Cold energy recovery system of liquefied air energy storage system and control method

Abstract

The invention relates to a cold energy recovery system of a liquefied air energy storage system and a control method. The cold energy recovery system of the liquefied air energy storage system comprises an air processing mechanism, a heat exchange mechanism, a storage mechanism and an expansion power generation mechanism. A first gas output end of the air processing mechanism is connected with a first gas input end of the heat exchange mechanism, a gas-liquid output end of the heat exchange mechanism is connected with a gas-liquid input end of the storage mechanism, and a gas output end of the storage mechanism is connected with a second gas input end of the heat exchange mechanism. The liquid output end of the storage mechanism is connected with the liquid input end of the heat exchange mechanism, the third gas output end of the heat exchange mechanism is connected with the gas input end of the expansion power generation mechanism, liquid air is stored through gas-liquid separation, and the cooling capacity of the gaseous part is recycled and introduced into the heat exchange process again. And the air is vaporized into air to be subjected to power generation through heat exchange. Multiple times of energy loss caused by indirect transmission of cold energy is avoided, and the utilization efficiency of cold energy is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of liquefied air energy storage, and in particular to a cold recovery system and a control method for a liquefied air energy storage system. Background Art

[0002] At present, as a major energy producer and consumer, my country's energy structure optimization and resource utilization efficiency improvement are key means to solve energy problems. As a core technology for achieving energy structure adjustment, large-scale renewable energy development and energy security improvement, electric energy storage can achieve efficient energy utilization by converting excess electric energy into other forms of storage during low electricity consumption, and then releasing it as electric energy during peak electricity consumption. Liquid air energy storage technology is derived from compressed air energy storage technology. Through thermodynamic processes such as air compression, liquefaction, vaporization and expansion, it completes the cyclic conversion of electric energy and thermal energy, and can effectively realize the "valley electricity peak use" of electricity. At present, as a new energy storage method, liquid air energy storage still has bottlenecks in energy utilization. Existing technologies usually store the cold energy generated during the power generation process of the expander in media such as gravel, propane or methanol, and then indirectly transfer it to the air for cooling during the air compression and liquefaction process. This method causes a large loss of cold energy due to multiple heat transfer processes, and the heat transfer temperature is high, so it can only act on high-temperature air, resulting in low utilization efficiency of cold energy and failure to fully reduce liquefaction energy consumption. How to improve the liquefaction efficiency and the overall energy utilization of the system through direct and efficient cold transfer has become a key issue that needs to be urgently addressed in liquefied air energy storage technology. Summary of the invention

[0003] In order to solve the problems of low cold transfer efficiency, serious energy loss and insufficient cold energy utilization in the existing liquefied air energy storage technology, the present application provides a cold recovery system and control method for a liquefied air energy storage system.

[0004] A cold energy recovery system for a liquefied air energy storage system, the cold energy recovery system for a liquefied air energy storage system comprising an air processing mechanism, a heat exchange mechanism, an expansion refrigeration mechanism, a storage mechanism and an expansion power generation mechanism; The gas input end of the air processing mechanism is used to receive air, and the air processing mechanism is used to process air to form processed air. The first gas output end of the air processing mechanism is connected to the first gas input end of the heat exchange mechanism, the gas-liquid output end of the heat exchange mechanism is connected to the gas-liquid input end of the storage mechanism, the gas output end of the storage mechanism is connected to the second gas input end of the heat exchange mechanism, the second gas output end of the air processing mechanism is connected to the compression end of the expansion refrigeration mechanism, the gas input end of the expansion refrigeration mechanism is connected to the first gas output end of the heat exchange mechanism, the pipeline between the gas-liquid output end of the heat exchange mechanism and the gas-liquid input end of the storage mechanism is connected to the gas output end of the expansion refrigeration mechanism, the second gas output end of the heat exchange mechanism is connected to the atmosphere, or is connected to the gas input end of the air processing mechanism, the liquid output end of the storage mechanism is connected to the liquid input end of the heat exchange mechanism, the third gas output end of the heat exchange mechanism is connected to the gas input end of the expansion power generation mechanism, and the gas output end of the expansion power generation mechanism is connected to the atmosphere, or is connected to the gas input end of the air processing mechanism; When the power consumption is low, the processed air is heat-exchanged into a gas-liquid two-phase mixture after entering the heat exchange mechanism, the liquid air in the gas-liquid two-phase mixture is stored in the storage mechanism, and the circulating air in the gas-liquid two-phase mixture is mixed with the refrigeration air output from the gas output end of the expansion refrigeration mechanism, and then heat-exchanged with the processed air; When electricity consumption is at its peak, the storage mechanism outputs liquid air to the heat exchange mechanism for heat exchange to vaporize into air to be used for power generation. The expansion power generation mechanism includes an expansion component and a power generation component. The air to be used for power generation enters the expansion component to expand and perform work to drive the power generation component to generate electricity.

[0005] By adopting the above technical solution, the present application closely combines the processing and circulation of air with the recovery of cold energy. When the power consumption is low, the air processing mechanism receives the atmospheric air and pre-processes it. The processed air is sent to the heat exchange mechanism, and is cooled to a gas-liquid two-phase mixture state through heat exchange, wherein the liquid part is stored in the storage mechanism for subsequent power generation needs, while the gaseous part (i.e., circulating air) continues to mix with the refrigerated air generated by the expansion refrigeration mechanism and then exchanges heat with the processed air. This circulation path after gas-liquid separation ensures the maximum utilization of cold energy, which not only stores the liquid air through gas-liquid separation, but also recovers the cold energy of the gaseous part and reintroduces it into the heat exchange process, reducing the loss of cold energy; when the power consumption is high, the system takes out the liquid air from the storage mechanism and sends it back to the heat exchange mechanism, and vaporizes it into air to be used for power generation through heat exchange. Liquid air absorbs a lot of heat during the vaporization process, and this part of heat comes from the heat exchange mechanism of the system, which means that the cold energy stored during the low power consumption can be fully recovered and converted into refrigeration capacity. In addition, this cycle avoids multiple energy losses caused by indirect transfer of cold in traditional technologies. Cold is directly and efficiently transferred within the system, which improves the utilization efficiency of cold energy. In the power generation stage, the expansion components in the expansion power generation mechanism convert the internal energy of the air to be generated into mechanical energy through the expansion process of the air to be generated, driving the power generation components to generate electricity. During the expansion process, the air temperature decreases and generates cold, which can be mixed with the circulating air in the system to further cool the processed air, thereby further improving the system's cold recovery efficiency and recycling rate.

[0006] Preferably, the air processing mechanism includes an air filter, an air compressor, a first cooler, a first processing control valve and a second processing control valve, one end of the first processing control valve is connected to the air filter, and the other end is connected to one end of the air compressor, the other end of the air compressor is connected to one end of the first cooler, the other end of the first cooler is connected to one end of the second processing control valve, and the other end of the second processing control valve is connected to the first gas input end of the heat exchange mechanism.

[0007] By adopting the above technical solutions, the air can be effectively filtered, compressed and cooled, thereby removing impurities in the air and reducing the air temperature, creating good process conditions for subsequent air liquefaction and heat exchange, avoiding the adverse effects of impurities and high temperature on the operation of equipment and systems, and improving the efficiency and stability of air processing.

[0008] Preferably, the air processing mechanism also includes a gas-liquid separator, a molecular sieve adsorber, a spherical tank and a third processing control valve, one end of the gas-liquid separator is connected to the other end of the second processing control valve, the other end of the gas-liquid separator is connected to one end of the molecular sieve adsorber, the other end of the molecular sieve adsorber is connected to one end of the spherical tank, the other end of the spherical tank is connected to one end of the third processing control valve, and the other end of the third processing control valve is connected to the first gas input end of the heat exchange mechanism.

[0009] By adopting the above technical solution, the free water in the air can be removed by using a gas-liquid separator, and the water, carbon dioxide and organic hydrocarbon impurities can be further removed by a molecular sieve adsorber to prevent impurities from freezing and clogging pipes and devices under low temperature conditions. At the same time, the storage pressure and flow of the air can be stabilized by a spherical tank to ensure the purity of the air before it enters the heat exchange mechanism and the process requirements, thereby improving the safety and liquefaction efficiency of the system.

[0010] Preferably, the heat exchange mechanism includes a first plate-fin heat exchanger, a second plate-fin heat exchanger and a heat exchange throttle valve, the first heat medium input end of the first plate-fin heat exchanger is connected to the first gas output end of the air processing mechanism, the first heat medium output end of the first plate-fin heat exchanger is connected to the first heat medium input end of the second plate-fin heat exchanger, the first heat medium output end of the second plate-fin heat exchanger is connected to one end of the heat exchange throttle valve, and the other end of the heat exchange throttle valve is connected to the gas-liquid input end of the storage mechanism.

[0011] By adopting the above technical scheme, the processed air can be cooled in multiple stages through the first plate-fin heat exchanger and the second plate-fin heat exchanger, and the gas can be depressurized and cooled by using a heat exchange throttle valve, so that the air can quickly form a gas-liquid two-phase mixture during the heat exchange process, thereby effectively reducing the energy consumption of the air liquefaction process and improving the cold capacity utilization rate and liquefaction efficiency.

