A multi-energy cogeneration energy storage system coupled with compressed air and water and method thereof

Abstract

The present invention belongs to the field of energy storage technology and relates to a multi-energy cogeneration energy storage system coupled with compressed air and water and a method thereof, comprising an air compressor, a first heat exchanger, a second heat exchanger, an air turbine, and a cooling module; a first circulation loop, wherein the circulating medium is molten salt; and a second circulation loop, wherein the circulating medium is water, comprising a low-temperature water tank, a first booster pump, a second heat exchanger, a high-temperature water tank, a flash tank, a third heat exchanger, a turbine high-pressure cylinder, and a heating module, which are connected end to end. The present invention can store the compression heat generated by the compressed air in the molten salt and water, avoiding the special geographical conditions required for storing high-pressure air. At the same time, during the energy release phase, the stored water is flashed and heated by the molten salt before entering the steam Rankine cycle to perform work. Furthermore, the system can achieve combined heat and power generation in winter and combined cooling and power generation in summer, thereby realizing the combined supply of different types of energy in different seasons and improving energy supply efficiency.

Description

Technical Field

[0001] The present invention belongs to the technical field of energy storage, and relates to a multi-energy cogeneration energy storage system coupled with compressed air and water and a method thereof. Background Art

[0002] With the large-scale integration of renewable energy and the rapid development of smart grids, energy storage technology has become a key enabler for improving the regulation capabilities of power systems and ensuring stable grid operation. As a key hub in the energy internet, energy storage systems play an irreplaceable role in achieving peak load shifting and facilitating the absorption of new energy sources.

[0003] Existing energy storage technologies often utilize pumped hydro and compressed air storage, which offer advantages such as large capacity and long lifespan. However, these technologies also have drawbacks to varying degrees. First, their construction is limited by specific geographical conditions, making them difficult to deploy on a large scale. Second, existing energy storage systems generally employ a single energy output mode, focusing solely on the storage and release of electrical energy, resulting in low energy supply efficiency. Summary of the Invention

[0004] The purpose of the present invention is to provide a multi-energy cogeneration and energy storage system coupled with compressed air and water and a method thereof, which can reduce the demand for special geographical environments while supplying multiple energy sources and improving energy utilization efficiency.

[0005] To achieve the above objectives, the present invention provides the following technical solutions:

[0006] A multi-energy cogeneration and energy storage system coupled with compressed air and water includes an air compressor, a first heat exchanger, a second heat exchanger, and an air turbine connected in sequence. The air compressor is used to compress the introduced air. The air turbine is coaxially arranged with the air compressor. The power generated by the expansion work of the air turbine is used to drive the air compressor. At the same time, the cooling capacity generated by the expansion work is used to provide cooling to users through a cooling module. The system also includes:

[0007] The first circulation loop, in which the circulating medium is molten salt, comprises a low-temperature molten salt tank, a first heat exchanger, a high-temperature molten salt tank and a third heat exchanger connected end to end. The first heat exchanger is used to realize heat exchange between molten salt and air.

[0008] The second circulation loop, in which the circulating medium is water, includes a low-temperature water tank, a first booster pump, a second heat exchanger, a high-temperature water tank, a flash tank, a third heat exchanger and a steam turbine high-pressure cylinder, which are connected end to end in sequence; the first booster pump is used to pressurize the water, the second heat exchanger is used to realize heat exchange between water and air, the flash tank is used to flash evaporate the water stored in the high-temperature water tank to obtain steam, the third heat exchanger is used to realize heat exchange between molten salt and steam to increase the temperature of the steam, and the power generated by the expansion work of the steam turbine high-pressure cylinder is used to drive the generator to generate electricity, while the waste heat of the steam is used to provide heating to users through the heating module.

[0009] The present invention is also characterized in that:

[0010] The cooling module includes:

[0011] The refrigeration heat exchanger has a first inlet connected to the outlet of the air turbine, the first outlet of the refrigeration heat exchanger is connected to the atmosphere, and the second inlet and second outlet of the refrigeration heat exchanger are connected to a refrigeration circulation loop. The circulating medium in the refrigeration circulation loop enters the refrigeration heat exchanger for heat exchange and cooling, and then provides cooling to the user.

[0012] The heating module includes:

[0013] The heating heat exchanger has a first inlet connected to the first outlet of the turbine high-pressure cylinder, the first outlet of the heating heat exchanger is connected to the first inlet of the low-temperature water tank, and the second inlet and the second outlet of the heating heat exchanger are connected to a heating circulation loop. The circulating medium in the heating circulation loop enters the heating heat exchanger for heat exchange and then provides heating to the user.

[0014] The third inlet of the heating heat exchanger is connected to the flash tank via a first throttle valve.

