Single-phase heat transfer compositions and uses thereof

Abstract

The present disclosure provides single-phase heat transfer compositions including at least one compound of formula I: CF3(CF2)nCX=CX(CF2)nCF3 (I) in a form of any one of its isomers or a mixture thereof, where: n is an integer in a range of from 1 to 5, when n is 1 or 2, X is CF3, and when n is 3, 4, or 5, X is H. The present disclosure also provides for methods of use for the single-phase heat transfer compositions. The single-phase heat transfer compositions are particularly useful in cooling and / or heating applications.

Description

TITLE OF THE INVENTIONSINGLE-PHASE HEAT TRANSFER COMPOSITIONS AND USES THEREOFFIELD OF DISCLOSURE

[0001] The present disclosure is in the field of single-phase heat transfer compositions. These single-phase heat transfer compositions are particularly useful in cooling and / or heating applications.BACKGROUND

[0002] Immersion cooling has become one of the emerging technologies for thermal management of electronic / electrical equipment, such as data center servers and electric vehicle battery packs, due to its superior heat removal capabilities compared to traditional air cooling. Immersion cooling enables 10-1000 times higher rate of heat removal than air cooling.

[0003] In two-phase immersion cooling (2-PIC), a dielectric liquid boils when in direct contact with hot components and turns into vapor, which then rises and condenses in a heat exchanger. Even though there is no need for pumps for the cooling process, a small auxiliary pump is still used to circulate the fluid through a filter. Although 2PIC provides more than 10 times higher heat removal than conventional single-phase immersion cooling (1 PIC), evaporation fluid losses, vapor management, and high pressure can become a challenge for some applications, which may not require such high heat removal capabilities. For such application, it can be simpler and more convenient to use 1 PIC in which a higher boiling point fluid is used.

[0004] Most conventional single-phase immersion fluids used today are oils such as synthetic or refined hydrocarbons, esters, or other petroleum products derivatives. Although oils tend to have lower cost and excellent dielectric properties, they are combustible. Higher viscosity oils may be used to improve safety with a higher flash point. However, higher viscosity oils are difficult to pump relative to a lower viscosity fluid. Their high viscosity and low vapor pressure can also make for messy server maintenance in data centers. Even with a higher viscosity, oils can still pose a fire hazard and additional risk to data centers and EV batteries, which representsignificant financial investments and liability. They do, however, have good heat transfer properties, such as high specific heat and thermal conductivity. These good heat transfer properties are at odds with their higher viscosities, requiring higher pump power as compared to fluorinated based immersion fluids.

[0005] On the other hand, fluorinated single-phase immersion fluids, such as hydrofluorocarbons (HFC’s), perfluorocarbons (PFC’s), hydrofluoroethers (HFE’s), perfluoropolyether (PFPE’s), hydrofluoroolefins (HFO’s), hydrofluorochloroolefins (HFCO’s) and perfluoroolefins (PFO’s), typically have significantly lower viscosity, are non-flammable, and are non-combustible. However, commercially available fluorinated single-phase immersion fluids have high global warming potential (GWP) and are not acceptable as long-term cooling solutions.

[0006] Accordingly, there is a need for an ultra-low GWP, non-flammable, singlephase immersion fluid having low viscosity, excellent dielectric and heat transfer properties, good oxidation resistance, and good fluid stability and chemical compatibility with typical materials of construction.BRIEF DESCRIPTION

[0007] The present disclosure provides a single-phase heat transfer composition comprising at least one compound of formula I:CF3(CF2)nCZ=CZ(CF2)nCF3 (I) in a form of any one of its isomers or a mixture thereof, wherein: n is an integer in a range of from 1 to 5, when n is 1 or 2, Z is CX3, each X is independently selected from F or Cl, and when n is 3, 4, or 5, Z is H.

[0008] The present disclosure also provides a compound, wherein the compound is 4,5-bis-trifluoromethyl-1 , 1 ,1 ,2,2,3,3,6,6,7,7,8,8,8-tetradecafluoro-4-octene.

[0009] The present disclosure also provides an immersion cooling unit including an immersion cell defining an internal cavity. An electronic or electrical component ispositioned in the internal cavity. A dielectric working fluid partially fills the internal cavity and at least partially immerses the energy storage device, IT equipment, computer server, etc. The dielectric working fluid includes a single-phase heat transfer composition comprising at least one compound of formula I:CX3(CX2)nCZ=CZ(CX2)nCX3 (I) in a form of any one of its isomers or a mixture thereof, wherein: n is an integer in a range of from 1 to 5, when n is 1 or 2, Z is CXs, each X is independently selected from F or Cl, and when n is 3, 4, or 5, Z is H.

[0010] The present disclosure also provides a method for cooling electrically charged equipment, such as but not limited to energy storage devices (such as batteries), IT equipment, computer servers including those used in data centers and crypto currency mining applications. The method includes at least partially immersing an electrical component in a working fluid; and transferring heat from the electrical component using the working fluid; wherein the working fluid comprises a single-phase heat transfer composition comprising at least one compound of formula I:CX3(CX2)nCZ=CZ(CX2)nCX3(I) in a form of any one of its isomers or a mixture thereof, wherein: n is an integer in a range of from 1 to 5, when n is 1 or 2, Z is CXs, each X is independently selected from F or Cl, and when n is 3, 4, or 5, Z is H.

[0011] The present disclosure also provides a method for replacing a dielectric fluid in an immersion cooling system. The method includes charging an immersioncooling system that was designed for use with a working fluid with a single-phase heat transfer composition comprising at least one compound of formula I:CX3(CX2)nCZ=CZ(CX2)nCX3(I) in a form of any one of its isomers or a mixture thereof, wherein: n is an integer in a range of from 1 to 5, when n is 1 or 2, Z is CXs, each X is independently selected from F or Cl, and when n is 3, 4, or 5, Z is H.

[0012] The present disclosure also provides an immersion heating unit including an immersion cell defining an internal cavity. An electronic or electrical component is positioned in the internal cavity. A dielectric working fluid partially fills the internal cavity and at least partially immerses the energy storage device, IT equipment, computer server, etc. The dielectric working fluid includes a single-phase heat transfer composition comprising at least one compound of formula I:CX3(CX2)nCZ=CZ(CX2)nCX3(I) in a form of any one of its isomers or a mixture thereof, wherein: n is an integer in a range of from 1 to 5, when n is 1 or 2, Z is CXs, each X is independently selected from F or Cl, and when n is 3, 4, or 5, Z is H.

[0013] The present disclosure also provides a method for heating electrically charged equipment, such as but not limited to energy storage devices (such as batteries), IT equipment, computer servers including those used in data centers and crypto currency mining applications. The method includes at least partially immersing an electrical component in a working fluid; and transferring heat to the electrical component using the working fluid; wherein the working fluid comprises asingle-phase heat transfer composition comprising at least one compound of formula I:CX3(CX2)nCZ=CZ(CX2)nCX3 (I) in a form of any one of its isomers or a mixture thereof, wherein: n is an integer in a range of from 1 to 5, when n is 1 or 2, Z is CXs, each X is independently selected from F or Cl, and when n is 3, 4, or 5, Z is H.

