The theoretical predictions of pure water productivity in a parallel-plate direct contact membrane distillation (DCMD) module using roughened-surface flow channel for enhancement of heat transfer were obtained under countercurrent-flow operations, and the improvements of device performance for increasing the pure water productivity in saline water desalination were achieved as compared that to the concurrent-flow operation. The roughened surface was fabricated using siphonic-blasting with aluminum oxide ( 2 3 Al O ) sand grains and arc spraying for Ni film coating, and correlated to predict the heat transfer coefficient for the DCMD device with using roughened-surface channels. The pure water productivity and temperature distributions of both hot and cold feed streams are represented graphically with the feed velocity and the inlet saline temperature as parameters. Both effects of flow pattern and roughened surface have demonstrated the technical feasibility and up to 46.39% of performance enhancement was obtained for the countercurrent-flow DCMD system. The influences of operation and design parameters on the pure water productivity with the expense of energy consumption are also discussed.
