Carbon dioxide energy storage system, its unit cooling device and control method

Abstract

The present invention discloses a carbon dioxide energy storage system, its unit cooling device and control method. The unit cooling device includes a first cooling circulation loop and a second cooling circulation loop. The first cooling circulation loop includes a first pipeline, a cooling tower and a second pipeline that are sequentially connected between the unit equipment heat exchanger and the cooling circulation pump. The second cooling circulation loop includes a third pipeline, a second evaporator and a fourth pipeline that are sequentially connected between the unit equipment heat exchanger and the cooling circulation pump. The second evaporator is connected in parallel with the first evaporator in the energy storage system between the liquid storage unit and the energy release component. According to the operating conditions of the carbon dioxide energy storage system, the first cooling circulation loop or the second cooling circulation loop is selected to cool the system unit. The solution of the present invention not only reduces the consumption of plant electricity but also reduces the evaporation loss of circulating water, and can also recover and utilize the heat of the unit equipment, thereby reducing the operating cost of the system and improving the comprehensive efficiency of the system.

Description

Technical Field

[0001] The present invention relates to the technical field of carbon dioxide energy storage, and particularly to a carbon dioxide energy storage system, a unit cooling device thereof, and a control method. Background Art

[0002] At present, the energy storage technology based on the carbon dioxide gas-liquid phase change cycle stores the heat generated during the compression process by using surplus power during the low electricity consumption period or clean energy to compress and condense gaseous carbon dioxide at normal temperature and pressure in the gas storage unit into liquid carbon dioxide and store it in the liquid storage unit. During the high electricity consumption period, the stored heat energy is used to heat the liquid carbon dioxide to gas state, and the gaseous carbon dioxide drives the turbine to drive the generator to generate electricity. The gaseous carbon dioxide after doing work returns to the gas storage unit for recycling. It has the advantages of simple structure, flexible layout, and high energy storage efficiency, which has gradually attracted wide attention.

[0003] During the operation of the carbon dioxide energy storage system, a large amount of heat is generated by the unit equipment. For example, the bearings of rotating equipment such as compressors and turbines, and the coils of generators will generate a large amount of heat, and cooling and heat dissipation are required to maintain the normal operating temperature of the equipment. The existing unit cooling method usually sets up a cooling tower, and the circulating water in the cooling tower is introduced into the heat exchanger of the unit equipment for heat exchange to take away the heat generated by the unit equipment, so as to reduce the temperature of the equipment, thereby maintaining the performance and reliability of the equipment and preventing damage to the equipment caused by overheating.

[0004] In order to effectively control the temperature of the circulating water to ensure the normal operation of the unit, an additional cooling circulation fan is usually required to be set in the cooling tower to accelerate the heat dissipation process in the existing cooling scheme. And, since there will be a large evaporation loss when the circulating water cools down in the cooling tower, a water replenishing mechanism also needs to be set in the cooling tower to continuously supplement the low-temperature circulating water. On the one hand, both the cooling circulation fan and the water replenishing mechanism greatly increase the plant power consumption. On the other hand, the large evaporation loss of the circulating water in the cooling tower will increase the operating cost of the carbon dioxide energy storage system and reduce the overall efficiency of the entire system. Summary of the Invention

[0005] Aiming at the problems existing in the prior art, the present invention provides a carbon dioxide energy storage system, a unit cooling device thereof, and a control method, to solve the problem of how to reduce the operating cost of the carbon dioxide energy storage system and improve the overall efficiency of the system.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] The first aspect of the present invention is to provide a unit cooling device for a carbon dioxide energy storage system. The carbon dioxide energy storage system includes a first evaporator connected between a liquid storage unit and an energy release component. The unit cooling device includes a unit equipment heat exchanger, a first cooling circulation loop, and a second cooling circulation loop;

[0008] The cold side inlet of the unit equipment heat exchanger is connected to a cooling circulation pump. The first cooling circulation loop includes a first pipeline, a cooling tower, and a second pipeline sequentially connected between the cold side outlet of the unit equipment heat exchanger and the cooling circulation pump. The second cooling circulation loop includes a third pipeline, a second evaporator, and a fourth pipeline sequentially connected between the cold side outlet of the unit equipment heat exchanger and the cooling circulation pump. The second evaporator is connected in parallel with the first evaporator between the liquid storage unit and the energy release component;

[0009] Wherein, according to the operating conditions of the carbon dioxide energy storage system, the first cooling circulation loop or the second cooling circulation loop is selected to cool the system unit via the unit equipment heat exchanger.

