| Condensation heat transfer coefficients of HFC245fa on a horizontal plain tube Ki-Jung Park, Dong Gyu Kang, Dongsoo Jung
The Journal of Mechanical Science and Technology, vol. 24, no. 9, pp.1911-1917, 2010
Abstract : 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℃ with a wall subcooling temperature of 3-8℃. 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.
Keyword :
Condensation heat transfer; Heat transfer coefficients; HFC245fa; Ozone layer depletion
|
