Nanostructure-Coated Surface Technique Allows for Efficient Boiling & Condensation

Bryan Kilgore for Zondits, May 15, 2015. Image credit: Furmanj

Efficiency improvements to phase-change processes have an effect on many industries and systems that use boiling or condensing. Many systems rely on phase-change heat transfer, including refrigeration, boilers, HVAC, and heat exchangers. Improving the surface conditions of a heating or cooling surface is an important topic of research, especially for nanoscale structures, which tend to be expensive and difficult to create.

Mathew McCarthy, a professor at Drexel University, has developed a technique that uses a virus to generate complex nanostructure-coated surfaces with improved phase-change characteristics. One key property to nanostructured surfaces is the ability to delay the onset of critical heat flux (CHF) with boiling processes. CHF occurs when a layer of vapor covers the heating surface. This insulates the surface and causes an uncontrollable temperature rise, which can damage to the materials and components. The ability to delay CHF and keep a surface wetted at higher heat flux conditions means that higher heat transfer rates are possible before damage occurs to the material. A key advantage of this nanostructure manufacturing technique is that it’s fast and inexpensive.

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Hierarchical structures comprised of virus-templated nanostructures conformally coatings silicon microstructures. Image courtesy of Drexel University.

 

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