[0010] In a specific solution, a first control valve is provided on the first pipeline, and a second control valve is provided on the third pipeline; wherein, according to the operating conditions of the carbon dioxide energy storage system, by controlling the opening and closing states of the first control valve and the second control valve, the first cooling circulation loop or the second cooling circulation loop is selected to cool the system unit via the unit equipment heat exchanger.

[0011] In a specific solution, the hot side inlet of the second evaporator is connected to the cold side outlet of the unit equipment heat exchanger through the third pipeline, and the hot side outlet of the second evaporator is connected to the cooling circulation pump through the fourth pipeline; the cold side inlet of the second evaporator is connected to the outlet of the liquid storage unit through a fifth pipeline, and the cold side outlet of the second evaporator is connected to the inlet of the energy release component through a sixth pipeline; wherein, a liquid inlet regulating valve is provided on the fifth pipeline for regulating the flow rate of the liquid carbon dioxide input from the liquid storage unit to the second evaporator; a temperature sensor is connected to the sixth pipeline for detecting the temperature of the gaseous carbon dioxide input from the second evaporator to the energy release component.

[0012] In a specific solution, a check valve is provided on the second pipeline.

[0013] In a specific solution, the cooling tower includes a cooling tower body, a cooling circulation fan connected to the cooling tower body, and a water replenishing mechanism.

[0014] The second aspect of the present invention is to provide a carbon dioxide energy storage system, which includes a gas storage unit, an energy storage component, a liquid storage unit, and an energy release component that are connected in a closed loop in sequence, and also includes the unit cooling device as described above.

[0015] In a specific solution, a booster pump is connected to the outlet of the liquid storage unit, and the second evaporator and the first evaporator are connected in parallel between the booster pump and the energy release component.

[0016] The second aspect of the present invention is to provide a control method for the carbon dioxide energy storage system as described above. The control method includes:

[0017] S100. When the carbon dioxide energy storage system is in the energy storage working condition, use the first cooling circulation loop to cool the system unit via the unit equipment heat exchanger;

[0018] S200. When the carbon dioxide energy storage system is in the energy release working condition, detect and determine whether the temperature of the circulating water after heat exchange via the unit equipment heat exchanger exceeds the critical temperature of carbon dioxide: If not, use the first cooling circulation loop to cool the system unit via the unit equipment heat exchanger; If so, use the second cooling circulation loop to cool the system unit via the unit equipment heat exchanger;

[0019] Wherein, in step S200: When using the first cooling circulation loop for cooling, the liquid storage unit inputs liquid carbon dioxide into the first evaporator, and after evaporating to form gaseous carbon dioxide via the first evaporator, it is input into the energy release component; When using the second cooling circulation loop for cooling, the liquid storage unit inputs liquid carbon dioxide into the first evaporator and the second evaporator respectively, and after evaporating to form gaseous carbon dioxide via the first evaporator and the second evaporator respectively, it is input into the energy release component.

[0020] In a specific solution, step S200 specifically includes:

[0021] S201. When the energy release working condition of the carbon dioxide energy storage system starts to operate, use the first cooling circulation loop to cool the system unit via the unit equipment heat exchanger;

[0022] S202. When the carbon dioxide energy storage system is in full-load operation in the energy release working condition and the temperature of the circulating water after heat exchange via the unit equipment heat exchanger exceeds the critical temperature of carbon dioxide, use the second cooling circulation loop to cool the system unit via the unit equipment heat exchanger;

[0023] S203. When the energy release condition of the carbon dioxide energy storage system starts to unload and is about to stop running, use the first cooling circulation loop to cool the system unit via the unit equipment heat exchanger.

[0024] In a specific solution, when using the second cooling circulation loop for cooling, control the flow of the liquid carbon dioxide input to the second evaporator and monitor the temperature of the gaseous carbon dioxide output from the second evaporator to ensure that the temperature of the gaseous carbon dioxide output from the second evaporator reaches above the critical temperature.

