The idea of using energy from the sun to evaporate and purify water is ancient. The Greek philosopher Aristotle reportedly described such a process more than 2,000 years ago.
Now, researchers are bringing this technology into the modern age, using it to sanitize water at what they report to be record-breaking rates.
By draping black, carbon-dipped paper in a triangular shape and using it to both absorb and vaporize water, they have developed a method for using sunlight to generate clean water with near-perfect efficiency.
“Our technique is able to produce drinking water at a faster pace than is theoretically calculated under natural sunlight,” says lead researcher Qiaoqiang Gan, PhD, associate professor of electrical engineering in the University at Buffalo School of Engineering and Applied Sciences.
As Gan explains, “Usually, when solar energy is used to evaporate water, some of the energy is wasted as heat is lost to the surrounding environment. This makes the process less than 100 percent efficient. Our system has a way of drawing heat in from the surrounding environment, allowing us to achieve near-perfect efficiency.”
The low-cost technology could provide drinking water in regions where resources are scarce, or where natural disasters have struck. The advancements are described in a study published on May 3 in the journal Advanced Science.
The project, funded by the National Science Foundation (NSF), was a collaboration between UB, Fudan University in China and the University of Wisconsin-Madison. UB electrical engineering PhD graduate Haomin Song and PhD candidate Youhai Liu were the study’s first authors.
Gan, Song and other colleagues have launched a startup, Sunny Clean Water, to bring the invention to people who need it. With support from the NSF Small Business Innovation Research program, the company is integrating the new evaporation system into a prototype of a solar still, a sun-powered water purifier.
Read more at University at Buffalo