Two-phase immersed fluorine-containing cooling liquid and application thereof

Abstract

The invention discloses a two-phase immersed fluorine-containing cooling liquid, the fluorine-containing cooling liquid comprises a hexafluoropropylene dipolymer and hydrofluoroolefin, the molecular formula of the hexafluoropropylene dipolymer is C6F12, and the molecular formula of the hydrofluoroolefin is C6H2F10, the fluorine-containing cooling liquid not only has good electrical insulation performance, but also has the advantage of high heat transfer coefficient, and the fluorine-containing cooling liquid is suitable for being used as a cooling liquid for a motor vehicle. The fluorine-containing cooling liquid provided by the invention is continuously subjected to the phase change process from the liquid state to the gas state and then from the gas state to the liquid state in the circulating heat dissipation process, the evaporation latent heat of the cooling liquid is fully utilized, and the heat dissipation requirement of a high-power heating element can be met.

Description

Technical Field

[0001] This application relates to the field of fluid heat transfer technology, and particularly to a biphasic immersion fluorinated coolant and its application. Background Art

[0002] Biphasic immersion cooling technology has become a research hotspot due to its advantages such as high heat dissipation performance, convenient maintenance, and low noise. A biphasic immersion cooling system mainly consists of an evaporation section, a condensation section, and a circulation system. The heat-generating device is immersed in an insulating inert coolant and dissipates heat by directly contacting the coolant. This method has advantages such as good heat dissipation performance and low energy consumption, and has become the focus of current research.

[0003] Most of the commonly used biphasic immersion coolants at present are perfluorinated compounds, such as perfluoroamines, perfluoropolyethers, and perfluoroolefins. Although their electrical insulation performance well meets the usage requirements, their heat transfer coefficients are relatively low, mostly around 0.065 W / (m·K), resulting in low heat transfer efficiency and difficulty in meeting the heat dissipation requirements of high heat flux density electronic devices. In addition, perfluoroolefin hexafluoropropylene dimer has the phenomenon of acid reflux during long-term operation, posing a risk of corroding equipment.

[0004] So far, no heat transfer fluid that simultaneously meets the requirements of good electrical insulation performance, high heat transfer coefficient, and good thermal stability has been found. Summary of the Invention

[0005] To solve the problems existing in the prior art, the present invention provides a fluorinated coolant with good electrical insulation performance and relatively high heat transfer coefficient, as well as an application method thereof.

[0006] The specific technical solution of this application is as follows:

[0007] 1. A biphasic immersion fluorinated coolant, wherein the fluorinated coolant contains hexafluoropropylene dimer and hydrofluoroolefin, the molecular formula of the hexafluoropropylene dimer is C6F 12 , and the molecular formula of the hydrofluoroolefin is C6H2F 10 .

[0008] 2. The fluorinated coolant according to item 1, wherein, calculated by mass percentage in the fluorinated coolant, the hexafluoropropylene dimer is 50 - 99%; the hydrofluoroolefin is 1 - 50%.

[0009] 3. The fluorine-containing coolant according to item 1 or 2, wherein the hexafluoropropylene dimer is E-1,1,1,2,3,4,5,5,5-nonafluoro-4-(trifluoromethyl)-2-pentene or a mixture composed of E-1,1,1,2,3,4,5,5,5-nonafluoro-4-(trifluoromethyl)-2-pentene and Z-1,1,1,2,3,4,5,5,5-nonafluoro-4-(trifluoromethyl)-2-pentene, preferably E-1,1,1,2,3,4,5,5,5-nonafluoro-4-(trifluoromethyl)-2-pentene.

[0010] 4. The fluorine-containing coolant according to item 3, wherein when the hexafluoropropylene dimer is a mixture composed of E-1,1,1,2,3,4,5,5,5-nonafluoro-4-(trifluoromethyl)-2-pentene and Z-1,1,1,2,3,4,5,5,5-nonafluoro-4-(trifluoromethyl)-2-pentene, the mass percentage of E-1,1,1,2,3,4,5,5,5-nonafluoro-4-(trifluoromethyl)-2-pentene to Z-1,1,1,2,3,4,5,5,5-nonafluoro-4-(trifluoromethyl)-2-pentene is 80%-99.9%:0.1%-20%.

[0011] 5. The fluorine-containing coolant according to any one of items 1-4, wherein the hydrofluoroolefin is selected from one or more of E-1,1,1,4,5,5,5-heptafluoro-4-(trifluoromethyl)-2-pentene, E-1,1,1,4,4,5,5,6,6,6-decafluoro-2-hexene, E-1,1,1,2,2,5,5,6,6,6-decafluoro-3-hexene, E-1,3,3,4,4,5,5,6,6,6-decafluoro-1-hexene, E-1,3,4,4,5,5,5-heptafluoro-3-(trifluoromethyl)-1-pentene, E-1,3,3,4,5,5,5-heptafluoro-4-(trifluoromethyl)-1-pentene, E-1,4,4,4-tetrafluoro-3,3-bis(trifluoromethyl)-1-butene, preferably selected from one or more of E-1,1,1,4,5,5,5-heptafluoro-4-(trifluoromethyl)-2-pentene, E-1,1,1,4,4,5,5,6,6,6-decafluoro-2-hexene, E-1,1,1,2,2,5,5,6,6,6-decafluoro-3-hexene, E-1,3,3,4,4,5,5,6,6,6-decafluoro-1-hexene, and more preferably E-1,1,1,4,5,5,5-heptafluoro-4-(trifluoromethyl)-2-pentene.

[0012] 6. The fluorine-containing coolant according to any one of items 1-5, wherein the boiling point of the fluorine-containing coolant is 45-55°C, and / or

[0013] the dielectric constant of the fluorine-containing coolant is less than 2.

[0014] 7. Use of the fluorine-containing coolant according to any one of items 1-6 in cooling a server, a heat dissipation system, a communication device, and / or a lighting system.

