An immersion liquid cooling system and cooling method

Abstract

This invention relates to the field of cooling technology, and in particular to an immersion liquid cooling system and method. An immersion liquid cooling system includes: a cooling tank and a coolant and a heating element disposed within the cooling tank; a coolant circulation system is connected to the cooling tank; the system is characterized by an aeration system connected to the cooling tank, which pumps a non-corrosive gas that is insoluble or sparingly soluble in the coolant and does not chemically react with the coolant, and an exhaust pipe for the gas is provided at the top of the cooling tank. This invention allows gas to be introduced into the liquid cooling system, creating a gas-liquid two-phase flow, enhancing heat exchange, resulting in high cooling efficiency and safety.

Description

Technical Field

[0001] This invention relates to the field of cooling technology, and in particular to an immersion liquid cooling system and cooling method. Background Technology

[0002] In recent years, with increasingly stringent national requirements for energy conservation and emission reduction in newly built data centers, and given that air conditioning is the primary energy consumer in data centers, there has been a greater demand for green and energy-efficient data centers. While traditional air cooling has become the main cooling method due to its low cost and ease of maintenance, it suffers from drawbacks such as low air heat transfer coefficient, poor heat transfer performance, and high cooling energy consumption. Moreover, it requires a large amount of space to house air conditioners, racks, and air supply channels, resulting in large space occupation, low deployment density, and being detrimental to energy conservation and environmental protection. Therefore, liquid cooling has become a new cooling method for data centers.

[0003] Compared to air cooling, immersion cooling transfers heat entirely from the heat source via the coolant. Because it's in direct contact with the heat source, the liquid flow is easier to control, resulting in significantly higher efficiency and a higher computational density per unit volume compared to air cooling. Furthermore, unlike natural air cooling, which is subject to stringent requirements regarding ambient temperature, humidity, and air corrosiveness, immersion cooling technology is much more flexible in terms of environmental conditions and deployment. The reusable nature of immersion cooling systems also eliminates the need for redesigning the cooling system during upgrades, shortening system deployment time.

[0004] The current drawback of immersion cooling is that it cannot effectively solve the problem of rapid heat dissipation in areas of high heat flux density in heat-generating components, which can easily lead to local overheating and thermal runaway. Furthermore, if fluorinated liquids are used as coolants for immersion cooling of heat-generating components, such as the hydrofluoroethers, fluorinated hydrocarbons, and fluorinated olefin oligomers disclosed in patents US20210395213A1, US20200178414A1, and CN113717698A, there are drawbacks such as high coolant prices, the ozone-depleting properties of the coolant leading to a greenhouse effect, and difficulties in maintaining the cooling system.

[0005] In immersion cooling, hydrocarbon compounds are often used as coolants, such as straight-chain alpha-olefins (LAO) and Fischer-Tropsch hydrocarbons disclosed in patents WO2022076207A1, CN115340850A, and CN115349010A. These coolants are inexpensive, and low-carbon hydrocarbons have low kinematic viscosity and good cooling effect, but their low flash point and poor dielectric properties can easily lead to accidents. High-carbon hydrocarbons have high flash points, strong dielectric properties, and good safety, but their kinematic viscosity is relatively higher, resulting in poorer heat transfer capacity and inferior cooling effect compared to low-carbon hydrocarbons. However, clause 5.4 of the current standard YD / T 3982-2021 stipulates that the flash point of the immersion coolant should be greater than 150℃, or a non-flammable liquid (fluorinated liquid) with no flash point should be used. Therefore, due to the inherently low flash point of the coolant, the choice of coolant type for immersion cooling is limited, and coolants with better heat transfer performance are difficult to apply to immersion cooling.

[0006] CN102760920B proposes a liquid nitrogen cooling method and apparatus for automotive power battery packs. This method utilizes the large amount of heat absorbed during the vaporization of liquid nitrogen to cool the power battery pack, achieving a better cooling effect, extending the battery pack's lifespan, and avoiding safety hazards caused by excessively high battery temperatures. However, nitrogen's specific heat capacity is lower than that of fluorinated liquids and hydrocarbon compounds. Cooling the battery pack is achieved by continuously introducing liquid nitrogen and utilizing its phase change heat absorption. This solution consumes even more liquid nitrogen for cooling heat-generating components that require long-term operation, such as data centers and computer servers, necessitating frequent replacement of liquid nitrogen tanks and increasing the operating cost of the cooling system. Summary of the Invention

[0007] To address the aforementioned issues, this invention proposes introducing gas into the cooling tank of an immersion liquid cooling system. The gas-liquid two-phase flow enhances heat exchange, thereby improving the cooling effect of the coolant on the heat-generating components. Simultaneously, the gas is a flame-retardant or inert gas, preventing combustion of the coolant due to its low flash point, and avoiding short circuits or corrosion of the heat-generating components. Even if thermal runaway occurs in the heat-generating components, it can prevent serious accidents such as fires and explosions, thus ensuring the safety and reliability of the immersion liquid cooling system. This system is particularly suitable for large, multi-unit parallel immersion liquid cooling systems in data centers, computer servers, and other applications.

