Compressed air piston hydraulic gravity energy storage system and method

Abstract

The invention discloses a compressed air piston hydraulic gravity energy storage system and method.In the system, a cooler set is arranged in the air compression energy storage system, a hot side outlet of the cooler set is connected with a high-pressure air tank set, a hot storage tank is arranged at a cold side outlet of the cooler set, and a preset heater is arranged at an outlet of a piston water gravity energy storage and release system; a high-pressure air outlet of the preset heater and an outlet of the high-pressure air tank group are connected with a working medium inlet of the air expansion energy release system, a heater group is arranged in the air expansion energy release system, and a hot side inlet of the heater group is connected with a hot storage tank; a hot side outlet of the heater group is connected with the cold storage tank, an outlet of the cold storage tank is connected with a hot side inlet of the preset heater, and a hot side outlet of the preset heater is connected with a cold side inlet of the cooler group; a water inlet / outlet of the piston water gravity energy storage and release system is connected with a reservoir through a water pump and a hydraulic turbine set; gradient utilization of pressure potential energy and kinetic energy of water can be achieved, the arrangement and installation flexibility of the energy storage system is improved, and the utilization and conversion efficiency of energy is improved.

Description

Technical Field

[0001] The invention belongs to the field of physical energy storage, and relates to a compressed air piston hydraulic gravity energy storage system and method. Background Art

[0002] With the increasing attention paid to the environmental problems and limited resources brought by traditional fossil energy, renewable energy, such as solar energy and wind energy, has been vigorously developed worldwide. However, these energy sources are intermittent and volatile. New energy storage technologies can store energy when there is excess energy and release it when there is insufficient energy, thereby effectively regulating the stability of energy supply and enabling renewable energy to be better integrated into the power grid.

[0003] Currently, compressed air energy storage systems and pumped storage systems are both relatively mature large-scale energy storage technologies. Both play a significant role in alleviating the volatility and intermittency problems currently faced in the renewable energy power generation process.

[0004] Gravity energy storage, as a new type of energy storage technology, has a very broad development prospect. Pumped storage, as a type of gravity energy storage, has the advantages of high energy conversion efficiency, large energy storage capacity and long energy storage time, but it has high construction costs and strict requirements on geographical location.

[0005] At present, the combined energy storage of compressed air system and insulation system has gradually come into people's vision. This energy storage method recycles the heat generated in the process of compressing and expanding air, which greatly improves the overall efficiency and energy utilization of the system. At the same time, the new energy storage method of compressed air energy storage combined with gravity energy storage has a good development prospect. For example, gravity blocks are used to compress air, and the compressibility of air is used to control the rise and fall of gravity blocks. The gravity blocks drive the motor to rotate to achieve the purpose of power generation. However, due to the heat energy generated and lost in the process of air compression and expansion, this energy storage method still has some disadvantages.

[0006] Currently, there is an urgent need for a new energy storage method that addresses the shortcomings of the above energy storage methods. Summary of the invention

[0007] The purpose of the present invention is to provide a compressed air piston hydraulic gravity energy storage system and method to solve the problems of low energy conversion efficiency and short energy storage time in traditional gravity energy storage systems.

[0008] In order to achieve the above-mentioned purpose, the present invention adopts the following technical scheme: a compressed air piston hydraulic gravity energy storage system, including an air compression energy storage system, an air expansion energy release system and a piston water gravity energy storage and release system; a cooler group is arranged in the air compression energy storage system, the hot side outlet of the cooler group is connected to the high-pressure gas tank group, the cold side outlet of the cooler group is arranged with a hot storage tank, the outlet of the piston water gravity energy storage and release system is arranged with a pre-set heater, the high-pressure air outlet of the pre-set heater and the outlet of the high-pressure gas tank group are connected to the working medium inlet of the air expansion energy release system, the high-pressure air outlets of the air compression energy storage system and the piston water gravity energy storage and release system are connected to the working medium inlet of the air expansion energy release system, a heater group is arranged in the air expansion energy release system, the hot side inlet of the heater group is connected to the hot storage tank, and the cold side inlet of the heater group is used as the working medium inlet; the hot side outlet of the heater group is connected to the cold storage tank, the outlet of the cold storage tank is connected to the hot side inlet of the pre-set heater, and the hot side outlet of the pre-set heater is connected to the cold side inlet of the cooler group; the water inlet and outlet of the piston water gravity energy storage and release system are connected to the water reservoir through a water pump and a turbine group.

