It is possible to create steam within seconds by focusing sunlight on nanoparticles mixed into water, according to new research.
That observation, reported Monday by scientists at Rice University in Texas, suggests myriad applications in places that lack electricity or burnable fuels. A sun-powered boiler could desalinate seawater, distill alcohol, sterilize medical equipment and perform other useful tasks.
"We can build a portable, compact steam generator that depends only on sunlight for input. It is something that could really be good in remote or resource-limited locations," said Naomi Halas, an engineer and physicist at Rice who ran the experiment.
Whether the rig she and her colleagues describe would work on an industrial scale is unknown. If it does, it could mark an advance for solar-powered energy more generally.
"We will see how far it can ultimately go. There are certainly places and situations where it would be valuable to generate steam," said Paul Weiss, editor of the American Chemical Society's journal ACS Nano, which published the paper online in advance of the journal's December print publication.
The experiment is more evidence that nanoscale devices — in this case, beads one-tenth the diameter of a human hair — behave in ways different from bigger objects.
In the apparatus designed by the Rice team, steam forms in a vessel of water long before the water becomes warm to the touch. It is, in effect, possible to turn a container of water into steam before it gets hot enough to boil.
The research is being funded in part by the Bill & Melinda Gates Foundation in the hope it might prove useful in developing countries.