A brief review of some previous studies on the use of nanoparticles has been conducted. Some studies have presented the methods of preparing these fluids in different ways by looking at the different thermal properties of thermal conductivity, viscosity, density and specific heat. These properties are governed by Zinc Oxide (ZnO) nanoparticle that based on nano-fluids and their applications. In present work, some of methods and applications for nanofluids are summarized, also the procedure for formation of resistant nano-fluids. Empirical and analysis studies were investigated on ZnO nanoparticle for evaluating thermal hydraulic performance in heat exchangers and preparing samples of high quality and more stable. In spite of, many defies and problems not clear on nano-fluids which need to be emancipated using empirical applications.