[0015] The second outlet of the steam turbine high-pressure cylinder is connected to the inlet of the steam turbine low-pressure cylinder. The steam turbine low-pressure cylinder is used to utilize the steam expanded and worked by the steam turbine high-pressure cylinder to expand and work again to generate power to drive the generator to generate electricity. The outlet of the steam turbine low-pressure cylinder is connected to the second inlet of the low-temperature water tank. A condenser and a second booster pump are arranged between the steam turbine low-pressure cylinder and the low-temperature water tank. The inlet of the condenser is connected to the outlet of the steam turbine low-pressure cylinder, the outlet of the condenser is connected to the inlet of the second booster pump, and the outlet of the second booster pump is connected to the second inlet of the low-temperature water tank.

[0016] A reheater is arranged between the high-pressure cylinder of the turbine and the low-pressure cylinder of the turbine, the second outlet of the high-pressure cylinder of the turbine is connected to the first inlet of the reheater, the first outlet of the reheater is connected to the inlet of the low-pressure cylinder of the turbine, the second inlet of the reheater is connected to the flash tank, a medium-temperature water tank is arranged between the reheater and the first booster pump, the inlet of the medium-temperature water tank is connected to the second outlet of the reheater, and the outlet of the medium-temperature water tank is connected to the inlet of the first booster pump through a second throttle valve.

[0017] A cooler is arranged between the medium-temperature water tank and the second throttle valve, the first inlet of the cooler is connected to the outlet of the medium-temperature water tank, the first outlet of the medium-temperature water tank is connected to the second throttle valve, the inlet of the air compressor is connected to the first outlet of the preheater, the first inlet of the preheater is connected to the atmosphere, the second inlet of the preheater is connected to the second outlet of the cooler, the second outlet of the preheater is connected to the second inlet of the cooler, and the third inlet of the preheater is connected to the waste heat source.

[0018] A method for a multi-energy cogeneration and energy storage system coupled with compressed air and water, comprising the following steps:

[0019] Normal temperature and normal pressure air enters the preheater for preheating and becomes medium temperature and normal pressure air. The medium temperature and normal pressure air enters the air compressor for compression and becomes high temperature and high pressure air. The high temperature and high pressure air enters the first heat exchanger, the second heat exchanger and the air turbine in sequence. The low temperature molten salt enters the first heat exchanger for heat exchange and becomes high temperature molten salt, which is stored in the high temperature molten salt tank. The low temperature water is pressurized by the first booster pump and enters the second heat exchanger for heat exchange and becomes medium temperature and high pressure water, which is stored in the high temperature water tank, completing energy storage. After two heat exchanges, the high temperature and high pressure air expands and performs work in the air turbine and becomes low temperature and normal pressure air. At the same time, the power generated by the expansion work is transmitted to the air compressor.

[0020] Medium-temperature, high-pressure water enters the flash tank for flash evaporation, generating medium-temperature saturated steam and medium-temperature saturated water. The medium-temperature saturated steam enters the third heat exchanger for heat exchange with high-temperature molten salt to increase its temperature, and then enters the high-pressure cylinder of the steam turbine to expand and perform work, thereby driving the generator to generate electricity.

[0021] The steam that has expanded and worked in the high-pressure cylinder of the steam turbine enters the reheater, exchanges heat with the medium-temperature saturated water produced in the flash tank to increase its temperature, and then enters the low-pressure cylinder of the steam turbine to expand and work, driving the generator to generate electricity. At the same time, when providing cooling, the low-temperature, normal-pressure air that has expanded and worked in the air turbine enters the refrigeration heat exchanger to provide cooling to users.

[0022] During heating, the steam expanded and worked in the high-pressure cylinder of the steam turbine and the medium-temperature saturated water in the flash tank enter the heating heat exchanger to provide heating to the users.

[0023] The temperature of medium-temperature and normal-pressure air is 140℃~160℃ and the pressure is 101.3kPa; the temperature of high-temperature and high-pressure air is 300℃~350℃ and the pressure is 300kPa~400kPa; the temperature of low-temperature and normal-pressure air is -15℃~10℃ and the pressure is 101.3kPa; the temperature of low-temperature water is 25℃~30℃; the temperature of medium-temperature and high-pressure water is 210℃~250℃ and the pressure is 3.5MPa~4.0MPa; the temperature of low-temperature molten salt is 200℃~240℃; the temperature of high-temperature molten salt is 200℃~240℃; the temperature of high-temperature molten salt is 200℃~240℃. The temperature of salt is 290℃~340℃, the temperature of medium-temperature saturated steam is 190℃~210℃ and the pressure is 1.3MPa~1.9MPa, the temperature of medium-temperature saturated water is 190℃~210℃ and the pressure is 1.3MPa~1.9MPa, the temperature of high-temperature medium-pressure steam is 280℃~330℃ and the pressure is 1.3MPa~1.9MPa, the temperature of medium-temperature atmospheric pressure steam is 100℃~110℃ and the pressure is 101.3kPa, and the temperature of medium-temperature water is 190℃~210℃.

