Energy storage system

Abstract

The invention provides an energy storage system. The energy storage system comprises a low-pressure tank; the compressor unit communicates with the low-pressure tank through a first communicating pipeline; the high-pressure tank is communicated with the compressor unit through a second communicating pipeline; the expansion unit communicates with the high-pressure tank through a third communicating pipeline, and the expansion unit communicates with the low-pressure tank through a fourth communicating pipeline; the solar heating assembly is communicated with an inlet of the expansion unit; wherein the solar heating assembly comprises a solar heater, a heat conduction oil tank and a solar heat collector, the solar heater and the solar heat collector are both communicated with the heat conduction oil tank, and the solar heater is arranged on the third communication pipeline and communicated with an inlet of the expansion unit. According to the technical scheme, the problem that the output efficiency of the energy storage system is low due to the fact that the temperature of air in the expansion machine in the expansion process in the prior art is obviously reduced is effectively solved.

Description

Technical Field

[0001] The present invention relates to the technical field of power storage, and in particular to an energy storage system. Background Art

[0002] Energy storage technology can store electricity during the low-consumption period and release it during the peak-consumption period, achieving the effect of shifting peaks and filling valleys. Energy storage technology plays a vital role in peak regulation of the power grid.

[0003] In the related art, a compressor is used to compress air during the low electricity consumption period to store the electric energy, and an expander is used to expand the compressed air during the peak electricity consumption period to generate power to be transmitted to the generator to release the electric energy.

[0004] However, since the temperature of the air in the expander in the related technology will drop significantly during the expansion process, the thermodynamic efficiency of the expansion process will be reduced, resulting in a low output efficiency of the energy storage system. Summary of the invention

[0005] The main purpose of the present invention is to provide an energy storage system to solve the problem in the related art that the temperature of the air in the expander drops significantly during the expansion process, resulting in low output efficiency of the energy storage system.

[0006] In order to achieve the above-mentioned purpose, the present invention provides an energy storage system, including: a low-pressure tank; a compressor unit, connected to the low-pressure tank through a first connecting pipeline; a high-pressure tank, connected to the compressor unit through a second connecting pipeline; an expansion unit, connected to the high-pressure tank through a third connecting pipeline, and the expansion unit is connected to the low-pressure tank through a fourth connecting pipeline; a solar heating component, connected to the inlet of the expansion unit; wherein the solar heating component includes a solar heater, a thermal oil tank and a solar collector, the solar heater and the solar collector are both connected to the thermal oil tank, and the solar heater is arranged on the third connecting pipeline and connected to the inlet of the expansion unit.

[0007] Furthermore, the energy storage system also includes a hot water tank, a low-temperature tank, an intercooler group arranged on the second connecting pipeline, and a reheater group arranged on the third connecting pipeline, the water outlet of the intercooler group is connected to the water inlet of the hot water tank, the water outlet of the hot water tank is connected to the water inlet of the reheater group, the water outlet of the reheater group is connected to the water inlet of the low-temperature tank, and the water outlet of the low-temperature tank is connected to the water inlet of the intercooler group; an intercooler pipe is provided between the water outlet of the intercooler group and the water inlet of the intercooler group, and a reheat pipe is provided between the water outlet of the reheater group and the water inlet of the reheater group.

[0008] Furthermore, the expansion unit includes a first expander, a second expander and a third expander which are arranged in series in sequence, the reheater group includes a first reheater arranged upstream of the first expander, a second reheater arranged between the first expander and the second expander, and a third reheater arranged between the second expander and the third expander, the first reheater, the second reheater and the third reheater are arranged in parallel, the solar heater is located upstream of the first expander, and the first reheater is located between the high-pressure tank and the solar heater; the water outlet of the second reheater is connected to the water inlet of the low-temperature tank through a fifth connecting pipeline, and the energy storage system also includes an evaporator, a fourth expander, a condenser and a waste heat recovery compressor which are connected in sequence, the waste heat recovery compressor is connected to the evaporator, and the evaporator is arranged on the fifth connecting pipeline.

[0009] Furthermore, the energy storage system also includes a regenerator, which includes a first pipeline and a second pipeline. The first pipeline is connected between the first reheater and the solar heater, and the second pipeline is connected between the first expander and the second reheater.

[0010] Furthermore, the energy storage system also includes a first radiator located between the third expander and the low-pressure tank.

