A compact staged compressed air energy storage system

Abstract

This invention provides a compact staged compressed air energy storage system, comprising a compressor unit, an expander unit, an air storage device, a heat exchanger unit, and a thermocline tank. The compressor unit includes at least two coaxially connected compressor stages; the expander unit includes at least two expanders, each corresponding to one of the compressor stages; the heat exchanger unit includes at least two heat exchangers, each corresponding to one of the compressor stages. The first air-side port of each heat exchanger is connected to the outlet of the preceding compressor stage in an adjacent two-stage compressor, the second air-side port of each heat exchanger is connected to the inlet of the following compressor stage, and the second air-side port of the last heat exchanger stage is connected to the inlet of the air storage device. The system shares a single heat exchanger unit for both energy storage and release. Furthermore, through pipeline connections, the system allows for the simultaneous storage of both low-temperature and high-temperature heat transfer media within a single thermocline tank, thereby reducing the number of devices, simplifying the energy storage system structure, and lowering system costs and floor space requirements.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of compressed air energy storage, in particular to a compact staged compressed air energy storage system. BACKGROUND

[0002] The compressed air energy storage system is a new type of large-scale energy storage technology, and its working principle is similar to that of pumped storage. When the power consumption of the power system is in the valley, the air compressor is driven to consume electric energy, and the energy is stored in the form of compressed air in the air storage device. When the power consumption load of the power system reaches the peak, the air storage device releases the stored compressed air, which is expanded in the turbine expander to drive the generator to generate electricity.

[0003] Some compressed air energy storage systems in the prior art adopt a staged compression mode to prevent the increase of power consumption and low system efficiency caused by large pressure ratio quasi-isentropic compression. The compressed air energy storage system includes a plurality of coaxially connected compressors and a plurality of coaxially connected expanders. The compressor unit and the expander unit are separated, and the compressor unit and the expander unit are respectively connected to a set of heat storage and exchange system. The system uses a low-temperature storage tank and a high-temperature storage tank to store low-temperature heat transfer fluid and high-temperature heat transfer fluid, respectively, resulting in an increase in the number of devices used by the compressed air energy storage system, a complex structure, high cost, and a large occupied space. SUMMARY

[0004] Therefore, the technical problem to be solved by the present application is to overcome the defects of the compressed air energy storage system in the prior art, such as multiple devices, complex structure, high cost, and large occupied space.

[0005] To this end, the present application provides a compact staged compressed air energy storage system, comprising

[0006] The compressor unit comprises at least two levels of coaxially connected compressors;

[0007] The expander unit comprises at least two levels of expanders corresponding to the compressors one by one;

[0008] The air storage device;

[0009] The heat exchanger unit comprises at least two levels of heat exchangers corresponding to the compressors, the first gas side port of the heat exchanger is connected to the gas outlet of the front stage compressor among the adjacent two levels of compressors, the second gas side port of the heat exchanger is connected to the gas inlet of the rear stage compressor, the second gas side port of the last stage heat exchanger is connected to the gas inlet of the gas storage device, the gas outlet of the gas storage device is connected to the second gas side port of the last stage heat exchanger, the first gas side port of the last stage heat exchanger is connected to the gas inlet of the first stage expander, and the first gas side port of the rest of the heat exchangers is connected to the gas outlet of the front stage expander among the adjacent two levels of expanders, and the second gas side port of the rest of the heat exchangers is connected to the gas inlet of the rear stage expander.

[0010] The thermocline tank, the first medium port of each of the heat exchangers is connected to the first inlet and outlet of the thermocline tank through a first pipeline, and the second medium port of each of the heat exchangers is connected to the second inlet and outlet of the thermocline tank through a second pipeline, and a first circulating pump is arranged on the first pipeline, and a second circulating pump is arranged on the second pipeline.

[0011] Optionally, the compact multi-stage compressed air energy storage system described above, the first pipeline comprises a first main pipe and a first branch pipe, and the second pipeline comprises a second main pipe and a second branch pipe.