[0012] Preferably, the expansion refrigeration mechanism comprises a refrigeration expander and a refrigeration throttle valve, and the refrigeration expander comprises a compression end and an expansion end; One end of the compression end is connected to one end of the refrigeration throttle valve, the other end of the refrigeration throttle valve is connected to the second gas output end of the air processing mechanism, the other end of the compression end is connected to the second heat medium input end of the first plate-fin heat exchanger, the second heat medium output end of the first plate-fin heat exchanger is connected to the second heat medium input end of the second plate-fin heat exchanger, and the second heat medium output end of the second plate-fin heat exchanger is connected to one end of the heat exchange throttle valve; One end of the expansion end is connected to the second heat medium input end of the second plate-fin heat exchanger, the first cold medium input end of the second plate-fin heat exchanger is connected to the gas output end of the storage mechanism, the first cold medium output end of the second plate-fin heat exchanger is connected to the first cold medium input end of the first plate-fin heat exchanger, the first cold medium output end of the first plate-fin heat exchanger is connected to the atmosphere, or is connected to the gas input end of the air processing mechanism, and the pipeline between the first cold medium input end of the second plate-fin heat exchanger and the liquid input end of the heat exchange mechanism is connected to the other end of the expansion end.

[0013] By adopting the above technical solution, the air can be circulated and cooled by heat exchange through the compression end and expansion end of the refrigeration expander in combination with a refrigeration throttle valve, and the cold released during the expansion process is transferred to the air or cold medium in the heat exchange mechanism, thereby efficiently recovering the cold and reducing the external refrigeration demand of the system, significantly improving the utilization rate of the cold, and reducing the energy consumption of liquefied air.

[0014] Preferably, a second cooler is connected between the other end of the compression end and the second heat medium input end of the first plate-fin heat exchanger.

[0015] By adopting the above technical solution, the air temperature can be further reduced by combining the compression end of the refrigeration expander with the second cooler, thereby improving the initial cooling effect of air liquefaction on the basis of compression cooling, providing a lower initial temperature for multi-stage heat exchange in the plate-fin heat exchanger, optimizing the cold transfer efficiency, and further reducing the energy consumption of air liquefaction.

[0016] Preferably, the storage mechanism includes a storage control valve, a liquid storage tank and a liquid air pump, the gas-liquid input end of the liquid storage tank is connected to the other end of the heat exchange throttle valve, the gas output end of the liquid storage tank is connected to one end of the storage control valve, the other end of the storage control valve is connected to the first cold medium input end of the second plate-fin heat exchanger, the liquid output end of the liquid storage tank is connected to one end of the liquid air pump, the other end of the liquid air pump is connected to the second cold medium input end of the second plate-fin heat exchanger, the second cold medium output end of the second plate-fin heat exchanger is connected to the second cold medium input end of the first plate-fin heat exchanger, and the second cold medium output end of the first plate-fin heat exchanger is connected to the gas input end of the expansion power generation mechanism.

[0017] By adopting the above technical solution, liquid air can be stably stored through the liquid storage tank in the storage mechanism, and the liquid air can be output to the heat exchange mechanism in combination with the liquid air pump to achieve stable transportation and reuse of the liquid air. At the same time, the discharge flow of the gaseous air in the storage tank is adjusted by the storage control valve to ensure the stability of the liquid level in the storage tank, thereby optimizing the liquefied air storage and transportation process and ensuring the continuity and efficiency of the system operation.

[0018] Preferably, the power generation component includes a first generator and a second generator, and the expansion component includes a first power generation expander for driving the first generator to generate electricity, and a second power generation expander for driving the second generator to generate electricity, one end of the first power generation expander is connected to the second cold medium output end of the first plate-fin heat exchanger, the other end of the first power generation expander is connected to the third cold medium input end of the first plate-fin heat exchanger, the third cold medium output end of the first plate-fin heat exchanger is connected to one end of the second power generation expander, and the other end of the second power generation expander is connected to the atmosphere, or is connected to the gas input end of the air processing mechanism.

[0019] By adopting the above technical solution, the expansion component can drive the operation of the power generation component, and multi-stage expansion power generation can be achieved through the coordinated action of the first power generation expander and the second power generation expander. The internal energy of the vaporized liquid air is converted into mechanical energy to drive the generator to generate electricity, thereby improving the energy utilization efficiency of the expansion process and improving the overall power generation efficiency of the energy storage system.

[0020] Preferably, a first heater is provided between one end of the first power generation expander and the second cold medium output end of the first plate-fin heat exchanger, and a second heater is provided between the third cold medium output end of the first plate-fin heat exchanger and one end of the second power generation expander.

[0021] By adopting the above technical solution, a first heater can be set between the first power generation expander and the plate-fin heat exchanger, and a second heater can be set between the second power generation expander and the plate-fin heat exchanger, so as to heat the expanded air, increase the initial temperature of the air before expansion, enhance the working capacity of the expander, and further improve the expansion power generation efficiency.

[0022] A control method for a cold recovery system of a liquefied air energy storage system is applied to a cold recovery system of a liquefied air energy storage system, and the control method comprises: Determine a current power consumption state, wherein the current power consumption state includes at least a power consumption valley and a power consumption peak; If the current power consumption state is a low power consumption state, the liquid level data of the storage mechanism is obtained to determine whether the liquid level data is less than a predetermined preset liquid level threshold value; if it is not less than the predetermined preset liquid level threshold value, the determination is continued; if it is less than the predetermined preset liquid level threshold value, the expansion power generation mechanism is turned off, and the air processing mechanism, the expansion refrigeration mechanism, the heat exchange mechanism and the storage mechanism are turned on, so that the storage mechanism stores liquid air until the liquid level data is greater than or equal to the predetermined preset liquid level threshold value; If the current power consumption state is at a peak, the expansion refrigeration mechanism is turned off, and the air processing mechanism, the expansion power generation mechanism, the heat exchange mechanism and the storage mechanism are turned on to enable the expansion power generation mechanism to generate electricity.

[0023] By adopting the above technical scheme, the storage state of the liquid air during the low electricity consumption period can be judged in real time through the liquid level data of the storage mechanism, the operation state of the air processing mechanism, the expansion refrigeration mechanism and the storage mechanism can be flexibly controlled, and the liquefaction storage process can be started in time when the liquid level is insufficient to ensure the stability of the reserve of liquid air in the storage mechanism, thereby ensuring the power generation demand during the subsequent peak electricity consumption period; the expansion refrigeration mechanism can be shut down in real time according to the power demand during the peak electricity consumption period, and the air processing mechanism, the expansion power generation mechanism and the heat exchange mechanism can be started at the same time to efficiently convert the liquid air in the storage mechanism into expanded power generation air, and the generator can be driven to generate electricity through expansion work, thereby ensuring the efficiency and stability of the power generation process, thereby meeting the power supply demand during the peak electricity consumption period and improving the responsiveness and adaptability of the system operation.

[0024] In summary, the present application includes at least one of the following beneficial technical effects: 1. The present application closely combines the processing and circulation of air with cold recovery. When electricity consumption is low, the air processing mechanism receives atmospheric air and pre-processes it. The processed air is sent to the heat exchange mechanism and cooled to a gas-liquid two-phase mixture state through heat exchange, wherein the liquid portion is stored in the storage mechanism for subsequent power generation needs, while the gaseous portion (i.e., circulating air) continues to mix with the refrigerated air generated by the expansion refrigeration mechanism and then exchanges heat with the processed air. This circulation path after gas-liquid separation ensures the maximum utilization of cold energy, storing liquid air through gas-liquid separation, and recovering the cold energy of the gaseous portion and reintroducing it into the heat exchange process, reducing the loss of cold energy; 2. During peak electricity consumption, the system takes out liquid air from the storage mechanism and sends it back to the heat exchange mechanism, where it is vaporized into air to be used for power generation through heat exchange. Liquid air absorbs a large amount of heat during the vaporization process, and this part of the heat comes from the system's heat exchange mechanism, which means that the cold stored during low electricity consumption can be fully recovered and converted into refrigeration capacity. In addition, this cycle avoids multiple energy losses caused by indirect transfer of cold in traditional technologies. The cold is directly and efficiently transferred within the system, which improves the utilization efficiency of cold energy. During the power generation stage, the expansion components in the expansion power generation mechanism convert the internal energy of the air to be used for power generation into mechanical energy through the expansion process, driving the power generation components to generate electricity. During the expansion process, the air temperature decreases to generate cold, which can be mixed with the circulating air in the system to further cool the processed air, thereby further improving the system's cold recovery efficiency and recycling rate; 3. Compared with the performance of the pilot plant of traditional liquefied air energy storage technology, this system has achieved a qualitative leap in efficiency. According to data released by Highview Power, the energy storage cycle efficiency of its pilot plant was only 8%, while this system achieved an energy storage cycle efficiency of up to 40.8% without coupling any additional refrigeration resources through direct cold heat exchange, efficient cold energy recovery and closed-loop circulation design. This significant improvement shows that the system has overcome the problems of cold loss and inefficiency in traditional technologies by optimizing the cold transfer path, improving the energy recovery mechanism and improving the heat exchange efficiency, providing an efficient and energy-saving technical solution for the commercial application of liquefied air energy storage.

