BIODEGRADABLE COOLANT BY DIRECT IMMERSION

Abstract

The invention relates to the use, as a direct immersion cooling fluid, of a composition comprising from 80 to 100% by weight, relative to the total weight of the composition, said hydrocarbon fluid comprising at least 90% by weight of a hydrocarbon fluid comprising at least 90% by weight of isoparaffins and less than 100 ppm by weight of aromatics, relative to the total weight of the hydrocarbon fluid, said hydrocarbon fluid having a biodegradability at 28 days measured according to the OECD 301B standard greater than or equal to 60%.

Description

Title of the invention: BIODEGRADABLE COOLING FLUID BY DIRECT IMMERSION TECHNICAL FIELD OF THE INVENTION

[0001] The invention relates to the use of an easily biodegradable isoparaffinic fluid as a direct immersion cooling fluid, in particular for data centers. The invention also relates to a cooling system and a method for cooling by direct immersion in an easily biodegradable isoparaffinic cooling fluid. STATE OF THE ART

[0002] The data economy is booming. Many aspects of our daily lives—smart devices, homes, cities, and autonomous vehicles—rely on data centers, which include many computers and servers. These centers come at a significant cost in terms of energy consumption.

[0003] Many techniques may be used to cool electronic devices (e.g., processors, memories, networking devices, and other heat-generating devices) that are located in data centers. For example, forced convection may be created by providing a flow of cooling air over the devices. Fans located near the devices, fans located in computer server rooms, and / or fans located in ducts in fluid communication with the air surrounding the electronic devices, may force the flow of cooling air into the data centers.

[0004] More recently, cooling systems by immersion in a coolant liquid have been developed.

[0005] Single-phase direct immersion liquid cooling means that the coolant does not change phase during the process of cooling (dissipating heat) the data center components.

[0006] Single-phase direct immersion coolants have been developed. These are typically fluorocarbon compounds. These compounds are powerful greenhouse gases that can have an impact on the ozone layer (Global Warming Potential).

[0007] The present invention aims to provide an easily biodegradable hydrocarbon fluid as a single-phase direct immersion cooling fluid for data centers. Summary of the invention

[0008] The invention relates to the use, as a direct immersion cooling fluid, of a composition comprising from 80 to 100% by weight, relative to the total weight of the composition, said hydrocarbon fluid comprising at least 90% by weight of a hydrocarbon fluid comprising at least 90% by weight of isoparaffins and less than 100 ppm by weight of aromatics, relative to the total weight of the hydrocarbon fluid, said hydrocarbon fluid having a biodegradability at 28 days measured according to the OECD 301B standard greater than or equal to 60%.

[0009] According to one embodiment, the hydrocarbon fluid comprises, relative to the total weight of the hydrocarbon fluid: - at least 95% by weight of isoparaffins, and / or - at most 5% by weight of normal paraffins, and / or - at most 1% by weight of naphthenes, and / or - less than 50 ppm by weight of aromatics.

[0010] According to one embodiment, the hydrocarbon fluid has: - a flash point greater than or equal to 110°C, preferably greater than or equal to 120°C, or even greater than or equal to 140°C according to standard ASTM D93, and / or - a kinematic viscosity at 40°C less than or equal to 5 cSt, preferably less than or equal to 4 cSt.

[0011] According to one embodiment, the hydrocarbon fluid has: - an initial boiling point and a final boiling point in the range from 200 to 400°C, preferably from 240 to 350°C, more preferably from 250 to 340°C, and / or - a difference between the final boiling point and the initial boiling point ranging from 10°C to 80°C, preferably from 20°C to 50°C.

[0012] According to one embodiment, the hydrocarbon fluid comprises, relative to the total weight of the hydrocarbon fluid: - from 30 to 60% by weight of C15 isoparaffins and from 30 to 60% by weight of C16 isoparaffins, or - from 5 to 15% by weight of C15 isoparaffins, from 30 to 60% by weight of C16 isoparaffins, from 10 to 30% by weight of C17 isoparaffins, and from 10 to 30% by weight of C18 isoparaffins, or - from 10 to 30% by weight of C17 isoparaffins and from 60 to 90% by weight of C18 isoparaffins.

[0013] According to one embodiment, the composition comprises 100% by weight of the cooling fluid.

[0014] According to another embodiment, the composition further comprises, with respect to the total weight of the composition, from 0.01 to 20% by weight of additives preferably chosen from antioxidants, flame retardants and their mixture.

[0015] The invention also relates to an immersion cooling system. direct, including: - a bath comprising a composition comprising 80 to 100% by weight of a hydrocarbon fluid, relative to the total weight of the composition, said hydrocarbon fluid comprising at least 90% by weight of isoparaffins and less than 100 ppm by weight of aromatics, relative to the total weight of the hydrocarbon fluid, said hydrocarbon fluid having a biodegradability at 28 days measured according to the OECD 301B standard greater than or equal to 60%, - at least one organ to be cooled partially or totally immersed in the composition.

[0016] According to one embodiment of the cooling system, the member to be cooled is an organ of a data center.

[0017] According to one embodiment of the cooling system, the hydrocarbon fluid includes one or more of the following features: - the hydrocarbon fluid comprises, in relation to the total weight of the hydrocarbon fluid: at least 95% by weight of isoparaffins, and / or at most 5% by weight of normal paraffins, and / or at most 1% by weight of naphthenes, and / or less than 50 ppm by weight of aromatics; and / or the hydrocarbon fluid presents: • a flash point greater than or equal to 110°C, preferably greater than or equal to 120°C, or even greater than or equal to 140°C according to standard ASTM D93, and / or • a kinematic viscosity at 40°C less than or equal to 5 cSt, of preference less than or equal to 4 cSt; and / or the hydrocarbon fluid presents: • an initial boiling point and a final boiling point in the range from 200 to 400°C, preferably from 240 to 350°C, more preferably from 250 to 340°C, and / or • a difference between the final boiling point and the initial boiling point ranging from 10°C to 80°C, preferably from 20°C to 50°C; and / or the hydrocarbon fluid comprises, relative to the total weight of the hydrocarbon fluid: from 30 to 60% by weight of C15 isoparaffins and from 30 to 60% by weight of C16 isoparaffins, or • from 5 to 15% by weight of C15 isoparaffins, from 30 to 60% by weight of C16 isoparaffins, from 10 to 30% by weight of C17 isoparaffins, and from 10 to 30% by weight of C18 isoparaffins, or • from 10 to 30% by weight of C17 isoparaffins and from 60 to 90% by weight of C18 isoparaffins.

[0018] According to one embodiment of the cooling system, the composition comprises 100% by weight of the cooling fluid.

[0019] According to one embodiment of the cooling system, the composition further comprises, relative to the total weight of the composition, from 0.01 to 20% by weight of additives preferably chosen from antioxidants, flame retardants and their mixture.

[0020] The invention also relates to a method of cooling by direct immersion comprising a step of total or partial immersion of at least one member to be cooled in a composition comprising 80 to 100% by weight of a hydrocarbon fluid, relative to the total weight of the composition, said hydrocarbon fluid comprising at least 90% by weight of isoparaffins and less than 100 ppm by weight of aromatics, relative to the total weight of the hydrocarbon fluid, said hydrocarbon fluid having a biodegradability at 28 days measured according to the OECD 301B standard greater than or equal to 60%, relative to the total weight of carbon atoms.

[0021] According to one embodiment of the cooling method, the organ to be cooled is an organ of a data center.

