Liquid air energy storage system and liquid air energy storage method

Abstract

The embodiment of the invention provides a liquid air energy storage system and a liquid air energy storage method.The liquid air energy storage system comprises an air compressor, a cooler set, 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 set is provided with 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 for being connected with the output end of the cold storage medium cold tank, and the output end of the third cooling channel is used for being connected with the input end of the cold storage medium hot 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. According to the technical scheme, cold sources of the system can be more diversified, and stable operation of the system under different loads is facilitated.

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 the related art, the cold source of the liquid air energy storage system is fixed and single in terms of air liquefaction, resulting in a low air liquefaction rate of the system, thus affecting the system efficiency. In addition, since the cold energy of the system is limited, when the energy storage time needs to be increased, the system cannot provide additional cold capacity, which greatly reduces the range of the system's workload, which is not conducive to the variable load operation of the system. 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, including: 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 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; and the first refrigerant channel is arranged 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 disposed 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 arranged 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 tank of the heat storage medium, and the output end of the second heat exchange channel is connected to the input end of the cold tank of the heat storage medium; 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 a 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, and forms liquid air; using an 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 cold 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 parts or elements. These drawings are not necessarily drawn to scale. It should be understood that these drawings only depict some embodiments disclosed in the present application and should not be regarded as limiting the scope of the present 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 tank of cold storage medium; 900: hot tank of cold storage medium; 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 tank of heat storage medium; 10k: hot tank of heat storage medium; 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] In the following, only some exemplary embodiments are briefly described. As those skilled in the art will appreciate, the described embodiments may be modified in various ways without departing from the spirit or scope of the present application. Therefore, the drawings and descriptions are considered to be exemplary and non-restrictive in nature.

[0022] Driven by the rise of clean energy and the development of renewable energy, energy storage technology has become one of the focuses of today's energy industry. Among them, liquid air energy storage technology has attracted much attention as an advanced energy storage solution. Liquid air energy storage technology uses the characteristics of liquid air to store energy, converting electrical energy into potential energy, and releasing it to generate electricity when needed, providing support for the balance and stability of the power system.

[0023] As concerns about climate change and environmental protection continue to grow, the promotion and application of clean energy technologies have been accelerated to reduce dependence on traditional fossil energy. Renewable energy sources such as wind and solar energy are volatile and intermittent, which poses challenges to the operation of the power grid. Therefore, energy storage technology has become one of the important means to solve the problem of renewable energy consumption, improve the flexibility of the power grid and the overall energy utilization rate.

[0024] The emergence of liquid air energy storage technology fills the gaps in traditional energy storage technology. Its environmental protection, high efficiency and safety make it a highly anticipated energy storage solution. In the context of continuously promoting the development of clean energy technology, liquid air energy storage technology is expected to play a more important role in the future and become an important part of the future clean energy system, further promoting the popularization and application of clean energy, promoting the realization of low-carbon economy and sustainable development goals, and helping to promote energy transformation and sustainable development.

[0025] However, the current liquid air energy storage system has a fixed and single cold source for air liquefaction, which is mainly composed of the cold energy of the liquid air stored in the energy release unit. On the one hand, the air liquefaction rate of the system is low, which affects the efficiency of the system; on the other hand, due to the limited cold energy of the system, when the energy storage time needs to be increased, the system cannot provide additional cold energy, which greatly reduces the range of the system's workload, which is not conducive to the variable load operation of the system.