[0024] The multi-energy cogeneration and storage system and method of the present invention coupled with compressed air and water have the following advantages:

[0025] The present invention can store the compression heat generated by compressed air in molten salt and water through the cooperation of an air compressor, an air turbine, a first heat exchanger, a second heat exchanger, a first circulation loop, a second circulation loop, a cooling module and a heating module, thereby avoiding the special geographical conditions required for storing high-pressure air. At the same time, in the energy release stage, the stored water is flashed and heated with molten salt before entering the steam Rankine cycle to perform work, and can achieve cogeneration of heat and power in winter and cogeneration of cooling and power in summer. The turbine working mode is switched between back pressure and condensing according to the season, thereby achieving the combined supply of different types of energy in different seasons and improving the energy supply efficiency. At the same time, by coaxially arranging the air turbine and the air compressor, the power generated by the expansion work of the air turbine can be used to drive the air compressor, offsetting part of the power consumption of the air compressor and reducing energy consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic diagram of the overall structure of the present invention.

[0027] Figure 2 It is a schematic diagram of the overall process of the present invention.

[0028] Reference numerals:

[0029] 1. Preheater, 2. Air compressor, 3. First heat exchanger, 4. Second heat exchanger, 5. Air turbine, 6. Refrigeration heat exchanger, 7. Low temperature water tank, 8. First booster pump, 9. High temperature water tank, 10. Low temperature molten salt tank, 11. High temperature molten salt tank, 12. Flash tank, 13. Third heat exchanger, 14. Steam turbine high pressure cylinder, 15. Heating heat exchanger, 16. First throttle valve, 17. Reheater, 18. Steam turbine low pressure pressure cylinder, 19. condenser, 20. second boost pump, 21. medium-temperature water tank, 22. cooler, 23. second throttle valve, 101. first control valve, 102. second control valve, 103. third control valve, 104. fourth control valve, 105. fifth control valve, 106. sixth control valve, 107. seventh control valve, 108. eighth control valve, 109. ninth control valve, 110. tenth control valve. DETAILED DESCRIPTION

[0030] The technical solutions in the present invention will be described clearly and in detail below with reference to the accompanying drawings. In the description of the embodiments of the present invention, unless otherwise specified, " / " means or, for example, A / B can mean A or B: "and / or" in the text is only a description of the association relationship of associated objects, indicating that there can be three relationships, such as A and / or B, which can mean: A exists alone, A and B exist at the same time, and B exists alone. In addition, in the description of the embodiments of the present invention, "multiple" refers to two or more than two. The following terms "first" and "second" are used for descriptive purposes only and cannot be understood as implying or suggesting relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features.

[0031] like Figure 1As shown, the present invention provides a multi-energy cogeneration energy storage system coupled with compressed air and water, comprising an air compressor 2, an air turbine 5, a first heat exchanger 3, a second heat exchanger 4, a first circulation loop and a second circulation loop, the air compressor 2 is used to compress the introduced air, the air turbine 5 is coaxially arranged with the air compressor 2, and the power generated by its expansion work is used to drive the air compressor 2, while the cooling capacity generated by the expansion work is used to provide cooling to the user through the cooling module, the circulating medium of the first circulation loop is molten salt, the first circulation loop comprises a low-temperature molten salt tank 10, a first heat exchanger 3, a high-temperature molten salt tank 11 and a third heat exchanger 13 connected end to end in sequence, the first heat exchanger 3 is used to realize heat exchange between molten salt and air, the circulating medium of the second circulation loop is water, the second circulation loop comprises a low-temperature water tank 7, a first booster pump 8, a second heat exchanger 4, a high-temperature water tank 9, a flash tank 12, a third heat exchanger 13 and a turbine high-pressure cylinder 14 connected end to end in sequence, the first booster pump 8 is used to pressurize the water, and the second heat exchanger 4 is used to Heat exchange between water and air is achieved, so that the water coming out of the low-temperature water tank 7 becomes high-pressure water. The flash tank 12 is used to flash the water stored in the high-temperature water tank 9 to obtain steam. The third heat exchanger 13 is used to achieve heat exchange between molten salt and steam to increase the temperature of the steam. The power generated by the expansion work of the high-pressure cylinder 14 of the steam turbine is used to drive the generator to generate electricity. At the same time, the waste heat of the steam is used to provide heating to users through the heating module. The present invention can store the compression heat generated by the compressed air in molten salt and water through the cooperation of the air compressor 2, the air turbine 5, the first heat exchanger 3, the second heat exchanger 4, the first circulation loop and the second circulation loop, avoiding the special geographical conditions required for storing high-pressure air. At the same time, in the energy release stage, the stored water is flashed and heated by the molten salt before entering the steam Rankine cycle to perform work, and can achieve cogeneration of heat and power in winter and cogeneration of cooling and power in summer. The turbine working mode is switched between back pressure and condensing according to the season, thereby achieving the combined supply of different types of energy in different seasons and improving energy supply efficiency.

