Direct contact type dielectric cooling liquid and preparation method thereof

Abstract

The invention relates to the technical field of liquid cooling of electronic devices of IT equipment, in particular to direct contact type dielectric cooling liquid and a preparation method thereof, the direct contact type dielectric cooling liquid comprises the following raw materials in parts by mass: 100 parts of base oil and 0.2-1.0 part of an additive; the base oil is composed of mineral oil and synthetic hydrocarbon, and the mass of the synthetic hydrocarbon in the base oil accounts for 10-90% of the total mass of the base oil; the additives comprise an antioxidant and a light stabilizer. According to the direct contact type dielectric cooling liquid and the preparation method thereof, the cooling liquid is colorless and transparent, has good flowing property, fireproof safety performance, heat-conducting property, insulating property and oxidation stability, is non-corrosive, has good compatibility with liquid cooling system materials of IT equipment, has good color stability in the use process, and has a good application prospect. The cooling device is not prone to yellowing under the influence of light and heat, is good in environmental protection performance and can meet the requirement for direct contact type cooling of IT equipment.

Description

Technical Field

[0001] The invention relates to the technical field of liquid cooling of electronic devices of IT equipment, and relates to a direct contact type dielectric cooling liquid and a preparation method thereof. Background Art

[0002] With the innovative development of technologies such as artificial intelligence, cloud computing, big data, and blockchain, as well as the advent of the 5G communication era, computer technology has developed rapidly. In order to meet the challenges of network processing performance, IT equipment has continuously improved its processing capabilities and integration, resulting in a steady increase in power density. In addition to the huge energy consumption problem, these changes also put forward higher requirements for refrigeration equipment and technology due to high heat density.

[0003] Traditional air cooling technology faces bottlenecks in high heat density scenarios, and the heat dissipation efficiency can no longer keep up with the computing efficiency. Although the industry has been constantly innovating air cooling systems, the heat carrying capacity of air is far lower than that of liquid, and the cooling capacity of liquid is 1,000 to 3,000 times that of air. Liquid cooling technology has the characteristics of high efficiency, low energy loss, low dependence on buildings for deployment, and quietness and safety. Compared with air cooling, it has incomparable technical advantages. It is an excellent heat dissipation solution that can be applied to scenarios that require a significant increase in computing power, energy efficiency, and deployment density. It can meet the deployment of higher density under conditions of insufficient site power capacity. Therefore, when air cooling is no longer able to cope with high heat, liquid cooling technology gradually moves from behind the scenes to the foreground, attracting widespread attention in the industry.

[0004] In simple terms, the principle of liquid cooling is to use heat convection or heat conduction to remove the heat dissipated by the server through immersion or flow of liquid. The main liquid cooling methods for servers include cold plate liquid cooling, immersion liquid cooling and spray liquid cooling.

[0005] At present, the coolants used in liquid cooling technology mainly include water and fluorinated liquid. Among them: water is a non-insulator and can only be used in non-direct contact cold plate liquid cooling technology. Once a leak occurs, it will cause fatal damage to IT equipment; fluorinated liquid is the most widely used direct contact coolant for immersion, but it is expensive, volatile, has high cost of use, high density, and high load-bearing requirements for buildings. Because water and fluorinated liquid have the above disadvantages as coolants, the relevant industry actively studies and explores the use of oil coolants in direct contact liquid cooling, most of which are studies on synthetic oil and silicone oil coolants.

[0006] The characteristics of electronic components of IT equipment require that the coolant in direct contact with them should have good insulation performance, thermal conductivity, compatibility with materials, non-flammable safety performance, antioxidant stability and eco-friendly performance. At the same time, in order to promptly remove the heat emitted by electronic components, easy to clean and low pump power consumption, the coolant should have good flow performance. In order to keep the coolant's viscosity stable under low temperature and working temperature conditions, the coolant should have a high viscosity index. At present, the performance of coolants provided by both commercial and public literature is still somewhat different from the performance required for direct contact coolants of IT equipment electronic components.