[0025] Description of reference numerals: 1. Air processing mechanism; 11. Air filter; 12. Air compressor; 13. First cooler; 14. First processing control valve; 15. Second processing control valve; 16. Gas-liquid separator; 17. Molecular sieve adsorber; 18. Spherical tank; 19. Third processing control valve; 2. Heat exchange mechanism; 21. First plate-fin heat exchanger; 22. Second plate-fin heat exchanger; 23. Heat exchange throttle valve; 3. Expansion refrigeration mechanism; 31. Refrigeration expander; 311. Compression end; 312. Expansion end; 32. Refrigeration throttle valve; 33. Second cooler; 4. Storage mechanism; 41. Storage control valve; 42. Liquid storage tank; 43. Liquid air pump; 5. Expansion power generation mechanism; 51. First generator; 52. Second generator; 53. First power generation expander; 54. Second power generation expander; 55. First heater; 56. Second heater. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a structural implementation block diagram of a cold recovery system of a liquefied air energy storage system in one embodiment of the present application; Figure 2 This is a schematic diagram of the specific structure of a cold recovery system of a liquefied air energy storage system in an embodiment of the present application. Figure 1 ; Figure 3 This is a schematic diagram of the specific structure of a cold recovery system of a liquefied air energy storage system in an embodiment of the present application. Figure 2 ; Figure 4 It is a flow chart for implementing a control method of a cold recovery system of a liquefied air energy storage system in one embodiment of the present application. DETAILED DESCRIPTION

[0027] The present application is further described in detail below in conjunction with the accompanying drawings.

[0028] In one embodiment, if Figure 1As shown, the present application discloses a cold recovery system for a liquefied air energy storage system, a cold recovery system for a liquefied air energy storage system comprises an air processing mechanism 1, a heat exchange mechanism 2, an expansion refrigeration mechanism 3, a storage mechanism 4 and an expansion power generation mechanism 5; The gas input end of the air processing mechanism 1 is used to receive air. The air processing mechanism 1 is used to process air to form processed air. The first gas output end of the air processing mechanism 1 is connected to the first gas input end of the heat exchanging mechanism 2. The gas-liquid output end of the heat exchanging mechanism 2 is connected to the gas-liquid input end of the storage mechanism 4. The gas output end of the storage mechanism 4 is connected to the second gas input end of the heat exchanging mechanism 2. The second gas output end of the air processing mechanism 1 is connected to the compression end of the expansion refrigeration mechanism 3. The gas input end of the expansion refrigeration mechanism 3 is connected to the first gas output end of the heat exchanging mechanism 2. The pipeline between the gas-liquid output end of the heat exchanging mechanism 2 and the gas-liquid input end of the storage mechanism 4 is connected to the gas output end of the expansion refrigeration mechanism 3. The second gas output end of the heat exchanging mechanism 2 is connected to the atmosphere or connected to the gas input end of the air processing mechanism 1. The liquid output end of the storage mechanism 4 is connected to the liquid input end of the heat exchanging mechanism 2. The third gas output end of the heat exchanging mechanism 2 is connected to the gas input end of the expansion power generation mechanism 5. The gas output end of the expansion power generation mechanism 5 is connected to the atmosphere or connected to the gas input end of the air processing mechanism 1. When the electricity consumption is low, the processed air is heat-exchanged into a gas-liquid two-phase mixture after entering the heat exchange mechanism 2, and the liquid air in the gas-liquid two-phase mixture is stored in the storage mechanism 4. The circulating air in the gas-liquid two-phase mixture is mixed with the refrigeration air output from the gas output end of the expansion refrigeration mechanism 3, and then heat-exchanged with the processed air. When electricity consumption is at its peak, the storage mechanism 4 outputs liquid air to the heat exchange mechanism 2 for heat exchange to vaporize into air to be used for power generation. The expansion power generation mechanism 5 includes an expansion component and a power generation component. The air to be used for power generation enters the expansion component to expand and perform work to drive the power generation component to generate electricity.

[0029] In this embodiment, the modules of the cold recovery system of the liquefied air energy storage system realize highly coordinated operation logic through precise port connections. The gas input end of the air processing mechanism 1 is responsible for receiving external air and processing it to form processed air. The processed air enters the first gas input end of the heat exchange mechanism 2 through the first gas output end of the air processing mechanism 1. After the heat exchange mechanism 2 receives the processed air, it cools the air to a gas-liquid two-phase mixture state through its internal heat exchange component, and then transports the liquid part of the gas-liquid mixture to the gas-liquid input end of the storage mechanism 4 through its gas-liquid output end for storage for use during peak electricity consumption. At the same time, the storage mechanism 4 transports the stored gaseous part to the second gas input end of the heat exchange mechanism 2 through its gas output end, so as to achieve further cooling and recycling of the stored gas. In addition, the second gas output end of the air processing mechanism 1 is connected to the compression end of the expansion refrigeration mechanism 3. The expansion refrigeration mechanism 3 outputs the refrigerated air generated by the compression and expansion process inside it from its gas output end, and is connected to the connection between the gas-liquid output end of the heat exchange mechanism 2 and the gas-liquid input end of the storage mechanism 4 through a pipeline, so that the refrigerated air and the circulating air are mixed and then enter the heat exchange mechanism 2 for cold recovery and transmission, further improving the cold utilization efficiency. At the same time, the second gas output end of the heat exchange mechanism 2 can be directly connected to the atmosphere, or connected to the gas input end of the air processing mechanism 1, so as to realize the discharge or circulation recovery of cold air. During the peak period of electricity consumption, the storage mechanism 4 transports the stored liquid air to the liquid input end of the heat exchange mechanism 2 through its liquid output end for vaporization heat exchange, and the vaporized air to be generated is transported to the gas input end of the expansion power generation mechanism 5 through the third gas output end of the heat exchange mechanism 2. In the expansion power generation mechanism 5, the air to be generated enters the expansion component to complete the expansion work, and converts the mechanical energy generated by the expansion into the electrical energy output of the power generation component. The gas output end of the expansion power generation mechanism 5 can be connected to the atmosphere or to the gas input end of the air processing mechanism 1 to complete discharge or recycling. Through the above logic, each module can efficiently complete the processing, cooling, storage and cold recycling of air during low power consumption, and realize the vaporization, expansion and power generation of liquid air during peak power consumption, ensuring that the system can achieve efficient cold utilization and energy conversion under different power load conditions.

[0030] Specifically, the expansion refrigeration mechanism 3 plays a key role in the liquefied air energy storage system, and its necessity is reflected in the efficient generation and recovery of cold, the reduction of energy consumption and the improvement of the overall performance of the system. In the process of air liquefaction, the air needs to be gradually cooled from room temperature to the extremely low temperature required for liquefaction. This process itself has extremely high energy consumption. If the cold is provided by relying solely on traditional cooling methods and heat exchangers, the system energy consumption will increase significantly and cannot meet the economic requirements. The introduction of the expansion refrigeration mechanism 3 realizes efficient refrigeration through the thermodynamic characteristics of the expander, which not only greatly reduces the energy consumption of the system, but also optimizes the utilization efficiency of cold. Specifically, the expansion refrigeration mechanism 3 expands the high-pressure air to a low-pressure state through the combined operation of the compression end and the expansion end. In this process, the temperature of the air is significantly reduced, and a large amount of cold is released. These cold can directly participate in the cooling and heat exchange link in the air liquefaction process, replacing the role of some traditional cooling equipment, thereby effectively reducing the external refrigeration demand. In addition, the expansion refrigeration mechanism 3 forms a tight cold circulation loop with the heat exchange mechanism 2 and the storage mechanism 4. By directly transferring the cold generated during the expansion process to the circulating air or the stored liquid air, not only the cold of the expander is recovered, but also the loss of cold in the multiple transfer processes is avoided, thereby maximizing the utilization rate of cold energy. The expansion refrigeration mechanism 3 can also adjust the initial temperature of the air when it enters the heat exchange mechanism 2, and further reduce the energy consumption required for air liquefaction by providing refrigerated air with a lower temperature, mixing it with the processed hot air or circulating air for heat exchange. For the energy storage system, this method of generating and recovering cold through the expansion refrigeration mechanism 3 greatly reduces the energy consumption of the air liquefaction process, and at the same time, the cold transfer path is shorter and more efficient, thereby achieving the optimal configuration of the system energy. In addition, the operation of the expansion refrigeration mechanism 3 forms a synergistic effect with the storage mechanism 4 and the expansion power generation mechanism 5, and can provide the system with necessary cold support under different working conditions of peak and valley power consumption, so that the efficiency of the energy storage cycle can be significantly improved. Therefore, the expansion refrigeration mechanism 3 is not only an important means to reduce the energy consumption of air liquefaction, but also a core link to improve the operating efficiency of the entire liquefied air energy storage system, reduce energy loss, and achieve economy.

[0031] In summary, the present application closely combines the processing and circulation of air with the recovery of cold energy. When the power consumption is low, the air processing mechanism 1 receives the atmospheric air and pre-processes it. The processed air is sent to the heat exchange mechanism 2, and is cooled to a gas-liquid two-phase mixture state through heat exchange, wherein the liquid part is stored in the storage mechanism 4 for subsequent power generation needs, and the gaseous part (i.e., the circulating air) continues to mix with the refrigerated air generated by the expansion refrigeration mechanism 3 and then exchanges heat with the processed air. This circulation path after gas-liquid separation ensures the maximum utilization of cold energy, not only storing liquid air through gas-liquid separation, but also recovering the cold energy of the gaseous part and reintroducing it into the heat exchange process, reducing the loss of cold energy; when the power consumption is high, the system takes out the liquid air from the storage mechanism 4 and sends it back to the heat exchange mechanism, and vaporizes it into air to be used for power generation through heat exchange. Liquid air absorbs a lot of heat during the vaporization process, and this part of heat comes from the heat exchange mechanism 2 of the system, which means that the cold energy stored during the low power consumption can be fully recovered and converted into refrigeration capacity. In addition, this cycle avoids multiple energy losses caused by indirect transfer of cold in traditional technologies. Cold is directly and efficiently transferred within the system, which improves the utilization efficiency of cold energy. In the power generation stage, the expansion component in the expansion power generation mechanism 5 converts the internal energy of the air to be generated into mechanical energy through the expansion process of the air to be generated, and drives the power generation component to generate electricity. During the expansion process, the air temperature decreases to generate cold, which can be mixed with the circulating air in the system to further cool the processed air, thereby further improving the cold recovery efficiency and recycling rate of the system.