[0014] The present disclosure also provides a method for replacing a dielectric fluid in an immersion heating system. The method includes charging an immersion heating system that was designed for use with a working fluid with a single-phase heat transfer composition comprising at least one compound of formula I: CX3(CX2)nCZ=CZ(CX2)nCX3 (I) in a form of any one of its isomers or a mixture thereof, wherein: n is an integer in a range of from 1 to 5, when n is 1 or 2, Z is CXs, each X is independently selected from F or Cl, and when n is 3, 4, or 5, Z is H.

[0015] The present disclosure also provides an immersion heating unit including an immersion cell defining an internal cavity. An electronic or electrical component is positioned in the internal cavity. A dielectric working fluid partially fills the internal cavity and at least partially immerses the energy storage device, IT equipment, computer server, etc. The dielectric working fluid includes a single-phase heat transfer composition comprising at least one compound of formula I:CF3(CF2)nCX=CX(CF2)nCF3 (I) in a form of any one of its isomers or a mixture thereof,wherein: n is an integer in a range of from 1 to 5, when n is 1 or 2, X is CF3, and when n is 3, 4, or 5, X is H.

[0016] The present disclosure also provides a method for heating electrically charged equipment, such as but not limited to energy storage devices (such as batteries), IT equipment, computer servers including those used in data centers and crypto currency mining applications. The method includes at least partially immersing an electrical component in a working fluid; and transferring heat to the electrical component using the working fluid; wherein the working fluid comprises a single-phase heat transfer composition comprising at least one compound of formula I:CF3(CF2)nCX=CX(CF2)nCF3 (I) in a form of any one of its isomers or a mixture thereof, wherein: n is an integer in a range of from 1 to 5, when n is 1 or 2, X is CF3, and when n is 3, 4, or 5, X is H.

[0017] The present disclosure also provides a method for replacing a dielectric fluid in an immersion heating system. The method includes charging an immersion heating system that was designed for use with a working fluid with a single-phase heat transfer composition comprising at least one compound of formula I: CF3(CF2)nCX=CX(CF2)nCF3 (I) in a form of any one of its isomers or a mixture thereof, wherein: n is an integer in a range of from 1 to 5,when n is 1 or 2, X is CF3, and when n is 3, 4, or 5, X is H.BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Embodiments are illustrated in the accompanying figures to improve understanding of concepts as presented herein.

[0019] Figure 1 is a perspective view of an immersion unit in accordance with the present disclosure.DETAILED DESCRIPTION

[0020] As used herein, the terms “comprises,” “comprising,” “includes,” “including,” “has,” “having” or any other variation thereof, are intended to cover a non-exclusive inclusion. For example, a process, method, article, or apparatus that comprises a list of elements is not necessarily limited to only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Further, unless expressly stated to the contrary, “or” refers to an inclusive or and not to an exclusive or. For example, a condition A or B is satisfied by any one of the following: A is true (or present) and B is false (or not present), A is false (or not present) and B is true (or present), and both A and B are true (or present).

[0021] Also, use of “a” or “an” are employed to describe elements and components described herein. This is done merely for convenience and to give a general sense of the scope of the invention. This description should be read to include one or at least one and the singular also includes the plural unless it is obvious that it is meant otherwise.

[0022] As used herein, the term “isomer” refers to molecules with identical molecular formulas but distinct arrangements of atoms in space. Isomers include structural isomers and stereoisomers. Stereoisomers include (R)- and (S)- enantiomers, cis / trans diastereomers, and (E)- and (Z)- isomers. Each compound disclosed in the present disclosure, regardless of whether a particular isomer is depicted, discloses all of the individual isomers as well as every mixture of isomers.

[0023] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of embodiments of the present disclosure, suitable methods and materials are described below. All publications, patent applications, patents, and other references mentioned herein are incorporated by reference in their entirety, unless a particular passage is cited. In case of conflict, the present specification, including definitions, will control. In addition, the materials, methods, and examples are illustrative only and not intended to be limiting.

[0024] Many aspects and embodiments have been described herein and are merely exemplary and not limiting. After reading this specification, skilled artisans appreciate that other aspects and embodiments are possible without departing from the scope of the invention.

[0025] Described herein are single-phase heat transfer compositions comprising at least one compound of formula I:CX3(CX2)nCZ=CZ(CX2)nCX3 (I) in a form of any one of its isomers or a mixture thereof, wherein: n is an integer in a range of from 1 to 5, when n is 1 or 2, Z is CXs, each X is independently selected from F or Cl, and when n is 3, 4, or 5, Z is H.

[0026] Also described herein are novel methods of using the single-phase heat transfer compositions.

[0027] The single-phase heat transfer compositions address the outstanding need for an ultra-low GWP, non-flammable, single-phase immersion fluid having low viscosity, excellent dielectric and heat transfer properties, good oxidation resistance, and good fluid stability and chemical compatibility with typical materials of construction.

[0028] Exemplary desirable properties are shown in the table below. HFE-7500 is 3-ethoxy-1 ,1 ,1 ,2,3,4,4,5,5,6,6,6-dodecafluoro-2-trifluoromethyl-hexane and FC-7283, FC-40, and FC-43 each refer to perfluoro compounds, C5-18 (CAS 86508-42-1).We are unaware of any commercially available single-phase heat transfer compositions possess all these properties.

[0029] In the above table, forced convection heat transfer Figure of Merit (FOM) is defined as:where: k = liquid thermal conductivity at 40°C p = liquid density at 40°CCP= liquid specific at constant pressure 40°C.

[0030] Generally, the single-phase heat transfer composition is useful for heating applications and / or cooling applications. Particular embodiments are described herein with respect to cooling for the sake of brevity, but are also applicable to heating or cooling and heating In some embodiments, the single-phase heat transfer composition is useful for a cooling application. In some embodiments, the singlephase heat transfer composition is useful for a heating application. In someembodiments, the single-phase heat transfer composition is useful for integrated heating and cooling applications.

[0031] In some embodiments, it is particularly beneficial to for a single-phase heat transfer composition to have low viscosity in order to reduce pump power and increase efficiency of single-phase immersion cooling systems. Even with a relatively lower heat transfer performance, a low viscosity liquid enables a pump to potentially provide a higher flow rate without a significant penalty in frictional pressure drop. This results in a higher pump power when compared with a higher viscosity fluid. A higher flow rate yields higher fluid velocities and consequently yields improved convective heat transfer removal from hot components.

[0032] In one embodiment, the at least one compound of formula I is present in the form of an (E)-isomer.

[0033] In one embodiment, the at least one compound of formula I is present in the form of a (Z)-isomer.

[0034] In one embodiment, the at least one compound of formula I is present in the form of a mixture of an (E)-isomer and a (Z)-isomer.

