It’s one of life’s most frustrating ironies that Earth’s surface is over 70 percent water, but most of that is undrinkable. Desalination is an important technology that may help unlock more drinking water, and now two independent teams have developed new types of solar-powered desalination systems using very different mechanisms.
The first of the two new designs comes from researchers at MIT and Shanghai Jiao Tong University. The team says the multilayer system has an impressive overall efficiency of 385 percent, producing as much as 5.78 L (1.52 gallons) of clean water per square meter of solar-collecting area, which is more than twice the amount produced by similar systems.
Each of the layers, arranged vertically, has an important role to play in the process. First, there’s a transparent insulating layer that lets sunlight through to a black, heat-absorbing layer. That in turn passes the heat onto several layers of wicking material, which have sucked the water up from below. The water evaporates out of that layer and strikes another surface, where it condenses and drips off to be collected.