Equipment reuse type liquid air energy storage system and method for combined cooling and power supply

Abstract

The invention relates to the technical field of energy storage and comprehensive utilization, in particular to an equipment reuse type liquid air energy storage system and method for combined cooling and power, the system comprises a compression unit, a cold storage unit, an organic Rankine cycle unit, a heat storage unit and an expansion unit, and the system operation is divided into an energy storage stage and an energy release stage. In the energy storage stage, after the environment air is subjected to multi-stage compression, LNG high-grade cold energy is used for assisting liquefaction and storage, medium-grade cold energy drives ORC cycle power generation, and low-grade cold energy precools and compresses inlet air according to needs; and in the energy release stage, liquid air is gasified to drive ORC cycle and an expansion machine to generate power, the cold energy is recycled by the cold storage unit, and the reversible heat exchanger group realizes reuse of interstage cooling and heating functions. Through LNG cold energy gradient utilization, equipment function integration and multi-system cooperation, the problems of equipment redundancy, low efficiency and high cost of an existing system are solved, the comprehensive energy utilization rate and the system stability are improved, and electricity-cold-gas multi-energy combined supply is achieved.

Description

Technical Field

[0001] This invention relates to the field of energy storage and comprehensive utilization technology, and in particular to a reusable liquid air energy storage system and method for combined cooling and power generation. Background Technology

[0002] Liquid compressed air energy storage systems, as an important development direction for large-scale, long-term energy storage technology, play a crucial role in addressing the intermittent generation and consumption of renewable energy, realizing cross-period energy allocation, and ensuring the stability of energy supply. They are also one of the core pieces of equipment supporting the transition of the energy structure towards clean and low-carbon energy. However, in existing technologies, the liquefaction stage relies on electrically driven mechanical refrigeration to provide a low-temperature environment, resulting in insufficient cold energy recovery and utilization. Simultaneously, the compression inlet temperature is constrained by environmental conditions, leading to a significant temperature rise during compression, increasing compression power consumption and cooling requirements. Furthermore, interstage cooling and heating functions require separate dedicated equipment, resulting in redundancy of core equipment and a complex system structure. This not only increases initial investment and operation and maintenance costs but also leads to low cycle efficiency due to multiple losses during energy conversion, severely limiting the widespread application of this type of energy storage system.

[0003] The core issue lies in the fact that existing systems fail to organically combine equipment function reuse, energy cascade utilization, and multi-system synergistic efficiency improvement, leading to a compounded dilemma of equipment redundancy, energy waste, and low system efficiency. To meet the demands of large-scale energy storage scenarios for efficient, low-cost, and multifunctional energy supply, an integrated technical solution is urgently needed. This solution should optimize energy utilization paths and equipment function configurations to overcome the prominent contradictions of low efficiency and high cost in existing systems, and promote the engineering application and industrial development of liquid compressed air energy storage technology. Summary of the Invention

[0004] To overcome the above shortcomings, this invention provides a reusable liquid air energy storage system and method for combined cooling and power generation, aiming to improve the problems of equipment redundancy, insufficient energy utilization, low efficiency and high cost of existing liquid compressed air energy storage systems.

[0005] In a first aspect, the present invention provides the following technical solution: a reusable liquid air energy storage system for combined cooling and power generation, comprising a compression unit, a cold storage unit, an organic Rankine cycle unit, a heat storage unit, and an expansion unit, wherein the system operation includes an energy storage stage and an energy release stage.

[0006] S1, Energy Storage Stage: Ambient air is compressed in multiple stages by the compression unit, and the resulting heat of compression is recovered and stored by the heat storage unit; at the same time, liquefied natural gas (LNG) is output from the LNG receiving station, and after being pressurized by the booster pump, its high-grade cold energy is used to cool the compressed air through the cold box, which assists in its own liquefaction to generate liquid air, which is then stored in the liquid storage tank.

[0007] After releasing high-grade cold energy, LNG is transformed into medium-grade cold energy fluid, which enters the organic Rankine cycle unit to drive power generation, and then transforms into low-grade cold energy fluid; the low-grade cold energy fluid is selectively introduced into the precooler to precool the ambient air according to the inlet air temperature of the compression unit.

[0008] The cold storage medium of the cold storage unit releases cold energy to assist the liquefaction of compressed air in the second cold box. The cold storage medium after the cold energy is released is then stored.

[0009] S2, Energy Release Stage: The liquid air stored in the storage tank is pressurized by the cryogenic pump and enters the evaporator body to vaporize. The cold energy released by its vaporization is recovered and stored by the cold storage unit.

[0010] The vaporized air serves as a cold source and enters the organic Rankine cycle unit to drive it to complete the power generation cycle;

[0011] After generating electricity, the air flows sequentially through the interstage heater, the first interstage common heat exchanger, and the second interstage common heat exchanger, where it is heated step by step by the compression heat stored in the heat storage unit. Then, it enters the first expander, the second expander, and the third expander of the expansion unit to expand and generate electricity step by step.

[0012] By adopting the above technical solutions, comprehensive benefits are improved through multi-dimensional technical design. The core lies in the cascaded and efficient utilization of LNG cold energy. High-grade cold energy assists air liquefaction, medium-grade cold energy drives organic Rankine cycle power generation, and low-grade cold energy pre-cools the compressor inlet air on demand, effectively reducing compression power consumption and improving air liquefaction rate. At the same time, it outputs electricity, supplies cold energy and standard-compliant natural gas, realizing multi-energy supply of electricity, cold energy, and gas, and fully tapping the value of energy. With the reversible heat exchanger group, the interstage cooling function of the energy storage stage and the interstage heating function of the energy release stage are integrated into one set of equipment, eliminating the need for separate dedicated heating heat exchangers, significantly reducing the number of core system equipment, reducing initial investment and operation and maintenance costs, and improving equipment utilization. Furthermore, cold energy is recycled and recovered through the cold storage unit. The organic Rankine cycle dual system recovers energy of different grades respectively. With highly adaptable working fluids and media, the comprehensive energy utilization rate of the system is further improved, ensuring overall operational stability and forming a functionally synergistic and efficiency-optimized energy storage and supply system.

[0013] Preferably, the compression unit includes a precooler, compressor one, compressor two, compressor three, interstage common heat exchanger one, interstage common heat exchanger two, interstage cooler, cryogenic expander, gas-liquid separator, and cold box first channel, cold box second channel, and cold box third channel;

[0014] During the energy storage stage, ambient air first enters the precooler, and after precooling, it flows sequentially through compressor one, interstage common heat exchanger one, compressor two, interstage common heat exchanger two, compressor three, and interstage cooler to complete multi-stage compression.

[0015] The compressed high-pressure air enters the first cold box through the second cold box channel. After exchanging heat with the high-grade cold energy of LNG, it enters the second cold box for further cooling. Then, it is expanded, cooled, and depressurized by the cryogenic expander and enters the gas-liquid separator to be separated into liquid air and unliquefied cold air.

[0016] Unliquefied cold air returns to cold box one through the second channel of the heat exchanger and returns to cold box two through the third channel of the cold box, releasing cold energy. After releasing cold energy, it mixes with the replenished ambient air and returns to the inlet of the precooler.

[0017] Interstage shared heat exchanger one, interstage shared heat exchanger two, and interstage cooler transfer the heat of compression to the high-temperature tank of the heat storage unit, and the heat exchanged medium is stored in the low-temperature tank.

[0018] Preferably, the cold storage unit includes a cold storage tank, a heat storage tank, an evaporator body, and a third heat exchanger channel;

[0019] During the energy storage stage, the unliquefied cold air separated by the gas-liquid separator (17) passes through the second channel (14) of the heat exchanger, and the cold storage medium in the cold storage tank (21) passes through the third channel (15) of the heat exchanger and enters the second cold box (12) to release cold energy to assist air liquefaction. The cold storage medium after the cold is released is stored in the heat storage tank (22).

[0020] During the energy release phase, the cold storage medium in the heat storage tank (22) enters the evaporator body (20), heats and vaporizes the liquid air, and then returns to the heat storage tank (22) for storage.

[0021] Preferably, the first interstage shared heat exchanger and the second interstage shared heat exchanger are reversible heat exchanger groups.

[0022] During the energy storage stage, the flow path is controlled by the regulating valve. Interstage common heat exchanger one and interstage common heat exchanger two serve as heat exchangers to perform interstage cooling functions, cooling the compressed air at the outlets of compressor one and compressor two respectively. Together with the independently set interstage cooler, they transfer the recovered compressed heat to the high-temperature tank.

