Forced convective condensation heat transfer characteristics of nonazeotropic mixtures of R32/ R134a in a horizontal tube were experimentally investigated

with six different R32 mass fractions ranged from 0 to 60%. Nearly 2000 local - average heat transfer coefficients were taken. The measured heat transfer coefficients were compared with those of the pure R22 and R134a. When compared on an equal mass flux basis

the R32/R134a mixture with about 20% R32 mass fraction had the lower heat transfer coefficient than those of the other mixtures

and those of pure R22 and R134a. The results also revealed considerable degradation of heat transfer coefficients of R32/R134a mixtures

when compared with the linearly interpolated values between the two pure components.