[0032] like Figure 1 As shown, the outlet of the low-temperature molten salt tank 10 is connected to the first inlet of the first heat exchanger 3, low-temperature molten salt is stored in the low-temperature molten salt tank 10, the inlet of the high-temperature molten salt tank 11 is connected to the first outlet of the first heat exchanger 3, low-temperature water is stored in the low-temperature water tank 7, the inlet of the first booster pump 8 is connected to the outlet of the low-temperature water tank 7, the outlet of the first booster pump 8 is connected to the first inlet of the second heat exchanger 4, the first booster pump 8 is used to pressurize the water, the inlet of the high-temperature water tank 9 is connected to the first outlet of the second heat exchanger 4, the inlet of the flash tank 12 is connected to the outlet of the high-temperature water tank 9, the first inlet of the third heat exchanger 13 is connected to the first outlet of the flash tank 12, the first outlet of the third heat exchanger 13 is connected to the steam power generation module, the second inlet of the third heat exchanger 13 is connected to the outlet of the high-temperature molten salt tank 11, and the second outlet of the third heat exchanger 13 is connected to the inlet of the low-temperature molten salt tank 10.

[0033] like Figure 1 As shown, the cooling module includes a refrigeration heat exchanger 6, a first inlet of the refrigeration heat exchanger 6 is connected to the outlet of the air turbine 5, a first outlet of the refrigeration heat exchanger 6 is connected to the atmosphere, and a second inlet and a second outlet of the refrigeration heat exchanger 6 are connected to a cooling circulation loop. The circulating medium in the cooling circulation loop enters the refrigeration heat exchanger 6 for heat exchange and cooling to provide cooling to the user.

[0034] like Figure 1 As shown, the heating module includes: a heating heat exchanger 15, the first inlet of the heating heat exchanger 15 is connected to the first outlet of the turbine high-pressure cylinder 14, the first outlet of the heating heat exchanger 15 is connected to the first inlet of the low-temperature water tank 7, the second inlet and the second outlet of the heating heat exchanger 15 are connected to a heating circulation loop, and the circulating medium in the heating circulation loop enters the heating heat exchanger 15 for heat exchange and temperature rise to provide heating to the user.

[0035] like Figure 1 As shown, the third inlet of the heating heat exchanger 15 is connected to the flash tank 12 via the first throttle valve 16 , that is, the second outlet of the flash tank 12 is connected to the inlet of the first throttle valve 16 , and the outlet of the first throttle valve 16 is connected to the third inlet of the heating heat exchanger 15 .

[0036] like Figure 1 As shown, the low-pressure cylinder 18 of the steam turbine is used to utilize the steam expanded and worked by the high-pressure cylinder 14 of the steam turbine to expand and work again to generate power to drive the generator to generate electricity. The outlet of the low-pressure cylinder 18 of the steam turbine is connected to the second inlet of the low-temperature water tank 7. A condenser 19 and a second booster pump 20 are provided between the low-pressure cylinder 18 of the steam turbine and the low-temperature water tank 7. The inlet of the condenser 19 is connected to the outlet of the low-pressure cylinder 18 of the steam turbine, and the outlet of the condenser 19 is connected to the inlet of the second booster pump 20. The outlet of the second booster pump 20 is connected to the second inlet of the low-temperature water tank 7.

[0037] like Figure 1 As shown, a reheater 17 is provided between the high-pressure cylinder 14 of the turbine and the low-pressure cylinder 18 of the turbine, the second outlet of the high-pressure cylinder 14 of the turbine is connected to the first inlet of the reheater 17, the first outlet of the reheater 17 is connected to the inlet of the low-pressure cylinder 18 of the turbine, the second inlet of the reheater 17 is connected to the flash tank 12, that is, the second inlet of the reheater 17 is connected to the third outlet of the flash tank 12, a medium-temperature water tank 21 is provided between the reheater 17 and the first booster pump 8, the inlet of the medium-temperature water tank 21 is connected to the second outlet of the reheater 17, and the outlet of the medium-temperature water tank 21 is connected to the inlet of the first booster pump 8 through a second throttle valve 23.

[0038] like Figure 1As shown, a cooler 22 is provided between the medium-temperature water tank 21 and the second throttle valve 23, a first inlet of the cooler 22 is connected to the outlet of the medium-temperature water tank 21, a first outlet of the medium-temperature water tank 21 is connected to the second throttle valve 23, an inlet of the air compressor 2 is connected to the first outlet of the preheater 1, the first inlet of the preheater 1 is connected to the atmosphere, a second inlet of the preheater 1 is connected to the second outlet of the cooler 22, a second outlet of the preheater 1 is connected to the second inlet of the cooler 22, and a third inlet of the preheater 1 is connected to a waste heat source.

[0039] Preferably, the waste heat source is the waste heat from a chemical plant or a thermal power plant as medium and low temperature waste heat. The medium and low temperature waste heat and the heat in the cooler 22 are introduced into the preheater 1 to heat the air, thereby increasing the inlet temperature of the air compressor 2 and improving the overall performance of the system.

[0040] like Figure 1 As shown, the inlet of the preheater 1 is provided with a first control valve 101, the outlet of the low-temperature water tank 7 is provided with a second control valve 102, the outlet of the low-temperature molten salt tank 10 is provided with a third control valve 103, the outlet of the high-temperature water tank 9 is provided with a fourth control valve 104, the outlet of the high-temperature molten salt tank 11 is provided with a fifth control valve 105, the first outlet of the turbine high-pressure cylinder 14 is provided with a sixth control valve 106, the second outlet of the flash tank 12 is provided with a seventh control valve 107, the second outlet of the turbine high-pressure cylinder 14 is provided with an eighth control valve 108, the third outlet of the flash tank 12 is provided with a ninth control valve 109, and the outlet of the medium-temperature water tank 21 is provided with a tenth control valve 110.