[0023] During the energy release phase, the flow path is switched in reverse by the regulating valve. The interstage shared heat exchanger 1 and interstage shared heat exchanger 2 serve as heat exchangers to perform the interstage heating function, using the heat stored in the high-temperature tank to heat the air before expansion.

[0024] Preferably, a temperature sensor is provided at the inlet of the compressor;

[0025] During the energy storage phase, a temperature sensor is used to detect the inlet air temperature. When the detected temperature is higher than the set temperature, low-grade cold energy fluid from the organic Rankine cycle unit is introduced into the precooler to precool the air. The flow rate of the low-grade cold energy fluid is dynamically adjusted by a regulating valve to maintain a constant inlet air temperature of the compressor. The precooled and vaporized natural gas is then supplied to the outside.

[0026] Preferably, the organic Rankine cycle unit includes a first cycle subsystem and a second cycle subsystem;

[0027] The second cycle subsystem includes an ORC evaporator, an ORC expander II, an ORC condenser II, and an ORC pump II, and operates during the energy storage phase.

[0028] The first cycle subsystem includes an ORC condenser, an ORC pump, an ORC first evaporator, an ORC second evaporator, and an ORC expander, and operates during the energy release phase.

[0029] The working fluid of the organic Rankine cycle unit is propane or R134a; the cold storage medium of the cold storage unit is propane or nitrogen; the heat storage and exchange medium of the heat storage unit is pressurized water, heat transfer oil or molten salt; the ORC pump pressurizes the working fluid of the first circulation subsystem to above 10 MPa.

[0030] Preferably, during the energy storage phase, the medium-grade cold energy fluid formed after the LNG releases high-grade cold energy enters the ORC condenser II to provide cooling for the working fluid of the second cycle subsystem.

[0031] The working fluid of the second circulation subsystem absorbs heat and evaporates in the ORC evaporator, driving the ORC expander II to generate electricity. After doing work, the working fluid enters the ORC condenser II, releases waste heat to the medium-grade cold energy fluid, and condenses into a liquid state. The condensed working fluid is pressurized by the ORC pump II and returns to the ORC evaporator to complete the cycle. The medium-grade cold energy fluid absorbs waste heat and transforms into a low-grade cold energy fluid, which is used for air precooling in the precooler.

[0032] Preferably, during the energy release phase, the vaporized air serves as a cold source flowing through ORC condenser one to cool the working fluid of the first cycle subsystem.

[0033] The working fluid of the first cycle subsystem is cooled by the ORC condenser and pressurized by the ORC pump, and then flows through the ORC first evaporator and the ORC second evaporator to absorb heat.

[0034] The heat source for the first ORC evaporator is room temperature water, and the heat source for the second ORC evaporator is the residual compression heat stored in the high-temperature tank. After absorbing heat, the working fluid forms superheated steam, which drives the ORC expander to generate electricity. The working fluid that has done work returns to the ORC condenser to complete the cycle.

[0035] Ideally, the initial temperature of the LNG output from the LNG receiving terminal is -162℃, and the booster pump pressurizes it to 7MPa; the ORC first evaporator absorbs the cold energy and can then provide cold energy to the outside.

[0036] Secondly, the present invention provides the following technical solution: a method for reusable liquid air energy storage in combined cooling and power (CCHP) systems, comprising the following steps:

[0037] S1. Ambient air is compressed in multiple stages by the compression unit, and the heat of compression generated is recovered and stored by the heat storage unit. At the same time, the high-grade cold energy of liquefied natural gas (LNG) is introduced through the cold box to cool the compressed high-pressure air to assist its liquefaction. The generated liquid air is stored in the storage tank. After releasing the high-grade cold energy, the high-grade cold energy is used to drive the second power generation cycle of the organic Rankine cycle unit. After power generation, the LNG is converted into low-grade cold energy and selectively introduced into the precooler to precool the ambient air according to the inlet air temperature of the compression unit.

[0038] S2. The stored liquid air is pressurized and vaporized by a cryogenic pump. The cold energy released during the vaporization process is recovered and stored by the cold storage unit. The vaporized air serves as a cold source and enters the organic Rankine cycle unit to drive its first power generation cycle. Subsequently, the air passes through the interstage heater and the interstage common heat exchanger 2 and interstage common heat exchanger 1 with reverse switching flow paths. It is heated step by step by the compression heat stored in the heat storage unit and finally introduced into the first expander, second expander and third expander of the expansion unit to expand step by step and generate electricity.

[0039] The present invention has the following beneficial effects:

[0040] 1. In this invention, by utilizing LNG cold energy in stages, high-grade cold energy assists in air liquefaction, medium-grade cold energy drives organic Rankine cycle power generation, and low-grade cold energy pre-cools the compressor inlet air as needed, effectively reducing compression power consumption and improving air liquefaction rate and system efficiency; at the same time, the system can output electricity, supply cold energy and standard-compliant natural gas, realize multi-energy supply of electricity, cooling and gas, fully explore the value of energy, and expand application scenarios.

[0041] 2. In this invention, a reversible heat exchanger group is used to perform interstage cooling function in the energy storage stage and switch to interstage heating function in the energy release stage. The two functions are integrated into one set of equipment, eliminating the need for a separate dedicated heating heat exchanger. This significantly reduces the number of core equipment in the system, lowers the initial investment and subsequent operation and maintenance costs, while improving the utilization efficiency of core equipment and optimizing the overall system layout.

[0042] 3. In this invention, the cold energy of the cold storage unit is recycled to assist in the liquefaction of air and recover the cold energy of liquid air vaporization, thereby reducing the waste of cold energy; the organic Rankine cycle dual system recovers medium-grade cold energy and residual compression heat and low-grade heat energy respectively, realizing the efficient recovery of energy of different grades. With the combination of highly adaptable working fluid and medium, the overall energy utilization rate of the system is further improved and the operational stability is guaranteed. Attached Figure Description

[0043] Figure 1 This is a flowchart of the equipment reuse liquid air energy storage system for combined cooling and power generation proposed in this invention.

[0044] The components are as follows: 1. Precooler; 2. Compressor 1; 4. Compressor 2; 6. Compressor 3; 3. Interstage common heat exchanger 1; 5. Interstage common heat exchanger 2; 7. Interstage cooler; 8. Cold box 1; 12. Cold box 2; 9. Cold box first channel; 10. Cold box second channel; 11. Cold box third channel; 13. Heat exchanger first channel; 14. Heat exchanger second channel; 15. Heat exchanger third channel; 16. Cryogenic expander; 17. Gas-liquid separator; 18. Liquid storage tank; 19. Cryogenic pump; 20. Evaporator body; 21. Cold storage tank. 22. Heat storage tank; 23. ORC condenser I; 24. ORC pump I; 25. ORC second evaporator; 26. ORC expander I; 27. ORC first evaporator; 28. Control valve; 29. ​​Interstage heater; 31. First expander; 32. Second expander; 33. Third expander; 34. Cryogenic tank; 35. High-temperature tank; 36. LNG receiving station; 37. Booster pump; 38. Temperature sensor; 39. ORC expander II; 40. ORC condenser II; 41. ORC pump II; 42. ORC evaporator. Detailed Implementation

[0045] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0046] Example 1

[0047] In embodiments of the present invention, the present invention provides a reusable liquid air energy storage system for combined cooling and power generation, such as... Figure 1 As shown, it includes a compression unit, a cold storage unit, an organic Rankine cycle unit, a heat storage unit, and an expansion unit. The system operation includes an energy storage stage and an energy release stage.

[0048] S1, Energy Storage Stage: Ambient air is compressed in multiple stages by the compression unit, and the heat generated by compression is recovered and stored by the heat storage unit; at the same time, liquefied natural gas (LNG) is output from LNG receiving station 36, and after being pressurized by booster pump 37, its high-grade cold energy is used to cool the compressed air through cold box 8, which assists in its own liquefaction to generate liquid air, and the liquid air is stored in storage tank 18.

[0049] After releasing high-grade cold energy, the LNG is transformed into a medium-grade cold energy fluid. This medium-grade cold energy fluid enters the organic Rankine cycle unit to drive power generation, and then transforms into a low-grade cold energy fluid. The low-grade cold energy fluid is selectively introduced into the precooler 1 to precool the ambient air according to the inlet air temperature of the compression unit.

[0050] The cold storage medium in the cold storage unit releases cold energy to assist the liquefaction of compressed air in the cold box 12. The cold storage medium after the cold energy is released is then stored.

