Water security is a serious global problem. Nearly 1.5 billion people – including almost half a billion children – live in areas of high or extremely high water vulnerability. Less than 3% of the world’s water is fresh and demand for it is rising with increasing population growth, urbanization, and growing water needs from a range of sectors.
Researchers at the University of South Australia have developed a promising new technique that could help reduce or eliminate water stress for millions of people. The technique uses highly efficient solar evaporation to obtain fresh water from seawater, brackish water, or even contaminated water. According to the researchers, their technique can deliver enough daily fresh drinking water for a family of four from just one square meter of source water.
Solar evaporation has been the focus of a great deal of effort in recent years, but it has generally been found to be too inefficient to be practically useful. The new technique overcomes those inefficiencies and can deliver fresh water at a fraction of the cost of existing technologies like reverse osmosis.
The system utilizes a highly efficient photothermal structure that sits on the surface of a water source and converts sunlight to heat, focusing energy precisely on the surface to rapidly evaporate the uppermost portion of the liquid. The technique prevents any loss of solar energy and even draws additional energy from the bulk water and surrounding environment.
The system is built entirely from simple, everyday materials that are low cost, sustainable, and easily obtainable.
The technology has the potential to provide a long-term clean water solution to people who can’t afford other systems, and these are the places where such solutions are most needed.
Photo, posted November 13, 2016, courtesy of Steve Austin via Flickr.