TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Composition: The composition comprises an azeotropic or azeotrope-like combination of: Z-1,2-difluoroethylene and 2,3,3,3-tetrafluoropropene; Z-1,2-difluoroethylene and Z-1,2,3,3,3-pentafluoropropene; Z-1,2-difluoroethylene and E-1,2,3,3,3-pentafluoropropene; Z-1,2-difluoroethylene and E-1,3,3,3-tetrafluoropropene; Z-1,2-difluoroethylene and 1,1,1-trifluoropropene; Z-1,2-difluoroethylene and 1,1,2,2-tetrafluoroethane; Z-1,2-difluoroethylene and 1,1,1,2-tetrafluoroethane; Z-1,2-difluoroethylene and 1,1-difluoroethane; Z-1,2-difluoroethylene and fluoroethane; Z-1,2-difluoroethylene and 1,1,1,2,3,3,3-heptafluoropropane; Z-1,2-difluoroethylene and propane; Z-1,2-difluoroethylene and n-butane; Z-1,2-difluoroethylene and isobutane; Z-1,2-difluoroethylene and dimethyl ether; Z-1,2-difluoroethylene and CF3I; Z-1,2-difluoroethylene and CF3SCF3; Z-1,2-difluoroethylene and 1,1,1,2,3,3-hexafluoropropane; Z-1,2-difluoroethylene and 1,1,1,3,3,3-hexafluoropropane; or Z-1,2-difluoroethylene and cyclopropane. The composition comprises: about 1 wt.% to about 69 wt.% Z-1,2-difluoroethylene and about 99 wt.% to about 31 wt.% 2,3,3,3-tetrafluoropropene; about 1 wt.% to about 99 wt.% Z-1,2-difluoroethylene and about 99 wt.% to about 1 wt.% Z-1,2,3,3,3-pentafluoropropene; about 1 wt.% to about 99 wt.% Z-1,2-difluoroethylene and about 99 wt.% to about 1 wt.% E-1,2,3,3,3-pentafluoropropene; about 1 wt.% to about 99 wt.% Z-1,2-difluoroethylene and about 99 wt.% to about 1 wt.% E-1,3,3,3-tetrafluoropropene; about 1 wt.% to about 99 wt.% Z-1,2-difluoroethylene and about 99 wt.% to about 1 wt.% 1,1,1-trifluoropropene; about 1 wt.% to about 99 wt.% Z-1,2-difluoroethylene and about 99 wt.% to about 1 wt.% 1,1,2,2-tetrafluoroethane; about 1 wt.% to about 99 wt.% Z-1,2-difluoroethylene and about 99 wt.% to about 1 wt.% 1,1,1,2-tetrafluoroethane; about 1 wt.% to about 99 wt.% Z-1,2-difluoroethylene and about 99 wt.% to about 1 wt.% 1,1-difluoroethane; about 1 wt.% to about 99 wt.% Z-1,2-difluoroethylene and about 99 wt.% to about 1 wt.% fluoroethane; about 13 wt.% to about 74 wt.% Z-1,2-difluoroethylene and about 87 wt.% to about 26 wt.% 1,1,1,2,3,3,3-heptafluoropropane; about 1 wt.% to about 70 wt.% Z-1,2-difluoroethylene and about 99 wt.% to about 30 wt.% propane; about 1 wt.% to about 99 wt.% Z-1,2-difluoroethylene and about 99 wt.% to about 1 wt.% cyclopropane; about 1 wt.% to about 99 wt.% Z-1,2-difluoroethylene and about 99 wt.% to about 1 wt.% dimethyl ether; about 1 wt.% to about 99 wt.% Z-1,2-difluoroethylene and about 99 wt.% to about 1 wt.% trifluoroiodomethane; or about 16 wt.% to about 65 wt.% Z-1,2-difluoroethylene and about 84 wt.% to about 35 wt.% CF3SCF3. The composition comprises: about 27.8 wt.% Z-1,2-difluoroethylene and about 9.5 wt.% 2,3,3,3-tetrafluoropropene that forms an azeotrope at about 0 degrees C and about 51.0 psia (352 kPa); about 43.7 wt.% Z-1,2-difluoroethylene and about 56.3 wt.% Z-1,2,3,3,3-pentafluoropropene that forms an azeotrope at about 0 degrees C and about 40.1 psia (276 kPa); about 77.0 wt.% Z-1,2-difluoroethylene and about 23.0 wt.% E-1,2,3,3,3-pentafluoropropene that forms an azeotrope at about 0 degrees C and about 35.0 psia (241 kPa); about 50.6 wt.% Z-1,2-difluoroethylene and about 49.4 wt.% E-1,3,3,3-tetrafluoropropene that forms an azeotrope at about 0 degrees C and about 38.1 psia (263 kPa); about 47.5 wt.% Z-1,2-difluoroethylene and about 52.5 wt.% 1,1,1-trifluoropropene that forms an azeotrope at about 0 degrees C and about 39.2 psia (270 kPa); about 41.3 wt.% Z-1,2-difluoroethylene and about 58.7 wt.% 1,1,1,2,3,3,3-heptafluoropropane that forms an azeotrope at about 0 degrees C and about 44.3 psia (305 kPa); about 7 wt.% Z-1,2-difluoroethylene and about 93.0 wt.% propane that forms an azeotrope at about 0 degrees C and about 68.8 psia (474 kPa); about 77.8 wt.% Z-1,2-difluoroethylene and about 22.2 wt.% isobutane that forms an azeotrope at about 0 degrees C and about 37.8 psia (261 kPa); about 31.3 wt.% Z-1,2-difluoroethylene and about 68.7 wt.% CF3I that forms an azeotrope at about 0 degrees C and about 43.5 psia (300 kPa); or about 36.6 wt.% Z-1,2-difluoroethylene and about 63.4 wt.% CF3SCF3 that forms an azeotrope at about 0 degrees C and about 48.6 psia (335 kPa). The composition further comprises at least one lubricant suitable for use in a heat transfer system. The compositions further comprise at least one flammability reducing additive; and at least one stabilizer. The system uses, used or was designed to use R134a. Preferred Method: The process (P1) further involves condensing the vapor phase working fluid thus forming a liquid phase working fluid; and recycling the liquid phase working fluid to be evaporated again. EXAMPLE - No suitable example given.