Effects of physical properties and operating parameters on numerically developed flat-tube solid oxide fuel cell performance

Abstract

Fuel cells are promising as a clean energy conversion device in the era of global warming threat. Solid oxide fuel cells stand out among other fuel cell types because they are especially feasible for high-temperature applications. Besides the operating parameters, which are frequently encountered problems in SOFCs, physical parameters also directly affect cell performance. For this reason, careful examination of the effects of the parameters while designing the SOFC will contribute to the increase of the maximum power to be provided from the cell in applications. In this study, a solid oxide fuel cell (SOFC) created in flat-tube geometry is numerically modeled. The effect of the electrode and electrolyte layers on the performance is investigated parametrically on the created geometry. In addition, the effect of temperature on cell power is investigated comparatively by making analyzes at different temperatures for each case. In the analyzes, performance values are investigated for electrode layer thicknesses of 0.75 mm, 0.5 mm, and 0.25 mm, and electrolyte layer thicknesses of 1.25 mm, 1 mm, and 0.75 mm, respectively. As a result of the study, the highest cell power is obtained at 0.25 mm of the anode layer thickness. The maximum predicted average cell power of the flat tubular solid oxide fuel cell (FT-SOFC) is approximately 68.2 mW/cm2 for the operating temperature of 1273 K. In the study, the effect of electrolyte conductivity on the performance of the developed cell is also investigated. It is observed that the cell with a conductivity value of 100 S/m at 1073 K operating temperature has the best performance. In addition, in the last part of the study, the performance of SOFC under non-uniform operating temperature conditions is also examined and a comparison is made for this situation, which is frequently experienced in practice. The results show that small changes in fuel cell operating temperature affect the cell performance in positive and negative directions depending on the increasing and decreasing temperature values.