A carbon dioxide-based data center cooling system

Abstract

This invention discloses a carbon dioxide-based data center cooling system, belonging to the field of data center thermal management technology. The system includes a cooling device, at least one storage tank, a coolant distribution unit, an inlet manifold, and an outlet manifold. The cryogenic liquid carbon dioxide produced by the cooling device is stored in the storage tank and transported to server racks within the data center via the distribution unit and pipelines to cool high-power AI chips. The cooled working fluid returns to the cooling device for recycling. The system provides two cooling implementation methods: one is direct cooling of the chips with liquid carbon dioxide; the other is indirect cooling through an independent carbon dioxide circulation loop formed by an intermediate heat exchanger. Furthermore, the system integrates a waste heat recovery unit, which can use the compression heat generated by the cooling device for power generation or district heating. This invention utilizes carbon dioxide as the working fluid to achieve efficient cooling and comprehensive energy utilization for data centers, offering advantages such as high energy efficiency and environmental friendliness.

Description

Technical Field

[0001] This invention relates to the field of data center infrastructure and thermal management technology, and more specifically, to a carbon dioxide-based data center cooling system. Background Technology

[0002] With the rapid development of artificial intelligence and high-performance computing, the power consumption and heat dissipation density of central processing units (CPUs) and graphics processing units (GPUs) in large-scale data centers are increasing exponentially. The waste heat generated has become a key bottleneck restricting the improvement of computing power and energy efficiency. Traditional air cooling methods are approaching their physical limits, while the widely used liquid cooling technology can improve heat dissipation efficiency, but the mechanical refrigeration system it relies on consumes a huge amount of energy, and a large amount of low-grade waste heat is directly discharged, resulting in serious energy waste. At the same time, current refrigeration systems widely use synthetic refrigerants with high global warming potential, which have significant environmental impacts during production, operation, and leakage.

[0003] Furthermore, existing data center cooling architectures are often single-function, with cooling systems and energy recovery systems operating independently and lacking deep synergy. Solutions for waste heat recovery are typically complex and have long payback periods, hindering large-scale deployment. Therefore, the industry urgently needs a technological solution that can fundamentally change the energy flow pattern of data centers—namely, developing an integrated thermal management solution that can address the challenges of extremely high heat flux density cooling, convert waste heat into usable energy, and is environmentally friendly—to achieve substantial reductions in data center energy consumption and sustainable development. Summary of the Invention

[0004] In view of the above-mentioned technical problems in related technologies, the present invention proposes a carbon dioxide-based data center cooling system that can overcome the above-mentioned shortcomings of the prior art.

[0005] To achieve the above-mentioned technical objectives, the technical solution of the present invention is implemented as follows: A carbon dioxide-based data center cooling system; This carbon dioxide-based data center cooling system is used to cool server racks within a large data center. The server racks house high-power AI chips. The system comprises: a cooling device for producing cryogenic liquid carbon dioxide; at least one storage tank for storing the liquid carbon dioxide produced by the cooling device; a coolant distribution unit located within the large data center for receiving liquid carbon dioxide from the first storage tank and distributing its flow; an inlet manifold connecting the coolant distribution unit and the server rack for transporting the liquid carbon dioxide; and an outlet manifold connecting the server rack and the coolant distribution unit for collecting the carbon dioxide working fluid after it has absorbed heat. The carbon dioxide working fluid after absorbing heat from the AI ​​chips in the server rack is returned to the cooling device for circulation.

[0006] Further, the cooling device includes: at least one carbon dioxide compressor for compressing gaseous carbon dioxide; a heat exchanger for receiving high-temperature, high-pressure carbon dioxide gas from the carbon dioxide compressor and condensing it into liquid while releasing the heat of compression; an energy-saving device for recovering the cold energy released by the carbon dioxide working fluid before expansion; a first expansion valve and a second expansion valve for throttling and expanding the high-pressure liquid carbon dioxide from the heat exchanger, causing it to transform into a low-temperature, low-pressure gas-liquid two-phase state; wherein the expanded low-temperature carbon dioxide working fluid enters the at least one first storage tank and / or the second storage tank.

