Evaporation heat transfer characteristics of low GWP refrigerants
The present study investigated evaporation heat transfer coefficient and pressure drop of low GWP refrigerants such as R-446A, R-1234ze(E), and R-1233zd(E). The heat transfer coefficients were investigated by measuring outer wall temperature on a straight stainless tube with an inner diameter of 7.4mm and refrigerant temperature estimated by using refrigerant saturation pressure. The heat transfer
coefficients were measured for the quality from 0.1 to 0.9, the mass flux from 100 to 400 kg/m2s, the heat
flux from 10 to 30 kW/m2, and the saturation temperature from 5 to 10°C. The effect of mass flux on the evaporation heat transfer coefficient was not significant at low quality, while it was increased at high quality. The heat transfer coefficients of R-446A were larger than those of R-410A. The pressure drop of R-1233zd(E) showed the largest among three of them.