R513A is a new azeotropic mixture made of R1234yf/R134a (56%/44%). Unlike pure R1234yf, R513A is non-flammable, and it can be used as replacement of R134a for medium and high temperature refrigeration systems.

The paper shows preliminary experimental results during R513A condensation inside a 4.0 mm OD microfin tube. The microfin tube has an inner diameter at the fin tip of 3.4 mm, it has 40 fins along the inner circumference, and each fin is 0.12 mm high. Tests are carried out for mass fluxes from 100 to 800 kg m^-2 s^-1, at saturation temperatures of 30 and 40 °C.

Experimental results are given in terms of heat transfer coefficient and frictional pressure drop. The range of operating conditions permitted to understand how the working parameters affect the thermal and hydraulic behavior of R513A condensing inside the microfin tube under investigation.

The results show the interesting thermal characteristics of R513A, which can be used in near future as replacement of the traditional R134a.