Energy storage system of liquid compressed carbon dioxide cycle coupled with heat pump drying

Abstract

The present invention provides an energy storage system for liquid compressed carbon dioxide cycle coupled heat pump drying, comprising an energy storage unit, a closed cycle heat pump drying unit, an energy release unit, a heat storage unit and a photothermal auxiliary unit, wherein the energy storage unit comprises a throttle valve, a first compressor, a second compressor, a first cooler and a first liquid storage tank; the closed cycle heat pump drying unit comprises a dehumidifier, an air heater and a drying chamber; the energy release unit comprises a preheater, a regenerator, a first high temperature reheater, a first expander, a second high temperature reheater, a second expander, a second cooler, a cold storage unit and a second liquid storage tank; the heat storage unit comprises a first intercooler, a second intercooler, a first hot tank and a first cold tank; the photothermal auxiliary unit comprises a solar collector, a second hot tank and a second cold tank. The present invention can achieve efficient use of heat and high energy storage efficiency.

Description

Technical Field

[0001] The invention relates to the technical field of liquid compressed carbon dioxide energy storage, and in particular to an energy storage system of liquid compressed carbon dioxide cycle coupled with heat pump drying. Background Art

[0002] The principle of compressed air energy storage is to store compressed high-pressure air in natural caves to achieve electrical energy storage. The concept was first proposed by Stal Laval in 1949. Compared with air, carbon dioxide has excellent thermal properties, lower critical parameters, and excellent heat exchange performance, which all indicate that carbon dioxide can be used as a working fluid to replace air in compressed air energy storage. Liquid compressed carbon dioxide energy storage is a type of compressed carbon dioxide energy storage technology. Its principle is very similar to that of compressed carbon dioxide energy storage technology, but the liquid compressed carbon dioxide energy storage system uses liquid carbon dioxide for electrical energy storage, which has a higher energy storage density. Its working principle is: during the energy storage process, the liquid carbon dioxide in the liquid storage tank enters the throttle valve to cool down and reduce pressure, and then enters the cold storage device for gasification. Driven by the motor, the gaseous carbon dioxide enters the compressors and intercoolers at each stage for multi-stage compression and interstage cooling. The cooling water is used as a heat transfer medium to absorb heat and store it in the hot tank. The high-pressure carbon dioxide is then cooled into liquid by the cooler and stored in the liquid storage tank. During the energy release process, liquid high-pressure carbon dioxide enters each stage of reheaters and expanders for pre-stage reheating and multi-stage expansion. Hot water is stored in a cold tank after releasing heat as a heat transfer medium. The low-temperature and low-pressure carbon dioxide that has completed work enters the cold storage device for cooling and liquefaction and is stored in a liquid storage tank.

[0003] Liquid compressed carbon dioxide energy storage systems have received close attention from researchers at home and abroad. Although there are no large-scale commercial applications at present, there are some demonstration projects. In 2021, Energy Dome deployed a 2.5MW / 4MWh liquid compressed carbon dioxide energy storage system in Sardinia, Italy; Dongfang Electric Group Dongfang Turbine Co., Ltd. deployed a liquid compressed carbon dioxide energy storage + flywheel energy storage demonstration project in Deyang, Sichuan. However, since the high-pressure carbon dioxide is cooled to liquid by using the cold energy of the environment during the energy storage process, a large amount of condensation latent heat is wasted, and part of the compression heat in the energy release process is used for the latent heat of vaporization of liquid carbon dioxide. Therefore, it is easy for the compression heat to fail to meet the needs of the expander and the system energy storage efficiency is low. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides an energy storage system of liquid compressed carbon dioxide circulation coupled with heat pump drying, which can achieve efficient utilization of heat and has high energy storage efficiency.