[0012] The first main pipe is connected to the first inlet and outlet of the thermocline tank, the first branch pipe is arranged corresponding to the heat exchanger and is communicated with the first main pipe, and the first circulating pump is arranged on the first main pipe.

[0013] The second main pipe is connected to the second inlet and outlet of the thermocline tank, the second branch pipe is arranged corresponding to the heat exchanger and is communicated with the second main pipe, and the second circulating pump is arranged on the second main pipe.

[0014] Optionally, the compact multi-stage compressed air energy storage system described above, a valve is arranged on each connecting pipeline between the compressor and the heat exchanger, on each connecting pipeline between the expander and the heat exchanger, on the first main pipe and on the second main pipe.

[0015] Optionally, the compact multi-stage compressed air energy storage system described above, the expander unit is coaxially connected with the compressor unit.

[0016] Optionally, the compact multi-stage compressed air energy storage system described above further comprises a photo-thermal heat collecting device, a first port of the photo-thermal heat collecting device is connected to the first medium port of all the heat exchangers in parallel through a third pipeline, and a second port of the photo-thermal heat collecting device is connected to the second medium port of all the heat exchangers in parallel through a fourth pipeline.

[0017] Optionally, the compact staged compressed air energy storage system described above, the third pipeline is connected in parallel with the first pipeline, the fourth pipeline is connected in parallel with the second pipeline, and a valve is arranged on the third pipeline.

[0018] Optionally, the compact staged compressed air energy storage system described above, the first port of the light-heat heat collecting device is connected to the second inlet and outlet of the thermocline storage tank through a fifth pipeline, and a valve is arranged on the fifth pipeline.

[0019] Optionally, the compact staged compressed air energy storage system described above, the third pipeline is connected in series with the fifth pipeline.

[0020] Optionally, the compact staged compressed air energy storage system described above further comprises a gas storage pipeline, two ends of the gas storage pipeline are respectively connected to a connecting pipeline between the last stage compressor and the heat exchanger and an air inlet of the gas storage device, and a valve is arranged on the gas storage pipeline.

[0021] Optionally, the compact staged compressed air energy storage system described above, the input shaft of the compressor unit is connected to a motor generator; and / or

[0022] The gas storage device is one or a combination of a gas storage tank, a pipeline steel beam gas storage library, an underground salt cave, a man-made underground chamber, a tunnel, and an underwater flexible air bag.

[0023] The technical scheme of the present application has the following advantages:

[0024] 1. The compact staged compressed air energy storage system provided by the present application shares a set of heat exchanger units for energy storage and energy release processes; and the system is connected by pipelines, so that the energy storage system stores low-temperature heat transfer medium and high-temperature heat transfer medium in a thermocline storage tank at the same time, thereby reducing the number of equipment, simplifying the structure of the energy storage system, reducing the cost and land occupation of the system.

[0025] The connection of the system by the pipelines makes the air flow from the first stage heat exchanger to the last stage heat exchanger in the energy storage compression process, the pressure through the first stage heat exchanger is the smallest, and the pressure through the last stage compressor is the largest; in the energy release expansion process, the air in the gas storage device flows from the last stage heat exchanger to the first stage heat exchanger, the pressure through the last stage heat exchanger is the largest, and the pressure through the first stage heat exchanger is the smallest, so that the design pressures of the heat exchangers can gradually increase from the first stage to the last stage, thereby reducing the manufacturing cost of the heat exchangers and improving the safety under the premise of ensuring the compactness of the energy storage system.

[0026] 2. The energy storage process, the photo-thermal collector converts light energy into heat energy storage; the energy release process, the heat transfer medium enters the heat exchanger through the second port, the fourth pipeline and the second medium port of the photo-thermal collector to further heat the high-pressure air, and the high-temperature photo-thermal is used to further increase the air temperature entering the expander, so that the compressor compression process can adopt a quasi-adiabatic compression process with a smaller pressure ratio, thereby reducing the power consumption of the compressor and improving the system efficiency. BRIEF DESCRIPTION OF DRAWINGS

[0027] In order to more clearly illustrate the technical solutions in the specific embodiments or prior art of the present application, the drawings needed in the specific embodiments or prior art description will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present application, and all other embodiments obtained by those skilled in the art without creative labor based on these drawings also belong to the protection scope of the present application.

