Fraunhofer, DLR project demonstrates power for airliner galleys

German researchers have engineered a movable trolley cart for an aircraft galley (kitchen) that can provide supplementary onboard power. The unit was developed at the Fraunhofer Institute for Chemical Technology ICT in collaboration with Diehl Aerospace GmbH and the DLR German Aerospace Center, and made its debut at the recent Paris Air Show in France. Airplanes are built for several decades in service, but cabin furnishings and the galleys are renovated many times over the aircraft lifetime. This means that obsolete equipment is replaced by new, more power-hungry equipment. An auxiliary power unit supplies the required power when the main engines are not running, such as during boarding. But when new electrical loads are added in the passenger cabin, the entire aircraft power system has to be re-approved, because new devices could disrupt or even paralyse the power supply. This project has demonstrated a supplementary galley power unit, in the form of a movable trolley cart utilising using PEM fuel cells. Researchers at the ICT-IMM branch of the Fraunhofer ICT in Mainz engineered the system in partnership with the DLR German Aerospace Center and Diehl Aerospace GmbH, a joint venture between Diehl Aerosystems in Germany and French-based Thales. The work was conducted under the DIANA project within Diehl Aerospace's DACAPO (Distributed Autonomous Cabin Power) concept. The core of the innovative trolley is the fuel processor developed by Fraunhofer ICT-IMM, which comprises a reformer, integrated evaporator and superheater, and other components. The system uses liquid propylene glycol (3H8O2), which does not require a pressurised container, becomes non-flammable when mixed with water, and is non-toxic. It is already being used in aircraft as a coolant and de-icing agent. The reformer also transforms byproduct CO into non-toxic CO2. Fraunhofer researchers engineered the necessary catalysts, and ensured that the device takes up a minimal amount of precious onboard space. The cart can even facilitate the re-approval process, since it does not need new approval every time the airplane gets a retrofit or a face-lift. The research team has produced a mockup of the reformer, and they will assemble and test the first working prototype over the next few months. Last year Diehl Aerospace was granted a patent (US 8814086) for an aircraft onboard power supply system and galley that utilises a combination of low- and high-temperature PEM fuel cells to produce power and heat [FCB, January 2015, p16].