19-07: High Efficiency Heat Exchanger for Ice Energy Storage and Beyond

Freezing ice on coils is a slow and transient process that hinders the deployment of ice thermal energy storage systems for large commercial buildings. Here, we share observations of a novel interfacial phenomenon that was used to engineer an ice-phobic heat exchanger. Water drops that were frozen on the ice-phobic surface demonstrated extremely low interfacial adhesion, allowing the frozen drops to be shed off by body forces alone. Heat transfer coefficient measurements of this steady-state freezing process indicate improved performance over the traditional ice-on-coil process. Increasing the heat transfer coefficient reduces the necessary heat exchanger size, which decreases an ice thermal storage system’s footprint, important for high-density urban environments. These factors combine to substantially lower costs and increase applicability of ice thermal energy storage systems.