Comprehensive energy storage system based on underground cave

Abstract

The utility model discloses a comprehensive energy storage system based on an underground cave. The comprehensive energy storage system comprises the underground cave; the upper reservoir is located on the ground surface, and a water conveying pipeline is communicated between the upper reservoir and the underground cave; the pumped storage unit is arranged in the middle of the water conveying pipeline; the air compression system can be used for compressing air in the underground cave; and the spraying system is arranged at the top of the underground cave. According to the utility model, hydraulic machinery is adopted for energy conversion, the conversion efficiency is superior to that of a thermodynamic system, the system efficiency of the system is higher than that of a compressed air system and close to that of a pure pumped storage system, the advantages of high pumped storage conversion efficiency and large energy storage capacity of the compressed air system are integrated, and the system is a long-time energy storage system which can be popularized on a large scale.

Description

TECHNICAL FIELD

[0001] The utility model relates to a kind of comprehensive energy storage systems based on underground cave, belong to energy storage technology field. BACKGROUND

[0002] The artificial cave built in underground rock stratum by water-soluble mining method is called "salt cave". Because rock salt has very low permeability, good creep characteristics and damage recovery function, and salt cavity is deeply buried underground, it can self-weight crystallization healing under the condition of producing local stratum fracture, and underground cave becomes good sealing storage medium. The overall development and utilization of salt cave underground space in China is in the exploration stage, with an average burial depth of 500-2000 meters or more. According to technical conditions, the volume can reach hundreds of thousands of cubic meters, and a large amount of gas can be stored under a pressure of up to 20 megapascals according to different depths. China is rich in salt cave resources, with about 1.3x10 8 m 3 Most of them have good sealing performance after being caved, but the currently utilized salt caves only account for 0.2% of the total, and most of them are idle.

[0003] The comprehensive efficiency of traditional pumped storage power station is about 75%, and the average value of the annual power station comprehensive efficiency of more than 20 pumped storage power stations in China in 2017 is 78.63%. The project investment cost is about 5000-6000 yuan / kW. The theoretical limit efficiency of compressed air energy storage technology is about 75%, the initial investment of compressed air energy storage power station using metal container is more than 10000 yuan / kW, and the initial investment of compressed air energy storage power station using salt cave or artificial chamber is about 6000-7000 yuan / kW. The system electric-electric efficiency of non-reheat compressed air energy storage system is about 72.1%, and the cost is about 6000 yuan / kW.

[0004] In summary, the traditional pumped storage system is limited by geological site selection, and the investment cost is high, while the compressed air energy storage system uses thermodynamic conversion, and the system efficiency is low. Therefore, we propose a comprehensive energy storage system based on underground cave. UTILITY MODEL CONTENTS

[0005] The utility model aims at providing a comprehensive energy storage system based on underground cave, which uses compressed air and pumped coupling system, fully utilizes underground abandoned space, reduces investment cost, and ensures system conversion efficiency.

[0006] To solve the above technical problems, the utility model adopts the following technical scheme: a comprehensive energy storage system based on underground cave, comprising: an underground cave, which can be used as a sealed storage medium, such as artificial chamber, abandoned mine, etc., and can be artificially sealed;

[0007] An upper reservoir is located on the ground surface, which can be excavated into a reservoir or an above-ground water tank, and a water pipeline is connected between the upper reservoir and the underground cave to connect the upper reservoir and the underground cave;

[0008] A pumped storage unit is arranged in the middle of the water pipeline, which can provide power for the water flow in the water pipeline and convert the potential energy of the water flow in the water pipeline into electric energy;

[0009] An air compression system is arranged to compress the air in the underground cave;

[0010] A spraying system is arranged on the top of the underground cave to enhance the heat transfer between the high-pressure gas and water in the tank to achieve isothermal compression / expansion.

[0011] The foregoing comprehensive energy storage system based on an underground cave, the water pipeline includes a water intake pipeline and a tail water pipeline, two ends of the water intake pipeline are connected with the upper reservoir and the pumped storage unit respectively, two ends of the tail water pipeline are connected with the pumped storage unit and the underground cave respectively, the water pipeline is usually selected from steel pipe or concrete pipe, and the material selection needs to consider its pressure resistance, corrosion resistance and durability, and the pipeline length and bending should be reduced as much as possible during arrangement to reduce the hydraulic loss.

