Introduction to solar desalination
Solar desalination is the use of solar radiation to desalinate water. Direct solar desalination uses the energy from the sun directly in the desalination – for example to heat the water. Decoupled solar desalination first generates electricity from the sun, then uses that electricity to power a desalination system.
Solar stills (distillers) are one of the earliest forms of desalination, using solar radiation to evaporate water which then condenses out on a cold surface.
Seawater greenhouses use mats wetted with saline water to humidify the greenhouse using either natural or forced ventilation.
Concentrated Solar Stills
Concentrated solar stills (CSS) use concentrated solar thermal collectors as the heat source for a thermal desalination process. In commercial CSS systems multiple effect distillation (MED) is used for the desalination. In the broadest terms, CSS systems desalinate a much greater volume of water per unit solar collection area than conventional solar stills.
Plasmonics is the use of solar radiation to excite metals. In the context of desalination, plasmonics results in very localised boiling on the lighted metal’s surface.
Decoupled solar desalination
Decoupled solar desalination (DCD) uses a solar power plant – typically photovoltaics – to generate electricity. This electricity is then used to power any form of desalination plant. Local DSD colocates the power generation and desalination steps. Remote DSD is more an accounting term in which all power used in the desalination process is balanced by solar power plants, installed for the purpose, elsewhere.