upper part of the water tank through a long pipe, one end of the second lower spiral pipe is connected with the output end of the second lower water pump, the other end of the second lower spiral pipe is connected with the lower part of the water tank, the input end of the second lower water pump is connected with the lower part of the water tank, and the water tank is filled with water.

[0013] Preferably, the power generation module comprises a first liquid piston, a second liquid piston and a hydraulic generator set, the first liquid piston and the second liquid piston are cylindrical shells with cavities, the cavities are filled with liquid (water), the water in the cavities is driven to rise and fall by gas, the upper inlet of the first liquid piston and the upper inlet of the second liquid piston are connected with the air storage module, the upper outlet of the first liquid piston and the upper outlet of the second liquid piston are connected with the expander, the upper inlets and outlets in this paragraph can be used to transport gas, the lower outlet of the first liquid piston is connected with the lower inlet of the second liquid piston through the hydraulic generator set, and the lower inlet of the first liquid piston is connected with the lower outlet of the second liquid piston through the hydraulic generator set, and the lower inlets and outlets in this paragraph are used to transport liquid.

[0014] Preferably, the power generation module further comprises a first gas bag accumulator, a second gas bag accumulator, a first valve, a second valve, a third valve and a fourth valve, one end of the hydraulic generator set is connected with a first opening of a first three-way pipe, the lower outlet of the first liquid piston is connected with a second opening of the first three-way pipe through the second valve, the first gas bag accumulator is arranged between the lower outlet of the first liquid piston and the second valve, the lower outlet of the second liquid piston is connected with a third opening of the first three-way pipe through the first valve, the second gas bag accumulator is arranged between the lower outlet of the second liquid piston and the first valve, the other end of the hydraulic generator set is connected with a first opening of a second three-way pipe, the lower inlet of the first liquid piston is connected with a second opening of the second three-way pipe through the third valve, and the lower inlet of the second liquid piston is connected with a third opening of the second three-way pipe through the fourth valve.

[0015] Preferably, the compression and expansion mechanical module further comprises a fifth valve and a sixth valve, the fifth valve is arranged on a pipeline between the piston cavity outlet of the piston compressor and the inlet of the first gas tank, and the sixth valve is arranged on a pipeline of the piston cavity inlet of the piston compressor;

[0016] The storage module is an air storage module, and the storage module further comprises a seventh valve and an eighth valve, one end of a first connecting pipe is connected with the outlet of the first gas tank, the middle of the first connecting pipe is connected with the inlet and outlet of a second gas tank, the other end of the first connecting pipe is connected with a first opening of a third three-way pipe, the seventh valve is arranged between the outlet of the first gas tank and the inlet and outlet of the second gas tank, and the eighth valve is arranged between the inlet and outlet of the second gas tank and the first opening of the third three-way pipe;

[0017] The power generation module further comprises a ninth valve, a tenth valve, an eleventh valve and a twelfth valve, the second opening of the third three-way pipe is connected with the upper inlet of the first liquid piston, the third opening of the third three-way pipe is connected with the upper inlet of the second liquid piston, the eleventh valve is arranged between the second opening of the third three-way pipe and the upper inlet of the first liquid piston, the twelfth valve is arranged between the third opening of the third three-way pipe and the upper inlet of the second liquid piston, the upper outlet of the first liquid piston is provided with the ninth valve, the upper outlet of the second liquid piston is provided with the tenth valve, one end of the second connecting pipe is connected with the tenth valve, the middle of the second connecting pipe is connected with the ninth valve, the other end of the second connecting pipe is connected with the expander, and the valves can be solenoid valves.

[0018] Preferably, the air storage module further comprises a first pressure sensor and a second pressure sensor, the first pressure sensor is arranged in the first air tank, and the second pressure sensor is arranged in the second air tank.

[0019] The power generation module further comprises a third pressure sensor and a fourth pressure sensor, the third pressure sensor is arranged in the upper part of the first liquid piston, and the fourth pressure sensor is arranged in the upper part of the second liquid piston.

[0020] A method for operating a water pressure type compressed air hybrid energy storage power generation system, which adopts a water pressure type compressed air hybrid energy storage power generation system, and comprises the following steps: a pressure presetting process, an energy storage process and a power generation process.

[0021] Step 1, the pressure presetting process:

[0022] In the pressure presetting process, the seventh valve is kept open; the working conditions of the pressure presetting process include: a piston upgoing situation and a piston downgoing situation.

[0023] Step 1.1, the piston upgoing situation:

[0024] When the piston upgoes, the sixth valve is closed, the eighth valve is closed, the piston in the piston compressor is pushed to move upwards, the water in the piston cavity is pushed to move upwards, and the compressed air is compressed; when the air pressure is consistent with the air pressure in the first air tank, the fifth valve is opened, and the air in the piston compressor cavity is discharged into the first air tank and the second air tank; when the piston in the piston compressor reaches the highest point, the fifth valve is closed, and the piston downgoing situation is switched.

[0025] Step 1.2, the piston downgoing situation:

[0026] When the piston downgoes, the sixth valve is opened, the piston in the piston compressor moves downwards, the air volume in the piston cavity increases, and under the action of negative pressure, the air outside is sucked into the piston cavity; when the piston runs to the lowest point, the sixth valve is closed, and the piston upgoing situation is switched.

[0027] Step 1.3: Repeat the piston's downward and upward movements multiple times until the average pressure measured by the first and second pressure sensors reaches the set pressure. p At 0:00, the reciprocating compressor stops, the fifth valve closes, and the pressure preset process ends;

[0028] Step 2, Energy Storage Operating Conditions:

[0029] The energy storage operating conditions include two operating scenarios: the first and second gas storage tanks jointly storing energy, and the first gas storage tank storing energy alone.

