Super-Efficient Solar Steam Technique

Rice University scientists have unveiled a new technology that uses nanoparticles to convert solar energy directly into steam. The new 'solar steam' method is so effective, it can produce steam from icy cold water. Steam is one of the world's most widely used industrial fluids. About 90 percent of electricity is produced from steam, and it is also used to sterilize medical waste and surgical instruments and to purify water. The new technology has an overall energy efficiency of 24 percent. Photovoltaic solar panels, by comparison, typically have an overall energy efficiency around 15 percent. The team expects the technology will first be used in sanitation and water-purification applications in the developing world.

Transcript

00:00:00 [Music] the 90% of electricity you use is generated by steam but we're looking at is a different way of making steam what we have here is a new way to make steam using sunlight and nanoparticles well it doesn't require us to actually boil water so this is a radically new way to harvest solar energy and to use it in a very very general way so steam

00:00:31 is extremely valuable of course the Industrial Revolution was based on steam you can use steam to make electrical power but you can also use it for other applications like sanitation or desalination so there's a lot of interesting applications that might have a tremendous benefit in the developing world as well as applications here at home so normally we think of steam is

00:00:56 something that is the boil water it's a standard thing people have done it for thousands and thousands of years in the same way you put a heat source underneath and you boil water we're boiling water in a radically different way we are taking sunlight and nanoparticles that absorb the solar spectrum and we shine light on the nanoparticles immersed in water they

00:01:18 will absorb the light and convert the light to heat [Music] so this is actually quite general we've used metallic particles and we've also used conductive carbon particles what's important is that the particles absorb light over the cross the solar spectrum the steam production works very well for all of those types of nanoparticles the

00:01:40 efficiencies are very similar basis and we demonstrated that in a video where we actually show we start with water with nanoparticles inside and we sit it in an ice bath this is a frenum plastic lens that will concentrate the light in a spot on a spot shine light on the nanoparticles and they heat up and they produce steam even though the water in the solution is

00:02:12 at the freezing point and so that steam that we produce it is done at an extremely high efficiency between 80 and 90 percent of the energy that's absorbed from the Sun is actually converted to steam by the nanoparticles in this process from the initial very small-scale lab experiments that we did outdoors we've now the support of the Bill and Melinda Gates Foundation we've

00:02:35 been able to build the solar collectors like this and several other geometries that allow us to really build a platform that might for example serve the Sanitation needs of an entire family you