Thermal Engineer– Cooling System Expert - Innovation Team, Sion

About H55 As the technological spin-off of Solar Impulse, the first electric airplane to fly around the world, the mission of H55 is to make aviation clean, safe, and affordable. H55 exists to accelerate this transition by building the certification‑grade energy platform that electric aviation needs to scale, delivering energy storage systems that are predictable, provably safe, and trusted by authorities, insurers, and OEMs. Because in aviation, innovation only matters when it can fly.

Your Role As part of the Innovation Team, you will develop advanced cooling and thermal management solutions for electric aviation systems, including batteries, power electronics, and electric propulsion units. You will contribute to early‑stage technology development, combining thermal simulations, system modelling, and experimental validation to evaluate new cooling architectures and improve system performance, efficiency, and reliability. Your work will directly support the development of next‑generation, certifiable electricpropulsion systems. You will work closely with multidisciplinary engineering teams to translate concepts into validated solutions.

Main Responsibilities

Design and develop thermal management and cooling systems for electric aviation applications, including batteries, power electronics, and propulsion components

Perform thermal simulations and CFD analyses to evaluate cooling performance and identify design improvements

Develop thermal models and system‑level simulations for early concept evaluation and architecture trade studies

Investigate advanced cooling technologies, including liquid cooling, two‑phase cooling, immersion cooling, and phase change materials

Support the design, integration, and testing of thermal prototypes and experimental setups

Analyze experimental data and correlate results with simulation models

Collaborate with electrical, mechanical, and software engineers to integrate thermal solutions into system architectures

Contribute to innovation projects and feasibility studies related to thermal management for electric propulsion systems

Help define thermal performance requirements and validation strategies for future platforms

Your Profile

MSc or PhD in Thermal Engineering, Mechanical Engineering, Aerospace Engineering, or a related field

Strong knowledge of heat transfer, fluid dynamics, and thermal system design

Experience with CFD and thermal simulation tools (e.g. ANSYS Fluent, Star‑CCM+, OpenFOAM, COMSOL, or similar)

Experience modelling cooling systems or thermal management architectures

Familiarity with battery or power electronics thermal management is a strong asset

Ability to combine simulation with experimental validation and prototyping

Strong analytical mindset and ability to work in multidisciplinary engineering teams

What We Offer

The opportunity to work on cutting‑edge electric aviation technology with real‑world impact

A collaborative, international, and purpose‑driven team

Opportunities to grow into technical or leadership roles

A flexible and supportive work environment

An exceptional work location in Sion, Valais, in the heart of the Swiss Alps

You will have a direct impact on our products and on how we design and build them, working closely with cross‑functional teams in a fast‑evolving environment.

We are building a team where diverse perspectives are essential to solving complex engineering challenges and delivering safe, certifiable systems. If this role excites you but you don’t tick every box, we encourage you to apply.

Ready to help make electric aviation a certified reality? Let’s talk. Additional Information

H55 is committed to building a diverse and inclusive workplace. We welcome applications from all qualified individuals regardless of nationality, gender, disability, religion, sexual orientation, or age. Employment decisions are based on skills, experience, and business needs.

We are committed to providing an inclusive recruitment process. If you require any accommodations during the application or interview process, please let us know.

By applying for this position, you agree that your personal data will be processed for recruitment purposes in accordance with applicable data protection laws. Your data will be handled confidentially and retained only as long as necessary for the recruitment process.

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