Process modeling for economic optimization of a solar driven sweeping gas membrane distillation desalination system

Water scarcity is especially impactful in remote and impoverished communities without access to centralized water treatment plants. In areas with access to a saline water source, point-of-use desalination by solar-driven membrane distillation (MD) is a possible method for mitigating water scarcity. To evaluate the applicability of MD, a comprehensive process model was developed and used to design an economically optimal system. Thermal energy for distillation was provided by solar thermal collectors, and electricity was provided using photovoltaic collectors. Distillation was performed using sweeping-gas membrane distillation. The cost of water in the optimized system was approximately $85/m³. Membrane modules and solar thermal collectors made up the largest portion of the cost. Neither thermal nor electrical energy storage was economical within current technologies. The model developed provides a template to optimize MD membrane characteristics specialized for point-of-use applications.