A liquid air energy storage system based on an alternately operated low-temperature storage and replacement cold integrated device
By introducing alternating cryogenic storage and heat exchange integrated devices into the liquid air energy storage system, series and parallel control of the cold storage packed bed is achieved, solving the problems of large equipment footprint and low utilization rate, and improving system efficiency and safety.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- SHIJIAZHUANG TIEDAO UNIV
- Filing Date
- 2025-05-21
- Publication Date
- 2026-05-29
AI Technical Summary
In existing liquid air energy storage technologies, the cold storage unit, main heat exchanger, and evaporator operate independently, resulting in numerous equipment components, a large footprint, low utilization rate, and unbalanced thermal stress, which increases investment costs and irreversible losses.
The low-temperature storage and heat exchange integrated device adopts alternating operation. It integrates the functions of cold storage and liquefaction heat exchanger by controlling the alternating operation of the cold storage packed bed through series and parallel connection, replacing the traditional liquefaction heat exchanger and evaporator.
It reduces heat exchange losses, improves the overall efficiency and equipment utilization of liquid air energy storage systems, reduces operating costs, and enhances the flexibility and safety of the system.
Smart Images
Figure CN224305529U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of liquid air energy storage technology, and in particular to a liquid air energy storage system based on an alternating operation cryogenic storage and cooling integrated device. Background Technology
[0002] Liquid air energy storage technology compresses and cools air to a liquid state (-196°C) and stores it in cryogenic tanks. When needed, it generates electricity by heating, vaporizing, and expanding to drive a generator. It combines physical energy storage and heat recovery technologies, making it suitable for large-scale, long-term energy storage. Energy can be stored for days to weeks, compensating for the intermittency of wind and solar power. Compared to traditional energy storage methods, liquid air energy storage uses air as the storage medium, is non-toxic and pollution-free, and poses no risk of combustion or explosion, making it safer and more reliable than lithium batteries. It is not dependent on terrain conditions (unlike pumped-storage which requires reservoirs), allowing for flexible deployment anywhere. It has high energy density and can also be integrated with other industrial processes (such as waste heat recovery) to improve energy efficiency.
[0003] Current liquid air energy storage technologies, such as the patent "A Liquid Air Energy Storage System" (202420777420.X), are typically based on traditional liquid air energy storage designs, mainly including air compression units, air purification units, air liquefaction and storage units, air expansion power generation units, cold storage units, and heat storage units. Their cold storage units, main heat exchangers, and evaporators operate independently, transferring heat to liquefy and vaporize the air. This results in a large number of components in the liquid air energy storage equipment, a large footprint, and increased investment costs. Furthermore, in conventional liquid air energy storage, most of the equipment related to the discharge process is unused, and conversely, most of the equipment related to the energy storage process is unused during discharge, leading to low utilization rates of equipment components throughout the entire process and thermal stress imbalances caused by heat transfer. Therefore, optimizing the liquid air energy storage system, comprehensively integrating and optimizing equipment while ensuring performance, reducing irreversible losses during heat transfer, rationally utilizing heat and cold, and reducing equipment investment are crucial for improving the performance of liquid air energy storage systems. Utility Model Content
[0004] The purpose of this invention is to address the shortcomings of existing technologies by proposing a liquid air energy storage system based on an alternating operation low-temperature storage and heat exchange integrated device. This system realizes an alternating operation low-temperature storage and heat exchange method in a liquid air energy storage unit, enabling the cold storage filling bed to simultaneously function as a cold storage, liquefaction heat exchanger, and evaporator. Furthermore, the low-temperature storage and heat exchange integrated device also has the function of alternating operation controlled by series and parallel connections.
[0005] To achieve the above objectives, the present invention adopts the following technical solution:
[0006] A liquid air energy storage system based on an alternating cryogenic storage and heat exchange integrated device includes an air compression subsystem, a cryogenic storage and heat exchange integrated device, a cryogenic throttling valve, a cryogenic storage tank, a liquid air pump, a thermal storage subsystem, and an air expansion subsystem.
[0007] The air compression subsystem is connected to the cryogenic storage and heat exchange integrated device and the heat storage subsystem respectively; the cryogenic storage and heat exchange integrated device is connected to the cryogenic storage tank, the liquid air pump and the air expansion subsystem, and the air expansion subsystem is connected to the heat storage subsystem.
[0008] Preferably, the air compression subsystem includes a first compressor, a first cooler, a second compressor, a second cooler, an air purification module, a three-way valve, a third compressor, a third cooler, a fourth compressor, and a fourth cooler;
[0009] The input end of the first compressor is used to input ambient air, the output end of the first compressor is connected to the air input end of the first cooler, and the air output end of the first cooler is connected to the air input end of the second compressor; the input end of the second compressor is used to input the air compressed and cooled by the first compressor and the first cooler, the output end of the second compressor is connected to the air input end of the second cooler, and the air output end of the second cooler is connected to the air input end of the third compressor in sequence through an air purification module and a three-way valve;
[0010] The input end of the third compressor is used to input air for further cooling and pressurization. The output end of the third compressor is connected to the air input end of the third cooler. The air output end of the third cooler is connected to the air input end of the fourth compressor. The input end of the fourth compressor is used to input air for final cooling and pressurization. The output end of the fourth compressor is connected to the air input end of the fourth cooler. The air output end of the fourth cooler is connected to the low-temperature storage and heat exchange integrated device.
