Nature-Inspired Boiling Enhancement by Novel Nanostructured Macroporous Surfaces

Authors


  • This work was supported by The Swedish Research Council for Environment, Agricultural Sciences and Spatial Planning (Formas). The fellowship from Knut and Alice Wallenbergs Foundation for Dr. M. S. Toprak is also thankfully acknowledged (No:UAW2004.0224). Supporting Information is available online from Wiley InterScience or from the authors.

Abstract

World energy crisis has triggered more attention to energy saving and energy conversion systems. Enhanced surfaces for boiling are among the applications of great interest since they can improve the energy efficiency of heat pumping equipment (i.e., air conditioners, heat pumps, refrigeration machines). Methods that are used to make the state-of-the-art enhanced surfaces are often based on complicated mechanical machine tools, are quite material-consuming and give limited enhancement of the boiling heat transfer. Here, we present a new approach to fabricate enhanced surfaces by using a simple electrodeposition method with in-situ grown dynamic gas bubble templates. As a result, a well-ordered 3D macro-porous metallic surface layer with nanostructured porosity is obtained. Since the structure is built based on the dynamic bubbles, it is perfect for the bubble generation applications such as nucleate boiling. At heat flux of 1 W  cm-2, the heat transfer coefficient is enhanced over 17 times compared to a plain reference surface. It's estimated that such an effective boiling surface would improve the energy efficiency of many heat pumping machines with 10–30%. The extraordinary boiling performance is explained based on the structure characteristics.

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