An experimental study of flow condensation with non-azeotropic refrigerant mixtures of R32/R134a in microchannels

Abstract

This paper aims at experimental study of heat transfer during flow condensation of a binary mixture of refrigerants R32 and R134a in a microchannel heat exchanger. The experiments were performed in a horizontal microchannel condenser with one-sided cooling. The condenser was based on 20 × 40 mm copper plate containing 21 rectangular microchannels with a section of 335 × 930 μm. The non-azeotropic mixture of R32/R134a refrigerants at molar concentrations of the initial mixture of 35% / 65% and 65% / 35% was used as a working fluid. The experiments were carried out in the mass flow range from 100 to 300 kg/m2 s and with a vapor quality from 0.05 to 1.0 at an absolute pressure in the system of up to 14 bar. The data obtained are compared with the prediction according to Silver – Bell & Ghaly method.