Liquid-liquid compressed carbon dioxide energy storage system for recovering waste heat of data center

Abstract

The invention provides a liquid-liquid compressed carbon dioxide energy storage system for recovering waste heat of a data center. The liquid-liquid compressed carbon dioxide energy storage system comprises a carbon dioxide liquid storage tank, an energy storage assembly, an energy release assembly and a data center cooling circulation loop. In the electric power valley period, low-pressure liquid carbon dioxide cold energy is recycled through the phase change cold accumulator, surplus electric power is consumed through the two-stage compressor, and high-pressure gas heat # imgabs0 # is recycled through the two-stage intercooler to provide energy for the energy release process; in the power peak period, the phase change heat accumulator is matched with heat capacity, waste heat of a data center is recycled, high-pressure liquid carbon dioxide is preheated, heat exchange of a reheater is optimized, # imgabs 1 # efficiency is improved, and meanwhile part of turbine exhaust waste heat is recycled for gas preheating in the energy storage process. Waste heat can be recovered while the cooling requirement of the data center is met, the energy loss of the data center is reduced, and meanwhile the energy storage efficiency of the system is improved.

Description

Technical Field

[0001] The present invention belongs to the field of electric energy storage, and in particular relates to a liquid-liquid compressed carbon dioxide energy storage system for recovering waste heat from a data center. Background Art

[0002] Compressed carbon dioxide energy storage technology is a new type of compressed gas energy storage technology with many advantages such as high energy storage density, low economic cost and long operating life. It is suitable for my country's large-scale long-term energy storage system construction and sustainable development needs, and has very broad development prospects.

[0003] At present, the high-pressure side of the compressed carbon dioxide system generally adopts supercritical or liquid storage, while the low-pressure side still adopts gaseous storage, which greatly limits the improvement of energy storage density and is also limited by the geographical environment. Therefore, the liquid carbon dioxide energy storage technology that stores carbon dioxide in a double-sided liquid phase has broad development prospects due to its advantages such as high energy storage density, flexible and compact structure, and low requirements for the geographical environment. At the same time, since data centers are generally large in scale and need to operate uninterruptedly, a stable supply of cold sources is required to dissipate heat for server chips, etc., and the remaining heat has the characteristics of relatively stable heat and high heat generation. The temperature of the cooling medium of a data center cooled by liquid cooling technology can reach 60-75°C, and directly discharging this heat will cause a lot of energy waste. Summary of the invention

[0004] In view of this, the present invention proposes a liquid-liquid compressed carbon dioxide energy storage system for recovering waste heat from data centers. Considering the characteristics of data centers operating all day, the heat capacity is matched by phase change heat storage devices during the energy release process to recover and utilize waste heat from data centers. At the same time, the air cooler is used to cool the liquid cooling medium again, providing a temperature-stable cold source for the data center to maintain continuous and stable operation of the system. The present invention can recover waste heat while meeting the cooling needs of the data center, reduce energy loss in the data center, and improve the energy storage efficiency of the system.

[0005] A liquid-liquid compressed carbon dioxide energy storage system for recovering waste heat from a data center, comprising a carbon dioxide liquid storage tank, an energy storage component, an energy release component and a data center cooling circulation loop; the carbon dioxide liquid storage tank comprises a low-pressure side carbon dioxide liquid storage tank and a high-pressure side carbon dioxide liquid storage tank; the energy storage component comprises a two-stage compressor and an energy storage heat exchange component; the outlet of the low-pressure liquid storage tank is connected to a phase-change cold storage device through a throttle valve I, the phase-change cold storage device is connected to a preheater, the preheater is connected to a compressor I, the compressor I is connected to a compressor II (7) through an intercooler I, and the compressor II The outlet is connected to the intercooler II and the condenser in sequence, and the outlet of the condenser is connected to the inlet of the high-pressure liquid storage tank through the throttle valve II; the energy release component includes a two-stage turbine and an energy release heat exchange component; the outlet of the high-pressure liquid storage tank is connected to the phase change heat accumulator through a carbon dioxide pump, the phase change heat accumulator is connected to the reheater I, the reheater I is connected to the turbine I, the turbine I is connected to the reheater II, the reheater II is connected to the turbine II, the outlet of the turbine II is connected to the cooler I and the precooler in sequence, the outlet of the precooler is connected to the phase change cold accumulator, and the phase change cold accumulator is connected to the inlet of the low-pressure liquid storage tank through the throttle valve III;

