Compressed air energy storage system with recoverable condensate and method of replenishing water

Abstract

The application discloses a compressed air energy storage system capable of recycling condensate water and a water supplement method thereof, and belongs to the technical field of energy storage systems. The compressed air energy storage system capable of recycling condensate water comprises an energy storage unit, an energy release unit, a gas storage, a cooling tower and a liquid return pipeline. The energy storage unit comprises at least one energy storage unit, and the energy storage unit comprises a compressor, a first heat exchanger, a second heat exchanger and a gas-liquid separator which are sequentially connected. The second heat exchanger is configured as a gas-water heat exchanger. The cooling tower is communicated with the second heat exchanger and supplements cooling water to the second heat exchanger. One end of the liquid return pipeline is communicated with the gas-liquid separator, and the other end is communicated with the cooling tower. Thus, during the energy storage process, air can be separated from condensed water through the gas-liquid separator. The condensed water is sent to the cooling tower through the liquid return pipeline to supplement water to the cooling tower and is used for heat exchange of the second heat exchanger. Therefore, the condensed water separated during the compression process can be fully recycled and utilized, the water resource utilization rate can be improved, and the problem of water resource shortage can be optimized.

Description

Technical Field

[0001] This application relates to the field of energy storage system technology, and in particular to a compressed air energy storage system with recyclable condensate and a water replenishment method thereof. Background Technology

[0002] As the penetration rate of new energy power generation increases, the "dual-high" characteristics of the new power system—namely, a high proportion of renewable energy and a high proportion of power electronic equipment integration—are becoming increasingly prominent, making the demand for new energy storage technologies with long lifecycles and high security more urgent. Among various energy storage technologies, compressed air energy storage is currently the main technology capable of achieving megawatt-level applications, second only to pumped hydro storage. It possesses stronger power system stability support capabilities and has outstanding advantages such as long-term energy storage, short construction cycle, environmental friendliness, and high security, making it an important carrier for building new power systems.

[0003] In related technologies, compressed air energy storage technology and applications mostly focus on improving system efficiency and comprehensive utilization of waste heat, while neglecting the problem of compressed air water separation treatment during the energy storage process. This results in a large waste of water resources, especially in water-scarce areas, which seriously exacerbates the water shortage. At the same time, the condensate from the compressed air can easily damage the equipment in contact with it, affecting its performance and lifespan, thereby reducing the system's operational stability and reliability. Summary of the Invention

[0004] This application aims to at least solve one of the technical problems existing in the related art. To this end, one objective of this application is to propose a compressed air energy storage system capable of recovering condensate. In the compressed air energy storage system capable of recovering condensate, during the energy storage process, air can pass through a gas-liquid separator to condense water. The condensate is then sent to a cooling tower through a return pipeline to replenish the cooling tower and is used for heat exchange in a second heat exchanger. This allows for the full recovery and utilization of the condensate produced during the compression process, improving water resource utilization and addressing the water scarcity problem.

[0005] This application also proposes a water replenishment method for an energy storage system.

[0006] According to an embodiment of the first aspect of this application, a compressed air energy storage system capable of recovering condensate water includes: an energy storage unit, an energy release unit, an air storage tank, a cooling tower, and a return liquid pipeline. The energy storage unit includes: at least one energy storage unit, which includes a compressor, a first heat exchanger, a second heat exchanger, and a gas-liquid separator connected in sequence. The second heat exchanger is configured as a gas-water heat exchanger. The air storage tank has a gas-side pipeline, which can be selectively connected to the energy storage unit for energy storage or to the energy release unit for energy release. The cooling tower is connected to the second heat exchanger and supplies cooling water to the second heat exchanger. One end of the return liquid pipeline is connected to the gas-liquid separator, and the other end is connected to the cooling tower to supply water to the cooling tower.

[0007] According to the compressed air energy storage system with recyclable condensate of this application, a gas-liquid separator is used to separate condensate from the compressed air, and the condensate is transported to a cooling tower through a return pipeline to replenish the cooling tower. This ensures that the cooling tower continuously provides cooling water to the second heat exchanger for heat exchange, thereby achieving full recycling of condensate from the compression process, improving water resource utilization, and effectively alleviating water scarcity. Furthermore, separating and removing moisture from the compressed air improves air dryness, which helps protect the compressor and other equipment from moisture damage, thus improving equipment performance and lifespan. This enhances the operational stability and reliability of the compressed air energy storage system with recyclable condensate, while also improving exhaust air quality and environmental friendliness.

[0008] According to some embodiments of this application, the second heat exchanger includes a cooling water inlet and a cooling water outlet, wherein the cooling water inlet is connected to the cooling tower outlet via a first pipeline, and the cooling water outlet is connected to the cooling tower inlet via a second pipeline.

[0009] Furthermore, the cooling tower is equipped with a first water pump, which is located at the inlet and / or outlet of the cooling tower and is adapted to be connected to the first pipeline or the second pipeline.

[0010] In some embodiments, when there are multiple energy storage units, multiple first pipelines are connected in parallel and multiple second pipelines are connected in parallel.

[0011] According to some embodiments of this application, the return pipeline includes a return pipe and a second water pump, the return pipe being connected to the second water pump, and the second water pump being used to replenish water to the cooling tower.

[0012] Furthermore, the return pipe is constructed as a buried pipe.

[0013] In some embodiments, the return pipeline further includes a filter disposed between the return pipeline and the cooling tower, and adapted to filter the water returning from the return pipeline.

[0014] According to some embodiments of this application, the compressed air energy storage system for recovering condensate further includes: a liquid storage tank, and the return pipeline further includes: a first branch and a second branch, one end of the first branch being connected to the filter and the other end being connected to the cooling tower, and one end of the second branch being connected to the filter and the other end being connected to the liquid storage tank.

[0015] Furthermore, the return pipeline also includes a third branch, one end of which is connected to the storage tank and the other end of which is connected to the cooling tower. The third branch is equipped with a third water pump for replenishing water from the storage tank to the cooling tower.

