Abstract
Phosphoric Acid Fuel Cell (PAFC) stacks of 100 W (12 cells-125cm(2)), 250 W (16 cells-220 cm(2)and 6 cells-400 cm(2)) and 1000 W (30 cells-400 cm(2)) using external gas manifolds were designed, fabricated, assembled with "in-house" developed components at Energy Research Institute, KACST. These stacks were successfully tested for 300-1000 hours continuously to study their stability. The stacks were operated at 170-180 degrees using commercial H-2/CO2 gas and air at 1 bar. The electrical output power generated by the present stack was 1 kW (20.5 Vx50 A), which corresponds to a current density of 140 mA cm(2) at an average cell voltage of 0.7 V. From the successful operation of the stack, it was found that the stack was stable during its operation for 300 hours. Individual cell voltages, stack voltage, stack current, stack temperatures, stack power, stack resistance, flow rates of H-2, CO2 and air were recorded during the continuous operation of the 1 kW stack for 300 h using a Data Acquisition and Control (DAC) System. The heat generated in the 1 kW PAFC stack was sufficient to retain its temperature of 175-185 degrees C without any external heating. In this paper, the results obtained for the various stacks ranging between 100 W and 1000 W, and a description of the materials used in the development of the 1 kW PAFC stack, together with their approximate cost estimation are reported.