Rama Venkatasubramanian's research into postage-stamp-sized cooling/heating devices proves that a phase change isn't always the best way to move heat.
Present position: Research Director of the Center for Thermoelectrics Research at the Research Triangle Institute, North Carolina
Degrees: B.S.E.E., Indian Institute of Technology, Madras, India, and Ph.D. in Electrical Engineering, Rensselaer Polytechnic Institute, Troy, New York
Area of research: Development of nanometer-scale thermoelectric devices that convert electricity into cooling or heating or electric power from heat.
How you describe what you do at cocktail parties: I tell people that I want to cool objects that I cannot see!
What is a thermoelectric? It's a solid-state device that uses dc current to transfer heat or uses heat to produce power. Nanometer-scale devices consist of up to 1,000 layers of thin film materials that operate with high efficiency, and are extremely fast and ultra-compact.
Biggest breakthrough: We have been able to engineer these nanostructures in such a way that heat flow is prevented but the electrical flow is enhanced.
Isn't a phase change a more efficient way to move heat? Sure, on a large scale. But as you start reducing the size of a mechanical system, the efficiency falls. Another advantage is speed—our devices operate in microseconds range. It will be nearly impossible for mechanical systems to achieve that kind of performance, not to mention the small size. With further improvements, we could compete in efficiency as well.
First practical application? Spot cooling of electronic components.
Why nano-scale thermoelectrics? When I looked at this field in 1992, I discovered that there was very little enthusiasm in the industry to push the state-of-the-art. I considered that a challenge and proposed these nano-scale structures to overcome some unescapable realities of heat and electricity flow in conventional solid-state materials.
Contact Rama at