[0051] S2, Energy Release Stage: The liquid air stored in the storage tank 18 is pressurized by the cryogenic pump 19 and enters the evaporator body 20 to vaporize. The cold energy released by its vaporization is recovered and stored by the cold storage unit.

[0052] The vaporized air serves as a cold source and enters the organic Rankine cycle unit to drive it to complete the power generation cycle;

[0053] After generating electricity, the air flows sequentially through the interstage heater 29, the interstage common heat exchanger 25, and the interstage common heat exchanger 3. After being heated step by step by the compression heat stored in the heat storage unit, it enters the first expander 31, the second expander 32, and the third expander 33 of the expansion unit in sequence to expand and generate electricity.

[0054] Specifically, the precooler 1 initially cools the ambient air entering the compression unit, reducing its initial temperature and thus minimizing power consumption during subsequent compression. The precooled air is then progressively compressed in stages by compressors 2, 4, and 6, gradually increasing the air pressure to meet liquefaction requirements and creating the necessary pressure conditions for liquefaction. Interstage heat exchangers 3 and 5 switch to cooling mode during compression, cooling the high-temperature compressed air exiting compressors 2 and 4 respectively. Simultaneously, interstage cooler 7 further cools the air exiting compressor 6, efficiently recovering the large amount of heat generated during compression. This recovered heat is then transferred to the high-temperature tank 35 of the heat storage unit for storage, reserving energy for the heating process during energy release. The low-temperature heat exchange medium after heat exchange is stored in the low-temperature tank 34 for later use. The LNG is then fed through a booster pump 37. The cryogenic LNG output from station 36 is pressurized to increase the LNG pressure to meet the system's heat exchange pressure requirements, thereby ensuring that high-grade cold energy can stably and efficiently participate in the air cooling process. Cold box 8 provides a heat exchange space for compressed air and LNG cold energy. The high-grade LNG cold energy in the cold box fully contacts and exchanges heat with the high-pressure air, rapidly reducing the air temperature and providing sufficient cold source for air liquefaction. Cryogenic expander 16 expands the cooled high-pressure air, further reducing the air temperature and pressure, thus promoting liquefaction. Gas-liquid separator 17 separates the expanded gas-liquid mixture, filtering out liquid air and separating unliquefied cold air, ensuring the purity of the liquid air. Unliquefied cold air can be returned to the cold box for reuse. Storage tank 18 seals and stores the separated liquid air, preserving liquefied energy and enabling cross-period energy storage.

[0055] The ORC condenser 40 in the Organic Rankine Cycle unit exchanges heat with the medium-grade cold energy fluid of LNG, providing cooling for the working fluid in the second cycle subsystem and promoting its condensation. This, in turn, works with the ORC evaporator 42 to absorb heat and vaporize the working fluid, providing power for power generation. The ORC expander 39 uses the vaporized high-pressure working fluid to drive the impeller, converting heat energy into electrical energy, thus recovering and utilizing medium-grade cold energy. The ORC condenser 40 condenses the exhaust working fluid after work, restoring it to a liquid state for recycling, ensuring the continuous and stable operation of the Organic Rankine Cycle. The ORC pump... The compressor evaporator 41 pressurizes and transports the condensed liquid working fluid, returning it to the ORC evaporator 42 to participate in heat exchange again, thus forming a closed-loop cycle. The temperature sensor 38 monitors the air temperature at the inlet of compressor 2 in real time, accurately sensing temperature changes and providing a signal for cold energy regulation. The regulating valve 28 dynamically controls the flow rate of low-grade cold energy fluid based on the signal from the temperature sensor 38, distributing cold energy as needed and ensuring that the inlet temperature of compressor 2 is maintained within the set range. This prevents increased compression power consumption due to excessively high ambient temperatures. At the same time, the natural gas vaporized from the pre-cooled low-grade cold energy fluid can be directly supplied externally, achieving multi-energy supply.

[0056] The cold storage tank 21 stores the cold storage medium to be released, which serves as a cold energy reserve and provides a stable cold source for auxiliary liquefaction. The third channel 15 of the heat exchanger provides a heat exchange channel between the cold storage medium and the compressed air in the second cold box 12, which serves to transfer cold energy and help the LNG cold energy reduce the air temperature and improve liquefaction efficiency. The heat storage tank 22 collects and stores the cold storage medium after the cold is released, which serves to recover the medium after the cold is released and keep it for later use. This lays the foundation for subsequent cold energy recovery and recycling, realizes the recycling of cold energy, reduces cold energy waste, and reduces the additional cooling energy consumption in the energy storage stage.

[0057] The cryogenic pump 19 pressurizes the liquid air in the storage tank 18, increasing the pressure to meet the subsequent vaporization and expansion requirements, thus laying the foundation for energy output in the energy release stage. The evaporator body 20 provides a vaporization space for the liquid air and the cold storage medium. The liquid air absorbs heat and vaporizes in the evaporator, converting the stored liquid energy into gaseous energy, thereby releasing energy. The third channel 15 of the heat exchanger transfers the cold energy released during the vaporization of the liquid air, allowing the cold storage medium to absorb the cold energy, which is then recovered and stored in the heat storage tank 22. This allows the cold storage medium to carry cold energy again, providing a cold source for the auxiliary liquefaction in the next energy storage stage, forming a cold energy cycle and improving the system's energy utilization rate.

[0058] The ORC condenser 23 allows the vaporized air to exchange heat with the working fluid of the first subsystem of the Organic Rankine Cycle, cooling the working fluid and providing a cold source for its condensation, thus ensuring stable circulation. The ORC pump 24 pressurizes the condensed liquid working fluid, increasing its pressure to meet heat exchange and expansion requirements, providing high-pressure working fluid for power generation. The ORC first evaporator 27 absorbs heat from room-temperature water, heating the working fluid and recovering low-grade heat energy. The ORC second evaporator 25 absorbs residual compression heat stored in the high-temperature tank 35 of the heat storage unit, further increasing the working fluid's temperature and pressure, thus enhancing its expansion and work-generating capacity. The ORC expander 26 utilizes the high-temperature, high-pressure working fluid to convert heat energy into electrical energy, achieving full recovery of system waste heat and improving overall energy conversion efficiency.

[0059] The interstage heater 29 utilizes the compression heat in the high-temperature tank 35 to initially heat the air, raising its initial temperature and laying the foundation for subsequent staged heating. The regulating valve 28 reverses the flow path, switching the interstage common heat exchangers 5 and 3 from cooling mode to heating mode, further raising the air temperature and enthalpy through the heat from the high-temperature tank 35, thus enhancing the air's ability to expand and perform work. The first expander 31, second expander 32, and third expander 33 progressively expand the high-temperature, high-pressure air, gradually converting its internal energy into mechanical energy and then further into electrical energy, achieving efficient energy output. The multi-stage expansion design avoids energy loss from single expansions, improving system energy release efficiency and ultimately achieving a complementary supply of cooling, electricity, and gas to meet energy needs in different scenarios.

[0060] Furthermore, the compression unit includes a precooler 1, compressor one 2, compressor two 4, compressor three 6, interstage common heat exchanger one 3, interstage common heat exchanger two 5, interstage cooler 7, cryogenic expander 16, gas-liquid separator 17, and cold box first channel 9, cold box second channel 10, cold box third channel 11, heat exchanger first channel 13, and heat exchanger second channel 14;

[0061] During the energy storage stage, ambient air first enters the precooler 1, and after precooling, it flows sequentially through compressor 1 2, interstage common heat exchanger 1 3, compressor 2 4, interstage common heat exchanger 2 5, compressor 3 6, and interstage cooler 7 to complete multi-stage compression.

[0062] The compressed high-pressure air enters the first cold box 8 through the second cold box channel 10. After exchanging heat with the high-grade cold energy of LNG, it enters the second cold box 12 through the third cold box channel 11 for further cooling. Then, it is expanded, cooled and depressurized by the cryogenic expander 16 and enters the gas-liquid separator 17 to be separated into liquid air and unliquefied cold air.

[0063] Unliquefied cold air returns to cold box 1 8 through the second channel 14 of the heat exchanger and returns to cold box 2 12 through the third channel 11 of the cold box to release cold energy. After releasing cold energy, it mixes with the replenished ambient air and returns to the inlet of precooler 1.

[0064] Interstage shared heat exchanger 3, interstage shared heat exchanger 5 and interstage cooler 7 transfer the heat of compression to the high-temperature tank 35 of the heat storage unit, and the heat exchange medium after heat exchange is stored in the low-temperature tank 34.

