As associated to straight tubes, helical tubes are more valuable because of its compact construction and it has been experienced as ace of the passive heat transfer improvement techniques and is being most widely practiced in several heat transfer applications. Many researchers are trying to improve the heat transfer rate in a helical coil heat exchanger. This Research paper shows the comparison between natural fluid and Nanofluid with the help of Computational Fluid Dynamics (CFD) on aluminium __ampersandsignamp; copper tubes. The Zinc oxide (ZnO) and Titanium oxide (TiO2) is used as nanofluid and water as its base.