NOVELTY - A composition comprises Z-1,2-difluoroethylene and at least one compound selected from e.g. 2,3,3,3-tetrafluoropropene, Z-1,2,3,3,3-pentafluoropropene, E-1,2,3,3,3-pentafluoropropene, E-1,3,3,3-tetrafluoropropene, 3,3,3-trifluoropropene, difluoromethane, pentafluoroethane, 1,1,2,2-tetrafluoroethane, 1,1,1,2-tetrafluoroethane, 1,1,1-trifluoroethane, 1,1-difluoroethane, fluoroethane, 1,1,1,2,3,3,3-heptafluoropropane, 1,1,1,2,3,3-hexafluoropropane, 1,1,1,3,3,3-hexafluoropropane, 1,1,1,3,3-pentafluoropropane, propane, n-butane, isobutane, propylene, cyclopropane, or n-pentane.    USE - As composition for replacing a refrigerant selected from R134a, R22, R12, R404A, R410A, R407C, R413A, R417A, R422A, R422B, R422C, R422D, R423A, R424A, R426A, R428A, R430A, R434A, R437A, R438A, R507A, and R502, in a system that uses, used or was designed to use the refrigerant; in refrigerant composition; in refrigeration, air-conditioning or heating; in foam blowing agent; in sprayable composition; in process for producing aerosol products; as propellant; for recovering heat; in refrigeration, air conditioning, heat pump or power cycle system apparatus (claimed); and for producing cooling or heat, as heat transfer fluids, foam blowing agents, aerosol propellants, and power cycle working fluids; in processes for producing cooling or heat, as heat transfer fluids, foam blowing agents, aerosol propellants, and fire suppression, fire extinguishing agents and power cycle working fluids.    ADVANTAGE - The composition provides refrigerant compositions and heat transfer fluid compositions that provide unique characteristics to meet the demands of low or zero ozone depletion potential and lower global warming potential as compared to current refrigerants. The composition can be used in all areas of refrigeration and air-conditioning industry. The composition has reduced global warming potential for the mobile air-conditioning market. The composition maintains the desired properties and functionality.    DETAILED DESCRIPTION - A composition comprises Z-1,2-difluoroethylene and at least one compound selected from 2,3,3,3-tetrafluoropropene, Z-1,2,3,3,3-pentafluoropropene, E-1,2,3,3,3-pentafluoropropene, E-1,3,3,3-tetrafluoropropene, 3,3,3-trifluoropropene, difluoromethane, pentafluoroethane, 1,1,2,2-tetrafluoroethane, 1,1,1,2-tetrafluoroethane, 1,1,1-trifluoroethane, 1,1-difluoroethane, fluoroethane, 1,1,1,2,3,3,3-heptafluoropropane, 1,1,1,2,3,3-hexafluoropropane, 1,1,1,3,3,3-hexafluoropropane, 1,1,1,3,3-pentafluoropropane, propane, n-butane, isobutane, propylene, cyclopropane, n-pentane, isopentane, dimethylether, trifluoroiodomethane, and CF3SCF3. INDEPENDENT CLAIMS are included for the following:    (1) a method for replacing a refrigerant selected from R134a, R22, R12, R404A, R410A, R407C, R413A, R417A, R422A, R422B, R422C, R422D, R423A, R424A, R426A, R428A, R430A, R434A, R437A, R438A, R507A, and R502, in a system that uses, used, or was designed to use the refrigerant, involving adding to the system, the composition;    (2) a method of refrigeration, air-conditioning or heating involving the steps of evaporating and condensing the composition, where the composition functions as a refrigerant;    (3) a method of forming a foam involving adding to a foamable composition the composition; and reacting the foamable composition under conditions effective to form a foam;    (4) a process for producing aerosol products involving adding the composition to active ingredients in an aerosol container, where the composition functions as a propellant; and    (5) a process (P1) for recovering heat involving evaporating a liquid phase working fluid comprising the composition in a heat exchanger in contact with a system that produces heat thus producing a vapor phase working fluid and passing the vapor phase working fluid to an expander where mechanical energy is produced.