[0032] Further, such as Figure 2 As shown, the air processing mechanism 1 includes an air filter 11, an air compressor 12, a first cooler 13, a first processing control valve 14 and a second processing control valve 15. One end of the first processing control valve 14 is connected to the air filter 11, and the other end is connected to one end of the air compressor 12. The other end of the air compressor 12 is connected to one end of the first cooler 13. The other end of the first cooler 13 is connected to one end of the second processing control valve 15. The other end of the second processing control valve 15 is connected to the first gas input end of the heat exchange mechanism 2.

[0033] In this embodiment, in the air processing mechanism 1, the main function of the air filter 11 is to receive atmospheric air through the first processing control valve 14 connected thereto, and filter mechanical impurities such as dust and particulate matter in the air to ensure that the air entering the subsequent equipment is clean, thereby protecting the operating efficiency and stability of the downstream equipment. The first processing control valve 14 plays the role of regulating and controlling the air flow. One end of it is connected to the air filter 11, and the other end is connected to one end of the air compressor 12 to ensure that the filtered air enters the air compressor 12 under a controlled state. The air compressor 12 increases its pressure by compressing air to provide the necessary high-pressure conditions for the subsequent liquefaction process. The other end of the air compressor 12 is connected to one end of the first cooler 13 through a pipeline. The first cooler 13 is responsible for preliminary cooling of the compressed high-temperature air to reduce the air temperature and reduce the energy consumption in the subsequent liquefaction process. The other end of the first cooler 13 is connected to one end of the second processing control valve 15 through a pipeline. The second processing control valve 15 further precisely regulates the flow and pressure of the cooled air and ensures that the air enters the first gas input end of the heat exchange mechanism 2 in a suitable state, thereby providing stable and controllable air fluid input conditions for the subsequent heat exchange and liquefaction process. The entire connection logic is designed to gradually process the air from the atmospheric state into high-quality air that meets the subsequent heat exchange and liquefaction requirements. Through the sequential connection of each port and the precise control of each link, the cleanliness, pressure and temperature conditions of the air at different processing stages are guaranteed, forming a complete set of air pretreatment and delivery mechanisms.

[0034] In summary, the air can be effectively filtered, compressed and cooled, thereby removing impurities from the air and reducing the air temperature, creating good process conditions for subsequent air liquefaction and heat exchange, avoiding the adverse effects of impurities and high temperature on equipment and system operation, and improving the efficiency and stability of air processing.

[0035] Further, such as Figure 2 As shown, the air processing mechanism 1 also includes a gas-liquid separator 16, a molecular sieve adsorber 17, a spherical tank 18 and a third processing control valve 19. One end of the gas-liquid separator 16 is connected to the other end of the second processing control valve 15, the other end of the gas-liquid separator 16 is connected to one end of the molecular sieve adsorber 17, the other end of the molecular sieve adsorber 17 is connected to one end of the spherical tank 18, the other end of the spherical tank 18 is connected to one end of the third processing control valve 19, and the other end of the third processing control valve 19 is connected to the first gas input end of the heat exchange mechanism 2.

[0036] In this embodiment, in the air processing mechanism 1, the function of the gas-liquid separator 16 is to separate the gas and liquid of the cooling air output from the second processing control valve 15. One end of the gas-liquid separator 16 is connected to the other end of the second processing control valve 15 through a pipeline to receive the air that has been cooled and controlled by the first cooler 13. Since the cooled air may contain free moisture and condensate, the gas-liquid separator 16 separates these liquid impurities to ensure that the air entering the subsequent equipment is dry gas, thereby avoiding the freezing of liquid impurities under low-temperature conditions to cause pipeline blockage or degradation of heat exchanger performance. The other end of the gas-liquid separator 16 is connected to one end of the molecular sieve adsorber 17 through a pipeline, and the molecular sieve adsorber 17 further removes trace moisture, carbon dioxide and organic hydrocarbon impurities in the air. These impurities may cause freezing blockage or form explosive mixtures during the low-temperature liquefaction process, so the function of the molecular sieve adsorber 17 is to ensure that the air entering the liquefaction process has high purity and safety. The other end of the molecular sieve adsorber 17 is connected to one end of the spherical tank 18 through a pipeline. The main function of the spherical tank 18 in the entire air processing process is to buffer and stabilize the pressure and flow of the air flow, so as to avoid uneven air flow or unstable pressure entering the subsequent equipment due to fluctuations in the front-end processing; and when the power consumption is low, it must complete two tasks, namely, the storage of liquid and the storage of pressurized gas (the spherical tank 18 is full of pressurized gas), so that when the power consumption is expanded at a peak, the pressurized gas in the spherical tank 18 can be released for liquefied storage. The other end of the spherical tank 18 is connected to one end of the third processing control valve 19 through a pipeline. The third processing control valve 19 is responsible for the final flow regulation and pressure control of the processed air to ensure that it enters the first gas input end of the heat exchange mechanism 2 in a suitable state. The entire connection logic, through the sequential action of each structural component, enables the air to separate from the gas and liquid after preliminary cooling, remove impurities, stabilize the pressure and flow, and finally achieve precise control of the fluid parameters, providing high-quality and stable air fluid input for the subsequent heat exchange and liquefaction process, while also ensuring the safety and efficiency of the system operation.

[0037] In summary, the gas-liquid separator 16 can be used to remove free water in the air, and the molecular sieve adsorber 17 can be used to further remove moisture, carbon dioxide and organic hydrocarbon impurities to prevent impurities from freezing and clogging pipes and devices under low temperature conditions. At the same time, the spherical tank 18 can be used to stabilize the storage pressure and flow of the air to ensure the purity and process requirements of the air before it enters the heat exchange mechanism 2, thereby improving the safety and liquefaction efficiency of the system.

[0038] Further, such as Figure 3As shown, the heat exchange mechanism 2 includes a first plate-fin heat exchanger 21, a second plate-fin heat exchanger 22 and a heat exchange throttle valve 23, the first heat medium input end of the first plate-fin heat exchanger 21 is connected to the first gas output end of the air processing mechanism 1, the first heat medium output end of the first plate-fin heat exchanger 21 is connected to the first heat medium input end of the second plate-fin heat exchanger 22, the first heat medium output end of the second plate-fin heat exchanger 22 is connected to one end of the heat exchange throttle valve 23, and the other end of the heat exchange throttle valve 23 is connected to the gas-liquid input end of the storage mechanism 4.

[0039] In this embodiment, in the heat exchange mechanism 2, the first heat medium input end of the first plate-fin heat exchanger 21 is connected to the first gas output end of the air processing mechanism 1 through a pipeline, and is used to receive the processed air processed by the air processing mechanism 1. The main function of the first plate-fin heat exchanger 21 is to preliminarily cool the incoming high-temperature and high-pressure processed air, and reduce the temperature of the processed air through heat exchange, laying the foundation for the subsequent liquefaction process of the processed air. The processed air after preliminary cooling flows out from the first heat medium output end of the first plate-fin heat exchanger 21, and enters the first heat medium input end of the second plate-fin heat exchanger 22 through a pipeline. The second plate-fin heat exchanger 22 further deeply cools the processed air, uses a lower temperature cold medium to exchange heat with the processed air, and reduces the temperature of the processed air to close to the liquefaction point, creating the required low temperature conditions for the liquefaction process of the processed air. The processed air after deep cooling flows out from the first heat medium output end of the second plate-fin heat exchanger 22, and enters one end of the heat exchange throttle valve 23 through a pipeline.

[0040] The function of the heat exchange throttle valve 23 is to further reduce the temperature of the processed air by throttling and reducing the pressure, and at the same time convert the cooled processed air into a gas-liquid two-phase mixture. The liquid processed air in the gas-liquid two-phase mixture needs to be transported to the storage mechanism 4 for storage, and this transportation process is achieved by connecting the other end of the heat exchange throttle valve 23 with the gas-liquid input end of the storage mechanism 4. The entire heat exchange mechanism 2 realizes the full-process cooling treatment from preliminary cooling of the processed air to deep cooling of the processed air, and then to the final throttling liquefaction of the processed air, ensuring the high efficiency and low energy consumption of the liquefaction process of the processed air. At the same time, the first plate-fin heat exchanger 21 and the second plate-fin heat exchanger 22 realize large-area heat exchange in a limited volume through their compact and efficient design, improve the heat exchange efficiency of the processed air, and significantly reduce the loss of cooling capacity. The precise control of the heat exchange throttle valve 23 ensures that the changes in pressure and temperature during the liquefaction of the processed air meet the design requirements, and provides stable process conditions for the storage of liquid processed air. The functions and connection relationships of each structural component complement each other, and together they complete the core cooling task of the key step of air liquefaction after processing, providing a strong guarantee for the efficient operation of the entire energy storage system.

[0041] In summary, the processed air can be cooled in multiple stages by the first plate-fin heat exchanger 21 and the second plate-fin heat exchanger 22, and the gas can be depressurized and cooled by the heat exchange throttle valve 23, so that the air can quickly form a gas-liquid two-phase mixture during the heat exchange process, thereby effectively reducing the energy consumption of the air liquefaction process and improving the cold utilization rate and liquefaction efficiency.

