Oct 16 2009
G. Jeffrey Snyder, faculty associate at the California Institute of Technology, will give a talk Wednesday (Oct. 21) from 11 a.m. to noon in Room 204 of the Engineering Physics Building on campus.
Snyder’s talk, “Nanostructured Thermoelectric Materials for Power Generation and Cooling,” is part of the Nano/Micro Seminar Series sponsored by the Department of Electrical and Computer Engineering.
Abstract
A thermoelectric generator directly converts heat into electricity with no moving parts. The long-term reliability of these systems has enabled the unattended use of thermoelectric generators in many deep space probes exploring the solar system and beyond. On earth, thermoelectrics could provide a substantial amount of electrical power from residential cogeneration and waste heat recovery from sources such as automotive exhaust. When connected to an external power supply, a thermoelectric generator becomes a solid-state (Peltier) refrigerator, cooling one end and heating the other. Such systems can be used to cool a spot instead of traditional environment cooling thereby greatly improving overall efficiency. Thus far, the use of thermoelectric generators has been limited to niche applications by the low efficiency of the thermoelectric materials.
Several new classes of compounds from oxides and intermetallics to composite materials have been discovered which show enticingly high efficiencies. A general feature of these new materials is that they all involve complex nanostructured materials. The rationale behind these successes can typically be generalized into (a) quantum confinement of electrons to enhance thermopower (Seebeck coefficient), (b) low lattice thermal conductivity through structural complexity on various length scales, and/or (c) substructure approaches which separates the ‘electron-crystal’ from the ‘phonon–glass’. By reviewing recent advances in the field, these strategies are evaluated to help guide the development of revolutionary thermoelectric materials.
Biography
G. Jeffrey Snyder is a faculty associate at the California Institute of Technology (Caltech) in Pasadena, Calif. His interest is focused on thermoelectric engineering and advanced materials development such as complex Zintl phase and nanostructured bulk thermoelectric materials. He obtained his B.S. degree in physics, chemistry and mathematics at Cornell University (1991) and his Ph.D. in applied physics from Stanford University (1997) where he was a Hertz Fellow. He was a senior member of the technical staff in the thermoelectrics group at NASA’s Jet Propulsion Laboratory for nine years (1997-2006) where he focused on thermoelectric materials and devices. Snyder has published more than 100 articles, book chapters and a number of patents.