Super-Efficient Solar-Energy Technology: ‘Solar Steam’ So Effective It Can Make Steam from Icy Cold Water

Nov. 19, 2012 — Rice University scientists have unveiled a revolutionary new technology that uses nanoparticles to convert solar energy directly into steam. The new "solar steam" method from Rice's Laboratory for Nanophotonics is so effective it can even produce steam from icy cold water. The technology's inventors said they expect it will first be used in sanitation and water-purification applications in the developing world. The efficiency of solar steam is due to the light-capturing nanoparticles that convert sunlight into heat. When submerged in water and exposed to sunlight, the particles heat up so quickly they instantly vaporize water and create steam. "We're going from heating water on the macro scale to heating it at the nanoscale," Halas said. "Our particles are very small -- even smaller than a wavelength of light -- which means they have an extremely small surface area to dissipate heat. This intense heating allows us to generate steam locally, right at the surface of the particle, and the idea of generating steam locally is really counterintuitive." Using a lens to concentrate sunlight onto the near-freezing mixture in the tube, Neumann showed she could create steam from nearly frozen water.