[0009] Furthermore, the air expansion energy release system includes a cold side of a pre-set heater, a high-pressure expander, a cold side of an intermediate heater and a low-pressure expander connected along the flow direction of the working fluid, a hot side inlet of the intermediate heater is connected to the outlet of the heat storage tank, a hot side outlet of the intermediate heater is connected to the hot side inlet of the pre-set heater, and a hot side outlet of the pre-set heater is connected to the inlet of the pre-set heater.

[0010] Furthermore, the air compression energy storage system includes a low-pressure compressor and a high-pressure compressor, the cooler group includes an intercooler and an aftercooler, the low-pressure compressor, the hot side of the intercooler, the high-pressure compressor and the hot side of the aftercooler are connected in sequence along the medium flow direction, the hot side outlet of the aftercooler is connected to the high-pressure gas tank and the high-pressure gas tank; the cold side outlet of the intercooler is connected to the heat storage tank, and the cold side inlet of the aftercooler is connected to the hot side outlet of the pre-heater.

[0011] Furthermore, the piston water gravity energy storage and release system includes a piston, a gravity well, a water pump, a turbine, and a water reservoir; the piston divides the gravity well into two parts, an air compartment and a liquid compartment, the air compartment of the gravity well is connected to a compressed air system, and the liquid compartment of the gravity well is connected to a water reservoir via a water pump and a water turbine unit.

[0012] Furthermore, a plurality of nozzles are arranged at the top of the air chamber of the gravity well, and the water reservoir is connected to the nozzles.

[0013] Furthermore, the air chamber outlet of the gravity well is connected to a water vapor separator, the gas outlet of the water vapor separator is connected to a cold side inlet of a preset heater, and the water outlet of the water vapor separator is connected to a water reservoir.

[0014] Furthermore, the piston is made of iron ore, the gravity well is made of stainless steel or reinforced concrete, and the inner wall of the gravity well is a smooth surface; an O-ring is used to seal the piston and the inner wall of the gravity well, and pressure sensors and temperature sensors are installed inside the gravity well, the high-pressure gas tank and the high-pressure gas tank.

[0015] Furthermore, the reservoir is a natural lake or an artificial reservoir. The present invention also provides an operating method of the compressed air piston hydraulic gravity energy storage system, comprising: The air compression energy storage system compresses air to generate heat energy and high-pressure air. The heat energy is stored in the hot storage tank through the cooler group, and the high-pressure air is stored in the high-pressure gas tank group. The medium in the hot storage tank is stored in the cold storage tank after releasing heat. The water in the water reservoir enters the piston water gravity energy storage and release system to push the piston to compress the air in the piston water gravity energy storage and release system to generate high-pressure air; The high-pressure air of the piston water gravity energy storage and release system absorbs heat in the preset heater, enters the air expansion energy release system, expands and performs work, and then is discharged to the external environment; the high-pressure air of the high-pressure gas tank group enters the air expansion energy release system, expands and performs work, and then is discharged to the external environment; the water in the reservoir enters the piston water gravity energy storage and release system, and the piston water gravity energy storage and release system operates at a constant pressure during the compressed air energy release process; the water in the piston water gravity energy storage and release system is discharged into the reservoir to push the turbine to perform work and release energy; the high-pressure air of the high-pressure gas tank group enters the piston water gravity energy storage and release system to replenish air, and the piston water gravity energy storage and release system operates at a constant pressure; The high-pressure air in the high-pressure gas tank group and the high-pressure air after absorbing heat enter the heater group to absorb heat and then expand to do work.

