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Thin,
Light, Flexible Heaters Save Time and Energy
Industrial Productivity
Originating Technology/NASA Contribution
Ice accumulation is a serious safety hazard for aircraft.
The presence of ice on airplane surfaces prevents the even
flow of air, which increases drag and reduces lift. Ice on
wings is especially dangerous during takeoff, when a sheet
of ice the thickness of a compact disc can reduce lift by
25 percent or more. Ice accumulated on the tail of an aircraft
(a spot often out of the pilot’s sight) can throw off a plane’s
balance and force the craft to pitch downward, a phenomenon
known as a tail stall.
The Icing Branch at NASA’s Glenn Research Center uses the
Center’s Icing Research Tunnel (IRT) and Icing Research Aircraft,
a DeHavilland Twin Otter twin-engine turboprop aircraft,
to research methods for evaluating
and simulating the growth of ice on aircraft, the effects
that ice may have on aircraft in flight, and the development
and effectiveness of various ice protection and detection
systems.
Partnership
EGC Enterprises Inc.
(EGC), of Chardon, Ohio, used the IRT
to develop thermoelectric thin-film heater technology to
address in-flight icing on aircraft wings. Working with researchers
at Glenn and the original equipment manufacturers of aircraft
parts, the company tested various thin, flexible, durable,
lightweight, and efficient heaters and developed a thin-film
heater technology that they discovered can be used in many
applications, in addition to being an effective deicer
for aircraft.
Product Outcome
The result of this research was the development of a new
thermoelectric heater the company has dubbed the Q•Foil Rapid
Response Thin-Film Heater, or Q•Foil, for short. The product
meets all criteria for in-flight use and promises great advances
in thin-film, rapid response heater technology for a broad
range of industrial applications. Primary advantages include
time savings, increased efficiency, and improved temperature
uniformity.
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Developed
in conjunction with NASA for in-flight aircraft deicing,
Q•Foil heaters are now available for a broad range
of applications from as small as a single square
inch to as large as several square feet, and provide
extremely rapid thermal response and even heating
for a wide array of temperature ranges. |
EGC makes the heaters out of thin layers of varying materials
that are bonded to form heater laminates. The inner layer,
made of a flexible graphite foil (marketed separately by
EGC as ThermaFoil), is electro-thermally conductive and typically
laminated between a heat-conducting outer layer, and a protective
insulating layer. The inner layer provides full electrical
conductivity, eliminating the need for wire elements, metal
etchings or heat-conductive fibers. In addition to being
readily available and relatively inexpensive, the graphite
foil is energy efficient.
Because Q•Foil conducts heat well and can cover a large area,
little energy is needed for it to raise the surface temperature
to the necessary degree, and it is capable of heat increases
as rapid as 100 °F per second if needed, which can translate
into savings in time or energy. Designers can configure it
to heat an item more quickly or to heat an item to the same
temperature as other heaters would, while expending less
energy.
Not only does Q•Foil work quickly and efficiently, it is also precise, controllable
to within 3 °F. If it is being used for an application that requires different
temperature zones, Q•Foil can also be configured to accommodate this within the
same heating coil.
While the product is available in a variety of sizes, ranging from 1 square inch
to 100-foot lengths, the company notes that it is most efficient over large spaces,
as this allows the user to get the most advantage of its unique cost- and energy-saving
properties. Thin-film flexibility allows it to be mounted to a variety of objects,
and it maintains flexibility through a full range of temperatures. The company
has services to assist customers with determining the right dimensions and designs
they will require for a specific job.
In addition to wing deicing, EGC has begun looking at the material’s usefulness
for applications including cooking griddles, small cabinet heaters, and several
laboratory uses.
Q•Foil™ is a trademark, and ThermaFoil® is a registered trademark of EGC Enterprises
Inc.
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