[0016] In some embodiments, a first valve is provided on the first branch and a second valve is provided on the second branch.

[0017] Furthermore, the cooling tower is also equipped with a liquid level sensor, which is electrically connected to the first valve and the second valve and is adapted to control the selective opening and closing of the first valve and the second valve.

[0018] According to some embodiments of this application, the energy release unit includes at least one energy release unit, the energy release unit including an expander and a heater connected in sequence.

[0019] According to some embodiments of this application, the compressed air energy storage system for recovering condensate further includes: a low-temperature heat storage device and a high-temperature heat storage device, both of which are connected to the heater and the first heat exchanger.

[0020] The water replenishment method for an energy storage system according to the second aspect of this application is applicable to any of the above embodiments of a compressed air energy storage system capable of recovering condensate. The water replenishment method for the energy storage system includes: obtaining the liquid level of a cooling tower; if the liquid level reaches a first threshold, opening a first valve and closing a second valve to replenish water to the cooling tower; if the liquid level reaches a second threshold, opening the second valve and closing the first valve to supply water to a storage tank; wherein the first threshold is lower than the second threshold.

[0021] Furthermore, the water replenishment method of the energy storage system also includes: if the energy storage unit stops storing energy when the liquid level reaches the first threshold, the liquid storage tank replenishes water to the cooling tower until the liquid level reaches the second threshold.

[0022] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0023] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0024] Figure 1 This is a schematic diagram of a compressed air energy storage system for recyclable condensate according to some embodiments of this application;

[0025] Figure 2 This is a schematic flowchart of a water replenishment method for an energy storage system according to some embodiments of this application.

[0026] Figure label:

[0027] 100. Compressed air energy storage system with recyclable condensate;

[0028] 11. Compressor; 12. First heat exchanger; 13. Second heat exchanger; 14. Gas-liquid separator;

[0029] 21. Expander; 22. Heater;

[0030] 30. Gas storage facility;

[0031] 40. Cooling tower; 41. First pipeline; 42. Second pipeline; 43. First water pump; 44. Liquid level sensor;

[0032] 51. Return pipe; 52. Second water pump; 53. Filter; 54. First branch; 55. Second branch; 56. Third branch; 57. Third water pump; 58. First valve; 59. Second valve;

[0033] 60. Liquid storage tank;

[0034] 70. Low-temperature thermal storage unit;

[0035] 80. High-temperature heat storage tank;

[0036] 91. Electric motor; 92. Generator. Detailed Implementation

[0037] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0038] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used in the description of this application is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms "comprising" and "having," and any variations thereof, in the description, claims, and accompanying drawings of this application are intended to cover non-exclusive inclusion. The terms "first," "second," etc., in the description, claims, or accompanying drawings of this application are used to distinguish different objects, not to describe a specific order or hierarchy.

[0039] In this application, the reference to "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment that is mutually exclusive with other embodiments.

[0040] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "attachment" 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 direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0041] In this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, in this application, the character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0042] In the embodiments of this application, the same reference numerals denote the same components, and for the sake of brevity, detailed descriptions of the same components are omitted in different embodiments. It should be understood that the thickness, length, width, and other dimensions of various components in the embodiments of this application shown in the accompanying drawings, as well as the overall thickness, length, width, and other dimensions of the integrated device, are merely illustrative and should not constitute any limitation on this application.

[0043] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0044] In the description of this application, the first feature being "above" or "below" the second feature may include the first and second features being in direct contact, or the first and second features being in contact through another feature between them.

[0045] In the description of this application, the terms "above," "over," and "on top" for the first feature and the second feature include the first feature being directly above or diagonally above the second feature, or simply indicate that the first feature is at a higher horizontal level than the second feature.

[0046] In this application, "multiple" means two or more (including two).

[0047] The following is for reference. Figure 1 and Figure 2 This application describes a compressed air energy storage system 100 with recyclable condensate and a water replenishment method for the energy storage system, according to embodiments of the present application.

[0048] like Figure 1 As shown, the compressed air energy storage system 100 with recyclable condensate according to the first aspect embodiment of this application includes: an energy storage unit, an energy release unit, an air storage tank 30, a cooling tower 40, and a liquid return pipeline.

[0049] The energy storage unit includes: at least one energy storage unit, which includes a compressor 11, a first heat exchanger 12, a second heat exchanger 13, and a gas-liquid separator 14 connected in sequence. The second heat exchanger 13 is configured as a gas-water heat exchanger. The gas storage tank 30 has a gas-side pipeline, which can be selectively connected to the energy storage unit to store energy or connected to the energy release unit to release energy. The cooling tower 40 is connected to the second heat exchanger 13 and replenishes the second heat exchanger 13 with cooling water. One end of the return liquid pipeline is connected to the gas-liquid separator 14, and the other end is connected to the cooling tower 40 to replenish the cooling tower 40 with water.

[0050] Specifically, the gas storage unit 30 can be selectively connected to an energy storage unit or an energy release unit via a gas-side pipeline to realize the energy storage and energy release of the compressed air energy storage system 100 with recoverable condensate, respectively. The energy storage unit may include one or more energy storage units, each energy storage unit including a compressor 11, a first heat exchanger 12, a second heat exchanger 13, and a gas-liquid separator 14 connected in sequence, wherein the second heat exchanger 13 is configured as a gas-water heat exchanger. During energy storage, air first enters compressor 11. Compressor 11 compresses the air to high pressure to store excess electricity from equipment such as motor 91 under low load. A large amount of heat is generated during compression, which is recovered and stored by the first heat exchanger 12 for later use. Then, the high-pressure air enters the second heat exchanger 13, i.e., the gas-water heat exchanger. The gas-water heat exchanger uses cooling water to lower the air temperature and heat the cooling water at the same time to achieve energy transfer. The cooled air enters the gas-liquid separator 14, where water and liquid substances are separated, and the dry high-pressure gas is stored in the gas storage tank 30 for energy storage. When energy needs to be released, the high-pressure air in the gas storage tank 30 enters the energy release unit through the gas-side pipeline. In the energy release unit, the compression heat stored in the first heat exchanger 12 during energy storage can be used to heat the air to improve energy storage efficiency. The high-pressure air is converted into electrical energy or other forms of energy through heating and expansion to enable equipment such as generator 92 to operate, thereby realizing the reuse of the stored energy.

