Liquid air energy storage system and liquid air energy storage method

Abstract

The embodiment of the present application provides a liquid air energy storage system and a liquid air energy storage method, wherein the liquid air energy storage system includes: an air compressor, a cooler group, an air throttling device, a gas-liquid separator, a liquid air storage tank, a first refrigeration compressor and a first refrigeration throttling device; the cooler group has a first cooling channel, a second cooling channel, a third cooling channel and a first refrigerant channel, the input end of the third cooling channel is used to connect to the output end of the cold storage medium tank, and the output end of the third cooling channel is used to connect to the input end of the hot storage medium tank; the input end of the first refrigerant channel is connected to the output end of the first refrigeration throttling device, and the output end of the first refrigerant channel is connected to the input end of the first refrigeration compressor; the output end of the first refrigeration compressor is connected to the input end of the first refrigeration throttling device. The technical solution of the embodiment of the present application can make the cold source of the system more diverse, which is conducive to the stable operation of the system under different loads.

Description

Technical Field

[0001] The present application relates to the field of liquid air energy storage technology, and in particular to a liquid air energy storage system and a liquid air energy storage method. Background Art

[0002] In related technologies, liquid air energy storage systems rely on a fixed, single cooling source for air liquefaction, resulting in a low air liquefaction rate and thus affecting system efficiency. Furthermore, due to the system's limited cooling capacity, it is unable to provide additional cooling capacity when the storage duration needs to be increased, significantly reducing the system's workload range and hindering variable load operation. Summary of the Invention

[0003] The embodiments of the present application provide a liquid air energy storage system and a liquid air energy storage method to solve or alleviate one or more technical problems in the prior art.

[0004] As one aspect of an embodiment of the present application, an embodiment of the present application provides a liquid air energy storage system, comprising: an air compressor, a cooler group, an air throttling device, a gas-liquid separator, a liquid air storage tank, a first refrigeration compressor and a first refrigeration throttling device; wherein, the input end of the gas-liquid separator is connected to the output end of the air throttling device; the liquid output end of the gas-liquid separator is connected to the input end of the liquid air storage tank; the cooler group has a first cooling channel, a second cooling channel, a third cooling channel and a first refrigerant channel, the input end of the first cooling channel is connected to the output end of the air compressor, and the output end of the first cooling channel is connected to the input end of the air throttling device; the input end of the second cooling channel is connected to the gaseous output end of the gas-liquid separator; the input end of the third cooling channel is used to connect to the output end of the cold tank of the cold storage medium, and the output end of the third cooling channel is used to connect to the input end of the hot tank of the cold storage medium; the input end of the first refrigerant channel is connected to the output end of the first refrigeration throttling device, and the output end of the first refrigerant channel is connected to the input end of the first refrigeration compressor; the output end of the first refrigeration compressor is connected to the input end of the first refrigeration throttling device.

[0005] In one embodiment, the cooler group includes a plurality of coolers, each cooler including a first sub-channel, a second sub-channel and a third sub-channel; wherein the first cooling channel is formed by connecting the first sub-channels of each cooler in series; the second cooling channel is formed by connecting the second sub-channels of each cooler in series; the third cooling channel is formed by connecting the third sub-channels of each cooler in series; and the first refrigerant channel is provided in at least one cooler.

[0006] In one embodiment, the plurality of coolers include a first cooler, a second cooler, and a third cooler, and the first refrigerant passage is provided in one of the first cooler, the second cooler, and the third cooler.

[0007] In one embodiment, the first cooler is connected between the air compressor and the second cooler, the third cooler is connected between the air throttling device and the second cooler; and the first refrigerant channel is provided in the first cooler.

[0008] In one embodiment, the first cooler and the second cooler both include a second refrigerant channel; the liquid air energy storage system also includes: a second refrigeration compressor, the input end of the second refrigeration compressor is connected to the output end of the second refrigerant channel of the second cooler, and the output end of the second refrigeration compressor is connected to the input end of the second refrigerant channel of the first cooler; a second refrigeration throttling device, connected between the second refrigerant channel of the first cooler and the second refrigerant channel of the second cooler.

[0009] In one embodiment, the first cooler, the second cooler and the third cooler all include a third refrigerant channel; the liquid air energy storage system also includes: a third refrigeration compressor, the input end of the third refrigeration compressor is connected to the output end of the third refrigerant channel of the third cooler, and the output end of the third refrigeration compressor is connected to the input end of the third refrigerant channel of the first cooler; a third refrigeration throttling device, connected between the third refrigerant channel of the second cooler and the third refrigerant channel of the third cooler.

[0010] In one embodiment, the liquid air energy storage system also includes: a heat storage heat exchanger having a first heat storage channel and a second heat storage channel, the input end of the first heat storage channel is connected to the output end of the first refrigeration compressor, and the output end of the first heat storage channel is connected to the input end of the first refrigeration throttling device; the input end of the second heat storage channel is used to connect to the output end of the heat storage medium cold tank, and the output end of the second heat storage channel is used to connect to the input end of the heat storage medium hot tank.

[0011] In one embodiment, the liquid air energy storage system also includes: a cold storage heat exchanger, having a first cold storage channel and a second cold storage channel, the input end of the first cold storage channel is connected to the output end of the liquid air storage tank, the input end of the second cold storage channel is used to connect to the output end of the cold storage medium hot tank, and the output end of the second cold storage channel is used to connect to the input end of the cold storage medium cold tank; a heating heat exchanger, having a first heat exchange channel and a second heat exchange channel, the input end of the first heat exchange channel is connected to the output end of the first cold storage channel, the input end of the second heat exchange channel is connected to the output end of the hot storage medium tank, and the output end of the second heat exchange channel is connected to the input end of the cold storage medium tank; an air expander, connected to the output end of the first heat exchange channel.

