Published 08/12/2024

Polar Technology develops innovative solutions for hydrogen storage

Conformable “Hydrogen in a Box” prototype for compressed gas storage has been tested to 350 and 700 bar, liquid hydrogen storage is being evaluated.

Edited by: Ginger Gardiner

Senior Technical Editor, CompositesWorld

Polar Technology Management Group (Eynsham, Oxfordshire, U.K.), an engineering business specializing in both metallic and composite technology, has a wealth of experience in the design, development and manufacture of technologies to support the “H₂ economy.” Leveraging expertise in lightweight, composite high-pressure cylinders and hydraulic accumulators, and also key developments in the area of cryogenic liquified gas storage down to liquid helium temperatures (-269°C), Polar Technology has developed composite solutions for compressed gas (CGH₂) and liquid (LH₂) storage.

These solutions have been focused on three main areas:

Lightweight cylinders offering industry-leading gravimetric efficiency,
The novel “Hydrogen in a Box Solution” where volumetric efficiency and space constraints of high-pressure cylinders are important
Technologies for the cryogenic storage of LH₂.

Polar Technology debuted a prototype of its “Hydrogen in a Box” solution at the 2024 Farnborough International Air Show (July 22-26). This multi-chambered storage vessel is said to offer 25% greater volumetric efficiency than current Type 3 and Type 4 CGH₂ storage tanks, enabling a more distributed storage solution with great promise for H₂-powered aircraft.

Hydrogen (H₂) storage is growing in significance for the aviation industry, with many viewing H₂ propulsion as a potential solution to achieve decarbonization. Currently, aviation emissions are responsible for 3.5% of climate warming caused by humans, indicating an urgent need to develop more sustainable alternatives. When generated from renewable sources, H₂ emits zero CO₂ emissions.

Identified as a key solution in 2020, the subsequent huge growth in H₂ development programs across the aviation industry is evidenced by Airbus’ commitment to flying H₂-powered aircraft by 2035 while ZeroAvia’s H₂ powerplant customers and/or demonstration partners include Airbus, American Airlines, KLM, Alaska Airlines, Joby, JEKTA, Textron Aviation, major aircraft lessors and more.

However, H₂ does pose several challenges in terms of fuel storage. Although it has the highest energy per weight, it also has the lowest energy per volume, being a very lightweight gas. This requires innovative solutions to enable efficient H₂ storage onboard the aircraft.

“This is an exciting time to be working on hydrogen storage solutions,” says Kieran Burley, Polar Technology’s lead engineer on the project. “There are so many opportunities for innovation, optimization and integration. Combining novel design solutions with innovative manufacturing processes means we can package hydrogen storage efficiently in a series of co-dependent chambers to form a storage bank, rather than fitting a number of standard independent cylinders into the space.”

“Hydrogen in a Box” offers significant flexibility in terms of geometry, opening new opportunities to efficiently store CGH₂ in places where traditional cylinders would not be appropriate, such as in the wings of an aircraft or under the cabin floor and possibly even as part of the structure itself.

Polar Technology’s solution minimizes the amount of empty or lost space surrounding traditional cylinders, as well as enabling the capacity to easily increase volume when required by adding more tank sections. Furthermore, “Hydrogen in a Box” has the capacity to integrate valves and control systems within the design, removing the need for extra manifolds yet it doesn’t require the use of a chassis to hold separate vessels together, unlike other conformable or chained tank products on the market.

“Enabling technologies for a sustainable and healthier future is rooted in our vision and ethos as an organization,” says Daniel Chilcott, business development director for Polar Technology Management Group. “Polar Technology’s solutions, such as ‘Hydrogen in a Box,’ can provide our customers significant overall system improvements and enable real advancement in hydrogen propulsion as well as CO₂ reduction.”

For more details contact: george.brown@polartechnology.co.uk