State of the art of heat transfer of heat pipes and thermosyphons employing nanofluids as working fluid

The paper presents an overview on recent research concerning heat transfer using two-phase devices, namely thermosyphons, heat pipes, and pulsating heat pipes using nanofluids as working fluids in order to emphasise their potential in heat transfer. Relevant experiments performed by the authors are presented in order to support the conclusions, together with some theoretical considerations about the heat transfer using nanofluids, their selection and application, and the effects of nanoparticle deposition due to nanofluid boiling. As shown, there is a significant potential of using nanofluids in two-phase heat transfer devices, and their success in improvement of the thermal performance of these devices depends on the transport of nanoparticles, which can occur if the vapour has the potential to transport the nanoparticles with it.