[0012] In one embodiment, the liquid air energy storage system further includes: a booster pump connected between the liquid air storage tank and the cold storage heat exchanger.

[0013] As one aspect of an embodiment of the present application, an embodiment of the present application provides a liquid air energy storage method, which is based on the liquid air energy storage system of any of the above-mentioned embodiments, and the method includes: causing the output end of the cold storage medium cold tank to output the cold storage medium to the third cooling channel of the cooler group; causing the gaseous output end of the gas-liquid separator to output low-temperature air to the second cooling channel of the cooler group; using a first refrigeration compressor to compress the first refrigerant, and throttling the compressed first refrigerant through a first refrigeration throttling device, so that the output end of the first refrigeration throttling device outputs low-temperature refrigerant to the first refrigerant channel of the cooler group; using an air compressor to compress air, so that the output end of the air compressor outputs high-pressure air to the first cooling channel of the cooler group, so that the high-pressure air input into the first cooling channel exchanges heat with the low-temperature air in the second cooling channel, the cold storage medium in the third cooling channel, and the low-temperature refrigerant in the first refrigerant channel to form liquid air; using the air throttling device to throttle the liquid air output from the first cooling channel to form gas-liquid two-phase air; using a gas-liquid separator to separate the gas-liquid two-phase air, and storing the separated liquid air in a liquid air storage tank.

[0014] The embodiment of the present application adopts the above-mentioned technical solution to solve the problem of insufficient cooling capacity of the cold storage medium, so that the low-temperature air in the second cooling channel, the cold storage medium in the third cooling channel, and the low-temperature refrigerant in the first refrigerant channel can all provide cooling energy, making the cold source of the system more diverse, which is conducive to the stable operation of the system under different loads, can expand the operating time range of the system, improve the flexibility, stability and safety of the system, and at the same time can improve the air liquefaction rate of the system.

[0015] The above summary is for illustrative purposes only and is not intended to be limiting in any way. In addition to the illustrative aspects, embodiments and features described above, further aspects, embodiments and features of the present application will be readily apparent by reference to the accompanying drawings and the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In the accompanying drawings, unless otherwise specified, the same reference numerals throughout the multiple drawings represent the same or similar components or elements. These drawings are not necessarily drawn to scale. It should be understood that these drawings only depict some embodiments disclosed in this application and should not be construed as limiting the scope of this application.

[0017] Figure 1 A schematic structural diagram of a liquid air energy storage system according to an embodiment of the present application is shown;

[0018] Figure 2 A schematic flow chart of a liquid air energy storage method according to an embodiment of the present application is shown.

[0019] Description of reference numerals:

[0020] 10: Liquid air energy storage system; 100: Air compressor; 200: Cooler group; 200a: First cooling channel; 200b: Second cooling channel; 200c: Third cooling channel; 200d: First refrigerant channel; 210: First cooler; 211: First sub-channel; 212: Second sub-channel; 213: Third sub-channel; 214: Second refrigerant channel; 215: Third refrigerant channel; 220: Second cooler; 230: Third cooler; 300: Air throttling device; 400: Gas-liquid separator; 500: Liquid air storage tank; 600: First refrigeration compressor; 700: First refrigeration Flow device; 800: cold storage medium tank; 900: hot storage medium tank; 10e: second refrigeration compressor; 10f: second refrigeration throttling device; 10g: third refrigeration compressor; 10h: third refrigeration throttling device; 10i: heat storage heat exchanger; 110i: first heat storage channel; 120i: second heat storage channel; 10j: cold storage medium tank; 10k: hot storage medium tank; 10m: cold storage heat exchanger; 110m: first cold storage channel; 120m: second cold storage channel; 10n: heating heat exchanger; 110n: first heat exchange channel; 120n: second heat exchange channel; 10p: air expander; 10q: booster pump. DETAILED DESCRIPTION

[0021] Hereinafter, only certain exemplary embodiments are briefly described. As will be appreciated by those skilled in the art, the described embodiments may be modified in various ways without departing from the spirit or scope of the present application. Therefore, the drawings and description are to be regarded as illustrative in nature and not restrictive.

[0022] Driven by the rise of clean energy and the development of renewable energy, energy storage technology has become a focal point in today's energy industry. Liquid air energy storage (LAES) has garnered significant attention as an advanced energy storage solution. LAS utilizes the properties of liquid air to store energy, converting electrical energy into potential energy that can be released to generate electricity when needed, thus supporting the balance and stability of the power system.

[0023] Growing concerns about climate change and environmental protection are accelerating the promotion and application of clean energy technologies to reduce reliance on traditional fossil fuels. The volatility and intermittency of renewable energy sources, such as wind and solar, pose challenges to grid operations. Therefore, energy storage technology has become a key tool for addressing renewable energy consumption, improving grid flexibility, and enhancing overall energy efficiency.

[0024] The emergence of liquid air energy storage technology fills the gaps in traditional energy storage technologies. Its environmentally friendly, efficient, and safe characteristics make it a highly anticipated energy storage solution. Against the backdrop of the continued advancement of clean energy technologies, liquid air energy storage technology is expected to play an even more important role in the future, becoming a key component of future clean energy systems. This will further promote the popularization and application of clean energy, facilitate the goal of a low-carbon economy and sustainable development, and help promote energy transformation and sustainable development.

