New solar-powered devices pull precious resources out of thin air
As you read this, you’re probably surrounded by underutilized resources. The power you’re using to read this post probably came from some centralized source, letting light, moisture and air pollution just go to waste once it reaches your home or office. In an effort to reduce, reuse and recycle these things, three new engineering projects promise to recapture these lost commodities with enough efficiency that we can rely on them to help make the most of the energy and materials in our immediate vicinity.
Filtering air for freshness and fuel
Researchers at the University of Antwerp and the University of Leuven have created a small, solar-powered air purifier that captures fuel for alternative power sources. Pollutants are captured in a specialized membrane built from nanomaterials where they are catalyzed and processed into less harmful compounds. A key byproduct is hydrogen, which can then be collected for use in hydrogen fuel cells. Assuming those fuel cells can replace more polluting fuel sources, this filter should theoretically make itself obsolete if used on a wide enough scale.
Amassing moisture from the atmosphere
A collaboration between MIT and the University of California, Berkeley has yielded another solar-powered filtering device, but instead of pulling pollutants out of the air, it collects water. Unless you’re in an airplane, even some of the driest places on Earth have some small amount of water suspended in the atmosphere. The problem is consolidating that moisture into something you can drink in an efficient manner, and this small device aims to do just that, relying on metal-organic frameworks to capture water vapor on its interior surfaces. The water, which collects in eight-molecule cubes, is then drawn to a condenser, where up 12 ounces of water may be collected in a single hour.
Revamping visible light
If you don’t need cleaner water or air, perhaps you’d just like to recycle some of the electricity you’re already using? A new twist on solar energy collection may soon help us recapture energy we’d otherwise be throwing around our rooms to be lost as ambient heat and light. Dye-sensitized solar cells have been tuned to absorb specific frequencies of the visible light spectrum, helping to increase their efficiency to levels usually attained only by expensive materials like gallium arsenide. You probably won’t be powering your television off of your light bulbs any time soon, but this method of solar collection may allow for lower power devices to include cost-effective solar panels in their design. Devices like passive sensors could be passively powered without the need for external wiring or access to a grid. And as long as you’re turning the lights on anyway, you might as well have a little more to show for it, right?
My second grader said: The solar panels could never power a light bulb to power themselves, right? It’d be like Mars’ moon that gets a little smaller each time it breaks apart and reforms?
Correct. Just like Phobos is thought to loose some of it’s mass each time it breaks apart and reforms, the ambient-light solar panels aren’t going to suddenly become a perpetual energy machine. Right now, they’re achieving 29 percent efficiency in the amount of energy captured, but even if that somehow shot up to 100 percent, the system would still leak some energy in wiring, heat, etc. The nice thing is, since people are committing to this energy usage anyway, it feels like anything that gets captured is “free,” which might make it an easier sell to consumers if manufacturing costs are low enough.