Heat transfer is one of the most important processes in many industries. Base heat transfer fluid like water normally is having low thermal conductivity. Since thermal conductivity is considered as important factor for rapid cooling and heating application, advanced heat transfer fluid called nano fluid is introduced. Nano particle is low concentration cooling agent which uniformly scattered in nano fluid Suspensions of Nano particles shows better enhancement of stability, heat transfer capabilities and reduction of particle clogging. All researchers tried to increase the heat transfer rate by controlling the parameters like shape, size, clustering, collision, porous layer, melting point of nanoparticle. Previously we were using only refrigerant as working fluid in heat exchanger for cooling purpose. The presence of fluorine and chlorine make the refrigerant non toxic. Hence the whole world attracted towards the Nano fluid. Finally this project is to be carried out through Concentric Double pipe Heat Exchanger with base fluid water and nano particles like MnO2. Study is made to ascertain the effect of Nano fluids in enhancing the effectiveness of heat exchanger by varying the concentration of nano fluids.