Theoretical Energy and Exergy Analyses of Direct Methanol Fuel Cell

Joseph A.J; Abdulkareem A.S; Jimoh A; Afolabi A.S
This study studied the energy and exergy of direct methanol fuel cell (DMFC) through computer-assisted simulations. This was achieved through the development of mathematical models that represented the performance of a DMFC followed by simulations with a developed model using MATLAB. It was discovered that the simulated results conformed to the literature values with a correlation coefficient of 0.99 and standard deviation of 0.12. Simulations conducted with the developed model regarding the influence of operating parameters on the performance of the fuel cell indicated that maximum cell output voltage was obtained at a methanol concentration of 2 M. The results also showed that increases in temperature and operating pressure influenced the performance of the fuel cell. From the simulation results, it was seen that the maximum attainable energy efficiency of 95% was obtained at an operating temperature of 353 K, anode pressure of 1 atm, cathode pressure of 15 atm, and methanol concentration of 2 M, while the maximum exergy efficiency of 42% was obtained at the same parameters. It can therefore be inferred from the simulated results that improved performance, energy, and exergy efficiencies of a DMFC can be obtained by operating at controlled methanol concentrations and at temperatures that do not favour methanol cross-over or activation and concentration losses. Operating at a cathode pressure that is higher than the anode pressure can also enhance the performance of a fuel cell. Simulated results showed that cell performance depended on operating conditions; however, care must be taken in actual use, as high operating pressure will affect the safety and cost of operation of the cell because auxiliary equipment will be required to operate the cell at higher pressure.
Computer Simulation; Energy and Exergy; Mathematical Modeling; Methanol Fuel Cell
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