[0041] like Figure 1 As shown, the input shaft of the air compressor 2 is connected to a motor, which is convenient for utilizing the electric energy during low-peak hours to power the motor and drive the air compressor 2 to compress air and store energy. The input shaft of the air compressor 2 is connected to the output shaft of the air turbine 5, which is convenient for the air turbine 5 to drive the air compressor 2 to rotate and offset part of the power consumption of the air compressor 2.

[0042] like Figure 2 As shown, the present invention also provides a multi-energy cogeneration and energy storage system method coupled with compressed air and water, comprising the following steps:

[0043] Normal temperature and normal pressure air enters the preheater 1 for preheating and becomes medium temperature and normal pressure air. The medium temperature and normal pressure air enters the air compressor 2 for compression and becomes high temperature and high pressure air. The high temperature and high pressure air enters the first heat exchanger 3, the second heat exchanger 4 and the air turbine 5 in sequence. The low temperature molten salt enters the first heat exchanger 3 for heat exchange and becomes high temperature molten salt, which is stored in the high temperature molten salt tank 11. The low temperature water is pressurized by the first booster pump 8 and enters the second heat exchanger 4 for heat exchange and becomes medium temperature and high pressure water, which is stored in the high temperature water tank 9 to complete energy storage. After two heat exchanges, the high temperature and high pressure air expands and does work in the air turbine 5 and becomes low temperature and normal pressure air. At the same time, the power generated by the expansion work is transmitted to the air compressor 2.

[0044] Medium-temperature, high-pressure water enters the flash tank 12 for flash evaporation, generating medium-temperature saturated steam and medium-temperature saturated water. The medium-temperature saturated steam enters the third heat exchanger 13 for heat exchange with high-temperature molten salt to increase its temperature, and then enters the high-pressure cylinder 14 of the steam turbine to expand, perform work, and drive the generator to generate electricity.

[0045] The steam expanded and worked in the high-pressure cylinder 14 of the steam turbine enters the reheater 17, exchanges heat with the medium-temperature saturated water produced in the flash tank 12 to increase its temperature, and then enters the low-pressure cylinder 18 of the steam turbine to expand and work and drive the generator to generate electricity. At the same time, when providing cooling, the low-temperature, normal-pressure air expanded and worked by the air turbine 5 enters the refrigeration heat exchanger 6 to provide cooling to the user.

[0046] During heating, the steam expanded and worked in the high-pressure cylinder 14 of the steam turbine and the medium-temperature saturated water in the flash tank 12 enter the heating heat exchanger 15 to provide heating to the users.

[0047] Among them, the temperature of medium-temperature atmospheric pressure air is 140℃~160℃ and the pressure is 101.3kPa; the temperature of high-temperature and high-pressure air is 300℃~350℃ and the pressure is 300kPa~400kPa; the temperature of low-temperature atmospheric pressure air is -15℃~10℃ and the pressure is 101.3kPa; the temperature of low-temperature water is 25℃~30℃; the temperature of medium-temperature and high-pressure water is 210℃~250℃ and the pressure is 3.5MPa~4.0MPa; the temperature of low-temperature molten salt is 200℃~240℃; the temperature of high-temperature molten salt is 200℃~240℃; the temperature of high-temperature molten salt is 200℃~240℃. The temperature of molten salt is 290℃~340℃, the temperature of medium-temperature saturated steam is 190℃~210℃ and the pressure is 1.3MPa~1.9MPa, the temperature of medium-temperature saturated water is 190℃~210℃ and the pressure is 1.3MPa~1.9MPa, the temperature of high-temperature medium-pressure steam is 280℃~330℃ and the pressure is 1.3MPa~1.9MPa, the temperature of medium-temperature atmospheric pressure steam is 100℃~110℃ and the pressure is 101.3kPa, and the temperature of medium-temperature water is 190℃~210℃.

[0048] Working principle: In the initial state, all ten control valves are closed.

[0049] When storing energy in winter, the first control valve 101, the second control valve 102, and the third control valve 103 are opened, and the fourth control valve 104, the fifth control valve 105, the sixth control valve 106, the seventh control valve 107, the eighth control valve 108, the ninth control valve 109, and the tenth control valve 110 are closed. Normal temperature and normal pressure air enters the preheater 1 in sequence, exchanges heat with medium and low temperature waste heat (provided by waste heat from factories or thermal power plants) to medium temperature, and then enters the air compressor 2 for compression into high temperature and high pressure air. The high temperature and high pressure air enters the first exchanger in sequence. The low-temperature molten salt enters the first heat exchanger 3 and the second heat exchanger 4 and the air turbine 5 for heat exchange to become high-temperature molten salt, which is stored in the high-temperature molten salt tank 11. The low-temperature water is pressurized by the first booster pump 8 and enters the second heat exchanger 4 for heat exchange to become medium-temperature, high-pressure water, which is stored in the high-temperature water tank 9, completing winter energy storage. After two heat exchanges, the high-temperature and high-pressure air expands and does work in the air turbine 5 to become low-temperature, normal-pressure air. At the same time, the power generated by the expansion work is transmitted to the air compressor 2 to offset part of the power consumption of the air compressor 2.

