ZeroAvia completes ZA600 LTPEM PGS full flight profile ground test

Image courtesy ZeroAvia

ZeroAvia has completed a full flight profile ground test of its certification-intent low temperature proton exchange membrane (LTPEM) fuel cell power generation system (PGS) for the ZA600 hydrogen-electric powertrain.  

The test simulated a 250 nautical mile flight in a Cessna Caravan 208b aircraft, equivalent to flying between London Heathrow and Dublin Airport. During the two hour and 38 minute test, the fuel cell system demonstrated stable power output and excellent performance of the balance-of-plants, with each 200kW capable module producing 170kW power for take-off, 132kW during a 23-minute climb and 83kW for a 90-minute cruise. As part of the ZA600 hydrogen-electric powertrain for up to 20 seat planes, four 200kW rated modules of the dual stack PGS will provide electrical power for ZeroAvia’s 600kW electric propulsion system, recently the subject of G-1 and P-1 issue papers from the FAA.  

Each module is capable of feeding DC electrical power to four ZeroAvia 200kW rated inverters, which in turn provide AC power to one of four segments of the company’s proprietary 600kW motor design. The segregated system enables full power operation of the motor if there is failure in one leg, creating a high degree of fault tolerance.  

For the ZA600 engine, ZeroAvia has created a multi-stack balance-of-plant architecture capable of delivering 1.4 kW/kg power density. Since initial breakthrough flight tests, the company has been working to finalise the design of the certification-intent ZA600 as it works to certify with the UK CAA.  

The company also revealed today that it has been able to optimize the weight and operation of its ZA600 power generation system (PGS) through the design and development of a bespoke passive Venturi ejector device (in conjunction with supplier The Lee Company) for the recirculation of hydrogen gas within the fuel cell system.
  
The latest round of testing has seen the Venturi emulating the performance of a typical electrically-driven hydrogen blower but with many advantages. Where the heavy and bulky blower system draws parasitic power from the fuel cells, the Venturi does not, boosting the efficiency and overall specific power of the system. As a passive mechanical body, the Venturi also promises very low failure rates.  

ZeroAvia’s Venturi design also simplifies the certification of the system as it is reliant on the DO160G environmental qualification, as opposed to the more stringent DO254 for complex hardware that would face a system utilizing the electric blower.  

ZeroAvia’s ZA600 power generation system is the world’s first fuel cell module designed to meet CS-E and CS-23 certification requirements. The innovative balance of plant is en route to full certification and commercialisation and is well advanced in the requirements validation testing campaign.  

With both core components of the powertrain now in bench testing, ZeroAvia will move to full engine ground testing of the final design in the next few weeks. The rapid progression to this milestone for the ZA600 power generation system has been made possible by ZeroAvia’s strategy to invest in world class in-house testing facilities. ZeroAvia has built a 2MW capable fuel cell test lab at its Gloucestershire R&D centre. ZeroAvia’s fuel cell test lab is equipped with two bays, which has enabled testing the systems in an open frame environment, while also progressing the volume constrained, certification-intent system. 

Val Miftakhov, Founder and CEO, ZeroAvia, said: “We have shown the possibilities by flying a prototype of the ZA600 system on shorter range missions and we are now seeing the final design replicating customer needs in ground testing and pushing the boundaries of performance with new innovations. 

“What we have achieved with the Venturi is genuinely groundbreaking and further enhances an already commercially attractive, highly efficient and certifiable fuel cell propulsion system. This innovation is one of many that our team have brought into the design of this pioneering system, including novel humidification approach, novel gas distribution system and the multistack BoP architecture itself. Importantly, all of these innovations now have a clear and direct path to aviation qualification and certification.” 

ZeroAvia has already extensively tested a prototype of its first ZA600-engine aboard a Dornier 228 aircraft at its UK base. The company has also performed advanced ground tests in the US and UK for the key building block technologies for the ZA2000 system, including cryogenic tanks or LH2 and proprietary high-temperature PEM fuel cell and electric propulsion systems. ZA2000 will support up to 80 seat regional turboprop aircraft such as the ATR72 or the Dash 8 400.