Preparation method of decafluoropentene cooling medium for phase change cooling

Abstract

The invention provides a preparation method of a decafluoropentene cooling medium for phase change cooling, and belongs to the technical field of cooling. The decafluoropentene is subjected to multi-component blending and stability optimization, so that the decafluoropentene has excellent thermal stability, heat transfer efficiency and material compatibility in thermal management application of electronic devices, energy systems and the like. The prepared cooling medium has high phase change latent heat, a wide operating temperature range and excellent cycling stability, and the performance of a cooling system is remarkably improved.

Description

Technical Field

[0001] The present invention relates to the field of cooling technology, and in particular to a preparation method of a decafluoropentene cooling medium for phase change cooling. Background Art

[0002] With the rapid development of information technology, the heat density of data processing devices, communication devices, and electronic products has been continuously increasing, which results in a large amount of heat generated during the operation of these devices. Especially in high-power density systems such as servers, supercomputer centers, and new energy batteries, the generated heat often exceeds the range that can be effectively dissipated by traditional air-cooling technologies. Long-term overheating will not only affect the stability and service life of the devices but also reduce the operating efficiency of the devices. Therefore, how to effectively manage and dissipate the heat generated by these devices has become an important challenge in the fields of modern electronic devices, energy systems, etc.

[0003] In traditional cooling technologies, air-cooling systems and liquid-cooling systems are two main heat dissipation methods. Air-cooling systems are widely used in electronic devices and data centers. They take away heat through air convection and have the advantages of simple structure and low cost. However, with the continuous increase in device power, the heat dissipation capacity of air-cooling systems gradually fails to meet the needs of high-density devices. Especially in devices such as high-performance servers, GPUs, and FPGAs, the heat dissipation efficiency of air-cooling gradually becomes inadequate. Moreover, the energy efficiency of air-cooling systems is relatively low, often resulting in high energy consumption and increasing the operating cost of the devices.

[0004] To solve the limitations of air-cooling heat dissipation, liquid-cooling heat dissipation systems have emerged. Liquid-cooling systems take away heat from heat-generating components through liquid cooling media. Compared with air-cooling, liquid-cooling has higher thermal conductivity and better heat dissipation effect. Liquid-cooling heat dissipation systems are mainly divided into two categories: indirect-contact liquid-cooling and direct-immersion liquid-cooling. In an indirect-contact liquid-cooling system, the coolant exchanges heat indirectly with electronic components through a heat exchanger, while in a direct-immersion liquid-cooling system, the heat-generating components are completely immersed in the coolant, and heat is directly taken away by the liquid. This method is particularly prominent in the heat dissipation of high-density heat sources and has great application prospects especially in applications such as high-performance servers, supercomputer data centers, and laser devices.

[0005] Direct-immersion liquid-cooling is divided into single-phase liquid-cooling and two-phase liquid-cooling. The coolant in a single-phase liquid-cooling system is always in a liquid state, and heat exchange mainly depends on the fluidity of the liquid during the circulation process; while a two-phase liquid-cooling system utilizes the phase change characteristics of the coolant. The liquid undergoes a phase change (liquid changes to gas) during the heat absorption process, enabling heat to be quickly taken away in a shorter time, thus greatly improving the heat exchange efficiency. Since the coolant in a two-phase liquid-cooling system undergoes a phase change, the heat transfer efficiency is higher than that of single-phase liquid-cooling, so it shows more excellent performance in applications with high heat flux density.

[0006] However, the coolants currently applied in two-phase liquid cooling systems are mainly some short-chain fluorides, such as FC-72, Novec-649, HFE-7100, etc. Although they perform well in terms of heat conduction and chemical stability, there are still some deficiencies. First, there is still room for improvement in the cooling effect of these fluorides. Especially in high-temperature environments, the cooling effect is easily affected. Second, the production and use of some fluorides will have a certain impact on the environment, especially in terms of the greenhouse effect and ozone depletion. Although their GWP (Global Warming Potential) and ODP (Ozone Depletion Potential) are relatively low, there are still environmental protection risks. Summary of the Invention

[0007] In view of the above market demands, the present invention provides a preparation method of a decafluoropentene cooling medium for phase change cooling. The method uses decafluoropentene as the main component and prepares the cooling medium through multi-component blending and interface regulation methods, solving the problems of poor stability and uneven heat transfer in the application of its monomer, and improving its application efficiency in the thermal management system.