[0026] In order to solve the above problems, a first embodiment of the present application provides a liquid air energy storage system. Figure 1 FIG. 1 is a schematic diagram showing the structure 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 end of the gas-liquid separator 400 is connected to the output end of the air throttling device 300. The liquid output end of the gas-liquid separator 400 is connected to the input end of the liquid air storage tank 500. The cooler group 200 has a first cooling channel 200a, a second cooling channel 200b, a third cooling channel 200c and a first refrigerant channel 200d. The input end of the first cooling channel 200a is connected to the output end of the air compressor 100, and the output end of the first cooling channel 200a is connected to the input end of the air throttling device 300. The input end of the second cooling channel 200b is connected to the gas output end of the gas-liquid separator 400. The input end of the third cooling channel 200c is used to connect to the output end of the cold storage medium tank 800, and the output end of the third cooling channel 200c is used to connect to the input end 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] Combination Figure 1, the output end of the cold storage medium cold tank 800 outputs the cold storage medium to the third cooling channel 200c of the cooler group 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 group 200. When the first refrigeration compressor 600 is working, the first refrigeration compressor 600 can compress the first refrigerant, and the compressed first refrigerant can be throttled, cooled and depressurized 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. At this time, the first refrigeration compressor 600, the first refrigeration throttling device 700 and the first refrigerant channel 200d can jointly form a first refrigeration cycle. The cooling capacity provided by the first refrigerant can be changed by changing the flow rate or working parameters of the first refrigerant in the first refrigeration cycle.

[0029] The liquid air energy storage system 10 may 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 power demand period, and is in the energy release phase during the peak power demand period to generate electricity. In the energy storage phase, the power in the power grid drives the air compressor 100 to work, so that the air compressor 100 compresses the air and outputs 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, cool, and reduce pressure, forming 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] Exemplarily, the low-temperature air flow rate 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 cold capacity needs to be provided at this time to enable the air to liquefy. At this time, the first refrigeration compressor 600 can be operated to compress the first refrigerant, and the compressed first refrigerant can be throttled, cooled and depressurized 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 normal temperature and 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, it is also necessary to provide additional cold capacity so that the air can be liquefied. 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 depressurized by the first refrigeration throttling device 700 to form a low-temperature refrigerant. The low-temperature refrigerant is input from the output end of the first refrigeration throttling device 700 into the first refrigerant channel 200d of the cooler group 200. 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 set up near a clean energy power station to more efficiently complete the peak load regulation task, relieve the pressure on the use of power plant equipment, and cope with the volatility of renewable energy. In addition, by supplementing the cold source of the air liquefaction process, the stability of the system and the flexibility of the operating time 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 cold 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, the cooler group 200 includes a plurality of coolers, each of which includes a first sub-channel 211, a second sub-channel 212 and a third sub-channel 213. Among them, the first cooling channel 200a is formed by connecting the first sub-channels 211 of each cooler in series; the second cooling channel 200b is formed by connecting the second sub-channels 212 of each cooler in series; the third cooling channel 200c is formed by connecting the third sub-channels 213 of each cooler in series; and the first refrigerant channel 200d is provided in at least one cooler. In the description of this application, the meaning of "plurality" is two or more.

[0035] For example, in Figure 1 In the example of , the cooler group 200 includes three coolers, namely, a first cooler 210, a second cooler 220 and a third cooler 230. The first cooler 210, the second cooler 220 and the third cooler 230 each include a first sub-channel 211, a second sub-channel 212 and a third sub-channel 213. The first cooling channel 200a is formed by 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 connected in series. The second cooling channel 200b is formed by 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 connected in series. The third cooling channel 200c is formed by 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 connected 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 by connecting the first sub-channels 211 of each cooler in series, the second cooling channel 200b is formed by connecting the second sub-channels 212 of each cooler in series, and the third cooling channel 200c is formed by connecting the third sub-channels 213 of each cooler in series. 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, thereby making it easier to achieve air liquefaction.

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

[0038] In one embodiment, referring to Figure 1 The plurality of coolers may include a first cooler 210, a second cooler 220, and a third cooler 230, and the first refrigerant channel 200d is disposed 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, in combination Figure 1 The first cooler 210 is connected between the air compressor 100 and the second cooler 220 , the third cooler 230 is connected between the air throttling device 300 and the second cooler 220 ; the first refrigerant channel 200d is arranged in the first cooler 210 .