[0025] However, current liquid air energy storage systems rely on a fixed, single cooling source for air liquefaction, primarily the cooling capacity of the liquid air stored in the energy release unit. This results in a low air liquefaction rate, which impacts system efficiency. Furthermore, due to the limited cooling capacity of the system, when the storage duration needs to be increased, the system is unable to provide additional cooling capacity, significantly reducing the system's workload range and hindering variable load operation.

[0026] To solve the above problems, the first embodiment of the present application provides a liquid air energy storage system. Figure 1 FIG. 1 shows a schematic structural diagram of a liquid air energy storage system 10 according to an embodiment of the present application. Figure 1 As shown, the liquid air energy storage system 10 includes an air compressor 100, a cooler group 200, an air throttling device 300, a gas-liquid separator 400, a liquid air storage tank 500, a first refrigeration compressor 600 and a first refrigeration throttling device 700.

[0027] Specifically, the input of the gas-liquid separator 400 is connected to the output of the air throttling device 300. The liquid output of the gas-liquid separator 400 is connected to the input of the liquid air storage tank 500. The cooler assembly 200 comprises a first cooling channel 200a, a second cooling channel 200b, a third cooling channel 200c, and a first refrigerant channel 200d. The input of the first cooling channel 200a is connected to the output of the air compressor 100, and the output of the first cooling channel 200a is connected to the input of the air throttling device 300. The input of the second cooling channel 200b is connected to the gas output of the gas-liquid separator 400. The input of the third cooling channel 200c is connected to the output of the cold storage medium tank 800, and the output of the third cooling channel 200c is connected to the input of the hot storage medium tank 900. The input end of the first refrigerant channel 200d is connected to the output end of the first refrigeration throttling device 700 , and the output end of the first refrigerant channel 200d is connected to the input end of the first refrigeration compressor 600 . The output end of the first refrigeration compressor 600 is connected to the input end of the first refrigeration throttling device 700 .

[0028] Combine Figure 1The output end of the cold storage medium tank 800 outputs cold storage medium to the third cooling channel 200c of the cooler assembly 200. The gaseous output end of the gas-liquid separator 400 can output low-temperature air to the second cooling channel 200b of the cooler assembly 200. When the first refrigeration compressor 600 is operating, it can compress the first refrigerant. The compressed first refrigerant can then be throttled, cooled, and pressure-reduced by the first refrigeration throttling device 700 to form a low-temperature refrigerant. The low-temperature refrigerant is then input from the output end of the first refrigeration throttling device 700 into the first refrigerant channel 200d of the cooler assembly 200. The first refrigeration compressor 600, the first refrigeration throttling device 700, and the first refrigerant channel 200d together form a first refrigeration cycle. The cooling capacity provided by the first refrigerant can be varied by changing the flow rate or operating parameters of the first refrigerant in the first refrigeration cycle.

[0029] The liquid air energy storage system 10 can have an energy storage phase and an energy release phase. The liquid air energy storage system 10 is in the energy storage phase during the low electricity demand period and in the energy release phase during the peak electricity demand period to generate electricity. In the energy storage phase, the electricity in the power grid drives the air compressor 100 to work, causing the air compressor 100 to compress the air and output normal temperature and high-pressure air to the first cooling channel 200a of the cooler group 200. The high-pressure air input into the first cooling channel 200a can exchange heat with the low-temperature air in the second cooling channel 200b, the cold storage medium in the third cooling channel 200c, and the low-temperature refrigerant in the first refrigerant channel 200d, absorbing the cold energy of the low-temperature air in the second cooling channel 200b, the cold energy of the cold storage medium in the third cooling channel 200c, and the cold energy of the low-temperature refrigerant in the first refrigerant channel 200d, thereby forming liquid air. The liquid air flows through the air throttling device 300 to throttle, reduce temperature and pressure, and form gas-liquid two-phase air. The gas-liquid two-phase air is input into the gas-liquid separator 400 from the air throttling device 300 . The gas-liquid separator 400 can separate the gas-liquid two-phase air and store the separated liquid air in the liquid air storage tank 500 .

[0030] For example, the flow rate of low-temperature air output by the gas-liquid separator 400 to the second cooling channel 200b is relatively small, and the main cold source for air liquefaction is the cold storage medium output by the cold storage medium cold tank 800. When the duration of the low power demand period increases (for example, from 4 hours to 4.5 hours), the energy storage duration of the liquid air energy storage system 10 increases, and additional cooling capacity is required to liquefy the air. At this time, the first refrigeration compressor 600 can be operated to compress the first refrigerant. The compressed first refrigerant can be throttled, cooled, and reduced in pressure by the first refrigeration throttling device 700 to form a low-temperature refrigerant. The low-temperature refrigerant is input into the first refrigerant channel 200d of the cooler group 200 from the output end of the first refrigeration throttling device 700. The room-temperature, high-pressure air input into the first cooling channel 200a can absorb the cold energy of the low-temperature refrigerant in the first refrigerant channel 200d to form liquid air.

[0031] For example, when the cold storage medium in the cold storage medium tank 800 is insufficient due to factors such as equipment maintenance, additional cooling capacity is also required to liquefy the air. At this time, the first refrigeration compressor 600 can also be operated to compress the first refrigerant. The compressed first refrigerant can be throttled, cooled, and reduced in pressure by the first refrigeration throttling device 700 to form a low-temperature refrigerant. The low-temperature refrigerant is input into the first refrigerant channel 200d of the cooler group 200 from the output end of the first refrigeration throttling device 700. The high-pressure air input into the first cooling channel 200a can absorb the cold energy of the low-temperature refrigerant in the first refrigerant channel 200d to form liquid air.

