Novel surface treatment technology was developed in the University of Paderborn in partnership with MiCryon Technik GmbH, Quedlinburg, Germany. The technology allows creation of micro-pin structures, which enhance the boiling heat transfer up to 18 times in comparison with a smooth surface, and provide an independency of the surface superheat on the applied heat flux [1–6]. The micro pins as basic structure elements can be created with the diameters of 0.1 μm to 25 μm at pins density ranging up to 109 pins/cm2. Such pin structures are created by electro-deposition of metallic ions on the basic surface. The microstructure provides for the very first time in thermal engineering a possibility to adjust the available length of the three phase line (TPL) on demand, correspondingly tailoring the shape of a boiling curve. The TPL, formed by the micro pins piercing the vapor-liquid interface, acts as an extremely efficient heat sink, providing high heat transfer coefficients and the constancy of the wall superheat at heat fluxes up to 125 kW/m2. Present article delivers the summary on boiling experiments performed with the novel microstructure, and reveals the quantitative dependencies of the heat transfer enhancement rate on the TPL length, having the pressure and the liquid type as further parameters. A newly discovered phenomenon of the vapor bubble chains formation on microstructured surfaces is discussed as well. Experiments were conducted with the refrigerants R134a, R141b and the fluorocarbon liquid FC-3284 at pressures, ranging between 0.5 bar and 9 bar.

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