[0012] The foregoing comprehensive energy storage system based on an underground cave, the water intake pipeline and the tail water pipeline are both provided with opening and closing gates, the water intake pipeline has a certain slope to ensure the smooth flow of water, and excessive slope will cause energy loss, and the slope change of the water intake pipeline reduces the impact on the water outlet.

[0013] The foregoing comprehensive energy storage system based on an underground cave, the pumped storage unit includes a pump-turbine, the pump-turbine is connected with a generator and a motor, the pump-turbine can provide power for the generator to supply power to the external power grid, the motor can be powered by the external power grid to provide power for the pump-turbine, and two ends of the pump-turbine are connected with the water intake pipeline and the tail water pipeline respectively.

[0014] The foregoing comprehensive energy storage system based on an underground cave further includes a wind turbine generator set and a photovoltaic generator set arranged on the ground surface, and the wind turbine generator set and the photovoltaic generator set are connected with the pump-turbine.

[0015] The foregoing comprehensive energy storage system based on an underground cave, the air compression system includes a compressor and an air pipeline, the compressor is arranged on the ground surface, one end of the air pipeline is connected with the output end of the compressor, and the other end of the air pipeline is connected to the inner cavity of the underground cave.

[0016] The air pipeline is provided with an air valve near one side of the underground cave, and is provided with a pressure relief valve at the end far from the underground cave, and the pressure relief valve is connected in parallel with the compressor.

[0017] The spray system comprises a spray pipeline and a spray device, one end of the spray pipeline is connected with the water delivery pipeline, the other end of the spray pipeline extends into the inner cavity of the underground cave and is connected with the spray device, and the spray device is arranged at the top of the inner cavity of the underground cave.

[0018] The spray pipeline is provided with a spray valve and a check valve.

[0019] Compared with the prior art, the utility model has at least the following beneficial effects:

[0020] (1) The utility model adopts hydraulic machinery to convert energy, and the conversion efficiency is higher than that of a thermodynamic system, the system efficiency of the system is higher than that of a compressed air system, and is close to that of a pure pumping and storing system.

[0021] (2) The utility model combines the advantages of high pumping and storing conversion efficiency and large energy storage capacity of the compressed air system, and is a long-time energy storage system which can be popularized on a large scale.

[0022] (3) The system of the utility model has less restrictions on space site selection, can adopt underground caves, abandoned mine caves and other resources, can fully utilize the existing underground space, improves the utilization rate of the underground caves and the abandoned mine caves, and reduces the system investment cost. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 It is a system structure schematic view of the utility model.

[0024] Mark: 1-Underground cave, 2-Upper reservoir, 3-Water delivery pipeline, 31-Water diversion pipeline, 32-Tail water pipeline, 33-Open-close gate, 4-Pumping and storing unit, 41-Water pump turbine, 42-Generator, 43-Electric motor, 5-Air compression system, 51-Compressor, 52-Air pipeline, 53-Air valve, 54-Pressure relief valve, 6-Spray system, 61-Spray pipeline, 62-Spray device, 63-Spray valve, 64-Check valve, 7-Wind driven generator set, 8-Photovoltaic generator set.

[0025] The utility model will be further described below in combination with the drawings and specific embodiments. EMBODIMENT

[0026] The utility model discloses an embodiment 1: a kind of integrated energy storage system based on underground cave, comprising: underground cave 1, underground cave 1 can be used as sealed storage medium, such as artificial chamber, abandoned mine, etc., can be artificially sealed.

[0027] Upper reservoir 2, upper reservoir 2 is located on the ground, and the horizontal position is higher than underground cave 1, which can be excavated into a reservoir, or an above-ground water pool can be used, and upper reservoir 2 is communicated with underground cave 1 by water conveying pipeline 3, so that upper reservoir 2 and underground cave 1 are communicated.

[0028] Pumping storage unit 4, which is arranged in the middle of the water conveying pipeline 3, can provide power for the water flow in the water conveying pipeline 3, and can also convert the potential energy of the water flow in the water conveying pipeline 3 into electrical energy; the type of the pumping storage unit 4 depends on the effective water head difference between upper reservoir 2 and underground cave 1 (effective water head difference = actual water head difference + equivalent water head of gas pressure), when the difference is more than 800 m, the single machine of the pumping storage unit 4 can be preferably three-machine type, and when the difference is less than 800 m, the single machine of the pumping storage unit 4 can be preferably two-machine type.

