High-pressure air energy storage heat recovery device and control method thereof

Abstract

The invention discloses a high-pressure air energy storage heat recovery device and a control method thereof, and relates to the technical field of high-pressure gas energy storage heat recovery, and the high-pressure air energy storage heat recovery device comprises a liquid energy storage compressed gas system, a compression energy storage system and a user heat exchange system. The liquid energy storage compressed gas system comprises a high-pressure water tank, a power generation turbine, a high-pressure water pump, a water storage tank and high-pressure water tank heat exchange fins. The compression energy storage system comprises a temperature storage box, a compressor, a four-way reversing valve, a check valve, an expansion valve, a dryer and a liquid sight glass; the user heat exchange system comprises a heat storage box compressor heat exchanger and a heat storage box user heat exchanger. Energy waste in compression and expansion processes during gas energy storage is recycled, supplement is performed during power generation, so that the power storage efficiency is improved, meanwhile, cold and heat sources are provided for users through the cold and hot ends of the heat storage box, greenhouse gas emission can be reduced, and the device is more environmentally friendly and has good application prospects. And the requirements of modern society on efficient, reliable and environment-friendly energy solutions can be met.

Description

Technical Field

[0001] The present invention relates to the technical field of high-pressure gas energy storage heat recovery, and in particular to a high-pressure air energy storage heat recovery device and a control method thereof. Background Art

[0002] With the continuous growth of global energy demand and the improvement of environmental protection awareness, the development and utilization of renewable energy has become the main trend of global energy development. However, renewable energy such as wind power and solar energy are intermittent and unstable, which brings challenges to the stable operation of the power grid. Therefore, it is particularly important to develop efficient energy storage technology to balance supply and demand and improve the stability and reliability of the power grid.

[0003] High-pressure air energy storage technology is a technology that uses the air compression and expansion process to store and release energy. It converts electrical energy into the potential energy of high-pressure air when electricity is sufficient and stores it. When electricity demand peaks, high-pressure air is released to drive turbines to generate electricity, thereby achieving effective storage and utilization of energy. This technology has the advantages of high energy storage density, long life, and environmental friendliness, and is one of the effective means to solve the volatility of renewable energy.

[0004] However, in the high-pressure air energy storage system, the air compression process will generate a large amount of heat energy. If this part of heat energy is not recovered and utilized, it will cause energy waste. Therefore, developing a heat recovery device and its control method, which can effectively recover and utilize this part of heat energy, is of great significance to improving the energy efficiency and economy of the entire energy storage system. Summary of the invention

[0005] The present invention provides a heat recovery device for high-pressure air energy storage and a control method thereof, which solves the problem of waste of cold and heat sources in existing high-pressure gas energy storage.

[0006] To achieve the above-mentioned object, the present invention provides the following technical solutions: a heat recovery device for high-pressure air energy storage, comprising a liquid energy storage compressed gas system, a compressed energy storage system and a user heat exchange system;

[0007] The liquid energy storage compressed gas system comprises a high-pressure water tank, a power generation turbine, a high-pressure water pump, a water storage tank and a high-pressure water tank heat exchange fin; the high-pressure water tank contains high-pressure gas, and the high-pressure water tank heat exchange fin is located at the top of the gas inside the high-pressure water tank, and the two sides of the high-pressure water tank are respectively provided with a liquid inlet and a liquid outlet, and the liquid inlet is connected to the high-pressure water pump on one side, and the high-pressure water pump is connected to the water storage tank on one side, and the liquid outlet is connected to the power generation turbine on the other side, and the power generation turbine is connected to the other side of the water storage tank;

[0008] The compressed energy storage system includes a temperature storage box, a compressor and a four-way reversing valve; the user heat exchange system includes a temperature storage box compressor heat exchanger and a temperature storage box user heat exchanger; the temperature storage box compressor heat exchanger is located inside the temperature storage box, and the temperature storage box and the user are connected through the temperature storage box user heat exchanger;

[0009] One end of the temperature storage box compressor heat exchanger is connected to the compressor through an interface of a four-way reversing valve, the compressor is connected to one end of the high-pressure water tank heat exchange fin through another interface of the four-way reversing valve, and the other end of the temperature storage box compressor heat exchanger is connected to the other end of the high-pressure water tank heat exchange fin; the energy wasted in the compression and expansion process during gas energy storage is recovered and supplemented during power generation to improve the power storage efficiency, and at the same time, provide users with cold and heat sources through the cold and hot ends of the temperature storage box.

