Etude et conception d’un système de distillation membranaire intégré pour la purification de l’eau et la production d’énergie.

Abstract

This study investigates the modeling, simulation, and performance analysis of a solar-assisted direct contact membrane distillation (DCMD) system for freshwater production in arid and semi-arid regions. A dynamic co-simulation approach, combining TRNSYS for solar thermal modeling and MATLAB for detailed DCMD module modeling, was developed and validated under real climate conditions in Ain Témouchent, Algeria. The system integrates flat-plate solar collectors (2 to 6 m2), a 300- liter hot water storage tank, an auxiliary heater, and 0.5 m2 of PVDF flat-sheet membrane modules. The DCMD module, modeled using heat and mass transfer equations, allows for co-current and counter-current operation. The simulation included two configurations: a basic system without heat recovery and an enhanced system with an economizer to recover residual heat from the membrane outlet. The simulation results demonstrate the high performance and potential of the proposed solar integrated DCMD system for freshwater production. Membrane water production reached up to 13.57 kg/m2·h, with an average daily yield of 54.28 liters during the standard 8-hour operation window. The solar fraction peaked at 71%, and the solar collector efficiency reached a maximum of 63% in July, indicating strong alignment with seasonal solar resource availability. The annual performance simulations indicated the best balance between energy efficiency, water productivity. The economizer successfully recovered thermal energy from the membrane outlet stream, preheating the incoming feed and significantly reducing thermal losses. This improved the overall thermal efficiency by reusing the membrane outlet heat, reducing system losses, increasing effective temperature at the feed inlet. and a daily water production increased from 54.28 liters/day to approximately 100 liters/day, despite a reduction in operating time from 8 hours to just 5 hours a clear indication of a more efficient desalination process. The TRNSYS-MATLAB co-simulation framework proved to be a powerful and flexible tool for modeling, design, and performance optimization of solar-thermal desalination systems.