[0016] Furthermore, the piston water gravity energy storage and release system includes a piston, a gravity well, a water pump, a water turbine, and a water reservoir; the piston divides the gravity well into two parts, an air compartment and a liquid compartment, the air compartment of the gravity well is connected to the compressed air system, and the liquid compartment of the gravity well is connected to the water reservoir via a water pump and a water turbine unit; a plurality of nozzles are arranged on the top of the air compartment of the gravity well, and the water reservoir is connected to the nozzles; the air compartment outlet of the gravity well is connected to a water vapor separator, the gas outlet of the water vapor separator is connected to the cold side inlet of the preset heater, and the water outlet of the water vapor separator is connected to the water reservoir; After the air pressure of the high-pressure gas tank group reaches the set value, water is pumped from the water reservoir to the liquid tank of the gravity well, the air in the air tank is compressed, and the water pump is driven to supply water to the nozzle for spraying to cool the compressed air. After the air pressure in the air tank reaches the set value, the high-pressure air passes through the water vapor separator for gas-water separation, and then the high-pressure air enters the preset heater and the water enters the water reservoir.

[0017] The operation of the compressed air piston hydraulic gravity energy storage system specifically includes the pre-compression process, energy storage process and energy release process; Energy storage process: air enters the low-pressure compressor through the pressure pipe, enters the high-pressure compressor through the intercooler, and then flows into the aftercooler and enters the high-pressure gas tank. When the high-pressure gas tank and air pressure reach the target value, the water pump is driven to pump water from the reservoir to the liquid tank of the gravity well, thereby achieving the purpose of lifting the piston, thereby compressing the air tank of the gravity well, and at the same time driving the water pump to supply water to the nozzle for spraying to reduce the temperature of the compressed air in the air tank. When the air pressure in the air tank reaches the target value, the valve is opened, and the high-pressure air passes through the water vapor separator and enters the aftercooler for secondary heat exchange. Finally, the gas is discharged into the expansion system to drive the high-pressure expander and the low-pressure expander to do work. At this time, the piston rises to the specified height in the gravity well. At this point, the energy storage process of the device ends.

[0018] The liquid in the water vapor separator will be pumped into the water reservoir through a water pump. In addition, the compressed air in the gravity well air tank does not need to do work in the expansion system at this stage, but can be directly stored in the high-pressure gas tank and in order to ensure the constant pressure operation of the piston water gravity system during the energy release process.

[0019] Energy release process: First, the piston in the gravity well relies on its own gravitational potential energy to push the water through the turbine to do work, and store the water in the reservoir. During the piston's fall, the high-pressure gas tank replenishes air to the air tank to ensure constant pressure operation inside the gravity well, and the piston can fall steadily. When the piston drops to the specified height, the energy release process of the piston water gravity system is completed. Then the compressed air in the high-pressure gas tank is released through the pressure pipe, enters the air expansion system to do work on the high-pressure expander and the low-pressure expander, and finally releases the air after work into the atmosphere. At this point, the energy release process ends.

[0020] Compared with the prior art, the present invention has the following beneficial effects: The present invention further utilizes the heat generated by the compressed air in the air expansion process based on the compressed air system, and reuses the cold generated by the air expansion in the compressed air cooling process, thereby realizing the step-by-step utilization of heat and effectively improving the working efficiency of the energy storage system; the present invention combines the air compression system based on the gravity energy storage system, and the two work together to provide a new idea for the joint storage of two clean energy sources and the conversion of energy, which is of great significance for achieving clean, efficient, long-term and large-scale energy storage; the present invention uses pressure control measures to enable the system to maintain stable operation under re-energy storage and energy release conditions, and has good stability; the operation of the present invention does not generate additional greenhouse gases such as carbon dioxide, and the impact on the environment can be ignored, which is conducive to achieving sustainable development; the energy storage system of the present invention has strong environmental adaptability and has good economic benefits whether in mountains, plateaus or plains.

[0021] Furthermore, the air compressed by the low-pressure compressor undergoes heat exchange in the intercooler and then enters the inlet of the high-pressure compressor through the pressure pipe. The high-pressure gas generated in the high-pressure compressor enters the aftercooler through the pressure pipe and undergoes heat exchange, and then is stored in the high-pressure gas tank group through the pressure pipe, and the heat is stored in the heat storage tank.