[0011] The air compression subsystem is used to compress, cool, and purify air in the environment. After processing, it obtains high-pressure, room-temperature gaseous air, which is ready to be transferred to the cryogenic storage and heat exchange integrated device for further processing.
[0012] Preferably, the air expansion subsystem includes a first heater, a first expander, a second heater, a second expander, a third heater, a third expander, a fourth heater, and a fourth expander;
[0013] The air output terminal of the first heater is connected to the input terminal of the first expander, and the air output terminal of the first expander is connected to the air input terminal of the second heater; the air output terminal of the second heater is connected to the input terminal of the second expander, and the air output terminal of the second expander is connected to the air input terminal of the third heater; the air output terminal of the third heater is connected to the input terminal of the third expander, and the air output terminal of the third expander is connected to the air input terminal of the fourth heater; the air output terminal of the fourth heater is connected to the input terminal of the fourth expander, and the exhaust gas from the fourth expander is discharged into the environment.
[0014] The air expansion subsystem is used to further heat and expand the high-pressure gaseous air from the cryogenic storage and heat exchange integrated device. The expanded air expander does work to drive the generator to generate electricity. Finally, the last stage expander discharges air at ambient pressure, completing the power generation process.
[0015] Preferably, the thermal storage subsystem includes a normal temperature water tank, a hot water tank, a first water supply pump, a second water supply pump, and a radiator;
[0016] The output end of the ambient temperature water tank is connected to the water input ends of the first cooler, the second cooler, the third cooler, and the fourth cooler respectively via the first water supply pump. The water output ends of the first cooler, the second cooler, the third cooler, and the fourth cooler are all connected to the input end of the hot water tank.
[0017] The output end of the hot water tank is connected to the water input ends of the first heater, the second heater, the third heater, and the fourth heater respectively via a second water supply pump. The water output ends of the first heater, the second heater, the third heater, and the fourth heater are connected to the input end of the room temperature water tank via radiators.
[0018] The thermal storage subsystem uses a first and a second water supply pump to drive water circulation. When the cold water in the ambient temperature tank flows through the heat exchanger of the air compression subsystem, it carries away the heat generated during air compression and stores it in the hot water tank. This heat is then used to heat the air used for expansion and power generation through the first, second, third, and fourth heaters, enabling it to produce more electricity. Simultaneously, when the hot water in the hot water tank flows through the first, second, third, and fourth heaters of the air expansion subsystem, it carries away the cold energy generated during air expansion and stores it in the ambient temperature tank. This cold energy is then utilized in the air compression process through the first, second, third, and fourth coolers, improving the system's liquefaction rate and overall efficiency.
[0019] Preferably, the cryogenic storage and heat exchange integrated device includes a first reversing three-way control valve, a second reversing three-way control valve, a third reversing three-way control valve, a fourth reversing three-way control valve, a fifth reversing three-way control valve, a first cold storage filling bed, a second cold storage filling bed, a third cold storage filling bed, a fourth cold storage filling bed, a first switching valve, a second switching valve, a third switching valve, a sixth reversing three-way control valve, a seventh reversing three-way control valve, an eighth reversing three-way control valve, a ninth reversing three-way control valve, and a tenth reversing three-way control valve;
[0020] Energy storage mode 1: The air output end of the fourth cooler is split into two streams after passing through the first reversing three-way control valve. Each stream is connected to the upper input end of the first and second cold storage filling beds through the second and third reversing three-way control valves, respectively. The lower output ends of the first and second cold storage filling beds are merged into one stream through the sixth and seventh reversing three-way control valves, respectively, and then connected to the input end of the cryogenic storage tank through the tenth reversing three-way control valve and the cryogenic throttling valve.
[0021] The output end of the cryogenic storage tank is connected to the lower input end of the third and fourth cold storage filling beds through the eighth and ninth reversing three-way control valves, respectively. The upper output ends of the third and fourth cold storage filling beds are connected to the air input end of the third compressor through the fourth and fifth reversing three-way control valves, respectively.
[0022] Energy storage mode two: The air output end of the fourth cooler is split into two streams after passing through the first reversing three-way control valve. Each stream is connected to the upper input end of the third and fourth cold storage filling beds through the fourth and fifth reversing three-way control valves, respectively. The lower output ends of the third and fourth cold storage filling beds are merged into one stream through the eighth and ninth reversing three-way control valves, and then connected to the input end of the cryogenic storage tank through the tenth reversing three-way control valve and the cryogenic throttling valve.
[0023] The output end of the cryogenic storage tank is connected to the lower input end of the first and second cold storage filling beds through the sixth and seventh reversing three-way control valves, respectively; the upper output ends of the first and second cold storage filling beds are connected to the air input end of the third compressor through the second and third reversing three-way control valves, respectively.
[0024] Discharge mode: The output end of the cryogenic storage tank is connected to the lower input end of the fourth cold storage bed in sequence through a liquid air pump, a tenth reversing three-way control valve, and a ninth reversing three-way control valve. The upper output end of the fourth cold storage bed is connected to the lower input end of the third cold storage bed through a third switching valve. The upper output end of the third cold storage bed is connected to the lower input end of the second cold storage bed through a second switching valve. The upper output end of the second cold storage bed is connected to the lower input end of the first cold storage bed through a first switching valve. The upper output end of the first cold storage bed is connected to the first heater in sequence through a second reversing three-way control valve and a first reversing three-way control valve.