[0042] Further, such as Figure 3 As shown, the expansion refrigeration mechanism 3 includes a refrigeration expander 31 and a refrigeration throttle valve 32, and the refrigeration expander 31 includes a compression end 311 and an expansion end 312; One end of the compression end 311 is connected to one end of the refrigeration throttle valve 32, the other end of the refrigeration throttle valve 32 is connected to the second gas output end of the air processing mechanism 1, the other end of the compression end 311 is connected to the second heat medium input end of the first plate-fin heat exchanger 21, the second heat medium output end of the first plate-fin heat exchanger 21 is connected to the second heat medium input end of the second plate-fin heat exchanger 22, and the second heat medium output end of the second plate-fin heat exchanger 22 is connected to one end of the heat exchange throttle valve 23; One end of the expansion end 312 is connected to the second heat medium input end of the second plate-fin heat exchanger 22, the first cold medium input end of the second plate-fin heat exchanger 22 is connected to the gas output end of the storage mechanism 4, the first cold medium output end of the second plate-fin heat exchanger 22 is connected to the first cold medium input end of the first plate-fin heat exchanger 21, the first cold medium output end of the first plate-fin heat exchanger 21 is connected to the atmosphere, or is connected to the gas input end of the air processing mechanism 1, and the pipeline between the first cold medium input end of the second plate-fin heat exchanger 22 and the liquid input end of the heat exchange mechanism 2 is connected to the other end of the expansion end 312.

[0043] In this embodiment, in the expansion refrigeration mechanism 3, one end of the compression end 311 of the refrigeration expander 31 is connected to one end of the refrigeration throttle valve 32 through a pipeline. The main function of the refrigeration throttle valve 32 is to throttle and reduce the pressure of the high-pressure processed air delivered by the air processing mechanism 1 through the second gas output end, thereby reducing the temperature of the processed air and creating suitable initial conditions for the subsequent expansion refrigeration process. The other end of the refrigeration throttle valve 32 is connected to the second gas output end of the air processing mechanism 1 to ensure that the throttled processed air can enter the compression end 311 of the refrigeration expander 31. In the refrigeration expander 31, the compression end 311 further compresses and transfers the incoming processed air to make its pressure and temperature meet the design requirements, and then the processed air is delivered to the second heat medium input end of the first plate-fin heat exchanger 21 through the other end of the compression end 311.

[0044] After the first plate-fin heat exchanger 21 receives the processed air from the compression end 311, it further reduces the temperature of the processed air by heat exchange with the cold medium, and transmits it from the second heat medium output end of the first plate-fin heat exchanger 21 to the second heat medium input end of the second plate-fin heat exchanger 22. The second plate-fin heat exchanger 22 further receives the cooled processed air, and further deeply cools the air through the cold medium with a lower temperature to achieve the low temperature condition required for expansion. The cooled processed air flows back to one end of the heat exchange throttle valve 23 from the second heat medium output end of the second plate-fin heat exchanger 22, forming a continuous cooling and regulation loop.

[0045] One end of the expansion end 312 of the refrigeration expander 31 is connected to the second heat medium input end of the second plate-fin heat exchanger 22, so as to receive the fully cooled processed air, and further reduce the pressure and temperature of the air by expansion at the expansion end 312, and release a large amount of cold capacity for the system to use in the process. The cooling capacity of the expansion end 312 is used to further process the circulating air generated during the liquefaction process, and the other end of the expansion end 312 is connected to the connection between the liquid input end of the heat exchange mechanism 2 and the first cold medium input end of the second plate-fin heat exchanger 22 through a pipeline, so as to introduce the expanded cold air into the deep cold cycle for further use by the storage mechanism 4 or the heat exchange mechanism 2.

[0046] During the cold medium circulation process, the first cold medium input end of the second plate-fin heat exchanger 22 is connected to the gas output end of the storage mechanism 4, and is used to receive the gaseous liquefied air released by the storage mechanism 4 as a cold medium source. The gaseous liquefied air is further cooled in the second plate-fin heat exchanger 22, and then flows from the first cold medium output end of the second plate-fin heat exchanger 22 to the first cold medium input end of the first plate-fin heat exchanger 21, and completes the heat exchange process with the processed air in the first plate-fin heat exchanger 21, and finally flows from the first cold medium output end to the atmosphere, or is led back to the gas input end of the air processing mechanism 1 for recycling. Through this complete structural component connection logic and process design, the expansion refrigeration mechanism 3 realizes multi-stage efficient processing of compression, throttling, cooling and expansion of the processed air, which not only provides deep cold conditions for the system, but also significantly reduces the energy consumption of liquefied air through cold recovery and reuse, ensuring the efficient operation of the entire energy storage system and the maximization of cold energy utilization.

[0047] In summary, the air can be circulated and cooled by heat exchange through the compression end and expansion end of the refrigeration expander 31 in combination with the refrigeration throttle valve 32, and the cold released during the expansion process is transferred to the air or cold medium in the heat exchange mechanism 2, thereby efficiently recovering the cold and reducing the external refrigeration demand of the system, significantly improving the utilization rate of the cold, and reducing the energy consumption of liquefied air.

[0048] Further, such as Figure 3 As shown, a second cooler 33 is connected between the other end of the compression end 311 and the second heat medium input end of the first plate-fin heat exchanger 21 .

[0049] In this embodiment, in the expansion refrigeration mechanism 3, the other end of the compression end 311 of the refrigeration expander 31 is connected to the second heat medium input end of the first plate-fin heat exchanger 21 through a pipeline, and the second cooler 33 arranged between the two further optimizes the cooling process of the processed air. Specifically, the main function of the compression end 311 is to compress the processed air from the refrigeration throttle valve 32, so that the pressure of the air increases, and the air temperature also rises accordingly. Although such high-pressure air provides the necessary pressure conditions for subsequent heat exchange, its high temperature state may affect the subsequent heat exchange efficiency of the first plate-fin heat exchanger 21. Therefore, adding a second cooler 33 between the compression end 311 and the first plate-fin heat exchanger 21 can perform intermediate cooling on the compressed high-temperature and high-pressure processed air, thereby reducing the temperature of the air and making it enter the first plate-fin heat exchanger 21 in a more suitable initial state.

[0050] The second cooler 33 reduces the temperature of the processed air to the temperature range required by the first plate-fin heat exchanger 21, which not only improves the heat exchange efficiency, but also reduces the heat load of the plate-fin heat exchanger and prolongs its service life. At the same time, the introduction of the second cooler 33 can also avoid the problem of cold loss due to excessive heat transfer of high-temperature air to the cold medium, making the use of cold more efficient. In addition, the second cooler 33 can further adjust the state of the compressed air so that it has more stable flow and temperature conditions when entering the first plate-fin heat exchanger 21, thereby ensuring the stability and controllability of the entire heat exchange process.

[0051] The cooling and heat exchange efficiency of the expansion refrigeration mechanism 3 is significantly optimized by using the second cooler 33 as an important intermediate link between the compression end 311 and the first plate-fin heat exchanger 21. In system operation, the second cooler 33 not only plays a key role in the cryogenic refrigeration process, but also creates more ideal conditions for subsequent cryogenic cooling of processed air through its precise cooling control, further improving the overall performance and energy efficiency of the liquefied air energy storage system.

[0052] In summary, the air temperature can be further lowered by combining the compression end 311 of the refrigeration expansion machine 31 with the second cooler 33, thereby improving the initial cooling effect of air liquefaction on the basis of compression cooling, providing a lower initial temperature for the multi-stage heat exchange in the plate-fin heat exchanger, optimizing the cold transfer efficiency, and further reducing the energy consumption of air liquefaction.

[0053] Further, such as Figure 3As shown, the storage mechanism 4 includes a storage control valve 41, a liquid storage tank 42 and a liquid air pump 43, the gas-liquid input end of the liquid storage tank 42 is connected to the other end of the heat exchange throttle valve 23, the gas output end of the liquid storage tank 42 is connected to one end of the storage control valve 41, the other end of the storage control valve 41 is connected to the first cold medium input end of the second plate-fin heat exchanger 22, the liquid output end of the liquid storage tank 42 is connected to one end of the liquid air pump 43, the other end of the liquid air pump 43 is connected to the second cold medium input end of the second plate-fin heat exchanger 22, the second cold medium output end of the second plate-fin heat exchanger 22 is connected to the second cold medium input end of the first plate-fin heat exchanger 21, and the second cold medium output end of the first plate-fin heat exchanger 21 is connected to the gas input end of the expansion power generation mechanism 5.

[0054] In this embodiment, in the storage mechanism 4, the gas-liquid input end of the liquid storage tank 42 is connected to the other end of the heat exchange throttle valve 23 through a pipeline, and is used to receive the gas-liquid two-phase mixture output from the heat exchange throttle valve 23. The heat exchange throttle valve 23 cools the processed air from the heat exchange mechanism 2 to a liquefied state through throttling, and the liquid part enters the liquid storage tank 42 for storage, while the gaseous part can be transported to the storage control valve 41 through the gas output end of the liquid storage tank 42. The main function of the storage control valve 41 is to adjust the flow of gaseous air so that it enters the first cold medium input end of the second plate-fin heat exchanger 22 at a stable speed and pressure, so as to participate in the subsequent heat exchange process. In the second plate-fin heat exchanger 22, these gaseous airs are used as cold media to exchange heat with the processed air, transfer their own coldness to the air to be cooled, and their own temperature gradually rises, and finally flows from the first cold medium output end of the second plate-fin heat exchanger 22 to the heat exchange equipment of the next stage.