[0015] 8. The use according to item 7, wherein the cooling is performed on the surface of the server, the heat dissipation system, the communication device, and / or the lighting system in a two-phase form.

[0016] 9. A method for cooling a server, a heat dissipation system, a communication device, and / or a lighting system using the fluorine-containing coolant according to any one of items 1-6, comprising:

[0017] Immersing the server, the heat dissipation system, the communication device, and / or the lighting system in the fluorine-containing coolant for cooling.

[0018] 10. A heat transfer working fluid comprising the fluorine-containing coolant according to any one of items 1-6.

[0019] Effects of the Invention

[0020] The fluorine-containing coolant provided in this application not only has good electrical insulation performance, but also has the advantage of high heat transfer coefficient;

[0021] The fluorine-containing coolant provided in this application has a dielectric constant less than 2 and the capacitance effect is not obvious, so it will not weaken the signal transmission, which is beneficial to maintaining the integrity of the signal. Therefore, computer components and other electronic components can be completely immersed in the fluorine-containing coolant.

[0022] The fluorine-containing coolant provided in this application continuously undergoes a phase change process from liquid to gas and then from gas back to liquid during the cyclic heat dissipation process, making full use of the latent heat of vaporization of the coolant, and can meet the heat dissipation requirements of high-power heating elements. Description of the Drawings

[0023] Figure 1 It is a schematic diagram of a boiling point test measuring device.

[0024] Among them, 1 is a three-necked round-bottom flask; 2 is a test tube; 3 is a rubber stopper; 4 is a measuring thermometer; 5 is an auxiliary thermometer; 6 is a thermometer. Detailed Description of the Invention

[0025] The present application will be described in detail below in conjunction with the described embodiments. Although specific embodiments of the present application are shown, it should be understood that the present application can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided so that the present application can be more thoroughly understood and the scope of the present application can be fully conveyed to those skilled in the art.

[0026] It should be noted that in the description and claims, certain terms are used to refer to specific components. Those skilled in the art should understand that technicians may use different terms to refer to the same component. This description and claims do not distinguish components based on the difference in terms, but rather on the functional differences of the components. As mentioned throughout the description and claims, the terms "comprising" or "including" are open-ended terms and should be interpreted as "including but not limited to". The subsequent description in the specification is the preferred embodiment for implementing the present application. However, the description is for the purpose of the general principles of the specification and is not intended to limit the scope of the present application. The protection scope of the present application shall be subject to that defined by the appended claims.

[0027] The present application provides a biphasic immersion fluorinated coolant. Among them, the fluorinated coolant contains hexafluoropropylene dimer and hydrofluoroolefin. The molecular formula of the hexafluoropropylene dimer is C6F 12 , and the molecular formula of the hydrofluoroolefin is C6H2F 10 .

[0028] The boiling point refers to the temperature at which a pure substance boils under 1 standard atmosphere. Boiling is a violent vaporization phenomenon that occurs simultaneously inside and on the surface of a liquid at a certain temperature. The boiling point is also the temperature at which the saturated vapor pressure of the liquid is equal to the external pressure. The boiling point changes with the change of the external pressure. When the pressure decreases, the boiling point also decreases.

[0029] The fluorinated coolant has characteristics such as chemical stability, non-flammability, non-explosion, and low dielectric constant. It is mainly used in fields such as semiconductors, data centers, chemical industries, aerospace, etc. Among them, the more popular one is for the immersion coolant cooling technology. The immersion coolant cooling technology can not only greatly reduce the energy consumption of data centers, but also further save space, meeting the future development trend of big data centers. Immersion cooling utilizes the high insulation characteristics of the fluorinated coolant to completely immerse the heat-generating components of the server in the fluorinated coolant. Through the direct contact and cyclic heat transfer of the fluorinated coolant, efficient heat dissipation can be achieved for the server, and it is no longer necessary to rely on inefficient methods such as fans and air conditioners for heat dissipation.

[0030] Generally speaking, in biphasic immersion liquid cooling, the coolant continuously undergoes a phase change process from liquid to gas and then from gas back to liquid during the cyclic heat dissipation process. The equipment to be cooled is completely immersed in a closed tank filled with the coolant. The heat generated by the equipment is absorbed by the coolant. After the coolant absorbs heat, its temperature rises. When it reaches the boiling point, it starts to boil and changes from liquid to gas, simultaneously generating a large amount of steam. The steam rises from the liquid and escapes to the upper part of the liquid surface, forming a gas phase region inside the liquid cooling tank. The coolant steam in the gas phase region contacts the water-cooled condenser, and the heat is absorbed by the condenser. The coolant condenses into a liquid and falls back into the container in the form of liquid droplets for recycling, while the heated cooling water in the condenser discharges heat through the circulating cooling water system.

[0031] Also, since the electronic components are immersed in the fluorinated coolant, when the dielectric constant of the fluorinated coolant is less than 2, the high-frequency electronic components and connectors can be immersed in the fluorinated coolant without significant loss of signal integrity, thereby enabling the fluorinated coolant to be used in an immersion cooling system.

[0032] In a specific embodiment of the present application, the fluorinated coolant is composed of hexafluoropropylene dimer and hydrofluoroolefin.

[0033] In a specific embodiment of the present application, based on the mass percentage in the fluorinated coolant, the hexafluoropropylene dimer is 50-99%, and the hydrofluoroolefin is 1-50%.

[0034] In a specific embodiment, the hexafluoropropylene dimer is 60-90%, and the hydrofluoroolefin is 10-40%.

[0035] In a specific embodiment, the hexafluoropropylene dimer is 75-85%, and the hydrofluoroolefin is 15-25%.

[0036] For example, based on the mass percentage in the fluorinated coolant, the hexafluoropropylene dimer can be 50%, 55%, 60%, 65%, 70%, 71%, 72%, 73%, 74%, 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, etc.;

[0037] The hydrofluoroolefin can be 1%, 5%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 30%, 35%, 40%, 45%, 50%, etc.

