Cycle analysis of household SOFC combined heat and power system with internal steam reforming cells

In this paper, partial load efficiencies of three types of SOFC combined heat and power systems were calculated by cycle analysis. SOFC means Solid Oxide Fuel Cells. The systems were external fuel reforming system (ER type), internal fuel reforming system (IRa type) and internal fuel reforming system with different configuration (IRb type). In each system, the operating temperature of SOFC was 650◦C. The rated point of electrical power generation of SOFC stack was 560W. Fuel was assumed city gas 13A. At the rated points, results of electrical efficiency by cycle analysis were 39.1%, 41.4% and 41.4% at ER type system, IRa type system, IRb type system, respectively. Electrical efficiency of internal reforming system is higher than that of external system. However, the part load area of IRa type system was narrower than that of ER type system because heat recyle was difficult for IRa type system. The part load area of IRb type system was wider than that of IRa type system due to difference of configuration.