Supercritical carbon dioxide heat storage system and control method

Abstract

The present application relates to the technical field of physical energy storage, and provides a supercritical carbon dioxide heat storage system and a control method, the supercritical carbon dioxide heat storage system comprising: a first heat storage tank, a first heat exchanger, a second heat storage tank and a second heat exchanger, the first heat storage tank being used for storing heat storage medium; a medium inlet of the first heat exchanger being connected with a first outlet of the first heat storage tank through a heat storage main path, a medium outlet of the first heat exchanger being connected with a first inlet of the first heat storage tank through a first heat storage branch path, and heat storage medium flowing into the first heat exchanger being endothermic; an inlet of the second heat storage tank being connected with the medium outlet of the first heat exchanger through a second heat storage branch path; a medium inlet of the second heat exchanger being connected with a second outlet of the first heat storage tank and an outlet of the second heat storage tank through a first heat release flow path, and a medium outlet of the second heat exchanger being connected with a second inlet of the first heat storage tank through a second heat release flow path, and heat storage medium flowing into the second heat exchanger being exothermic. The present application has the characteristics of simple structure and low production cost.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of physical energy storage, in particular to a supercritical carbon dioxide heat storage system and a control method. BACKGROUND

[0002] At present, the conventional carbon dioxide energy storage system usually adopts cold and hot fluid storage in separate tanks when storing cold and heat, and since the density of carbon dioxide in various states is relatively small, the tank space required when storing in separate cold storage tanks and heat storage tanks is larger, and the tank needs to be high-pressure resistant, which leads to a more complex system structure, higher investment cost in equipment materials and land area. SUMMARY

[0003] The present application provides a supercritical carbon dioxide heat storage system and a control method to solve the defects of complex structure, high cost and low heat storage efficiency of the traditional energy storage system in the related art, and can improve the heat storage performance, enhance the heat conduction efficiency, simplify the system structure, reduce the production cost and reduce the heat loss; at the same time, effectively utilize carbon dioxide to achieve the purpose of energy saving and emission reduction.

[0004] The present application provides a supercritical carbon dioxide heat storage system, comprising:

[0005] A first heat storage tank for storing heat storage medium;

[0006] A first heat exchanger, a medium inlet of the first heat exchanger is connected to a first outlet of the first heat storage tank through a heat storage main path, a medium outlet of the first heat exchanger is connected to a first inlet of the first heat storage tank through a first heat storage branch path, and the heat storage medium flowing into the first heat exchanger is adapted to absorb heat;

[0007] A second heat storage tank, an inlet of the second heat storage tank is connected to a medium outlet of the first heat exchanger through a second heat storage branch path;

[0008] A second heat exchanger, a medium inlet of the second heat exchanger is connected to a second outlet of the first heat storage tank and an outlet of the second heat storage tank through a first heat release flow path respectively, a medium outlet of the second heat exchanger is connected to a second inlet of the first heat storage tank through a second heat release flow path, and the heat storage medium flowing into the second heat exchanger is adapted to release heat.

[0009] According to the supercritical carbon dioxide heat storage system provided by the present application, the heat storage medium in the first heat storage tank is liquid carbon dioxide, and the heat storage medium after absorbing heat is supercritical carbon dioxide.

[0010] According to the supercritical carbon dioxide heat storage system provided by the present application, the heat storage main path and / or the first heat release flow path is provided with a pressurizing and conveying device.

[0011] The supercritical carbon dioxide heat storage system provided by the application comprises a pressurizing and conveying device.

[0012] The supercritical carbon dioxide heat storage system provided by the application comprises a first heat storage branch, a second heat storage branch, a first heat release flow path and a second heat release flow path.

[0013] The supercritical carbon dioxide heat storage system provided by the application comprises a first heat storage tank and a second heat storage tank.

[0014] The supercritical carbon dioxide heat storage system provided by the application comprises a first heat storage tank and a second heat storage tank.

[0015] The supercritical carbon dioxide heat storage system provided by the application comprises a first heat storage tank and a second heat storage tank.

[0016] The supercritical carbon dioxide heat storage system provided by the application comprises a first heat storage tank and a second heat storage tank.

[0017] The application further provides a control method of the supercritical carbon dioxide heat storage system.