[0030] Step 2.1, Energy storage scenario where the first and second gas storage tanks are used together:

[0031] The fifth valve opens; the reciprocating compressor operates with the piston moving upwards and downwards, continuously filling the first and second air storage tanks with compressed air to store energy; as the energy storage process continues, the air pressure in the first and second air storage tanks continuously rises, until the average pressure measured by the first and second pressure sensors reaches the set pressure. p At 1 o'clock, the seventh valve is closed, ending the situation where the first and second gas storage tanks jointly store energy; the system then enters the operation mode where the first gas storage tank stores gas alone.

[0032] Step 2.2, Energy storage scenario of the first gas storage tank alone:

[0033] The reciprocating compressor continues to operate, compressing air into the first air tank to store energy during the piston's upward and downward movements. As air continuously enters the first air tank, the air pressure inside the tank continuously rises. When the air pressure measured by the first pressure sensor reaches the set pressure... p At 2 o'clock, the situation of the first gas storage tank storing energy alone ended, and the piston compressor stopped; p 2> p 1> p 0;

[0034] Step 3, Power Generation Stage:

[0035] During power generation, there are three scenarios: air intake by the first liquid piston, air intake by the second liquid piston, and air replenishment from the first gas storage tank to the second gas storage tank.

[0036] Step 3.1, Air intake situation of the first liquid piston:

[0037] The second valve, the fourth valve, the tenth valve, the eleventh valve and the eighth valve are opened, the air in the second air tank is expanded and enters into the first liquid piston, the water at the bottom of the first liquid piston is squeezed out to the water turbine generator set to generate electricity; the water after generating electricity returns to the second liquid piston, the air at the top of the second liquid piston is squeezed out to the expander to generate electricity, and the gas after work returns to the external environment; when the water level in the first liquid piston reaches the lower limit water level, the second valve, the fourth valve, the tenth valve and the eleventh valve are closed, and the second liquid piston air intake condition is switched to;

[0038] Step 3.2, second liquid piston air intake condition:

[0039] The first valve, the third valve, the ninth valve and the twelfth valve are opened, the air in the second air tank is expanded and enters into the second liquid piston, the water at the bottom of the second liquid piston is discharged to the water turbine generator set to generate electricity and then returns to the first liquid piston, the air at the top of the first liquid piston is squeezed out to the expander to generate electricity and then returns to the external environment; when the water level in the second liquid piston reaches the lower limit water level, the first liquid piston air intake condition is switched to; the first valve, the third valve, the ninth valve and the twelfth valve are closed;

[0040] With the continuous generation of electricity, the air pressure in the second air tank decreases, and when the air pressure in the second air tank decreases to p 0, the second air tank enters the first air tank air supplement condition;

[0041] Step 3.3, air tank 22 air supplement condition to air tank 21:

[0042] In this process, the valve 909 is opened, the air in the first air tank flows to the second air tank, the air pressure in the second air tank rises, and when the air pressure in the second air tank rises to the set pressure p 1, the air supplement process is completed, and in the process of step 3.3, the system is still in the process of continuously entering the first liquid piston air intake and the second liquid piston air intake;

[0043] In the air supplement process, the air pressure in the first air tank decreases, and after multiple air supplement operations, when the pressure value measured by the first pressure sensor decreases to p 1, the seventh valve is always opened, and the air in the first air tank and the second air tank expands and works together; when the pressure values measured by the first pressure sensor and the second pressure sensor are both less than p 0, the electricity generation process is completed.

[0044] Preferably: in steps one and two, during energy storage, start the heat exchange device to reduce the temperature of the first air tank and the second air tank; when the air in the piston cavity is discharged into the first air tank and the second air tank, the air in the first air tank and the second air tank is compressed, and the air pressure and temperature rise; in this process, start the first upper water pump to introduce water into the first upper spiral pipe in the first air tank to absorb the heat released during air compression, and slow down the rate of rise of the air temperature in the first air tank; start the second upper water pump to introduce water into the second upper spiral pipe in the second air tank to absorb the heat released during air compression and reduce the air temperature in the second air tank; in this process, the water temperature rises slightly; during power generation, start the enhanced heat exchange device to increase the temperature of the first air tank and the second air tank; when the air in the first air tank expands, the air pressure and temperature decrease; in this process, start the first lower water pump to introduce water into the first lower spiral pipe in the first air tank to supplement the heat absorbed during air expansion, and slow down the rate of decrease of the air temperature in the first air tank; when the air in the second air tank expands, the air pressure and temperature decrease, and the second lower water pump is started to introduce water into the second lower spiral pipe in the second air tank to supplement the heat absorbed during air expansion and reduce the rate and amplitude of the decrease in the air temperature in the second air tank.

[0045] The present application has the following beneficial effects:

[0046] 1) The present application improves the problem of limited site selection for pumped storage technology by using air storage tanks to store air and water, and the site selection is more flexible.

[0047] 2) The present application reduces the operating water head amplitude of the hydraulic machinery by using air storage tanks to supplement air, and improves the operating efficiency and stability of the hydraulic machinery.

[0048] 3) The present application increases the spiral pipe in the first air tank and the second air tank, enhances the heat transfer performance during air compression and expansion, and improves the round-trip efficiency during air compression and expansion, with high energy utilization rate.

[0049] 4) The devices of the energy storage system described in the present application are relatively mature, and no additional fossil fuel is consumed for combustion during energy storage and power generation, and no environmental pollution is generated.

[0050] 5) The energy storage efficiency of the system after large-scale can reach more than 70%. BRIEF DESCRIPTION OF DRAWINGS

[0051] Fig. 1 The present application is a water pressure type compressed air hybrid energy storage and power generation system.

[0052] Fig. 2 The present application is a water pressure type compressed air hybrid energy storage and power generation system according to the third embodiment.

[0053] Fig. 3 is a water pressure type compressed air hybrid energy storage power generation system according to embodiment four.