[0008] The specific solution is as follows:

[0009] A preparation method of a decafluoropentene cooling medium for phase change cooling, characterized by comprising the following steps:

[0010] (1) By mass, 90-95 parts of decafluoropentene raw material are purified and dehydrated under an inert atmosphere. The dehydration operation temperature is 20-30 °C, and the dehydration time is 24 hours;

[0011] (2) The purified decafluoropentene is mixed with 5-15 parts of a stabilizing aid and stirred for 10-15 minutes;

[0012] (3) 0.02-0.2 part of an interface modifier is added, and ultrasonic equipment is used for dispersion. The dispersion time is 10-30 minutes;

[0013] (4) The mixed solution obtained in step (3) is stirred at room temperature for 1-2 hours until the solution is uniform, and a stable cooling medium is obtained.

[0014] In one embodiment, the inert atmosphere is selected from one of nitrogen or argon.

[0015] In one embodiment, the stabilizing aid is selected from one of perfluorotributyl ether or perfluorohexane.

[0016] In one embodiment, the preparation method of the interface modifier is:

[0017] K1: Raw material preparation and mixing: By weight, add 36 - 72 parts of perfluorohexyl propylene, 10 - 20 parts of 1,9 - nonanedithiol, 1 - 3 parts of 5 - mercapto - 1 - methyltetrazole (CAS No.: 13183 - 79 - 4), 0.01 - 0.1 part of benzoin dimethyl ether, and 150 - 200 parts of tetrahydrofuran into the reaction vessel, and introduce nitrogen into the reaction vessel for 15 - 60 minutes to remove oxygen;

[0018] K2: Photo - initiated addition reaction: Turn on the ultraviolet lamp with a wavelength of 365 nm and stir the reaction at room temperature for 1 - 3 hours;

[0019] K3: Product separation and purification: After the reaction is completed, perform vacuum distillation on the reaction mixture to remove the solvent.

[0020] In one embodiment, the dispersion power of the ultrasonic device is 50 - 200 W.

[0021] In one embodiment, the normal - temperature stirring temperature is 15 - 30 °C.

[0022] The phase - change cooling system includes a coolant tank, a condenser, a pressure monitor, and a temperature monitor.

[0023] The decafluoropentene cooling medium is applied to the cooling system of electronic devices, thermal management systems, or new - energy vehicles.

[0024] Beneficial effects:

[0025] 1) Significantly improve the cooling efficiency: High - purity decafluoropentene, as the main cooling component, utilizes its excellent phase - change latent heat and suitable phase - change temperature to rapidly absorb a large amount of heat on the surface of the heating element, convert it into a gaseous state, and take away the thermal energy, significantly enhancing the heat - dissipation capacity.

[0026] 2) Enhance the thermal stability and cycle life of the system: The stabilizing agent and decafluoropentene form a uniform blend system, reducing the evaporation pressure difference and making the condensation more efficient, thus maintaining stable heat - transfer performance during long - term use.

[0027] 3) Improve the wettability with the device interface and enhance the heat - transfer efficiency: The sulfur - containing structure and fluoroalkyl group in the interface modifier can self - assemble on the device surface to form a low - surface - energy wetting layer, reducing local dry spots and improving the phase - change heat - exchange efficiency; at the same time, the perfluoroolefin reacts with thiols to generate a stable, non - ionic fluorinated modifier, which can not only enhance the dispersion stability but also does not affect the dielectric constant and chemical stability. Specific embodiments

[0028] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Apparently, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0029] Example 1

[0030] A preparation method of a decafluoropentene cooling medium for phase change cooling is as follows:

[0031] 1) Dehydration treatment:

[0032] Place 92 kg of decafluoropentene raw material in a reaction vessel equipped with a stirring device, and perform dehydration treatment at 25 °C for 24 hours under a nitrogen atmosphere to remove trace moisture.

