Heat pump supercritical carbon dioxide energy storage system

Abstract

The utility model relates to the technical field of energy storage, and provides a heat pump supercritical carbon dioxide energy storage system. The utility model provides a heat pump supercritical carbon dioxide energy storage system which comprises an energy storage circulating device and an energy storage device. The energy storage circulating device comprises a low-pressure supercritical carbon dioxide storage tank, a first compressor, an after-stage cooler, a high-pressure supercritical carbon dioxide storage tank and a turbo expander which are sequentially connected to form a closed loop; the energy storage device is connected with the stage aftercooler and used for storing compression heat released by the stage aftercooler. According to the heat pump supercritical carbon dioxide energy storage system, the designed energy storage circulating device and the energy storage device are integrated, and the technical problems that in the prior art, a carbon dioxide energy storage system is large in occupied area and low in energy storage efficiency are effectively solved.

Description

Technical Field

[0001] The utility model relates to the technical field of energy storage, in particular to a heat pump supercritical carbon dioxide energy storage system. Background Art

[0002] As the global energy system accelerates its transition to green and low-carbon, the demand for efficient and safe energy storage technologies has increased dramatically. Against this background, carbon dioxide energy storage technology, as a novel energy storage solution, is gradually emerging. One of its highlights is that its deployment is not restricted by geographical location and has little impact on the environment, so it has attracted widespread attention.

[0003] The core mechanism of carbon dioxide energy storage involves compressing the normal carbon dioxide gas into liquid form, and then converting it into electricity by driving a turbine expander through the gasification process of the liquid carbon dioxide. This technical path theoretically has high energy storage potential and is environmentally friendly.

[0004] However, since the existing technology stores carbon dioxide at normal temperature and pressure, it has low density and large volume. Therefore, it not only occupies a large area but also has low energy storage efficiency. Utility Model Content

[0005] The utility model provides a heat pump supercritical carbon dioxide energy storage system, which is used to solve the technical problems of a heat pump supercritical carbon dioxide energy storage system in the prior art that the system occupies a large area and has a low energy storage efficiency.

[0006] The utility model provides a heat pump supercritical carbon dioxide energy storage system, comprising an energy storage circulation device and an energy storage device; the energy storage circulation device comprises a low-pressure supercritical carbon dioxide storage tank, a first compressor, a stage aftercooler, a high-pressure supercritical carbon dioxide storage tank and a turbine expander which are sequentially connected to form a closed loop; the energy storage device is connected to the stage aftercooler and is used for storing compression heat released by the stage aftercooler.

[0007] According to one embodiment of the utility model, the after-stage cooler has a first heat exchange channel; the energy storage device includes a heat pump preheater, a high-temperature heat storage tank, a heat pump evaporator and a low-temperature heat storage tank; the inlet of the heat pump preheater is connected to the outlet of the high-pressure supercritical carbon dioxide storage tank, the outlet of the heat pump preheater is connected to the inlet of the turbine expander, and the heat pump preheater has a second heat exchange channel; the inlet of the high-temperature heat storage tank is connected to the outlet of the first heat exchange channel, and the outlet of the high-temperature heat storage tank is connected to the inlet of the second heat exchange channel.

[0008] According to one embodiment of the utility model, it also includes a heat pump circulation device; the heat pump evaporator is connected to the heat pump circulation device, the heat pump evaporator has a third heat exchange channel, the inlet of the third heat exchange channel is connected to the outlet of the second heat exchange channel, the outlet of the third heat exchange channel is connected to the inlet of the low-temperature heat storage tank; the outlet of the low-temperature heat storage tank is connected to the inlet of the first heat exchange channel.

[0009] According to one embodiment of the utility model, the heat pump circulation device includes a heat pump reheater, a heat pump throttling device and a second compressor; the inlet of the heat pump reheater is connected to the outlet of the heat pump preheater, the outlet of the heat pump reheater is connected to the inlet of the turbine expander, and the heat pump reheater has a third heat exchange channel; the inlet of the third heat exchange channel is connected to the outlet of the second compressor, and the outlet of the third heat exchange channel is connected to the inlet of the heat pump throttling device; the outlet of the heat pump throttling device is connected to the inlet of the heat pump evaporator; the inlet of the second compressor is connected to the outlet of the heat pump evaporator.