[0051] It should be noted that the compressed air energy storage system 100 with recoverable condensate in this application includes a cooling tower 40 and a return liquid pipeline. The cooling tower 40 is adapted to replenish cooling water to the second heat exchanger 13 in the energy storage unit for heat exchange with the compressed air. One end of the return liquid pipeline is connected to the gas-liquid separator 14 in the energy storage unit, and the other end is connected to the cooling tower 40. The return liquid pipeline can send the water and liquid substances separated in the gas-liquid separator 14 to the cooling tower 40 to replenish the cooling tower 40 with water for use as circulating cooling water, thereby realizing the recovery and utilization of condensate precipitated during the compression process in the energy storage process.

[0052] According to the compressed air energy storage system 100 with recyclable condensate water of this application, condensate water in the compressed air is separated by a gas-liquid separator 14 and transported to a cooling tower 40 through a return liquid pipeline to replenish the cooling tower 40. This allows the cooling tower 40 to continuously provide cooling water to the second heat exchanger 13 for heat exchange, thereby achieving full recycling of condensate water separated during the compression process, improving water resource utilization, and effectively alleviating water scarcity. Furthermore, separating and removing moisture from the compressed air improves air dryness, which also helps protect the compressor 11 and other equipment from moisture damage, improving equipment performance and lifespan, enhancing the operational stability and reliability of the compressed air energy storage system 100 with recyclable condensate water, and improving exhaust air quality, thus enhancing environmental friendliness.

[0053] like Figure 1 As shown, according to some embodiments of this application, the second heat exchanger 13 includes a cooling water inlet and a cooling water outlet. The cooling water inlet is connected to the cooling tower outlet through a first pipe 41, and the cooling water outlet is connected to the cooling tower inlet through a second pipe 42.

[0054] Specifically, the cooling water inlet of the second heat exchanger 13 in each energy storage unit is connected to the cooling tower outlet via a first pipe 41. The cooling water, after being cooled by evaporation in the cooling tower 40, enters the cooling water inlet of the second heat exchanger 13 through the first pipe 41. Inside the heat exchanger, the cooling water exchanges heat with compressed hot air, absorbing heat from the air and thus lowering the air temperature. Simultaneously, the cooling water's own temperature rises. The cooling water outlet of the second heat exchanger 13 is connected to the cooling tower inlet via a second pipe 42. Thus, the cooled water, heated after heat exchange with the air, flows out from the cooling water outlet of the second heat exchanger 13 and returns to the cooling tower 40 through the second pipe 42. In the cooling tower 40, the cooling water undergoes evaporation cooling to prepare for the next round of heat exchange. The second heat exchanger 13 is connected to the cooling tower 40 through the first pipe 41 and the second pipe 42, which ensures the continuous circulation of cooling water in the compressed air energy storage system 100 with recoverable condensate, and makes full use of the evaporative cooling effect of the cooling tower 40 and the heat exchange capacity of the second heat exchanger 13, thereby achieving effective cooling of compressed air and improving the energy utilization efficiency of the entire system.

[0055] Furthermore, in some specific embodiments of this application, the temperatures of the cooling tower inlet and outlet are controlled within the range of approximately 30°C to 35°C. When the temperatures of the cooling tower inlet and outlet are much lower than 30°C, such as 20°C, 15°C, or 10°C, the excessively low temperatures mean that, under the condition that the first heat exchanger 12 remains unchanged, the cooling tower 40 may increase energy consumption to achieve the excessively low inlet and outlet temperatures, thus reducing the overall operating efficiency of the compressed air energy storage system 100 with recoverable condensate. When the temperatures of the cooling tower inlet and outlet are much higher than 35°C, such as 45°C, 50°C, or 55°C, the excessively high temperatures will result in poor cooling effect of the cooling water on the compressed air, or even failure to cool it, thereby reducing the thermal efficiency and energy storage density of the compressed air energy storage system 100 with recoverable condensate. By setting the temperatures of the cooling tower inlet and outlet to the ranges mentioned above, such as 30°C, 32°C, or 35°C, the temperatures of the cooling tower inlet and outlet are controlled within a suitable range. This helps ensure that the cooling water can effectively release heat when passing through the cooling tower 40, ensuring that the cooling tower 40 can effectively dissipate heat and maintain a suitable operating temperature. This is beneficial for optimizing the operating efficiency and stability of the compressed air energy storage system 100 that can recover condensate.

[0056] like Figure 1 As shown, according to some embodiments of this application, a first water pump 43 is provided on the cooling tower 40. The first water pump 43 is located at the cooling tower inlet and / or cooling tower outlet, and is adapted to be connected to a first pipeline 41 or a second pipeline 42.

[0057] Specifically, the cooling tower 40 may be equipped with a first water pump 43. The first water pump 43 can be configured such that it is only installed at the cooling tower inlet, and not at the cooling tower outlet; alternatively, it can be installed only at the cooling tower outlet, and not at the cooling tower inlet; or it can be installed at both the cooling tower inlet and outlet. The first water pump 43 provides power for the flow of cooling water, ensuring that the cooling water flows smoothly from the cooling tower outlet to the cooling water inlet of the second heat exchanger 13, and ensuring that the cooled water after heat exchange flows from the cooling water outlet of the second heat exchanger 13 to the cooling tower inlet, thereby ensuring the circulation of cooling water between the cooling tower 40 and the second heat exchanger 13.