[0032] For example, the liquid air energy storage system 10 can be installed near clean energy power stations to more efficiently manage peak loads, alleviate pressure on power plant equipment, and address the volatility of renewable energy. Furthermore, by supplementing the cooling source for the air liquefaction process, the system's stability and operational flexibility can be effectively improved.

[0033] According to the liquid air energy storage system 10 of the embodiment of the present application, by setting a first refrigeration compressor 600 and a first refrigeration throttling device 700, and making the cooler group 200 have a first cooling channel 200a, a second cooling channel 200b, a third cooling channel 200c and a first refrigerant channel 200d, when the energy storage time of the system increases, additional cooling capacity can be obtained by operating the first refrigeration compressor 600, thereby solving the problem of insufficient cooling capacity of the cold storage medium, so that the low-temperature air in the second cooling channel 200b, the cold storage medium in the third cooling channel 200c and the low-temperature refrigerant in the first refrigerant channel 200d can all provide cooling energy, making the cold source of the system more diverse, which is conducive to the stable operation of the system under different loads, can expand the operating time range of the system, improve the flexibility, stability and safety of the system, and at the same time can improve the air liquefaction rate of the system.

[0034] In one embodiment, Figure 1 As shown, cooler group 200 includes multiple coolers, each of which includes a first sub-channel 211, a second sub-channel 212, and a third sub-channel 213. Specifically, first cooling channel 200a is formed by connecting the first sub-channels 211 of each cooler in series; second cooling channel 200b is formed by connecting the second sub-channels 212 of each cooler in series; and third cooling channel 200c is formed by connecting the third sub-channels 213 of each cooler in series. First refrigerant channel 200d is provided in at least one cooler. In the description of this application, "multiple" means two or more.

[0035] For example, in Figure 1 In the example shown in FIG. 1 , the cooler group 200 includes three coolers, namely a first cooler 210, a second cooler 220, and a third cooler 230. Each of the first cooler 210, the second cooler 220, and the third cooler 230 includes a first sub-channel 211, a second sub-channel 212, and a third sub-channel 213. A first cooling channel 200a is formed by connecting the first sub-channel 211 of the first cooler 210, the first sub-channel 211 of the second cooler 220, and the first sub-channel 211 of the third cooler 230 in series. A second cooling channel 200b is formed by connecting the second sub-channel 212 of the first cooler 210, the second sub-channel 212 of the second cooler 220, and the second sub-channel 212 of the third cooler 230 in series. A third cooling channel 200c is formed by connecting the third sub-channel 213 of the first cooler 210, the third sub-channel 213 of the second cooler 220, and the third sub-channel 213 of the third cooler 230 in series. The first refrigerant passage 200 d may be provided in at least one of the first cooler 210 , the second cooler 220 , and the third cooler 230 .

[0036] In this embodiment, the cooler group 200 includes multiple coolers, and the first cooling channel 200a is formed in series by the first sub-channels 211 of each cooler, the second cooling channel 200b is formed in series by the second sub-channels 212 of each cooler, and the third cooling channel 200c is formed in series by the third sub-channels 213 of each cooler. The lengths of the first cooling channel 200a, the second cooling channel 200b and the third cooling channel 200c are relatively long. The temperature of the air can be gradually reduced in the process of flowing through the first sub-channels 211 of each cooler, so that the heat exchange between the air in the first cooling channel 200a and the low-temperature air in the second cooling channel 200b is more sufficient, and the heat exchange between the air in the first cooling channel 200a and the cold storage medium in the third cooling channel 200c is more sufficient, thereby improving the cooling efficiency of the air and making it easier to achieve air liquefaction.

[0037] Figure 1 Three coolers are shown for illustrative purposes, but after reading the technical solution of this application, ordinary technicians can obviously understand that the solution can be applied to technical solutions with other numbers of coolers, which also falls within the scope of protection of this application.

[0038] In one embodiment, reference Figure 1 The multiple coolers may include a first cooler 210, a second cooler 220, and a third cooler 230, and the first refrigerant channel 200d is provided in one of the first cooler 210, the second cooler 220, and the third cooler 230. In this way, the structure of the liquid air energy storage system 10 can be simplified, the complexity of the system can be reduced, and the number of devices in the first refrigeration cycle where the first refrigerant channel 200d is located can be reduced, thereby facilitating maintenance and management.

[0039] In one embodiment, combined Figure 1 The first cooler 210 is connected between the air compressor 100 and the second cooler 220 , and the third cooler 230 is connected between the air throttling device 300 and the second cooler 220 ; the first refrigerant channel 200d is provided in the first cooler 210 .

[0040] For example, in Figure 1In the example, the cold storage medium is output from the output end of the cold storage medium tank 800 and flows sequentially through the third subchannel 213 of the third cooler 230, the third subchannel 213 of the second cooler 220, and the third subchannel 213 of the first cooler 210 before being input into the hot storage medium tank 900. Low-temperature air is output from the gaseous output end of the gas-liquid separator 400 and flows sequentially through the second subchannel 212 of the third cooler 230, the second subchannel 212 of the second cooler 220, and the second subchannel 212 of the first cooler 210. When the first refrigeration compressor 600 is operating, it compresses the first refrigerant. The compressed first refrigerant is throttled, cooled, and reduced in pressure by the first refrigeration throttling device 700 to form low-temperature refrigerant. The low-temperature refrigerant is then input into the first refrigerant channel 200d from the output end of the first refrigeration throttling device 700.