[0025] The carbon dioxide energy storage system, its unit cooling device and control method provided by the embodiments of the present invention. The unit cooling device is provided with a first cooling circulation loop and a second cooling circulation loop. The first cooling circulation loop cools and dissipates heat from the unit equipment by using the traditional cooling tower cooling method. The second cooling circulation loop includes a second evaporator connected between the liquid storage unit and the energy release component. During the energy release condition, the liquid carbon dioxide input to the second evaporator is used to cool and dissipate heat from the unit equipment. Among them, according to the operating condition of the carbon dioxide energy storage system, select to use the first cooling circulation loop or the second cooling circulation loop to cool the system unit via the unit equipment heat exchanger. When using the second cooling circulation loop for cooling, the cooling tower and its auxiliary equipment (such as the cooling circulation fan, water replenishing mechanism) in the first cooling circulation loop can all stop running. Thereby, not only the plant power consumption is reduced, but also the evaporation loss of the circulating water is reduced, greatly reducing the operating cost of the system. Further, the heat of the unit equipment can also be recycled into the carbon dioxide energy storage system, improving the comprehensive efficiency of the system. Description of the Drawings

[0026] Figure 1 is a schematic structural diagram of the carbon dioxide energy storage system and its unit cooling device in the embodiments of the present invention. Detailed Embodiments

[0027] To make the objectives, technical solutions and advantages of the present invention clearer, the following will describe in detail the specific embodiments of the present invention with reference to the drawings. Examples of these preferred embodiments are illustrated in the drawings. The embodiments of the present invention shown in the drawings and described according to the drawings are merely exemplary, and the present invention is not limited to these embodiments.

[0028] It should be noted that the same or similar reference numerals in the drawings of the embodiments of the present invention correspond to the same or similar components; in the description of the present invention, it should be understood that if there are terms such as "upper", "lower", "left", "right", etc. indicating the orientation or positional relationship, they are based on the orientation or positional relationship shown in the drawings. This is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, the terms describing the positional relationship in the drawings are only for illustrative purposes and cannot be construed as a limitation of this patent. For those of ordinary skill in the art, the specific meanings of the above terms can be understood according to specific circumstances.

[0029] Here, it should also be noted that in order to avoid obscuring the present invention due to unnecessary details, only the structures and / or processing steps closely related to the solution according to the present invention are shown in the drawings, while other details less related to the present invention are omitted.

[0030] Refer to Figure 1 , the embodiments of the present invention first provide a unit cooling device 5 and a carbon dioxide energy storage system 100 including the unit cooling device 5.

[0031] Specifically, as Figure 1 shown, the carbon dioxide energy storage system 100 mainly includes a gas storage unit 1, an energy storage component 2, a liquid storage unit 3, and an energy release component 4 that are connected in a closed loop in sequence. Among them, the gas storage unit 1 is used to store gaseous carbon dioxide at normal pressure, and the liquid storage unit 3 is used to store liquid carbon dioxide. The gaseous carbon dioxide flowing out of the gas storage unit 1 is converted into liquid carbon dioxide at a preset energy storage pressure through the energy storage component 2 and flows into the liquid storage unit 3, and energy storage is completed in this process. The liquid carbon dioxide output from the liquid storage unit 3 releases energy through the energy release component 4 and is converted into gaseous carbon dioxide at normal pressure and flows into the gas storage unit 1, and energy release and application are completed in this process. Usually, the energy storage component 2 compresses and liquefies gaseous carbon dioxide into liquid carbon dioxide and stores it in the liquid storage unit 3 during the low electricity consumption period or by using abandoned wind and solar power, and stores the energy as compression energy and heat energy; during the high electricity consumption period, the energy release component 4 gasifies and expands the liquid carbon dioxide to do work, releases the stored energy and converts it into electrical energy for use.

[0032] Among them, the specific component structures of the gas storage unit 1, the energy storage component 2, the liquid storage unit 3, and the energy release component 4 can be implemented with reference to the existing technology. The gas storage unit 1 is also called a gas storage bin, a gas storage reservoir, a gas storage component, etc. in the existing technology, and the liquid storage unit 3 is also called a liquid storage tank, a liquid storage container, an energy storage container, etc. in the existing technology. For example, the technical solutions disclosed in the existing patent documents CN119289275A, CN116221616A, CN117628836A, and CN116857027A.

[0033] As a specific example, in this embodiment, as Figure 1 shown, the energy storage component 2 mainly includes a compressor 21 and a condenser 22 connected between the gas storage unit 1 and the liquid storage unit 3. The gaseous carbon dioxide in the gas storage unit 1 is compressed by the compressor 21 and then liquefied by the condenser 22 to form liquid carbon dioxide, which is stored in the liquid storage unit 3.

