Analysis of Transient Response Characteristics for Small Solid Oxide Fuel Cell (SOFC) Systems

摘要

The steady-state performance and transient response of the 1kW-class SOFC system was analyzed using the numerical model, since frequent load changes are often required. Based on the analysis, if the weight density of the catalyst is 100 g/m{sup}3 in the cell, the conversion rate of CH{sub}4 is about 80% even when the temperature of the reformer is 550°C. DC output of the system is 1262 W (54% (HHV)) at the rating when fuel utilization is 75%. In this case, the SOFC system can be operated thermal self-sufficiently at partial loads. Moreover the system maintains the same efficiency as the rating even if the fuel is decreased to 50% of the rating. The damping time constant of temperature for load change does depend on the flow rate of inlet gas to the system. The transient period of the SOFC system is influenced by the cell resistance dependence on the temperature.