[0008] In a first aspect, the present invention proposes an immersion liquid cooling system, comprising: a cooling tank and a coolant and a heating element disposed within the cooling tank; a coolant circulation system connected to the cooling tank, and an aeration system connected to the cooling tank, the aeration system being connected to the cooling tank to pump a non-corrosive gas that is insoluble or sparingly soluble in the coolant and does not chemically react with the coolant, and an exhaust pipe for the gas being disposed at the top of the cooling tank; the aeration system includes a gas storage tank for storing the gas, the gas storage tank being connected to a gas channel, the portion of the gas channel connected to the cooling tank being covered by the coolant. The coolant is a single-phase coolant, defined as a coolant that does not undergo a phase change during the absorption and transfer of heat generated by the heating element.

[0009] Furthermore, under low-temperature conditions where the coolant temperature in the cooling tank does not exceed the critical temperature, the gas flow rate connected to the aeration system and the cooling tank is maintained at 10~50 mL / min, and the pressure in the cooling tank is controlled at 1~5 bar; under high-temperature conditions where the coolant temperature in the cooling tank exceeds the critical temperature, the gas flow rate connected to the aeration system and the cooling tank is maintained at 50~1000 mL / min, and the pressure in the cooling tank is controlled at 1~5 bar; preferably, the critical temperature is 30~45℃, and more preferably, the critical temperature is 30~40℃.

[0010] Furthermore, the coolant circulation system includes a heat exchanger and coolant piping. The two ends of the coolant piping are positioned on a cooling tank to form a circulating loop. A one-way pump is installed on the coolant piping to draw coolant from the cooling tank. A section of the coolant piping is located within the heat exchanger, which is equipped with a shut-off valve to regulate the flow rate of the coolant in the circulating pipe. Preferably, the heat exchanger contains cooling water, which is circulating water that completely submerges this section of the coolant piping. The temperature of the cooling water is maintained below 20 degrees Celsius.

[0011] Furthermore, the gas channel is also equipped with a gas pressure regulating device and a flow detection device. The exhaust pipe is connected to the cooling tank, and the exhaust pipe is also equipped with an exhaust valve. Preferably, before connecting the gas channel to the cooling tank, a multi-channel valve can be used to divide it into two or more branches, and the cooling tank is connected through multiple branches.

[0012] The gas in the gas storage tank is a non-corrosive gas that is insoluble or sparingly soluble in the coolant and does not chemically react with the coolant. Preferably, the gas is a flame-retardant gas or an inert gas. More preferably, the gas is nitrogen or carbon dioxide. Furthermore, the gas in the gas storage tank is a compressed gas obtained by compression, and the pressure of the compressed gas is 50 to 500 bar.

[0013] Furthermore, the gas storage tank can be replaced by a corresponding gas generating device, such as a pressure swing adsorption (PSA) nitrogen generator, which can replace the nitrogen storage tank.

[0014] Furthermore, the gas channel is a stainless steel capillary tube. Preferably, the stainless steel capillary tube is made of 201, 304 or 316L, with an outer diameter of 1.0~18.0 mm and a wall thickness of 0.1~2 mm.

[0015] The gas pressure regulating device is a gas pressure reducing valve, a gas proportional valve, or both connected in series. Preferably, the gas pressure regulating device is a gas pressure reducing valve and a gas proportional valve connected in series.

[0016] The flow detection device is a flow meter or a velocity meter. Preferably, the flow detection device is a flow meter. More preferably, the flow meter is a glass rotor flow meter.

[0017] In one or more embodiments, the immersion liquid cooling system has at least two sets of cooling tanks side by side, and the gas passage is connected to the side and / or bottom of the gas storage tank and the cooling tank respectively through a multi-channel valve to form at least two or more branches.

[0018] Furthermore, the cooling tank is a fully enclosed shell with an internal space, and a cooling tank cover that can be opened or closed is provided on the top. The heating element and the coolant are disposed within the internal space of the cooling tank, and the heating element is in contact with the coolant. Preferably, a support is also provided within the internal space of the cooling tank to support and fix the heating element in the cooling tank, and the support material is preferably aluminum.

[0019] Furthermore, the cooling tank is equipped with temperature and pressure sensors to detect the temperature of the coolant and the pressure inside the cooling tank. The temperature and pressure sensors transmit the collected temperature and pressure signals to the control unit, which first converts the transmitted temperature and pressure signals into digital data and then displays them on its own display. The display can be integrated with the control unit or designed wirelessly or via a wired connection.