[0038] In a specific embodiment of the present application, the hexafluoropropylene dimer is E-1,1,1,2,3,4,5,5,5-nonafluoro-4-(trifluoromethyl)-2-pentene or a mixture composed of E-1,1,1,2,3,4,5,5,5-nonafluoro-4-(trifluoromethyl)-2-pentene and Z-1,1,1,2,3,4,5,5,5-nonafluoro-4-(trifluoromethyl)-2-pentene, preferably E-1,1,1,2,3,4,5,5,5-nonafluoro-4-(trifluoromethyl)-2-pentene.

[0039] In a specific embodiment of the present application, when the hexafluoropropylene dimer is a mixture composed of E-1,1,1,2,3,4,5,5,5-nonafluoro-4-(trifluoromethyl)-2-pentene and Z-1,1,1,2,3,4,5,5,5-nonafluoro-4-(trifluoromethyl)-2-pentene, the mass percentage of E-1,1,1,2,3,4,5,5,5-nonafluoro-4-(trifluoromethyl)-2-pentene to Z-1,1,1,2,3,4,5,5,5-nonafluoro-4-(trifluoromethyl)-2-pentene is 80-99.9∶0.1-20, that is, in the mixture composed of E-1,1,1,2,3,4,5,5,5-nonafluoro-4-(trifluoromethyl)-2-pentene and Z-1,1,1,2,3,4,5,5,5-nonafluoro-4-(trifluoromethyl)-2-pentene, E-1,1,1,2,3,4,5,5,5-nonafluoro-4-(trifluoromethyl)-2-pentene accounts for 80%-99.9%, and Z-1,1,1,2,3,4,5,5,5-nonafluoro-4-(trifluoromethyl)-2-pentene accounts for 0.1%-20%.

[0040] For example, in the mixture composed of E-1,1,1,2,3,4,5,5,5-nonafluoro-4-(trifluoromethyl)-2-pentene and Z-1,1,1,2,3,4,5,5,5-nonafluoro-4-(trifluoromethyl)-2-pentene, E-1,1,1,2,3,4,5,5,5-nonafluoro-4-(trifluoromethyl)-2-pentene can be 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99%, 99.1%, 99.2%, 99.3%, 99.4%, 99.5%, 99.6%, 99.7%, 99.8%, 99.9%, etc.;

[0041] Z-1,1,1,2,3,4,5,5,5-nonafluoro-4-(trifluoromethyl)-2-pentene can be 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, etc.

[0042] In a specific embodiment of the present application, the hydrofluoroolefin is selected from one or more of E-1,1,1,4,5,5,5-heptafluoro-4-(trifluoromethyl)-2-pentene, E-1,1,1,4,4,5,5,6,6,6-decafluoro-2-hexene, E-1,1,1,2,2,5,5,6,6,6-decafluoro-3-hexene, E-1,3,3,4,4,5,5,6,6,6-decafluoro-1-hexene, E-1,3,4,4,5,5,5-heptafluoro-3-(trifluoromethyl)-1-pentene, E-1,3,3,4,5,5,5-heptafluoro-4-(trifluoromethyl)-1-pentene, and E-1,4,4,4-tetrafluoro-3,3-bis(trifluoromethyl)-1-butene, preferably selected from one or more of E-1,1,1,4,5,5,5-heptafluoro-4-(trifluoromethyl)-2-pentene, E-1,1,1,4,4,5,5,6,6,6-decafluoro-2-hexene, E-1,1,1,2,2,5,5,6,6,6-decafluoro-3-hexene, and E-1,3,3,4,4,5,5,6,6,6-decafluoro-1-hexene, and more preferably E-1,1,1,4,5,5,5-heptafluoro-4-(trifluoromethyl)-2-pentene.

[0043] In a specific embodiment of the present application, the boiling point of the fluorinated coolant is 45-55 °C, and / or

[0044] the dielectric constant of the fluorinated coolant is less than 2.

[0045] For example, the boiling point of the fluorinated coolant can be 45 °C, 46 °C, 47 °C, 48 °C, 49 °C, 50 °C, 51 °C, 52 °C, 53 °C, 54 °C, 55 °C, etc.;

[0046] the dielectric constant of the fluorinated coolant can be 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, etc.

[0047] When the boiling point of the coolant is relatively low, for the same amount of heat, the coolant can reach the boiling point and boil more quickly, changing from the liquid phase to the gas phase, and at the same time generating a large amount of steam. The steam rises from the liquid and escapes above the liquid surface, forming a gas phase region in the liquid cooling tank, thereby more effectively utilizing the phase change process of the coolant to control the temperature of the equipment to be cooled.

[0048] In the present application, there is no limitation on the method for measuring the boiling point of the fluorinated coolant. It can be measured by conventional methods in the art. For example, it can be measured using GB / T 616-2006 "General Method for the Determination of Boiling Point of Chemical Reagents".

[0049] The present application does not impose any restrictions on the method for measuring the dielectric constant of the fluorine-containing coolant, and it can also be measured by conventional methods in the art. For example, it can be measured by the method disclosed in GB / T 1409-2006.

[0050] The present application does not impose any restrictions on the method for measuring the heat transfer coefficient of the fluorine-containing coolant, and it can also be measured by conventional methods in the art. For example, it can be measured according to the ASTM E1461 standard.

[0051] The present application does not impose any restrictions on the method for measuring the thermal stability of the fluorine-containing coolant, and it can also be measured by conventional methods in the art. For example, it can be measured by the method of ANSI / ASHRAE Standard 97-2007.

