Lin W.W.Lee D.J.Peng X.F.2019-05-142019-05-14200103681653https://scholars.lib.ntu.edu.tw/handle/123456789/407857This study performed second-law analysis on saturated FC - 22 vapor flowing through and condensed in horizontal cooling tubes. An optimum Reynolds number existed over the parametric range investigated for the single tube case at which the entropy generated at a minimum rate. For the multi-tube cases, on the other hand, no optimal Reynolds number was identified subject to constant surface-area constraint. Furthermore, there was an optimal cooling temperature that generated a minimum of entropy for a given duty. The present phase-change system was inherently different in thermodynamic performance from the single-phase convective system intensively discussed in literature works.Cooling tempearatureFilm condensationOptimal Reynolds numberSecond-lawjournal article2-s2.0-0035049001https://www.scopus.com/inward/record.uri?eid=2-s2.0-0035049001&partnerID=40&md5=b828ffdcc7e844d3492d3e27fa796a50