[0018] The control method comprises the following steps:

[0019] The control method comprises the following steps:

[0020] The control method comprises the following steps:

[0021] The control method comprises the following steps:

[0022] The application provides a supercritical carbon dioxide heat storage system and a control method. BRIEF DESCRIPTION OF DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the application or the related art, the following will briefly introduce the drawings needed to be used in the embodiments or the related art description. Obviously, the drawings in the following description are some embodiments of the application, and other drawings can be obtained by those skilled in the art without any creative effort on the basis of these drawings.

[0024] Figure 1 is a structural schematic diagram of the supercritical carbon dioxide heat storage system provided by the application;

[0025] Figure 2 is a heat storage mode operation principle diagram of the supercritical carbon dioxide heat storage system provided by the application;

[0026] Figure 3 is a heat release mode operation principle diagram of the supercritical carbon dioxide heat storage system provided by the application;

[0027] Figure 4 is a flow schematic diagram of the control method of the supercritical carbon dioxide heat storage system provided by the application.

[0028] REFERENCE SIGNS

[0029] 1: first heat storage tank; 2: first heat exchanger; 3: second heat storage tank;

[0030] 4: second heat exchanger; 5: main regenerative branch;

[0031] 7: second regenerative branch; 8: first heat releasing flow path; 9: second heat releasing flow path;

[0032] 10: circulating pump; 11: first regulating valve; 12: second regulating valve;

[0033] 13: third regulating valve; 14: fourth regulating valve; 15: fifth regulating valve. DETAILED DESCRIPTION

[0034] To make the objects, technical solutions and advantages of the present application clearer, the technical solutions in the present application will be described clearly and completely below with reference to the drawings in the present application. Obviously, the described embodiments are some, but not all, of the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0035] In the description of the embodiments of the present application, it should be noted that the terms "first", "second" and the like are only used for the purpose of description and should not be understood as indicating or implying relative importance.

[0036] In the description of the embodiments of the present application, it should be noted that unless otherwise explicitly specified and limited, the terms "connected", "connected" should be understood broadly, for example, it can be fixedly connected, or detachably connected, or integrally connected; it can be mechanically connected, or electrically connected; it can be directly connected, or indirectly connected through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0037] In the description of the present application, the description of the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present application, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any appropriate manner in any one or more embodiments or examples. In addition, those of ordinary skill in the art can combine and combine the different embodiments or examples described in the present application and the features of the different embodiments or examples without contradiction.

[0038] The present application will be described below in combination with Figures 1-4 The present application describes a supercritical carbon dioxide regenerative system and control method.

[0039] According to the embodiments of the first aspect of the present application, with reference to Figures 1-3 The supercritical carbon dioxide heat storage system provided by the present application mainly comprises a first heat storage tank 1, a first heat exchanger 2, a second heat storage tank 3 and a second heat exchanger 4.

[0040] The first heat storage tank 1 is used for storing circulating heat storage medium, which is generally low-temperature heat storage medium.

[0041] The medium inlet of the first heat exchanger 2 is connected with the first outlet of the first heat storage tank 1 through a heat storage main path 5, the medium outlet of the first heat exchanger 2 is connected with the first inlet of the first heat storage tank 1 through a first heat storage branch path 6, and the heat storage medium flowing into the first heat exchanger 2 is adapted to absorb heat. Specifically, during heat storage, the low-temperature heat storage medium flowing out of the first heat storage tank 1 flows into the first heat exchanger 2, absorbs the heat of the hot fluid flowing through the first heat exchanger 2, and is converted into high-temperature heat storage medium with a higher temperature, so that part of the high-temperature heat storage medium after heat exchange can be sent back to the first heat storage tank 1 through the first heat storage branch path 6, thereby realizing the storage of cold and hot fluids in the same tank. Compared with the traditional separate-tank sensible heat storage, the structure of the whole system can be simplified, the floor area can be reduced, and the production cost can be reduced. The heat storage tank has the characteristics of high heat storage density, small equipment floor area and low cost.

[0042] The inlet of the second heat storage tank 3 is connected with the medium outlet of the first heat exchanger 2 through a second heat storage branch path 7, so that another part of the high-temperature heat storage medium after heat exchange can be sent to the second heat storage tank 3, and part of the high-temperature heat storage medium is combined and returned to the first heat storage tank 1, thereby realizing double heat storage and effectively improving the heat storage performance and efficiency.

