about half the energy produced by cars, factories, and power plants is wasted as
heat that escapes into the atmosphere.
Engineers from Oregon State University have made a major step towards
addressing one of the most common wastes of energy today by recapturing some of
the heat generated by a motor and using that energy to produce power. The
engineers have successfully completed
a prototype machine that can be attached to the exhaust pipe of
automobiles, diesel generators, factory, and utility machinery that produces
waste heat. The prototype system is being perfected at the university right
"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
The researcher says that over half the heat generated by industrial activities
is currently wasted. Even the most efficient plants according to Wang only
convert about 40% of the energy produced into electricity. Combustion engines
inside vehicles are even less efficient converting only 25-40% of the energy
The system that the team in Oregon has produced is called the thermally
activated cooling system. The system is able to combine a vapor compression
cycle with an organic Rankine cycle, which is an existing conversion
technology. Using the prototype, the team at the university was able to turn 80%
of every kilowatt of waste heat into a kilowatt of cooling capability. However,
the efficiency wouldn't be as high at about 15-20% efficiency if the goal was
to produce electricity.
"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."
The team is looking at the system to power air conditioning systems in a hybrid
auto and recharge the batteries at the same time. German scientists have
previously developed a system that is able to generate
power from wasted heat that can be turned into electricity.
Researchers at the ORNL have also worked on a system that captures
the water that is in the exhaust from diesel engines to provide
drinking water for soldiers in the field.