A new siphon-based thermal desalination system can now transform salty seawater into clean drinking water—faster, cheaper, and more reliably than existing methods.

Traditional solar stills, which mimic nature’s water cycle, have long been promoted as simple water purifiers. However, they face two persistent challenges:

            •           Salt buildup, where crusts form on evaporator surfaces, blocking water flow.

            •           Scaling limits, as wicking materials can only lift water about 10–15 cm, restricting system size and output.

A research team from the Indian Institute of Science (IISc) has addressed both challenges using a deceptively simple principle—siphonage.

At the heart of their system is a composite siphon: a fabric wick paired with a grooved metallic surface. The fabric draws salty water from a reservoir, while gravity ensures a smooth, continuous flow. Instead of allowing salt to crystallize, the siphon flushes it away before buildup occurs.

Fig 1. Schematic of a multistage siphon desalination system

The water spreads as a thin film across the heated metal surface, evaporates, and then condenses just two millimeters away onto a cooler surface. This ultra-narrow air gap significantly enhances efficiency, producing more than six liters of clean water per square meter per hour under sunlight—several times higher than conventional solar stills.

By stacking multiple evaporator–condenser pairs, the device recycles heat repeatedly, squeezing maximum output from each ray of sunshine.

The desalination unit is low-cost, scalable, and sustainable, relying only on simple materials such as aluminum and fabric. It can run on solar energy or waste heat, making it suitable for off-grid communities, disaster zones, and arid coastal regions. Notably, it can also handle extremely salty water (up to 20% salt) without clogging—a major advance in brine treatment.

Fig 2. A multistage siphon desalination system tested in the laboratory.

Fig 3: A multistage siphon desalination system tested at the outdoor conditions.

This innovation, published in Desalination and supported by India’s Department of Science and Technology (DST), could help secure safe drinking water for millions in water-stressed regions. From small villages to island nations, the siphon-powered desalination system may finally make the ocean a dependable source of fresh drinking water.

In the researchers’ words, it is about “scalability, salt resistance, and simplicity”—a winning trio for a thirsty world.

***

NKR/PSM

(Release ID: 2172767) Visitor Counter : 555