[0025] The integrated cryogenic storage and heat exchange device creates different circuits between the cryogenic storage and heat exchange beds by controlling a three-way control valve and a switching valve.
[0026] By adopting the above technical solution, the system consists of six conventional subsystems and one new integrated unit: an air compression subsystem, a cryogenic storage and heat exchange integrated unit, a cryogenic throttling valve, a cryogenic storage tank, a liquid air pump, a heat storage subsystem, and an air expansion subsystem. During energy storage, air is compressed, purified, and cooled before being transferred to the cryogenic storage and heat exchange integrated unit. Inside its cold storage bed, the air absorbs cold energy and liquefies. It is then further depressurized and cooled by the cryogenic throttling valve before entering the cryogenic storage tank. During discharge, air is drawn from the cryogenic storage tank by the liquid air pump and enters the cryogenic storage and heat exchange integrated unit to release cold energy and become gaseous air. At this point, the cryogenic storage and heat exchange integrated unit acts as an evaporator. Subsequently, the gaseous air is heated and expanded to generate electricity. Based on traditional liquid air energy storage units, it uses a three-way control valve and a switching valve to create different loops between the cold storage beds, enabling the four cold storage beds to operate alternately in series and parallel. This gives it the ability to convert between different functions, replacing the functions of the liquefaction heat exchanger and evaporator. Not only does it reduce heat exchange losses, but the cold storage packed bed in series also improves the evaporation efficiency of liquid air, thereby increasing the overall efficiency of the system.
[0027] Compared with the prior art, the present invention has the following beneficial effects:
[0028] 1. This utility model uses multiple arrays of cold storage filling beds and combines them in an alternating manner through a certain control method to conduct direct contact heat exchange with the mainstream air, eliminating the liquefaction heat exchanger and evaporator parts of traditional liquid air energy storage units, making the overall system simpler and reducing maintenance and operation costs.
[0029] 2. Compared with traditional liquid air energy storage units, this utility model uses liquefaction heat exchangers and evaporators to exchange heat with the mainstream air in the secondary and tertiary stages. It directly stores the heat and cold of the mainstream air through four cold storage packed beds connected in series, which can gradually vaporize the mainstream air, increase the depth of evaporation or liquefaction, reduce the energy loss of heat storage and exchange, and thus increase the overall efficiency of the system.
[0030] 3. This utility model adopts a series-parallel connection of cold storage filling beds to form a cold storage filling bed group with different functions and an operation mode for the energy storage process. As the mode 1 and mode 2 are switched, the function of the cold storage filling bed group is also changed accordingly. This measure makes full use of the cold energy of the unliquefied air from the low temperature tank, thereby improving the air liquefaction rate. Attached Figure Description
[0031] Figure 1 This is a schematic diagram of the overall structure of this utility model;
[0032] Figure 2 This is a schematic diagram of the energy storage process of this utility model;
[0033] Figure 3 This is a schematic diagram of the discharge process of this utility model.
[0034] In the diagram: 100 Air compression subsystem, 101 First compressor, 102 First cooler, 103 Second compressor, 104 Second cooler, 105 Air purification module, 106 Three-way valve, 107 Third compressor, 108 Third cooler, 109 Fourth compressor, 110 Fourth cooler, 200 Low-temperature storage and heat exchange integrated device, 201 First reversing three-way control valve, 202 Second reversing three-way control valve, 203 Third reversing three-way control valve, 204 Fourth reversing three-way control valve, 205 Fifth reversing three-way control valve, 206 First cold storage bed, 207 Second cold storage bed, 208 Third cold storage bed, 209 Fourth cold storage bed, 210 First switching valve, 21 1 Second switching valve, 212 Third switching valve, 213 Sixth reversing three-way control valve, 214 Seventh reversing three-way control valve, 215 Eighth reversing three-way control valve, 216 Ninth reversing three-way control valve, 217 Tenth reversing three-way control valve, 300 Cryogenic throttle valve, 400 Cryogenic storage tank, 500 Liquid air pump, 600 Thermal storage subsystem, 601 Normal temperature water tank, 602 Hot water tank, 603 First water supply pump, 604 Second water supply pump, 605 Radiator, 700 Air expansion subsystem, 701 First heater, 702 First expander, 703 Second heater, 704 Second expander, 705 Third heater, 706 Third expander, 707 Fourth heater, 708 Fourth expander. Detailed Implementation
[0035] The technical solutions in the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings, so that those skilled in the art can better understand the advantages and features of this utility model, thereby making a clearer definition of the protection scope of this utility model. The embodiments described in this utility model are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.
[0036] Reference Figure 1 A liquid air energy storage system based on an alternating cryogenic storage and heat exchange integrated device includes an air compression subsystem 100, a cryogenic storage and heat exchange integrated device 200, a cryogenic throttling valve 300, a cryogenic storage tank 400, a liquid air pump 500, a thermal storage subsystem 600, and an air expansion subsystem 700.