[0011] Furthermore, the energy storage system also includes a second radiator, which is located downstream of the evaporator. The water inlet of the second radiator is connected to the water outlet of the first reheater, the water outlet of the second reheater and the water outlet of the third reheater, and the water outlet of the second radiator is connected to the water inlet of the low-temperature tank.

[0012] Furthermore, the compressor unit includes a first compressor, a second compressor and a third compressor which are arranged in series in sequence, the intercooler group includes a first intercooler arranged between the first compressor and the second compressor, a second intercooler arranged between the second compressor and the third compressor, and a third intercooler arranged downstream of the third compressor, and the first intercooler, the second intercooler and the third intercooler are arranged in parallel.

[0013] Furthermore, the energy storage system also includes a first stop valve arranged between the low-pressure tank and the first compressor.

[0014] Furthermore, the solar heating assembly also includes a first thermal oil pump disposed between the solar heater and the inlet of the thermal oil tank and a second thermal oil pump disposed between the solar collector and the inlet of the thermal oil tank.

[0015] Furthermore, the energy storage system also includes a second stop valve arranged between the high-pressure tank and the first reheater.

[0016] Applying the technical solution of the present invention, the energy storage system includes: a low-pressure tank, a compressor unit, a high-pressure tank, an expansion unit and a solar heating component. The compressor unit is connected to the low-pressure tank through a first connecting pipeline. The high-pressure tank is connected to the compressor unit through a second connecting pipeline. The expansion unit is connected to the high-pressure tank through a third connecting pipeline, and the expansion unit is connected to the low-pressure tank through a fourth connecting pipeline. The solar heating component is connected to the inlet of the expansion unit. In this way, during the low-power consumption period, the compressor unit can be used to compress the air to store the electric energy. During the peak power consumption period, the expansion unit is used to expand the compressed air to generate power to be transmitted to the generator to release the electric energy. The setting of the solar heating component can heat the air at the inlet of the expansion unit, so that the temperature of the air just entering the expansion unit is increased, thereby reducing the temperature of the air dropping to a low temperature during the expansion process, reducing the heat energy converted into low-temperature waste heat during the expansion process, increasing the mechanical energy and output work output by the expansion unit, and improving the thermodynamic efficiency during the expansion process, thereby improving the output efficiency of the energy storage system. Therefore, the technical solution of the present application effectively solves the problem in the related art that the temperature of the air in the expander drops significantly during the expansion process, resulting in low output efficiency of the energy storage system. Among them, the solar heating component includes a solar heater, a thermal oil tank and a solar collector. The solar heater and the solar collector are both connected to the thermal oil tank, and the solar heater is arranged on the third connecting pipeline and connected to the inlet of the expansion unit. The arrangement of the solar heater, the thermal oil tank and the solar collector can effectively heat the air at the inlet of the expansion unit, reduce the temperature drop during the expansion process, thereby reducing the proportion of heat energy converted into low-temperature waste heat, increasing the mechanical energy and output work output by the expander, and improving the thermodynamic efficiency. This not only increases the output efficiency of the energy release stage, but also makes full use of renewable energy and reduces dependence on fossil fuels. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The drawings constituting a part of the present application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0018] Figure 1 A connection diagram of an embodiment of an energy storage system according to the present invention is shown.

[0019] The above drawings include the following reference numerals:

[0020] 11. First connecting pipeline; 12. Second connecting pipeline; 13. Third connecting pipeline; 14. Fourth connecting pipeline; 15. Fifth connecting pipeline;

[0021] 21. Solar heater; 22. Thermal oil tank; 23. Solar collector; 24. Hot water tank; 25. Low temperature tank; 26. Low pressure tank; 27. High pressure tank;

[0022] 31. first expander; 32. second expander; 33. third expander;

[0023] 41. a first compressor; 42. a second compressor; 43. a third compressor;

[0024] 51. first reheater; 52. second reheater; 53. third reheater;

[0025] 61. The first intercooler; 62. The second intercooler; 63. The third intercooler;

[0026] 71. Evaporator; 72. Fourth expander; 73. Condenser; 74. Waste heat recovery compressor; 75. Regenerator;

[0027] 81. a first radiator; 82. a second radiator;

[0028] 91. First stop valve; 92. Second stop valve; 93. First thermal oil pump; 94. Second thermal oil pump. DETAILED DESCRIPTION

[0029] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0031] Unless otherwise specifically stated, the relative arrangement, numerical expressions and numerical values ​​of the parts and steps set forth in these embodiments do not limit the scope of the present invention. Meanwhile, it should be understood that, for ease of description, the sizes of the various parts shown in the accompanying drawings are not drawn according to the actual proportional relationship. The technology, method and equipment known to those of ordinary skill in the relevant art may not be discussed in detail, but in appropriate cases, the technology, method and equipment should be considered as a part of the specification. In all examples shown and discussed here, any specific value should be interpreted as being merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters represent similar items in the following drawings, and therefore, once a certain item is defined in an accompanying drawing, it does not need to be further discussed in subsequent drawings.