[0007] Furthermore, it also includes a waste heat recovery power generation unit, which recovers the compression heat carried by the carbon dioxide working fluid flowing through the first heat exchanger and converts it into electrical energy; the waste heat recovery power generation unit includes a power turbine, a generator connected to the power turbine, and a cooling device for cooling the carbon dioxide working fluid after it has done work.

[0008] Furthermore, the waste heat recovery power generation unit also includes a booster heater, which provides additional heat to the carbon dioxide working fluid of the waste heat recovery power generation unit through a heat exchanger. The heat source of the booster heater is selected from solar energy, wind energy or geothermal energy.

[0009] Furthermore, the liquid carbon dioxide produced by the cooling device is directly transported to the main inlet pipe through the coolant distribution unit for direct cooling of the AI ​​chips inside the cabinet.

[0010] Furthermore, the cabinet is equipped with a cold plate for cooling the AI ​​chip, which is either an immersion cold plate or a liquid-cooled cold plate.

[0011] Furthermore, it also includes an independent carbon dioxide circulation loop located outside the cooling device. The independent carbon dioxide circulation loop includes: a second storage tank; a first coolant circulation pump and a third expansion valve. The inlet of the first coolant circulation pump is connected to the second storage tank, and the outlet passes sequentially through the third expansion valve, the coolant distribution unit, the inlet manifold, the cabinet equipped with the AI ​​chip, and the outlet manifold before returning to the first storage tank. The second storage tank or the independent carbon dioxide circulation loop is provided with a heat exchange structure for heat exchange with the cooling device, so as to utilize the cooling capacity provided by the cooling device to cool the carbon dioxide working fluid in the independent carbon dioxide circulation loop.

[0012] Furthermore, the cabinet is equipped with a cold plate for cooling the AI ​​chip, which is either an immersion cold plate or a liquid-cooled cold plate.

[0013] Furthermore, the system also includes an indoor heat exchanger and / or chiller unit for cooling the interior space of the data center, the cold source of which is supplied by the second storage tank.

[0014] Furthermore, the heat exchanger is also connected to a first heat exchanger for supplying the recovered compressed heat to the district heating system.

[0015] The beneficial effects of this invention are as follows: By constructing a circulating system with carbon dioxide as the core cooling medium and innovatively integrating a high-efficiency heat pump cycle, chip-level precision cooling, and waste heat recovery for power generation or heating, the system can directly address the severe heat dissipation challenges of high-density AI chips, significantly reducing the energy consumption of the cooling process itself. Furthermore, by systematically converting traditionally wasteful compression heat into electrical energy or usable thermal energy, the system achieves a full-chain efficiency improvement in data center energy from input, use, to recycling. This solution not only provides two flexible and configurable cooling paths—direct and indirect—to adapt to different needs, but also comprehensively improves the energy utilization rate and environmental friendliness of data centers, providing key technological support for the construction of next-generation green data centers. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of a first embodiment of a carbon dioxide-based data center cooling system according to an embodiment of the present invention; Figure 2 This is a schematic diagram of a second embodiment of a carbon dioxide-based data center cooling system according to an embodiment of the present invention; In the diagram: 1. Large data center; 2. Server rack; 3. Server rack group; 4. Inlet manifold; 5. Outlet manifold; 6. Coolant distribution unit; 7. Indoor heat exchanger; 8. Cooling device; 9. Carbon dioxide compressor; 10. Heat exchanger; 11. Energy-saving device; 12-1. First expansion valve; 12-2. Second expansion valve; 13. First storage tank; 14. Second storage tank; 16. Chiller unit; 17. Circulation pump; 18. Flow regulating valve; 19-1. First coolant circulation pump; 19-2. Second coolant circulation pump; 20-1. Third expansion valve; 20-2. Fourth expansion valve; 21-1. First heat exchanger; 22. Cooling equipment; 23-1. First valve; 23-2. Second valve; 24. Controller; 24-1. Flow controller; 25. Heat exchanger; 26. Booster heater; 27. Power turbine; 28. Generator; 29. ​​Feed pump. Detailed Implementation

[0018] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention are within the scope of protection of the present invention.

