Ehsan Sharifara - Department of Energy Engineering and Economics, Faculty of Natural Resources and Environment, Science and Research Branch, Islamic Azad University, Tehran, Iran
Hossein Esmaeilli - Department of Energy Engineering and Economics, Faculty of Natural Resources and Environment, Science and Research Branch, Islamic Azad University, Tehran, Iran
Mohammad Ghanaatpisheh - Department of Energy Engineering and Economics, Faculty of Natural Resources and Environment, Science and Research Branch, Islamic Azad University, Tehran, Iran
Majid Khazali - Department of Energy Engineering and Economics, Faculty of Natural Resources and Environment, Science and Research Branch, Islamic Azad University, Tehran, Iran

Heat pipes are heat transfer devices which are widely used due to their higher effective thermal conductivity in comparison with conductive metals such as copper and aluminum. Several kinds of heat pipes exist such as pulsating heat pipe, rotating heat pipe, wick heat pipe, vapor chamber and thermosiphons. Heat pipes contain a fluid which evaporates by receiving heat at evaporator and then the vapor converts into liquid by heat dissipation in the condenser. Different types of heat pipes are categorized based on the returning mechanism of condensed fluid from the condenser to the evaporator. Nanotechnology is widely used in recent years in order to enhance heat transfer in several mediums as well as heat pipes in the form of nano-fluids or nano-surfaces. This paper gives a comprehensive review on the most recent applications of nanotechnology to enhance the performance of these heat pipes.

Nanotechnology, Nano-Fluids, Nano-Surfaces, Rotating Heat Pipes, Wick Heat Pipes, Pulsating Heat Pipes, Vapor Chambers, Thermosiphons, Micro Heat Pipes