[0032] In this embodiment, if Figure 1 As shown, the energy storage system includes: a low-pressure tank 26, a compressor unit, a high-pressure tank 27, an expansion unit and a solar heating assembly. The compressor unit is connected to the low-pressure tank 26 through a first connecting line 11. The high-pressure tank 27 is connected to the compressor unit through a second connecting line 12. The expansion unit is connected to the high-pressure tank 27 through a third connecting line 13, and the expansion unit is connected to the low-pressure tank 26 through a fourth connecting line 14. The solar heating assembly is connected to the inlet of the expansion unit. Among them, the solar heating assembly includes a solar heater 21, a thermal oil tank 22 and a solar collector 23. The solar heater 21 and the solar collector 23 are both connected to the thermal oil tank 22, and the solar heater 21 is arranged on the third connecting line 13 and connected to the inlet of the expansion unit. The solar heater 21, the thermal oil tank 22 and the solar collector 23 can effectively heat the air at the inlet of the expansion unit, reduce the temperature drop during the expansion process, thereby reducing the proportion of heat energy converted into low-temperature waste heat, increasing the mechanical energy and output work output by the expander, and improving the thermodynamic efficiency. This not only increases the output efficiency of the energy release stage, but also makes full use of renewable energy and reduces dependence on fossil fuels.

[0033] In this way, during the low electricity consumption period, the compressor unit can be used to compress the air to store the electric energy. During the peak electricity consumption period, the expansion unit is used to expand the compressed air to generate power to be transmitted to the generator to release the electric energy. The setting of the solar heating component can heat the air at the inlet of the expansion unit, so that the temperature of the air just entering the expansion unit is increased, thereby reducing the temperature drop of the air to a low temperature during the expansion process, reducing the heat energy converted into low-temperature waste heat during the expansion process, increasing the mechanical energy and output work output by the expansion unit, and improving the thermodynamic efficiency during the expansion process, thereby improving the output efficiency of the energy storage system. Therefore, the technical solution of the present application effectively solves the problem that the temperature of the air in the expander in the related art drops significantly during the expansion process, resulting in a low output efficiency of the energy storage system. Among them, the solar heating component includes a solar heater 21, a thermal oil tank 22 and a solar collector 23. The solar heater 21 and the solar collector 23 are both connected to the thermal oil tank 22, and the solar heater 21 is arranged on the third connecting pipeline 13 and connected to the inlet of the expansion unit. The solar heater 21, the thermal oil tank 22 and the solar collector 23 can effectively heat the air at the inlet of the expansion unit, reduce the temperature drop during the expansion process, thereby reducing the proportion of heat energy converted into low-temperature waste heat, increasing the mechanical energy and output work output by the expander, and improving the thermodynamic efficiency. This not only increases the output efficiency of the energy release stage, but also makes full use of renewable energy and reduces dependence on fossil fuels.

[0034] like Figure 1 As shown, the energy storage system also includes a hot water tank 24, a low temperature tank 25, an intercooler group arranged on the second connecting pipeline 12, and a reheater group arranged on the third connecting pipeline 13. The water outlet of the intercooler group is connected to the water inlet of the hot water tank 24, the water outlet of the hot water tank 24 is connected to the water inlet of the reheater group, the water outlet of the reheater group is connected to the water inlet of the low temperature tank 25, and the water outlet of the low temperature tank 25 is connected to the water inlet of the intercooler group. There is an intercooling pipeline between the water outlet of the intercooler group and the water inlet of the intercooler group, and there is a reheating pipeline between the water outlet of the reheater group and the water inlet of the reheater group. Through the circulation established by the hot water tank 24, the low temperature tank 25, the intercooler group and the reheater group, efficient storage and release of the heat storage medium are achieved. The hot water tank 24 stores high-temperature heat storage medium, and the low temperature tank 25 recovers low-temperature heat storage medium to form a closed cycle. This ensures the effective circulation of energy in the system, reduces energy loss, and improves the overall energy storage density. When the air pressure is constant, the setting of the intercooler group can reduce the temperature of the air entering the second connecting pipe 12, thereby reducing the temperature of the air entering the compressor unit, reducing the power consumption of the compression process of the compressor unit, and reducing the system input power while the system output power remains unchanged, thereby improving the system performance.