[0043] The medium inlet of the second heat exchanger 4 is connected with the second outlet of the first heat storage tank 1 and the outlet of the second heat storage tank 3 through a first heat release flow path 8, that is, the first heat release flow path 8 is arranged between the medium inlet of the second heat exchanger 4 and the second outlet of the first heat storage tank 1, and the first heat release flow path 8 is also arranged between the medium inlet of the second heat exchanger 4 and the outlet of the second heat storage tank 3. The medium outlet of the second heat exchanger 4 is connected with the second inlet of the first heat storage tank 1 through a second heat release flow path 9, and the heat storage medium flowing into the second heat exchanger 4 is adapted to release heat. Specifically, during heat release, the heat storage medium after heat absorption in the first heat storage tank 1 and the second heat storage tank 3 flows into the second heat exchanger 4 through the first heat release flow path 8 to release heat, and the heat storage medium after heat release flows back to the first heat storage tank 1 through the second heat release flow path 9, thereby realizing double heat release, fully utilizing the heat energy of the heat storage medium, and the low-temperature heat storage medium after heat release flows back into the first heat storage tank 1, thereby also realizing the effect of storing cold and hot fluids in the same tank.

[0044] Therefore, the supercritical carbon dioxide heat storage system can realize the circulating flow of the double heat storage and double heat release of the heat storage medium, effectively improve the heat storage and heat release efficiency, and the first heat storage tank 1 stores the cold and hot fluids in the same tank, compared with the traditional separate tank sensible heat storage, can simplify the structure of the whole system, reduce the floor area, and reduce the production cost, and the heat storage tank has the characteristics of high heat storage density, small equipment floor area, low cost and the like.

[0045] According to an embodiment of the present application, the heat storage medium in the first heat storage tank 1 is low-temperature liquid carbon dioxide with a relatively low temperature, and the heat storage medium after absorbing heat through the first heat exchanger 2 is high-temperature supercritical carbon dioxide with a relatively high temperature.

[0046] For the heat storage medium, the mainstream low-temperature heat storage medium in the current heat storage system is still water, methanol, heat conducting oil and the like, and supercritical carbon dioxide is also suitable for heat storage due to its close liquid density, specific heat capacity and heat transfer efficiency and similar viscosity to gas, and has stable chemical properties and very small corrosion compared with liquid heat storage medium. Therefore, carbon dioxide is also a good choice for heat storage medium.

[0047] The embodiment of the present application combines carbon dioxide into the heat storage system, uses carbon dioxide and supercritical carbon dioxide as the heat storage medium in the heat storage and heat release process, can effectively improve the working interval of the whole heat storage system, enhance the heat transfer efficiency, increase the utilization way of carbon dioxide, and through the use of carbon dioxide, the purpose of energy saving and emission reduction can be achieved.

[0048] According to an embodiment of the present application, referring to Figures 1-3 As shown in the figure, the heat storage main path 5 and / or the first heat release flow path 8 is provided with a pressurized conveying device, and the pressurized conveying device can realize the pressurized conveying of the heat storage medium, so as to realize the circulating flow of the heat storage medium.

[0049] According to an embodiment of the present application, the pressurized conveying device can be a compressor, a circulating pump 10 or other pressurized conveying equipment, and can be designed according to actual needs, and the present application does not make special limitation.

[0050] According to an embodiment of the present application, referring to Figures 1-3 As shown in the figure, the heat storage main path 5, the first heat storage branch path 6, the second heat storage branch path 7, the first heat release flow path 8 and the second heat release flow path 9 are respectively provided with adjusting valves, and the opening and closing of the adjusting valves can realize the switching control of the heat storage mode and the heat release mode.

[0051] For the convenience of clearly describing the switching process of the operation mode of the application, the regulating valve in the heat storage main path 5 is described as the first regulating valve 11, the regulating valve in the first heat storage branch path 6 is described as the second regulating valve 12, the regulating valve in the second heat storage branch path 7 is described as the third regulating valve 13, the regulating valve in the first heat release flow path 8 is described as the fourth regulating valve 14, and the regulating valve in the second heat release flow path 9 is described as the fifth regulating valve 15.

