Liquid air energy storage system for solar stepwise utilization and operation method thereof

Abstract

The application discloses a kind of solar energy cascade utilization liquid air energy storage system and its operating method, the system includes liquid air energy storage system, photo-thermal power generation system and organic rankine cycle power generation system.In the low valley of electricity and light, photo-thermal power generation system generates electric energy, part is used to drive liquid air energy storage subsystem for supply load.The system uses air liquefaction and expansion cycle to realize energy storage, and converts excess electric energy into liquid air storage.In the peak of electricity, the system releases energy, and produces electric energy by gasification and expansion liquid working medium, and uses photo-thermal heat in the form of series, parallel heat exchange to heat working medium, realizes energy cascade utilization, solves the problem of low efficiency of expander when liquid air releases energy.The system can make full use of the peak shaving potential of liquid air energy storage, organically combines the thermal energy and electric energy of photo-thermal system, is conducive to improving overall energy conversion efficiency, realizes all-weather renewable energy utilization.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of solar power generation and liquid air energy storage, in particular to a solar energy cascade utilization liquid air energy storage system and a method for operating the same. BACKGROUND

[0002] In the context of global energy transformation today, solar thermal power generation technology, as an important clean energy technology, has attracted much attention. It converts light energy directly into electricity using solar energy, which is pollution-free, renewable, and other advantages, making it a popular choice in the field of clean energy. However, due to factors such as weather changes, the output power of the solar thermal power generation system is intermittent and volatile, which poses certain challenges to the stable operation of the power system. Liquid air energy storage (LAES) technology uses electricity to compress and liquefy air for storage, and releases air when needed to generate electricity through an expander. Compared with traditional battery energy storage technology, it has the advantages of high energy storage density, long service life, and environmental friendliness, and is considered a new type of energy storage technology with great potential. However, the liquefied air energy storage system is limited by the Carnot cycle efficiency and its own need for both cooling and heating, and the low temperature of the working medium in the expansion work stage results in low work efficiency. In this context, the combination of solar thermal power generation systems and liquid air energy storage technology is expected to improve energy storage efficiency, utilization efficiency of solar thermal power generation systems, and stability of the power system, and can make full use of the electrical and thermal energy of solar thermal power generation to offset the imbalance between power supply and demand. However, the existing patent coupling of solar thermal liquid air energy storage system has many deficiencies in energy cascade utilization and waste heat utilization, and the energy utilization form of the existing patent for coupling solar thermal liquid air energy storage system is single and has deficiencies. SUMMARY

[0003] In order to solve the problems existing in the prior art, the purpose of the present application is to provide a solar energy cascade utilization liquid air energy storage system and a method for operating the same, which can fully utilize the peak shaving potential of liquid air energy storage, organically combine the thermal and electrical energy of the solar thermal system, and improve the overall energy conversion efficiency and realize all-weather renewable energy utilization.

[0004] In order to achieve the above purpose, the technical scheme adopted by the present application is as follows:

[0005] A solar energy cascade utilization liquid air energy storage system, comprising a liquid air energy storage subsystem, a solar thermal power generation subsystem, and an organic Rankine cycle power generation subsystem, wherein:

[0006] The liquid air energy storage subsystem comprises a liquefaction energy storage unit and an expansion energy release unit; wherein the liquefaction energy storage unit comprises a multi-stage compressor, an air circulation heat end heat exchanger connected after each stage of compressor, a heat storage tank 24, a cold storage tank 25, a cold storage tank outlet pump 37, a cold storage tank outlet valve 36, a cold accumulation circulation cold end heat exchanger 7, a cold accumulation circulation low-temperature tank 27, a cold accumulation circulation first control valve 28, a cold accumulation circulation cold pump 44, a cold accumulation circulation normal-temperature tank 26, a low-temperature turbine 8, a throttle valve 9, a gas-liquid separator 10, and a liquid storage tank 11; the working medium is from the ambient air, the air working medium passes through each stage of compressor and the corresponding air circulation heat end heat exchanger, enters the cold accumulation circulation cold end heat exchanger 7, is cooled to a liquid temperature, and then enters the low-temperature turbine 8 to expand to the ambient pressure, the air is throttled by the throttle valve 9 and becomes liquid by the gas-liquid separator 10, and is stored in the liquid storage tank 11; at the same time, the hot oil is stored in the cold storage tank 25 as a heat exchange medium, the cold storage tank 25 outlet is connected with the cold storage tank outlet pump 37 and the cold storage tank outlet valve 36, the cold storage tank outlet valve 36 is connected with the heat exchange inlets of the air circulation heat end first heat exchanger 2, the air circulation heat end second heat exchanger 4 and the air circulation heat end third heat exchanger 6 respectively, and the hot oil after heat exchange enters the heat storage tank 24; at the same time, the propane is stored in the cold accumulation circulation low-temperature tank 27 as a cold accumulation circulation medium, the cold accumulation circulation low-temperature tank 27 is connected with the cold circulation first control valve 28 and the cold accumulation circulation cold pump 44, the cold accumulation medium is delivered to the cold accumulation circulation cold end heat exchanger 7 inlet by the cold accumulation circulation cold pump 44, and the cold accumulation circulation cold end heat exchanger 7 outlet is connected with the cold accumulation circulation normal-temperature tank 26;