[0034] As a specific example, in this embodiment, as Figure 1 shown, the energy release component 4 mainly includes a superheater 41 and a turbine 42 connected between the liquid storage unit 3 and the gas storage unit 1. A first evaporator 6 is provided between the liquid storage unit 3 and the energy release component 4. The liquid carbon dioxide in the liquid storage unit 3 is pressurized by a booster pump 7 and then input into the first evaporator 6. After being heated and evaporated by the first evaporator 6, it is input into the superheater 41 for further heating to increase the temperature, and then input into the turbine 42 to do work externally (such as generating electricity) to release energy, and is converted into gaseous carbon dioxide at normal pressure and stored in the gas storage unit 1.

[0035] Among them, during the operation of the carbon dioxide energy storage system 100, a large amount of heat will be generated by the unit equipment therein. For example, the bearings of rotating equipment such as the compressor 21 and the turbine 42, and the coils of the generator will all generate a large amount of heat, and cooling and heat dissipation are required to maintain the normal operating temperature of the equipment. How to dissipate heat from the unit equipment to maintain the performance and reliability of the equipment and prevent damage to the equipment caused by overheating is a problem to be solved. For this reason, an embodiment of the present invention provides a unit cooling device 5, which is applied to the carbon dioxide energy storage system 100 as described above.

[0036] Specifically, as Figure 1 shown, the unit cooling device includes a unit equipment heat exchanger 51, a first cooling circulation loop 52, and a second cooling circulation loop 53.

[0037] Among them, the cold-side inlet of the unit equipment heat exchanger 51 is connected to a cooling circulation pump 54. The first cooling circulation loop 52 includes a first pipeline 521, a cooling tower 522, and a second pipeline 523 that are sequentially connected between the cold-side outlet of the unit equipment heat exchanger 51 and the cooling circulation pump 54. The second cooling circulation loop 53 includes a third pipeline 531, a second evaporator 532, and a fourth pipeline 533 that are sequentially connected between the cold-side outlet of the unit equipment heat exchanger 51 and the cooling circulation pump 54. The second evaporator 532 is connected in parallel with the first evaporator 6 between the liquid storage unit 3 and the energy release component 4.

[0038] Among them, according to the operating conditions of the carbon dioxide energy storage system 100, the first cooling circulation loop 52 or the second cooling circulation loop 53 is selected to cool the system unit via the unit equipment heat exchanger 51. Specifically, when the first cooling circulation loop 52 is selected to cool the system unit, the low-temperature circulating water in the cooling tower 522 is input into the unit equipment heat exchanger 51 via the second pipeline 523 and the cooling circulation pump 54, and the heat generated by the unit equipment is taken away through heat exchange. After heat exchange, the circulating water with increased temperature is input into the cooling tower 522 via the first pipeline 521 for cooling. When the second cooling circulation loop 53 is selected to cool the system unit, the circulating water with increased temperature after heat exchange in the unit equipment heat exchanger 51 is input into the second evaporator 532 via the third pipeline 531, and exchanges heat with the liquid carbon dioxide input into the second evaporator 532. On the one hand, the circulating water is cooled, and on the other hand, the liquid carbon dioxide is heated and evaporated to form carbon dioxide gas, which is input into the energy release component 4. The cooled circulating water is input into the unit equipment heat exchanger 51 again via the fourth pipeline 533 and the cooling circulation pump 54, and circulates in this way to take away the heat generated by the unit equipment through heat exchange.

[0039] Specifically, in this embodiment, as Figure 1 shown, a first control valve 524 is provided on the first pipeline 521, and a second control valve 534 is provided on the third pipeline 531. Among them, according to the operating conditions of the carbon dioxide energy storage system 100, by controlling the opening and closing states of the first control valve 524 and the second control valve 534, the first cooling circulation loop 52 or the second cooling circulation loop 53 is selected to cool the system unit via the unit equipment heat exchanger 51.

[0040] Among them, the cooling tower 522 includes a cooling tower body 5221, a cooling circulation fan 5222 and a water replenishing mechanism 5223 connected to the cooling tower body 5221. Further, in the first cooling circulation loop 52, a check valve 525 is provided on the second pipeline 523. When switching to using the second cooling circulation loop 53 to cool the system unit, the check valve 525 can prevent the circulating water flowing in the second cooling circulation loop 53 from flowing into the cooling tower 522.