[0052] The operation mode of the heat storage system of the application mainly includes a heat storage mode and a heat release mode, and the switching process generally includes:

[0053] As shown in the heat storage mode in Figure 2 , the first regulating valve 11, the second regulating valve 12, and the third regulating valve 13 are controlled to be opened, and the fourth regulating valve 14 and the fifth regulating valve 15 are controlled to be closed; the circulating pump 10 in the heat storage main path 5 is controlled to be opened, the low-temperature heat storage medium in the first heat storage tank 1 flows into the first heat exchanger 2 through the circulating pump 10, absorbs the heat of the flowing heat fluid in the first heat exchanger 2, and is converted into high-temperature heat storage medium with a higher temperature, part of the high-temperature heat storage medium flows into the second heat storage tank 3, and the other part of the high-temperature heat storage medium flows back to the first heat storage tank 1; the heat storage time is controlled until the heat storage medium after heat absorption is in the first heat storage tank 1 and the second heat storage tank 3, and the heat storage is completed.

[0054] As shown in the heat release mode in Figure 3 , the first regulating valve 11, the second regulating valve 12, and the third regulating valve 13 are controlled to be closed, and the fourth regulating valve 14 and the fifth regulating valve 15 are controlled to be opened; the circulating pump 10 in the first heat release flow path 8 is controlled to be opened, the high-temperature heat storage medium after heat absorption in the first heat storage tank 1 and the second heat storage tank 3 flows into the second heat exchanger 4 through the first heat release flow path 8 to release heat, heats the cold fluid flowing into the second heat exchanger 4, and the heat-released heat storage medium flows back to the first heat storage tank 1 through the second heat release flow path 9, and the heat release is completed.

[0055] Of course, flow meters can also be arranged in each flow path to measure the flow of the heat storage medium in the flow path in real time, so as to realize more accurate control of the heat storage amount and the heat release amount.

[0056] According to an embodiment of the application, the shell of the first heat storage tank 1 and the second heat storage tank 3 is made of metal material, and different thicknesses can be used according to the specific design requirements of the pressure bearing strength, and the specific limitation is not made.

[0057] According to an embodiment of the application, an insulation and heat insulation layer is arranged outside the shell of the first heat storage tank 1 and the second heat storage tank 3, so as to reduce the heat loss of heat storage dissipation heat, and significantly improve the heat storage performance.

[0058] For example, the insulation and heat insulation layer material can be glass wool, rock wool, aerogel felt, expanded perlite, and foamed cement, etc.

[0059] According to one embodiment of the present application, the first heat exchanger 2 is connected to the compressor inter-stage heat exchanger. Specifically, when the system of the present application is operated in the heat storage mode, the low-temperature liquid carbon dioxide in the first heat storage tank 1 flows into the first heat exchanger 2 through the circulating pump 10, and the high-temperature hot fluid compressed by the compressor inter-stage heat exchanger flows into the first heat exchanger 2, and the low-temperature liquid carbon dioxide storage medium is heat-exchanged with the high-temperature hot fluid of the compressor inter-stage heat exchanger in the first heat exchanger 2, and is converted into high-temperature supercritical carbon dioxide after absorbing the compression heat, so that the heat of the compressor inter-stage heat exchanger is effectively utilized.

[0060] According to one embodiment of the present application, the second heat exchanger 4 is connected to the expander. Specifically, when the system of the present application is operated in the heat release mode, the high-temperature supercritical carbon dioxide storage medium in the first heat storage tank 1 and the second heat storage tank 3 flows into the second heat exchanger 4, and the carbon dioxide cold fluid for the expander flows into the second heat exchanger 4, and the high-temperature supercritical carbon dioxide storage medium is heat-exchanged with the carbon dioxide cold fluid in the second heat exchanger 4, and the carbon dioxide cold fluid is heated to become high-temperature carbon dioxide hot fluid and is sent into the expander to do work, so that the generator is driven to generate electricity, and the heat of the storage medium is effectively utilized.

[0061] According to one embodiment of the present application, the first heat exchanger 2 and the second heat exchanger 4 can be plate heat exchangers, or can be shell-and-tube heat exchangers, or can be other types of heat exchangers, and the specific design can be made according to actual needs, and the present application does not make special limitations.

[0062] In addition, the size of the heat storage tank, the number of stages of the heat exchanger, and the number of stages of the circulating pump can be appropriately adjusted according to the size of the entire system.

