Engineer's energy research may cut costs, increase efficiency Published Sept. 9, 2008 By Molly Lachance Air Force Office of Scientific Research ARLINGTON, Va. (AFPN) -- An Air Force Office of Scientific Research-funded mechanical engineer here has developed an inexpensive, efficient material that will enable electronic devices to quietly and motionlessly self-regulate temperature and convert excess heat into a power source. This new development could impact the energy sector, as cost and efficiency have often precluded the wide use of conventional thermoelectric materials in converting thermal energy into electricity. Broader military and commercial applications, ranging from refrigeration to self-powered sensors to more fuel-efficient cars, may be possible. Dr. Ronggui Yang's method, developed with his colleagues at the University of Colorado at Boulder, involves fusing nanoparticles and nanowires to create a composite material. Use of nanoscale components helps to slow heat flow, which improves the material's ability to convert thermal energy into electricity. The resulting nanocomposite material not only performs well in tests, but also can be mass-produced at a low cost. An important aspect of Dr. Yang's success was his decision to collaborate with experts in other disciplines and take advantage of advances in areas such as computation, physics and materials science. "We are using quantum mechanics simulation to understand how electrons behave in nanostructures and using topology optimization coupled with statistical mechanics simulation to design thermal nanostructures," he said. Dr. Yang has also devoted considerable effort to understanding the fundamentals of thermoelectric materials, which allows him to explain his method in relatively simple terms and react quickly to new design and structural concerns. "To apply these nanocomposites in components and systems, we have to understand application constraints," he said. "For example, structure integration could be critical when harvesting energy in Air Force environments with large temperature gradients such as aerial vehicles during operation." Air Force Office of Scientific Research officials are particularly interested in integrating this new generation of thermal materials into microscale unmanned aerial vehicles. They fund this aspect of Dr. Yang's work through a Multidisciplinary University Research Initiative grant for the integration of energy harvesting and storage capabilities into load-bearing structures. In addition to the MURI grant, Air Force Office of Scientific Research officials also support Dr. Yang through a Discovery Challenge Thrusts program on thermal transport phenomena and scaling laws, and officials from the National Science Foundation provide funding for his design-centered approach to nanoengineering. This breakthrough research has led Technology Review magazine to name Dr. Yang in the 2008 TR35 list. The TR35 is an annual list of 35 outstanding men and women under the age of 35 who exemplify the spirit of innovation in business and technology. Comment on this story (comments may be published on Air Force Link) View the comments/letters page