[0041] Specifically, in the second cooling cycle loop 53, referring to FIG. 1, the hot-side inlet of the second evaporator 532 is connected to the cold-side outlet of the unit equipment heat exchanger 51 through the third pipeline 531, and the hot-side outlet of the second evaporator 532 is connected to the cooling circulation pump 54 through the fourth pipeline 533. The cold-side inlet of the second evaporator 532 is connected to the booster pump 7 through the fifth pipeline 535, and is connected to the outlet of the liquid storage unit 3 through the booster pump 7. The cold-side outlet of the second evaporator 532 is connected to the inlet of the energy release component 4 through the sixth pipeline 536. That is, in this embodiment, the second evaporator 532 and the first evaporator 6 are connected in parallel between the booster pump 7 and the energy release component 4.

[0042] Further, a liquid inlet regulating valve 537 is provided on the fifth pipeline 535, and the liquid inlet regulating valve 537 is used to regulate the flow rate of the liquid carbon dioxide input from the liquid storage unit 3 to the second evaporator 532. A temperature sensor 538 is connected to the sixth pipeline 536, and the temperature sensor 538 is used to detect the temperature of the gaseous carbon dioxide input from the second evaporator 532 to the energy release component 4.

[0043] Based on the carbon dioxide energy storage system 100 and its corresponding unit cooling device 5 provided in the above embodiments, the embodiment of the present invention further provides a control method for the carbon dioxide energy storage system 100, and the control method includes the following steps:

[0044] S100. When the carbon dioxide energy storage system 100 is in the energy storage working condition, use the first cooling cycle loop 52 to cool the system unit through the unit equipment heat exchanger 51.

[0045] Specifically, in the energy storage working condition, the heat generated by the unit equipment is transferred to the unit equipment heat exchanger 51. The cooling circulation pump 54 is started, the first control valve 524 is opened and the second control valve 534 is closed. The low-temperature circulating water in the cooling tower 522 is input into the unit equipment heat exchanger 51 through the second pipeline 523 and the cooling circulation pump 54, and the heat generated by the unit equipment is taken away through heat exchange. The circulating water after heat exchange and temperature rise is input into the cooling tower 522 through the first pipeline 521 for cooling, and the cooled circulating water is input into the unit equipment heat exchanger 51 again, and so on.

[0046] Among them, when the cooling tower 522 cools down the circulating water, the cooling circulation fan 5222 is started so that the circulating water exchanges heat with air forcibly in the cooling tower body 5221. At this time, due to the evaporation loss of the circulating water, the water replenishing mechanism 5223 needs to be opened for continuous water replenishment.

[0047] S200. When the carbon dioxide energy storage system 100 is in the energy release mode, detect and determine whether the temperature of the circulating water after heat exchange through the unit equipment heat exchanger 51 exceeds the critical temperature of carbon dioxide. If not, use the first cooling circulation loop 52 to cool the system unit through the unit equipment heat exchanger 51. If so, use the second cooling circulation loop 53 to cool the system unit through the unit equipment heat exchanger 51.

[0048] Among them, in step S200: when using the first cooling circulation loop 52 for cooling, the liquid storage unit 3 inputs liquid carbon dioxide into the first evaporator 6. After evaporating to form gaseous carbon dioxide through the first evaporator 6, it is input into the energy release component 4. When using the second cooling circulation loop 53 for cooling, the liquid storage unit 3 inputs liquid carbon dioxide into the first evaporator 6 and the second evaporator 532 respectively. After evaporating to form gaseous carbon dioxide through the first evaporator 6 and the second evaporator 532 respectively, it is input into the energy release component 4.

[0049] In a specific solution, step S200 specifically includes the following sub-steps:

[0050] S201. When the energy release mode of the carbon dioxide energy storage system 100 starts to operate, use the first cooling circulation loop 52 to cool the system unit through the unit equipment heat exchanger 51. The specific cooling and heat dissipation process is the same as that in step S100 above.

[0051] Among them, the liquid carbon dioxide in the liquid storage unit 3 is boosted by the booster pump 7 and then input into the first evaporator 6. After heating and evaporating to form gaseous carbon dioxide through the first evaporator 6, it is input into the energy release component 4.

[0052] S202. When the carbon dioxide energy storage system 100 is in full-load operation in the energy release mode and the temperature of the circulating water after heat exchange through the unit equipment heat exchanger 51 exceeds the critical temperature of carbon dioxide (usually 31 °C), use the second cooling circulation loop 53 to cool the system unit through the unit equipment heat exchanger 51.

