Thermo-Electrical Behaviour of Al₂O₃ and SiO₂ Nanofluids in A Proton-Exchange Membrane Fuel Cell (PEMFC) Cooling Channel

Proton Exchange Membrane Fuel Cell (PEMFC) generates electricity through the reaction of hydrogen and oxygen. PEMFC is considered clean technology since the by-products of the reaction are only electricity, water, and heat. Thermal management of PEMFC can be further improved through the adoption of nanofluids as its cooling medium. Nanofluids are fluids that contain suspensions of nanoparticles in their base fluid. Nanofluids have better heat transfer performance as compared to their base fluid due to their significant thermal conductivity improvement. However, unlike any other heat transfer application, there is a strict limit on the electrical conductivity of the nanofluids due to their electrically active environment. Therefore, there is a possible current leakage to the coolant due to the nanofluids’ conductive behavior. In this study, heat transfer performance and current drop of 0.5% Al2O3 and 0.5% SiO2 water were investigated. The nanofluids were forced to flow in a charged channel subjected to a heater pad of 60°C to 70°C to mimic the operating condition of a PEMFC. The performance of each nanofluid was observed and compared to distilled water. The channel temperature was reduced by 43.3 % and 42.7 % by Al₂O₃ and SiO₂ nanofluids, respectively, compared to base fluids at Re 700. In terms of current drop, SiO₂ nanofluids have the highest current drop with 2.33 % from the initial current value. It was further justified with the increment in electrical conductivity value of the fluids after the experiment, thus justifying the current leakage hypothesis.