[0065] Specifically, in the energy storage stage, ambient air first enters precooler 1, and after precooling, it flows sequentially through compressor 1 2, interstage common heat exchanger 1 3, compressor 2 4, interstage common heat exchanger 2 5, compressor 3 6, and interstage cooler 7 to complete multi-stage compression. Precooler 1 pre-cools the ambient air, reducing its initial temperature and thus decreasing the compression load and energy consumption of subsequent compressors. Compressors 1 2, 2 4, and 3 6 compress the air at progressively increasing pressure levels, gradually raising the air pressure to the pressure required for liquefaction, thus providing core pressure assurance for air liquefaction. Interstage common heat exchangers 1 3 and 2 5 switch to cooling between compression stages. In the cooling mode, the high-temperature compressed air discharged from compressor 2 and compressor 4 is cooled respectively, which removes the heat of compression in time and avoids the air temperature from affecting the compression efficiency, thus ensuring the stable and efficient operation of the multi-stage compression process. The high-pressure air at the outlet of compressor 6 is finally cooled by interstage cooler 7, which further reduces the air temperature and recovers the heat of compression at the end, thus laying the temperature foundation for the air to enter the cold box for heat exchange. The compressed high-pressure air enters cold box 8 through the second cold box channel 10. The second cold box channel 10 guides the high-pressure air to flow through the heat exchange area of ​​cold box 8, thus ensuring that the air and the high-grade cold energy of LNG are fully contacted. After the air exchanges heat with the high-grade cold energy of LNG, The air enters the second cold box 12 through the third channel 11 of the cold box for further cooling. The third channel 11 connects the first cold box 8 and the second cold box 12, guiding the air to continuously participate in deep cooling, thereby gradually reducing the air temperature to near the liquefaction point. The cooled air then passes through the low-temperature expander 16 for expansion, cooling, and depressurization. Through the adiabatic expansion of the low-temperature expander 16, the air temperature and pressure are rapidly reduced, promoting the air to reach a saturated liquefaction state, thus significantly increasing the air liquefaction rate. The expanded gas-liquid mixture enters the gas-liquid separator 17 to be separated into liquid air and unliquefied cold air. Through the separation action of the gas-liquid separator 17, high-purity liquid air is screened out and unliquefied gaseous components are separated, thus... To ensure the storage quality of the energy storage medium, unliquefied cold air returns to cold box 8 through the second channel 14 of the heat exchanger and to cold box 12 through the third channel 11 of the cold box, releasing its cold energy. The second channel 14 of the heat exchanger guides the unliquefied cold air back to cold box 8, while the third channel 11 simultaneously facilitates the return of unliquefied cold air to cold box 12. Together, they recover the cold energy in the unliquefied air and reuse it in the air cooling process, thereby reducing cold energy waste. After releasing its cold energy, the unliquefied cold air mixes with the replenished ambient air and returns to the inlet of the precooler 1, serving to recycle the unliquefied air and replenish the system's air supply, thereby improving air utilization and reducing the system's dependence on external air.Interstage shared heat exchanger 3, interstage shared heat exchanger 5, and interstage cooler 7 simultaneously recover compression heat during the cooling process, transferring the compression heat to the high-temperature tank 35 of the heat storage unit. This efficiently recovers the heat energy generated during compression and stores it, providing energy support for air heating during the energy release phase. The low-temperature heat exchange medium after heat exchange is stored in the low-temperature tank 34, serving to store the low-temperature medium and prepare it for the next round of compression heat recovery cycle, thus ensuring the stable operation of the heat storage unit.

[0066] Furthermore, the cold storage unit includes a cold storage tank 21, a heat storage tank 22, an evaporator body 20, and a third heat exchanger channel 15;

[0067] During the energy storage stage, the unliquefied cold air separated by the gas-liquid separator 17 passes through the second channel 14 of the heat exchanger, and the cold storage medium in the cold storage tank 21 passes through the third channel 15 of the heat exchanger and enters the cold box 12 to release cold energy to assist air liquefaction. The cold storage medium after releasing cold energy is stored in the heat storage tank 22.

[0068] During the energy release phase, the cold storage medium in the heat storage tank 22 enters the evaporator body 20, heats and vaporizes the liquid air, and then returns to the heat storage tank 22 for storage.

[0069] Specifically, during the energy storage phase, the cold storage tank 21 serves as a storage container for the cold storage medium. By storing the cold storage medium to be released, it provides a stable cold source reserve for auxiliary air liquefaction, thereby preventing the interruption of cold energy supply from affecting liquefaction efficiency. The unliquefied cold air separated by the gas-liquid separator 17 enters the cold box 12 simultaneously through the second channel 14 of the heat exchanger and the cold storage medium in the cold storage tank 21 through the third channel 15 of the heat exchanger. The third channel 15 of the heat exchanger and the second channel 14 of the heat exchanger form a coordinated heat exchange path, which guides the cold storage medium and the unliquefied cold air in a directional manner. The role of the cooled air flowing through the heat exchange area of ​​cold box 12 is to ensure that both the cooled air and the high-pressure air are in full contact, thereby efficiently transferring cold energy. The cold storage medium releases cold energy in cold box 12, and the unliquefied cooled air releases residual cold energy at the same time. The two work together to assist the high-grade cold energy of LNG in lowering the air temperature, making up for the insufficient cooling capacity of a single cold source, thereby significantly improving the air liquefaction rate and liquefaction rate. The cooled medium after the cold is released is stored in the heat storage tank 22. The heat storage tank 22 plays the role of collecting and storing the cold storage medium in a low-cold state, preventing the medium from being lost, and thus laying the foundation for subsequent cold energy recovery and recycling.

[0070] During the energy release phase, the cold storage medium in the heat storage tank 22 is introduced into the evaporator body 20. The evaporator body 20 provides a heat exchange and vaporization space for the cold storage medium and liquid air, serving as a platform for cold energy transfer and air vaporization, thereby ensuring the orderly progress of the vaporization process. The cold storage medium absorbs the cold energy released by the vaporization of liquid air within the evaporator body, effectively capturing cold energy and thus achieving cold energy recovery and reuse. After absorbing cold energy, the cold storage medium carries the recovered cold energy back to the heat storage tank 22 for storage, serving as a means to re-store the recovered cold energy and provide a cold source for the next energy storage phase, forming a closed loop of cold energy recycling and reducing cold energy waste. At the same time, the liquid air is heated and vaporized by the cold storage medium during the release of cold energy, converting the stored liquid energy into gaseous energy, thereby providing a gaseous working fluid for subsequent organic Rankine cycle power generation and expansion power generation, ensuring continuous energy output during the energy release phase.

[0071] Furthermore, the interstage shared heat exchanger 3 and the interstage shared heat exchanger 5 are reversible heat exchanger assemblies.

[0072] During the energy storage stage, the flow path is controlled by regulating valve 28. Interstage common heat exchanger 1 3 and interstage common heat exchanger 2 5 serve as heat exchangers to perform interstage cooling functions, respectively cooling the compressed air at the outlet of compressor 1 2 and compressor 2 4. Together with the independently set interstage cooler 7, they transfer the recovered compressed heat to the high-temperature tank 35.

[0073] During the energy release phase, the flow path is switched in reverse by regulating valve 28. Interstage common heat exchanger 3 and interstage common heat exchanger 5 serve as heat exchangers to perform interstage heating functions, using the heat stored in high-temperature tank 35 to heat the air before expansion.

[0074] Specifically, the interstage shared heat exchanger 3 and the interstage shared heat exchanger 5 are reversible heat exchanger groups. Their core advantage is that they can switch functions according to the system operation stage, and achieve both cooling and heating functions through a set of equipment, thereby reducing the number of dedicated heat exchangers and reducing system equipment costs and space occupation.

[0075] During the energy storage stage, the regulating valve 28, as the core component of the flow path control, guides the heat exchange medium through the cooling channels of the interstage common heat exchanger 3 and the interstage common heat exchanger 5 by precisely adjusting the switching of internal channels, thereby enabling the two to stably switch to perform interstage cooling functions. The interstage common heat exchanger 3 specifically cools the high-temperature compressed air at the outlet of compressor 2, while the interstage common heat exchanger 5 cools the compressed air at the outlet of compressor 4. The two precisely match the cooling requirements of the first two compression stages, playing a role in directional removal of compression heat and preventing the cumulative increase of air temperature, thereby ensuring the efficiency and stability of each compression process. At the same time, these two heat exchangers, together with the independently set interstage cooler 7, form a collaborative cooling system. The interstage cooler 7 undertakes the task of cooling the air after the third stage compression. The three together cover the entire process of compression heat recovery, maximizing the recovery of heat energy generated during compression. The centrally recovered compression heat is then efficiently transferred to the high-temperature tank 35 of the heat storage unit for storage, providing sufficient energy for air heating during the energy release stage and avoiding heat energy waste.