[0040] For example, in Figure 1In the example of , the cold storage medium is output from the output end of the cold storage medium cold tank 800, and flows 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 in sequence, and finally input into the cold storage medium hot tank 900. The low-temperature air is output from the gaseous output end of the gas-liquid separator 400, and flows 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 in sequence. When the first refrigeration compressor 600 is working, the first refrigeration compressor 600 can compress the first refrigerant, and the compressed first refrigerant can be throttled, cooled and depressurized 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 from the output end of the first refrigeration throttling device 700.

[0041] In the energy storage stage, the air compressor 100 compresses the air, and the compressed air flows 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 in sequence. The air flowing through the first subchannel 211 of the first cooler 210 can absorb 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 can absorb 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 can absorb 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 to throttle, cool and reduce pressure to form 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, and 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.

[0042] In one embodiment, Figure 1As shown, the first cooler 210 and the second cooler 220 both include a second refrigerant channel 214. The liquid air energy storage system 10 may also 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] Exemplarily, when the second refrigeration compressor 10e is working, the second refrigeration compressor 10e can compress the second refrigerant, and the compressed second refrigerant enters the second refrigerant channel 214 of the first cooler 210, and is cooled by the first cooler 210. Then the second refrigerant is throttled, cooled and depressurized by the second refrigeration throttling device 10f, and is input into the second refrigerant channel 214 of the second cooler 220 from the output end of the second refrigeration throttling device 10f, and releases cold energy to the second cooler 220, so that the air flowing through the first sub-channel 211 of the second cooler 220 can absorb the cold 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 of the second refrigeration compressor 10e.

[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 form a second refrigeration cycle together. The cooling capacity provided by the second refrigerant can be changed by changing the flow rate or working parameters of the second refrigerant in the second refrigeration cycle. Moreover, the second refrigeration cycle and the first refrigeration cycle are independently arranged. Compared with 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, so that a multi-stage refrigeration cycle can be realized, providing stepped cooling capacity for air liquefaction to meet the demand for 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 also 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 of , 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 working, the third refrigeration compressor 10g can compress the third refrigerant, and the compressed third refrigerant flows through the third refrigerant channel 215 of the first cooler 210 and the third refrigerant channel 215 of the second cooler 220 in sequence, thereby being cooled by the first cooler 210 and the second cooler 220. Then the third refrigerant is throttled, cooled and depressurized by the third refrigeration throttling device 10h, and is input into the third refrigerant channel 215 of the third cooler 230 from the output end of the third refrigeration throttling device 10h, and releases cold energy to the third cooler 230, so that the air in the first sub-channel 211 flowing through the third cooler 230 can absorb the cold 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 form a third refrigeration cycle together. The cold released by the third refrigerant in the third refrigeration cycle is high-grade cold energy. The cold released by the second refrigerant in the above-mentioned second refrigeration cycle is medium-grade cold energy, and the cold released by the first refrigerant in the first refrigeration cycle is low-grade cold energy. Compared with the cold provided by the second refrigerant in the second refrigeration cycle, the cold 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 changed by changing the flow rate or working parameters of the third refrigerant in the third refrigeration cycle. Moreover, the third refrigeration cycle and the first refrigeration cycle are independently arranged, and the cooling capacity provided by the third refrigerant in the third refrigeration cycle is greater than that provided by the first refrigerant in the first refrigeration cycle, thereby realizing a multi-stage (such as three-stage) refrigeration cycle, providing stepped cooling capacity for air liquefaction, so as to meet the demand for air liquefaction.

[0049] In one embodiment, in combination 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 end of the first heat storage channel 110i is connected to the output end of the first refrigeration compressor 600, and the output end of the first heat storage channel 110i is connected to the input end of the first refrigeration throttling device 700. The input end of the second heat storage channel 120i is used to connect to the output end of the heat storage medium cold tank 10j, and the output end of the second heat storage channel 120i is used to connect to the input end of the heat storage medium hot tank 10k.

