COMPOSITION

Abstract

A coolant for cooling an electrical/electronic element by direct immersion cooling, comprising a partially fluorinated ether with the structure (of compound 1) wherein R.sup.1, R.sup.2, R.sup.3, R.sup.4 are independently selected from the group CF.sub.3, alkyl, fluoroalkyl, perfluoroalkyl, haloalkyl perfluorohaloalkyl.

##STR00001##

Claims

1. A coolant for cooling an electrical/electronic element by direct immersion cooling, comprising a partially fluorinated ether with the structure (of compound 1) ##STR00007## wherein R.sup.1, R.sup.2, R.sup.3, R.sup.4 are independently selected from the group comprising H, F, Cl, Br, I, CF.sub.3, alkyl, fluoroalkyl, haloalkyl and R.sup.5 is independently selected from the group CF.sub.3, alkyl, fluoroalkyl, perfluoroalkyl, haloalkyl perfluorohaloalkyl.

2. The coolant according to claim 1, wherein the coolant is water free.

3. The coolant according to claim 1, wherein R.sup.5 is methyl, and preferably R.sup.1 is CF.sub.3 and R.sup.2 to R.sup.4 are all H; or wherein R.sup.5 is methyl, and preferably R.sup.1 is CF.sub.3, R.sup.2 is H, one of R.sup.3 and R.sup.4 is F, and one of R.sup.3 and R.sup.4 is H.

4. The coolant according to claim 1, wherein the coolant additionally comprises a non-flammable fluorinated (partially or per) ether and/or a non-flammable fluorinated (partially or per) ketone.

5. The coolant according to claim 4 wherein the coolant comprises from 1 to 99 wt % of the partially fluorinated ether of compound 1 and from 1 to 99 wt % of a non-flammable fluorinated (partially or per) ether and/or a non-flammable fluorinated (partially or per) ketone.

6. A coolant for cooling a high voltage electrical transmission element by direct immersion cooling, comprising a partially fluorinated ether with the structure (of compound 1) ##STR00008## wherein R.sup.1, R.sup.2, R.sup.3, R.sup.4 are independently selected from the group comprising H, F, Cl, Br, I, CF.sub.3, alkyl, fluoroalkyl, haloalkyl and R.sup.5 is independently selected from the group CF.sub.3, alkyl, fluoroalkyl, perfluoroalkyl, haloalkyl perfluorohaloalkyl.

7. The coolant according to claim 6, wherein the coolant is water free.

8. The coolant according to claim 6, wherein the high voltage electrical transmission element comprises a MV/HV transformer, a circuit breaker, switchgear.

9. The coolant according to claim 6, wherein R.sup.5 is methyl, and preferably R.sup.1 is CF.sub.3 and R.sup.2 to R.sup.4 are all H; or wherein R.sup.5 is methyl, and preferably R.sup.1 is CF.sub.3, R.sup.2 is H, one of R.sup.3 and R.sup.4 is F, and one of R.sup.3 and R.sup.4 is H.

10. The coolant according to claim 6, wherein the coolant additionally comprises a non-flammable fluorinated (partially or per) ether and/or a non-flammable fluorinated (partially or per) ketone.

11. The coolant according to claim 10 wherein the coolant comprises from 1 to 99 wt % of the partially fluorinated ether of compound 1 and from 1 to 99 wt % of a non-flammable fluorinated (partially or per) ether and/or a non-flammable fluorinated (partially or per) ketone.

12. A coolant for cooling an electric vehicle element by direct immersion cooling, comprising a partially fluorinated ether with the structure (of compound 1) ##STR00009## wherein R.sup.1, R.sup.2, R.sup.3, R.sup.4 are independently selected from the group comprising H, F, Cl, Br, I, CF.sup.3, alkyl, fluoroalkyl, haloalkyl and R.sup.5 is independently selected from the group CF.sup.3, alkyl, fluoroalkyl, perfluoroalkyl, haloalkyl perfluorohaloalkyl.

13. The coolant according to claim 12, wherein the coolant is water free.

14. The coolant according to claim 12, wherein the electric vehicle element comprises a battery, an electrical conductor (including components of any charging/discharging system(s)), a motor and/or a gearbox.

15. The coolant according to claim 12, wherein R.sup.5 is methyl, and preferably R.sup.1 is CF.sub.3 and R.sup.2 to R.sup.4 are all H; or wherein R.sup.5 is methyl, and preferably R.sup.1 is CF.sub.3, R.sup.2 is H, one of R.sup.3 and R.sup.4 is F, and one of R.sup.3 and R.sup.4 is H.

16. The coolant according to claim 12, wherein the coolant additionally comprises a non-flammable fluorinated (partially or per) ether and/or a non-flammable fluorinated (partially or per) ketone.

