SOLMED: solar energy and polymers for seawater desalination

International audience Combining thermal solar energy and polymer materials allows seawater desalination while fossil fuels are saved and use of chemicals against fouling and corrosion is reduced. SOLar Multi-Effect Desalination (SOLMED) meets recommendations of the US National Research Council and Middle East Desalination Research Center of Oman regarding the future of water desalination. Water cost reduction and development of technologies with low environmental impact are the main guidelines of SOLMED. Thermal efficiency is at the heart of SOLMED. Process is based on low-temperature multi-effect distillation (LT-MED) powered by a thermal solar collector field, or better, by heat recovery at the outlet of a solar power plant. Heat transfer surfaces are made of thin wall polymer tubes to ensure a high thermal duty in spite of low thermal conductivity of polymers. Targeted capacities lie within 500-1,000 m(3)/d. The objective is to develop a LT-MED prototype made of polymers and to operate the system plugged to a solar heat source. To reach these objectives, SOLMED gathers a consortium of six partners, merging experts of thermal systems and components, experts in polymers and transformation, and engineering partners in the field of solar energy and processes. Social aspects are also taken into account through acceptability, sustainability, design, management of innovation, market, and life cycle assessment. SOLMED is a three years project funded by the French National Research Agency. The first step is to build a 10 m(3)/d prototype to bring a proof of concept. The prototype will be operated with a 100 kW peak solar heat source. Developments are related to the modeling of the process itself and its integration in a solar system including heat storage, thin-wall tubes fabrication, optimization of tubes fixing, investigations related to heat transfer, and hydraulic. Regarding polymer materials, the challenge is to combine high thermal rate with long lifetime. Commercial step has to consider new optimization approach, taking into consideration the whole process, including heat source.