[0041] During the energy storage phase, the air compressor 100 compresses air, which then flows sequentially through the first subchannel 211 of the first cooler 210, the first subchannel 211 of the second cooler 220, and the first subchannel 211 of the third cooler 230. The air flowing through the first subchannel 211 of the first cooler 210 absorbs the cold energy of the cold storage medium in the third subchannel 213 of the first cooler 210, the cold energy of the low-temperature air in the second subchannel 212 of the first cooler 210, and the cold energy of the low-temperature refrigerant in the first refrigerant channel 200d. The air flowing through the first subchannel 211 of the second cooler 220 absorbs the cold energy of the cold storage medium in the third subchannel 213 of the second cooler 220 and the cold energy of the low-temperature air in the second subchannel 212 of the second cooler 220. The air flowing through the first subchannel 211 of the third cooler 230 absorbs the cold energy of the cold storage medium in the third subchannel 213 of the third cooler 230 and the cold energy of the low-temperature air in the second subchannel 212 of the third cooler 230. The air output from the first subchannel 211 of the third cooler 230 is liquid air. The liquid air flows through the air throttling device 300 for throttling, cooling, and pressure reduction, forming gas-liquid two-phase air. The gas-liquid two-phase air is input from the air throttling device 300 into the gas-liquid separator 400, which separates the gas-liquid two-phase air and stores the separated liquid air in the liquid air storage tank 500.

[0042] In one embodiment, Figure 1As shown, the first cooler 210 and the second cooler 220 each include a second refrigerant channel 214. The liquid air energy storage system 10 may further include a second refrigeration compressor 10e and a second refrigeration throttling device 10f. The input end of the second refrigeration compressor 10e is connected to the output end of the second refrigerant channel 214 of the second cooler 220, and the output end of the second refrigeration compressor 10e is connected to the input end of the second refrigerant channel 214 of the first cooler 210. The second refrigeration throttling device 10f is connected between the second refrigerant channel 214 of the first cooler 210 and the second refrigerant channel 214 of the second cooler 220.

[0043] For example, when the second refrigeration compressor 10e is operating, the second refrigeration compressor 10e can compress the second refrigerant. The compressed second refrigerant enters the second refrigerant channel 214 of the first cooler 210 and is cooled by the first cooler 210. The second refrigerant then passes through the second refrigeration throttling device 10f, where it is throttled, cooled, and reduced in pressure. From the output end of the second refrigeration throttling device 10f, the second refrigerant is input into the second refrigerant channel 214 of the second cooler 220, releasing cooling energy to the second cooler 220. This allows the air flowing through the first sub-channel 211 of the second cooler 220 to absorb the cooling energy released by the second refrigerant. The second refrigerant output from the second refrigerant channel 214 of the second cooler 220 returns to the second refrigeration compressor 10e from the input end.

[0044] In this embodiment, the second refrigeration compressor 10e, the second refrigerant channel 214 of the first cooler 210, the second refrigeration throttling device 10f, and the second refrigerant channel 214 of the second cooler 220 can collectively form a second refrigeration cycle. The cooling capacity provided by the second refrigerant can be changed by changing the flow rate or operating parameters of the second refrigerant in the second refrigeration cycle. Moreover, the second refrigeration cycle and the first refrigeration cycle are independently provided. Compared to the cooling capacity provided by the first refrigerant in the first refrigeration cycle, the cooling capacity provided by the second refrigerant in the second refrigeration cycle is greater, thereby realizing a multi-stage refrigeration cycle and providing a stepped cooling capacity for air liquefaction to meet the needs of air liquefaction.

[0045] In one embodiment, reference Figure 1, the first cooler 210, the second cooler 220 and the third cooler 230 all include a third refrigerant channel 215. The liquid air energy storage system 10 may further include a third refrigeration compressor 10g and a third refrigeration throttling device 10h. Specifically, the input end of the third refrigeration compressor 10g is connected to the output end of the third refrigerant channel 215 of the third cooler 230, and the output end of the third refrigeration compressor 10g is connected to the input end of the third refrigerant channel 215 of the first cooler 210. The third refrigeration throttling device 10h is connected between the third refrigerant channel 215 of the second cooler 220 and the third refrigerant channel 215 of the third cooler 230.

[0046] For example, in Figure 1 In the example, the third refrigerant channel 215 of the second cooler 220 is connected between the third refrigerant channel 215 of the first cooler 210 and the third refrigerant channel 215 of the third cooler 230. When the third refrigeration compressor 10g is operating, the third refrigeration compressor 10g can compress the third refrigerant. The compressed third refrigerant flows sequentially through the third refrigerant channel 215 of the first cooler 210 and the third refrigerant channel 215 of the second cooler 220, thereby being cooled by the first cooler 210 and the second cooler 220. The third refrigerant then passes through the third refrigeration throttling device 10h, where it is throttled, cooled, and reduced in pressure. It is then fed from the output end of the third refrigeration throttling device 10h into the third refrigerant channel 215 of the third cooler 230, releasing cooling energy to the third cooler 230. The air flowing through the first sub-channel 211 of the third cooler 230 can absorb the cooling energy released by the third refrigerant. The third refrigerant output from the third refrigerant passage 215 of the third cooler 230 returns to the third refrigeration compressor 10g from the input end of the third refrigeration compressor 10g.