[0006] The low-temperature heat exchange medium storage tank, the precooler, the normal-temperature heat exchange medium storage tank, the pump I, and the preheater are sequentially connected to form a circulation loop; the low-temperature water storage tank is connected to the pump II, and the outlet of the pump II is simultaneously connected to the intercooler II and the intercooler I for shunting, and the outlets of the intercooler II and the intercooler I converge to the high-temperature water storage tank, and the outlet of the high-temperature water storage tank is simultaneously connected to the reheater II and the reheater I for shunting, and the outlets of the reheater II and the reheater I converge to the cooler II, and the cooler II is connected to the low-temperature water storage tank to finally form a circulation loop;

[0007] The data center cooling circulation loop comprises a data center (15), wherein the data center (15), a phase change heat storage device (13), and an air cooler (14) are sequentially connected to form a circulation loop.

[0008] Furthermore, during the power off-peak period, the power consumed by the compressors I and II is the surplus power during the power off-peak period; the low-pressure liquid storage tank releases low-temperature liquid carbon dioxide, and the pressure is adjusted by the throttle valve I to further reduce the temperature of carbon dioxide, and the cold is recovered by the phase change cold storage device to be gasified into gaseous carbon dioxide, and then the temperature of the gaseous carbon dioxide is increased by the preheater, and after entering the compressor I for pressurization, the temperature is reduced by the intercooler I, and the gaseous carbon dioxide enters the compressor II for pressurization again, and then the temperature is reduced by the intercooler II, and further condensed into liquid carbon dioxide by the condenser, and the liquid carbon dioxide is transported to the high-pressure liquid storage tank for storage after the pressure is adjusted by the throttle valve II; the normal temperature heat exchange medium flows out of the normal temperature heat exchange medium storage tank, and is transported to the preheater through the pump I to increase the temperature of the gaseous carbon dioxide, and the heat exchange medium that releases heat flows into the low-temperature heat exchange medium storage tank; low-temperature water flows out of the low-temperature water storage tank, and flows into the intercoolers II and I through the pump II respectively to absorb heat, and then converges into the high-temperature water storage tank for storage.

[0009] Furthermore, during the peak period of electricity, the turbine I and turbine II generate electricity through the generator to supply users for energy release; the high-pressure liquid carbon dioxide is released from the high-pressure liquid storage tank, and after the liquid carbon dioxide is stabilized by the carbon dioxide pump, it absorbs heat through the phase change heat accumulator to vaporize into high-pressure gaseous carbon dioxide, and the high-pressure gaseous carbon dioxide absorbs heat through the regenerator I to increase the temperature of the high-pressure gaseous carbon dioxide, and then expands and works through the turbine I to reduce the temperature and pressure, and the gaseous carbon dioxide continues to absorb heat and heat through the regenerator II to enter the turbine II to expand and work, and the temperature of the turbine exhaust enters the cooler I and then reduces, and the waste heat of the turbine exhaust is recovered through the precooler, and the temperature of the gaseous carbon dioxide is further reduced, and then passes through the phase change cold accumulator, using the cold energy stored in the phase change cold accumulator to ensure The gaseous carbon dioxide is liquefied into low-pressure liquid carbon dioxide, and the liquid carbon dioxide is returned to the low-pressure liquid storage tank for storage after the pressure is adjusted by the throttle valve III; the waste heat of the data center is absorbed by the liquid cooling medium, and the liquid cooling medium enters the phase change heat accumulator to release heat, and then is further cooled by the air cooler to reduce the temperature of the liquid cooling medium, ensuring that the liquid cooling medium returns to the data center at a stable temperature; high-temperature water flows out of the high-temperature water storage tank, enters the reheater II and reheater I respectively to release heat, and then merges into cooler II, ensuring that the low-temperature water returns to the low-temperature water storage tank at a stable temperature; the low-temperature heat exchange medium flows out of the low-temperature heat exchange medium storage tank, enters the precooler to absorb the turbine exhaust waste heat, and the normal temperature heat exchange medium returns to the normal temperature heat exchange medium storage tank for storage.

[0010] Preferably, after the liquid cooling medium releases heat in the phase change heat storage device, a natural cold source is introduced into the air cooler by blowing air to further reduce the temperature of the liquid cooling medium, thereby providing a cold source with a stable temperature for the data center.

