Passive Anti-Frosting Surface Comprised of Periodic Micro-Grooves Containing Sacrificial Ice Stripes

To date, no surface technology exists that can passively suppress the growth of frost under chilled and humid conditions. Active techniques, such as applying heat or antifreeze chemicals to the surface, are energetically costly and/or environmentally harmful. The closest thing to a passive anti-frosting technology is the sprinkling of salt over a surface, which creates localized dry zones by virtue of the depressed vapor pressure of the salt. However, as the salt collects water vapor over time, it becomes diluted and eventually ceases to work as a humidity sink. Our invention proposes to use ice itself, rather than salt, as a humidity sink. Like with salt, the vapor pressure of ice is lower than for supercooled water at the same temperature. Therefore by fabricating an array of micro-grooves on a surface that contain stripes of frozen water, the dry zones between each ice-containing groove can overlap to keep the majority of the surface dry from frost and condensation. Unlike salt, the vapor pressure of ice does not change as it harvests water vapor, as the ice itself is also comprised of water molecules. The fabrication of the micro-groove arrays can be performed on virtually any solid surface/coating and could be done by a variety of methods including laser cutting, 3D printing, molding, etc. We expect that our passive anti-frosting surface technology will be of potential application for wind turbines, vehicles, airplanes, and heat exchangers in HVAC systems.

Patent Information:
For Information, Contact:
Grant Brewer
Senior Licensing Associate
Virginia Tech Intellectual Properties, Inc.
(540) 443-9218
Jonathan Boreyko
Saurabh Nath
Caitlin Bisbano
Grady Iliff