[0076] During the energy release phase, the regulating valve 28 again plays the role of flow path switching. By reversing the flow direction of the internal medium, it switches the interstage common heat exchanger 3 and the interstage common heat exchanger 5 from cooling mode to heating mode, thereby realizing the reversible conversion of equipment function. The two heat exchangers after switching, as the core components for performing interstage heating function, are connected to the heat exchange medium circulation of the high-temperature tank 35. They use the stored compression heat to heat the air before expansion step by step, thereby gradually increasing the air temperature and enthalpy value, thereby enhancing the air's ability to do work in the expander and reducing energy loss. At the same time, it forms a complementary heating system with the independent interstage heater 29 to ensure that the air is heated to the optimal temperature for expansion and work, ultimately improving the energy conversion efficiency and power generation stability of the system during the energy release phase.

[0077] Furthermore, a temperature sensor 38 is installed at the inlet of compressor 12;

[0078] During the energy storage phase, temperature sensor 38 is used to detect the inlet air temperature. When the detected temperature is higher than the set temperature, low-grade cold energy fluid from the organic Rankine cycle unit is introduced into the precooler 1 to precool the air. The flow rate of the low-grade cold energy fluid is dynamically adjusted by regulating valve 28 to maintain a constant inlet air temperature of compressor 2. The precooled and vaporized natural gas is then supplied to the outside.

[0079] Specifically, a temperature sensor 38 is installed at the inlet of compressor 2. As a real-time monitoring component for the inlet air temperature, the temperature sensor 38 continuously collects air temperature data at the inlet of compressor 2 to accurately capture fluctuations in ambient air temperature, thereby providing timely and reliable signal basis for cooling energy regulation and avoiding imbalance of compression conditions due to lag in temperature monitoring.

[0080] During the energy storage phase, the detection data from temperature sensor 38 is directly used as the criterion for judging the cold energy supply. When the inlet air temperature is detected to be 25°C higher than the set temperature, the system starts the low-grade cold energy utilization process. The low-grade cold energy fluid from the organic Rankine cycle unit, after being heated by the LNG derivative fluid in ORC condenser 2 40, is introduced into precooler 1. The residual cold energy carried by the low-grade cold energy fluid is fully exchanged with the ambient air through precooler 1, which plays the role of using waste cold energy to reduce the inlet air temperature of the compressor, thereby making up for the problem of insufficient precooling and reducing the extra power consumption of the compressor due to excessively high inlet temperature. The regulating valve 28 and temperature sensor 38 form a closed-loop control system. By receiving the real-time signal from temperature sensor 38, the flow rate of the low-grade cold energy fluid is dynamically adjusted. When the temperature is too high, the flow rate is increased, and when the temperature reaches the standard, the flow rate is decreased. This plays the role of distributing cold energy on demand and accurately controlling the precooling intensity, thereby ensuring that the inlet air temperature of compressor 2 is stably maintained at the set value, ensuring that the compressor always operates in the optimal compression condition, improving compression efficiency and extending the service life of the equipment.

[0081] Meanwhile, after releasing cold energy in the precooler 1, the low-grade cold energy fluid is completely vaporized into natural gas that meets the supply standards. This natural gas is directly supplied to the outside world, which plays a role in fully recovering the residual energy of LNG and realizing the complementary supply of cold, electricity and gas, thereby improving the overall energy utilization rate of the system, expanding the application scenarios of the system and avoiding energy waste.

[0082] Furthermore, the organic Rankine cycle unit includes a first cycle subsystem and a second cycle subsystem;

[0083] The second cycle subsystem includes ORC evaporator 42, ORC expander II 39, ORC condenser II 40 and ORC pump II 41, which operate during the energy storage phase;

[0084] The first cycle subsystem includes ORC condenser 23, ORC pump 24, ORC first evaporator 27, ORC second evaporator 25, and ORC expander 26, and operates during the energy release phase.

[0085] Specifically, the Organic Rankine Cycle unit adopts a design where the first and second cycle subsystems operate independently, respectively adapting to the energy recovery needs of the energy release and energy storage stages. This allows for the utilization of cold and heat energy in different time periods and at different quality levels, thereby avoiding the problem that a single cycle cannot adequately address the energy characteristics of different stages and maximizing the system's energy recovery efficiency. The second cycle subsystem includes an ORC evaporator 42, an ORC expander II 39, an ORC condenser II 40, and an ORC pump II 41, which operate specifically during the energy storage stage. The first cycle subsystem includes an ORC condenser I 23, an ORC pump I 24, an ORC first evaporator 27, an ORC second evaporator 25, and an ORC expander I 26, which operate specifically during the energy release stage.

[0086] During the energy storage phase, ORC condenser 2 (40) serves as the core component of the cold source for the second cycle subsystem. It provides an interface between the circulating working fluid and the medium-grade cold energy fluid in the LNG, absorbing cold energy and evaporating the liquid working fluid into high-pressure steam, thus providing sufficient power for the power generation process. ORC expander 2 (39) receives the high-pressure steam output from ORC evaporator 42 and uses the expansion force of the steam to drive the internal impeller to rotate at high speed, converting the thermal energy of the working fluid into mechanical energy and further into electrical energy. This achieves the resource utilization of medium-grade cold energy in the LNG, avoiding the need for medium-grade cold energy to be stored in the LNG. The waste caused by direct discharge of cold energy; ORC condenser 2 40 receives the exhaust working fluid discharged from ORC expander 2 39, and cools the exhaust steam and condenses the working fluid into a liquid state by exchanging heat with medium-grade cold energy fluid, thereby creating conditions for the recycling of the working fluid and ensuring the continuous operation of the second circulation subsystem; ORC pump 2 41, as the power transmission component of the second circulation subsystem, pressurizes the condensed liquid working fluid and accurately pushes the working fluid back to ORC evaporator 42 to participate in heat exchange again, thereby forming a closed loop, reducing working fluid loss and lowering system operating costs.

[0087] During the energy release phase, ORC condenser 23, serving as the cold source heat exchange component of the first cycle subsystem, cools the circulating working fluid by allowing the vaporized air to flow through its internal channels, condensing the working fluid into a liquid state. This lays the foundation for the pressurized circulation of the working fluid and simultaneously achieves the initial recovery of the cold energy from the vaporized air. ORC pump 24, by high-pressure transporting the condensed liquid working fluid, increases the working fluid pressure and meets the subsequent evaporator heat exchange temperature requirements, ensuring that the working fluid can fully absorb heat to form high-pressure superheated steam. ORC first evaporator 27, by absorbing the low-grade heat energy from room temperature water, initially heats the working fluid and increases its pressure. The working fluid temperature plays a role in expanding the system's energy sources and enabling the recovery and utilization of low-grade heat energy. The ORC second evaporator 25 further absorbs the residual compression heat stored in the high-temperature tank 35 of the heat storage unit, heating the working fluid to a superheated steam state and significantly increasing its enthalpy value, thereby enhancing the working fluid's work capacity in the expander. The ORC expander 26 receives the high-temperature, high-pressure superheated steam output from the ORC second evaporator 25 and uses the steam expansion to drive power generation, efficiently converting the working fluid's heat energy into electrical energy, thereby achieving deep recovery of the system's waste heat and significantly improving the overall energy conversion efficiency of the entire energy storage combined cooling and power system.

[0088] Furthermore, the working fluid of the organic Rankine cycle unit is propane or R134a; the cold storage medium of the cold storage unit is propane or nitrogen; the heat storage and exchange medium of the heat storage unit is pressurized water, heat transfer oil or molten salt; the ORC pump-24 pressurizes the working fluid of the first cycle subsystem to above 10 MPa.