[0011] Preferably, the heat exchange medium is methanol. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 Schematic diagram of the liquid-liquid compressed carbon dioxide energy storage system for recovering waste heat from a data center according to the present invention.

[0013] In the figure: 1- low-pressure liquid storage tank, 2- throttle valve I, 3- phase change cold storage device, 4- preheater, 5- compressor I, 6- intercooler I, 7- compressor II, 8- intercooler II, 9- condenser, 10- throttle valve II, 11- high-pressure liquid storage tank, 12- carbon dioxide pump, 13- phase change heat storage device, 14- air cooler, 15- data center, 16- reheater I, 17- turbine I, 18- reheater II, 19- turbine II, 20- cooler I, 21- precooler, 22- throttle valve III, 23- low-temperature methanol storage tank, 24- normal temperature methanol storage tank, 25- pump I, 26- high-temperature water storage tank, 27- cooler II, 28- low-temperature water storage tank, 29- pump II. DETAILED DESCRIPTION

[0014] The present invention provides a liquid-liquid compressed carbon dioxide energy storage system for recovering waste heat from a data center. The present invention is described below in conjunction with the accompanying drawings.

[0015] Figure 1 The figure shows the liquid-liquid compressed carbon dioxide energy storage system for recovering waste heat from a data center according to the present invention. The system mainly includes a carbon dioxide liquid storage tank, an energy storage component, an energy release component and a data center cooling circulation loop.

[0016] The carbon dioxide liquid storage tank comprises a low-pressure liquid storage tank 1 and a high-pressure liquid storage tank 11, and the carbon dioxide liquid storage tank is used to store liquid carbon dioxide.

[0017] The energy storage component includes a two-stage compressor and an energy storage heat exchange component; the outlet of the low-pressure liquid storage tank 1 is connected to the phase-change cold storage device 3 through a throttle valve Ⅰ, the phase-change cold storage device 3 is connected to the preheater 4, the preheater 4 is connected to the compressor Ⅰ, the compressor Ⅰ is connected to the compressor Ⅱ through the intercooler Ⅰ, the outlet of the compressor Ⅱ is connected to the intercooler Ⅱ and the condenser 9 in sequence, and the outlet of the condenser 9 is connected to the inlet of the high-pressure liquid storage tank 11 through the throttle valve Ⅱ.

[0018] The energy release component includes a two-stage turbine and an energy release heat exchange component; the outlet of the high-pressure liquid storage tank 11 is connected to the phase change heat accumulator 13 through the carbon dioxide pump 12, the phase change heat accumulator 13 is connected to the reheater I, the reheater I is connected to the turbine I, the turbine I is connected to the reheater II, the reheater II is connected to the turbine II, the turbine II outlet is connected to the cooler I and the precooler 21 in sequence, the precooler 21 outlet is connected to the phase change cold accumulator 3, and the phase change cold accumulator 3 is connected to the inlet of the low-pressure liquid storage tank 1 through the throttle valve III.

[0019] The energy storage heat exchange component and the energy release heat exchange component include a phase change cold storage device 3, a preheater 4, an intercooler I, an intercooler II, a condenser 9, a phase change heat storage device 13, a reheater I16, a reheater II, a cooler I, a precooler 21, a low temperature methanol storage tank 23, a normal temperature methanol storage tank 24, a pump I, a low temperature water storage tank 28, a pump II, and a high temperature water storage tank 26; the low temperature methanol storage tank 23, the precooler 21, the normal temperature methanol storage tank 24, the pump I25, and the preheater 4 are sequentially connected to form a circulation loop; the low temperature water storage tank 28 is connected to the pump II, and the outlet of the pump II is simultaneously connected to the intercooler II and the intercooler I for diversion, and the outlets of the intercooler II and the intercooler I converge at the high temperature water storage tank 26, and the outlet of the high temperature water storage tank 26 is simultaneously connected to the reheater II and the reheater I for diversion, and the outlets of the reheater II and the reheater I converge at the cooler II, and the cooler II is connected to the low temperature water storage tank 28, and finally a circulation loop is formed.

[0020] The data center cooling circulation loop includes a data center 15, a phase change heat storage device 13, and an air cooler 14; the data center 15, the phase change heat storage device 13, and the air cooler 14 are sequentially connected to form a circulation loop.

