This study investigates the heat transfer characteristics of water-based graphene oxide (GO) nanofluids in an industrial-scale heat exchanger. An apparatus was scaled down from an industrial heat exchanger to a laboratory setup, and various thermophysical properties of the nanofluid were measured at different temperatures and GO nanoparticle concentrations. The results show that the thermal conductivity of the nanofluid increased with both temperature and nanoparticle concentration, peaking at 0.380 W m⁻¹ K⁻¹ at 85 °C and 0.1 wt %. The specific heat capacity increased with temperature but decreased with higher GO nanoparticle contents, reaching a maximum of 3403.82 J kg⁻¹ K⁻¹ at 40 °C and 0.01 wt %. The viscosity of the nanofluid increased with higher GO nanoparticle concentrations, with a minimum value of 0.83 mPa s at 85 °C and 0.01 wt %. The Prandtl number decreased with temperature but increased with higher GO nanoparticle concentrations, indicating a transition from convective to conductive heat transfer. A new correlation equation for the Nusselt number was derived, providing a valuable tool for predicting heat transfer enhancement in nanofluids. The findings highlight the potential of GO nanofluids in improving the performance of heat exchangers and offer insights into optimizing their applications in thermal systems.This study investigates the heat transfer characteristics of water-based graphene oxide (GO) nanofluids in an industrial-scale heat exchanger. An apparatus was scaled down from an industrial heat exchanger to a laboratory setup, and various thermophysical properties of the nanofluid were measured at different temperatures and GO nanoparticle concentrations. The results show that the thermal conductivity of the nanofluid increased with both temperature and nanoparticle concentration, peaking at 0.380 W m⁻¹ K⁻¹ at 85 °C and 0.1 wt %. The specific heat capacity increased with temperature but decreased with higher GO nanoparticle contents, reaching a maximum of 3403.82 J kg⁻¹ K⁻¹ at 40 °C and 0.01 wt %. The viscosity of the nanofluid increased with higher GO nanoparticle concentrations, with a minimum value of 0.83 mPa s at 85 °C and 0.01 wt %. The Prandtl number decreased with temperature but increased with higher GO nanoparticle concentrations, indicating a transition from convective to conductive heat transfer. A new correlation equation for the Nusselt number was derived, providing a valuable tool for predicting heat transfer enhancement in nanofluids. The findings highlight the potential of GO nanofluids in improving the performance of heat exchangers and offer insights into optimizing their applications in thermal systems.