Flow condensation in smooth and micro-fin tubes with HCFC-22, HFC-134a andHFC-410A refrigerants part II: Design equations

An empirical study of single-phase convection and how condensation heat tra nsfer in horizontal tubes was conducted. Three refrigerants (HCFC-22, HFC-1 34a and HFC-410A), a smooth tube, and three micro-fin tubes (axial, helical and crosshatch enhancement) were examined. Commonly cited correlations wer e evaluated, utilizing the experimental data obtained in Part I of this stu dy. Although these correlations had fairly good agreement with HCFC-22 and HFC-134 results, ail of them failed to predict HFC-410A performance. A modi fied Shah equation was developed for smooth tube annular flow condensation, which overcomes the shortcomings of the existing correlations. Furthermore , design equations were developed for single-phase heat transfer and two-ph ase condensation with all three micro-fin tubes investigated, and covering all three refrigerants tested.