Heat-transfer fluids having reduced flammability

A cooling or heating installation comprising a vapor compression circuit containing a heat transfer fluid, said circuit being totally contained in an enclosure, wherein the relative humidity of air in the enclosure is less than or equal to a value H1 which is less than 45% and the flammability of heat transfer fluid at relative humidity H1 is less than the flammability of the heat transfer fluid at 50% relative humidity wherein said enclosure is distinct from a space containing the fluid or body for which heating or cooling is sought,

• wherein said heat transfer fluid consists of:
• a) 2,3,3,3-tetrafluoropropene
• b) 1,3,3,3-tetrafluoropropene in the E or Z form
• c) mixtures of 2,3,3,3-tetrafluoropropene and 1,3,3,3-tetrafluoropropene in the E or Z form or
• d) at least one heat transfer compound that is a fluoroolefin of formula XCFzR3−z, wherein X is a substituted or unsubstituted, unsaturated C2, C3 or C4 alkyl radical, each R is independently Cl, F, Br, I or H and z is an integer from 1 to 3 and one or more other heat transfer compounds chosen from hydrochlorofluorocarbons, hydrofluorocarbons, fluoroethers, hydrocarbon ethers and ammonia,
• the relative humidity being measured at a temperature of 23° C.

A method of protection against risks of fire or explosion in an enclosure totally containing a vapor compression circuit containing a heat transfer fluid, said method comprising maintaining the relative humidity of air in the enclosure at a value less than or equal to a threshold value H1 which is less than 45%, the flammability of the heat transfer fluid at relative humidity H1 being less than the flammability of the heat transfer fluid at 50% relative humidity wherein said enclosure is distinct from a space containing the fluid or body for which heating or cooling is sought,

• wherein said heat transfer fluid consists of:
• a) 2,3,3,3-tetrafluoropropene
• b) 1,3,3,3-tetrafluoropropene in the E or Z form
• c) mixtures of 2,3,3,3-tetrafluoropropene and 1,3,3,3-tetrafluoropropene in the E or Z form or
• d) at least one heat transfer compound that is a fluoroolefin of formula XCFzR3−z, wherein X is a substituted or unsubstituted, unsaturated C2, C3 or C4 alkyl radical, each R is independently Cl, F, Br, I or H and z is an integer from 1 to 3 and one or more other heat transfer compounds chosen from hydrochlorofluorocarbons, hydrofluorocarbons, fluoroethers, hydrocarbon ethers and ammonia, the relative humidity being measured at a temperature of 23° C.

The method for reducing the GWP of an initial heat transfer fluid comprising at least one first heat transfer compound and a second heat transfer compound, the first heat transfer compound having a GWP greater than the GWP of the second heat transfer compound, said method comprising:

• modification of the composition of the initial heat transfer fluid in order to provide a modified heat transfer fluid, said modification comprising increasing the proportion by mass of the second heat transfer compound and reducing the proportion by mass of the first heat transfer compound in the heat transfer fluid;
• wherein the modified heat transfer fluid exhibits a flammability at a relative humidity H1, H1 being less than 45%, which is less than or equal to the flammability of the initial heat transfer fluid at 50% relative humidity, wherein the modified heat transfer fluid is used at a relative humidity less than or equal to a threshold value H1, which is less than 45% and
• wherein said initial heat transfer fluid consists of:
• a) 2,3,3,3-tetrafluoropropene
• b) 1,3,3,3-tetrafluoropropene in the E or Z form
• c) mixtures of 2,3,3,3-tetrafluoropropene and 1,3,3,3-tetrafluoropropene in the E or Z form or
• d) at least one first heat transfer compound that is a fluoroolefin of formula XCFzR3−z, wherein X is a substituted or unsubstituted, unsaturated C2, C3 or C4 alkyl radical, each R is independently Cl, F, Br, I or H and z is an integer from 1 to 3 and
• one or more other second heat transfer compounds chosen from hydrochlorofluorocarbons, hydrofluorocarbons, fluoroethers, hydrocarbon ethers and ammonia,
• the relative humidity being measured at a temperature of 23° C.

A method for cooling or heating a fluid or a body by means of a vapor compression circuit containing a heat transfer fluid, said circuit being totally contained in an enclosure, and the relative humidity of air in the enclosure being less than or equal to a threshold value H1 which is less than 25%, and the flammability of the heat transfer fluid at relative humidity H1 being less than the flammability of the heat transfer fluid at 50% relative humidity,

• wherein said heat transfer fluid consists of:
• a) 2,3,3,3-tetrafluoropropene
• b) 1,3,3,3-tetrafluoropropene in the E or Z form
• c) mixtures of 2,3,3,3-tetrafluoropropene and 1,3,3,3-tetrafluoropropene in the E or Z form or
• d) at least one heat transfer compound that is a fluoroolefin of formula XCFzR3−z, wherein X is a substituted or unsubstituted, unsaturated C2, C3 or C4 alkyl radical, each R is independently Cl, F, Br, I or H and z is an integer from 1 to 3 and one or more other heat transfer compounds chosen from hydrochlorofluorocarbons, hydrofluorocarbons, fluoroethers, hydrocarbon ethers and ammonia, the relative humidity being measured at a temperature of 23° C.

A cooling or heating installation comprising a vapor compression circuit containing a heat transfer fluid, said circuit being totally contained in an enclosure, wherein the relative humidity of the air in the enclosure is less than or equal to a value H1 which is less than 25% and the flammability of heat transfer fluid at relative humidity H1 is less than the flammability of the heat transfer fluid at 50% relative humidity,

• wherein said heat transfer fluid consists of:
• a) 2,3,3,3-tetrafluoropropene
• b) 1,3,3,3-tetrafluoropropene in the E or Z form
• c) mixtures of 2,3,3,3-tetrafluoropropene and 1,3,3,3-tetrafluoropropene in the E or Z form or
• d) at least one heat transfer compound that is a fluoroolefin of formula XCFzR3−z, wherein X is a substituted or unsubstituted, unsaturated C2, C3 or C4 alkyl radical, each R is independently Cl, F, Br, I or H and z is an integer from 1 to 3 and one or more other heat transfer compounds chosen from hydrochlorofluorocarbons, hydrofluorocarbons, fluoroethers, hydrocarbon ethers and ammonia, the relative humidity being measured at a temperature of 23° C.