[0063] The working principle of the supercritical carbon dioxide heat storage system provided by the present application will be described below in combination with a specific example, which generally includes:

[0064] The heat storage process: the low-temperature liquid carbon dioxide storage medium flows from the first heat storage tank 1 to the first heat exchanger 2 through the circulating pump 10, and is heat-exchanged with the hot fluid flowing into the first heat exchanger 2 from the compressor inter-stage heat exchanger, and is converted into high-temperature supercritical carbon dioxide storage medium after absorbing the compression heat, wherein most of the supercritical carbon dioxide storage medium flows into the second heat storage tank 3, and a small part of the supercritical carbon dioxide storage medium flows back to the first heat storage tank 1, until the originally liquid carbon dioxide in the first heat storage tank 1 is completely discharged, and the first heat storage tank 1 and the second heat storage tank 3 are both filled with supercritical carbon dioxide storage medium, and the heat storage is completed.

[0065] The heat releasing process: the high-temperature supercritical carbon dioxide heat storage medium in the first heat storage tank 1 and the second heat storage tank 3 flows into the second heat exchanger 4 through the circulating pump 10, and heats the carbon dioxide that needs to be sent into the expander, and the heat-released carbon dioxide heat storage medium flows into the first heat storage tank 1 through the second heat releasing flow path 9, and the heat releasing is completed.

[0066] The control method of the supercritical carbon dioxide heat storage system provided by the present application is described below. The control method of the supercritical carbon dioxide heat storage system described below can be correspondingly referred to the supercritical carbon dioxide heat storage system described above.

[0067] According to the embodiment of the second aspect of the present application, referring to Figure 4 The present application also provides a control method of the supercritical carbon dioxide heat storage system of the above-mentioned embodiment, mainly including:

[0068] S100, obtaining a heat storage instruction.

[0069] S200, in response to the heat storage instruction, controlling the heat storage medium in the first heat storage tank 1 to flow into the first heat exchanger 2 through the heat storage main path 5 to absorb heat, and a part of the heat-absorbed heat storage medium flows back to the first heat storage tank 1 through the first heat storage branch path 6, and the other part flows into the second heat storage tank 3 through the second heat storage branch path 7, until the heat storage medium in the first heat storage tank 1 and the second heat storage tank 3 is heat-absorbed.

[0070] Specifically, in response to the heat storage instruction, the first regulating valve 11 in the heat storage main path 5, the second regulating valve 12 in the first heat storage branch path 6, and the third regulating valve 13 in the second heat storage branch path 7 are opened, the fourth regulating valve 14 in the first heat releasing flow path 8 and the fifth regulating valve 15 in the second heat releasing flow path 9 are closed, and the circulating pump 10 in the heat storage main path 5 is opened, the low-temperature heat storage medium in the first heat storage tank 1 flows into the first heat exchanger 2 through the circulating pump 10, absorbs the heat of the flowing heat fluid in the first heat exchanger 2, and is converted into high-temperature heat storage medium with higher temperature, part of the high-temperature heat storage medium flows into the second heat storage tank 3, and the other part of the high-temperature heat storage medium flows back to the first heat storage tank 1, by controlling the heat storage time, the heat storage medium in the first heat storage tank 1 and the second heat storage tank 3 is heat-absorbed, so that the heat storage is completed.

[0071] S300, obtaining a heat releasing instruction.

[0072] S400, in response to the heat releasing instruction, controlling the heat-absorbed heat storage medium in the first heat storage tank 1 and the second heat storage tank 3 to flow into the second heat exchanger 4 through the first heat releasing flow path 8 to release heat, and the heat-released heat storage medium flows back to the first heat storage tank 1 through the second heat releasing flow path 9.

[0073] Specifically, in response to the heat release instruction, the first regulating valve 11 in the heat storage main circuit 5, the second regulating valve 12 in the first heat storage branch circuit 6 and the third regulating valve 13 in the second heat storage branch circuit 7 are controlled to be closed, the fourth regulating valve 14 in the first heat release flow path 8 and the fifth regulating valve 15 in the second heat release flow path 9 are controlled to be opened, and the circulating pump 10 in the first heat release flow path 8 is controlled to be opened, the high-temperature heat storage medium in the first heat storage tank 1 and the second heat storage tank 3 after heat absorption flows into the second heat exchanger 4 through the first heat release flow path 8 to release heat, the cold fluid flowing into the second heat exchanger 4 is heated, and the heat-released heat storage medium flows back to the first heat storage tank 1 through the second heat release flow path 9, so as to complete the heat release.