[0028] Figure 1 The schematic diagram of the compact staged compressed air energy storage system provided by the embodiments of the present application.

[0029] Explanation of reference signs:

[0030] 101, primary compressor; 102, secondary compressor; 201, primary expander; 202, secondary expander; 30, air storage device; 401, primary heat exchanger; 402, secondary heat exchanger; 41, first air side port; 42, second air side port; 43, first medium port; 44, second medium port; 50, thermocline storage tank; 501, first inlet and outlet; 502, second inlet and outlet; 60, first circulating pump; 70, second circulating pump; 801, first main pipe; 802, first branch pipe; 901, second main pipe; 902, second branch pipe; 100, photo-thermal collector; 110, third pipeline; 120, fourth pipeline; 130, fifth pipeline; 140, air storage pipeline; 150, motor generator; 161, first valve; 162, second valve; 163, third valve; 164, fourth valve; 165, fifth valve; 166, sixth valve; 167, seventh valve; 168, eighth valve; 169, ninth valve; 1610, tenth valve; 1611, eleventh valve; 1612, twelfth valve; 1613, thirteenth valve; 1614, fourteenth valve. DETAILED DESCRIPTION

[0031] The technical solutions of the present application will be described below in conjunction with the drawings. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor also belong to the protection scope of the present application.

[0032] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0033] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0034] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0035] Example

[0036] This embodiment provides a compact staged compressed air energy storage system, such as Figure 1 As shown, it includes a compressor unit, an expander unit, a gas storage device 30, a heat exchanger unit, and a thermocline storage tank 50. The compressor unit includes at least two coaxially connected compressor stages; the expander unit includes at least two expander stages corresponding to the compressors; the heat exchanger unit includes at least two heat exchangers corresponding to the compressors, with the first gas-side port 41 of the heat exchanger connected to the outlet of the preceding compressor in an adjacent two-stage compressor, the second gas-side port 42 of the heat exchanger connected to the inlet of the following compressor, and the second gas-side port 42 of the last stage heat exchanger connected to the inlet of the gas storage device 30; the gas storage device 30 has an outlet... The second gas port 42 of the last stage heat exchanger is connected, the first gas port 41 of the last stage heat exchanger is connected to the inlet of the first stage expander, the first gas port 41 of the remaining heat exchangers is connected to the outlet of the previous stage expander in the two adjacent stages, and the second gas port 42 of the remaining heat exchangers is connected to the inlet of the next stage expander; the first medium port 43 of each heat exchanger is connected to the first inlet / outlet 501 of the inclined thermosphere storage tank 50 through the first pipeline, and the second medium port 44 of each heat exchanger is connected to the second inlet / outlet 502 of the inclined thermosphere storage tank 50 through the second pipeline. A first circulation pump 60 is provided on the first pipeline, and a second circulation pump 70 is provided on the second pipeline.

[0037] The compact staged compressed air energy storage system of this structure, during energy storage, the primary compressor 101 works, the compressed air is first compressed into high-temperature medium-pressure gas by the primary compressor 101, the high-temperature medium-pressure gas enters the primary heat exchanger 401 through the first gas side port 41, is cooled by heat exchange, and then enters the secondary compressor 102 through the second gas side port 42 to be pressurized and heated, and then enters the next stage heat exchanger to be cooled by heat exchange, and the compressed gas is cooled by heat exchange through the last stage heat exchanger and then enters the gas storage device 30 to be stored. During the energy storage process, under the action of the first circulating pump 60, the low-temperature heat transfer medium in the lower part of the temperature gradient storage tank 50 flows into all heat exchangers through the first inlet, the first pipeline and the first medium port 43, and the low-temperature heat transfer medium becomes high-temperature heat transfer medium after heat exchange with the high-temperature gas in the heat exchanger, the high-temperature heat transfer medium flows into the upper part of the temperature gradient storage tank 50 through the second medium port 44, the second pipeline and the second inlet and outlet 502, to store the heat energy of the compressed air, and the temperature gradient in the temperature gradient storage tank 50 moves downward.

