Condensation heat transfer coefficients of HFC245fa on a horizontal plain tube

Condensation heat transfer coefficients (HTCs) of HCFC22, HCFC123, HFC134a and HFC245fa are measured on a horizontal plain tube 19.0 mm outside diameter. All data are taken at the vapor temperature of 39°C with a wall subcooling temperature of 3–8°C. Test results show the HTCs of newly developed alternative low vapor pressure refrigerant, HFC245fa, on a smooth tube are 9.5% higher than those of HCFC123, while they are 3.3% and 5.6% lower than those of HFC134a and HCFC22, respectively. Nusselt’s prediction equation for a smooth tube underpredicts the measured data by 13.7% for all refrigerants, while a modified equation yielded 5.9% deviation against all measured data. From the view point of environmental safety and condensation heat transfer, HFC245fa is a long-term good candidate to replace HCFC123 used in centrifugal chillers.