[0050] When storing energy in summer, the first control valve 101, the second control valve 102, the third control valve 103, and the tenth control valve 110 are opened, and the fourth control valve 104, the fifth control valve 105, the sixth control valve 106, the seventh control valve 107, the eighth control valve 108, and the ninth control valve 109 are closed. The normal temperature and normal pressure air enters the preheater 1 and is heat-exchanged to medium temperature (the heat in the preheater 1 is provided by the medium temperature water stored in the medium temperature tank 21) and then enters the air compressor 2 for compression to become high temperature and high pressure air. The high temperature and high pressure air enters the first heat exchanger 3, the second heat exchanger 4, and the air turbine 5 in sequence. The low temperature molten salt enters the first heat exchanger 3 for heating. The low-temperature water is exchanged into high-temperature molten salt and stored in the high-temperature molten salt tank 11. The low-temperature water is pressurized by the first booster pump 8 and enters the second heat exchanger 4 for heat exchange to become medium-temperature, high-pressure water and stored in the high-temperature water tank 9 to complete energy storage. After two heat exchanges, the high-temperature and high-pressure air expands and does work in the air turbine 5 to become low-temperature, normal-pressure air. The second conveying component conveys the circulating working fluid into the refrigeration heat exchanger 6 for heat exchange with the low-temperature, normal-pressure air, and conveys the refrigerated circulating working fluid to the user for cooling. The low-temperature, normal-pressure air absorbs heat and is discharged into the atmosphere. At the same time, the power generated by the expansion work is conveyed to the air compressor 2 to offset part of the power consumption of the air compressor 2.

[0051] When the system releases energy in winter, the first control valve 101, the second control valve 102, the third control valve 103, the eighth control valve 108, the ninth control valve 109 and the tenth control valve 110 are closed, and the fourth control valve 104, the fifth control valve 105, the sixth control valve 106 and the seventh control valve 107 are opened. The medium-temperature, high-pressure water in the high-temperature water tank 9 enters the flash tank 12 for flash evaporation to produce medium-temperature saturated steam and saturated water. The medium-temperature, medium-pressure steam enters the third heat exchanger 13 and exchanges heat with the high-temperature molten salt flowing out of the high-temperature molten salt tank 11 to become high-temperature, medium-pressure steam. The medium-temperature saturated water produced by the flash tank is throttled by the first throttle valve and enters the heating heat exchanger 15 together with the medium-temperature normal-pressure steam after expansion in the high-pressure cylinder 14 of the turbine to exchange heat to low-temperature normal-pressure water, and then enters the low-temperature water tank 7 for storage. The first conveying component conveys the circulating working fluid into the heating heat exchanger 15 for heat exchange, and conveys the heated circulating working fluid to the user for heating. The high-temperature molten salt releases heat in the third heat exchanger 13 and then enters the low-temperature molten salt tank 10 for storage.

[0052] When the system releases energy in summer, the first control valve 101, the second control valve 102, the third control valve 103, the sixth control valve 106, the seventh control valve 107 and the tenth control valve 110 are closed, and the fourth control valve 104, the fifth control valve 105, the eighth control valve 108 and the ninth control valve 109 are opened. The medium-temperature, high-pressure water in the high-temperature water tank 9 enters the flash tank 12 for flash evaporation to produce medium-temperature saturated steam and saturated water. The medium-temperature, medium-pressure steam enters the third heat exchanger 13 and exchanges heat with the high-temperature molten salt flowing out of the high-temperature molten salt tank 11 to become high-temperature, medium-pressure steam, and then enters the high-pressure cylinder 14 of the steam turbine to expand and do work and drive the generator to generate electricity. The expanded steam enters the reheater 17 and exchanges heat with the medium-temperature, saturated water at the outlet of the flash tank 12 to increase the pressure. After heating, it enters the low-pressure steam turbine 18 to further expand and do work and drive the generator to generate electricity. Finally, the steam expanded to low pressure is condensed into saturated liquid through the condenser 19 and then enters the second water pump 20 to be pressurized to normal pressure and enters the low-temperature water tank 7 for storage. The high-temperature molten salt releases heat in the third heat exchanger 13 and then enters the low-temperature molten salt tank 10 for storage. The medium-temperature saturated water at the outlet of the flash tank 12 is converted into medium-temperature water after heat release in the reheater 17 and enters the medium-temperature water tank 21 for storage. The medium-temperature water stored in the medium-temperature water tank 21 releases heat and cools down in the cooler 22, and is used to heat the air in the preheater 1. It is then reduced in pressure by the second throttle valve 23 to form low-temperature water, which is mixed with the low-temperature water in the low-temperature water tank and enters the next cycle, thus completing the summer energy release process.