[0074] The control method of the supercritical carbon dioxide heat storage system provided by the embodiment of the present application can return part of the high-temperature heat storage medium after heat exchange to the first heat storage tank 1 in response to the heat storage instruction, so as to realize the cold and hot fluid storage in the same tank. Compared with the traditional separate tank storage, the heat storage tank has the characteristics of high heat storage density, small equipment occupation area, low cost and the like, and another part of the high-temperature heat storage medium after heat exchange can be transported to the second heat storage tank 3, so as to realize double heat storage. In response to the heat release instruction, double heat release can be realized, the heat energy of the heat storage medium can be fully utilized, and the low-temperature heat storage medium after heat release flows back to the first heat storage tank 1, so as to also realize the effect of cold and hot fluid storage in the same tank. Therefore, the present application can simplify the structure of the entire heat storage system, so as to reduce the occupation area and production cost, and improve the heat storage and heat release performance and efficiency.

[0075] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, but not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A supercritical carbon dioxide thermal storage system, characterized in that, include: The first heat storage tank (1) is used to store the heat storage medium; The first heat exchanger (2) has its medium inlet connected to the first outlet of the first heat storage tank (1) via the main heat storage road (5), and its medium outlet connected to the first inlet of the first heat storage tank (1) via the first heat storage branch road (6). The heat storage medium flowing into the first heat exchanger (2) is suitable for heat absorption. The inlet of the second heat storage tank (3) is connected to the medium outlet of the first heat exchanger (2) via the second heat storage branch (7); The second heat exchanger (4) has its medium inlet connected to the second outlet of the first heat storage tank (1) and the outlet of the second heat storage tank (3) via the first heat release flow path (8), and its medium outlet connected to the second inlet of the first heat storage tank (1) via the second heat release flow path (9). The heat storage medium flowing into the second heat exchanger (4) is suitable for heat release. The heat storage medium in the first heat storage tank (1) is liquid carbon dioxide, and the heat storage medium after heat absorption is supercritical carbon dioxide. The main heat storage circuit (5), the first heat storage branch circuit (6), the second heat storage branch circuit (7), the first heat release flow circuit (8), and the second heat release flow circuit (9) are each equipped with a regulating valve. By controlling the opening and closing of the regulating valve, the switching control between the heat storage mode and the heat release mode can be realized.

2. The supercritical carbon dioxide thermal storage system according to claim 1, characterized in that, The heat storage main road (5) and / or the first heat release flow road (8) are equipped with a pressurization and conveying device.

3. The supercritical carbon dioxide thermal storage system according to claim 2, characterized in that, The booster pump is a compressor or a circulating pump (10).

4. The supercritical carbon dioxide thermal storage system according to any one of claims 1-3, characterized in that, The shells of the first heat storage tank (1) and the second heat storage tank (3) are provided with heat insulation layers.

5. The supercritical carbon dioxide thermal storage system according to any one of claims 1-3, characterized in that, The first heat exchanger (2) is connected to the compressor stage heat exchanger.

6. The supercritical carbon dioxide thermal storage system according to any one of claims 1-3, characterized in that, The second heat exchanger (4) is connected to the expander.

7. The supercritical carbon dioxide thermal storage system according to any one of claims 1-3, characterized in that, The first heat exchanger (2) and the second heat exchanger (4) are plate heat exchangers or shell-and-tube heat exchangers.

8. A control method for a supercritical carbon dioxide thermal storage system according to any one of claims 1-7, characterized in that, include: Obtain heat storage command; In response to the heat storage command, the heat storage medium in the first heat storage tank (1) is controlled to flow into the first heat exchanger (2) through the heat storage main road (5) to absorb heat. After absorbing heat, part of the heat storage medium flows back to the first heat storage tank (1) through the first heat storage branch road (6), and the other part flows into the second heat storage tank (3) through the second heat storage branch road (7) until the heat storage medium in both the first heat storage tank (1) and the second heat storage tank (3) is the heat storage medium after absorbing heat. Obtain heat release command; In response to the heat release command, the heat storage medium that has absorbed heat in the first heat storage tank (1) and the second heat storage tank (3) is controlled to flow into the second heat exchanger (4) through the first heat release flow path (8) to release heat, and the heat storage medium that has released heat flows back to the first heat storage tank (1) through the second heat release flow path (9).

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