Fundamental Problems in Transport and Storage of Heat in Advanced and Emerging Technologies

Sanjiv Sinha, PhD
Professor
University of Illinois at Urbana-Champaign

Abstract: We examine two engineering problems posed by advanced and emerging technologies respectively that involve, in one case the transport of heat, and in the second case its storage. Scaling at the extreme limits of Moore’s law leads us to three-dimensional transistors with nanoscale heat dissipation regions that are nevertheless larger than the feature size of the transistor. With growing interest in understanding transient thermal transport in these complicated geometries, we discuss recent breakthroughs in GPUaccelerated multi-scale electrothermal simulations of deeply scaled FinFETs. Our ability to solve the transient phonon Boltzmann transport equation for spectral phonons in three spatial dimensions enables new insights into the transient heating and cooling of transistor bodies. Second, we discuss experimental work on solving the long-standing problems with cycling loss in thermal energy storage using phase change materials based on hydrated salts. As abundant and inexpensive materials for heat storage, hydrated salts suffer from peritectic phase transitions (incongruent melting) and supercooling. We report successful solutions to these problems for Glauber’s salt and sodium acetate trihydrate with negligible loss in storage over hundred cycles. Both problems showcase the continued importance of engineering thermal transport in industries that are critical to modern civilization.

Biography: Sanjiv Sinha is Professor and Associate Head for Undergraduate Programs in the Mechanical Science and Engineering Department at the University of Illinois Urbana-Champaign. His research interests are in fundamental thermal and electrothermal transport, nanoscale thermometry and thermal energy systems. Sinha received the B.Tech degree from IIT-Delhi, and the M.S. and Ph.D. degrees from Stanford University, all in Mechanical Engineering. He worked as a Research Engineer at Intel Corporation, Intel Research – Berkeley and at UC, Berkeley, prior to joining UIUC. Sinha has received the NSF-CAREER and the DARPA-YFA awards in his academic career. He has twice been awarded for Excellence in Advising by the UIUC College of Engineering and has been on the list of Excellent Teachers across the University of Illinois campus five times. He is the recipient of the 2021 Stanley H. Pierce Award from the Grainger College of Engineering at Illinois for promoting interactions between students and faculty