[0053] Other advantages of the multi-energy cogeneration and storage system coupled with compressed air and water and the method thereof of the present invention are as follows:

[0054] First, the present invention uses air and water as working fluids, which are cheap, readily available, clean and pollution-free. At the same time, the steam turbine, condenser, water pump, etc. can directly utilize existing equipment in thermal power plants, saving costs.

[0055] Second, the present invention sets a flash tank in the energy release stage, and uses medium-high-quality compression heat to generate medium-temperature and medium-pressure steam as the energy release working medium in a flash manner, avoiding the traditional steam Rankine cycle from generating working steam by absorbing a large amount of latent heat, thereby improving the system's energy conversion efficiency.

[0056] Third, the present invention does not require the storage of high-pressure air, which reduces the system footprint and improves layout flexibility.

[0057] Fourthly, the present invention adopts a two-stage heat exchanger to recover the heat of high-pressure air, and also adopts multiple heat exchangers to utilize the heat, thereby realizing the cascade utilization of energy and improving the energy utilization rate.

[0058] It will be understood that the present invention is described by way of some embodiments, and it will be appreciated by those skilled in the art that various changes or equivalent substitutions may be made to these features and embodiments without departing from the spirit and scope of the present invention. In addition, under the teachings of the present invention, these features and embodiments may be modified to adapt to specific circumstances and materials without departing from the spirit and scope of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of the present invention are intended to be protected by the present invention.

Claims

1. A multi-energy cogeneration and energy storage system coupled with compressed air and water, characterized in that: The invention comprises an air compressor (2), a first heat exchanger (3), a second heat exchanger (4) and an air turbine (5) which are connected in sequence, wherein the air compressor (2) is used to compress the introduced air, and the air turbine (5) is coaxially arranged with the air compressor (2). The power generated by the expansion work is used to drive the air compressor (2), and the cooling capacity generated by the expansion work is used to provide cooling to the user through the cooling module. The invention also comprises: A first circulation loop, wherein the circulating medium is molten salt, comprises a low-temperature molten salt tank (10), a first heat exchanger (3), a high-temperature molten salt tank (11), and a third heat exchanger (13) connected end to end in sequence, wherein the first heat exchanger (3) is used to realize heat exchange between the molten salt and the air; The second circulation loop, in which the circulating medium is water, comprises a low-temperature water tank (7), a first booster pump (8), a second heat exchanger (4), a high-temperature water tank (9), a flash tank (12), a third heat exchanger (13) and a steam turbine high-pressure cylinder (14) which are connected in sequence end to end; the first booster pump (8) is used to pressurize the water, the second heat exchanger (4) is used to realize heat exchange between water and air, the flash tank (12) is used to flash the water stored in the high-temperature water tank (9) to obtain steam, the third heat exchanger (13) is used to realize heat exchange between molten salt and steam to increase the temperature of the steam, the power generated by the expansion work of the steam turbine high-pressure cylinder (14) is used to drive the generator to generate electricity, and the waste heat of the steam is used to provide heating to users through the heating module; The cooling module comprises: A refrigeration heat exchanger (6) has a first inlet connected to the outlet of the air turbine (5), a first outlet of the refrigeration heat exchanger (6) connected to the atmosphere, a second inlet and a second outlet of the refrigeration heat exchanger (6) connected to a cooling circulation loop, and a circulating medium in the cooling circulation loop enters the refrigeration heat exchanger (6) for heat exchange and cooling, and then provides cooling to the user; The heating module comprises: The heating heat exchanger (15) has a first inlet connected to the first outlet of the turbine high-pressure cylinder (14), the first outlet of the heating heat exchanger (15) is connected to the first inlet of the low-temperature water tank (7), and the second inlet and the second outlet of the heating heat exchanger (15) are connected to a heating circulation loop. The circulating medium in the heating circulation loop enters the heating heat exchanger (15) for heat exchange and temperature increase to provide heating to the user.

2. A multi-energy cogeneration and energy storage system coupled with compressed air and water according to claim 1, characterized in that: The third inlet of the heating heat exchanger (15) is connected to the flash tank (12) via a first throttle valve (16).

3. The multi-energy cogeneration and energy storage system coupled with compressed air and water according to claim 1, characterized in that: The second outlet of the steam turbine high-pressure cylinder (14) is connected to the inlet of the steam turbine low-pressure cylinder (18). The steam turbine low-pressure cylinder (18) is used to utilize the steam after the steam turbine high-pressure cylinder (14) expands and does work to expand and do work again to generate power to drive the generator to generate electricity. The outlet of the steam turbine low-pressure cylinder (18) is connected to the second inlet of the low-temperature water tank (7). A condenser (19) and a second boosting pump (20) are provided between the steam turbine low-pressure cylinder (18) and the low-temperature water tank (7). The inlet of the condenser (19) is connected to the outlet of the steam turbine low-pressure cylinder (18), the outlet of the condenser (19) is connected to the inlet of the second boosting pump (20), and the outlet of the second boosting pump (20) is connected to the second inlet of the low-temperature water tank (7).

