Theoretical Investigation into the Dynamic Performance of a Solar-Powered Multistage Water Gap Membrane Distillation System

This article introduces a dynamic theoretical analysis, which is not available in the literature, for the average hourly and monthly performances of a solar-driven multistage water gap membrane distillation system. Based on simultaneous solutions of the combined heat and mass transfer equations using EES software, the dynamic model successfully predicted the average hourly and monthly output from the system. The mid-latitude meteorological data from Dhahran city, Saudi Arabia, are employed in this analysis. This analysis is carried out to examine the variations of the system productivity and energy efficiency with the operating and design parameters of the integrated system, which include the average monthly and hourly solar radiation, the number of the MD units and the number of solar collectors that are used for water heating. Results reveal that an eight-stage MD system with three solar collectors can produce up to 70 L/day of freshwater. The integrated solar MD system is able to effectively improve energy efficiency, with a maximum GOR of 0.95.