Experimental analysis on condensation heat transfer of propane and a propane/CO2 mixture in a minichannel.

In the refrigeration industry, natural fluids are seen as the best option for future applications. Their low environmental impact and good thermodynamic properties make them suitable for meeting regulatory restrictions while ensuring good performance. This study examines the condensation heat transfer of propane and a non-azeotropic mixture of propane and carbon dioxide in a 2.76 mm diameter channel. The condensation heat transfer coefficients have been measured at saturation temperature equal to 40°C and compared with those obtained in a channel with internal diameter equal to 0.96 mm. The R290/CO2 mixture used has a 95/5% mass composition and shows a temperature glide equal to 10.3 K at 15.8 bar. The new local heat transfer coefficient data obtained with the mixture have been compared with those of propane. The comparison between experimental data and the predictions from some semi-empirical correlations is also assessed.