[0022] According to one embodiment of the cooling method, the organ to be cooled is an organ of a data center.

[0023] According to one embodiment of the cooling method, the hydrocarbon fluid comprises one or more of the following characteristics: - the hydrocarbon fluid comprises, in relation to the total weight of the hydrocarbon fluid: • at least 95% by weight of isoparaffins, and / or • at most 5% by weight of normal paraffins, and / or • at most 1% by weight of naphthenes, and / or • less than 50 ppm by weight of aromatics; - and / or the hydrocarbon fluid presents: • a flash point greater than or equal to 110°C, preferably greater than or equal to 120°C, or even greater than or equal to 140°C according to standard ASTM D93, and / or • a kinematic viscosity at 40°C less than or equal to 5 cSt, preferably less than or equal to 4 cSt; - and / or the hydrocarbon fluid presents: • an initial boiling point and a final boiling point in the range from 200 to 400°C, preferably from 240 to 350°C, more preferably from 250 to 340°C, and / or • a difference between the final boiling point and the initial boiling point ranging from 10°C to 80°C, preferably from 20°C to 50°C; - and / or the hydrocarbon fluid comprises, relative to the total weight of the hydrocarbon fluid: • from 30 to 60% by weight of C15 isoparaffins and from 30 to 60% by weight of C16 isoparaffins, or • from 5 to 15% by weight of C15 isoparaffins, from 30 to 60% by weight of C16 isoparaffins, from 10 to 30% by weight of C17 isoparaffins, and from 10 to 30% by weight of C18 isoparaffins, or • from 10 to 30% by weight of C17 isoparaffins and from 60 to 90% by weight of C18 isoparaffins.

[0024] According to one embodiment of the cooling method, the composition comprises 100% by weight of the cooling fluid.

[0025] According to one embodiment of the cooling method, the composition further comprises, relative to the total weight of the composition, from 0.01 to 20% by weight of additives preferably chosen from antioxidants, flame retardants and their mixture.

[0026] The invention makes it possible to provide a cooling fluid having excellent resistance to aging.

[0027] Indeed, use as an immersion cooling fluid involves prolonged use of the same fluid, up to 5 years or even 10 years. Consequently, it is advantageous for the fluid to be very stable over time, in other words, it is advantageous for it not to degrade over time.

[0028] The inventors have thus discovered that the hydrocarbon fluid defined in the present invention is particularly stable to aging, stability which is notably due to the aromatic content of less than 100 ppm. DETAILED DESCRIPTION OF THE INVENTION

[0029] The invention relates to a use, as a direct immersion cooling fluid, of a composition comprising from 80 to 100% by weight of a hydrocarbon fluid, relative to the total weight of the composition, said hydrocarbon fluid comprising at least 90% by weight of isoparaffins and less than 100 ppm by weight of aromatics, relative to the total weight of the hydrocarbon fluid, said hydrocarbon fluid having a biodegradability of at least 60% at 28 days, measured according to the OECD 30IB standard.

[0030] The present invention also relates to a direct immersion cooling system, comprising: - a bath comprising a composition comprising 80 to 100% by weight of a hydrocarbon fluid, relative to the total weight of the composition, said hydrocarbon fluid comprising at least 90% by weight of isoparaffins and less than 100 ppm by weight of aromatics, relative to the total weight of the hydrocarbon fluid, said hydrocarbon fluid having a biodegradability of at least 60% at 28 days, measured according to the OECD 301B standard, - at least one organ to be cooled partially or totally immersed in the hydrocarbon fluid.

[0031] Finally, the subject of the present invention is a direct immersion cooling method comprising a step of total or partial immersion of at least one member to be cooled in a composition comprising 80 to 100% by weight of a hydrocarbon fluid, relative to the total weight of the composition, said hydrocarbon fluid comprising at least 90% by weight of isoparaffins and less than 100 ppm by weight of aromatics, relative to the total weight of the hydrocarbon fluid, said hydrocarbon fluid having a biodegradability of at least 60% at 28 days, measured according to the OECD 30IB standard.

[0032] As a preliminary point, it will be noted that, in the following description and claims, the expression "between" must be understood as including the limits cited.

[0033] For the purposes of the present invention, the word “paraffins” includes isoparaffins and n-paraffins.

[0034] For the purposes of the present invention, the word “isoparaffins” denotes non-cyclic branched alkanes.

[0035] For the purposes of the present invention, the word “n-paraffins” denotes non-cyclic linear alkanes.

[0036] For the purposes of the present invention, the word “naphthenes” denotes cyclic (non-aromatic) alkanes. Composition :

[0037] According to the invention, the composition comprises from 80 to 100% by weight of a hydrocarbon fluid, relative to the total weight of the composition.

[0038] According to one embodiment, the composition comprises 100% by weight of the hydrocarbon fluid. In this embodiment, the hydrocarbon fluid is used as a cooling fluid.

[0039] According to another embodiment, the composition further comprises from 0.01 to 20% by weight of additives chosen from antioxidants, flame retardants and their mixture, relative to the total weight of the composition.

[0040] According to one embodiment, the composition comprises: - from 85 to 99.99% by weight, preferably from 90 to 99.5% by weight, more preferably from 95% to 99% by weight, of the hydrocarbon fluid, - from 0.01 to 15% by weight, preferably from 0.5 to 10% by weight, more preferably from 1 to 5% by weight of additives,

[0041] relative to the total weight of the composition. Hydrocarbon fluid:

[0042] The hydrocarbon fluid used according to the invention comprises a content of at least 90% by weight of isoparaffins, preferably at least 95% by weight, more preferably at least 98% by weight of isoparaffins, relative to the total weight of the hydrocarbon fluid.

[0043] The hydrocarbon fluid used according to the invention comprises a content of less than or equal to 10% by weight of normal paraffins, preferably less than or equal to 5% by weight, more preferably less than or equal to 2% by weight of normal paraffins, relative to the total weight of the hydrocarbon fluid.

[0044] Preferably, the hydrocarbon fluid used according to the invention has a mass ratio of isoparaffins to normal paraffins of at least 12:1, preferably at least 15:1, more preferably at least 19:1.

[0045] According to one embodiment, the hydrocarbon fluid used according to the invention comprises, relative to the total weight of the hydrocarbon fluid, a weight content of isoparaffins ranging from 90 to 100% and a weight content of normal paraffins ranging from 0 to 10%, preferably from 95 to 100% of isoparaffins and from 0 to 5% of normal paraffins and more preferably from 98% to 100% of isoparaffins and from 0 to 2% of normal paraffins.

[0046] Preferably, the hydrocarbon fluid used according to the invention comprises, relative to the total weight of the hydrocarbon fluid, a content by weight of naphthenic compounds less than or equal to 1%, preferably less than or equal to 0.5% and more preferably less than or equal to 100 ppm.

[0047] According to a preferred embodiment, the hydrocarbon fluid used according to the invention comprises a weight content of isoparaffins ranging from 90 to 100%, a weight content of normal paraffins ranging from 0 to 10% and a weight content of naphthenes less than or equal to 1%, relative to the total weight of the hydrocarbon fluid.

[0048] Preferably, the hydrocarbon fluid used according to the invention comprises a weight content ranging from 95 to 100% of isoparaffins, a weight content ranging from 0 to 5% of normal paraffins and a weight content less than or equal to 0.5% of naphthenes, relative to the total weight of the hydrocarbon fluid.

