Liquid-liquid compression co2 energy storage system recovering data center waste heat

Abstract

The application provides a liquid-liquid compression carbon dioxide energy storage system for recycling waste heat of a data center, which comprises a carbon dioxide liquid storage tank, an energy storage assembly, an energy release assembly and a data center cooling circulation loop. During a power valley period, low-pressure liquid carbon dioxide cold energy is recycled through a phase change cold accumulator, a two-stage compressor consumes surplus power, and a two-stage intercooler recycles high-pressure gas heat to provide energy for an energy release process; during a power peak period, data center waste heat is recycled and utilized through a phase change heat accumulator matched with a heat capacity, high-pressure liquid carbon dioxide is preheated, heat exchange of a reheater is optimized, efficiency is improved, and part of turbine exhaust waste heat is recycled and utilized for gas preheating of the energy storage process. The application can meet the data center cooling demand while recycling waste heat, reducing energy loss of the data center, and improving energy storage efficiency of the system.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of electric energy storage, and particularly relates to a liquid-liquid compressed carbon dioxide energy storage system for recycling waste heat of a data center. BACKGROUND

[0002] The compressed carbon dioxide energy storage technology is a new compressed gas energy storage technology, which has the advantages of large energy storage density, low economic cost, long service life and the like, is suitable for the needs of large-scale long-time energy storage system construction and sustainable development in China, and has a very broad development prospect.

[0003] At present, the high-pressure side of the compressed carbon dioxide system generally adopts supercritical or liquid storage, and the low-pressure side still adopts gaseous storage, which greatly limits the improvement of the energy storage density and is limited by the geographical environment. Therefore, the liquid carbon dioxide energy storage technology with double-side liquid storage of carbon dioxide has a broad development prospect due to the advantages of large energy storage density, flexible and compact structure, small requirement for geographical environment and the like. At the same time, since the data center generally has a large scale and needs to be operated uninterruptedly, a stable cold source is needed to cool the server chips and the like, and the waste heat has the characteristics of relatively stable heat and large heat production. The temperature of the cooling medium of the data center cooled by the liquid cooling technology can reach 60-75℃, and the direct discharge of the heat will cause great energy waste. SUMMARY

[0004] Therefore, the present application provides a liquid-liquid compressed carbon dioxide energy storage system for recycling waste heat of a data center, which considers the characteristics of all-day operation of the data center, matches the heat capacity through the phase change heat accumulator in the energy releasing process, recycles and utilizes the waste heat of the data center, simultaneously cools the liquid cooling medium again by using the air cooler, provides a temperature-stable cold source for the data center, and maintains the continuous and stable operation of the system. The present application can recycle the waste heat while meeting the cooling demand of the data center, reduces the energy loss of the data center, and simultaneously improves the energy storage efficiency of the system.

[0005] The application discloses a liquid-liquid compression carbon dioxide energy storage system for recycling waste heat of a data center, which comprises a carbon dioxide liquid storage tank, an energy storage assembly, an energy release assembly and a data center cooling circulation loop.

[0006] The low-temperature heat exchange medium storage tank, the pre-cooler, the normal-temperature heat exchange medium storage tank, the pump I and the pre-heater are sequentially connected to form a circulation loop.

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

[0008] Further, during the power valley period, the power consumed by the compressor I and the compressor II is the surplus power during the power valley period; the low-pressure liquid storage tank releases low-temperature liquid carbon dioxide, the pressure of which is adjusted by the throttle valve I, the temperature of the carbon dioxide is further reduced, the cold energy is recovered by the phase change heat accumulator and is gasified into gaseous carbon dioxide, the temperature of the gaseous carbon dioxide is increased by the pre-heater, the gaseous carbon dioxide is pressurized by the compressor I, the temperature of the gaseous carbon dioxide is reduced by the intercooler I, the gaseous carbon dioxide is pressurized again by the compressor II, the temperature of the gaseous carbon dioxide is reduced by the intercooler II, the gaseous carbon dioxide is condensed into liquid carbon dioxide by the condenser, the pressure of the liquid carbon dioxide is adjusted by the throttle valve II, and the liquid carbon dioxide is transported to the high-pressure liquid storage tank for storage; the normal-temperature heat exchange medium flows out from the normal-temperature heat exchange medium storage tank, is transported to the pre-heater by the pump I, the temperature of the gaseous carbon dioxide is increased, the heat exchange medium releasing heat flows into the low-temperature heat exchange medium storage tank; the low-temperature water flows out from the low-temperature water storage tank, absorbs heat by the pump II, flows into the intercooler II and the intercooler I, and is converged into the high-temperature water storage tank.