[0007] The expansion energy release unit comprises a liquid storage tank 11, a liquid storage tank outlet valve 46, a low-temperature pressurizing pump 12, a cold accumulation cycle normal-temperature end heat exchanger 13, a cold accumulation cycle low-temperature tank 27, a cold accumulation cycle normal-temperature tank 26, a cold accumulation cycle first control valve 28, a cold accumulation cycle second control valve 47, a cold accumulation cycle normal-temperature pump 45, a preheater 23, a heat storage tank 24, a cold storage tank 25, a heat storage tank outlet pump 39, a heat storage tank outlet valve 38, an air circulation cold end first heat exchanger 14, a first-stage air expander 15, an air circulation cold end second heat exchanger 16, a second-stage air expander 17, an air circulation cold end third heat exchanger 18, a light-heat first heat exchanger 19, a third-stage air expander 20, a light-heat second heat exchanger 21, and a fourth-stage air expander 22; normal-pressure liquid air is stored in the liquid storage tank 11 as an energy storage medium, the liquid storage tank 11 is connected with the liquid storage tank outlet valve 46 and the low-temperature pressurizing pump 12, the low-temperature pressurizing pump 12 delivers the air medium to the cold accumulation cycle normal-temperature end heat exchanger 13, the air medium is heated and then enters the preheater 23, the preheater 23 is connected with the air circulation cold end first heat exchanger 14, the heated air medium enters the first-stage air expander 15 to output electric energy, the first-stage air expander 15 is connected with the air circulation cold end second heat exchanger 16, the heated air medium enters the second-stage air expander 17, and then the air is sequentially heated in the air circulation cold end third heat exchanger 18 and the light-heat first heat exchanger 19, the heated air medium enters the third-stage air expander 20, the outlet air is heated in the light-heat second heat exchanger 21, the heated air medium enters the fourth-stage air expander 22, and the fourth-stage air expander 22 is connected with the preheater 23; meanwhile, the hot oil storing multi-stage compressed heat energy enters the heat storage tank outlet pump 39 and the heat storage tank outlet valve 38 from the heat storage tank 24, the hot oil as a heat supply medium enters the heat exchange inlets of the air circulation cold end first heat exchanger 14, the air circulation cold end second heat exchanger 16 and the air circulation cold end third heat exchanger 18, and the heated hot oil enters the cold storage tank 25; meanwhile, the working medium propane in the cold accumulation cycle normal-temperature tank 26 enters the cold accumulation cycle second control valve 47 and the cold accumulation cycle normal-temperature pump 45, is then heated in the cold accumulation cycle normal-temperature end heat exchanger 13, and finally the low-temperature propane is stored in the cold accumulation cycle low-temperature tank 27.

[0008] The photo-thermal power generation system comprises a solar heat collector 31, a hot tank 29, a cold tank 30, a 1# hot tank outlet pump 40, a 2# hot tank outlet pump 42, a 1# hot tank outlet valve 41, a 2# hot tank outlet valve 43, a photo-thermal first heat exchanger 19, a photo-thermal second heat exchanger 21 and an evaporator 34; the solar heat collector 31 converts solar energy into heat energy by collecting sunlight and transmits the heat energy to a solar heat storage medium in the hot tank 29; the hot tank 29 has two outlets: one is connected to the 1# hot tank outlet pump 40 and the 1# hot tank outlet valve 41, and the 1# hot tank outlet valve 41 is connected to the photo-thermal first heat exchanger 19 and the photo-thermal second heat exchanger 21 respectively; the solar heat storage medium is collected at the outlets of the photo-thermal first heat exchanger 19 and the photo-thermal second heat exchanger 21 and then enters the evaporator 34; the other is connected to the 2# hot tank outlet pump 42 and the 2# hot tank outlet valve 43, and the solar heat storage medium directly enters the evaporator 34; the outlet of the heat exchange end of the evaporator 34 is connected to the cold tank 30.

[0009] The organic Rankine cycle power generation system comprises the evaporator 34, a turbine 33, a condenser 32 and a pump 35; the heat exchange end of the evaporator 34 is connected to the outlets of the photo-thermal first heat exchanger 19 and the photo-thermal second heat exchanger 21, and the evaporator 34 is heated by the solar heat storage medium; the outlet of the evaporator 34 is connected to the turbine 33; the working medium enters the condenser 32 after expansion and work; the outlet of the condenser 32 is connected to the pump 35; and the working medium pressurized by the pump 35 enters the inlet of the evaporator 34.

[0010] Further, the heat energy of the solar heat storage medium in the photo-thermal power generation system is utilized in stages: firstly, the solar heat storage medium collects heat in the hot tank 29; then the solar heat storage medium enters the photo-thermal first heat exchanger 19 and the photo-thermal second heat exchanger 21 to transfer part of the heat energy to the air medium; then the solar heat storage medium enters the evaporator 34 to exchange heat and drive the turbine 33 of the organic Rankine cycle power generation system; then the solar heat storage medium enters the cold tank 30 for storage; and finally the solar heat storage medium returns to the solar heat collector 31 to collect solar heat again, and the process is repeated.

[0011] Further, in the first stage of expansion of the expansion and energy release unit, the working medium is heated by the preheater 23 and the air circulation cold end first heat exchanger 14 and then enters the first stage air expander 15 with low power; the operating temperature range of the first stage air expander 15 is 370-500℃; in the second stage of expansion of the expansion and energy release unit, the working medium is heated by the air circulation cold end second heat exchanger 16 and then enters the second stage air expander 17; the operating temperature range of the second stage air expander 17 is 370-500℃; in the third stage of expansion of the expansion and energy release unit, the air circulation cold end third heat exchanger 18 and the photo-thermal first heat exchanger 19 form a parallel heating unit to greatly increase the temperature of the working medium, and then the working medium enters the third stage air expander 20; the operating temperature range of the third stage air expander 20 is 450-900℃; in the fourth stage of expansion of the expansion and energy release unit, the working medium is heated by the photo-thermal second heat exchanger 21 and then enters the fourth stage air expander 22; the operating temperature range of the fourth stage air expander 22 is 450-900℃.

[0012] Further, the first-stage air expander 15, the second-stage air expander 17, the third-stage air expander 20, and the fourth-stage air expander 22 of the expansion and energy release unit are coaxially connected.

[0013] Further, the liquid air energy storage subsystem is composed of at least three compressors. When the liquid air energy storage subsystem is composed of three compressors, i.e., the first-stage compressor 1, the second-stage compressor 3, and the third-stage compressor 5, a centrifugal compressor is used, and the comprehensive pressure ratio range of the inlet and outlet is 8-10. Corresponding air circulation heat end heat exchangers, i.e., the air circulation heat end first heat exchanger 2, the air circulation heat end second heat exchanger 4, and the air circulation heat end third heat exchanger 6.

[0014] Further, the gas-liquid separator 10 is a vertical gravity type separator. The separated liquid air enters the liquid storage tank 11, and the separated gaseous air enters the first-stage compressor.

[0015] The operation method of the liquid air energy storage system for solar energy cascade utilization has the following characteristics: the liquid air energy storage subsystem has two operation stages.