[0035] In this embodiment, the indirect cooling pipe and the second connecting pipe 12 can exchange heat, and are not connected. The reheat pipe and the third connecting pipe 13 can exchange heat, and are not connected.

[0036] like Figure 1 As shown, the expansion unit includes a first expansion machine 31, a second expansion machine 32 and a third expansion machine 33 which are sequentially arranged in series. The reheater group includes a first reheater 51 arranged upstream of the first expansion machine 31, a second reheater 52 arranged between the first expansion machine 31 and the second expansion machine 32, and a third reheater 53 arranged between the second expansion machine 32 and the third expansion machine 33. The first reheater 51, the second reheater 52 and the third reheater 53 are arranged in parallel, the solar heater 21 is located upstream of the first expansion machine 31, and the first reheater 51 is located between the high-pressure tank 27 and the solar heater 21. The water outlet of the second reheater 52 is connected to the water inlet of the low-temperature tank 25 through the fifth connecting pipeline 15, and the energy storage system also includes an evaporator 71, a fourth expansion machine 72, a condenser 73 and a waste heat recovery compressor 74 which are sequentially connected. The waste heat recovery compressor 74 is connected to the evaporator 71, and the evaporator 71 is arranged on the fifth connecting pipeline 15. The series use of the first expander 31, the second expander 32 and the third expander 33, and the parallel arrangement of the first compressor 41, the second compressor 42 and the third compressor 43 increase the system pressure range, thereby improving the energy storage density. Through multi-stage compression and expansion, the burden of single-stage equipment is reduced, and the efficiency and reliability of the entire system are improved. At the same time, through the first reheater 51, the second reheater 52 and the third reheater 53, the temperature of the air can be further increased, the temperature of the air at the inlet of the expansion unit can be increased, and the output power of the expansion unit can be increased.

[0037] In this embodiment, the arrangement of the evaporator 71, the fourth expander 72, the condenser 73 and the waste heat recovery compressor 74 can recover the waste heat in the heat storage medium output by the second reheater 52, and use it for power generation to increase the system output work, thereby further improving the performance of the energy storage system. The waste heat in the heat storage medium output by the second reheater 52 is relatively large, and the above arrangement reduces the waste of heat.

[0038] like Figure 1As shown, the energy storage system also includes a regenerator 75, which includes a first pipe and a second pipe. The first pipe is connected between the first reheater 51 and the solar heater 21, and the second pipe is connected between the first expander 31 and the second reheater 52. The arrangement of the regenerator 75 realizes the internal recovery of heat and reduces the dependence on external heat sources. This allows part of the heat of the high-temperature air at the outlet of the first expander 31 to be recovered by the heat storage medium, while additional heat is supplemented by the solar heater 21, and the heat is transferred to the air at the inlet of the expansion unit, further improving the output power of the expansion unit.

[0039] like Figure 1 As shown, the energy storage system further includes a first radiator 81 located between the third expander 33 and the low-pressure tank 26. The first radiator 81 located between the third expander 33 and the low-pressure tank 26 helps to release the remaining heat energy carried by the expanded air into the environment, reduces the temperature rise of the air in the circulation, prevents the accumulation of heat energy, and maintains the thermal balance of the system.

[0040] like Figure 1 As shown, the energy storage system further includes a second radiator 82, which is located downstream of the evaporator 71, and the water inlet of the second radiator 82 is connected to the water outlet of the first reheater 51, the water outlet of the second reheater 52, and the water outlet of the third reheater 53, and the water outlet of the second radiator 82 is connected to the water inlet of the low-temperature tank 25. The arrangement of the second radiator 82, especially downstream of the evaporator 71, can centrally recover the waste heat in the low-temperature medium released by the first reheater 51, the second reheater 52, and the third reheater 53, and release the heat energy to the environment.

