Effect of pressure variation on power density and efficiency of solid oxide fuel cells

This paper describes the effect of enhanced operating pressure on power density and efficiency of SOFC. Experiments were carried out with planar anode-supported cells which were operated at 1073 K with an anode gas mixture of 30% H2 and 70% N2. Pressure was varied between 1.35 and 8 bar. Points of polarisation curves were measured at steady state with fuel utilisation varying from 30 to 50%. Power density and efficiency of the fuel cell were analysed at different operating points. Results show that power density can be increased significantly (an increase up to 100% was measured) at constant efficiency. An increase in efficiency in the range of 10% is achievable if power density is kept constant. For all operating conditions, pressure effects show logarithmic behaviour.