[0054] In the figure, 1-piston compressor, 101-spraying device, 4-hydropower generator set, 5-expander, 21-first gas storage tank, 22-second gas storage tank, 23-water tank, 31-first liquid piston, 32-second liquid piston, 51-first expander, 52-second expander, 61-first gas bag type accumulator, 62-second gas bag type accumulator, 71-first lower water pump, 72-first upper water pump, 73-second lower water pump, 74-second upper water pump, 81-first pressure sensor, 82-second pressure sensor, 83-third pressure sensor, 84-fourth pressure sensor, 901-first valve, 902-second valve, 903-third valve, 904-fourth valve, 905-ninth valve, 906-tenth valve, 907-eleventh valve, 908-twelfth valve, 909-seventh valve, 910-eighth valve, 911-fifth valve, 912-sixth valve, 913-first upper water replenishment valve, 914-second upper water replenishment valve, 915-first lower water replenishment valve, 916-second lower water replenishment valve, 917-seventeenth valve, 918-eighteenth valve. Embodiment

[0055] In order to make the objects, technical solutions and advantages of the present application clearer, the present application will be described below in detail through specific embodiments shown in the drawings. However, it should be understood that these descriptions are only exemplary and are not intended to limit the scope of the present application. In addition, in the following description, the description of known structures and technologies is omitted to avoid unnecessary confusion of the concept of the present application.

[0056] Embodiment one: combined Figs. 1-3 In this embodiment, a water pressure type compressed air hybrid energy storage power generation system according to this embodiment includes a compression and expansion mechanical module, an air storage module, and a power generation module.

[0057] Compression and expansion mechanical module: used for compressing gas (air) and delivering the compressed gas to the air storage module;

[0058] The compression expansion mechanical module comprises a piston compressor 1 and an expander 5, the piston compressor 1 comprises a piston cavity and a piston, the piston cavity is provided with a piston which can slide up and down, the piston cavity has an inner cavity which is open at the lower part, the piston cavity and the piston connecting part are provided with a sealing ring, the lower part of the piston is connected with the driving end of a driving device (such as a linear motor or a hydraulic rod), the piston can move up and down in the inner cavity of the piston cavity, the distance between the upper side of the piston and the upper part of the inner cavity of the piston cavity is changed to realize the supplement and compression of the gas, the relative position between the driving device shell and the piston cavity is fixed, that is, the driving device shell and the piston cavity can be bolted on the same support, the upper part of the piston cavity is provided with an outlet and an inlet, the piston compressor 1 is connected with an air storage module, and the expander 5 is connected with a power generation module;

[0059] The compression expansion mechanical module further comprises a spraying device 101, a nozzle of the spraying device 101 is arranged at the upper part of the inner cavity of the piston cavity, the spraying device 101 is connected with the lower part of a water supplement tank, is used for spraying water to the inner cavity of the piston cavity to reduce the temperature, and simultaneously increases the water content in the air to reduce the evaporation of the water in the power generation module;

[0060] The compression expansion mechanical module further comprises a fifth valve 911 and a sixth valve 912, the fifth valve 911 is arranged on the pipeline between the outlet of the piston cavity of the piston compressor 1 and the inlet of the first gas storage tank 21, and the sixth valve 912 is arranged on the pipeline of the inlet of the piston cavity of the piston compressor 1;

[0061] The air storage module is used for receiving the gas of the compression expansion mechanical module to store energy, and then delivering the stored energy to the power generation module.

[0062] The air storage module comprises a first gas storage tank 21, a second gas storage tank 22 and a reinforced heat exchange device, the outlet of the piston cavity of the piston compressor 1 is connected with the inlet of the first gas storage tank 21, the outlet of the first gas storage tank 21 is connected with the inlet and outlet of the second gas storage tank 22, the outlet of the first gas storage tank 21 and the inlet and outlet of the second gas storage tank 22 are connected with the power generation module, and the first gas storage tank 21, the second gas storage tank 22 and the reinforced heat exchange device are connected; the first gas storage tank 21 can supply gas alone and also can supplement the second gas storage tank 22.

[0063] The air storage module further comprises a seventh valve 909 and an eighth valve 910, one end of a first connecting pipe is connected with the outlet of the first gas storage tank 21, the middle part of the first connecting pipe is connected with the inlet and outlet of the second gas storage tank 22, the other end of the first connecting pipe is connected with the first opening of a third three-way pipe, the seventh valve 909 is arranged between the outlet of the first gas storage tank 21 and the inlet and outlet of the second gas storage tank 22, and the eighth valve 910 is arranged between the inlet and outlet of the second gas storage tank 22 and the first opening of the third three-way pipe.

[0064] The air storage module further comprises a first pressure sensor 81 and a second pressure sensor 82, the first pressure sensor 81 is arranged in the first air tank 21, and the second pressure sensor 82 is arranged in the second air tank 22; by adopting the air tank air supplementing mode, the operation water head amplitude of the hydraulic machine is reduced, and the operation efficiency and stability of the hydraulic machine are improved;