[0053] Specifically, as the power of the unit equipment increases, the generated heat continuously increases. At this time, the heat exchange capacity of the heat exchanger 51 of the unit equipment increases, the temperature rises, and the temperature of the circulating water also gradually rises. When the temperature of the circulating water after heat exchange by the heat exchanger 51 of the unit equipment exceeds the critical temperature of carbon dioxide, the second control valve 534 is opened and the liquid inlet regulating valve 537 is opened. Liquid carbon dioxide enters the second evaporator 532 and absorbs the heat carried by the circulating water in the second evaporator 532 and evaporates into carbon dioxide gas. At this time, the first control valve 524 is closed, and the cooling circulation fan 5222 and the water replenishing mechanism 5223 are controlled to stop operating. The circulating water cooled in the second evaporator 532 is input into the heat exchanger 51 of the unit equipment again through the fourth pipeline 533 and the cooling circulation pump 54, and so on in a cycle.

[0054] Among them, the flow rate of the liquid carbon dioxide input into the second evaporator 532 is adjusted by the liquid inlet regulating valve 537, and the temperature of the carbon dioxide gas output from the second evaporator 532 is detected by the temperature sensor 538 to ensure that the temperature at the outlet end of the second evaporator 532 reaches above the critical temperature of carbon dioxide, so that all the carbon dioxide output from the outlet end of the second evaporator 532 is in a gaseous state.

[0055] In step S202, the liquid carbon dioxide output from the liquid storage unit 3 is respectively input into the first evaporator 6 and the second evaporator 532. After being evaporated into gaseous carbon dioxide through the first evaporator 6 and the second evaporator 532 respectively, it is input into the energy release component 4.

[0056] S203. When the energy release condition of the carbon dioxide energy storage system 100 starts to unload and is ready to stop operating, the first cooling circulation loop 52 is used to cool the system unit through the heat exchanger 51 of the unit equipment. The liquid inlet regulating valve 537 is closed, and the liquid carbon dioxide stops entering the second evaporator 532. The second control valve 534 is closed and the first control valve 524 is opened to switch to using the first cooling circulation loop 52 to cool the system unit. At this time, the liquid carbon dioxide in the liquid storage unit 3 is heated and evaporated into gaseous carbon dioxide through the first evaporator 6 and then input into the energy release component 4 until the energy release condition stops operating.

[0057] As described in the above embodiments, the carbon dioxide energy storage system, its unit cooling device and control method, the unit cooling device 5 is provided with a first cooling circulation loop 52 and a second cooling circulation loop 53. The first cooling circulation loop 52 uses the traditional cooling tower cooling method to cool and dissipate heat from the unit equipment. The second cooling circulation loop 53 includes a second evaporator 532 connected between the liquid storage unit 3 and the energy release component 4. During the energy release condition, the liquid carbon dioxide input to the second evaporator 532 is used to cool and dissipate heat from the unit equipment. Among them, according to the operating conditions of the carbon dioxide energy storage system 100, the first cooling circulation loop 52 or the second cooling circulation loop 53 is selected to cool the system unit via the unit equipment heat exchanger 51. When the second cooling circulation loop 53 is used for cooling, the cooling tower and its auxiliary equipment (such as the cooling circulation fan, water replenishing mechanism) in the first cooling circulation loop 52 can all stop operating. Thereby, not only the consumption of plant electricity is reduced, but also the evaporation loss of the circulating water is reduced, greatly reducing the operating cost of the system. Further, the heat of the unit equipment can also be recycled to the carbon dioxide energy storage system, improving the overall efficiency of the system.

[0058] The above description is only the specific implementation manners of the present application. It should be noted that for those of ordinary skill in the art in this technical field, without departing from the principle of the present application, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present application.

Claims

1. A unit cooling device of a carbon dioxide energy storage system, the carbon dioxide energy storage system comprising a first evaporator connected between a liquid storage unit and an energy release component, characterized in that: The unit cooling device comprises a unit equipment heat exchanger and a first cooling circulation loop and a second cooling circulation loop; The cold side inlet of the unit equipment heat exchanger is connected to a cooling circulation pump, the first cooling circulation loop comprises a first pipeline, a cooling tower and a second pipeline connected in sequence between the cold side outlet of the unit equipment heat exchanger and the cooling circulation pump, the second cooling circulation loop comprises a third pipeline, a second evaporator and a fourth pipeline connected in sequence between the cold side outlet of the unit equipment heat exchanger and the cooling circulation pump, the second evaporator and the first evaporator are connected in parallel between the liquid storage unit and the energy release component; According to the operating conditions of the carbon dioxide energy storage system, the first cooling cycle loop or the second cooling cycle loop is selected to cool the system unit via the unit equipment heat exchanger.