[0019] like Figure 1-2 As shown in the figure, a carbon dioxide-based data center cooling system according to an embodiment of the present invention is used to cool a rack 2 in a large data center 1. The rack 2 is equipped with a high-power AI chip. The system is characterized by comprising: a cooling device 8 for producing low-temperature liquid carbon dioxide; at least one storage tank 13, 14 for storing the liquid carbon dioxide produced by the cooling device 8; a coolant distribution unit 6 disposed in the large data center 1 for receiving liquid carbon dioxide from the first storage tank 13 and distributing the flow; an inlet manifold 4 connecting the coolant distribution unit 6 and the rack 2 for transporting liquid carbon dioxide; and an outlet manifold 5 connecting the rack 2 and the coolant distribution unit 6 for collecting the carbon dioxide working fluid after absorbing heat. The carbon dioxide working fluid after absorbing heat from the AI ​​chip in the rack 2 is returned to the cooling device 8 for circulation.

[0020] According to an embodiment of the present invention, a data center cooling system based on carbon dioxide is provided. In a specific embodiment, the cooling device 8 includes: at least one carbon dioxide compressor 9 for compressing gaseous carbon dioxide; a heat exchanger 10 for receiving high-temperature, high-pressure carbon dioxide gas from the carbon dioxide compressor 9 and condensing it into liquid while releasing the heat of compression; an energy-saving device 11 for recovering the cold energy released by the carbon dioxide working fluid before expansion; a first expansion valve 12-1 and a second expansion valve 12-2 for throttling and expanding the high-pressure liquid carbon dioxide from the heat exchanger 10, transforming it into a low-temperature, low-pressure gas-liquid two-phase state; wherein the expanded low-temperature carbon dioxide working fluid enters at least one first storage tank 13 and / or a second storage tank 14.

[0021] According to an embodiment of the present invention, a data center cooling system based on carbon dioxide is further comprising a waste heat recovery power generation unit in a certain specific embodiment. The waste heat recovery power generation unit recovers the compression heat carried by the carbon dioxide working fluid flowing through the heat exchanger 10 through a first heat exchanger 21-1 and converts it into electrical energy. The waste heat recovery power generation unit includes a power turbine 27, a generator 28 connected to the power turbine 27, and a cooling device 22 for cooling the carbon dioxide working fluid after it has done work.

[0022] According to an embodiment of the present invention, a data center cooling system based on carbon dioxide is provided. In a specific embodiment, the waste heat recovery power generation unit further includes a booster heater 26. The booster heater 26 provides additional heat to the carbon dioxide working fluid of the waste heat recovery power generation unit through a heat exchanger 25. The heat source of the booster heater 26 is selected from solar energy, wind energy or geothermal energy.

[0023] According to an embodiment of the present invention, a data center cooling system based on carbon dioxide is provided. In a specific embodiment, the liquid carbon dioxide produced by the cooling device 8 is directly transported to the liquid inlet manifold 4 through the coolant distribution unit 6 to directly cool the AI ​​chips in the cabinet 2.

[0024] According to an embodiment of the present invention, a carbon dioxide-based data center cooling system is provided, in a specific embodiment, a cold plate for cooling the AI ​​chip is provided inside the cabinet 2, the cold plate being an immersion cold plate or a liquid-cooled cold plate.

[0025] According to an embodiment of the present invention, a data center cooling system based on carbon dioxide, in a specific embodiment, further includes an independent carbon dioxide circulation loop disposed outside the cooling device 8. The independent carbon dioxide circulation loop includes: a second storage tank 14; a first coolant circulation pump 19-1 and a third expansion valve 20-1. The inlet of the first coolant circulation pump 19-1 is connected to the second storage tank 14, and the outlet passes sequentially through the third expansion valve 20-1, the coolant distribution unit 6, the inlet manifold 4, the cabinet 2 equipped with the AI ​​chip, and the outlet manifold 5 before returning to the first storage tank 13. The second storage tank 14 or the independent carbon dioxide circulation loop is provided with a heat exchange structure for heat exchange with the cooling device 8, so as to utilize the cooling capacity provided by the cooling device 8 to cool the carbon dioxide working fluid in the independent carbon dioxide circulation loop.

