In News:

• Researchers at the Indian Institute of Science (IISc), Bengaluru, have developed an innovative siphon-powered thermal desalination system that can transform seawater into potable water faster, cheaper, and more reliably than existing technologies.
• The breakthrough addresses long-standing challenges in solar desalination, such as salt buildup and limited wicking height, offering a scalable solution for water-stressed regions.

How the Siphon-Powered System Works:

• Composite Siphon: A fabric wick paired with a grooved metal surface continuously draws seawater from a reservoir.
• Gravity Flow: Ensures smooth movement and flushes away salt before crystallization occurs.
• Thin-Film Evaporation: Water spreads as a thin layer on heated metal surfaces and evaporates efficiently.
• Ultra-Narrow Air Gap: Vapor condenses just 2 mm away on a cooler surface, enhancing efficiency.
• Multistage Stacking: Multiple evaporator–condenser pairs recycle heat, maximizing water output.

Key Features and Advantages:

• High Efficiency: Produces more than 6 litres of potable water per square metre per hour under sunlight, significantly higher than conventional solar stills.
• Low-Cost Materials: Uses aluminum and fabric, making it affordable and easy to deploy.
• Energy Flexibility: Operates on solar energy or waste heat, enabling off-grid functionality.
• Durability: Can handle highly saline water (up to 20% salt) without clogging.
• Scalability: Suitable for villages, coastal areas, disaster zones, and island nations.

Significance:

• Water Security: Provides a sustainable solution for drinking water scarcity in remote and off-grid regions.
• Innovation Leap: Overcomes technical limits of traditional solar stills, particularly salt scaling and wicking height.
• Sustainable Development: Eco-friendly, low-cost, and aligned with SDG 6 (Clean Water and Sanitation).

Supported by India’s Department of Science and Technology (DST) and published in Desalination, this technology could make the ocean a reliable source of fresh water for millions, emphasizing simplicity, salt resistance, and scalability as its core strengths.