[0020] Preferably, a data acquisition card is electrically connected to the temperature sensor and the pressure sensor respectively, and the data acquisition card is then electrically connected to the computer. The data acquisition card converts the sensing resistance of the temperature sensor and the pressure sensor into temperature and pressure data, respectively, and outputs them to the computer.

[0021] Furthermore, coolant is defined as a dielectric oil-like fluid with low electrical conductivity, low flammability, and low freezing point, including API-III base oil, API-IV base oil, API-V base oil, silicone oil, or fluorinated fluid, etc.

[0022] Furthermore, the API-III base oil is preferably an isoparaffin compound with 8 to 50 carbon atoms, such as the ICSSYN® series of isoparaffin dewaxed base oil products ICSSYN®2, ICSSYN®3, ICSSYN®4 and ICSSYN®6, and the SINOPURE® series of isoparaffin products 1016H, 1620H, 2028H and 2835, which are synthesized from coal-to-syngas by Fehling-Tropsch synthesis.

[0023] Furthermore, the API-IV base oil is preferably a polyalphaolefin (PAO) with 8 to 50 carbon atoms, such as the Synfluid® series of fully synthetic base oils Synfluid® PAO 2, Synfluid® PAO 2.5, Synfluid® PAO 4, Synfluid® PAO 5 and Synfluid® PAO 6, and ApaCool from ApaCool Technology Co., Ltd. TM 1. ApaCool TM 1.5, ApaCool TM 1.7, ApaCool TM 2, AapCool TM 2.5, ApaSyn TM 3.5, ApaSyn TM 4 with ApaSyn TM Level 6.

[0024] Furthermore, the API-V base oil is preferably an alkylated aromatic hydrocarbon with 8 to 50 carbon atoms, a synthetic ester or synthetic ether with 8 to 50 carbon atoms, such as Synestic. TM 5. and DowSyn® AN5, etc.

[0025] Furthermore, the silicone oil includes: Shin-Etsu KF-96 series silicone fluids KF-96A-1cs, KF-96A-1.5cs, KF-96A-2cs, KF-96A-5cs, KF-96A-6cs, KF-96A-10cs and KF-96A-20cs, etc.

[0026] Furthermore, the fluorinated liquid includes: 3M Fluorinert TM A series of fluorinated coolants, including liquid FC-40, FC-70, FC-72, and FC-770.

[0027] Preferably, the coolant comprises API-IV or API-V base oils with 8 to 30 carbon atoms, and silicone oils with a kinematic viscosity of less than 10 cst at 25°C, such as KF-96A-1.5cs, KF-96A-2cs, KF-96A-5cs, KF-96A-6cs, and KF-96A-10cs. More preferably, the coolant comprises API-IV or API-V base oils with 8 to 20 carbon atoms, and silicone oils with a kinematic viscosity of less than 5 cst at 25°C, such as KF-96A-1.5cs, KF-96A-2cs, and KF-96A-5cs.

[0028] Preferably, the coolant meets the requirements of section 5.1-5.3 of the application performance of contact (insulating) coolant in standard YD / T 3982-2021.

[0029] Preferably, the pour point of the coolant is below -40°C, and more preferably, the pour point of the coolant is below -50°C.

[0030] Furthermore, the heat-generating component may include one or more computer and network devices, electronic devices, optoelectronic devices, battery cells, or electrical units.

[0031] The computer and network equipment includes computer servers, computer server clusters, Internet servers, data centers, 5G base stations, cloud computing servers, and computer game equipment, etc. Preferably, the data center is a data center with an operating frequency greater than 3GHz. More preferably, the data center may include equipment or part of the data center for centrally managed computing resources and related support systems, as well as modular components that provide the data center together with other modules.

[0032] Electronic devices include central processing units, microprocessors, motherboards, graphics cards, memory, semiconductor wafers used to manufacture semiconductor devices, semiconductor dies, packaged or unpackaged semiconductor devices, multi-chip modules, and circuit boards, etc.

[0033] Optoelectronic devices are defined as functional devices or semiconductor wafers made using the photo-to-electric conversion effect to convert light energy into electrical energy or electrical energy into light energy. These optoelectronic devices include light-emitting diodes, laser diodes, solar panels, and photodetectors, etc.

[0034] A battery cell is defined as an electrochemical reactor that converts chemical energy into electrical energy. The electrochemical reactor includes various types of electrochemical batteries, specifically including fuel cells, power batteries, sodium-ion batteries, and lithium-ion batteries.

[0035] Electrical units include power distribution switchgear, power transformers, and charging piles.

[0036] Secondly, the present invention proposes a cooling method using the above-mentioned immersion liquid cooling system. This method adopts a direct cooling method, which is a method of cooling the heating component by directly immersing the heating component with coolant. Specifically, it includes: placing the heating component in a cooling tank, and immersing part or all of the heating component with coolant.

