The present invention relates to compositions for use in refrigeration, air-conditioning, and heat pump systems wherein the composition comprises a fluoroolefin and at least one other component. The compositions of the present invention are useful in processes for producing cooling or heat, as heat transfer fluids, foam blowing agents, aerosol propellants, and fire suppression and fire extinguishing agents.

A working fluid composition for a refrigerating machine comprising: a refrigerating machine oil containing at least one lubricating base oil selected from a mineral oil and a synthetic oil, and at least one phosphorus compound selected from a mono(alkylphenyl) diphenyl phosphate having a C3-C5 alkyl group and a di(alkylphenyl) phenyl phosphate having two C3-C5 alkyl groups, wherein a content of the phosphorus compound is 0.01 to 5% by mass based on a total amount of the refrigerating machine oil; and a hydrocarbon refrigerant having 2 to 4 carbon atoms.

The present invention relates to heat transfer compositions comprising 1234yf refrigerant, PAG lubricant and dispersant and to methods of retrofitting R134a MAC systems with using such compositions.