[0016] 1) Energy storage stage: the expansion and energy release unit temporarily stops working. Most of the electric energy output by the photo-thermal power generation subsystem is used as the power source of the liquefied energy storage unit. The excess electric energy is stored in the liquid storage tank 11 in the form of liquid air. Specifically, the liquid storage tank outlet valve 46 is closed, the low-temperature pressurizing pump 12 is stopped, the cold storage tank outlet valve 36 is opened, the cold storage tank outlet pump 37 is started, the hot storage tank outlet valve 38 is closed, the cold storage circulation first control valve 28 is opened, the cold storage circulation cold pump 44 is started, the cold storage circulation second control valve 47 is closed, and the multi-stage compressor is started. The ambient air enters the multi-stage compressor, is compressed, and then enters the corresponding air circulation heat end heat exchanger for cooling. The high-pressure air enters the cold storage circulation cold end heat exchanger 7, is cooled to a liquid temperature, and then enters the low-temperature turbine 8 to expand to the ambient pressure. The air is throttled by the throttle valve 9 and the gas-liquid separator 10 to become liquid, and is finally stored in the liquid storage tank 11. The heat exchange medium in the cold storage tank 25 is transported to the multi-stage air circulation heat end heat exchanger by the cold storage tank outlet pump 37, cools the compressed high-temperature air, and then enters the hot storage tank 24 for storage. The low-temperature propane in the cold storage circulation low-temperature tank 27 is transported to the cold storage circulation cold end heat exchanger 7 by the cold storage circulation cold pump 44, cools the air medium, and then enters the cold storage circulation normal-temperature tank 26 for storage.

[0017] 2) Discharge phase, the liquefied energy storage unit temporarily stops working, and the liquid air is expanded to do work and output electric energy after being pressurized and heated. Specifically, the liquid storage tank outlet valve 46 is opened, the low-temperature pressurized pump 12 is started, the cold storage cycle first control valve 28 is closed, the cold storage cycle second control valve 47 is opened, the cold storage cycle normal-temperature pump 45 is operated, the cold storage tank outlet valve 36 is closed, the heat storage tank outlet valve 38 is opened, the heat storage tank outlet pump 39 is operated, the first-stage air expander 15, the second-stage air expander 17, the third-stage air expander 20 and the fourth-stage air expander 22 are put into operation; the liquid air is transported into the cold storage cycle normal-temperature end heat exchanger 13 of the cold storage cycle by the low-temperature pressurized pump 12, and the cold energy is stored to the cold storage cycle, and then the air working medium is preheated by the preheater 23 and the air cycle cold end first heat exchanger 14 and the preheater, enters the first-stage air expander 15 to be expanded for the first time, generates electric energy and outputs it, is heated by the air cycle cold end second heat exchanger 16, is expanded for the second time by the second-stage air expander 17, is heated by the air cycle cold end third heat exchanger 18 and the light-heat first heat exchanger 19 supplied by the light-heat system to ensure a higher working medium temperature, enters the third-stage air expander 20 to be expanded for the third time, is heated by the light-heat second heat exchanger 21 alone, enters the fourth-stage air expander 22 to be expanded for the fourth time, and the outlet air enters the preheater 23 to preheat the air; the propane in the cold storage cycle normal-temperature tank 26 is transported to the cold storage cycle normal-temperature end heat exchanger 13 by the cold storage cycle normal-temperature pump 45, and the cold energy of the propane carrying the liquid air after heat exchange is stored in the cold storage cycle low-temperature tank 27; the hot oil in the heat storage tank 24 is transported to the air cycle cold end first heat exchanger 14, the air cycle cold end second heat exchanger 16 and the air cycle cold end third heat exchanger 18 by the heat storage tank outlet pump 39, and the hot oil is stored in the cold storage tank 25 after heating the air medium.

[0018] The light-heat power generation system and the organic Rankine cycle power generation system have two operation phases:

[0019] 1) Energy storage phase, the solar heat collector 31 generates high-temperature heat energy by collecting solar radiation, heats the solar energy storage medium in the hot tank 29, the solar energy storage medium directly supplies the organic Rankine cycle power generation system to do work and generate electricity, most of the output electric energy is used as the power source of the liquefied energy storage unit, and the liquefied air is stored; Specifically, the 2# hot tank outlet valve 43 is opened, the 1# hot tank outlet valve 41 is closed, the 2# hot tank outlet pump 42 is operated, and the steam turbine 33 is put into operation; the solar energy storage medium in the hot tank 29 is transported to the condenser 32 of the organic Rankine cycle power generation system by the 2# hot tank outlet pump 42, the solar energy storage medium heats the organic Rankine cycle working medium, the organic Rankine cycle working medium is expanded by the steam turbine 33 to generate electricity, most of the output electric energy is supplied to the multi-stage compressor, the liquefied air is stored, and a small part of the electric energy is supplied to the user;

[0020] 2) discharging phase, the solar heat storage medium first releases heat to the air medium in the expansion and discharging unit of the liquid air energy storage subsystem, and then the organic Rankine cycle power generation subsystem is powered to generate electricity; specifically, the 1# hot tank outlet valve 41 is opened, the 2# hot tank outlet valve 43 is closed, the 1# hot tank outlet pump 40 is operated, the light-heat first heat exchanger 19 and the light-heat second heat exchanger 21 are put into operation, and the steam turbine 33 is put into operation; the solar heat storage medium in the hot tank 29 is transported to the light-heat first heat exchanger 19 and the light-heat second heat exchanger 21 by the 1# hot tank outlet pump 40, the solar heat storage medium heats the air medium, and then enters the condenser 32 of the organic Rankine cycle power generation subsystem to exchange heat, and finally enters the cold tank 30.

[0021] Compared with the prior art, the present application has the following advantages:

[0022] (1) The multi-stage heating unit adopted in the discharging phase of the liquid air energy storage subsystem, the first two stages are connected with the heat exchange circulating unit, and the temperature is gradually increased to avoid the reduction of heat exchange efficiency caused by the terminal difference; the last two stages are connected in series and parallel with the light-heat heat exchanger, which greatly improves the inlet air temperature of the steam turbine, which is beneficial to the efficient operation of the air expander and improves the power generation efficiency, and the technical and economic advantages are more prominent;

[0023] (2) The light-heat power generation subsystem is integrated with each part, which can realize the cascade utilization of heat energy, and the multi-level energy conversion mode improves the energy conversion efficiency of the whole system and ensures the efficient utilization of energy;

[0024] (3) The light-heat power generation subsystem provides a higher expansion temperature for the liquid air energy storage subsystem, and the organic Rankine cycle power generation subsystem utilizes the remaining heat energy to generate more storage power, effectively improving the cycle efficiency of the energy storage system. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 It is a schematic diagram of a liquid air energy storage system for solar cascade utilization. DETAILED DESCRIPTION

[0026] The preferred embodiments described herein are only used to illustrate and explain the present application, and are not used to limit the present application.