[0037] Under low-temperature conditions where the coolant temperature in the cooling tank does not exceed the critical temperature, the gas pressure regulating device is turned on and adjusted to maintain a gas flow rate of 10~50 mL / min in the gas channel connected to the cooling tank, and the pressure in the cooling tank is controlled at 1~5 bar. The purpose of introducing gas under low-temperature conditions is to provide an inert and flame-retardant atmosphere for the internal space of the cooling tank, preventing the coolant from igniting due to its low flash point.

[0038] Under high-temperature conditions where the coolant temperature in the cooling tank exceeds the critical temperature, the gas pressure regulating device is adjusted to maintain a gas flow rate of 50~1000 mL / min in the gas channel connected to the cooling tank, and the pressure in the cooling tank is controlled at 1~5 bar. The purpose of introducing gas under high-temperature conditions is not only to provide an inert and flame-retardant atmosphere, but also to create a gas-liquid two-phase flow state to improve the heat transfer effect of the coolant and quickly transfer the heat generated by the heat-generating components.

[0039] The critical temperature is 30~45℃, preferably 30~40℃.

[0040] The beneficial effects of this invention are:

[0041] 1. An air supply system is installed on the basis of the immersion liquid cooling system. The air supply system delivers gases that are immiscible with the coolant to the coolant through one or more gas channels. During the heat exchange process, a two-phase flow state of gas and liquid is formed, thereby enhancing the heat exchange effect. The gas delivery speed can also be adjusted according to the temperature of the coolant itself. In low-temperature conditions, the gas delivery speed is reduced to reduce system consumption. In high-temperature conditions, the gas delivery speed is increased to create turbulence in the coolant, increase the disturbance of the coolant, and thus facilitate the heat transfer of the coolant.

[0042] 2. The gas supply system delivers gas to multiple parallel cooling tanks through gas channels and a gas pressure regulating device. This enables the simultaneous improvement of cooling effect for multiple parallel cooling systems. Compared with setting disturbance devices or jet devices in the cooling system, the technical solution proposed in this invention, which uses gas to form a gas-liquid two-phase flow state to improve the cooling effect, saves equipment, is simpler and more practical, and is more economical. It is especially suitable for cooling large, multi-group heat-generating components such as data center servers.

[0043] 3. The gas in the charging system is an inert or flame-retardant gas, ensuring that the heating components and coolant in the cooling tank are in an atmosphere of inert or flame-retardant gas. This prevents the coolant from igniting due to its low flash point or short-circuiting of the heating components. Even if thermal runaway occurs in the heating components, it can prevent serious accidents such as fires and explosions, thus ensuring the safety and reliability of the immersion liquid cooling system. It also expands the range of coolant options; low flash point coolants such as KF-96A-1cs (flash point 37℃), KF-96A-1.5cs (flash point 64℃), KF-96A-2cs (flash point 88℃), 1016H (flash point 46℃), 1620H (flash point 66℃), and 2028H (flash point 95℃) can also be used in immersion liquid cooling systems. Attached Figure Description

[0044] Figure 1 This is a schematic diagram of the structure of Embodiment 1 of the present invention.

[0045] Figure 2 This is a schematic diagram of the structure of Embodiment 2 of the present invention.

[0046] Figure 3 This is a schematic diagram of the structure of Embodiment 3 of the present invention.

[0047] Figure 4-6 The graph shows the temperature variation of a lithium battery with discharge time under different discharge rates and nitrogen flow rates. Detailed Implementation

[0048] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0049] In the description of this application, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0050] It should also be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. Example

[0051] like Figure 1 As shown, an immersion liquid cooling system includes: a cooling tank 1 and a coolant 2 and a heating element 3 disposed within the cooling tank 1; a coolant circulation system is provided on one side of the cooling tank 1, the coolant circulation system including a heat exchanger 4 and a coolant pipeline 5, the two ends of the coolant pipeline 5 are disposed on the cooling tank 1 to form a circulation loop, a one-way pump 6 is provided on the coolant pipeline 5 to draw coolant 2 from the cooling tank 1, and one section of the coolant pipeline 5 is disposed within the heat exchanger 4; a gas storage tank 7 is provided on the other side of the cooling tank 1, the gas in the gas storage tank 7 is nitrogen, the gas storage tank 7 pumps nitrogen into the coolant 2 through a gas channel 8, the gas channel 8 is connected to the bottom or side of the cooling tank 1, and a gas pressure regulating device 9 is provided on the gas channel 8; an exhaust pipe 10 is provided on the upper part or top surface of the side of the cooling tank 1.

[0052] The heat exchanger 4 is equipped with cooling water, which is a circulating water that can completely submerge the section of coolant pipe 5. The temperature of the cooling water is maintained below 20 degrees Celsius. The gas channel 8 is equipped with a flow detection device 11, which is located at the rear end of the gas pressure regulating device 9. The gas channel 8 is a stainless steel capillary tube made of 316L stainless steel, with an outer diameter of 8.5 mm and a wall thickness of 0.4 mm.