[0050] Exemplarily, in the energy storage stage, the heat storage medium is output from the heat storage medium cold tank 10j, flows through the second heat storage channel 120i of the heat storage heat exchanger 10i, and is input into the heat storage medium hot tank 10k after heat exchange with the first refrigerant in the first heat storage channel 110i. The first refrigeration cycle also includes the first heat storage channel 110i of the heat storage heat exchanger 10i. When the first refrigeration compressor 600 is working, the first refrigeration compressor 600 can compress the first refrigerant, and the compressed first refrigerant is input into the first heat storage channel 110i of the heat storage heat exchanger 10i. The first refrigerant in the first heat storage channel 110i can exchange heat with the heat storage medium flowing through the second heat storage channel 120i, thereby transferring the compression heat to the heat 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, so that the heat of the heat storage medium can be used to generate electricity during the peak period of electricity demand.

[0053] In one embodiment, Figure 1As shown, the liquid air energy storage system 10 may also 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, in the energy release stage, the cold storage medium is output 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 heat storage medium is output from the heat storage medium hot 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 output from the liquid air storage tank 500, and flows 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 in sequence. The air flowing through the first cold storage channel 110m can transfer cold energy to the cold storage medium to reduce 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, so that it can effectively 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, and can effectively release energy during the expansion process.

[0057] The second aspect of the present application provides a liquid air energy storage method, which is based on the liquid air energy storage system of the first aspect of the present application. 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: enabling 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;

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

[0060] Step S203: compress the first refrigerant using the first refrigeration compressor, and throttle 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] Exemplarily, the first refrigeration compressor, the first refrigeration throttling device and the first refrigerant channel may form a first refrigeration cycle circuit. The cooling capacity provided by the first refrigerant may be changed by changing the first refrigerant flow rate or operating parameters in the first refrigeration cycle circuit.

[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, thereby solving 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 beneficial 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 be adopted in 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 the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0069] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features.

[0070] In this application, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or a communication; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0071] In the present application, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is 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 that the first feature is 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 to realize the different structures of the present application. In order to simplify the disclosure of the present application, the parts and settings of specific examples are described above. Of course, they are only examples, and the purpose is not to limit the present application. In addition, the present application can repeat reference numerals and / or reference letters in different examples, and this repetition is for the purpose of simplification and clarity, which itself does not indicate the relationship between the various embodiments and / or settings discussed.

[0073] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of various changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope 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, 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.

2. The liquid air energy storage system according to claim 1, characterized in that: 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; and the first refrigerant channel is arranged in at least one cooler.

3. The liquid air energy storage system according to claim 2, characterized in that: 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.

4. The liquid air energy storage system according to claim 3, characterized in that: 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 arranged in the first cooler.

5. The liquid air energy storage system according to claim 4, characterized in that: 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, wherein an input end of the second refrigeration compressor is connected to an output end of a second refrigerant passage of the second cooler, and an output end of the second refrigeration compressor is connected to an input end of the second refrigerant passage 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.

6. The liquid air energy storage system according to claim 4, characterized in that: 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, 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.

7. The liquid air energy storage system according to any one of claims 1 to 6, characterized in that: Also includes: The heat storage heat exchanger comprises 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.

8. The liquid air energy storage system according to claim 7, characterized in that: Also includes: A cold storage heat exchanger, comprising 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; A heating heat exchanger having 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 heat storage medium hot tank, and the output end of the second heat exchange channel is connected to the input end of the heat storage medium cold tank; An air expander is connected to the output end of the first heat exchange channel.

9. The liquid air energy storage system according to claim 8, characterized in that: Also includes: A booster pump is connected between the liquid air storage tank and the cold storage heat exchanger.

10. 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 9, 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 gas output end of the gas-liquid separator outputs low-temperature air to the second cooling channel of the cooler group; 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; Compressing air with 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, and forms liquid air; Using an air throttling device to throttle the liquid air output from the first cooling channel to form gas-liquid two-phase air; The 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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