It's No
Small Matter To Lehigh
Scientists
A silicon chip that produces hydrogen to operate a laptop
computer? Scientists at Lehigh University are developing a
tiny generating plant, housed on a silicon chip, that they
believe can produce enough hydrogen to run
power-consuming portable devices.
The amount of hydrogen produced was small, but it was
enough to demonstrate that the Lehigh project is feasible.
Given time the Lehigh group believes they will develop a
working generating plant, housed on a silicon chip, that
produces sufficient quantities of hydrogen to run different
types of power consuming portable devices.
"About 10 years ago people starting thinking: 'can we take
the same fabrication methods for silicon chips and instead
of using them for electronics, use them for something
else?'" says Mayuresh Kothare, assistant professor of
chemical engineering.
Instead of a processing device for electrons, chips would
become miniature chemical reactors or power plants.
Kothare says that in one experiment a silicon chip was
turned into a tiny steam engine. The channels normally used
to transmit electrical current were used to carry steam. They
could just as easily have been used to carry various reagents
to fuel miniature reactors or generating plants housed in the
chip's processing areas. In an experiment at the Sandia
National Laboratory in New Mexico scientists created a
miniature geared engine on a chip.
"At Lehigh our chip-based micro-chemical plant will take a
reagent, such as methanol, or a hydrocarbon, like diesel or
gasoline, and carry it to a tiny reactor to produce hydrogen,"
Kothare says. "We have already produced hydrogen and
have been able to get the reagents into the reactor to carry
out the necessary reaction."
The hydrogen will be collected in a miniature fuel cell that
can power an electronic device. A fuel cell creates power
through the electrochemical reaction of hydrogen and
oxygen.
The chip is the same size as an ordinary electronic chip,
approximately three centimeters by three centimeters. The
micro-plant would be fueled by small cartridges of
methanol, or other hydrocarbons, that are fed to the
"reformer" by micro-capillaries or miniature fuel lines. The
reformer would be heated by electricity and the reaction
would produce hydrogen which would be transmitted to the
fuel cell via another network of micro-capillaries.
While one chip could not produce enough power to operate
a laptop, Kothare says that by wrapping scores or hundreds
of the tiny micro-plants together -- called "numbering up"--
enough power could be produced to operate all kinds of
electronic devices. A recent experiment in Germany
demonstrated that a hydrogen micro-fuel cell powered a
laptop computer for up to ten hours whereas the operating
time of an ordinary rechargeable laptop battery is generally
about two hours.
Kothare also notes that by using a chip power plant one
would not need to stop to recharge a battery. Just insert a
new fuel source of methanol, diesel or gasoline to the chip
plant and the power continues.
Currently, one of the hurdles in creating a working plant is
getting the reagents into the micro-capillaries. "Think of
piping in your own house," Kothare says. "You can buy
standard fittings but there are no standard fittings for the
chip plant and there are no standardized pipes. To get the
reagents in is a whole world of its own. You don't know
how much will leak or vaporize or if it is sealed tightly."
While Kothare and his colleagues are working on a
chip-based power plant, he notes that there could be
unlimited uses for devices developed from microchips. One
use could be the implantation of a processing chip inside
the body to conduct all sorts of medical functions. A tiny
chip-analyzer could take in minuscule amounts of blood,
and analyze it for such things as sugar or insulin levels.
Blood tests could be done instantly without need of sending
the results to a lab.
Funding for Kothare's projects comes from the National
Science Foundation (NSF) and the Sandia National
Laboratory in New Mexico. Support also comes from the
Pittsburgh Digital Greenhouse, a consortium of electronics
companies in Pittsburgh.
Note: This story has been adapted from a news release issued by
Lehigh University for journalists and other members of the public.
If you wish to quote from any part of this story, please credit
Lehigh University as the original source. You may also wish to
include the following link in any citation:
http://www.sciencedaily.com/releases/2001/08/010824081233.htm
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