[0026] According to an embodiment of the present invention, a carbon dioxide-based data center cooling system is provided, in a specific embodiment, a cold plate for cooling the AI ​​chip is provided inside the cabinet 2, the cold plate being an immersion cold plate or a liquid-cooled cold plate.

[0027] According to an embodiment of the present invention, a carbon dioxide-based data center cooling system further includes, in a specific embodiment, an indoor heat exchanger 7 and / or a chiller unit 16 for cooling the interior space of the data center, wherein the cold source for the indoor heat exchanger 7 and / or the chiller unit 16 is supplied by the second storage tank 14.

[0028] According to an embodiment of the present invention, a carbon dioxide-based data center cooling system is provided. In a specific embodiment, the heat exchanger 10 is further connected to a first heat exchanger 21-1 for supplying the recovered compressed heat to the district heating system.

[0029] To facilitate understanding of the above technical solutions of the present invention, the following detailed description of the above technical solutions of the present invention will be provided through specific usage methods.

[0030] In practical applications, this invention, based on a carbon dioxide-based data center cooling system, proposes two fundamental solutions to address the cooling problem of AI chips in large data centers. Solutions one and two share common characteristics, and their component configurations are interchangeable. Therefore, in practical applications, the system can be expanded and upgraded according to regional and social needs and cost control requirements. By integrating these two fundamental solutions, construction costs can be further optimized.

[0031] Both of these methods are used for cooling such as Figure 1 , Figure 2The large data center 1 shown is located within this data center. AI chips installed in racks 2 generate significant waste heat, with a power output of up to 150 megawatts. Several racks 2 are arranged in rows to form rack groups 3, which are supplied with fully cooled liquid carbon dioxide via a coolant distribution unit 6.

[0032] Liquid carbon dioxide coolant is delivered to each rack 2 containing AI chips via the inlet manifold 4. After absorbing waste heat from each rack 2, the coolant is temporarily stored in the outlet manifold 5. To ensure the safe operation, high performance, and extended lifespan of the AI ​​chips, the properties of liquid carbon dioxide are utilized to control the temperature of the AI ​​chips at approximately 30°C through immersion cold plates or liquid-cooled cold plates, employing either two-phase or single-phase heat exchange modes, thereby achieving efficient waste heat transfer.

[0033] For high-power AI chips, a two-phase evaporation immersion cold plate is required. Single-phase liquid or gas-liquid two-phase mixed carbon dioxide collected in the main outlet pipe 5 is transported to the coolant distribution unit 6 and then returned to the cooling device 8. The system monitors and adjusts the temperature and pressure within the coolant pipeline in real time to ensure safe and stable system operation. Simultaneously, the coolant distribution unit 6 controls the coolant flow distribution.

[0034] Within Data Center 1, another major cooling task is the air conditioning and cooling of the server rack area 3, office area, and open space, with a total building area of ​​37,200 square meters or more. The air conditioning system of Data Center 1 operates as follows: Circulation pump 17 and flow control valve 18 drive conventional coolant to circulate in indoor heat exchanger 7, achieving space cooling. To maintain the air conditioning and cooling needs of this area, a chiller unit 16 with a power of approximately 5 MW can be configured. Liquid carbon dioxide is supplied through two routes: one route is from the second storage tank 14 via the third expansion valve 20-1 and the first coolant circulation pump 19-1 to the chiller unit 16; the other route is from the first storage tank 13 via the fourth expansion valve 20-2 and the second coolant circulation pump 19-2 to the coolant distribution unit 6. Typical operating parameters for this cooling scheme are: the temperature of liquid carbon dioxide in the second storage tank 14 and the first storage tank 13 is maintained at approximately 8°C.