[0005] The technical solution adopted by the present invention is as follows:

[0006] A liquid compressed carbon dioxide cycle coupled heat pump drying energy storage system, comprising an energy storage unit, a closed-cycle heat pump drying unit, an energy release unit, a heat storage unit and a photothermal auxiliary unit, wherein the energy storage unit comprises a throttle valve, a first compressor, a second compressor, a first cooler and a first liquid storage tank, the outlet of the first cooler is connected to the inlet of the first liquid storage tank; the closed-cycle heat pump drying unit comprises a dehumidifier, an air heater and a drying chamber, the first inlet of the dehumidifier is connected to the outlet of the drying chamber, the second inlet of the dehumidifier is connected to the outlet of the first liquid storage tank, the first outlet of the dehumidifier is connected to the first inlet of the air heater, and the inlet of the drying chamber is connected to the first inlet of the air heater. an outlet connected; the energy release unit includes a preheater, a regenerator, a first high-temperature reheater, a first expander, a second high-temperature reheater, a second expander, a second cooler, a cold storage tank and a second liquid storage tank, the first inlet of the preheater is connected to the second outlet of the dehumidifier, the first outlet of the preheater is connected to the first inlet of the regenerator, the first outlet of the regenerator is connected to the first inlet of the first high-temperature reheater, the first outlet of the first high-temperature reheater is connected to the inlet of the first expander, the outlet of the first expander is connected to the first inlet of the second high-temperature reheater, the first outlet of the second high-temperature reheater is connected to the inlet of the second expander, and the outlet of the second expander is connected to the regenerator. The second inlet of the regenerator is connected to the second inlet of the air heater, the second outlet of the regenerator is connected to the second inlet of the air heater, the inlet of the second cooler is connected to the second outlet of the air heater, the first inlet of the cold accumulator is connected to the outlet of the throttle valve, the first outlet of the cold accumulator is connected to the inlet of the first compressor, the second inlet of the cold accumulator is connected to the outlet of the second cooler, the second outlet of the cold accumulator is connected to the inlet of the second liquid storage tank, and the outlet of the second liquid storage tank is connected to the inlet of the throttle valve; the thermal storage unit includes a first intercooler, a second intercooler, a first hot tank and a first cold tank, the first inlet of the first intercooler is connected to the outlet of the first compressor, the first inlet of the first intercooler is connected to the outlet of the first compressor, the second inlet of the first intercooler is connected to the outlet of the second cooler, the second outlet of the cold accumulator is connected to the inlet of the second liquid storage tank, and the outlet of the second liquid storage tank is connected to the inlet of the throttle valve; an outlet connected to the inlet of the second compressor, a second inlet of the first intercooler connected to the outlet of the first cold tank, a second outlet of the first intercooler connected to the inlet of the first hot tank, a first inlet of the second intercooler connected to the outlet of the second compressor, a first outlet of the second intercooler connected to the inlet of the first cooler, a second inlet of the second intercooler connected to the outlet of the first cold tank, a second outlet of the second intercooler connected to the inlet of the first hot tank, an outlet of the first hot tank connected to the second inlet of the preheater, a second outlet of the preheater connected to the third inlet of the air heater, and an inlet of the first cold tank connected to the third outlet of the air heater;The photothermal auxiliary unit includes a solar collector, a second hot tank and a second cold tank, the inlet of the solar collector is connected to the outlet of the second cold tank, the outlet of the solar collector is connected to the inlet of the second hot tank, the outlet of the second hot tank is respectively connected to the second inlet of the first high-temperature reheater and the second inlet of the second high-temperature reheater, and the inlet of the second cold tank is respectively connected to the second outlet of the first high-temperature reheater and the second outlet of the second high-temperature reheater.;

[0007] The first compressor and the second compressor are also connected to an electric motor.

[0008] The first expander and the second expander are also connected to a generator.

[0009] The throttle valve is an expansion valve.

[0010] Beneficial effects of the present invention:

[0011] The present invention utilizes the liquid carbon dioxide in the liquid storage tank during the energy storage process to provide the cooling capacity required for condensation and dehumidification for the dehumidifier of the closed-cycle heat pump drying unit; utilizes the photothermal auxiliary unit to use the high-temperature solar energy storage medium that absorbs solar energy as the heat source for reheating before each level of expanders, thereby significantly improving the output power of the expander unit and the performance of the liquid compressed carbon dioxide energy storage system; utilizes the sequential connection of the dehumidifier, preheater, regenerator and high-temperature reheater to form a gradient heating of the liquid carbon dioxide in the liquid storage tank from a low-temperature liquid state to a high-temperature gaseous state, thereby realizing the gradient and efficient utilization of heat, and effectively reducing the heat exchange temperature difference and The heat required to heat the air heater of the closed-loop heat pump drying unit to the predetermined drying temperature is used to provide the air heater of the closed-loop heat pump drying unit with the heat required to heat the air heater to the predetermined drying temperature. In this way, the heat can be efficiently utilized, greatly improving the energy storage efficiency. In addition, compared with the traditional heat pump drying system, the closed-loop heat pump drying unit does not require a compressor and an expansion valve, and has a simpler structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 This is a schematic structural diagram of an energy storage system for liquid compressed carbon dioxide circulation coupled with heat pump drying according to an embodiment of the present invention.

[0013] Reference numerals:

[0014] Throttle valve 1, first compressor 2, second compressor 3, first cooler 4, first liquid storage tank 5, dehumidifier 6, air heater 7, drying chamber 8, preheater 9, regenerator 10, first high-temperature reheater 11, first expander 12, second high-temperature reheater 13, second expander 14, second cooler 15, cold storage device 16, second liquid storage tank 17, first intercooler 18, second intercooler 19, first hot tank 20, first cold tank 21, solar collector 22, second hot tank 23, second cold tank 24. DETAILED DESCRIPTION

[0015] 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, not all of the embodiments. 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.

[0016] The energy storage system of the liquid compressed carbon dioxide cycle coupled with heat pump drying in the embodiment of the present invention comprises an energy storage unit, a closed cycle heat pump drying unit, an energy release unit, a heat storage unit and a photothermal auxiliary unit. Figure 1As shown, the energy storage unit includes a throttle valve 1, a first compressor 2, a second compressor 3, a first cooler 4 and a first liquid storage tank 5, the outlet of the first cooler 4 is connected to the inlet of the first liquid storage tank 5; the closed-cycle heat pump drying unit includes a dehumidifier 6, an air heater 7 and a drying chamber 8, the first inlet of the dehumidifier 6 is connected to the outlet of the drying chamber 8, the second inlet of the dehumidifier 6 is connected to the outlet of the first liquid storage tank 5, the first outlet of the dehumidifier 6 is connected to the first inlet of the air heater 7, and the inlet of the drying chamber 8 is connected to the first outlet of the air heater 7; the energy release unit includes a preheater 9, a regenerator 10, a first high-temperature reheater 11, a first expander 12, and a second high-temperature reheater 13. , a second expander 14, a second cooler 15, a cold storage tank 16 and a second liquid storage tank 17, the first inlet of the preheater 9 is connected to the second outlet of the dehumidifier 6, the first outlet of the preheater 9 is connected to the first inlet of the regenerator 10, the first outlet of the regenerator 10 is connected to the first inlet of the first high-temperature reheater 11, the first outlet of the first high-temperature reheater 11 is connected to the inlet of the first expander 12, the outlet of the first expander 12 is connected to the first inlet of the second high-temperature reheater 13, the first outlet of the second high-temperature reheater 13 is connected to the inlet of the second expander 14, the outlet of the second expander 14 is connected to the second inlet of the regenerator 10, and the second outlet of the regenerator 10 is connected to the air heating The first inlet of the cold storage device 16 is connected to the outlet of the throttle valve 1, the first outlet of the cold storage device 16 is connected to the inlet of the first compressor 2, the second inlet of the cold storage device 16 is connected to the outlet of the second cooler 15, the second outlet of the cold storage device 16 is connected to the inlet of the second liquid storage tank 17, and the outlet of the second liquid storage tank 17 is connected to the inlet of the throttle valve 1; the thermal storage unit includes a first intercooler 18, a second intercooler 19, a first hot tank 20 and a first cold tank 21, the first inlet of the first intercooler 18 is connected to the outlet of the first compressor 2, the first outlet of the first intercooler 18 is connected to the inlet of the second compressor 2, and the second inlet of the cold storage device 16 is connected to the outlet of the second cooler 15. The second outlet of the cold storage device 16 is connected to the inlet of the second liquid storage tank 17, and the outlet of the second liquid storage tank 17 is connected to the inlet of the throttle valve 1. The inlet of the first intercooler 18 is connected to the outlet of the first cold tank 21, the second outlet of the first intercooler 18 is connected to the inlet of the first hot tank 20, the first inlet of the second intercooler 19 is connected to the outlet of the second compressor 3, the first outlet of the second intercooler 19 is connected to the inlet of the first cooler 4, the second inlet of the second intercooler 19 is connected to the outlet of the first cold tank 21, the second outlet of the second intercooler 19 is connected to the inlet of the first hot tank 20, the outlet of the first hot tank 20 is connected to the second inlet of the preheater 9, the second outlet of the preheater 9 is connected to the third inlet of the air heater 7, and the inlet of the first cold tank 21 is connected to the third outlet of the air heater 7;The photothermal auxiliary unit includes a solar collector 22, a second hot tank 23 and a second cold tank 24. The inlet of the solar collector 22 is connected to the outlet of the second cold tank 24, the outlet of the solar collector 22 is connected to the inlet of the second hot tank 23, the outlet of the second hot tank 23 is respectively connected to the second inlet of the first high-temperature reheater 11 and the second inlet of the second high-temperature reheater 13, and the inlet of the second cold tank 24 is respectively connected to the second outlet of the first high-temperature reheater 11 and the second outlet of the second high-temperature reheater 13. ;