[0022] Furthermore, the inlet of the high-pressure expander is connected to the pre-set heater and the high-pressure gas tank through a pressure pipe, and the outlet is connected to the intermediate heater and the low-pressure expander. After the compressed air is released from the high-pressure gas tank, heat exchange occurs in the pre-set heater, and then enters the high-pressure expander through the pressure pipe to exchange heat with the intermediate heater, and then enters the low-pressure expander and enters the atmosphere through the pressure pipe, thereby improving the work efficiency of the compressed air.

[0023] Furthermore, the reservoir is replaced by a natural lake or an artificial reservoir, which greatly reduces the construction cost and makes it easy to achieve a larger scale.

[0024] Furthermore, a nozzle connected to a water pump is provided in the air chamber of the gravity well to cool the compressed air in the air chamber.

[0025] Furthermore, during the compression process of the gravity well air chamber, the water pump will supply water to the nozzle for spraying to lower the temperature of the air chamber, and the compressed water vapor will re-enter the water reservoir through the water vapor separator; during the energy release process, the high-pressure gas tank and will replenish air to maintain a constant pressure state in the chamber. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a structural schematic diagram of a compressed air piston hydraulic gravity energy storage system of the present invention.

[0027] Figure 2 It is a partial schematic diagram of the gravity well of the present invention.

[0028] In the figure, 1-low-pressure compressor, 2-high-pressure compressor, 3-low-pressure expander, 4-high-pressure expander, 5-first high-pressure gas tank, 6-second high-pressure gas tank, 7-piston, 8-hot storage tank, 9-cold storage tank, 10-intermediate cooler, 11-aftercooler, 12-intermediate heater, 13-pre-heater, 14-pre-heater, 15-water vapor separator, 16-water reservoir, 17-water pump, 18-water pump, 19-water pump, 20-turbine, 21-nozzle, 22-pressure sensor, 23-gravity well, 24-piston wall, 25-O-ring, 26-stainless steel wall. DETAILED DESCRIPTION

[0029] The technical solutions 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, rather than all of the embodiments. Based on the embodiments in 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. The terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features.

[0030] The technical concept of the present invention is as follows: a compressed air piston hydraulic gravity energy storage system; including an air compression energy storage system, an air expansion energy release system and a piston water gravity energy storage and release system; a cooler group is arranged in the air compression energy storage system, the hot side outlet of the cooler group is connected to the high-pressure gas tank group, and the cold side outlet of the cooler group is arranged with a hot storage tank 8, and the outlet of the piston water gravity energy storage and release system is arranged with a pre-set heater 14, and the high-pressure air outlet and the high-pressure gas tank group outlet of the pre-set heater 14 are connected to the working medium inlet of the air expansion energy release system, and the high-pressure air outlets of the air compression energy storage system and the piston water gravity energy storage and release system are connected to the working medium inlet of the air expansion energy release system; a heater group is arranged in the air expansion energy release system, the hot side inlet of the heater group is connected to the hot storage tank 8, and the cold side inlet of the heater group is used as the working medium inlet; the hot side outlet of the heater group is connected to the cold storage tank 9, and the outlet of the cold storage tank 9 is connected to the hot side inlet of the pre-set heater 14, and the hot side outlet of the pre-set heater 14 is connected to the cold side inlet of the cooler group; the water inlet and outlet of the piston water gravity energy storage and release system are connected to the water reservoir 16 through a water pump and a turbine group.