[0021] The energy storage and release operation strategy of the liquid-liquid compressed carbon dioxide energy storage system for recovering waste heat from the data center is as follows: during the power off period, the power consumed by compressors Ⅰ and Ⅱ is the surplus power during the power off period; the low-pressure liquid storage tank 1 releases low-temperature liquid carbon dioxide, and the pressure is adjusted by throttle valve Ⅰ to further reduce the temperature of carbon dioxide, and the cold is recovered by phase change cold storage device 3 to be gasified into gaseous carbon dioxide, and then the temperature of gaseous carbon dioxide is increased by preheater 4, and after entering compressor Ⅰ for pressurization, the temperature is reduced by intercooler Ⅰ; the gaseous carbon dioxide enters the compressor Machine II is pressurized again, and then the temperature is reduced by intercooler II, and further condensed into liquid carbon dioxide by condenser 9; the liquid carbon dioxide is pressure-regulated by throttle valve II and transported to high-pressure liquid storage tank 11 for storage; normal temperature methanol flows out from normal temperature methanol storage tank 24, and is transported to preheater 4 through pump I to increase the temperature of gaseous carbon dioxide, and the methanol that releases heat flows into low-temperature methanol storage tank 23; low-temperature water flows out from low-temperature water storage tank 28, and flows into intercooler II and intercooler I respectively through pump II to absorb heat, and then converges into high-temperature water storage tank 26 for storage.

[0022] During the peak period of electricity, turbine I and turbine II generate electricity through generators to supply users for energy release; high-pressure liquid carbon dioxide is released from the high-pressure liquid storage tank 11, and after the liquid carbon dioxide is stabilized by the carbon dioxide pump 12, it absorbs heat and vaporizes into high-pressure gaseous carbon dioxide through the phase change heat accumulator 13. The high-pressure gaseous carbon dioxide absorbs heat through the reheater I to increase the temperature of the high-pressure gaseous carbon dioxide, and then expands and works through turbine I to reduce the temperature and pressure. The gaseous carbon dioxide continues to absorb heat and heat up through the reheater II, and then enters turbine II to expand and work. The turbine exhaust enters the cooler I to reduce the temperature, and the turbine exhaust waste heat is recovered through the precooler 21. The temperature of the gaseous carbon dioxide is further reduced, and then passes through the phase change cold accumulator 3, using the cold energy stored in the phase change cold accumulator 3. , ensuring that gaseous carbon dioxide is liquefied into low-pressure liquid carbon dioxide, and the liquid carbon dioxide returns to the low-pressure liquid storage tank 1 for storage after the pressure is adjusted by the throttle valve III; the waste heat of the data center 15 is absorbed by the liquid cooling medium, and the liquid cooling medium enters the phase change heat accumulator 13 to release heat, and then is further cooled by the air cooler 14 to reduce the temperature of the liquid cooling medium, ensuring that the liquid cooling medium returns to the data center 15 at a stable temperature; high-temperature water flows out of the high-temperature water storage tank 26, enters the reheater II and the reheater I respectively to release heat, and then merges into the cooler II, ensuring that the low-temperature water returns to the low-temperature water storage tank 28 at a stable temperature; low-temperature methanol flows out of the low-temperature methanol storage tank 23, enters the precooler 21 to absorb the turbine exhaust waste heat, and the normal-temperature methanol returns to the normal-temperature methanol storage tank 24 for storage.

[0023] After the liquid cooling medium releases heat in the phase change heat storage device 13 , a natural cold source is introduced into the air cooler 14 by blowing air to further reduce the temperature of the liquid cooling medium, thereby providing a cold source with a stable temperature for the data center 15 .

[0024] The freezing point of methanol is lowered, and methanol is used as a heat exchange medium to preheat the low-temperature gaseous carbon dioxide in the energy storage process, thereby ensuring the stable operation of the preheater 4.

[0025] The throttle valve I is used to adjust the outlet pressure of the low-pressure liquid carbon dioxide to further reduce the temperature of the carbon dioxide, and this part of the cold energy is recovered in the phase change cold storage device 3 for liquefaction of the carbon dioxide at the turbine outlet, effectively solving the problem of uneven energy matching in the cold storage and heat exchange process.

