Passive anti-frosting cables

Buildup of ice and frost on overhead transmission lines compromises their integrity and also poses a danger to surrounding infrastructure and people. We present a passive anti-frosting cable design that keeps the majority of the surface free of condensation and frost, effectively preventing a continuous layer of ice from forming. The design consists of an array of rings, each containing a wicking micro-groove, that are evenly spaced across the aluminum cable. Water preferentially wets the grooves and freezes into ice rings at cold temperatures. As ice exhibits a depressed vapor pressure relative to liquid water, these ice rings act as overlapping humidity sinks. Two supersaturations were tested, an extreme supersaturation of 3 to best measure frost accumulation through video analysis and a supersaturation of 1.5 more reminiscent of real-life outdoor conditions. Regions between rings remained dry indefinitely beneath a critical ring spacing whose value depended primarily upon the supersaturation and secondarily upon the ring diameter. In contrast, continuous sheets of frost grew on aluminum cables that were smooth and initially dry, even when treated with a superhydrophobic coating. (C) 2019 Elsevier Ltd. All rights reserved.