[0055] The liquid output end of the liquid storage tank 42 is connected to one end of the liquid air pump 43 through a pipeline. The function of the liquid air pump 43 is to pressurize the stored liquid air and transport it to the second cold medium input end of the second plate-fin heat exchanger 22. The liquid air pump 43 pressurizes the liquid air so that it has a suitable pressure condition when entering the second plate-fin heat exchanger 22, so as to carry out efficient heat exchange. In the second plate-fin heat exchanger 22, the liquid air transported by the liquid air pump 43 partially vaporizes after absorbing heat, and flows from the second cold medium output end to the second cold medium input end of the first plate-fin heat exchanger 21 in the form of cold medium. The first plate-fin heat exchanger 21 further cools the cold medium so that it can fully exchange heat with the high-temperature processed air during the heat exchange process, and reduces the temperature of the processed air to the design requirements. After the cold medium is cooled by the first plate-fin heat exchanger 21, it flows from its second cold medium output end to the gas input end of the expansion power generation mechanism 5, providing suitable cooling conditions for the subsequent expansion power generation process.

[0056] Through the storage mechanism 4, in cooperation with the liquid storage tank 42, the storage control valve 41 and the liquid air pump 43, the liquid air can be stably stored and pressurized for transportation, and the flow of gaseous air can be adjusted to participate in cold recovery. At the same time, the liquid storage tank 42 effectively realizes the separation and storage of gas and liquid phases, ensuring the recycling efficiency of the cold medium. The pressurization function of the liquid air pump 43 ensures the energy transfer efficiency of the liquid air in the subsequent heat exchange, and the storage control valve 41 optimizes the utilization conditions of the cold medium by accurately controlling the flow and pressure of the gaseous air. The whole system is rigorously designed and clearly functional, so that the cold of liquid and gaseous air can be fully utilized, which not only reduces the energy consumption in the liquefaction process, but also provides reliable support for the efficient and stable operation of the system.

[0057] In summary, the liquid air can be stably stored through the liquid storage tank 42 in the storage mechanism 4, and the liquid air can be output to the heat exchange mechanism 2 in combination with the liquid air pump 43 to achieve stable transportation and reuse of the liquid air. At the same time, the discharge flow of the gaseous air in the storage tank is adjusted by the storage control valve 41 to ensure the stability of the liquid level in the storage tank, thereby optimizing the liquefied air storage and transportation process and ensuring the continuity and efficiency of the system operation.

[0058] Further, such as Figure 3 As shown, the power generation component includes a first generator 51 and a second generator 52, and the expansion component includes a first power generation expander 53 for driving the first generator 51 to generate electricity, and a second power generation expander 54 for driving the second generator 52 to generate electricity. One end of the first power generation expander 53 is connected to the second cold medium output end of the first plate-fin heat exchanger 21, and the other end of the first power generation expander 53 is connected to the third cold medium input end of the first plate-fin heat exchanger 21. The third cold medium output end of the first plate-fin heat exchanger 21 is connected to one end of the second power generation expander 54, and the other end of the second power generation expander 54 is connected to the atmosphere, or is connected to the gas input end of the air processing mechanism 1.

[0059] In this embodiment, in the power generation component, the expansion component includes a first power generation expander 53 and a second power generation expander 54, and the two expanders respectively drive the first generator 51 and the second generator 52 to complete the output of electric energy. One end of the first power generation expander 53 is connected to the second cold medium output end of the first plate-fin heat exchanger 21 through a pipeline, and is used to receive the cooling air after heat exchange in the first plate-fin heat exchanger 21 as expansion gas to enter the expander. When the cooling air enters the first power generation expander 53, its pressure and temperature are both low. The expander uses its pressure difference to convert the potential energy in the air into mechanical energy through expansion, driving the first generator 51 to generate electricity, and the temperature of the air is further reduced during the expansion process.

[0060] The other end of the first power generation expander 53 is connected to the third cold medium input end of the first plate-fin heat exchanger 21 through a pipeline, and the expanded air flows back to the first plate-fin heat exchanger 21, and partial recovery of cold is completed through further heat exchange. This cold recovery process not only reduces the energy loss of the expanded air, but also provides more suitable gas conditions for the subsequent second power generation expander 54. The expanded air treated by the first plate-fin heat exchanger 21 flows from the third cold medium output end to one end of the second power generation expander 54. After receiving the air, the second power generation expander 54 expands it again, and by further reducing the gas pressure, its internal energy is converted into mechanical energy, driving the second generator 52 to generate electricity, while further reducing the temperature and pressure of the air.

[0061] The other end of the second power generation expander 54 is connected to the atmosphere through a pipeline, or connected to the gas input end of the air processing mechanism 1. If connected to the atmosphere, the expanded post-power generation air is discharged to the outside; if connected to the air processing mechanism 1, the expanded post-power generation air can flow back into the system as circulating gas, providing a suitable gas source for the air processing mechanism 1. This connection logic ensures that the gas can flexibly choose the method of discharge or recycling after completing the energy conversion, thereby optimizing the overall energy utilization efficiency of the system.

[0062] The linkage design of the first power generation expander 53 and the second power generation expander 54 realizes staged expansion and power generation, and converts the mechanical energy released during the expansion process into electrical energy output in a graded manner. This hierarchical design not only avoids the energy waste caused by a single expansion, but also improves the efficiency of expansion power generation through multi-stage expansion. In addition, through the third cold medium input and output ends of the first plate-fin heat exchanger 21, the expanded cold air can be partially recovered and reused, further optimizing the system's cold management and energy efficiency. The entire system reasonably designs the connection relationship of the ports so that the cooling air can efficiently participate in the cycle of expansion power generation and cold recovery, providing an efficient and stable energy output solution for the liquefied air energy storage system.

[0063] In summary, the expansion component can drive the operation of the power generation component, and the first power generation expander 53 and the second power generation expander 54 work together to achieve multi-stage expansion power generation, and the internal energy of the vaporized liquid air is converted into mechanical energy to drive the generator to generate electricity, thereby improving the energy utilization efficiency of the expansion process and improving the overall power generation efficiency of the energy storage system.

[0064] Further, such as Figure 3 As shown, a first heater 55 is provided between one end of the first power generation expander 53 and the second cold medium output end of the first plate-fin heat exchanger 21 , and a second heater 56 is provided between the third cold medium output end of the first plate-fin heat exchanger 21 and one end of the second power generation expander 54 .

[0065] In this embodiment, in the system, in order to optimize the energy conversion efficiency of expansion power generation, a first heater 55 is provided between one end of the first power generation expander 53 and the second cold medium output end of the first plate-fin heat exchanger 21. The function of the first heater 55 is to heat the cooling air output from the first plate-fin heat exchanger 21 so that the cooling air enters the first power generation expander 53 after its temperature is appropriately increased. Since the work capacity of the expander is closely related to the temperature difference and pressure difference of the incoming gas, preheating the cooling air by the first heater 55 can increase the internal energy released by the gas during the expansion process, thereby enhancing the work capacity of the first power generation expander 53 and improving the efficiency of driving the first generator 51 to generate electricity.

[0066] The expanded air coming out of the first power generation expander 53 returns to the third cold medium input end of the first plate-fin heat exchanger 21 through the pipeline, completes the recovery of part of the cold capacity in the first plate-fin heat exchanger 21, and flows from its third cold medium output end to one end of the second power generation expander 54. In order to further optimize the working capacity of the second power generation expander 54, a second heater 56 is arranged between the third cold medium output end of the first plate-fin heat exchanger 21 and one end of the second power generation expander 54. The second heater 56 reheats the expanded air after heat exchange in the first plate-fin heat exchanger 21, and further raises its temperature before sending it to the second power generation expander 54. This heating can not only increase the internal energy of the expanded gas and enhance the expansion efficiency of the second power generation expander 54, but also utilize the low-level heat source in the system to improve the comprehensive utilization efficiency of energy.

[0067] The setting of the first heater 55 and the second heater 56 forms an effective energy recovery and utilization mechanism, so that the gas that has been cooled and expanded can regain heat energy before entering the expander. This preheating design effectively avoids the energy loss caused by the direct expansion of cold air, while fully tapping the potential energy in the gas, thereby achieving the maximum energy output of multi-stage expansion power generation. In addition, this logical connection design ensures the continuity of gas processing between the first power generation expander 53 and the second power generation expander 54, which can not only maintain the stability of the airflow, but also improve the power generation efficiency of the entire system through two-stage expansion. The role of the first heater 55 and the second heater 56 runs through the entire expansion and power generation process, providing important optimization support for the energy conversion of the liquefied air energy storage system, so that it can achieve higher efficiency in the comprehensive utilization of cold energy and heat energy.

[0068] In summary, by setting a first heater 55 between the first power generation expander 53 and the plate-fin heat exchanger, and setting a second heater 56 between the second power generation expander 54 and the plate-fin heat exchanger, the expanded air can be heated to increase the initial temperature of the air before expansion, enhance the working capacity of the expander, and further improve the expansion power generation efficiency.

