A near-azeotropic fluorinated liquid composition and its application

Abstract

The present invention discloses a near-azeotropic fluorinated liquid composition and its application. The fluorinated liquid composition comprises: 30-80% by mass of hexafluoropropylene dimer and 20-70% by mass of tetradecafluorohexane. The fluorinated liquid composition forms a near-azeotropic composition at a temperature of 48.6-58.6°C and a pressure range of 86.3-116.3 kPa. The fluorinated liquid composition is a uniform and stable liquid at room temperature and pressure, exhibiting advantages such as insulating properties, non-flammability, a low dielectric constant, and good stability. It can be used as a phase-change coolant in cooling systems for electronic equipment such as data center processors or supercomputers, as well as a circulating medium in heat pipe systems, high-temperature heat pump systems, and organic Rankine cycle systems.

Description

Technical Field

[0001] The present invention relates to a heat transfer fluid, in particular to a near-azeotropic fluorinated liquid composition and application thereof. Background Art

[0002] With the rapid development of IT technology, data processing volumes are increasing, and computing speeds are constantly increasing. This has led to a continuous increase in the energy consumption of data center server equipment and the heat generated by CPUs during operation. All of these have posed a huge challenge to traditional air cooling. In addition to its huge energy consumption, air cooling is also gradually failing to meet the cooling needs of data centers.

[0003] Liquid cooling is gradually replacing traditional air cooling. Instead of requiring a compressor as a power source, servers are directly immersed in a coolant, which circulates to remove heat generated in the data center. Furthermore, because the specific heat of liquids is much greater than that of gases, the heat transfer efficiency of liquid cooling is much higher than that of air cooling. Data centers using liquid cooling can significantly reduce equipment operating energy consumption, lowering the power usage effectiveness (PUE) to below 1.2.

[0004] In immersion phase-change liquid cooling systems, the boiling point of a single working fluid cannot be adjusted, often failing to precisely match the data center's operating power. This limitation can be addressed by using a multi-component mixed medium. Most mixed media are non-azeotropic, exhibiting significant temperature glide. When leaks occur, the mixture's composition changes significantly, necessitating re-measurement of the liquid's composition and readjustment of the refill ratio during the refill process. Summary of the Invention

[0005] In order to solve the above technical problems, the present invention proposes a near-azeotropic fluorinated liquid composition with insulating properties, non-flammability, low dielectric constant and good stability.

[0006] The physical properties of the components of the fluorinated liquid composition of the present invention are as follows:

[0007] Hexafluoropropylene dimer has the molecular formula (CF3)FC=CFCF(CF3)2, a molecular weight of 300.5, a standard boiling point of 48°C, a critical temperature of 169.92°C, and a critical pressure of 1.732 MPa.

[0008] Tetradecafluorohexane has a molecular formula of CF3(CF2)4CF3, a molecular weight of 338.04, a standard boiling point of 57.12°C, a critical temperature of 174.85°C, and a critical pressure of 1.7416MPa.

[0009] Perfluorohexanone has a molecular formula of CF3CF2C(=O)CF(CF3)2, a molecular weight of 316.04, a standard boiling point of 49.05°C, a critical temperature of 168.66°C, and a critical pressure of 1.869 MPa.

[0010] Perfluoromethylcyclopentane has a molecular formula of (CF2)4CFCF3, a molecular weight of 300.5, a standard boiling point of 48°C, a critical temperature of 184.32°C, and a critical pressure of 2.7155MPa.

[0011] The relevant physical properties of tetradecafluorohexane and perfluorohexanone can be obtained through REFPROP query. The critical parameters of hexafluoropropylene dimer and perfluoromethylcyclopentane are calculated according to the Marrero-Pardillo group contribution method:

[0012] The critical temperature calculation formula is as follows:

[0013]

[0014] Where, T b is the standard boiling point, tcbk is the contribution of the kth type of atoms to the critical temperature obtained by regression, N k is the number of atom pairs of type k.

[0015] The critical pressure calculation formula is as follows:

[0016]

[0017] Where N atoms is the number of atoms, and pcbk is the contribution of the kth type of atoms to the critical pressure obtained by regression.