[0035] In one embodiment, the compositions comprise 1 ,1 ,1 ,2,2,3,3,4,4,7,7,8,8,9,9,10,10,10-octadecafluoro-5-decene.

[0036] In one embodiment, the compositions comprise 1 ,1 ,1 ,2,2,3,3,4,4,5,5,8,8,9,9,10,10,11 ,11 ,12,12,12-docosafluoro-6-dodecene.

[0037] In one embodiment, the compositions comprise1 ,1 ,1 ,2,2,3,3,4,4,5,5,6,6,9,9,10,10,11 ,11 ,12,12,13,13,14,14,14-hexacosafluoro-7- tetradecene.

[0038] In one embodiment, the compositions comprise 3,4-bis-trifluoromethyl- 1 , 1 ,1 ,2,2,5,5,6,6,6-decafluoro-3-hexene.

[0039] In one embodiment, the compositions comprise 4,5-bis-trifluoromethyl- 1 , 1 ,1 ,2,2,3,3,6,6,7,7,8,8,8-tetradecafluoro-4-octene.

[0040] In one embodiment, the compositions consist essentially of 1 ,1 ,1 ,2,2,3,3,4,4,7,7,8,8,9,9,10,10,10-octadecafluoro-5-decene.

[0041] In one embodiment, the compositions consist essentially of 1 ,1 ,1 ,2,2,3,3,4,4,5,5,8,8,9,9,10,10,11 ,11 ,12,12,12-docosafluoro-6-dodecene.

[0042] In one embodiment, the compositions consist essentially of1 ,1 ,1 ,2,2,3,3,4,4,5,5,6,6,9,9,10,10,11 ,11 ,12,12,13,13,14,14,14-hexacosafluoro-7- tetradecene.

[0043] In one embodiment, the compositions consist essentially of 3,4-bis- trifluoromethyl-1 ,1,1 ,2,2,5,5,6,6,6-decafluoro-3-hexene.

[0044] In one embodiment, the compositions consist essentially of 4,5-bis- trifluoromethyl-1 ,1,1 ,2,2,3,3,6,6,7,7,8,8,8-tetradecafluoro-4-octene.

[0045] In one embodiment, the compositions consist of 1 ,1 ,1 ,2,2,3,3,4,4,7,7,8,8,9,9,10,10,10-octadecafluoro-5-decene.

[0046] In one embodiment, the compositions consist of 1 ,1 ,1 ,2,2,3,3,4,4,5,5,8,8,9,9,10,10,11 ,11 ,12,12,12-docosafluoro-6-dodecene.

[0047] In one embodiment, the compositions consist of1 ,1 ,1 ,2,2,3,3,4,4,5,5,6,6,9,9,10,10,11 ,11 ,12,12,13,13,14,14,14-hexacosafluoro-7- tetradecene.

[0048] In one embodiment, the compositions consist of 3,4-bis-trifluoromethyl- 1 , 1 ,1 ,2,2,5,5,6,6,6-decafluoro-3-hexene.

[0049] In one embodiment, the compositions consist of 4,5-bis-trifluoromethyl- 1 , 1 ,1 ,2,2,3,3,6,6,7,7,8,8,8-tetradecafluoro-4-octene.

[0050] In some embodiments, the compositions of the present application further comprise stabilizers that reduce degradation over time and elevated temperatures. In these embodiments, the compositions are stable.

[0051] The present application provides compositions, comprising single-phase heat transfer compositions and an additional component selected from the group consisting of one or more antioxidants and one or more acid scavengers, or any mixture thereof. In these embodiments, the compositions are resistant to oxidation.

[0052] In some embodiments, the one or more acid antioxidants are selected from butylated hydroxy toluene (BHT), hydroquinone monomethyl ether (HQ MME), 2-tert-butyl-6-methylphenol, 2-tert-butyl-5-methylphenol and 2-tert-butyl-4-ethylphenol. In some embodiments, the one or more scavengers are selected from 1 ,3-dioxolane, 1 ,2-epoxybutane and nitromethane.

[0053] Large scale computer server systems can perform significant workloads and generate a large amount of heat during their operation. A significant portion of the heat is generated from their operation. Due in part to the amount of heat generated, these systems are typically mounted in stacked configurations with large internal cooling fans and heat dissipating fins. As the size and density of these systems increases the thermal challenges are even greater, and eventually outpace the ability for forced air systems.

[0054] Two-phase immersion cooling is an emerging cooling technology for the high performance cooling market as applied to high performance high power density server systems, IT equipment used in Data centers, crypto currency mining facilities. It relies on the heat absorbed in the process of vaporizing an immersion liquid into a gas. The fluids used in this application must meet certain requirements to be viable in use. For example, the boiling temperature of the fluid should be in the range between 30-75°C. Generally, this range accommodates maintaining the server components at a sufficiently cool temperature while allowing generated heat to be dissipated sufficiently to an external heat sink. Alternatively, the saturation temperature of the fluid, or its boiling temperature, can be varied by varying the pressure inside the tank. The temperature of the server components would then vary as a result of the change in saturation temperature of the fluid.

[0055] Single phase immersion cooling has a long history in computer server cooling. Because the temperature of the hot components is lower than the boiling point of the fluid, there is no phase change in single phase immersion cooling. Instead, the liquid warms as it circulates through the computer server or heat generating device, and then is circulated with a pump to a heat exchanger for cooling prior to returning to the server or heat generating device, thus transferring heat away from those components. Alternatively, the fluids can circulate without a pump by natural convection; however, heat transfer performance is inferior to systems with forced flow by a pump. Fluids used for single phase immersion cooling have the same requirements as those for two-phase immersion cooling, except that the boilingtemperatures are typically higher than 30-75°C, to reduce loss by evaporation and avoid the boiling of the fluid.

[0056] Provided is an immersion cooler using improved single-phase heat transfer compositions. Some embodiments of the present disclosure, for example, in comparison to concepts failing to include one or more of the features disclosed herein, provide an immersion cooler having fluids for thermal management which possess a combination of desirable properties, including ultra-low GWP, nonflammability, non-combustibility, no flash-point, low viscosity, excellent dielectric heat transfer properties (e.g., in the form of a Figure of Merit) equivalent to or better than other fluorochemicals used in same applications, and good fluid stability and chemical compatibility with typical materials of construction.