[0007] The Chinese patent document with publication number CN110862806A discloses an electronic device coolant and a preparation method thereof, which uses dimethyl silicone oil, natural ester oil or synthetic ester oil as base oil and adds antioxidants and dispersants to prepare electronic device coolants. The Chinese patent document with publication number CN113861948A discloses a coolant and a preparation method thereof, which uses defoaming agent, oily epoxy resin, dispersant, siloxane, flash point enhancer, and terminal hydroxyl polybutadiene as raw materials to prepare an immersion liquid cooling coolant. Although synthetic oil or silicone oil is cheaper than fluorinated liquid, their prices are still relatively expensive. The Chinese patent document with publication number CN107502309A discloses a mineral oil type coolant and a preparation method thereof, which is prepared by adding a trace amount of antioxidant, defoaming agent and dispersant to a traditional mineral base oil to obtain a coolant, which can be suitable for immersion direct cooling of IT equipment in an open environment. However, the coolant easily turns yellow due to the influence of light and heat, and its oxidation stability (the antioxidant content is far less than the recommended dose and the antioxidant performance can be ignored), non-volatility (evaporation loss in 360 hours is as high as 0.93%), insulation performance (breakdown voltage is only 30kV), low-temperature flowability (pour point -27°C), compatibility with liquid cooling system materials and environmentally friendly performance all need to be improved. Summary of the invention

[0008] The present invention provides a direct contact dielectric coolant and a preparation method thereof, which overcomes the above-mentioned deficiencies of the prior art and can effectively solve the problems of the existing direct contact coolant for electronic components of IT equipment being expensive and having insufficient performance in terms of oxidation stability, insulation performance, and low-temperature flowability.

[0009] One of the technical solutions of the present invention is achieved through the following measures: a direct contact dielectric coolant, the raw materials include 100 parts of base oil and 0.2 to 1.0 parts of additives by mass; the base oil is composed of mineral oil and synthetic hydrocarbons, the mass of the synthetic hydrocarbons in the base oil accounts for 10% to 90% of the total mass of the base oil; the additives include antioxidants and light stabilizers.

[0010] The following is a further optimization and / or improvement of one of the above-mentioned technical solutions: The above-mentioned direct contact dielectric coolant is prepared according to the following method: at 60°C to 70°C, the required amount of mineral oil and synthetic hydrocarbon are mixed to obtain a base oil, and a light stabilizer and an antioxidant are added to the base oil in sequence. After stirring until clear and transparent, the base oil is cooled to room temperature and filtered to obtain a direct contact dielectric coolant.

[0011] The above-mentioned mineral oil is prepared by high-pressure hydrogenation process.

[0012] The above high pressure hydrogenation preparation process conditions are: reaction temperature of 415°C to 435°C, reaction pressure of 17.1MPa to 18.5MPa, space velocity of 0.5h -1 Up to 2.0h -1 The hydrogen-to-oil ratio is 600:1 to 1500:1, and the catalyst is a precious metal catalyst.

[0013] The synthetic hydrocarbon is one or more of polyalphaolefin, synthetic cycloalkane and polypropylene.

[0014] The C of the above mineral oils and synthetic hydrocarbons A The values ​​(aromatic content) are all 0.

[0015] The antioxidant is one or more of 2,6-di-tert-butyl-p-cresol, 2,6-di-tert-butylphenol and L57 antioxidant, and the amount of the antioxidant is 0.18% to 0.9% of the base oil mass.

[0016] The light stabilizer is one or more of UV326, UV328 and UV531, and the amount of the light stabilizer is 0.02% to 0.1% of the base oil mass.

[0017] The kinematic viscosity of the above direct contact dielectric coolant at 40°C is 4 mm 2 / s to 60mm 2 / s, pour point ≤-60℃.

[0018] The second technical solution of the present invention is achieved through the following measures: a method for preparing a direct contact dielectric coolant, which is carried out according to the following steps: at 60°C to 70°C, the required amount of mineral oil and synthetic hydrocarbon are mixed to obtain a base oil, a light stabilizer and an antioxidant are added to the base oil in sequence, the mixture is stirred until clear and transparent, the mixture is cooled to room temperature, and the direct contact dielectric coolant is obtained after filtering.