[0010] Preferably, a phase change material is provided inside the heat storage box for phase change energy storage, and heat exchange is then performed through the heat storage box.

[0011] Preferably, the compression energy storage system also includes a first check valve, a first expansion valve, a second check valve, a second expansion valve, a dryer and a sight glass, and the first check valve, the dryer, the sight glass and the second check valve are connected in sequence between the other end of the storage tank compressor heat exchanger and the high-pressure water tank heat exchange fins, and the first expansion valve and the second expansion valve are respectively connected in parallel to the first check valve and the second check valve.

[0012] Preferably, during energy storage, the gas heat in the high-pressure water tank is stored by the compression energy storage system, and the compressed gas is cooled.

[0013] Preferably, during discharge, the gas in the high-pressure water tank absorbs heat and is stored and heated and replenished through the compressed energy storage system.

[0014] The present invention also provides a control method for a heat recovery device of a high-pressure air energy storage, comprising the following steps:

[0015] 1) During energy storage, the high-pressure water pump pumps the liquid in the water storage tank into the high-pressure water tank. The liquid level in the high-pressure water tank rises and compresses the gas into high-pressure gas for energy storage. The gas is compressed to generate heat;

[0016] Then, the heat storage work is performed through the compression energy storage system. The compressor presses the high-pressure and high-temperature steam working medium into the four-way reversing valve. The four-way reversing valves ① and ②, ④ and ③ are turned on, and the hot working medium enters the temperature storage box for heat exchange. The temperature storage box is provided with a phase change material phase change energy storage, and then the heat is exchanged through the temperature storage box. The working medium releases part of the energy and condenses into a high-pressure and slightly cold liquid working medium. The high-pressure and slightly cold liquid working medium enters and passes through the first check valve. The first expansion valve is closed and does not work. Then it passes through the dryer and the sight glass, is blocked by the second check valve, and enters the second expansion valve to release pressure and expand. The working medium expands in volume, reduces pressure, and reduces temperature to become a low-pressure and low-temperature gas-liquid mixed working medium. The low-pressure and low-temperature gas-liquid mixed working medium enters the heat exchange fins of the high-pressure water tank, exchanges heat and cools the liquid energy storage compression gas system. The working medium boils and evaporates and takes away the heat energy. After the heat exchange, the working medium passes through ④ and ③ of the four-way reversing valve and returns to the compressor for pressurization, forming a heat exchange cycle.

[0017] 2) During discharge, the high-pressure water pump stops working, the liquid outlet of the high-pressure water tank opens, and the high-pressure liquid enters the power turbine to generate electricity. The compressed gas in the high-pressure water tank expands to do work, and the gas expands to do work and absorbs heat;

[0018] Then, the energy storage system is compressed to release heat. The compressor presses the high-pressure and high-temperature steam working medium into the four-way reversing valve. The four-way reversing valves ① and ④, ② and ③ are turned on. The hot working medium enters the heat exchange fins of the high-pressure water tank for heat exchange to provide heat. After releasing part of the energy, the working medium condenses into a high-pressure and slightly cold liquid working medium. The high-pressure and slightly cold liquid working medium passes through the second check valve. The second expansion valve is closed and does not work. Then, it passes through the sight glass and the dryer and is blocked by the first check valve. It enters the first expansion valve to release pressure and expand. The working medium expands and the pressure decreases to become a gas-liquid mixed working medium with a lower temperature. The low-pressure and low-temperature gas-liquid mixed working medium enters the temperature storage box for heat exchange. The working medium boils and evaporates and absorbs heat from the phase change material of the temperature storage box. The working medium after absorbing heat returns to ② and ③ of the four-way reversing valve and returns to the compressor for pressurization, forming a heat exchange cycle.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] 1. The present invention can avoid the waste of cold and heat sources in high-pressure gas energy storage, reduce the energy waste in the compression and expansion process when recovering gas energy storage, and supplement heat during power generation to improve power storage efficiency, which helps to reduce greenhouse gas emissions, is more environmentally friendly, and can meet the needs of modern society for efficient, reliable and environmentally friendly energy solutions.

[0021] 2. The present invention can not only store and release energy, but also extract cold and heat sources from the system for users to use. Such cold and heat sources can be directly used for heat exchange to meet the heating and cooling needs of industry or residences, improve energy utilization efficiency, and promote the optimization of energy structure and the sustainable development of energy systems.

[0022] 3. The present invention uses heat pump technology, and the system can convert low-grade thermal energy into high-grade thermal energy, thereby improving the working efficiency of the heat pump, which not only reduces energy consumption but also improves the economy of energy utilization.

