A Review of Condensation Frosting—Mechanisms and Promising Solutions

Abstract

Icing in the form of condensation frosting occurs ubiquitously in our daily life and numerous industrial applications. As the frost layer mostly comprises mixed microscopic dendrites and discrete air pockets, condensation frosting manifests a thick porous media and thus catastrophically compromises the heat transfer efficiency of HVAC systems. Despite being a popular research topic for centuries, a few unprecedented advances in the study of condensation frosting have been only achieved very recently, such as the revealing of new features in the incipient stages of frost formation, which used to be too fast or too small to capture, and new anti-/de-frosting techniques have been developed based on the revealed physics. This work provides a comprehensive, up-to-date review of condensation frosting, with an emphasis placed on progress in the very latest decade. Fundamentals of condensation frosting, including condensation nucleation, coalescence and growth of the condensed drops, icing nucleation, formation of frost halos, freezing propagation via ice bridging, and lastly densification and fully developed frost layers, are introduced chronologically as what occurs. A summary of recent engineering efforts to alleviate the negative impacts of condensation frosting, referred to as anti-/de-frosting techniques, is also presented. The results of these studies can greatly enlighten the existing understanding of condensation frosting and, meanwhile, benefit the development of new anti-/de- frosting methods for numerous application backgrounds.