[0057] Also provided is a method of immersion cooling wherein the device is a heat generating component, comprising at least partially immersing the heat generating component into the immersion cooling fluid in a liquid state, and transferring heat from the heat generating component using the immersion cooling fluid. Such devices include high capacity energy storage devices, electrical components, IT equipment, computer servers, mechanical components and optical components. Examples of devices of the present disclosure include, but are not limited to, microprocessors, wafers used to manufacture semiconductor devices, power control semiconductors, electrical distribution switch gear, power transformers, circuit boards, multi-chip modules, packaged and unpackaged semiconductor devices, laser, fuel cells, electrochemical cells and energy storage devices such as batteries. In some embodiments, the device is an electronic component selected from: high-capacity energy storage devices, computer servers, datacenter servers, GPUs, CPUs, solar photovoltaics, batteries, insulated-gate bipolar transistor (IGBT) devices, telecommunication infrastructure, military electronics, televisions, cell phones, monitors, drones, automotive batteries, powertrains for electric vehicles, power electronics, avionics devices, power devices, power transformers, displays, microprocessors, wafers used to manufacture semiconductor devices, power control semiconductors, electrical distribution switch gear, circuit boards, multi-chip modules, packaged and unpackaged semiconductor devices, lasers, fuel cells, electrochemical cells, and combinations thereof. In some embodiments the device can include a chiller, a heater, or a combination thereof.

[0058] In certain embodiments, the devices can include electronic devices, such as processors, including microprocessors. Microprocessors typically have maximum operating temperatures of about 85°C, so effective heat transfer is required in conditions of high processing power, i.e. high heat rejection rates. In extreme or mal-functioning conditions, operating temperatures can reach values near about 100°C. In other embodiments, the devices may include energy storage systems, such as batteries. When rapidly charged or discharged, batteries can reject a significant amount of heat that needs to be effectively removed to avoid overheating, internal damage, thermal runaway to adjacent batteries and potentially fire. As these electronic and electric devices become denser, and more powerful, the amount heat generated per unit of time and volume increases. Therefore, the mechanism of heat transfer plays an important role in processor performance. The heat transfer fluid typically has good heat transfer performance, good electrical compatibility (even if used in “indirect contact” applications such as those employing cold plates), as well as low toxicity, low or nonflammability and low environmental impact. Good electrical compatibility suggests that the heat-transfer fluid candidate exhibit high dielectric strength or high breakdown voltage, high volume resistivity, low dissipation factor or loss tangent, low dielectric constant and poor solvency for polar materials. Additionally, the heat-transfer fluid should exhibit good material compatibility, that is, it should not affect typical materials of construction in an adverse manner.

[0059] In some embodiments, such as electric vehicle applications, the singlephase heat transfer compositions are useful as a heat transfer fluid for thermal management (i.e., cooling and / or heating). The compositions may be used with components such as, but not limited to, batteries (e.g., by immersion cooling or coldplate), power electronics, inverters, e-motors, e-powertrains, electric charging cables, computer chips, and combinations thereof. These components may be cooled in a singular loop.

[0060] There continues to be a need for working fluids for immersion cooling that satisfy the dielectric applications of the industry while having a GWP below current requirements for the industry, which are typically less than 150. In another embodiment, the GWP of a working fluid is less than 100. In another embodiment, the compositions disclosed have a Global Warming Potential (GWP) of not greater than 50. As used herein, “GWP” is measured relative to that of carbon dioxide andover a 100-year time horizon, as defined in “The Scientific Assessment of Ozone Depletion, 2002, a report of the World Meteorological Association’s Global Ozone Research and Monitoring Project.”

[0061] It is highly desirable that the new fluids have equivalent or superior heat transfer properties compared to existing fluorochemical fluids, as well as similar or lower viscosity to existing fluids, so that they can replace these fluids in existing systems without significant loss in thermal performance or mechanical modifications; and in new systems designed for existing fluids without significant mechanical design changes. The practice of replacing an existing fluid with a new fluid in an existing system is often called “retrofit”. It is also important that the proposed fluids have similar material compatibility characteristics to the existing fluids.

[0062] It is also highly desirable that the new fluids provide at least minimum dielectric properties required by the application, or even superior dielectric properties compared to existing fluids so that they can replace these fluids in existing systems without significant electrical or mechanical modifications; and in new systems designed for existing fluids without significant electrical or mechanical design changes. The desirable dielectric properties include high volume resistivity, low dielectric constant, high dielectric strength and low loss tangent.

[0063] In one embodiment the normal boiling point of the new dielectric fluid may be within at least 30°C of the fluid being replaced. In another embodiment the normal boiling point of the new dielectric fluid may be within at least 15°C of the fluid being replaced. In another embodiment the normal boiling point of the new dielectric fluid may be within 10°C. In yet another embodiment, the normal boiling point of the new dielectric fluid may be within 5°C.

[0064] The dielectric working fluids may also be selected to exhibit a dielectric constant, volume resistivity, dielectric strength and loss tangent (dissipation factor) suitable for direct contact with electrical components. In general, materials exhibiting a low dielectric constant, low loss tangent or dissipation factor, high volume resistivity and large dielectric strength provide increased electrical insulation of the energy storage device, or electrically charged components immersed therein as well as reduced signal loss. In some embodiments, the dielectric constant of the dielectric working fluids is less than about 8 over the operational frequency range(which can go as high as 100 GHz). In some embodiments, suitable dielectric working fluids include compounds and mixtures having a dielectric constant over the operational frequency range (up to about 100 GHz) of less than 7.3, or less than 5.5, or less than 5.0, or less than 4.0, or less than 3.5, or less than 2.7. Other embodiments include compounds and mixtures having a dielectric constant greater than 1.0 and less than 8.0 or greater than 2.0 and less than 7.3 or greater than 2.5 and less than 5.5 or greater than 3.5 and less than 5.0.

[0065] Another characteristic of a good working fluid is that it possesses a high volume resistivity. Volume resistivity is an intrinsic property which measures how strongly a system or material resists electric current per unit length of a unit cross section, typically expressed in units of ohm-cm or ohm-m. A higher volume resistivity means the system or material is a better electrical insulator. The electrical resistance of a system or material can be calculated by multiplying volume resistivity by the length and dividing by the cross-sectional area of the system or material.

[0066] So, a higher volume resistivity dielectric fluid is desirable as it leads to a higher electrical resistance and, consequently, a lower current leakage. Current leakage, for instance, can lead to self-discharge of energy storage devices such as batteries. It also means electrical components with different voltage can be placed closer (smaller “L”) for a given minimum resistance requirement, potentially leading to more compact assemblies. In one embodiment effective working fluids have a volume resistivity, measured at 25 °C of at least 1 x 1010ohm-cm. In another embodiment, an effective working fluid has a volume resistivity of at least 1 x 1011ohm-cm. In another embodiment, an effective working fluid has a volume resistivity of at least 1 x 1012ohm-cm. In another embodiment, an effective working fluid has a volume resistivity of at least 1 x 1013ohm-cm. In another embodiment, an effective working fluid has a volume resistivity of at least 1 x 1014ohm-cm. Water is known for having much lower volume resistivity. Thus, fluids with high volume resistivity are also desirable as, in case of the presence of water in the fluid, they would still maintain adequate levels of actual volume resistivity.

