This document summarizes research on enhancing heat transfer rates in a shell and tube heat exchanger by using magnesium oxide (MgO) nanofluid. Experiments were conducted with MgO nanofluid at volume concentrations of 0.1%, 0.3%, and 0.5% as the working fluid in the heat exchanger. The results showed that adding MgO nanoparticles to the base fluid increased the thermal conductivity and heat transfer coefficient compared to using only the base fluid. The maximum enhancement of heat transfer was observed at a 0.5% volume concentration of MgO nanofluid. Equations for calculating heat transfer properties like overall heat transfer coefficient and Nusselt number are also presented and the results are discussed.