[0010] According to one embodiment of the utility model, the after-stage cooler has a first heat exchange channel; the energy storage device includes a heat pump preheater, a high-temperature heat storage tank, a heat pump evaporator and a low-temperature heat storage tank; a heat pump supercritical carbon dioxide energy storage system also includes a heat pump circulation device; the inlet of the heat pump preheater is connected to the outlet of the high-pressure supercritical carbon dioxide storage tank, the outlet of the heat pump preheater is connected to the inlet of the turbine expander, and the heat pump preheater has a second heat exchange channel; the inlet of the high-temperature heat storage tank is connected to the outlet of the first heat exchange channel, and the outlet of the high-temperature heat storage tank is connected to the heat pump circulation device.

[0011] According to one embodiment of the utility model, the inlet of the heat pump evaporator is connected to the heat pump circulation device, the outlet of the heat pump evaporator is connected to the inlet of the low-temperature heat storage tank, the heat pump evaporator has a third heat exchange channel, the inlet of the third heat exchange channel is connected to the outlet of the second heat exchange channel, and the outlet of the third heat exchange channel is connected to the heat pump circulation device; the outlet of the low-temperature heat storage tank is connected to the inlet of the first heat exchange channel.

[0012] According to one embodiment of the utility model, the heat pump circulation device includes a heat pump reheater, a heat pump throttling device and a second compressor; the inlet of the heat pump reheater is connected to the outlet of the heat pump preheater, the outlet of the heat pump reheater is connected to the inlet of the turbine expander, and the heat pump reheater has a third heat exchange channel; the inlet of the third heat exchange channel is connected to the outlet of the high-temperature heat storage tank, and the outlet of the third heat exchange channel is connected to the inlet of the heat pump evaporator; the inlet of the heat pump throttling device is connected to the outlet of the second heat exchange channel, and the outlet of the heat pump throttling device is connected to the inlet of the third heat exchange channel; the inlet of the second compressor is connected to the outlet of the third heat exchange channel, and the outlet of the second compressor is connected to the inlet of the second heat exchange channel.

[0013] According to one embodiment of the present utility model, the heat pump throttling device is a throttling valve.

[0014] According to one embodiment of the utility model, the energy storage cycle device also includes a precooler, and the low-pressure supercritical carbon dioxide storage tank is connected to the first compressor through the precooler.

[0015] According to one embodiment of the utility model, the energy storage circulation device also includes a water cooler, and the turbine expander is connected to the low-pressure supercritical carbon dioxide storage tank through the water cooler.

[0016] The characteristics and advantages of the heat pump supercritical carbon dioxide energy storage system of the utility model are:

[0017] By optimizing the design of the energy storage cycle device and the energy storage device, the system can increase the energy storage density of carbon dioxide, thereby reducing the required floor space. Specifically, the system uses supercritical carbon dioxide as the working medium, and through the coordinated work of the low-pressure supercritical carbon dioxide storage tank, the first compressor, the stage aftercooler, the high-pressure supercritical carbon dioxide storage tank and the turbine expander, an efficient energy storage and release process is achieved. In addition, the introduction of the energy storage device, which is used to store the compression heat released by the stage aftercooler, further improves the energy utilization efficiency of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0019] Figure 1 It is a schematic diagram of an implementation of a heat pump supercritical carbon dioxide energy storage system of the utility model;

[0020] Figure 2 It is a schematic diagram of another embodiment of a heat pump supercritical carbon dioxide energy storage system of the utility model.

[0021] Reference numerals:

[0022] 100. Energy storage circulation device; 110. Low-pressure supercritical carbon dioxide storage tank; 120. First compressor; 130. Aftercooler; 140. High-pressure supercritical carbon dioxide storage tank; 150. Turbine expander; 160. Precooler; 170. Water cooler; 200. Energy storage device; 210. Heat pump preheater; 220. High-temperature heat storage tank; 230. Heat pump evaporator; 240. Low-temperature heat storage tank; 300. Heat pump circulation device; 310. Heat pump reheater; 320. Heat pump throttling device; 330. Second compressor. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical solution and advantages of the utility model clearer, the technical solution of the utility model will be described clearly and completely in conjunction with the drawings in the utility model. Obviously, the described embodiments are part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0024] In the description of the present embodiment, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present embodiment and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present embodiment.