[0089] Specifically, the Organic Rankine Cycle (ORC) unit uses propane or R134a as the working fluid. These two working fluids have the characteristics of low boiling point, good thermal stability, and moderate latent heat of phase change. By adapting to the temperature range of cold energy and waste heat in the system, they play a role in rapid heat absorption and evaporation in the ORC evaporator and efficient condensation and reflux in the condenser, thereby ensuring the thermodynamic efficiency of the ORC cycle and avoiding energy loss caused by mismatch of working fluid characteristics. At the same time, both working fluids have the advantages of being environmentally friendly and having low toxicity, improving the safety and environmental protection of the system operation. The cold storage unit uses propane or nitrogen as the cold storage medium. Propane, with its large latent heat of phase change, achieves high-density storage and rapid transfer of cold energy through the phase change process. Nitrogen has the advantages of chemical stability, wide availability, and low cost. It achieves stable storage of cold energy through sensible heat exchange. The two can be selected as needed to flexibly adapt to different cold energy storage requirements, thereby ensuring that the cold storage unit efficiently assists air liquefaction in the energy storage stage and fully recovers cold energy in the energy release stage, improving the cold energy recycling rate.

[0090] The heat storage unit uses pressurized water, thermal oil, or molten salt as the heat storage and exchange medium. Pressurized water has a large specific heat capacity, high heat transfer efficiency, and extremely low cost, making it suitable for heat storage and transfer in the medium and low temperature range. Thermal oil is resistant to high temperatures and does not easily vaporize, making it suitable for storing compression heat at higher temperatures. Molten salt has the characteristics of high heat storage density and a wide operating temperature range, which can meet the long-term storage requirements of large capacity and high-grade heat. Through the flexible adaptation of the three media, it plays the role of efficiently absorbing and storing compression heat and stably providing a heat source for the energy release stage, thereby ensuring the continuous stability of air heating and ORC cycle, and improving the reliability and scenario adaptability of the heat storage unit.

[0091] ORC pump 24 pressurizes the working fluid of the first circulation subsystem to above 10MPa. By increasing the saturation temperature of the working fluid through high pressure, it enables the working fluid to fully absorb low-grade heat energy and compression waste heat in the ORC first evaporator 27 and ORC second evaporator 25, forming high-temperature and high-pressure superheated steam. This significantly enhances the expansion and work capacity of the working fluid in the ORC expander 26, increasing the power generation per unit of working fluid. At the same time, the high pressure also ensures the flow stability of the working fluid during the circulation process, avoiding insufficient heat exchange caused by insufficient pressure, and further optimizing the energy conversion efficiency of the first circulation subsystem.

[0092] Furthermore, during the energy storage phase, the medium-grade cold energy fluid formed after the LNG releases high-grade cold energy enters ORC condenser 40 to provide cooling for the working fluid of the second cycle subsystem.

[0093] The working fluid of the second circulation subsystem absorbs heat and evaporates in the ORC evaporator 42, driving the ORC expander 39 to generate electricity. After doing work, the working fluid enters the ORC condenser 40, releases waste heat to the medium-grade cold energy fluid and condenses into a liquid state. The condensed working fluid is pressurized by the ORC pump 41 and returns to the ORC evaporator 42 to complete the cycle. The medium-grade cold energy fluid absorbs waste heat and transforms into a low-grade cold energy fluid, which is used for air precooling in the precooler 1.

[0094] Specifically, during the energy storage phase, the medium-grade cold energy fluid formed after the LNG releases high-grade cold energy is directed into ORC condenser 2 40. ORC condenser 2 40 serves as the core heat exchange carrier of the second cycle subsystem. By constructing an efficient heat exchange space between the working fluid and the medium-grade cold energy fluid, it allows the circulating working fluid to fully absorb cold energy and evaporate from liquid to high-pressure steam, thereby providing a working fluid capable of performing work for the subsequent power generation process. After the working fluid of the second cycle subsystem completes evaporation by absorbing heat in ORC evaporator 42, it drives ORC expander 2 39 to operate in the form of high-pressure steam. ORC expander 2 39 converts the thermal energy of the working fluid into the mechanical energy of the impeller rotation, and then further into electrical energy, thereby efficiently recovering the medium-grade cold energy of LNG and realizing the cascade utilization of energy, thus avoiding energy waste caused by the direct emission of medium-grade cold energy.

[0095] After performing work, the working fluid exhaust gas, with its energy decayed, enters ORC condenser 2, 40. ORC condenser 2, 40 establishes a secondary heat exchange channel between the working fluid and the medium-grade cold energy fluid, allowing the working fluid exhaust gas to release residual waste heat and condense back to a liquid state. This creates the necessary conditions for the recycling of the working fluid. Simultaneously, the medium-grade cold energy fluid absorbs the waste heat from the working fluid exhaust gas, further increasing its temperature and transforming into a low-grade cold energy fluid, achieving synergistic recovery of waste heat and cold energy. The condensed liquid working fluid is then pressurized by ORC pump 2, 41. ORC pump 2, 41... As a circulating power source, it precisely pushes the liquid working fluid back to the ORC evaporator 42 to re-participate in heat exchange, thereby forming a closed loop, reducing working fluid loss and lowering system operating costs. The low-grade cold energy fluid formed after absorbing waste heat is introduced into the precooler 1, which uses residual cold energy to assist in precooling the ambient air, thereby reducing the inlet air temperature of the compressor 2, reducing energy consumption during compression, and realizing the full-chain recovery and utilization of cold energy from high grade to low grade, maximizing the overall energy utilization rate of the system.

[0096] Furthermore, during the energy release phase, the vaporized air flows through ORC condenser-23 as a cold source to cool the working fluid of the first cycle subsystem.

[0097] The working fluid of the first cycle subsystem is cooled by ORC condenser 23 and pressurized by ORC pump 24, and then flows through ORC first evaporator 27 and ORC second evaporator 25 in sequence to absorb heat.

[0098] The heat source for the first ORC evaporator 27 is room temperature water, and the heat source for the second ORC evaporator 25 is the residual compression heat stored in the high-temperature tank 35. After absorbing heat, the working fluid forms superheated steam, which drives the ORC expander 26 to generate electricity. The working fluid that has done work returns to the ORC condenser 23 to complete the cycle.

[0099] Specifically, during the energy release stage, the vaporized air carries cold energy as a cold source and flows directionally through ORC condenser 23. ORC condenser 23 constructs a high-efficiency heat exchange chamber between the air and the working fluid of the first circulation subsystem, which enables the working fluid to fully absorb cold energy and quickly condense into a liquid state, thereby laying the foundation for subsequent pressurization and heat exchange of the working fluid, and at the same time realizing the initial recovery and utilization of the cold energy of the vaporized air.

[0100] After the working fluid of the first circulation subsystem is cooled to a liquid state by ORC condenser 23, it is powered by ORC pump 24. ORC pump 24 increases the pressure of the liquid working fluid to meet the heat exchange requirements of the evaporator through precise pressurization, which ensures that the working fluid can fully absorb heat and complete the state transformation, thereby storing energy for the subsequent power generation process. The pressurized liquid working fluid flows through ORC first evaporator 27 and ORC second evaporator 25 in sequence to absorb heat in stages. ORC first evaporator 27 uses room temperature water as a heat source. By building a heat exchange channel between low-grade heat energy and the working fluid, it plays a role in recovering low-grade heat energy of room temperature water and initially increasing the temperature of the working fluid, thereby expanding the energy recovery range of the system and avoiding the waste of low-grade heat energy.

[0101] The ORC second evaporator 25 is connected to the residual compression heat stored in the high-temperature tank 35 of the heat storage unit. Through efficient transfer of high-heat energy, it further heats the working fluid to a superheated steam state, significantly increasing the enthalpy and work capacity of the working fluid, thereby maximizing the utilization value of the residual compression heat. After absorbing heat in the two-stage evaporators, the working fluid drives the ORC expander 26 in the form of high-temperature and high-pressure superheated steam. The ORC expander 26 converts the thermal energy of the working fluid into mechanical kinetic energy, and then further into electrical energy, playing a role in efficiently recovering the system's waste heat and realizing the secondary utilization of energy, thereby significantly improving the energy output efficiency of the entire energy release stage. The working fluid exhaust steam, which has degraded in energy after doing work, returns to the ORC condenser 23 for cooling and condensation again, forming a closed loop. This ensures the continuous and stable operation of the first cycle subsystem and reduces working fluid loss, ultimately achieving the synergistic recovery and utilization of cold energy, low-grade heat energy, and residual compression heat, comprehensively improving the overall energy conversion efficiency of the system.

[0102] Furthermore, the LNG output from the LNG receiving terminal 36 has an initial temperature of -162°C, and the booster pump 37 pressurizes it to 7MPa; the ORC first evaporator 27 absorbs the cold energy and can then provide cold energy to the outside.

