On the potential of forward osmosis to energetically outperform reverse osmosis desalination
Author(s)
McGovern, Ronan Killian; Lienhard, John H
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We provide a comparison of the theoretical and actual energy requirements of forward osmosis and reverse osmosis seawater desalination. We argue that reverse osmosis is significantly more energy efficient and that forward osmosis research efforts would best be fully oriented towards alternate applications. The underlying reason for the inefficiency of forward osmosis is the draw-dilution step, which increases the theoretical and actual energy requirements for draw regeneration. As a consequence, for a forward osmosis technology to compete with reverse osmosis, the regeneration process must be significantly more efficient than reverse osmosis. However, even considering the optimisation of the draw solution and the benefits of reduced fouling during regeneration, the efficiency of an optimal draw regeneration process and of reverse osmosis are unlikely to differ significantly, meaning the energy efficiency of direct desalination with reverse osmosis is likely to be superior.
Date issued
2014-06Department
Massachusetts Institute of Technology. Abdul Latif Jameel World Water & Food Security Lab; Massachusetts Institute of Technology. Department of Mechanical EngineeringJournal
Journal of Membrane Science
Publisher
Elsevier
Citation
McGovern, Ronan K., and John H. Lienhard V. “On the Potential of Forward Osmosis to Energetically Outperform Reverse Osmosis Desalination.” Journal of Membrane Science 469 (November 2014): 245–50.
Version: Author's final manuscript
ISSN
03767388