[0067] Another important dielectric fluid property is the dielectric strength which is defined as the maximum electric field or voltage, per unit of length, a material can resist without undergoing electrical breakdown or arching and becoming electricallyconductive. It is typically measured in units of kV / mm or kV / 0.1” gap. For a given distance or “gap”, the voltage at which a material becomes electrically conductive is called the breakdown voltage. A higher dielectric strength material is advantageous since it allows a higher voltage between two conductors or it allows two conductors to be placed closer, leading to potentially more compact assemblies. In one embodiment, the dielectric strength is greater than about 10 kV / 0.1” gap. In another embodiment, the dielectric strength is greater than about 20 kV / 0.1” gap. In yet another embodiment, the dielectric strength is greater than about 30 kV / 0.1” gap. In yet another embodiment, the dielectric strength is greater than about 35 kV / 0.1” gap. In yet another embodiment, the dielectric strength is greater than about 40 kV / 0.1” gap.

[0068] Dielectric loss tangent, sometimes called a dissipation factor, is another critical dielectric property particularly in high frequencies due to its impact on signal attenuation or signal loss. It is defined with the tan(<5), which is the ratio or vector of the imaginary component to the relative real component of the permittivity. It is also a measure of the rate at which energy carried by the electromagnetic field (RF) traveling through a dielectric is absorbed by that dielectric, i.e. it quantifies the dissipation of electromagnetic energy in a form of heat. Furthermore, the loss tangent is highly dependent on frequency and can increase particularly above frequencies of 1 GHz which can be found in applications such as data center, 5G and Wi-fi technology. More importantly, the signal loss or attenuation per unit length, typically measured in terms of dB / cm is proportional to the loss tangent. In other words, for a signal travelling through a dielectric fluid, the higher the loss tangent of the fluid, the higher the signal loss per unit length and consequently the shorter the distance it can travel. Thus, in some embodiments, it is very desirable that dielectric fluids have low loss tangent values in frequencies above 1GHz to up to about 100 GHz. The fluids discovered by the inventors have shown very favorable values of loss tangent at high frequencies.

[0069] Other desirable characteristic of an immersion cooling fluid relates its ability of not significantly damaging, or not significantly reacting with, IT and computer parts such as cables, wires, seals, metals, among other parts, as well as constructions materials of the tank which are exposed to the dielectric fluid.

[0070] It is also desirable that these fluids have similar interactions with electronic components compared to the existing fluids so to minimize the replacement of parts.

[0071] Contaminant control measures, such as filter systems, may be used to remove solid, liquid, or vapor residues that may be generated as a result of reactivity with materials of construction. Contamination control measures can also be used to maintain low enough acid and water levels.

[0072] It is also desirable that these fluids are non-flammable or present no flash point. Standards such as ASTM D56, D92, D93, D1310, and E681 can be used to assess flammability.

[0073] Better heat transfer coefficients yield better heat removal which, for instance, can allow batteries immersed in a dielectric liquid to be charged at a faster rate without leading to potential thermal runaway. Heat transfer coefficients can be experimentally measured or calculated using experimentally determined heat transfer correlations combined with experimentally determined thermophysical properties. Heat transfer performance can also be assessed by Figures of Merit.

[0074] The power usage or efficiency of data centers can be quantified in terms of PUE - Power Utilization Effectiveness. The lower the PUE or the closer to 1.0, the lower the energy utilized to remove a given amount of heat from data centers. It is highly desirable that immersion tanks with dielectric fluids lead to operate at PUE values close to 1.0. The PUE of an immersion cooling tank can be obtained by measuring the overall energy dissipated by the immersed electronic equipment and the energy consumed by the tank. Due to equivalent dielectric, thermodynamic and heat transfer properties, the fluids proposed can also be used to replace existing fluids in existing equipment in a practice often called “retrofit”. The retrofit could be partial when only a percentage of the existing fluid is replaced or full, when the entire fluid is replaced with a new fluid.

[0075] An embodiment of an immersion cooling unit 100 is shown in Figure 1. The immersion cooling system 100 includes an immersion cell 110 defining an internal cavity 120. An energy storage device 130, to be cooled, may be placed in the internal cavity 120. A dielectric working fluid 140 partially fills the internal cavity 120. The dielectric working fluid 140 at least partially immerses the energy storage device 130. In some embodiments, the dielectric working fluid 140 substantially immersesthe energy storage device 130. In one embodiment, the dielectric working fluid 140 completely immerses the energy storage device 130. A cooling unit 150 (i.e., a heat transfer device) is positioned externally to the immersion cell 110. The cooling unit 150 is fluidly connected to the immersion cell 110. The cooling unit 150 is configured to fluidly receive at least a portion of the dielectric working fluid 140 from the immersion cell 110. The cooling unit 150 is further configured to extract heat from the dielectric working fluid 140, thereby reducing the temperature of the dielectric working fluid 140. In one embodiment, the cooling unit 150 includes a heat exchanger. In one embodiment, the heat transferred to the cooling unit 150 is released into the environment. The cooling unit 150 is further configured to return the cooled dielectric working fluid 240 to the immersion cooling cell 110. In some embodiments, a motive force may be provided to the dielectric working fluid 140. In one embodiment, the motive force may be provided by one or more circulation pumps 160. In one embodiment, the motive force may be provided by convective flow.

[0076] The dielectric working fluids of the immersion cooler 100 are selected to be in the liquid state over the operational temperature range of the immersion cooler 100. In some embodiments, the operational temperature is at least 25°C, at least 30°C, at least 40°C, at least 50°C, at least 60°C, at least 65°C, at least 70°C, less than 100°C, less than 90°C, less than 80°C, less than 70°C, less than 65°C, less than 60°C, and combinations thereof.

[0077] Due to equivalent or better dielectric, thermodynamic and heat transfer properties, the fluids proposed can also be used to replace existing fluids in existing equipment in a practice often called “retrofit”.

[0078] Liquid water or moisture can be introduced into the fluid when the tank is open and the liquid is exposed to outside moist air. Moisture can also come from a server or other components, or materials of construction that absorb moisture when exposed to moist air and release that moisture into the fluid when the server is submerged. The presence of water in the cooling system (particularly in the headspace) is undesirable. It may contribute to corrosion of metal components in the headspace of the system. It may contribute to corrosion of metal components in the headspace of the system. The presence of water in the dielectric fluid can bedetrimental to its dielectric properties since water has significantly lower resistivity (5x105ohm-cm for distilled water).

[0079] Semiconductor surfaces or magnetic media disks of silica, glass, metal or metal oxide, or carbon may have contaminants removed by the compositions of the disclosure. Contaminants may be removed from a disk by contacting the disk with the compositions and recovering the disk from the compositions. In these embodiments, the compositions are cleaning compositions.

[0080] In one embodiment, provided herein are methods of removing contaminants from a product, part, component, substrate, or any other article or portion thereof by contacting the article with a cleaning composition of the present disclosure. As referred to herein, the term “article” refers to all such products, parts, components, substrates, and the like and is further intended to refer to any surface or portion thereof.