[0031] When the system is running, the air compression energy storage system compresses air to generate heat energy and high-pressure air. The heat energy is stored in the hot storage tank 8 through the cooler group, and the high-pressure air is stored in the high-pressure gas tank group. The medium of the hot storage tank 8 is stored in the cold storage tank 9 after releasing heat; the water in the water reservoir 16 enters the piston water gravity energy storage and release system to push the piston to compress the air in the piston water gravity energy storage and release system to generate high-pressure air; the high-pressure air of the piston water gravity energy storage and release system enters the air expansion energy release system after absorbing heat from the preset heater 14, and is discharged to the external environment after expansion and work; the high-pressure gas tank The high-pressure air of the group enters the air expansion energy release system, expands and performs work, and then is discharged to the external environment; the water in the water reservoir 16 enters the piston water gravity energy storage and release system, and the piston water gravity energy storage and release system operates at a constant pressure during the compressed air energy release process; the water in the piston water gravity energy storage and release system is discharged into the water reservoir 16, and in the process of pushing the turbine to perform work and release energy; the high-pressure air of the high-pressure gas tank group enters the piston water gravity energy storage and release system to replenish air, and the piston water gravity energy storage and release system operates at a constant pressure; the high-pressure air of the high-pressure gas tank group and the high-pressure air after absorbing heat enter the heater group, absorb heat, and then expand and perform work.

[0032] Embodiment 1, Figure 1 The example is a compressed air piston hydraulic gravity energy storage system, including a compressed air energy storage system, an air expansion energy release system, a water gravity energy storage system containing a piston, and a heat circulation system.

[0033] The compressed air energy storage system includes a low-pressure compressor 1, a high-pressure compressor 2, a first high-pressure gas tank 5 and a second high-pressure gas tank 6; the inlet of the low-pressure compressor 1 is connected to the atmosphere, and the gas generated by the low-pressure compressor 1 enters the inlet of the high-pressure compressor 2 after heat exchange through the intermediate cooler 10; the high-pressure air generated by the high-pressure compressor 2 enters the first high-pressure gas tank 5 and the second high-pressure gas tank 6 through a pipeline after heat exchange pressure through the aftercooler 11 to be stored.

[0034] The air expansion energy release system includes a low-pressure expander 3 and a high-pressure expander 4. The high-pressure gas from the air bin in the gravity well 23 and the compressed gas in the first high-pressure gas tank 5 and the second high-pressure gas tank 6 respectively enter the air expansion energy release system after heat exchange in the preset heater 14 and the preset heater 13. The gas first enters the high-pressure expander 4 through a pressure pipeline. The gas after expansion and work enters the intermediate heater 12 for heat exchange and then is sent to the low-pressure expander 3 to expand and do work, and is discharged into the atmosphere through a pipeline.

[0035] The heat circulation system includes an intercooler 10, an aftercooler 11, a pre-heater 13, an interheater 12, a hot storage tank 8 and a cold storage tank 9. The intercooler 10, the aftercooler 11 and the pre-heater 14 are connected to the hot storage tank 8. The interheater 12 and the pre-heater 13 are connected between the hot storage tank 8 and the cold storage tank 9, so that the heat generated in the compression system can be utilized in the expansion system.

[0036] The water gravity energy storage system containing a piston includes a gravity well 23, a piston 7, a water pump 17, a water pump 18, a water pump 19, a water turbine 20, a water reservoir 16, a nozzle 21, and a water vapor separator 15. The piston 7 is placed inside the gravity well 23 to divide the gravity well 23 into two parts, the upper part is an air tank, and the lower part is a liquid tank. The liquid tank of the gravity well 23 is connected to the water reservoir 16 through a pressure pipe together with the water pump and the water turbine. The air tank is connected to the water vapor separator 15 through a pressure pipe. The gas outlet of the water vapor separator 15 is connected to the gas inlet of 14, and is further incorporated into the compressed air system.

[0037] As a further optimization, a plurality of nozzles are arranged at the top of the air chamber of the gravity well 23, and the water reservoir 16 is connected to the nozzles, so as to cool down the compressed air in the air chamber.

[0038] The air bin outlet of the gravity well 23 is connected to the water vapor separator 15, the gas outlet of the water vapor separator 15 is connected to the cold side inlet of the preset heater 14, and the water outlet of the water vapor separator 15 is connected to the water reservoir 16; during the compression process of the gravity well air bin, the water pump will supply water to the nozzle for spraying to reduce the temperature of the air bin, and the compressed water vapor will re-enter the water reservoir through the water vapor separator; during the energy release process, the high-pressure gas tank and will replenish air to maintain a constant pressure state in the bin.