[0037] The air compression subsystem 100 is connected to the cryogenic storage and heat exchange integrated device 200 and the heat storage subsystem 600 respectively; the cryogenic storage and heat exchange integrated device 200 is connected to the cryogenic storage tank 400, the liquid air pump 500 and the air expansion subsystem 700, and the air expansion subsystem 700 is connected to the heat storage subsystem 600.
[0038] Specifically, the air compression subsystem 100 includes a first compressor 101, a first cooler 102, a second compressor 103, a second cooler 104, an air purification module 105, a three-way valve 106, a third compressor 107, a third cooler 108, a fourth compressor 109, and a fourth cooler 110.
[0039] The input terminal of the first compressor 101 is used to input ambient air, the output terminal of the first compressor 101 is connected to the air input terminal of the first cooler 102, and the air output terminal of the first cooler 102 is connected to the air input terminal of the second compressor 103; the input terminal of the second compressor 103 is used to input the air compressed and cooled by the first compressor 101 and the first cooler 102, the output terminal of the second compressor 103 is connected to the air input terminal of the second cooler 104, and the air output terminal of the second cooler 104 is connected to the air input terminal of the third compressor 107 in sequence through the air purification module 105 and the three-way valve 106;
[0040] The input end of the third compressor 107 is used to input air for further cooling and pressurization. The output end of the third compressor 107 is connected to the air input end of the third cooler 108. The air output end of the third cooler 108 is connected to the air input end of the fourth compressor 109. The input end of the fourth compressor 109 is used to input air for final cooling and pressurization. The output end of the fourth compressor 109 is connected to the air input end of the fourth cooler 110. The air output end of the fourth cooler 110 is connected to the low-temperature storage and heat exchange integrated device 200.
[0041] The air compression subsystem 100 is used to compress, cool and purify air in the environment, and obtain high-pressure, room-temperature gaseous air after processing, which is ready to be passed to the low-temperature storage and heat exchange integrated device 200 for further processing.
[0042] Specifically, the air expansion subsystem 700 includes a first heater 701, a first expander 702, a second heater 703, a second expander 704, a third heater 705, a third expander 706, a fourth heater 707, and a fourth expander 708;
[0043] The air output terminal of the first heater 701 is connected to the input terminal of the first expander 702, and the output terminal of the first expander 702 is connected to the air input terminal of the second heater 703; the air output terminal of the second heater 703 is connected to the input terminal of the second expander 704, and the output terminal of the second expander 704 is connected to the air input terminal of the third heater 705; the air output terminal of the third heater 705 is connected to the input terminal of the third expander 706, and the output terminal of the third expander 706 is connected to the air input terminal of the fourth heater 707; the air output terminal of the fourth heater 707 is connected to the input terminal of the fourth expander 708, and the output terminal of the fourth expander 708 discharges the exhaust gas into the environment.
[0044] The air expansion subsystem 700 is used to further heat and expand the high-pressure gaseous air from the cryogenic storage and heat exchange integrated device 200. The expanded air expander does work to drive the generator to generate electricity. Finally, the last stage expander discharges air at ambient pressure, completing the power generation process.
[0045] Specifically, the thermal storage subsystem 600 includes a normal temperature water tank 601, a hot water tank 602, a first water supply pump 603, a second water supply pump 604, and a radiator 605;
[0046] The output end of the ambient temperature water tank 601 is connected to the water input ends of the first cooler 102, the second cooler 104, the third cooler 108, and the fourth cooler 110 respectively via the first water supply pump 603. The water output ends of the first cooler 102, the second cooler 104, the third cooler 108, and the fourth cooler 110 are all connected to the input end of the hot water tank 602.
[0047] The output end of the hot water tank 602 is connected to the water input ends of the first heater 701, the second heater 703, the third heater 705, and the fourth heater 707 respectively through the second water supply pump 604. The water output ends of the first heater 701, the second heater 703, the third heater 705, and the fourth heater 707 are connected to the input end of the room temperature water tank 601 through the radiator 605.
[0048] The thermal storage subsystem 600 uses a first water supply pump 603 and a second water supply pump 604 to drive water circulation. When the cold water in the ambient temperature water tank 601 flows through the heat exchanger of the air compression subsystem 100, it carries away the heat generated during air compression and stores it in the hot water tank 602. Subsequently, the heat is used to provide heat to the air used for expansion and power generation through the first heater 701, the second heater 703, the third heater 705, and the fourth heater 707, enabling it to generate more electricity. At the same time, when the hot water in the hot water tank 602 flows through the first heater 701, the second heater 703, the third heater 705, and the fourth heater 707 of the air expansion subsystem 700, it carries away the cold energy generated during air expansion and stores it in the ambient temperature water tank 601. This cold energy is then used in the air compression process through the first cooler 102, the second cooler 104, the third cooler 108, and the fourth cooler 110, improving the system's liquefaction rate and overall efficiency.
[0049] Specifically, the cryogenic storage and heat exchange integrated device 200 includes a first reversing three-way control valve 201, a second reversing three-way control valve 202, a third reversing three-way control valve 203, a fourth reversing three-way control valve 204, a fifth reversing three-way control valve 205, a first cold storage filling bed 206, a second cold storage filling bed 207, a third cold storage filling bed 208, a fourth cold storage filling bed 209, a first switching valve 210, a second switching valve 211, a third switching valve 212, a sixth reversing three-way control valve 213, a seventh reversing three-way control valve 214, an eighth reversing three-way control valve 215, a ninth reversing three-way control valve 216, and a tenth reversing three-way control valve 217.