[0027] As Figure 1 shown, the present application provides a liquid air energy storage system for solar cascade utilization and a method for operating the same, the system comprising a liquid air energy storage subsystem, a light-heat power generation subsystem, and an organic Rankine cycle power generation subsystem, wherein:

[0028] The liquid air energy storage subsystem comprises a liquefied energy storage unit and an expansion energy release unit; wherein the liquefied energy storage unit comprises a primary compressor 1, an air circulation hot end first heat exchanger 2, a secondary compressor 3, an air circulation hot end second heat exchanger 4, a tertiary compressor 5, an air circulation hot end third heat exchanger 6, a heat storage tank 24, a cold storage tank 25, a cold storage tank outlet pump 37, a cold storage tank outlet valve 36, a cold storage circulation cold end heat exchanger 7, a cold storage circulation low-temperature tank 27, a cold storage circulation first control valve 28, a cold storage circulation cold pump 44, a cold storage circulation normal-temperature tank 26, a low-temperature turbine 8, a throttle valve 9, a gas-liquid separator 10, and a liquid storage tank 11; the working medium is from ambient air, the primary compressor 1 outlet is connected with the air circulation hot end first heat exchanger 2, the air working medium after heat exchange enters the secondary compressor 3, the secondary compressor 3 outlet is connected with the air circulation hot end second heat exchanger 4, the air circulation hot end second heat exchanger 4 outlet is connected with the air circulation hot end third heat exchanger 6 through the tertiary compressor 5, and then the air working medium enters the cold storage circulation cold end heat exchanger 7 to be cooled to a liquid temperature, and then enters the low-temperature turbine 8 to be expanded to an ambient pressure, the air is throttled through the throttle valve 9 and becomes liquid through the gas-liquid separator 10, and is stored in the liquid storage tank 11; meanwhile, hot oil is stored in the cold storage tank 25 as a heat exchange medium, the cold storage tank 25 outlet is connected with the cold storage tank outlet pump 37 and the cold storage tank outlet valve 36, the cold storage tank outlet valve 36 is respectively connected with heat exchange inlets of the air circulation hot end first heat exchanger 2, the air circulation hot end second heat exchanger 4 and the air circulation hot end third heat exchanger 6, and the hot oil after heat exchange enters the heat storage tank 24; meanwhile, propane is stored in the cold storage circulation low-temperature tank 27 as a cold storage circulation medium, the cold storage circulation low-temperature tank 27 is connected with the cold storage circulation first control valve 28 and the cold storage circulation cold pump 44, the cold storage medium is delivered to the cold storage circulation cold end heat exchanger 7 inlet by the cold storage circulation cold pump 44, and the cold storage circulation cold end heat exchanger 7 outlet is connected with the cold storage circulation normal-temperature tank 26.

[0029] The expansion energy release unit comprises a liquid storage tank 11, a liquid storage tank outlet valve 46, a low-temperature pressurizing pump 12, a cold accumulation cycle normal-temperature end heat exchanger 13, a cold accumulation cycle low-temperature tank 27, a cold accumulation cycle normal-temperature tank 26, a cold accumulation cycle first control valve 28, a cold accumulation cycle second control valve 47, a cold accumulation cycle normal-temperature pump 45, a preheater 23, a heat storage tank 24, a cold storage tank 25, a heat storage tank outlet pump 39, a heat storage tank outlet valve 38, an air circulation cold end first heat exchanger 14, a first-stage air expander 15, an air circulation cold end second heat exchanger 16, a second-stage air expander 17, an air circulation cold end third heat exchanger 18, a light-heat first heat exchanger 19, a third-stage air expander 20, a light-heat second heat exchanger 21, and a fourth-stage air expander 22; normal-pressure liquid air is stored in the liquid storage tank 11 as an energy storage medium, the liquid storage tank 11 is connected with the liquid storage tank outlet valve 46 and the low-temperature pressurizing pump 12, the low-temperature pressurizing pump 12 delivers the air medium to the cold accumulation cycle normal-temperature end heat exchanger 13, the air medium is heated and then enters the preheater 23, the preheater 23 is connected with the air circulation cold end first heat exchanger 14, the heated air medium enters the first-stage air expander 15 to output electric energy, the first-stage air expander 15 is connected with the air circulation cold end second heat exchanger 16, the heated air medium enters the second-stage air expander 17, and then the air is sequentially heated in the air circulation cold end third heat exchanger 18 and the light-heat first heat exchanger 19, the heated air medium enters the third-stage air expander 20, the outlet air is heated in the light-heat second heat exchanger 21, the heated air medium enters the fourth-stage air expander 22, and the fourth-stage air expander 22 is connected with the preheater 23; meanwhile, the hot oil storing multi-stage compressed heat energy enters the heat storage tank outlet pump 39 and the heat storage tank outlet valve 38 from the heat storage tank 24, the hot oil as a heat supply medium enters the heat exchange inlets of the air circulation cold end first heat exchanger 14, the air circulation cold end second heat exchanger 16 and the air circulation cold end third heat exchanger 18, and the heated hot oil enters the cold storage tank 25; meanwhile, the working medium propane in the cold accumulation cycle normal-temperature tank 26 enters the cold accumulation cycle second control valve 47 and the cold accumulation cycle normal-temperature pump 45, is then heated in the cold accumulation cycle normal-temperature end heat exchanger 13, and finally the low-temperature propane is stored in the cold accumulation cycle low-temperature tank 27.

[0030] The photo-thermal power generation system comprises a solar heat collector 31, a hot tank 29, a cold tank 30, a 1# hot tank outlet pump 40, a 2# hot tank outlet pump 42, a 1# hot tank outlet valve 41, a 2# hot tank outlet valve 43, a photo-thermal first heat exchanger 19, a photo-thermal second heat exchanger 21 and an evaporator 34; the entire energy storage power generation system can collect energy by charging the surplus power generated by the solar photo-thermal, and the power generation process can use the heat energy of the photo-thermal power generation system to provide the temperature of the expanded air, thereby increasing the working efficiency of the air expander; the solar heat collector 31 converts solar energy into heat energy by collecting sunlight and transmits the heat energy to the solar heat storage medium in the hot tank 29; the hot tank 29 has two outlets: one is connected to the 1# hot tank outlet pump 40 and the 1# hot tank outlet valve 41, and the 1# hot tank outlet valve 41 is connected to the photo-thermal first heat exchanger 19 and the photo-thermal second heat exchanger 21, respectively; the solar heat storage medium is collected at the outlets of the photo-thermal first heat exchanger 19 and the photo-thermal second heat exchanger 21 and then enters the evaporator 34; the other is connected to the 2# hot tank outlet pump 42 and the 2# hot tank outlet valve 43, and the solar heat storage medium directly enters the evaporator 34; the heat exchange end outlet of the evaporator 34 is connected to the cold tank 30.