[0049] More preferably, the hydrocarbon fluid used according to the invention comprises a weight content ranging from 98% to 100% of isoparaffins, from 0 to 2% of normal paraffins and a weight content of naphthenes less than or equal to 100 ppm, relative to the total weight of the hydrocarbon fluid.

[0050] The contents of isoparaffins, normal paraffins and naphthenes can be determined according to any methods known to those skilled in the art, for example by gas chromatography.

[0051] The hydrocarbon fluid used according to the invention comprises less than 100 ppm by weight of aromatics, preferably less than 50 ppm by weight of aromatics, more preferably less than 20 ppm by weight of aromatics, relative to the total weight of the hydrocarbon fluid.

[0052] The aromatic content can be determined according to any methods known to those skilled in the art, for example by UV spectrometry.

[0053] According to a preferred embodiment, the hydrocarbon fluid used according to the invention comprises a weight content of isoparaffins ranging from 90 to 100%, a weight content of normal paraffins ranging from 0 to 10%, a weight content of naphthenes less than or equal to 1% and a weight content of aromatic compounds less than or equal to 100 ppm. Preferably, the hydrocarbon fluid used according to the invention comprises a weight content ranging from 95 to 100% of isoparaffins, from 0 to 5% of normal paraffins, a weight content of naphthenes less than or equal to 0.5% and a weight content of aromatic compounds less than or equal to 50 ppm. Preferably also the hydrocarbon fluid used according to the invention comprises a weight content ranging from 95 to 100% of isoparaffins, from 0 to 5% of normal paraffins and a weight content of aromatic compounds less than or equal to 100 ppm.More preferably, the hydrocarbon fluid used according to the invention comprises a weight content ranging from 98% to 100% of isoparaffins, from 0 to 2% of normal paraffins, a weight content of naphthenes less than or equal to 100 ppm and a weight content of aromatic compounds less than or equal to 100 ppm.

[0054] The hydrocarbon fluid used according to the invention also preferably has an extremely low content by weight of sulfur compounds, typically less than or equal to 5 ppm, preferably less than or equal to 3 ppm and more preferably less than or equal to 0.5 ppm at a level too low to be detected using conventional low-sulfur analyzers.

[0055] The hydrocarbon fluid used according to the invention also preferably has a flash point greater than or equal to 110°C, preferably greater than or equal to 120°C and more preferably greater than or equal to 140°C according to the ASTM D93 standard. A high flash point, typically greater than 110°C, makes it possible in particular to overcome safety problems during storage and transport while avoiding excessive flammability of the hydrocarbon fluid.

[0056] The hydrocarbon fluid used according to the invention also preferably has a vapor pressure at 20°C less than or equal to 0.01 kPa.

[0057] According to one embodiment, the hydrocarbon fluid used according to the invention also preferably has a flash point greater than or equal to 110°C according to the ASTM D93 standard and a vapor pressure at 20°C less than or equal to 0.OlkPa.

[0058] Preferably, the hydrocarbon fluid used according to the invention has a flash point greater than or equal to 120°C and a vapor pressure at 20°C less than or equal to 0.01 kPa.

[0059] And more preferably, the hydrocarbon fluid used according to the invention has a flash point greater than or equal to 140°C and a vapor pressure at 20°C less than or equal to 0.01 kPa.

[0060] The hydrocarbon fluid used according to the invention also preferably has a kinematic viscosity at 40°C less than or equal to 5 cSt, preferably less than or equal to 4 cSt, measured according to the ASTM D445 standard.

[0061] Preferably, the hydrocarbon fluid used according to the invention has an initial boiling point and a final boiling point in the range from 200 to 400°C, preferably from 240 to 350°C, more preferably from 250 to 340°C.

[0062] Boiling points can be determined according to ASTM D86.

[0063] Preferably, the difference between the final boiling point and the initial point boiling range from 10°C to 80°C, preferably from 20°C to 50°C.

[0064] According to a particularly preferred embodiment, the hydrocarbon fluid used according to the invention comprises at least 95% by weight of isoparaffins and less than 100 ppm by weight of aromatics, and has an initial boiling point and a final boiling point in the range from 200 to 400°C.

[0065] According to a particularly preferred embodiment, the hydrocarbon fluid used according to the invention comprises at least 95% by weight of isoparaffins and less than 100 ppm by weight of aromatics, and has an initial boiling point and a final boiling point in the range from 250 to 340°C.

[0066] According to a particularly preferred embodiment, the hydrocarbon fluid used according to the invention comprises at least 95% by weight of isoparaffins and less than 100 ppm by weight of aromatics, and has an initial boiling point and a final boiling point in the range from 200 to 400°C, the difference between the final boiling point and the initial boiling point ranging from 10°C to 80°C.

[0067] According to a particularly preferred embodiment, the hydrocarbon fluid used according to the invention comprises at least 95% by weight of isoparaffins and less than 100 ppm by weight of aromatics, and has an initial boiling point and a final boiling point in the range from 250 to 340°C, the difference between the final boiling point and the initial boiling point ranging from 10°C to 80°C.

[0068] According to a particularly preferred embodiment, the hydrocarbon fluid put in work according to the invention comprises at least 95% by weight of isoparaffins and less than 100 ppm by weight of aromatics, and has an initial boiling point and a final boiling point in the range of 250 to 340°C, the difference between the final boiling point and the initial boiling point ranging from 20°C to 50°C.

[0069] According to one embodiment, the hydrocarbon fluid used according to the invention comprises, relative to the total weight of the hydrocarbon fluid: - from 20 to 80% by weight of C15 isoparaffins and from 20 to 80% by weight of C16 isoparaffins, said fluid then being able to comprise isoparaffins comprising 14 carbon atoms or less and / or isoparaffins comprising 17 carbon atoms or more; or - from 3 to 20% by weight of C15 isoparaffins, from 20 to 70% by weight of C16 isoparaffins, from 5 to 40% by weight of C17 isoparaffins, and from 5 to 40% by weight of C18 isoparaffins, said fluid possibly comprising isoparaffins having 14 carbon atoms or less and / or isoparaffins having 19 carbon atoms or more; or - from 5 to 40% by weight of C17 isoparaffins and from 60 to 95% by weight of C18 isoparaffins, said fluid possibly comprising isoparaffins comprising 16 carbon atoms or less and / or isoparaffins comprising 19 carbon atoms or more.

[0070] According to a particular embodiment, the hydrocarbon fluid used according to the invention comprises, relative to the total weight of the hydrocarbon fluid: - from 30 to 60% by weight of C15 isoparaffins and from 30 to 60% by weight of C16 isoparaffins, said fluid possibly comprising isoparaffins comprising 14 carbon atoms or less and / or isoparaffins comprising 17 carbon atoms or more; or - from 5 to 15% by weight of C15 isoparaffins, from 30 to 60% by weight of C16 isoparaffins, from 10 to 30% by weight of C17 isoparaffins, and from 10 to 30% by weight of C18 isoparaffins, said fluid possibly comprising isoparaffins having 14 carbon atoms or less and / or isoparaffins having 19 carbon atoms or more; or - from 10 to 30% by weight of C17 isoparaffins and from 60 to 90% by weight of C18 isoparaffins, said fluid possibly comprising isoparaffins comprising 16 carbon atoms or less and / or isoparaffins comprising 19 carbon atoms or more.

[0071] The expression “CX isoparaffins” designates isoparaffins comprising X carbon atoms.