[0025] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of this embodiment, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0026] In this embodiment, unless otherwise clearly specified and limited, the terms "set", "install", "connect", "connect", "fix" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For those of ordinary skill in the art, the specific meanings of the above terms in this embodiment can be understood according to specific circumstances.

[0027] In the embodiments of the present invention, unless otherwise clearly specified and limited, the first feature being "above" or "below" the second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature being "above", "above" and "above" the second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. The first feature being "below", "below" and "below" the second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0028] Figure 1 to Figure 2 A heat pump supercritical carbon dioxide energy storage system provided by the utility model is shown. As can be seen from the figure, the utility model provides a heat pump supercritical carbon dioxide energy storage system, including an energy storage cycle device 100 and an energy storage device 200; the energy storage cycle device 100 includes a low-pressure supercritical carbon dioxide storage tank 110, a first compressor 120, a stage aftercooler 130, a high-pressure supercritical carbon dioxide storage tank 140 and a turbine expander 150 which are sequentially connected to form a closed loop; the energy storage device 200 is connected to the stage aftercooler 130, and is used to store the compression heat released by the stage aftercooler 130.

[0029] By optimizing the design of the energy storage cycle device 100 and the energy storage device 200, the system can increase the energy storage density of carbon dioxide, thereby reducing the required floor space. Specifically, the system uses supercritical carbon dioxide as the working medium, and realizes an efficient energy storage and release process through the coordinated work of the low-pressure supercritical carbon dioxide storage tank 110, the first compressor 120, the stage aftercooler 130, the high-pressure supercritical carbon dioxide storage tank 140 and the turbine expander 150. In addition, the introduction of the energy storage device 200, which is used to store the compression heat released by the stage aftercooler 130, further improves the energy utilization efficiency of the system.

[0030] like Figure 1As shown, in a feasible embodiment, the aftercooler 130 has a first heat exchange channel; the energy storage device 200 includes a heat pump preheater 210, a high-temperature heat storage tank 220, a heat pump evaporator 230 and a low-temperature heat storage tank 240; the inlet of the heat pump preheater 210 is connected to the outlet of the high-pressure supercritical carbon dioxide storage tank 140, and the outlet of the heat pump preheater 210 is connected to the inlet of the turbine expander 150, and the heat pump preheater 210 has a second heat exchange channel; the inlet of the high-temperature heat storage tank 220 is connected to the outlet of the first heat exchange channel, and the outlet of the high-temperature heat storage tank 220 is connected to the inlet of the second heat exchange channel; and also includes a heat pump circulation device 300; the heat pump evaporator 230 is connected to the heat pump circulation device 300, and the heat pump evaporator 230 has a third heat exchange channel, and the inlet of the third heat exchange channel is connected to the first heat exchange channel. The outlet of the second heat exchange channel and the outlet of the third heat exchange channel are connected to the inlet of the low-temperature heat storage tank 240; the outlet of the low-temperature heat storage tank 240 is connected to the inlet of the first heat exchange channel; the heat pump circulation device 300 includes a heat pump reheater 310, a heat pump throttling device 320 and a second compressor 330; the inlet of the heat pump reheater 310 is connected to the outlet of the heat pump preheater 210, the outlet of the heat pump reheater 310 is connected to the inlet of the turbine expander 150, and the heat pump reheater 310 has a third heat exchange channel; the inlet of the third heat exchange channel is connected to the outlet of the second compressor 330, and the outlet of the third heat exchange channel is connected to the inlet of the heat pump throttling device 320; the outlet of the heat pump throttling device 320 is connected to the inlet of the heat pump evaporator 230; the inlet of the second compressor 330 is connected to the outlet of the heat pump evaporator 230.