[0009] Further, during the power peak, the turbine I and turbine II generate electricity through the generator to release energy for the user; the high-pressure liquid carbon dioxide is released from the high-pressure liquid tank, the liquid carbon dioxide is stabilized by the carbon dioxide pump, and the phase change heat accumulator absorbs heat to gasify the high-pressure gaseous carbon dioxide, 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 the turbine I expands to do work, and the temperature and pressure are reduced, the gaseous carbon dioxide continues to absorb heat through the regenerator II to increase the temperature, and then enters the turbine II to expand to do work, the turbine exhaust enters the cooler I to reduce the temperature, and the waste heat of the turbine exhaust is recovered through the pre-cooler, the temperature of the gaseous carbon dioxide is further reduced, and then passes through the phase change heat accumulator, and the cold energy stored in the phase change heat accumulator is used to ensure that the gaseous carbon dioxide is liquefied into low-pressure liquid carbon dioxide, the liquid carbon dioxide is adjusted in pressure by the throttle valve III and then stored in the low-pressure liquid tank; the waste heat of the data center is absorbed by the liquid cooling medium, the liquid cooling medium enters the phase change heat accumulator to release heat, and then passes through the air cooler to further cool the liquid cooling medium, so that the liquid cooling medium returns to the data center at a stable temperature; high-temperature water flows out of the high-temperature water tank, enters the reheater II and reheater I to release heat, and then flows into the cooler II to ensure that the low-temperature water returns to the low-temperature water tank at a stable temperature; the low-temperature heat exchange medium flows out of the low-temperature heat exchange medium tank, enters the pre-cooler to absorb the waste heat of the turbine exhaust, and the normal-temperature heat exchange medium returns to the normal-temperature heat exchange medium tank for storage.

[0010] Preferably, the liquid cooling medium releases heat in the phase change heat accumulator, and then further reduces the temperature of the liquid cooling medium by introducing natural cooling sources into the air cooler through air blowing, so as to provide a temperature-stable cooling source for the data center.

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

[0012] Figure 1 A schematic diagram of the liquid-liquid compression carbon dioxide energy storage system for recycling waste heat of a data center of the present application.

[0013] In the figure: 1-low pressure liquid storage tank, 2-throttle valve I, 3-phase change cold accumulator, 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 accumulator, 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 application provides a liquid-liquid compression carbon dioxide energy storage system for recycling data center waste heat, which is described below in conjunction with the accompanying drawings.

[0015] Figure 1 The liquid-liquid compression carbon dioxide energy storage system for recycling data center waste heat of the present application is shown, which mainly comprises a carbon dioxide liquid storage tank, an energy storage assembly and an energy release assembly, 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 carbon liquid storage tank 11, and is used for storing liquid carbon dioxide.

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

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

[0019] The energy storage heat exchange assembly and the energy release heat exchange assembly comprise a phase change cold accumulator 3, a preheater 4, an intercooler I, an intercooler II, a condenser 9, a phase change heat accumulator 13, a reheater I 16, a reheater II, a cooler I, a pre-cooler 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, a high-temperature water storage tank 26; the low-temperature methanol storage tank 23, the pre-cooler 21, the normal-temperature methanol 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 with the pump II, the outlet of the pump II is connected with the intercooler II and the intercooler I to branch, the outlets of the intercooler II and the intercooler I are merged into the high-temperature water storage tank 26, the outlet of the high-temperature water storage tank 26 is connected with the reheater II and the reheater I to branch, the outlets of the reheater II and the reheater I are merged into the cooler II, and the cooler II is connected with the low-temperature water storage tank 28 to finally form the circulation loop.