[0072] According to one embodiment, the hydrocarbon fluid used according to the invention has a biogenic carbon content of at least 90% by weight, preferably of at least 95% by weight, more preferably at least 97% by weight, relative to the total weight of carbon atoms in the hydrocarbon fluid.

[0073] The biogenic carbon content can be determined according to ASTM D6866 of 2020.

[0074] According to one embodiment, the hydrocarbon fluid used according to the invention comprises from 5 to 15% by weight of C15 isoparaffins, from 30 to 60% by weight of C16 isoparaffins, from 10 to 30% by weight of C17 isoparaffins, and from 10 to 30% by weight of C18 isoparaffins and has an aromatic content of less than 100 ppm by weight, relative to the total weight of the hydrocarbon fluid.

[0075] According to one embodiment, the hydrocarbon fluid used according to the invention has an initial boiling point and a final boiling point in the range from 240 to 300°C and comprises from 5 to 15% by weight of C15 isoparaffins, from 30 to 60% by weight of C16 isoparaffins, from 10 to 30% by weight of C17 isoparaffins, and from 10 to 30% by weight of C18 isoparaffins and has an aromatic content of less than 100 ppm by weight, relative to the total weight of the hydrocarbon fluid.

[0076] According to one embodiment, the hydrocarbon fluid used according to the invention comprises from 10 to 30% by weight of C17 isoparaffins and from 60 to 90% by weight of C18 isoparaffins and has an aromatic content of less than 100 ppm by weight, relative to the total weight of the hydrocarbon fluid.

[0077] According to one embodiment, the hydrocarbon fluid used according to the invention has an initial boiling point and a final boiling point in the range from 260 to 340°C and comprises from 10 to 30% by weight of C17 isoparaffins and from 60 to 90% by weight of C18 isoparaffins and has an aromatic content of less than 100 ppm by weight, relative to the total weight of the hydrocarbon fluid.

[0078] According to one embodiment, the hydrocarbon fluid used according to the invention comprises from 5 to 15% by weight of C15 isoparaffins, from 30 to 60% by weight of C16 isoparaffins, from 10 to 30% by weight of C17 isoparaffins, and from 10 to 30% by weight of C18 isoparaffins and has an aromatic content of less than 100 ppm by weight, relative to the total weight of the hydrocarbon fluid and said fluid has a biogenic carbon content of at least 95% by weight, relative to the total weight of the carbon atoms of the hydrocarbon fluid.

[0079] According to one embodiment, the hydrocarbon fluid used according to the invention has an initial boiling point and a final boiling point in the range from 240 to 300°C and comprises from 5 to 15% by weight of C15 isoparaffins, from 30 to 60% by weight of C16 isoparaffins, from 10 to 30% by weight of C17 isoparaffins, and from 10 to 30% by weight of C18 isoparaffins and has an aromatic content of less than 100 ppm by weight, relative to the total weight of the hydrocarbon fluid and said fluid has a biogenic carbon content of at least 95% by weight, relative to the total weight of carbon atoms in the hydrocarbon fluid.

[0080] According to one embodiment, the hydrocarbon fluid used according to the invention comprises from 10 to 30% by weight of C17 isoparaffins and from 60 to 90% by weight of C18 isoparaffins and has an aromatic content of less than 100 ppm by weight, relative to the total weight of the hydrocarbon fluid and said fluid has a biogenic carbon content of at least 95% by weight, relative to the total weight of the carbon atoms of the hydrocarbon fluid.

[0081] According to one embodiment, the hydrocarbon fluid used according to the invention has an initial boiling point and a final boiling point in the range from 260 to 340°C and comprises from 10 to 30% by weight of C17 isoparaffins and from 60 to 90% by weight of C18 isoparaffins and has an aromatic content of less than 100 ppm by weight, relative to the total weight of the hydrocarbon fluid and said fluid has a biogenic carbon content of at least 95% by weight, relative to the total weight of the carbon atoms of the hydrocarbon fluid.

[0082] According to one embodiment, the hydrocarbon fluid used according to the invention comprises from 5 to 15% by weight of C15 isoparaffins, from 30 to 60% by weight of C16 isoparaffins, from 10 to 30% by weight of C17 isoparaffins, and from 10 to 30% by weight of C18 isoparaffins and has an aromatic content of less than 50 ppm by weight, relative to the total weight of the hydrocarbon fluid and said fluid has a biogenic carbon content of at least 90% by weight, relative to the total weight of the carbon atoms of the hydrocarbon fluid.

[0083] According to one embodiment, the hydrocarbon fluid used according to the invention comprises from 10 to 30% by weight of C17 isoparaffins and from 60 to 90% by weight of C18 isoparaffins and has an aromatic content of less than 50 ppm by weight, relative to the total weight of the hydrocarbon fluid and said fluid has a biogenic carbon content of at least 90% by weight, relative to the total weight of the carbon atoms of the hydrocarbon fluid.

[0084] The hydrocarbon fluid used according to the invention has a biodegradability of at least 60% at 28 days, measured according to the OECD 301B standard. Thus, typically, the hydrocarbon fluid according to the invention will be said to be “easily biodegradable” or “readily biodegradable” in English.

[0085] In contrast, a product will be said to be “inherently biodegradable” if it has a biodegradability ranging from 20 to less than 60% at 28 days according to the OECD 301 standard, for example according to the OECD 301B standard.

[0086] According to one embodiment, the hydrocarbon fluid used according to the invention has a biodegradability at 28 days of at least 70%, preferably at least 80%, measured according to the OECD 30IB standard.

[0087] Preferably, the hydrocarbon fluid used according to the invention has a biodegradability of at least 60% at 28 days, measured according to the OECD 306 standard. The OECD 306 standard is more restrictive than the OECD 301B standard.

[0088] According to a particularly preferred embodiment, the hydrocarbon fluid used according to the invention comprises at least 95% by weight of isoparaffins and less than 100 ppm by weight of aromatics, and has an initial boiling point and a final boiling point in the range from 200 to 400°C, said hydrocarbon fluid having a biodegradability of at least 60% at 28 days, measured according to the OECD 301B standard.

[0089] According to a particularly preferred embodiment, the hydrocarbon fluid used according to the invention comprises at least 95% by weight of isoparaffins and less than 100 ppm by weight of aromatics, and has an initial boiling point and a final boiling point in the range from 250 to 340°C, said hydrocarbon fluid having a biodegradability of at least 60% at 28 days, measured according to the OECD 301B standard.

[0090] According to a particularly preferred embodiment, the hydrocarbon fluid used according to the invention comprises at least 95% by weight of isoparaffins and less than 100 ppm by weight of aromatics, and has an initial boiling point and a final boiling point in the range from 250 to 340°C, the difference between the final boiling point and the initial boiling point ranging from 20°C to 50°C, said hydrocarbon fluid having a biodegradability of at least 60% at 28 days, measured according to the OECD 30IB standard.

[0091] According to one embodiment, the hydrocarbon fluid used according to the invention comprises from 5 to 15% by weight of C15 isoparaffins, from 30 to 60% by weight of C16 isoparaffins, from 10 to 30% by weight of C17 isoparaffins, and from 10 to 30% by weight of C18 isoparaffins and has an aromatic content of less than 100 ppm by weight, relative to the total weight of the hydrocarbon fluid, said hydrocarbon fluid having a biodegradability of at least 60% at 28 days, measured according to the OECD 30IB standard.

