Guest Speaker: Prof. YAO Shuhuai
Department of Mechanical and Aerospace Engineering
The Hong Kong University of Science and Technology
Prof. Shuhuai YAO is a Professor in the Department of Mechanical and Aerospace Engineering and a joint faculty member in the Department of Chemical and Biological Engineering at the Hong Kong University of Science and Technology. She obtained her B.S. degree in Engineering Mechanics from Tsinghua University and both her M.S. and Ph.D. degrees in Mechanical Engineering from Stanford University. Following her doctoral studies, she completed postdoctoral training at Lawrence Livermore National Laboratory. Prof Yao’s research focuses on the exploration of micro-/nano-scale fluid dynamics and heat transfer phenomena, with a particular interest in integrating theory and experiments to develop innovative technologies for instrumentation. Prof. Yao has published in top journals such as Naure, Nature Energy, Nature Physics, Nature Communications, Physical Review Letters, etc, and holds ten granted patents and has filed more than forty patent applications, three of which have been licensed to HKUST spin-off startups. In addition, Prof. Yao co-founded two startup companies based on her patented microfluidic technologies developed at HKUST.
Abstract
A significant portion of global carbon emissions comes from refrigerators, air-conditioners, and heat pumps that rely on vapor-compression technology. Conventional hydrofluorocarbon (HFC) refrigerants used in these systems are potent greenhouse gases; direct refrigerant leakage alone accounts for roughly 37% of total air-conditioning-related carbon emissions. Solid-state elastocaloric refrigeration offers a compelling alternative. By exploiting the latent heat associated with phase transformations in shape memory alloys (SMAs), elastocaloric systems are greenhouse-gas–free, fully recyclable, and energy-efficient. While prior research has emphasized SMA thermomechanics and material properties, comparatively little attention has been paid to system-level heat transfer. To address this gap, we developed modeling and simulation tools to optimize design parameters and quantify heat losses. Guided by these models, we engineered multiple generations of elastocaloric cooling devices. Our compression-based systems, featuring a microchannel structural design and cascade multicell architecture, enhance the system heat transfer and lifetime. We have demonstrated kilowatt scale cooling power and sub-zero refrigeration. Our bending-loaded systems, using a rolling-shuttle actuation of thin wires, achieve coefficient of performance (COP) >5 for direct air conditioning and dehumidification. Our work represents a significant advancement toward eco-friendly, scalable elastocaloric cooling technologies for next-generation HVAC.