[0017] In one embodiment of the present invention, the first compressor 2 and the second compressor 3 are further connected to a motor M to drive the first compressor 2 and the second compressor 3 by the motor M. The first expander 12 and the second expander 14 are further connected to a generator G to drive the generator G to generate electricity.

[0018] In a specific embodiment of the present invention, the throttle valve 1 may be an expansion valve.

[0019] The working process of the energy storage system of liquid compressed carbon dioxide cycle coupled with heat pump drying according to the above embodiment of the present invention is described in detail below.

[0020] Reference Figure 1 During the compression process, the liquid carbon dioxide in the second liquid storage tank 17 enters the throttle valve 1 to reduce temperature and pressure, and provides cooling capacity for the liquefaction of carbon dioxide in the energy release process in the cold storage device 16, consuming excess electric energy or valley electric energy. The first compressor 2 and the second compressor 3 are used to compress the gasified carbon dioxide to a high-temperature and high-pressure state. The high-temperature and high-pressure carbon dioxide is cooled by the first intercooler 18 and the second intercooler 19. The cooling water, as a heat transfer medium, absorbs heat and is stored in the first hot tank 20.

[0021] During the liquefaction storage process of the energy storage process, based on the characteristic that high-pressure carbon dioxide can be stored in liquid form at room temperature, the high-pressure gaseous carbon dioxide discharged from the second intercooler 19 directly enters the first cooler 4 for cooling and liquefaction, and the liquefied high-pressure carbon dioxide is stored in the first liquid storage tank 5.

[0022] During the expansion process, the liquid carbon dioxide in the first liquid storage tank 5 first passes through the dehumidifier 6 of the closed-loop heat pump drying unit to provide cooling capacity for the condensation and dehumidification of the humid air. The vaporized carbon dioxide then passes through the preheater 9 to absorb the heat of the hot water in the first heat tank 20. The heated carbon dioxide then enters the regenerator 10 to be reheated with the high-temperature carbon dioxide at the outlet of the second expander 14. The further preheated carbon dioxide is heated by the first high-temperature reheater 11 and the second high-temperature reheater 13. The high-pressure and high-temperature carbon dioxide then enters the first expander 12 and the second expander 14 to expand and do work. The medium-temperature carbon dioxide at the outlet of the regenerator 10 enters the air heater 7 in the closed-loop heat pump drying unit to heat the humid air at the outlet of the dehumidifier 11 to a predetermined drying temperature.

[0023] During the liquefaction and storage process of the energy release process, the carbon dioxide from the air heater 7 first enters the second cooler 15 to be cooled to room temperature, and then enters the cold storage tank 16 to absorb the cold energy of the liquid carbon dioxide at the outlet of the throttle valve 1 during the energy storage process. The cooled and liquefied carbon dioxide is stored in the second liquid storage tank 17.