[0053] The system is also equipped with detection sensors, including a temperature sensor 121 and a pressure sensor 122. The temperature sensor 121 is located on the side of the cooling tank 1 and is used to detect the temperature of the coolant 2. The pressure sensor 122 is located on the top of the cooling tank 1 and is in communication with the gas inside the cooling tank 1. The system is also equipped with multiple valves, including a pressure relief valve 131 located on the exhaust pipe 10 and a shut-off valve 132 located on the coolant pipeline 5.

[0054] Among them, temperature sensor 121 and pressure sensor 122 are surface-mount temperature sensor and surface-mount pressure sensor, respectively, which are electrically connected to NI data acquisition card (from National Instruments, USA). The NI data acquisition card is then electrically connected to a computer. The data acquisition card converts the sensing resistance of the surface-mount temperature sensor and surface-mount pressure sensor into temperature and pressure data and outputs them to the LabVIEW program on the computer, thereby monitoring the temperature change of the coolant and the pressure change in the cooling tank.

[0055] The top of the cooling tank 1 is provided with a cover 14. The cover 14 and the body of the cooling tank 1 are designed to be lifted or opened. A sealing mechanism is provided between the cover 14 and the body of the cooling tank 1. When the cover 14 is closed, the cooling tank 1 remains sealed.

[0056] The heating element is a lithium-ion battery pack consisting of six lithium batteries and a support frame. Each lithium battery is a 3.62V-2150mAh Samsung-ICR-18650-22P type, sourced from Samsung Corporation of South Korea. It is cylindrical in shape, with dimensions of 18mm in diameter and 65mm in height. Typical capacity: 2150mAh (0.2C, 2.75V discharge). Charging voltage: 4.2V±0.05V. Nominal voltage: 3.62V (1C discharge). Charging method: CC-CV (current-limited constant voltage). Standard charging current: 1075mA. Maximum charging current: 2150mA. Maximum discharge current: 10A (continuous discharge). Discharge cutoff voltage: 2.75V. Maximum battery weight: 44.5g. The charging and discharging process is controlled using a BT-2018 P battery testing system (Hubei Lanbo New Energy Equipment Co., Ltd.).

[0057] The immersion liquid cooling system has a cooling tank volume of 960mL and dimensions of 120×80×100 mm. The gas passage is a 316L stainless steel capillary tube with an outer diameter of 8.5mm and a wall thickness of 0.4mm. The gas pressure regulating device is a gas pressure reducing valve and a gas proportional valve connected in series. The flow detection device is a glass rotor flow meter. The gas storage tank contains 40L of compressed nitrogen with a built-in pressure of 200bar.

[0058] The coolant used in Example 1 was a C6 α-olefin trimer (18C) prepared by hydrogenation saturation based on a metallocene catalyst system, and its relevant properties are shown in the table below.

[0059]

[0060] 700 mL of the aforementioned heat transfer fluid was added to an immersion cooling bath. The ICR-18650-22P lithium-ion battery was placed in the immersion cooling bath and immersed in the coolant for cooling. For charge / discharge testing, the battery pack was charged at a rate of 0.5C using a constant current constant voltage (CC-CV) method and discharged to the cutoff voltage under constant current.

[0061] When the lithium-ion battery is discharged at 1.5C, 2C and 3C rates, the flow rate of the coolant circulating through the circulation pipeline is set to a fixed value of 70 mL / min. The gas pressure regulating device is adjusted to maintain the nitrogen flow rate in the gas channel connected to the cooling tank at 10~1000 mL / min, and the pressure relief valve is adjusted to control the pressure in the cooling tank at 1.5 bar.

[0062] The battery temperature was recorded starting from 30°C using a calibrated (±0.2°C error) Agilent 34970A temperature data acquisition instrument and an Omegar K-type thermocouple. The K-type thermocouple was placed in the middle of the lithium battery to record temperature changes.

[0063] Among them, under different discharge rates and nitrogen flow rates, the change of lithium battery temperature with discharge time is as follows: Figure 4-6 As shown, introducing nitrogen gas into the coolant to form a gas-liquid two-phase flow can better control the temperature of the heating components. When lithium-ion batteries are discharged at 1.5C, 2C, and 3C rates, introducing different flow rates of nitrogen gas can achieve better temperature control. Figure 4 , 5 It can be seen that a higher nitrogen flow rate results in better temperature control of the lithium battery. Figure 6 It can be seen that the effect of increasing the nitrogen flow rate on the temperature control of the lithium battery tends to stabilize after a certain point. Therefore, the immersion liquid cooling system of Example 1, based on immersion cooling, introduces nitrogen gas, which is incompatible with the coolant. During the heat exchange process, a two-phase flow state of gas and liquid is formed, thereby quickly removing the heat generated by the heat-generating components and keeping them operating within the optimal temperature range. Simultaneously, the nitrogen gas also provides an inert and flame-retardant atmosphere to the internal space of the immersion cooling tank. The immersion liquid cooling system of Example 1 has the advantages of strong heat exchange capacity and high safety performance. Example

