Monday, April 16, 2007

More Nano Power!!

Last week I told you all about the thrilling new nanotechnology development that may soon let your walking shoes power your iPod. It was such an exciting thing to learn that I know that you are dying to find out what else is going on in the wonderful world of nanotech. The yearning for more nano-knowledge is probably gnawing at you even now, and you feel very much like the desperate person who has been given a single tantalizing bite of cheesecake, only to see the rest of the delightful dessert accidentally upended onto an anthill. The suffering is, no doubt, intense. I simply can't be responsible for that kind of discomfort. The mere thought pains me, so today I will ease our mutual misery by bringing you news of yet another new nanoventure, only this one will be "better, stronger, faster," like Steve Austin after the upgrade. Last week's nanopower invention could run a cellphone; today's nanopower invention could possibly run satellites, or other spacecraft.

Our old friends, carbon nanotubes, having achieved near-universal-usefulness status with their extreme strength and lightness, are trying to further their foothold on ubiquity, by making their way into the realm of solar power. John Toon, writing at Georgia Tech Research News, explains how 3D solar cells, constructed using carbon nanotubes, could change the shape of solar, and thus of spacecraft power:

Unique three-dimensional solar cells that capture nearly all of the light that strikes them could boost the efficiency of photovoltaic (PV) systems while reducing their size, weight and mechanical complexity.

The new 3D solar cells capture photons from sunlight using an array of miniature "tower” structures that resemble high-rise buildings in a city street grid. The cells could find near-term applications for powering spacecraft, and by enabling efficiency improvements in photovoltaic coating materials, could also change the way solar cells are designed for a broad range of applications.

“Our goal is to harvest every last photon that is available to our cells,” said Jud Ready, a senior research engineer in the Electro-Optical Systems Laboratory at the Georgia Tech Research Institute (GTRI). “By capturing more of the light in our 3D structures, we can use much smaller photovoltaic arrays. On a satellite or other spacecraft, that would mean less weight and less space taken up with the PV system.”

You caught how the 3D nature of the little solar towers catches more of the light, right? Not only is there more surface area to absorb the photons, but the grid "traps" the light, rather than letting it bounce off the surface, as occurs now with standard solar panels. Light can bounce within the towers, allowing the new system to capture more of the photons--"virtually all of the light that strikes them." The towers also absorb sunlight coming from any angle, so the sun doesn't have to be directly overhead for peak efficiency. In fact, according to Ready, these towers become more efficient when the Sun's light isn't coming directly at them.

Satellites could see a major upgrade as a result of this directional versatility. Since their solar panels would no longer have to face the light directly, the mechanisms wouldn't have to be in place to turn them all day long, like a giant photon-collecting rotisserie. This is a big improvement. The Air Force, aware of the advantage this new system could provide, has been funding some of the research related to this project. Satellites that don't need extra bells and whistles to keep their solar collectors turned to where the Sun shines could be smaller, lighter, and cheaper than their ancestors. ("Smaller, lighter, cheaper" is the carbon nanotube addendum to "better, stronger, faster.") All of the above applies to other Sun-fueled spacecraft as well. Probes, cameras, space stations, commercial spaceliners and space hotels could all benefit from harvesting more of those useful photons emanating from the Sun.

Space isn't the only place where this technology could improve photon collection. Earthly solar panels could get a big boost from the improvement to their efficiency. According to Maria Surma Manka, at Green Options, the new way of structuring solar cells could up their juice output significantly--"These three-dimensional panels produce about 60 times more current than regular solar cells. " Wow. 60 times more current? That could give solar power a much higher usefulness quotient, don't you think? All those panels mushrooming on the roofs of Californians might soon get a whole lot more effective at powering the houses below them. It might even make the mushrooming spread to other territories. I wonder if the nano-enhancements would make solar power have potential even in soggy places like Oregon? (Don't mushrooms like it damp?) Wouldn't that be an incredible feat? A solar-powered Oregon. Only carbon nanotubes could pull that off.

God did a good thing when He invented carbon nanotubes.

Hat tip: Green Options, via Bill Hobbs at Ecotality