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High powEr density FC System for Aerial Passenger VEhicle fueled by liquid HydrogeN

Periodic Reporting for period 4 - HEAVEN (High powEr density FC System for Aerial Passenger VEhicle fueled by liquid HydrogeN)

Reporting period: 2023-01-01 to 2023-09-30

The overall objective of this project was to address the gap between research and product stage of a zero-emission fuel cell (FC) based propulsion technology to achieve emission and noise reduction scenarios and meet the environmental goals for aviation towards the year 2050. To that end, a highly efficient, high power density fuel cell-based hybrid-electric propulsion architecture will be combined with the high energy density of cryogenic hydrogen storage and it will be advanced up to Technology Readiness Level 6.
This FC based powertrain will be developed and used for in-flight demonstrations on the experimental aircraft HY4 (2-4 PAX) to showcase aircraft relevant power density and range of the powertrain. The core value of HEAVEN was to transfer FC and cryogenic hydrogen storage technology from automotive and space technology to aircraft application, to advance it further and to build up technological know-how and use flight test data to validate the performance, range, efficiency and emission reduction capabilities of above technologies.
Several technical and logistical challenges were identified and solved with the expertise of HEAVEN engineers during the execution of the project. The project had successfully ended with the LH2 flight at Maribor Airport achieved on September 2023.The demonstration campaign verified the safe integration of the LH2 tank into the HY4 system. The flight tests covered a total of seven test flights, four of which were performed using LH2.
The main effort of the Partners in the last reporting period was on the implementation of all technology development to prepare the hydrogen fuel system, to be coupled, integrated in the aircraft and in the final flying activities.
In WP1 System Architecture the activities are finished. During the period activities on safety analysis and safety of flight were performed in more detailed to prepare the requirements to flight as planned during 2023.
In WP2 the fuel cell development plan has been changed according to the amendment. The work done was related to the anode heat exchanger, the use of a new GDL in the stack under development, modification of the FC-system to work with LH2 and the simulation of operation strategies.
WP3 Hydrogen Fuel System (HFS) finished during last reporting period. ALAT team focused on supporting WP4 (coupling tests) and WP5 (flight tests).
In WP4 System Coupling the work was focused on the system coupling activities, aiming to integrate the FC-system with the LH2 fuel system at test bed level, as well as testing the functionalities and performance of the coupled subsystems and the adaptation to the battery systems and drive train. This coupling was successful completed on Air Liquide’s Campus Technologies Grenoble, in France together with Air Liquide.
WP5 has been completed successfully, achieving the planned goals of demonstrating the technology in flight. The integration of the liquid hydrogen tank into the test aircraft has been led by PVS in collaboration with ALAT and H2F. This meant modifying the left fuselage to be able to house the tank together with all related subsystems, as well as performing the necessary structural tests to ensure safety of flight. In parallel, PVS and H2F guided the process of obtainment of Permit-To-Fly from the Slovenian Civil Aviation Authority, demonstrating quality of engineering processes, build and test procedures. The obtainment of the permit allowed to perform flight tests at Maribor Airport in Slovenia demonstrating the performance, operations and safety of liquid hydrogen as an energy source for aircraft electric propulsion. Throughout the whole project, this work package included also scalability studies on the developed technology, extrapolating the key performance and technical data of high-performance fuel cells and liquid hydrogen energy storage for larger, commercially viable aircraft and for unmanned aircraft platforms.
In WP6 dissemination and exploitation as well as in WP7 communication activities, the partners worked under PVS guidelines. During the period the dissemination and exploitation plans were updated and submitted. The communication activities were reactivated (website was updated and project information was presented in the communication channels) reaching the highest level after the successful LH2 flight.
WP8 Project management, the coordination with the support of all partners was working in the submission of all deliverables and reports to finish the project. In addition, during this period H2F have worked very closely to the technical team involved in the coupling and flying tests to assure the continuous communication that allowed HEAVEN team the agile resolution of several challenges coming during this reporting period.
The final success on HEAVEN working implementation was possible with the support of each partner, that contributed with their working effort, high-level experience and motivation. The LH2-flight was a historical achievement and the mayor HEAVEN milestone contributing to clean hydrogen and clean aviation objectives.
HEAVEN project proposed the development of a fuel cell (FC) system with high power and energy density for the propulsion of a 2-4 PAX demonstrator. The fuel cell system comprises two 45 kW PEM fuel cell stacks based on metallic bipolar plates and ready for mass production. This fuel cell system is adaptable to both small and large passenger aircraft (at least up to 19 PAX). It needs to be noted that the demonstrator airplane in HEAVEN will cater for zero-emission taxi, takeoff, climb, cruise and landing of the aircraft thus drastically reducing emissions and noise pollution. This is also fully in line with the ACARE SRIA Flightpath 2050 goals and goals of White Paper on Transport1, which is highlighting the importance of shift from fossil fuel dependency and reduction of green-house gas emissions by 80−95 % until 2050 as main general goals for transport suitability.
While HEAVEN high power and energy density FC-hybrid propulsion solution can be adapted to larger aircraft, testing the technology on large aircraft would first require massive investments in megawatt class ultra-lightweight engines, bringing delays to this perspective development.
By implementing the technological solutions first on small aircraft, which have favorable power-demands to conduct flight testing now, this narrows the horizon of commercial exploitation of the technology to years 2020-2030. Moreover, the scalability of the fuel cell system and the powertrain into small and bigger aircrafts as well as the extrapolation of the technology to UAV applications will be analyzed by using simulations during the execution of the project, providing inputs to the design activities to design towards the full modularity.

HEAVEN project implementation ended on September 2023. The longest LH2 flight achieved a maximum flight time over three hours under safe conditions. After this result, the potential for even longer flights was demonstrated. In addition, the campaign allowed the gathering of necessary data for scalability and simulation studies.
The campaign success was achieved by a motivated and collaborative test team represented by all project partners of the HEAVEN consortium. It is the flight test team’s opinion that such a success would have not been possible without the knowledge, spirit, and dedication of the whole team.
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