[0029] Air compression system 5, which can compress the air in underground cave 1, fills the external air into underground cave 1;

[0030] Spraying system 6, which is arranged at the top of underground cave 1, is used to enhance the heat transfer between the high-pressure gas and water in the tank to realize isothermal compression / expansion.

[0031] The utility model discloses an embodiment 2: a kind of integrated energy storage system based on underground cave, comprising: underground cave 1, underground cave 1 can be used as sealed storage medium, such as artificial chamber, abandoned mine, etc., can be artificially sealed.

[0032] Upper reservoir 2, upper reservoir 2 is located on the ground, and the horizontal position is higher than underground cave 1, which can be excavated into a reservoir, or an above-ground water pool can be used, and upper reservoir 2 is communicated with underground cave 1 by water conveying pipeline 3, so that upper reservoir 2 and underground cave 1 are communicated.

[0033] Pumping storage unit 4, which is arranged in the middle of the water conveying pipeline 3, can provide power for the water flow in the water conveying pipeline 3, and can also convert the potential energy of the water flow in the water conveying pipeline 3 into electrical energy; the type of the pumping storage unit 4 depends on the effective water head difference between upper reservoir 2 and underground cave 1 (effective water head difference = actual water head difference + equivalent water head of gas pressure), when the difference is more than 800 m, the single machine of the pumping storage unit 4 can be preferably three-machine type, and when the difference is less than 800 m, the single machine of the pumping storage unit 4 can be preferably two-machine type.

[0034] The water delivery pipeline 3 includes a water inlet pipeline 31 and a tail water pipeline 32, the two ends of the water inlet pipeline 31 are connected with the upper reservoir 2 and the pumped storage unit 4 respectively, the two ends of the tail water pipeline 32 are connected with the pumped storage unit 4 and the underground cave 1 respectively, the water delivery pipeline 3 is usually selected from a steel pipe or a concrete pipe, the material selection needs to consider the pressure resistance, corrosion resistance and durability, and the pipeline length and bending should be reduced as much as possible during the arrangement to reduce the hydraulic loss, the water inlet pipeline 31 and the tail water pipeline 32 are provided with opening and closing gates 33, the water inlet pipeline 31 has a certain slope to ensure that the water can flow smoothly, and an excessive slope will cause energy loss, and the slope change of the water inlet pipeline 31 reduces the impact on the water outlet

[0035] The air compression system 5 can compress the air in the underground cave 1 and fill the external air into the underground cave 1.

[0036] The spraying system 6 is arranged on the top of the underground cave 1 and is used for enhancing the heat transfer between the high-pressure gas and water in the tank to realize the isothermal compression / expansion.

[0037] Embodiment 3 of the utility model: a comprehensive energy storage system based on an underground cave, comprising: an underground cave 1, the underground cave 1 can be used as a sealed storage medium, such as artificial chamber, abandoned mine, etc., and can be artificially sealed.

[0038] The upper reservoir 2 is located on the ground surface and has a horizontal position higher than the underground cave 1, can be excavated into a reservoir or can be used as an above-ground water tank, and the upper reservoir 2 is communicated with the underground cave 1 through the water delivery pipeline 3, so that the upper reservoir 2 and the underground cave 1 are communicated.

[0039] The pumped storage unit 4 is arranged in the middle part of the water delivery pipeline 3, can provide power for the water flow in the water delivery pipeline 3, and can also convert the potential energy of the water flow in the water delivery pipeline 3 into electric energy; the pumped storage unit 4 comprises a water pump water turbine 41, the water pump water turbine 41 is connected with a generator 42 and an electric motor 43, the water pump water turbine 41 can provide power for the generator 42 to supply power to an external power grid, the electric motor 43 can supply power to the water pump water turbine 41 through the external power grid, and the two ends of the water pump water turbine 41 are connected with the water inlet pipeline 31 and the tail water pipeline 32 respectively.

