Improving the environmental impact of civil aircraft by fuel cell technology: concepts and technological progress

Nowadays, new technologies and breakthroughs in the fields of energy efficiency, alternative fuels and added-value electronics are leading to improved, more environmentally sustainable and green thinking applications. Due to the forecasted rapid increase of volume of air traffic, future aircraft generations have to face enhanced requirements concerning productivity, environmental compatibility and higher operational availability, thus effecting technical, operational and economical aspects of in-flight and on-ground power generation systems, even if air transport is responsible for only about 2% of all anthropogenic CO2 emissions. The trend in new aircraft development is toward ‘‘more electric’’ architectures which is characterized by a higher proportion of electrical systems substituting hydraulically or pneumatically driven components, and, as a result, increasing the amount of electrical power. Fuel cell systems in this context represent a promising solution regarding the enhancement of the energy efficiency for both cruise and ground operations. For several years the Institute of Technical Thermodynamics of the German Aerospace Center (Deutsches Zentrum f€ur Luft- und Raumfahrt, DLR) in Stuttgart and Hamburg has developed fuel cell systems for aircraft applications. The activities of DLR focus on: identification of fuel cell applications in aircraft in which the properties of fuel cell systems, namely high electric efficiency, low emissions and silent operation, are capitalized for the aircraft application; design and modeling of possible and advantageous system designs; theoretical and experimental investigations regarding specific aircraft relevant operating conditions; qualification of airworthy fuel cell systems; set up and full scale testing of fuel cell systems for application in research aircraft. In cooperation with Airbus, several fuel cell applications within the aircraft for both ground and cruise operation have been identified. As a consequence, fuel cell systems capable of supporting or even replacing existing systems have been derived. In this context, the provision of inert gas for the jet fuel (kerosene) tank and electrical cabin power supply, including water regeneration, represent the most promising application fields. This paper will present the state of development and the evolution discussing the following points: modeling of different system architectures and evaluation of promising fuel cell systems; experimental evaluation of fuel cell systems under relevant conditions (low pressure, vibrations, reformate operation, etc.); fuel cell test in DLR’s research aircraft ATRA (A320) including the test of an emergency system based on hydrogen and oxygen with 20 kW of electrical power. The fuel cell system was integrated into an A320 aircraft and tested up to a flight altitude of 25 000 feet under several acceleration and inclination conditions; fuel cell tests in Antares-H2—DLR’s new flying test bed

Fuel Cells For Aircraft Applications

Fuel Cell systems as power sources are a promising solution on board of commercial aircraft or motor glider aircraft. As well as power, fuel cell system can be a source of additional functionalities as inert gas and water provision for on-board purposes. This paper presents an overview of most of the progresses of the last past year to evaluate and demonstrate fuel cell design and capabilities on cruise and on ground operation. These results are really useful to for the possible future integration of fuel cell systems in new aircraft generation. Demonstration means like test platforms and tests results are shortly described as well as the way forward

Fuel Cell Systems for a Greener Aviation

The trend in new civil aircraft’s development is toward “more electric” aircraft and green sky. Fuel cell systems as possible part of the electrical supply in civil aircraft can allow reaching this target. Indeed fuel cell systems have high electrical efficiency, which can be used for on ground power generation and emergency power on flight, and are only producing water and oxygen depleted air as gas emissions. What it is also very innovative is that this “waste products” can be used to generate water on board and inert gas for the jet fuel tank as fire retardation and suppression measure. For several years the Institute of Technical Thermodynamics of the German Aerospace Centre (Deutsches Zentrum für Luft- und Raumfahrt; DLR) in cooperation with Airbus developed fuel cell systems which fulfil these functionalities for both aircraft ground and cruise operation. The main achievements of the last past years are the Antares-H2 development and tests as well as the successful milestones passed with the research aircraft DLR ATRA with fuel cell system test. This paper presents all the modelling and experimental activities of the DLR on fuel cell development for aircraft

Fuel Cells for civil aircraft application: On-board production of power, water and inert gas

Fuel cell systems are regarded as a promising solution for future electrical energy generation on board of commercial aircraft. In addition to an improved efficiency such systems offer the opportunity of producing water usable for on-board purposes and provide additional functions such as inerting (providing a non-inflammable atmosphere) of the jet fuel tank. This paper presents an evaluation and assessment of different system architectures as well as experimental results demonstrating the feasibility of the multiple functions in a laboratory set-up. First, the conventional system requirements and the results reported by the Federal Aviation Administration (FAA) are discussed. A system design evaluation based on simulating cruise and ground operation of aircraft is performed demonstrating the benefits of systems with pressurized hydrogen tank storage and cabin air use. The requirements for a fuel cell system regarding aircraft inerting function are calculated based on the FAA analysis. Experimental results based on laboratory systems confirm the feasibility of the implementation of various functions with a single fuel cell system. Test platforms for further investigation of the systems are shortly described