[0092] According to one embodiment, the hydrocarbon fluid used according to the invention comprises from 10 to 30% by weight of C17 isoparaffins and from 60 to 90% by weight of C18 isoparaffins and has an aromatic content of less than 100 ppm by weight, relative to the total weight of the hydrocarbon fluid, said hydrocarbon fluid having a biodegradability of at least 60% at 28 days, measured according to the OECD 301B standard.

[0093] According to a particularly preferred embodiment, the hydrocarbon fluid used according to the invention comprises at least 95% by weight of isoparaffins and less than 50 ppm by weight of aromatics, and has an initial boiling point and a boiling point final boiling point in the range of 200 to 400°C, said hydrocarbon fluid having a biodegradability of at least 60% at 28 days, measured according to OECD standard 301B.

[0094] According to a particularly preferred embodiment, the hydrocarbon fluid used according to the invention comprises at least 95% by weight of isoparaffins and less than 50 ppm by weight of aromatics, and has an initial boiling point and a final boiling point in the range from 250 to 340°C, said hydrocarbon fluid having a biodegradability of at least 60% at 28 days, measured according to the OECD 301B standard.

[0095] According to a particularly preferred embodiment, the hydrocarbon fluid used according to the invention comprises at least 95% by weight of isoparaffins and less than 50 ppm by weight of aromatics, and has an initial boiling point and a final boiling point in the range from 250 to 340°C, the difference between the final boiling point and the initial boiling point ranging from 20°C to 50°C, said hydrocarbon fluid having a biodegradability of at least 60% at 28 days, measured according to the OECD 30IB standard.

[0096] According to one embodiment, the hydrocarbon fluid used according to the invention comprises from 5 to 15% by weight of C15 isoparaffins, from 30 to 60% by weight of C16 isoparaffins, from 10 to 30% by weight of C17 isoparaffins, and from 10 to 30% by weight of C18 isoparaffins and has an aromatic content of less than 50 ppm by weight, relative to the total weight of the hydrocarbon fluid, said hydrocarbon fluid having a biodegradability of at least 60% at 28 days, measured according to the OECD 30IB standard.

[0097] According to one embodiment, the hydrocarbon fluid used according to the invention comprises from 10 to 30% by weight of C17 isoparaffins and from 60 to 90% by weight of C18 isoparaffins and has an aromatic content of less than 50 ppm by weight, relative to the total weight of the hydrocarbon fluid, said hydrocarbon fluid having a biodegradability of at least 60% at 28 days, measured according to the OECD 301B standard. Process for obtaining the hydrocarbon fluid:

[0098] The hydrocarbon fluid used according to the invention can be obtained in the following way. The hydrocarbon fluid used according to the invention is a hydrocarbon cut typically resulting from the conversion of biomass.

[0099] By biomass conversion product is meant a hydrocarbon cut produced from raw materials of biological origin. The raw materials of biological origin may be chosen from vegetable oils, animal fats, fish oils and mixtures thereof.

[0100] Preferably, the hydrocarbon fraction of biological origin is obtained by a process comprising hydrodeoxygenation (HDO) and isomerization (ISO) steps. The hydrodeoxygenation (HDO) step leads to the decomposition of the structures of the biological esters or triglyceride constituents, to the elimination of oxygenated, phosphorus and sulfur compounds and to the hydrogenation of the olefinic bonds. The product resulting from the hydrodeoxygenation reaction is then isomerized. A fractionation step may preferably follow the hydrodeoxygenation and isomerization steps. Advantageously, the fractions of interest are then subjected to hydrotreatment and then distillation steps in order to obtain the specifications of the desired hydrocarbon fluid according to the invention.

[0101] This HDO / ISO process is carried out on a raw biological feedstock, also called biomass or raw material of biological origin, selected from the group consisting of vegetable oils, animal fats, fish oils and their mixture. Suitable raw materials of biological origin are, for example, rapeseed oil, canola oil, tall oil, sunflower oil, soybean oil, hemp oil, olive oil, linseed oil, mustard oil, palm oil, peanut oil, castor oil, coconut oil, animal fats such as tallow, recycled edible fats, raw materials from genetic engineering, and biological raw materials produced from microorganisms such as algae and bacteria. Condensation products, esters or other derivatives obtained from raw biological materials can also serve as raw materials.

[0102] Preferably, the raw material of biological origin is an ester or a triglyceride derivative. This material is first subjected to a hydrodeoxygenation (HDO) step to decompose the structure of the constituent esters or triglycerides and eliminate the oxygenated, phosphorus and sulfur compounds concomitantly with the hydrogenation of the olefinic bonds. This hydrodeoxygenation (HDO) step of the raw material of biological origin is followed by an isomerization of the product thus obtained leading to the branching of the hydrocarbon chain and to an improvement in the properties of the paraffin at low temperatures.

[0103] During the HDO step, the hydrogen and the raw material of biological origin are passed over a hydrodeoxygenation catalytic bed simultaneously or countercurrently. During the HDO step, the pressure and temperature are between 20 and 150 bars and between 200 and 500°C respectively. Conventional and known hydrodeoxygenation catalysts are used during this step. Optionally, the raw material of biological origin may be subjected to pre-hydrogenation under mild conditions to avoid secondary reactions of the double bonds before the HDO step. After the hydrodeoxygenation step, the product resulting from the reaction is subjected to an isomerization step (ISO) where the hydrogen and the product, and optionally a mixture of n-paraffins, are passed over isomerization catalyst beds simultaneously or countercurrently. During the ISO step, the pressure and temperature are between 20 and 150 bars and between 200 and 500°C respectively. Conventional and known isomerization catalysts are used during this step.

[0104] Additional secondary processes may also be implemented (such as intermediate mixing, trapping or other such processes).

[0105] The product from the HDO / ISO steps can optionally be fractionated in order to obtain the cuts of interest.

[0106] Various HDO / ISO processes are described in the literature. Application WO2014 / 033762 describes a process comprising a pre-hydrogenation step, a hydrodeoxygenation (HDO) step and an isomerization step carried out countercurrently. Patent application EPI728844 describes a process for producing hydrocarbon compounds from a mixture of compounds of plant and animal origin. This process comprises a step of pre-treating the mixture to remove contaminants, such as alkali metal salts, followed by a hydrodeoxygenation (HDO) step and an isomerization step.Patent application EP2084245 describes a process for producing a hydrocarbon mixture that can be used as diesel or in a diesel composition by hydrodeoxygenation of a mixture of biological origin containing fatty acid esters optionally in admixture with free fatty acids, for example vegetable oils such as sunflower oil, rapeseed oil, canola oil, palm oil or pine oil, followed by hydroisomerization on specific catalysts. Patent application EP2368967 describes such a process and the product obtained by this process.

[0107] Advantageously, the raw material of biological origin contains less than 15 ppm of sulfur, preferably less than 8 ppm, preferentially less than 5 ppm and more preferentially less than 1 ppm according to standard EN ISO 20846. Ideally, the feed does not include sulfur as a raw material of biosourced origin.

[0108] The deoxygenated and isomerized feedstock from the HDO / ISO process is then hydrogenated, after having been optionally fractionated in order to obtain a desired boiling range.

[0109] Preferably, the hydrogenation step is a catalytic hydrogenation step at a temperature of 80 to 180°C and at a pressure of 50 to 160 bars of a charge (or cut) of deoxygenated and isomerized biological origin.