[0058] Furthermore, in some embodiments, the first water pump 43 can also regulate the flow rate. For example, by adjusting the speed or opening degree of the first water pump 43, the flow rate of cooling water can be precisely controlled. This enhances the cooling water regulation capability of the compressed air energy storage system 100 with recoverable condensate under different operating conditions, improves its flexibility, meets the cooling requirements under different operating conditions, and helps ensure that the compressed air energy storage system 100 with recoverable condensate maintains optimal operating conditions under various conditions, thereby improving its efficiency. For example, in hot summer weather, the circulation speed and cooling effect of the cooling water can be increased by increasing the speed of the first water pump 43; while in cold winter weather, the speed of the first water pump 43 can be reduced to save energy and avoid overcooling.

[0059] like Figure 1 As shown, according to some embodiments of this application, when there are multiple energy storage units, multiple first pipelines 41 are connected in parallel and multiple second pipelines 42 are connected in parallel.

[0060] Specifically, the energy storage units can be configured in multiple ways to achieve higher air pressure through multiple air compressions, thereby storing more energy. When multiple energy storage units are configured, the first pipes 41 of the multiple energy storage units are connected in parallel, and the second pipes 42 of the multiple energy storage units are connected in parallel. For example, if there are two energy storage units, then two first pipes 41 are connected in parallel, and two second pipes 42 are connected in parallel; if there are three energy storage units, then three first pipes 41 are connected in parallel, and three second pipes 42 are connected in parallel. By arranging the multiple first pipes 41 in parallel, the cooling water inlet of the second heat exchanger 13 of each energy storage unit is connected to the cooling tower outlet, ensuring that the second heat exchanger 13 of each energy storage unit can obtain cooling water from the cooling tower 40. By connecting multiple second pipelines 42 in parallel, the cooling water outlet of the second heat exchanger 13 of each energy storage unit is connected to the inlet of the cooling tower. This ensures that the cooling water after heat exchange in the second heat exchanger 13 of each energy storage unit can flow smoothly back to the cooling tower 40 for cooling, preparing for the next round of cooling of the second heat exchanger 13. Thus, by connecting multiple first pipelines 41 in parallel and multiple second pipelines 42 in parallel, the cooling needs of each energy storage unit can be fully met, effectively improving the thermal efficiency of the entire compressed air energy storage system 100 with recoverable condensate.

[0061] Furthermore, the parallel connection of multiple first pipelines 41 and multiple second pipelines 42 can improve the flexibility and scalability of the compressed air energy storage system 100 with recyclable condensate. When a new energy storage unit needs to be added, only the corresponding first pipeline 41, second pipeline 42 and connectors need to be added, without the need for large-scale modification of the existing compressed air energy storage system 100 with recyclable condensate.

[0062] like Figure 1 As shown, according to some embodiments of this application, the return pipeline includes a return pipe 51 and a second water pump 52. The return pipe 51 is connected to the second water pump 52, and the second water pump 52 is used to replenish water to the cooling tower 40.

[0063] Specifically, the two ends of the return pipe 51 are connected to the gas-liquid separator 14 and the cooling tower 40, respectively, to provide a flow channel for the liquid separated by the gas-liquid separator 14. The second water pump 52 is connected to the return pipe 51 to provide power for the liquid in the return pipe 51, so as to ensure that the liquid can be quickly and effectively delivered to the cooling tower 40 when needed. For example, when the cooling water in the cooling tower 40 decreases due to evaporation, leakage or other reasons, the second water pump 52 can promptly pump the liquid flowing from the gas-liquid separator 14 into the return pipe 51 to the cooling tower 40 to replenish the cooling tower 40 with water, thereby maintaining the normal cooling water volume of the cooling tower 40 and ensuring the good cooling effect of the second heat exchanger 13.

[0064] Similarly, in some embodiments, the second water pump 52 can also play the role of regulating flow rate. By adjusting the speed or opening degree of the second water pump 52, the liquid flow rate in the return pipeline can be precisely controlled to meet the cooling requirements under different operating conditions, thereby improving the flexibility and adaptability of the compressed air energy storage system 100 that can recover condensate.

[0065] like Figure 1 As shown, according to some embodiments of this application, the return pipe 51 is constructed as a buried pipe.

[0066] Specifically, the return pipe 51 can be constructed as a buried pipe, which refers to a pipe installed underground that can utilize the natural heat capacity of the underground soil or rock for heat exchange to achieve heat dissipation or heat absorption of the liquid inside the pipe. In heat dissipation mode, when the liquid separated by the gas-liquid separator 14 flows into the buried pipe, the buried pipe can transfer the heat of the liquid inside the pipe to the soil, thereby cooling the liquid. In heat absorption mode, the buried pipe absorbs heat from the soil, heating the liquid inside the pipe and raising its temperature. By constructing the return pipe 51 as a buried pipe, firstly, due to the relatively large natural heat capacity of soil or rock, heat exchange between the buried pipe and the underground soil can enable the liquid to rapidly absorb or release heat, thus achieving efficient heat exchange; secondly, the buried pipe utilizes the heat capacity of the natural environment such as soil or rock, requiring no additional energy input, thus effectively saving energy consumption. Furthermore, since the buried pipe is underground, its impact on the surface landscape and ecological environment is relatively small, aligning with the green and environmentally friendly sustainable development concept; thirdly, compared to surface temperature, underground temperature is more stable. Therefore, in climates with varying temperatures throughout the four seasons, the soil can provide stable temperature control for the buried pipe, thereby improving the temperature stability of the liquid flowing from the buried pipe into the cooling tower 40, which is beneficial for improving the thermal efficiency and operational stability of the compressed air energy storage system 100 with recoverable condensate.

[0067] Furthermore, in some specific embodiments of this application, the buried pipe is constructed of steel, high-density polyethylene, or polyvinyl chloride. Steel, high-density polyethylene, and polyvinyl chloride have advantages such as good corrosion resistance, high strength, and good thermal conductivity, which are beneficial to improving the heat exchange performance and lifespan of the buried pipe during long-term use.

[0068] like Figure 1 As shown, according to some embodiments of this application, the return pipeline further includes a filter 53, which is disposed between the return pipeline 51 and the cooling tower 40 and is adapted to filter the water returning from the return pipeline 51.