[0031] In specific implementation, this heat pump supercritical carbon dioxide energy storage system significantly improves the overall energy storage efficiency and heat recovery rate of the system through sophisticated thermal energy management and cycle design. Specifically, the system includes the following core features and workflows:

[0032] Thermal energy circulation and management: The system is designed with a highly integrated thermal energy circulation path, in which the after-stage cooler 130 collects the heat energy in the compression process through the first heat exchange channel and transfers it to the energy storage device 200. The high-temperature heat storage tank 220 and the low-temperature heat storage tank 240 in the energy storage device 200 work together, the former stores the compression heat energy, and the latter uses this part of the heat energy to preheat the heat pump cycle, realizing efficient storage and reuse of heat energy.

[0033] Heat pump preheating and energy boost: The heat pump preheater 210 is not only used as a condenser for the heat pump cycle, but also undertakes the task of further preheating the high-pressure supercritical carbon dioxide gas, thereby increasing the temperature of the gas entering the turbo expander 150, thereby improving the power generation efficiency of the turbo expander 150. In this process, the heat pump preheater 210 is connected to the thermal energy storage system through the second heat exchange channel, ensuring the effective flow and conversion of thermal energy.

[0034] Optimized configuration of heat pump cycle: The system also includes a heat pump cycle device 300, which is composed of a heat pump reheater 310, a heat pump throttling device 320 and a second compressor 330. The heat pump reheater 310 is connected to the second compressor 330 and the heat pump throttling device 320 through the third heat exchange channel to form a closed heat pump cycle, further optimizing the thermodynamic performance of the entire system. The second compressor 330 compresses the working fluid in the heat pump cycle, while the heat pump throttling device 320 adjusts the pressure and flow of the working fluid, ensuring the efficient operation of the heat pump system.

[0035] Energy recovery and recycling: The heat pump evaporator 230 is connected to the high-temperature heat storage tank 220 and the low-temperature heat storage tank 240 through the third heat exchange channel. It is not only used as an evaporator of the heat pump cycle, but also can cool the heat storage medium after heat release in the heat storage and exchange cycle, ensuring that the waste heat is recovered to the maximum extent and re-injected into the system, reducing energy loss.

[0036] In summary, through highly integrated thermal energy management and optimized heat pump cycle design, the system not only solves the problems of large footprint and low heat recovery efficiency of traditional heat pump supercritical carbon dioxide energy storage systems, but also significantly improves the overall cycle efficiency and energy density of the system, demonstrating excellent energy conservation, emission reduction and economic benefits.

[0037] like Figure 2As shown, in another feasible embodiment, the aftercooler 130 has a first heat exchange channel; the energy storage device 200 includes a heat pump preheater 210, a high-temperature heat storage tank 220, a heat pump evaporator 230 and a low-temperature heat storage tank 240; a heat pump supercritical carbon dioxide energy storage system also includes a heat pump circulation device 300; the inlet of the heat pump preheater 210 is connected to the outlet of the high-pressure supercritical carbon dioxide storage tank 140, the outlet of the heat pump preheater 210 is connected to the inlet of the turbine expander 150, and the heat pump preheater 210 has a second heat exchange channel; the inlet of the high-temperature heat storage tank 220 is connected to the outlet of the first heat exchange channel, and the outlet of the high-temperature heat storage tank 220 is connected to the heat pump circulation device 300; the inlet of the heat pump evaporator 230 is connected to the heat pump circulation device 300, the outlet of the heat pump evaporator 230 is connected to the inlet of the low-temperature heat storage tank 240, and the heat pump evaporator 230 has a third heat exchange channel, and the inlet of the third heat exchange channel is connected to the second heat exchange channel The outlet of the third heat exchange channel is connected to the heat pump circulation device 300; the outlet of the low-temperature heat storage tank 240 is connected to the inlet of the first heat exchange channel; the heat pump circulation device 300 includes a heat pump reheater 310, a heat pump throttling device 320 and a second compressor 330; the inlet of the heat pump reheater 310 is connected to the outlet of the heat pump preheater 210, the outlet of the heat pump reheater 310 is connected to the inlet of the turbine expander 150, and the heat pump reheater 310 has a third heat exchange channel; the inlet of the third heat exchange channel is connected to the outlet of the high-temperature heat storage tank 220, and the outlet of the third heat exchange channel is connected to the inlet of the heat pump evaporator 230; the inlet of the heat pump throttling device 320 is connected to the outlet of the second heat exchange channel, and the outlet of the heat pump throttling device 320 is connected to the inlet of the third heat exchange channel; the inlet of the second compressor 330 is connected to the outlet of the third heat exchange channel, and the outlet of the second compressor 330 is connected to the inlet of the second heat exchange channel; the heat pump throttling device 320 is a throttle valve.