[0039] Furthermore, the piston 7 is made of iron ore, the gravity well 23 is made of stainless steel or reinforced concrete, and the inner wall of the gravity well 23 is a smooth surface; the piston 7 and the inner wall of the gravity well 23 are sealed with an O-ring, and pressure sensors and temperature sensors are installed inside the gravity well 23, the high-pressure gas storage tank 5, and the high-pressure gas storage tank 6. The inner wall of the gravity well 23 can be made of stainless steel, and an O-ring 25 is arranged between the piston wall 24 and the stainless steel wall.

[0040] Embodiment 2, a method for operating a compressed air piston hydraulic gravity energy storage system of the present invention, comprising: Energy storage process: Open the first valve 101 on the pressure pipeline of the compression system, and air at normal temperature and pressure enters the low-pressure compressor 1 for compression. At this time, the temperature and pressure of the air increase. After heat exchange in the intercooler 10, the air enters the high-pressure compressor 2 for a second compression. The pressure and temperature of the air further increase. After cooling in the aftercooler 11, the air is stored in the first high-pressure gas tank 5. When the pressure sensor 22 in the first high-pressure gas tank 5 detects that the pressure in the gas tank reaches the target value, the second valve 102, the third valve 103, and the fourth valve 104 are opened to allow additional gas to be transported to the second high-pressure gas tank 6 through the pressure pipeline. When the pressure in the second high-pressure gas tank 6 reaches the target value, the second valve 102 and the first valve 101 are closed, and the low-pressure compressor 1 and the high-pressure compressor 2 stop working. The eighth valve 108 and the ninth valve 109 are opened, and the water pump 19 delivers the water in the water reservoir 16 to the water tank of the gravity well 23. At the same time, the piston 7 is lifted up, and the volume of the air tank in the gravity well is reduced. When the air therein is compressed to the target pressure value, the tenth valve 1010 is opened, and the water pump 17 delivers the water in the water reservoir 16 to the air tank through the nozzle 21 to cool the high-pressure air. Then, the sixth valve 106 is opened, and the high-pressure air passes through the water vapor separator 15 and the aftercooler 14 and enters the expansion system to perform work. At this time, there are two options. On the one hand, the fifth valve 105 can be opened to directly drive the high-pressure expander 4 and the low-pressure expander 3 to perform work and generate electricity. On the other hand, the air in the gravity well 23 can be discharged into the first high-pressure gas tank 5 and the second high-pressure gas tank 6 to wait for the opportunity to perform work and generate electricity.

[0041] Energy release process: When the power grid is at its peak, the system needs to generate power. At this time, the seventh valve 107, the ninth valve 109, the sixth valve 106, the fourth valve 104, the third valve 103, and the second valve 102 are opened, and the piston 7 descends. The water in the water tank enters the turbine 20 through the pressure pipe to perform work, and is then discharged into the reservoir 16. At the same time, the first high-pressure gas tank 5 and the second high-pressure gas tank 6 discharge compressed air through the pressure pipe into the piston gravity energy storage system to fill the air tank of the gravity well 23 to ensure that the piston 7 descends stably. When it drops to the set height, the seventh valve 107, the ninth valve 109, and the sixth valve 106 are closed, and the fifth valve 105 is opened. The remaining gas in the first high-pressure gas tank 5 and the second high-pressure gas tank 6 enters the preset heater 13 through the pressure pipeline for heating, and then enters the high-pressure expander 4. At this time, the air temperature decreases and the pressure drops. The air that has been expanded once enters the intermediate heater 12 for secondary heating and then enters the low-pressure expander 3 through the pressure pipeline. The air temperature decreases again, the pressure drops, and finally it is discharged into the atmosphere through the pressure pipeline. At this point, the energy release process of the entire device ends and enters the next cycle again.

