%0 Journal Article %A Vasiliev, Leonard L. %A Grakovich, Leonid P. %A Rabetskii, Mikhail I. %A Vasiliev, Jr., Leonid L. %D 2013 %I Begell House %K thermosyphons, heat pipes, nanotechnologies, nanofluids, nanocoatings, polymer nanocomposites %N 4 %P 251-275 %R 10.1615/HeatPipeScieTech.2014011995 %T HEAT TRANSFER ENHANCEMENT IN HEAT PIPES AND THERMOSYPHONS USING NANOTECHNOLOGIES (NANOFLUIDS, NANOCOATINGS, AND NANOCOMPOSITES) AS AN HP ENVELOPE %U https://www.dl.begellhouse.com/journals/4b0844fc3a2ef17f,02db74f738465ef5,740718271edbdcc2.html %V 4 %X A new trend in heat pipes and thermosyphons application is related to nanotechnologies. Nanofluids, nanocoatings, and nanocomposites invention opened a new niche in the heat pipe and thermosyphon design and use. The aim of this work is to present a short review of some experimental results of heat pipes and thermosyphons application, using nanofluids, nanocoating and polymer composites made at the Porous Media Laboratory of the Luikov Heat and Mass Transfer Institute. The paper includes three parts to consider: Nanofluids, Nanocoatings and Polymer Nanocomposites. Nanofluids are investigated as a vacant working media for the transparent mini thermosyphons heated by a laser beam or solar radiation. Nanocoating is a thin porous layer in coaxial minichannels or minigrooves in the heat pipe evaporator that plays a role of additional centers for stable vapor generation, which do not require high superheating of the surface to obtain heat transfer enhancement. Porous nanocoating (thickness 25−100 μm) on the surface of heat pipe minigrooves improves the surface wettability, reduces thermal resistance (2−3 times), and increases the working fluid capillary pressure and permeability at the same time. New types of aluminum heat pipes with longitudinal minigrooves covered by micro/nanocoatings are developed and tested. Polymer composites reinforced by nanowires and nanoparticles used as a heat pipe and thermosyphon envelope are considered as promising alternatives to metals. A new design of a loop polymer-based thermosyphon was suggested, designed, and tested. The thermosyphon envelope consists of polyamide composite with carbon nanofilaments and carbon nanoparticles to increase its effective thermal conductivity up to 11 W/m°C, which is more than 40 times higher compared with thermal conductivity of a pure polymer. It was found that thermal resistance Rev of a flat grooved evaporator of the polymer thermosyphon is of the same order of merit as a classical aluminum smooth grooved heat pipe evaporator. %8 2015-02-17