[0023] 4. The present invention can adjust the working mode according to the specific needs of the user to adapt to energy storage needs of different scales, whether it is used for grid peak regulation, energy storage of renewable energy, or as a supply of cold and hot energy in industrial processes. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The accompanying drawings are used to provide further understanding of the present invention and constitute a part of the specification. They are used to explain the present invention together with the embodiments of the present invention and do not constitute a limitation of the present invention.

[0025] In the attached picture:

[0026] Figure 1 It is a structural schematic diagram of a heat recovery device for high-pressure air energy storage of the present invention;

[0027] Numbers in the figure: 1. Liquid energy storage compressed gas system; 2. High-pressure water tank; 3. Power generation turbine; 4. High-pressure water pump; 5. Water storage tank; 6. High-pressure water tank heat exchange fins; 7. Compressed energy storage system; 8. Temperature storage box; 9. Temperature storage box compressor heat exchanger; 10. Temperature storage box user heat exchanger; 11. Compressor; 12. Four-way reversing valve; 13. First check valve; 14. First expansion valve; 15. Second check valve; 16. Second expansion valve; 17. Dryer; 18. Sight glass; 19. User heat exchange system; 20. Liquid inlet; 21. Liquid outlet. DETAILED DESCRIPTION

[0028] The preferred embodiments of the present invention are described below in conjunction with the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0029] Example: Figure 1 As shown, a heat recovery device for high-pressure air energy storage includes a liquid energy storage compressed gas system 1, a compressed energy storage system 7 and a user heat exchange system 19;

[0030] The liquid energy storage compressed gas system 1 comprises a high-pressure water tank 2, a power generation turbine 3, a high-pressure water pump 4, a water storage tank 5 and a high-pressure water tank heat exchange fin 6; the high-pressure water tank 2 contains high-pressure gas, and the high-pressure water tank heat exchange fin 6 is located at the top of the gas inside the high-pressure water tank 2, and the two sides of the high-pressure water tank 2 are respectively provided with a liquid inlet 20 and a liquid outlet 21, and the high-pressure water pump 4 on one side is connected through the liquid inlet 20, and the high-pressure water pump 4 is connected to the water storage tank 5 on one side, and the power generation turbine 3 on the other side is connected through the liquid outlet 21, and the power generation turbine 3 is connected to the other side of the water storage tank 5;

[0031] The compression energy storage system 7 includes a temperature storage box 8, a compressor 11 and a four-way reversing valve 12; the user heat exchange system 19 includes a temperature storage box compressor heat exchanger 9 and a temperature storage box user heat exchanger 10; the temperature storage box compressor heat exchanger 9 is located inside the temperature storage box 8, and the temperature storage box 8 is connected to the user through the temperature storage box user heat exchanger 10, and the compression energy storage system 7 also includes a first check valve 13, a first expansion valve 14, a second check valve 15, a second expansion valve 16, a dryer 17 and a sight glass 18, the first check valve 13, the dryer 17, the sight glass 18 and the second check valve 15 are sequentially connected between the other end of the temperature storage box compressor heat exchanger 9 and the high-pressure water tank heat exchange fin 6, and the first expansion valve 14 and the second expansion valve 16 are respectively connected in parallel to the first check valve 13 and the second check valve 15;

[0032] One end of the temperature storage box compressor heat exchanger 9 is connected to the compressor 11 through an interface of a four-way reversing valve 12, the compressor 11 is connected to one end of the high-pressure water tank heat exchange fin 6 through another interface of the four-way reversing valve 12, and the other end of the temperature storage box compressor heat exchanger 9 is connected to the other end of the high-pressure water tank heat exchange fin 6; the energy wasted in the compression and expansion process during gas energy storage is recovered and supplemented during power generation to improve the power storage efficiency, and at the same time, the cold and hot ends of the temperature storage box 8 are used to provide cold and heat sources for the user 10.

[0033] During energy storage, the heat of the gas in the high-pressure water tank 2 is stored by the compression energy storage system 7 and the compressed gas is cooled; during discharge, the gas in the high-pressure water tank 2 absorbs heat and is stored by the compression energy storage system 7 for heating and replenishment.