[0020] The data center cooling circulation loop comprises a data center 15, a phase change cold accumulator 13, and an air cooler 14; the data center 15, the phase change cold accumulator 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 compression carbon dioxide energy storage system for recycling waste heat of a data center is as follows: during the power valley period, the power consumed by the compressor I and the compressor II is the surplus power during the power valley period; the low-temperature liquid carbon dioxide released from the low-pressure liquid storage tank 1 is adjusted in pressure by the throttle valve I, is further reduced in temperature, is gasified into gaseous carbon dioxide by the phase change cold accumulator 3, is increased in temperature by the preheater 4, is pressurized by the compressor I, is reduced in temperature by the intercooler I, is pressurized again by the compressor II, is reduced in temperature by the intercooler II, and is condensed into liquid carbon dioxide by the condenser 9; the liquid carbon dioxide is transported to the high-pressure liquid storage tank 11 after being adjusted in pressure by the throttle valve II; the normal-temperature methanol flows out from the normal-temperature methanol storage tank 24, is transported to the preheater 4 by the pump I to increase the temperature of the gaseous carbon dioxide, and the methanol releasing heat flows into the low-temperature methanol storage tank 23; the low-temperature water flows out from the low-temperature water storage tank 28, flows into the intercooler II and the intercooler I by the pump II to absorb heat, and is merged into the high-temperature water storage tank 26.

[0022] During the power peak, turbine I and turbine II generate electricity through the generator to supply users for energy release; high-pressure liquid carbon dioxide is released from the high-pressure liquid tank 11, and the liquid carbon dioxide is stabilized by the carbon dioxide pump 12, then absorbs heat to gasify into high-pressure gaseous carbon dioxide through the phase change heat accumulator 13, the high-pressure gaseous carbon dioxide absorbs heat to increase the temperature of the high-pressure gaseous carbon dioxide through the reheater I, then the temperature and pressure are reduced after the expansion work of turbine I, the gaseous carbon dioxide continues to absorb heat to increase the temperature through the reheater II, then enters the turbine II to expand and do work, the turbine exhaust enters the cooler I to reduce the temperature, the waste heat of the turbine exhaust is recovered through the pre-cooler 21, the temperature of the gaseous carbon dioxide is further reduced, then 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 is liquefied into low-pressure liquid carbon dioxide, and the liquid carbon dioxide returns to the low-pressure liquid tank 1 after the pressure is adjusted by the throttle valve III for storage; the waste heat of the data center 15 is absorbed by the liquid cooling medium, the liquid cooling medium releases heat in the phase change heat accumulator 13, then is further cooled by the air cooler 14 to reduce the temperature of the liquid cooling medium, and the liquid cooling medium returns to the data center 15 at a stable temperature; the high-temperature water flows out from the high-temperature water tank 26, enters the reheater II and the reheater I to release heat respectively, and then flows into the cooler II to ensure that the low-temperature water returns to the low-temperature water tank 28 at a stable temperature; the low-temperature methanol flows out from the low-temperature methanol tank 23, enters the pre-cooler 21 to absorb the waste heat of the turbine exhaust, and the normal-temperature methanol returns to the normal-temperature methanol tank 24 for storage.

[0023] The liquid cooling medium releases heat in the phase change heat accumulator 13, and the temperature of the liquid cooling medium is further reduced in the air cooler 14 through the introduction of natural cooling source by blowing, so as to provide a temperature-stable cooling source for the data center 15.

[0024] The freezing point of methanol is reduced, and the methanol is used as a heat exchange medium to preheat the low-temperature gaseous carbon dioxide in the energy storage process, so as to ensure 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, further reduce the temperature of the carbon dioxide, and recycle the cold energy in the phase change cold accumulator 3 for the liquefaction of the turbine outlet carbon dioxide, so as to effectively solve the problem of uneven energy matching in the cold storage and heat exchange process.

[0026] The turbine exhaust is cooled by the cooler I, the sensible heat of the gaseous carbon dioxide is recovered through the pre-cooler 21, and the low-temperature gaseous carbon dioxide in the energy storage process is preheated, so as to reduce the hot end difference of the phase change cold accumulator 3 and improve the efficiency.

[0027] The low-temperature water flowing through the intercooler II and the intercooler I is used to recover the compression heat in the energy storage process, and is used to heat the gaseous carbon dioxide in the reheater II and the reheater I in the energy release process, so as to increase the turbine work capacity and improve the cycle efficiency.

[0028] Considering that the heat capacity of carbon dioxide fluctuates greatly near the critical point, the heat exchanger may have pinch point problem leading to reduced efficiency, the high-temperature gaseous carbon dioxide at the outlet of the compressor II in the energy storage process is cooled by the intercooler II to reduce the temperature, and is further condensed into liquid carbon dioxide by the condenser 9, while the high-pressure liquid carbon dioxide in the energy release process is vaporized into high-pressure gaseous carbon dioxide by absorbing heat in the phase-change heat accumulator 13, and is heated by the regenerator I to improve the energy grade, the heat capacity is matched by the intercooler II and the condenser 9 in the energy storage process, and the heat capacity is matched by the phase-change heat accumulator 13 and the regenerator I in the energy release process, so as to reduce the energy loss and improve the efficiency of the heat exchanger .