[0052] In a specific embodiment of the present application, the fluorine-containing coolant comprises hexafluoropropylene dimer and hydrofluoroolefin, and the molecular formula of the hexafluoropropylene dimer is C6F 12 , and the molecular formula of the hydrofluoroolefin is C6H2F 10In a specific embodiment of the present application, based on the mass percentage in the fluorinated coolant, the hexafluoropropylene dimer is 50-99%, and the hydrofluoroolefin is 1-50%; in a specific embodiment, the hexafluoropropylene dimer is 60-90%, and the hydrofluoroolefin is 10-40%; in a specific embodiment, the hexafluoropropylene dimer is 75-85%, and the hydrofluoroolefin is 15-25%. In a specific embodiment of the present application, the hexafluoropropylene dimer is E-1,1,1,2,3,4,5,5,5-nonafluoro-4-(trifluoromethyl)-2-pentene or a mixture composed of E-1,1,1,2,3,4,5,5,5-nonafluoro-4-(trifluoromethyl)-2-pentene and Z-1,1,1,2,3,4,5,5,5-nonafluoro-4-(trifluoromethyl)-2-pentene, preferably E-1,1,1,2,3,4,5,5,5-nonafluoro-4-(trifluoromethyl)-2-pentene. In a specific embodiment of the present application, when the hexafluoropropylene dimer is a mixture composed of E-1,1,1,2,3,4,5,5,5-nonafluoro-4-(trifluoromethyl)-2-pentene and Z-1,1,1,2,3,4,5,5,5-nonafluoro-4-(trifluoromethyl)-2-pentene, the mass percentage of E-1,1,1,2,3,4,5,5,5-nonafluoro-4-(trifluoromethyl)-2-pentene to Z-1,1,1,2,3,4,5,5,5-nonafluoro-4-(trifluoromethyl)-2-pentene is 80-99.9∶0.1-20. In a specific embodiment of the present application, the hydrofluoroolefin is selected from one or more of E-1,1,1,4,5,5,5-heptafluoro-4-(trifluoromethyl)-2-pentene, E-1,1,1,4,4,5,5,6,6,6-decafluoro-2-hexene, E-1,1,1,2,2,5,5,6,6,6-decafluoro-3-hexene, E-1,3,3,4,4,5,5,6,6,6-decafluoro-1-hexene, E-1,3,4,4,5,5,5-heptafluoro-3-(trifluoromethyl)-1-pentene, E-1,3,3,4,5,5,5-heptafluoro-4-(trifluoromethyl)-1-pentene, and E-1,4,4,4-tetrafluoro-3,3-bis(trifluoromethyl)-1-butene, preferably selected from one or more of E-1,1,1,4,5,5,5-heptafluoro-4-(trifluoromethyl)-2-pentene, E-1,1,1,4,4,5,5,6,6,6-decafluoro-2-hexene, E-1,1,1,2,2,5,5,6,6,6-decafluoro-3-hexene, and E-1,3,3,4,4,5,5,6,6,6-decafluoro-1-hexene, and further preferably E-1,1,1,4,5,5,5-heptafluoro-4-(trifluoromethyl)-2-pentene.In a specific embodiment of the present application, the boiling point of the fluorinated coolant is 45 - 55 °C, and / or the dielectric constant of the fluorinated coolant is less than 2.

[0053] The present application provides the use of the above-mentioned fluorinated coolant in cooling servers, heat dissipation systems, communication devices, and / or lighting systems. In a specific embodiment of the present application, the cooling is performed in a two-phase form, i.e., in the liquid phase and the gas phase, on the surface of the server, heat dissipation system, communication device, and / or lighting system.

[0054] In the present application, the server is mainly a server used in a data center.

[0055] During the application of the fluorinated coolant of the present application, heat transfer is carried out on the cooling surface of an object in a two-phase liquid phase and gas phase form, absorbing the heat of the object, thereby reducing the temperature of the object. At the same time, there is a phase change between the liquid phase and the gas phase. When the phase change occurs, heat exchange can be carried out between the fluorinated coolant and the object.

[0056] The present application provides a method for cooling a server, a heat dissipation system, a communication device, and / or a lighting system with the above-mentioned fluorinated coolant, including:

[0057] Immersing the server, heat dissipation system, communication device, and / or lighting system in the fluorinated coolant for cooling.

[0058] In a specific embodiment of the present application, the server, heat dissipation system, communication device, and / or lighting system are immersed in the fluorinated coolant, and a circulation system and / or a radiator are used for cooling to discharge heat from the fluorinated coolant.

[0059] In a specific embodiment of the present application, computer components (such as CPUs, graphics processors, SSDs, and DDR memories) and other electronic components (including the entire server) can also be immersed in the fluorinated coolant, and a circulation system and / or a radiator are used for cooling to discharge heat from the fluorinated coolant.

[0060] The circulation system can be, for example, a liquid pump, a pipeline, a liquid-liquid heat exchanger, etc.

[0061] The radiator can be a dry cooler (radiator).

[0062] The present application provides a heat transfer working medium that contains the above-mentioned fluorinated coolant.

[0063] Since in immersion liquid cooling technology, the coolant is in direct contact with electronic products, there are strict requirements for the performance of the coolant such as insulation and heat transfer. It is considered that an ideal immersion coolant needs to meet the following technical indicators:

[0064] (1) Insulators have weak performance in storing electrical energy, with a dielectric constant < 2.5 (under the condition of 1 kHz), enabling high-frequency electronic components and connectors to be immersed in the coolant without significant loss of signal integrity.

[0065] (2) Excellent insulation performance, with a dielectric strength > 24 kV (2.54 mm gap);

[0066] (3) The boiling point of the biphasic immersion coolant is generally 20 - 100 °C;

[0067] (4) Excellent heat transfer performance, with a liquid thermal conductivity ≥ 0.06 W / (m·K);

[0068] (5) Good material compatibility, high chemical stability, non-flammable, and no corrosion occurs when contacting electronic components.

[0069] In this application, a hydrofluoroolefin containing vinylidene -CH=CH- is added to hexafluoropropylene dimer. This hydrofluoroolefin can capture the free radical ions generated during the long-term operation of hexafluoropropylene dimer, thereby inhibiting the acid reflux phenomenon of hexafluoropropylene dimer during operation and significantly improving the thermal stability of hexafluoropropylene dimer.

