The researchers from the Indian Institute of Science, Bengaluru, have invented a novel siphon-based thermal desalination system, which is capable of converting saline seawater into purified drinking water. The innovative system deploys a composite siphon, which is a fabric wick paired with a grooved metallic surface. The fabric draws seawater from a reservoir, with gravity ensuring a continuous flow. Unlike traditional solar stills, where salt crystallises, builds up on the surface of the evaporators and blocks the water flow, the siphons in this system flush away the salt.
In the next steps, water spreads like a thin film across the heated metal surface, evaporates, and condenses two millimetres away onto a cooler surface. This narrow air gap improves efficiency and produces around six litres of clean water per square meter per hour under sunlight. Another major benefit of the system is that it can also handle extremely salty water (with up to 20 per cent salt concentration) without clogging and thus advancing brine treatment. The system is potentially beneficial for water-stressed and off-grid regions.