[0081] As used herein, the term “contaminant’ is intended to refer to any unwanted material or substance present on the article, even if such substance is placed on the article intentionally. For example, in the manufacture of semiconductor devices it is common to deposit a photoresist material onto a substrate to form a mask for the etching operation and to subsequently remove the photoresist material from the substrate. The term “contaminant,” as used herein, is intended to cover and encompass such a photo resist material. Hydrocarbon based oils and greases and dioctylphthalate (i.e., bis(2-ethylhexyl) phthalate) are examples of the contaminants that may be found on the carbon coated disks or in data center applications.

[0082] In another embodiment, for applications in which the article includes contaminants that are difficult to remove, the method of the disclosure involves raising the temperature of the cleaning composition above ambient temperature or to any other temperature that is effective in such application to substantially improve the cleaning action of the cleaning composition. In one such embodiment, such processes are also generally used for large volume assembly line operations where the cleaning of the article, particularly metal parts and assemblies, must be done efficiently and quickly.

[0083] In one embodiment, the cleaning methods of the present disclosure comprise immersing the article to be cleaned in liquid cleaning composition at anelevated temperature. In another embodiment, the cleaning methods of the present disclosure comprise immersing the article to be cleaned in liquid cleaning composition at about the boiling point of the cleaning composition. In one such embodiment, this step removes a substantial amount of the target contaminant from the article. In yet another embodiment, this step removes a major portion of the target contaminant from the article. In one embodiment, this step is then followed by immersing the article in freshly distilled cleaning composition, which is at a temperature below the temperature of the liquid cleaning composition in the preceding immersion step. In one such embodiment, the freshly distilled cleaning composition is at about ambient or room temperature. In certain preferred embodiments, the article may be sprayed with distilled cleaning composition before final rinsing.

[0084] In one embodiment, the compositions of the present disclosure are stable in the presence of moisture, air, and other contaminants (e.g., plasticizer). In these embodiments, the compositions do not hydrolyze or react with plasticizer.

[0085] The present cleaning methods may also comprise cold cleaning in which the contaminated article is either immersed in the fluid cleaning composition of the present disclosure under ambient or room temperature conditions or wiped under such conditions with rags or similar objects soaked in the cleaning composition.

[0086] In one embodiment, the compositions of the present disclosure may further contain a co-solvent. Such co-solvents are desirable where the present compositions are employed in cleaning conventional process residue from substrates, e.g., removing soldering fluxes and degreasing mechanical components comprising substrates of the present invention. Such co-solvents include alcohols (such as methanol, ethanol, isopropanol), ethers (such as diethyl ether, methyl tertiary-butyl ether), ketones (such as acetone), esters (such as ethyl acetate, methyl dodecanoate, isopropyl myristate and the dimethyl or diisobutyl esters of succinic, glutaric or adipic acids or mixtures thereof), ether alcohols (such as propylene glycol monopropyl ether, dipropylene glycol monobutyl ether, and tripropylene glycol monomethyl ether), and hydrocarbons (such as pentane, cyclopentane, hexane, cyclohexane, heptane, octane), and hydrochlorocarbons (such as trans-1,2- dichloroethylene). When such a co-solvent is employed with the presentcomposition for substrate cleaning, it may be present in an amount of from about 1 weight percent to about 50 weight percent based on the weight of the overall composition.

[0087] While the invention has been described with reference to one or more embodiments, it will be understood by those skilled in the art that various changes may be made, and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiments disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims. In addition, all numerical values identified in the detailed description shall be interpreted as though the precise and approximate values are both expressly identified.EXAMPLES

[0088] The concepts described herein will be further described in the following examples, which do not limit the scope of the invention described in the claims. Note that not all of the activities described above in the general description or the examples are required, that a portion of a specific activity may not be required, and that one or more further activities may be performed in addition to those described. Still further, the order in which activities are listed are not necessarily the order in which they are performed.

[0089] In the foregoing specification, the concepts have been described with reference to specific embodiments. However, one of ordinary skill in the art appreciates that various modifications and changes can be made without departing from the scope of the invention as set forth in the claims below. Accordingly, the specification is to be regarded in an illustrative, rather than a restrictive sense, and all such modifications are intended to be included within the scope of invention.

[0090] Benefits, other advantages, and solutions to problems have been described above with regard to specific embodiments. However, the benefits, advantages, solutions to problems, and any feature(s) that may cause any benefit, advantage, orsolution to occur or become more pronounced are not to be construed as a critical, required, or essential feature of any or all the claims.

[0091] It is to be appreciated that certain features are, for clarity, described herein in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features that are, for brevity, described in the context of a single embodiment, may also be provided separately or in any subcombination. Further, reference to values stated in ranges include each and every value within that range.Example 1. Property Characterization.

[0092] It was experimentally determined that single-phase heat transfer compositions could be produced with the inclusion of one or more of the compounds of Table 1 .TABLE 1. COMPOUNDS FOR SINGLE-PHASE HEAT TRANSFER COMPOSITIONS.

[0093] The properties of the compounds for the single-phase heat transfer compositions were computationally or experimentally determined as shown in Table 2. Normal boiling point (NBP), viscosity, density, and thermal conductivity were each determined by molecular modeling. Dielectric constant, dissipation factor, and resistivity were experimentally measured. Marking of“<” and “>” indicate approximated values.TABLE 2. PROPERTIES.

[0094] These compounds exhibit excellent properties for use in single-phase heat transfer compositions. Such properties are demonstrated for compound C1 to include very low dielectric constant, very low dissipation factor, high volume resistivity and breakdown voltage, no flash point, low viscosity, and low GWP. Similar properties are expected for compounds C2, C3, C4, and C5.

Claims

WHAT IS CLAIMED IS:

1. A single-phase heat transfer composition comprising at least one compound of formula I:CX3(CX2)nCZ=CZ(CX2)nCX3 (I) in a form of any one of its isomers or a mixture thereof, wherein: n is an integer in a range of from 1 to 5, when n is 1 or 2, Z is CXs, each X is independently selected from F or Cl, and when n is 3, 4, or 5, Z is H.

2. The single-phase heat transfer composition of claim 1 , wherein the at least one compound is 1 ,1,1 ,2, 2, 3, 3, 4, 4, 7, 7, 8, 8, 9, 9, 10, 10, 10-octadecafluoro-5-decene.

3. The single-phase heat transfer composition of claim 1 , wherein the at least one compound is 1 , 1 , 1 ,2, 2, 3, 3, 4, 4, 5, 5, 8, 8, 9, 9, 10, 10,11 , 11 ,12, 12, 12-docosafluoro-6- dodecene.

4. The single-phase heat transfer composition of claim 1 , wherein the at least one compound is 1 , 1 , 1 ,2, 2, 3, 3, 4, 4, 5, 5, 6, 6, 9, 9, 10, 10,11 , 11 ,12, 12, 13,13, 14, 14, 14- hexacosafluoro-7-tetradecene.

