Nanofluid, suspension of nanometer-sized particles in fluids (water, ethylene glycol, propylene glycol), has been greatly promised as a means of heat transfer in recent years. However, it is essential to have a good understanding of the physical method of heat transfer in such fluids. The enhancement of heat transfer by natural convection in a vertical cylindrical enclosure using nanofluids is reported in the present study with one end heated and the other end cooled. An experimental study highlighted an allegedly incongruous behavior of the heat transfer declination. The study examined the nature of this declination and its subjection to parameters such as the concentration of the particles, the configuration of the cavity which contains them and the material of the particles. Miniaturization has become a trend in the modern world, as the saying “Bigger is better” paves the way for “Smaller is better”. Industries need compact equipment that reduces space consumption and also works efficiently in heat transfer applications. Heat transfer in a closed chamber has many technical applications such as automotive, aerospace, boiler rooms, cooling of electronic components, heat exchangers and many others. Heat buildup in a particular location will cause discomfort and result in poor performance. Many methods and experiments have been carried out to remove the excess heat generated. Natural convection is a heat transfer mechanism used in several applications. Suspensions of a dispersed phase in the form of small particles in the base liquid phase play an essential role in the food and pharmaceutical industries as well as in the refrigeration industry. Years ago, it was observed that improving the thermal properties of liquids could be achieved through one of the characteristics of suspensions. Many micro and ...... middle of paper ......es, highest heat transfer rate at Ra=109 and L/D=75mm. Figure b shows that the heat transfer is higher at a higher concentration level of the nanoparticle. The enhancement of convective heat transfer over a water-based nanofluid in a closed cylindrical chamber is tested experimentally in the present study. This study presents the experimental details of the silver/water nanofluid with water and at different concentration levels. It is obvious that the heat transfer rate can be increased by the addition of nanoparticles with higher volume concentration. The observed results show that silver/water nanofluids exhibit better heat transfer characteristics than water. With the given heat inputs, the nanoparticles showed an increase in heat transfer of 47% at a concentration of 0.01% and 55% at a concentration of 0.03%. The choice of nanoparticles dependent on proliferating Nusselt is proven.