Mechanical and Civil Engineering Seminar

Mechanical and Civil Engineering Seminar Series

Title: A brief history of development of elastocaloric cooling

Abstract: In early 2000s, we carried out a series of combinatorial materials screening studies to discover NiTi-based shape memory alloys (SMAs) with minimal hysteresis guided by the non-linear theory of martensite [1]. The original application we had in mind for such SMAs was long fatigue-life peripheral vascular stents. A follow-on study has then led to new quaternary alloys with even better functional-fatigue behavior. It had long been known that certain elastic materials such as natural rubber and some SMAs exhibit the elastocaloric effect, where mechanical stress loading results in adiabatic temperature changes. In 2010, we realized that fatigue-resistant SMAs with large latent heat would be effective as solid refrigerants for an environmentally friendly cooling technology. We have then gone on to demonstrate elastocaloric cooling with large temperature lifts in superelastic SMAs, which can rival the best magnetocaloric materials in cooling efficiency [2]. In 2012, a U.S. Department of Energy report named thermoelastic (elastocaloric) cooling the most promising alternative cooling technology (out of 17 possible options). We have recently demonstrated a four-bundle multi-mode elastocaloric system which produced 260 W in delivered cooling [3]. I will try to discuss key lessons we learned (or failed to learn) from various combinatorial high-throughput experiments as well as development of elastocaloric prototypes. This work was carried out in close collaboration with Jun Cui, Suxin Qian, Reinhard Radermacher, Yunho Hwang, and R. D. James. Our work has been funded by NIH, DOE, NSF, ONR, and ARO over the years.

[1] Cui et al., Nature Materials 5, 286 (2006).
[2] Takeuchi and Sandeman, Physics Today 68, 48 (2015).
[3] Qian et al., Science 380, 722 (2023).

Bio: Ichiro Takeuchi is the interim chair and professor of materials science and engineering and affiliate professor of physics at the University of Maryland. Takeuchi received his B.S. in physics from Caltech. He then spent 4 years as a staff member in the Josephson electronics group at NEC Labs in Japan. Takeuchi received his Ph.D. in physics from the University of Maryland. Prior to joining the Maryland faculty, he was a postdoctoral associate at Lawrence Berkeley National Laboratory, where he helped pioneer the combinatorial materials science methodology. Takeuchi's research interests include high-throughput discovery of materials, machine learning for materials science, elastocaloric cooling, and superconducting devices. Since 2009, Takeuchi has also served as the CTO of Maryland Energy & Sensor Technologies, a start-up dedicated to development of elastocaloric cooling systems. Takeuchi is a fellow of the American Physical Society, Materials Research Society, and the Japan Society of Applied Physics.

NOTE: At this time, in-person Mechanical and Civil Engineering Lectures are open to all Caltech students/staff/faculty/visitors.