[0065] The reinforced heat exchange device comprises a water tank 23, a first lower water pump 71, a first upper water pump 72, a second lower water pump 73, a second upper water pump 74, a first lower spiral pipe, a first upper spiral pipe, a second lower spiral pipe and a second upper spiral pipe, the water tank 23, a first lower water supplement valve 915, the first lower water pump 71 and the first lower spiral pipe are sequentially and circularly connected, the water tank 23, a first upper water supplement valve 913, the first upper water pump 72 and the first upper spiral pipe are sequentially and circularly connected, the water tank 23, a second upper water supplement valve 914, the second upper water pump 74 and the second upper spiral pipe are sequentially and circularly connected, and the water tank 23, a second lower water supplement valve 916, the second lower water pump 73 and the second lower spiral pipe are sequentially and circularly connected, the first upper spiral pipe and the first lower spiral pipe arranged in the upper and lower positions are arranged in the first air tank 21, one end of the first upper spiral pipe is connected with the output end of the first upper water pump 72, the other end of the first upper spiral pipe is connected with the upper portion of the water tank 23, the input end of the first upper water pump 72 is connected with the upper portion of the water tank through a long pipe, one end of the first lower spiral pipe is connected with the output end of the first lower water pump 71, the other end of the first lower spiral pipe is connected with the lower portion of the water tank, the second upper spiral pipe and the second lower spiral pipe arranged in the upper and lower positions are arranged in the second air tank 22, one end of the second upper spiral pipe is connected with the output end of the second upper water pump 74, the other end of the second upper spiral pipe is connected with the upper portion of the water tank, the input end of the second upper water pump 74 is connected with the upper portion of the water tank through another long pipe, one end of the second lower spiral pipe is connected with the output end of the second lower water pump 73, the other end of the second lower spiral pipe is connected with the lower portion of the water tank, the input end of the second lower water pump 73 is connected with the lower portion of the water tank, and the water tank is filled with water; the spiral pipes arranged in the first air tank 21 and the second air tank 22 enhance the heat transfer performance in the air compression and expansion process and improve the back-and-forth efficiency in the air compression and expansion process;

[0066] The power generation module converts the pressure potential energy generated by the high-pressure gas stored in the air storage module into electric energy;

[0067] The power generation module comprises a first liquid piston 31, a second liquid piston 32 and a hydraulic generator set 4, the first liquid piston 31 and the second liquid piston 32 are cylindrical or cubic shell bodies with cavities, liquid (water) is contained in the cavities, water is lifted and lowered in the cavities by gas driving, the upper inlet of the first liquid piston 31 and the upper inlet of the second liquid piston 32 are connected with the air storage module, the upper outlet of the first liquid piston 31 and the upper outlet of the second liquid piston 32 are connected with the expander 5, the upper inlet and outlet in this section can be used for conveying gas, the lower outlet of the first liquid piston 31 is connected with the lower inlet of the second liquid piston 32 through the hydraulic generator set 4, and the lower inlet of the first liquid piston 31 is connected with the lower outlet of the second liquid piston 32 through the hydraulic generator set 4, the lower inlet and outlet in this section are used for conveying liquid;

[0068] The power generation module further comprises a first gas bag type accumulator 61, a second gas bag type accumulator 62, a first valve 901, a second valve 902, a third valve 903 and a fourth valve 904, one end of the hydraulic generator set 4 is connected with a first opening of a first three-way pipe, the lower outlet of the first liquid piston 31 is connected with a second opening of the first three-way pipe through the second valve 902, the first gas bag type accumulator 61 is arranged between the lower outlet of the first liquid piston 31 and the second valve 902, the lower outlet of the second liquid piston 32 is connected with a third opening of the first three-way pipe through the first valve 901, the second gas bag type accumulator 62 is arranged between the lower outlet of the second liquid piston 32 and the first valve 901, the other end of the hydraulic generator set 4 is connected with a first opening of a second three-way pipe, the lower inlet of the first liquid piston 31 is connected with a second opening of the second three-way pipe through the third valve 903, and the lower inlet of the second liquid piston 32 is connected with a third opening of the second three-way pipe through the fourth valve 904;

[0069] The power generation module further comprises a ninth valve 905, a tenth valve 906, an eleventh valve 907 and a twelfth valve 908, the second opening of the third three-way pipe is connected with the upper inlet of the first liquid piston 31, the third opening of the third three-way pipe is connected with the upper inlet of the second liquid piston 32, the eleventh valve 907 is arranged between the second opening of the third three-way pipe and the upper inlet of the first liquid piston 31, the twelfth valve 908 is arranged between the third opening of the third three-way pipe and the upper inlet of the second liquid piston 32, the upper outlet of the first liquid piston 31 is provided with the ninth valve 905, the upper outlet of the second liquid piston 32 is provided with the tenth valve 906, one end of the second connecting pipe is connected with the tenth valve 906, the middle part of the second connecting pipe is connected with the ninth valve 905, and the other end of the second connecting pipe is connected with the expander 5; the valve can be an electromagnetic valve; the energy storage system is relatively mature, and the energy storage and power generation operation do not need to consume additional fossil fuels, and no environmental pollution is generated; the energy storage efficiency of the system after being large-sized can reach more than 70%;

[0070] The power generation module further comprises a third pressure sensor 83 and a fourth pressure sensor 84, the third pressure sensor 83 is arranged in the upper part of the first liquid piston 31, and the fourth pressure sensor 84 is arranged in the upper part of the second liquid piston 32.

[0071] Specific implementation method two: combined with Fig. 1 The present embodiment is explained, and the operation method of the water pressure type compressed air mixed energy storage power generation system in the present embodiment adopts a water pressure type compressed air mixed energy storage power generation system, which comprises a compression and expansion mechanical module, an air storage module and a power generation module;

[0072] The compression and expansion mechanical module comprises a piston compressor 1, an expander 5, a fifth valve 911, a sixth valve 912 and a spraying device 101; wherein the piston cavity of the piston compressor is connected with the first gas storage tank 21 and the external environment through two pipelines; the expander is connected with the first liquid piston 31 and the second liquid piston 32 through a pipeline;

[0073] The air storage module comprises a first air tank 21, a second air tank 22, a water tank 23, a first lower water pump 71, a first upper water pump 72, a second lower water pump 73, a second upper water pump 74, and a seventh valve 909; wherein the first air tank 21 and the second air tank 22 are connected by a pipeline; a spiral pipeline is installed in the upper part and the lower part of the first air tank 21; the pipeline in the lower part is connected with the first lower water pump 71, and is used for passing in normal temperature water to cool the air; the pipeline in the upper part is connected with the first upper water pump 72, and is used for passing in heated water to heat the air; a spiral pipeline is installed in the upper part and the lower part of the second air tank 22; the pipeline in the lower part is connected with the second lower water pump 73, and is used for passing in 25℃ normal temperature water to cool the air; the pipeline in the upper part is connected with the second upper water pump 74, and is used for passing in heated water to heat the air; a first pressure sensor 81 is installed in the first air tank 21, and a second pressure sensor 82 is installed in the second air tank 22;