[0047] The third refrigeration compressor 10g, the third refrigerant channel 215 of the first cooler 210, the third refrigerant channel 215 of the second cooler 220, the third refrigeration throttling device 10h, and the third refrigerant channel 215 of the third cooler 230 can collectively form a third refrigeration cycle. The cooling energy released by the third refrigerant in the third refrigeration cycle is high-quality cooling energy. The cooling energy released by the second refrigerant in the second refrigeration cycle is medium-quality cooling energy, while the cooling energy released by the first refrigerant in the first refrigeration cycle is low-quality cooling energy. Compared to the cooling energy provided by the second refrigerant in the second refrigeration cycle, the cooling energy provided by the third refrigerant in the third refrigeration cycle is greater.

[0048] In this embodiment, the cooling capacity provided by the third refrigerant can be varied by changing the flow rate or operating parameters of the third refrigerant in the third refrigeration cycle. Furthermore, the third refrigeration cycle is independently provided from the first refrigeration cycle. Compared to the cooling capacity provided by the first refrigerant in the first refrigeration cycle, the cooling capacity provided by the third refrigerant in the third refrigeration cycle is greater, thereby enabling a multi-stage (e.g., three-stage) refrigeration cycle, providing a stepped cooling capacity for air liquefaction to meet air liquefaction requirements.

[0049] In one embodiment, combined Figure 1 The liquid air energy storage system 10 may further include a heat storage heat exchanger 10i. The heat storage heat exchanger 10i has a first heat storage channel 110i and a second heat storage channel 120i. The input of the first heat storage channel 110i is connected to the output of the first refrigeration compressor 600, and the output of the first heat storage channel 110i is connected to the input of the first refrigeration throttling device 700. The input of the second heat storage channel 120i is used to connect to the output of the thermal storage medium cold tank 10j, and the output of the second heat storage channel 120i is used to connect to the input of the thermal storage medium hot tank 10k.

[0050] Illustratively, during the energy storage phase, the thermal storage medium is output from the thermal storage medium cold tank 10j, flows through the second thermal storage channel 120i of the thermal storage heat exchanger 10i, exchanges heat with the first refrigerant in the first thermal storage channel 110i, and is then input into the thermal storage medium hot tank 10k. The first refrigeration cycle also includes the first thermal storage channel 110i of the thermal storage heat exchanger 10i. When the first refrigeration compressor 600 is operating, the first refrigeration compressor 600 can compress the first refrigerant, and the compressed first refrigerant is input into the first thermal storage channel 110i of the thermal storage heat exchanger 10i. The first refrigerant in the first thermal storage channel 110i can exchange heat with the thermal storage medium flowing through the second thermal storage channel 120i, thereby transferring the compression heat to the thermal storage medium.

[0051] Optionally, the first refrigerant, the second refrigerant, the third refrigerant, the cold storage medium and the heat storage medium may be working media commonly used in the art, such as methane, ethane, ethylene, propane, Freon, etc., but not limited thereto.

[0052] In this embodiment, by providing a heat storage heat exchanger 10i having a first heat storage channel 110i and a second heat storage channel 120i, the compression heat of the first refrigerant can be utilized, thereby generating electricity by utilizing the heat of the heat storage medium during peak power demand periods.

[0053] In one embodiment, Figure 1As shown, the liquid air energy storage system 10 may further include a cold storage heat exchanger 10m, a heating heat exchanger 10n, and an air expander 10p. Specifically, the cold storage heat exchanger 10m has a first cold storage channel 110m and a second cold storage channel 120m. The input end of the first cold storage channel 110m is connected to the output end of the liquid air storage tank 500, the input end of the second cold storage channel 120m is used to connect to the output end of the cold storage medium hot tank 900, and the output end of the second cold storage channel 120m is used to connect to the input end of the cold storage medium cold tank 800. The heating heat exchanger 10n has a first heat exchange channel 110n and a second heat exchange channel 120n. The input end of the first heat exchange channel 110n is connected to the output end of the first cold storage channel 110m, the input end of the second heat exchange channel 120n is connected to the output end of the hot storage medium tank 10k, and the output end of the second heat exchange channel 120n is connected to the input end of the cold storage medium tank 10j. The air expander 10p is connected to the output end of the first heat exchange channel 110n.

[0054] Exemplarily, during the energy release phase, cold storage medium is discharged from the cold storage medium hot tank 900, flows through the second cold storage channel 120m of the cold storage heat exchanger 10m, exchanges heat with the air in the first cold storage channel 110m, and is then input into the cold storage medium cold tank 800. The cold storage medium is discharged from the hot storage medium tank 10k, flows through the second heat exchange channel 120n of the heating heat exchanger 10n, exchanges heat with the air in the first heat exchange channel 110n, and is then input into the cold storage medium cold tank 10j. Liquid air is discharged from the liquid air storage tank 500 and flows sequentially through the first cold storage channel 110m of the cold storage heat exchanger 10m and the first heat exchange channel 110n of the heating heat exchanger 10n. The air flowing through the first cold storage channel 110m can transfer cold energy to the cold storage medium, thereby reducing the temperature of the cold storage medium flowing through the second cold storage channel 120m. The air flowing through the first heat exchange channel 110n can absorb the heat of the heat storage medium in the second heat exchange channel 120n and finally generate electricity through the air expander 10p.