[0019] The present invention provides a direct contact dielectric coolant and a preparation method thereof. The coolant is colorless and transparent, has good flowability, fire safety performance, thermal conductivity, insulation performance and oxidation stability, is non-corrosive, has good compatibility with IT equipment liquid cooling system materials, has good color stability during use, is not easily yellowed by light and heat, has good environmental protection, and can meet the needs of direct contact cooling of IT equipment. DETAILED DESCRIPTION

[0020] The present invention is not limited by the following embodiments, and the specific implementation method can be determined according to the technical scheme of the present invention and the actual situation. Unless otherwise specified, the various chemical reagents and chemicals mentioned in the present invention are all known and commonly used chemical reagents and chemicals in the prior art; unless otherwise specified, the percentages in the present invention are all mass percentages; the normal temperature and room temperature in the present invention generally refer to the temperature of 15°C to 25°C, and are generally defined as 25°C.

[0021] The present invention will be further described below in conjunction with embodiments: Embodiment 1: The direct contact dielectric coolant comprises raw materials, by mass, of 100 parts of base oil and 0.2 to 1.0 parts of additives; the base oil is composed of mineral oil and synthetic hydrocarbons, the mass of the synthetic hydrocarbons in the base oil accounts for 10% to 90% of the total mass of the base oil; the additives include antioxidants and light stabilizers.

[0022] Example 2: As an optimization of the above example, the direct contact dielectric coolant is prepared by the following method: at 60°C to 70°C, a required amount of mineral oil and synthetic hydrocarbon are mixed to obtain a base oil, a light stabilizer and an antioxidant are added to the base oil in sequence, the mixture is stirred until clear and transparent, cooled to room temperature, and filtered to obtain a direct contact dielectric coolant. The preparation process of the direct contact dielectric coolant is carried out at a temperature of 60°C to 70°C to ensure that the light stabilizer is fully dissolved.

[0023] Example 3: As an optimization of the above example, mineral oil is prepared by high pressure hydrogenation (deep hydrogenation) process.

[0024] Example 4: As an optimization of the above Example 3, the preparation process conditions of high-pressure hydrogenation are: reaction temperature is 415°C to 435°C, reaction pressure is 17.1MPa to 18.5MPa, and space velocity is 0.5h -1 Up to 2.0h -1 , the hydrogen-to-oil ratio is 600:1 to 1500:1, and the catalyst is a precious metal catalyst (such as a platinum catalyst or a palladium catalyst).

[0025] Embodiment 5: As an optimization of the above embodiment, the synthetic hydrocarbon is one or more of poly-alpha-olefin, synthetic cycloalkane and polypropylene.

[0026] Example 6: As an optimization of the above example, C of mineral oil and synthetic hydrocarbons A The values ​​(aromatic content) are all 0.

[0027] Example 7: As an optimization of the above example, the antioxidant is one or more of 2,6-di-tert-butyl-p-cresol, 2,6-di-tert-butylphenol and L57 antioxidant, and the amount of the antioxidant is 0.18% to 0.9% of the base oil mass.

[0028] Example 8: As an optimization of the above example, the light stabilizer is one or more of UV326, UV328 and UV531, and the amount of the light stabilizer is 0.02% to 0.1% of the base oil mass. UV326, UV328 and UV531 are ultraviolet absorbers UV326, UV328 and UV531.

[0029] Example 9: As an optimization of the above example, the direct contact dielectric coolant has a kinematic viscosity of 4 mm at 40°C. 2 / s to 60mm 2 / s, pour point ≤-60℃.

[0030] The present invention provides a direct contact dielectric coolant, which is prepared by adding an antioxidant and a light stabilizer to a base oil blended with mineral oil and synthetic hydrocarbons. The base oil of the present invention uses mineral oil and synthetic hydrocarbons, wherein the synthetic hydrocarbons used have excellent performance compared to other synthetic oils, and have a higher viscosity index and excellent anti-oxidation stability. Moreover, since the synthetic hydrocarbon has a single component and no impurities, the stability of the coolant is also improved, and the service life is long. The other component of the base oil, mineral oil, has low cost, good fluidity, and good compatibility with IT equipment liquid cooling system materials. In addition, the base oil selected by the present invention has good stability and low-temperature fluidity, low evaporation loss, high flash point, non-flammable, good toxicity and biodegradability, and both mineral oil and synthetic hydrocarbons do not contain aromatic hydrocarbons, and have good environmental protection. On this basis, the direct contact dielectric coolant of the present invention only adds two additives, wherein the antioxidant can effectively improve the oxidation stability of the dielectric coolant, and the light stabilizer can prevent the coolant from turning yellow due to light and heat, and can further increase the oxidation stability.

