Review and Evaluation of Solid Oxide Fuel Cell-Gas Turbine Hybrid System Design Choices for Aviation

Kurzfassung

Solid oxide fuel cells (SOFCs) have been identified as a potential technology for application in aviation due to their good performance characteristics compared to other fuel cell types and fuel flexibility. Due to the high operating temperature of SOFCs, there is potential to utilise them to improve the thermodynamic Brayton Cycle of a gas turbine (GT). Combined heat and power (CHP) cycles have already been proposed in the late 1990s and early 2000s. In contrast to stationary applications, the integration of SOFC-GT-hybrid propulsion systems in aviation causes additional challenges due to aircraft specific requirements, such as weight, packaging and dynamic operation. Within this study the focus is on a SOFC-GT-hybrid system as the primary propulsion system for an aircraft. In this paper, conceptual design choices for SOFC-GT-hybrid systems are evaluated through a utility analysis and critical components as well as challenges for the coupling of SOFC and GT are identified. A detailed overview including an evaluation of potential options for the different aspects regarding the coupling of an SOFC with a GT is given. As a result of the utility analysis, superior design options are identified, that could be considered when designing an aircraft propulsion system. Some of these preferred options are the singular SOFC unit and a multi shaft arrangement. These results can serve as a tool box for the further development process. Even though, a more detailed, holistic systemic evaluation will have to be carried out in order to account for synergetic and detrimental effects as well as dependencies.