[0042] The present invention discloses a compressed air piston hydraulic gravity energy storage system and method, the system includes a compressed air energy storage system, an air expansion energy release system, a water gravity energy storage system containing a piston, and a heat circulation system. The compressed air energy storage system includes a low-pressure compressor, a high-pressure compressor, and a high-pressure gas tank; the air expansion energy release system includes a low-pressure expander, a high-pressure expander, and a high-pressure gas tank; the piston hydraulic gravity energy storage system includes a gravity well, a piston, a water pump, a water turbine, a water reservoir, a nozzle, and a water vapor separator. The gravity well is divided into an air bin and a water bin by the piston. The air bin is connected to the air compression system, and the water bin is connected to the water turbine and the water pump; the heat circulation system includes an intermediate cooler, an aftercooler, a pre-set heater, an intermediate heater, a hot storage tank, and a cold storage tank. The present invention utilizes the characteristics of compressed air and difficult-to-compress water, connects the two together through a piston system, stores the energy of compressed air in a high-pressure gas tank to drive an expander to generate electricity, and uses hydropower generation as the main means of power generation, using a piston to push water in a turbine to generate electricity, while utilizing the heat generated in the compressed air in the expansion system, thereby realizing the cascade utilization of pressure potential energy and kinetic energy of water. Compared with traditional compressed air energy storage systems and pumped storage systems, the present invention improves the flexibility of energy storage system layout and installation, and improves energy utilization and conversion efficiency, and is an effective way to achieve efficient, economical, pollution-free, large-scale, long-term energy storage.

[0043] The above contents are only for explaining the technical idea of ​​the present invention and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution in accordance with the technical idea proposed by the present invention shall fall within the protection scope of the claims of the present invention.

Claims

1. A compressed air piston hydraulic gravity energy storage system, characterized in that: The invention comprises an air compression energy storage system, an air expansion energy release system and a piston water gravity energy storage and release system; a cooler group is arranged in the air compression energy storage system, the hot side outlet of the cooler group is connected to the high-pressure gas tank group, the cold side outlet of the cooler group is arranged to the hot storage tank (8), the outlet of the piston water gravity energy storage and release system is arranged to the pre-set heater (14), the high-pressure air outlet and the outlet of the high-pressure gas tank group of the pre-set heater (14) are connected to the working medium inlet of the air expansion energy release system, a heater group is arranged in the air expansion energy release system, the hot side inlet of the heater group is connected to the hot storage tank (8), and the cold side inlet of the heater group is used as the working medium inlet; the hot side outlet of the heater group is connected to the cold storage tank (9), the outlet of the cold storage tank (9) is connected to the hot side inlet of the pre-set heater (14), and the hot side outlet of the pre-set heater (14) is connected to the cold side inlet of the cooler group; the water inlet and outlet of the piston water gravity energy storage and release system are connected to the water storage tank (16) through a water pump and a water turbine group.

2. The compressed air piston hydraulic gravity energy storage system according to claim 1 is characterized in that: The air expansion energy release system comprises a cold side of a pre-set heater (13), a high-pressure expander (4), a cold side of an intermediate heater (12), and a low-pressure expander (3) connected along the working medium flow direction; a hot side inlet of the intermediate heater (12) is connected to an outlet of a heat storage tank (8); a hot side outlet of the intermediate heater (12) is connected to a hot side inlet of a pre-set heater (13); and a hot side outlet of the pre-set heater (13) is connected to an inlet of a pre-set heater (14).

3. The compressed air piston hydraulic gravity energy storage system according to claim 1, characterized in that: The air compression energy storage system comprises a low-pressure compressor (1) and a high-pressure compressor (2); the cooler group comprises an intermediate cooler (10) and an aftercooler (11); the low-pressure compressor (1), the hot side of the intermediate cooler (10), the high-pressure compressor (2) and the hot side of the aftercooler (11) are connected in sequence along the flow direction of the medium; the hot side outlet of the aftercooler (11) is connected to a first high-pressure gas tank (5) and a second high-pressure gas tank (6); the cold side outlet of the intermediate cooler (10) is connected to a heat storage tank (8), and the cold side inlet of the aftercooler (11) is connected to the hot side outlet of a pre-heater (14).

4. The compressed air piston hydraulic gravity energy storage system according to claim 1, characterized in that: The piston water gravity energy storage and release system comprises a piston (7), a gravity well (23), a water pump (19), a water turbine (20), and a water reservoir (16); the piston (7) divides the gravity well (23) into two upper and lower parts, an air chamber and a liquid chamber; the air chamber of the gravity well (23) is connected to a compressed air system, and the liquid chamber of the gravity well (23) is connected to the water reservoir (16) via a water pump and a water turbine unit.

