Abstract: In the present study, the exergy transfer characteristics of (Ethylene glycol+ Alumina) nanofluid and Ethylene glycol fluid flow through a circular duct with constant wall temperature for hydrodynamic and thermally fully developed laminar flow have been considered. To examine the exergy transfer rate, the nanofluid is assumed to be single phase and the effects of nanoparticles enter in the physical characteristics of base fluid. The basis of single phase model is the fact that solid particles in nanofluid are ultra fine(less than 100 nm) and are easily fluidized. In this manner, nanofluid can be treated as a pure fluid. Volume fraction of nanoparticle assumed to be 0.1 in nanofluid and zero in pure fluid. The Results show that exergy destruction in nanofluid is higher than base fluid. But there is a maximum point of exergy loss along the duct and after that, exergy destruction, decreases.