[0038] During energy release, the low-temperature high-pressure air in the gas storage device 30 first flows into the last stage heat exchanger through the second gas side port 42 to be heated and become high-temperature high-pressure air, the high-temperature high-pressure air enters the primary expander 201 to be expanded and do work through the first gas side port 41, the low-temperature low-pressure air flowing out of the primary expander 201 enters the next stage heat exchanger to be heated and become high-temperature high-pressure air, and the high-temperature high-pressure air enters the next stage expander to be expanded and do work, until the compressed air is heated by the primary heat exchanger 401 and then enters the last stage expander to be expanded and do work to generate electricity. During the energy release process, under the action of the second circulating pump 70, the high-temperature heat transfer medium in the upper part of the temperature gradient storage tank 50 flows into all heat exchangers through the second inlet and outlet 502, the second pipeline and the second medium port 44, the low-temperature heat transfer medium after heat exchange between the high-temperature heat transfer medium and the low-temperature air in the heat exchanger flows into the bottom of the temperature gradient storage tank 50 through the first medium port 43, the first pipeline and the first inlet and outlet 501, and the temperature gradient moves upward.

[0039] The energy storage and energy release processes of the energy storage system share a set of heat exchanger units; and the system is connected through pipelines, so that the energy storage system stores the low-temperature heat transfer medium and the high-temperature heat transfer medium through one temperature gradient storage tank 50, to reduce the number of equipment, simplify the structure of the energy storage system, reduce the cost and land space of the system.

[0040] In the air compression process, the air pressure is different after being compressed by different stages of compressor, and the design pressure of different stages of heat exchanger is also different. With the increase of the stage number, the higher the air pressure, the higher the pressure resistance required by the heat exchanger material, and the higher the manufacturing cost of the heat exchanger. In the expansion process, with the increase of the stage number, the pressure through the heat exchanger is lower and lower. In order to make each heat exchanger be used efficiently in the process of heat storage and energy release, the system connects the pipes to make the air flow from the first heat exchanger 401 to the last heat exchanger in the energy storage compression process, and the pressure through the first heat exchanger 401 is the smallest and the pressure through the last compressor is the largest. In the energy release expansion process, the air in the air storage device 30 flows from the last heat exchanger to the first heat exchanger 401, and the pressure through the last heat exchanger is the largest and the pressure through the first heat exchanger 401 is the smallest, so that the design pressure of each heat exchanger can gradually increase from the first stage to the last stage, and the manufacturing cost of the heat exchanger is reduced and the safety is improved under the premise of ensuring the compactness of the energy storage system structure.

[0041] The thermocline storage tank is a pressure vessel, and the inside of the thermocline storage tank can be filled with gravel and other heat storage materials to store part of the heat, or only store heat transfer medium inside the thermocline storage tank. The heat storage material can be sensible heat material, phase change material or a combination of the two.

[0042] Referring to Figure 1 , the first pipe includes a first main pipe 801 and a first branch pipe 802, and the second pipe includes a second main pipe 901 and a second branch pipe 902; the first main pipe 801 is connected to the first inlet and outlet 501 of the thermocline storage tank 50, the first branch pipe 802 is provided in one-to-one correspondence with the heat exchanger and is connected to the first main pipe 801, the two ends of the first branch pipe 802 are connected to the first main pipe 801 and the first medium port 43 respectively, and the first circulating pump 60 is arranged on the first main pipe 801; the second main pipe 901 is connected to the second inlet and outlet 502 of the thermocline storage tank 50, the second branch pipe 902 is provided in one-to-one correspondence with the heat exchanger and is connected to the second main pipe, the two ends of the second branch pipe 902 are connected to the second main pipe and the second medium port 44 respectively, and the second circulating pump 70 is arranged on the second main pipe. By connecting the multiple first branch pipes 802 in parallel with the first main pipe 801 and the multiple second branch pipes 902 in parallel with the second main pipe, the system can connect all the heat exchangers and the thermocline storage tank 50 through one first main pipe 801 and one second main pipe, so as to simplify the system pipeline and facilitate to ensure the neatness of the energy storage system and reduce the system floor space.