[0069] like Figure 4 As shown, a control method for a cold recovery system of a liquefied air energy storage system is applied to a cold recovery system of a liquefied air energy storage system, and the control method includes: S10, determining the current power consumption state, where the current power consumption state at least includes a power consumption valley and a power consumption peak; In this embodiment, determining the current power consumption status refers to judging the current power demand status by detecting the load conditions of the power grid in the system. The power consumption status is mainly divided into power trough and power peak. The power trough usually refers to the time period when the power grid load is low and the remaining power generation is large, while the power peak refers to the time period when the power grid load is high and the power demand is large. By monitoring the power grid load information in real time, the power consumption status can be accurately judged to provide basic data support for the operation of the liquefied air energy storage system. For example, in the late night period, the demand for industrial and residential electricity decreases, which may be judged as a power trough; and during the peak period of the day, the demand for electricity surges, which may be judged as a power peak.

[0070] S20, if the current power consumption state is at a low power consumption state, then obtain the liquid level data of the storage mechanism 4, and judge whether the liquid level data is less than the preset liquid level threshold value. If it is not less than the preset liquid level threshold value, then continue to judge. If it is less than the preset liquid level threshold value, then turn off the expansion power generation mechanism 5, turn on the air processing mechanism 1, the expansion refrigeration mechanism 3, the heat exchange mechanism 2 and the storage mechanism 4, so that the storage mechanism 4 stores liquid air until the liquid level data is greater than or equal to the preset liquid level threshold value. In this embodiment, obtaining the liquid level data of the storage mechanism 4 refers to real-time monitoring of the storage volume of liquid air in the liquid storage tank 42 through the liquid level sensor inside the storage mechanism 4, and comparing its data with the preset liquid level threshold. The liquid level data is used to determine whether the liquid air in the storage tank meets the design requirements of the system, and the preset liquid level threshold is a lower limit value set according to the system capacity and power generation demand. If the liquid level data is less than the threshold, it means that the liquid air storage is insufficient, and the corresponding refrigeration and liquefaction process needs to be started to replenish the storage volume. For example, when it is detected that the liquid level in the storage tank is only 30 of the design capacity, and the minimum threshold of the system is set to 50, the system will immediately start the liquefaction process until the liquid level returns to above the set value; closing the expansion power generation mechanism 5 refers to shutting down the expansion generator through the system control unit to prevent the consumption of the stored liquid air for power generation during the low electricity consumption period, and ensure that the liquid air can be used for storage first. During the low electricity consumption period with low electricity prices, the supply and demand of the power grid are unbalanced. At this time, closing the expansion power generation mechanism 5 can avoid the waste of system resources and reserve sufficient liquid air resources for peak electricity prices. For example, when it is judged that the power consumption is low, the expansion power generation mechanism 5 will be shut down immediately, and the stored liquid air will no longer be used for power generation, but will enter the storage tank for standby; starting the air processing mechanism 1, the expansion refrigeration mechanism 3, the heat exchange mechanism 2 and the storage mechanism 4 means to start the key units in the system in a coordinated manner, so that the system enters the working mode of liquefied air. The air processing mechanism 1 is responsible for receiving and processing air from the atmosphere, and converting it into processed air suitable for liquefaction through separation, adsorption and cooling. The expansion refrigeration mechanism 3 generates low-temperature cooling through the refrigeration expander 31, providing the necessary cold source for the air liquefaction process. The heat exchange mechanism 2 realizes the gradual cooling of the processed air through a multi-stage plate-fin heat exchanger, so that its temperature is reduced to close to the liquefaction point and then enters the storage mechanism 4. The storage mechanism 4 receives the liquefied air and stores it in the liquid storage tank 42 in liquid form. The whole process realizes the conversion and storage of valley power, laying the foundation for energy output during peak periods. For example, during off-peak hours, the electric energy drives the air compressor 12 and the refrigeration equipment to convert the atmospheric air into liquid air at about -190°C for storage.

[0071] S30. If the current power consumption state is at a peak, the expansion refrigeration mechanism 3 is turned off, and the air processing mechanism 1, the expansion power generation mechanism 5, the heat exchange mechanism 2 and the storage mechanism 4 are turned on to enable the expansion power generation mechanism 5 to generate electricity.

[0072] In this embodiment, shutting down the expansion refrigeration mechanism 3 means suspending the operation of the expansion refrigeration device through the control unit during peak power consumption, so as to concentrate system resources on the power generation link. The function of the expansion refrigeration mechanism 3 is to provide cooling capacity for liquefied air, and the liquid air has been stored during peak power consumption, and no additional refrigeration is required. Therefore, the system operation energy consumption can be saved by shutting down the expansion refrigeration mechanism 3. For example, during the high load period of the power grid, the expansion refrigeration unit will automatically shut down, and the stored liquid air will be used for the generator set first; starting the air processing mechanism 1, the expansion power generation mechanism 5, the heat exchange mechanism 2 and the storage mechanism 4 means starting these mechanisms in coordination during peak power consumption, and vaporizing the stored liquid air for expansion power generation. The air processing mechanism 1 can perform auxiliary gas treatment in this process to ensure that the gas entering the system meets the working requirements. The expansion power generation mechanism 5 converts the internal energy of the liquid air into mechanical energy to drive the generator through multi-stage expansion, and the heat exchange mechanism 2 provides the high-temperature and high-pressure gas required for expansion power generation through vaporization and heat exchange of the liquid air, and the storage mechanism 4 controls the stable output of the liquid air in this process to ensure the continuity and efficiency of the operation of the entire system. For example, when the grid load is at a peak, the liquid air in the storage mechanism 4 is pressurized by the liquid air pump 43 and then enters the heat exchanger for vaporization, and then enters the expander for expansion to generate electricity, thereby meeting the electricity demand during peak hours.

[0073] Specifically, when electricity consumption is low, air from the atmosphere passes through the air filter 11 to filter out mechanical impurities such as dust and then enters the air compressor 12 to be pressurized to 36 bar. The air compressor 12 adopts a 5-stage compression and inter-stage cooling form. The compressed air enters the first cooler 13 and is cooled to 40°C (the refrigeration throttle valve 32 controls the temperature of the cooled air by controlling the flow of the cooling medium), and enters the gas-liquid separator 16 through the second processing control valve 15 to remove free water (to reduce the water absorption load of the molecular sieve). The compressed and cooled air enters the molecular sieve adsorber 17 to remove moisture, carbon dioxide, organic hydrocarbons and other impurities in the air. In a low-temperature state, water and carbon dioxide will freeze and block pipes and heat exchangers, while organic hydrocarbons such as methane and ethylene will accumulate in the storage tank when stored at low temperature, and will form an explosion hazard with oxygen in the air. The air coming out of the molecular sieve adsorber 17 is divided into two streams after passing through the spherical tank 18. One stream directly enters the first plate-fin heat exchanger 21 and the second plate-fin heat exchanger 22 through the third process control valve 19 to be cooled to -175°C to become liquid air, and then enters the heat exchange throttle valve 23. After throttling, the pressure is 1.2 bar to form a gas-liquid two-phase mixture, which enters the liquid storage tank 42 for storage. The gas reflux enters the first plate-fin heat exchanger 21 and the second plate-fin heat exchanger 22 respectively to recover the cold energy and then returns to the inlet of the air compressor 12.

[0074] Another stream of processed air, through the refrigeration throttle valve 32, controls its flow rate to enter the compression end 311 of the refrigeration expander 31 to recover the expansion work of the expander, thereby increasing the inlet pressure of the refrigeration expander 31 and increasing the refrigeration capacity of the refrigeration expander 31. The air exiting the compression end 311 of the refrigeration expander 31 enters the first plate-fin heat exchanger 21 and the second plate-fin heat exchanger 22 for cooling, and is extracted from the second plate-fin heat exchanger 22 to enter the refrigeration expander 31 for expansion and refrigeration after being cooled to -90°C. The expanded low-temperature air is combined with the circulating air throttled by the heat exchange throttle valve 23 and enters the heat exchange mechanism 2 for reheating, and the reheated air is discharged into the atmosphere.

[0075] During peak electricity consumption, the liquefied air stored in the liquid storage tank 42 is pressurized to 120 bar by the liquid air pump, and then vaporized by the first plate-fin heat exchanger 21 and the second plate-fin heat exchanger 22. The air temperature out of the heat exchange mechanism is 35°C, and enters the first heater 55, heated to 130°C, and then enters the first power generation expander 53 to expand and do work, while driving the first generator 51 to generate electricity. The pressure after expansion is 10 bar, and the air temperature after expansion is reduced. The low-temperature air enters the first plate-fin heat exchanger 21 to be reheated to 35°C (TI-22), enters the second heater 56 to be heated to 130°C, enters the second power generation expander 54 to expand and do work, and drives the second generator 52 to generate electricity. The pressure after expansion is 1.2 bar, and the expanded air returns to the compressor inlet, completing the cycle process of liquefaction storage and expansion power generation.

[0076] To summarize, the storage state of the liquid air during the low electricity consumption period can be determined in real time through the liquid level data of the storage mechanism, the operating states of the air processing mechanism, the expansion refrigeration mechanism and the storage mechanism can be flexibly controlled, and the liquefaction storage process can be started in time when the liquid level is insufficient to ensure the stability of the reserves of liquid air in the storage mechanism, thereby ensuring the power generation demand during the subsequent peak electricity consumption period; the expansion refrigeration mechanism can be shut down in real time according to the power demand during the peak electricity consumption period, and the air processing mechanism, the expansion power generation mechanism and the heat exchange mechanism can be started at the same time to efficiently convert the liquid air in the storage mechanism into expanded power generation air, and drive the generator to generate electricity through expansion work, thereby ensuring the efficiency and stability of the power generation process, thereby meeting the power supply demand during the peak electricity consumption period and improving the responsiveness and adaptability of the system operation.