[0031] The organic Rankine cycle power generation system comprises an evaporator 34, a turbine 33, a condenser 32 and a pump 35; the heat exchange end of the evaporator 34 is connected to the outlets of the photo-thermal first heat exchanger 19 and the photo-thermal second heat exchanger 21, and the working medium is heated by the solar heat storage medium; the outlet of the evaporator 34 is connected to the turbine 33, and the working medium is expanded to work after entering the condenser 32; the outlet of the condenser 32 is connected to the pump 35, and the working medium pressurized by the pump 35 enters the inlet of the evaporator 34.

[0032] Further, the heat energy of the solar heat storage medium in the photo-thermal power generation system is utilized in stages, which increases the working efficiency of the energy release stage and ensures the safe and stable operation of the unit; first, the solar heat storage medium collects heat in the hot tank 29, then the solar heat storage medium enters the photo-thermal first heat exchanger 19 and the photo-thermal second heat exchanger 21 to transfer part of the heat energy to the air medium, then enters the evaporator 34 for heat exchange to drive the turbine 33 of the organic Rankine cycle power generation system, then the solar heat storage medium enters the cold tank 30 for storage, and finally returns to the solar heat collector 31 to collect solar heat again, and the process is repeated.

[0033] Further, the expansion energy release unit uses the small power air expanders of the first two stages to gradually increase the expansion temperature, and the last two stages use the surplus heat energy of the solar thermal power generation system to increase the expansion temperature, greatly increasing the work output of the expansion potential stage. In the first stage expansion, the working medium is heated by the preheater 23 and the air circulation cold end first heat exchanger 14, and then enters the small power first stage air expander 15, with an operating temperature range of 370-500°C. In the second stage expansion of the expansion energy release unit, the working medium is heated by the air circulation cold end second heat exchanger 16, and then enters the second stage air expander 17, with an operating temperature range of 370-500°C. In the third stage expansion of the expansion energy release unit, the air circulation cold end third heat exchanger 18 and the solar thermal first heat exchanger 19 form a parallel heating unit, and after the temperature of the working medium is greatly increased, it enters the third stage air expander 20, with an operating temperature range of 450-900°C. In the fourth stage expansion of the expansion energy release unit, the working medium enters the solar thermal second heat exchanger 21 after being heated, and then enters the fourth stage air expander 22, with an operating temperature range of 450-900°C. The first two stages of air expanders have lower power and lower operating temperature range, and the outlet air medium temperature still retains a lot of excess heat, which can avoid the end difference loss caused by excessive heat transfer temperature difference when entering the solar thermal first heat exchanger 19 and the solar thermal second heat exchanger 21. At the same time, the higher temperature air medium enters the larger power expanders of the last two stages to do work, thereby outputting electric energy. Through heat exchange, a higher operating temperature is obtained, which is conducive to the efficient operation of the third stage air expander 20 and the fourth stage air expander 22, improves the power generation efficiency, and improves the technical and economic performance.

[0034] Further, the first stage air expander 15, the second stage air expander 17, the third stage air expander 20 and the fourth stage air expander 22 of the expansion energy release unit are coaxially connected, and use high pressure and high temperature air expansion to do work and output electric energy.

[0035] Further, the liquid air energy storage subsystem is composed of at least three stages of compressors, i.e. the first stage compressor 1, the second stage compressor 3 and the third stage compressor 5, which are centrifugal compressors with an integrated pressure ratio range of 8-10. Continuous three-stage or more compression energy storage can provide higher compression efficiency and more stable performance, significantly reducing energy loss and temperature rise during the compression process. At the same time, the centrifugal compressor has the advantages of simple structure, convenient maintenance, reliable operation, strong ability to handle large flow of gas, and is suitable for large-scale energy storage demand, which helps to improve the overall energy efficiency and economic performance of the system.

[0036] Further, the gas-liquid separator 10 adopts a vertical gravity type separator, which can efficiently realize liquid-gas separation, ensure the purity of liquid air, improve the cold storage and energy storage effect of the system, and store the separated liquid air in the liquid storage tank 11. The separated gaseous air enters the primary compressor 1, recovers and recompresses the gaseous air, reduces energy waste, and improves the circulation efficiency and economy of the entire system.

[0037] The operation method of the liquid air energy storage system for solar energy cascade utilization has two operation stages of the liquid air energy storage subsystem:

[0038] 1) Energy storage stage, the expansion and energy release unit temporarily stops working, most of the electric energy output by the photo-thermal power generation subsystem is used as the power source of the liquefied energy storage unit, and the excess electric energy is stored in the liquid storage tank 11 in the form of liquid air; specifically, the liquid storage tank outlet valve 46 is closed, the low-temperature pressurizing pump 12 is stopped, the cold storage tank outlet valve 36 is opened, the cold storage tank outlet pump 37 is started, the heat storage tank outlet valve 38 is closed, the first control valve 28 of the cold storage cycle is opened, the cold storage cycle cold pump 44 is started, the second control valve 47 of the cold storage cycle is closed, the primary compressor 1, the secondary compressor 3 and the tertiary compressor 5 are put into operation; the ambient air enters the primary compressor 1, is compressed and then enters the air circulation heat end first heat exchanger 2, enters the secondary compressor 3 after the air circulation heat end first heat exchanger 2 reduces the air temperature, the compressed air enters the air circulation heat end second heat exchanger 4 and is cooled, then enters the tertiary compressor 5 and is cooled by the air circulation heat end third heat exchanger 6, the high-pressure air enters the cold storage cycle cold end heat exchanger 7 and is cooled to a liquid temperature, and then enters the low-temperature turbine 8 and expands to the ambient pressure, the air is throttled by the throttle valve 9 and becomes liquid by the gas-liquid separator 10, and finally is stored in the liquid storage tank 11; the heat exchange medium in the cold storage tank 25 is transported to the air circulation heat end first heat exchanger 2, the air circulation heat end second heat exchanger 4 and the air circulation heat end third heat exchanger 6 by the cold storage tank outlet pump 37, cools the compressed high-temperature air, and then the heat exchange medium enters the heat storage tank 24 for storage; the low-temperature propane in the cold storage cycle low-temperature tank 27 is transported to the cold storage cycle cold end heat exchanger 7 by the cold storage cycle cold pump 44, cools the air medium and then enters the cold storage cycle normal-temperature tank 26 for storage;

