Refuelling Innovations

INNOVATION

ALRIGH2T will introduce cutting-edge ideas and technologies for hydrogen-based aviation, pushing the boundaries of current advancements in the field. The project aims to exceed the current state of the art by making significant contributions to the use of hydrogen in aviation, which is recognized as a promising decarbonization technology for the industry.

Concepts & technologies

A –
H2 SUPPLY & MANAGEMENT

Refuelling of LH2 – LINDE

Refuelling of GH2 – ADP

Safety requirements – SINTEF

B –
COMPONENTS FOR H2-POWERED AVIATION

Tank for LH2 storage – SAG

Direct refuelling instrumentation of tank & filling station – TEF

Specifications for H2 system integration – PAI

C –
VIRTUAL MODELS & TOOLS

Digital twin & simulation of the refuelling process – AIT

Virtual-Reality training of refuelling operator – DGS

Modelling & application to LH2 safety distance – SINTEF

D –
REFUELLING PROCESS

Refuelling technology evaluation – AIT

Airframe integrator-informed refuelling process – PAI

Safe protocols and training in case of accident – DGS

E –
DEMONSTRATION

Ground use of hydrogen – ATENA/TLD

GH2 handling in 2 airports – ADP/SEA

Rapid refuelling of LH2 via centrifugal pump (Linde facility) – LINDE

H2 SUPPLY & MANAGEMENT

Refuelling of LH2

Two methods are currently used for refuelling LH2: a reciprocating pump and pressurization by partial LH2 evaporation. The first method has a flow rate limitation of 200 kg/h, while the second method is inefficient due to the need to evaporate a significant amount of LH2 for pressurization, reducing available fuel.

Progress

ALRIGH2T will implement a new method for transfer of LH2 based on using of a centrifugal pump.

Innovative result

ALRIGH2T will develop a skid-based process unit for accelerated transfer of LH2 that will be commercialized.

refuelling of gh2

Progress

ALRIGH2T will demonstrate the end-to-end value chain using a modular storage and distribution of green hydrogen focusing on supplying hydrogen as a carbon-free fuel for aviation.

Innovative result

ALRIG2HT will develop and validate key hydrogen technologies, demonstrating a complete refuelling logistics chain in an airport environment. It will deploy a hydrogen-powered ground handling vehicle to enable a fully green turnaround. The project will also assess risks and define safety procedures to ensure the safe use of hydrogen, aiming to boost efficiency and support airport decarbonisation.

Safety requirements

Dangers linked with LH2 direct refuelling infrastructure includes hydrogen release and containment loss, posing risks of freezing, frostbites, fire, and explosions. Current systems require large safety zones to mitigate these risks, limiting simultaneous activities at airports. Safety systems and barriers aim to reduce the consequences of hydrogen spills.

Progress

ALRIGH2T will establish performance requirements for safety systems handling hydrogen in aviation. During the project, a thorough comparative assessment of risks associated with LH2 direct refuelling and tank swapping will be conducted to support planned demonstration campaigns.

Innovative result

ALRIGH2T will develop safety system requirements using a risk-based approach, focusing on systems whose failure could have significant impacts on people and the environment during airport operations and simultaneous activities.

COMPONENTS FOR H2-POWERED AVIATION

Tank for LH2 storage and instrumentation

Large LH2 tanks have long been employed in industrial contexts. An automotive company introduced smaller containers with a capacity of up to 8 kg, utilizing a vent-line system to release gas and reduce pressure during refuelling.

Progress

ALRIGH2T will produce,  assembly and validate  a complete LH2 tank system  featuring a distribution of sensors able to measure physical data and  stress sensors on tank walls allowing future simulations of the process.  

Innovative result

ALRIGH2T will validate sensor performance and extract detailed information on all phases of the refuelling procedure for optimal hydrogen capacity usage and functionality, alongside a robust safety concept.

Direct refuelling process & filling station

The refuelling of large amounts of LH2 from LH2 trailers to the internal aircraft LH2 tank, in a time compatible with normal airport operations, will require an accurate control of the whole process. Filling involves a rapid pressure increase, and inner fuel level sensors can’t accurately measure swap levels.

Progress

ALRIGH2T will develop a single automation control system that will integrate data acquisition from the tank, the auxiliary sensors and the fuelling parameters and the LH2 control system. This will enhance refuelling insights, and give inputs for the Digital Twin validation.

Innovative result

ALRIGH2T will enhance understanding of the whole refuelling process through diverse data parameters.

Specifications for H2 system integration

Aviation kerosene is a liquid at ambient temperature and pressure, easily stored within wing and fuselage tanks, but hydrogen is a gas at ambient temperature and pressure and needs to be liquefied at around -250°C to increase its energy density. The need for lightweight, well-insulated cryogenic tanks poses challenges for their design and distribution system.

Progress

ALRIGH2T will focus on studying fuelling & defuelling procedures and LH2 supply at airports, aiming to establish standards for future hydrogen-powered aircraft.

Innovative result

During ALRIGH2T, a key achievement in hydrogen system integration will be the establishment of the avionic bay for aircraft refuelling and the initial definition of interface parts standards.