[0064] like Figure 2 As shown, this embodiment adopts the same method as Embodiment 1, but with multiple branches at the end of the gas channel 8. These branches are connected to the main gas channel 8 via multi-channel valves. The branches of the gas channel 8 are respectively located at the bottom or side of components experiencing severe heat generation. The branches and the gas channel 8 are made of the same material. The gas pumped from these branches can precisely handle various high-heat areas, accelerating the flow of coolant and significantly improving cooling efficiency. The gas storage tank contains 40L of compressed nitrogen at a built-in 200bar pressure, and the coolant is a C6 α-olefin trimer (18C) prepared based on a metallocene catalyst system and hydrogenation saturation. Example

[0065] like Figure 3 As shown, this embodiment adopts the scheme of Embodiment 1 above, while connecting two cooling tanks in parallel, with the coolant at their bottoms circulating between them; the coolant circulation is as follows: coolant is drawn from one cooling tank, and after heat exchange, it is injected into the other cooling tank; the gas in the gas storage tank is divided into two streams through a multi-channel valve, and after the gas is divided, each stream passes through a pressure reducing device and a flow detection device before being pumped into its respective cooling tank. The two cooling tanks have their own exhaust pipes for exhaust; both cooling tanks are equipped with temperature and pressure sensors. The gas storage tank contains 40L of compressed nitrogen gas at a built-in 200bar pressure, and the coolant is a C6 α-olefin trimer (18C) prepared based on a metallocene catalyst system and hydrogenation saturation.

[0066] The operating principle of this invention is to introduce gas into a basic liquid cooling system, which can perform normal heat exchange. The gas is a flame-retardant gas or an inert gas. These gases agitate the coolant in the cooling tank. After the coolant exchanges heat with the heat-generating components, this part of the coolant may remain in the vicinity for a long time. The pumping in of gas will push this coolant into the heat exchange cycle, thereby improving the cooling efficiency.

[0067] The foregoing description of embodiments of the present invention, through which those skilled in the art are able to implement or use the present invention, will be readily apparent to those skilled in the art. Various modifications to these embodiments will be readily apparent to those skilled in the art. The general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novelty disclosed herein.

Claims

1. An immersion liquid cooling system, comprising: The cooling tank (1) and the coolant (2) and heating element (3) installed in the cooling tank (1); a coolant circulation system is connected to the cooling tank (1), characterized in that an air filling system is connected to the cooling tank (1), the air filling system is connected to the cooling tank (1) to pump non-corrosive, insoluble or sparingly soluble gas into the coolant (2) and does not chemically react with the coolant, and an exhaust pipe (10) for the gas is installed at the top of the cooling tank (1); the air filling system includes a gas storage tank (7) for storing gas, the gas storage tank (7) is connected to a gas channel (8), the part of the gas channel (8) connected to the cooling tank (1) is covered by the coolant (2), and the coolant (2) is a single-phase coolant; The gas is a flame-retardant gas or an inert gas; the coolant is defined as a dielectric oil-like fluid with low electrical conductivity, low flammability and low freezing point, including API-III base oil, API-IV base oil, API-V base oil or silicone oil. Under low-temperature conditions where the temperature of the coolant in the cooling tank (1) does not exceed the critical temperature, the gas flow rate of the gas supply system connected to the cooling tank (1) is maintained at 10~50 mL / min, and the pressure in the cooling tank (1) is controlled at 1~5 bar; under high-temperature conditions where the temperature of the coolant in the cooling tank (1) exceeds the critical temperature, the gas flow rate of the gas supply system connected to the cooling tank (1) is maintained at 50~1000 mL / min, and the pressure in the cooling tank (1) is controlled at 1~5 bar; the critical temperature is 30~45℃.

2. The immersion liquid cooling system of claim 1, wherein: The critical temperature is 30~40℃.

3. The immersion liquid cooling system of claim 1, wherein: The coolant circulation system includes a heat exchanger (4) and a coolant pipeline (5). The two ends of the coolant pipeline (5) are set on the cooling tank (1) to form a circulation loop. A one-way pump (6) is provided on the coolant pipeline (5) to draw coolant (2) from the cooling tank (1). One section of the coolant pipeline (5) is set in the heat exchanger (4). The heat exchanger (4) is equipped with a shut-off valve (132).

