<p>The industry’s most basic heat exchanger is usually the double-pipe kind. It may be adapted to fit different shapes and sizes. Using hybrid nanofluids (HNF), which demonstrated superior heat transfer efficiency over traditional fluids, the thermal performance efficiency of this exchanger was investigated in this study. HNF (MWCNT- Al₂O₃/water) was used to achieve this study. This fluid was manufactured in different concentrations, and the fluid concentration is one of the parameters of this study. The flow rate and fluid temperature were also parameters of the study, as variation of the flow rate caused the Reynolds number to change in the range of 1600–8000. By measuring the research variables, the necessary parameters were calculated to evaluate the exchanger performance. It was found that the Nusselt number value increases with increasing fluid concentration, increasing between 8.3% and 40.1% depending on the concentration and temperature. The exchanger efficiency increases by using hybrid nanofluids instead of conventional fluids in the range of 5-16.2%. Through the experiments conducted, an empirical correlation was derived to predict the Nusselt number value. Comparing the results of this research with previous studies in literature, we find satisfactory agreement.</p>