[0029] Considering that the data center 15 needs to be cooled all day, the heat capacity is matched by using the characteristics of the phase-change heat accumulator 13, such as large heat capacity and wide temperature range, to decouple the energy storage process and the heat dissipation process of the carbon dioxide energy storage system.

[0030] This embodiment is only a preferred specific implementation of the present application, but the protection scope of the present application is not limited to this, any person skilled in the art can easily think of changes or replacements within the technical range disclosed by the present application, which should be covered in the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

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

2. The liquid-liquid compressed carbon dioxide energy storage system for recovering waste heat from a data center of claim 1, wherein, In the power valley, the power consumed by the compressor I (5) and the compressor II (7) is the surplus power in the power valley; the low-pressure liquid tank (1) releases low-temperature liquid carbon dioxide, which is adjusted in pressure by the throttle valve I (2), further reduces the temperature of the carbon dioxide, and recovers the cold energy by the phase change cold accumulator (3) to gasify the carbon dioxide into gaseous carbon dioxide, which is then heated by the preheater (4) to increase the temperature of the gaseous carbon dioxide, enters the compressor I (5) to be pressurized, and then passes through the intercooler I (6) to reduce the temperature; the gaseous carbon dioxide enters the compressor II (7) to be pressurized again, and then passes through the intercooler II (8) to reduce the temperature, and is further condensed into liquid carbon dioxide by the condenser (9); the liquid carbon dioxide is adjusted in pressure by the throttle valve II (10) and then transported to the high-pressure liquid tank (11) for storage; the normal-temperature heat exchange medium flows out from the normal-temperature heat exchange medium tank (24), is transported to the preheater (4) by 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 tank (23); the low-temperature water flows out from the low-temperature water tank (28), flows into the intercooler II (8) and the intercooler I (6) respectively by the pump II (29) to absorb heat, and then converges to enter the high-temperature water tank (26) for storage.

3. The liquid-liquid compressed carbon dioxide energy storage system for recovering waste heat from a data center of claim 1, wherein, At the power peak, the turbine I (17) and turbine II (19) through the generator to produce electricity for users to release energy; high pressure liquid carbon dioxide from the high pressure liquid tank (11) release, the liquid carbon dioxide through carbon dioxide pump (12) pressure stabilization, through the phase change heat accumulator (13) absorption of heat gasification into high pressure gaseous carbon dioxide, the high pressure gaseous carbon dioxide through regenerator I (16) absorption of heat, improve the high pressure gaseous carbon dioxide temperature, after through turbine I (17) expansion work temperature pressure reduction, the gaseous carbon dioxide continues through regenerator II (18) heat after entering turbine II (19) expansion work, turbine exhaust into the cooler I (20) temperature reduction, through the pre-cooler (21) recovery turbine exhaust waste heat, the gaseous carbon dioxide temperature further reduction, after through the phase change cold accumulator (3), using the phase change cold accumulator (3) storage of cold energy, ensure the gaseous carbon dioxide liquefaction into low pressure liquid carbon dioxide, the liquid carbon dioxide through the throttle valve III (22) pressure regulation after return to the low pressure liquid tank (1) storage; the data center (15) waste heat is absorbed by liquid cooling medium, the liquid cooling medium into phase change heat accumulator (13) release heat, after through the air cooler (14) further cooling, reduce the temperature of the liquid cooling medium, ensure the liquid cooling medium with stable temperature back to the data center (15); high temperature water from the high temperature water tank (26) flow out, respectively into the reheater II (18), reheater I (16) release heat after into cooler II (27), ensure the low temperature water with stable temperature back to low temperature water tank (28); low temperature heat exchange medium from the low temperature heat exchange medium storage tank (23) flow out, into the pre-cooler (21) absorption of turbine exhaust waste heat, the normal temperature heat exchange medium return to the normal temperature heat exchange medium storage tank (24) storage.

4. The liquid-liquid compressed carbon dioxide energy storage system for recovering waste heat from a data center of claim 3, wherein, The liquid cooling medium in phase change heat accumulator (13) release heat, in air cooler (14) through the introduction of natural cooling source further reduce the temperature of the liquid cooling medium, for the data center (15) to provide temperature stable cooling source.

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

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