[0070] The hydrofluoroolefins added in this application all have a dielectric constant less than 2. In particular, the hydrofluoroolefin with a hydrogen-to-fluorine atom number ratio equal to 1 / 5 is non-flammable, and its mixture with hexafluoropropylene dimer in any proportion is also non-flammable. In addition, the dielectric constants of the fluorinated coolants in this application are all less than 2.0, and even less than 1.9, enabling high-frequency electronic components and connectors to be immersed in the fluid without significant loss of signal integrity, fully meeting the requirements for fluorinated heat transfer fluids used in immersion cooling systems. At the same time, during the continuous phase change process of the fluorinated coolant provided in this application, the latent heat of vaporization of the coolant is fully utilized, which can meet the heat dissipation requirements of high-power heating elements.

[0071] The fluorinated coolant of the present invention can be obtained by uniformly mixing the components according to the designed component ratio under stirring conditions. Each component can be purchased or synthesized according to the methods reported in the existing literature.

[0072] Examples

[0073] The following further details this application in combination with examples, but does not limit the scope of this application.

[0074] (I) Boiling point test

[0075] (1) Standard: GB / T 616 - 2006 "General Method for the Determination of Boiling Point of Chemical Reagents"

[0076] (2) Principle of the method: When the temperature of a liquid rises, its vapor pressure increases accordingly. When the vapor pressure of the liquid equals the atmospheric pressure, the liquid starts to boil. Under standard conditions (1013.25 hPa, 0 °C), the boiling temperature of the liquid is the boiling point of that liquid.

[0077] (3) The test device is as Figure 1 shown.

[0078] Among them, a three-neck round-bottom flask, a test tube and a measuring thermometer are connected with a rubber stopper. The lower end of the measuring thermometer is 20 mm away from the liquid level in the test tube. An auxiliary thermometer is attached to the measuring thermometer so that its mercury bulb is in the middle of the mercury column of the measuring thermometer exposed outside the rubber stopper. About half of the volume of the flask is filled with silicone oil.

[0079] (a) Three-neck round-bottom flask: The effective volume of the three-neck round-bottom flask is 500 mL.

[0080] (b) Test tube: The test tube is 190 mm - 200 mm long, and there is a side hole with a diameter of 2 mm about 15 mm away from the test tube mouth.

[0081] (c) Rubber stopper: The outside of the rubber stopper has an air outlet groove.

[0082] (d) Measuring thermometer and auxiliary thermometer: The measuring thermometer shall comply with the provisions of JJG 130, and a total immersion mercury thermometer with a graduation value of 0.1 °C shall be selected. The indication range is suitable for the boiling point temperature of the sample to be measured. The auxiliary thermometer is used to correct the mercury column of the measuring thermometer exposed outside the stopper during the distillation process. The temperature range of the auxiliary thermometer is 0 °C - 50 °C, and the graduation value is 1 °C.

[0083] (e) Barometer: The barometer shall comply with the provisions of JJG 272.

[0084] (4) Determination method: Measure an appropriate amount of the sample and inject it into the test tube, with its liquid level slightly lower than the liquid level of the silicone oil in the flask. Heat it. When the temperature rises to a certain value and remains unchanged for a considerable period of time, this temperature is the boiling point of the sample to be measured. At the same time, record the room temperature and the atmospheric pressure.

[0085] (II) Electrical insulation performance test

[0086] (1) Dielectric constant test method: The test is carried out in accordance with the method of GB / T 1409-2006.

[0087] (2) Dielectric strength test method: The test is carried out in accordance with the method of GB T 5654-1985 under the conditions of a voltage frequency of 1000 Hz and an electrode plate spacing of 2.54 mm.

[0088] (III) Heat transfer coefficient test

[0089] (1) Standard: ASTM E1461

[0090] Test method for determining the thermal diffusivity of solids by the flash method (laser flash method). A high-intensity energy pulse irradiates a small and thin specimen for a short time. The energy of the pulse is absorbed by the front surface of the specimen and the resulting temperature rise of the back surface (temperature self-recording curve) is recorded. The value of the thermal diffusivity is calculated from the thickness of the specimen and the time required for the temperature rise of the back surface to reach a certain ratio of the maximum value.

[0091] (2) Instrument model: ASTM E1461 laser thermal conductivity meter LFA46

[0092] Test method: Laser flash method (LFA)

[0093] Test standard: ASTM E1461

[0094] Temperature range: -100 °C to 500 °C

[0095] Heating rate: up to 50 K / min

[0096] Thermal diffusivity: 0.01 mm 2 / s - 1000 mm 2 / s

[0097] Thermal conductivity: 0.1 W / (m·K) - 2000 W / (m·K)

[0098] Accuracy: Thermal diffusivity: + / -3%; Specific heat: + / -5% (standard sample)

[0099] Repeatability: Thermal diffusivity: + / -2%; Specific heat: + / -3%

[0100] (3) Method principle:

[0101] The laser flash method uses a pulsed laser to irradiate one surface of the specimen, and then monitors the temperature change of the other surface through an infrared thermometer. The actually measured data is the thermal diffusivity α(T) of the sample. It is also necessary to know the specific heat Cp(T) and density ρ(T) of the specimen. Finally, the thermal conductivity is calculated through the formula, that is, λ(T) = α(T) * Cp(T) * ρ(T).

[0102] (a) LFA467: Directly measures the thermal diffusivity in the horizontal direction. The specific heat needs to be obtained by the sapphire (α-aluminum oxide 99.99%) method and the thermal conductivity is calculated; In-plane thermal diffusivity testing is suitable for high-conductivity ultra-thin samples and not suitable for low-conductivity samples.

