CHAPTER 9 SOLAR DESALINATION John H. Lienhard,1,¤ Mohamed A. Antar,2 Amy Bilton,1 Julian Blanco,3 & Guillermo Zaragoza4 1 Center for Clean Water and Clean Energy, Room 3-162, Department of Mechanical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139-4307, USA 2 Department of Mechanical Engineering, King Fahd University of Petroleum and Minerals, Dhahran, Saudi Arabia 3 Plataforma Solar de Almeria, Carretera de Senes s/n, 04200 Tabernas (Almeria), Spain 4 Visiting Professor of Electrical Engineering, King Saud University, Riyadh, Saudi Arabia ¤Address all correspondence to John H. Lienhard E-mail:
[email protected] In many settings where freshwater resources or water supply infrastructure are inadequate, fossil energy costs may be high whereas solar energy is abundant. Further, in the industri- alized world, government policies increasingly emphasize the replacement of fossil energy by renewable, low-carbon energy, and so water scarce regions are considering solar-driven desalination systems as a supplement to existing freshwater supplies. Even in regions where petroleum resources are copious, solar-driven desalination is attractive as a means of con- serving fossil fuel resources and limiting the carbon footprint of desalination. Finally, in set- tings that are remote and ‘off-the-grid,” a solar driven desalination system may be more eco- nomical than alternatives such as trucked-in water or desalination driven by diesel-generated electricity. This article reviews various technologies that couple thermal or electrical solar energy to thermal or membrane based desalination systems. Basic principles of desalination are reviewed. Solar stills and humidification-dehumidification desalination systems are dis- cussed.