Climate change is happening. We decided to launch a “Green and Clean” interview series to ask our alumni working in environmental careers how their companies and their work can lead us toward a greener future.


AFAM: Hello Julien. You are a R&D engineer at a French startup named Airthium. Please tell us more about your company and your job.


Julien: Hello and thank you for your interest. Heat pumps are a great technology for affordable and low carbon heat production, but existing solutions are limited to 200°C (400F). Airthium is developing a ultra-high temperature heat pump that will reach 550°C (1000F). This improvement will enable us to decarbonize new industrial processes, such as drying or steam generation, for various industries, such as paper, cement, chemicals, glass, mining, food and some heat networks.

My job at Airthium is to build a working prototype of a modified Stirling engine, capable of pumping heat at these temperatures. Another goal is to master a new process named Fast Near-Isothermal Compression. This would enable record-high efficiencies, and thus more energy savings.


AFAM: how did you break into this industry? Was it just a coincidence or a logical path in your career?


Julien: During my studies at Arts et Métiers, I led a team of 15 students that worked on a home hydrogen refueling station for cars. I started a company to study its commercial potential, but found that despite a record low price for a hydrogen station, it was not competitive enough against batteries.

When I was looking for an internship at the end of my degree, I had the opportunity to talk with Airthium executives about hydrogen compressors, which were a key technology in their previous research as well. By the end of the meeting, I had an internship at Airthium

AFAM: what do you enjoy the most about your job?

Julien: While trying to fight climate change at a large scale is of course satisfying, I especially enjoy following a technical project through all steps, from conception and manufacturing to assembly and testing.

AFAM: what is the most challenging thing about your work?

Julien: An experienced welder who worked on a part I designed at Airthium, told me that it was his most stressful job since he welded parts in the space industry. The reason for such difficulty is that I have to monitor many additional physical parameters during the R&D phase. There are also many constraints on the sensors we can use, such as operating temperature and pressure, with limited available space.

AFAM: How did Arts et Métiers prepare you for your current work? How does being a Gadz’Arts help you in your everyday tasks at work?

Julien: Doing R&D on a Multiphysics systems requires a deep understanding of various scientific fields, while mastering a wide set of skills. Arts et Métiers gave me both, plus the capacity to fill in any gaps by looking into literature. The Entrepreneurship and Technological Innovation course also gave me a taste of the fast-changing startup world.

While my two years of classes préparatoires gave me a solid scientific background, I would not have been able to manufacture a first prototype without the classes and projects I had at Arts et Métiers.

Finally, being a Gadz’Arts is helpful for introductions when I need extensive data from a company on their industrial process, which helps Airthium to evaluate its target market, and find potential customers. The Gadz’arts network is wonderful for helping each other and sharing information, and I am grateful to be a part of it.


AFAM: thank you Julien for your time



Photo: Airthium team (courtesy of Julien)

About Airthium


Airthium is a startup company headquartered in the US and operating in France with 12 employees, among which 6 PhDs. We are backed by Y Combinator (prestigious US startup accelerator), Accel'air (Air Liquide's accelerator, where we have our current lab) and personalities like Philippe Kavafyan (CEO Aker Wind) and Jérome Pécresse (CEO GE Renewable Energy).


Our team develops a very high-temperature industrial heat pump (up to 550°C) able to tackle 3% of global CO2 emissions (1 Gt of CO2). There is currently no green solution to economically decarbonize industrial heat production between 200 and 550°C.


We are launching a 2nd crowdfunding round of $5 million to accelerate the development of our technology, notably by moving to an industrial warehouse in September and supporting the current build of our 1 kW prototype.


Climate is changing fast, but there is still a chance to act !

You can invest in Airthium at and help us decarbonize our planet.


If you wish to know more, do not hesitate to make an appointment with us via our calendar