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Calyos selected by NATO’s DIANA Challenge Programme as part of the 2026 Cohort, to optimise cooling for mission-critical data centres
Charleroi, Belgium, December 12, 2025 – Following a very rigorous evaluation of over 3,600 proposals, Calyos, a Belgian technology company focused on advanced thermal management solutions, has been selected by NATO to join its prestigious DIANA (Defence Innovation Accelerator for the North Atlantic) programme under the Energy & Power challenge.
Data centres and compute platforms are essential infrastructure for both the civilian digital economy and modern defence operations. They demand high energy efficiency, robust reliability, and low dependency on local environmental resources such as water or stable power supply.
According to the International Energy Agency (IEA), data centres power consumption is expected to more than double by 2030. As cooling represents up to 40% of their total energy use, improving thermal management has become a critical lever for sustainability and operational resilience.
Calyos’ passive two-phase cooling technology has been selected by DIANA to help address this challenge by enhancing energy efficiency, sustainability and resilience in both fixed and deployable data-centre environments.
Calyos has developed unique two-phase cooling solutions that allow component cooling using the latent heat of vaporisation. Operating without pumps and requiring no maintenance, it can reduce cooling energy consumption by up to 50% while providing silent, reliable performance under harsh conditions such as vibration, dust, and extreme temperatures - qualities essential for mission-critical defence applications.
Founded in 2012, Calyos is a Belgian technology company of 20 people that designs, develops and manufactures innovative thermal solutions deployed across mobility, defence, and high-performance computing. The company is recognised by leading automotive, aeronautic and computing customers for its strong engineering capabilities and culture of innovation. Calyos solutions can be fully produced in Belgium and Europe, supporting strategic sovereignty and secure supply chains for defence.
With DIANA support, Calyos will upscale its passive cooling technology to cool servers and compute platforms used in ruggedised and tactical data centres, addressing the needs of both defence and civilian operators.
In the era of digitalisation, AI and climate change, cooling has become a mission-critical challenge.
The preparation for this innovative project was supported by A6K. “Over the past 18 months, A6K has worked alongside Calyos to drive its commercial acceleration. Calyos brings the kind of industrial expertise that strengthens Europe’s reindustrialisation and technological sovereignty. We’re delighted to join forces and to see the company selected for the DIANA Programme. Together, we’re ready to support the team’s next phase of growth.” says Sébastien Lewy, Acceleration Manager at A6K.
Calyos is backed by multiple investors and customers and continues to strengthen its position as a key European player in advanced thermal management, supported by new strategic partnerships currently under development.
© 2025 Calyos. Calyos selected by NATO’s DIANA Challenge Programme as part of the 2026 Cohort, to optimise cooling for mission-critical data centres [Press release, available above in French].
↘︎ Read the related articles in L’Echo by Olivier Gosset and in La Nouvelle Gazette by Morena Piazza for additional perspectives and insights.