2. The unit cooling device according to claim 1, characterized in that: A first control valve is provided on the first pipeline, and a second control valve is provided on the third pipeline; wherein, by controlling the opening and closing states of the first control valve and the second control valve, the first cooling circulation loop or the second cooling circulation loop is selected to cool the system unit via the unit equipment heat exchanger.

3. The unit cooling device according to claim 1 or 2, characterized in that: The heat measurement inlet of the second evaporator is connected to the cold side outlet of the unit equipment heat exchanger through the third pipe, and the heat measurement outlet of the second evaporator is connected to the cooling circulation pump through the fourth pipe; the cold measurement inlet of the second evaporator is connected to the outlet of the liquid storage unit through the fifth pipe, and the cold measurement outlet of the second evaporator is connected to the inlet of the energy release component through the sixth pipe; wherein, a liquid inlet regulating valve is provided on the fifth pipe for regulating the flow of liquid carbon dioxide input from the liquid storage unit to the second evaporator; a temperature sensor is connected to the sixth pipe for detecting the temperature of the gaseous carbon dioxide input from the second evaporator to the energy release component.

4. The unit cooling device according to claim 1 or 2, characterized in that: The second pipeline is provided with a check valve.

5. The unit cooling device according to claim 1, characterized in that: The cooling tower comprises a cooling tower body, a cooling circulation fan and a water replenishment mechanism connected to the cooling tower body.

6. A carbon dioxide energy storage system, characterized in that: It comprises an air storage unit, an energy storage component, a liquid storage unit and an energy release component which are sequentially connected in a closed loop, and also comprises a unit cooling device as described in any one of claims 1-5.

7. The carbon dioxide energy storage system according to claim 6, characterized in that: The outlet of the liquid storage unit is connected to a booster pump, and the second evaporator is connected in parallel with the first evaporator between the booster pump and the energy release component.

8. A control method for a carbon dioxide energy storage system according to claim 6 or 7, characterized in that: The control method comprises: S100, when the carbon dioxide energy storage system is in an energy storage state, using the first cooling cycle loop to cool the system unit via the unit equipment heat exchanger; S200, when the carbon dioxide energy storage system is in an energy release condition, detecting and determining whether the temperature of the circulating water after heat exchange through the unit equipment heat exchanger exceeds the critical temperature of carbon dioxide: if not, using the first cooling circulation loop to cool the system unit through the unit equipment heat exchanger; if yes, using the second cooling circulation loop to cool the system unit through the unit equipment heat exchanger; Wherein, in the step S200: when the first cooling circulation loop is used for cooling, the liquid storage unit inputs liquid carbon dioxide into the first evaporator, and after evaporating through the first evaporator to form gaseous carbon dioxide, it is input into the energy release component; when the second cooling circulation loop is used for cooling, the liquid storage unit inputs liquid carbon dioxide into the first evaporator and the second evaporator respectively, and after evaporating through the first evaporator and the second evaporator respectively to form gaseous carbon dioxide, it is input into the energy release component.

9. The control method according to claim 8, characterized in that: The step S200 specifically includes: S201, when the energy release condition of the carbon dioxide energy storage system starts to start operation, using the first cooling cycle loop to cool the system unit via the unit equipment heat exchanger; S202, when the energy release condition of the carbon dioxide energy storage system is in full load operation, and the temperature of the circulating water after heat exchange through the unit equipment heat exchanger exceeds the critical temperature of carbon dioxide, using the second cooling circulation loop to cool the system unit through the unit equipment heat exchanger; S203: When the carbon dioxide energy storage system begins to reduce load in the energy release condition and is ready to stop running, the first cooling cycle loop is used to cool the system unit via the unit equipment heat exchanger.

10. The control method according to claim 8 or 9, characterized in that: When cooling is performed using the second cooling cycle, the flow of liquid carbon dioxide input to the second evaporator is controlled and the temperature of the gaseous carbon dioxide output from the second evaporator is monitored to ensure that the temperature of the gaseous carbon dioxide output from the second evaporator reaches above the critical temperature.

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