by Mark Ollig
When traveling during Minnesota’s road construction season, it helps to have good-working shock absorbers installed on our vehicles.
While most of us grit our teeth driving over those bumpier bumps in the road, someone else must have been thinking; “When life gives you lemons, make lemonade.”
Using this analogy; lemons are the road bumps, and lemonade is harvested-energy.
Someone has successfully found a way to convert the “shock momentum” generated from those bumps, into re-usable energy for our vehicle.
To be honest, folks, when I recently came across this discovery, my first thought was of an oscillating dance floor.
Now, hold on . . . I have not slipped off the deep-end; just yet.
My faithful readers will recall the 2008 column about “piezoelectricity” being generated using the energy of a moving dance floor.
In this column, I wrote: “Some night clubs across the big pond in Europe have special dance floors built with piezoelectrics which absorb and convert the kinetic energy from dancing footsteps into electricity. This energy is used to help power the lighting above and on the dance floor.”
In the Netherlands, a night club called Club Watt features an interactive piezoelectric sustainable dance floor.
This dance floor is able to generate almost 60 percent of the building’s electricity needs.
An average of 5 to 10 watts of power is generated per person while dancing on this specially-built floor.
Yes, each person is essentially a battery (queue “The Matrix” sci-fi movie scene showing thousands of vertically-stacked, interconnected pods; each containing one immobile human being functioning as a battery source to power the Matrix).
The nightclub’s dance floor is fitted with a built-in “bouncing floor” (stay with me on this) which is made up of heavy springs and rectangular cylinders called “power generating blocks” installed in-between the springs.
The blocks are made with crystals; the dancers on this floor will cause the blocks to produce a small electrical current when they are compressed – this is the piezoelectricity process in action.
Getting back to those bumps in the road – what if your car could capture, and make use of the energy generated from the action each shock absorber makes while traveling over those bumps?
Lei Zuo, an associate professor at Virginia Tech, has successfully demonstrated “energy-harvesting” via a car’s suspension system using specially-modified shock absorbers.
Zuo has many engineering degrees, including a Ph.D. in mechanical engineering from Massachusetts Institute of Technology.
He described the three recoverable energy sources a vehicle creates while driving: the heat dissipated from the engine, kinetic energy from deceleration or braking, and vibrational energy, which is reduced by using shock absorbers.
Zuo has developed a shock absorber which will harvest energy.
He explained how an energy-harvesting shock absorber takes the vertical, piston-like vibrations of the vehicle’s suspension system, and transforms this into the rotational action needed to turn a generator.
This generator then sends electrical power to the vehicle’s battery, or any of its other electrical devices.
Thus, this new source of electrical energy decreases the electrical draw from the vehicle’s alternator.
I noted the modified shock absorber’s generator will still rotate for a while; even after the vibration stops, allowing a bit more energy to be generated.
Zuo believes 100 to 400 watts of energy could be provided by a vehicle’s shock absorbers traveling over normal roads, and even more on bumpier ones.
Zuo and students in his class tested their specially-built, energy-harvesting shock absorber on the school’s campus roads.
Their test results found they could generate 60 percent of the available energy.
The class’s energy-harvesting shock absorber was built using off-the-shelf parts.
Future improvements include installing a microprocessor for detecting and adjusting the vehicle’s suspension settings for various road conditions encountered while traveling.
Zuo hopes to collect the maximum amount of a vehicle’s harvestable energy, while providing a smooth driving experience for its occupants.
Fuel efficiency, if increased by 5 percent per vehicle on a nationwide basis, could result in an annual $19 billion in fuel cost savings.
Virginia Tech’s Center for Energy Harvesting Materials and Systems web page can be found here: http://tinyurl.com/bitsCEHMS.
Bits & Bytes' "Dance the night away and create some electricity" Dec. 8, 2008 column, is archived at http://tinyurl.com/12082008.