[0033] 2) Mixing of stabilizing additives:

[0034] Mix the dehydrated decafluoropentene with 8 kg of perfluorotributyl ether, and stir at room temperature for 12 minutes to make it uniform.

[0035] 3) Adding an interfacial modifier and dispersion:

[0036] Add 0.02 kg of interfacial modifier, and use an ultrasonic device for dispersion, with a power of 100 W and a dispersion time of 15 minutes.

[0037] Preparation method of the interfacial modifier:

[0038] Step K1: Raw material preparation and mixing

[0039] Add the following components by weight to the reaction vessel:

[0040] Perfluorohexyl acrylene: 600 g

[0041] 1,9-Nonanedithiol: 150 g

[0042] 5-Mercapto-1-methyltetrazole (CAS No.: 13183-79-4): 20 g

[0043] Benzoin dimethyl ether: 0.5 g

[0044] Tetrahydrofuran: 1800 g

[0045] Introduce nitrogen into the reaction vessel for 30 minutes to completely displace oxygen.

[0046] Step K2: Photoinitiated addition reaction

[0047] Turn on the ultraviolet lamp with an opening wavelength of 365 nm and stir the reaction for 2 hours at room temperature (25 °C). The system gradually becomes clear.

[0048] Step K3: Product separation and purification

[0049] After the reaction is completed, remove tetrahydrofuran by vacuum distillation to obtain a transparent light yellow oily product, which is the interfacial modifier.

[0050] 4) Homogeneous mixing:

[0051] Stir the mixed solution in step (3) at 20 °C for 1.5 hours to obtain a stable and transparent cooling medium.

[0052] Example 2

[0053] 1) Dehydration treatment:

[0054] Under the protection of argon, dehydrate 90 kg of perfluoropentene raw material in an environment of 30 °C for 24 hours to remove residual moisture.

[0055] 2) Stable additive mixing:

[0056] Add 10 kg of perfluorohexane to the dehydrated perfluoropentene above and stir at room temperature for 10 minutes to form a preliminary mixture.

[0057] 3) Add interfacial modifier and disperse:

[0058] Add 0.08 kg of interfacial modifier, use an ultrasonic device with a power of 200 W, and disperse for 30 minutes to make the interfacial agent fully and evenly distributed.

[0059] Preparation method of interfacial modifier:

[0060] K1:

[0061] Perfluorohexyl acrylene: 500 g

[0062] 1,9-Nonanedithiol: 120 g

[0063] 5-Mercapto-1-methyltetrazole: 10 g

[0064] Benzoin dimethyl ether: 0.2 g

[0065] Tetrahydrofuran: 1700 g

[0066] Introduce nitrogen for 45 minutes to remove oxygen and keep the system inert.

[0067] K2:

[0068] Under room temperature conditions, turn on the 365 nm ultraviolet light irradiation and react for 3 hours. Keep the system stirring and the color gradually deepens.

[0069] K3:

[0070] The tetrahydrofuran was recovered by heating in a 60 °C water bath under reduced pressure distillation to obtain a stable oily modifier liquid.

[0071] 4) Homogeneous mixing:

[0072] The above-mentioned mixed solution was stirred at 25 °C for 2 hours to prepare a transparent and stable decafluoropentene cooling medium.

[0073] Example 3

[0074] 1) Dehydration treatment:

[0075] Take 95 kg of decafluoropentene and dehydrate it at 20 °C for 24 hours in a nitrogen atmosphere.

[0076] 2) Stable additive mixing:

[0077] Add 5 kg of perfluorotributyl ether and stir for 15 minutes to ensure uniform mixing.

