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One Company’s Trash May Be Your Treasure: Salvaging Energy

Illustration for article titled One Company’s Trash May Be Your Treasure: Salvaging Energy

A group of MIT students have found ways to turn shock absorbers into power generators. Salvaging energy wasted by others may be the modern small-business gold rush. Can you cash in?


A college professor of mine often mentioned that the first cars made had small, slim cases mounted to the frame on the driver's side of the car. What were they there for? For buggy whips. One might think that the cases were there in case the car broke down and had to be towed by horses , but they weren't. They were there because every well-made carriage had them, and the horseless carriage was so new that even its makers hadn't fully caught up to the ‘horseless' part of the phrase yet.

Later, designers dispensed with the buggy whip stands, but included fins, domes, heavy frames, big trunks, and back seats large enough for teenagers to get up to no good. Oil was plentiful and cheap, and it allowed people to pile everything they could possibly want onto a car and call it style.


As the oil supply shrank and green concerns grew, a new style, based on sleekness and efficiency came into fashion. Heavy, awkward designs needed to be discarded every bit as much as the buggy whip stands did.

New engineers take it even farther, modifying already-existing parts so that they yield energy. Recently a group of students at MIT turned shock absorbers into power generators.

The way they did this was first by recognizing how shock absorbers worked. Many vehicles have had springs to cushion sharp shocks as they moved. The problem with springs is that they keep jiggling long after the shock is gone. In a car going ten miles per hour, that might be nausea-inducing. In a car going sixty, fast vibration is a danger.

Shock absorbers handle the difficult task of absorbing sharp shocks from the road, but dampening any further vibration. They are cylinders with pistons in them, just like in an engine. Instead of moving though air, the pistons in a shock absorber move through oil. Since liquids don't compress like gasses do, this provides resistance to movement. Small holes are made in the piston to allow the liquid to travel, so when the car hits a bump, the piston will compress and absorb some of the shock from the passengers. When the piston tries to move back, the way a spring would, the oil has to be dragged back through the small holes to allow it to decompress.


It's a little like trying to move through water. If a person falls forward with all their weight, they will move easily into the water. When they try to get back up, though, they won't exert quite as much force, and they will move more slowly. Just like the piston moving through oil, their movement will be minimized.


What the MIT students realized is that shock absorbers are built to slow movement, to dampen force – to dissipate energy. And energy has very high value, right now. By placing a turbine in the absorber, they could harness some of that wasted energy, and use it to power the car's battery.

This breakthrough stands out because of its utility, yes, but also because of its inventors. A prototype was made by a bunch of students. They were MIT students, which meant that they had connections, resources, and expertise readily available to them, but their work is a far cry from the hundreds of millions of dollars spent on building a better fuel cell.


Their work is something that could, in fact, be imitated by just about anyone. More and more people are realizing that if it heats, spits, squirts, expands, compresses, muffles, boosts, flows or rushes, it's a potential source of energy. If ‘it' happens to already be owned by millions of people, then the potential for salvaging that energy for profit, is very, very high. Cashing in, on the new energy revolution might not be as simple as building a better mousetrap, but it might be as simple as hooking that trap up to a turbine.

Via Scientific American.


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Robert Buettner's Orphan series had powered armor that was partially powered by human movement using lightweight pulleys and gears.

One issue with moving vehicles would be to balance any energy gains with the weight gain of all the extra equipment and the resulting decrease in fuel economy.