Most Tucsonans would agree that Tucson has more than enough heat to go around, but few think our excess heat is good for anything.
Since the mid-19th century, scientists and engineers have understood that heat is a form of energy that can be converted into other, more useful, forms of energy. Unfortunately, engines that do so typically burn stuff, which leads to waste heat.
At the University of Arizona, my students, colleagues and I are developing technology to turn waste heat from sources such as roof-top solar panels and automobile and factory exhausts into electrical energy.
By taking advantage of the temperature difference from one side to the other of a "thermoelectric" material, thermoelectric engines cleanly convert heat into electrical energy. Unfortunately, aside from some small-scale niche applications, until now thermoelectrics were just too inefficient and too expensive.
My research team is circumventing longstanding roadblocks toward greater efficiency by using the quantum properties of electrons to build more efficient thermoelectrics.
We are forming more efficient thermoelectric junctions by binding particular organic molecules to common metal surfaces.
Moreover, we anticipate such molecular junctions will be far cheaper to produce. They can be formed by simply "painting" a molecular thermoelectric onto a metal surface such as an automotive exhaust header or factory exhaust stack.
We are working toward putting all of Tucson's excess summer heat to work.
About the scientist
Charles Stafford is a University of Arizona professor of physics and co-director of the UA's interdisciplinary Chemical Physics Program. His research focuses on harnessing energy and electricity at the quantum level. He has received two U.S. patents for his inventions based on nanotechnology. In 2000, he received the ABB Prize of the Swiss Physical Society for his work on metal nanowires.
• Capturing waste heat: www.azpbs.org/horizon/detailvid.php?id=2640
• Charles Stafford's webpage: http://www.physics.arizona.edu/~stafford/
• Justin Bergfield's webpage: faculty.wcas.northwestern.edu/justin-bergfield/media.html