Solar stills function by evaporating clean water out of tainted water onto the clear top of a vessel, where it then runs down and collects beneath the vessel.
Solar stills are a primary technology for extracting potable water from tainted or salinated water, and while they’re useful in water-scarce regions, their technology is still relatively inefficient. Fortunately, a team of researchers from Russia’s Ural Federal University has reconceptualized the solar still to produce more clean water in less time at a higher volume.
Solar stills function by evaporating clean water out of tainted water onto the clear top of a vessel, where it then runs down and collects beneath the vessel, providing potable water. This new design uses the same basic principles, but utilizes a rectangular basin with a hinged transparent cover, within which is a horizontally-oriented black steel cylinder.
The cylinder uses solar power to rotate within the basin filled with water. The cylinder lifts a thin film of water as it turns, making it easier for that water to evaporate more quickly. The water is also continuously circulated through an external solar collector to keep it warmer, speeding up evaporation.
In trials, the new design was found to be 280 percent more efficient at producing drinking water than traditional stills. During hot summer months, this figure can be up to 300 to 400 percent. Now the researchers are working on scaling up the adoption of the technology by making it more affordable.
Source study: Ural Federal University – Evaluation of distilled water quality and production costs from modified solar still integrated with an outdoor solar water heater