[0040] The water delivery pipeline 3 includes a water inlet pipeline 31 and a tail water pipeline 32, the two ends of the water inlet pipeline 31 are connected with the upper reservoir 2 and the pumped storage unit 4 respectively, the two ends of the tail water pipeline 32 are connected with the pumped storage unit 4 and the underground cave 1 respectively, the water delivery pipeline 3 is usually selected from a steel pipe or a concrete pipe, the material selection needs to consider the pressure resistance, corrosion resistance and durability, and the pipeline length and bending should be reduced as much as possible during the arrangement to reduce the hydraulic loss, the water inlet pipeline 31 and the tail water pipeline 32 are provided with opening and closing gates 33, the water inlet pipeline 31 has a certain slope to ensure that the water can flow smoothly, and an excessive slope will cause energy loss, and the slope change of the water inlet pipeline 31 reduces the impact on the water outlet

[0041] The air compression system 5 can compress the air in the underground cave 1 and fill the external air into the underground cave 1.

[0042] The spraying system 6 is arranged on the top of the underground cave 1 and is used for enhancing the heat transfer between the high-pressure gas and water in the tank to realize the isothermal compression / expansion.

[0043] Embodiment 4 of the utility model: a kind of comprehensive energy storage system based on underground cave, it include: underground cave 1, underground cave 1 can be used as sealed storage medium, such as artificial chamber, abandoned mine, etc., can be artificially sealed.

[0044] The upper reservoir 2 is located on the ground surface and is higher than the underground cave 1 in horizontal position, and can be excavated into a reservoir or used as an above-ground water tank, the upper reservoir 2 is communicated with the underground cave 1 through the water delivery pipeline 3, and the water delivery pipeline 3 connects the upper reservoir 2 and the underground cave 1.

[0045] The pumped storage unit 4 is arranged in the middle of the water delivery pipeline 3, and the pumped storage unit 4 can provide power for the water flow in the water delivery pipeline 3 and also convert the potential energy of the water flow in the water delivery pipeline 3 into electric energy; the pumped storage unit 4 includes a water pump turbine 41, the water pump turbine 41 is connected with a generator 42 and an electric motor 43, the water pump turbine 41 can provide power for the generator 42 to supply power to the external power grid, the electric motor 43 can supply power to the water pump turbine 41 through the external power grid, and the two ends of the water pump turbine 41 are connected with the water inlet pipeline 31 and the tail water pipeline 32 respectively.

[0046] The water delivery pipeline 3 includes a water inlet pipeline 31 and a tail water pipeline 32, the two ends of the water inlet pipeline 31 are connected with the upper reservoir 2 and the pumped storage unit 4 respectively, the two ends of the tail water pipeline 32 are connected with the pumped storage unit 4 and the underground cave 1 respectively, the water delivery pipeline 3 is usually selected from a steel pipe or a concrete pipe, and the material selection needs to consider the pressure resistance, corrosion resistance and durability, and the pipeline length and bending should be reduced as much as possible during arrangement, so as to reduce the hydraulic loss, the water inlet pipeline 31 and the tail water pipeline 32 are both provided with an opening and closing gate 33, the water inlet pipeline 31 has a certain slope to ensure that the water can flow smoothly, and an excessive slope will cause energy loss, and the slope change of the water inlet pipeline 31 reduces the impact on the water outlet

[0047] The air compression system 5 can compress the air in the underground cave 1 and fill the external air into the underground cave 1, the air compression system 5 includes a compressor 51 and an air pipeline 52, the compressor 51 is arranged on the ground, one end of the air pipeline 52 is connected to the output end of the compressor 51, the other end of the air pipeline 52 is connected to the inner cavity of the underground cave 1, the air pipeline 52 is provided with an air valve 53 close to one side of the underground cave 1, and the air pipeline 52 is provided with a pressure relief valve 54 away from the underground cave 1, the pressure relief valve 54 is connected with the compressor 51 in parallel, and the pressure relief valve 54 can release the gas in the underground cave 1.

[0048] The spraying system 6 is arranged on the top of the underground cave 1 and is used for enhancing the heat transfer between the high-pressure gas and the water in the tank to realize isothermal compression / expansion.

[0049] Embodiment 5 of the utility model: a kind of comprehensive energy storage system based on underground cave, it include: underground cave 1, underground cave 1 can be used as sealed storage medium, such as artificial chamber, abandoned mine, etc., can be artificially sealed.