[0110] The hydrogen used in the hydrogenation unit is typically highly purified hydrogen. Highly purified means hydrogen with a purity of, for example, greater than 99%, although other grades may also be used.

[0111] The hydrogenation step is carried out using catalysts. The catalysts Typical hydrogenation substrates can be either bulk or supported and may include the following metals: nickel, platinum, palladium, rhenium, rhodium, nickel tungstate, nickel-molybdenum, molybdenum, cobalt-molybdenum. Supports may be silica, alumina, silica-alumina, or zeolites.

[0112] A preferred catalyst is a nickel-based catalyst on an alumina support whose specific surface area preferably varies from 100 to 200 m2 / g of catalyst or a nickel-based bulk catalyst. The hydrogenation conditions are typically as follows: - Pressure: 50 to 160 bars, preferably 80 to 150 bars and more preferably 90 to 120 bars; - Temperature: 80 to 180°C, preferably 120 to 160°C and more preferably 150 to 160°C; - Hourly volumetric speed (WH): 0.2 to 5 hr-1, preferably 0.4 to 3 hr-1 and more preferably 0.5 to 0.8 hr-1; - Hydrogen treatment rate: suitable for the conditions mentioned above and up to 200 Nm3 / tonnes of charge to be treated.

[0113] The temperature in the reactors is typically between 150 and 160°C with a pressure of approximately 100 bars while the hourly volumetric velocity is approximately 0.6 hr-1 with a treatment rate adapted according to the quality of the feedstock to be treated and the parameters of the first hydrogenation reactor.

[0114] The hydrogenation may take place in one or more reactors in series. The reactors may comprise one or more catalytic beds. The catalytic beds are generally fixed catalytic beds.

[0115] The hydrogenation process preferably comprises two or three reactors, preferably three reactors and is more preferably carried out in three reactors in series.

[0116] The first reactor allows the trapping of sulfur compounds and the hydrogenation of essentially all unsaturated compounds and up to about 90% by weight of aromatic compounds. The product from the first reactor contains substantially no sulfur compounds. In the second stage, i.e. in the second reactor, the hydrogenation of the aromatics continues and up to 99% by weight of the aromatics are thereby hydrogenated.

[0117] The third stage in the third reactor is a finishing stage making it possible to obtain aromatic contents of less than 100 ppm, preferably less than 50 ppm, preferentially less than 20 ppm.

[0118] It is possible to use a reactor which has two or three or more catalytic beds. The catalysts may be present in varying or essentially equal amounts in each reactor; for three reactors, the amounts based on weight may for example be 0.05-0.5 / 0.10-0.70 / 0.25-0.85, preferably 0.07-0.25 / 0.15-0.35 / 0.4-0.78 and more preferably 0.10-0.20 / 0.20-0.32 / 0.48-0.70.

[0119] It is also possible to use one or two hydrogenation reactors instead of three.

[0120] It is also possible for the first reactor to be composed of twin reactors operated alternatively. This mode of operation notably allows for easier loading and unloading of the catalysts: when the first reactor comprises the saturated catalyst first (substantially all the sulfur is trapped on and / or in the catalyst) it must be changed often.

[0121] A single reactor can also be used in which two, three or more catalytic beds are installed.

[0122] It may be necessary to insert quench boxes (in the English sense of "reaction smothering") in the recycle system or between reactors to cool the effluents from one reactor to another or from one catalytic bed to another in order to control the temperatures and the hydrothermal balance of each reaction. In a preferred embodiment, there are no cooling or smothering intermediates.

[0123] According to one embodiment, the product from the process and / or the separated gases are at least partly recycled into the feed system of the hydrogenation reactors. This dilution contributes to maintaining the exothermicity of the reaction within controlled limits, in particular in the first stage. The recycling also allows heat exchange before the reaction and also better temperature control.

[0124] The effluent from the hydrogenation unit mainly contains the hydrogenated product and hydrogen. Flash separators are used to separate the effluents into the gas phase, mainly the residual hydrogen, and the liquid phase, mainly the hydrogenated hydrocarbon cuts. The process can be carried out using three flash separators, one at high pressure, one at intermediate pressure and one at low pressure very close to atmospheric pressure.

[0125] The hydrogen gas that is collected at the top of the flash separators can be recycled into the feed system of the hydrogenation unit or at different levels in the hydrogenation units between the reactors.

[0126] According to one embodiment, the final product is separated at atmospheric pressure. It then feeds directly into a vacuum fractionation unit. Preferably, the fractionation will be carried out at a pressure of between 10 and 50 mbar and more preferably at approximately 30 mbar.

[0127] The fractionation may be carried out in such a way that it is possible to simultaneously remove various hydrocarbon fluids from the fractionation column and to have their boiling temperature can be predetermined.

[0128] By adapting the feedstock through its initial and final boiling points, the hydrogenation reactors, separators and fractionation unit can therefore be directly connected without the need to use intermediate tanks. This integration of hydrogenation and fractionation allows for optimized thermal integration associated with a reduction in the number of devices and energy savings.

[0129] Thus, according to one embodiment of the invention, the hydrocarbon fluid used in the invention is obtained by a process comprising a step of catalytic hydrogenation of a biomass which has been hydrodeoxygenated and hydroisomerized, said hydrogenation step being carried out at a temperature ranging from 80 to 180°C and at a pressure of 50 to 160 bars, preferably at a temperature ranging from 120 to 160°C and at a pressure ranging from 80 to 150 bars, more preferably at a temperature ranging from 150 to 160°C and at a pressure ranging from 90 to 120 bars.

[0130] According to a particular embodiment, the hydrocarbon fluid used in the invention is obtained by a process comprising: - a hydrodeoxygenation step followed by a hydroisomerization step of a biomass in order to obtain a hydrodeoxygenated and hydroisomerized biomass, - a step of catalytic hydrogenation of the hydrodeoxygenated and hydroisomerized biomass, said hydrogenation step being carried out at a temperature ranging from 80 to 180°C and at a pressure of 50 to 160 bars, preferably at a temperature ranging from 120 to 160°C and at a pressure ranging from 80 to 150 bars, more preferably at a temperature ranging from 150 to 160°C and at a pressure ranging from 90 to 120 bars,

[0131] the biomass preferably being chosen from vegetable oils, animal fats, fish oils and their mixtures.

[0132] The hydrocarbon fluid used according to the invention is ideally derived from the processing of raw materials of biological origin. The term "biogenic carbon" or "bio-carbon" indicates that the carbon is of natural origin and comes from a biomaterial, as indicated below. The bio-carbon content, the biogenic carbon content and the biomaterial content are expressions indicating the same value. A material of renewable origin or biomaterial is an organic material in which the carbon comes from CO2 fixed recently (on a human scale) by photosynthesis from the atmosphere. A biomaterial (100% natural carbon) has a 14C / 12C isotopic ratio greater than 10 12, typically about 1.2 x 10 12, while a fossil material has a zero ratio. Indeed, the isotopic 14C formed in the atmosphere is then integrated by photosynthesis, according to a scale of a time of a few decades at most. The half-life of 14C is 5730 years. Thus, materials resulting from photosynthesis, namely plants in general, necessarily have a maximum content of the 14C isotope. Additives

[0133] According to one embodiment, the composition used as cooling fluid comprises, in addition to the hydrocarbon fluid, one or more additives.

[0134] Among the additives that can be implemented, we can cite antioxidants, flame retardants and their mixture.