[0069] Specifically, filter 53 is located between return pipe 51 and cooling tower 40, that is, before liquid flows from gas-liquid separator 14 into return pipe 51 and enters cooling tower 40. When liquid flows from return pipe 51 into filter 53, impurities and contaminants in the liquid can be trapped by the filter screen or filter media inside filter 53, while the filtered pure water continues to flow and enters cooling tower 40 for further cooling treatment. By installing a filter 53 between the return pipe 51 and the cooling tower 40, the liquid is ensured to be filtered before entering the cooling tower 40, thereby improving the purity of the liquid entering the cooling tower 40. This has two advantages: firstly, it helps ensure good flow and stability of the cooling water, thus improving the stability and reliability of the entire compressed air energy storage system 100 with recoverable condensate; secondly, it can prevent impurities and contaminants in the liquid before filtration from clogging and damaging the cooling tower 40 and the second heat exchanger 13, thus helping to ensure the performance and service life of the cooling tower 40 and the second heat exchanger 13, and ensuring the stable operation and high efficiency of the compressed air energy storage system 100 with recoverable condensate.

[0070] In some embodiments, filters 53 can be configured as multiple filters, each of different types. For example, at least one of the multiple filters 53 can be configured as a mechanical filter to remove suspended solids, particulate matter, etc. from the liquid; at least another of the multiple filters 53 can be configured as an activated carbon filter to remove organic matter, residual chlorine, and other chemical contaminants from the liquid; and at least one of the multiple filters 53 can be configured as a precision filter to further remove tiny particles and bacteria. By coordinating different types of filters 53, the filtration effect can be further enhanced, and the cleanliness of the liquid in the return pipe 51 can be further improved.

[0071] like Figure 1 As shown, according to some embodiments of this application, the compressed air energy storage system 100 for recovering condensate water further includes: a liquid storage tank 60, and the return pipeline further includes: a first branch 54 and a second branch 55, one end of the first branch 54 is connected to a filter 53 and the other end is connected to a cooling tower 40, one end of the second branch 55 is connected to a filter 53 and the other end is connected to the liquid storage tank 60.

[0072] Specifically, the first branch 54 in the return liquid pipeline is connected to the filter 53 and the cooling tower 40 at both ends, respectively. The first branch 54 is used to transport the filtered liquid in the return liquid pipeline 51 to the cooling tower 40. The second branch 55 in the return liquid pipeline is connected to the filter 53 and the storage tank 60 at both ends, respectively. The second branch 55 is used to transport the filtered liquid to the storage tank 60 for storage and standby. During the energy storage stage, the gas-liquid separator 14 in the energy storage unit separates the moisture from the compressed air and passes it through the return liquid pipeline 51 into the filter 53 for filtration. The filtered moisture can have two flow paths: the first path is through the first branch 54 into the cooling tower 40 for circulating water to the second heat exchanger 13; the second path is through the second branch 55 into the storage tank 60 for storage and standby. The specific flow path of the filtered water can be determined based on the water volume in the cooling tower 40. Specifically, the condensate that has been separated and filtered during the compression process can first flow into the cooling tower 40 along the first path to replenish the cooling tower 40. When the water volume in the cooling tower 40 reaches a preset upper limit, the return pipe 51 completes the replenishment of water to the cooling tower 40. If the compression process is not yet finished, the excess condensate that has been separated and filtered during the compression process will enter the storage tank 60 along the second path for storage, to be used as a backup water source for the compressed air energy storage system 100 with recoverable condensate. Through the multi-branch configuration of the first branch 54 and the second branch 55, flexible scheduling of the recovered condensate can be achieved, which can further optimize water resource utilization and help improve the cooling efficiency and stability of the compressed air energy storage system 100 with recoverable condensate.

[0073] like Figure 1 As shown, according to some embodiments of this application, the return pipeline further includes a third branch 56, one end of which is connected to the storage tank 60 and the other end is connected to the cooling tower 40. The third branch 56 is equipped with a third water pump 57 for replenishing water from the storage tank 60 to the cooling tower 40.

[0074] Specifically, the two ends of the third branch 56 in the return pipeline are connected to the storage tank 60 and the cooling tower 40 respectively, and the third branch 56 is equipped with a third water pump 57. Driven by the third water pump 57, the water stored in the storage tank 60 can be directly pumped to the cooling tower 40 through the third branch 56 to replenish the cooling tower 40 in a timely manner, thereby maintaining sufficient water volume in the cooling tower 40.

[0075] Understandably, during the energy storage phase, cooling tower 40 can first utilize the circulating cooling water flowing through the second heat exchanger 13 and the water separated by the gas-liquid separator 14 to replenish and ensure the water volume within cooling tower 40. The third branch 56 serves as a backup water replenishment path to cooling tower 40, and it is not limited to either the energy storage phase or the non-energy storage phase. For example, during the energy storage phase, if the rate of water replenishment through the recovery of water separated by the gas-liquid separator 14 is relatively slow, the water stored in the storage tank 60 can be appropriately introduced into cooling tower 40 to accelerate the water replenishment rate. After energy storage is completed, i.e., during the non-energy storage phase, if the water volume in cooling tower 40 is lower than the preset upper limit due to insufficient condensate recovery caused by short compression time, or due to evaporation or other reasons, the water stored in the storage tank 60 can also be added to cooling tower 40 to bring the water volume within cooling tower 40 back to the preset upper limit.

[0076] By using the storage tank 60 to store the excess water released during the compression process as a backup water supply for the cooling tower 40, it is possible to ensure that the cooling tower 40 always has sufficient water to guarantee the overall thermal efficiency and operational reliability of the compressed air energy storage system 100 with recoverable condensate, while also making full use of and optimizing the configuration of the condensate released during the compression process.

[0077] like Figure 1 As shown, according to some embodiments of this application, a first valve 58 is provided on the first branch 54, and a second valve 59 is provided on the second branch 55.

