Liebherr-Aerospace is presenting its technology demonstrator of an aircraft emergency power system based on fuel cell technology at the Paris Air Show in Le Bourget. Liebherr uses the Fuel Cell Emergency Power System (FCEPS) to demonstrate how fuel cells might one day help to maintain the onboard electrical power supply after failure of engines and/or engine-assisted generators.
The emergency power generator most commonly used in aircraft until now is the Ram Air Turbine (RAT), which is automatically deployed in the case of loss of main power. Because of the way the RAT is designed, the amount of power it generates depends directly on the speed of the aircraft – if the aircraft slows down, the system will produce less power. In the final approach phase, the power output drops to zero.
The Liebherr FCEPS is fully integrated in the aircraft fuselage. As a result, it is not dependent on external airflow or weather conditions, and does not produce any aerodynamic drag. The choice of glide path is not affected. FCEPS delivers a constant power output throughout the glide phase, through to landing and taxiing on the ground. The installation of this system is subject to fewer restrictions than that of the Ram Air Turbine. This means that aircraft manufacturers can be more flexible in selecting where and how to install it in the airframe.
Like the Ram Air Turbine, FCEPS is only activated when required – that is, on failure of the primary power sources. The system is based on a low-temperature fuel cell that converts hydrogen and oxygen into water, heat and electric power. Integrated power storage modules enable FCEPS to deliver an uninterrupted power supply, so that electric power is immediately available on startup
The Fuel Cell Emergency Power System is a selected example of the results of interdisciplinary research by the Liebherr group of companies in the area of fuel cells. This system stands for an approach that could be the first of many applications for fuel cell technology in the aviation industry.