[0135] According to one embodiment, the composition comprises at least one flame retardant additive. The flame retardant additive may be chosen from halogenated compounds, phosphorus compounds, metal hydroxides and mixtures thereof.

[0136] According to one embodiment, the flame retardant additive corresponds to formula (I):

[0137] RF-L-RH (I)

[0138] in which: - RF is a hydrocarbon group, in particular comprising from 1 to 22, preferably from 1 to 20, even more preferably from 1 to 16 carbon atoms, - RH is a hydrocarbon group, in particular comprising from 1 to 22, preferably from 1 to 20, even more preferably from 1 to 16 carbon atoms, and - L is a linker chosen from the following groups: -CH2-, -CH=CH-, -O-, -S- or -PO4-,

[0139] RF and / or RH may also comprise at least one element chosen from elements of the halogen class such as preferably fluorine, bromine and / or chlorine.

[0140] According to one embodiment, the composition is free of perfluorooctyl bromide.

[0141] If they are used in the composition, the flame retardant(s) preferably represent from 0.01 to 20% by weight of the weight of the composition, preferably from 1 to 10% by weight of the weight of the composition.

[0142] According to one embodiment, the composition comprises at least one antioxidant additive. The antioxidant additive generally makes it possible to delay the degradation of the composition in service. This degradation can in particular result in the formation of deposits, the presence of sludge or an increase in the viscosity of the composition.

[0143] Antioxidant additives act in particular as radical inhibitors or hydroperoxide destroyers. Among the commonly used antioxidant additives, we may cite phenolic type antioxidant additives, amine type antioxidant additives, phosphosulfur antioxidant additives. Some of these antioxidant additives, for example phosphosulfur antioxidant additives, may be ash-generating. Phenolic antioxidant additives may be ash-free or in the form of neutral or basic metal salts. The antioxidant additives may in particular be chosen from sterically hindered phenols, sterically hindered phenol esters and sterically hindered phenols comprising a thioether bridge, diphenylamines, diphenylamines substituted by at least one C1-C12 alkyl group, and their mixture.

[0144] According to one embodiment, the sterically hindered phenols are chosen from compounds comprising a phenol group of which at least one vicinal carbon of the carbon carrying the alcohol function is substituted by at least one C1-C10 alkyl group, preferably a C1-C6 alkyl group, preferably a C4 alkyl group, preferably by the tert-butyl group.

[0145] Amino compounds are another class of antioxidant additives that can be used, optionally in combination with phenolic antioxidant additives. Examples of amine compounds are aromatic amines, for example aromatic amines of formula NR4R5R6 in which R4 represents an aliphatic group or an aromatic group, optionally substituted, R5 represents an aromatic group, optionally substituted, R6 represents a hydrogen atom, an alkyl group, an aryl group or a group of formula R7S(O)zR8 in which R7 represents an alkylene group or an alkenylene group, R8 represents an alkyl group, an alkenyl group or an aryl group and z represents 0, 1 or 2.

[0146] Sulfurized alkyl phenols or their alkali and alkaline earth metal salts can also be used as antioxidant additives.

[0147] Another class of antioxidant additives is that of copper compounds, for example copper thio- or dithio-phosphates, copper salts of carboxylic acids, dithiocarbamates, sulphonates, phenates, copper acetylacetonates. Copper I and II salts, succinic acid or anhydride salts can also be used.

[0148] If they are used in the composition, the antioxidant(s) preferably represent from 0.01 to 3% by weight of the weight of the composition, preferably from 0.05 to 2% by weight of the weight of the composition.

[0149] Use of the hydrocarbon fluid or composition:

[0150] The hydrocarbon fluid or composition is used as a direct immersion cooling fluid, in particular by direct immersion of data center components.

[0151] Preferably, the cooling is single-phase direct immersion cooling. In other words, typically, the hydrocarbon fluid (or composition) does not undergo a phase change during the cooling process.

[0152] The data center organs can be, for example, servers, computers including in particular microprocessors. Cooling system

[0153] The present invention also relates to a system for cooling at least one member by direct immersion, comprising: - a bath comprising the composition defined in the present invention, - said at least one organ partially or totally immersed in the com position.

[0154] The immersion can be total if the entire volume of the organ is immersed in the hydrocarbon fluid.

[0155] The immersion may be partial if it is not the entire volume of the organ which is immersed in the hydrocarbon fluid, but only a part.

[0156] Preferably, the organ to be cooled is an organ of a data center, for example a server or a computer.

[0157] The composition comprising the hydrocarbon fluid may be static or circulating in the cooling system.

[0158] The cooling system may further comprise a heat exchange system, in which the cooling fluid which has been heated by the member in the bath, is cooled before being reintroduced into the bath.

[0159] According to this embodiment, the hydrocarbon fluid or the composition can then be circulated between the bath comprising at least one member to be cooled and the heat exchange system.

[0160] The heat exchange system may be connected to a water or air circuit, the water or air then allowing the hydrocarbon fluid or composition to be cooled, before it is reintroduced into the bath to perform its role as a cooling fluid.

[0161] The circulation of the cooling fluid can be ensured by a pump system.

[0162] The heat recovered from the composition comprising the hydrocarbon fluid during the heat exchange can optionally be recovered and used, for example, to heat a building. Cooling process

[0163] The present invention also relates to a method for cooling at least one member by direct immersion comprising a step of total immersion or partial of said at least one organ in the composition defined in the present invention.

[0164] Typically, the composition is placed in a bath and the organ is totally or partially immersed in the composition within said bath.

[0165] Preferably, the organ to be cooled is an organ of a data center, for example a server or a computer.

[0166] The cooling method according to the invention can be implemented in the cooling system according to the invention.

[0167] The cooling method according to the invention may further comprise a step of cooling the composition previously heated during immersion in the bath. This step of cooling the composition may be implemented using a heat exchanger, external to the bath, with a water or air circuit. According to one embodiment, the method according to the invention may further comprise, following the step of cooling the composition, a step of recovering heat from the composition, said recovered heat possibly being used for example to heat a building. EXAMPLES

[0168] In the remainder of this description, examples are given for the purpose of illustrating the present invention and are not intended in any way to limit its scope.

[0169] Three hydrocarbon fluids are prepared according to a process as described in the present invention, by HDO / ISO of a biomass followed by a hydrogenation step.

[0170] Table 1 lists the physicochemical properties of hydrocarbon fluids.

[0171] [Tableauxl] Fluid 1 Fluid 2 Fluid 3 % iso paraffins (wt / wt) 98.9 95.1 96.2 % n-paraffins (wt / wt) 1.1 4.9 3.8 % naphthenics (wt / wt) 0 0 0 Aromatics (ppm) <20 <20 <20 Sulfur (ppm) 0.1 0.1 0.11 C13 (iso) 0.66 0 0 C14 (iso) 4.15 0.12 0 C15 (iso) 48.35 11.45 0 C16 (iso) 42.80 47.89 1.58 C17 (iso) 2.52 18.57 14.17 Cl8 (iso) 0.38 17.07 79.69 C19 (iso) 0 0 0.12 C20 (iso) 0 0 0.38 C27 (iso) 0 0 0.29 Amount of biogenic carbons (%) 97 97 98 Initial boiling point (°C) 247.0 259.5 293.6 Boiling point 5% (°C) 255.7 270.2 296.7 Boiling point 50% (°C) 258.9 274.5 298.5 Boiling point 95% (°C) 266.8 286.4 305.3 Final boiling point (°C) 269.0 287.5 324.1 Biodegradability (28 days) (%) 89 89 89 Refractive index at 20°C 1.4336 1.4357 1.4394 density at 15°C (kg / m3) 776.4 780.3 787.2 Flash point (°C) 115 125 149 Pour point (°C) -81 -60 -45 Kinematic viscosity at 40°C (cSt) 2.49 2.94 3.87 Vapour pressure at 20°C (kPa) <0.01 <0.01 <0.01 Specific heat (at °C in J / (kg.K)) 30.3 / 2154 74.8 / 2336 31.3 / 2202 74.8 / 2324 31.3 / 2185 89.7 / 2377 , 129.2 / 2540 129.2 / 2503 158.9 / 2695 Thermal conductivity (at °C in W / (mK)) 28 / 0.130 73 / 0.125 128 / 0.124 27 / 0.135 73 / 0.128 127 / 0.126 23 / 0.138 88 / 0.137 158 / 0.127