[0078] Specifically, the first valve 58 is located in the first branch 54, and can be used to open, close, and control the flow of the first branch 54. Similarly, the second valve 59 is located in the second branch 55, and can be used to open, close, and control the flow of the second branch 55. When the first valve 58 is open and the second valve 59 is closed, the filter 53 is connected to the cooling tower 40, and the filter 53 is closed to the storage tank 60. The liquid in the return pipe 51, after being filtered by the filter 53, flows to the cooling tower 40 to replenish water. Conversely, when the second valve 59 is open and the first valve 58 is closed, the filter 53 is connected to the storage tank 60, and the filter 53 is closed to the cooling tower 40. The liquid in the return pipe 51, after being filtered by the filter 53, flows to the storage tank 60 for storage and backup. By switching the opening and closing states of the first valve 58 and the second valve 59, the return pipe 51 can be flexibly switched between replenishing water to the cooling tower 40 and providing storage water to the storage tank 60, which can effectively improve the working flexibility and reliability of the compressed air energy storage system 100 that can recover condensate.

[0079] Furthermore, by adjusting the first valve 58, precise control of the flow rate in the first branch 54 can be achieved. By controlling the opening of the second valve 59, precise control of the flow rate in the second branch 55 can be achieved, thereby controlling the rate at which the return pipe 51 replenishes water to the cooling tower 40 and the storage tank 60. For example, when a relatively large amount of water is released during the compression process of the energy storage unit, and the flow rate in the return pipe 51 is high, while the water volume in the cooling tower 40 approaches the preset upper limit, the opening of the first valve 58 can be appropriately reduced to slow down the flow rate and speed of the liquid flowing to the cooling tower 40, thereby improving the accuracy of controlling the water volume in the cooling tower 40 to reach the preset upper limit. By adjusting the opening of the first valve 58 and the second valve 59, the flow path and flow rate of the condensate recovered during the energy storage stage can be flexibly scheduled, further optimizing the cooling effect and resource utilization.

[0080] like Figure 1 As shown, according to some embodiments of this application, a liquid level sensor 44 is also provided on the cooling tower 40. The liquid level sensor 44 is electrically connected to the first valve 58 and the second valve 59, and is adapted to control the selective opening and closing of the first valve 58 and the second valve 59.

[0081] Specifically, a liquid level sensor 44 is installed on the cooling tower 40. The liquid level sensor 44 can monitor the liquid level of the cooling water in the cooling tower 40 in real time. The liquid level sensor 44 is electrically connected to both the first valve 58 and the second valve 59. The liquid level sensor 44 can convert the detected liquid level in the cooling tower 40 into an electrical signal and send it to the control system. The control system automatically adjusts the opening of the first valve 58 and the second valve 59 according to a preset logic algorithm to achieve timely replenishment and reasonable distribution of cooling water. For example, when the liquid level sensor 44 detects that the liquid level in the cooling tower 40 is lower than the preset upper limit, it can control the first valve 58 to open and the second valve 59 to close, so that the condensate precipitated during the compression process flows only into the cooling tower 40 after filtration, thus ensuring rapid water replenishment of the cooling tower 40. When the liquid level sensor 44 detects that the liquid level in the cooling tower 40 reaches the preset upper limit, it can control the first valve 58 to close and the second valve 59 to open, so that the condensate precipitated during the compression process flows to the storage tank 60 after filtration and is stored in the storage tank 60 as a backup water source.

[0082] By setting up a liquid level sensor 44, the liquid level of the cooling tower 40 is monitored in real time and the opening and closing status of the valves is automatically adjusted, which realizes precise control and automated management of the cooling water flow. This helps to improve the overall reliability of the system and ensures that the cooling tower 40 can obtain sufficient cooling medium at all times. This helps to improve cooling efficiency, ensures that the energy storage unit can operate continuously and efficiently, and also facilitates the full utilization of cooling water.

[0083] like Figure 1As shown, according to some embodiments of this application, the energy release unit includes at least one energy release unit, which includes an expander 21 and a heater 22 connected in sequence.

[0084] Specifically, the energy release unit may include one or more energy release units, each of which includes an expander 21 and a heater 22, with the heater 22 and expander 21 connected in sequence (e.g., via pipes or connecting devices) to ensure smooth air flow between them. During the energy release phase, the air compressed in the energy storage phase can be heated by the heater 22 and expanded by the expander 21, thereby releasing energy and converting it into mechanical or electrical energy. Ultimately, the energy output by the compressed air energy storage system 100, which can recover condensate, can be supplied to the power grid, used to drive mechanical equipment, or used for other purposes to achieve the reuse of the stored energy.

[0085] It should be noted that the heat used by the heater 22 to heat the air can come from the compressed heat recovered and stored by the first heat exchanger 12 in the energy storage stage, thereby realizing the full utilization of the compressed heat and effectively improving the thermal efficiency of the compressed air energy storage system 100 with recoverable condensate.

[0086] Furthermore, in some specific embodiments of this application, the energy storage unit includes two energy storage units connected in series, namely a first energy storage unit and a second energy storage unit. Both the first and second energy storage units include a compressor 11, a first heat exchanger 12, a second heat exchanger 13, and a gas-liquid separator 14 connected in series. The energy release unit includes two energy release units connected in series, namely a first energy release unit and a second energy release unit. Both the first and second energy release units include an expander 21 and a heater 22 connected in series. During the energy storage phase, air undergoes two compressions, heat exchange, cooling, and gas-liquid separation via the first and second energy storage units, allowing the gas to reach higher pressure and thus store more energy. During the energy release phase, the gas undergoes two heatings and expansions via the first and second energy release units, allowing the expansion process to release more energy, thereby increasing the output of energy in the form of electrical or mechanical energy.

[0087] like Figure 1 As shown, according to some embodiments of this application, the compressed air energy storage system 100 with recyclable condensate further includes: a low-temperature heat storage device 70 and a high-temperature heat storage device 80.