[0050] Energy storage mode 1: The air output end of the fourth cooler 110 is divided into two streams after passing through the first reversing three-way control valve 201. Each stream is connected to the upper input end of the first cold storage bed 206 and the second cold storage bed 207 through the second reversing three-way control valve 202 and the third reversing three-way control valve 203, respectively. The lower output ends of the first cold storage bed 206 and the second cold storage bed 207 are merged into one stream through the sixth reversing three-way control valve 213 and the seventh reversing three-way control valve 214, respectively. Then, the stream is connected to the input end of the low-temperature storage tank 400 through the tenth reversing three-way control valve 217 and the low-temperature throttle valve 300.
[0051] The output end of the cryogenic storage tank 400 is connected to the lower input end of the third cold storage bed 208 and the fourth cold storage bed 209 through the eighth reversing three-way control valve 215 and the ninth reversing three-way control valve 216, respectively. The upper output ends of the third cold storage bed 208 and the fourth cold storage bed 209 are connected to the air input end of the third compressor 107 through the fourth reversing three-way control valve 204 and the fifth reversing three-way control valve 205, respectively.
[0052] Energy storage mode two: The air output end of the fourth cooler 110 is divided into two streams after passing through the first reversing three-way control valve 201. Each stream is connected to the upper input end of the third cold storage bed 208 and the fourth cold storage bed 209 through the fourth reversing three-way control valve 204 and the fifth reversing three-way control valve 205, respectively. The lower output ends of the third cold storage bed 208 and the fourth cold storage bed 209 are merged into one stream through the eighth reversing three-way control valve 215 and the ninth reversing three-way control valve 216, and then connected to the input end of the low temperature storage tank 400 through the tenth reversing three-way control valve 217 and the low temperature throttle valve 300.
[0053] The output end of the cryogenic storage tank 400 is connected to the lower input end of the first cold storage bed 206 and the second cold storage bed 207 through the sixth reversing three-way control valve 213 and the seventh reversing three-way control valve 214, respectively; the upper output end of the first cold storage bed 206 and the second cold storage bed 207 are connected to the air input end of the third compressor 107 through the second reversing three-way control valve 202 and the third reversing three-way control valve 203, respectively.
[0054] Discharge mode: The output terminal of the cryogenic storage tank 400 is connected to the lower input terminal of the fourth cold storage bed 209 in sequence through the liquid air pump 500, the tenth reversing three-way control valve 217, and the ninth reversing three-way control valve 216. The upper output terminal of the fourth cold storage bed 209 is connected to the lower input terminal of the third cold storage bed 208 in sequence through the third switching valve 212. The upper output terminal of the third cold storage bed 208 is connected to the lower input terminal of the second cold storage bed 207 in sequence through the second switching valve 211. The upper output terminal of the second cold storage bed 207 is connected to the lower input terminal of the first cold storage bed 206 in sequence through the first switching valve 210. The upper output terminal of the first cold storage bed 206 is connected to the first heater 701 in sequence through the second reversing three-way control valve 202 and the first reversing three-way control valve 201.
[0055] The integrated cryogenic storage and heat exchange device 200 creates different circuits between the cryogenic storage and heat exchange beds by controlling a three-way control valve and a switching valve.
[0056] The implementation method of the cryogenic storage and heat exchange integrated device 200 includes the following steps:
[0057] During energy storage, the first switching valve 210, the second switching valve 211, and the third switching valve 212 remain closed. The reversing of the three-way control valve can be determined according to... Figure 2 As shown, the integrated low-temperature storage and heat exchange unit can simultaneously operate two cold storage modes alternately, and the four cold storage packed beds can be connected in parallel in pairs, alternating between different cold storage operation modes to achieve different functions, such as... Figure 2 As shown.
[0058] Energy storage process, cold storage operation mode 1: Initially, the first cold storage bed 206 and the second cold storage bed 207 contain a large amount of cold energy, while the third cold storage bed 208 and the fourth cold storage bed 209 also contain a small amount of cold energy. After energy storage begins, the ambient temperature and high pressure gaseous air is split into two streams after passing through the first reversing three-way control valve 201. These streams then pass through the second reversing three-way control valve 202 and the third reversing three-way control valve 203, respectively, and enter the first cold storage bed 206 and the second cold storage bed 207. At this time, the two cold storage beds are essentially operating in parallel. The ambient temperature and high pressure gaseous air absorbs a large amount of cold energy inside and liquefies. It then exits from the cold storage bed, passes through the sixth reversing three-way control valve 213 and the seventh reversing three-way control valve 214, and finally merges into one stream after passing through the tenth reversing three-way control valve 217. The liquid air then expands and cools further through the cryogenic throttling valve 300. During this expansion, a small amount of gaseous air is released from the liquid air. This stream of low-temperature, high-pressure air containing both gas and liquid phases finally enters the cryogenic storage tank 400. To fully utilize the cooling capacity of the gaseous air and ensure that the air storage tank 400 is entirely filled with liquid air, the low-temperature, high-pressure gaseous air discharged from the air storage tank 400 is split into two streams. These streams then pass through the eighth reversing three-way control valve 215 and the ninth reversing three-way control valve 216, respectively, and enter the third and fourth cold storage packed beds 208 and 209. After releasing some cooling capacity within these gaseous air streams, they then pass through the fourth and fifth reversing three-way control valves 204 and 205, respectively, and converge into a single stream. This stream is then transported to the three-way valve 106 and enters the air compression subsystem to provide cooling capacity to offset the heat of compression. After the third and fourth cold storage beds 208 and 209 have stored the maximum amount of gaseous air from the air storage tank 400, the energy storage process in cold storage mode 1 ends. At the same time, a small amount of cold energy will remain in the first and second cold storage beds 206 and 207.
