A new model for refrigerant condensation inside enhanced tubes.

The aim of this work is to develop a procedure to compute the heat transfer coefficient during condensation of pure refrigerants and mixtures inside enhanced tubes. Cavallini et a. in 1993 and 1995 have proposed a new correlation for condensation inside low-fin and micro-fin tubes based on the Cavallini & Zecchin equation for smooth tube. In the present work this model has been extended to cross-grooved tubes, and compared against available data including zeotropic refrigerant mixtures; in this latter case the Silver and Bell & Ghaly correction has been used to account for mass transfer resistance. A set of around 300 data points have been considered relative to condensation inside low-fin, micro-fin and cross-grooved tubes in a wide range of operative conditions. The model proposed is able to reproduce the available experimental data with an absolute mean deviation of 15%.