[0074] The power generation module comprises a first liquid piston 31, a second liquid piston 32, a hydraulic generator set 4, a first air bag type accumulator 61, a second air bag type accumulator 62, a third pressure sensor 83, a fourth pressure sensor 84, a first valve 901, a second valve 902, a third valve 903, a fourth valve 904, a ninth valve 905, a tenth valve 906, an eleventh valve 907, and a twelfth valve 908; two pipelines are connected at the top of the first liquid piston 31, and are connected with the expander and the second air tank 22 respectively; two pipelines are connected at the top of the second liquid piston 32, and are connected with the expander and the second air tank 22 respectively; two parallel pipelines are connected between the first liquid piston 31 and the second liquid piston 32, and two air bag type accumulators are connected in the upper pipeline; a hydraulic generator set is connected in the pipeline between the two pipelines;

[0075] The compression and expansion mechanical module comprises a piston compressor 1, an expander 5, a fifth valve 911, a sixth valve 912, and a spraying device 101; during energy storage, the air in the piston cavity is first compressed, and then discharged into the first air tank 21 and the second air tank 22; after the air in the piston cavity is completely discharged, the piston cavity absorbs air from the external environment; the spraying device 101 is installed at the top of the piston cavity, and is used for enhancing the heat transfer performance between the air and the water during air compression, and reducing the air temperature amplitude;

[0076] The method comprises the following steps: a pressure presetting process, an energy storage process, and a power generation process;

[0077] Step one, the pressure presetting process:

[0078] During the pressure presetting process, the seventh valve 909 is kept open; the working conditions of the pressure presetting process include: the piston upgoing condition and the piston downgoing condition;

[0079] Step 1.1, the piston upgoing condition:

[0080] When the piston upgoes, the sixth valve 912 is closed, the eighth valve 910 is closed, the piston in the piston compressor 1 is pushed to move upwards, the water body in the piston cavity is pushed to move upwards, and the compressed air is compressed; when the air pressure is consistent with the air pressure in the first air tank 21, the fifth valve 911 is opened, and the air in the cavity of the piston compressor 1 is discharged into the first air tank 21 and the second air tank 22; when the piston in the piston compressor 1 reaches the highest point, the fifth valve 911 is closed, and the piston downgoing condition is switched;

[0081] Step 1.2, the piston downgoing condition:

[0082] When the piston downgoes, the sixth valve 912 is opened, the piston in the piston compressor 1 moves downwards, the air volume in the piston cavity increases, and under the action of negative pressure, the air outside is sucked into the piston cavity; when the piston runs to the lowest point, the sixth valve 912 is closed, and the piston upgoing condition is switched;

[0083] Step 1.3, the piston downgoing and upgoing process is repeated for many times, when the average value of the pressure measured by the first pressure sensor 81 and the second pressure sensor 82 reaches the set pressure p 0, the piston compressor 1 is stopped, the fifth valve 911 is closed, and the pressure presetting process is ended;

[0084] Step two, the energy storage working condition:

[0085] The energy storage working condition includes two running conditions: the first air tank 21 and the second air tank 22 jointly store energy condition and the first air tank 21 stores energy alone condition;

[0086] Step 2.1, the first air tank 21 and the second air tank 22 jointly store energy condition:

[0087] The fifth valve 911 is opened; the piston compressor 1 runs in the piston upgoing and piston downgoing conditions, and constantly charges the compressed air into the first air tank 21 and the second air tank 22 to store energy; with the continuous progress of the energy storage process, the air pressure in the first air tank 21 and the second air tank 22 continuously rises, when the average value of the pressure measured by the first pressure sensor 81 and the second pressure sensor 82 reaches the set pressure p 1, the seventh valve 909 is closed, and the first air tank 21 and the second air tank 22 jointly store energy condition is ended; the system enters the first air tank 21 stores energy alone running condition;

[0088] When the air in the piston cavity is discharged into the first air tank 21 and the second air tank 22, the air in the first air tank 21 and the second air tank 22 is compressed, and the air pressure and temperature rise; in this process, the first lower water pump 71 is started to introduce normal temperature water into the first air tank 21 to absorb the heat released when the air is compressed, reducing the rise of the air temperature in the first air tank 21; the second lower water pump 73 is started to introduce normal temperature water into the second air tank 22 to absorb the heat released when the air is compressed, reducing the rise of the air temperature in the second air tank 22;

[0089] Step 2.2, the first air tank 21 alone energy storage case:

[0090] The piston compressor 1 continues to run in the process of piston upstroke and piston downstroke, compressing air into the first air tank 21 to store energy; as air continues to enter the first air tank 21, the air pressure in the first air tank 21 rises continuously; when the air pressure measured by the first pressure sensor 81 reaches the set pressure p 2, the first air tank 21 alone energy storage case ends, and the piston compressor 1 stops; p 2> p 1> p 0;

[0091] When the air in the piston cavity is discharged into the first air tank 21, the air in the first air tank 21 is compressed, and the air pressure and temperature rise; in this process, the first lower water pump 71 is started to introduce normal temperature water into the first air tank 21 to absorb the heat released when the air is compressed, reducing the rise of the air temperature in the first air tank 21;

[0092] Step three, power generation stage:

[0093] When generating electricity, there are three cases including first liquid piston 31 intake, second liquid piston 32 intake and first air tank 21 to second air tank 22 air supplement;

[0094] Step 3.1, first liquid piston 31 intake:

