Simultaneous Environmental and Economic Optimization of Reverse Osmosis Plants Coupled with Solar Rankine Cycles

This work addresses the design of seawater desalination plants that integrate reverse osmosis, Rankine cycles and solar collectors. The design task is formulated as a multiobjective mixed-integer nonlinear programming problem (MINLP) that considers the simultaneous minimization of cost and environmental impact given a certain water demand to be fulfilled. The environmental performance is quantified following life cycle assessment (LCA) principles. A case study that considers weather data of Tarragona (Spain) is used to illustrate the capabilities of the approach. By applying the epsilon constraint method, a set of Pareto solutions representing the optimal trade-off between both conflicting objectives is generated. We show that coupling seawater desalination with solar collectors leads to both, environmental and economical benefits. The systematic tool presented herein is intended to guide decision-makers towards the adoption of more sustainable technological alternatives for seawater desalination.