Power-saving water-cleaner sees desert success
A trial site has seen successful tests for a new way to desalinate water, making it drinkable for about half the cost of traditional methods.
A Californian company has been conducting field tests for a solar desalination technique, using a reflective film to focus the Sun’s rays on tubes containing mineral oil, suspended over the solar array.
The process is based on a new technology for gathering solar electricity, but in this case is used to heat up the oil, which is then transferred through evaporators full of contaminated water.
The heat of the mineral oil (at about 120 degrees) boils the water, with the resulting steam condensed into clean, drinkable water.
A pump is used to recycle excess steam using a chemical process rather than relying on an electricity-driven compressor, which nearly halves the number of solar collectors required.
In their pilot project, WaterFX produced 53,000 litres of purified water a day. If the plant was scaled-up to commercial size on the 31 acre plot, it would theoretically produce about 2714 megalitres per year.
The company also plans to store excess heat generated by the solar array in molten salt, WaterFX say this would feeding electricity back into the system and allowing it to operate 24 hours a day.
The application of this process is currently somewhat limited. It has been designed specifically to treat the water beneath the Californian surface, and most likely cannot cope with the much higher salinity of seawater, experts say.
Authorities say solar desalination allows groups access to an entirely new supply.
“This subsurface groundwater is a possible gold mine,” Dennis Falaschi, manager of the Panoche Water District said.
“You’re taking a water supply that is unusable now and you’re converting it to a usable source.”
More information is available at the company website.