There is really not a lot new
here. It is still a modification of the
rankin cycle to use the energy to produce cooling power.
The real problem has been to get
anyone to go the extra mile and adopt such systems at all. It is generally impossible to fit them in on
the original build, leaving the operator to attempt it as a retrofit and all
the inefficiency that comes with that.
The reality of the bidding
process makes it hard to fit in heat scavenging into the original package or to
finance it. And in fairness, the incremental
improvement is difficult to justify against the actual scale of any operation
and surely awaits superior energy storage anyway..
PROTOTYPE DEMONSTRATES SUCCESS OF ADVANCED NEW ENERGY TECHNOLOGY
6-10-11
The study this story is based on is available in ScholarsArchive@OSU: http://bit.ly/ljOJZh
CORVALLIS, Ore. – With the completion of a
successful prototype, engineers at Oregon State University have made a
major step toward addressing one of the leading problems in energy use around
the world today – the waste of half or more of the energy produced by cars,
factories and power plants.
New technology is being developed at OSU to capture and use the
low-to-medium grade waste heat that’s now going out the exhaust pipe of
millions of automobiles, diesel generators, or being wasted by factories and
electrical utilities.
The potential cost savings, improved energy efficiency and broad
application of such technology is enormous, experts say. The new systems now
being perfected at OSU should be able to use much of that waste heat either in
cooling or the production of electricity.
A prototype device has been finished to demonstrate the efficacy of
this technology, and the findings just
published in Applied Thermal Engineering, a professional journal.
“This could become a very important new energy source and way to
improve energy efficiency,” said Hailei
Wang, a research associate in the School of Mechanical ,
Industrial and Manufacturing Engineering at OSU. “The prototype shows that
these systems work as well as we expected they would.”
More than half of the heat generated by industrial activities is now
wasted, Wang said, and even very advanced electrical power plants only convert
about 40 percent of the energy produced into electricity. The internal
combustion engines of automobiles are even worse – they generally operate
around 25-40 percent conversion efficiency. The very function of an automobile
radiator is to dissipate wasted heat.
Various approaches have been attempted, and are sometimes used, to
capture and use at least some of that waste heat to produce cooling. The new
system being developed at OSU may do that as, or more efficiently than past
approaches, be more portable, and also have one major advantage – the ability
to also produce electricity.
It’s called a “thermally activated cooling system” that gains much
of its efficiency by using extraordinarily small microchannels which help to
better meet the performance, size and weight challenges. It effectively
combines a vapor compression cycle with an “organic Rankine cycle,” an existing
energy conversion technology.
The new prototype completed at OSU succeeded in turning 80 percent of
every kilowatt of waste heat into a kilowatt of cooling capability. Researchers
say the conversion efficiency wouldn’t be nearly as high if the goal is to
produce electricity – about 15-20 percent – but it’s still much better than the
current approach, which is to waste the energy potential of all of the heat.
“This technology would be especially useful if there’s a need to have
cooling systems where heat is being wasted,” Wang said. “That’s one reason the
research has been supported by the Department of Defense, because they see it
being used to provide needed air conditioning for electronics and other
purposes when they are using generators in the field.”
However, the OSU scientists said that may be just the beginning.
Factories often produce enormous amounts of wasted heat in their operations.
The systems could also be incorporated into alternative energy technologies
such as solar or geothermal, scientists say, in addition to fossil fuel use.
Conceptually, it should also be possible for such systems to be used in
hybrid automotive technology, taking waste heat from the gasoline engine and
using it not only for air conditioning but also to help recharge the battery
that powers the vehicle, Wang said.
Continued research will be needed to perfect the technology and adapt
it to different uses, the scientists said.
The work takes advantage of OSU’s advanced programs in microchannel
technology, a key focus of the Microproducts
Breakthrough Institute operated by OSU and the Pacific
Northwest National Laboratory. This study was co-authored by Rich
Peterson, an OSU professor of mechanical engineering, expert in thermal
sciences and energy systems, and associate director of the Microproducts
Breakthrough Institute.
“There continues to be significant potential for reducing energy
consumption and greenhouse gas emission by improving overall energy efficiency
for various energy systems,” the scientists said in their study. “One route
toward satisfying both paths is to develop technology able to recover waste
heat that would be otherwise rejected to the atmosphere without usage.”
About the OSU College of Engineering: The OSU College
of Engineering is among the nation’s largest and most productive engineering
programs. In the past six years, the College has more than doubled its research
expenditures to $27.5 million by emphasizing highly collaborative research that
solves global problems, spins out new companies, and produces opportunity for
students through hands-on learning.
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