[0024] The hot water in the first hot tank 20 first enters the preheater 9, and as a heat source, preheats the carbon dioxide at the outlet of the dehumidifier 6 to a certain temperature, then enters the air heater 7 to heat the cold dry air at the outlet of the dehumidifier 6 to a predetermined drying temperature, and then returns to the first cold tank 21.

[0025] In the photothermal auxiliary unit, the second hot tank 23 serves as a high-temperature hot tank, and the second cold tank 24 serves as a high-temperature cold tank. The solar thermal storage medium in the second cold tank 24 first enters the solar collector 22 to absorb solar heat. After reaching a high temperature, the solar thermal storage medium is stored in the second hot tank 23 and serves as a heat source for the first high-temperature reheater 11 and the second high-temperature reheater 13 during the energy release process. The cooled solar thermal storage medium then enters the second cold tank 24 for storage. By setting up a photothermal auxiliary unit and using the high-temperature thermal storage medium generated by the solar collector 22 as a heat source for the two high-temperature reheaters, the temperature of the carbon dioxide at the inlet of the two expanders can be further increased. In a specific embodiment of the present invention, the solar thermal storage medium may be heat transfer oil.

[0026] In the closed-cycle heat pump drying unit, the wet air at the outlet of the drying chamber 8 enters the dehumidifier 6 for condensation and dehumidification, and its cooling capacity is provided by the liquid carbon dioxide at the outlet of the first liquid storage tank 5. Then, it enters the air heater 7 to be heated to a predetermined drying temperature, and its heat is provided by the carbon dioxide at the outlet of the regenerator 10 and the hot water at the outlet of the preheater 9. After reaching the predetermined drying temperature, the hot dry air enters the drying chamber 8 for drying.

[0027] According to the energy storage system of the liquid compressed carbon dioxide cycle coupled with heat pump drying of the embodiment of the present invention, the liquid carbon dioxide in the liquid storage tank during the energy storage process is used to provide the cooling capacity required for condensation and dehumidification for the dehumidifier of the closed-cycle heat pump drying unit; the photothermal auxiliary unit is used to use the high-temperature solar energy storage medium that absorbs solar energy as the heat source for reheating before each stage of the expander, which significantly improves the output power of the expansion unit and the performance of the liquid compressed carbon dioxide energy storage system; the dehumidifier, preheater, regenerator and high-temperature reheater are connected in sequence to form a gradient heating of the liquid carbon dioxide in the liquid storage tank from a low-temperature liquid state to a high-temperature gaseous state, thereby realizing the gradient and efficient utilization of heat and effectively reducing the heat exchange temperature difference and The heat required to heat the air heater of the closed-loop heat pump drying unit to the predetermined drying temperature is used to provide the air heater of the closed-loop heat pump drying unit with the heat required to heat the air heater to the predetermined drying temperature. In this way, the heat can be efficiently utilized, greatly improving the energy storage efficiency. In addition, compared with the traditional heat pump drying system, the closed-loop heat pump drying unit does not require a compressor and an expansion valve, and has a simpler structure.

[0028] In the description of the present invention, 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. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. "Multiple" means two or more, unless otherwise clearly and specifically defined.

[0029] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" 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. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0030] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a 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, a first feature being "above", "above" or "above" a 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. A first feature being "below", "below" or "below" a 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.

[0031] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, unless they are contradictory.

[0032] It should be understood that the various parts of the present invention can be implemented by hardware, software, firmware or a combination thereof. In the above-mentioned embodiments, a plurality of steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented by hardware, as in another embodiment, it can be implemented by any one of the following technologies known in the art or their combination: a discrete logic circuit having a logic gate circuit for implementing a logic function for a data signal, a dedicated integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0033] A person skilled in the art may understand that all or part of the steps in the method for implementing the above-mentioned embodiment may be completed by instructing related hardware through a program, and the program may be stored in a computer-readable storage medium, which, when executed, includes one or a combination of the steps of the method embodiment.