4. The multi-energy cogeneration and energy storage system coupled with compressed air and water according to claim 2, characterized in that: A reheater (17) is provided between the high-pressure cylinder (14) of the steam turbine and the low-pressure cylinder (18) of the steam turbine. The second outlet of the high-pressure cylinder (14) of the steam turbine is connected to the first inlet of the reheater (17). The first outlet of the reheater (17) is connected to the inlet of the low-pressure cylinder (18) of the steam turbine. The second inlet of the reheater (17) is connected to the flash tank (12). A medium-temperature water tank (21) is provided between the reheater (17) and the first booster pump (8). The inlet of the medium-temperature water tank (21) is connected to the second outlet of the reheater (17). The outlet of the medium-temperature water tank (21) is connected to the inlet of the first booster pump (8) through a second throttle valve (23).

5. The multi-energy cogeneration and energy storage system coupled with compressed air and water according to claim 4, characterized in that: A cooler (22) is provided between the medium-temperature water tank (21) and the second throttle valve (23); a first inlet of the cooler (22) is connected to the outlet of the medium-temperature water tank (21); a first outlet of the medium-temperature water tank (21) is connected to the second throttle valve (23); an inlet of the air compressor (2) is connected to the first outlet of the preheater (1); a first inlet of the preheater (1) is connected to the atmosphere; a second inlet of the preheater (1) is connected to the second outlet of the cooler (22); a second outlet of the preheater (1) is connected to the second inlet of the cooler (22); and a third inlet of the preheater (1) is connected to a waste heat source.

6. A multi-energy cogeneration and energy storage system method coupled with compressed air and water, characterized in that: The system according to claim 3 comprises the following steps: Normal temperature and normal pressure air enters the preheater (1) and is preheated to become medium temperature and normal pressure air. The medium temperature and normal pressure air enters the air compressor (2) and is compressed to become high temperature and high pressure air. The high temperature and high pressure air enters the first heat exchanger (3), the second heat exchanger (4), and the air turbine (5) in sequence. The low temperature molten salt enters the first heat exchanger (3) and undergoes heat exchange to become high temperature molten salt, which is stored in the high temperature molten salt tank (11). The low temperature water is pressurized by the first booster pump (8) and enters the second heat exchanger (4) to undergo heat exchange to become medium temperature and high pressure water, which is stored in the high temperature water tank (9). Energy storage is completed. After two heat exchanges, the high temperature and high pressure air expands and performs work in the air turbine (5) and becomes low temperature and normal pressure air. At the same time, the power generated by the expansion work is transmitted to the air compressor (2). The medium-temperature, high-pressure water enters the flash tank (12) for flash evaporation, generating medium-temperature saturated steam and medium-temperature saturated water. The medium-temperature saturated steam enters the third heat exchanger (13) for heat exchange with the high-temperature molten salt to increase its temperature, and then enters the high-pressure cylinder (14) of the steam turbine to expand and perform work, thereby driving the generator to generate electricity. The steam expanded and worked in the high-pressure cylinder (14) of the steam turbine enters the reheater (17), exchanges heat with the medium-temperature saturated water produced by the flash tank (12) to increase its temperature, and then enters the low-pressure cylinder (18) of the steam turbine to expand and work and drive the generator to generate electricity. At the same time, when providing cooling, the low-temperature normal-pressure air expanded and worked by the air turbine (5) enters the refrigeration heat exchanger (6) to provide cooling to the user; During heating, the steam expanded and worked in the high-pressure cylinder (14) of the steam turbine and the medium-temperature saturated water in the flash tank (12) enter the heating heat exchanger (15) to provide heating to the user.

7. A multi-energy cogeneration and energy storage system method coupled with compressed air and water according to claim 6, characterized in that: The temperature of medium-temperature and normal-pressure air is 140℃~160℃ and the pressure is 101.3kPa. The temperature of high-temperature and high-pressure air is 300℃~350℃ and the pressure is 300kPa~400kPa. The temperature of low-temperature and normal-pressure air is -15℃~10℃ and the pressure is 101.3kPa. The temperature of low-temperature water is 25℃~30℃. The temperature of medium-temperature and high-pressure water is 210℃~250℃ and the pressure is 3.5MPa~4.0MPa. The temperature of low-temperature molten salt is 200℃~240℃ and the pressure of high-temperature molten salt is 200℃~240℃. The temperature is 290℃~340℃, the temperature of medium-temperature saturated steam is 190℃~210℃ and the pressure is 1.3MPa~1.9MPa, the temperature of medium-temperature saturated water is 190℃~210℃ and the pressure is 1.3MPa~1.9MPa, the temperature of high-temperature medium-pressure steam is 280℃~330℃ and the pressure is 1.3MPa~1.9MPa, the temperature of medium-temperature atmospheric pressure steam is 100℃~110℃ and the pressure is 101.3kPa, and the temperature of medium-temperature water is 190℃~210℃.

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