Periodic Reporting for period 3 - TheMa4HERA (Thermal Management for the Hybrid Electric Regional Aircraft)
Reporting period: 2024-07-01 to 2025-06-30
The high-level objective of the project is to demonstrate the dissipation of required additional heat in the order of 20 to 50 kW for systems and 300 to 1000 kW for power storage and generation in batteries, the APU and fuel cells in future commercial aircraft. To give an order of magnitude for today’s aircraft falling under certification requirements of CS25/FAR25: 100 passengers generate approximately 10kW of heat in the cabin. Electrical appliances, in-flight entertainment, light, galleys, etc. may add another 10kW to the cabin. The avionics system generates approx. 15 kW of heat. In total, today’s aircraft thus produces an order of 35-50 kW heat.
The project will mature major technology bricks for the thermal management to TRL5. While the regional aircraft platform is considered for a seating capacity up to 100 passengers (minimum 50) with a range of 400-1000 Kms and Entry Into Service (EIS) 2035, the specificity of this project is that it also provides technology bricks for larger aircraft, namely the SMR segment.
Adherence to those objectives will be measured through the impact monitoring deployed at Clean Aviation level, and cascaded to each of the pillars
The project will mature major technology bricks for the thermal management to TRL5. While the regional aircraft platform is considered for a seating capacity up to 100 passengers (minimum 50) with a range of 400-1000 Kms and Entry Into Service (EIS) 2035, the specificity of this project is that it also provides technology bricks for larger aircraft, namely the SMR segment.
Adherence to those objectives will be measured through the impact monitoring deployed at Clean Aviation level, and cascaded to each of the pillars
During this period a new Use Case (UERA – Ultra Efficient Regional Aircraft) within the Hybrid Electric Regional thrust started to gain more importance, to which the TheMa4HERA consortium decided to pro-actively align and contribute. Some reviews were performed to better understand the concept and its needs in terms of thermal management, as well as identify the technologies potentially contributing to it.In order to further strengthen the collaboration, it was decided to invite the OEM developing this new use case to join the TheMa4HERA consortium.
Another challenge was to identify and onboard new UK Partners to take over the scope of bankrupted Partner Reaction Engines. This was also successfully achieved, with the new Partners formally onboarded at the end of Q2 2025 as part of the Grant Amendment, their activities having started at risk earlier than that in order to meet the compressed schedule.
Also part of the Grant Amendment, 2 distinct Fuel Cell cooling activities were launched, hence aligned to project HERA Use Case B.
Following some reviews gathering all the relevant stakeholders, M4 - Cabin Air Compressor (CAC) TRL4 was declared passed in August 2024.
The definition of the prototypes to be delivered and integrated to the various benches and demonstrators is well underway, along with their manufacturing. For the systems cooling demonstrator for instance, the convergence on technical as well as schedule aspects progressed, and a 3-steps strategy for the test set-up in Liebherr premises defined.
Several studies related to the SMR less-bleed architecture were launched. Maintaining those activities despite the bleed less architecture of the original HERA Use Case A and B proved useful since UERA could potentially benefit from that work (UERA having a less-bleed architecture)
Another emphasis has been to disseminate results. The single largest dissemination event was the “Thermal Management” session organized at EASN 2024 in Thessaloniki, Greece, during which several Consortium Partners presented their activities. Since the session proved successful, EASN organizers also offered a similar opportunity for EASN 2025 in Madrid, Spain, and for which many more abstracts were received.
Another challenge was to identify and onboard new UK Partners to take over the scope of bankrupted Partner Reaction Engines. This was also successfully achieved, with the new Partners formally onboarded at the end of Q2 2025 as part of the Grant Amendment, their activities having started at risk earlier than that in order to meet the compressed schedule.
Also part of the Grant Amendment, 2 distinct Fuel Cell cooling activities were launched, hence aligned to project HERA Use Case B.
Following some reviews gathering all the relevant stakeholders, M4 - Cabin Air Compressor (CAC) TRL4 was declared passed in August 2024.
The definition of the prototypes to be delivered and integrated to the various benches and demonstrators is well underway, along with their manufacturing. For the systems cooling demonstrator for instance, the convergence on technical as well as schedule aspects progressed, and a 3-steps strategy for the test set-up in Liebherr premises defined.
Several studies related to the SMR less-bleed architecture were launched. Maintaining those activities despite the bleed less architecture of the original HERA Use Case A and B proved useful since UERA could potentially benefit from that work (UERA having a less-bleed architecture)
Another emphasis has been to disseminate results. The single largest dissemination event was the “Thermal Management” session organized at EASN 2024 in Thessaloniki, Greece, during which several Consortium Partners presented their activities. Since the session proved successful, EASN organizers also offered a similar opportunity for EASN 2025 in Madrid, Spain, and for which many more abstracts were received.
The technologies developed in the project are foreseen to be developed beyond the state-of-the-art, up to TRL5:
- Cabin Air Compressor
- Vapour Cycle System
- Internal Heat exchanger
- Outflow valve
- UBV fan
- LH2 as Heatsink
- (non-propulsive) Fuel Cell cooling
- Skin Heat Exchanger
- Capillary Jet loop
- Micro channel heat pipe
- Pulsating Heat pipe
- Mechanically Pumped loop
With a TRL5 targeted at the end of the project, a clear further uptake is the maturation to TRL6 of the technologies deemed suitable for future Regional and SMR aircraft. This is planned in Phase 2 of the Clean Aviation program, that will include flight testing of the selected technologies.
Following the kick-off of the collaboration with EASA, there are indications that new regulations could be an outcome of the project (beyond the timeline of the project due to need to align with other regulatory bodies such as FAA, etc...)
- Cabin Air Compressor
- Vapour Cycle System
- Internal Heat exchanger
- Outflow valve
- UBV fan
- LH2 as Heatsink
- (non-propulsive) Fuel Cell cooling
- Skin Heat Exchanger
- Capillary Jet loop
- Micro channel heat pipe
- Pulsating Heat pipe
- Mechanically Pumped loop
With a TRL5 targeted at the end of the project, a clear further uptake is the maturation to TRL6 of the technologies deemed suitable for future Regional and SMR aircraft. This is planned in Phase 2 of the Clean Aviation program, that will include flight testing of the selected technologies.
Following the kick-off of the collaboration with EASA, there are indications that new regulations could be an outcome of the project (beyond the timeline of the project due to need to align with other regulatory bodies such as FAA, etc...)