[0038] In specific implementation, the after-stage cooler 130 and the first heat exchange channel: The after-stage cooler 130 in the system is designed with a first heat exchange channel, which is used to cool the supercritical carbon dioxide after the compression process, and at the same time recover and transmit this part of the compressed heat energy to the energy storage device 200. The composition of the energy storage device 200: The energy storage device 200 is composed of a heat pump preheater 210, a high-temperature heat storage tank 220, a heat pump evaporator 230 and a low-temperature heat storage tank 240, forming a complex heat energy storage and reuse network. Heat pump preheater 210 and heat energy circulation: The heat pump preheater 210 is located between the high-pressure supercritical carbon dioxide storage tank 140 and the turbine expander 150, and is connected through the second heat exchange channel. It not only preheats the carbon dioxide entering the turbine expander 150, but also works with the heat pump circulation device 300 to optimize the distribution of heat energy. Link between high-temperature heat storage tank 220 and heat pump cycle: The inlet and outlet ends of high-temperature heat storage tank 220 are respectively connected to the outlet of the first heat exchange channel and heat pump circulation device 300, realizing the gradient storage and redistribution of heat energy. Heat pump evaporator 230 and low-temperature heat storage tank 240: The heat pump evaporator 230 is interconnected with the second heat exchange channel and low-temperature heat storage tank 240 through the third heat exchange channel, which is not only used as part of the heat pump cycle, but also effectively utilizes the waste heat in the heat exchange process. Details of heat pump circulation device 300: The device includes a heat pump reheater 310, a heat pump throttling device 320 and a second compressor 330, wherein the heat pump reheater 310 is connected to the high-temperature heat storage tank 220 and the heat pump evaporator 230 through the third heat exchange channel, which enhances the recycling efficiency of heat energy. The heat pump throttling device 320 is used as a regulating tool to control the flow and pressure of the heat pump circulation working fluid to ensure efficient operation of the system. Function of heat pump throttling device 320: The throttling valve serves as the heat pump throttling device 320, and accurately controls the transition of the working fluid from high pressure to low pressure state, ensuring the stability and efficiency of the heat pump cycle.

[0039] In summary, through the above structural setting, this heat pump supercritical carbon dioxide energy storage system not only achieves efficient thermal energy management and improves the cycle efficiency of energy storage and release, but also solves the problem of low-grade thermal energy being difficult to recover, demonstrating its innovation and progress in the field of physical energy storage. Through the close cooperation between the heat pump circulation device 300 and the energy storage device 200, the system ensures efficient circulation and reuse of thermal energy within the system, reduces energy loss, and enhances the overall performance and environmental adaptability of the system.

[0040] It is understandable that the main difference between the above two embodiments is the difference in the maximum temperature of the heat pump cycle and the maximum temperature of the heat storage and release cycle. If the compression ratio of the first compressor 120 is large, the temperature of the carbon dioxide after compression will be large, while the compression ratio of the second compressor 330 is small, resulting in a low condensation temperature. The second embodiment can be adopted, and the carbon dioxide will be heated up in turn. If the opposite is true, the first embodiment is adopted.

[0041] According to one embodiment of the present utility model, the energy storage cycle device 100 further includes a precooler 160 , and the low-pressure supercritical carbon dioxide storage tank 110 is connected to the first compressor 120 via the precooler 160 .

[0042] In specific implementation, by arranging a precooler 160 between the low-pressure supercritical carbon dioxide storage tank 110 and the first compressor 120, the carbon dioxide gas about to enter the compressor is pretreated to ensure that it reaches a suitable inlet temperature before compression.

[0043] According to one embodiment of the present utility model, the energy storage cycle device 100 further includes a water cooler 170 , and the turbine expander 150 is connected to the low-pressure supercritical carbon dioxide storage tank 110 via the water cooler 170 .

