Assessment and conceptual design of a SOFC/TIG/TEG-based hybrid propulsion system for a small UAV

Improving the electricity output of a propulsion configuration of an unmanned aerial vehicle (UAV) can be effective in achieving the targets of controlling fuel consumption and high flight endurance. Recently, fuel cell-powered UAVs have been developed to achieve these goals. In addition, the use of an integrated fuel cell-based electric propulsion system can further improve power generation rate. On the other hand, due to the limited reports on fuel cell-powered UAVs (especially solid oxide fuel cell [SOFC]), it is necessary to conduct more and detailed studies. In this regard, the present article provides a conceptual analysis of a SOFC/thermionic generator (TIG)/thermoelectric generator (TEG) integrated propulsion configuration to produce electric energy of a small UAV. SOFC stack converts chemical energy into electric current and thermal energy. The thermal energy of the stack's exhaust is converted into electric power under two processes in downstream generators. The objective of this work is to calculate the needful power of an UAV at desired mission requirements. The present study presents a new propulsion configuration. In addition, the proposed system's design and modeling as well as provided results are in such a way that the propulsion system can be generalized for any desired size of UAV. The finding revealed that the introduced propulsion configuration could produce nearly 553.7 W of electricity. Moreover, the efficiency of electricity production was close to 49.3%. It was also found that the drone requires nearly 1.3 kW of electric power to perform the intended mission. According to the conceptual evaluation of the proposed propulsion configuration, five scenarios are also suggested to provide the necessary power to the UAV.