Principal Investigator Evelyn Wang
Vapor condensation is routinely used as an effective means of transferring heat or separating fluids. Film-wise condensation, where the condensate completely covers the condenser surface, is prevalent in typical industrial-scale systems. Dropwise condensation, where the condensate forms discrete liquid droplets, can improve heat transfer performance by an order of magnitude compared to filmwise condensation; however, current state-of-the-art dropwise technology relies on functional hydrophobic coatings, which are often not robust and therefore undesirable in industrial conditions. Furthermore, low surface tension condensates, like hydrocarbons, pose a unique challenge since coat- ings used to shed water often do not repel these fluids.
We demonstrated a method to enhance condensation heat transfer using gravitationally-driven flow through a porous metal wick, which takes advantage of the condensate’s affinity to wet the surface and also eliminates the need for condensate-phobic coatings. The condensate-filled wick has a lower thermal resistance than the fluid film observed during filmwise condensation, resulting in an improved heat transfer coefficient of up to an order of magnitude and comparable to that observed during dropwise condensation. The improved heat transfer realized by this design presents the opportunity for significant energy savings in natural gas processing, thermal management, heating and cooling, and power generation.