Capturing and utilizing waste energy has long been an avenue of
scientific study, but has become even more so recently with fuel and
other energy costs rising steadily. By capturing waste energy, most
likely to be heat or fluid dynamic (air and water movement), direct
energy requirements for everything from home electronics to
automobile and other transportation craft may be reduced, thus
reducing the cost in petroleum or bio-based fuels all around.
DailyTech has focused on thermoelectric compounds in the
past, covering work like Mildred S. Dresselhaus, a professor with
MIT’s work
with composite materials to increase heat to energy efficiency
using molecular structures. Thermoelectrics create electricity when
heat is applied to them, or create opposed hot and cold surfaces when
electricity is applied.
Kinetic waste energy, however, must be captured by more mechanical
means. This could be as simple as attaching a wind turbine to the
roof of a car. Of course, no one wants to be seen driving around in
such an automobile, and there are other factors involved that would
decrease the overall efficiency of such a system.
A team from the City College of New York has come up with an
interesting compromise between aesthetics, aerodynamics and power
generation. They have presented their device and research today at
the 62nd Annual Meeting of the American Physical Society’s
Division of Fluid Dynamics, titled “Harvesting
energy in the wake of a circular cylinder using piezoelectric
materials.”
The device in question measures about one half inch by one inch.
It uses a piezoelectric cantilever system to generate electricity
from the turbulence created by air passing over a cylinder in motion.
This cylinder could be a car or an airplane. To attain a maximum
power output, the vibration of the cantilevers in the air stream is
tuned to the device’s resonant frequency.
The units could be placed en masse on an airplane fuselage or
built into the tail areas of motor vehicles. They would then generate
additional energy for the vehicles’ systems. This power would
definitely not be enough to replace the normal engine driven power
generation system, but it could lighten the load from the main
battery for things like display panels or charging stations for
phones and laptops.
Combined with thermoelectric devices that capture waste heat
energy from combustion engines, these kinetic energy traps could
provide a possible significant boost to a vehicle's electric systems.
Though hybrids could also benefit from the technology, it stands to
reason that fully battery-powered vehicles wouldn't see a reasonable
gain from the same combination. The piezoelectric devices alone,
though, could be a great addition.