Phase change material infused surfaces for thermo-responsive condensation heat transfer for effective thermal management

Abstract

Recent advancements in applications such as data centers, electric vehicles, and avionics have led to a significant increase in heat dissipation rates. Two-phase thermal management systems (TMSs) including heat pipes, thermosyphons, and vapor chambers capitalize on the coolant's latent heat to achieve substantially higher heat transfer coefficients. In this context, the condenser surface, especially its wettability and topography, plays a crucial role in determining the overall heat transfer performance of TMSs. Recently, liquid-infused surfaces (LIS) have gained attention in condensation applications owing to their enhanced droplet mobility and rapid condensate removal. Here, we introduce a novel phase-variant liquid-infused surface (PV-LISs) having thermo-responsive properties, enhancing control of condensation heat transfer at TMS condensers. We utilize bio-friendly, food-grade coconut oil as a phase variant (PV) infusing liquid to design nanostructured CuO based PV-LIS. With a phase transition temperature of 25 °C, coconut oil infused PV-LIS is ideal for temperature-dependent control of vapor condensation in atmospheric conditions. The transition of the surface from wetting to non-wetting as the infused coconut oil undergoes a solid-to-liquid phase change with increasing condenser temperature results in contrasting condensate-surface adhesion states, enabling control of heat transfer performance. Through optical imaging and rigorous heat transfer measurements, we characterize water vapor condensation on PV-LIS across a wide range of surface temperatures. We demonstrate stable dropwise condensation of water vapor on PV-LIS, with the heat transfer coefficient being 3.8 times lower at low condenser temperatures and 1.9 times higher at high condenser temperatures compared to typical smooth copper surface. This work not only presents a method for achieving temperature-controlled condensation heat transfer rates but also establishes design principles for creating phase change material infused surfaces for ambient-centric two-phase thermal management systems.