[0018] The purpose of the present invention is achieved through the following technical solutions:

[0019] A near-azeotropic fluorinated liquid composition comprising: 30-80% by weight of hexafluoropropylene dimer and 20-70% by weight of tetradecafluorohexane. Preferably, the fluorinated liquid composition comprises: 40-60% by weight of hexafluoropropylene dimer and 40-60% by weight of tetradecafluorohexane.

[0020] The fluorinated liquid composition of the present invention can form a near-azeotropic composition at a temperature of 48.6 to 58.6° C. and a pressure range of 86.3 to 116.3 kPa.

[0021] The hexafluoropropylene dimer of the present invention includes a cis structure and a trans structure, as shown below:

[0022]

[0023] Furthermore, the fluorinated liquid composition of the present invention also includes a third component selected from perfluorohexanone and / or perfluoromethylcyclopentane. Specifically, the fluorinated liquid composition includes: 10-50% by weight of hexafluoropropylene dimer, 30-80% by weight of tetradecafluorohexane, and 10-60% by weight of the third component. Preferably, the hexafluoropropylene dimer, tetradecafluorohexane, and the third component are present in an amount of 20-40% by weight, 30-50% by weight, and 30-50% by weight, respectively.

[0024] At a temperature of 49.2 to 58.0° C. and a pressure range of 86.3 to 116.3 kPa, the fluorinated liquid composition containing the third component can also form a near-azeotropic composition.

[0025] The fluorinated liquid composition of the present invention can be formed into a uniform and stable composition by physically mixing the components according to the above mass ratio under normal temperature and pressure.

[0026] The fluorinated liquid composition has insulating properties, is non-flammable and has good stability, a boiling point of 50-60°C, a freezing point of less than -35°C, and a dielectric constant of less than 2. The working environment temperature of the fluorinated liquid composition is between 50-120°C.

[0027] The present invention also provides the use of any of the above-mentioned near-azeotropic fluorinated liquid compositions, in particular, the fluorinated liquid composition is used as a phase change coolant in an electronic equipment cooling system, as well as a circulating medium in a heat pipe system, a high-temperature heat pump system, and an organic Rankine cycle system.

[0028] Furthermore, the electronic equipment cooling system is a data center processor or a supercomputer.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] 1. The fluorinated liquid composition of the present invention has good insulation and chemical stability, and the composition itself is non-flammable and safe and reliable during use.

[0031] 2. The fluorinated liquid composition of the present invention is a near-azeotropic mixture. During the phase change process, the gas-liquid phase composition changes little. Once a leak occurs, the composition change caused by gas escape is also weak. The original proportion of liquid can be added for rehydration. There is no need to detect the content of the composition in the system, and maintenance is convenient.

[0032] 3. The freezing point of the fluorinated liquid composition of the present invention is less than -35°C, and it has long-term compatibility with PET, PA, glue, plastic, metal (aluminum alloy, steel alloy), etc., and does not react or dissolve in them. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1A relationship diagram of the bubble dew point temperature of the fluorinated liquid composition of Example 2 of the present invention and Comparative Example 2 at different pressures is provided;

[0034] Figure 2 A relationship diagram of the bubble dew point temperature of the fluorinated liquid composition of Example 8 of the present invention and Comparative Example 2 at different pressures is provided;

[0035] Figure 3 A relationship diagram of the dew point temperature of the fluorinated liquid composition of Example 12 of the present invention and Comparative Example 2 at different pressures is provided;

[0036] Figure 4 A relationship diagram of the bubble dew point temperature of the fluorinated liquid composition of Example 17 of the present invention and Comparative Example 2 at different pressures is given. DETAILED DESCRIPTION

[0037] The present invention will be further described below with reference to specific embodiments, but the present invention is not limited to these specific embodiments. Those skilled in the art should recognize that the present invention covers all possible alternatives, improvements and equivalents within the scope of the claims.