5. The single-phase heat transfer composition of claim 1 , wherein the at least one compound is 3,4-bis-trifluoromethyl-1 ,1,1 ,2,2,5,5,6,6,6-decafluoro-3-hexene.

6. The single-phase heat transfer composition of claim 1 , wherein the at least one compound is 4,5-bis-trifluoromethyl-1 ,1,1 ,2,2,3,3,6,6,7,7,8,8,8-tetradecafluoro- 4-octene.

7. A compound, wherein the compound is 4,5-bis-trifluoromethyl- 1 ,1 ,1,2,2,3,3,6,6,7,7,8,8,8-tetradecafluoro-4-octene.

8. An immersion cooling unit comprising: an immersion cell, defining an internal cavity; i) an electronic component in the internal cavity;ii) a dielectric working fluid partially filling the internal cavity; and iii) a heat transfer device; wherein the dielectric working fluid at least partially immerses the electronic component; and wherein the dielectric working fluid includes a single-phase heat transfer composition comprising at least one compound of formula I:CX3(CX2)nCZ=CZ(CX2)nCX3 (I) in a form of any one of its isomers or a mixture thereof, wherein: n is an integer in a range of from 1 to 5, when n is 1 or 2, Z is CXs, each X is independently selected from F or Cl, and when n is 3, 4, or 5, Z is H.

9. The immersion cooling unit of claim 8, wherein the heat transfer device is a remote heat sink, wherein the remote heat sink is configured to receive the working fluid from a pump.

10. The immersion cooling unit of claim 8, wherein an operating temperature range is between 0°C and 80°C.

11. The immersion cooling unit of claim 8, wherein the volume resistivity of the dielectric working fluid is at least 1 x 10 Q-cm.

12. The immersion cooling unit of claim 8, wherein the dielectric working fluid has a global warming potential (GWP) of less than 100.

13. The immersion cooling unit of claim 8, wherein the electronic component comprises at least one component selected from the group consisting of high- capacity energy storage devices, computer servers, datacenter servers, GPUs, CPUs, solar photovoltaics, batteries, insulated-gate bipolar transistor (IGBT) devices, telecommunication infrastructure, military electronics, televisions, cellphones, monitors, drones, automotive batteries, powertrains for electric vehicles, power electronics, avionics devices, power devices, power transformers, displays, microprocessors, wafers used to manufacture semiconductor devices, power control semiconductors, electrical distribution switch gear, circuit boards, multi-chip modules, packaged and unpackaged semiconductor devices, lasers, fuel cells, electrochemical cells, and combinations thereof.

14. The immersion cooling unit of claim 8, wherein the at least one compound is 1 ,1 ,1,2,2,3,3,4,4,7,7,8,8,9,9,10,10,10-octadecafluoro-5-decene.

15. The immersion cooling unit of claim 8, wherein the at least one compound is 1 ,1 ,1,2,2,3,3,4,4,5,5,8,8,9,9,10,10,11,11 ,12,12,12-docosafluoro-6-dodecene.

16. The immersion cooling unit of claim 8, wherein the at least one compound is1 ,1 ,1,2,2,3,3,4,4,5,5,6,6,9,9,10,10,11,11 ,12,12,13,13,14,14,14-hexacosafluoro- 7-tetradecene.

17. The immersion cooling unit of claim 8, wherein the at least one compound is3.4-bis-trifluoromethyl-1 ,1,1 ,2,2,5,5,6,6,6-decafluoro-3-hexene.

18. The immersion cooling unit of claim 8, wherein the at least one compound is4.5-bis-trifluoromethyl-1 ,1,1 ,2,2,3,3,6,6,7,7,8,8,8-tetradecafluoro-4-octene.

19. A method for cooling an electrical component comprising: at least partially immersing an electrical component in a working fluid; and transferring heat from the electrical component using the working fluid; wherein the working fluid comprises a single-phase heat transfer composition comprising at least one compound of formula I:CX3(CX2)nCZ=CZ(CX2)nCX3 (I) in a form of any one of its isomers or a mixture thereof, wherein: n is an integer in a range of from 1 to 5, when n is 1 or 2, Z is CXs,each X is independently selected from F or Cl, and when n is 3, 4, or 5, Z is H.

20. The method of claim 19, wherein said transferring of heat occurs through pumping of said working fluid from the electrical component to be cooled to a remote heat sink.

21. The method of claim 19, wherein the at least one compound is1 ,1 ,1 ,2,2,3,3,4,4,7,7,8,8,9,9,10,10,10-octadecafluoro-5-decene.

22. The method of claim 19, wherein the at least one compound is 1 ,1 ,1 ,2,2,3,3,4,4,5,5,8,8,9,9,10,10,11 ,11 ,12,12,12-docosafluoro-6-dodecene.

23. The method of claim 19, wherein the at least one compound is1 ,1 ,1,2,2,3,3,4,4,5,5,6,6,9,9,10,10,11,11 ,12,12,13,13,14,14,14-hexacosafluoro- 7-tetradecene.

24. The method of claim 19, wherein the at least one compound is 3,4-bis- trifluoromethyl-1 , 1 , 1 ,2,2,5,5,6,6,6-decafluoro-3-hexene.

25. The method of claim 19, wherein the at least one compound is 4,5-bis- trifluoromethyl-1 , 1 , 1 ,2,2,3,3,6,6,7,7,8,8,8-tetradecafluoro-4-octene.

26. A method of replacing a dielectric fluid in an immersion cooling system, comprising: charging an immersion cooling system that was designed for use with a working fluid with a composition comprising a single-phase heat transfer composition comprising at least one compound of formula I:CX3(CX2)nCZ=CZ(CX2)nCX3 (I) in a form of any one of its isomers or a mixture thereof, wherein: n is an integer in a range of from 1 to 5, when n is 1 or 2, Z is CX3,each X is independently selected from F or Cl, and when n is 3, 4, or 5, Z is H.

27. The method of claim 26, wherein the electrical component to fluid thermal resistance of the replacement fluid is lower than or equivalent to said working fluid.

28. The method of claim 26, wherein the electrical component to fluid thermal resistance of the replacement fluid is no higher than 20% greater than that of said working fluid.

29. The method of claim 26, wherein the electrical component to fluid thermal resistance of the replacement fluid is no higher than 10% greater than that of said working fluid.

30. The method of claim 26, wherein the at least one compound is1 ,1 ,1 ,2,2,3,3,4,4,7,7,8,8,9,9,10,10,10-octadecafluoro-5-decene.31 . The method of claim 26, wherein the at least one compound is 1 ,1 ,1 ,2,2,3,3,4,4,5,5,8,8,9,9,10,10,11 ,11 ,12,12,12-docosafluoro-6-dodecene.

32. The method of claim 26, wherein the at least one compound is1 ,1 ,1,2,2,3,3,4,4,5,5,6,6,9,9,10,10,11,11 ,12,12,13,13,14,14,14-hexacosafluoro- 7-tetradecene.