5. The compressed air piston hydraulic gravity energy storage system according to claim 1, characterized in that: A plurality of nozzles are arranged at the top of the air chamber of the gravity well (23), and the water reservoir (16) is connected to the nozzles.

6. The compressed air piston hydraulic gravity energy storage system according to claim 1, characterized in that: The air chamber outlet of the gravity well (23) is connected to the water vapor separator (15), the gas outlet of the water vapor separator (15) is connected to the cold side inlet of the preset heater (14), and the water outlet of the water vapor separator (15) is connected to the water reservoir (16).

7. The compressed air piston hydraulic gravity energy storage system according to claim 1, characterized in that: The piston (7) is made of iron ore, the gravity well (23) is made of stainless steel or reinforced concrete, and the inner wall of the gravity well (23) is a smooth surface; an O-ring is used to seal the piston (7) and the inner wall of the gravity well (23), and a pressure sensor and a temperature sensor are installed inside the gravity well (23), the high-pressure gas storage tank (5) and the high-pressure gas storage tank (6).

8. The compressed air piston hydraulic gravity energy storage system according to claim 1, characterized in that: The reservoir (16) is a natural lake or an artificial reservoir.

9. The operating method of the compressed air piston hydraulic gravity energy storage system according to any one of claims 1 to 8, characterized in that: include: The air compression energy storage system compresses air to generate heat energy and high-pressure air, wherein the heat energy is stored in a heat storage tank (8) through a cooler group, and the high-pressure air is stored in a high-pressure gas tank group, and the medium in the heat storage tank (8) is stored in a cold storage tank (9) after releasing heat; The water in the water reservoir (16) enters the piston water gravity energy storage and release system to push the piston to compress the air in the piston water gravity energy storage and release system to generate high-pressure air; The high-pressure air of the piston water gravity energy storage and release system absorbs heat in the pre-set heater (14), enters the air expansion energy release system, expands to do work, and then is discharged to the external environment; the high-pressure air of the high-pressure gas tank group enters the air expansion energy release system, expands to do work, and then is discharged to the external environment; the water in the water reservoir (16) enters the piston water gravity energy storage and release system, and the piston water gravity energy storage and release system operates at a constant pressure during the compressed air energy release process; the water in the piston water gravity energy storage and release system is discharged into the water reservoir (16) to drive the turbine to do work and release energy; the high-pressure air of the high-pressure gas tank group enters the piston water gravity energy storage and release system to replenish air, and the piston water gravity energy storage and release system operates at a constant pressure; The high-pressure air in the high-pressure gas tank group and the high-pressure air after absorbing heat enter the heater group to absorb heat and then expand to do work.

10. The operating method according to claim 9, characterized in that: The piston water gravity energy storage and release system comprises a piston (7), a gravity well (23), a water pump (19), a water turbine (20), and a water reservoir (16); the piston (7) divides the gravity well (23) into two upper and lower parts, an air chamber and a liquid chamber; the air chamber of the gravity well (23) is connected to a compressed air system, and the liquid chamber of the gravity well (23) is connected to the water reservoir (16) via a water pump and a water turbine unit; a plurality of nozzles are arranged at the top of the air chamber of the gravity well (23), and the water reservoir (16) is connected to the nozzles; the air chamber outlet of the gravity well (23) is connected to a water vapor separator (15), the gas outlet of the water vapor separator (15) is connected to the cold side inlet of a preset heater (14), and the water outlet of the water vapor separator (15) is connected to the water reservoir (16); When the air pressure of the high-pressure gas tank group reaches the set value, water is pumped from the water reservoir (16) into the liquid tank of the gravity well (23), the air in the air tank is compressed, and the water pump (17) is driven to supply water to the nozzle (21) for spraying to cool the compressed air. When the air pressure in the air tank reaches the set value, the high-pressure air passes through the water vapor separator (15) for air-water separation, and then enters the pre-set heater (14), and the water enters the water reservoir (16).

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