R32/R125/R134a mixtures are zeotropic, having vapour compositions that are different from the liquid compositions. These differences can lead to changes in refrigerant circulating compositions, depending on system design features such as suction line accumulators and refrigerant on the shell side of flooded evaporators. Values for inside-tube and outside-tube heat transfer coefficients are also affected by the different vapour compositions. These factors lead to the opportunity for increased heating capacity of heat pumps with accumulators but to reduced capacity and energy efficiency in water chillers having flooded evaporators.

KEYWORDS: year 1997, Performance, refrigerants, R32, R125, R134a, mixtures, R22, fluorocarbons, heat transfer coefficient, heat pumps, testing, measuring, chillers, heat flow, thermal capacity, evaporators