[0044] In specific implementation, the role of the water cooler 170 is to adjust the temperature of the supercritical carbon dioxide output by the turbine expander 150. After the supercritical carbon dioxide expands and does work in the turbine expander 150, its temperature and pressure will drop, but may still be higher than the ambient temperature or the recharge temperature designed for the system. Through the water cooler 170, this part of the waste heat can be effectively removed to ensure that the temperature of the carbon dioxide returned to the low-pressure supercritical carbon dioxide storage tank 110 is appropriate, ready for the next round of energy storage; the effective removal of waste heat can not only avoid adverse effects on other parts of the system, but also improve the efficiency of the entire energy storage cycle. This is because the direct return of superheated carbon dioxide to the storage tank may cause the temperature of the storage tank to rise, requiring additional energy to cool, and the use of the water cooler 170 is directly processed after the turbine expander 150, reducing unnecessary energy losses and making the system cycle more efficient.

[0045] In this embodiment, the low-pressure supercritical carbon dioxide storage tank 110 and the high-pressure supercritical carbon dioxide storage tank 140 can be horizontal or vertical pressure vessels or spherical tanks, and insulation materials and heat-insulating shells can be provided on the outside for packaging. The heat storage medium in the heat storage and release cycle can be water, heat transfer oil and other low-melting-point liquid materials; the high-pressure supercritical carbon dioxide storage tank 140 can be a steel storage tank for storing compressed supercritical carbon dioxide. The aftercooler 130 is used to cool the compressed carbon dioxide to near room temperature for storage, and at the same time store the heat generated by compression in the heat storage medium. During heat exchange, the heat storage medium flows from the low-pressure supercritical carbon dioxide storage tank 110 to the high-pressure supercritical carbon dioxide storage tank 140 as a cold source. The heat pump reheater 310 is used to further heat the supercritical carbon dioxide before expansion, and during heat exchange, the heat storage medium flows from the high-pressure supercritical carbon dioxide storage tank 140 to the low-pressure supercritical carbon dioxide storage tank 110 as a heat source. Due to the existence of the heat exchange temperature difference, the heat storage medium flowing out of the heat pump reheater 310 still has some residual heat, so it enters the heat pump evaporator 230 as a heat source on the hot side to drive the heat pump cycle. The cooled heat storage medium returns to the low-pressure supercritical carbon dioxide storage tank 110. The heat pump evaporator 230 is used not only as an evaporator of the heat pump cycle, but also can cool the heat storage medium after heat release in the heat storage cycle to reuse the residual heat. The second compressor 330 is used to compress the heat pump cycle medium to the condensing pressure. The condensing pressure is affected by the condensing temperature required for heat exchange. The second compressor 330 can be piston type, screw type or centrifugal type. The heat pump preheater 210 is used not only as a condenser of the heat pump cycle, but also can heat up and preheat the carbon dioxide flowing out of the high-pressure supercritical carbon dioxide storage tank 140.

[0046] Working principle:

[0047] (I) Overview of energy storage process:

[0048] The system first cools the carbon dioxide stored in the low-pressure supercritical carbon dioxide storage tank 110, adjusts it to a suitable temperature through the precooler 160, and then uses electric energy to drive the first compressor 120 to compress the carbon dioxide to a high-pressure state. The heat energy generated at this time is transferred to the heat storage medium. Subsequently, the compressed carbon dioxide is cooled to near room temperature in the after-stage cooler 130 and stored in the high-pressure supercritical carbon dioxide storage tank 140 with a higher density. This series of operations essentially converts the input electrical energy into heat energy and the pressure potential energy of carbon dioxide for storage.