[0043] Valves are arranged on each connection pipeline between the compressor and the heat exchanger, on each connection pipeline between the expander and the heat exchanger, and on the first main pipe 801 and the second main pipe, so as to facilitate to control the on-off of each pipeline as needed.

[0044] Referring to Figure 1 , the expander unit and the compressor unit are coaxially connected, the system structure is regular, and it is beneficial to the compactness of the energy storage system structure.

[0045] Referring to Figure 1 , the compact hierarchical compressed air energy storage system further comprises a photo-thermal heat collecting device 100, a first port of the photo-thermal heat collecting device 100 is connected to all the first medium ports 43 of the heat exchangers in parallel through a third pipeline 110, and a second port of the photo-thermal heat collecting device 100 is connected to all the second medium ports 44 of the heat exchangers in parallel through a fourth pipeline 120. In the energy storage process, the photo-thermal heat collecting device 100 converts light energy into heat energy for storage; in the energy release process, the heat transfer medium enters the heat exchangers through the second port of the photo-thermal heat collecting device 100, the fourth pipeline 120 and the second medium port 44 to further heat the high-pressure air, and the high-temperature photo-thermal heat is used to further increase the temperature of the air entering the expander, so that the compressor compression process can adopt a quasi-adiabatic compression process with a smaller pressure ratio, thereby reducing the power consumption of the compressor and improving the system efficiency. The heat transfer medium after heat exchange with the air flows back to the photo-thermal heat collecting device 100 through the first medium port 43, the first branch pipe 802, the first main pipe 801 and the third pipeline 110 and the first port.

[0046] For example, the photo-thermal heat collecting device 100 is a photo-thermal heat collector. In addition to the trough type heat collector, the photo-thermal heat collecting device 100 can also be any form of photo-thermal heat collector such as a tower type, a Fresnel type, a dish type, etc.

[0047] Referring to Figure 1 , a valve is arranged on the third pipeline 110, and by controlling the opening and closing of the valve on the first main pipe 801 and the third pipeline 110, it can be selected to heat the compressed air in the heat exchanger only by the high-temperature heat transfer medium in the upper part of the temperature-stratified tank 50 or the heat transfer medium in the photo-thermal heat collecting device 100, or to heat the compressed air in the heat exchanger by both the high-temperature heat transfer medium in the upper part of the temperature-stratified tank 50 and the heat transfer medium in the photo-thermal heat collecting device 100.

[0048] The first port of the photo-thermal heat collecting device 100 is connected to the second inlet and outlet 502 of the temperature-stratified tank 50 through a fifth pipeline 130, and a valve is arranged on the fifth pipeline 130 to form a circulating loop between the temperature-stratified tank 50 and the photo-thermal heat collector through the fifth pipeline 130, the first main pipe 801, the second main pipe and the fourth pipeline 120. When there is light, the low-temperature heat transfer medium in the lower part of the temperature-stratified tank 50 flows into the photo-thermal heat collector through the first main pipe 801, the second main pipe and the fourth pipeline 120 after being heated, and then flows to the upper part of the temperature-stratified tank 50 through the fifth pipeline 130 and the second main pipe, and circulates multiple times to increase the heat storage temperature of the temperature-stratified tank 50 and improve the heat storage energy density per unit volume.

[0049] Referring to Figure 1The third pipeline 110 is connected with the fifth pipeline 130 in series to connect the second header pipe and the third pipeline 110 through the fifth pipeline 130, so as to simplify the pipeline structure. The end of the third pipeline 110 away from the fifth pipeline 130 is connected with the first header pipe 801 in parallel to connect the first medium ports 43 of the heat exchangers through the first header pipe 801 and the first branch pipes 802. Similarly, the fourth pipeline 120 is connected with the second header pipe in parallel to connect the second medium ports 44 of the heat exchangers through the second header pipe and the second branch pipes 902. The light-heat collector 100 and the slope temperature layer storage tank 50 share the first header pipe 801, the second header pipe 901, the first branch pipes 802 and the second branch pipes 902 to complete the respective circulation processes, so that the pipeline arrangement is simple, the number of connection points and connecting pieces is reduced, and the system cost is reduced.