[0039] 2) Discharge phase, the liquefied energy storage unit temporarily stops working, and the liquid air is expanded to do work and output electric energy after being pressurized and heated. Specifically, the liquid storage tank outlet valve 46 is opened, the low-temperature pressurized pump 12 is started, the cold storage cycle first control valve 28 is closed, the cold storage cycle second control valve 47 is opened, the cold storage cycle normal-temperature pump 45 is operated, the cold storage tank outlet valve 36 is closed, the heat storage tank outlet valve 38 is opened, the heat storage tank outlet pump 39 is operated, the first-stage air expander 15, the second-stage air expander 17, the third-stage air expander 20 and the fourth-stage air expander 22 are put into operation; the liquid air is transported into the cold storage cycle normal-temperature end heat exchanger 13 of the cold storage cycle by the low-temperature pressurized pump 12, and the cold energy is stored to the cold storage cycle, and then the air working medium is preheated by the preheater 23 and the air cycle cold end first heat exchanger 14 and the air cycle cold end second heat exchanger 16, and then enters the first-stage air expander 15 to be expanded for the first time to generate electric energy, and the electric energy is outputted outward, and after being supplemented with heat by the air cycle cold end second heat exchanger 16, the air is expanded for the second time by the second-stage air expander 17, and then the air is heated by the air cycle cold end third heat exchanger 18 and the light-heat first heat exchanger 19 supplied by the light-heat system to ensure a higher working medium temperature, and the air enters the third-stage air expander 20 to be expanded for the third time to do work, and then after being heated by the light-heat second heat exchanger 21 alone, the air enters the fourth-stage air expander 22 to be expanded for the fourth time to do work, and the outlet air enters the preheater 23 to preheat the air as a working medium; the propane in the cold storage cycle normal-temperature tank 26 is transported to the cold storage cycle normal-temperature end heat exchanger 13 by the cold storage cycle normal-temperature pump 45, and the cold energy of the propane carrying the liquid air after heat exchange is stored in the cold storage cycle low-temperature tank 27; the hot oil in the heat storage tank 24 is transported to the air cycle cold end first heat exchanger 14, the air cycle cold end second heat exchanger 16 and the air cycle cold end third heat exchanger 18 by the heat storage tank outlet pump 39, and the hot oil is stored in the cold storage tank 25 after heating the air medium.

[0040] The light-heat power generation system and the organic Rankine cycle power generation system have two operation phases:

[0041] 1) Energy storage phase, the solar heat collector 31 generates high-temperature heat energy by collecting solar radiation, heats the solar heat storage medium in the heat tank 29, the solar heat storage medium directly supplies the organic Rankine cycle power generation system to do work and generate electricity, most of the output electric energy is used as the power source of the liquefied energy storage unit, and the liquefied air is stored; Specifically, the 2# heat tank outlet valve 43 is opened, the 1# heat tank outlet valve 41 is closed, the 2# heat tank outlet pump 42 is operated, and the steam turbine 33 is put into operation; the solar heat storage medium in the heat tank 29 is transported to the condenser 32 of the organic Rankine cycle power generation system by the 2# heat tank outlet pump 42, the solar heat storage medium heats the organic Rankine cycle working medium, the organic Rankine cycle working medium is expanded by the steam turbine 33 to generate electricity, most of the output electric energy is supplied to the primary compressor 1, the secondary compressor 3 and the tertiary compressor 5, the liquefied air is stored, and a small part of the electric energy is supplied to the user;

[0042] 2) the energy release stage, the solar heat storage medium first releases heat to the air medium in the expansion energy release unit of the liquid air energy storage subsystem, and then the organic Rankine cycle power generation subsystem generates power; specifically, the 1# hot tank outlet valve 41 is opened, the 2# hot tank outlet valve 43 is closed, the 1# hot tank outlet pump 40 is operated, the light-heat first heat exchanger 19 and the light-heat second heat exchanger 21 are put into operation, and the steam turbine 33 is put into operation; the solar heat storage medium in the hot tank 29 is transported to the light-heat first heat exchanger 19 and the light-heat second heat exchanger 21 by the 1# hot tank outlet pump 40, the solar heat storage medium heats the air medium, and then enters the condenser 32 of the organic Rankine cycle power generation subsystem to exchange heat, and finally enters the cold tank 30.