[0049] (II) Overview of energy release process:

[0050] When releasing energy, the carbon dioxide in the high-pressure supercritical carbon dioxide storage tank 140 first absorbs the high-temperature heat energy provided by the heat pump through the heat pump preheater 210 for preliminary heating. Subsequently, the heated carbon dioxide enters the heat pump reheater 310, where it further absorbs the high-temperature heat accumulated in the heat storage and release cycle to reach the set working temperature. After that, the fully preheated carbon dioxide enters the turbine expander 150, which drives the impeller to rotate during the expansion process, converts mechanical energy into electrical energy, and outputs it through the generator. If the temperature of the carbon dioxide after expansion is still higher than the ambient temperature, it will be cooled by the water cooler 170 to ensure that it returns to the low-pressure supercritical carbon dioxide storage tank 110 at an appropriate temperature to prepare for the next energy storage cycle. The entire energy release process effectively utilizes the previously stored thermal energy and realizes the efficient regeneration of electrical energy.

[0051] In summary, the utility model has at least the following characteristics and advantages:

[0052] 1. High energy density characteristics: This technology ensures that the system operates stably in the supercritical region with an operating pressure of more than 7.3 MPa and a temperature of more than 31 degrees Celsius. This characteristic gives the system extremely high energy density. Compared with air, supercritical carbon dioxide can store more energy in a smaller volume, improving energy storage efficiency.

[0053] 2. High-efficiency circulation system: Compared with the traditional compressed air energy storage system, the supercritical heat pump supercritical carbon dioxide energy storage system has a better circulation efficiency, which means that the loss is reduced during the energy conversion process, thereby improving the overall energy utilization efficiency.

[0054] 3. Compact system structure: Thanks to the high energy density and excellent thermodynamic properties of supercritical carbon dioxide, the system design can be more compact, which not only reduces the floor space but also effectively controls the construction cost of infrastructure.

[0055] 4. High-efficiency recovery of heat energy and system integration optimization: This utility model greatly enhances the recovery and utilization of low- and medium-grade compression heat by integrating supercritical carbon dioxide energy storage and heat pump technology, and improves the overall efficiency of the system. This design cleverly solves the problem of low-grade heat being difficult to recover in a traditional heat pump supercritical carbon dioxide energy storage system, while eliminating the reliance on external heat sources and ensuring the inlet temperature required for the operation of the turbine expander 150.

[0056] 5. Wide adaptability and deployment flexibility: The system is designed to be highly environmentally adaptable and is not restricted to specific geographical conditions. It can be easily deployed in deserts, plateaus or other areas rich in renewable energy, demonstrating its strong potential in diversified application scenarios.

[0057] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "mode", "specific mode", or "some modes" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or mode are included in at least one embodiment or mode of the utility model embodiment. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or mode. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or modes in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or modes described in this specification and the features of the different embodiments or modes, without contradiction.

[0058] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the utility model, rather than to limit it. Although the utility model has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the utility model.

Claims

1. A heat pump supercritical carbon dioxide energy storage system, characterized in that: It comprises an energy storage circulation device (100) and an energy storage device (200); The energy storage cycle device (100) comprises a low-pressure supercritical carbon dioxide storage tank (110), a first compressor (120), a stage aftercooler (130), a high-pressure supercritical carbon dioxide storage tank (140) and a turbine expander (150) which are connected in sequence to form a closed loop; The energy storage device (200) is connected to the after-stage cooler (130) and is used to store compression heat released by the after-stage cooler (130).

2. A heat pump supercritical carbon dioxide energy storage system according to claim 1, characterized in that: The after-stage cooler (130) has a first heat exchange passage; The energy storage device (200) comprises a heat pump preheater (210), a high-temperature heat storage tank (220), a heat pump evaporator (230) and a low-temperature heat storage tank (240); The inlet of the heat pump preheater (210) is connected to the outlet of the high-pressure supercritical carbon dioxide storage tank (140), the outlet of the heat pump preheater (210) is connected to the inlet of the turbine expander (150), and the heat pump preheater (210) has a second heat exchange channel; The inlet of the high-temperature heat storage tank (220) is connected to the outlet of the first heat exchange channel, and the outlet of the high-temperature heat storage tank (220) is connected to the inlet of the second heat exchange channel.

3. A heat pump supercritical carbon dioxide energy storage system according to claim 2, characterized in that: Also included is a heat pump circulation device (300); The heat pump evaporator (230) is connected to the heat pump circulation device (300), and the heat pump evaporator (230) has a third heat exchange channel, the inlet of the third heat exchange channel is connected to the outlet of the second heat exchange channel, and the outlet of the third heat exchange channel is connected to the inlet of the low-temperature heat storage tank (240); The outlet of the low-temperature heat storage tank (240) is connected to the inlet of the first heat exchange channel.