[0088] The low-temperature heat storage device 70 and the high-temperature heat storage device 80 are both connected to the heater 22 and the first heat exchanger 12.

[0089] Specifically, in this embodiment, the high-temperature heat storage device 80 can be used to store a high-temperature heat storage medium, and the low-temperature heat storage device 70 can be used to store a low-temperature heat storage medium. Both the low-temperature heat storage device 70 and the high-temperature heat storage device 80 are connected to the heater 22 and the first heat exchanger 12, thus the low-temperature heat storage device 70 and the high-temperature heat storage device 80 are connected through the first heat exchanger 12 and the heater 22. The high-temperature heat storage device 80, the low-temperature heat storage device 70, the first heat exchanger 12 and the heater 22 work together to achieve a high-efficiency thermal cycle of the compressed air energy storage system 100 with recoverable condensate. Its working principle is as follows: In the energy storage stage, a large amount of heat is generated during the compression of air. The low-temperature heat storage medium in the low-temperature heat storage device 70 flows through the first heat exchanger 12 to exchange heat with the air and becomes a high-temperature heat storage medium stored in the high-temperature heat storage device 80. In the energy release stage, the high-temperature heat storage medium in the high-temperature heat storage device 80 passes through the heater 22 and heats the gas, while becoming a low-temperature heat storage medium and flowing into the low-temperature heat storage device 70 for continued use in the next energy storage stage.

[0090] In some specific embodiments of this application, the heat storage medium material in the high-temperature heat storage device 80 and the low-temperature heat storage device 70 is constructed as pressurized water or heat transfer oil. Pressurized water and heat transfer oil have advantages such as high heat capacity, good thermal conductivity, and relatively low cost. By constructing the heat storage medium material in the high-temperature heat storage device 80 and the low-temperature heat storage device 70 as pressurized water or heat transfer oil, it is beneficial to ensure the stability and effectiveness of the stored thermal energy in the high-temperature heat storage device 80 and the low-temperature heat storage device 70, and save costs, thereby improving the overall performance, safety, and economy of the compressed air energy storage system 100 with recoverable condensate.

[0091] According to the compressed air energy storage system 100 with recyclable condensate of this application, the overall working principle is as follows: During the compression process, air enters the first compressor 11 and is compressed into high-pressure, high-temperature air. Then, it enters the first heat exchanger 12 to exchange heat with the low-temperature heat storage medium from the low-temperature heat storage tank, cooling the high-pressure, high-temperature air to approximately 50°C. Afterward, it passes through the first and second heat exchangers 13 for further cooling, and then passes through the first gas-liquid separator 14 to separate dry air and condensate. Similarly, the separated high-pressure air then sequentially passes through the second compressor 11, the second first heat exchanger 12, and the second second heat exchanger 13 for compression and heat exchange, and condensate is separated using the second gas-liquid separator 14. In other words, the air undergoes two compression, heat exchange, cooling, and gas-liquid separation processes before entering the air storage tank 30 for storage. When energy release is required, the dry air sequentially enters the first heater 22, the first expander 21, the second heater 22, and the second expander 21 for heating and expansion to generate electricity.

[0092] The compressed air energy storage system 100 with recoverable condensate according to this application has three functional paths. The first functional path is the air path, where outside air is compressed by the energy storage unit and flows into the gas storage tank 30 through the gas-side pipeline for storage. The gas stored in the gas storage tank 30 then flows to the energy release unit through the gas-side pipeline to realize the energy storage and release of the compressed air energy storage system 100 with recoverable condensate. The second functional path is the water replenishment path, where cooling water is replenished to the second heat exchanger 13 by the cooling tower 40 and connected to the gas-liquid separator 14 through the return liquid pipeline to recover the condensate separated from the compressed air and return the liquid. The pipeline can be selectively connected to the cooling tower 40 and the liquid storage tank 60 to rationally allocate the recovered condensate to the cooling tower 40 for water replenishment or to the liquid storage tank 60 for storage and backup, thereby realizing the full reuse of water resources in the compressed air energy storage system 100 with recoverable condensate; the third functional path is the heat storage medium path, based on the heat storage medium stored in the high temperature heat storage device 80 and the low temperature heat storage device 70, and flowing through the first heat exchanger 12 and the heater 22 according to different stages of the compressed air energy storage system 100 with recoverable condensate, thereby realizing the efficient heat cycle of the compressed air energy storage system 100 with recoverable condensate.

[0093] like Figure 2 As shown, the water replenishment method for the energy storage system according to the second aspect of this application is applicable to the energy storage system 100 in any of the above embodiments. The water replenishment method for the energy storage system includes: obtaining the liquid level of the cooling tower 40; if the liquid level reaches a first threshold, opening a first valve 58 and closing a second valve 59 to replenish water to the cooling tower 40; if the liquid level reaches a second threshold, opening the second valve 59 and closing the first valve 58 to supply water to the storage tank 60; wherein the first threshold is lower than the second threshold.

[0094] Specifically, according to the water replenishment method of the energy storage system according to the second aspect of the present application, the determination criteria for opening and closing the first valve 58 and the second valve 59 can be based on whether the liquid level of the cooling tower 40 reaches the first threshold and the second threshold. The first threshold is lower than the second threshold. The first threshold can be understood as a preset lower limit value of the water volume in the cooling tower 40, and the second threshold can be understood as a preset upper limit value of the water volume in the cooling tower 40. When the liquid level reaches the first threshold, it means that the water volume in the cooling tower 40 has decreased to the preset lower limit. The first valve 58 is then opened, and the second valve 59 is closed. The first branch 54 is opened, and the second branch 55 is closed. The condensate from the gas-liquid separator 14 flows into the cooling tower 40 to replenish the water volume, ensuring that the cooling tower 40 always has sufficient water, thereby guaranteeing the cooling effect and reliability of the second heat exchanger 13. When the liquid level reaches the second threshold, it means that the water volume in the cooling tower 40 has reached the preset upper limit, indicating that the cooling tower 40 has sufficient water. The second valve 59 is then opened, and the first valve 58 is closed. The second branch 55 is opened, and the first branch 54 is closed. The condensate from the gas-liquid separator 14 flows into the storage tank 60 to be stored and used as a backup water source for the cooling tower 40. This achieves multiple guarantees for the water volume of the cooling tower 40 and optimizes water resource utilization.

