Condensation heat transfer characteristics of CO2 in a horizontal smooth- and microfin-tube at high saturation temperatures

► The condensation heat transfer experiments of CO2 were carried out in a horizontal smooth- and microfin-tube. ► The average heat transfer enhancement factor is approximately from 1.006 to 1.48. ► Cavallini et al. and Kondou and Hrnjak correlation agree with present data in the microfin- and smooth-tube.