SOFCMAN is developing 200kW SOFC system with a single hot box configuration. Such system consists of 192 stack modules. There stack modules are using cells in size of 14cmx14cm and total 25 cells. Large power SOFC system made of many stack modules needs great stack module consistency and stability, as well as stack module in low cost. Recently SOFCMAN measured a stack module having world record performance. Under furnace setting temperature of 700 degree, the stack showed 65A in discharge current and 20V in operation voltage, the average cell voltage of more than 0.8V, all cell voltages of more than 0.75V, electrical power output of 1300W, the fuel utilization of 94.3%, and electrical efficiency of 72.5% (LHV). The cathode outlet gas temperature in the middle layer of the stack was 820 degree in the stable operation conditions. The V-t and P-t curves are shown in the below picture. The testing was using city natural gas from pipe line with external steam reforming under 3 to 1 in steam to carbon ratio.

In a real system operation, one may not use such high fuel utilization because the reformer needs heat from the chemical energy of anode exhaust gases. The electrical efficiency is arguable because we calculated the power output divided by natural gas chemical energy. It is more accurate by counting stack inlet gas chemical energy. Nevertheless, it is encouraging that the high electrical efficiency has demonstrated what the stack performance could reach. There is a noticeable small degradation due to inlet anode gas without 100% reforming. CH4 percentage in the inlet anode gases was increased during the testing, that was also indicated by the stack reduced outlet gas temperature along the testing. Due to more internal reforming, the stack temperature was decreased gradually. We are dealing with this issue right now.

SOFCMAN sold many stacks around world with consistent performances. This performance shown is consistent in comparison with our 14cmx14cm 30-cell stack module. We have started to offer large power stack hot boxes in various power outputs up to 200kW in a single hot box form.