[0059] Energy storage process, cold storage operation mode 2: Immediately after the end of mode 1, energy storage continues. At room temperature and high pressure, the gaseous air is split into two streams after passing through the first reversing three-way control valve 201. These streams then pass through the fourth and fifth reversing three-way control valves 204 and 205 respectively, entering the third and fourth cold storage packed beds 208 and 209, respectively. At this point, these two cold storage packed beds are essentially operating in parallel. The at room temperature and high pressure gaseous air absorbs a large amount of cold energy and liquefies inside, then exits from the cold storage packed beds. It passes through the eighth and ninth reversing three-way control valves 215 and 216 respectively, and finally merges into one stream after passing through the tenth reversing three-way control valve 217. The liquid air then further expands and cools down through the cryogenic throttling valve 300. During this expansion, a small amount of gaseous air is released from the liquid air. This stream of low-temperature, high-pressure air containing both gas and liquid phases finally enters the cryogenic storage tank 400. To fully utilize the cooling capacity of the gaseous air and ensure that the air storage tank 400 contains only liquid air, the low-temperature, high-pressure gaseous air discharged from the air storage tank 400 is split into two streams. These streams then pass through the sixth and seventh reversing three-way control valves 213 and 214, respectively, and enter the first cold storage bed 206 and the second cold storage bed 207. After releasing some cooling capacity within these streams, the gaseous air then passes through the second and third reversing three-way control valves 202 and 205, converging into a single stream which is then transported to the three-way valve 106 and enters the air compression subsystem to provide cooling capacity to offset the heat of compression. After the first and second cold storage beds 206 and 207 have stored all the cooling capacity of the gaseous air from the air storage tank 400 and reached their maximum value, the energy storage process in cold storage mode 2 ends. Meanwhile, a small amount of cooling capacity remains in the third and fourth cold storage beds 208 and 209.
[0060] During the discharge process, the first switching valve 210, the second switching valve 211, and the third switching valve 212 remain open, while the second reversing three-way control valve 202, the third reversing three-way control valve 203, the fourth reversing three-way control valve 204, the fifth reversing three-way control valve 205, the sixth reversing three-way control valve 213, the seventh reversing three-way control valve 214, and the eighth reversing three-way control valve 215 are all closed. The tenth reversing three-way control valve 217 and the first reversing three-way control valve 201 can be adjusted according to... Figure 3 As shown. This allows four cold storage packed beds connected in series to act as evaporators during the discharge process. The purpose is to utilize the series-connected cold storage packed beds to fully exchange heat with the low-temperature liquid air pumped from the air storage tank 400, thereby improving the evaporation and vaporization effect. Figure 3 As shown.
[0061] Discharge Process: Low-temperature, high-pressure liquid air is pumped from air storage tank 400 by liquid-air pump 500, passing through tenth reversing three-way control valve 217 and ninth reversing three-way control valve 216 into four series-connected cold storage packed beds. First, it enters the fourth cold storage packed bed 209, where it releases its cooling capacity to the packed bed, and a portion evaporates. Next, it passes through third switching valve 212 into the third cold storage packed bed 208, where it releases its cooling capacity to the packed bed, and another portion evaporates. Then, it passes through second switching valve 211 into the second cold storage packed bed 207, where it releases its cooling capacity to the packed bed, and another portion evaporates. Finally, it passes through first switching valve 210 into the first cold storage packed bed 206, where it releases its cooling capacity to the packed bed; this completes the evaporation of all the liquid air. Subsequently, this gaseous air flows through second reversing three-way control valve 202 and first reversing three-way control valve 201 into the air expansion subsystem for power generation.
[0062] The operation process and control method of the overall energy storage and discharge of this utility model are described below:
[0063] The overall energy storage process of the system is the liquefaction process of pressurized and cooled gaseous air. Specifically, the air is pressurized through an air compression subsystem, cooled by a cryogenic storage and heat exchange integrated device, and then stored in the air storage tank 400 after liquefaction.
[0064] The overall discharge process of the system is the vaporization process of liquid air absorbing heat and expanding. Specifically, air is pumped out from the air storage tank 400, evaporates and vaporizes in the cold storage packed bed, and then expands through the air expansion subsystem to generate electricity.
[0065] The control method focuses on the state of the four cold storage and heat exchange beds in the cryogenic storage and heat exchange integrated device, and changes the charging and discharging mode according to their different states.
[0066] In the energy storage process, the cold storage operation mode 1 should be switched to the energy storage process, and the switch should be made when the third and fourth cold storage beds 208 and 209 are completely filled with cold energy. This should continue until the cold energy in the first and second cold storage beds 206 and 207 is completely used up. This is to prevent a sharp drop in the air liquefaction rate and a decrease in the overall system efficiency.