[0034] The present invention also provides a control method for a heat recovery device of a high-pressure air energy storage, comprising the following steps:

[0035] 1. Energy storage stage:

[0036] 1) The high-pressure water pump 4 starts to pump the liquid in the water storage tank 5 into the high-pressure water tank 2. As the liquid level rises, the gas in the high-pressure water tank 2 is compressed to form high-pressure gas. During this energy storage process, the gas generates heat due to compression. This part of the heat needs to be effectively utilized or discharged to prevent the system from overheating and overpressure, which makes it more difficult to compress;

[0037] 2) Then, the heat storage work is started through the compression energy storage system 7, and the compressor 11 presses the high-pressure and high-temperature steam working medium into the four-way reversing valve 12. The ① and ②, ④ and ③ of the four-way reversing valve 12 are turned on, so that the hot working medium enters the temperature storage box 8 for heat exchange;

[0038] 3) In the heat storage box 8, the high-pressure and high-temperature steam working medium releases heat and condenses itself into a high-pressure and slightly colder liquid working medium; the high-pressure and slightly colder liquid working medium passes through the first check valve 13, and because the first expansion valve 14 does not work, the working medium continues to flow, and then passes through the dryer 17 and the sight glass 18, and is blocked by the second check valve 15;

[0039] 4) The working fluid enters the second expansion valve 16, and after pressure release and expansion, the working fluid volume expands, the pressure decreases, and the temperature decreases to become a low-pressure and low-temperature gas-liquid mixed working fluid. The low-pressure and low-temperature gas-liquid mixed working fluid enters the high-pressure water tank heat exchange fins 6, and the working fluid boils and evaporates, taking away heat energy to heat and cool the liquid energy storage compressed gas system 1;

[0040] 5) The working fluid after heat exchange passes through ④ and ③ of the four-way reversing valve 12 and returns to the compressor 11 for pressurization, forming a heat exchange cycle.

[0041] 2. Discharge stage:

[0042] 1) The high-pressure water pump 4 stops working, the liquid outlet 21 of the high-pressure water tank 2 opens, and the high-pressure liquid enters the power turbine 3 to generate electricity. At the same time, the compressed gas in the high-pressure water tank 2 begins to expand and do work. During this process, the gas expansion absorbs the surrounding heat, and the supplementary heat can maintain the gas pressure to discharge stably;

[0043] 2) Then, the compression energy storage system 7 is used to perform supplementary heat release, and the compressor 11 presses the high-pressure and high-temperature steam working medium into the four-way reversing valve 12. At this time, ① and ④, ② and ③ of the four-way reversing valve 12 are connected, so that the hot working medium can enter the high-pressure water tank heat exchange fins 6 for heat exchange;

[0044] 3) In the high-pressure water tank 2, the working medium releases part of its energy and condenses into a high-pressure and slightly cold liquid working medium. This working medium enters the second check valve 15. Since the second expansion valve 16 does not work, the working medium continues to flow, then passes through the sight glass 18 and the dryer 17, and is blocked by the first check valve 13;

[0045] 4) The working fluid enters the first expansion valve 14, and after pressure release and expansion, the working fluid volume expands, the pressure decreases, and the temperature decreases to become a low-pressure and low-temperature gas-liquid mixed working fluid. The low-pressure and low-temperature gas-liquid mixed working fluid enters the temperature storage tank 8 to evaporate and absorb heat;

[0046] 5) The working fluid after absorbing heat returns to ② and ③ of the four-way reversing valve 12, and returns to the compressor 11 for pressurization, forming a heat exchange cycle.

[0047] During the entire energy storage and discharge process, the various components of the system, including the high-pressure water pump 4, compressor 11, four-way reversing valve 12, check valve, expansion valve, dryer 17, sight glass 18, heat exchange fins and temperature storage box 8, all play a key role to ensure efficient conversion and storage of energy.

[0048] Finally, it should be noted that the above description is only a preferred example of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A heat recovery device for high-pressure air energy storage, Features: Including liquid energy storage compressed gas system, compressed energy storage system and user heat exchange system; The liquid energy storage compressed gas system comprises a high-pressure water tank, a power generation turbine, a high-pressure water pump, a water storage tank and a high-pressure water tank heat exchange fin; the high-pressure water tank contains high-pressure gas, and the high-pressure water tank heat exchange fin is located at the top of the gas inside the high-pressure water tank, and the two sides of the high-pressure water tank are respectively provided with a liquid inlet and a liquid outlet, and the liquid inlet is connected to the high-pressure water pump on one side, and the high-pressure water pump is connected to the water storage tank on one side, and the liquid outlet is connected to the power generation turbine on the other side, and the power generation turbine is connected to the other side of the water storage tank; The compressed energy storage system includes a temperature storage box, a compressor and a four-way reversing valve; the user heat exchange system includes a temperature storage box compressor heat exchanger and a temperature storage box user heat exchanger; the temperature storage box compressor heat exchanger is located inside the temperature storage box, and the temperature storage box and the user are connected through the temperature storage box user heat exchanger; One end of the temperature storage box compressor heat exchanger is connected to the compressor through an interface of a four-way reversing valve, the compressor is connected to one end of the high-pressure water tank heat exchange fin through another interface of the four-way reversing valve, and the other end of the temperature storage box compressor heat exchanger is connected to the other end of the high-pressure water tank heat exchange fin; the energy wasted in the compression and expansion process during gas energy storage is recovered and supplemented during power generation to improve the power storage efficiency, and at the same time, provide users with cold and heat sources through the cold and hot ends of the temperature storage box.