[0055] In this embodiment, by providing a cold storage heat exchanger 10m, a heating heat exchanger 10n and an air expander 10p, the liquid air output from the liquid air storage tank 500 can exchange heat with the cold storage medium in the second cold storage channel 120m and the heat storage medium in the second heat exchange channel 120n, respectively, thereby generating electricity through the air expander 10p, providing support for the balance and stability of the power system.

[0056] In one embodiment, reference Figure 1The liquid air energy storage system 10 may further include a booster pump 10q, which is connected between the liquid air storage tank 500 and the cold storage heat exchanger 10m. Thus, the booster pump 10q can increase the pressure of the liquid air output from the liquid air storage tank 500, thereby effectively exchanging heat with the cold storage medium in the second cold storage channel 120m and the heat storage medium in the second heat exchange channel 120n, and effectively releasing energy during the expansion process.

[0057] The second embodiment of the present application provides a liquid air energy storage method, which is based on the liquid air energy storage system of the first embodiment mentioned above. Figure 2 A schematic diagram of a liquid air energy storage method according to an embodiment of the present application is shown as follows: Figure 2 As shown, the method includes:

[0058] Step S201: The output end of the cold storage medium cold tank outputs the cold storage medium to the third cooling channel of the cooler group;

[0059] Step S202: enabling the gaseous output end of the gas-liquid separator to output low-temperature air to the second cooling channel of the cooler group;

[0060] Step S203: compressing the first refrigerant using the first refrigeration compressor, and throttling the compressed first refrigerant through the first refrigeration throttling device, so that the output end of the first refrigeration throttling device outputs low-temperature refrigerant to the first refrigerant channel of the cooler group.

[0061] For example, the first refrigeration compressor, the first refrigeration throttling device, and the first refrigerant channel may together form a first refrigeration cycle. The cooling capacity provided by the first refrigerant may be changed by changing the flow rate or operating parameters of the first refrigerant in the first refrigeration cycle.

[0062] Step S204: Compress the air using an air compressor so that the output end of the air compressor outputs high-pressure air to the first cooling channel of the cooler group, so that the high-pressure air input into the first cooling channel exchanges heat with the low-temperature air in the second cooling channel, the cold storage medium in the third cooling channel, and the low-temperature refrigerant in the first refrigerant channel to form liquid air.

[0063] It should be noted that the above-mentioned "low temperature" should be understood in a broad sense in this application, which means that compared with the air output from the output end of the air compressor, the temperature of the air output from the gaseous output end of the gas-liquid separator to the second cooling channel is lower, and the temperature of the first refrigerant output from the output end of the first refrigeration throttling device to the first refrigerant channel is lower.

[0064] Step S205: throttling the liquid air output from the first cooling channel by using an air throttling device to form gas-liquid two-phase air.

[0065] Step S206: Separate the gas-liquid two-phase air by using a gas-liquid separator, and store the separated liquid air in a liquid air storage tank.

[0066] Therefore, the high-pressure air input into the first cooling channel can absorb the cold energy of the low-temperature air in the second cooling channel, the cold energy of the cold storage medium in the third cooling channel, and the cold energy of the low-temperature refrigerant in the first refrigerant channel. When the energy storage time of the system increases, additional cooling capacity can be obtained by operating the first refrigeration compressor, which solves the problem of insufficient cooling capacity of the cold storage medium. The low-temperature air in the second cooling channel, the cold storage medium in the third cooling channel, and the low-temperature refrigerant in the first refrigerant channel can all provide cooling energy, making the cold source of the system more diverse, which is conducive to the stable operation of the system under different loads, improves the flexibility of the system, and at the same time can improve the air liquefaction rate of the system.

[0067] Other components of the liquid air energy storage system and the liquid air energy storage method of the above-mentioned embodiments can adopt various technical solutions known to ordinary technicians in this field now and in the future, and will not be described in detail here.

[0068] In the description of this specification, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on this application.

[0069] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or to implicitly indicate the quantity of the technical features indicated. Thus, features defined as "first" or "second" may explicitly or implicitly include one or more of the features.

[0070] In this application, unless otherwise expressly specified or limited, terms such as "installed," "connected," "connect," and "fixed" should be understood in a broad sense. For example, they may refer to fixed connection, detachable connection, or integration; mechanical connection, electrical connection, or communication; direct connection or indirect connection through an intermediate medium; and internal communication between two components or interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on specific circumstances.

[0071] In this application, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may include the first and second features being in direct contact, or may include the first and second features being in contact not directly but through another feature between them. Moreover, a first feature being "above," "above," and "above" a second feature includes the first feature being directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below," "below," and "below" a second feature includes the first feature being directly above and obliquely above the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0072] The disclosure above provides many different embodiments or examples for realizing different structures of the present application. In order to simplify the disclosure of the present application, the components and settings of specific examples are described above. Of course, they are merely examples and are not intended to limit the present application. In addition, the present application may repeat reference numbers and / or reference letters in different examples. Such repetition is for the purpose of simplicity and clarity and does not in itself indicate the relationship between the various embodiments and / or settings discussed.

[0073] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any person skilled in the art can easily conceive of various modifications or substitutions within the technical scope disclosed in this application, and such modifications or substitutions should be included in the scope of protection of the present application. Therefore, the scope of protection of the present application should be based on the scope of protection of the claims.