[0031] Embodiment 10 to embodiment 14: The preparation is carried out according to the following steps: according to the raw material composition in Table 1, at a temperature of 60°C to 70°C, the required amount of mineral oil and synthetic hydrocarbon are fully mixed and blended to obtain a base oil; light stabilizer and antioxidant are sequentially added to the base oil, stirred at 60°C to 70°C until clear and transparent, cooled to room temperature, and filtered to obtain a direct contact dielectric coolant. The raw material composition and proportion of Examples 10 to 14 are shown in Table 1.

[0032] Comparative Example 1: The difference between this coolant and Example 12 is that the base oil is 100% mineral oil, and the other components, amounts and blending temperature are the same as those in Example 12.

[0033] Comparative Example 2: This coolant differs from Example 11 in that no light stabilizer is added, and the other components, amounts and blending temperature are the same as those of Example 11.

[0034] Comparative Example 3: The difference between this coolant and Example 11 is that the light stabilizer UV326 is replaced by UV622, and the added amount is 0.02 g. The other components, amounts and blending temperature are the same as those in Example 11.

[0035] Comprehensive performance test: The viscosity index, rotating oxygen bomb, -40°C kinematic viscosity, flash point, biodegradability, breakdown voltage and thermal conductivity of the direct contact dielectric coolant of Example 12 and the coolant of Comparative Example 1 were tested, and the performance comparison is shown in Table 2. As can be seen from Table 2, the direct contact dielectric coolant of Example 12 using mineral oil and synthetic hydrocarbon as base oil has a higher viscosity index and better viscosity-temperature performance than the coolant of Comparative Example 1 using only mineral oil as base oil, and Example 12 is also better in terms of rotating oxygen bomb time (antioxidation ability), -40°C low-temperature flow performance, flash point (fire safety), biodegradability and thermal conductivity. That is, the various use properties of the direct contact dielectric coolant of the present invention using mineral oil and synthetic hydrocarbon as base oil are better than the coolant using only mineral oil as base oil. In addition, since the direct contact dielectric coolant base oil itself has excellent performance and can meet many performance requirements of dielectric coolant products, there is no need to add additives such as flash point enhancers and oily epoxy resins. Only antioxidants and light stabilizers need to be added to prepare dielectric coolant products with excellent performance. The ingredients are simple, so there is no need to add dispersants to make the coolant have good stability, which can well meet the needs of IT equipment liquid cooling systems.

[0036] Study on the effect of light stabilizer: The direct contact dielectric coolant of Example 11 and the coolants of Comparative Examples 2 and 3 were tested for light and heat stability and compatibility with liquid cooling system materials, and the performance test results are compared in Table 3. As can be seen from Table 3, the light and heat stability of Example 11 with 0.02% light stabilizer UV326 added is significantly better than that of Comparative Example 2 without light stabilizer UV326, indicating that light stabilizer UV326 can improve the light and heat stability of the coolant; from the test results of Example 11 and Comparative Example 3, it can be seen that the light and heat stability of the coolant with 0.02% light stabilizer UV622 added is not as good as that of the coolant with 0.02% light stabilizer UV326 added, and the coolant with 0.02% light stabilizer UV622 added is incompatible with the liquid cooling system materials, while Comparative Example 2 without any light stabilizer added is compatible with the liquid cooling system materials, indicating that light stabilizer UV622 has an adverse effect on the compatibility of liquid cooling system materials.

[0037] Run the tests: The direct contact dielectric coolants of Examples 10 to 14 were added to the server respectively, and the CPU load of the server immersed in the coolant was 100% to test the overall compatibility of the direct contact dielectric coolant with the server. The test time was 16 months, and the server parameters were regularly monitored every week. The test results are shown in Table 4. It can be seen from Table 4 that the direct contact dielectric coolants of Examples 10 to 14 have low volatility, with an annual volatility loss of about 1.5wt%, which does not affect the operation and maintenance of the server; the coolant is not easy to absorb water, and the water content has no obvious change during the 16-month operation process, and it is safe to use; it is compatible with the liquid cooling system materials and meets the long-term use requirements of the equipment; the server is in good operating condition, and all parameters are normal, indicating that the coolant has good thermal conductivity and high heat dissipation efficiency.

