Siltrax launches 2–6 kW air-cooled fuel cell system for off-grid applications

Australian hydrogen technology company Siltrax has launched the C2 Series, an air-cooled hydrogen fuel cell platform targeting unmanned aerial vehicles (UAVs), portable power systems and off-grid applications.

The company said the new fuel cell system covers power outputs from 2 kW to 6 kW, with a 3.6 kW configuration serving as a reference architecture for customer evaluation and system integration. Multiple modules can be operated in parallel to meet power requirements of up to 24 kW.

According to technical data published by Siltrax, the C2 stack measures 216 mm × 155 mm × 186 mm and weighs 3.48 kg, including its cooling fan. It has an operating temperature range of 40 C to 60 C and an ambient temperature range of -20 C to 40 C.

Siltrax lists volumetric and gravimetric power densities of 3.78 kW/l and 2.13 kW/kg, respectively, although the company notes that these figures apply to the cell block and exclude the endplates and fastening system.

The C2 uses an air-cooled architecture, with dedicated fans moving ambient air through cooling channels in the stack. According to Siltrax, this eliminates the pumps, coolant circuit and associated plumbing required by liquid-cooled fuel cell systems.

Unlike conventional open-cathode air-cooled fuel cells, the C2 features a closed-cathode design that separates cooling air from the cathode reactant-air supply. The company said this allows oxygen flow, pressure and filtration to be controlled independently while reducing the stack’s exposure to pollutants in ambient air.

The system also uses a dead-end anode configuration, which Siltrax said enables efficient hydrogen utilization without a continuously operating hydrogen recirculation circuit, reducing balance-of-plant components and system weight.

At the core of the C2 Series are Siltrax’s silicon-based bipolar plates, developed as an alternative to conventional graphite and metallic plates. According to the company, silicon enables thinner plates and reduced stack bulk, contributing to higher power density, while its corrosion resistance is intended to improve durability. Siltrax has also said the technology can leverage established manufacturing processes, equipment and supply chains from the solar and semiconductor industries, potentially reducing production costs as manufacturing scales.

The manufacturer is targeting applications where system weight and space are critical, including commercial and industrial UAVs, autonomous systems, mobile generators and remote power installations.

Siltrax said the C2 Series is commercially available, with customer integration programs and partner demonstrations underway in the Asia-Pacific region. The company will showcase the platform at the Hydrogen Technology World Expo in Hamburg, Germany, from Oct. 20 to Oct. 22.