[0103] (4) Thermal stability test

[0104] The thermal stability of the fluorinated coolant was evaluated by testing according to the method of ANSI / ASHRAE Standard 97-2007 in a sealed glass tube. The fluorinated coolant sample was placed in a glass tube with a metal (such as Fe, Al, Cu, stainless steel 316, Fe is used in this application) impregnated specimen having a structure commonly used in liquid cooling devices. The tube was sealed and heated in an oven at 175 °C for 32 days. The decomposition of the fluorinated coolant after 32 days of aging was quantified based on the measured fluoride ion concentration (in parts per million (ppm)).

[0105] Experimental Example 1

[0106] E-1,1,1,2,3,4,5,5,5-nonafluoro-4-(trifluoromethyl)-2-pentene and E-1,1,1,4,5,5,5-heptafluoro-4-(trifluoromethyl)-2-pentene were mixed at a mass percentage of 0.1%:99.9% to obtain a fluorinated coolant, and the boiling point, electrical insulation performance, and heat transfer coefficient were tested respectively. The test results are shown in Table 1.

[0107] Experimental Example 2

[0108] The same operation as in Experimental Example 1 was carried out, except that the mass percentage of E-1,1,1,2,3,4,5,5,5-nonafluoro-4-(trifluoromethyl)-2-pentene and E-1,1,1,4,5,5,5-heptafluoro-4-(trifluoromethyl)-2-pentene was modified to 1%:99%, and the test results are shown in Table 1.

[0109] Experimental Example 3

[0110] The same operation as in Experimental Example 1 was carried out, except that the mass percentage of E-1,1,1,2,3,4,5,5,5-nonafluoro-4-(trifluoromethyl)-2-pentene and E-1,1,1,4,5,5,5-heptafluoro-4-(trifluoromethyl)-2-pentene was modified to 10%:90%, and the test results are shown in Table 1.

[0111] Experimental Example 4

[0112] The same operation as in Experimental Example 1 was carried out, except that the mass percentage of E-1,1,1,2,3,4,5,5,5-nonafluoro-4-(trifluoromethyl)-2-pentene and E-1,1,1,4,5,5,5-heptafluoro-4-(trifluoromethyl)-2-pentene was modified to 20%:80%, and the test results are shown in Table 1.

[0113] Experimental Example 5

[0114] The same operations as in Experimental Example 1 were carried out, except that the mass percentage content of E-1,1,1,2,3,4,5,5,5-nonafluoro-4-(trifluoromethyl)-2-pentene and E-1,1,1,4,5,5,5-heptafluoro-4-(trifluoromethyl)-2-pentene was changed to 30%∶70%. The test results are shown in Table 1.

[0115] Experimental Example 6

[0116] The same operations as in Experimental Example 1 were carried out, except that the mass percentage content of E-1,1,1,2,3,4,5,5,5-nonafluoro-4-(trifluoromethyl)-2-pentene and E-1,1,1,4,5,5,5-heptafluoro-4-(trifluoromethyl)-2-pentene was changed to 40%∶60%. The test results are shown in Table 1.

[0117] Experimental Example 7

[0118] The same operations as in Experimental Example 1 were carried out, except that the mass percentage content of E-1,1,1,2,3,4,5,5,5-nonafluoro-4-(trifluoromethyl)-2-pentene and E-1,1,1,4,5,5,5-heptafluoro-4-(trifluoromethyl)-2-pentene was changed to 50%∶50%. The test results are shown in Table 1.

[0119] Experimental Example 8

[0120] The same operations as in Experimental Example 1 were carried out, except that the mass percentage content of E-1,1,1,2,3,4,5,5,5-nonafluoro-4-(trifluoromethyl)-2-pentene and E-1,1,1,4,5,5,5-heptafluoro-4-(trifluoromethyl)-2-pentene was changed to 60%∶40%. The test results are shown in Table 1.

[0121] Experimental Example 9

[0122] The same operations as in Experimental Example 1 were carried out, except that the mass percentage content of E-1,1,1,2,3,4,5,5,5-nonafluoro-4-(trifluoromethyl)-2-pentene and E-1,1,1,4,5,5,5-heptafluoro-4-(trifluoromethyl)-2-pentene was changed to 70%∶30%. The test results are shown in Table 1.

[0123] Experimental Example 10

[0124] The same operations as in Experimental Example 1 were carried out, except that the mass percentage content of E-1,1,1,2,3,4,5,5,5-nonafluoro-4-(trifluoromethyl)-2-pentene and E-1,1,1,4,5,5,5-heptafluoro-4-(trifluoromethyl)-2-pentene was changed to 80%∶20%. The test results are shown in Table 1.

[0125] Experimental Example 11

[0126] The same operations as in Experimental Example 1 were carried out, except that the mass percentage contents of E-1,1,1,2,3,4,5,5,5-nonafluoro-4-(trifluoromethyl)-2-pentene and E-1,1,1,4,5,5,5-heptafluoro-4-(trifluoromethyl)-2-pentene were changed to 85%∶15%, and the test results are shown in Table 1.

[0127] Experimental Example 12

[0128] The same operations as in Experimental Example 1 were carried out, except that the mass percentage contents of E-1,1,1,2,3,4,5,5,5-nonafluoro-4-(trifluoromethyl)-2-pentene and E-1,1,1,4,5,5,5-heptafluoro-4-(trifluoromethyl)-2-pentene were changed to 90%∶10%, and the test results are shown in Table 1.

[0129] Experimental Example 13

[0130] The same operations as in Experimental Example 1 were carried out, except that the mass percentage contents of E-1,1,1,2,3,4,5,5,5-nonafluoro-4-(trifluoromethyl)-2-pentene and E-1,1,1,4,5,5,5-heptafluoro-4-(trifluoromethyl)-2-pentene were changed to 99%∶1%, and the test results are shown in Table 1.

[0131] Experimental Example 14

[0132] The same operations as in Experimental Example 1 were carried out, except that the mass percentage contents of E-1,1,1,2,3,4,5,5,5-nonafluoro-4-(trifluoromethyl)-2-pentene and E-1,1,1,4,5,5,5-heptafluoro-4-(trifluoromethyl)-2-pentene were changed to 99.9%∶0.1%, and the test results are shown in Table 1.

