Nanogenerator harvests power from rolling tyres
Using a phenomenon called the triboelectric effect researchers have
figured out a way to generate electricity from a moving vehicle, increasing the
mileage by up to 10 per cent
A group of University of Wisconsin Madison engineers and a
collaborator from China have developed a nanogenerator that harvests energy
from a car's rolling tyre friction.
An innovative method of reusing energy, the nanogenerator
ultimately could provide automobile manufacturers a new way to squeeze greater
efficiency out of their vehicles.
The researchers reported their development, which is the first of
its kind, in a paper published in the journal Nano Energy.
Xudong Wang, an associate professor of materials science and
engineering and his student Yanchao Mao have been working on this device for
about a year.
The nanogenerator relies on the triboelectric effect to harness
energy from the changing electric potential between the pavement and a
vehicle's wheels. The triboelectric effect is the electric charge that results
from the contact or rubbing together of two dissimilar objects.
Wang says the nanogenerator provides an excellent way to take
advantage of energy that is usually lost due to friction.
“The friction between the tyre and the ground consumes about 10
per cent of a vehicle's fuel,“ he says.
“That energy is wasted. So if we can convert that energy, it could
give us very good improvement in fuel efficiency.“
The nanogenerator relies on an electrode integrated into a segment
of the tyre. When this part of the tyre surface comes into contact with the
ground, the friction between those two surfaces ultimately produces an
electrical charge a type of contact electrification known as the
triboelectric effect. During initial trials, Wang and his colleagues used a toy
car with LED lights to demonstrate the concept. They attached an electrode to
the wheels of the car, and as it rolled across the ground, the LED lights
flashed on and off.
The movement of electrons caused by friction was able to generate
enough energy to power the lights, supporting the idea that energy lost to
friction can actually be collected and reused.
“Regardless of the energy being wasted, we can reclaim it, and
this makes things more efficient,“ Wang says. “I think that's the most exciting
part of this, and is something I'm always looking for: how to save the energy
from consumption.“
The researchers also determined that the amount of energy
harnessed is directly related to the weight of a car, as well as its speed.
Therefore the amount of energy saved can vary depending on the vehicle but
Wang estimates about a 10 per cent increase in the average vehicle's gas
mileage given 50 per cent friction energy conversion efficiency.
“There's big potential with this type of energy,“ Wang says. “I
think the impact could be huge.“
MM1JUL15
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