[0095] The second valve 902, the fourth valve 904, the tenth valve 906, the eleventh valve 907 and the eighth valve 910 are opened, the first valve 901, the third valve 903, the ninth valve 905, the twelfth valve 908 are closed, the air in the second air tank 22 expands and enters into the first liquid piston 31, the water at the bottom of the first liquid piston 31 is squeezed out to the water turbine generator set 4 to do work and generate electricity; the water after generating electricity returns to the second liquid piston 32, the air at the top of the second liquid piston 32 is squeezed out to the expander 5 to do work and generate electricity, and the gas after work returns to the outside environment; when the water level in the first liquid piston 31 reaches the lower limit water level, the second valve 902, the fourth valve 904, the tenth valve 906 and the eleventh valve 907 are closed, and the second liquid piston 32 is switched to the air intake state;

[0096] Step 3.2, the second liquid piston 32 air intake:

[0097] The first valve 901, the third valve 903, the ninth valve 905 and the twelfth valve 908 are opened, the air in the second air tank 22 expands and enters into the second liquid piston 32, the water at the bottom of the second liquid piston 32 is discharged to the water turbine generator set 4 to do work and generate electricity and then returns to the first liquid piston 31, the air at the top of the first liquid piston 31 is squeezed out to the expander 5 to do work and generate electricity and then returns to the outside environment; when the water level in the second liquid piston 32 reaches the lower limit water level, the first liquid piston 31 is switched to the air intake state; the first valve 901, the third valve 903, the ninth valve 905 and the twelfth valve 908 are closed;

[0098] With the continuous generation of electricity, the air pressure in the second air tank 22 decreases, and when the air pressure in the second air tank 22 decreases to p 0, the second air tank 22 enters the air supplement state to the first air tank 21;

[0099] Step 3.3, the air tank 22 supplements air to the air tank 21:

[0100] In this process, the valve 909 is opened, the air in the first air tank 21 flows to the second air tank 22, the air pressure in the second air tank 22 rises, and when the air pressure in the second air tank 22 rises to the set pressure p 1, the air supplement process is completed, and in the process of step 3.3, the system is still in the process of continuously entering the first liquid piston 31 and the second liquid piston 32;

[0101] In the air supplement process, the air pressure in the first air tank 21 decreases, and after multiple air supplement operations, when the pressure value measured by the pressure sensor 81 decreases to pWhen the first pressure sensor 81 and the second pressure sensor 82 measure pressure values less than the first pressure threshold value and the second pressure threshold value respectively, the seventh valve 909 is opened, and the air in the first air tank 21 and the second air tank 22 expands and does work together. p After 0, the power generation process ends.

[0102] The application improves the problem of limited site selection of pumped storage technology by adopting the way of storing air and water in air tanks, and the site selection is more flexible. At the same time, the stored air can not only be used to drive the water turbine generator set in the water storage mode to generate power, but also can be recycled and used to drive the expander 5 to generate power.

[0103] In steps one and two, when the piston goes up, the air is compressed, and the spraying device 101 sprays liquid droplets to enhance the heat transfer performance between the air and water in the cavity, reduce the air temperature rise, and reduce the compression power consumption.

[0104] During energy storage, the heat exchange strengthening device is started to reduce the temperature of the first air tank 21 and the second air tank 22. When the air in the piston cavity is discharged into the first air tank 21 and the second air tank 22, the air in the first air tank 21 and the second air tank 22 is compressed, and the air pressure and temperature rise. In this process, the first upper water pump 72 is started to pass normal temperature water into the first upper spiral pipe in the first air tank 21 to absorb the heat released when the air is compressed, and the air temperature rise rate in the first air tank 21 is slowed down. The second upper water pump 74 is started to pass normal temperature water into the second upper spiral pipe in the second air tank 22 to absorb the heat released when the air is compressed, and the air temperature rise rate in the second air tank 22 is slowed down. In this process, the water temperature rises slightly. During power generation, the heat exchange strengthening device is started to increase the temperature of the first air tank 21 and the second air tank 22. When the air in the first air tank 21 expands, the air pressure and temperature decrease. In this process, the first lower water pump 71 is started to pass water into the first lower spiral pipe in the first air tank 21 to supplement the heat absorbed when the air expands, and the air temperature decrease rate in the first air tank 21 is slowed down. When the air in the second air tank 22 expands, the air pressure and temperature decrease, and the second lower water pump 73 is started to pass water into the second lower spiral pipe in the second air tank 22 to supplement the heat absorbed when the air expands, and the air temperature decrease rate and amplitude in the second air tank 22 are slowed down.

[0105] Specific implementation method three: combined with Fig. 2The water pressure type compressed air hybrid energy storage power generation system of the embodiment is provided with three-stage piston compressors, the second piston compressor 12, the first piston compressor 11 and the piston compressor 1 are sequentially connected in series, and air is stored in the first gas storage tank 21 and the second gas storage tank 22 after being compressed by the second piston compressor 12, the first piston compressor 11 and the piston compressor 1 in sequence. In the embodiment, the seventeenth valve 917 is added after the first piston compressor 11, the eighteenth valve 918 is added after the second piston compressor 12, the expander 5 is connected with the first expander 51, the first expander 51 is connected with the second expander 52, and the air discharged from the liquid piston 31 and the liquid piston 32 is expanded and does work by the expander 5, the first expander 51 and the second expander 52 and then discharged to the external environment.

[0106] Specific implementation four: in combination Fig. 3 The water pressure type compressed air hybrid energy storage power generation system of the embodiment is provided with three-stage piston compressors, the second piston compressor 12, the first piston compressor 11 and the piston compressor 1 are sequentially connected in series, and air is stored in the first gas storage tank 21 and the second gas storage tank 22 after being compressed by the second piston compressor 12, the first piston compressor 11 and the piston compressor 1 in sequence. In the embodiment, the seventeenth valve 917 is added after the first piston compressor 11, the eighteenth valve 918 is added after the second piston compressor 12, the expander 5 is connected with the first expander 51, the first expander 51 is connected with the second expander 52, and the air discharged from the liquid piston 31 and the liquid piston 32 is expanded and does work by the expander 5, the first expander 51 and the second expander 52 and then discharged to the external environment.

