Disclosed herein are refrigerant and heat transfer fluid compositions
comprising 1,1,1,2,2,4,5,5,5-nonafluoro-4-(trifluoromethyl)-3-pentanone
and at least one hydrocarbon. These compositions are useful in
refrigeration and air conditioning systems that employ a centrifugal
compressor. Also disclosed herein are azeotropic or near azeotropic
refrigerant and heat transfer fluid compositions comprising
1,1,1,2,2,4,5,5,5-nonafluoro-4-(trifluoromethyl)-3-pentanone and at least
one hydrocarbon.