[0067] Similarly, in the energy storage process cold storage operation mode 2, the switch to energy storage process cold storage operation mode 2 should be initiated when the first cold storage bed 206 and the second cold storage bed 207 are completely filled with cold energy, and should continue until the cold energy in the third cold storage bed 208 and the fourth cold storage bed 209 is completely used up. This is to prevent a sharp drop in the air liquefaction rate and a decrease in the overall system efficiency.
[0068] During the discharge process, liquid air from the air storage tank 400 enters the four series-connected cold storage beds and gradually evaporates and vaporizes into gaseous air. The discharge process should end when the four cold storage beds are completely filled with cooling capacity; otherwise, the liquid air will not be able to absorb heat and vaporize in the cold storage beds, leading to a sharp drop in power generation efficiency.
[0069] In summary, this invention realizes a low-temperature energy storage and exchange method with alternating operation in a liquid air energy storage unit, enabling the cold storage bed to simultaneously function as both a cold storage unit and an evaporator. Furthermore, the cold storage bed also possesses the capability to control alternating operation through series and parallel connections. Compared to traditional liquid air energy storage units, this invention offers advantages such as reduced footprint and increased efficiency, making it a highly efficient energy storage method.
[0070] The descriptions and practices disclosed in this utility model are readily conceived and understood by those skilled in the art, and various improvements and modifications can be made without departing from the principles of this utility model. Therefore, modifications or improvements made without deviating from the spirit of this utility model should also be considered within the scope of protection of this utility model.
Claims
1. A liquid air energy storage system based on an alternating operation cryogenic storage and heat exchange integrated device, characterized in that, It includes an air compression subsystem (100), a cryogenic storage and heat exchange integrated unit (200), a cryogenic throttling valve (300), a cryogenic storage tank (400), a liquid air pump (500), a thermal storage subsystem (600), and an air expansion subsystem (700): The air compression subsystem (100) is connected to the cryogenic storage and heat exchange integrated device (200) and the heat storage subsystem (600) respectively; the cryogenic storage and heat exchange integrated device (200) is connected to the cryogenic storage tank (400), the liquid air pump (500) and the air expansion subsystem (700), and the air expansion subsystem (700) is connected to the heat storage subsystem (600).
2. The liquid air energy storage system based on an alternating operation cryogenic storage and heat exchange integrated device according to claim 1, characterized in that, The air compression subsystem (100) includes a first compressor (101), a first cooler (102), a second compressor (103), a second cooler (104), an air purification module (105), a three-way valve (106), a third compressor (107), a third cooler (108), a fourth compressor (109), and a fourth cooler (110). The input end of the first compressor (101) is used to input ambient air, the output end of the first compressor (101) is connected to the air input end of the first cooler (102), and the air output end of the first cooler (102) is connected to the air input end of the second compressor (103); the input end of the second compressor (103) is used to input the air compressed and cooled by the first compressor (101) and the first cooler (102), the output end of the second compressor (103) is connected to the air input end of the second cooler (104), and the air output end of the second cooler (104) is connected to the air input end of the third compressor (107) in sequence through the air purification module (105) and the three-way valve (106); The input end of the third compressor (107) is used to input air for further cooling and pressurization. The output end of the third compressor (107) is connected to the air input end of the third cooler (108). The air output end of the third cooler (108) is connected to the air input end of the fourth compressor (109). The input end of the fourth compressor (109) is used to input air for final cooling and pressurization. The output end of the fourth compressor (109) is connected to the air input end of the fourth cooler (110). The air output end of the fourth cooler (110) is connected to the low-temperature storage and heat exchange integrated device (200). The air compression subsystem (100) is used to compress, cool and purify the air in the environment. After processing, it obtains high-pressure, room-temperature gaseous air, which is ready to be transferred to the low-temperature storage and heat exchange integrated device (200) for further processing.
3. A liquid air energy storage system based on an alternating operation cryogenic storage and heat exchange integrated device according to claim 2, characterized in that, The air expansion subsystem (700) includes a first heater (701), a first expander (702), a second heater (703), a second expander (704), a third heater (705), a third expander (706), a fourth heater (707), and a fourth expander (708). The air output terminal of the first heater (701) is connected to the input terminal of the first expander (702), and the output terminal of the first expander (702) is connected to the air input terminal of the second heater (703); the air output terminal of the second heater (703) is connected to the input terminal of the second expander (704), and the output terminal of the second expander (704) is connected to the air input terminal of the third heater (705); the air output terminal of the third heater (705) is connected to the input terminal of the third expander (706), and the output terminal of the third expander (706) is connected to the air input terminal of the fourth heater (707); the air output terminal of the fourth heater (707) is connected to the input terminal of the fourth expander (708), and the output terminal of the fourth expander (708) discharges exhaust gas into the environment; The air expansion subsystem (700) is used to further heat and expand the high-pressure gaseous air from the cryogenic storage and heat exchange integrated device (200). The expanded air expander does work to drive the generator to generate electricity. Finally, the last stage expander discharges air at ambient pressure, completing the power generation process.