Claims

1. A liquid air energy storage system, characterized in that: It includes an air compressor, a cooler group, an air throttling device, a gas-liquid separator, a liquid air storage tank, a first refrigeration compressor and a first refrigeration throttling device; Wherein, the input end of the gas-liquid separator is connected to the output end of the air throttling device; the liquid output end of the gas-liquid separator is connected to the input end of the liquid air storage tank; the cooler group comprises a first cooling channel, a second cooling channel, a third cooling channel and a first refrigerant channel, the input end of the first cooling channel is connected to the output end of the air compressor, and the output end of the first cooling channel is connected to the input end of the air throttling device; the input end of the second cooling channel is connected to the gas output end of the gas-liquid separator; the input end of the third cooling channel is used to connect to the output end of the cold storage medium tank, and the output end of the third cooling channel is used to connect to the input end of the hot storage medium tank; The input end of the first refrigerant channel is connected to the output end of the first refrigeration throttling device, and the output end of the first refrigerant channel is connected to the input end of the first refrigeration compressor; the output end of the first refrigeration compressor is connected to the input end of the first refrigeration throttling device; The cooler group includes a plurality of coolers, each of which includes a first sub-channel, a second sub-channel and a third sub-channel; Wherein, the first cooling channel is formed by connecting the first sub-channels of each cooler in series; the second cooling channel is formed by connecting the second sub-channels of each cooler in series; the third cooling channel is formed by connecting the third sub-channels of each cooler in series; the first refrigerant channel is provided in at least one cooler; The plurality of coolers include a first cooler, a second cooler, and a third cooler, wherein the first refrigerant passage is provided in one of the first cooler, the second cooler, and the third cooler; The first cooler is connected between the air compressor and the second cooler, and the third cooler is connected between the air throttling device and the second cooler; the first refrigerant channel is provided in the first cooler; Among them, the temperature of the air can be gradually reduced in the process of flowing through the first sub-channel of each cooler, so that the air in the first cooling channel and the low-temperature air in the second cooling channel can exchange heat more fully, and the air in the first cooling channel and the cold storage medium in the third cooling channel can exchange heat more fully, thereby improving the cooling efficiency of the air and making it easier to achieve air liquefaction.

2. The liquid air energy storage system according to claim 1, characterized in that: The first cooler and the second cooler both include a second refrigerant channel; the liquid air energy storage system further includes: a second refrigeration compressor, wherein the input end of the second refrigeration compressor is connected to the output end of the second refrigerant channel of the second cooler, and the output end of the second refrigeration compressor is connected to the input end of the second refrigerant channel of the first cooler; The second refrigeration throttling device is connected between the second refrigerant channel of the first cooler and the second refrigerant channel of the second cooler.

3. The liquid air energy storage system according to claim 2, characterized in that: The first cooler, the second cooler, and the third cooler each include a third refrigerant channel; the liquid air energy storage system further includes: a third refrigeration compressor, wherein the input end of the third refrigeration compressor is connected to the output end of the third refrigerant channel of the third cooler, and the output end of the third refrigeration compressor is connected to the input end of the third refrigerant channel of the first cooler; The third refrigeration throttling device is connected between the third refrigerant channel of the second cooler and the third refrigerant channel of the third cooler.

4. The liquid air energy storage system according to any one of claims 1 to 3, characterized in that: Also includes: The heat storage heat exchanger has a first heat storage channel and a second heat storage channel, wherein the input end of the first heat storage channel is connected to the output end of the first refrigeration compressor, and the output end of the first heat storage channel is connected to the input end of the first refrigeration throttling device; the input end of the second heat storage channel is used to connect to the output end of the heat storage medium cold tank, and the output end of the second heat storage channel is used to connect to the input end of the heat storage medium hot tank.

5. The liquid air energy storage system according to claim 4, characterized in that: Also includes: The cold storage heat exchanger comprises a first cold storage channel and a second cold storage channel, wherein the input end of the first cold storage channel is connected to the output end of the liquid air storage tank, the input end of the second cold storage channel is used to connect to the output end of the cold storage medium hot tank, and the output end of the second cold storage channel is used to connect to the input end of the cold storage medium cold tank; The heating heat exchanger comprises a first heat exchange channel and a second heat exchange channel, wherein the input end of the first heat exchange channel is connected to the output end of the first cold storage channel, the input end of the second heat exchange channel is connected to the output end of the hot tank of the thermal storage medium, and the output end of the second heat exchange channel is connected to the input end of the cold tank of the thermal storage medium; An air expander is connected to the output end of the first heat exchange channel.

6. The liquid air energy storage system according to claim 5, characterized in that: Also includes: A booster pump is connected between the liquid air storage tank and the cold storage heat exchanger.

7. A liquid air energy storage method, characterized in that: The method is based on the liquid air energy storage system according to any one of claims 1 to 6, and the method comprises: The output end of the cold storage medium cold tank outputs the cold storage medium to the third cooling channel of the cooler group; The gaseous output end of the gas-liquid separator outputs low-temperature air to the second cooling channel of the cooler group; compressing a first refrigerant using a first refrigeration compressor, and throttling the compressed first refrigerant through a first refrigeration throttling device, so that an output end of the first refrigeration throttling device outputs low-temperature refrigerant to a first refrigerant channel of the cooler group; Compressing air using an air compressor so that an output end of the air compressor outputs high-pressure air to the first cooling channel of the cooler group, so that the high-pressure air input into the first cooling channel exchanges heat with the low-temperature air in the second cooling channel, the cold storage medium in the third cooling channel, and the low-temperature refrigerant in the first refrigerant channel, thereby forming liquid air; throttling the liquid air output from the first cooling channel by using an air throttling device to form gas-liquid two-phase air; A gas-liquid separator is used to separate the gas-liquid two-phase air, and the separated liquid air is stored in a liquid air storage tank.

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