1. This document discusses using magnesium oxide (MgO) nanofluid in a heat exchanger to enhance heat transfer rate. MgO nanoparticles were dispersed in propylene glycol at concentrations of 0.1%, 0.3%, and 0.5% by volume. Experiments found that adding MgO nanoparticles increased the thermal conductivity of the fluid and improved the overall heat transfer coefficient, with the highest enhancement seen at 0.5% concentration. 2. The document reviews previous studies that examined using various metal oxide nanoparticles dispersed in heat transfer fluids in shell and tube heat exchangers. These studies found that adding nanoparticles increased the convective heat transfer coefficient, overall heat transfer coefficient, heat transfer rate, and effectiveness compared to