A New Evaluation Strategy for Nanofluid Usage as a Coolant in PEM Fuel Cells

Nanofluids exhibit higher thermal performance than conventional fluids and are preferred as cooling fluids in thermal management of polymer electrolyte membrane (PEM) fuel cells. In order for a nanofluid to be used in PEM fuel cell cooling, it should have high stability, high heat removal performance, and low electrical conductivity (EC). In this study, the utilization of Fe₃O₄-water nanofluid in PEM fuel cell cooling was investigated using a novel technique that considered all three of these features into account. The nanofluid was synthesized in varying mass ratios of 0.1%–0.5% and its thermophysical properties, EC, and zeta potential were measured. According to the findings, when EC and stability were taken into account, the pH value of the Fe₃O₄-water nanofluid should exceed 7. The thermal performance of the nanofluids was assessed using the performance evaluation ratio (PER), Mouromtseff number (Mo), and h_r under both laminar and turbulent flow conditions. A maximum heat transfer improvement of 19% for laminar and 18% for turbulent flow conditions was achieved at a mass ratio of 0.4%. In addition, an artificial neural network (R² = 0.9999, MSE = 0.000944) was used to model the EC. For the first time in the literature, a correlation was proposed to predict the EC of a nanofluid on the basis of pH and mass ratios.