33. The method of claim 26, wherein the at least one compound is 3,4-bis- trifluoromethyl-1 , 1 , 1 ,2,2,5,5,6,6,6-decafluoro-3-hexene.

34. The method of claim 26, wherein the at least one compound is 4,5-bis- trifluoromethyl-1 , 1 , 1 ,2,2,3,3,6,6,7,7,8,8,8-tetradecafluoro-4-octene.

35. An immersion heating unit comprising: an immersion cell, defining an internal cavity; i) an electronic component in the internal cavity; ii) a dielectric working fluid partially filling the internal cavity; and iii) a heat transfer device;wherein the dielectric working fluid at least partially immerses the electronic component; and wherein the dielectric working fluid includes a single-phase heat transfer composition comprising at least one compound of formula I:CF3(CF2)nCX=CX(CF2)nCF3 (I) in a form of any one of its isomers or a mixture thereof, wherein: n is an integer in a range of from 1 to 5, when n is 1 or 2, X is CF3, and when n is 3, 4, or 5, X is H.

36. The immersion heating unit of claim 35, wherein the heat transfer device is a remote heat sink, wherein the remote heat sink is configured to receive the working fluid from a pump.

37. The immersion heating unit of claim 35, wherein an operating temperature range is between 0°C and 80°C.

38. The immersion heating unit of claim 35, wherein the volume resistivity of the dielectric working fluid is at least 1 x 1010 Q-cm.

39. The immersion heating unit of claim 35, wherein the dielectric working fluid has a global warming potential (GWP) of less than 100.

40. The immersion heating unit of claim 35, wherein the electronic component comprises at least one component selected from the group consisting of high- capacity energy storage devices, computer servers, datacenter servers, GPUs, CPUs, solar photovoltaics, batteries, insulated-gate bipolar transistor (IGBT) devices, telecommunication infrastructure, military electronics, televisions, cell phones, monitors, drones, automotive batteries, powertrains for electric vehicles, power electronics, avionics devices, power devices, power transformers, displays, microprocessors, wafers used to manufacture semiconductordevices, power control semiconductors, electrical distribution switch gear, circuit boards, multi-chip modules, packaged and unpackaged semiconductor devices, lasers, fuel cells, electrochemical cells, and combinations thereof.41 . The immersion heating unit of claim 35, wherein the at least one compound is 1 ,1 ,1 ,2,2,3,3,4,4,7,7,8,8,9,9,10,10,10-octadecafluoro-5-decene.

42. The immersion heating unit of claim 35, wherein the at least one compound is 1 ,1 ,1 ,2,2,3,3,4,4,5,5,8,8,9,9,10,10,11 ,11 ,12,12,12-dodecafluoro-6-dodecene.

43. The immersion heating unit of claim 35, wherein the at least one compound is1 ,1 ,1,2,2,3,3,4,4,5,5,6,6,9,9,10,10,11,11 ,12,12,13,13,14,14,14-hexaicosafluoro- 7-tetradecene.

44. The immersion heating unit of claim 35, wherein the at least one compound is3.4-bis-trifluoromethyl-1 ,1 ,1 ,2,2,5,5,6,6,6-decafluoro-3-hexene.

45. The immersion heating unit of claim 35, wherein the at least one compound is4.5-bis-trifluoromethyl-1 ,1 ,1 ,2,2,3,3,6,6,7,7,8,8,8-dodecafluoro-4-octene.

46. A method for heating an electrical component comprising: at least partially immersing an electrical component in a working fluid; and transferring heat to the electrical component using the working fluid; wherein the working fluid comprises a single-phase heat transfer composition comprising at least one compound of formula I:CF3(CF2)nCX=CX(CF2)nCF3 (I) in a form of any one of its isomers or a mixture thereof, wherein: n is an integer in a range of from 1 to 5, when n is 1 or 2, X is CF3, and when n is 3, 4, or 5, X is H.

47. The method of claim 46, wherein said transferring of heat occurs through pumping of said working fluid from a remote heat source to the electrical component to be heated.

48. The method of claim 46, wherein the at least one compound is1 ,1 ,1 ,2,2,3,3,4,4,7,7,8,8,9,9,10,10,10-octadecafluoro-5-decene.

49. The method of claim 46, wherein the at least one compound is 1 ,1 ,1 ,2,2,3,3,4,4,5,5,8,8,9,9,10,10,11 ,11 ,12,12,12-dodecafluoro-6-dodecene.

50. The method of claim 46, wherein the at least one compound is1 ,1 ,1,2,2,3,3,4,4,5,5,6,6,9,9,10,10,11,11 ,12,12,13,13,14,14,14-hexaicosafluoro- 7-tetradecene.51 . The method of claim 46, wherein the at least one compound is 3,4-bis- trifluoromethyl-1 , 1 , 1 ,2,2,5,5,6,6,6-decafluoro-3-hexene.

52. The method of claim 46, wherein the at least one compound is 4,5-bis- trifluoromethyl-1 , 1 , 1 ,2,2,3,3,6,6,7,7,8,8,8-dodecafluoro-4-octene.

53. A method of replacing a dielectric fluid in an immersion heating system, comprising: charging an immersion heating system that was designed for use with a working fluid with a composition comprising a single-phase heat transfer composition comprising at least one compound of formula I:CF3(CF2)nCX=CX(CF2)nCF3 (I) in a form of any one of its isomers or a mixture thereof, wherein: n is an integer in a range of from 1 to 5, when n is 1 or 2, X is CF3, and when n is 3, 4, or 5, X is H.

54. The method of claim 53, wherein the electrical component to fluid thermal resistance of the replacement fluid is lower than or equivalent to said working fluid.

55. The method of claim 53, wherein the electrical component to fluid thermal resistance of the replacement fluid is no higher than 20% greater than that of said working fluid.

56. The method of claim 53, wherein the electrical component to fluid thermal resistance of the replacement fluid is no higher than 10% greater than that of said working fluid.

57. The method of claim 53, wherein the at least one compound is1 ,1 ,1 ,2,2,3,3,4,4,7,7,8,8,9,9,10,10,10-octadecafluoro-5-decene.

58. The method of claim 53, wherein the at least one compound is 1 ,1 ,1 ,2,2,3,3,4,4,5,5,8,8,9,9,10,10,11 ,11 ,12,12,12-dodecafluoro-6-dodecene.

59. The method of claim 53, wherein the at least one compound is1 ,1 ,1,2,2,3,3,4,4,5,5,6,6,9,9,10,10,11,11 ,12,12,13,13,14,14,14-hexaicosafluoro- 7-tetradecene.

60. The method of claim 53, wherein the at least one compound is 3,4-bis- trifluoromethyl-1 , 1 , 1 ,2,2,5,5,6,6,6-decafluoro-3-hexene.61 . The method of claim 53, wherein the at least one compound is 4,5-bis- trifluoromethyl-1 , 1 , 1 ,2,2,3,3,6,6,7,7,8,8,8-dodecafluoro-4-octene.

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