[0107] It should be noted that, in the above embodiments, any non-contradictory technical solution can be arranged and combined, and those skilled in the art can exhaust all possibilities according to the mathematical knowledge of arrangement and combination, so that the technical solutions after arrangement and combination are not described one by one, but it should be understood that the technical solutions after arrangement and combination have been disclosed by the present application.

[0108] The above only describes the preferred embodiments of the present application and is not used to limit the present application. Those skilled in the art can make various changes and modifications to the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A water pressure type compressed air hybrid energy storage power generation system, characterized by: The compressed expansion mechanical module, the storage module and the power generation module are included. The compressed expansion mechanical module is used for compressing gas and delivering the compressed gas to the storage module. The storage module is used for receiving the gas from the compressed expansion mechanical module to store energy and delivering the stored energy to the power generation module. The power generation module is used for converting the energy stored in the storage module into electric energy. The compressed expansion mechanical module includes a piston compressor (1) and an expander (5), the piston compressor (1) includes a piston cavity and a piston, the piston is slidably arranged in the piston cavity, the piston compressor (1) is connected with the storage module, and the expander (5) is connected with the power generation module. The storage module includes a first gas storage tank (21), a second gas storage tank (22) and a heat exchange device, the outlet of the piston compressor (1) is connected with the inlet of the first gas storage tank (21), the outlet of the first gas storage tank (21) is connected with the inlet and outlet of the second gas storage tank (22), the outlet of the first gas storage tank (21) and the inlet and outlet of the second gas storage tank (22) are connected with the power generation module, and the first gas storage tank (21) and the second gas storage tank (22) are connected with the heat exchange device. The storage module further includes a first pressure sensor (81) and a second pressure sensor (82), the first pressure sensor (81) is installed in the first gas storage tank (21), and the second pressure sensor (82) is installed in the second gas storage tank (22). The energy storage working condition includes a common energy storage condition of the first gas storage tank (21) and the second gas storage tank (22) and a single energy storage condition of the first gas storage tank (21). The common energy storage condition of the first gas storage tank (21) and the second gas storage tank (22) includes: The single energy storage condition of the first gas storage tank (21) includes: The fifth valve (911) is opened; the piston compressor (1) runs in the piston up and piston down situation, and constantly charges the compressed air to the first gas tank (21) and the second gas tank (22) to store energy; with the continuous progress of the energy storage process, the air pressure in the first gas tank (21) and the second gas tank (22) is rising, when the average value of the pressure measured by the first pressure sensor (81) and the second pressure sensor (82) reaches the set pressure p 1, the seventh valve (909) is closed, and the situation of the first gas tank (21) and the second gas tank (22) storing energy together ends; The power generation stage includes a first liquid piston (31) intake condition, a second liquid piston (32) intake condition and a first gas storage tank (21) to second gas storage tank (22) air supplement condition. The piston compressor (1) continues to run in the piston upstroke and piston downstroke processes, compressing air into the first air tank (21) to store energy; as air continuously enters the first air tank (21), the air pressure in the first air tank (21) continuously rises; when the air pressure measured by the first pressure sensor (81) reaches the set pressure p 2, the energy storage of the first air tank (21) alone ends, the piston compressor (1) stops, and the fifth valve (911) is closed; The first liquid piston (31) intake condition includes: Air in the second gas storage tank (22) expands and enters the first liquid piston (31), water at the bottom of the first liquid piston (31) is squeezed out to the hydraulic generator set (4) to generate power, and the water after power generation returns to the second liquid piston (32), air at the top of the second liquid piston (32) is squeezed out to the expander (5) to generate power, and the gas after power generation returns to the external environment; when the water level in the first liquid piston (31) reaches the lower limit water level, the second liquid piston (32) intake condition is switched to; The second liquid piston (32) intake condition includes: Air in the second gas storage tank (22) expands and enters the second liquid piston (32), water at the bottom of the second liquid piston (32) is discharged to the hydraulic generator set (4) to generate power and then returns to the first liquid piston (31), air at the top of the first liquid piston (31) is squeezed out to the expander (5) to generate power and then returns to the external environment; when the water level in the second liquid piston (32) reaches the lower limit water level, the first liquid piston (31) intake condition is switched to; The first gas storage tank (21) to second gas storage tank (22) air supplement condition includes: ​ When the air pressure in the second air tank (22) drops to p 0, the first air tank (21) enters the air supplementing situation to the second air tank (22). ​ The seventh valve (909) is opened, the air in the first air tank (21) flows to the second air tank (22), the air pressure in the second air tank (22) rises, when the air pressure in the second air tank (22) rises to the set pressure p 1, the air charging process is ended, and the process of continuously charging the first liquid piston (31) and the second liquid piston (32) is continued; During the air supplement process, the air pressure in the first air tank (21) decreases. After several air supplement operations, when the pressure value measured by the first pressure sensor (81) decreases to p 1, the seventh valve (909) is always open, and the air in the first air tank (21) and the second air tank (22) expands and does work together; after the pressure values measured by the first pressure sensor (81) and the second pressure sensor (82) are both less than p 0, the power generation process ends. The storage module comprises a first gas tank (21), a second gas tank (22), a first lower water pump (71), a first upper water pump (72), a second lower water pump (73), a second upper water pump (74) and a seventh valve (909); wherein the first gas tank (21) and the second gas tank (22) are connected by a pipeline; a spiral pipeline is installed in the upper part and the lower part of the first gas tank (21); the pipeline in the lower part is connected with the first lower water pump (71) for passing in normal temperature water to cool the air; the pipeline in the upper part is connected with the first upper water pump (72) for passing in heated water to heat the air; a spiral pipeline is installed in the upper part and the lower part of the second gas tank (22); the pipeline in the lower part is connected with the second lower water pump (73) for passing in normal temperature water to cool the air; the pipeline in the upper part is connected with the second upper water pump (74) for passing in heated water to heat the air; the outlet of the first gas tank (21) is provided with the seventh valve (909) between the inlet and the outlet of the second gas tank (22); The power generation module comprises a first liquid piston (31), a second liquid piston (32) and a hydraulic generator set (4); the upper inlet of the first liquid piston (31) and the upper inlet of the second liquid piston (32) are connected with the storage module; the upper outlet of the first liquid piston (31) and the upper outlet of the second liquid piston (32) are connected with the expander (5); the lower outlet of the first liquid piston (31) is connected with the lower inlet of the second liquid piston (32) through the hydraulic generator set (4); the lower inlet of the first liquid piston (31) is connected with the lower outlet of the second liquid piston (32) through the hydraulic generator set (4); The compression and expansion mechanical module further comprises a fifth valve (911); the fifth valve (911) is arranged on the pipeline between the outlet of the piston compressor (1) and the inlet of the first gas tank (21).

