Managing thermal loads in hybrid-electric propulsion systems is a defining challenge for sustainable flight
As aviation accelerates toward electrification, one of its biggest engineering hurdles isn’t thrust, it’s heat. Managing thermal loads in hybrid-electric propulsion systems is a defining challenge for sustainable flight
Addressing this head-on, Conflux Technology has joined the Honeywell-led TheMa4HERA consortium – a major Clean Aviation initiative aimed at developing next-generation thermal management architectures for hybrid-electric regional aircraft.
Announced in September 2025, the collaboration unites 28 partners across 10 European countries, coordinated from Honeywell Aerospace’s international development centre in Brno, Czech Republic. The project, formally titled Thermal Management for Hybrid Electric Regional Aircraft (TheMa4HERA), focuses on new methods to handle the exponentially greater heat loads generated by hybrid-electric propulsion compared with today’s conventional aircraft.
A GROWING HEAT CHALLENGE
In traditional regional aircraft, thermal management systems must dissipate roughly 35–50kW of waste heat from onboard systems. In the hybrid-electric configurations envisioned under Clean Aviation, that figure increases dramatically to between 20–50kW for system-level cooling and up to 1,000kW for energy storage and generation components such as batteries, fuel cells, and auxiliary power units.
This order-of-magnitude increase in heat output demands a complete rethinking of thermal architecture, materials, and component design. Effective heat management is directly tied to system efficiency, weight reduction, and aircraft safety. Poor thermal control can degrade power electronics, shorten battery lifespan, and limit overall aircraft performance.
TheMa4HERA’s mission is therefore twofold: to innovate at the component level through developing advanced heat exchangers and cooling loops, and to validate new system-level architectures capable of efficiently distributing and rejecting heat in flight.
ADDITIVE ADVANTAGE
For Melbourne-based Conflux Technology, joining TheMa4HERA represents both an opportunity and a validation of its world-leading expertise in additively manufactured heat exchangers. Conflux has built a global reputation for designing compact, high-performance thermal components using metal additive manufacturing (AM), enabling intricate geometries and lightweight, integrated cooling solutions that conventional manufacturing cannot achieve.
Under TheMa4HERA, Conflux will contribute to several core work packages, including:
- Air Cycle Systems (ACS): Development of an air-to-air heat exchanger capable of managing dynamic temperature differentials under variable flight conditions
- Vapour Cycle Systems (VCS): Design and optimisation of air-to-liquid heat exchangers serving as both evaporators and condensers within closed-loop systems
These innovations are expected to advance heat exchanger technology to Technology Readiness Level (TRL) 5 by 2026, supported by digital twin modelling, virtual demonstrations, and ground testing.
“Joining TheMa4HERA aligns perfectly with our mission to deliver high-performance thermal solutions that enable low-emission, energy-efficient aviation,” says Michael Fuller, CEO of Conflux Technology. “Our additive manufacturing capabilities allow us to push the boundaries of design, achieving performance levels and weight savings critical to hybrid-electric aircraft.”
CONSORTIIUM COLLABORATION
Honeywell’s leadership of the consortium reflects its long-standing expertise in aerospace thermal and environmental control systems, including air management, avionics cooling, and electric propulsion integration.
“Conflux brings valuable technological capabilities to TheMa4HERA’s collaborative effort to develop the next generation of thermal management solutions,” says Jan Ludvik, senior director of advanced technology Europe at Honeywell Aerospace. “Each partner’s expertise strengthens our mission to deliver sustainable solutions that transform aviation.”
The consortium’s partners span the full ecosystem: OEMs, SMEs, universities and research institutes. This diversity enables cross-disciplinary innovation, combining aerothermal modelling, materials science, advanced manufacturing, and systems integration. By merging industrial experience with academic research, TheMa4HERA aims to generate a comprehensive set of validated design principles for scalable thermal systems.
The program’s Clean Aviation Phase 1 runs through 2026, focusing on subsystem and ground-based demonstration. Phase 2, beginning in 2027, will move toward flight testing and integration of the most promising designs in short- and medium-range hybrid-electric platforms.
ENGINEERING THE FUTURE OF SUSTAINABLE FLIGHT
Thermal management is foundational to achieving climate-neutral aviation by 2035, the central objective of the Clean Aviation programme. Without robust, lightweight, and efficient heat exchange systems, hybrid-electric and hydrogen-powered aircraft simply cannot operate reliably at scale.
Additive manufacturing brings a transformative advantage in this space. It enables complex internal geometries for enhanced heat transfer, reduced part counts, and integrated functionality, all of which contribute to lower weight and higher reliability. Moreover, the digital workflow behind AM lends itself naturally to simulation-driven design, parametric optimisation, and digital twin validation, core methodologies within TheMa4HERA.
The consortium’s research also explores system-level optimisation, combining air cycle and vapour cycle systems into hybrid architectures capable of managing both cabin and propulsion cooling requirements. By integrating thermal loops, designers can reduce duplication of components and achieve higher overall energy efficiency.
TOWARD CLIMATE-NEUTRAL AVIATION
TheMa4HERA’s broader ambition is to make hybrid-electric regional aircraft commercially viable within the next decade. By demonstrating scalable, certifiable thermal management solutions, the project will help de-risk the transition to new propulsion technologies – including battery-electric, hydrogen, and fuel cell powertrains.
Beyond the technical outcomes, the project is fostering a collaborative industrial ecosystem that spans Europe and beyond. For Conflux, participation in TheMa4HERA not only positions it within the forefront of Clean Aviation but also opens pathways to future partnerships in zero-emission aerospace.
“Thermal management is the unseen enabler of electrified flight,” Fuller says. “Through advanced additive design and collaboration within TheMa4HERA, we’re building the foundations for the next generation of sustainable aircraft.”