[0103] Specifically, the initial temperature of the LNG output from LNG receiving terminal 36 is set at -162℃. This extremely low temperature is the core carrier of the high-grade cold energy of LNG. By maintaining this initial low temperature, it ensures the grade of cold energy and provides sufficient low-temperature potential energy for air liquefaction. This, in turn, ensures that cold boxes 1-8 and 2-12 can quickly reduce the temperature of the high-pressure air to meet the low-temperature requirements of air liquefaction. The booster pump 37 specifically boosts the LNG from atmospheric pressure to 7MPa. Through precise pressurization, it adapts to the system's heat exchange pressure conditions and prevents the LNG from vaporizing too quickly due to insufficient pressure during heat exchange, thereby ensuring a stable LNG supply. The continuous release of high-grade cold energy in the flow state enhances cold energy transfer efficiency and heat exchange stability. While providing cooling for the working fluid in the first cycle subsystem, the ORC first evaporator 27 can also output cold energy by absorbing the cold energy carried by the vaporized air. This expands the system's energy supply dimensions and meets external cooling load demands, such as in industrial refrigeration and cold chain storage scenarios. It breaks through the limitations of single power generation, realizes the coordinated supply of multiple energy sources including cold, electricity, and gas, improves the system's comprehensive utilization value and market adaptability, and fully recovers the residual cold energy of the vaporized air to avoid idle and wasted cold energy, further optimizing the system's energy utilization efficiency.

[0104] Example 2

[0105] A method for reusable liquid air energy storage for combined cooling and power (CCHP) equipment includes the following steps:

[0106] S1. Ambient air is compressed in multiple stages by the compression unit, and the heat of compression generated is recovered and stored by the heat storage unit. At the same time, the high-grade cold energy of liquefied natural gas (LNG) is introduced through the cold box 8 to cool the compressed high-pressure air to assist its liquefaction. The generated liquid air is stored in the storage tank 18. After the LNG releases the high-grade cold energy, the high-grade cold energy is used to drive the second power generation cycle of the organic Rankine cycle unit. After power generation, the LNG is converted into low-grade cold energy and selectively introduced into the precooler 1 to precool the ambient air according to the air temperature at the inlet of the compression unit.

[0107] S2. The stored liquid air is pressurized and vaporized by the cryogenic pump 19. The cold energy released during the vaporization process is recovered and stored by the cold storage unit. The vaporized air serves as a cold source and enters the organic Rankine cycle unit to drive its first power generation cycle. Subsequently, the air passes through the interstage heater 29 and the interstage common heat exchanger 5 and interstage common heat exchanger 3 with reverse flow paths. It is heated step by step by the compression heat stored in the heat storage unit and finally introduced into the first expander 31, the second expander 32, and the third expander 33 of the expansion unit to expand step by step and generate electricity.

[0108] Specifically, ambient air is compressed in multiple stages by the compression unit, and the resulting heat of compression is recovered and stored by the heat storage unit. At the same time, the high-grade cold energy of liquefied natural gas (LNG) is introduced through the cold box 8 to cool the compressed high-pressure air to assist its liquefaction. The generated liquid air is stored in the storage tank 18. After releasing the high-grade cold energy, the high-grade cold energy is used to drive the second power generation cycle of the organic Rankine cycle unit. After power generation, the LNG is converted into low-grade cold energy and selectively introduced into the precooler 1 to precool the ambient air according to the inlet air temperature of the compression unit.

[0109] Pre-cooler 1 initially cools the ambient air, reducing the initial compression load and thus decreasing subsequent compression power consumption. Compressors 2, 4, and 6 progressively increase the air pressure to the required level for liquefaction, creating the necessary pressure conditions. Interstage heat exchangers 3 and 5, along with interstage cooler 7, switch to cooling mode to recover compression heat and transfer it to the high-temperature tank 35, storing heat energy for the energy release phase. Pump 37 pressurizes the LNG from the LNG receiving station 36 to the appropriate pressure, stabilizing the cold energy release rate and ensuring the heat exchange efficiency of cold box 8. Cold box 8 uses high-grade LNG to cool the high-pressure air, and with the cold storage medium assisted by cooling in cold box 12 via heat exchanger channel 15, rapidly reducing the air temperature and increasing the liquefaction rate. Cryogenic expander 16 expands the cooled high-pressure air, reducing its temperature and pressure, thus promoting liquefaction. The system utilizes the following methods to improve liquefaction efficiency: Liquid air is separated from unliquefied cold air via gas-liquid separator 17; the unliquefied cold air is returned to the cold box via heat exchanger second channel 14 for reuse, thus recovering cold energy; liquid air is sealed and stored in storage tank 18, serving as an energy storage medium, thereby achieving energy storage across time periods; medium-grade cold energy fluid from LNG is received by ORC condenser 40, providing cooling for the working fluid in the second cycle subsystem and promoting its condensation; combined with ORC evaporator 42, it absorbs heat to evaporate the working fluid, thus providing power for ORC expander 39 to generate electricity; waste heat from the working fluid vapor is released by ORC condenser 40 and absorbed by LNG, achieving working fluid circulation and cold energy cascade transfer, thus forming low-grade cold energy; temperature sensor 38 monitors the inlet temperature of the compression unit, and in conjunction with regulating valve 28, dynamically adjusts the low-grade cold energy flow rate, maintaining a constant inlet temperature and optimizing compression conditions; simultaneously, the vaporized natural gas can be supplied externally.

[0110] The stored liquid air is pressurized and vaporized by the cryogenic pump 19. The cold energy released during the vaporization process is recovered and stored by the cold storage unit. The vaporized air serves as a cold source and enters the organic Rankine cycle unit to drive its first power generation cycle. Subsequently, the air passes through the interstage heater 29 and the interstage common heat exchanger 5 and interstage common heat exchanger 3 with reverse flow paths. It is heated step by step by the compression heat stored in the heat storage unit and finally introduced into the first expander 31, the second expander 32, and the third expander 33 of the expansion unit to expand step by step and generate electricity.

[0111] The cryogenic pump 19 pressurizes the liquid air in the storage tank 18 to meet the pressure requirements for vaporization and expansion, thus laying the foundation for energy release. The evaporator body 20 provides space for the vaporization of liquid air, converting liquid energy into gaseous energy, thereby releasing energy. The cold storage medium in the heat storage tank 22 enters the evaporator body 20 to absorb the vaporized cold energy, then returns to the cold storage tank 21 for storage. Combined with the third channel 15 of the heat exchanger, this recovers and recycles the vaporized cold energy, reducing cold energy waste. The ORC condenser 23 uses the cold energy of the vaporized air to cool the working fluid, ensuring the stable operation of the first cycle subsystem and recovering cold energy to assist in power generation. The ORC first evaporator 27... The ORC second evaporator 25 absorbs residual heat from the high-temperature tank 35, thereby increasing the enthalpy of the working fluid and enhancing the power generation capacity of the ORC expander 26. Through the interstage heater 29 and the interstage common heat exchangers 25 and 3 (which switch to heating mode after reversing the flow path), the air is heated sequentially, steadily increasing its temperature and enthalpy, thus maximizing its expansion potential. Through the first expander 31, second expander 32, and third expander 33, the internal energy of the air is converted into electrical energy in stages, reducing energy loss and achieving efficient energy output. Ultimately, this achieves a comprehensive effect of equipment reuse, combined cooling, electricity, and gas power supply, and improved system efficiency.

[0112] Finally, it should be noted that the above description is only a preferred embodiment 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 foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A device multiplexed liquid air energy storage system for cold co-generation, characterized in that, The system comprises a compression unit, a cold storage unit, an organic Rankine cycle unit, a heat storage unit and an expansion unit, and the system operation comprises an energy storage stage and an energy release stage; In the energy storage stage, ambient air is first introduced into the precooler (1), and after being precooled, sequentially flows through the compressor one (2), the inter-stage common heat exchanger one (3), the compressor two (4), the inter-stage common heat exchanger two (5), the compressor three (6) and the inter-stage cooler (7) to complete multi-stage compression; The compressed high-pressure air enters the cold box one (8) through the cold box second passage (10), exchanges heat with the high-grade cold energy of LNG, and then enters the cold box two (12) through the cold box third passage (11) for further cooling, is expanded by the low-temperature expander (16) to reduce temperature and pressure, and is separated into liquid air and unliquefied cold air in the gas-liquid separator (17); The unliquefied cold air returns to the cold box one (8) through the hot charging exchanger second passage (14) and the cold box third passage (11) to release cold energy, and after releasing the cold energy, is mixed with the supplemented ambient air and returned to the inlet of the precooler (1); In the energy release stage, the liquid air stored in the liquid storage tank (18) is pressurized by the low-temperature pump (19) and then enters the evaporator body (20) to be gasified, and the cold energy released by the gasification is recovered and stored by the cold storage unit; The gasified air enters the organic Rankine cycle unit as a cold source to drive the organic Rankine cycle unit to complete a power generation cycle; The air after power generation sequentially flows through the inter-stage heater (29), the inter-stage common heat exchanger two (5) and the inter-stage common heat exchanger one (3), is gradually heated by the compression heat stored by the heat storage unit, and then sequentially enters the first expander (31), the second expander (32) and the third expander (33) of the expansion unit to be gradually expanded to generate power.

