microfins, condensation, desuperheating
Typical condenser design model simply divides the heat rejection process into de-superheating, two-phase, and subcooling. By neglecting condensation in presence of superheated vapor, error can be introduced. Experimental data on superheated CO2 and R410A flow in horizontal microfin tubes of 6 mm inner diameter at reduced pressures from 0.55 to 0.95 are provided. Gradually increasing heat transfer coefficient, from when tube wall reaches saturation temperature, demonstrates the criteria of condensation occurrence and the proposed heat transfer model.