Seawater reverse osmosis desalination driven by a solar Organic Rankine Cycle: Design and technology assessment for medium capacity range

Desalination driven by renewable energies is an interesting technology in isolated areas. Its feasibility and reliability are guaranteed by innumerable designs implemented and experiences carried out, mainly focused on small capacity systems. This paper aims to design the optimum solar desalination system for nominal capacities of about 1000–5000 m3/d. A seawater reverse osmosis desalination unit powered by an Organic Rankine Cycle heated by a parabolic trough solar field is designed. The Rankine cycle proposed is designed to provide the total electricity demand of the desalination plant. Therefore, the system would be suitable for a stand-alone operation due to all the energy requirement is supplied by the solar system. Moreover, a general assessment of the proposed design in comparison to competitor technologies is provided.

► Desalination driven by renewable energies is an attractive combination in many regions. ► Only mature and efficient renewable energy technologies are suitable for medium to large scale desalination. ► The solar desalination system recommended by the authors is a reverse osmosis unit powered by an Organic Rankine Cycle. ► The authors describe an optimised design of a medium capacity seawater desalination plant driven by this kind of cycle. ► A general assessment of the proposed design in comparison to competitor technologies is provided.