[0078] 3) Add interface modifier and disperse:

[0079] Add 0.14 kg of interface modifier, set the ultrasonic power to 50 W, and disperse for 10 minutes.

[0080] Preparation method of interface modifier:

[0081] K1:

[0082] Perfluorohexyl propene: 720 g

[0083] 1,9-Nonanedithiol: 200 g

[0084] 5-Mercapto-1-methyltetrazole: 30 g

[0085] Benzil dimethyl ether: 0.8 g

[0086] Tetrahydrofuran: 2000 g

[0087] Nitrogen was introduced for 60 minutes to ensure thorough deoxygenation.

[0088] K2:

[0089] The ultraviolet lamp (365 nm) was turned on at room temperature (23 °C) for 1.5 hours, and a slight stirring state was maintained during the reaction.

[0090] K3:

[0091] After the reaction, THF was removed using a rotary evaporator under negative pressure (60 mbar) to obtain a high-purity modifier product.

[0092] 4) Homogeneous mixing:

[0093] Stir for 1 hour at 15 °C to finally obtain a cooling medium with excellent stability at low temperatures.

[0094] Example 4

[0095] 1) Dehydration treatment:

[0096] Take 91 kg of decafluoropentene and heat it at 28 °C for 24 hours in an argon atmosphere to fully remove moisture.

[0097] 2) Mixing of stabilizing additives:

[0098] Add 9 kg of perfluorohexane to the dehydrated system and stir for 13 minutes to make it uniform.

[0099] 3) Addition of interfacial modifier and dispersion:

[0100] Add 0.2 kg of interfacial modifier and disperse it for 25 minutes using a 150 W ultrasonic device.

[0101] K1:

[0102] Perfluorohexyl acrylene: 360 g

[0103] 1,9-Nonanedithiol: 100 g

[0104] 5-Mercapto-1-methyltetrazole: 10 g

[0105] Benzoin dimethyl ether: 0.1 g

[0106] Tetrahydrofuran: 1500 g

[0107] Pass nitrogen into the system for 20 minutes to carry out oxygen replacement.

[0108] K2:

[0109] Irradiate with 365 nm ultraviolet light at room temperature (24 °C) and stir and react for 2.5 hours to generate an intermediate.

[0110] K3:

[0111] Carry out vacuum concentration treatment on the reaction solution, gradually remove THF, and obtain a transparent, colorless and viscous liquid for use as a surfactant.

[0112] 4) Homogeneous mixing:

[0113] Stir at 30 °C for 1 hour to prepare a cooling medium with strong thermal stability and suitable for medium and high temperature environments.

[0114] Comparative Example 1

[0115] In this example, except for not adding the interfacial modifier, the rest is the same as in Example 1.

[0116] Comparative Example 2

[0117] In this example, in the preparation step of the interface modifier, except for not adding 5-mercapto-1-methyltetrazole, the rest is the same as in Example 1.

[0118] Test method:

[0119] 1. Cooling performance test (thermal management ability)

[0120] Test equipment: High-performance rack-mounted server (model: Dell R750XS), running under full load.

[0121] Test system: Two-phase immersion cooling system, with the CPU completely immersed in the test coolant.

[0122] Test environment: Room temperature 25°C, running time 48 hours.

[0123] Monitoring items:

[0124] CPU temperature (highest, lowest, average)

[0125] Temperature drop rate (°C / min) within 10 minutes after starting cooling

[0126] Table 1: Cooling performance test results of examples and comparative examples

[0127]

[0128] 2. Thermal stability test (cooling efficiency after aging)

[0129] Test method:

[0130] Place the cooling medium in an environment of 70°C for 72 hours of aging;

[0131] Measure the latent heat of phase change and the retention rate of cooling efficiency (%) after thermal cycling.

