Condensation heat transfer and pressure losses of high- and low-pressure refrigerants flowing in a single circular minichannel

A 0.96 mm circular minichannel is used to measure both heat transfer coefficients during condensation and two-phase pressure losses of the refrigerants R32 and R245fa. Test runs have been performed at around 40°C saturation temperature, corresponding to 24.8 bar saturation pressure for R32 and 2.5 bar saturation pressure for R245fa. The pressure drop tests have been performed in adiabatic flow conditions, to measure only the pressure losses due to friction. The heat transfer experimental data are compared against predicting models to provide a guideline for the design of minichannel condensers.