Experimental investigation during condensation of R-600a vapor over single horizontal integral-fin tubes

•Heat flux increases as wall sub-cooling temperature, ΔTf increases.•Heat transfer coefficient reduces with rise in wall sub-cooling temperature, ΔTf.•1102 fpm integral fin tube shows the highest HTC.•1260 fpm integral fin tube shows the lowest HTC.

In this study, condensation heat transfer coefficients (HTCs) of refrigerant R-600a (iso-butane) over a horizontal smooth tube of outer diameter 19 mm and five integral fin tubes of different fin-densities (945, 1024, 1102, 1181, and 1260 fpm) were determined at vapor temperature of 39 ± 0.5 °C with different wall sub-cooling temperatures in a range of 3–12 °C. Like other refrigerants, condensation heat transfer coefficients of R-600a showed the same trend with wall sub-cooling where condensation HTCs decrease with the rise in wall sub cooling temperatures. The heat flux was 11–20 kW/m2 for the plain tube and 28–82 kW/m2 for integral fin tubes. Based upon the data taken in this study, different graphs were plotted varying different parameters to show their dependency on other parameters. The experimental data were also validated by comparing them against different models.