[0034] In addition, each functional unit in each embodiment of the present invention may be integrated into a processing module, or each unit may exist physically separately, or two or more units may be integrated into one module. The above-mentioned integrated module may be implemented in the form of hardware or in the form of a software functional module. If the integrated module is implemented in the form of a software functional module and sold or used as an independent product, it may also be stored in a computer-readable storage medium.

[0035] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A liquid compressed carbon dioxide cycle coupled with heat pump drying energy storage system, characterized in that: It includes an energy storage unit, a closed-cycle heat pump drying unit, an energy release unit, a heat storage unit and a photothermal auxiliary unit, wherein: The energy storage unit includes a throttle valve, a first compressor, a second compressor, a first cooler and a first liquid storage tank, wherein the outlet of the first cooler is connected to the inlet of the first liquid storage tank; The closed-cycle heat pump drying unit comprises a dehumidifier, an air heater and a drying chamber, wherein a first inlet of the dehumidifier is connected to an outlet of the drying chamber, a second inlet of the dehumidifier is connected to an outlet of the first liquid storage tank, a first outlet of the dehumidifier is connected to a first inlet of the air heater, and an inlet of the drying chamber is connected to a first outlet of the air heater; The energy release unit includes a preheater, a regenerator, a first high-temperature reheater, a first expander, a second high-temperature reheater, a second expander, a second cooler, a cold storage tank, and a second liquid storage tank. The first inlet of the preheater is connected to the second outlet of the dehumidifier, the first outlet of the preheater is connected to the first inlet of the regenerator, the first outlet of the regenerator is connected to the first inlet of the first high-temperature reheater, the first outlet of the first high-temperature reheater is connected to the inlet of the first expander, the outlet of the first expander is connected to the first inlet of the second high-temperature reheater, and the first outlet of the second high-temperature reheater is connected to the first outlet of the second high-temperature reheater. connected to the inlet of the second expander, the outlet of the second expander is connected to the second inlet of the regenerator, the second outlet of the regenerator is connected to the second inlet of the air heater, the inlet of the second cooler is connected to the second outlet of the air heater, the first inlet of the cold accumulator is connected to the outlet of the throttle valve, the first outlet of the cold accumulator is connected to the inlet of the first compressor, the second inlet of the cold accumulator is connected to the outlet of the second cooler, the second outlet of the cold accumulator is connected to the inlet of the second liquid storage tank, and the outlet of the second liquid storage tank is connected to the inlet of the throttle valve; The thermal storage unit comprises a first intercooler, a second intercooler, a first hot tank and a first cold tank, wherein the first inlet of the first intercooler is connected to the outlet of the first compressor, the first outlet of the first intercooler is connected to the inlet of the second compressor, the second inlet of the first intercooler is connected to the outlet of the first cold tank, the second outlet of the first intercooler is connected to the inlet of the first hot tank, the first inlet of the second intercooler is connected to the outlet of the second compressor, the first outlet of the second intercooler is connected to the inlet of the first cooler, the second inlet of the second intercooler is connected to the outlet of the first cold tank, the second outlet of the second intercooler is connected to the inlet of the first hot tank, the outlet of the first hot tank is connected to the second inlet of the preheater, the second outlet of the preheater is connected to the third inlet of the air heater, and the inlet of the first cold tank is connected to the third outlet of the air heater; The photothermal auxiliary unit includes a solar collector, a second hot tank and a second cold tank. The inlet of the solar collector is connected to the outlet of the second cold tank, the outlet of the solar collector is connected to the inlet of the second hot tank, the outlet of the second hot tank is respectively connected to the second inlet of the first high-temperature reheater and the second inlet of the second high-temperature reheater, and the inlet of the second cold tank is respectively connected to the second outlet of the first high-temperature reheater and the second outlet of the second high-temperature reheater.

2. The energy storage system of liquid compressed carbon dioxide cycle coupled with heat pump drying according to claim 1 is characterized in that: The first compressor and the second compressor are also connected to an electric motor.

3. The energy storage system of liquid compressed carbon dioxide cycle coupled with heat pump drying according to claim 1 is characterized in that: The first expander and the second expander are also connected to a generator.

4. The energy storage system of liquid compressed carbon dioxide cycle coupled with heat pump drying according to claim 1 is characterized in that: The throttle valve is an expansion valve.

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