Claims

1. A liquid air energy storage system for solar step- utilization, characterized by: The system comprises a liquid air energy storage subsystem, a photo-thermal power generation subsystem, and an organic Rankine cycle power generation subsystem. The liquid air energy storage subsystem comprises a liquefaction energy storage unit and an expansion energy release unit; the liquefaction energy storage unit comprises a multi-stage compressor, an air circulation heat end heat exchanger connected after each stage of the compressor, a heat storage tank (24), a cold storage tank (25), a cold storage tank outlet pump (37), a cold storage tank outlet valve (36), a cold storage circulation cold end heat exchanger (7), a cold storage circulation low-temperature tank (27), a cold storage circulation first control valve (28), a cold storage circulation cold pump (44), a cold storage circulation normal-temperature tank (26), a low-temperature turbine (8), a throttle valve (9), a gas-liquid separator (10), and a liquid storage tank (11); the working medium is from ambient air, the air working medium passes through each stage of the compressor and the corresponding air circulation heat end heat exchanger, enters the cold storage circulation cold end heat exchanger (7), is cooled to a liquid temperature, enters the low-temperature turbine (8), expands to the ambient pressure, is throttled by the throttle valve (9), is separated into a liquid by the gas-liquid separator (10), and is stored in the liquid storage tank (11); meanwhile, hot oil is stored in the cold storage tank (25) as a heat exchange medium, the cold storage tank (25) outlet is connected with the cold storage tank outlet pump (37) and the cold storage tank outlet valve (36), the cold storage tank outlet valve (36) is connected with the heat exchange inlets of the air circulation heat end first heat exchanger (2), the air circulation heat end second heat exchanger (4), and the air circulation heat end third heat exchanger (6), the hot oil after heat exchange enters the heat storage tank (24); meanwhile, propane is stored in the cold storage circulation low-temperature tank (27) as a cold storage circulation medium, the cold storage circulation low-temperature tank (27) is connected with the cold storage circulation first control valve (28) and the cold storage circulation cold pump (44), the cold storage medium is delivered by the cold storage circulation cold pump (44) to the cold storage circulation cold end heat exchanger (7) inlet, and the cold storage circulation cold end heat exchanger (7) outlet is connected with the cold storage circulation normal-temperature tank (26). The expansion energy release unit comprises a liquid storage tank (11), a liquid storage tank outlet valve (46), a low-temperature pressurizing pump (12), a cold accumulation cycle normal-temperature end heat exchanger (13), a cold accumulation cycle low-temperature tank (27), a cold accumulation cycle normal-temperature tank (26), a cold accumulation cycle first control valve (28), a cold accumulation cycle second control valve (47), a cold accumulation cycle normal-temperature pump (45), a preheater (23), a heat storage tank (24), a cold storage tank (25), a heat storage tank outlet pump (39), a heat storage tank outlet valve (38), an air circulation cold end first heat exchanger (14), a first-stage air expander (15), an air circulation cold end second heat exchanger (16), a second-stage air expander (17), an air circulation cold end third heat exchanger (18), a light-heat first heat exchanger (19), a third-stage air expander (20), a light-heat second heat exchanger (21), and a fourth-stage air expander (22); normal-pressure liquid air is stored in the liquid storage tank (11) as an energy storage medium, the liquid storage tank (11) is connected with the liquid storage tank outlet valve (46) and the low-temperature pressurizing pump (12) at the outlet, the low-temperature pressurizing pump (12) delivers the air medium to the cold accumulation cycle normal-temperature end heat exchanger (13), the air medium is heated and then enters the preheater (23), the preheater (23) is connected with the air circulation cold end first heat exchanger (14) at the outlet, the heated air medium enters the first-stage air expander (15) to output electric energy, the first-stage air expander (15) is connected with the air circulation cold end second heat exchanger (16) at the outlet, the heated air medium enters the second-stage air expander (17), and then the air enters the air circulation cold end third heat exchanger (18) and the light-heat first heat exchanger (19) in sequence to be heated, the heated air medium enters the third-stage air expander (20), the outlet air enters the light-heat second heat exchanger (21) to be heated, the heated air medium enters the fourth-stage air expander (22), and the fourth-stage air expander (22) is connected with the preheater (23) at the outlet; meanwhile, the heat oil storing multi-stage compressed heat energy enters the heat storage tank outlet pump (39) and the heat storage tank outlet valve (38) from the heat storage tank (24), the heat oil is used as a heat supply medium and enters the heat exchange inlets of the air circulation cold end first heat exchanger (14), the air circulation cold end second heat exchanger (16), and the air circulation cold end third heat exchanger (18) in sequence, and the heat-exchanged heat oil enters the cold storage tank (25); meanwhile, the working medium propane in the cold accumulation cycle normal-temperature tank (26) enters the cold accumulation cycle second control valve (47) and the cold accumulation cycle normal-temperature pump (45), is then heated in the cold accumulation cycle normal-temperature end heat exchanger (13), and finally the low-temperature propane is stored in the cold accumulation cycle low-temperature tank (27). The photo-thermal power generation system comprises a solar heat collector (31), a hot tank (29), a cold tank (30), a 1# hot tank outlet pump (40), a 2# hot tank outlet pump (42), a 1# hot tank outlet valve (41), a 2# hot tank outlet valve (43), a photo-thermal first heat exchanger (19), a photo-thermal second heat exchanger (21) and an evaporator (34); the solar heat collector (31) converts solar energy into heat energy by collecting sunlight and transmits the heat energy to a solar heat storage medium in the hot tank (29); the hot tank (29) has two outlets: one is connected to the 1# hot tank outlet pump (40) and the 1# hot tank outlet valve (41), and the 1# hot tank outlet valve (41) is connected to the photo-thermal first heat exchanger (19) and the photo-thermal second heat exchanger (21), respectively; the solar heat storage medium is collected at the outlets of the photo-thermal first heat exchanger (19) and the photo-thermal second heat exchanger (21) and then enters the evaporator (34); the other outlet is connected to the 2# hot tank outlet pump (42) and the 2# hot tank outlet valve (43), and the solar heat storage medium directly enters the evaporator (34); the outlet of the heat exchange end of the evaporator (34) is connected to the cold tank (30). The organic Rankine cycle power generation system comprises an evaporator (34), a turbine (33), a condenser (32) and a pump (35); the heat exchange end of the evaporator (34) is connected to the outlets of the photo-thermal first heat exchanger (19) and the photo-thermal second heat exchanger (21) to heat the working medium by the solar heat storage medium; the outlet of the evaporator (34) is connected to the turbine (33); the working medium expands to do work and then enters the condenser (32); the outlet of the condenser (32) is connected to the pump (35); the working medium pressurized by the pump (35) enters the inlet of the evaporator (34).

2. The liquid air energy storage system for solar step- utilization according to claim 1, characterized in that: In the photo-thermal power generation system, the heat energy of the solar heat storage medium is utilized in stages: firstly, the solar heat storage medium collects heat in the hot tank (29); then, the solar heat storage medium enters the photo-thermal first heat exchanger (19) and the photo-thermal second heat exchanger (21) to transfer part of the heat energy to the air medium; then, the solar heat storage medium enters the evaporator (34) to exchange heat and drive the turbine (33) of the organic Rankine cycle power generation system; then, the solar heat storage medium enters the cold tank (30) to be stored; finally, the solar heat storage medium returns to the solar heat collector (31) to collect solar heat again, and the process is repeated.

3. The liquid air energy storage system for solar step- utilization according to claim 1, characterized in that: In the first stage of the expansion unit, the working medium is heated by the preheater (23) and the air cycle cold end first heat exchanger (14) and then enters the first stage air expander (15) with low power, whose operating temperature range is 370-500℃; in the second stage of the expansion unit, the working medium is heated by the air cycle cold end second heat exchanger (16) and then enters the second stage air expander (17), whose operating temperature range is 370-500℃; in the third stage of the expansion unit, the air cycle cold end third heat exchanger (18) and the photothermal first heat exchanger (19) constitute a parallel heating unit, and the working medium enters the third stage air expander (20) after being heated to a high temperature, whose operating temperature range is 450-900℃; in the fourth stage of the expansion unit, the working medium enters the photothermal second heat exchanger (21) and then enters the fourth stage air expander (22), whose operating temperature range is 450-900℃.

4. The liquid air energy storage system for solar step- utilization of claim 1, wherein: The first stage air expander (15), the second stage air expander (17), the third stage air expander (20) and the fourth stage air expander (22) are coaxially connected.