[0038] In summary, the present invention provides a direct contact dielectric coolant, which uses mineral oil and synthetic hydrocarbon as base oil, and is supplemented with a small amount of additives, to obtain good oxidation stability (rotating oxygen bomb> 600min and annual volatilization loss of about 1.5%), thermal conductivity, insulation performance, material compatibility, flowability, fire safety performance and environmental protection performance, and the dielectric coolant is colorless and transparent, and has a kinematic viscosity of 40°C of 4mm 2 / s to 60mm 2 / s, pour point ≤-60°C, high viscosity index, so that it can maintain stable viscosity under low temperature and working temperature conditions, good low temperature fluidity and pumpability, non-corrosive, not easy to turn yellow due to light and heat, good stability during use, the direct contact dielectric coolant of the present invention has the advantages of both synthetic oil and mineral oil, takes into account economy and performance, and has a good application prospect as an IT equipment coolant.

[0039] The above technical features constitute the embodiments of the present invention, which have strong adaptability and implementation effect. Non-essential technical features can be added or reduced according to actual needs to meet the requirements of different situations.

Claims

1. A direct contact dielectric coolant, characterized in that The raw materials include 100 parts of base oil and 0.2 to 1.0 parts of additives by mass; the base oil is composed of mineral oil and synthetic hydrocarbons, and the mass of the synthetic hydrocarbons in the base oil accounts for 10% to 90% of the total mass of the base oil; the additives include antioxidants and light stabilizers.

2. The direct contact dielectric coolant according to claim 1, characterized in that The direct contact dielectric coolant is prepared according to the following method: at 60°C to 70°C, a required amount of mineral oil and synthetic hydrocarbon are mixed to obtain a base oil, a light stabilizer and an antioxidant are added to the base oil in sequence, the mixture is stirred until clear and transparent, the mixture is cooled to room temperature, and the direct contact dielectric coolant is obtained after filtering.

3. The direct contact dielectric coolant according to claim 1 or 2, characterized in that Mineral oil is produced by high pressure hydrogenation process.

4. The direct contact dielectric coolant according to claim 3, characterized in that The preparation process conditions of high-pressure hydrogenation are: reaction temperature of 415℃ to 435℃, reaction pressure of 17.1MPa to 18.5MPa, space velocity of 0.5h -1 Up to 2.0h -1 The hydrogen-to-oil ratio is 600:1 to 1500:1, and the catalyst is a precious metal catalyst.

5. The direct contact dielectric coolant according to claims 1 to 4, characterized in that The synthetic hydrocarbon is one or more of polyalphaolefin, synthetic cycloalkane and polypropylene.

6. The direct contact dielectric coolant according to any one of claims 1 to 5, characterized in that C of mineral oils and synthetic hydrocarbons A The values ​​are all 0.

7. The direct contact dielectric coolant according to any one of claims 1 to 6, characterized in that The antioxidant is one or more of 2,6-di-tert-butyl-p-cresol, 2,6-di-tert-butylphenol and L57 antioxidant, and the amount of the antioxidant is 0.18% to 0.9% of the base oil mass.

8. The direct contact dielectric coolant according to any one of claims 1 to 7, characterized in that The light stabilizer is one or more of UV326, UV328 and UV531, and the amount of the light stabilizer used is 0.02% to 0.1% of the base oil mass.

9. The direct contact dielectric coolant according to any one of claims 1 to 8, characterized in that Direct contact dielectric coolant has a kinematic viscosity of 4 mm at 40°C 2 / s to 60mm 2 / s, pour point ≤-60℃.

10. A method for preparing the direct contact dielectric coolant according to claim 1 or 3 or 4 or 5 or 6 or 7 or 8 or 9, characterized in that The process is as follows: at 60°C to 70°C, a required amount of mineral oil and synthetic hydrocarbon are mixed to obtain a base oil, a light stabilizer and an antioxidant are added to the base oil in sequence, the mixture is stirred until clear and transparent, the mixture is cooled to room temperature, and a direct contact dielectric coolant is obtained after filtering.

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