[0041] like Figure 1 As shown, the compressor unit includes a first compressor 41, a second compressor 42 and a third compressor 43 which are sequentially arranged in series. The intercooler group includes a first intercooler 61 arranged between the first compressor 41 and the second compressor 42, a second intercooler 62 arranged between the second compressor 42 and the third compressor 43, and a third intercooler 63 arranged downstream of the third compressor 43. The first intercooler 61, the second intercooler 62 and the third intercooler 63 are arranged in parallel. The three-stage compression design of the compressor unit and the parallel configuration of the intercooler group effectively reduce the temperature rise of the air during the compression process, reduce the power consumption of the compressor unit, and thus improve the energy input efficiency of the energy storage stage. The intercooler group realizes the effective utilization of the high-temperature heat storage medium by connecting with the hot water tank 24, further reducing energy loss.

[0042] like Figure 1As shown, the energy storage system further includes a first stop valve 91 disposed between the low-pressure tank 26 and the first compressor 41. The use of the first stop valve 91 enables the flow of air to be accurately controlled at the beginning or end of the energy storage process, thereby reducing ineffective energy loss and ensuring smooth switching of the system between different operating modes.

[0043] like Figure 1 As shown, the solar heating assembly also includes a first thermal oil pump 93 disposed between the solar heater 21 and the inlet of the thermal oil tank 22, and a second thermal oil pump 94 disposed between the solar collector 23 and the inlet of the thermal oil tank 22. The addition of the first thermal oil pump 93 and the second thermal oil pump 94 improves the flow efficiency of the heat storage medium circulation, so that the heat collected by the solar collector 23 can be quickly and efficiently transferred to the solar heater 21, thereby heating the air at the inlet of the expansion unit, thereby improving the efficiency and speed of energy transfer.

[0044] like Figure 1 As shown, the energy storage system further includes a second stop valve 92 disposed between the high-pressure tank 27 and the first reheater 51. The second stop valve 92 is disposed between the high-pressure tank 27 and the first reheater 51, and can accurately control the flow rate and pressure of the air in the energy release stage, thereby optimizing the operating conditions of the expansion unit and improving the output efficiency and stability of the system in the energy release stage.

[0045] In this embodiment, by controlling the first stop valve 91 and the second stop valve 92, the energy storage system can realize the conversion between the nighttime energy storage phase and the daytime energy release phase, so that the system can realize efficient energy storage.

[0046] By applying the technical solution of this embodiment, during the energy release stage, the setting of the regenerator 75 can utilize the high temperature of the air at the outlet of the first expander 31 to increase the temperature of the air at the inlet of the first expander 31, thereby heating the air at the inlet of the expansion unit, thereby improving the efficiency and speed of energy transfer. At the same time, a solar heater 21 is added between the regenerator 75 and the first expander 31, and the high-temperature heat storage medium of the solar heating component is used to further heat the air temperature at the inlet of the first expander 31 to increase the output power of the first expander 31. Due to the addition of the solar heating component, the temperature of the heat storage medium entering the second reheater 52 is still high, and finally the heat storage medium at the outlet of the second reheater 52 still has a high waste heat. An ORC waste heat recovery subsystem is set at the outlet of the second reheater 52 to recover this part of the waste heat for power generation to increase the system output power and further improve the performance of the energy storage system. The ORC waste heat recovery subsystem includes an evaporator 71, a fourth expander 72, a condenser 73 and a waste heat recovery compressor 74 which are connected in sequence.

[0047] This embodiment uses three-stage compression and three-stage expansion to store energy. Compared with other energy storage systems, this embodiment has higher energy storage pressure, greater energy storage density, and greater energy storage capacity. Due to the coupling of solar heating components and ORC waste heat recovery system, the system output power is higher, energy waste is reduced, and the utilization rate of renewable energy is improved, achieving the purpose of energy saving and environmental protection, making full use of low-grade thermal energy in the system, and improving the thermodynamic performance of the energy storage system.

[0048] In the description of the present invention, it is necessary to understand that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "lateral, vertical, perpendicular, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the drawings. They are only for the convenience of describing the present invention and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the devices or elements referred to must have a specific direction or be constructed and operated in a specific direction. Therefore, they cannot be understood as limiting the scope of protection of the present invention. The directional words "inside and outside" refer to the inside and outside relative to the contours of each component itself.

[0049] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used here to describe the spatial positional relationship between a device or feature and other devices or features as shown in the figure. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figure. For example, if the device in the accompanying drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0050] In addition, it should be noted that the use of terms such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. If not otherwise stated, the above terms have no special meaning and therefore cannot be understood as limiting the scope of protection of the present invention.

