I first heard about this development in a BBC podcast of Science in Action where Dr. Varanasi was interviewed.
A new system devised by MIT engineers could provide a low-cost source of drinking water for parched cities around the world while also cutting power plant operating costs.Most people are aware of the way fog or mist condenses into water droplets on a mesh or screen (or on the bodies of insects in the Namib Desert or on redwood trees). A power plant tower is basically creating distilled water - all you have to do is harvest it. The principle has been demonstrated in a laboratory setting; now it's being scaled up. It's cheaper by a log power than fashioning new desalination plants.
About 39 percent of all the fresh water withdrawn from rivers, lakes, and reservoirs in the U.S. is earmarked for the cooling needs of electric power plants that use fossil fuels or nuclear power, and much of that water ends up floating away in clouds of vapor. But the new MIT system could potentially save a substantial fraction of that lost water — and could even become a significant source of clean, safe drinking water for coastal cities where seawater is used to cool local power plants.
The principle behind the new concept is deceptively simple: When air that’s rich in fog is zapped with a beam of electrically charged particles, known as ions, water droplets become electrically charged and thus can be drawn toward a mesh of wires, similar to a window screen, placed in their path. The droplets then collect on that mesh, drain down into a collecting pan, and can be reused in the power plant or sent to a city’s water supply system.
The system, which is the basis for a startup company called Infinite Cooling that last month won MIT’s $100K Entrepreneurship Competition, is described in a paper published today in the journal Science Advances, co-authored by Maher Damak PhD ’18 and associate professor of mechanical engineering Kripa Varanasi. Damak and Varanasi are among the co-founders of the startup, and their research is supported in part by the Tata Center for Technology and Design.