Sustainable Water Production: Solar Energy Integration in Multi-Effect Desalination Plants

This study addresses the increasing demand for sustainable water production by investigating the integration of solar energy into a multi-effect desalination (MED) plant located in Zuara, Libya. It is acknowledged that regions with high water demand frequently experience elevated levels of solar radiation; thus, this approach seeks to reduce dependence on fossil fuels and mitigate harmful emissions. Three operational modes were analyzed and compared: (1) daytime-only solar operation, (2) hybrid solar-boiler operation, and (3) solar operation with thermal energy storage. A validated mathematical model, informed by real empirical data, was used to assess energy and exergy efficiencies as well as production costs per cubic meter of desalinated water. The results indicate a trade-off between cost-effectiveness and environmental impact. The fossil fuel-based mode demonstrated the highest energy efficiency but also produced the greatest pollution. Conversely, the solar-only daytime mode, while free of emissions, was the costliest (USD 1.4/m3) due to its limited operational hours. The hybrid mode offered a compromise, presenting lower costs (USD 0.79/m3) and moderate land use, yet it still relied on fossil fuels. The thermal storage mode facilitated continuous, clean desalination at a higher cost (USD 0.97/m3) and required the largest solar field area. This study demonstrates the potential of solar-powered MED plants for sustainable water production, particularly in regions characterized by abundant sunlight and water scarcity. Furthermore, this research provides a comprehensive framework for selecting the optimal operational mode based on specific priorities, such as minimizing environmental impact, reducing costs, or maximizing operational flexibility.