[0035] Option 1 This embodiment uses liquid carbon dioxide to directly cool the AI ​​chip. The liquid carbon dioxide in the first storage tank 13 is directly produced by the carbon dioxide heat pump circulation system equipped with the cooling device 8. Similarly, the circulating coolant in the second storage tank 14 is also directly produced by the same heat pump circulation system. For a large data center 1 with a total AI chip power consumption of approximately 500 megawatts, multiple carbon dioxide compressors 9 need to be configured in a matrix layout and uniformly controlled by a control system. The power of a single compressor is approximately 22 kilowatts. The total heat generated during the compressor compression process is approximately 173 megawatts, with a temperature reaching 62°C. This heat is recovered and utilized in the condenser 10, where gaseous carbon dioxide is condensed into high-pressure, high-temperature liquid carbon dioxide at a temperature of approximately 30°C. Subsequently, the liquid carbon dioxide flows through the first expansion valve 12-1 and the second expansion valve 12-2 arranged in parallel, entering the expansion and depressurization stage. The excess heat generated during this process is recovered by the energy-saving device 11.

[0036] After expansion, liquid carbon dioxide transforms into a low-pressure, low-temperature gas-liquid two-phase state at approximately 4.2 MPa and 8°C. Following gas-liquid separation, the liquid carbon dioxide is stored in the first storage tank 13 and the second storage tank 14, with cooling capacities of approximately 145 MW and 6 MW respectively. Through the carbon dioxide heat pump circulation system within the cooling device 8, a total cooling capacity of approximately 151 MW can be generated. This system employs a direct expansion refrigeration architecture, providing a cooling source for the AI ​​chip cooling and the chiller unit 16, offering advantages such as high control precision and good economic efficiency.

[0037] In this embodiment, the heat of compression generated by the circulation system is transferred to the condenser 10 for recovery and further converted into electrical energy output. Approximately 173 MW of heat of compression, at a temperature of around 60°C, is transferred to the carbon dioxide power circulation system via a first heat exchanger 21-1 connected to the condenser 10. This power circulation system is specifically equipped with a booster heater 26, which is controlled by a controller 24. The booster heater 26 preferentially uses free clean energy sources such as solar, wind, and geothermal energy, and the heat source temperature must be higher than 90°C. The heat energy provided by the booster heater 26 is absorbed by the heat exchanger 25, which is equipped with a flow controller 24-1, and transferred to the carbon dioxide power circulation system. The high-pressure, high-temperature gaseous carbon dioxide drives the power turbine 27 to perform work, which drives the generator 28 to generate electricity, with a power output of approximately 15 MW. For reference, if the booster heater is not activated, the power output of the system is approximately 15 MW. After performing work, the carbon dioxide gas, whose temperature drops to 30°C, is cooled by cooling equipment such as a cooling tower 22, and becomes liquid carbon dioxide with a temperature below 25°C. It is then transported back to the first heat exchanger 21-1 by the feed pump 29 to complete the cycle.

[0038] With the cooling unit 8 equipped with this carbon dioxide power cycle system, approximately 68% of the input power of the compressor 9 can be recovered and reused. If combined with the booster heater 26 utilizing clean energy, the power generation of the power turbine 27 is expected to be further increased, even exceeding the input power of the compressor 9 in the cooling unit 8.

[0039] Option 2 This embodiment uses indirect cooling with liquid carbon dioxide, such as Figure 2 As shown, cooling is implemented for the AI ​​chip, which has a total power consumption of approximately 500 megawatts. The main structure of Data Center 1 is... Figure 1 Liquid carbon dioxide at a temperature of approximately 5°C is supplied by a first storage tank 13 located outside the cooling device 8. Figure 2 As shown, the system includes a second storage tank 14, which serves as an intermediate heat exchanger. Its function is to absorb the 8°C cooling capacity provided by the cooling device 8 and store and transport liquid carbon dioxide at approximately 10°C via a second coolant circulation pump 19-2. A fourth expansion valve 20-2 is also installed in the circulation loop to further reduce the temperature of the liquid carbon dioxide to 5°C or even lower. The circulation path of the liquid carbon dioxide is: first storage tank 13 → second coolant circulation pump 19-2 → fourth expansion valve 20-2 → coolant distribution unit 6 → inlet manifold 4 → cabinet 2 → outlet manifold 5 → coolant distribution unit 6 → second storage tank 14 → first storage tank 13.

