Analysis of a 1 kW residential combined heating and power system based on solid oxide fuel cell

In this paper, a natural gas fueled 1 kW residential combined heating and power (CHP) system based on solid oxide fuel cell (SOFC) is established, and the conceptual design and mathematical analysis are presented. A quasi-two dimensional SOFC model and the system model which is proposed to predict the system performance are developed and validated, and the system performance under design-point condition is explored. The influences of decisive design parameters on the system performance and selection principle of design-point condition are investigated. The results indicate that the SOFC-CHP system designed in this paper can produce 1.005 kW electric power and 0.521 kW heating power. The system electric efficiency of 52.1% and cogeneration efficiency of 79.2% can be achieved respectively. The cell output voltage, system inlet fuel flow rate, and SOFC stack inlet air temperature affect the system greatly and non-monotonously. The resulting performance characteristics are obtained, which are of great significance for the design, optimization and safe operation of SOFC-CHP systems.