[0050] The upper reservoir 2 is located on the ground and is higher than the underground cave 1 in horizontal position, and can be excavated into a reservoir or used as an above-ground water tank, and the upper reservoir 2 is communicated with the underground cave 1 by the water delivery pipeline 3, so that the upper reservoir 2 is communicated with the underground cave 1.

[0051] The pumped storage unit 4 is arranged in the middle of the water delivery pipeline 3, and can provide power for the water flow in the water delivery pipeline 3 and convert the potential energy of the water flow in the water delivery pipeline 3 into electric energy; the pumped storage unit 4 includes a water pump turbine 41, the water pump turbine 41 is connected with a generator 42 and an electric motor 43, the water pump turbine 41 can provide power for the generator 42 to supply power to the external power grid, the electric motor 43 can be powered by the external power grid to provide power for the water pump turbine 41, and the two ends of the water pump turbine 41 are connected with the water inlet pipeline 31 and the tail water pipeline 32 respectively.

[0052] The water delivery pipeline 3 includes a water inlet pipeline 31 and a tail water pipeline 32, the two ends of the water inlet pipeline 31 are connected with the upper reservoir 2 and the pumped storage unit 4 respectively, the two ends of the tail water pipeline 32 are connected with the pumped storage unit 4 and the underground cave 1 respectively, the water delivery pipeline 3 is usually selected from a steel pipe or a concrete pipe, and the material selection needs to consider the pressure resistance, corrosion resistance and durability, and the pipeline length and bending should be reduced as much as possible during arrangement, so that the hydraulic loss is reduced, the water inlet pipeline 31 and the tail water pipeline 32 are provided with opening and closing gates 33, the water inlet pipeline 31 has a certain slope to ensure that the water can flow smoothly, and an excessive slope will cause energy loss, and the slope change of the water inlet pipeline 31 reduces the impact on the water outlet

[0053] The air compression system 5 can compress the air in the underground cave 1 and fill the external air into the underground cave 1, the air compression system 5 includes a compressor 51 and an air pipeline 52, the compressor 51 is arranged on the ground, one end of the air pipeline 52 is connected with the output end of the compressor 51, the other end of the air pipeline 52 is connected to the inner cavity of the underground cave 1, the air pipeline 52 is provided with an air valve 53 close to one side of the underground cave 1, and the air pipeline 52 is provided with a pressure relief valve 54 away from the underground cave 1, the pressure relief valve 54 is connected with the compressor 51 in parallel, and the pressure relief valve 54 can release the gas in the underground cave 1.

[0054] The spraying system 6 is arranged on the top of the underground cave 1 and is used for enhancing the heat transfer between the high-pressure gas and the water in the tank to realize isothermal compression / expansion, the spraying system 6 includes a spraying pipeline 61 and a spraying device 62, one end of the spraying pipeline 61 is connected with the water delivery pipeline 3, the other end of the spraying pipeline 61 extends to the inner cavity of the underground cave 1 and is connected with the spraying device 62, and the spraying device 62 is arranged on the top of the inner cavity of the underground cave 1, the spraying pipeline 61 is provided with a spraying valve 63 and a check valve 64, and the check valve 64 prevents the gas from entering the spraying pipeline 61.

[0055] Specifically, the wind turbine generator set 7 and the photovoltaic generator set 8 are arranged on the ground, and the wind turbine generator set 7 and the photovoltaic generator set 8 are connected with the water pump water turbine 41.

[0056] The working principle of one embodiment of the utility model: the utility model takes the underground cave 1 as the water and gas co-containment energy storage tank, in the use process:

[0057] The initial state, the opening and closing gate 33 is opened, the water of the upper reservoir 2 enters the underground cave 1 through the self potential, the compressor 51 and the air valve 53 are opened simultaneously, the air in the underground cave 1 is compressed, until the system set gas initial pressure is reached, the opening and closing gate 33 is closed, the system enters the working state, and the compressor 51 does not work.