17. The coolant according to claim 16 wherein the coolant comprises from 1 to 99 wt % of the partially fluorinated ether of compound 1 and from 1 to 99 wt % of a non-flammable fluorinated (partially or per) ether and/or a non-flammable fluorinated (partially or per) ketone.

18. A coolant for cooling a computer hardware element by direct immersion cooling, comprising a partially fluorinated ether with the structure (of compound 1) ##STR00010## wherein R.sup.1, R.sup.2, R.sup.3, R.sup.4 are independently selected from the group comprising H, F, Cl, Br, I, CF.sub.3, alkyl, fluoroalkyl, haloalkyl and R.sup.5 is independently selected from the group CF.sub.3, alkyl, fluoroalkyl, perfluoroalkyl, haloalkyl perfluorohaloalkyl.

19. The coolant according to claim 18, wherein the coolant is water free.

20. The coolant according to claim 18, wherein the computer hardware element comprises a server at a data centre.

21. The coolant according to claim 18, wherein R.sup.5 is methyl, and preferably R.sup.1 is CF.sub.3 and R.sup.2 to R.sup.4 are all H; or wherein R.sup.5 is methyl, and preferably R.sup.1 is CF.sub.3, R.sup.2 is H, one of R.sup.3 and R.sup.4 is F, and one of R.sup.3 and R.sup.4 is H.

22. The coolant according to claim 18, wherein the coolant additionally comprises a non-flammable fluorinated (partially or per) ether and/or a non-flammable fluorinated (partially or per) ketone.

23. The coolant according to claim 21 wherein the coolant comprises from 1 to 99 wt % of the partially fluorinated ether of compound 1 and from 1 to 99 wt % of a non-flammable fluorinated (partially or per) ether and/or a non-flammable fluorinated (partially or per) ketone.

24. The coolant according to claim 4, which form an azeotropic or near-azeotropic mixture.

25. The coolant according to claim 24, which comprises 1,1,1,3-tetrafluoro-2-methoxypropane (“Ether A”) or 1,1,1,3,3-pentafluoro-2-methoxypropane (“Ether B”) (both of compound 1) and C.sub.4F.sub.9OCH.sub.3.

26. The coolant according to claim 25, forming an azeotropic or near-azeotropic mixture comprising (preferably consisting of) 10 to 90 wt % C.sub.4F.sub.9OCH.sub.3 and 10 to 90 wt % 1,1,1,3-tetrafluoro-2-methoxypropane (“Ether A”), more preferably 15 to 85 wt % C.sub.4F.sub.9OCH.sub.3 and 15 to 85 wt % 1,1,1,3-tetrafluoro-2-methoxypropane (“Ether A”), more preferably 20 to 80 wt % C.sub.4F.sub.9OCH.sub.3 and 20 to 80 wt % 1,1,1,3-tetrafluoro-2-methoxypropane (“Ether A”), more preferably 30 to 70 wt % C.sub.4F.sub.9OCH.sub.3 and 30 to 70 wt % 1,1,1,3-tetrafluoro-2-methoxypropane (“Ether A”) and most preferably 30 to 60 wt % C.sub.4F.sub.9OCH.sub.3 and 40 to 70 wt % 1,1,1,3-tetrafluoro-2-methoxypropane (“Ether A”).

27. The coolant according to claim 25, forming an azeotropic or near-azeotropic mixture comprising (preferably consisting of) 5 to 70 wt % C.sub.4F.sub.9OCH.sub.3 and 30 to 95 wt % 1,1,1,3,3-pentafluoro-2-methoxypropane (“Ether B”), more preferably 10 to 70 wt % C.sub.4F.sub.9OCH.sub.3 and 30 to 90 wt % 1,1,1,3,3-pentafluoro-2-methoxypropane (“Ether B”), more preferably 10 to 65 wt % C.sub.4F.sub.9OCH.sub.3 and 35 to 90 wt % 1,1,1,3,3-pentafluoro-2-methoxypropane (“Ether B”), more preferably 10 to 60 wt % C.sub.4F.sub.9OCH.sub.3 and 40 to 90 wt % 1,1,1,3,3-pentafluoro-2-methoxypropane (“Ether B”)and most preferably 15 to 60 wt % C.sub.4F.sub.9OCH.sub.3 and 40 to 85 wt % 1,1,1,3,3-pentafluoro-2-methoxypropane (“Ether B”).

28.-31. (canceled)

Description

EXPERIMENTAL SECTION

[0042] The physical properties of 1,1,1,3-tetrafluoro-2-methoxypropane (“Ether A”), 1,1,1,3,3-pentafluoro-2-methoxypropane (“Ether B”), C.sub.4F.sub.9OCH.sub.3 (Novec 7100) and C.sub.4F.sub.9OC.sub.2H.sub.5 (Novec 7200) were determined by a series of experiments.