[0026] After the turbine exhaust is cooled by cooler I, the sensible heat of the gaseous carbon dioxide is recovered by the precooler 21 and used to preheat the low-temperature gaseous carbon dioxide in the energy storage process, thereby reducing the hot end difference of the phase change regenerator 3 and improving efficiency.

[0027] In the energy storage process, the low-temperature water flowing through intercooler II and intercooler I is used to recover the compression heat, which is used to heat the gaseous carbon dioxide in regenerator II and regenerator I in the energy release process, thereby increasing the turbine work capacity and improving the cycle efficiency.

[0028] Considering that the heat capacity of carbon dioxide fluctuates greatly near the critical point, the heat exchanger may have a pinch point problem, resulting in reduced efficiency. During the energy storage process, the high-temperature gaseous carbon dioxide at the outlet of compressor II is cooled by intercooler II and further condensed into liquid carbon dioxide by condenser 9. At the same time, during the energy release process, the high-pressure liquid carbon dioxide absorbs heat in the phase change heat accumulator 13 and vaporizes into high-pressure gaseous carbon dioxide, which is then heated by the regenerator I to improve the energy grade. The energy storage process matches the heat capacity through intercooler II and condenser 9, and the energy release process matches the heat capacity through phase change heat accumulator 13 and regenerator I, thereby reducing energy loss and improving the heat exchanger. efficiency.

[0029] Considering that the data center 15 needs to be cooled all day, the phase change heat storage device 13 is used to match the heat capacity by utilizing its large heat capacity and wide heat storage temperature range, thereby achieving decoupling of the energy consumption process of the carbon dioxide energy storage system and the heat dissipation process of the data center.

[0030] This embodiment is only a preferred specific implementation of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A liquid-liquid compressed carbon dioxide energy storage system for recovering waste heat from a data center, comprising a carbon dioxide liquid storage tank, an energy storage component, an energy release component, and a data center cooling circulation loop; The carbon dioxide liquid storage tank comprises a low-pressure side carbon dioxide liquid storage tank and a high-pressure side carbon dioxide liquid storage tank; The energy storage component comprises a two-stage compressor and an energy storage heat exchange component; the outlet of the low-pressure liquid storage tank (1) is connected to the phase-change cold storage device (3) through a throttle valve I (2), the phase-change cold storage device (3) is connected to the preheater (4), the preheater (4) is connected to the compressor I (5), the compressor I (5) is connected to the compressor II (7) through an intercooler I (6), the outlet of the compressor II (7) is connected to the intercooler II (8) and the condenser (9) in sequence, and the outlet of the condenser (9) is connected to the inlet of the high-pressure liquid storage tank (11) through a throttle valve II (10); The energy release component comprises a two-stage turbine and an energy release heat exchange component; the outlet of the high-pressure liquid storage tank (11) is connected to the phase-change heat accumulator (13) through a carbon dioxide pump (12); the phase-change heat accumulator (13) is connected to a reheater I (16); the reheater I (16) is connected to a turbine I (17); the turbine I (17) is connected to a reheater II (18); the reheater II (18) is connected to a turbine II (19); the outlet of the turbine II (19) is connected to a cooler I (20) and a precooler (21) in sequence; the outlet of the precooler (21) is connected to the phase-change cold accumulator (3); the phase-change cold accumulator (3) is connected to the inlet of the low-pressure liquid storage tank (1) through a throttle valve III (22); The low-temperature heat exchange medium storage tank (23), the precooler (21), the normal-temperature heat exchange medium storage tank (24), the pump I (25), and the preheater (4) are sequentially connected to form a circulation loop; the low-temperature water storage tank (28) is connected to the pump II (29), and the outlet of the pump II (29) is simultaneously connected to the intercooler II (8) and the intercooler I (6) for flow separation; the outlets of the intercooler II (8) and the intercooler I (6) converge to the high-temperature water storage tank (26); the outlet of the high-temperature water storage tank (26) is simultaneously connected to the reheater II (18) and the reheater I (16) for flow separation; the outlets of the reheater II (18) and the reheater I (16) converge to the cooler II (27); the cooler II (27) is connected to the low-temperature water storage tank (28), and finally forms a circulation loop; The data center cooling circulation loop comprises a data center (15), wherein the data center (15), a phase change heat storage device (13), and an air cooler (14) are sequentially connected to form a circulation loop.