2. The device multiplexed liquid air energy storage system for cold CCHP of claim 1, wherein, The compression unit comprises a precooler (1), a compressor one (2), a compressor two (4), a compressor three (6), an inter-stage common heat exchanger one (3), an inter-stage common heat exchanger two (5), an inter-stage cooler (7), a low-temperature expander (16), a gas-liquid separator (17), a cold box first passage (9), a cold box second passage (10), a cold box third passage (11), a hot charging exchanger first passage (13) and a hot charging exchanger second passage (14); In the energy storage stage, ambient air first enters the precooler (1), and after being precooled, sequentially flows through the compressor one (2), the inter-stage common heat exchanger one (3), the compressor two (4), the inter-stage common heat exchanger two (5), the compressor three (6) and the inter-stage cooler (7) to complete multi-stage compression; The compressed high-pressure air enters the cold box one (8) through the cold box second passage (10), exchanges heat with the high-grade cold energy of LNG, and then enters the cold box two (12) through the cold box third passage (11) for further cooling, is expanded by the low-temperature expander (16) to reduce temperature and pressure, and is separated into liquid air and unliquefied cold air in the gas-liquid separator (17); The unliquefied cold air returns to the cold box one (8) through the hot charging exchanger second passage (14) and the cold box third passage (11) to release cold energy, and after releasing the cold energy, is mixed with the supplemented ambient air and returned to the inlet of the precooler (1); The inter-stage common heat exchanger one (3), the inter-stage common heat exchanger two (5) and the inter-stage cooler (7) transmit the compression heat to the high-temperature tank (35) of the heat storage unit, and the heat-exchanged storage heat medium is stored in the low-temperature tank (34).

3. The device multiplexed liquid air energy storage system for cold CCHP of claim 1, wherein, The cold storage unit comprises a cold storage tank (21), a heat storage tank (22), an evaporator body (20) and a third passage (15) of the heat addition exchanger; In the energy storage stage, the non-liquefied cold air separated by the gas-liquid separator (17) passes through the second passage (14) of the heat addition exchanger, the cold storage medium in the cold storage tank (21) passes through the third passage (15) of the heat addition exchanger and enters the cold box two (12), releases cold energy to assist air liquefaction, and the cold release cold storage medium is stored in the heat storage tank (22); In the energy release stage, the cold storage medium in the heat storage tank (22) enters the evaporator body (20), heats and vaporizes the liquid air, and is returned to the heat storage tank (22) for storage.

4. The device multiplexed liquid air energy storage system for cold CCHP of claim 2, wherein, The inter-stage common heat exchanger one (3) and the inter-stage common heat exchanger two (5) are reversible heat exchanger groups; In the energy storage stage, the flow path is controlled by the regulating valve (28), the inter-stage common heat exchanger one (3) and the inter-stage common heat exchanger two (5) are used as heat exchangers for performing the inter-stage cooling function, cool the compressed air at the outlets of the compressor one (2) and the compressor two (4) respectively, and cooperate with the independently arranged inter-stage cooler (7) to jointly transmit the recovered compression heat to the high-temperature tank (35); In the energy release stage, the flow path is reversely switched by the regulating valve (28), the inter-stage common heat exchanger one (3) and the inter-stage common heat exchanger two (5) are used as heat exchangers for performing the inter-stage heating function, and the heat stored in the high-temperature tank (35) is used to heat the air before expansion.

5. The device multiplexed liquid air energy storage system for cold CCHP of claim 2, wherein, The temperature sensor (38) is arranged at the inlet of the compressor one (2); In the energy storage stage, the temperature sensor (38) is used for detecting the inlet air temperature, when the detected temperature is higher than the set temperature, the low-grade cold energy fluid from the organic Rankine cycle unit is introduced into the pre-cooler (1) to pre-cool the air, the flow of the low-grade cold energy fluid is dynamically adjusted by the regulating valve (28) to maintain the constant temperature of the inlet air of the compressor one (2), and the vaporized natural gas after pre-cooling is supplied externally.

6. The device multiplexed liquid air energy storage system for cold- CCHP of claim 1, wherein, The organic Rankine cycle unit comprises a first circulation subsystem and a second circulation subsystem; The second circulation subsystem comprises an ORC evaporator (42), an ORC expander two (39), an ORC condenser two (40) and an ORC pump two (41), and is operated in the energy storage stage; The first circulation subsystem comprises an ORC condenser one (23), an ORC pump one (24), an ORC first evaporator (27), an ORC second evaporator (25) and an ORC expander one (26), and is operated in the energy release stage; The circulating working medium of the organic Rankine cycle unit is propane or R134a, the cold storage medium of the cold storage unit is propane or nitrogen, the storage heat medium of the heat storage unit is pressurized water, heat-conducting oil or molten salt, and the ORC pump one (24) pressurizes the working medium of the first circulation subsystem to 10 MPa or above.

7. The device multiplexed liquid air energy storage system for cold CCHP of claim 6, wherein, In the energy storage stage, the medium-grade cold energy fluid formed after the LNG releases high-grade cold energy enters the ORC condenser two (40) to provide cold energy for the working medium of the second circulation subsystem. The working medium of the second circulation subsystem is evaporated by heat absorption of the ORC evaporator (42), drives the ORC expander two (39) to generate electricity; the working medium after work enters the ORC condenser two (40), releases waste heat to the medium-grade cold energy fluid and condenses into liquid; the condensed working medium is pressurized by the ORC pump two (41) and returns to the ORC evaporator (42) to complete the cycle; the medium-grade cold energy fluid is converted into low-grade cold energy fluid after absorbing waste heat, and is used for air precooling of the precooler (1).

8. The device multiplexed liquid air energy storage system for cold CCHP of claim 6, wherein, In the energy release stage, the gasified air flows through the ORC condenser one (23) as a cold source to cool the working medium of the first circulation subsystem; The working medium of the first circulation subsystem is cooled by the ORC condenser one (23), pressurized by the ORC pump one (24), and sequentially flows through the ORC first evaporator (27) and the ORC second evaporator (25) to absorb heat; The heat source of the ORC first evaporator (27) is normal temperature water, and the heat source of the ORC second evaporator (25) is the residual compression heat stored in the high-temperature tank (35); the working medium is heated to form superheated steam, drives the ORC expander one (26) to generate electricity, and the working medium after work returns to the ORC condenser one (23) to complete the cycle.

9. The device multiplexed liquid air energy storage system for cold- CCHP of claim 5, wherein, The initial temperature of the LNG output by the LNG receiving station (36) is-162℃, and the boost pump (37) increases the pressure to 7MPa; the ORC first evaporator (27) can provide cold energy after absorbing cold.

10. A method for device multiplexed liquid air energy storage for cold co-generation, characterized in that, The device multiplexed liquid air energy storage system for cold electricity supply according to any one of claims 1-9, comprising the following steps: S1, the ambient air is compressed by a plurality of stages of the compression unit, and the compression heat generated is recovered and stored by the heat storage unit; at the same time, the high-grade cold energy of liquefied natural gas LNG is introduced through the cold box one (8) to cool the compressed high-pressure air to assist liquefaction, and the generated liquid air is stored in the liquid storage tank (18); after releasing the high-grade cold energy, the LNG is converted into low-grade cold energy, and according to the inlet air temperature of the compression unit, the LNG is selectively introduced into the precooler (1) to precool the ambient air; S2, the stored liquid air is pressurized and gasified by the low-temperature pump (19), and the cold energy released in the gasification process is recovered and stored by the cold storage unit; the gasified air enters the organic Rankine cycle unit as a cold source and drives the first power generation cycle thereof; then, the air is gradually heated by the inter-stage heater (29), the inter-stage common heat exchanger two (5) and the inter-stage common heat exchanger one (3) with reversely switched flow paths, and the compression heat stored by the heat storage unit, and finally introduced into the first expander (31), the second expander (32) and the third expander (33) of the expansion unit to gradually expand and generate electricity.

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