4. The immersion liquid cooling system according to claim 3, characterized in that: The heat exchanger (4) is equipped with cooling water, which is circulating water. The cooling water can completely submerge this section of the coolant pipeline (5), and the temperature of the cooling water is kept below 20 degrees Celsius.

5. The immersion liquid cooling system according to claim 1, characterized in that: The gas passage (8) is also equipped with a gas pressure regulating device (9) and a flow detection device (11). The exhaust pipe (10) is connected to the cooling tank (1). The exhaust pipe (10) is also equipped with an exhaust valve (131).

6. The immersion liquid cooling system according to claim 5, characterized in that: The gas passage (8) is divided into two or more branches by a multi-channel valve before being connected to the cooling tank (1), and the cooling tank (1) is connected through the multi-channel valve.

7. The immersion liquid cooling system according to claim 1, characterized in that: The gas is either nitrogen or carbon dioxide.

8. The immersion liquid cooling system according to claim 1, characterized in that: The gas in the gas storage tank (7) is compressed gas obtained by compression, and the pressure of the compressed gas is 50~500 bar.

9. The immersion liquid cooling system according to claim 1, characterized in that: The gas storage tank (7) is replaced by a corresponding gas generating device.

10. The immersion liquid cooling system according to claim 5, characterized in that: The gas channel is a stainless steel capillary tube.

11. The immersion liquid cooling system according to claim 10, characterized in that: The stainless steel capillary tube is made of 201, 304 or 316L, with an outer diameter of 1.0~18.0 mm and a wall thickness of 0.1~2 mm.

12. The immersion liquid cooling system according to claim 5, characterized in that: The gas pressure regulating device is a gas pressure reducing valve, a gas proportional valve, or both connected in series.

13. The immersion liquid cooling system according to claim 5, characterized in that: The flow detection device is a flow rate meter.

14. The immersion liquid cooling system according to claim 5, characterized in that: The flow detection device is a flow meter.

15. The immersion liquid cooling system according to claim 14, characterized in that: The flow meter is a glass rotor flow meter.

16. The immersion liquid cooling system according to claim 1, characterized in that: The immersion liquid cooling system has at least two sets of cooling tanks in parallel. The gas channel (8) has multiple branches at its end. The multiple branches are connected to the gas channel (8) through a multi-channel valve. The branches of the gas channel (8) are respectively located at the bottom or side of the component that is generating severe heat.

17. The immersion liquid cooling system according to claim 1, characterized in that: The cooling tank (1) is also equipped with a support frame to support and fix the heat-generating components in the cooling tank.

18. The immersion liquid cooling system according to claim 17, characterized in that: The support structure is made of aluminum.

19. The immersion liquid cooling system according to claim 1, characterized in that: The cooling tank (1) is also equipped with a temperature sensor (121) and a pressure sensor (122) to detect the temperature of the coolant (2) and the pressure inside the cooling tank (1); the temperature sensor (121) and the pressure sensor (122) transmit the collected temperature and pressure signals to the control unit respectively. The control unit first converts the transmitted temperature and pressure signals into digital data and then displays them on its own display. The display and control unit are designed as an integrated unit.

20. The immersion liquid cooling system according to claim 19, characterized in that: The display and control unit are designed to be wireless or wired.

21. The immersion liquid cooling system according to claim 19, characterized in that: A data acquisition card is electrically connected to the temperature sensor and the pressure sensor respectively. The data acquisition card is then electrically connected to the computer. The data acquisition card converts the sensing resistance of the temperature sensor and the pressure sensor into temperature and pressure data, respectively, and outputs them to the computer.

22. The immersion liquid cooling system according to claim 1, characterized in that: The API-III base oils are isoparaffinic compounds with 8 to 50 carbon atoms.

23. The immersion liquid cooling system according to claim 1, characterized in that: The API-III base oils are CCSYN® series isomerized dewaxing base oil products ICCSYN®2, ICCSYN®3, ICCSYN®4 and ICCSYN®6, and SINOPURE® series isomerized alkane products 1016H, 1620H, 2028H and 2835, which are synthesized from coal-to-syngas by Fehler synthesis.

24. The immersion liquid cooling system according to claim 1, characterized in that: The API-IV base oil is a polyalphaolefin (PAO) with 8 to 50 carbon atoms.

25. The immersion liquid cooling system according to claim 1, characterized in that: The API-IV base oils are Synfluid® series fully synthetic base oils: Synfluid® PAO 2, Synfluid® PAO 2.5, Synfluid® PAO 4, Synfluid® PAO 5 and Synfluid® PAO 6.

26. The immersion liquid cooling system according to claim 1, characterized in that: The API-V base oil is an alkylated aromatic hydrocarbon with 8 to 50 carbon atoms, a synthetic ester or a synthetic ether with 8 to 50 carbon atoms.

27. The immersion liquid cooling system according to claim 1, characterized in that: The API Group V base oil Synesstic TM 5 with Dow AN5.

