Dropwise and filmwise condensation of water vapor on gold

A pure gold tube was found to give filmwise condensation in the absense of organic contamination in a flow sitution simulating that found in seawater conversion plants. A sensitive test for the presence of organic contamination has been developed. The gold tube, promoted by paraffinic thio‐silane or mercaptan, gave 100% excellent dropwise condensation. Overall heat transfer coefficients are reported for filmwise and dropwise condensation. The steamside heat transfer coefficient with dropwise condensation was estimated to be over 0.2 MW/m 2 ‐°C (35,000 B.t.u./hr‐ft 2 ‐°F) at the 95% confidence level. Gold plated tubes Supplied by P. Tomalin and S. Mulford of the Office of Saline Water, USDI. gave 95% filmwise condensation after one week of operation in a clean, once‐through system.