[0132] Table 2: Thermal stability test results of examples and comparative examples

[0133] Latent heat of phase change (J / g) Retention rate of cooling efficiency after thermal cycling (%) Example 1 212 97.8 Example 2 209 98.2 Example 3 210 98.6 Example 4 212 98.9 Comparative Example 1 190 95.3 Comparative Example 2 201 96.7

[0134] 3. Wettability test (interface contact effect)

[0135] Test method:

[0136] Drop the cooling medium on the surfaces of aluminum and copper sheets;

[0137] Use a contact angle measuring instrument to measure the wetting angle;

[0138] The smaller the angle, the better the wettability and the higher the heat transfer efficiency.

[0139] Table 3: Wettability test results of the examples and comparative examples

[0140] Wetting angle on the copper sheet surface (°) Wetting angle on the aluminum sheet surface (°) Example 1 86.1 84.2 Example 2 85.7 84.0 Example 3 85.0 83.6 Example 4 84.8 83.2 Comparative Example 1 91.6 86.9 Comparative Example 2 88.7 85.8

[0141] The above specific implementation cases have confirmed the superiority of this formula in terms of cooling efficiency, system thermal stability, cycle life, and improving the wettability of the interface with the equipment.

[0142] The above is only a preferred embodiment of the present invention, and does not impose any limitations on the present invention. Any simple modifications, changes, and equivalent structural changes made to the above embodiments according to the technical essence of the invention still fall within the protection scope of the technical solution of the present invention.

Claims

1. A preparation method of a decafluoropentene cooling medium for phase change cooling, characterized in that, It includes the following steps: (1) By mass, 90 - 95 parts of decafluoropentene raw material are purified and dehydrated under an inert atmosphere. The dehydration operation temperature is 20 - 30 °C, and the dehydration time is 24 hours; (2) The purified decafluoropentene is mixed with 5 - 15 parts of a stabilizing aid and stirred for 10 - 15 minutes; (3) 0.02 - 0.2 parts of an interfacial modifier are added, and ultrasonic equipment is used for dispersion. The dispersion time is 10 - 30 minutes; (4) The mixture obtained in step (3) is stirred at room temperature for 1 - 2 hours until the solution is uniform to obtain a stable cooling medium.

2. The preparation method of a decafluoropentene cooling medium for phase change cooling according to claim 1, wherein: The inert atmosphere is selected from one of nitrogen or argon.

3. The preparation method of a decafluoropentene cooling medium for phase change cooling according to claim 1, characterized in that: The stabilizing aid is selected from one of perfluorotributyl ether or perfluorohexane.

4. The preparation method of a decafluoropentene cooling medium for phase change cooling according to claim 1, characterized in that: The preparation method of the interfacial modifier is as follows: K1: Raw material preparation and mixing: By weight, 36 - 72 parts of perfluorohexyl acrylene, 10 - 20 parts of 1,9 - nonanedithiol, 1 - 3 parts of 5 - mercapto - 1 - methyltetrazole, 0.01 - 0.1 part of benzoin dimethyl ether, and 150 - 200 parts of tetrahydrofuran are added to a reaction vessel. Nitrogen is introduced into the reaction vessel for 15 - 60 minutes to remove oxygen; K2: Photo - initiated addition reaction: An ultraviolet lamp with a wavelength of 365 nm is turned on, and the reaction is stirred at room temperature for 1 - 3 hours; K3: Product separation and purification: After the reaction ends, the reaction mixture is subjected to vacuum distillation to remove the solvent.

5. The preparation method of a decafluoropentene cooling medium for phase change cooling according to claim 1, characterized in that: The dispersion power of the ultrasonic equipment is 50 - 200 W.

6. The preparation method of a decafluoropentene cooling medium for phase change cooling according to claim 1, characterized in that: The room - temperature stirring temperature is 15 - 30 °C.

7. The preparation method of a decafluoropentene cooling medium for phase change cooling according to claim 1, characterized in that: The phase - change cooling system includes a coolant tank, a condenser, a pressure monitor, and a temperature monitor.

8. The preparation method of a decafluoropentene cooling medium for phase change cooling according to claim 1, characterized in that: The decafluoropentene cooling medium is applied to the cooling system of electronic devices, thermal management systems, or new - energy vehicles.

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