In-tube condensation heat transfer of refrigerant mixtures

Heat transfer coefficient and pressure-drop data were taken during in-tube condensation of refrigerant mixtures in a smooth copper tube. The data were taken at 30C and 40C. Five nonazeotropic refrigerant mixtures and pure R-125 were tested and compared against baseline data for R-22. Four different mass fluxes ranging from 125 to 375 kg/sm2 were tested. The heat transfer coefficients of all the refrigerants decreased with increasing temperature. Also, all the refrigerants tested had lower heat transfer coefficients than R-22 when compared on an equal heating capacity basis. The equal heating capacity basis makes it easier to compare refrigerants with widely different enthalpies of vaporization.

In-tube condensation heat transfer of refrigerant mixtures Conference Paper