Nanotechnology turns heat into electricity

Kevin Bullis of Technology Review reminds us of something we should all remember from thermo class:

Inside fossil-fuel and nuclear-power plants, as well as in cars and trucks, the lion’s share of energy in fuel is wasted as heat rather than converted into electricity or mechanical power. But the search for a practical material that can convert at least some of this waste heat into electricity has been long and frustrating.

UC Berkeley nanotechnology researchers Rachel Segalman, Arun Majumdar, and team to the rescue:

The researchers trapped a few molecules between a sheet of gold and the ultrafine gold tip of a scanning tunneling microscope, which is so sharp it can end in a single atom. They heated up the gold surface and measured, via the microscope tip, the voltage that was created…The results confirmed that the organic molecules could indeed be used to generate electricity from heat…The research is only the first step, the researchers say, and, because much work remains, applications will be many years away.

If all goes well, though, so-called thermoelectric devices based on the molecules could prove to be an important source of power–and a way to reduce greenhouse-gas emissions by making far more efficient use of fossil fuel. “Ninety percent of the world’s electricity is generated by thermal-mechanical means,” says Arun Majumdar, professor of mechanical engineering at UC Berkeley and another researcher on the project. “And a lot of the heat is wasted. One and a half times the power that is generated is actually wasted.”

For an overview of nanotech by Arun Majumdar, published in 2001 but still worth reading, see “Not Without Engineering” in Mechanical Engineering magazine, mentioned here on Nanodot earlier. About flagellar motors, he writes:

Biologists have investigated these motors. If, however, one looks at them from the engineer’s viewpoint, one could envision isolating the motors to propel nanoscale robots…

This group’s current results encourage us in our belief that gaining control of matter “all the way down” to the molecular level can make a huge, positive difference to society. (Credit: Billy Harvey) —Christine

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