In the face of escalating global water scarcity, science has been tirelessly searching for sustainable solutions to quench the world’s thirst. In a significant stride towards addressing this universal crisis, a team of researchers from the Indian Institute of Science (IISc) has pioneered a groundbreaking system that promises to enhance the availability of clean water, particularly in regions grappling with water shortages.
The world is in the throes of a water scarcity crisis, and the quest for clean, drinkable water has never been more urgent. As populations grow and climate change tightens its grip, the need for sustainable water purification methods has taken center stage. Enter thermal desalination, a water purification process that employs heat to evaporate water, remove impurities, and subsequently condense the vapor to yield fresh water.
The newly developed system from IISc is a notable innovation in the field of thermal desalination. This ingenuity harnesses the power of the sun to drive the desalination process, making it a green and renewable solution to the water scarcity problem. The essence of thermal desalination lies in its ability to effectively separate salt and other impurities from water through evaporation. This process can utilize different energy sources, from electricity to fossil fuels, to the more environmentally friendly option of solar power.
The IISc team has taken this concept and elevated it to new heights. They’ve designed a solar-powered desalination unit that not only prioritizes energy efficiency but also embraces cost-effectiveness and portability. Inspired by the traditional solar stills, where solar energy evaporates saltwater stored in large reservoirs, the team created a system where the resulting vapor condenses on a transparent roof and is collected for use.
Assistant Professor Susmita Dash from the Department of Mechanical Engineering elaborates on the design. The system, ideal for locations with sporadic electricity access, comprises a saline water reservoir, an evaporator, and a condenser, all encapsulated within an insulating chamber to mitigate heat loss to the surrounding environment.
Solar thermal energy is utilized to evaporate a small quantity of water wicked into the evaporator, which boasts a textured surface. Leveraging the capillary effect of microscale textures, the evaporator draws liquid into its narrow spaces, thereby boosting the system’s energy efficiency. The researchers meticulously experimented with diverse groove dimensions, spacing, and surface roughness to optimize this wicking process.
In a smart move to prevent water film formation during condensation, the condenser is designed with a mix of hydrophilic and superhydrophobic surfaces. The system further incorporates a mechanism to trap and reuse the heat released during condensation, which reduces the overall solar energy requirement. This conserved heat warms up the saltwater in a separate evaporator situated behind the condenser, thereby amplifying the system’s overall efficiency.
One of the standout features of this system is its adaptability. It has been engineered to accommodate the sun’s shifting positions throughout the day. It also showcases an impressive versatility, being capable of effectively desalinating a range of water types, from seawater to groundwater infused with dissolved salts, and even brackish water.
The focus for the IISc team now lies in escalating the system’s scale, enhancing its durability, and boosting the volume of drinkable water produced. This innovative system holds immense potential for addressing the global water crisis and can be a game-changer in providing an accessible and sustainable source of clean water to those who need it most.