[0133] Experimental Example 15

[0134] The same operations as in Experimental Example 8 were carried out, except that the E-1,1,1,2,3,4,5,5,5-nonafluoro-4-(trifluoromethyl)-2-pentene was replaced with an equal mass of a mixture composed of E-1,1,1,2,3,4,5,5,5-nonafluoro-4-(trifluoromethyl)-2-pentene and Z-1,1,1,2,3,4,5,5,5-nonafluoro-4-(trifluoromethyl)-2-pentene according to the mass percentage contents of 99.9% and 0.1%, and the test results are shown in Table 1.

[0135] Experimental Example 16

[0136] The same operations as in Experimental Example 8 were carried out, except that the E-1,1,1,2,3,4,5,5,5-nonafluoro-4-(trifluoromethyl)-2-pentene was replaced with an equal mass of a mixture composed of E-1,1,1,2,3,4,5,5,5-nonafluoro-4-(trifluoromethyl)-2-pentene and Z-1,1,1,2,3,4,5,5,5-nonafluoro-4-(trifluoromethyl)-2-pentene in a mass percentage of 96% and 4%, respectively. The test results are shown in Table 1.

[0137] Experimental Example 17

[0138] The same operations as in Experimental Example 8 were carried out, except that the E-1,1,1,2,3,4,5,5,5-nonafluoro-4-(trifluoromethyl)-2-pentene was replaced with an equal mass of a mixture composed of E-1,1,1,2,3,4,5,5,5-nonafluoro-4-(trifluoromethyl)-2-pentene and Z-1,1,1,2,3,4,5,5,5-nonafluoro-4-(trifluoromethyl)-2-pentene in a mass percentage of 90% and 10%, respectively. The test results are shown in Table 1.

[0139] Experimental Example 18

[0140] The same operations as in Experimental Example 8 were carried out, except that the E-1,1,1,2,3,4,5,5,5-nonafluoro-4-(trifluoromethyl)-2-pentene was replaced with an equal mass of a mixture composed of E-1,1,1,2,3,4,5,5,5-nonafluoro-4-(trifluoromethyl)-2-pentene and Z-1,1,1,2,3,4,5,5,5-nonafluoro-4-(trifluoromethyl)-2-pentene in a mass percentage of 80% and 20%, respectively. The test results are shown in Table 1.

[0141] Experimental Example 19

[0142] The same operations as in Experimental Example 8 were carried out, except that the E-1,1,1,4,5,5,5-heptafluoro-4-(trifluoromethyl)-2-pentene was replaced with an equal mass of E-1,1,1,4,4,5,5,6,6,6-decafluoro-2-hexene. The test results are shown in Table 1.

[0143] Experimental Example 20

[0144] The same operations as in Experimental Example 8 were carried out, except that the E-1,1,1,4,5,5,5-heptafluoro-4-(trifluoromethyl)-2-pentene was replaced with an equal mass of E-1,1,1,2,2,5,5,6,6,6-decafluoro-3-hexene. The test results are shown in Table 1.

[0145] Experimental Example 21

[0146] The same operations as in Experimental Example 8 were carried out, except that E-1,3,3,4,4,5,5,6,6,6-decafluoro-1-hexene with the same mass was used to replace E-1,1,1,4,5,5,5-heptafluoro-4-(trifluoromethyl)-2-pentene, and the test results are shown in Table 1.

[0147] Comparative Example 1

[0148] E-1,1,1,2,3,4,5,5,5-nonafluoro-4-(trifluoromethyl)-2-pentene was respectively tested for boiling point, electrical insulation performance and heat transfer coefficient, and the test results are shown in Table 1.

[0149] Comparative Example 2

[0150] Z-1,1,1,2,3,4,5,5,5-nonafluoro-4-(trifluoromethyl)-2-pentene was respectively tested for boiling point, electrical insulation performance and heat transfer coefficient, and the test results are shown in Table 1.

[0151] Comparative Example 3

[0152] The same operations as in Experimental Example 8 were carried out, except that Z-1,1,1,4,4,5,5,5-octafluoro-2-pentene with the same mass was used to replace E-1,1,1,4,5,5,5-heptafluoro-4-(trifluoromethyl)-2-pentene, and the test results are shown in Table 1.

[0153] Table 1 Performance of coolants with different compositions

[0154]

[0155]

[0156]

[0157] The results in Table 1 show that by adding hydrofluoroolefins, not only the excellent electrical insulation performance (greater than or equal to 40 kV) of the fluorinated fluid is maintained, but also the heat transfer coefficient is significantly improved, the heat transfer efficiency is increased, and at the same time the thermal stability is improved, so that the fluoride ion concentration is far less than 100 ppm, meeting the use requirements. Moreover, in this application, the proportion of the added hydrofluoroolefin is controlled, so that the production cost of the coolant in this application is controlled while ensuring the cooling effect.

[0158] As can be seen from Table 1, for Experimental Examples 1-14, with the increase in the addition ratio of hydrofluoroolefins, the heat transfer performance of the fluorinated coolant increases. However, correspondingly, the dielectric strength and dielectric constant decrease, and the boiling point continuously increases. However, due to the relatively high production cost of hydrofluoroolefins, therefore, using a mixture composed of a certain proportion of hexafluoropropylene dimer and hydrofluoroolefins can achieve relatively good performance. For example, in Experimental Example 8 or Experimental Example 9, while the thermal stability is far less than 100 ppm, the thermal conductivity and dielectric strength are both relatively good, and the production cost is greatly reduced.

[0159] Comparing Experimental Example 8 with Experimental Examples 15-18, different hexafluoropropylene dimers were used in Experimental Examples 15-18, but the dielectric strength of the coolant decreased slightly. The result of using E-1,1,1,2,3,4,5,5,5-nonafluoro-4-(trifluoromethyl)-2-pentene is relatively good.