VIRTUAL MODELS & TOOLS

Digital twin & simulation of the refuelling process

The Digital Twin (DT) is a digital model that replicates physical processes for real-time control and management. It requires accurate representation of the system through tests and simulations, constructing reduced-order models with key physical mechanisms. Existing DTs focus on automotive applications with non-cryogenic hydrogen, lacking global validity. LH2 applications face unique challenges such as high heat transfer during initial filling and nonlinear evaporation rates, necessitating tailor-made tank models.

Progress

ALRIGH2T will develop a DT for aircraft LH2 refuelling, merging high-fidelity simulations and fast parametric models, validated with experimental data.

Innovative result

ALRIGH2T will use the planned DT to support in- depth analyses of the whole refuelling process, , analysing parameters, enhancing real-time control, improving maintenance, predicting issues. This activity will go beyond test campaigns and will help reducing the time and costs associated with future LH2 refuelling system design, testing, and operation.

Virtual-Reality training of refuelling operator

The expertise gained in the development of IT technologies today allows to offer advanced solutions in Augmented Reality and Virtual Reality (VR) for comprehensive training services.

Progress

ALRIGH2T will create a VR scenario for realistic training of personnel in fuelling & defueling procedures. This ensures comprehensive preparation before the final airport demo.

Innovative result

A key outcome of ALRIGH2T will be establishing safe refuelling procedures for hydrogen aircraft and airport hydrogen supply. At the same time, VR serves as a commercial training tool for airport staff.

Modelling & application to LH2 safety distance

Existing hydrogen safety models mainly address gaseous releases, with limited focus on cryogenic hydrogen. While some models can be adapted, they often rely on simplifications from tests on other liquefied gases. Key challenges in hydrogen dispersion modelling include understanding the cloud’s behaviour based on density-wind equilibrium. Recent large-scale tests offer opportunities to validate existing models and develop new approaches

Progress

ALRIGH2T will enhance existing models and develop specific approaches for cryogenic releases. Key areas include improving release description, cryogenic pool spreading, evaporation, and hydrogen cloud dispersion.

Innovative result

ALRIGH2T will publish and apply an innovative model for the release source term and the pool spreading and evaporation.

REFUELLING PROCESS

Refuelling technology evaluation

There is no analysis comparing refuelling technologies across various metrics such as refuelling time, safety, economics, and scalability to different aircraft and airport sizes.

Progress

ALRIGH2T will plan to bridge this gap by conducting the first comparative assessment between classic direct refuelling, drawing from extensive demonstration campaigns. A demonstrator will occur in a large passenger airport, where hydrogen equipment must integrate with daily operations.

Airframe integrator-informed refuelling process

Safe refuelling operations require strict adherence to procedures and safety precautions by refuelling operators and other ground personnel. The main threat is fire, so three key aspects are considered: bonding, grounding, and refuelling safety zones.

Progress

ALRIGH2T will enhance airport fuelling procedures for hydrogen aircraft, prioritizing safety. New technologies will be evaluated, with demonstrations starting at the system level and progressing to full-scale aircraft refuelling at a gate, potentially utilizing LH2 at existing facilities for future fuel cell and gas turbine architectures.

Innovative result

ALRIGH2T will define feasible and safe procedures for refuelling hydrogen aircraft, as well as for the supply of hydrogen at airports.

SAFE PROTOCOLS AND TRAINING IN CASE OF ACCIDENT

Safe refuelling demands strict adherence to procedures and safety precautions tailored to the specific fuel type, particularly with the novelty of hydrogen fuelling. These procedures must adhere to aeronautical rules, undergo validation by authorities, and be incorporated into the airport operator’s manual.

Progress

ALRIGH2T will establish the foundation for crafting new regulations concerning fuelling and defuelling, which will be advantageous for all airport operators.

Innovative result

ALRIGH2T will define safe refuelling procedures and hydrogen supply protocols at airports.

DEMOSTRATION

Ground use of hydrogen

Airport emissions originate not only from aircraft operations but also from ground vehicles used in handling operations. Hydrogen fuel cells, particularly in proton exchange membrane fuel cells (PEMFCs), offer a promising solution to reduce emissions. PEMFCs, widely used in automotive sectors, are gaining traction due to hydrogen’s clean nature and its ability to address limitations of battery electric vehicles like operational time and recharging.

Progress

ALRIGH2T will develop and test a hydrogen-powered ground vehicle for aircraft servicing, starting from an already existing vehicle with a battery electric configuration. This builds on existing knowledge from the automotive sector, particularly in logistics applications.

Innovative result

ALRIGH2T will design, develop, and test a hydrogen fuel cell/battery hybrid ground vehicle for airport use. The vehicle’s performance will be demonstrated under real operating conditions.

GH2 HANDLING in 2 airports

Hydrogen and fuel cells in aviation, already demonstrated, are crucial for decarbonizing air transport. Airport operators must anticipate challenges and impacts on operations and design as hydrogen adoption grows.

Progress

ALRIGH2T will complement existing projects by preparing airports for a LH2 direct refuelling technologies and gaseous hydrogen refuelling technologies. The project aims to adapt airport masterplans, set up LH2 handling facilities, and prepare ground processes for both refuelling methods.

Innovative result

ALRIGH2T will facilitate LH2 aircraft refuelling demonstrations at airports, ensuring facilities, procedures, and safety measures are in place for normal and abnormal conditions. ALRIGH2T enables LH2 module handling, gaseous hydrogen ground movement and direct refuelling demonstrations, paving the way for LH2 aircraft operation and supply chain integration at airports.

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