This problem has several parts. By following cach part, you will develop a simple fuel cell model similar to the one discussed in the text. (a) Calculate Ethermo for a PEMFC running on atmospheric pressure H2 and atmo- spheric air at 330 K (b) Calculate ae and bc (the constants for the natural log form of the Tafel equation for the cathode of this PEMFC) ifjo 10-3 A/cm2, n = 2, and ? = 0.5 CHAPTER EXERCISES 233 (c) Calculate ASRomic if the membrane has a conductivity of 0.1 ?-1 ·cm-1 and a thickness of 100 ?m. Assume that there are no other contributions to cell resistance (d) Calculate the effective binary diffusion coefficient for O2 in air in the cathode electrode. Neglect the effect of water vapor (consider only O2 and N2) and assume the cathode electrode has a porosity of 20% (e) Calculate the limiting current density in the cathode given ? 500 ?m. (1 To complete your model, assume c (the geometric constant in the concentration loss equation) has a value of 0. 10 V. Assume heak = 5 mA/cm2. Neglect all anode effects. Using some type of software package, plot the j-V and power density curves for your model. (g) What is the maximum power density for your simulated fuel cell? At what current density does the power density maximu m occur? (h) Assuming 90% fuel utilization, what is the total efficiency of your simulated fuel cell at the maximum power density point?