Heat transfer characteristics of R32, R410A and R1234yf during evaporation inside horizontal minichannel.

This study demonstrated two phase flow boiling heat transfer coefficient of R32, R410A and R1234yf in minichannels. The experimental data were measured in horizontal stainless steel tubes with the inner diameter of 1.5 mm. The testing conditions were varied as mass fluxes from 300 to 500 kg/m2s, the heat fluxes from 5 to 30 kW/m2, the saturation temperature of 10°C and the vapor quality from 0.1 to dry-out. The effects of mass flux, heat flux on the heat transfer coefficient were analyzed. The experimental results were also compared with some well-known heat transfer coefficient correlations. A modified correlations of heat transfer coefficient was developed with present experimental data.