[0172] The following standards and methods were used to measure the above properties:

[0173] - flash point: EN ISO 2719, - density at 15°C: EN ISO 1185,

[0174] - pour point: EN ISO 3016, - viscosity at 40°C: EN ISO 3104, - Boiling point: ASTM D86 - biodegradability: OECD 30IB method,

[0175] - pour point: ASTM D5950.

[0176] Specific heat is measured using a DSC calorimeter (DSC NETZSCH 204 Phoenix), which complies with ISO 113587, ASTM E1269, ASTM E968, ASTM E793, ASTM D3895, ASTM D3417, ASTM D3418, DIN 51004, DIN 51007 and DIN 53765.

[0177] Thermal conductivity is determined by the following method:

[0178] A device consisting of two aluminum tubes, one inner and one outer, was used. The fluid to be measured is placed in the annular space between the two tubes. An energy pulse (Dirac type) is applied to the inner tube and the temperature is measured on the outer tube, which makes it possible to obtain a thermogram.

[0179] Knowing the thermal diffusivity, the density and the specific heat of the two layers of the two aluminum tubes as a function of the temperature, and knowing the density and the specific heat of the fluid to be analyzed, we can deduce the thermal conductivity of the fluid as a function of the temperature.

[0180] The device is first calibrated with a reference sample, SERIOLA 1510 (heat transfer fluid) at different temperatures. The different thermal properties were measured separately beforehand.

[0181] The sample (fluid to be measured) is mixed and introduced (using a syringe) into the annular space between the two tubes. The charged device is then placed in a temperature-controlled chamber.

[0182] For each temperature measurement, the following procedure is followed. The sample is stabilized at a given temperature. Then light flashes are applied to the inner face of the inner tube and the temperature rise of the outer face of the outer tube is recorded over time.

[0183] Based on the average values ​​obtained with at least 3 measurements at each tem- Given temperature, thermal conductivity is calculated.

[0184] In summary, the hydrocarbon fluid has excellent thermal properties as well as a very low aromatic content, which makes it particularly advantageous for cooling data center components by direct immersion. The very low aromatic content makes it possible to improve aging, to have better resistance to aging, which is very useful for this type of application where the same fluid can be used for 5 years or even 10 years.

Claims

Claims

1. Use, as a direct immersion cooling fluid, of a composition comprising 100% by weight of a hydrocarbon fluid, said hydrocarbon fluid comprising at least 90% by weight of a hydrocarbon fluid comprising at least 90% by weight of isoparaffins and less than 100 ppm by weight of aromatics, relative to the total weight of the hydrocarbon fluid, said hydrocarbon fluid having a biodegradability at 28 days measured according to the OECD 301B standard greater than or equal to 60%.

2. Use according to claim 1, in which the hydrocarbon fluid comprises, relative to the total weight of the hydrocarbon fluid: - at least 95% by weight of isoparaffins, and / or - at most 5% by weight of normal paraffins, and / or - at most 1% by weight of naphthenes, and / or - less than 50 ppm by weight of aromatics.

3. Use according to claim 1 or 2, in which the hydrocarbon fluid has: - a flash point greater than or equal to 110°C, preferably greater than or equal to 120°C, or even greater than or equal to 140°C according to standard ASTM D93, and / or - a kinematic viscosity at 40°C less than or equal to 5 cSt, preferably less than or equal to 4 cSt.

4. Use according to any one of claims 1 to 3, wherein the hydrocarbon fluid has: - an initial boiling point and a final boiling point in the range from 200 to 400°C, preferably from 240 to 350°C, more preferably from 250 to 340°C, and / or - a difference between the final boiling point and the initial boiling point ranging from 10°C to 80°C, preferably from 20°C to 50°C.

5. Use according to any one of claims 1 to 4, in which the hydrocarbon fluid comprises, relative to the total weight of the hydrocarbon fluid: - from 30 to 60% by weight of C15 isoparaffins and from 30 to 60% by weight of C16 isoparaffins, or - from 5 to 15% by weight of C15 isoparaffins, from 30 to 60% by weight of C16 isoparaffins, from 10 to 30% by weight of C17 isoparaffins, and from 10 to 30% by weight of C18 isoparaffins, or - from 10 to 30% by weight of C17 isoparaffins and from 60 to 90% by weight of C18 isoparaffins.

6. Use, as a direct immersion cooling fluid for at least one component of a data center, of a composition comprising 80 to 100% by weight of a hydrocarbon fluid, relative to the total weight of the composition, said hydrocarbon fluid comprising at least 90% by weight of a hydrocarbon fluid comprising at least 90% by weight of isoparaffins and less than 100 ppm by weight of aromatics, relative to the total weight of the hydrocarbon fluid, said hydrocarbon fluid having a biodegradability at 28 days measured according to the OECD 301B standard greater than or equal to 60%.

7. Use according to claim 6, wherein the composition further comprises, relative to the total weight of the composition, from 0.01 to 20% by weight of additives preferably chosen from antioxidants, flame retardants and their mixture.

8. Direct immersion cooling system, comprising: - a bath comprising a composition comprising 80 to 100% by weight of a hydrocarbon fluid, relative to the total weight of the composition, said hydrocarbon fluid comprising at least 90% by weight of isoparaffins and less than 100 ppm by weight of aromatics, relative to the total weight of the hydrocarbon fluid, said hydrocarbon fluid having a biodegradability at 28 days measured according to the OECD 301B standard greater than or equal to 60%, - at least one member to be cooled partially or totally immersed in the composition, in which the organ to be cooled is an organ of a data center.

9. A cooling system according to claim 8, wherein the hydrocarbon fluid is as defined in any one of claims 2 to 5.

10. A cooling system according to any one of claims 8 to 9, wherein the composition is as defined in claim 6 or claim 7.

11. A method of direct immersion cooling comprising a step of total or partial immersion of at least one member to be cooled in a composition comprising 80 to 100% by weight of a hydrocarbon fluid, relative to the total weight of the composition, said hydrocarbon fluid comprising at least 90% by weight of isoparaffins and less than 100 ppm by weight of aromatics, relative to the total weight of the hydrocarbon fluid, said hydrocarbon fluid having a biodegradability at 28 days measured according to the OECD 301B standard greater than or equal to 60%, relative to the total weight of carbon atoms, in which the member to be cooled is a member of a data center.

12. A cooling method according to claim 11, wherein the hydrocarbon fluid is as defined in any one of claims 2 to 5.

13. A cooling method according to any one of claims 11 to 12, wherein the composition is as defined in claim 6 or claim 7.