Zhengmao Lu (EPFL, Switzerland)

Leverage Liquid-Vapor Phase Change for High-Performance Sustainable Cooling

Liquid-vapor phase change phenomena plays a critical role in global energy and water systems. However, the fundamental understanding in this are remains limited, primarily due the challenges in isolating the interfacial thermal resistance and characterizing it without disturbing the interfacial transport. In the first part of my talk, I will show how we overcame these challenges with an ultrathin nanoporous membrane-based experimental platform. As a result, we elucidated a unified relationship for evaporative transport under different working conditions. In the second part of my talk, I will discuss how we leveraged the obtained understanding to create high-performance passive cooling solutions. For thermal management of electronics, we designed and microfabricated a hierarchical evaporator and demonstrated a record pure evaporation heat flux for dielectric fluids. For temperature regulation of buildings and perishable goods, our hydrogel-aerogel structure exhibited significantly longer cooling time and delivered much higher cooling power by synergistically combining different cooling mechanisms. Overall, we show that combining fundamental interfacial transport physics with novel materials and interface engineering enables unique opportunities for innovations toward more sustainable energy and water technologies.