Dynamic solar-powered multi-stage direct contact membrane distillation system: Concept design, modeling and simulation

This paper presents a theoretical analysis of the monthly average daily and hourly performances of a solar-powered multi-stage direct contact membrane distillation (SMDCMD) system with an energy recovery scheme and dynamic operating system. Mid-latitude meteorological data from Busan, Korea is employed, featuring large climate variation over the course of one year. The number of module stages used by the dynamic operating scheme changes dynamically based on the inlet feed temperature of the successive modules, which results in an improvement of the water production and thermal efficiency. The simulations of the SMDCMD system are carried out to investigate the spatial and temporal variations in the feed and permeate temperatures and permeate flux. The monthly average daily water production increases from 0.37 m3/day to 0.4 m3/day and thermal efficiency increases from 31% to 45% when comparing systems both without and with dynamic operation in December. The water production with respect to collector area ranged from 350 m2 to 550 m2 and the seawater storage tank volume ranged from 16 m3 to 28.8 m3, and the solar fraction at various desired feed temperatures from 50 °C to 80 °C have been investigated in October and December.