Experimental study of R1234yf/R601a condensation characteristics in mini-channel

This study presents a systematic experimental investigation on the condensation heat transfer, frictional pressure drop, and entropy generation characteristics of zeotropic mixtures R1234yf/R601a in a horizontal mini-channel with an inner diameter of 2 mm. Experiments were conducted over a mass flux range of 200–600 kg·m⁻²·s⁻¹, saturation pressures from 0.5 to 1.5 MPa, and across the entire vapor quality range. The effects of mass flux, vapor quality, saturation pressure, and mixture composition were systematically analyzed. Results show heat transfer degradation, which becomes more pronounced at higher vapor qualities. Frictional pressure drop generally increases with vapor quality but decreases beyond a vapor quality of 0.75 under certain conditions. Total entropy generation increases first and then decreases with mass flux. New heat transfer and frictional pressure drop correlations were developed, showing mean absolute relative deviations of 9.63% and 12.67%, respectively, for R1234yf/R601a mixtures. These correlations also predict 85.36% of heat transfer data and 87.70% of pressure drop data from literature within ±30% error. The total entropy generation calculated using the new correlations agrees well with experimental results.