Dropwise Condensation by Nanoengineered Surfaces: Design, Mechanism, and Enhancing Strategies

Abstract Condensation is a common heat transfer process widely used in power plants, seawater desalination, and refrigeration industry. Highly efficient condensation is of great importance to save energy, improve operating efficiency of energy systems, and protect the environment. Compared with its filmwise counterpart, dropwise condensation has much higher heat transfer efficiency and is projected as the future condensation process. Various nanoengineered surfaces, including superhydrophobic surfaces, hybrid surfaces with different combinations of surface wettability, and slippery liquid‐infused surfaces, have been designed and applied to sustain and enhance dropwise condensation. In this review, the theories related to surface wetting and liquid mobility are summarized first, followed by an overview of the recent progress on these three major types of nanoengineered surfaces in dropwise condensation. Their contribution to heat transfer enhancement is also discussed, emphasizing on the promotion of nucleation and droplet departure. Given the critical impact of flooding in condensation heat transfer, studies that addressed flooding phenomenon at high subcooling are further reviewed. Various applications that use dropwise condensation surfaces are also summarized. Current challenges in dropwise condensation with nanoengineered surfaces are provided in the end, together with perspectives to accelerate its commercialization.