[0051] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An energy storage system, characterized in that: include: Low pressure tank (26); A compressor unit is connected to the low-pressure tank (26) via a first connecting pipeline (11); A high-pressure tank (27) is connected to the compressor unit via a second connecting pipeline (12); an expansion unit connected to the high-pressure tank (27) via a third connecting pipeline (13), and the expansion unit connected to the low-pressure tank (26) via a fourth connecting pipeline (14); A solar heating assembly is connected to the inlet of the expansion unit; The solar heating assembly comprises a solar heater (21), a heat transfer oil tank (22) and a solar collector (23); the solar heater (21) and the solar collector (23) are both connected to the heat transfer oil tank (22); the solar heater (21) is arranged on the third connecting pipeline (13) and is connected to the inlet of the expansion unit.

2. The energy storage system according to claim 1, characterized in that: The energy storage system further comprises a hot water tank (24), a low temperature tank (25), an intercooler group arranged on the second connecting pipeline (12), and a reheater group arranged on the third connecting pipeline (13); the water outlet of the intercooler group is connected to the water inlet of the hot water tank (24); the water outlet of the hot water tank (24) is connected to the water inlet of the reheater group; the water outlet of the reheater group is connected to the water inlet of the low temperature tank (25); the water outlet of the low temperature tank (25) is connected to the water inlet of the intercooler group; an intercooler pipe is provided between the water outlet of the intercooler group and the water inlet of the intercooler group; and a reheat pipe is provided between the water outlet of the reheater group and the water inlet of the reheater group.

3. The energy storage system according to claim 2, characterized in that: The expansion machine group comprises a first expansion machine (31), a second expansion machine (32) and a third expansion machine (33) which are sequentially connected in series; the reheater group comprises a first reheater (51) arranged upstream of the first expansion machine (31), a second reheater (52) arranged between the first expansion machine (31) and the second expansion machine (32), and a third reheater (53) arranged between the second expansion machine (32) and the third expansion machine (33); the first reheater (51), the second reheater (52) and the third reheater (53) are arranged in parallel; the solar heater (21) is located upstream of the first expansion machine (31); and the first reheater (51) is located between the high-pressure tank (27) and the solar heater (21); The water outlet of the second reheater (52) is connected to the water inlet of the low-temperature tank (25) via a fifth connecting pipe (15). The energy storage system further comprises an evaporator (71), a fourth expander (72), a condenser (73) and a waste heat recovery compressor (74) which are connected in sequence. The waste heat recovery compressor (74) is connected to the evaporator (71), and the evaporator (71) is arranged on the fifth connecting pipe (15).

4. The energy storage system according to claim 3, characterized in that: The energy storage system further includes a regenerator (75), wherein the regenerator (75) includes a first pipeline and a second pipeline, wherein the first pipeline is connected between the first reheater (51) and the solar heater (21), and the second pipeline is connected between the first expander (31) and the second reheater (52).

5. The energy storage system according to claim 3, characterized in that: The energy storage system further comprises a first radiator (81) located between the third expander (33) and the low-pressure tank (26).

6. The energy storage system according to claim 3, characterized in that: The energy storage system further comprises a second radiator (82), the second radiator (82) being located downstream of the evaporator (71), the water inlet of the second radiator (82) being connected to the water outlet of the first reheater (51), the water outlet of the second reheater (52) and the water outlet of the third reheater (53), and the water outlet of the second radiator (82) being connected to the water inlet of the low-temperature tank (25).

7. The energy storage system according to claim 2, characterized in that: The compressor group comprises a first compressor (41), a second compressor (42) and a third compressor (43) which are sequentially arranged in series; the intercooler group comprises a first intercooler (61) arranged between the first compressor (41) and the second compressor (42), a second intercooler (62) arranged between the second compressor (42) and the third compressor (43), and a third intercooler (63) arranged downstream of the third compressor (43); the first intercooler (61), the second intercooler (62) and the third intercooler (63) are arranged in parallel.

8. The energy storage system according to claim 7, characterized in that: The energy storage system further comprises a first stop valve (91) arranged between the low-pressure tank (26) and the first compressor (41).

9. The energy storage system according to claim 1, characterized in that: The solar heating assembly further comprises a first thermal oil pump (93) arranged between the solar heater (21) and the inlet of the thermal oil tank (22), and a second thermal oil pump (94) arranged between the solar collector (23) and the inlet of the thermal oil tank (22).

10. The energy storage system according to claim 3, characterized in that: The energy storage system further includes a second stop valve (92) disposed between the high-pressure tank (27) and the first reheater (51).

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