[0050] Optionally, the gas storage device 30 is one or a combination of a gas storage tank, a pipeline steel beam gas storage, an underground salt cave, an artificial underground chamber, a tunnel and an underwater flexible air bag. The gas storage device 30 can be any device with pressure-bearing and sealing properties.

[0051] Referring to Figure 1 The compact staged compressed air energy storage system further comprises a gas storage pipeline 140, two ends of the gas storage pipeline 140 are respectively connected with the connecting pipeline between the last stage compressor 101 and the heat exchanger and the gas inlet of the gas storage device 30, and a valve is arranged on the gas storage pipeline 140. When the gas storage device 30 is an underground chamber or an underground salt cave with heat preservation function, the valve on the gas storage pipeline 140 can be opened, and the air compressed by the last stage compressor 101 directly flows to the gas storage device 30 through the gas storage pipeline 140 for storage, so as to reduce the heat exchange loss of high-temperature air.

[0052] The input shaft of the compressor unit is connected with the motor generator 150, and the motor generator 150 drives the compressor to work during energy storage.

[0053] For example, the compressor unit is provided with a first stage compressor 101 and a second stage compressor 102, the expander unit is provided with a first stage expander 201 and a second stage expander 202, and the heat exchanger unit is provided with a first stage heat exchanger 401 and a second stage heat exchanger 402. The two compressors are coaxially connected with the two expanders. A motor generator 150 is arranged at the input shaft end of the first stage compressor 101, and the input shaft of the motor generator 150 is connected with the input shaft of the compressor. During energy storage, the motor generator 150 is used as a motor, the input shaft of the compressor and the output shaft of the motor generator 150 are kept synchronous rotation, and the output shaft of the expander is disconnected with the output shaft of the motor generator 150; during energy release, the input shaft of the compressor is disconnected with the output shaft of the motor generator 150, and the output shaft of the expander is connected with the output shaft of the motor generator 150 to keep synchronous rotation. The motor generator 150 can also be arranged between the compressor unit and the expander unit.

[0054] The connecting pipeline between the first stage compressor 101 and the first stage heat exchanger 401 is a first connecting pipeline, the connecting pipeline between the first stage heat exchanger 401 and the second stage compressor 102 is a second connecting pipeline, the connecting pipeline between the second stage compressor 102 and the second stage heat exchanger 402 is a third connecting pipeline, the pipeline into the first stage expander 201 is a fourth connecting pipeline, the pipeline into the second stage expander 202 is a fifth connecting pipeline, and the pipeline out of the first stage expander 201 is a sixth connecting pipeline. The end of the fourth connecting pipeline away from the first stage expander 201 is connected with the third connecting pipeline, the end of the fifth connecting pipeline away from the second stage expander 202 is connected with the second connecting pipeline, and the end of the sixth connecting pipeline away from the first stage expander 201 is connected with the first connecting pipeline, so that the first stage compressor 101 and the first stage heat exchanger 401, and the second stage expander 202 and the first stage heat exchanger 401 are connected through the first connecting pipeline, the second stage compressor 102 and the first stage heat exchanger 401, and the second stage expander 202 and the first stage heat exchanger 401 are connected through the second connecting pipeline, and the second stage compressor 102 and the second stage heat exchanger 402, and the first stage expander 201 and the second stage heat exchanger 402 are connected through the third pipeline, so that the heat exchangers are shared during the energy storage and release processes, and the system structure is simplified.