4. A liquid air energy storage system based on an alternating operation cryogenic storage and heat exchange integrated device according to claim 3, characterized in that, The thermal storage subsystem (600) includes a normal temperature water tank (601), a hot water tank (602), a first water supply pump (603), a second water supply pump (604), and a radiator (605). The output end of the ambient temperature water tank (601) is connected to the water input ends of the first cooler (102), the second cooler (104), the third cooler (108), and the fourth cooler (110) respectively via the first water supply pump (603). The water output ends of the first cooler (102), the second cooler (104), the third cooler (108), and the fourth cooler (110) are all connected to the input end of the hot water tank (602). The output end of the hot water tank (602) is connected to the water input ends of the first heater (701), the second heater (703), the third heater (705), and the fourth heater (707) respectively via the second water supply pump (604). The water output ends of the first heater (701), the second heater (703), the third heater (705), and the fourth heater (707) are connected to the input end of the room temperature water tank (601) via the radiator (605). The thermal storage subsystem (600) drives water circulation through the first water supply pump (603) and the second water supply pump (604), so that when the cold water in the ambient temperature water tank (601) flows through the heat exchanger of the air compression subsystem (100), it carries away the heat generated during air compression and stores it in the hot water tank (602). This heat is then used to provide heat to the air used for expansion and power generation through the first heater (701), the second heater (703), the third heater (705), and the fourth heater (707), enabling it to generate more electricity. When the hot water in the hot water tank (602) flows through the first heater (701), second heater (703), third heater (705), and fourth heater (707) of the air expansion subsystem (700), it carries away the cooling energy generated during air expansion and stores it in the ambient temperature water tank (601). The cooling energy is then utilized in the air compression process through the first cooler (102), second cooler (104), third cooler (108), and fourth cooler (110), thereby improving the liquefaction rate and overall efficiency of the system.
5. A liquid air energy storage system based on an alternating operation cryogenic storage and heat exchange integrated device according to claim 4, characterized in that, The cryogenic storage and heat exchange integrated device (200) includes a first reversing three-way control valve (201), a second reversing three-way control valve (202), a third reversing three-way control valve (203), a fourth reversing three-way control valve (204), a fifth reversing three-way control valve (205), a first cold storage filling bed (206), a second cold storage filling bed (207), a third cold storage filling bed (208), a fourth cold storage filling bed (209), a first switching valve (210), a second switching valve (211), a third switching valve (212), a sixth reversing three-way control valve (213), a seventh reversing three-way control valve (214), an eighth reversing three-way control valve (215), a ninth reversing three-way control valve (216), and a tenth reversing three-way control valve (217). Energy storage mode 1: The air output end of the fourth cooler (110) is divided into two streams after passing through the first reversing three-way control valve (201). Each stream is connected to the upper input end of the first cold storage bed (206) and the second cold storage bed (207) through the second reversing three-way control valve (202) and the third reversing three-way control valve (203). The lower output ends of the first cold storage bed (206) and the second cold storage bed (207) are merged into one stream through the sixth reversing three-way control valve (213) and the seventh reversing three-way control valve (214), and then connected to the input end of the low temperature storage tank (400) through the tenth reversing three-way control valve (217) and the low temperature throttle valve (300). The output end of the cryogenic storage tank (400) is connected to the lower input ends of the third cold storage bed (208) and the fourth cold storage bed (209) through the eighth reversing three-way control valve (215) and the ninth reversing three-way control valve (216), respectively. The upper output ends of the third cold storage bed (208) and the fourth cold storage bed (209) are connected to the air input end of the third compressor (107) through the fourth reversing three-way control valve (204) and the fifth reversing three-way control valve (205), respectively. Energy storage mode 2: The air output end of the fourth cooler (110) is divided into two streams after passing through the first reversing three-way control valve (201). Each stream is connected to the upper input end of the third cold storage bed (208) and the fourth cold storage bed (209) through the fourth reversing three-way control valve (204) and the fifth reversing three-way control valve (205). The lower output ends of the third cold storage bed (208) and the fourth cold storage bed (209) are merged into one stream through the eighth reversing three-way control valve (215) and the ninth reversing three-way control valve (216), and then connected to the input end of the low temperature storage tank (400) through the tenth reversing three-way control valve (217) and the low temperature throttle valve (300). The output end of the cryogenic storage tank (400) is connected to the lower input ends of the first cold storage bed (206) and the second cold storage bed (207) through the sixth reversing three-way control valve (213) and the seventh reversing three-way control valve (214), respectively; the upper output ends of the first cold storage bed (206) and the second cold storage bed (207) are connected to the air input end of the third compressor (107) through the second reversing three-way control valve (202) and the third reversing three-way control valve (203), respectively. Discharge mode: The output end of the cryogenic storage tank (400) is connected to the lower input end of the fourth cold storage bed (209) in sequence through the liquid air pump (500), the tenth reversing three-way control valve (217), and the ninth reversing three-way control valve (216). The upper output end of the fourth cold storage bed (209) is connected to the lower input end of the third cold storage bed (208) through the third switching valve (212). The upper output end of the third cold storage bed (208) is connected to the lower input end of the second cold storage bed (207) through the second switching valve (211). The upper output end of the second cold storage bed (207) is connected to the lower input end of the first cold storage bed (206) through the first switching valve (210). The upper output end of the first cold storage bed (206) is connected to the first heater (701) in sequence through the second reversing three-way control valve (202) and the first reversing three-way control valve (201). The integrated low-temperature storage and heat exchange device (200) creates different circuits between the cold storage and heat exchange beds by controlling the three-way control valve and the switching valve.