[0160] Comparing Experimental Example 8 with Experimental Examples 19-21, different hydrofluoroolefins were used in Experimental Examples 19-21. Using E-1,1,1,4,5,5,5-heptafluoro-4-(trifluoromethyl)-2-pentene as the hydrofluoroolefin gives relatively good results.

[0161] Comparative Example 1 and Comparative Example 2 only used a single hexafluoropropylene dimer. Although the dielectric strength increased slightly, the thermal conductivity and dielectric constant decreased significantly, and the thermal stability was far inferior to the mixture composed of a certain proportion of hexafluoropropylene dimer and hydrofluoroolefins provided in this application.

[0162] Comparative Example 3 used Z-1,1,1,4,4,5,5,5-octafluoro-2-pentene and hexafluoropropylene dimer to form the coolant. Compared with Example 8, their thermal stability performances are almost the same. Although the heat transfer performance of Comparative Example 3 is better, its dielectric strength is too low, and the dielectric constant is very high, far greater than 2, not meeting the usage requirements that the dielectric constant of the immersion fluorinated coolant is less than 2.5 or even less than 2. Therefore, this application uses hydrofluoroolefins with special structures and properties (heat transfer, electrical insulation, thermal stability, etc.) to achieve excellent comprehensive effects of immersion liquid cooling, rather than any random hydrofluoroolefin can meet the usage requirements of this application.

[0163] Therefore, the biphasic immersion fluorinated coolant provided in this application has excellent heat transfer efficiency and good thermal stability, and can ensure that the data signal transmitted in the fluid remains intact. Those skilled in the art can flexibly select coolants with different components and different composition ratios according to needs to achieve a balance among factors such as cooling effect, signal transmission, and cost control.

[0164] The above are only the preferred embodiments of the present application, and are not intended to limit the present application in any other form. Any person skilled in the art may use the technical content disclosed above to make changes or modifications into equivalent embodiments with equivalent changes. However, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present application without departing from the technical solution content of the present application still fall within the protection scope of the technical solution of the present application.

Claims

1. A biphasic immersion fluorinated coolant, wherein, The fluorine-containing coolant contains hexafluoropropylene dimer and hydrofluoroolefin. The molecular formula of the hexafluoropropylene dimer is C6F 12 , and the molecular formula of the hydrofluoroolefin is C6H2F 10 .

2. The fluorine-containing coolant according to claim 1, wherein, The hexafluoropropylene dimer is 50-99% by mass percentage in the fluorine-containing coolant; The hydrofluoroolefin is 1-50%.

3. The fluorine-containing coolant according to claim 1 or 2, wherein the hexafluoropropylene dimer is E-1,1,1,2,3,4,5,5,5-nonafluoro-4-(trifluoromethyl)-2-pentene or a mixture composed of E-1,1,1,2,3,4,5,5,5-nonafluoro-4-(trifluoromethyl)-2-pentene and Z-1,1,1,2,3,4,5,5,5-nonafluoro-4-(trifluoromethyl)-2-pentene, preferably E-1,1,1,2,3,4,5,5,5-nonafluoro-4-(trifluoromethyl)-2-pentene.

4. The fluorine-containing coolant according to claim 3, wherein, When the hexafluoropropylene dimer is a mixture composed of E-1,1,1,2,3,4,5,5,5-nonafluoro-4-(trifluoromethyl)-2-pentene and Z-1,1,1,2,3,4,5,5,5-nonafluoro-4-(trifluoromethyl)-2-pentene, the mass percentage of E-1,1,1,2,3,4,5,5,5-nonafluoro-4-(trifluoromethyl)-2-pentene and Z-1,1,1,2,3,4,5,5,5-nonafluoro-4-(trifluoromethyl)-2-pentene is 80%-99.9%:0.1%-20%.

5. The fluorine-containing coolant according to any one of claims 1-4, wherein, The hydrofluoroolefin is selected from one or more of E-1,1,1,4,5,5,5-heptafluoro-4-(trifluoromethyl)-2-pentene, E-1,1,1,4,4,5,5,6,6,6-decafluoro-2-hexene, E-1,1,1,2,2,5,5,6,6,6-decafluoro-3-hexene, E-1,3,3,4,4,5,5,6,6,6-decafluoro-1-hexene, E-1,3,4,4,5,5,5-heptafluoro-3-(trifluoromethyl)-1-pentene, E-1,3,3,4,5,5,5-heptafluoro-4-(trifluoromethyl)-1-pentene, E-1,4,4,4-tetrafluoro-3,3-bis(trifluoromethyl)-1-butene, preferably selected from one or more of E-1,1,1,4,5,5,5-heptafluoro-4-(trifluoromethyl)-2-pentene, E-1,1,1,4,4,5,5,6,6,6-decafluoro-2-hexene, E-1,1,1,2,2,5,5,6,6,6-decafluoro-3-hexene, E-1,3,3,4,4,5,5,6,6,6-decafluoro-1-hexene, and more preferably E-1,1,1,4,5,5,5-heptafluoro-4-(trifluoromethyl)-2-pentene.

6. The fluorine-containing coolant according to any one of claims 1-5, wherein, The boiling point of the fluorine-containing coolant is 45-55 °C, and / or The dielectric constant of the fluorine-containing coolant is less than 2.

7. Use of the fluorine-containing coolant according to any one of claims 1-6 in cooling a server, a heat dissipation system, a communication device, and / or a lighting system.

8. The use according to claim 7, wherein The cooling is to cool the surface of a server, a heat dissipation system, a communication device, and / or a lighting system in a two-phase form.

9. A method for cooling a server, a heat dissipation system, a communication device, and / or a lighting system using the fluorine-containing coolant according to any one of claims 1-6, comprising: Immersing the server, the heat dissipation system, the communication device, and / or the lighting system in the fluorine-containing coolant for cooling.

10. A heat transfer working fluid, which comprises the fluorine-containing coolant according to any one of claims 1-6.

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