5. The liquid air energy storage system for solar step- utilization of claim 1, wherein: The liquid air energy storage subsystem is composed of at least three compressors. When the liquid air energy storage subsystem is composed of three compressors, i.e. the first stage compressor (1), the second stage compressor (3) and the third stage compressor (5), centrifugal compressors are used, and the comprehensive pressure ratio range of the inlet and outlet is 8-10; the corresponding air cycle hot end heat exchanger, i.e. the air cycle hot end first heat exchanger (2), the air cycle hot end second heat exchanger (4) and the air cycle hot end third heat exchanger (6).

6. The liquid air energy storage system for solar step- utilization of claim 1, wherein: The gas-liquid separator (10) is a vertical gravity type separator, and the separated liquid air enters the liquid storage tank (11), and the separated gaseous air enters the first stage compressor.

7. A method of operating a solar cascaded liquid air energy storage system according to any one of claims 1 to 6, characterized in that: The liquid air energy storage subsystem has two operating stages: 1) energy storage stage, the expansion energy release unit temporarily stops working, the electric energy output by the photo-thermal power generation system is mostly used as the power source of the liquefied energy storage unit, and the excess electric energy is stored in the storage tank (11) in the form of liquid air; specifically, the storage tank outlet valve (46) is closed, the low-temperature pressurizing pump (12) is stopped, the cold storage tank outlet valve (36) is opened, the cold storage tank outlet pump (37) is started, the hot storage tank outlet valve (38) is closed, the first control valve (28) of the cold storage cycle is opened, the cold storage cycle cold pump (44) is started, the second control valve (47) of the cold storage cycle is closed, and the multi-stage compressor is put into operation; the ambient air enters the multi-stage compressor after being compressed, enters the corresponding air circulation heat end heat exchanger for cooling, the high-pressure air enters the cold storage cycle cold end heat exchanger (7) of the cold storage cycle for cooling to a liquid temperature, and then enters the low-temperature turbine (8) to expand to the ambient pressure; the air is throttled by the throttle valve (9) and becomes liquid by the gas-liquid separator (10), and is finally stored in the storage tank (11); the heat exchange medium in the cold storage tank (25) is transported to the multi-stage air circulation heat end heat exchanger by the cold storage tank outlet pump (37) to cool the compressed high-temperature air, and then the heat exchange medium enters the hot storage tank (24) for storage; the low-temperature propane in the cold storage cycle low-temperature tank (27) is transported to the cold storage cycle cold end heat exchanger (7) by the cold storage cycle cold pump (44), cools the air medium, and then enters the cold storage cycle normal-temperature tank (26) for storage; 2) energy release stage, the liquefied energy storage unit temporarily stops working, and the liquid air is expanded to output electric energy after being pressurized and heated; specifically, the liquid storage tank outlet valve (46) is opened, the low-temperature pressurizing pump (12) is started, the cold storage circulation first control valve (28) is closed, the cold storage circulation second control valve (47) is opened, the cold storage circulation normal-temperature pump (45) is operated, the cold storage tank outlet valve (36) is closed, the heat storage tank outlet valve (38) is opened, the heat storage tank outlet pump (39) is operated, the first-stage air expander (15), the second-stage air expander (17), the third-stage air expander (20) and the fourth-stage air expander (22) are put into operation; the liquid air is transported into the cold storage circulation normal-temperature end heat exchanger (13) of the cold storage circulation by the low-temperature pressurizing pump (12), and the cold energy is stored to the cold storage circulation, and then the air working medium is preheated by the preheater (23) and the air circulation cold end first heat exchanger (14) and the air circulation cold end second heat exchanger (16), and then enters the first-stage air expander (15) to be expanded for the first time, generates electric energy and outputs the electric energy to the outside, is heated by the air circulation cold end third heat exchanger (18) and the light-heat system supplied light-heat first heat exchanger (19) after being heated by the air circulation cold end second heat exchanger (16), guarantees a higher working medium temperature, enters the third-stage air expander (20) to be expanded for the third time, is heated by the light-heat second heat exchanger (21) alone, and then enters the fourth-stage air expander (22) to be expanded for the fourth time, and the outlet air enters the preheater (23) to preheat the air as the working medium; the propane in the cold storage circulation normal-temperature tank (26) is transported to the cold storage circulation normal-temperature end heat exchanger (13) by the cold storage circulation normal-temperature pump (45), and the cold energy of the propane carrying the liquid air after heat exchange is stored in the cold storage circulation low-temperature tank (27); the hot oil in the heat storage tank (24) is transported to the air circulation cold end first heat exchanger (14), the air circulation cold end second heat exchanger (16) and the air circulation cold end third heat exchanger (18) by the heat storage tank outlet pump (39) respectively, and the hot oil heats the air medium and is then stored in the cold storage tank (25); The light-heat power generation sub-system and the organic Rankine cycle power generation sub-system have two operation stages: 1) energy storage stage, the solar heat collector (31) generates high-temperature heat energy by collecting solar radiation, heats the solar energy heat storage medium in the heat tank (29), the solar energy heat storage medium directly supplies the organic Rankine cycle power generation sub-system to generate power, and most of the output electric energy is used as the power source of the liquefied energy storage unit, and the liquefied air is stored; specifically, the 2# heat tank outlet valve (43) is opened, the 1# heat tank outlet valve (41) is closed, the 2# heat tank outlet pump (42) is operated, and the steam turbine (33) is put into operation; the solar energy heat storage medium in the heat tank (29) is transported to the condenser (32) of the organic Rankine cycle power generation sub-system by the 2# heat tank outlet pump (42), the solar energy heat storage medium heats the organic Rankine cycle working medium, the organic Rankine cycle working medium is expanded by the steam turbine (33) to generate power, most of the output electric energy supplies the multi-stage compressor, the liquefied air is stored, and a small part of the electric energy supplies the user; 2) energy release stage, the solar heat storage medium first releases heat to the air medium in the expansion energy release unit of the liquid air energy storage subsystem, and then the organic Rankine cycle power generation subsystem is powered to generate electricity; specifically, the 1# hot tank outlet valve (41) is opened, the 2# hot tank outlet valve (43) is closed, the 1# hot tank outlet pump (40) is operated, the light-heat first heat exchanger (19) and the light-heat second heat exchanger (21) are put into operation, and the steam turbine (33) is put into operation; the solar heat storage medium in the hot tank (29) is transported to the light-heat first heat exchanger (19) and the light-heat second heat exchanger (21) by the 1# hot tank outlet pump (40), the solar heat storage medium heats the air medium, and then enters the condenser (32) of the organic Rankine cycle power generation subsystem to exchange heat, and finally enters the cold tank (30).

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