Cost-Effective Techniques for Enhancing Heat Transfer Rate in Steam Condensation

Abstract

Two different cost-effective techniques were used to enhance the condensation heat transfer rate of steam over a horizontal copper (99.9% Cu, 0.1% P) tube surface period. The first technique was using self-assembled monolayers (SAMs), and the second technique was using small amounts of heat transfer additives. Results of the experimental investigations done using these two techniques are presented. The use of SAMs of n-octadecyl mercaptan promotes dropwise condensation, which facilitates the deposition of desirable films that are only as thick as the length of composite molecules. When compared to complete filmwise condensation, the SAM coating increased the condensation heat transfer rate by a factor of 3 for copper surfaces in a horizontal tube configuration. Using effective additives, the condensation heat transfer coefficient can be enhanced as much as 1.4 times as compared to operating without additives. The steam condensation, which occurred in our experiments using effective additives, was mostly dropwise