US-UK zero-greenhouse gas emission aviation company ZeroAvia announced on Friday that it had developed a high-performance compressor for hybrid-electric aircraft propulsion systems (that is, systems that use fuel cells to generate electricity which then powers electric motors). The company describes the development as a “world-first”, and the compressor is suitable for use with fuel cell systems of up to 900 kW capacity.

A challenge with using fuel cell stacks in aircraft is to ensure that they receive the high flow of oxygen they need for their chemical reactions to produce enough electricity to power the aircraft. Particularly at higher altitudes, air compressors have to be efficient and powerful. But they also have to avoid excessive weight, which would reduce aircraft payload and/or range.

ZeroAvia’s compressor has been specially designed to meet all the requirements for hydrogen fuel cell aircraft propulsion systems. Its initial tests have shown that it has a very stable performance across a wide spectrum of power settings and operating environments. The company reports that it has “many times” the power of any current fuel cell compressors and provides “superior” power density.

Its ability to support fuel cell systems of up to 900 kW means that it can be integrated as core element in the company’s first two hydrogen-electric propulsion systems. These are the ZA600, for use with 9-seat to 19-seat aircraft, and the ZA2000, for 40-seat to 80-seat aircraft. The ZA600 is aimed to enter into service by 2025, and the ZA2000 by 2027.

“The compressor technology we have designed is critical in delivering optimal performance in the final, certified ZA600 engine technology,” points out ZeroAvia chief technology officer: hydrogen Rudolf Coertze. “Our compressor is an important component of our fuel cell power generation systems, and a world-leading technology advancement for clean aviation in its own right. This really is a major achievement for our turbomachinery engineers and another marquee moment for the company at large.”

The compressor is weight-efficient. It has also been designed to operate with low latency, by means of a flow management approach that the company described as “innovative”. And it meets all aerospace standards and environmental conditions.

It runs on the power produced by the core electric propulsion system, meaning that it does not require the inverter and dedicated electric motor that are usually needed in fuel cell systems. This makes the system less complex, and fewer elements in the system both reduces weight and improves reliability. Less complexity will also aid the certification process for the company’s powertrains (certification testing will start during the next 12 months).