Experiment 1: Determination of Vapour Pressure

[0043] The liquid to be measured was stored in a cylindrical test cell determine the vapour pressure. The liquid was stirred during the measurement to obtain a quick adjustment of the phase equilibrium in the measuring cell using a magnetic stirrer. The temperature of the test cell was adjusted in a thermostat bath. The temperature in the test cell was measured with a calibrated resistance thermometer (maximum error 0.05 K).

[0044] For the pressure measurement a pressure transmitter from Keller (Serie 35 X HTC 30 bar absolute, error<±0.5% full-scale error≙0.15bar), was attached to the test cell. The Keller Sensor is temperature compensated up to 300° C. 150 ml of test liquid was filled into the test cell and degassed by vacuum. The vapour pressure was recorded in the range 0-120° C. for each fluid. These data were then used to determine the normal (atmospheric pressure) boiling point for each fluid. The normal boiling points found (in ° C.) were:

TABLE-US-00001 Ether A Ether B Novec 7100 Novec 7200 63.0 58.9 59.8 75.5

[0045] The experimental vapour pressures are shown in FIG. 1.

[0046] It was found that the vapour pressure curve of Novec 7100 crossed those of both Ether A and Ether B, indicating that binary mixtures of those ethers with Novec 7100 would form azeotropic compositions.

Experiment 2: Determination of Liquid Viscosity

[0047] The dynamic viscosity was measured using a Cambridge Viscosity Flow-Through Viscometer at static conditions. The measurement procedure is described in ASTM D 7483-13a1 in detail. The viscometer was calibrated with calibration liquids, which are traceable to national standards of viscosity (DKD or NIST calibration, respectively). The temperature was measured with a maximum deviation of 0.15 K. The maximum deviation of the viscosity was 1% Full Scale or maximal 5% of the measured value, depending on which value is lower.

[0048] Results for the four fluids are shown in FIG. 2. It is evident that both Ether A and Ether B have lower viscosities than either Novec 7100 or Novec 7200.

Experiment 3: Determination of Liquid Heat Capacity

[0049] The measurement of the specific heat capacity was done with a differential scanning calorimeter μDSC VII by Setaram. During the procedure, the heat applied to a reference and to the sample was measured over a range of temperatures. The samples were placed into a vessel and heated in steps of 5 K with 0.2 K/min rate of temperature rise. At each 5 K temperature level the temperature was kept constant for half an hour to reach thermal equilibrium. A second empty vessel was heated in parallel in the DSC with the same sequences to compensate thermal influence by the vessel itself. The difference of the thermal absorption behavior of the two empty vessels was measured for every 5 K with the same procedure and subtracted automatically. After the measurement and the calibration run, the specific heat capacity was calculated as function of the temperature with the measured heat and the weight of the sample. The measurement was checked with fluids of well-known specific heat capacity. The uncertainty of the specific heat capacity measurement was below 3%. The results are shown in FIG. 3.

[0050] It is evident that Ether A and Ether B both have significantly higher heat capacity than either Novec 7100 or Novec 7200.

Experiment 4: Determination of Liquid Density

[0051] The liquid density of each of Ether A, Ether B, Novec 7100 and Novec 7200 was measured at room temperature using a calibrated measuring cylinder and microbalance. The densities were found to be (in kg/m.sup.3):

TABLE-US-00002 Ether A Ether B Novec 7100 Novec 7200 1270 1340 1510 1440

[0052] The above combination of properties show that Ether A and Ether B would both require a lower mass and volume flow rate of coolant to remove a constant amount of heat from a heat-generating electronic component or battery pack. This in turn means that pressure drop through the cooling circuit would be lower if these fluids were used as single-phase pumped coolants, resulting in reduced pumping power requirements compared to the Novec fluids. Combination of Ether A with a Novec fluid will therefore improve its ability to remove heat when the resultant liquid is used as a single-phase coolant.

Example 6: Estimation of Azeotropic Mixture Formation

[0053] The vapour pressure data determined in Experiment 1 were used to construct a thermodynamic model based on the Peng-Robinson equation of state to allow estimation of the behaviour of binary mixtures of Ether A and Ether B with the Novec fluids. The critical point parameters required were estimated using the method of Joback as described in the reference text “The Properties of Gases and Liquids”, 5.sup.th edition editors B E Poling, J M Prausnitz, J P O'Connell (pub. McGraw-Hill 2000). The Mathias Copeman temperature function as described in Mathias P. M., Copeman T. W., “Extension of the Peng-Robinson Equation of State to Complex Mixtures: Evaluation of the Various Forms of the Local Composition Concept”, Fluid Phase Equilib., 13, 91-108, 1983. was used to ensure that the model could accurately represent the vapour pressure of each fluid over the range in which experimental data were available.

[0054] Use of this model confirmed the formation of binary minimum-boiling azeotropes of Novec 7100 with Ether A and Ether B in the temperature range 20-100° C., which coincides with typical operating temperature ranges for immersive coolants.