[0040] The advantage of this independent carbon dioxide circulation loop is that its thermal parameters can be independently adjusted and set, unaffected by the operating status of the cooling device 8. This implementation not only facilitates the operation and maintenance management of the entire system, but also significantly improves the flexibility of selecting the cooling device 8. For example, a hydrofluorocarbon heat pump system or other natural working fluid heat pump system can be used to replace the original carbon dioxide heat pump system. Figure 2 The component functions of the intermediate cooling device 8 and Figure 1 The efficiency remains consistent. Calculations show that, including the heat exchange efficiency of the intermediate heat exchanger 13, the energy utilization efficiency of this carbon dioxide circulation loop is approximately 83%.

[0041] If the cooling device 8 still uses a carbon dioxide heat pump system, its compressor power consumption is approximately 29 MW, the condenser 10 operates at 70°C, and the heat dissipation reaches 214 MW. Of this, approximately 180 MW of cooling capacity is supplied to the first storage tank 13, and approximately 6 MW is supplied to the chiller unit 16. Based on this cooling capacity, the indoor heat exchanger 7 can output approximately 5 MW of cooling capacity, maintaining the space temperature within the data center at 20°C. In summary, the cooling device 8 proposed in this patent can provide a total cooling capacity of approximately 186 MW.

[0042] Furthermore, the waste heat generated from AI chip cooling and space air conditioning within the data center can be recovered through the condenser 10 of the cooling device 8 and its associated first heat exchanger 21-1 for use in district heating. In a district heating scenario, when the outlet temperature of the condenser 10 is approximately 18°C, it can heat the 10°C heating return water to 50°C, outputting approximately 182 megawatts of heat. The flow rate of the district heating return water can be adjusted according to the needs of the district environment via the first valve 23-1 and the second valve 23-2.

[0043] The cooling solution proposed in this invention is suitable for ultra-large data centers with a building area of ​​approximately 37,200 square meters and a total AI chip power consumption of 500 megawatts. Both the first and second implementation methods possess unique technical advantages over traditional cooling methods, with the following performance coefficients: the first implementation method has a heating performance coefficient of 7.7 and a cooling performance coefficient of 6; the second implementation method has a heating performance coefficient of 7.5 and a cooling performance coefficient of 6.5.

[0044] In summary, by utilizing the technical solution of this invention, a circulating system with carbon dioxide as the core cooling medium is constructed. This system innovatively integrates a high-efficiency heat pump cycle, chip-level precision cooling, and waste heat recovery for power generation or heating. This enables the system to directly address the severe heat dissipation challenges of high-density AI chips, significantly reducing the energy consumption of the cooling process itself. Furthermore, by systematically converting traditionally wasteful compression heat into electricity or usable heat, the entire energy chain of data centers—from input and use to recycling—is improved in efficiency. This solution not only provides two flexible and configurable cooling paths—direct and indirect—to adapt to different needs, but also comprehensively improves the energy utilization rate and environmental friendliness of data centers, providing key technical support for the construction of next-generation green data centers.

[0045] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A carbon dioxide-based data center cooling system for cooling server racks (2) within a large data center (1), wherein the server racks (2) are equipped with high-power AI chips, characterized in that, include: A cooling device (8) is used to produce cryogenic liquid carbon dioxide; at least one storage tank (13, 14) is used to store the liquid carbon dioxide produced by the cooling device (8); a coolant distribution unit (6) is set in the large data center (1) to receive liquid carbon dioxide from the first storage tank (13) and distribute the flow; an inlet manifold (4) is connected to the coolant distribution unit (6) and the cabinet (2) to transport liquid carbon dioxide; an outlet manifold (5) is connected to the cabinet (2) and the coolant distribution unit (6) to collect the carbon dioxide working fluid after absorbing heat; wherein the carbon dioxide working fluid after absorbing heat from the AI ​​chip in the cabinet (2) is returned to the cooling device (8) for circulation.