[0095] like Figure 2 As shown, according to some embodiments of this application, the water replenishment method of the energy storage system further includes: if the liquid level reaches a first threshold and the energy storage unit stops storing energy, the liquid storage tank 60 replenishes water to the cooling tower 40 until the liquid level reaches a second threshold.

[0096] Specifically, when the liquid level in the cooling tower 40 reaches the first threshold, the water volume in the cooling tower 40 decreases to a preset lower limit. If the energy storage unit stops storing energy and the gas-liquid separator 14 stops separating water, although the first valve 58 is open, the cooling tower 40 cannot continue to obtain water from the first branch 54. Then, the storage tank 60 can replenish water to the cooling tower 40 through the third branch 56 and the third water pump 57 until the liquid level in the cooling tower 40 reaches the second threshold, the water volume in the cooling tower 40 increases to a preset upper limit, and the storage tank 60 stops replenishing water. The remaining water in the storage tank 60 can be used as backup water for the next replenishment, thereby realizing the full and effective utilization of water resources in the compressed air energy storage system 100 with recoverable condensate.

[0097] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0098] Although embodiments of this application have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of this application, the scope of which is defined by the claims and their equivalents.

Claims

1. A compressed air energy storage system capable of recovering condensate, characterized in that, include: An energy storage unit, the energy storage unit comprising: at least one energy storage unit, the energy storage unit comprising a compressor (11), a first heat exchanger (12), a second heat exchanger (13) and a gas-liquid separator (14) connected in sequence, the second heat exchanger (13) being configured as a gas-water heat exchanger; Energy release unit; Gas storage tank (30), the gas storage tank (30) has a gas-side pipeline, the gas-side pipeline can be selectively connected to the energy storage unit to store energy, or connected to the energy release unit to release energy; The cooling tower (40) and the return pipeline are connected to the second heat exchanger (13) and the cooling tower (40) is supplied with cooling water. One end of the return pipeline is connected to the gas-liquid separator (14) and the other end is connected to the cooling tower (40) to supply water to the cooling tower (40). The return pipeline includes a return pipe (51) and a second water pump (52). The return pipe (51) is connected to the second water pump (52), and the second water pump (52) is used to replenish water to the cooling tower (40). The return pipeline also includes a storage tank (60) and a third branch (56), one end of which is connected to the storage tank (60) and the other end is connected to the cooling tower (40). The third branch (56) is equipped with a third water pump (57) for replenishing water from the storage tank (60) to the cooling tower (40).

2. The compressed air energy storage system with recyclable condensate as described in claim 1, characterized in that, The second heat exchanger (13) includes a cooling water inlet and a cooling water outlet. The cooling water inlet is connected to the cooling tower outlet through a first pipeline (41), and the cooling water outlet is connected to the cooling tower inlet through a second pipeline (42).

3. The compressed air energy storage system with recyclable condensate as described in claim 2, characterized in that, The cooling tower (40) is provided with a first water pump (43), which is located at the inlet and / or outlet of the cooling tower and is adapted to be connected to the first pipeline (41) or the second pipeline (42).

4. The compressed air energy storage system with recyclable condensate as described in claim 2 or 3, characterized in that, When there are multiple energy storage units, multiple first pipelines (41) are connected in parallel and multiple second pipelines (42) are connected in parallel.

5. The compressed air energy storage system with recyclable condensate as described in claim 1, characterized in that, The return pipe (51) is constructed as a buried pipe.

6. The compressed air energy storage system with recyclable condensate as described in claim 1, characterized in that, The return pipeline further includes a filter (53), which is disposed between the return pipeline (51) and the cooling tower (40) and is adapted to filter the water returning from the return pipeline (51).

7. The compressed air energy storage system with recyclable condensate as described in claim 6, characterized in that, The return pipeline further includes a first branch (54) and a second branch (55), one end of the first branch (54) is connected to the filter (53) and the other end is connected to the cooling tower (40), one end of the second branch (55) is connected to the filter (53) and the other end is connected to the storage tank (60).

8. The compressed air energy storage system with recyclable condensate as described in claim 7, characterized in that, A first valve (58) is provided on the first branch (54), and a second valve (59) is provided on the second branch (55).

9. The compressed air energy storage system with recyclable condensate as described in claim 8, characterized in that, The cooling tower (40) is also equipped with a liquid level sensor (44), which is electrically connected to the first valve (58) and the second valve (59) and is adapted to control the first valve (58) and the second valve (59) to selectively open and close.

10. The compressed air energy storage system with recyclable condensate as described in claim 1, characterized in that, The energy release unit includes at least one energy release unit, which includes an expander (21) and a heater (22) connected in sequence.

11. The compressed air energy storage system with recyclable condensate as described in claim 10, characterized in that, Also includes: Low-temperature heat storage device (70) and high-temperature heat storage device (80), both of which are connected to the heater (22) and the first heat exchanger (12).

12. A method for replenishing water in an energy storage system, applicable to the compressed air energy storage system with recyclable condensate as described in any one of claims 1-11, characterized in that, include: Obtain the liquid level in the cooling tower (40); When the liquid level reaches the first threshold, the first valve (58) is opened and the second valve (59) is closed to replenish water to the cooling tower (40); When the liquid level reaches the second threshold, the second valve (59) is opened and the first valve (58) is closed to supply water to the storage tank (60); whereby The first threshold is lower than the second threshold.

13. The water replenishment method for the energy storage system according to claim 12, characterized in that, Also includes: If the energy storage unit stops storing energy when the liquid level reaches the first threshold, the storage tank (60) will replenish water to the cooling tower (40) until the liquid level reaches the second threshold.

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