This paper reports an experimental investigation of heat-transfer behavior of binary mixtures of Refrigerants 13 and 12. It is well known that such mixtures can offer great flexibility in temperature of obtainable temperatures for refrigerating systems, as well as thermodynamic advantages. This study was undertaken to provide useful data for the research and development engineer in the refrigeration industry.

Local heat-transfer coefficients during forced convection boiling of binary mixtures of Refrigerants 13 and 12 inside a horizontal tube have been experimentally determined. They were found to increase with the increase of flow rate, heat flux, and vapor quality. This trend is the same as that for pure refrigerants. Further, the variation of the local heat-transfer coefficient with the mixture composition has been reported. Comparison has also been made between experimentally determined average heat-transfer coefficients and those calculated by the commonly accepted Bo.Pierre correlation for average heat-transfer coefficient, incorporating the fluid properties for pure R-12 and four compositions of binary mixtures of Refrigerants 13 and 12.