28. The immersion liquid cooling system according to claim 1, characterized in that: The silicone oils include: Shin-Etsu KF-96 series silicone fluids KF-96A-1cs, KF-96A-1.5cs, KF-96A-2cs, KF-96A-5cs, KF-96A-6cs, KF-96A-10cs and KF-96A-20cs.

29. The immersion liquid cooling system according to claim 1, characterized in that: The coolant includes API-IV base oils and API-V base oils with 8 to 30 carbon atoms, as well as silicone oils with a kinematic viscosity of less than 10 cst at 25°C.

30. The immersion liquid cooling system according to claim 1, characterized in that: The coolants include KF-96A-1.5cs, KF-96A-2cs, KF-96A-5cs, KF-96A-6cs and KF-96A-10cs.

31. The immersion liquid cooling system according to claim 1, characterized in that: The coolant is an API-IV base oil with 8 to 20 carbon atoms, an API-V base oil, and a silicone oil with a kinematic viscosity of less than 5 cst at 25°C.

32. The immersion liquid cooling system according to claim 1, characterized in that: The coolant is KF-96A-1.5cs, KF-96A-2cs, or KF-96A-5cs.

33. The immersion liquid cooling system according to claim 1, characterized in that: The coolant meets the requirements of section 5.1-5.3 of the application performance of contact (insulating) coolant in standard YD / T 3982-2021.

34. The immersion liquid cooling system according to claim 1, characterized in that: The coolant has a pour point below -40°C.

35. The immersion liquid cooling system according to claim 1, characterized in that: The coolant has a pour point below -50°C.

36. The immersion liquid cooling system according to claim 1, characterized in that: Heat-generating components include one or more computer and network devices or optoelectronic devices.

37. The immersion liquid cooling system according to claim 1, characterized in that: Heat-generating components include electronic devices.

38. The immersion liquid cooling system according to claim 37, characterized in that: Electronic devices include one of the following: central processing unit, microprocessor, motherboard, graphics card, memory, semiconductor wafer, semiconductor die, packaged or unpackaged semiconductor device, and multi-chip module.

39. The immersion liquid cooling system according to claim 36, characterized in that: Optoelectronic devices are defined as functional devices or semiconductor wafers made using the photo-to-electric conversion effect to convert light energy into electrical energy or electrical energy into light energy. These optoelectronic devices include one of the following: light-emitting diodes, laser diodes, solar panels, and photodetectors.

40. The immersion liquid cooling system according to claim 1, characterized in that: The heat-generating components include the battery cells.

41. The immersion liquid cooling system according to claim 40, characterized in that: A battery cell is defined as an electrochemical reactor that converts chemical energy into electrical energy, and the electrochemical reactor includes an electrochemical cell.

42. The immersion liquid cooling system according to claim 40, characterized in that: The battery unit includes one of the following: a fuel cell and a power battery.

43. The immersion liquid cooling system according to claim 40, characterized in that: The battery cells include sodium-ion batteries.

44. The immersion liquid cooling system according to claim 40, characterized in that: The battery cells include: lithium-ion batteries.

45. The immersion liquid cooling system according to claim 1, characterized in that: The heat-generating components include electrical units.

46. ​​The immersion liquid cooling system according to claim 45, characterized in that: The electrical unit includes one of the following: power distribution switchgear, power transformer, and charging pile.

47. A cooling method for an immersion liquid cooling system, characterized in that, The method employs the immersion liquid cooling system described in any one of claims 1, 3-46. Under low-temperature conditions where the coolant temperature in the cooling tank does not exceed the critical temperature, the gas pressure regulating device is activated and adjusted to maintain a gas flow rate of 10-50 mL / min in the gas channel connected to the cooling tank, and the pressure in the cooling tank is controlled at 1-5 bar. Under high-temperature conditions where the coolant temperature in the cooling tank exceeds the critical temperature, the gas pressure regulating device is adjusted to maintain a gas flow rate of 50-1000 mL / min in the gas channel connected to the cooling tank, and the pressure in the cooling tank is controlled at 1-5 bar. The critical temperature is 30-45°C.

48. A cooling method for an immersion liquid cooling system, characterized in that, The method employs the immersion liquid cooling system described in claim 2. Under low-temperature conditions where the coolant temperature in the cooling tank does not exceed the critical temperature, the gas pressure regulating device is activated and adjusted to maintain a gas flow rate of 10-50 mL / min in the gas channel connected to the cooling tank, and the pressure in the cooling tank is controlled at 1-5 bar. Under high-temperature conditions where the coolant temperature in the cooling tank exceeds the critical temperature, the gas pressure regulating device is adjusted to maintain a gas flow rate of 50-1000 mL / min in the gas channel connected to the cooling tank, and the pressure in the cooling tank is controlled at 1-5 bar. The critical temperature is 30-40°C.

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