[0055] Referring to Figure 1, the first valve 161, the second valve 162, the third valve 163, the seventh valve 167 are opened, the motor generator 150 drives the primary compressor 101 to work, the compressed air is first compressed into high-temperature medium-pressure gas by the primary compressor 101, the high-temperature medium-pressure gas enters the primary heat exchanger 401 to be heat-exchanged and cooled, and then enters the secondary compressor 102 to be pressurized and heated, and then enters the secondary heat exchanger 402 to be heat-exchanged and cooled, and then enters the gas storage device 30 to be stored. At the same time, the eleventh valve 1611, the fourteenth valve 1614 and the thirteenth valve 1613 are opened, the low-temperature heat transfer medium in the lower part of the temperature-gradient layer storage tank 50 flows into the primary heat exchanger 401 and the secondary heat exchanger 402 through the first main pipe 801 and the two first branch pipes 802 respectively, the low-temperature heat transfer medium becomes high-temperature heat transfer medium after being heat-exchanged with the high-temperature gas in the heat exchanger, and the high-temperature heat transfer medium flows back to the upper part of the temperature-gradient layer storage tank 50 through the second branch pipe 902 and the second main pipe.

[0056] When the energy storage system stores energy, the first valve 161, the second valve 162, the third valve 163, and the seventh valve 167 are opened, the motor generator 150 drives the primary compressor 101 to work, the compressed air is first compressed into high-temperature medium-pressure gas by the primary compressor 101, the high-temperature medium-pressure gas enters the primary heat exchanger 401 to be heat-exchanged and cooled, and then enters the secondary compressor 102 to be pressurized and heated, and then enters the secondary heat exchanger 402 to be heat-exchanged and cooled, and then enters the gas storage device 30 to be stored. At the same time, the eleventh valve 1611, the fourteenth valve 1614 and the thirteenth valve 1613 are opened, the low-temperature heat transfer medium in the lower part of the temperature-gradient layer storage tank 50 flows into the primary heat exchanger 401 and the secondary heat exchanger 402 through the first main pipe 801 and the two first branch pipes 802 respectively, the low-temperature heat transfer medium becomes high-temperature heat transfer medium after being heat-exchanged with the high-temperature gas in the heat exchanger, and the high-temperature heat transfer medium flows back to the upper part of the temperature-gradient layer storage tank 50 through the second branch pipe 902 and the second main pipe.

[0057] When the energy is released, the low-temperature and high-pressure air in the gas storage device 30 first flows into the secondary heat exchanger 402 to be heated and become high-temperature and high-pressure air, which enters the primary expander 201 to expand and do work. The low-temperature and low-pressure air from the primary expander 201 enters the primary heat exchanger 401 to be heated and become high-temperature and high-pressure air, which enters the secondary expander 202 to expand and do work to drive the motor generator 150 to generate electricity. At the same time, the thirteenth valve 1613, the fourteenth valve 1614 and the eleventh valve 1611 are opened, the high-temperature heat transfer medium in the upper part of the temperature-gradient layer storage tank 50 flows into the two heat exchangers through the second main pipe and the two second branch pipes 902, respectively, the low-temperature heat transfer medium after heat exchange with the low-temperature air in the heat exchanger flows into the bottom of the temperature-gradient layer storage tank 50 through the first branch pipe 802 and the first main pipe 801; or the ninth valve 169 and the tenth valve 1610 are opened, the high-temperature heat transfer medium in the light-heat collector 100 flows into the heat exchanger through the fourth pipeline 120, the second main pipe and the second branch pipe 902, and the low-temperature heat transfer medium after heat exchange flows back to the light-heat collector 100 through the first branch pipe 802, the first main pipe 801, the third pipeline 110 and the fifth pipeline 130.

[0058] When the light is sufficient, the twelfth valve 1612 is opened, the low-temperature heat transfer medium in the lower part of the temperature-gradient layer storage tank 50 flows into the light-heat collector to be heated, and then flows to the upper part of the temperature-gradient layer storage tank 50 through the fifth pipeline 130 and the second main pipe, and circulates multiple times to heat the heat transfer medium in the temperature-gradient layer storage tank 50.

[0059] Obviously, the above-mentioned embodiments are only examples for clearly illustrating, but not limit the embodiments. For those skilled in the art, other different forms of changes or variations can be made on the basis of the above description. Here, all the embodiments need not and cannot be exhausted. The obvious changes or variations derived therefrom are still within the protection scope of the present application.

