A process for cooling or heating a fluid or a body by a vapor compression circuit having a
centrifugal compressor and containing a
heat transfer fluid, the heat-transfer fluid including at least two of 2,3,3,3-tetrafluoropropene, 1,3,3,3-tetrafluoropropene, 1,1,1,2-tetrafluoroethane, 1,1-difluoroethane and 3,3,3-trifluoropropene, wherein: the ratio of the Mach number of the
centrifugal compressor to the Mach number when the
centrifugal compressor has, under the same operating conditions, the heat-transfer fluid is replaced with 1,1,1,2-tetrafluoroethane is at least 0.97 and at most 1.03; the
compression ratio of the centrifugal compressor is less than or equal to the
compression ratio when the centrifugal compressor has, under the same operating conditions, the heat-transfer fluid is replaced with 1,1,1,2-tetrafluoroethane. Also, equipment suitable for implementing this cooling or heating process, and also to a process for converting existing equipment.