[0077] Those skilled in the art can clearly understand that for the convenience and simplicity of description, only the division of the above-mentioned functional units and modules is used as an example. In actual applications, the above-mentioned functions can be distributed and completed by different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above.

[0078] The embodiments described above are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, a person skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be included in the protection scope of the present application.

Claims

1. A cold recovery system for a liquefied air energy storage system, characterized in that: The cold energy recovery system of a liquefied air energy storage system comprises an air processing mechanism (1), a heat exchange mechanism (2), an expansion refrigeration mechanism (3), a storage mechanism (4) and an expansion power generation mechanism (5); The gas input end of the air processing mechanism (1) is used to receive air, and the air processing mechanism (1) is used to process air to form processed air. The first gas output end of the air processing mechanism (1) is connected to the first gas input end of the heat exchange mechanism (2), the gas-liquid output end of the heat exchange mechanism (2) is connected to the gas-liquid input end of the storage mechanism (4), the gas output end of the storage mechanism (4) is connected to the second gas input end of the heat exchange mechanism (2), the second gas output end of the air processing mechanism (1) is connected to the compression end of the expansion refrigeration mechanism (3), and the gas input end of the expansion refrigeration mechanism (3) is connected to the first gas input end of the heat exchange mechanism (2). The gas output end of the heat exchange mechanism (2) is connected to the gas-liquid output end of the storage mechanism (4), the pipeline between the gas-liquid output end of the heat exchange mechanism (2) and the gas-liquid input end of the storage mechanism (4) is connected to the gas output end of the expansion refrigeration mechanism (3), the second gas output end of the heat exchange mechanism (2) is connected to the atmosphere, or is connected to the gas input end of the air processing mechanism (1), the liquid output end of the storage mechanism (4) is connected to the liquid input end of the heat exchange mechanism (2), the third gas output end of the heat exchange mechanism (2) is connected to the gas input end of the expansion power generation mechanism (5), and the gas output end of the expansion power generation mechanism (5) is connected to the atmosphere, or is connected to the gas input end of the air processing mechanism (1); When the power consumption is low, the processed air is heat-exchanged into a gas-liquid two-phase mixture after entering the heat exchange mechanism (2), the liquid air in the gas-liquid two-phase mixture is stored in the storage mechanism (4), and the circulating air in the gas-liquid two-phase mixture is mixed with the refrigeration air output from the gas output end of the expansion refrigeration mechanism (3), and then heat-exchanged with the processed air; When the power consumption is at a peak, the storage mechanism (4) outputs liquid air to the heat exchange mechanism (2) for heat exchange to vaporize into air to be used for power generation. The expansion power generation mechanism (5) comprises an expansion component and a power generation component. The air to be used for power generation enters the expansion component to expand and perform work, thereby driving the power generation component to generate electricity.

2. A cold energy recovery system for a liquefied air energy storage system according to claim 1, characterized in that: The air processing mechanism (1) comprises an air filter (11), an air compressor (12), a first cooler (13), a first processing control valve (14) and a second processing control valve (15); one end of the first processing control valve (14) is connected to the air filter (11), and the other end is connected to one end of the air compressor (12); the other end of the air compressor (12) is connected to one end of the first cooler (13); the other end of the first cooler (13) is connected to one end of the second processing control valve (15); and the other end of the second processing control valve (15) is connected to a first gas input end of the heat exchange mechanism (2).

3. A cold energy recovery system for a liquefied air energy storage system according to claim 2, characterized in that: The air processing mechanism (1) further comprises a gas-liquid separator (16), a molecular sieve adsorber (17), a spherical tank (18) and a third processing control valve (19); one end of the gas-liquid separator (16) is connected to the other end of the second processing control valve (15); the other end of the gas-liquid separator (16) is connected to one end of the molecular sieve adsorber (17); the other end of the molecular sieve adsorber (17) is connected to one end of the spherical tank (18); the other end of the spherical tank (18) is connected to one end of the third processing control valve (19); and the other end of the third processing control valve (19) is connected to the first gas input end of the heat exchange mechanism (2).

4. The cold recovery system of a liquefied air energy storage system according to claim 1, characterized in that: The heat exchange mechanism (2) comprises a first plate-fin heat exchanger (21), a second plate-fin heat exchanger (22) and a heat exchange throttle valve (23); the first heat medium input end of the first plate-fin heat exchanger (21) is connected to the first gas output end of the air processing mechanism (1); the first heat medium output end of the first plate-fin heat exchanger (21) is connected to the first heat medium input end of the second plate-fin heat exchanger (22); the first heat medium output end of the second plate-fin heat exchanger (22) is connected to one end of the heat exchange throttle valve (23); and the other end of the heat exchange throttle valve (23) is connected to the gas-liquid input end of the storage mechanism (4).

5. A cold energy recovery system for a liquefied air energy storage system according to claim 4, characterized in that: The expansion refrigeration mechanism (3) comprises a refrigeration expansion machine (31) and a refrigeration throttle valve (32); the refrigeration expansion machine (31) comprises a compression end (311) and an expansion end (312); One end of the compression end (311) is connected to one end of the refrigeration throttle valve (32), the other end of the refrigeration throttle valve (32) is connected to the second gas output end of the air processing mechanism (1), the other end of the compression end (311) is connected to the second heat medium input end of the first plate-fin heat exchanger (21), the second heat medium output end of the first plate-fin heat exchanger (21) is connected to the second heat medium input end of the second plate-fin heat exchanger (22), and the second heat medium output end of the second plate-fin heat exchanger (22) is connected to one end of the heat exchange throttle valve (23); One end of the expansion end (312) is connected to the second heat medium input end of the second plate-fin heat exchanger (22), the first cold medium input end of the second plate-fin heat exchanger (22) is connected to the gas output end of the storage mechanism (4), the first cold medium output end of the second plate-fin heat exchanger (22) is connected to the first cold medium input end of the first plate-fin heat exchanger (21), the first cold medium output end of the first plate-fin heat exchanger (21) is connected to the atmosphere, or is connected to the gas input end of the air processing mechanism (1), and the pipeline between the first cold medium input end of the second plate-fin heat exchanger (22) and the liquid input end of the heat exchange mechanism (2) is connected to the other end of the expansion end (312).

6. A cold energy recovery system for a liquefied air energy storage system according to claim 5, characterized in that: A second cooler (33) is connected between the other end of the compression end (311) and the second heat medium input end of the first plate-fin heat exchanger (21).

7. The cold recovery system of a liquefied air energy storage system according to claim 5, characterized in that: The storage mechanism (4) comprises a storage control valve (41), a liquid storage tank (42) and a liquid air pump (43); the gas-liquid input end of the liquid storage tank (42) is connected to the other end of the heat exchange throttle valve (23); the gas output end of the liquid storage tank (42) is connected to one end of the storage control valve (41); the other end of the storage control valve (41) is connected to the first cold medium input end of the second plate-fin heat exchanger (22); the liquid output end of the liquid storage tank (42) is connected to one end of the liquid air pump (43); the other end of the liquid air pump (43) is connected to the second cold medium input end of the second plate-fin heat exchanger (22); the second cold medium output end of the second plate-fin heat exchanger (22) is connected to the second cold medium input end of the first plate-fin heat exchanger (21); and the second cold medium output end of the first plate-fin heat exchanger (21) is connected to the gas input end of the expansion power generation mechanism (5).

8. A cold energy recovery system for a liquefied air energy storage system according to claim 7, characterized in that: The power generation component includes a first generator (51) and a second generator (52), and the expansion component includes a first power generation expander (53) for driving the first generator (51) to generate electricity, and a second power generation expander (54) for driving the second generator (52) to generate electricity. One end of the first power generation expander (53) is connected to the second cold medium output end of the first plate-fin heat exchanger (21), and the other end of the first power generation expander (53) is connected to the third cold medium input end of the first plate-fin heat exchanger (21). The third cold medium output end of the first plate-fin heat exchanger (21) is connected to one end of the second power generation expander (54), and the other end of the second power generation expander (54) is connected to the atmosphere, or connected to the gas input end of the air processing mechanism (1).

9. A cold energy recovery system for a liquefied air energy storage system according to claim 8, characterized in that: A first heater (55) is provided between one end of the first power generation expander (53) and the second cold medium output end of the first plate-fin heat exchanger (21), and a second heater (56) is provided between the third cold medium output end of the first plate-fin heat exchanger (21) and one end of the second power generation expander (54).

10. A control method for a cold recovery system of a liquefied air energy storage system, characterized in that: Applied to a cold recovery system of a liquefied air energy storage system as claimed in any one of claims 1 to 9, the control method comprises: Determine a current power consumption state, wherein the current power consumption state includes at least a power consumption valley and a power consumption peak; If the current power consumption state is a low power consumption state, the liquid level data of the storage mechanism (4) is obtained to determine whether the liquid level data is less than a predetermined preset liquid level threshold value; if it is not less than the predetermined preset liquid level threshold value, the determination is continued; if it is less than the predetermined preset liquid level threshold value, the expansion power generation mechanism (5) is turned off, and the air processing mechanism (1), the expansion refrigeration mechanism (3), the heat exchange mechanism (2) and the storage mechanism (4) are turned on, so that the storage mechanism (4) stores liquid air until the liquid level data is greater than or equal to the predetermined preset liquid level threshold value; If the current electricity consumption status is at a peak, the expansion refrigeration mechanism (3) is turned off, and the air processing mechanism (1), the expansion power generation mechanism (5), the heat exchange mechanism (2) and the storage mechanism (4) are turned on to enable the expansion power generation mechanism (5) to generate electricity.

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