2. The data center cooling system based on carbon dioxide according to claim 1, characterized in that, The cooling device (8) includes: at least one carbon dioxide compressor (9) for compressing gaseous carbon dioxide; a heat exchanger (10) for receiving high-temperature and high-pressure carbon dioxide gas from the carbon dioxide compressor (9) and condensing it into liquid while releasing the heat of compression; an energy-saving device (11) for recovering the cold energy released by the carbon dioxide working medium before expansion; a first expansion valve (12-1) and a second expansion valve (12-2) for throttling and expanding the high-pressure liquid carbon dioxide from the heat exchanger (10) to transform it into a low-temperature and low-pressure gas-liquid two-phase state; wherein the expanded low-temperature carbon dioxide working medium enters the at least one first storage tank (13) and / or the second storage tank (14).

3. A carbon dioxide-based data center cooling system according to claim 2, characterized in that, It also includes a waste heat recovery power generation unit, which recovers the compression heat carried by the carbon dioxide working fluid flowing through the heat exchanger (10) through the first heat exchanger (21-1) and converts it into electrical energy; the waste heat recovery power generation unit includes a power turbine (27), a generator (28) connected to the power turbine (27), and a cooling device (22) for cooling the carbon dioxide working fluid after it has done work.

4. A carbon dioxide-based data center cooling system according to claim 3, characterized in that, The waste heat recovery power generation unit also includes a booster heater (26), which provides additional heat to the carbon dioxide working fluid of the waste heat recovery power generation unit through a heat exchanger (25). The heat source of the booster heater (26) is selected from solar energy, wind energy or geothermal energy.

5. A carbon dioxide-based data center cooling system according to claim 1, characterized in that, The liquid carbon dioxide produced by the cooling device (8) is directly transported to the main inlet pipe (4) through the coolant distribution unit (6) to directly cool the AI ​​chip in the cabinet (2).

6. A carbon dioxide-based data center cooling system according to claim 5, characterized in that, The cabinet (2) is equipped with a cold plate for cooling the AI ​​chip. The cold plate is either an immersion cold plate or a liquid-cooled cold plate.

7. A carbon dioxide-based data center cooling system according to claim 1, characterized in that, It also includes an independent carbon dioxide circulation loop located outside the cooling device (8). The independent carbon dioxide circulation loop includes: a second storage tank (14); a first coolant circulation pump (19-1) and a third expansion valve (20-1). The inlet of the first coolant circulation pump (19-1) is connected to the second storage tank (14), and the outlet passes through the third expansion valve (20-1), the coolant distribution unit (6), the inlet manifold (4), the cabinet (2) equipped with the AI ​​chip, and the outlet manifold (5) in sequence before returning to the first storage tank (13). The second storage tank (14) or the independent carbon dioxide circulation loop is provided with a heat exchange structure for heat exchange with the cooling device (8) so as to use the cooling capacity provided by the cooling device (8) to cool the carbon dioxide working fluid in the independent carbon dioxide circulation loop.

8. A carbon dioxide-based data center cooling system according to claim 7, characterized in that, The cabinet (2) is equipped with a cold plate for cooling the AI ​​chip. The cold plate is either an immersion cold plate or a liquid-cooled cold plate.

9. A carbon dioxide-based data center cooling system according to any one of claims 1 to 8, characterized in that, The system also includes an indoor heat exchanger (7) and / or a chiller (16) for cooling the interior space of the data center, the cold source of which is supplied by the second storage tank (14).

10. A carbon dioxide-based data center cooling system according to claims 2 to 8, characterized in that, The heat exchanger (10) is also connected to a first heat exchanger (21-1) for supplying the recovered compressed heat to the district heating system.

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