2. A heat recovery device for high-pressure air energy storage according to claim 1, Features: The heat storage box is provided with a phase change material for phase change energy storage, and heat is then exchanged through the heat storage box.

3. A heat recovery device for high-pressure air energy storage according to claim 1, Features: The compressed energy storage system also includes a first check valve, a first expansion valve, a second check valve, a second expansion valve, a dryer and a sight glass. The first check valve, the dryer, the sight glass and the second check valve are connected in sequence between the other end of the storage tank compressor heat exchanger and the high-pressure water tank heat exchange fins, and the first expansion valve and the second expansion valve are respectively connected in parallel to the first check valve and the second check valve.

4. A heat recovery device for high-pressure air energy storage according to claim 1, Features: During energy storage, the gas heat in the high-pressure water tank is stored by the compressed energy storage system, and the compressed gas is cooled.

5. A heat recovery device for high-pressure air energy storage according to claim 1, Features: During discharge, the gas in the high-pressure water tank absorbs heat and is stored and heated and replenished through the compressed energy storage system.

6. A control method for a heat recovery device of high-pressure air energy storage according to any one of claims 1 to 5, It is characterized in that The following steps are involved: 1) During energy storage, the high-pressure water pump pumps the liquid in the water storage tank into the high-pressure water tank. The liquid level in the high-pressure water tank rises and compresses the gas into high-pressure gas for energy storage. The gas is compressed to generate heat; Then, the compression energy storage system is used to perform heat storage work. The compressor presses the high-pressure and high-temperature steam working medium into the four-way reversing valve. The four-way reversing valves ① and ②, ④ and ③ are turned on. The hot working medium enters the temperature storage box for heat exchange and provides heat. After releasing part of the energy, the working medium condenses into a high-pressure and slightly cold liquid working medium. The high-pressure and slightly cold liquid working medium passes through the first check valve. The first expansion valve is closed and does not work. Then, it passes through the dryer and the sight glass, is blocked by the second check valve, and enters the second expansion valve to release pressure and expand. The working medium expands in volume, reduces pressure, and reduces temperature to become a low-pressure and low-temperature gas-liquid mixed working medium. The low-pressure and low-temperature gas-liquid mixed working medium enters the heat exchange fins of the high-pressure water tank, exchanges heat and cools the liquid energy storage compressed gas system. The working medium boils and evaporates to take away heat energy. The working medium after heat exchange passes through ④ and ③ of the four-way reversing valve and returns to the compressor for pressurization, forming a heat exchange cycle. 2) During discharge, the high-pressure water pump stops working, the liquid outlet of the high-pressure water tank opens, the high-pressure liquid enters the power turbine to generate electricity, and then flows back to the water tank. The compressed gas in the high-pressure water tank expands to do work, and the gas expansion does work and absorbs heat; Then, the energy storage system is compressed to supplement the heat release work. The compressor presses the high-pressure and high-temperature steam working medium into the four-way reversing valve. The four-way reversing valves ① and ④, ② and ③ are turned on, and the hot working medium enters the heat exchange fins of the high-pressure water tank for heat exchange to provide heat. After releasing part of the energy, the working medium condenses into a high-pressure and slightly cold liquid working medium. The high-pressure and slightly cold liquid working medium passes through the second check valve, and the second expansion valve is closed and does not work. Then, it passes through the sight glass and the dryer, is blocked by the first check valve, and enters the first expansion valve to release pressure and expand. The working medium expands in volume, reduces pressure, and reduces temperature to become a low-pressure and low-temperature gas-liquid mixed working medium. The low-pressure and low-temperature gas-liquid mixed working medium enters the temperature storage box for heat exchange, and the working medium boils and evaporates to absorb heat from the phase change material of the temperature storage box. After absorbing heat, the working medium returns to ② and ③ of the four-way reversing valve and returns to the compressor for pressurization, forming a heat exchange cycle.

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