Claims

1. A compact, staged compressed air energy storage system, characterized by, Comprise: Compressor unit, comprising at least two levels of coaxial connection of compressor; Expander unit, comprising at least two levels of each corresponding to the setting of the expander; Gas storage device (30); Heat exchanger unit, comprising at least two levels of each corresponding to the setting of the heat exchanger, wherein the energy storage: the first gas side port (41) of each level heat exchanger is connected to the gas outlet of the former stage compressor in the adjacent two levels, and the second gas side port (42) is connected to the gas inlet of the latter stage compressor, the first gas side port (41) of the last heat exchanger is connected to the gas outlet of the last stage compressor, and the second gas side port (42) is connected to the gas inlet of the gas storage device (30); When releasing energy, the gas outlet of the gas storage device (30) is switched to connect the second gas side port (42) of the last heat exchanger, the first gas side port (41) of the last heat exchanger is switched to connect the gas inlet of the first stage expander, and the first gas side port (41) of the remaining each level heat exchanger is switched to connect the gas outlet of the former stage expander in the adjacent two levels, and the second gas side port (42) is switched to connect the gas inlet of the latter stage expander; The first medium port (43) of each heat exchanger is connected to the first inlet and outlet (501) of the thermocline tank (50) through the first pipeline, and the second medium port (44) is connected to the second inlet and outlet (502) of the thermocline tank (50) through the second pipeline, and the first circulating pump (60) is arranged on the first pipeline, and the second circulating pump (70) is arranged on the second pipeline; It also includes a photo-thermal heat collecting device (100), the first port of which is communicated with the first medium port (43) of each heat exchanger through the third pipeline (110) provided with a valve (1610), and the second port is communicated with the second medium port (44) of each heat exchanger through the fourth pipeline (120); And the end of the third pipeline (110) flows into the first pipeline, and the end of the fourth pipeline (120) flows into the second pipeline; It also includes a gas storage pipeline (140), which includes two branch pipelines connected to the exhaust pipeline of the last stage compressor, one of which is provided with a valve (168) and directly communicated to the gas inlet of the gas storage device (30), and the other is provided with a valve (167) and communicated to the gas inlet of the gas storage device (30) through the gas side of the last heat exchanger; The first pipeline comprises a first main pipe (801) and a first branch pipe (802), and the second pipeline comprises a second main pipe (901) and a second branch pipe (902), wherein; The first circulating pump (60) is arranged on the first main pipe (801), one end of which is connected to the first inlet and outlet (501) of the thermocline tank (50) and the end of the third pipeline (110), and the other end is connected to one end of each first branch pipe (802); The other end of each first branch pipe (802) is connected to the first medium port (43) of each heat exchanger one by one; One end of each second branch pipe (902) is connected to a second medium port (44) of each heat exchanger, and the other end is connected to one end of a second main pipe. The other end of the second main pipe is connected to a second inlet and outlet (502) of the thermocline storage tank (50) and the end of the fourth pipeline (120). A second circulating pump (70) is arranged on the pipe section between the second main pipe and the thermocline storage tank (50).

2. The compact, staged compression air energy storage system of claim 1, wherein, Valves are arranged on each connecting pipeline between the compressors and the heat exchangers, on each connecting pipeline between the expanders and the heat exchangers, on the first main pipe (801), and on the second main pipe.

3. The compact, cascaded compressed air energy storage system of claim 1 or 2, wherein, The expander unit is coaxially connected to the compressor unit.

4. The compact, staged compression air energy storage system of claim 1, wherein, The first port of the light-heat heat collection device (100) is also connected to the second inlet and outlet (502) of the thermocline storage tank (50) through a fifth pipeline (130). A valve is arranged on the fifth pipeline (130).

5. The compact, staged compression air energy storage system of claim 4, wherein, The third pipeline (110) and the fifth pipeline (130) are connected in series.

6. The compact, cascaded compressed air energy storage system of claim 1 or 2, wherein, The input shaft of the compressor unit is connected to a motor generator (150); and / or The gas storage device (30) is a combination of one or more of a gas storage tank, a pipeline steel beam gas storage, an underground salt cave, a man-made underground chamber, a tunnel, and an underwater flexible gas bag.

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