[0038] The basic physical properties of the components of the fluorinated liquid composition according to the present invention are shown in Table 1 below:

[0039] Table 1 Basic physical properties of each component of the fluorinated liquid composition

[0040]

[0041] The fluorinated liquid compositions of the Examples and Comparative Examples of the present invention were prepared as follows: the components were mixed in liquid form at room temperature and pressure according to the corresponding mass percentages, and stirred to obtain a uniform and stable composition, wherein the sum of the mass percentages of the components of each composition was 100%. The compositions of the Examples and Comparative Examples are shown in Table 2 below:

[0042] Table 2, Examples and Comparative Examples Composition

[0043]

[0044]

[0045] The fluorinated liquid compositions of the above examples and comparative examples were subjected to various performance tests:

[0046] 1. Flammability

[0047] The flammability test of the fluorinated liquid compositions of Examples 1-21 and Comparative Examples 1-4 was conducted using the national standard GB / T 12474-2008. The test results showed that the fluorinated liquid compositions of Examples 1-21 were all non-flammable, while the fluorinated liquid compositions of Comparative Examples 1-4 were all flammable.

[0048] 2. Temperature Glide, Evaporation Enthalpy and Environmental Performance

[0049] Table 3 below gives the physical properties data such as temperature glide, density, vaporization enthalpy, dielectric constant and environmental performance of each embodiment and comparative example, as shown below:

[0050] Table 3. Physical property test results

[0051]

[0052]

[0053] Note: The dew point temperature in the table is tested using GB / T615-2006, the density is tested using GB / T2013-2010, and the dielectric constant is tested using GB / T1409-2006.

[0054] As can be seen from Table 3 above, the temperature glide of the fluorinated liquid composition of the present invention is <1°C, which is a near-azeotropic mixture, and the boiling temperature range is between 50 and 60°C. In the application of immersion phase change liquid cooling in data centers, the boiling temperature and component content of the liquid are stable, which is convenient for temperature control management and subsequent maintenance and rehydration of the data center. At the same time, the fluorinated liquid compositions of the present invention are non-flammable, and the dielectric constant is <2, which has no effect on the signal transmission of the data center, and is particularly suitable for the immersion phase change liquid cooling system of the data center. However, the temperature glide of the fluorinated liquid composition of Comparative Examples 1-4 is >4°C. Once a leak occurs in the system, it is necessary to detect the content of the remaining components in the system and calculate the components and content that need to be replenished. The operation is complicated and time-consuming.

[0055] Figure 1-4 The relationship diagrams of the bubble dew point temperature under different pressure conditions are given for Example 2, Example 8, Example 12, Example 17 and Comparative Example 2 respectively. Figure 1-4 As can be seen from the graph, the dew point temperatures of the different example compositions vary and all increase with increasing ambient pressure. Under varying ambient pressures, the temperature glide (<1°C) of all example compositions is significantly less than that of the comparative example (≈5°C). Therefore, the example compositions can be adjusted in their components and proportions to achieve different operating temperatures during use, while maintaining relatively stable temperatures, facilitating system control.

Claims

1. A near-azeotropic fluorinated liquid composition, characterized in that: The fluorinated liquid composition is composed of the following components: 10-50% by mass of hexafluoropropylene dimer, 30-80% by mass of tetradecafluorohexane, and 10-60% by mass of a third component, wherein the third component is selected from perfluorohexanone and / or perfluoromethylcyclopentane; At a temperature of 49.2 to 58.0° C. and a pressure range of 86.3 to 116.3 kPa, the fluorinated liquid composition forms a near-azeotropic composition with a temperature glide of less than 1° C.; and the dielectric constant of the fluorinated liquid composition is less than 2.

2. The near-azeotropic fluorinated liquid composition according to claim 1, wherein: The hexafluoropropylene dimer includes a cis structure and a trans structure.

3. The near-azeotropic fluorinated liquid composition according to any one of claims 1-2, characterized in that: The working environment temperature of the fluorinated liquid composition is between 50 and 120°C.

4. The use of the near-azeotropic fluorinated liquid composition according to any one of claims 1 to 2, characterized in that: The fluorinated liquid composition is used as a phase-change coolant in an electronic equipment cooling system, and as a circulating medium in a heat pipe system, a high-temperature heat pump system, and an organic Rankine cycle system.

5. The use of the near-azeotropic fluorinated liquid composition according to claim 4, characterized in that: The electronic equipment cooling system is a data center processor or a supercomputer.

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