[0058] In the energy storage (charging) phase, the motor 43 drives the water pump part of the water pump turbine 41 to send water in the underground cave 1 to the upper reservoir 2, and the high-pressure air in the underground cave 1 expands to work, and the average kinetic energy of the gas molecules is converted into the potential energy of the water, wherein the electric energy of the motor 43 can be generated by the wind turbine generator set 7 and the photovoltaic generator set 8 around the reservoir.

[0059] In the energy release (discharging) phase, the water in the upper reservoir 2 passes through the water conduit 31 to drive the water turbine generator of the water pump turbine 41 to generate electricity by using the potential energy of the water, and the water enters the underground cave 1 to compress the air.

[0060] Among them, the spraying system 6 is used to enhance the heat transfer between the high-pressure gas and the water in the underground cave 1 to realize isothermal compression / expansion, and the compressor 51 only compresses the air to the initial pressure in the initial state, and the charging and discharging working state is not started; in order to realize the optimization of system conversion efficiency and investment cost, the initial water-gas ratio of the underground cave 1, the initial pressure of the gas, and the storage pressure can be adjusted and controlled to realize.

Claims

1. An integrated energy storage system based on an underground cavern, characterized in that, The utility model relates to an underground cavern (1); An upper reservoir (2) is located on the ground, and a water conveying pipeline (3) is connected between the underground cavern (1) and the upper reservoir (2); A pumped storage unit (4) is arranged in the middle of the water conveying pipeline (3), and the pumped storage unit (4) can provide power for water flow in the water conveying pipeline (3) and can also convert potential energy of water flow in the water conveying pipeline (3) into electric energy; An air compression system (5) can compress air in the underground cavern (1); A spraying system (6) is arranged on the top of the underground cavern (1). The water conveying pipeline (3) comprises a water inlet pipeline (31) and a tail water pipeline (32), two ends of the water inlet pipeline (31) are connected with the upper reservoir (2) and the pumped storage unit (4) respectively, and two ends of the tail water pipeline (32) are connected with the pumped storage unit (4) and the underground cavern (1) respectively.

2. An integrated energy storage system based on an underground cavern according to claim 1, characterized in that, The water inlet pipeline (31) and the tail water pipeline (32) are both provided with an open-close gate (33).

3. An integrated energy storage system based on an underground cavern according to claim 2, characterized in that, The pumped storage unit (4) comprises a water pump water turbine (41), the water pump water turbine (41) is connected with a generator (42) and an electric motor (43), the water pump water turbine (41) can provide power for the generator (42) to supply power to an external power grid, the electric motor (43) can supply power to the water pump water turbine (41) through the external power grid, and two ends of the water pump water turbine (41) are connected with the water inlet pipeline (31) and the tail water pipeline (32) respectively.

4. An integrated energy storage system based on an underground cavern according to claim 3, characterized in that, The utility model further comprises a wind turbine generator set (7) and a photovoltaic generator set (8) arranged on the ground, and the wind turbine generator set (7) and the photovoltaic generator set (8) are connected with the water pump water turbine (41).

5. An integrated energy storage system based on an underground cavern according to claim 4, characterized in that, The air compression system (5) comprises a compressor (51) and an air pipeline (52), the compressor (51) is arranged on the ground, one end of the air pipeline (52) connected with the output end of the compressor (51), and the other end of the air pipeline (52) is connected to the inner cavity of the underground cavern (1).

6. An integrated energy storage system based on underground caverns according to claim 1 or 5, characterized in that, An air valve (53) is arranged on the side of the air pipeline (52) close to the underground cavern (1), a pressure relief valve (54) is arranged on the end of the air pipeline (52) away from the underground cavern (1), and the pressure relief valve (54) is connected in parallel with the compressor (51).

7. An integrated energy storage system based on an underground cavern according to claim 6, characterized in that, The spraying system (6) comprises a spraying pipeline (61) and a spraying device (62), one end of the spraying pipeline (61) is connected with the water conveying pipeline (3), the other end of the spraying pipeline (61) extends to the inner cavity of the underground cavern (1) and is connected with the spraying device (62), and the spraying device (62) is arranged on the top of the inner cavity of the underground cavern (1).

8. An integrated energy storage system based on underground caverns according to claim 1 or 7, characterized in that, The spraying pipeline (61) is provided with a spraying valve (63) and a check valve (64).

9. An integrated energy storage system based on an underground cavern according to claim 8, characterized in that, ​

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