Performance enhancement of permeate gap membrane distillation system augmented with impeller

This research presents an assessment of a novel permeate gap membrane distillation (i-PGMD) desalination system. The investigated i-PGMD module involved the installation of an impeller inside the condensation chamber to promote turbulent dissipation rate and enhance mass and heat transfer characteristics of the system. The performance of the impeller enhanced PGMD unit (i-PGMD) is compared with the conventional PGMD without the installed impeller (PGMD). Results showed that the installed impeller greatly improved the system's energy efficiency and flux. The i-PGMD unit recorded the best flux, gained output ratio (GOR), and specific thermal energy consumption (STEC) of 181.08 kg/m²h, 0.59, and 1129.27 kWh/m³, respectively, while the PGMD unit attained the best flux, GOR, and STEC of 94.01 kg/m²h, 0.51, and 1302.6 kWh/m³, respectively. Furthermore, the impeller speed greatly influenced the performance of the i-PGMD system. Large gap width was found to have a negligible adverse effect on the i-PGMD module performance. The i-PGMD unit was found to be less sensitive to the salinity of the feed when compared to the PGMD configuration.