2. According to claim 1, a liquid-liquid compressed carbon dioxide energy storage system for recovering waste heat from a data center is characterized in that: During the power off-peak period, the power consumed by the compressor I (5) and the compressor II (7) is the surplus power during the power off-peak period; the low-pressure liquid storage tank (1) releases low-temperature liquid carbon dioxide, and the pressure is adjusted by the throttle valve I (2) to further reduce the temperature of the carbon dioxide, and the cold is recovered by the phase change cold storage device (3) to be gasified into gaseous carbon dioxide, and then the temperature of the gaseous carbon dioxide is increased by the preheater (4), and after entering the compressor I (5) for pressurization, the temperature is reduced by the intercooler I (6), and the gaseous carbon dioxide enters the compressor II (7) for pressurization again, and then the temperature is reduced by the intercooler II (8) to be further condensed. The gaseous carbon dioxide is condensed into liquid carbon dioxide by the device (9), and the liquid carbon dioxide is transferred to the high-pressure liquid storage tank (11) for storage after the pressure is adjusted by the throttle valve II (10); the normal temperature heat exchange medium flows out of the normal temperature heat exchange medium storage tank (24), and is transferred to the preheater (4) through the pump I (25) to increase the temperature of the gaseous carbon dioxide, and the heat exchange medium that releases heat flows into the low temperature heat exchange medium storage tank (23); the low temperature water flows out of the low temperature water storage tank (28), and flows into the intercooler II (8) and the intercooler I (6) respectively through the pump II (29), absorbs heat, and then converges into the high temperature water storage tank (26) for storage.

3. The liquid-liquid compressed carbon dioxide energy storage system for recovering waste heat from a data center according to claim 1, characterized in that: During the peak period of electricity, the turbine I (17) and turbine II (19) generate electricity through the generator to supply energy to users; the high-pressure liquid carbon dioxide is released from the high-pressure liquid storage tank (11), and after the liquid carbon dioxide is stabilized by the carbon dioxide pump (12), it absorbs heat through the phase change heat accumulator (13) and vaporizes into high-pressure gaseous carbon dioxide. The high-pressure gaseous carbon dioxide absorbs heat through the regenerator I (16) to increase the temperature of the high-pressure gaseous carbon dioxide, and then expands and works through the turbine I (17) to reduce the temperature and pressure. The gaseous carbon dioxide continues to absorb heat and heat through the regenerator II (18) and then enters the turbine II (19) to expand and work. The temperature of the turbine exhaust gas is reduced after entering the cooler I (20). The waste heat of the turbine exhaust gas is recovered through the precooler (21), and the temperature of the gaseous carbon dioxide is further reduced. Then, it passes through the phase change cold accumulator (3), and the cold energy stored in the phase change cold accumulator (3) is used to ensure that the gaseous carbon dioxide Carbon oxide is liquefied into low-pressure liquid carbon dioxide, and the liquid carbon dioxide is returned to the low-pressure liquid storage tank (1) for storage after the pressure is adjusted by the throttle valve III (22); the waste heat of the data center (15) is absorbed by the liquid cooling medium, and the liquid cooling medium enters the phase change heat storage device (13) to release heat, and then is further cooled by the air cooler (14) to reduce the temperature of the liquid cooling medium, so as to ensure that the liquid cooling medium returns to the data center (15) at a stable temperature; high-temperature water flows out of the high-temperature water storage tank (26), enters the reheater II (18) and the reheater I (16) respectively to release heat, and then flows into the cooler II (27), so as to ensure that the low-temperature water returns to the low-temperature water storage tank (28) at a stable temperature; the low-temperature heat exchange medium flows out of the low-temperature heat exchange medium storage tank (23), enters the precooler (21) to absorb the turbine exhaust waste heat, and the normal-temperature heat exchange medium returns to the normal-temperature heat exchange medium storage tank (24) for storage.

4. The liquid-liquid compressed carbon dioxide energy storage system for recovering waste heat from a data center according to claim 1 is characterized in that: After the liquid cooling medium releases heat in the phase change heat storage device (13), a natural cooling source is introduced into the air cooler (14) by blowing air to further reduce the temperature of the liquid cooling medium, thereby providing a cooling source with stable temperature for the data center (15).

5. A liquid-liquid compressed carbon dioxide energy storage system for recovering waste heat from a data center according to any one of claims 1 to 3, characterized in that: The heat exchange medium is methanol.

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