Engineers have developed a passive solar desalination system that mimics ocean circulation to produce freshwater from seawater. The design uses sunlight to heat saltwater and induce swirling eddies that evaporate water while rejecting salt. Testing showed a single stage could produce 5 liters of drinking water per hour. A scaled-up version is estimated to have a lifetime of several years without maintenance. As it requires no electricity, the system could produce water cheaper than tap water, potentially addressing water scarcity in coastal communities. An innovative aspect is how it circulates saltwater in a manner similar to ocean currents to effectively separate salt without clogging.

The passive design makes it well-suited for household water production in off-grid areas.