4. A heat pump supercritical carbon dioxide energy storage system according to claim 3, characterized in that: The heat pump circulation device (300) comprises a heat pump reheater (310), a heat pump throttling device (320) and a second compressor (330); The inlet of the heat pump reheater (310) is connected to the outlet of the heat pump preheater (210), the outlet of the heat pump reheater (310) is connected to the inlet of the turbine expander (150), and the heat pump reheater (310) has a third heat exchange channel; The inlet of the third heat exchange channel is connected to the outlet of the second compressor (330), and the outlet of the third heat exchange channel is connected to the inlet of the heat pump throttling device (320); The outlet of the heat pump throttling device (320) is connected to the inlet of the heat pump evaporator (230); The inlet of the second compressor (330) is connected to the outlet of the heat pump evaporator (230).

5. A heat pump supercritical carbon dioxide energy storage system according to claim 1, characterized in that: The after-stage cooler (130) has a first heat exchange passage; The energy storage device (200) comprises a heat pump preheater (210), a high-temperature heat storage tank (220), a heat pump evaporator (230) and a low-temperature heat storage tank (240); The heat pump supercritical carbon dioxide energy storage system further comprises a heat pump circulation device (300); The inlet of the heat pump preheater (210) is connected to the outlet of the high-pressure supercritical carbon dioxide storage tank (140), the outlet of the heat pump preheater (210) is connected to the inlet of the turbine expander (150), and the heat pump preheater (210) has a second heat exchange channel; The inlet of the high-temperature heat storage tank (220) is connected to the outlet of the first heat exchange channel, and the outlet of the high-temperature heat storage tank (220) is connected to the heat pump circulation device (300).

6. A heat pump supercritical carbon dioxide energy storage system according to claim 5, characterized in that: The inlet of the heat pump evaporator (230) is connected to the heat pump circulation device (300), the outlet of the heat pump evaporator (230) is connected to the inlet of the low-temperature heat storage tank (240), the heat pump evaporator (230) has a third heat exchange channel, the inlet of the third heat exchange channel is connected to the outlet of the second heat exchange channel, and the outlet of the third heat exchange channel is connected to the heat pump circulation device (300); The outlet of the low-temperature heat storage tank (240) is connected to the inlet of the first heat exchange channel.

7. A heat pump supercritical carbon dioxide energy storage system according to claim 6, characterized in that: The heat pump circulation device (300) comprises a heat pump reheater (310), a heat pump throttling device (320) and a second compressor (330); The inlet of the heat pump reheater (310) is connected to the outlet of the heat pump preheater (210), the outlet of the heat pump reheater (310) is connected to the inlet of the turbine expander (150), and the heat pump reheater (310) has a third heat exchange channel; The inlet of the third heat exchange channel is connected to the outlet of the high-temperature heat storage tank (220), and the outlet of the third heat exchange channel is connected to the inlet of the heat pump evaporator (230); The inlet of the heat pump throttling device (320) is connected to the outlet of the second heat exchange channel, and the outlet of the heat pump throttling device (320) is connected to the inlet of the third heat exchange channel; The inlet of the second compressor (330) is connected to the outlet of the third heat exchange channel, and the outlet of the second compressor (330) is connected to the inlet of the second heat exchange channel.

8. A heat pump supercritical carbon dioxide energy storage system according to claim 7, characterized in that: The heat pump throttling device (320) is a throttling valve.

9. A heat pump supercritical carbon dioxide energy storage system according to any one of claims 1 to 8, characterized in that: The energy storage cycle device (100) further comprises a precooler (160), and the low-pressure supercritical carbon dioxide storage tank (110) is connected to the first compressor (120) via the precooler (160).

10. A heat pump supercritical carbon dioxide energy storage system according to claim 9, characterized in that: The energy storage cycle device (100) further comprises a water cooler (170), and the turbine expander (150) is connected to the low-pressure supercritical carbon dioxide storage tank (110) via the water cooler (170).

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