2. A water pressure type compressed air hybrid energy storage power generation system according to claim 1, characterized in that: The power generation module further comprises a first gas bag accumulator (61), a second gas bag accumulator (62), a first valve (901), a second valve (902), a third valve (903) and a fourth valve (904), one end of the hydraulic generator set (4) is connected with a first opening of a first three-way pipe, a lower outlet of the first liquid piston (31) is connected with a second opening of the first three-way pipe through the second valve (902), the first gas bag accumulator (61) is arranged between the lower outlet of the first liquid piston (31) and the second valve (902), a lower outlet of the second liquid piston (32) is connected with a third opening of the first three-way pipe through the first valve (901), the second gas bag accumulator (62) is arranged between the lower outlet of the second liquid piston (32) and the first valve (901), the other end of the hydraulic generator set (4) is connected with a first opening of a second three-way pipe, a lower inlet of the first liquid piston (31) is connected with a second opening of the second three-way pipe through the third valve (903), a lower inlet of the second liquid piston (32) is connected with a third opening of the second three-way pipe through the fourth valve (904).

3. A water pressure type compressed air hybrid energy storage power generation system according to claim 2, characterized in that: The compression expansion mechanical module further comprises a sixth valve (912), and the sixth valve (912) is arranged on an inlet pipeline of the piston compressor (1); The storage module further comprises an eighth valve (910), one end of a first connecting pipe is connected with an outlet of the first gas tank (21), a middle part of the first connecting pipe is connected with an inlet and outlet of a second gas tank (22), the other end of the first connecting pipe is connected with a first opening of a third three-way pipe, and the eighth valve (910) is arranged between the inlet and outlet of the second gas tank (22) and the first opening of the third three-way pipe; The power generation module further comprises a ninth valve (905), a tenth valve (906), an eleventh valve (907) and a twelfth valve (908), the second opening of the third three-way pipe is connected with the upper inlet of the first liquid piston (31), the third opening of the third three-way pipe is connected with the upper inlet of the second liquid piston (32), the eleventh valve (907) is arranged between the second opening of the third three-way pipe and the upper inlet of the first liquid piston (31), the twelfth valve (908) is arranged between the third opening of the third three-way pipe and the upper inlet of the second liquid piston (32), the upper outlet of the first liquid piston (31) is provided with the ninth valve (905), the upper outlet of the second liquid piston (32) is provided with the tenth valve (906), one end of a second connecting pipe is connected with the tenth valve (906), a middle part of the second connecting pipe is connected with the ninth valve (905), and the other end of the second connecting pipe is connected with the expander (5).

4. A water pressure type compressed air hybrid energy storage power generation system according to claim 3, characterized in that: The power generation module further comprises a third pressure sensor (83) and a fourth pressure sensor (84), the third pressure sensor (83) is arranged in the first liquid piston (31), and the fourth pressure sensor (84) is arranged in the second liquid piston (32).

5. A method for operating a water-hydraulic compressed air hybrid energy storage power generation system, characterized in that: The water pressure type compressed air mixed energy storage power generation system of claim 3 or 4 comprises the following steps: The water pressure type compressed air mixed energy storage power generation system of claim 3 or 4 comprises the following steps: Pressure presetting process: In the pressure presetting process, the seventh valve (909) is kept open; the working conditions of the pressure presetting process include: the piston upgoing situation and the piston downgoing situation; Piston upgoing situation: When the piston upgoes, the sixth valve (912) is closed, the piston in the piston compressor (1) is pushed to move upward, the water body in the piston cavity is pushed to move upward, and the air is compressed; when the air pressure is consistent with the air pressure in the first air tank (21), the fifth valve (911) is opened, and the air in the piston compressor (1) cavity is discharged into the first air tank (21) and the second air tank (22); when the piston in the piston compressor (1) reaches the highest point, the fifth valve (911) is closed, and the piston downgoing situation is switched; Piston downgoing situation: When the piston downgoes, the sixth valve (912) is opened, the piston in the piston compressor (1) moves downward, the air volume in the piston cavity increases, and under the action of negative pressure, the outside air is sucked into the piston cavity; when the piston runs to the lowest point, the sixth valve (912) is closed, and the piston upgoing situation is switched; The piston down and up processes are repeated a plurality of times, and when the average values of the pressures measured by the first pressure sensor (81) and the second pressure sensor (82) reach the set pressure p 0, the piston compressor (1) is stopped, the fifth valve (911) is closed, and the pressure presetting process is ended.

6. The method of claim 5, wherein the water pressure type compressed air hybrid energy storage power generation system is operated as follows: When storing energy, start the heat exchange device to absorb and store the heat generated during air compression, reduce the air temperature in the first air tank (21) and the second air tank (22); when generating electricity, start the heat exchange device to heat the air by using the stored heat, and increase the air temperature in the first air tank (21) and the second air tank (22).

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