Design Specification 10

✍️Calculations: Accumulator

A fuel cell based on a proton exchange membrane is used as the power plant of the aircraft, paired with a battery. Calculate the composition of gases at the outlet of the anode and cathode chambers. Calculate the open circuit voltage, the power provided by the fuel cell. What hydrogen flow is required? What is the operating efficiency of a fuel cell? How will increasing the pressure to 10 atm affect the efficiency of work? (Take a fuel inlet pressure of 1 atm and an isothermal ideal compressor).

• Fuel cell based on a proton exchange membrane operates at 80 °C and 2 atm.

• 65% of fuel is used. The oxidizing agent is air. The air flow is such that the amount of oxygen at the inlet is twice as much as is necessary for the complete oxidation reaction to occur.

• The operating voltage of the cell is 0.65 V, the current density is 600 mA/cm2. The effective cell area is 220 cm2. A stack of 80 cells is used (cells are connected so that their voltages are summed up).