The research of Zlatan Aksamija, an Assistant Professor of Electrical and Computer Engineering at UMass Amherst, and his grad student Adithya Kommini was highlighted in the September 19 “news” section of the Massachusetts Green High Performance Computing Center (MGHPCC) website. The two researchers use computers at the MGHPCC to carry out nanomolecular materials modeling experiments exploring the thermoelectric behavior of materials for use in energy applications. See entire article
As the MGHPCC article, written by Helen Hill, explains, “Efficient thermoelectric devices are key to our ability to harvest thermal energy from many sources, among them waste heat lost in traditional electricity production and through automobile exhaust. Two-thirds of the energy generated by conventional power stations is lost as waste heat to cooling towers. A similar percentage of the energy locked up in the fuel you put in your car is lost the same way from the exhaust pipe. But what if that wasted heat could be mopped up and converted into usable electricity?”
Hill observes that the way scientists are solving this problem is to use a material that can conduct electricity using positively charged particles rather than electrons. Aksamija and Kommini are trying to do just this by introducing potential barriers that only allow charged particles with high energy to move from one end to the other. The shape and size of the potential barriers control the amount of charge particle filtering, thus improving the voltage created by the thermoelectric effect without affecting the thermal conductivity.
Hill’s article says that charge particles encountering potential barriers experience quantum effects that become predominant especially at the nanomolecular scale. Using computer models to explore the character of such nanomolecular systems, Kommini and Aksamija hope that, along with the structure of the potential barrier, a better understanding of the quantum effects they cause can help to improve the overall thermoelectric efficiency of the material.
“Nanoengineered silicon wires and nanocomposites have been shown experimentally to have tremendous potential as future thermoelectrics due to their high electrical and low thermal conductivity which, combined, yields a very high energy conversion efficiency,” says Aksamija. “Nonetheless, their usefulness hinges on our ability to simulate and predict which combination of material, geometry, and process is most efficient in energy harvesting applications.”
Aksamija is interested in semiconductor nanostructures for energy applications, thermoelectric energy conversion, dissipation in nanoscale devices, electro-thermal simulation, nanoscale heat transfer, thermal devices, and computational nanoscience. Aksamija is PI for the NanoEnergy & Thermophysics (NET) Lab. Kommini is a Ph.D. student working in the NET Lab. He presented the poster HPC_day_17 at HPC Day 2017.
The MGHPCC provides state of the art infrastructure for computationally intensive research that is indispensable in the increasingly sensor and data-rich environments of modern science and engineering. Computers at the MGHPCC run millions of virtual experiments every month, supporting thousands of researchers in Massachusetts and around the world. (September 2017)